Undergraduate Mapping Dissertation

University of Hull
A reconstruction of the timing, kinematics and geological evolution of
The Carboneras Fault Zone (SE Spain), using field observations.
Timing and kinematics
Geological Mapping Dissertation 2019-2020
In partial fullfilment of
BSc (Hons) Geology F600 Degree.
(Jack Connor)

Geological Mapping Dissertation - The Carboneras Fault Zone
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CONTENTS
LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER 1 – INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 - GEOLOGICAL SETTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER 2 – METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER 3 – RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 – BASEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.1 - Cortijada el Marques Graphite Mica Schist Formation. . .
3.1.1.a - Nevado Filabride Structure . . . . . . . . . . . . . . . . . . . .
3.1.2 - La Granitilla Formation . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.2.a - Alpujarride Structure . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.3 - Las Escalicas Red Siltstone Formation . . . . . . . . . . . . . . .
3.1.4 - Berenes Dolomitic Limestone Formation . . . . . . . . . . . . . .
3.1.5 - Malaguide Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 – STRATIGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 – VOLCANICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.1-Algarrobico Marl Formation . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2 - Cerro Gallardo Volcaniclastic Formation . . . . . . . . . . . . .
3.3.3 - El Ciscarico Red Breccia Formation . . . . . . . . . . . . . . . . .
3.3.4 - Volcanic structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 - SEDIMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.1 - Saltador Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.2 - Corjillo Portillo Sandstone Formation . . . . . . . . . . . . . . . .
3.4.3 - Garcia Marl Formation . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.4 - Molata Blanca Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.5 - Aguila Marl Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.6 - Molata Gypsum Formation . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.7 - Broton Marl Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.8 - Barranco Sandstone Formation . . . . . . . . . . . . . . . . . . . . .
3.4.9 - Sedimentary Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5 - FAULT ROCKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5.1 - Colada Gauge Formation . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5.1.a - Fault Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6 - INTRUSIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6.1 - Hoya Andesite Formation . . . . . . . . . . . . . . . . . . . . . . . . . .
3.6.1.a – Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3.7 - QUATERNARY GEOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER 4 - DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 - BASEMENT INTERPRETATIONS . . . . . . . . . . . . . . . . . . . . . . .
4.2 - VOLCANIC INTERPRETATIONS . . . . . . . . . . . . . . . . . . . . . . .
4.3 - SEDIMENTRY INTERPRETATIONS . . . . . . . . . . . . . . . . . . . . .
4.4 - COMPARISONS TO LITERATURE . . . . . . . . . . . . . . . . . . . . . .
4.5 - STRUCTURE TIMING AND KINEMATICS . . . . . . . . . . . . . . .
4.5.1 - BASEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.2 - VOLCANICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.3 - SEDIMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.4 - THE CARBONERAS FAULT SYSTEM . . . . . . . . . . . . .
4.5.5 - TIMING AND KINEMATICS . . . . . . . . . . . . . . . . . . . . .
4.5.6 - QUATERNARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6 - GEOLOGICAL EVOLUTION . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7 - LIMITATIONS OF PROJECT . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER 5 - CONCLUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LIST OF FIGURES
Figure 1. OS style map of proposed mapping area extracted from Ign.es (2019)......................................................7
Figure 2. A - Map depicting the regional tectonic structure of the Alboran Domain, extracted from Rutter et al
(2012) using information obtained from past sources (Lomergan and white,1997; Gutscher,2013). Adapted
to this figure is a depiction of the regional geology (Azañón et al,2012). B – Depitcing the stratigraphy of
the Nijar-Carboneras Basin based on findings of Fortuin and Krijgsman (2003), Van de Poel (1991) and
Haq et al (1987)............................................................................................................................................8
Figure 3. Graphical depiction of the order of stacking of the metamorphic basement – produced in CorelDraw. 10
Figure 4. Field Photographs, A – showing magmatic nature of the CMSf at L21.16-GPS:599007.100658. B –
showing porphyroblastic texture seen at L18.8-GPS:597601.99601.........................................................10
Figure 5. Annotated thin section photographs, A – showing grain boundary bulging of quartz grains. B – Showing
microfolds of graphitic minerals. C – showing schistose cutting pyrite minerals. D – showing muscovite,
quartz, biotite defined schistocity (Photos A-D taken of S7-GPS:590268,098477. E – showing wide photo
of thin section showing staurolite and chiastolite porphyroblasts taken of TS7-GPS:597601,099601. F –
showing mineral abundances of high-grade schist (TS7). G – showing mineral abundances of low-grade
schist (S7)....................................................................................................................................................11
Figure 6. A – showing schistocity of the CMSf recorded throughout the mapping area compared to those recorded
in the Sierra Cabrera, see key. B – digitised field sketch of folding within the CMSf within the sierra
Cabrera highlands. Both produced using CorelDraw. CorelDraw. ..........................................................12
Figure 7. Depicting observations of LGf. A – showing quartz, muscovite and chlorite defined cleavage. B – showing
relationship between cleavage and S0 silicic horizon. Pictures A-B taken of TS9-GPS:599251,101406. C –
shows picture of the interbedded nature of the Psammitic Member recorded at GPS:599445,101375. D –
showing mineral abundances of TS9. .........................................................................................................13
Figure 8. Showing observations of LGf’s structure. A – general trand of all cleavage recordings throughout the
area. B – data recorded within tectonic inlier at GPS:599500,101500. C – digitised field picture of folded
LGf showing axial planar cleavage recorded at L24.10-GPS:599445,101375. All produced in CorelDraw.
.....................................................................................................................................................................14
Figure 9. A – showing folded fault contact in Stereonet form, B – field photograph of striations parallel to the dip
of the fault plane recorded at L29.6-GPS:595989,098908, both produced in CorelDraw........................15
Figure 10. Generalised vertical section of volcaniclastic sequence to south and sedimentary sequence to the north,
comparison to literature are seen as per references within chapter 3.2. ...................................................16
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Figure 11. Field photographs of A – laminated white ashes recorded at L28.5-GPS:601742,101834. B – block ash
breccias recorded at L14.5-GPS:600602,100599. C – coarse rounded agglomerates recorded at L14.19-
GPS:600473,100769. D – hornblende crystals embedded in white ash recorded at L6.1-
GPS:595362,097939...................................................................................................................................18
Figure 12. Lithological images. A – field photograph of well exposed CRBf recorded at L8.22-GPS:598119,098572.
B – photograph of petrographic slide (TS5-GPS:600234,100497) showing iron stained rim of hornblende
crystal..........................................................................................................................................................18
Figure 13. Trend of data recorded throughout the volcanic sequence to the south of the Carboneras Fault Zone.
.....................................................................................................................................................................19
Figure 14. Showing the observation of the Saltador Formation. A – showing sedimentary log of unit recorded at
L17.2-GPS:595092,0987507. B – showing provenance grain abundances of sample. C – showing
horizontal burrows that were often seen recorded at L6.13-GPS:595623,098753. All produced in
CorelDraw. .................................................................................................................................................20
Figure 15. Showing different provenance compositional abundance of differing facies. A - Bioclastic Calc-
lithicarenite. B - Gravel Calc-lithicarenite. C - Homogenous Calc-lithicarenite. .....................................21
Figure 16. Showing field pictues of the CPSf. A – showing lower erosional contact with schist recorded at L16.2-
GPS:594164,098904. B – showing articulated mollusc shell fragment recorded at L1.23-
GPS:594428,098420. C – showing eroded gravel clasts out of unit recorded at L1.10-
GPS:594750,098483...................................................................................................................................22
Figure 17. Depicting thin section photographs of A-C showing TS1-GPS:594164,098929. D-E showing fossiliferous
unit of S3-GPS:590556,097253. .................................................................................................................22
Figure 18. A - showing graphic log of GMf recorded at L16.3-GPS:594224,098855. B – showing provenance clast
abundance of the two debrite deposits. C – showing benthic foraminifera included in marl horizons of TS2-
GPS:595082,098892. Digitised using CorelDraw. ....................................................................................23
Figure 19. A – showing graphic log with cyclical nature of the Aguila Marl Formation recorded at L17.1-
GPS:594158,098602. B – showing mineralogy of hardened marl recorded at S11-GPS: 594158,098602.
C - showing mineralogy of homogenous marl recorded at S11-GPS: 594158,098602..............................24
Figure 20. A – showing graphic log with cyclical nature of the MGf. B – showing picture of sample showing arrow
head gypsum growth. Both recorded at L29.10-GPS:591142,097553 and digitised using CorelDraw. ...25
Figure 21. Showing field pictures of BMf, A – showing dendritic growths at GPS:596590,097321 and B – showing
white fine-grained laminae recorded at L10.24-GPS:593602,098132. .....................................................26
Figure 22. Showing field observations of BSf. A – showing composite log recorded at L16.1-GPS:593303,097525.
B – showing clast mineralogy abundances recorded using S9-GPS:593303,097536. C – whole echinoid
fragment observed at L16.1-GPS:593303,097525. Digitised using CorelDraw........................................27
Figure 23. Showing the structure of the northern sedimentary sequence. A – showing minor alignment of platey
minerals forming slight cleavage recorded at L1.1-GPS:594425,098483. B – showing trend of bedding
data throughout the sequence, see key for info...........................................................................................28
Figure 24. Showing field observation of CGf. A – showing banded nature of gauges recorded at L25.13-
GPS:599882,101043. B – showing sediment rich gauge with relict bedding recorded at L21.25-
GPS:599497,101090. C – showing strated dolomite surface showing movement parallel to strike of fault
recorded at L12.15-GPS:595932,098789...................................................................................................29
Figure 25. Structural observations of CGf, A – showing R1 shears showing left lateral displacements. X shears
showing right lateral displacements. B – showing zoomed in left lateral P shears / foliation. A-B recorded
at L26.21-GPS:600301,101990. C – depicting trend of faults and slip llinaitions parallel to said faults.
Digitised using CorelDraw.........................................................................................................................30
Figure 26. Pie charts showing mineral abundances recorded using thin setions: A - S5-GPS:593738,097513, B -
TS12-GPS:600076,101002 and C - TS4-GPS:593505,097156 showing intermediate andesitic composition.
Digitised using CorelDraw.........................................................................................................................31
Figure 27. Rose diagram produced in GeoRose showing trend of HAf dykes throughout the area. Re-Digitised using
CorelDraw. .................................................................................................................................................32
Figure 28. Rose diagram produced in GeoRose showing trend of fluvial channels throughout the area. Re-Digitised
using CorelDraw.........................................................................................................................................32
Figure 29. Graphical pressure-temperature-time graph showing the likelt evolutionary path the LGf, high grade
CMSf and the low Grade CMSf took. Adapted from Winter (2010). ..........................................................34
Figure 30. Graph showing lomb scargle power spectrum showing frequency of cycles within the Af. And the lower
False alarm probability. Produced using MATLAB...................................................................................36
Figure 31. Subsurface cross-sectional interpretation along lines outlined on the accompanying A0 map poster. .40
Figure 32. Interpretive sketch of tectonic outlier at GPS:599497,101090, showing smaller scale asymmetrical folds
making regional folds. ................................................................................................................................41
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Figure 33. A - Interpretive box diagram of structure of volcanic sequence fold explaining the apparent cross cutting
relationship of the AMf and the CGVf seen at the surface. B – showing interpreted pre folding onlapping
structure......................................................................................................................................................42
Figure 34. A – showing box diagram of regional flower structure, showing transtensional geometries and
transpressive geometries along Cross section 4 (Fig.31). B – showing mohrs circle showing fault have
only propagated due to the phyllosilicate schistose basement its cutting through.....................................43
Figure 35. R.Dihedron stress inversion analysis, produced using win tensor, see key within figure to understand
figure. Top left of figure shows Frohlich classification showing predominantly wrench tectonics with both
trans-pressive and trans-tensile tendencies................................................................................................43
Figure 36. Diagrammatic depiction of the anticloscwise rotation of the stress field through A - Tortonian, B -
Messinain and C – Pliocene strata. Produced using Corel Draw..............................................................44
LIST OF TABLES
Table 1. Depicting the observations of the two members making up the La Granitilla Formation. ....................... 12
Table 2. Depicting the observations of the four members making up the Cerro Gallardo Volcaniclastic Formation
.................................................................................................................................................................... 17
Table 3.Depicting the four sub facies included within the Corjillo Portillo Sandstone Formation........................ 21
Table 4. Depicting the three facies making up the cyclical sediments of the Aguila Marl Formation.................... 24
Table 5. Depicting the three different characteristic fault gauges making up the Carboneras Gauge Formation. 28
Table 6. Showing the index minerals of each differential metamorphic unit and subsequent facies and zone
interpretation with formal names............................................................................................................... 33
Table 7.Depicting the variance of this study’s observations from those of the published literature....................... 37
Table 8. Depicting the geological history and sequence of geological events related to the time periods in which
they occurred in, with reference to major tectonic movements. ................................................................ 45
LIST OF APPENDICIES
Appendix A. Example geological field mapping slip, populated with an aerial image and OS map containing
lithological, structural data with full annotations…………………………………………………………... I
Appendix B. Example aerial imagery analysis underlay extracted from GoogleEarth and fully annotated tracing
paper overlay, used to transfer data from imagery to base maps………………………………………….II
Appendix C. Example geological logging template fully populated in field with textural, grainsize, structural, faunal
and sorting data…………………………………………………………………………………………………. III
Appendix D. Example geological field stereonet 15, assessing the structure of the volcanic sequence, later digitised
and implements into this report…………………………………………………………………………………IV
Appendix E. Example geological field stereonet 11, assessing the structure of the volcanic sequence, later digitised
and implements into this report…………………………………………………………………………………V
Appendix F. Key for provenance pie charts and sedimentary logs………………………………………………………..VI
INFORMATION
Georeferencing throughout the project has been completed using the Universal Transverse
Mercator zone 30S. Grid references are denoted, GPS: 000000,000000. Azimuth data has been
recorded with a positive eastward declination, +0 2’ from grid north, using methods outlined
by McClay(2013). Names of formations and members are italicised and individual to this
report. Nomenclature is denoted according to the geographical location, lithology and
hierarchy of the best exposed section of each mapped unit, at the authors discretion.
ACKNOWLEDGEMENTS
Many thanks are given to the University of Hull Geology Department for the partial funding
of the project and for the arrangement of appropriate health and safety training. Gratitude is
given to Prof. Mike Rogerson and Dr Eddie Dempsey for their guidance and assistance in
differing analytical methods, related to their fields of study.
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A reconstruction of the timing, kinematics and geological evolution of The
Carboneras Fault Zone (SE Spain), using field observations.
Jack Connor
Department of Geology, University of Hull, Cohen Building, HU6 7SZ, Hull
ABSTRACT
The Carboneras Fault Zone (CFZ) (SE Spain), forms a 1km wide damage-zone made up of
multiple anastomosing fault strands, often associated with cataclastic damage of basement rocks
of the Internal Betic Domain. The fault zone offsets Betic basement and post orogenic sediments
of the Nijar Basin against volcanics of the Cabo de Gata. This study and previous work note the
main movements occurred during the Tortonian, although previous studies have failed to address
how the rotation of the orthogonal stress field effected the CFZ’s slip rate. This study henceforth
aims to identify the timing, kinematics and type of faulting associated with the CFZ, to
understand if the Alpine orogenic activity ceased. Mapping at a 1:10,000 scale was undertaken
over a seven-week period, commencing on the 21st
June 2019, where the lateral variation of
lithology’s and structure of the CFZ was noted. The study not only shows the complexity of the
regions tectonic evolution, but also shows how the transpressive character of wrench systems
can influence thickness of sedimentary accumulations and shows how regionally conformably
contacts can be locally unconformable. Furthermore, not yet before addressed in the area, this
study assesses the effect upper-crustal faulting and incohesive fault gauge formation has on
quaternary surface processes.
1.0-INTRODUCTION
This report presents and summarises the findings of a 31-day field study research project, assessing
the kinematics, timing and geological evolution of The Carboneras Fault Zone (CFZ). Research was
undertaken by the author over a seven-week period, commencing on the 21st
-June-2019. The 12km2
study area was situated to the north of Carboneras, in the Almería Province. The NE-SW tending
study area, formed a parallel transect of the most northern continental outcrop of the CFZ. The study
area was demarcated prior to the field expedition and altered throughout the project; accordingly,
the final geographical location and area boundaries are as seen in Fig.1. The areas close proximity
to the semi-arid desert of Tabernas (Fernández et al., 2016), 24-miles west, gave it similar
environmental characteristics. Consequently, there is minimal vegetation cover of »35%, which
coupled with the rugged hilly terrain and dried incised river channels, gave high quality outcrop.
Thus, bed rock exposure was distributed evenly throughout the area, allowing some contacts to be
seen on aerial photos (e.g.Appendix.B).
The Europe-Africa N-S convergence, is responsible for the formation of the Alpine orogenic
complexes and its western continuation, the Betic Cordilleras (Zeck, 1999), as well as Tortonain
wrench tectonics (Rutter et al., 2012). Determining the timing and kinematics of movements along
the CFZ and reconstructing the geological evolution of the region, allows one to determine the faults
activity through time, giving an insight to whether the Alpine orogenic activity has ceased.
Furthermore, analysis of the impact the faulting has had on fluvial channel orientations, not before
addressed in the area, allows the local interrelationships between tectonics and Quaternary surface
processes to be unravelled.

pg. 7
1.1-GEOLOGICAL SETTING
The study area, situated in the southeast extent of the Betic Cordillera, is within the internal Betic
domain, which consists of three metamorphic complexes. From the base upwards these are; the
Nevado-Filabride Complex (NFC), the Alpujarride-Complex (AC) and the Malaguide-Complex
(MC) (Egeler, 1964; Augier et al., 2005; Lonergan & Platt, 1995; Booth-Rae, 2004). Together these
units form commonly metamorphosed piled nappe structures as a result of the Africa-Eurasia
convergence (Platt et al., 2003; Augier et al., 2005), as well as slab break off leading to vertical
ejection of material due to isostatic rebound (Zeck, 2004). Nappe deformation led to the
metamorphic alteration of the AC and the NFC, which reached eclogite facies with the later
greenschist overprinting as a result of decompressional retrogressive alteration (Tubía and
GilIbarguchi, 1991; Booth-Rea et al., 2003; Booth-Rea, 2004).
The landscape is characterised by Neogene sedimentary cover, within basins whose formation was
related to predominantly extensional Early and Middle Miocene deformation of the region (Booth-
Rae, 2004). This took place in the context of overall convergence between Africa and Eurasia
(Vissers, 2012). The sublithospheric mechanisms for this extension are still greatly debated in the
literature, however all entail the collapse of a thickened continental lithospheric root and orogenic
unroofing (Zeck, 1996; Johnson et al., 1997; Platt and Vissers, 1989; Vissers, 2012; Platt, 1989).
Figure 1. OS style map of visited mapping area extracted from Ign.es (2019).

pg. 8
The basins of southeast Spain show the most complete succession of the Mediterranean Messinian
salinity crisis, as well as recording 55 precession induced sedimentary cycles within the Abad
Member of the Sorbas and Níjar basins (Krijgsman, 2001; Sierro et al., 1999).
The onset of volcanism (27-30Ma) is coeval with the peak of metamorphism and the collapse of the
orogenic mountain belt, indicating that decompressional partial melting and asthenospheric
upwelling (Scotney, 2000; Turner, 1999), fuelled the regional volcanism. This led to the generation
of calk-alkaline magmas which erupted in the submarine environments of the Cabo de Gata
(Soriano, 2016) to the southwest of the CFZ in an island arc environment.
Influential strike slip movements initiated in the late Neogene where the Carboneras, Murcia and
Palomeras faults further accommodated the NNW-SSE convergence of Africa and Iberia (Booth-
Rae, 2004). These left-lateral faults are thought to be extensions of the Trans-Alboran Jebha and
Nekor faults forming the southern wall of the Betic-Alborán wedge, whilst the right lateral
Crevillente fault forms the northern wall (Gutscher, 2012; Meijninger & Vissers, 2006).
2.0-METHODOLOGY
A preliminary desk-study was undertaken, obtaining vector files of topographic base maps (IGN
Topográfico-Nacional-de-España, sheet 1031-IV, 1:25000), published in 1986 from IGME
(Instituto-Geológico-y-Minero-de-España). Vector maps were interrogated through ArcMap to
generate base maps at 1:5000 (e.g. Appendix A). Lastly prior to mapping aerial photographs were
extracted and analysed using Google Earth for later use in the field.
A field excursion consisting of an initial reconnaissance, where lithologies were observed and
sampled, the main grain of the area was identified, and hazardous areas were highlighted to
supplement daily risk assessments. Following this, geological mapping was undertaken, using
A B
Figure 2. A - Map depicting the regional tectonic structure of the Alboran Domain, extracted from Rutter et al (2012) using information obtained from
past sources (Lomergan and white,1997; Gutscher,2013). Adapted to this figure is a depiction of the regional geology (Azañón et al,2012). B – Depitcing
the stratigraphy of the Nijar-Carboneras Basin based on findings of Fortuin and Krijgsman (2003), Van de Poel (1991) and Haq et al (1987).

pg. 9
green-line exposure mapping (Lisle, 2011). However, where formation boundaries were apparent
on georeferenced aerial photography, overlay mapping (Lisle, 2011) was used by the means of
tracing-paper. Using said information contact mapping was implemented to confirm aerial
colouration changes were lithologically controlled. Due to high outcrop quality, exposure mapping
was not always appropriate, therefore, to cover sufficient ground transverse mapping (Lisle, 2011)
was used along dried river channels, roads and mountain-ridges. Throughout the mapping
procedure each mappable unit was named with a lithological, geographical and hierarchical
component. Between outcrops, lithological contacts were inferred three-fold using: vegetation
changes, areal imagery and stratum-contour relationships (Park, 2013). Irrespective of the mapping
technique implemented, a high volume of quantitative structural data was collected, using methods
outlined by McClay (2013). Collected data addressed features such as: faults, intrusion-
orientations, slip-lineation, schistocity, cleavage, fold-plunges and bedding-planes. Besides
mapping, several sedimentary logs were produced through post-orogenic strata. Logs were of
varying length depending on the height of the exposure and outlined the change in lithological,
textural and structural/bedding features (Appendix C).
Rock samples were collected throughout the area, using the spot sampling method (Coe et al., 2011)
using a geological hammer. Several were obtained from each formation, to assess the variation in
composition and differing appearance between fresh and weathered surfaces (Lisle, 2011).
Sedimentary samples were marked with way up indicators and where applicable, bedding and
cleavage of samples were recorded to obtain orientated specimens (Prior et al., 1987). Samples were
then numbered, georeferenced and bagged, however, sampling was done only where necessary in
areas making up part of the Cabo de Gata Natural Park. Samples were then cut and mounted on
slides for later petrographic analysis.
During post mapping exercises, clast abundances and mineralogy of formations were outlined via
petrographic analysis of collected samples. A second exercise was undertaken, recording
orientations of all fluvial channels at 50m intervals throughout the area, to assess their relationships
with the CFZ.
Structural data was interrogated through WinTensor to obtain a stress inversion analysis,
determining the stress field responsible for forming the CFZ. This is comparable to the technique
implemented by Rashidi (2019). Finally using calculated depositional rates (from, Sierro et al.,
2001) for the log within the Aguila-Marl-Member (See Page.24), the height of said log was
converted to time. Subsequently the log was processed using a Lomb Scarge Periodogram
algorithm, in MATLAB, to assess the frequency of the logs recorded cycles (VanderPlas, 2018).
3.0-RESULTS
For the reasons of clarity, this chapter will outline the authors field observations, quantitative
structural data alongside petrographic observations. Interpretations of the following results can
be found in Chapter 4. Throughout the study area many of the mapped units were heavily
affected by weathering, therefore throughout this section field observations will be used in
conjugation with Dearman’s (1974) weathering classification system to describe each lithologies
weathering profile.

pg. 10
3.1-BASEMENT
The basement rocks where characterised by the stacking of three tectonic units. The lowest of
the basement rocks were graphite-mica schists, corresponding to the Nevada-Formation of the
NFC-Bédar-Macel Unit, thought to be Permian and older in age (Alonso-Chaves et al., 2004;
Kampschuur, 1975). Tectonically overlying this unit was the Phyllite-Formation of the AC,
often containing quartzites in its upper section, which is Permian-Triassic in age (Alonso-Chaves
et al., 2004; Kampschuur, 1975). The highest of the three, correlated with the MC, which was
typified by red beds and dolomites of Permian-Triassic age (Alonso-Chaves et al., 2004;
Lonergan, 1993).
3.1.1-Cortijada-el-Marques-Graphite-Mica-Schist-Formation
The CMSf (Cortijada-el-Marques-Graphite-Mica-Schist-Formation), makes up the lowest and
oldest tectonic unit. The formation outcrops throughout the area but is unconstrained in
thickness, as its lower contact wasn’t observed. Heavy weathering often gave the formation a
soil like incohesive coating, however, in the absence of the weathered veneer, a clear penetrative
schistocity was observed. Between left-lateral fault strands, a porphyroblastic texture (Fig.4B)
and magmatic alteration was apparent (Fig.4A).
Petrographic analysis of the rock showed the schistocity of the entire formation was defined by
muscovite, biotite, quartz and graphite (Fig.5D). Within graphitic regions in thin section pyrite
was often found in abundance, cutting the schistose texture (Fig.5C), as were microfolds of the
graphite defined schistocity (Fig.5B). Samples collected from fault-bound regions showed a
higher metamorphic grade. Where abundant staurolite and chiastolite porphyroblasts were
3cm
A B
Figure 3. Graphical depiction of the order of stacking of the metamorphic basement – produced in CorelDraw.
Figure 4. Field Photographs, A – showing magmatic nature of the CMSf at L21.16-GPS:599007.100658. B – showing
porphyroblastic texture seen at L18.8-GPS:597601.99601.

pg. 11
present and were coupled with quartz rich strain shadows (Fig.5E). Separation of leucosomes
and mesosomes were apparent, as was grain boundary bulging of quartz minerals in silicic
horizons (Fig.5A).
3.1.1.a-Structure:
Within the highlands of the Sierra Cabrera, the schistocity was seen to be axial planar to tight
inclined similar folds, defined by relict S0 bedding of semi-pelite, psammite and graphite
2.5mm
A B C
D E
F G
St
Figure 5. Annotated thin section photographs, A – showing grain boundary bulging of quartz grains. B – Showing microfolds of graphitic
minerals. C – showing schistose cutting pyrite minerals. D – showing muscovite, quartz, biotite defined schistocity (Photos A-D taken of S7-
GPS:590268,098477. E – showing wide photo of thin section showing staurolite and chiastolite porphyroblasts taken of TS7-GPS:597601,099601.
F – showing mineral abundances of high-grade schist (TS7). G – showing mineral abundances of low-grade schist (S7).
Qz
Qz
Qz
G
G
G
G
G
B
P
P
P
Ch
St
Ch
B
M M
Qz
PPL | XPL
XPL XPL XPL

pg. 12
(Fig.6B). The almost vertical S1 schistocity in the mapping area, showed a differing trend to the
shallow (»34 Degree) north-westerly dipping schistocity of the Sierra Cabrera (Fig.6A). S2
folding of the schistocity was apparent in the mapped area, unlike the Cabrera highlands, where
open folds with horizontal axial planes gave the schistocity a somewhat corrugated structure. To
the north of the area a normal fault was present, with striations parallel to the dip of the fault
surface.
3.1.2-La-Granitilla-Formation
The CMSf sat tectonically below this formation with a faulted mylonitic contact, due to this
contact infrequently being observed, no shear-sense was obtained. The LGf (La-Granitilla-
Formation) frequently made up tectonic inliers to the south, in the centre of anticlinal folds of
Tortonian strata (GPS:595500,098800), as well as forming tectonic outliers within fault bound
areas to the north (GPS:599500,101500). The formation was made up of two distinct members.
Table 1. Depicting the observations of the two members making up the La Granitilla Formation.
Member Observation
Phyllite Member - Purple coloured when weathered
- Clear cleavage
- Low grade texture
- Strong phyllitic lustre
- High observed abundance of muscovite mica in the field
Psammite Member - Brittle
- Orange in colour in fresh and weathered surface
- Iron rich
- Formed relict S0 beds ranging from <1mm in thickens (Fig.7C)
to 10m thick bedded horizons
- observed within the tectonic outlier at GPS:599445,101375
A B
Figure 6. A – showing schistocity of the CMSf recorded
throughout the mapping area compared to those recorded in the
Sierra Cabrera, see key. B – digitised field sketch of folding
within the CMSf within the sierra Cabrera highlands. Both
produced using CorelDraw. CorelDraw.

pg. 13
The Phyllite-Member was confirmed to be phyllite through petrographic analysis, due to its fine
average grainsize of »20um and moderately formed cleavage defined three-fold by muscovite,
quartz, and chlorite (Fig.7A). Whereas the Psammite-Member was almost entirely made up of
granoblastic quartz with little mineral alignment.
3.1.2.a-Structure
The S1 cleavage of this formation (Fig.8A), more prominent in the Phyllite-Member, was broadly
concordant with the schistocity of the CMSf (Fig.6A). The almost vertical cleavage was seen to
be axial planar to relict S0 bedding surfaces in thin section (Fig.7B) as well as meter scale
asymmetrical, similar S folds of both members , which were secondary to large-scale folds with
wavelengths of >500m.
A B
C D
Figure 7. Depicting observations of LGf. A – showing quartz, muscovite and chlorite defined cleavage. B – showing
relationship between cleavage and S0 silicic horizon. Pictures A-B taken of TS9-GPS:599251,101406. C – shows picture of
the interbedded nature of the Psammitic Member recorded at GPS:599445,101375. D – showing mineral abundances of TS9.
Qz
Cl
S1 CLEAVAGE
S0 BEDDING
PSAMMITE
PHYLLITE
PPL | XPL PPL | XPL

pg. 14
3.1.3-Las-Escalicas-Red-Siltstone-Formation
The ERSf (Las-Escalicas-Red-Siltstone-Formation) was separated from the LGf, by a low angle
fault, where the LGf’s S0 bedding was often abruptly cut by fault planes. The formations
thickness was variable, thinning towards the SW. To the south the formations outcrop pattern
often traced around hilled areas (e.g.GPS:594500,097750), forming ring like mapped patterns
and to the north outcropped as linear features (e.g.GPS:60000,101000). The formation had a red
oxidised colouration and was void of any fossil remains. The grainsize ranged from silt-sand and
almost always showed evidence of lamination or bedding. No evidence of metamorphic
alteration was apparent in the field; however, very faint petrographic mineral alignment, gave
the formation a second fabric other than the bedding/laminae.
3.1.4-Berenes-Dolomitic-Limestone-Formation
The BDLf (Berenes-Dolomitic-Limestone-Formation), sat stratigraphically above the ERSf. The
contact between the two was characterised by an irregular erosive surface. However, the laterally
1m
3m
A B
C
Figure 8. Showing observations of LGf’s structure. A – general trand of all cleavage recordings throughout the area. B – data
recorded within tectonic inlier at GPS:599500,101500. C – digitised field picture of folded LGf showing axial planar cleavage
recorded at L24.10-GPS:599445,101375. All produced in CorelDraw.

pg. 15
un-continuous nature of the ERSf, meant this formation infrequently had a faulted contact with
the lower LGf (e.g.GPS:598000,100350). This contact was the same contact separating the ERSf
and the LGf, where the ERSf wasn’t present. This formation was often found to cap hilled regions
through the south of the area (e.g.GPS:595500,098800) and similarly to the ERSf outcropped as
linear features to the north (e.g.GPS:600000,101000).
The BDLf consisted of a heavily fractured dark coloured, dolomite which varied in composition.
In areas relict limestone textures and fossil fragments were observed (L28.10-
GPS:601430,101627), where dolomitization was less apparent. However, some areas were black
preserving no sedimentary features other than the relict bedding surfaces. The lateral distribution
of these two lithofacies weren’t fully resolved due to the formations often heavily weathered
brown colouration and hard brittle character making it very difficult to obtain fresh surfaces.
3.1.5-Malaguide Structure
Both the ERSf and BDLf made up the youngest sequence of basement rocks, which had differing
structures either side of the fault zone. To the north of the CFZ the units were often inclined and
were cut by extensional faults (L29.4-GPS:596113,098943), identifiable from striations showing
movement parallel to the dip of the fault (Fig.9B). On the contrary, to the S of the fault zone the
same units formed a large-scale fold around an intrusive body (GPS:601150,101850), with an
inclined axial surface. This is evidenced by the folding of the faulted contact between these
formations and the LGf, showing two clusters in Fig.9A. Both formations were rotated to vertical
parallel to the fault-zone to the northeast of the area (GPS:600000,101000), meaning the mapped
pattern formed linear features as there was no relationship with the uneven topography.
3.2-STRATIGRAPHY
The stratigraphy of the area was divided into two distinct sequences, separated by the CFZ. The
south of the fault zone saw a sequence comprised of both volcanic and sedimentary debris. The
A B
Figure 9. A – showing folded fault contact in Stereonet
form, B – field photograph of striations parallel to the
dip of the fault plane recorded at L29.6-
GPS:595989,098908, both produced in CorelDraw.

pg. 16
oldest sediments of this sequence are Burdigalian in age, consisting of marine marls (Serrano,
1990). Unconformably onlapping these marls was a volcaniclastic formation of Serravallian-
Langhian age (Rutter et al., 2012). Finally, this sequence was unconformably capped by the
Tortonain aged Brèche-Rouge (Uwe, 2003).
The northern sequence was purely sedimentary, making up the most northeast part of the Níjar-
Basin. The Saltador-Formation of Lower Tortonain age, made up the oldest unit (Fortuin and
Krijgsman, 2003; Van de Poel, 1992). Above this the Turre-Formation, which had a lower
Azagador-Member and an upper Abad-Member, was deposited during the Tortonain-Messinian
transition (Rutter et al., 2012; Braga et al., 2006; Huibregtse et al., 1998). Stratigraphically above
this lay the purely Messinian Yesares and Feos-Formations (Fortuin and Krijgsman (2003). The
youngest sediment, of a shallow marine lithofacies, unconformably capped the sedimentary
sequence and were a part of the Cuevas-Vejas-Formation of lower Pliocene age (Addicot et al.,
1977; Stokes, 1997). Comparisons to this paper’s nomenclature can be seen in Fig.10.
3.3-VOLCANICS
3.3.1-Algarrobico-Marl-Formation
The AMf (Algarrobico-Marl-Formation), makes up the lowest stratigraphic package of
sediment, reaching a thickness of 47m. The formation outcrops as a linear feature subparallel to
the CFZ, due to its steep inclined nature and non-conformably contact with the youngest
basement rocks (ERSf/BDLf). The formation was often weathered to the point where the original
Figure 10. Generalised vertical section of volcaniclastic sequence to south and sedimentary sequence to the north, comparison to literature are seen
as per references within chapter 3.2.
.

pg. 17
structure and texture of the rock was destroyed, leaving a light-coloured residual soil. In fresh
surface, the formation was again light in colour commonly containing a mix of both carbonate
and clastic material, of a mud/silt grainsize. Henceforth the lithofacies was classified as a marl.
Meter scale beds often fined upwards, where, medium sand to gravel sized clastic fragments of
red siltstone, metamorphics and basalt were observed at the base, and subsequently, beds became
well sorted towards the top. Said fragments commonly found at the base of beds were
infrequently present at the top, highlighting beds were locally overturned (L15.11-
GPS:599936,100914) (Fig.13). This marl unlike others was harder and more brittle in fresh
surface, although no clear cement was apparent in the field.
3.3.2-Cerro-Gallardo-Volcaniclastic-Formation
This formation had an erosional onlapping contact with the lower the AMf. In regions the CGVf
(Cerro-Gallardo-Volcaniclastic-Formation) sat directly on the youngest basement (ERSf/BDLf)
with an erosive nonconformable contact (L15.18-GPS:601307,101543), in areas where the AMf
had been eroded away. The 336m thick CGVf, covered the majority of the area to the south of
the CFZ, making up the rugged and ridged Cerro-Gallardo-Hills. The somewhat mountainous
topography commonly exposed almost fresh bedrock, although much of this formation was
covered with vegetation due to the weathering and subsequent generation of nutrient rich
volcanic soils. The CGVf, was made up of four members, as seen in Table.2.
Table 2. Depicting the observations of the four members making up the Cerro Gallardo Volcaniclastic Formation
Member Observations
Block Ash
Breccia
Member
- Highly angular clasts (Fig.11B)
- Poorly sorted
- Undifferentiated brecciated volcanic clasts of andesite and dacite
- Clasts embedded in a fine leucocratic ash matrix
- <75% matrix
- Formed unconformable and conformable contacts with Tufaceous Breccia
Member
- Contained Imbricated clasts with a north north-easterly paleocurrent
direction.
Tufaceous
Breccia
Member
- Clasts embedded in a fine leucocratic ash matrix
- Hornblende embedded within the ash (Fig.11D)
- Poorly sorted
- Mesocratic clasts had with silica content
- Infrequently showed a laminated structure (Fig.11A)
- <75% matrix
Andesitic
Breccia
Member
- Highly angular clasts
- Mesocratic clasts had with silica content - andesite
- Grey coloured ash matrix
- Poorly sorted
- Brecciated volcanic clasts of andesite
Granitilla
Moros
Agglomerate
Member
- Clast supported
- Poorly sorted
- Clast size ranging from 10cm-1m in diameter (Fig.11C)
- Sub angular to sub rounded
- Undifferentiated volcanic clasts
- White ash matrix was seen filling the pore spaces

pg. 18
3.3.3-El-Ciscarico-Red-Breccia-Formation
The CRBf (El-Ciscarico-Red-Breccia-Formation), made up the highest stratigraphic unit of the
southern sequence and was identified as purely sedimentary facies in the field. The formation
was 146m thick, often capped hilled regions to the south of the area and was separated from the
CGVf by a prominent angular unconformity well exposed (L6.20-GPS:595308,097851). Fresh
surfaces of this formation outcropped throughout the area, with minimal amount of weathering.
This alongside the characteristic red matrix, made its easy to identify.
5cm 7cm
3m 4cm
40cm 1cm
A B
C D
A B
Figure 11. Field photographs of A – laminated white ashes recorded at L28.5-GPS:601742,101834. B – block ash
breccias recorded at L14.5-GPS:600602,100599. C – coarse rounded agglomerates recorded at L14.19-
GPS:600473,100769. D – hornblende crystals embedded in white ash recorded at L6.1-GPS:595362,097939.
Figure 12. Lithological images. A – field photograph of well exposed CRBf recorded at L8.22-GPS:598119,098572. B –
photograph of petrographic slide (TS5-GPS:600234,100497) showing iron stained rim of hornblende crystal.

pg. 19
The CRBf consisted of sub-rounded to sub-angular eroded clasts, made up of both leucocratic
ash and undifferentiated clast supported andesitic and dacitic volcanic fragments. Oxidation of
hornblende minerals in volcanic clasts was apparent, in form of iron stained rims. Finally, the
red oxidised matrix often contained abundant disarticulated fragments of shelled shallow marine
fauna.
3.3.4-VOLCANIC STRUCTURE
The volcanic sequence of Langhian-Burdigalian age (AMf & CGVf), formed a large-scale
syncline with a north-westerly dipping axial surface. The northern limb of the fold was often
steeply inclined (Fig.13) parallel to the CFZ and locally overturned meaning the mapped units
outcropped as linear features. The southern limb on the other hand was very shallowly dipping
to the northwest (Fig.13) meaning mapped units often followed the contours as sinuous mapped
features. The relationship between the CGVf and the AMf was somewhat complicated, as the
younger units appeared to be crosscut by the AMf (GPS:600500,1010250), although field
observations showed the lower AMf to be older due to the fining sequence seen. The structural
data recorded in the CRBf, showed a clearly different trend to that of the folded CGVf, showing
this formation unconformably overlay the CGVf.
3.4-SEDIMENT
3.4.1-Saltado-Formation:
The Sf (Saltador-Formation) was the lowest stratigraphic unit to the north of the CFZ,
comparable in age to the CRBf of the southern sequence. Similarly to the AMf, this formation
was heavily affected by weathering to the extent where grey residual soils were seen to cover
most exposures. The formation was recorded to be 101m thick, being made up of two members.
The 27m thick lower RPm (Ricon-Perido-Calcerous-Siltstone-Member) and the 74m thick SAm
Figure 13. Trend of data recorded
throughout the volcanic sequence to
the south of the Carboneras Fault
Zone.

pg. 20
(Saltador-Argillaceous-Marl-Member), both outcrop around El-Saltador. The Sf sat non-
conformably on all of the basement rocks at differing locations through the area, however, the
contact between the two members was conformable. This meant the upper member (SAm),
locally non-conformably contacted the basement (GPS:597000,099500) but more regionally
conformably contacted the lower RPm.
The SAm, was characterised by its grey/yellow colouration in both weathered and fresh surfaces
and by the fining upward bodies of lithic-arenite (Fig.14A). The lithic-arenite horizons were
made up of fragments of basement rock and Neogene sediments, the compositional abundances
are as listed and depicted in Fig.14B. The grey colouration was attributed to the higher
abundance of clastic material, compared to other marls seen throughout the area. The
distinguishable characteristics of the RPm were its coarser grainsize, higher clastic content,
absence of fining-upward sandstone horizons and abundance of predominantly horizontal
burrows (Fig.14A/C). Despite the RPm’s distinct lithological and textural differences, its small
scale and conformable contact with the SAm allowed the two to be grouped into one formation.
3.4.2-Corjill- Portillo-Sandstone-Formation
The 54.5m thick CPSf (Corjillo-Portillo-Sandstone-Formation), dis-conformably overlay the Sf
and infrequently non-conformably overlay basement rock (Fig.16A). The unit outcropped to the
southwest of the mapping area, often well exposed by road cuttings along the ALP-711 (L1.1-
A B
C
Figure 14. Showing the observation of the Saltador Formation. A – showing
sedimentary log of unit recorded at L17.2-GPS:595092,0987507. B – showing
provenance grain abundances of sample. C – showing horizontal burrows
that were often seen recorded at L6.13-GPS:595623,098753. All produced in
CorelDraw. For pie chart colour scheme and log key see Appendix F.

pg. 21
GPS:594425,098483). Weathered surfaces of this formation were often discoloured and weaker
than the fresh surfaces, however, sedimentary structures and fabrics were undisturbed.
Distinctive members of the CPSf weren’t explicitly noted in the field, however, differing facies
were present throughout this formation from later reviewing field observations. The observations
independent to each facies are denoted below (Tab.3).
Table 3.Depicting the four sub facies included within the Corjillo Portillo Sandstone Formation
Facies Observation
I
Bioclastic Calc-
lithicarenite
- High abundance of bivalve, oyster and unidentifiable allochems - ranging in size
from <1mm-15cm (Fig.16B)
- preservation of allochems growth structure (Fig.17E)
- Variable grainsize from fine to very coarse sand.
- For compositional mineral abundances see Fig.15A.
- poorly sorted due to large allochems
II
Homogenous
Calc-
lithicarenite
- Rare shell remains
- Commonly medium sand grainsize
- Secondary fabric (Identified post mapping from collected photographs)
- Laterally continuous - large tabular unit
- Highly porous (Fig.17A/B)
- For compositional mineral abundances see Fig.15C
- Colouration changes defining bedding horizons
III
Gravel Calc-
lithicarenite
- Poorly sorted
- Abundant gravel size fragments - often eroded out of medium grained ground mass
(Fig.16C).
- For compositional mineral abundances see Fig.15B.
IV
Laminated marl
- Fine, silt to mud grainsize
- White in colour
- Well sorted
- laminated 25cm thick bed outcropping at L17.3-GPS:594935,099100
A B C
Figure 15. Showing different provenance compositional abundance of differing facies. A - Bioclastic Calc-lithicarenite. B - Gravel
Calc-lithicarenite. C - Homogenous Calc-lithicarenite. For pie chart colour scheme see Appendix F.

pg. 22
Petrographic analysis showed facies I & II, were clast supported and cemented by sparry calcium
carbonate. Surrounding grains small crystals with a slightly darker colouration showed the first
phase of cementation (Fig.17C), although petrographic resolution didn’t allow this to be fully
analysed. Finer sparry crystals then filled the voids between clasts and frequently graded into a
coarse sparry mosaic texture (Fig.17D). The siliciclastic content was predominantly quartz with
very low abundances of plagioclase feldspar.
3.4.3-Garcia-Marl-Formation
The 62m thick GMf (Garcia-Marl-Formation) outcropped in the same geographical area as the
CPSf. The formation was seen to cross crosscut the CPSf (GPS:574750,098750), defining the
1m 4m 4m
A B C
A B C
D E
Figure 16. Showing field pictues of the CPSf. A – showing lower erosional contact with schist recorded at L16.2-GPS:594164,098904. B – showing
articulated mollusc shell fragment recorded at L1.23-GPS:594428,098420. C – showing eroded gravel clasts out of unit recorded at L1.10-
GPS:594750,098483.
Figure 17. Depicting thin section photographs of A-C showing TS1-GPS:594164,098929. D-E showing fossiliferous unit of S3-
GPS:590556,097253.
PPL | XPL PPL | XPL PPL | XPL
XPL XPL

pg. 23
unconformable contact between the two. This unit again displayed characteristic weathering of
marl in the area, covering the bedrock with residual soils distorting all lithological structures.
The defining characteristic of this marl was its clear white colouration in weathered surface.
Although few fresh surfaces of this formation were observed, road cut sections along the ALP-
711 allowed this formation to be studied in detail.
The majority of this formation was made up of fine, well sorted, white, infrequently laminated
marls with a clastic content of »50%. Small white shell fragments and red coloured elongate
microfossils were observed in the field, confirmed to be benthic foraminifera following
petrographic analysis (Fig.18C). Brecciated units were present throughout the formation ranging
from 15-50cm in thickness and were laterally discontinuous diminishing in thickness towards
the SSW (Fig.18A). The brecciated horizons compositional abundances are denoted in Fig.18B,
the lower of the two contained imbricated clasts with a southward paleocurrent direction and
both showed no evidence of being graded.
3.4.4-Molata-Blanca-Formation
The Molata-Blanca-Formation, denoted in the field, was interpreted to be made up of three
members. However, sufficient distinguishable lithological characteristics on a 1:10,000
mappable scale, meant field data has been reinterpreted. Henceforth, hierarchical component of
A
B
C
Figure 18. A - showing graphic log of GMf recorded at L16.3-GPS:594224,098855. B – showing provenance clast abundance of the two debrite
deposits. C – showing benthic foraminifera included in marl horizons of TS2-GPS:595082,098892. Digitised using CorelDraw. For pie chart
colour scheme and log key see Appendix F.
PPL | XPL

pg. 24
its Aguila-Marl-Member, Molata-Gypsum-Member and Broton-Marl-Member have been altered
to formations.
3.4.5-Aguila-Marl-Formation
The 124m thick Af (Aguila-Marl-Formation), flanked the Molata-Blanca highlands and was
characterised extensive erosive topography where extensive incision of gullies formed badlands.
Badlands were commonly composed of white residual soils where all structures were destroyed.
The base of the formation formed an angular unconformable contact with the underlying
sediment sequence and a nonconformable contact with the HAf (GPS:593450,097250). The
formation was characterised by three lithofacies with occurred in interbedded triplets as depicted
below (Fig.19A & Tab.4).
Table 4. Depicting the three facies making up the cyclical sediments of the Aguila Marl Formation.
Facies Observation Petrographic Observation
I
Organic marl
(Sapropel)
- Dark in colour
- Organic rich
- Soil like texture
- Highly incohesive
- Heavily effected by erosion
- Tabular beds
- N/A
A B
C
Figure 19. A – showing graphic log with cyclical nature of the Aguila Marl Formation recorded at L17.1-
GPS:594158,098602. B – showing mineralogy of hardened marl recorded at S11-GPS: 594158,098602. C -
showing mineralogy of homogenous marl recorded at S11-GPS: 594158,098602. For log key see Appendix F.
PPL | XPL
PPL | XPL

pg. 25
II
Hardened marl
- White in colour
- Heavily and sharply fractured
- Brittle
- Tabular beds
- More resistant to erosion
- Abundant benthic
foraminifera
- Approximately 30% clastic
content
- see Fig.19B
III
Soft homogenous marl
- White/ pale yellow in colour
- Frequently homogenous
- Very incohesive
- Infrequently contained
disarticulated and fully fragmented
shell fragments.
- Laminated in areas
- Often eroded to residual soil
- Infrequently contains very
fine undifferentiated
Allochems
- Approximately 30% clastic
content
- See Fig19C
3.4.6-Molata-Gypsum-Formation
The 74.5m thick MGf (Molata-Gypsum-Formation), forming a prominent ridge more resistant
to erosion, conformably overlay the badlands of the Af. Majority of the exposures were lightly
weathered, however, the steep nature of the ridge made accessing good exposures impossible.
The formation was characterised by presence of crystalline gypsum which ranged in size from
<1cm-10cm. The formation was visited outside of the mapping area (L29.10-
GPS:591142,97553), where a cyclic nature of the formation was observed, with gypsum being
interbedded with laminated pelitic sediments. Gypsum horizons, were commonly crystalline,
forming both arrow-headed crystals (Fig.20B) and large cauliflower structures but infrequently
occurred as mixtures of sediment and gypsum crystals. Soft sediment deformation was apparent
in pelitic sediment (Fig.20A), beneath gypsum beds, where laminae were clearly convolute.
2cm
A
B
Figure 20. A – showing graphic log with cyclical nature of
the MGf. B – showing picture of sample showing arrow
head gypsum growth. Both recorded at L29.10-
GPS:591142,097553 and digitised using CorelDraw.
convolute. For log key see Appendix F.

pg. 26
3.4.7-Broton-Marl-Formation
The BMf (Broton-Marl-Formation) conformably contacted the MGf seeing the loss of gypsum
horizons. The 80m thick formation, capped the Molata-Blanca highlands and was heavily
vegetated, with infrequent vertical outcrops of bed rock.
The conformable contact with the lower MGf, was characterised by weathered dark horizons
within the mapped area, interpreted to be a silt horizon. However, the same contact traced into
the Níjar Basin (out of mapping area), where a sample was collected and cut for petrographic
analysis. The dark horizon was identified as a fine volcanic ash layer which was coupled with
multiple black features showing a fractal pattern (Fig.21A). These features were identified as
dendritic growths post mapping from field photographs. The rest of this formation was typified
by white to yellow, well sorted, mud sized, laminated marls (Fig.21B) with little to no variation
from this lithofacies.
3.4.8-Barranco-Sandstone-Formation
The BSf (Barranco-Sandstone-Formation) made up the youngest stratigraphic unit, 41m in
thickness. The contact with the lower stratigraphic units (Af, MGf and BMf) was a clear
angular unconformity where inclined beds of the lower formations were crosscut by bedding
of the BSf. The formation made up the most westerly proportion of the mapping area to the
west of the Molata-Blanca highlands.
The formation coarsened upwards, as seen in Fig.22A. The formation was predominantly fine
to medium in grainsize containing a heterolithic lithofacies of interbedded sand and silt. The
formation was much more texturally mature than the CPSf, although both were calcareous
lithic-arenites, as this formation contained less lithic fragments of basement rock and higher
A
B
Figure 21. Showing field pictures of BMf, A – showing dendritic growths at GPS:596590,097321 and B –
showing white fine-grained laminae recorded at L10.24-GPS:593602,098132.

pg. 27
proportions of fine weathered siliciclastic material and fragments of younger strata (Fig.22B).
The formation contained shallow marine fauna, where whole echinoids and their spines
(Fig.22C), shell fragments and burrows were observed in abundance. Symmetrical ripples,
cross bedding and laminations showed the variability of this formations structure.
3.4.9-Sedimentary Structure
The Tortonian strata, comprising the Sf, the CPSf and the GMf, formed a folded sequence of
tight upright folds. Folds had wavelengths of »200m, with an 076o
oriented axial surface,
aligned with a weak cleavage within the CPSf which formed as a result of alignment of platy
metamorphic fragments (Fig.23A). The Tortonain fold structure was more complicated due to
the unconformable sediment packages making up this fold. The above Messinian strata made up
of the Af, MGf and BMf formed open upright folds. Folding was less prominent compared to the
Tortonian sequence, with a slightly differing trend where the axial-surface had rotated
anticlockwise to 063o
. The trend of bedding data of the BSf, again showed a fold although the
axial surface wasn’t seen in area, interpretations of the structural data (Fig.23B) showed the
axial-surface of this fold sequence had again rotated anticlockwise to 037o
. The entirety of the
stratigraphic sequence both plunged and thickening towards the southwest.
A B
C
Figure 22. Showing field observations of BSf. A – showing composite log
recorded at L16.1-GPS:593303,097525. B – showing clast mineralogy
abundances recorded using S9-GPS:593303,097536. C – whole echinoid
fragment observed at L16.1-GPS:593303,097525. Digitised using CorelDraw.
For pie chart colour scheme and log key see Appendix F.

pg. 28
3.5-FAULT ROCKS
3.5.1-Colada-Gauge-Formation
The CGf (Colada-Gauge-Formation) outcropped as anastomosing features with a NE-SW trend,
varying in thickness from 1m-50m. The fault strands were most frequently present in the CMSf
through the centre of the mapped area, running parallel to some fluvial channels. Fault gauges
were often heavily weathered to the extent that no structural data could be obtained, due to the
fine incohesive nature of the fault rock. Three distinctive gauge facies were observed as outlined
in Tab.5.
Table 5. Depicting the three different characteristic fault gauges making up the Carboneras Gauge Formation.
Facies Observation
I
Banded
gauge
(See Fig.24A)
- contained highly deformed fault bound horizons of:
- Red Siltstone (ERSf)
- Phyllite (LGf)
- Psammite (LGf)
- Graphite Schist (CMSf)
- Marl (Sf)
- Dolomite (BDLf)
- Tectonised Gypsum (MGf)
- Contained elongate sediment fragments showing left lateral displacement.
- Contained sub-horizontal striated dolomitic surfaces showing left-lateral displacements.
- Striations » parallel to strike of faults (Fig.24C)
II
Homogenous
sediment
gauge
- Un-banded
- homogenous
- Sediment rich, containing fragments of lithic arenite and argillaceous marl (Fig.24B)
- Almost entirely made up of Sf
- Traces of relict bedding of Sf strata
A
B
Figure 23. Showing the structure of the
northern sedimentary sequence. A –
showing minor alignment of platey minerals
forming slight cleavage recorded at L1.1-
GPS:594425,098483. B – showing trend of
bedding data throughout the sequence, see
key for info.

pg. 29
The faults associated with the formation of the CGf were also responsible for the cataclastic
damage of the bed rock to either side fault gauge strands. Within these damage zones structural
features of the formations were often completely destroyed.
3.5.1.a-Structure
The structure of the CGf was defined by the vertical to sub vertical fault bound gauge contacts,
which showed faults both steeply dipped to the northwest and to the southeast (Fig.25C). The
faults became more shallowly dipping to the northwest in the north of the area. The liniations
- Traced out following faulted contact with packages of Sediment
III
Foliated
gauge
- Foliated
- Dark grey in colour.
- Few clastic fragments
Had complex shearing structure
- Rarely contained powdered quartz fragments showing no structure.
5m
m
A
B C
Figure 24. Showing field observation of CGf. A – showing banded nature of gauges recorded at L25.13-GPS:599882,101043. B –
showing sediment rich gauge with relict bedding recorded at L21.25-GPS:599497,101090. C – showing strated dolomite surface
showing movement parallel to strike of fault recorded at L12.15-GPS:595932,098789.

pg. 30
recoded on more brittle fault surfaces showed movements of the fault zone were predominantly
left lateral with a reasonable spread of data showing both transpressive and transtensional
geometries (Fig.25C). Where the formation was best exposed, gauge derived from both mica-
schist and sediment, showed clear structure. A left lateral foliation was the most prominent
structure (Fig.25B), defined by the elongation and asymmetries of rigid marl fragments. More
interestingly R1 shears displaying left-lateral displacements and X shears displaying right-lateral
displacements (Fig.25A), were present in this formation (L26.21-GPS:600301,101990).
6cm
C
A B
Figure 25. Structural observations of CGf, A – showing R1 shears showing left lateral displacements. X shears
showing right lateral displacements. B – showing zoomed in left lateral P shears / foliation. A-B recorded at L26.21-
GPS:600301,101990. C – depicting trend of faults and slip liniations parallel to said faults. Digitised using
CorelDraw.

pg. 31
3.6-INTRUSIVES
3.6.1-Hoya-Andesite-Formation
The HAf (Hoya-Andesite-Formation), forming linear features throughout the area, intruded into
the basement rocks and into the Sf (GPS:596900,099500). To the north and south of the area the
intrusion thickened and was nonconformally overlain by the Af as noted earlier. The formation
was often heavily weathered and discoloured to a brown soil like consistency, however the
mineralogy was not fully destroyed.
In fresh surface the formation was grey in colour and contained obviously fibrous, hexagonally
shaped hornblende crystals and also contained plagioclase feldspar in abundance. Petrographic
analysis showed the mineralogy of the dyke (TS12-GPS:600076,101002) and the large intrusive
bodies (GPS:593505,097156 & GPS:593738,097513), as outlined below (Fig.26), to be
intermediate in composition with characteristics of both andesite and dacite. However, the low
silica content, supports the field classification of andesite.
3.6.1.a-Structure
The orientations of the intrusive bodies throughout the area, as seen in Fig.27, show an average
dyke orientation of »060o
. The orientation and almost vertical nature of the intrusive bodies
make them broadly concordant with the trend of the faults through the area.
A B C
Figure 26. Pie charts showing mineral abundances recorded using thin setions: A - S5-GPS:593738,097513, B - TS12-
GPS:600076,101002 and C - TS4-GPS:593505,097156 showing intermediate andesitic composition. Digitised using CorelDraw.

pg. 32
3.7-QUATERNARY GEOLOGY
The ramblas within the area were thought to be broadly concordant with the orientation of the
fault gauges. The post mapping analysis of rambla orientation, as outlined in chapter 2, gave the
modal orientation of 067o
(Fig.28).
Figure 27. Rose diagram produced in
GeoRose showing trend of HAf dykes
throughout the area. Re-Digitised using
CorelDraw.
Figure 28. Rose diagram produced in
GeoRose showing trend of fluvial channels
throughout the area. Re-Digitised using
CorelDraw.

pg. 33
4.0-DISCUSSION
4.1-BASEMENT INTERPRETATIONS
The CMSf and LGf showed clear evidence of metamorphic alteration, the CMSf had two distinct
lithofacies (Tab.6), showing different textural and mineral characteristics due to differing grades
of metamorphism. The majority of the formation was of upper green schist facies (Kampschuur
and Rondeel, 1975; Lonergan and Platt, 1995), however schists of lower amphibolite facies were
seen in uplifted fault bound regions (Rutter et al.,2012), showing this tectonic complex decreased
in metamorphic grade upwards. The different lithofacies identified correlate with the Nevada
Table 6. Showing the index minerals of each differential metamorphic unit and subsequent facies and zone interpretation
with formal names.
Unit Mineral Abundance Classification Interpretation
FaultBoundCMSf
Index Mineral: Staurolite
Metamorphic Zone: Staurolite Zone
Metamorphic Facies: Lower Amphibolite Facies
Name: Porphyroblastic Staurolite-Chiastolite, Graphitic Mica
Schist
Unconstrained
CMSf
Index Mineral: Biotite
Metamorphic Zone: Biotite Zone
Metamorphic Facies: Upper Green Schist Facies
Name: Biotite-Graphite Mica Schist
LGf(Phyllite
Member)
Index Mineral: Chlorite
Metamorphic Zone: Chlorite Zone
Metamorphic Facies: Lower Green Schist Facies
Name: Chlorite-Mica Phyllite
Formation of the NFC-Bédar-Macel Unit, comprising of graphite mica schists and tectonically
lower staurolite bearing graphite schists (Alonso-Chaves et al., 2004; Kampschuur, 1975). The
graphitic nature and presence of schistose cutting pyrite minerals show exhumation wasn’t rapid
as retrograde alterations were allowed to occur (Craig and Vokes, 1993). The relict S0 bedding
of psammite, pelite and graphite, seen within the Sierra-Cabrera highlands and the presence of
pyrite, chiastolite and staurolite, indicate the protolithic sediments were organic rich muds, sands
and carbonate rocks, deposited in an anoxic environment (Deer et al., 1996).
The LGf underwent a similar tectonic evolution to the CMSf, and again had a pelitic and
psammitic protolith evidenced from the relict interbedding of psammite. The formation was of
lower grade then the CMSf, being of lower green-schist facies (Rutter et al., 2012), corresponding
to the formally known Phyllite-Formation of the AC, which often contains quartzites in its upper
section (Alonso-Chaves et al., 2004; Kampschuur, 1975). Both units later underwent regional
Barrovian metamorphic alteration as a result of the Betic-Rif Orogeny (Zeck, 1996), showing

pg. 34
deeper units were more heavily metamorphosed due to exposure to higher pressures and
temperatures (Fig.29).
The ERSf, containing red stained, silt-fine sand fragments, was void of any fossils and showed
relict traces of laminae and bedding. This evidence indicated the formation was deposited in a
marine environment during a warm and dry Permo-Triassic period (Sheldon, 2005). This unit is
inferred to be a part of the Permo-Triassic Redbeds of the MC (Rutter et al., 2012; Lonergan,
1993). The faint mineral alignments showed this formation was slightly deformed during the
Betic-Rif Orogeny (Zeck, 1996), although no mineral recrystallisation occurred. The BDLf made
up the highest tectonic slice, where relict limestone textures and shells, indicate this formation
was deposited in a shallow marine environment. Where this unit was completely black, it was
difficult to interpret much about the paleoenvironment of deposition. The presence of dolomite
indicated that post deposition of limestone, sea waters sufﬁciently rich in Mg (Land, 1985;
Machel and Mountjoy, 1986), caused widespread dolomitization in semiarid climatic conditions
in a shallow water environment with restricted circulation and high evaporation rate (Gasparrini,
2003). The intense dolomitization increased the hardness and brittleness of this unit allowing
movements of the CFZ to fracture this unit (Rutter et al., 2012).
4.2-VOLCANIC INTERPRETATIONS
The lowest unit of this sequence was the AMf which was composed of mainly well sorted fine-
grained marls, indicating this unit was deposited in a marine environment (Serrano, 1990). Clasts
of basement rocks showed how this unit followed a period of erosion of the basement sequence.
Gravel size clasts of a basaltic composition show how unevolved magmas were ripped off walls
of igneous conduits early on in the volcanic evolution (Rutter et al., 2012). The units more brittle
Figure 29. Graphical pressure-temperature-time graph showing the likelt evolutionary path
the LGf, high grade CMSf and the low Grade CMSf took. Adapted from Winter (2010).

pg. 35
character compared to normal marls, show how movements along the CFZ have pressurised this
rock causing minor tectonic alterations (Rutter et al., 2012).
The CGVf stratigraphically above, comprising block ash breccias, tuffaceous breccias, and
andesitic magmas show how volcanic centres of the Cabo de Gata (Soriano, 2016), often
collapsed releasing pyroclastic block ash breccias into a marine environment. Hemipelagic
settling of fine leucocratic ash (Fig.11A), also support the notion that these were deposited in a
marine island arc environment. The variance of the silica content of brecciated clasts show how
lava domes recharged with varying compositional melts (Beccaluva et al., 2011). The
intermediate andesitic/dacitic composition of the CGVf /HAf, indicate that decompressional
partial melting and asthenospheric upwelling (Scotney, 2000; Turner, 1999), fuelled the regional
volcanism.
The CRBf, a massive volcaniclastic breccia with a red micritic matrix (Rutter et al., 2012; Uwe,
2003), capped this sequence and contained sub-angular to sub-rounded clasts of the CGVf. These
clasts were sourced from the sub-aereal erosion of the CGVf (Franseen et al., 1993), as a result
of transpressive uplift of the CFZ (Serrano, 1990), leading to increased rates of erosion. The
incorporation of the eroded material occurred due to a marine inundation (Franseen et al., 1993),
where a moderate energy shallow-marine environment was established.
4.3-SEDIMETARY INTERPRETATIONS
The lowest stratigraphic sedimentary unit was deposited following a long period of erosion
during the Betic-Rif orogenesis. The earliest sediments deposited were calcareous siltstones
(RPm) with a sandy bottom region (Rutter et al., 2012) rich in horizontal burrows deposited in
paleo-lows as base level rose. Further base level transgression lead to the deposition argillaceous
marls (SAMm), showing the unit was sourced from fluvial siliciclastics and marine carbonates.
This alongside the fine mud-silt grain size, show the early Tortonian was characterised
hemipelagic settling of clastic and carbonate material in a distal marine environment (Fortuin
and Krijgsman, 2003; Van de Poel, 1992). Classic fining upwards bodies of calc-lithic-arenites
were observed with differing trending clast provenance than the younger sediments, indicating
this unit had a differing source. The deposition of these sand horizons is a result of submarine
waning turbidity currents.
Uncomfortable deposition of the CPSf, showed a major regional scale base level regression,
tracing into the Vera Basin (Booth-Rea et al., 2004) seeing it sit non-conformably on basement
rock. This unit’s high abundance of basement fragments, minimal siliciclastic content, high
abundance of shallow marine bivalve and clam remains; coupled with the coarse, angular, poorly
sorted material forming symmetrical ripples, indicate these were deposited in a shallow marine
littoral beach environment (Braga et al., 2006; Huibregtse et al., 1998). The two-phase
cementation shows these were subject to high wave energy’s forcing marine waters into pore
spaces forming early bladed prismatic cements with later deep burial formation of sparry mosaic
cements (Enge, 2002). The CPSf corresponds to the lower section of the Azagador Member of
the Turre Formation (Volk and Rondeel, 1964), which grades into a marl rich facies. The
findings of the report instead show a locally unconformable contact forming another distinct
formation (GMf), due the transpressive uplift of the CFZ and uplift of the Sierra-Cabrera. The
GMf characterised by white marls rich in benthic foraminifera and infrequent debrite deposits,
indicating the paleoenvironment of deposition was a proximal marine environment in a warm
dry climate where fluvial systems were less active.

pg. 36
The three formations of Messinian age (Af, MGf, BMf), formed a conformable package of
sediment. The lower Af comprising hard marls, soft marls and organic marls had a cyclical
nature. The statistical analysis of these cycles as described in Chapter 2, show interplay a
17554yr cycle and to a lesser extent a 38462yr cycle, relating to precession and obliquity
respectively, both of which being very unlikely to be random due to high false alarm probability
spikes (Fig.30). The 10 cycles within the Af (Fig.19A), trace the migration of the monsoon belt
up and down Africa where reduced fluvial input led to the deposition of purer carbonate units
and ultimately organic rich sapropel units, when ocean stagnated and become anoxic at depth
(Krijgsman, 2001; Sierro et al., 1999). The upper MGf, made up of thick crystalline gypsum
beds, traces the closure of the Gibraltar-Arc and the initiation of the hypersaline environment of
the Messinian Salinity Crisis (Pagnier, 1976; Van de Poel, 1991). This unit again has
astronomically controlled cycles, although no statistical analysis was undertaken to determine
the wavelengths of said cycles. The upper BMf made up of white well bedded marls was
separated from the MGf by a dark ash layer responsible for the leaching of Mn into the lower
marls forming dark dendritic manganese concretions (Rutter et al., 2012), showing volcanic
activity continued into the Messinian. The upper unit saw the loss of gypsum horizons tracing
the reflooding of the Mediterranean Basin and the establishment of normal marine salinities
(Duggen et al., 2003).
Figure 30. Graph showing lomb scargle power spectrum showing frequency of cycles within the Af.
And the lower False alarm probability. Produced using MATLAB.

pg. 37
Capping the northern sedimentary sequence were yellow coloured fine calc-lithic-arenites of the
BSf, rich in shallow marine fauna and symmetrical ripples (Blum, 2007). The formation
coarsened upwards showing a general base level regression leading to the current terrestrial
setting (Rutter et al., 2012), where clasts were well sorted and contained more siliciclastics
indicating they had undergone a higher degree of erosion and transport than the CPSf. The upper
part of this formation contained symmetrical ripples of shallow marine origin and larger scale
cross beds, formed as a result of large storm events in a shallow sea (Dabrio, 1986).
4.4-COMPARISON TO LITERATURE
Table 7.Depicting the variance of this study’s observations from those of the published literature.
This Studies
Formations
& Thickness
Equivalent
Published
Formations
Literature Comparison
B
A
S
E
M
E
N
T
Cortijada el
Marques
Graphite
Mica Schist
Formation
Nevado Filabride
Complex
Nevada Formation
of the Bédar-Macel
Unit
(Kampschuur,1975).
Similarity - Outcrop of higher-grade schists within fault
bound regions of the CFZ (Rutter et al., 2012).
- Migmatic alteration in fault bound areas of the
CFZ (Rutter et al., 2012).
Difference
- Higher grade than generalised upper
greenschist facies of literature (Kampschuur
and Rondeel, 1975; Lonergan and Platt, 1995).
- No sillimanite found in thin section unlike
literature (Rutter et al., 2012).
La Granitilla
Formation
Alpujarride
Complex
Phyllite Formation
(Alonso-Chaves et
al., 2004)
Similarity
- Lower green schist facies identification in
chlorite zone (Rutter et al., 2012).
- Quartzites in its upper section (Alonso-Chaves
et al., 2004; Kampschuur, 1975).
Las Escalicas
Red Siltstone
Formation
Red Beds of
Malaguide Complex
Similarity
- Same identification as red beds of silt to sand
size (Rutter et al., 2012; Lonergan, 1993).
Berenes
Dolomitic
Limestone
Formation
Dolomites of upper
Malaguide Complex
Similarity
- Black colouration and identification as
dolomite (Alonso-Chaves et al., 2004).
- Very heavily fractured (Rutter et al., 2012).
- Caps upland areas (Garcia et al., 1974).
V
O
L
C
A
N
I
C
S
Algarrobico
Marl
Formation
(47m)
Burdiglian Marls -
not formally named
(Rutter et al., 2012)
(40m)
Similarity
- Mix of clastic and carbonate fine grained
sediment (Serrano, 1990).
- Hardened state in thin section, interpreted as
tectonised by Rutter et al (2012).
Difference
- 7m differing thickness
- Inclusion of ERSf and LGf fragments.
- Identification of basalt rather than gabbro like
Rutter et al (2012).
Cerro
Gallardo
Volcaniclastic
Formation
Older Volcaniclastic
Sequence
(322m)
Similarity
- Presence of agglomerated, block ash breccias
and tuffaceous breccias (Rutter et al., 2012).

pg. 38
(336m)
Difference
- no identification of lahars or sandstone bodies
like Rutter et al (2012).
- thickness difference of 24m
El Ciscarico
Red Breccia
Formation
(146m)
Brèche Rouge
(Krautworst &
Brachert, 2003)
(»100m)
Similarity
- Identification of micritic mud matrix (Uwe,
2003).
- Identification of shallow marine fauna (Uwe,
2003).
- Presence of a highly angular erosive lower
contact (Rutter et al., 2012; Uwe, 2003)
Difference
- 46m thickness difference
S
E
D
I
M
E
N
T
A
R
Y
Saltador
Formation
(101m)
Saltador Formation
Named by - (Van de
Poel 1992)
Thickness from -
(Rutter et al.,2012)
(75m)
Similarity
- Unconformable lower contact (Rutter et al.,
2012).
- Inclusion of hemipelagic marls and turbiditic
sandstone bodies (Valetti et al., 2019).
Difference
- Identified of a lower calcareous siltstone
member in comparison to other papers.
- 26m thickness difference, likely due to sole
reliance on structural data rather than seismic.
Corjillo
Portillo
Sandstone
Formation
(54.5m)
Turre Formation -
Lower Azagador
Member
Named by - (Volk
and Rondeel, 1964)
Thickness from -
(31m)
Similarity
- This study’s facies: I (Bioclastic Calc-
lithicarenite), II (Homogenous Calc-
lithicarenite), III (Gravel Calc-lithicarenite) and
IV (Laminated marl) correspond to facies: F11
(Matrix supported bioclastic medium grained
sandstone), F8 (Homogenous sandy calcarenite),
F5 (Massive, pebbly and granular to parallel-
laminated, medium-grained calcarenite) and F9
(Laminated micrite) of Enge’s (2002)
(Table3.1).
- Two phased cement forming blades around
clasts and grading into sparry mosaic cement
(Enge, 2002).
Difference
- Unconformable upper contact with GMf,
doesn’t grade into marl facies as hypothesised by
Rutter et al (2012).
Garcia Marl
Formation
(62m)
Turre Formation -
Upper Azagador
Member
Named by - (Volk
and Rondeel, 1964)
Thickness from -
(104m)
Similarity
N/A - not well documented
Difference
- 42m thickness variation

pg. 39
Aguila Marl
Formation
(124m)
Turre Formation -
Abad Member
Named by - (Volk
and Rondeel, 1964)
Thickness from -
(Braga et al., 2006)
(265m)
Similarity
- The lithological and procession induced
cyclical character of this formation was
concordant with published findings (Sierro et al.,
2001).
Difference
- Unconformable lower contact seeing local
unconformity compared to normal regional
conformable contact (Fortuin and Krijgsman,
2003).
- 141m thickness variation
Molata
Gypsum
Formation
(74.5m)
Yesares Formation
(Braga et al.,2006)
(130m)
Similarity
- Identification of a conformable transition into
this unit from the lower Aguila Marl / Abad marl
(Formally known) (Fortuin et al., 2000).
- Lithological observations and the cyclical
nature of this formation mirrored published
findings (Fortuin and Krijgsman,2003).Difference
- Differing thickness by 50.5m.
Broton Marl
Formation
(80m)
Feos Formation
(Fortuin and
Krijgsman,2003)
(100m)
Similarity
- Presence of dark dendritic concretions forming
Mn rich lower section (Rutter et al., 2012).
-White laminated well bedded character (Rutter
et al., 2012).
Difference
- Identified as conformably overlying Molata
Gypsum Formation however in literature
vigorous erosion and canyon cutting in the
Yesares Formation leading to a regionally
unconformable contact (Fortuin and Krijgsman,
2003).
- Ash layer sourcing the dendritic growth.
- The lithological variation of this unit observed
by some researchers (Fortuin and Krijgsman,
2003) wasn’t apparent within the study area.
- 20m differing thickness.
Barranco
Sandstone
Formation
(41m)
Cuevas Formation
(Addicott et
al.,1978)
(23m)
Similarity
- Calc-lithic-arenites containing shells,
echinoids and echinoid spines (Blum, 2007).
- Presence of planar cross bedding (Dabrio,
1986).
-Unconformable lower contact (Rutter et al.,
2012).
Difference
- Oyster and coralline algae weren’t observed as
Blum (2007) found.
- 18m thickness variation.

pg. 40
4.5-STRUCTURE, TIMING AND KINEMATICS
Figure 31. Subsurface cross-sectional interpretation along lines outlined on the
accompanying A0 map poster.

pg. 41
4.5.1-BASEMENT
The basement rocks formed a three-layered fault bound stack, descending in metamorphic grade
upwards (Platt et al., 2003; Augier et al, 2005). The LGf sat tectonically above the CMSf, with a
mylonitic contact making up the Betic Movement Zone (Platt and Vissers, 1980), as a result of
extensional collapse of the Betics (Rutter et al., 2012). The CMSf was characterised by a clear
penetrative S1 schistocity, which was seen to be axial planar to S1 tight similar folds in the Sierra-
Cabrera highlands (Fig.6A), which formed during the D1 regional metamorphic alteration of the
unit. The schistocity within the area and the Sierra highlands showed differing trends (Fig.6B),
as within the area it was rotated parallel to the CFZ (Rutter et al., 2012). Evidence of D2 was
apparent in the area where schistocity was folded through a vertical axial-surface, although the
mechanism behind this deformation isn’t certain. To the north of the CFZ, normal faults
decorated with incohesive fault gauges and striations parallel the dips of fault planes were
evident in basement rock, related to the Early and Middle Miocene extensional deformation of
the region (Booth-Rae, 2004). The cleavage of the LGf, showed concordance with the CMSf
schistocity and the trend of the fault showing this unit was likely rotated parallel to the fault,
although no data was collected to confirm this hypothesis. The tectonic outlier by Solpalmo
Village (GPS:599500,101500) was a part of a higher tectonic unit, dropped down due to
transtensional Carboneras fault geometries. This unit was subject to less deformation during the
Betic-Rif Orogeny, as it was tectonically higher and during the Carboneras movements, due to
transtensional geometries, preserving S and Z folds. Finally, the ERSf and BDLf were uplifted to
vertical parallel to the south of the CFZ, forming a north-westerly inclined fold around an
intrusive body, due to the transpressive character of the CFZ (Reicherter, 2014; Serrano, 1990).
4.5.2-VOLCANICS
The AMf and CGVf formed a north-westerly inclined asymmetrical syncline (Rutter et al., 2012),
where similarly to the ERSf and BDLf, the north limb of the fold was inclined to vertical and
infrequently overturned, due to the CFZ’s transpressive character (Reicherter, 2014; Serrano,
1990). The older AMf, seemed to crosscut the younger CGVf (Fig.33A), however this cross-
cutting relationship was only apparent. The younger CGVf unconformably onlapped the lower
AMf (Fig.33B), which following the deformation following movements along the fault zone lead
to the mapped pattern seen to the south of the CFZ. The axial surface of the fold was cut by the
Figure 32. Interpretive sketch of tectonic outlier at GPS:599497,101090,
showing smaller scale asymmetrical folds making regional folds.

pg. 42
southernmost fault-strand showing multiple phases of movement along the CFZ occurred both
folding then cutting the folded sequence.
The concordance between the CFZ strands and the intrusive bodies of the HAf, support the notion
that the CFZ had a transtensional character, allowing subduction related magmas to reach the
surface along fault planes (Rutter et al., 2012).
4.5.3-SEDIMENT
The Tortonian sediemnt (Sf/CPSf/GMf) formed a folded sequence where formations thickened
within the troughs of synforms indicating these sediments were deposited soon after or during
the extensional deformation of the region (Booth-Rae, 2004). Folding resulted from the NNW-
SSE directed shortening from Africa-Eurasia convergence (Zeck, 1996), as faint alignment of
platy basement fragments within the CPSf showed evidence of compression. The upper
Messinian-Pliocene sequence were less intensely folded and showed evidence of the rotation of
the orthogonal stress field as axial-surfaces and therefore sigma-1 rotated in an anticlockwise
fashion (Fig.36A-C). Within tectonic inliers in the centre of antiformal regions (Fig.31-
Section.1), the ERSf/BDLf weren’t folded being only slightly inclined. This indicates that some
of the folding may be related to the syntectonic deposition in extensional horst and graben
features or that the pre-existing normal faults may have reactivated allowing the above units to
fold whilst the lower basement only slightly tilts. Finally, the thicknesses of the sediment
packages were thinner than noted in the literature (Rutter et al., 2012; Braga et al., 2006; Fortuin
and Krijgsman, 2003) and regionally conformable contacts were seen to be unconformable. This
is attributed to the uplift of the Sierra-Cabrera and the transpressive uplift of the CFZ
(Reicherter, 2014; Serrano, 1990; Rutter et al., 2012), reducing accommodation space, thus
increasing the paleoenvironments sensitivity to base-level changes.
4.5.4-THE CARBONERAS FAULT SYSTEM
The CFZ cuts through all of the basement rock and post orogenic sediments. Although the
Frohlich classification indicates the CFZ is almost purely strike slip, field observations of small-
scale flower structures (Fig.31-Section4) and an enclosed strand of lower amphibolite,
porphyroblastic stautolite bearing schists of a lower tectonic origin, show transpressive uplift of
the CFZ. Although this forms a regionally positive flower-structure (Fig.34A), responsible for
forming the boundary of the Nijar Basin (Bell et al., 1997; Boorsma, 1992), transtensional
geometries are also seen making the structure of this flower more complex (Fig.34A). Well
preserved fault gauges show clear foliated and sheared internal structure, which alongside the
Figure 33. A - Interpretive box diagram of structure of volcanic sequence fold explaining the apparent cross cutting relationship of the AMf
and the CGVf seen at the surface. B – showing interpreted pre folding onlapping structure.
A
B

pg. 43
parallel liniations, show movements are left-lateral (Rutter et al., 2012), occurring in the upper
5km of the crust (Rutter and White, 1979). The banding observed many outcrops of the CGf,
represents large displacement boundaries as often the protoliths of adjacent fault gauge bands
aren’t commonly found in close proximity (Logan et al., 1979). The CFZ’s formation is not only
a result of the triaxial stress field acting upon it as the fault wouldn’t have propagated in intact
rock, as per the coulomb criterium (Fig.34B). Thus, the basement of the CMSf, being rich in
phyllosilicates and having a penetrative schistocity parallel to the fault zone, allowed the CFZ
to form (Fig.34B).
4.5.5-TIMING AND KINEMATICS
Tensor stress inversion analysis shows the orthogonal positions of sigma 1-3, showing an NNE-
SSW orientated sigma-1 formed the CFZ. However, the inversion returned with the lowest
Figure 34. A – showing box diagram of regional flower structure, showing transtensional geometries and transpressive geometries along Cross
section 4 (Fig.31). B – showing mohrs circle showing fault have only propagated due to the phyllosilicate schistose basement its cutting through.
.
Figure 35. R.Dihedron stress inversion analysis, produced using win tensor, see key within
figure to understand figure. Top left of figure shows Frohlich classification showing
predominantly wrench tectonics with both trans-pressive and trans-tensile tendencies.
A
B

pg. 44
reliability categorisation (E) out of the 5 bands available (A-E), showing the true position of
sigma-1 may vary from that stated in Fig.35. The incorporation of Tortonian aged Sf into fault
gauges show the main movements occurred soon after the deposition of this formation.
Tortonian slip along the CFZ were appetent as some fault strands were unconformably overlain
by the CRBf and cut by others leading to the uplift and erosion of said formation to the north of
the CFZ, showing multiple phases of Tortonian displacements. Minor displacements occurred
post Messinian where thick veins of gypsum sourced from the MGf were transported via
diffusive mass transfer along fault strands and subsequently recrystalised as tectonised gypsum.
Displacements became less apartment in younger sediments, identified to be a result of the
rotation of the orthogonal stress regime recorded in the anticlockwise rotation of axial-surfaces
and hence sigma-1 (Fig.36), due to the nonlinear subducting hinge. This meant the angle between
sigma-1 and the CFZ became more perpendicular through time, aligning with the auxiliary plane,
preventing displacements from occurring.
4.5.6-QUATERNARY
The concordance of the trend of the CFZ (Fig.35) and the orientation of fluvial tracts (Fig.27),
indicated the fault displacements, occurring in the upper 5km of the crust, forming incohesive
fault gauges which were significantly weaker that the rest of the bedrock. In turn these units
were more readily eroded often forming walls of valleys (Fig.31-Section 2/3).
Figure 36. Diagrammatic depiction of the anticloscwise rotation of the stress field through A - Tortonian, B - Messinain and
C – Pliocene strata. Produced using Corel Draw.
A B C
Trend of CFZ Trend of CFZ Trend of CFZ
Sigma-1Sigma-1Sigma-1

pg. 45
4.6-GEOLOGICAL EVOLUTION
Table 8. Depicting the geological history and sequence of geological events related to the time periods in which they occurred in, with reference to major tectonic movements.
Time Period Ma Geological Event
PERMIAN
251
201
20.4
15.9
13.8
11.6
- Deposition of the protolithic sediment of the Cortijada el Marques Graphite Mica Schist Formation, comprising sandstones,
mudstones and carbonate rocks.
- Deposition of the protolithic sediment of the La Granitilla Formation, comprising pelitic sediments with interbedded sandstone
layers.
- Deposition of the Las Escalicas Red Siltstone Formation in a marine environment, during a hot house climate.
- Deposition of the protolithic limestones of the Berenes Dolomitic Limestone Formation, in a shallow marine environment.
- Dolomitization of limestones from Mg rich seawaters, forming the Berenes Dolomitic Limestone Formation.
TRIASSIC
Northern of the CFZ Southern of the CFZ
NEOGENE
Miocene
Aquitanian
Betic-Rif Orogenesis causing deformation, stacking and metamorphic alteration of Permian and Triassic basement rocks.
Burdigalian
Predominantly extensional deformation of region, localised to the
back arc, forming accommodation space for sedimentary
accumulation (Booth-Rae, 2004), uring general Africa Eurasia
convergence (Vissers, 2012).
- Erosion of Permo-Triassic basement
- Non-conformable deposition of marls in a marine island
arc environment forming the Algarrobico Marl Formation.
Langhian
- Period of erosion and subsequent volcanism lead to the
unconformable onlapping deposition of block ash breccias,
tuffaceous breccias and agglomerates relating to multiple
caldera collapses and volcanic eruptions (Cerro Gallardo
Volcaniclastic Formation).Serravallian
Tortonain
- Erosion of all basement rocks in a sub-aerial environment.
- Base level transgression leading to the non-conformable deposition
of the Ricon Perido Calcerous Siltstone Member.
- Further base level transgression increasing water depths, lowering
the paleo-environments energy, leading to the conformable transition
into more distal marine conditions.

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