The document summarizes information about banded iron formations (BIFs) and ironstones. It discusses the characteristics, classification, occurrences, and origins of BIFs from the Precambrian and ironstones from the Phanerozoic. BIFs formed in various depositional environments, including shallow marine shelves and island arc settings, and have sedimentary, volcanic, and biogenic origins. Ironstones include bog ores, oolitic ores, and others that formed in continental and marine environments through weathering and precipitation processes. Examples of BIFs and ironstones in Egypt are also described.
GEOLOGICAL THERMOMETERS
DEFINITION AND CLASSIFICATION
Proper understanding of origin of mineral deposits and their classification requires the knowledge of formation-temperatures of these deposits. Certain minerals, present over there, give information’s with regard to temperatures of their formations and of the enclosing deposits and they are known as geological thermometers. These geological thermometers may be classed chiefly into the following groups based on their preciseness:
1. The thermometers that record fairly accurately the specific temperature condition of formation of deposits.
2. The thermometers that provide an upper or a lower temperature, above or below which the deposits do not form
3. The thermometers that provide a range of temperature within which the deposits form; and
4. The thermometers that serve as rough indications of temperatures of formation of mineral deposits.
The presence of two or more of less precise geological thermometers in a deposit narrows the range of temperature of formation for the deposits
How can minerals deposits be formed; GEOLOGICAL PROCESSES; Ore Fluids; Ore Forming Processes; Concentrating Processes; Magmatic mineral deposits; Residual mineral deposits ; Placer deposits; Sedimentary mineral deposits; Metamorhogenic mineral deposits; Hydrothermal mineral deposits ; Magmatic Deposits
Cumulate deposits: fractional crystallization processes can concentrate metals (Cr, Fe, PGE, Pt, Ni, Ti, Diamond ))
Pegmatites : late staged crystallization forms pegmatites and many residual elements are concentrated (Li, Ce, Be, Sn, U, Rare Earths (REE), Feldspar, Mica, Gems).
magmatic deposits; Mode of Formation of Magmatic Ores Deposits; Mode of Formation of Orthomagmatic Ores ; Fractional Crystallization (or Crystal fractionation ); Magmatic (or Liquid ) Immiscibility; Simple crystallization without concentration (Dissemination); Segregation of early formed crystals; (Layer Types); Injection of material concentrated elsewhere by differentiation Residual liquid segregation; Residual liquid injection; Immiscible liquid segregation; Immiscible-liquid-injection; Early magmatic deposit; Late magmatic deposit; Types of Magmatic Ore Deposits:Chromite; Fe-Ti (± V) oxides; Ni – Cu – Fe (± Pt) sulfides; Platinum Group Elements (PGEs); REE, and Zr in Carbonatites; Diamond in kimberlites.
GEOLOGICAL THERMOMETERS
DEFINITION AND CLASSIFICATION
Proper understanding of origin of mineral deposits and their classification requires the knowledge of formation-temperatures of these deposits. Certain minerals, present over there, give information’s with regard to temperatures of their formations and of the enclosing deposits and they are known as geological thermometers. These geological thermometers may be classed chiefly into the following groups based on their preciseness:
1. The thermometers that record fairly accurately the specific temperature condition of formation of deposits.
2. The thermometers that provide an upper or a lower temperature, above or below which the deposits do not form
3. The thermometers that provide a range of temperature within which the deposits form; and
4. The thermometers that serve as rough indications of temperatures of formation of mineral deposits.
The presence of two or more of less precise geological thermometers in a deposit narrows the range of temperature of formation for the deposits
How can minerals deposits be formed; GEOLOGICAL PROCESSES; Ore Fluids; Ore Forming Processes; Concentrating Processes; Magmatic mineral deposits; Residual mineral deposits ; Placer deposits; Sedimentary mineral deposits; Metamorhogenic mineral deposits; Hydrothermal mineral deposits ; Magmatic Deposits
Cumulate deposits: fractional crystallization processes can concentrate metals (Cr, Fe, PGE, Pt, Ni, Ti, Diamond ))
Pegmatites : late staged crystallization forms pegmatites and many residual elements are concentrated (Li, Ce, Be, Sn, U, Rare Earths (REE), Feldspar, Mica, Gems).
magmatic deposits; Mode of Formation of Magmatic Ores Deposits; Mode of Formation of Orthomagmatic Ores ; Fractional Crystallization (or Crystal fractionation ); Magmatic (or Liquid ) Immiscibility; Simple crystallization without concentration (Dissemination); Segregation of early formed crystals; (Layer Types); Injection of material concentrated elsewhere by differentiation Residual liquid segregation; Residual liquid injection; Immiscible liquid segregation; Immiscible-liquid-injection; Early magmatic deposit; Late magmatic deposit; Types of Magmatic Ore Deposits:Chromite; Fe-Ti (± V) oxides; Ni – Cu – Fe (± Pt) sulfides; Platinum Group Elements (PGEs); REE, and Zr in Carbonatites; Diamond in kimberlites.
Slides related to wall rock alteration.In these slides it is described that how host rock behave when it comes in contact with the hydro thermal fluid coming from deep Earth (Mantle) and their results.
THE PRESENCE AND VARIETY OF A PARTICULAR PLANTS
SPECIES IN THE AREA OF MINERALISATION HAVE BEEN RECOGNISED AS A GUIDE TO LOCATING ORE, METHOD,UNIVERSAL INDICATORS , UNIVERSAL INDICATOR ,LOCAL INDICATOR
Metallogenic Epoch and Province
Metallogenetic Epochs
Metallogenetic epochs, as defined above, are specific periods characterised by formation of large number of mineral deposits. It does not mean that all the mineral deposits formed during a definite metallogenetic epochs. In India the chief metallogenetic epochs were:
1. Precambrian
2. Late Palaeozoic
3. Late Mesozoic to Early Tertiary
A presentation on Hydrothermal wall rock alteration with case studies on geophysical applications.
References : https://drive.google.com/drive/folders/16VSZMPMASMNVB47JdBUa_7udBk1qvK2U?usp=sharing
SUPERGENE ENRICHMENT; Definition; Zones; Morphology of Zoning; Oxidized zone ; Supergene zone ; Gossans and Cappings; Chemical Changes Involved; Electrowinning; Formation of Copper Oxides
Sulfide mineralization are the main resource for exploiting Pb, Zn, and Cu metals in Egypt.
Sulfide mineralization is represented by four sulfide types of the different setting, lithology and ages, namely:
i) Lead-Zinc sulphide Deposits
ii) Cu-NiCo sulphide Deposits
This type of mineralization is well represented in Abu Swayel in South Eastern Desert. The ore is closely related to mafic-ultramafic and gabbro of ophiolitic rocks.
iii) Cu-Ni sulphide deposits
This type of mineralization occurs in layered mafic-ultramafic intrusions like gabbro rocks at Akarm and El Geneina .
iv) Stratiform Massive Sulphide (Zn-Cu-Pb) Deposits
This type of mineralization is represented by a group of small lenses associated with talc deposits in South Eastern Desert at: Um Samuki, Helgit, Maakal, Atshan, Darhib, Abu Gurdi, and Egat.
In this presentation we discuss cobalt crusts, its classification, Occurrence and Distribution, Formation, Texture, Mineralogy, Scope for future mining and exploration.
Slides related to wall rock alteration.In these slides it is described that how host rock behave when it comes in contact with the hydro thermal fluid coming from deep Earth (Mantle) and their results.
THE PRESENCE AND VARIETY OF A PARTICULAR PLANTS
SPECIES IN THE AREA OF MINERALISATION HAVE BEEN RECOGNISED AS A GUIDE TO LOCATING ORE, METHOD,UNIVERSAL INDICATORS , UNIVERSAL INDICATOR ,LOCAL INDICATOR
Metallogenic Epoch and Province
Metallogenetic Epochs
Metallogenetic epochs, as defined above, are specific periods characterised by formation of large number of mineral deposits. It does not mean that all the mineral deposits formed during a definite metallogenetic epochs. In India the chief metallogenetic epochs were:
1. Precambrian
2. Late Palaeozoic
3. Late Mesozoic to Early Tertiary
A presentation on Hydrothermal wall rock alteration with case studies on geophysical applications.
References : https://drive.google.com/drive/folders/16VSZMPMASMNVB47JdBUa_7udBk1qvK2U?usp=sharing
SUPERGENE ENRICHMENT; Definition; Zones; Morphology of Zoning; Oxidized zone ; Supergene zone ; Gossans and Cappings; Chemical Changes Involved; Electrowinning; Formation of Copper Oxides
Sulfide mineralization are the main resource for exploiting Pb, Zn, and Cu metals in Egypt.
Sulfide mineralization is represented by four sulfide types of the different setting, lithology and ages, namely:
i) Lead-Zinc sulphide Deposits
ii) Cu-NiCo sulphide Deposits
This type of mineralization is well represented in Abu Swayel in South Eastern Desert. The ore is closely related to mafic-ultramafic and gabbro of ophiolitic rocks.
iii) Cu-Ni sulphide deposits
This type of mineralization occurs in layered mafic-ultramafic intrusions like gabbro rocks at Akarm and El Geneina .
iv) Stratiform Massive Sulphide (Zn-Cu-Pb) Deposits
This type of mineralization is represented by a group of small lenses associated with talc deposits in South Eastern Desert at: Um Samuki, Helgit, Maakal, Atshan, Darhib, Abu Gurdi, and Egat.
In this presentation we discuss cobalt crusts, its classification, Occurrence and Distribution, Formation, Texture, Mineralogy, Scope for future mining and exploration.
MANGANESE ORE DEPOSITS, Sedimentary Manganese Deposits, Types of Sedimentary Manganese, Classification, Manganese Nodules, EGYPTIAN MANGANESE ORE DEPOSITS , IRON ORE DEPOSITS, Cycle of Iron , Ironstone (Sedimentary iron) Ore Deposits, Bog Iron Ore Deposits, Principal iron-bearing minerals, Geochemical stability of iron-rich minerals, World Resources Iron Deposit, EGYPTIAN IRON ORE DEPOSITS, Iron ore deposit of sedimentary nature, Sinai: Gabal Halal iron ore deposit, Aswan iron Ore Deposits, Bahariya iron Ore Deposits
[American mineralogist] a terrestrial magmatic hibonite grossite-vanadium ass...James AH Campbell
[American mineralogist] a terrestrial magmatic hibonite grossite-vanadium assemblage desilication and extreme reduction in a volcanic plumbing system mount carmel israel
A terrestrial magmatic hibonite grossite-vanadium assemblage desilication an...James AH Campbell
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Evidence of Clay Mineralization on Tropical Sediments from Afikpo Graben, SE ...Premier Publishers
Sedimentation in the Afikpo graben (SE Nigeria) thus commenced with the Campano-Maastrichtian marine and paralic shales of the Enugu and Nkporo Formations, overlain by the Mamu Formation. The fluviodeltaic and subtidal sandstones of the Ajali Formation lie on the Mamu Formation. The overlying deltaic Nsukka and marine shales of the Imo and Ameke Formations were deposited during the Paleocene. These two formations (Mamu and Nsukka) consist of a cyclic succession of coals, carbonaceous shales, silty shales and siltstones interpreted as deltaic deposits. The primary minerals are Feldspar, Quartz, Pyroxenes, Haematite. The secondary minerals are further classified into two major groups of 1:1 clay minerals and 2:1 clay minerals. The 1:1 clay minerals are kaolinite and halloysite, while the examples of 2:1 mineral are montmorillonite, vermiculite and illite. Clay fractions of shale samples obtained from the Cretaceous Mamu and Nsukka Formations in the Afikpo graben, South eastern Nigeria through the process of sedimentation technique were air – dried and analyzed using the empyrean diffractometer manufactured by Panalytical to determine the presence of clay mineralization in the area. The result shows that the bulk mineral composition of the shales comprises of quartz, clay minerals, carbonates and iron rich minerals, while the dominant clay mineral is kaolinite (70 – 80%) with minor amounts of illite (4 – 7 %) and smectite (10 – 20) as typical composition of tropical sediment.
IRON ORE DEPOSITS IN EGYPT ; EGYPTIAN IRON ORE DEPOSITS; Iron ore deposit of sedimentary nature; Sinai: Gabal Halal iron ore deposit; Western Desert:; Aswan iron Ore Deposits; Bahariya iron Ore Deposits; The Banded Iron ore deposits (BIFs), Geologic Setting BIFs, General Characteristics of the Egyptian Banded Iron Ores; Are the Egyptian Banded Iron Ores Unique?; Genesis of Egyptian Banded Iron Formation
Pyrolusite of Umm Bogma, South Sinai, EgyptMostafa Masoud
Presentation on Pyrolusite of Umm Bogma
Reference
Khalifa, I. H., & Seif, R. A. (2014). Geochemistry of manganese-iron ores at Um Bogma area, west central Sinai, Egypt. International Journal of Advanced Scientific and Technical Research, 6, 258-283.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
How to Split Bills in the Odoo 17 POS ModuleCeline George
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It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
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Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
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1. Fe-Deposits
Supervision by: Dr. Ahmed M. ZayedSupervision by: Dr. Ahmed M. Zayed
Edited by : Mostafa Abdel Azim MasoudEdited by : Mostafa Abdel Azim Masoud
Beni-Suef University- EgyptBeni-Suef University- Egypt
4. They are deposits of Precambrian age characterized by
being thin to medium bedded interlaminations of iron
oxide, iron carbonate, or iron silicate materials (layer
rich in iron ≥15% Fe ) with chert, quartz, carbonate, or
jasper (layer poor in iron).
Due to the extreme age of these formations, almost all
BIF have undergone some faulting, fracturing, folding,
compaction, veining, intrusions and metamorphism.
Although all BIF formations are probably
metamorphosed to some degree, but their general
character is still sedimentary.
N.B. BIFs are known as “taconite” in North America.
Definition:
7. Oxide facies: Magnetite and hematite (taconite(.
Silicate facies: Cummingtonite, grunerite, greenalite, minnesotaite,
stilpnomelane, Fe chlorites, and Fe amphiboles.
Carbonate facies: Ankerite and siderite.
Sulphide facies: pyrite.
The classic facies zonation
from shallow to deeper
water deposition is:
oxide to carbonate to
sulphide.
8. Classification of BIFs according to
geologic setting:
Three main types of banded iron formations are recorded allover
the world :
9. Algoma type (Archean age; 3500-3000 Ga)
→Formed by turbidity currents near island
arc trenches and typically sub marine
volcanogenic origin,
Island arc depositional environment.
The iron bands alternate with
metavolcanics and poyroclastics.
Lake- superior type (Early Proterozoic age; 2500-2000 Ga)
→ Shelf sediments precipitated in stable shelf or marginal basin (foreland or back-arc
basins), continental margin depositional environment.
The iron band alternate with metasediments.
Rapitan type ( 1000-500 Ga )
→Non volcanic type which formed in non volcanic rift zone at continental margin
10. Origin:
Sedimentary origin:
1.BIF has been considered to be ferruginous sedimentary rock, which resulted from
the weathering, transportation, and precipitation of iron derived from landmasses
by erosion, with rhythmic deposition of iron as oxides, hydroxides, and hydrous
oxide-silicate minerals in the sedimentary systems.
2.Iron formations were deposited as end members, or final products, of carbonate
sedimentary cycles.
3.Depositions of iron formations resulted after buildup of iron concentration in the
sea, depending on pH and Eh conditions, the gradual buildup of oxygen and the
depletion of CO2 in the atmosphere lead to the precipitation of iron in seawater as
magnetite, hematite, and siderite.
4.Iron formation resulted from the upwelling of cold, deep seawater onto a warm
continental shelf.
The cold water would be saturated in CO3, Ca2+ , and Fe2+.
Fe2+ would precipitate as ferric oxides, hydroxides, or silicates with increased
temperature, oxidation, and CO2 loss. The same waters would supersaturated in
amorphous silica and would precipitate chert.
11. Volcanic origin:
1.Silica and iron associated with volcanism were poured out on the sea floor from
springs of magmatic origin.
2.Iron formation beds were originally deposited as more thickly bedded fine-grained
ferruginous tuffs and other iron-rich sediments that were diagenetically oxidized and
silicified under the influence of solutions that were partly volcanic in origin.
12. The banded iron layers were formed in sea water as the result of
oxygen released by photosynthetic cyanobacteria (blue green algae),
combining with dissolved iron in Earth's oceans to form insoluble iron
oxides, which precipitated out, forming a thin layer on the substrate,
which may have been anoxic mud (forming shale and chert).
Biogenic origin:
13. Occurrences in Egypt:
The Egyptian Precambrian
iron formations (BIF) and
the host metavolvanics or
metasediments constitute
widespread and easily
recognizable sequences at
134 localities distributed in
the Central Eastern Desert
(CED) between latitudes 25˚
12` and 26˚ 31`N.
Among them : ( Umm Nar,
G.El Hadid, Umm Khamis El
Zarga, W.Kareem, and W.
Dabbab ).
14. Two main genetic models have been postulated for the Precambrian Egyptian BIFs
including the Umm Nar occurrence:
1.A purely sedimentary origin during the accumulation of the Precambrian geosynclinal
sediments,
2.A volcanogenic origin related to submarine magmatism and hydrothermal activity of
pan African island arc assemblages.
Observations:
The original sediments of the BIF host rocks were most probably sandy and calcareous
shales or mudstones, sandstones, and limestones which are now metamorphosed under
greenschist and low amphibolite facies conditions.
Evidence of sedimentary origin of these
metamorphic facies:
1.The geochemical characters of these rocks.
2.The bedded nature of these rocks and their
characteristic mm to cm rhythmic intercalations.
3.The absence of relics of igneous textures or
exsolution pattern.
The lithofacies association of the metasediments
and BIF and their syn-sedimentary structures
(rhythmic bedding and laminations, cross
lamination and flaser structure) suggest deposition
in shelf environment.
15. (B) according to the present conclusions, the Egyptian
Precambrian BIFs can be preliminary reclassified into
two main genetic types of different ages:
1. Early Proterozoic BIF of pre pan-African shelf
environment, represented by the studied Umm Nar
occurrence, and
2. Late Proterozioc BIF of Pan-African island arc
environment, represented by some other occurrences.
e.g. G. El Hadid, W. Karim and El Dabah
16. Two main genetic models have been postulated for the
Precambrian Egyptian BIFs including the Umm Nar
occurrence:
(1)A purely sedimentary origin during the accumulation of
the Precambrian geosynclinal sediments, and
(2)A volcanogenic origin related to submarine magmatism
and hydrothermal activity of pan African island arc
assemblages.
→ A detailed geologic, structural, and petrographic studies
of Umm Nar BIFs are included in the publication of El Aref,
Abdel Wahed, El Duogdoug and El Manawi (1993).and
they concluded the followings:
(a) The original sediments of the BIF host rocks were most
probably sandy and calc. shales or mudstones, sandstones,
and limestones now metamorphosed under greenschist and
low amphibolite conditions.
19. Ironstone is a fine-grained, heavy and compact
sedimentary rock.
Its main components are the carbonate or oxide of
iron, clay and/or sand. It can be thought of as a
concretionary form of siderite.
Ironstone also contains clay, and sometimes calcite
and quartz.
Definition:
21. Bog iron ores:
Formed in peat bogs, marshes, swamps and lakes in regions of
Pleistocene glaciations and in volcanic lakes.
1.Lake ores are formed as oolitic goethite in agitated waters along lake
margins.
2.Volcanic lake ores are made up of purely limonitic material with up to
50% Fe and owe their origin to iron bearing thermal springs.
Clinton type iron ore:
is characterized by :
1.The absence of chert.
2.Presence of hematite and chamosite oolites.
3. Herring bone cross statifications implying intertidal deposition.
Black band & sideritic iron ores:
These are fresh water deposits as thin beds, discontinuous lenses or
nodules associated with coal.
23. Origin:
Source of Iron:
1.From weathering processes upon land, especially in the tropical climate and the subsequent
introduction of iron by rivers into seas and oceans, mostly in the adsorbed form or as colloidal
suspensions. (sedimentary origin)
2.Iron formations are attributable to submarine exhalations of fluids and the ooidal ironstones
especially attributed to hypersaline fluids which have risen to marine bottom along deep faults
(Kimberly, 1989). (volcanic origin)
3.The microbial and the other digenetic processes affecting the clayey sediments, rich in organic
matter and deposited in deltas, lagoons, and stagnant anoxic basins, lead to mobilization of iron
(fe3+→fe2+). According to this hypothesis, the anoxic sediments could have acted as very
important source and temporary storage of huge quantities of iron. (biogenic origin)
Origin of Ooids:
1.By metasomatic ferruginization of ooidal limestones.
2.Ooides growing in the state of suspension, in an agitated, high energy aqueous environment.
24. SUGGESTED ENVIRONMENTAL SETTINGS
OF THE OOLITIC IRONSTONES
Continental Environments Marine Environments
Low Energy Env. High Energy Env.
Lagoon
Lacustrine
Shallow / Deep Shelf
Tidal Bars
Deltaic Bars
Upon
Submarine
Swells
Lateritic Soil
/Hydromorphic Env.
Fluvial Env.
26. 2 5
2 5 3 0
3 5
M ED ITER R A N EA N SEA
RED
SEA
K H A R G A
O A S I S
D A K H L A
O A S I S
FA R A F R A
O A S I S
E L B A H A R I Y A
O A S I S
S IW A
O A S I S
FA IY U M
O A S IS
C A I R O
S a lu m
A l ex a n d r ia
3 0
1
2
3
4
5
6
7
8
A S W A N
1 0
S I N A I
1= Jurrasic ooltic ironstone, G abal E l M aghara
2= Low er C retaceous oolitic ironstone, G abal E l H alal
3-7= U pper C retaceous oolitic ironstones, w estC entral Sinai (3), north Wadi Q ena (4),
A sw an region (5,6,7)
8-10= M iddle E ocene oolitic ironstones (E l B ahariya region
O C C U R R E N C E S O F T H E E G Y PT IA N P H A N E R O Z O IC
O O L IT IC IR O N ST O N E S
9
27. Case Study:
El Baharyia Ironstones
Geological map of El
Bahariya Depression
(El Aref et al., 2006)
29. Types of iron deposits and genesis:
According to El Sharkawi et al., (1987), the Bahariya iron ore can be classified into threeAccording to El Sharkawi et al., (1987), the Bahariya iron ore can be classified into three
types:types:
Genetic type (I):Genetic type (I):
OOolitic-pisolitic iron ore of limonitic composition.
The host rock is limestone of the Naqb Fm.
Mainly shoal and lagoonal depositional environment.
Genetic type (II): (Karst ore)Genetic type (II): (Karst ore)
Stratabound supergene ore formed due karstification of Qazzun Fm. (Nummulitic
limestone).
It is barite-bearing, hematite, goethite iron ore (Karst ore).
Karst textures are dominant.
Genetic type (III):Genetic type (III):
Statabound supergene ore formed of green sand followed by lateritic weathering of
glauconite in the Upper Eocene HamraFm.
The ore is mainly composed of glauconite and hematite.
Editor's Notes
#Differences between BIFs and Ironstones:
Age: BIFs are Precambrian and ironstones are Phanerozoic
N.B. Phanerozoic BIFs are recorded, but Phanerozoic is not the age of their formation, it is the age of the tectonic events that led to their exposure like the Alpine, Caledonian orogenies.
2. Textures: BIFs (banding), Ironstones (ooids, peloids, onchoids, etc..)
3. BIFs are affected more by tectonism and metamorphism
#Banded: because BIF is banded and takes all the scales of banding (thick banding-thin banding-laminae-varves).
#Formation: not the stratigraphic term, but the same as its English meaning.
#BIFs are affected by different sedimentary structures:
Primary or synsedimentary deformational textures: BIFs are affected by syndeformational tectonism (like slumping, cross-lamination and folding (as it appears here in the photo))
The folding in this photo is restricted to a definite zone and is not found above or below it, that’s why we say that it is synsedimentary.
2. Secondary or postsedimentary structures (like folding and faulting and veining)
#The dark band is Jasper, and the light band is the Fe-rich band
The black to gray to silver colored iron oxide layers contrast with the iron rich chert, jasper and shales which are generally red in color.
#Jasper: a form of chalcedony (cryptocrystalline Qz), it is opaque impure variety of silica, Jasper is basically chert which owes its red color to iron III inclusions
#Jaspilite is a BIF rock that often has distinctive bands of jasper.
≥15% Fe in the Iron-rich layer only not in the bulk BIF sample with its different bands, where when we make chemical analysis for BIFs, we analyze each band alone.
Rolling over the sustrate at the interface between seawater and the deposited sediments on a core