Jurassic - Saudi Arabia

1. GEOL 501 - Geology of the Middle East
Instructor: Dr. Khalid Al-Ramadan
Assignment 4
Jurassic System
Shaqra Group
Omar Atef Radwan
g201306050
ESD

2. OUTLINE
• Jurassic system around the world
– Paleogeography
– Fauna & Flora
• Jurassic System in Saudi Arabia
– Stratigraphic units
– Paleoenvironments
– Sequence stratigraphy
– Petroleum potentiality
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3. Introduction
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http://www.stratigraphy.org/

4. Paleogeography
Early Jurassic: Rifting of India from
Africa/Arabia begins.
India separates from Gondwana by
Late Jurassic.
4
Simmons et al., 2007

5. Fauna & Flora
• Many of today’s common creatures
evolved during the Jurassic:
lobsters, sharks, and major families
of insects (flies, bees, ants,
butterflies, and moths).
• The dinosaurs were highly
diversified during the Jurassic and
reached their maximum size,
becoming the largest terrestrial
animals ever to live.
• Widespread plant growth and coal
formation suggest a warm, moist
climate.
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6. 6Rausch et al., 2014
Jurassic System in Saudi Arabia

7. Stratigraphic units
• Shaqra Group ranks as the most economically significant
lithostratigraphic unit of Saudi Arabia
– Hosts twelve hydrocarbon reservoirs, including the Arab-D Reservoir within
the world’s largest oil field at Ghawar
• The Shaqra Group lies unconformably upon the Minjur Formation, of
Late Triassic age, and is overlain by the Sulaiy Formation, of Berriasian
age.
• Consists of seven formations of which most are carbonate and some
are partly evaporitic. Siliciclastics are uncommon.
• Comprised of, in ascending stratigraphic order:
– Marrat
– Dhruma
– Tuwaiq Mountain
– Hanifa
– Jubaila
– Arab
– Hith
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8. Stratigraphic units
The Lower Jurassic succession
• includes the Marrat Formation,
102.5 m thick, that lies
unconformably on the Triassic
Minjur Formation
• Consists of interbedded marine
sandstone, carbonate and
claystone deposits that are
Toarcian or older in age
8Hughes, 2008

9. Stratigraphic units
The Middle Jurassic succession
• represented by the Dhruma and
Tuwaiq Mountain formations.
Dhruma Formation
• 336 m thick and lies
unconformably on the Marrat
Formation.
• mainly composed of carbonate in
the subsurface, Carbonate and
claystone in the central part of the
outcrop area, and siliciclastics in
outcrops to the north and south.
• defined with seven informal units
D1 to D7
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Hughes, 2004

10. Stratigraphic units
The Middle Jurassic succession
• represented by the Dhruma and
Tuwaiq Mountain formations.
Tuwaiq Mountain Formation
• lies unconformably on The Dhruma
Formation
• consists mostly of shallow-marine
lagoon and stromatoporoid
carbonates of Middle to Late
Callovian age with a combined
thickness of 295 m.
• Members:
– Unit T1 or Baladiyah,
– Unit T2 Or Maysiyah
– Unit T3 or Daddiyah.
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Hughes, 2004

11. Tuwaiq Escarpment
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12. 12
Grainger, 2007
Tuwaiq Escarpment

13. Stratigraphic units
The Upper Jurassic succession
• consists of the Hanifa, Jubaila, Arab
and Hith formations.
Hanifa Formation
• lies disconformably upon the
Tuwaiq Mountain Formation
• 126 m thick and consists of a lower
muddy carbonate unit and an
upper stromatoporoid and
lagoonal carbonate lithofacies.
• Subdivided into:
– Lower Hawtah Member (H1)
– Upper Ulayyah Member (H2)
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Hughes, 2004

14. Stratigraphic units
The Upper Jurassic succession
• consists of the Hanifa, Jubaila, Arab
and Hith formations.
Jubaila Limestone Formation
• lies disconformably upon the
Hanifa Formation
• Consists of moderately deep
marine carbonates in the lower
part that is overlain by a shallow
marine stromatoporoid-associated
assemblage.
14
Hughes, 2004

15. Stratigraphic units
The Upper Jurassic succession
• consists of the Hanifa, Jubaila, Arab
and Hith formations.
Arab Formation
• approximately 54 m thick in
outcrop
• consists of four stacked carbonate-
evaporite cycles, named Arab-D to
Arab-A in ascending order.
Hith Formation
• Consists mostly of anhydrite but
has an upper carbonate unit
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Hughes, 2004

16. Paleoenvironments
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Al-Husseini, 1997
• During the Jurassic, the
Arabian Peninsula was located
on the southern margin of the
Tethys Ocean, and was the site
of an extensive shallow
marine platform.
• Scattered across the plat
form were localised deeper
areas considered to be intra-
shelf basins flanked by basin
margins colonised
predominantly by
stromatoporoid banks with
subsidiary corals

17. • (TMS) Tectonostratigraphic
megasequence AP7 lasted
some 33 my and was
dominated by Jurassic
carbonate platform, ramp
and intra-shelf basin
sediments
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• The base of the TMS is marked by the late Toarcian unconformity near the top of the Mus and
Marrat formations resulting from major rifting at the northern end of the plate, which generated
large volumes of new accommodation space.
• The top of this TMS is marked by the widespread early Tithonian unconformity hiatus surface,
which overlies the Late Jurassic evaporite deposits of the Gotnia and Hith formations. This surface
results from a combination of gentle structuring associated with inversion (in the north), the
successful spreading of India from Oman
Sequence Stratigraphy
Sharland, 2001

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Petroleum potentiality
• Source rock: Tuwaiq Mountain and Hanifa
formations developed within the intra-
shelf basins during the Callovian and
Oxfordian
• Reservoirs: developed in grainstone facies
associated with the late high stand
systems tracts of each formation
• Seals: developed and formed by
transgressive mudstones that characterize
the basal parts of each formation
Hughes, 2008

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20. References
• Al-Husseini, M. I. (1997). Jurassic sequence stratigraphy of the western and southern
Arabian Gulf. GeoArabia, 2(4), 361-382.
• Cohen, K.M., Finney, S.C., Gibbard, P.L. & Fan, J.-X. (2013; updated) The ICS
International Chronostratigraphic Chart. Episodes 36: 199-204. URL:
http://www.stratigraphy.org
• Grainger D (2007) The geologic evolution of Saudi Arabia—geonotes 1–16 and
geologic excursion 1–6. Saudi Geological Survey, Jeddah, p 264
• Haq, B. U., & Al-Qahtani, A. M. (2005). Phanerozoic cycles of sea-level change on the
Arabian Platform. GeoArabia, 10(2), 127-160.
• Hughes, G. W. (2008). Biofacies and palaeoenvironments of the Jurassic Shaqra
group of Saudi Arabia. Volumina Jurassica, 6(6), 33-45.
• Hughes, G.W. (2004). Middle to Upper Jurassic Saudi Arabian carbonate petroleum
reservoirs: biostratigraphy, micropalaeontology and palaeoenvironments.
GeoArabia, v. 9, no. 3, p. 79-114.
• Sharland, P. R. (2001). Arabian Plate Sequence Stratigraphy. Gulf PetroLink.
• Simmons, M. D., Sharland, P. R., Casey, D. M., Davies, R. B., & Sutcliffe, O. E. (2007).
Arabian Plate sequence stratigraphy: Potential implications for global
chronostratigraphy. GEOARABIA-MANAMA-, 12(4), 101.
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