GEOL 501 - Geology of the Middle East  Instructor: Dr. Khalid Al-Ramadan

Term Paper

 Evolution of Tethys Ocean

Omar Atef Radwang201306050

ESD

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• Introduction

• Paleogeography

• Paleotectonics 

• Paleoceanography

• Tethys Ocean and petroleum systems in the Middle

East

• References

OUTLINE

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INTRODUCTION

Erickson, 2002

• Eduard Suess in 1893• named after the ancient Greek

goddess of the sea

• an ancient ocean that existed from 250–50 Mya

• orientated east–west • separated the large continents of

Gondwana and Laurasia.

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• Proto-Tethys (Precambrian-Carboniferous)

• Paleo-Tethys (Ordovician-Jurassic)

• Neo-Tethys (Permian-Paleocene)

• Para-Tethys (Jurassic -Pliocene )

PALEOGEOGRAPHY

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PALEOGEOGRAPHY

Berra and Angiolini , 2014

Proto-Tethys • Ediacaran to the Carboniferous

(550–330 Ma)• formed when Pannotia was

broken up into four principal Paleozoic continents: Gondwana, Laurentia, Baltica, and Siberia

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PALEOGEOGRAPHY

Berra and Angiolini , 2014

• situated between the Siberia to and Gondwana

• Late Silurian: started to shrink • Late Devonian, the

microcontinent of Kazakhstania collided with Siberia, shrinking the ocean even more.

• Carboniferous: The ocean closed when the North China craton collided with Siberia-Kazakstania continent, while the Paleo-Tethys Ocean expanded.

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PALEOGEOGRAPHY

Muttoni et al., 2009

Paleo-Tethys • Ordovician-Jurassic• existed when Laurasia

and Gondwana-Land collided in the late Palaeozoic

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PALEOGEOGRAPHY

Muttoni et al., 2009

Paleo-Tethys• major dextral motion of

Laurasia relative to Gondwana

• transformation of Pangea from an Early Permian configuration of the B-type to a Late Permian configuration of the A-type

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PALEOGEOGRAPHY

Muttoni et al., 2009

• The Cimmerian Continent rifted off from the northern margin of Gondwana-Land mostly during the Permo-Triassic opening behind it the Neo-Tethys

• Palaeo-Tethys + the Cimmerian Continent + the Neo-Tethys + their continental margins = “Tethyan Realm”

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Neo-Tethys• Permian-Paleocene• Tethys Ocean continued to

expand westward, dividing Pangaea into the two large continents of Laurasia in the north and Gondwana in the south, creating an oceanic extension of the Tethys, which today forms the central Atlantic Ocean

Berra and Angiolini , 2014

PALEOGEOGRAPHY

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• After the early Cretaceous, the Neo-Tethys became the sole occupier of the Tethyan Realm

• Tethys ocean reaches its maximum extent.

Berra and Angiolini , 2014

PALEOGEOGRAPHY

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• In the Upper Cretaceous (84 Ma), the Indian plate began its very rapid northward drift at an average speed of 16 cm/year

• collision of the northwestern part of the Indian passive margin with Eurasia in the lower Eocene

• Indian continent continues its northwards ascent at a slower but still surprisingly fast rate of ~ 5 cm/year

Berra and Angiolini , 2014

PALEOGEOGRAPHY

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• The collision of the Arabian plate with Eurasia, the closure and the suturing of the Neotethyan Ocean, lasted between late Middle Miocene in the east and Late Pliocene-Quaternary in the west.

• The rate of motion of Arabia with respect to Eurasia has been fairly constant between 2 and 3 cm/yr since 56 Ma.

Berra and Angiolini , 2014

PALEOGEOGRAPHY

14Sharland, 2001 Frisch et al., 2010

PALEOGEOGRAPHY

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Para-Tethys• Remnants of the Tethys Ocean include the Mediterranean, Caspian, Aral,

and Black Seas (formerly an inland extension of Tethys known as the Paratethys).

Erickson, 2002

PALEOGEOGRAPHY

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PALEOTECTONICS

• Hercynian Orogeny

• Cimmerian Orogeny

• Alpine Orogeny

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PALEOTECTONICS

Dèzes, 1999

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• The Alpine-Himalayan chain includes (from west to east):Pyrenees, European Alps, Apennines, Dinarides, Carpathians, Anatolian Plateau, Caucasus, Alborz, Zagros, Kopeh Dagh, Makran, Hindu Kush, Karakorum, Tien Shan, Tibet, and the Himalayas stretches from Spain  to Indonesia is the result of a step wise closure Neo-Tethys sea way.

Frisch et al., 2010

PALEOTECTONICS

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PALEOTECTONICS

Frisch et al., 2010

• Zagros fold–thrust belt• Semail Nappe• Makran Trench

20Stow, 2010

PALEOCEANOGRAPHY 

Paleocurrent models for a general Pangea configuration is a westward-flowing equatorial surface current which, upon reaching the continental shelves of the western Tethys Seaway, deflected southeastward and northeastward; in the meanwhile, a deep water circulation brought cold waters from high latitudes to the equator. Ocean  upwellings  of  these  cold  and  nutrient-rich  bottom waters were created by monsoonal wind circulation along the Gondwanan margin

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PALEOBIOGEOGRAPHY

Stow, 2010

Paleoclimatology• Oxygen-isotope analyses of

marine limestones have shown that 125-85 Ma was a time of severe global warming due to a rapid increase in atmospheric carbon dioxide concentrations

Eustasy• This is consistent with

sequence stratigraphic evidence for sea-level maxima in mid-late Cretaceous times.

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PETROLEUM SYSTEMS IN THE MIDDLE EAST

• For petroleum to be successfully generated, migrated, accumulated, and preserved, all elements and processes of the petroleum system should be present, including:– organically rich and thermally matured source rocks– porous-permeable reservoir rocks – effective extensive cap rocks– appropriate time relations between oil migration and trap formation

Obviously, the Middle East qualifies all these conditions to a high degree and quality.

• The paleogeographic and tectonic evolution of the southern Tethys area during the Phanerozoic plays an important role in determining the distribution of the source rocks and reservoirs as well as the origin of stratigraphic and tectonic traps

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TETHYS OCEAN – OIL GENERATION

Sorkhabi, 2010

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• most of the giant oil and gas fields known until 2000 are related to:– continental passive margins facing the major ocean basins (34.66%)– continental rifts and overlying sag basins (especially failed rifts at the edges or

interiors of continents; 30.90%)– collisional margins produced by terminal collision between two continents

(19.73%).

• Due to the geodynamic evolution of this area, rift basins (mainly formed due to the opening of the Tethys oceans and to the extensional events affecting North Africa) rapidly evolved  to passive margins  (e.g., evolution of the peri-Gondwanan blocks) and then to active margins, with the development of collision-related  basins  (e.g., foredeep related to the accretion of the peri-Gondwanan blocks to the southern margin of Eurasia).

TETHYS OCEAN – OIL ACCUMULATION

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TETHYS OCEAN – OIL ACCUMULATION

Berra and Angiolini , 2014

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TETHYS OCEAN – SEALS

• Apart from marine shale and marl cap rocks, many Middle East basins also contain evaporite beds, which are efficient seals because of their ductility. The main evaporate horizons include;– Triassic interbedded evaporates – Late Jurassic Gotnia-Hith Formation – Miocene Gachsaran Formation.

Sorkhabi, 2010

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TETHYS OCEAN – OIL TRAPING

• Oil fields, located in the strongly folded layers of the Zagros mountain chains, are elongate and parallel to the NW-SE trending folds. The petroleum was trapped during folding in the anticlines.

• On the Arabian Peninsula and in the western part of the Arabian Gulf, the oil fields trend N-S. Folds occur above similarly oriented horst structures which formed along normal faults in the Precambrian basement of the Arabian Shield.

• Circular oil fields in the eastern Arabian Gulf formed above salt diapirs that were formed by the rise of Early Paleozoic salt deposits.

Frisch et al., 2010

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CONCLUSIONS• The Tethys Ocean developed in at least three oceanic basins:

– Proto-Tethys (Precambrian-Carboniferous).– Paleo-Tethys (Ordovician-Jurassic).– Neo-Tethys (Permian-Paleocene).

• The Paleo-Tethys formed by gathering the continents around its frame forming the Pangaea as opposed to the Neo-Tethys that later formed by rifting.

• Palaeo-Tethys + the Cimmerian Continent + the Neo-Tethys and their continental margins = “Tethyan Realm”

• A double orogenic system resulted from the destruction of the Tethyan Realm: – the products of the closure of the Paleo-Tethys are the Cimmerides.– the products of the closure of major parts of the Neo-Tethys are called the Alpides.

• Remnants of the Tethys Ocean include the Mediterranean, Caspian, Aral, and Black Seas (Paratethys).

• The paleogeographic  and  tectonic evolution of the southern Tethys area during the Phanerozoic plays an important role in determining the distribution of the source rocks and reservoirs as well as the origin of stratigraphic and tectonic traps.

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• Dèzes, P., 1999. Tectonic and metamorphic evolution of the central Himalayan domain in southeast Zanskar (Kashmir, India) (Vol. 145). Institute of Geology and Paleontology, University of Lausanne.

• Muttoni, G., Gaetani, M., Kent, D.V., Sciunnach, D., Angiolini, L., Berra, F., Garzanti, E., Mattei, M., Zanchi, A., 2009. Opening of the Neo-Tethys Ocean and the Pangea B to Pangea A transformation during the Permian. GeoArabia 14, 17–48.

• Frisch, W., Meschede, M., Blakey, R.C., 2010. Plate Tectonics: Continental Drift and Mountain Building, 2011 edition. ed. Springer, Berlin; London.

• Berra, F. and L. Angiolini , 2014. The evolution of the Tethys region throughout the Phanerozoic: A brief tectonic reconstruction, inL. Marlow, C. Kendall and L. Yose, eds., Petroleum systems of the Tethyan region: AAPG Memoir 106, p. 1–27.

• Stow, D., 2010. Vanished Ocean: How Tethys Reshaped the World. Oxford University Press, Oxford.

• Erickson, J., 2002. Historical Geology: Understanding Our Planet’s Past, 2nd edition. ed. Facts on File, New York.

• Sorkhabi, Rasoul (2010) Why So Much Oil in the Middle East? GeoExpro, vol. 7, no. 1, pp. 20-26).

REFERENCES

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Frisch et al., 2010

35Stow, 2010

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