Asmari Formation

Last updated

The Asmari Formation is a geological formation in western Iran. Located in the western Zagros Mountains, it is a carbonate formation that largely consists of limestone, dolomitic limestone, dolomite, and marly limestone. [1] There are also smaller amounts of anhydrite, lithic sandstone, and limey sandstone. [1] The formation dates to the Oligocene and Miocene periods and is a major hydrocarbon reserve. [2] [3] It has been producing oil since the 1930s. [4] It also forms a major aquifer, which discharges at various springs in the Zagros region. [5]

The Asmari Formation's basic biostratigraphy was established in the 1950s and it was formally described in 1965. [4] It consists of carbonate platforms that were formed in 6 distinct stages. [3] The formation is named after the Asmari Mountains southeast of Masjed Soleyman, and its type sample was taken from the Tang-e Gel Torsh in these mountains. [6]

The Asmari Formation was deposited at a time when the Tethys Ocean was finally closing and the Zagros Mountains were first rising. [6] During this period, the region was a shallow ocean gradually getting less deep. [6] By the time of the succeeding Gachsaran Formation, this process had culminated in the sea shrinking to lagoons. [6]

In the southwestern Zagros, the Asmari Formation sits on top of the Pabdeh Formation. [1] In the Fars and Luristan regions, the Asmari Formation sits on top of the Jahrum and Shahbazan Formations. [1] The Asmari Formation is thickest in the northeastern part of the Dezful Embayment. [1]

The formation has various microfossils including planktonic foraminifera, echinoids, red algae, ostracoda, and oncoids. [3] Individual species include Globigerina , Turborotalia cerroazulensis, Hantkenina , Nummulites , Lepidocyclina , Miogypsina , Elphidium , Peneroplis farsenensis, and Borelis melo curdica and Borelis melo melo. [4]

See also

Related Research Articles


The Thrace Basin is the largest and thickest Cenozoic sedimentary basin in Turkey. Most of the basin lies in the European side of the country, northwest of Istanbul, with portions extending into Greece and Bulgaria. It is triangular shaped, trends WNW-ESE and was formed in late Middle Eocene to latest Oligocene times. The basin is the location of gas and oil wells.

<span class="mw-page-title-main">Alwand River</span>

The Alwand or Halwan is a river in eastern Iraq and western Iran. It rises in the Zagros Mountains in Iran.

<span class="mw-page-title-main">Gulf of Suez Rift</span> Continental rift zone that was active between the Late Oligocene and the end of the Miocene

The Gulf of Suez Rift is a continental rift zone that was active between the Late Oligocene and the end of the Miocene. It represented a continuation of the Red Sea Rift until break-up occurred in the middle Miocene, with most of the displacement on the newly developed Red Sea spreading centre being accommodated by the Dead Sea Transform. During its brief post-rift history, the deepest part of the remnant rift topography has been filled by the sea, creating the Gulf of Suez.

<span class="mw-page-title-main">Orange Island (Florida)</span>

Orange Island is the earliest emergent landmass of Florida dating from the middle Rupelian ~33.9—28.4 Ma. geologic stage of the Early Oligocene epoch and named for Orange County, Florida, United States of America.

<span class="mw-page-title-main">Zagros fold and thrust belt</span> Geologic zone

The Zagros fold and thrust belt is an approximately 1,800-kilometre (1,100 mi) long zone of deformed crustal rocks, formed in the foreland of the collision between the Arabian plate and the Eurasian plate. It is host to one of the world's largest petroleum provinces, containing about 49% of the established hydrocarbon reserves in fold and thrust belts (FTBs) and about 7% of all reserves globally.

Ahvaz Field is a super-giant oil field located in Ahvaz, Khuzestan, Iran. It was discovered in 1953, developed by Anglo-Persian Oil Company and began production in 1954. Ahvaz field is one of the richest oil fields in the world with an estimated proven reserves around 65.5 billion barrels, and production is centered on 750,000 barrels per day (119,000 m3/d). The field is owned by National Iranian Oil Company (NIOC) and operated by National Iranian South Oil Company (NISOC).

<span class="mw-page-title-main">Geology of Iran</span>

The main points that are discussed in the geology of Iran include the study of the geological and structural units or zones; stratigraphy; magmatism and igneous rocks; ophiolite series and ultramafic rocks; and orogenic events in Iran.

<span class="mw-page-title-main">Geology of Ethiopia</span>

The geology of Ethiopia includes rocks of the Neoproterozoic East African Orogeny, Jurassic marine sediments and Quaternary rift-related volcanism. Events that greatly shaped Ethiopian geology is the assembly and break-up of Gondwana and the present-day rifting of Africa.

<span class="mw-page-title-main">Nam Con Son Basin</span>

The Nam Con Son Basin formed as a rift basin during the Oligocene period. This basin is the southernmost sedimentary basin offshore of Vietnam, located within coordinates of 6°6'-9°45'N and 106°0-109°30'E in the South China Sea. It is the largest oil and gas bearing basin in Vietnam and has a number of producing fields.

<span class="mw-page-title-main">Geology of Lebanon</span>

The geology of Lebanon remains poorly studied prior to the Jurassic. The country is heavily dominated by limestone, sandstone, other sedimentary rocks, and basalt, defined by its tectonic history. In Lebanon, 70% of exposed rocks are limestone karst.

<span class="mw-page-title-main">Geology of Somaliland</span>

The geology of Somaliland is very closely related to the geology of Somalia. Somaliland is a de facto independent country within the boundaries that the international community recognizes as Somalia. Because it encompasses the former territory of British Somaliland, the region is historically better researched than former Italian Somaliland. Somaliland is built on more than 700 million year old igneous and metamorphic crystalline basement rock.. These ancient units are covered in thick layers of sedimentary rock formed in the last 200 million years and influenced by the rifting apart of the Somali Plate and the Arabian Plate.

<span class="mw-page-title-main">Geology of Morocco</span>

The geology of Morocco formed beginning up to two billion years ago, in the Paleoproterozoic and potentially even earlier. It was affected by the Pan-African orogeny, although the later Hercynian orogeny produced fewer changes and left the Maseta Domain, a large area of remnant Paleozoic massifs. During the Paleozoic, extensive sedimentary deposits preserved marine fossils. Throughout the Mesozoic, the rifting apart of Pangaea to form the Atlantic Ocean created basins and fault blocks, which were blanketed in terrestrial and marine sediments—particularly as a major marine transgression flooded much of the region. In the Cenozoic, a microcontinent covered in sedimentary rocks from the Triassic and Cretaceous collided with northern Morocco, forming the Rif region. Morocco has extensive phosphate and salt reserves, as well as resources such as lead, zinc, copper and silver.

<span class="mw-page-title-main">Geology of South Dakota</span>

The geology of South Dakota began to form more than 2.5 billion years ago in the Archean eon of the Precambrian. Igneous crystalline basement rock continued to emplace through the Proterozoic, interspersed with sediments and volcanic materials. Large limestone and shale deposits formed during the Paleozoic, during prevalent shallow marine conditions, followed by red beds during terrestrial conditions in the Triassic. The Western Interior Seaway flooded the region, creating vast shale, chalk and coal beds in the Cretaceous as the Laramide orogeny began to form the Rocky Mountains. The Black Hills were uplifted in the early Cenozoic, followed by long-running periods of erosion, sediment deposition and volcanic ash fall, forming the Badlands and storing marine and mammal fossils. Much of the state's landscape was reworked during several phases of glaciation in the Pleistocene. South Dakota has extensive mineral resources in the Black Hills and some oil and gas extraction in the Williston Basin. The Homestake Mine, active until 2002, was a major gold mine that reached up to 8000 feet underground and is now used for dark matter and neutrino research.

<span class="mw-page-title-main">Geology of Bosnia and Herzegovina</span>

The geology of Bosnia & Herzegovina is the study of rocks, minerals, water, landforms and geologic history in the country. The oldest rocks exposed at or near the surface date to the Paleozoic and the Precambrian geologic history of the region remains poorly understood. Complex assemblages of flysch, ophiolite, mélange and igneous plutons together with thick sedimentary units are a defining characteristic of the Dinaric Alps, also known as the Dinaride Mountains, which dominate much of the country's landscape.

The geology of Mississippi includes some deep igneous and metamorphic crystalline basement rocks from the Precambrian known only from boreholes in the north, as well as sedimentary sequences from the Paleozoic. The region long experienced shallow marine conditions during the tectonic evolutions of the Mesozoic and Cenozoic, as coastal plain sediments accumulated up to 45,000 feet thick, including limestone, dolomite, marl, anhydrite and sandstone layers, with some oil and gas occurrences and the remnants of Cretaceous volcanic activity in some locations.

The geology of the United Arab Emirates includes very thick Paleozoic, Mesozoic and Cenozoic marine and continental sedimentary rocks overlying deeply buried Precambrian. The region has extensive oil and gas resources and was deformed during the last several million years by more distant tectonic events.

The geology of Iraq includes thick sequences of marine and continental sedimentary rocks over poorly understood basement rock, at the junction of the Arabian plate, the Anatolian plate, and the Iranian plate.

<span class="mw-page-title-main">Geology of Italy</span> Italy: Geology

The geology of Italy includes mountain ranges such as the Alps and the Apennines formed from the uplift of igneous and primarily marine sedimentary rocks all formed since the Paleozoic. Some active volcanoes are located in Insular Italy.

The geology of Yukon includes sections of ancient Precambrian Proterozoic rock from the western edge of the proto-North American continent Laurentia, with several different island arc terranes added through the Paleozoic, Mesozoic and Cenozoic, driving volcanism, pluton formation and sedimentation.

The Pabdeh Formation is a Late Eocene to Early Oligocene-aged geological formation in Iran. It outcrops along the Zagros Mountains. It was deposited in a deepwater environment in the upper bathyal zone of the Paratethys Sea, with these abyssal sediments being lifted high above sea level from the uplift of the Zagros fold and thrust belt as part of the Alpide orogeny.

References

  1. 1 2 3 4 5 Vaziri-Moghaddam, Hossein; Seyrafian, Ali; Taheri, Azizolah; Motiei, Homayoon (2009). "Oligocene–Miocene ramp system (Asmari Formation) in the NW of the Zagros basin, Iran: Microfacies, paleoenvironment and depositional sequence". Revista Mexicana de Ciencias Geológicas. 27 (1). Retrieved 26 October 2022.
  2. Abyat, Yasin; Abyat, Ahmad; Abyat, Abdolkhalegh (2019). "Microfacies and depositional environment of Asmari formation in the Zeloi oil field, Zagros basin, south-west Iran". Carbonates and Evaporatives. 34 (1583–93): 1583–1593. Bibcode:2019CarEv..34.1583A. doi:10.1007/s13146-019-00507-1. S2CID   155218201.
  3. 1 2 3 Khalili, Ardavan; Vaziri-Moghaddam, Hossein; Arian, Mehran; Seyrafian, Ali (2021). "Carbonate platform evolution of the Asmari Formation in the east of Dezful Embayment, Zagros Basin, SW Iran". Journal of African Earth Sciences. 181: 104229. Bibcode:2021JAfES.18104229K. doi:10.1016/j.jafrearsci.2021.104229.
  4. 1 2 3 Laursen, G.V.; Monibi, S.; Allan, T.L.; Pickard, N.A.H.; Hosseiney, A.; Vincent, B.; Hamon, Y.; van Buchem, F.S.P.; Moallemi, A.; Druillion, G. (2009). "The Asmari Formation Revisited: Changed Stratigraphic Allocation and New Biozonation". Shiraz. 1st International Petroleum Conference and Exhibition Shiraz 2009. 4. doi:10.3997/2214-4609.20145919. ISBN   978-90-73781-65-8 . Retrieved 26 October 2022.
  5. Karimi, Haji; Raeisi, Ezzat; Bakalowicz, Michel (2005). "Characterising the main karst aquifers of the Alvand basin, northwest of Zagros, Iran, by a hydrogeochemical approach". Hydrogeology Journal. 13 (5): 787–99. doi:10.1007/s10040-004-0350-4. S2CID   128560963 . Retrieved 20 October 2022.
  6. 1 2 3 4 Dehghanian, Mohammadsadegh (March 2021). "Bio-Sequence Stratigraphy of Asmari Formation in the Southeast of Norabad (Zagros Basin, SW Iran)" (Preprint). doi:10.21203/rs.3.rs-315337/v1. S2CID   233677820 . Retrieved 26 October 2022.{{cite journal}}: Cite journal requires |journal= (help)