An example of mixed carbonate–pyroclastic sedimentation (Miocene, Central Basin, Iran)

Okhravi, Rasool; Amini, Abdolhossein

doi:10.1016/s0037-0738(98)00004-9

Cited by 24 publications

(19 citation statements)

References 13 publications

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“…Such an assemblage and the similarity with the standard microfacies types described by Wilson (1975) and Flügel (1982) indicate a shelf lagoon environment. A similar microfacies was reported from shelf lagoon environment of the Miocene, Central Basin, Iran (Okhravi and Amini 1998). 8.…”

Section: Environmental Interpretationsupporting

confidence: 84%

Depositional environment and sequence stratigraphy of the Oligo-Miocene Asmari Formation in SW Iran

Vaziri‐Moghaddam

Kimiagari

Taheri

2005

Facies

128

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The Asmari Formation, a thick carbonate succession of the Oligo-Miocene in Zagros Mountains (southwest Iran), has been studied to determine its microfacies, paleoenvironments and sedimentary sequences. Detailed petrographic analysis of the deposits led to the recognition of 10 microfacies types. In addition, five major depositional environments were identified in the Asmari Formation. These include tidal flat, shelf lagoon, shoal, slope and basin environmental settings and are interpreted as a carbonate platform developed in an open shelf situation but without effective barriers separating the platform from the open ocean. The Asmari carbonate succession consists of four, thick shallowing-upward sequences (third-order cycles). No major hiatuses were recognized between these cycles. Therefore, the contacts are interpreted as SB2 sequence boundary types. The Pabdeh Formation, the deeper marine facies equivalent of the Asmari Limestone is interpreted to be deposited in an outer slope-basin environment. The microfacies of the Pabdeh Formation shows similarities to the Asmari Formation.

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Section: Environmental Interpretationsupporting

confidence: 84%

Depositional environment and sequence stratigraphy of the Oligo-Miocene Asmari Formation in SW Iran

Vaziri‐Moghaddam

Kimiagari

Taheri

2005

Facies

128

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“…For the Esfahan-Sirjan and Qom basins, the gradual shifts from continental to offshore facies (and vice versa) indicate that sedimentation took place on extensive homoclinal ramps as already stated by Okhravi and Amini (1998) for the f-Member of the Qom Basin. The widespread occurrence of intertidal to shallow subtidal deposits and the absence of gravitative sediments (turbidites, slumps, etc.)…”

Section: Implications For the Paleogeographic And Paleobiogeographic supporting

confidence: 64%

“…Biostratigraphic studies on larger foraminifers were carried out by Rahaghi (1973Rahaghi ( , 1976Rahaghi ( , 1980, who assigned an Oligo-/Miocene age to the Qom Fm. More recently, a paleoenvironmental reconstruction based on microfacies analysis was attempted for the f-Member (Okhravi and Amini 1998). However, geological research of the Qom Fm.…”

Section: Introductionmentioning

confidence: 99%

The Oligo-/Miocene Qom Formation (Iran): evidence for an early Burdigalian restriction of the Tethyan Seaway and closure of its Iranian gateways

Reuter

Piller

Harzhauser

et al. 2007

Int J Earth Sci (Geol Rundsch)

211

168

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In the central Iranian Esfahan-Sirjan and Qom basins sedimentation of the Oligo-/Miocene Qom Formation took place on extensive mixed carbonate-siliciclastic ramps. During this time, both basins were positioned at the Eurasian margin of the Tethyan Seaway, which connected the western and eastern regions of the Tethys Ocean at least until the late Burdigalian. During the so-called Terminal Tethyan Event the Tethyan Seaway was then closed due to the collision of the African/Arabian and Iranian/Eurasian plates. Facies analysis of the sedimentary record of both basins indicates paleoenvironments ranging from terrestrial to open marine settings, including mangrove, restricted inner shelf lagoon, seagrass meadow, reefal, and deeper offshore environments. Recognition of eight depositional sequences and elaboration of an integrated biostratigraphic framework (calcareous nannoplankton, planktic and larger benthic foraminifers, gastropods, and pectinids) allow us to construct a basin-spanning stratigraphy. The assignment of the recognized sea-level lowstands to the Ru 3 to Bur 3 lowstands of the global sea-level curve enables a comparison with time-equivalent sections from the Zagros Basin, which was part of the African/Arabian Plate on the opposing southern margin of the Tethyan Seaway. The so calibrated sections display restrictions of the Tethyan Seaway and interruption of the south Iranian gateways between the Qom Basin and the Proto-Indopacific in relation to ongoing plate collision during the early Burdigalian.

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“…The spherical to slightly ellipsoidal alveolinids inhabit the unvegetated sediment surface, whereas the discoidal-shaped species (especially Peneroplis) are seagrass dwelling forms (Hottinger 1977;Eva 1980;Faber 1991). Okhravi and Amini (1998) recently introduced a depositional model for the "f member" of the Qom Formation. They studied three sections in the vicinity of Qom (all locations are very close to the section described herein) and reported a high percentage of in situ reef corals in the upper part of the limestone sequence.…”

Section: Porites-faviidae Assemblagementioning

confidence: 99%

“…The high diversity of Early Miocene coral faunas from southern Iran (McCall et al 1994) and Pakistan (Duncan 1880) can probably be attributed to a palaeogeographic position that was in an open marine connection with the Indopacific Ocean. Secondly, local factors, such as volcanic activity and related ash falls, recently described by Okhravi and Amini (1998) from the Early Miocene of the Qom basin, could have had an influence on the diversity of coral communities. Nevertheless, it has to be kept in mind that the coral fauna from the Qom back-arc basin was sampled at only two localities (Qom and Chalheghareh), whereas the faunas from Makran and the Aquitaine Basin are collections from many sections distributed over a large area.…”

Section: Comparison With Other Coral Faunas and Palaeobiogeographic Imentioning

confidence: 99%

Oligocene and Early Miocene coral faunas from Iran: palaeoecology and palaeobiogeography

Schuster¹,

Wielandt

1999

International Journal of Earth Sciences

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Oligocene and Early Miocene coral assemblages from three sections of central Iran are investigated with respect to their palaeoecological and palaeobiogeographic implications. These corals are compared with faunas from the Mediterranean Tethys and the Indopacific. Associated larger foraminifers are used for biostratigraphy and to support the palaeoecological interpretation. The studied sections are situated in the foreland basins of the Iranian Plate which is structured into a fore-arc and a back-arc basin separated by a volcanic arc. The coral assemblages from Abadeh indicate a shallowing-upward trend. Infrequently distributed solitary corals at the base of the section indicate a turbid environment. Above, a distinct horizon characterised by a Leptoseris-Stylophora assemblage associated with lepidocyclinids and planktonic foraminifers is interpreted as maximum flooding surface. Small patch reefs with a Porites-Faviidae assemblage are a common feature of Late Oligocene to Early Miocene coral occurrences and indicate water depths of less than 20 m. The diversity of the coral faunas shows marked differences. Oligocene corals from the Esfahan-Sirjan fore-arc basin comprise more than 45 species of 32 genera and occur in a wide range of environments. Early Miocene corals from the Qom back-arc basin are less frequent, show a lower diversity (13 genera with 15 species) and occur in single horizons or small patch reefs.

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An example of mixed carbonate–pyroclastic sedimentation (Miocene, Central Basin, Iran)

Cited by 24 publications

References 13 publications

Depositional environment and sequence stratigraphy of the Oligo-Miocene Asmari Formation in SW Iran

Depositional environment and sequence stratigraphy of the Oligo-Miocene Asmari Formation in SW Iran

The Oligo-/Miocene Qom Formation (Iran): evidence for an early Burdigalian restriction of the Tethyan Seaway and closure of its Iranian gateways

Oligocene and Early Miocene coral faunas from Iran: palaeoecology and palaeobiogeography

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