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Title: Early-mid-Cretaceous evolution in Tethyan reef communities and sea level

Abstract

The replacement of corals by rudists in Early Cretaceous reefal communities spanned a 30-m.y. period when sea level rose and drowned continental shelves. During this time corals formed communities in the deeper parts of reefs and rudists occupied the shallow, high-energy habitats. By Aptian time rudists dominated reefs that fringed interior shelf basins and corals formed reefs with rudists on the outer shelf margins. By late Albian coral communities had virtually disappeared, presumably because of complex environmental changes and cycles of organic productivity. Two important events of eustatic sea level rise are represented by unconformities separating carbonate depositional sequences on the Arabian platform that correlate with sequence boundaries on the Gulf Coast platform. Graphic correlation techniques test the synchroneity of these events. A composite standard time scale dates these sea level rises at 115.8 Ma and 94.6 Ma; a third, intra-Albian event at 104.3 Ma is present in many places and may also be eustatic. Associated with these sea level rises were apparent changes in ocean water chemistry as evidenced by changes in isotopes and trace elements, where diagenetic effects can be discounted. During this time the climate became more humid and atmospheric CO/sub 2/ increased. The concomitant environmental changesmore » in the oceanic conditions presumably stressed the deeper coral communities on reefs. The emergence of rudists as reef contributors had a profound effect on Late Cretaceous depositional conditions and the development of hydrocarbon reservoirs.« less

Authors:
Publication Date:
Research Org.:
Amoco Production Co., Tulsa, OK (USA)
OSTI Identifier:
5796958
Alternate Identifier(s):
OSTI ID: 5796958
Report Number(s):
CONF-880301-
Journal ID: CODEN: AABUD
Resource Type:
Conference
Journal Name:
AAPG Bull.; (United States)
Additional Journal Information:
Journal Volume: 72:2; Conference: Annual meeting of the American Association of Petroleum Geologists, Houston, TX, USA, 20-23 Mar 1988
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; CRETACEOUS PERIOD; REEFS; DEPOSITION; CARBON DIOXIDE; CORALS; DIAGENESIS; PALEOCLIMATOLOGY; SEA LEVEL; TRACE AMOUNTS; WATER CHEMISTRY; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMISTRY; CNIDARIA; GEOLOGIC AGES; GEOLOGIC STRUCTURES; LEVELS; MESOZOIC ERA; OXIDES; OXYGEN COMPOUNDS; PALEONTOLOGY 020200* -- Petroleum-- Reserves, Geology, & Exploration

Citation Formats

Scott, R.W. Early-mid-Cretaceous evolution in Tethyan reef communities and sea level. United States: N. p., 1988. Web.
Scott, R.W. Early-mid-Cretaceous evolution in Tethyan reef communities and sea level. United States.
Scott, R.W. Mon . "Early-mid-Cretaceous evolution in Tethyan reef communities and sea level". United States.
@article{osti_5796958,
title = {Early-mid-Cretaceous evolution in Tethyan reef communities and sea level},
author = {Scott, R.W.},
abstractNote = {The replacement of corals by rudists in Early Cretaceous reefal communities spanned a 30-m.y. period when sea level rose and drowned continental shelves. During this time corals formed communities in the deeper parts of reefs and rudists occupied the shallow, high-energy habitats. By Aptian time rudists dominated reefs that fringed interior shelf basins and corals formed reefs with rudists on the outer shelf margins. By late Albian coral communities had virtually disappeared, presumably because of complex environmental changes and cycles of organic productivity. Two important events of eustatic sea level rise are represented by unconformities separating carbonate depositional sequences on the Arabian platform that correlate with sequence boundaries on the Gulf Coast platform. Graphic correlation techniques test the synchroneity of these events. A composite standard time scale dates these sea level rises at 115.8 Ma and 94.6 Ma; a third, intra-Albian event at 104.3 Ma is present in many places and may also be eustatic. Associated with these sea level rises were apparent changes in ocean water chemistry as evidenced by changes in isotopes and trace elements, where diagenetic effects can be discounted. During this time the climate became more humid and atmospheric CO/sub 2/ increased. The concomitant environmental changes in the oceanic conditions presumably stressed the deeper coral communities on reefs. The emergence of rudists as reef contributors had a profound effect on Late Cretaceous depositional conditions and the development of hydrocarbon reservoirs.},
doi = {},
journal = {AAPG Bull.; (United States)},
number = ,
volume = 72:2,
place = {United States},
year = {1988},
month = {2}
}

Conference:
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