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Title: Carbonate-evaporite cycles in the Miocene to Holocene of Abu Dhabi, United Arab Emirates

Abstract

The coastal sabkhas of the United Arab Emirates provide a Holocene analog for the study of evaporite formation. Carbonate-evaporite sequences are common throughout geologic history and, in the Arabian Gulf region in particular, create the reservoir-seal relationship of some of the most prolific hydrocarbon reservoirs in the world. Detailed core description, thin section study and geochemical analysis of Miocene to Holocene cores from the sabkha of Abu Dhabi have been performed in order to characterize modern sabkha diagenetic patterns. Two primary lithologies, dolomite and anhydrite were identified and subdivided into lithofacies. Based on these lithofacies, deposition is interpreted to have occurred in shallow open marine, lagoonal, tidal channel, tidal/algal flats and supratidal sabkha settings. The primary diagenetic effects are dolomitization, anhydritc formation and leaching. As anhydrite precipitated (in the form of gypsum), the Mg:Ca ratio increased to the point where rapid dolomitization of original limestone occurred. Leaching was pervasive, as subaerial exposure led to the formation of moldic porosity in dolomitized packstones and grainstones. Dolomitic cements in these pores, and leached zones in some of these crystals suggests that leaching continued after dolomitization. By comparing the Holocene sabkha sediments to ancient ones, insight may be gained into the extent ofmore » dolomilization both with depth and distance for in the high water mark, the zonation of the stratigraphy from upper supratidal to shallow shelf, the preservation potential of algal mats after burial, the compaction effects after shallow burial, and other diagenetic alterations.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
127737
Report Number(s):
CONF-950995-
Journal ID: AABUD2; ISSN 0149-1423; TRN: 95:005942-0295
Resource Type:
Journal Article
Resource Relation:
Journal Name: AAPG Bulletin; Journal Volume: 79; Journal Issue: 8; Conference: International conference and exhibition of the American Association of Petroleum Geologists, Inc.: managing change at the turn of the century, Nice (France), 10-13 Sep 1995; Other Information: PBD: Aug 1995
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; 58 GEOSCIENCES; UNITED ARAB EMIRATES; STRATIGRAPHY; RESERVOIR ROCK; DIAGENESIS; POROSITY; EVAPORITES; CARBONATE ROCKS

Citation Formats

Whittle, G.L., Alsharhan, A.S., and Takezaki, H. Carbonate-evaporite cycles in the Miocene to Holocene of Abu Dhabi, United Arab Emirates. United States: N. p., 1995. Web.
Whittle, G.L., Alsharhan, A.S., & Takezaki, H. Carbonate-evaporite cycles in the Miocene to Holocene of Abu Dhabi, United Arab Emirates. United States.
Whittle, G.L., Alsharhan, A.S., and Takezaki, H. Tue . "Carbonate-evaporite cycles in the Miocene to Holocene of Abu Dhabi, United Arab Emirates". United States.
@article{osti_127737,
title = {Carbonate-evaporite cycles in the Miocene to Holocene of Abu Dhabi, United Arab Emirates},
author = {Whittle, G.L. and Alsharhan, A.S. and Takezaki, H.},
abstractNote = {The coastal sabkhas of the United Arab Emirates provide a Holocene analog for the study of evaporite formation. Carbonate-evaporite sequences are common throughout geologic history and, in the Arabian Gulf region in particular, create the reservoir-seal relationship of some of the most prolific hydrocarbon reservoirs in the world. Detailed core description, thin section study and geochemical analysis of Miocene to Holocene cores from the sabkha of Abu Dhabi have been performed in order to characterize modern sabkha diagenetic patterns. Two primary lithologies, dolomite and anhydrite were identified and subdivided into lithofacies. Based on these lithofacies, deposition is interpreted to have occurred in shallow open marine, lagoonal, tidal channel, tidal/algal flats and supratidal sabkha settings. The primary diagenetic effects are dolomitization, anhydritc formation and leaching. As anhydrite precipitated (in the form of gypsum), the Mg:Ca ratio increased to the point where rapid dolomitization of original limestone occurred. Leaching was pervasive, as subaerial exposure led to the formation of moldic porosity in dolomitized packstones and grainstones. Dolomitic cements in these pores, and leached zones in some of these crystals suggests that leaching continued after dolomitization. By comparing the Holocene sabkha sediments to ancient ones, insight may be gained into the extent of dolomilization both with depth and distance for in the high water mark, the zonation of the stratigraphy from upper supratidal to shallow shelf, the preservation potential of algal mats after burial, the compaction effects after shallow burial, and other diagenetic alterations.},
doi = {},
journal = {AAPG Bulletin},
number = 8,
volume = 79,
place = {United States},
year = {Tue Aug 01 00:00:00 EDT 1995},
month = {Tue Aug 01 00:00:00 EDT 1995}
}