2007 GSA Denver Annual Meeting (2831 October 2007)
Paper No. 118-13
Presentation Time: 1:30 PM-5:30 PM


HUSSAIN, Mahbub, Tybrin Corporation, Edwards Airforce Base, California, Los Angeles, CA 93524-6630, AL-SHAIBANI, Abdulaziz M., Earth Sciences, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia, shaibani@kfupm.edu.sa, and KHANDAKER, Nazrul I., Natural Sciences Department, Geology Discipline, York College of CUNY, 94-20 Guy R. Brewer Blvd, Jamaica, NY 11451

The influence of water chemistry in carbonate cement mineralogy, more specifically, Mg/Ca ratio in crystal (polymorph) habit has been demonstrated by laboratory experiments. Bulk studies have indicated that calcite growth is inhibited through either step-blocking by Mg2+ adsorption and slow dehydration or enhanced mineral solubility associated with Mg2+ incorporation. Based on several studies, meteoric water, generally low in Mg/Ca ratio, would favor formation of equant crystals of calcite. On the other hand, marine waters marked by high Mg/Ca ratios would produce the elongate (c-axis) aragonite crystals. The southern shorelines of the Arabian Gulf stretching from the backdune/supratidal to the subtidal areas are characterized by systematic increase in the Mg/Ca ratio in pore-water. A scanning electron microscopic (SEM equipped with EDX) study of the carbonate sediments from Al-Ukair lagoon systems, south of Dammam, the capital of Eastern Province of Saudi Arabia, shows systematic variations in calcium carbonate mineralogy in response to the pore-water chemistry represented by different shoreline sub-environments. Considering the fact that the composition and crystal habit of the primary carbonate minerals have profound effects on the diagenetic evolution and reservoir quality of carbonate rocks and carbonate-cemented clastic rocks, if preserved in geologic records, such mineralogy should provide a better understanding of reservoirs deposited in similar settings.

2007 GSA Denver Annual Meeting (2831 October 2007)
General Information for this Meeting
Session No. 118--Booth# 186
Involvement in Geological Research: Close Collaboration among the Faculty and Undergraduate and K12 Students (Posters)
Colorado Convention Center: Exhibit Hall E/F
1:30 PM-5:30 PM, Monday, 29 October 2007

Geological Society of America Abstracts with Programs, Vol. 39, No. 6, p. 328

© Copyright 2007 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.