About This Item
- Full text of this item is not available.
- Abstract PDFAbstract PDF(no subscription required)
Share This Item
The AAPG/Datapages Combined Publications Database
AAPG Bulletin
Abstract
Volume:
Issue:
First Page:
Last Page:
Title:
Author(s):
Article Type:
Abstract:
Well cuttings and core samples from 17 wells in El-Morgan field were studied for grain-size distribution, degree of roundness, and feldspar content. The sandstones are Miocene and generally are arkose or subarkose. Mechanical analysis indicates that the sand mode achieved good sorting in a high-energy beach environment, and then was transported en masse by strong waves and currents to a neritic environment where it became mixed with finer sand and clay. The sandstones are leptokurtic and positive skewed indicating a nearby source area. Study of roundness of the sand grains reveals a mixed source, mainly plutonic, with minor contributions from a preexisting sedimentary source, presumably a Cretaceous or Nubian sandstone.
Maps showing the variation in average grain size, feldspar content, and percent of sand in the formation, clearly indicate a source area south and southwest of the field. It is believed to be the nearby Zeit Range. The lack of feldspar alteration is attributed to rapid erosion as a result of the high relief attained by large-scale block faulting in pre-Miocene and early Miocene times and to conditions of extreme aridity.
The sands were deposited from traction currents. The bottom topography of the Miocene sea controlled the amount of turbulence and determined the size, shape, and distribution of the sands.
End_of_Article - Last_Page 337------------