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Mahbub Hussain1, Lameed O. Babalola1, Mustafa M. Hariri2
(1) King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
(2) King Fahd University Of Petroleum and Minerals, Dhahran, Saudi Arabia

Abstract: Provenance of the Lower Paleozoic Wajid Sandstone, Southeastern Margin of the Arabian Shield: A Geochemical and Petrographic Approach

The Cambro-Ordovician age Wajid Sandstone at the southeastern margin of the Arabian Shield is represented by several small isolated outliers, stretching over an area of approximately 25,000 square kilometers. This coarse-grained, highly ferruginous, cross-bedded, mineralogically matured sandstone formation overlies the peneplained Precambrian basement comprising of metamorphic and igneous rocks.

A geochemical study involving trace element distribution of the samples collected from three outliers in Asir Province, and multivariate statistical analyses of the data suggest felsic igneous terrains located southwest of the study area (in Yemen) as the dominant source for these sediments. The southwesterly provenance is also indicated by the paleocurrent data of the cross-bedded sandstone units. The deduced source terrains and dispersion patterns of the Wajid Sandstone are not consistent with that of the younger clastic sequences in the area which show consistent progradation of the sediments from the highlands of the shield area in the west to the east. Minor contributions from the mafic igneous and low-grade metamorphic rocks in the vicinity were also recognized.

Heavy mineral distribution and clay mineralogy of the sediments corroborate the conclusions based on the trace element geochemistry. The geochemical and petrographical data also suggest intensive post-burial weathering of the sediments as a possible explanation for the mineralogical maturity of the sediments in the area.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana