Chemostratigraphy and Biostratigraphy of Devonian, Carboniferous and Permian Sediments Encountered in Eastern Saudi Arabia

Chemostratigraphy is a correlation technique involving the application of inorganic geochemical data to define correlative chemozones and boundaries between wells. The present study utilizes the technique to correlate Devonian, Carboniferous and Permian sedimentary sequences encountered in six study wells, located in eastern Saudi Arabia. Data for 50 elements were acquired from 850 core and cuttings samples using ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometry) and ICP-MS (Inductively Coupled Plasma-Mass Emission Spectrometry) analytical instruments. Hierarchical schemes were developed for sandstone and mudrock lithologies using carefully selected profiles plotted for ‘key’ elements and elemental ratios. Variations in these elements/ratios are largely dependent on changes in sediment source/provenance. By comparing the chemostratigraphic schemes with an existing scheme based on palynology, it was possible to identify formation boundaries and to produce a much higher level of resolution than by using lithostratigraphy. Such a multidisciplinary approach proved extremely useful in correlating the Jauf Formation, occurring towards the base of each study section. It was possible to use the biostratigraphic and chemostratigraphic data to determine that the sandstones of this formation were deposited in the form of isolated ‘pods’, rather than laterally correlative layers, a fact that is supported by the available seismic data.