This document is the summary of a research project conducted at the UNOCAL Research Center— Basin Analysis Group between 1989 and 1994.  The impetus for this research work was due to doubts about the prevailing diagenetic theory to account for the occurrence and distribution of kaolinite matrix clay found in some petroleum bearing sandstone reservoirs in the San Joaquin Basin of California such as the Gatchell Formation (Middle Eocene).

The Ione Formation depositional system was a convenient fluvial model to study the mineralogy and petrology of tropical river systems that operated during globally warm and humid conditions in the ancient past.  The Ione system is a good example of river systems that erode mature kaolinitic tropical soils in their upper reaches and transport substantial volumes of clayey materials in their sediment load.

Research work on this topic has been continuous from the time of this publication to the present time.  While the fundamental conclusions posed in this document are still valid, some details require modification due to subsequent discoveries that have come about in the course of later work.  A discussion of these corrections will be included with this document in the near future.

The format for this document was altered from its original form to conserve paper if printed; i.e.., this version is presented in single-spaced format.

Wood, James L., 1994, A Re-evaluation of the Origin of Kaolinite in the Ione Depositional System (Eocene), Sierra Foothills, California;  M. S. thesis document, California State University at Los Angeles.

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