MILLIKEN, MICHAEL S.¹ and JOHN F. CASEY^2
1Amoco Canada, Calgary, Alberta
²University of Houston, Geosciences, Houston, TX

Abstract: Chemostratigraphy of Cores DB-01 and DB-02 Delaware Basin, Culberson County, Texas

Surface cores DB-01 and DB-02 penetrate the Permian Cherry Canyon and Brushy Canyon Formations. Core DB-01 is interpreted to be a channel deposit of a submarine canyon Core DB-02, 1500 feet away perpendicular to the channel, is interpreted to be an overbank deposit of the DB-01 channel. The purpose of this study is to demonstrate the viability of using chemostratigraphy to correlate between these two cores each containing coeval deposits of very different depositional environments. Immobile trace element ratios, specifically rare earth elements (REE), appear to be the most useful for these correlations. The most useful ratios for correlations were found to be La/Yb, Gd/Yb and La/Sc. La/Yb and Gd/Yb are light to heavy REE and middle to heavy REE ratios respectively. Rare earth elements are believed to be relatively immobile in the sedimentary environment with the exception of Ce. Changes in REE ratios are thought to be related primarily to changes in sediment source terrane. REE are concentrated in heavy minerals which are highly resistant to aqueous dissolution. Furthermore, REE do not easily substitute in common sedimentary rocks. Thus, correlations from one depositional environment to another which both have the same source terrane are possible. This technique could be used in situations where traditional correlation techniques prove problematic. For instance, defining a sequence boundary in a shale on shale contact or correlating sandstones in a complex structural and depostional setting.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas