Facies-Dependent Diagenesis of Shelf-Margin Sandstones and Siltstones, Yates Formation, Northern Margin of Delaware Basin: ABSTRACT

Abstract

Shelf-margin sandstones and siltstones of the Permian (late Guadalupian) Yates Formation, continuously cored in the Gulf PDB-04 research well of the northern margin of the Delaware basin, have varying textures, compositions, and diagenetic histories. Gray, dolomitic, quartzose, very fine to fine-grained sandstones occur in the lower part of the formation; dark red (FeO/sub 2/-stained detrital clay-bearing), anhydritic, subarkosic to arkosic, very fine-grained sandstones/siltstones occur in the upper portions. Stratigraphic relations, associated carbonates, and ichnofossils suggest that the gray sands were deposited seaward of a pisolite shoal complex in an intertidal to marginally subtidal setting, whereas the overlying red clastics accumulated along the crest of the shoal in a supratidal environment. This interpretation is congruent with the progradational history of the Yates Formation as established by outcrop and subsurface studies. Depositionally updip sandstones, studied from outcrop and other wells, show that the source sandstones for the gray and red sandstones in the PDB-04 well have relatively uniform depositional textures and mineralogies (silty, fine grained, lithic, subarkoses to arkoses). This strongly suggests that the variations seen in the core are due to facies-dependent diagenesis.