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The Goat Seep "reef" constitutes the lower third of Guadalupian shelf-edge deposits but has been studied less than the Capitan because of outcrop inaccessibility and pervasive dolomitization. The Goat Seep is not simply an older Capitan but differs in aspects of morphology, biota, and cements.
Field studies reveal that the Capitan overlies Goat Seep without an apparent depositional break and that this contact is not the dolomite-limestone transition previously mapped. Instead, several hundred meters of the oldest Capitan are dolomitic. The Shattuck Sandstone extends across the shelf edge and into the foreslope, providing a convenient marker for the Goat Seep-Capitan contact. The shelf-to-basin relief of the Goat Seep (300 to 400 m) is similar to the older Capitan. The upper shelf-edge Goat Seep consists largely of high-angle (25 to 30°) foreslope deposits of autochthonous and allochthonous carbonate rocks (primarily wackestones) and minor siliciclastics. The Goat Seep, in contrast to the Capitan, has little high-angle, shelf-edge, massive facies (0 to 10 m compared to 00 to 200 m). Deeper, lower angle, toe-of-slope carbonate deposits are largely allochthonous, consisting of channelized debris flows and other gravity-flow deposits.
Goat Seep biota, consisting largely of calcareous sponges, with some bryozoans, brachiopods, corals, echinoderms, and Tubiphytes resemble Capitan biota. The Goat Seep lacks the abundant calcareous algae of the upper Capitan.
Cement crusts, present as pore linings in wackestones and as pockets of closely packed, broken, platelike grains, form a distinctive lithology in the youngest Goat Seep and oldest Capitan. These cements have an inferred submarine origin and probably formed an inorganic framestone on or near the seafloor.
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