Depositional Environment of Lower Permian Stone Corral Formation: ABSTRACT

Abstract

The Lower Permian Stone Corral Formation is a 5-8 ft thick unit of dolomitic limestone and shale in a sequence of red beds that crops out in south-central Kansas. It forms a good stratigraphic marker bed in the subsurface, where it consists mainly of anhydrite (the Cimmaron anhydrite) up to 100 ft thick. At outcrop, the formation is weathered and consists of 2 interfingering facies--a crinoidal-echinoidal grainstone (in the north) and a laminated mudstone (in the south). Both the grainstone and mudstone exhibit diagenetic alteration. The grainstone is composed of well-rounded allochems of crinoid and echinoid fragments with scattered ooids, sponge spicules, peloids, and possible foraminifers and ostracods. Layers of sponge spicules alternate with peloid or ooid layers. The mudstone facies has a clotted texture and has laminations defined by the occurrence of fenestral fabric and peloids. Dolomite occurring in the Stone Corral Formation is of secondary origin. The grainstone is interpreted as being lagoonal in origin, whereas the mudstone facies is interpreted as supratidal. The grumous (clotted) texture may indicate phreatic diagenesis. The absence of anhydrite on outcrop, where it was presumably leached by surface waters leaving the less soluble dolomite, is additional evidence for a regional disconformity above the unit on the eastern side of a large, shallow, evaporitic basin. End_of_Article - Last_Page 269------------