Abstract

The Flippen Limestone of central Jones County, Texas, is one of a series of Virgilian-Wolfcampian limestones reflecting the characteristic cyclic deposition of late Pennsylvania and early Permian sediments on the Eastern shelf of the Midland Basin.

Data obtained from cores indicates that the Flippen Limestone was subaerially exposed to the effects of meteoric waters during a regressive phase of the sea. Paleostream systems developed, and the Flippen was leached and eroded as streams meandered westward from the Ouachita Uplift toward the subsiding Midland Basin.

There are at least four depositional facies within the Flippen Limestone. A calcarenite facies may be subdivided into a shallow marine, medium to high energy grainstone lithotype, or a low energy, shallow marine, packstone lithotype. A pelletal-breccia facies represents a shallow marine, restricted depositional environment. The pelletal limestone was brecciated upon exposure to meteoric waters in a supratidal environment. A rounded grain facies composed of micrite mud balls and fossil fragments set in a matrix of blocky calcite spar is indicative of a shallow marine, medium to high energy environment. Nodular limestone representing a low energy, nearshore marine environment is the uppermost depositional facies recognized in the sequence.

Diagenetic processes are responsible for both creation and destruction of porosity and permeability in the Flippen Limestone. Secondary pores in the form of pinpoint vugs, solution channels, solution-enlarged breccia porosity, and moldic porosity, are the result of subaerial exposure and leaching by percolating meteroic waters in a vadose environment.

Primary porosity is mostly absent due to cementation by blocky spar and microspar. Much secondary porosity (most notably solution-enlarged breccia porosity) has been occluded by white, coarse crystalline, late diagenetic, sparry dolomite.