041819

Grainstone composed almost exclusively of Parafavreina, a fecal pellet made by burrowing shrimp. This deposit is almost identical to modern accumulations of fecal pellets made by related burrowing-shrimp.This thin section was stained with Alizarin red S, staining calcite pink. White particles are quartz silt grains.. Light pink areas are calcite cement crystals filling original open spaces among the pellets. Jurassic Smackover Formation, Alabama, image 2.5 mm wide.

The photos of Parafavreina that I have been posting were taken in the process of preparing this scientific article:

Rindsberg, A. K., and Kopaska-Merkel, D. C., 2013 , Parafavreina ziczac isp. nov., a crustacean microcoprolite from the Upper Jurassic (Oxfordian) Smackover Formation of Alabama, U.S.A., Alabama Museum of Natural History Bulletin 31, v. 2. p. 74-93.

I have PDF copies of the article if anyone is interested.

041719d

Dolomite (gray) partially replacing calcite (pink) in a mixed-particle grainstone cemented with marine cement crystals (light pink). Particle in the center is a shrimp fecal pellet. 13,000 feet below the surface, Jurassic Smackover Formation, thin section photomicrograph, field of view 2.5 mm wide

041119b

Clotted thrombolite with large cylindrical fecal pellets of burrowing shrimp, Jurassic smackover formation, Alabama, thin-section photomicrograph.

041019c

Fecal-pellet grainstone dominated by the distinctive pellets of callianassid shrimp (the larger particles). Dolomitized Jurassic Smackover Formation, Alabama, thin-section photomicrograph. The pallets are trace fossils called Parafavreina ziczac. Generally, no fossils of the shrimp themselves are preserved, but their distribution is easily recognized from their pellets.

022119b

Core of the Smackover Formation in West Appleton Field, south Alabama. Microbial boundstone (lower half) overlain by laminated carbonate sand consisting primarily of fecal pellets of burrowing shrimp (upper half). Dime for scale.