Specimen: 2014-048
This is a fossiliferous limestone. The limestone is grain supported with a cement matrix that is near equal parts sparite and micrite. The patchy texture of the cement matrix suggests some amount of neomorphism. Allochems constitute about 80 percent of slide area. These criteria indicate the limestone is best described as a packstone. Allochem composition is about 55 percent peloid, 40 percent ooid, and 5 percent bioclast. These estimates and the degree of sorting indicate this limestone is an unsorted oosparite or oomicrite. Micritic envelopes are pronounced. Identifiable bioclast maximum dimensions are as follows: bivalve 3.2 mm, ostracod .6 mm, univalve mollusk .6 mm, and calcispheres .15. Bivalve fragments are the most common with fragments completely replaced by consertal calcite. Larger fossils than those captured on this slide are macroscopically visible in the hand sample. The size range of ooids and peloids is similar with a maximum near .4 mm, a minimum of .1 mm, and a modal range around .3 mm. Collophane is also present and has a maximum size near .8 mm. Iron hydroxides and opaque grains are far less than 1 percent of slide area. Extant voids constitute far less than 1 percent of slide area and are mostly vug like with a maximum dimension near .75 mm. Given the degree of allochem preservation and spacing, lithification likely occurred prior to compaction.
MP 7/21/2015