Bioclasts are skeletal fossil fragments of once living marine or land organisms that are found in sedimentary rocks laid down in a marine environment—especially limestone varieties around the globe, some of which take on distinct textures and coloration from their predominate bioclasts—that geologists, archaeologists and paleontologists use ...

These rocks are classified on the proportions of vitric, crystal (mineral), or lithic material they contain, for example, "vitric lithic ash," or "crystal vitric tuff."

Bioclastic limestones are as diverse as the fossils and fossil pieces that make them up. Some are dominated by sand-sized grains of finely broken up fossil debris. Others preserve whole communities of ancient life forms in remarkable detail.

Although many chemical and biochemical sedimentary rocks have clastic textures, some have crystalline textures, revealed by careful examination of the sample to see interlocking crystals. Chert & Flint = microcrystalline monomineralic (quartz) rocks. Texture in silt – shale sized clastic rocks depends on amount of compaction.

The combination of texture, peloidal grains, and fauna present suggests that the bioclastic-packstone-to-grainstone was deposited in a relatively normal marine, higher energy, and shallow environment.

Disarticulation of bioclasts is due to bioturbation or storm activity. The combination of abundant and fragmented marine fauna, a micritic matrix, and texture suggests that the bioclastic-mudstone-to-wackestone facies was deposited in an …

2021年6月1日 · Bioclastic sandy contourites are made up of shallow-marine winnowed bioclasts with a reversely- and normally-graded trend and represent lowstand contourite sands. The PCA in the two environments —showing a distinctive geochemical signal— allows for differentiation of the contourite deposits.

Reef (P1) displays the highest acoustic reflectivity, rough texture, and is associated with three-dimensional rocky features (Fig. 34.2A). Backscatter patterns P3 and P2 are well associated with bioclastic coarse sands with granules, nodules, and shells, while dunes and megarriples are widespread on these patterns ( Fig. 34.2F ).

2024年8月30日 · Bioclastic texture: Consists of fossilized remains of organisms, often seen in limestone. Crystalline texture : Forms from the precipitation of mineral crystals from solution. The size, shape, and arrangement of these fragments provide information about the rock's depositional environment.

2025年1月13日 · Bioclastic turbidites can create flow-associated sorting that in turn create more complex textures than their siliciclastic-only counterparts (Bornhold & Pilkey, Reference Bornhold and Pilkey 1971).