allochem


Also found in: Wikipedia.

allochem

[′a·lō‚kem]
(geology)
Sediment formed by chemical or biochemical precipitation within a depositional basin; includes intraclasts, oolites, fossils, and pellets.
Mentioned in ?
References in periodicals archive ?
Clast type 2 has an allochem suite that is almost completely dominated by strongly aligned disarticulated and abraded thin shelled bivalves (IPosidonia) and small quantities of fine micropeloids that appear light grey in PPL.
The microfacies is characterized by skeletal allochems which are the only allochemical constituents marked by moderate diversity of organisms with allochem to micrite ratio of 7:3.
These microfacies have been studied on the basis of orthochem and allochem elements, their percentages, and their texture in the stratigraphy section [19].
Additional allochem particles include pelloids, some spherical single-walled calcispheres, and rare microcrinoid ossicles.
The microfacies analysis details the allochem matrix textural features and fossils content of the lithofacies (WF1-WF9).
The allochem and matrix ratio is3:7, according to visual estimation, the average relative abundance of various faunal and floralconstituents is Lockhartia (15%), Operculina(1%) and Milliolid up to (7%).
allochem type, composition, texture, sedimentary structures and rock types), three microfacies and five sub microfacies are recognized (Fig.
Bioclast is the dominant allochem type which includes; sponge spicules (3 Percent), ostracods (3 Percent), intraclasts (1 Percent) and pellet (3 Percent).
This stage is composed of limestone with abundant larger foraminifera, algae is the second dominant allochem type.
On the basis of detailed field and petrographic characteristics, four microfacies with distinct textures, allochem types, fossil contents and sedimentary structures are identified and interpreted.
In classifying limestone, various attempts have been made, notable among them are the classification scheme of Folk (1959,1962) which was based on three components: allochems, matrix and cements.