FACTORS INFLUENCING THE MINERALOGY OF CARBONATE SEDIMENTS

• Main Author: Keith E. Chave
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Planktonic foraminifera
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.492.8100; http://www.aslo.org/lo/toc/vol_7/issue_2/0218.pdf

The mineralogy of carbonate sediments from Campechc Bank and Bermuda has been studied by USC of X-ray diffraction techniques. The sediment mineralogy appears to be mainly controlled by the skeletal mineralogy and size of organisms living locally. Selective physical destruction and transport and selcctivc solution of more soluble skeletal elements appear to exert an influcncc on scdimcnt mineralogy. Reef and near-reef sediments contain the largest concentrations of high-magnesium calcite, largely due to the presence of corallinc algae such as Lithothnmnium. Lagoonal scdimcnts contain the most aragonite, and also contain abundant fragments of the green algae, Hdimeda. Shelf, slope, and deep-water carbonates arc rich in low-magnesium calcite, probably due to the prcsencc of planktonic Foraminifera and algae. The effects of non-biological processes on scdimcnt mineralogy can bo seen in the distribution of mineralogies among the diffcrcnt size fractions of the sediment. The most prominent feature of this is the regular increase in mineral stability-and associated decrease iu mineral solubility-from the coarse to the fine fractions of sediments from a wide range of environments. It appears that in some areas the more soluble mineralogies are dissolved from the fine fractions of the sediments.