Publication Date:
2016-07-13
Description:
In recent years, considerable effort has been expended in studying trace and minor element chemistry of skeletal carbonate materials. These elements may be included in the skeleton in the following forms: 1, substitutes for calcium in the calcite or aragonite crystal lattice; 2, constituents of separate mineral phases; 3, surface adsorbed elements; or 4, constituents of organic compounds. The concentration of magnesium and strontium in carbonate skeletons is controlled by four major factors: 1, Water chemistry--Other factors being equal, the Mg/Ca and Sr/Ca ratios in skeletal material should be constant relative to those ratios in the water in which they formed. 2, Other environmental factors--Mg shows a strong positive correlation with temperature in calcitic skeletons. Lesser temperature and salinity effects have been noted for Sr in calcites and aragonites and possibly Mg in aragonite. 3, Mineralogy--Calcite is generally high in Mg and low in Sr relative to aragonite. 4, Physiology of the organisms--In general, the phylogenetically more advanced forms have lower Mg and Sr values. Skeletal chemistry may also vary between genera and families within a given major group. The mechanisms of physiological control of Mg and Sr are not understood but "isolation" of the calcification site and growth rate may be involved. Among the applications of skeletal chemical data are uses in studying carbonate sediment chemistry, diagenesis of fossils and carbonate rocks, paleoecologic interpretations, geochemical cycles, and history of sea water chemistry.
Type:
Article
,
PeerReviewed
Format:
text
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