THE RECORD OF CARBON, OXYGEN, SULFUR, AND STRONTIUM ISOTOPES AND TRACE ELEMENTS IN LATE PALEOZOIC BRACHIOPODS (STABLE, PERMO-CARBONIFEROUS, OCEANOGRAPHY, MICROSTRUCTURE)

Chemical diagenesis of marine carbonate sediments should result in disruption of original textural characteristics and in trends toward re-equilibration of trace elements and isotopes with diagenetic fluids. Therefore, textural, elemental, and isotopic variations can be used to determine the extent of post-depositional alteration of carbonate components.; Analyses of well-preserved brachiopods indicates an apparent "vital" effect on the uptake of Sr and Mg into their shells. The concentration of Mn and Fe in brachiopod shells is controlled by the extent of diagenetic alteration.; The oxygen and carbon isotopic records of components in Paleozoic limestones show generally good internal consistency. However, significant discrepancies were noted between results on the different components. Well-preserved brachiopods appear to be the best choice for estimating original isotopic compositions in Paleozoic limestones.; The results from carbon and oxygen isotopic composition from all components indicate a general decrease in (delta)('18)O and (delta)('13)C in geologically older material. Oxygen isotopic results suggest an important positive shift in (delta)('18)O during the Early Carboniferous, whereas the carbon isotope trend shows a major positive shift ((DBLTURN)2-3%) during the Mid-Carboniferous.; Sr isotopic analyses of well-preserved portions of Permo-Carboniferous brachiopods collected globally confirm the general shape of the Sr isotope age curve established by previous workers for this time interval. The Sr isotopic composition in the unaltered portions of calcitic megafossils has potential as a stratigraphic tool.; The few sulfur isotopic analyses of brachiopods agree with the general shape of the (delta)('34)S curve from evaporites. Because of the relative ease with which limestones can be stratigraphically dated compared to evaporites, data from brachiopods can potentially yield a more complete (delta)('34)S age curve.; Comparison of the (delta)('18)O and ('87)Sr/('86)Sr curves for the Paleozoic suggests sea-floor alteration dominated the ('18)O content of sea water, whereas weathering on continents appears to affect more significantly the ('87)Sr/('86)Sr ratio in sea water. Comparison of the secular variation of carbon and sulfur isotopes during the Permo-Carboniferous suggest a decoupling of the carbon and sulfur redox balance which may have produced a net flux of O(,2) to the atmosphere and a net reduction of pCO(,2) of the atmosphere.