Diagenetic alteration in low-Mg calcite from macrofossils: a review
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چکیده
منابع مشابه
Microstructural and geochemical perspectives on planktic foraminiferal preservation: Glassy versus Frosty
[1] In recent years it has become apparent that the ‘‘cool tropic paradox’’ of Paleogene and Cretaceous ‘‘greenhouse’’ climates arises because of the diagenetic alteration of tropical planktic foraminiferal calcite near the seafloor, yielding artificially high dO values. Because the Mg/Ca compositions of foraminiferal and inorganic calcite are thought to be quite different, Mg/Ca measurements s...
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Interand intra-specimen variability masks reliable temperature control on shell Mg/Ca ratios in laboratory and field cultured Mytilus edulis and Pecten maximus (bivalvia) P. S. Freitas, L. J. Clarke, H. A. Kennedy, and C. A. Richardson School of Ocean Sciences, College of Natural Sciences, Bangor University, UK Departamento de Geologia Marinha, INETI, Portugal Received: : 29 November 2007 – Acc...
متن کاملCenozoic deep-Sea temperatures and global ice volumes from Mg/Ca in benthic foraminiferal calcite
A deep-sea temperature record for the past 50 million years has been produced from the magnesium/calcium ratio (Mg/Ca) in benthic foraminiferal calcite. The record is strikingly similar in form to the corresponding benthic oxygen isotope (delta(18)O) record and defines an overall cooling of about 12 degrees C in the deep oceans with four main cooling periods. Used in conjunction with the benthi...
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Using three different microscopy techniques (epifluorescence, electronic and atomic force microscopy), we showed that high-Mg calcite grains in calcifying microbial mats from the hypersaline lake "La Salada de Chiprana", Spain, contain viruses with a diameter of 50-80 nm. Energy-dispersive X-ray spectrometer analysis revealed that they contain nitrogen and phosphorus in a molar ratio of ~9, whi...
متن کاملUse of Clumped-isotope Thermometry to Constrain the Crystallization Temperature of Diagenetic Calcite
We describe an approach to estimating the crystallization temperatures of diagenetic calcites using clumped-isotope thermometry, a paleothermometer based on the C–O-bond enrichment in carbonates. Application of this thermometer to calcified gastropod shells and calcite cements in an early Eocene limestone from the Colorado Plateau reveals a record of calcite precipitation and replacement at tem...
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ژورنال
عنوان ژورنال: Geological Quarterly
سال: 2015
ISSN: 1641-7291
DOI: 10.7306/gq.1217