Abstract
Abstract The abundance of dolomitic strata in the geological record contrasts with the general rarity of locations where dolomite forms today, a discrepancy that has long posed a problem for their interpretation. Recent culture experiments show that dolomite can precipitate at room temperature, raising the possibility that many ancient dolomites may be of syngenetic origin. We compiled a large geodata set of secular variations in dolomite abundance in the Phanerozoic, coupled with compilations of genus richness of marine benthic invertebrates and sulfur-isotope variations in marine carbonates. These data show that dolomite abundance is negatively correlated to genus diversity, with four dolomite peaks occurring during mass extinctions. Dolomite peaks also correspond to the rapid increase in sulfur-isotope composition (δ34S), an indicator of enhanced sulfate reduction, in anoxic oceans. These results confirm that variations in dolomite abundance during the Phanerozoic were closely linked with changes in marine benthic diversity, with both in turn related to oceanic redox conditions.
Highlights
Dolomite is a form of rhombohedral carbonate mineral that is common in carbonate successions in the geological record, and it often forms dolostones, which can be important hydrocarbon reservoirs (e.g., Petrash et al, 2017)
Research on dolomite formation can be divided into three stages (Burns et al, 2000): (1) the first stage (1800–1900 CE) was marked by the study of synthesis of dolomite at high temperature (250 °C); (2) the second stage (1900–1995) saw discoveries of dolomite in modern environments and the development of new models to explain dolomite formation; and (3) the third stage (1995–present) was characterized by series of experiments that showed dolomite could be synthesized at low temperatures in the presence of microbes
We aimed to address this problem by compiling a large geodata set to show the secular variations in dolomite abundance during the Phanerozoic and to investigate factors that correlate with dolomite fluctuations
Summary
Dolomite is a form of rhombohedral carbonate mineral that is common in carbonate successions in the geological record, and it often forms dolostones, which can be important hydrocarbon reservoirs (e.g., Petrash et al, 2017). We aimed to address this problem by compiling a large geodata set to show the secular variations in dolomite abundance during the Phanerozoic and to investigate factors that correlate with dolomite fluctuations. Previous research has linked dolomite abundance in the Phanerozoic Eon with fluctuations in atmospheric oxygen (Burns et al, 2000), sulfur-isotope composition (Burns et al, 2000; Li et al, 2018), and global eustasy (Sibley, 1991). The lack of a large dolomite geodata set has made evaluation of these and other links uncertain
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