Decoupling biogeochemical records, extinction, and environmental change during the Cambrian SPICE event.
Decoupling biogeochemical records, extinction, and environmental change during the Cambrian SPICE event.
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DOI：
10.1126/sciadv.1602158
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发表时间：
2017-03
期刊：
影响因子：
13.6
通讯作者：
Shelton KL
中科院分区：
文献类型：
--
作者：
Schiffbauer JD;Huntley JW;Fike DA;Jeffrey MJ;Gregg JM;Shelton KL
局部沉积变化影响全球公认的地球化学事件的地质记录，如寒武纪SPICE。下古生代岩石中的几个正碳同位素漂移，包括突出的上寒武纪Steptoean正碳同位素漂移（SPICE），被认为反映了水圈生物圈系统的间歇性扰动。解释这些长期变化的模型是丰富的，但同位素信号的同步性和区域变化还没有得到很好的理解。在上寒武统中央密苏里州intrashelf盆地（美国）的古深度梯度的核心检查揭示了时间海侵，相依赖的性质的SPICE。虽然SPICE事件可能是一个全球性的信号，但它在岩石中的记录方式应该而且确实随着相和碳酸盐岩台地几何形状的变化而变化。我们呼吁一个范式的转变，以更好地约束相，地层和生物地层结构，并将这些观察应用到SPICE信号的幅度，地层范围和时间的变化，以及其他地球化学扰动，以阐明驱动海洋碳酸盐系统的复杂过程。
Local depositional variation affects geological recording of globally recognized biogeochemical events such as the Cambrian SPICE. Several positive carbon isotope excursions in Lower Paleozoic rocks, including the prominent Upper Cambrian Steptoean Positive Carbon Isotope Excursion (SPICE), are thought to reflect intermittent perturbations in the hydrosphere-biosphere system. Models explaining these secular changes are abundant, but the synchronicity and regional variation of the isotope signals are not well understood. Examination of cores across a paleodepth gradient in the Upper Cambrian central Missouri intrashelf basin (United States) reveals a time-transgressive, facies-dependent nature of the SPICE. Although the SPICE event may be a global signal, the manner in which it is recorded in rocks should and does vary as a function of facies and carbonate platform geometry. We call for a paradigm shift to better constrain facies, stratigraphic, and biostratigraphic architecture and to apply these observations to the variability in magnitude, stratigraphic extent, and timing of the SPICE signal, as well as other biogeochemical perturbations, to elucidate the complex processes driving the ocean-carbonate system.