The Cambrian Drumian carbon isotope excursion (DICE) in the Great Basin, western United States
The Cambrian Drumian carbon isotope excursion (DICE) in the Great Basin, western United States
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DOI：
10.1016/j.palaeo.2010.07.001
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发表时间：
2010-10
期刊：
影响因子：
--
通讯作者：
R. Howley;G. Jiang
中科院分区：
文献类型：
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作者：
R. Howley;G. Jiang
寒武纪系列 3（原中寒武统）德鲁姆阶的全球边界层型剖面和点（GSSP）是由美国犹他州德拉姆山深水惠勒组中不生三叶虫 Ptychagnostus atavus 的首次出现基准（FAD）定义的。在大盆地（美国）、中国和斯堪的纳维亚半岛，P. atavus 的 FAD 与海侵和称为德鲁米安碳同位素偏移 (DICE) 的负碳同位素偏移有关。然而，P. atavus的FAD、海平面变化和DICE之间的关系是暂时的，主要是由于浅水剖面生物地层数据的缺乏限制了深水和浅水化学地层剖面之间的相关性。一项横跨犹他州西部和内华达州南部台地到盆地横断面的综合层序和化学地层学研究表明，DICE 在地层上位于 P. atavus 的 FAD 之上，与浅水碳酸盐台地的退积和盆地地层凝结有关。结果表明，在未来的全球相关性中，DICE 应仅限于稍微晚于 Drumian GSSP 日期的负碳同位素异常。
The Global boundary Stratotype Section and Point (GSSP) of the Cambrian Series 3 (formerly the Middle Cambrian) Drumian Stage is defined by the first appearance datum (FAD) of the agnostoid trilobite Ptychagnostus atavus in the deep-water Wheeler Formation of the Drum Mountains in Utah, USA. In the Great Basin (USA), China and Scandinavia the FAD of P. atavus is associated with transgression and with a negative carbon isotope excursion named the Drumian Carbon isotope Excursion (DICE). However, the relationship between the FAD of P. atavus, sea-level changes, and the DICE is tentative, mainly due to the paucity of biostratigraphic data in shallow-water sections that limit correlation between deep- and shallow-water chemostratigraphic sections. An integrated sequence and chemostratigraphic study across a platform-to-basin transect in western Utah and southern Nevada indicates that the DICE is stratigraphically located above the FAD of P. atavus, associated with retrogradation of the shallow-water carbonate platform and with stratigraphic condensation in the basin. The results suggest that in future global correlations, the DICE should be restricted to the negative carbon isotope anomaly slightly post-dating the Drumian GSSP.