Evolution of the 87Sr/86Sr composition of Neoproterozoic seawater
Evolution of the 87Sr/86Sr composition of Neoproterozoic seawater
复制标题
DOI：
10.1016/j.palaeo.2007.02.028
复制
发表时间：
2007-12-06
影响因子：
3
通讯作者：
Bowring, Samuel A.
中科院分区：
文献类型：
--
作者：
Halverson, Galen P.;Dudas, Francis O.;Bowring, Samuel A.
前寒武纪生物地层学和放射性数据的有限性和低分辨率，需要使用海洋化学地层学来对比和整合破碎的地层记录。我们提出了一个新的复合记录的锶同位素组成的海水在新元古代（1000-542马）的时代，是与高分辨率三角洲C-13（碳酸盐）的汇编。Sr-87/Sr-86记录主要由加拿大西北部、斯瓦尔巴特群岛和纳米比亚北方的富碳酸盐岩序列的新数据和先前发表的数据组成。已发表的数据从其他晚新元古代继承保守地包括填补埃迪卡拉纪（635-542马）。与先前的汇编一致，由此产生的锶同位素记录显示整个新元古代Sr-87/Sr-86系统性上升，从时代开始时的低至0.7055到接近结束时的大于0.7085。尽管这些记录的分辨率和时间校准仍然很差，但似乎Sr-87/Sr-86的下降、拐点和快速变化都对应于重大的地球化学或气候事件。然而，这一记录既不支持三角洲C-13和Sr-87/Sr-86之间的紧密耦合，通过大陆侵蚀，也不支持广泛的造山运动作为增加Sr-87/Sr-86组成的主要驱动力。相反，Sr-87/Sr-86在新元古代的稳步上升对应于超大陆Rodinia的分裂。(C)2007 Elsevier B. V.保留所有权利。
The limited availability and low resolution of biostratigraphic and radiometric data in the Precambrian necessitate using marine chemostratigraphy to correlate and integrate the fragmentary stratigraphic record. We present a new composite record of the strontium isotope composition of seawater during the Neoproterozoic (1000-542 Ma) Era that is linked to a high-resolution delta C-13 (carbonate) compilation. The Sr-87/Sr-86 record consists predominantly of new and previously published data from carbonate-rich successions in northwest Canada, Svalbard, and northern Namibia. Published data from other late Neoproterozoic successions are conservatively included to fill in the Ediacaran Period (635-542 Ma). Consistent with previous compilations, the resulting strontium isotope record shows a systematic rise in Sr-87/Sr-86 throughout the Neoproterozoic, from as low as, 0.7055 at the beginning of the era to greater than 0.7085 towards the end. Though the record remains poorly resolved and time-calibrated, it appears that declines, inflections, and rapid changes in Sr-87/Sr-86 all correspond to major biogeochernical or climatic events. However, this record supports neither a tight coupling between delta C-13 and Sr-87/Sr-86 via continental erosion nor widespread mountain-building as the main driver for increasing Sr-87/Sr-86 compositions during the Neoproterozoic. Rather, the steady rise in Sr-87/Sr-86 during the Neoproterozoic corresponded to the break-up of the supercontinent Rodinia. (C) 2007 Elsevier B.V. All rights reserved.