South Australian U-Pb zircon (CA-ID-TIMS) age supports globally synchronous Sturtian deglaciation
South Australian U-Pb zircon (CA-ID-TIMS) age supports globally synchronous Sturtian deglaciation
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DOI：
10.1016/j.precamres.2018.07.007
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发表时间：
2018-09-01
影响因子：
3.8
通讯作者：
Nordsvan, Adam
中科院分区：
文献类型：
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作者：
Cox, Grant M.;Isakson, Vincent;Nordsvan, Adam
雪球地球假说的一个核心预测是，在低纬度地区，冰川的开始应该是同步的，而在全球范围内，冰川的结束应该是快速和同步的。高精度U/Pb锆石年龄为斯图特冰期（约716 Ma）在多个大陆同步开始（误差范围内）提供了支持证据。Re-Os技术在富有机质页岩和碳酸盐岩上的成功应用，使得全球同步的斯图特脱冰（约660 Ma）成为可能，但稀疏的同位素年龄限制使这一观点尚存争议。本文报道了南澳Wilyerpa组末Sturtian组首次高精度U-Pb锆石年龄为663.03 +/- 0.11 Ma （2 sigma）。这个年龄支持以前公布的年龄，并且允许全球同步的冰川消融。结合冰期开始的时间，这个年龄加强了大约58万yr的斯图亚特雪球持续时间。
A central prediction of the Snowball Earth hypothesis is that glacial onset should be synchronous at low latitudes, and its termination should be rapid and synchronous globally. High precision U/Pb zircon ages provide supporting evidence for the synchronous onset (within error) of the Sturtian glaciation (ca. 716 Ma) on multiple continents. Successful application of Re-Os techniques on organic rich shales and carbonates allow for the possibility of a globally synchronous Sturtian deglaciation (ca. 660 Ma), but the sparse isotopic age constraints leave this open to debate. Here we report the first high precision U-Pb zircon age of 663.03 +/- 0.11 Ma (2 sigma) for the end Sturtian recorded in the Wilyerpa Formation of South Australia. This age supports previously published ages and is permissive with a globally synchronous deglaciation. In conjunction with the timing of glacial onset, this age reinforces the ca. 58 Myr duration of the Sturtian Snowball.