High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early–Middle Cambrian (Stage 4–5) extinction
High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early–Middle Cambrian (Stage 4–5) extinction
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DOI：
10.1130/g35434.1
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发表时间：
2014-06
期刊：
影响因子：
5.8
通讯作者：
F. Jourdan;K. Hodges;B. Sell;U. Schaltegger;M. Wingate;L. Evins;U. Söderlund;P. Haines;D. Phill
中科院分区：
文献类型：
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作者：
F. Jourdan;K. Hodges;B. Sell;U. Schaltegger;M. Wingate;L. Evins;U. Söderlund;P. Haines;D. Phill
大量的Kalkarindji洪水玄武岩在寒武纪期间在澳大利亚爆发，覆盖面积超过2 x 10（6）km（2）。新的U-Pb和Ar-40/Ar-39年龄数据的侵入岩和熔岩流产生统计上难以区分的年龄在约。511 Ma，表明该地区的侵位时间相对较短。锆石年龄为510.7 ± 0.6Ma，与早-中寒武世（第4-5期）界线年龄510 ± 1 Ma在几十万年的时间上是不可区分的，这标志着中生代的第一次严重灭绝和延长的海洋缺氧期。硫的浓度测量范围从< 50到1900 μ g/g，以及对大面积爆发性火山角砾岩的分形分析表明，爆炸和蒸汽岩浆爆炸有助于将大量的硫注入平流层。此外，岩浆侵入石油、天然气和硫酸盐矿床可能产生了大量的甲烷和二氧化硫，沿着火山气体，它们结合在一起会导致气候的振荡，并导致寒武纪的灭绝。（减）
The voluminous Kalkarindji flood basalts erupted in Australia during the Cambrian and covered >2 x 10(6) km(2). New U-Pb and Ar-40/Ar-39 age data from intrusive rocks and lava flows yielded statistically indistinguishable ages at ca. 511 Ma, suggesting a relatively brief emplacement for this province. A zircon age of 510.7 +/- 0.6 Ma shows that this province is temporally indistinguishable at the few-hundred-thousand-year level from the Early-Middle Cambrian (Stage 4-5) boundary age of 510 +/- 1 Ma, which marks the first severe extinction of the Phanerozoic and an extended marine anoxia period. Sulfur concentration measurements ranging from < 50 to 1900 mu g/g, and fractal analysis of extensive explosive volcanic breccias, suggest that blasts and phreatomagmatic explosions have contributed to injection of large amounts of sulfur into the stratosphere. In addition, magma intrusions in oil, gas, and sulfate deposits may have generated significant emission of CH4 and SO2 which, along with volcanic gases, would have combined to cause an oscillation of the climate and led to the Cambrian extinction. (Less)