Rapid oxygenation of Earth's atmosphere 2.33 billion years ago.
Rapid oxygenation of Earth's atmosphere 2.33 billion years ago.
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DOI：
10.1126/sciadv.1600134
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发表时间：
2016-05
期刊：
影响因子：
13.6
通讯作者：
Summons RE
中科院分区：
文献类型：
--
作者：
Luo G;Ono S;Beukes NJ;Wang DT;Xie S;Summons RE
来自南非岩石的连续多个硫同位素剖面在地质记录中指出了大氧化事件。分子氧（O2）是生物进化的主要驱动力，并塑造了地球地球化学循环的当代景观。虽然在太古代大气中已经记录了氧气的“气息”，但直到古元古代早期，在被称为大氧化事件（GOE）的过程中，大量的O2才不可逆转地积累起来。到目前为止，GOE的时间和这种氧合发生的速率一直受到很大的限制。我们报告的过渡（即，从质量独立成为质量依赖）在多个硫同位素信号的成岩黄铁矿在一个连续的沉积序列中的三个同时代的钻芯在德兰士瓦超群，南非。这些数据精确地将GOE限制在23.3亿年前。新的数据表明，氧化作用发生得很快--在100万年到1000万年之间--随之而来的是海洋硫酸盐存量的缓慢上升。我们的数据表明，气候扰动早于GOE，而GOE之间的关系，“雪球地球”冰川，地球化学循环将需要进一步的地层对比支持精确的年表和古纬度重建。
Continuous multiple sulfur isotope profiles from South African rocks pinpoint the Great Oxygenation Event in the geologic record. Molecular oxygen (O2) is, and has been, a primary driver of biological evolution and shapes the contemporary landscape of Earth’s biogeochemical cycles. Although “whiffs” of oxygen have been documented in the Archean atmosphere, substantial O2 did not accumulate irreversibly until the Early Paleoproterozoic, during what has been termed the Great Oxygenation Event (GOE). The timing of the GOE and the rate at which this oxygenation took place have been poorly constrained until now. We report the transition (that is, from being mass-independent to becoming mass-dependent) in multiple sulfur isotope signals of diagenetic pyrite in a continuous sedimentary sequence in three coeval drill cores in the Transvaal Supergroup, South Africa. These data precisely constrain the GOE to 2.33 billion years ago. The new data suggest that the oxygenation occurred rapidly—within 1 to 10 million years—and was followed by a slower rise in the ocean sulfate inventory. Our data indicate that a climate perturbation predated the GOE, whereas the relationships among GOE, “Snowball Earth” glaciation, and biogeochemical cycling will require further stratigraphic correlation supported with precise chronologies and paleolatitude reconstructions.