Paleomagnetic evidence for modern-like plate motion velocities at 3.2 Ga
Paleomagnetic evidence for modern-like plate motion velocities at 3.2 Ga
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DOI：
10.1126/sciadv.aaz8670
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发表时间：
2020-04-01
期刊：
影响因子：
13.6
通讯作者：
Rose, Ian R.
中科院分区：
文献类型：
--
作者：
Brenner, Alec R.;Fu, Roger R.;Rose, Ian R.
在太古代[40 ~ 25亿年前]，构造过程和岩石圈生长的模式和速率是相当有争议的主题。古地磁学可以通过量化过去板块的速度来帮助讨论。我们报告了一个古磁极类似的3180万年（马）老Honeyeater玄武岩的东皮尔巴拉，西澳大利亚州，支持一个积极的褶皱测试和微磁成像。44度+/- 15度Honeyeater玄武岩古纬度与先前报道的古纬度的比较要求东皮尔巴拉的平均纬度漂移速率>= 2.5厘米/年，在类似于3180 Ma前的170 Ma期间，与现代板块的速度相当。这一结果是迄今发现的岩石圈长距离运动的最早明确证据。假设这种运动主要是由于板块运动，而不是真正的极地漂移，结果是一致的均变或幕式构造过程的地方由3.2 Ga前。
The mode and rates of tectonic processes and lithospheric growth during the Archean [4.0 to 2.5 billion years (Ga) ago] are subjects of considerable debate. Paleomagnetism may contribute to the discussion by quantifying past plate velocities. We report a paleomagnetic pole for the similar to 3180 million year (Ma) old Honeyeater Basalt of the East Pilbara Craton, Western Australia, supported by a positive fold test and micromagnetic imaging. Comparison of the 44 degrees +/- 15 degrees Honeyeater Basalt paleolatitude with previously reported paleolatitudes requires that the average latitudinal drift rate of the East Pilbara was >= 2.5 cm/year during the similar to 170 Ma preceding 3180 Ma ago, a velocity comparable with those of modern plates. This result is the earliest unambiguous evidence yet uncovered for long-range lithospheric motion. Assuming this motion is due primarily to plate motion instead of true polar wander, the result is consistent with uniformitarian or episodic tectonic processes in place by 3.2 Ga ago.