Diversity of burial rates in convergent settings decreased as Earth aged.
Diversity of burial rates in convergent settings decreased as Earth aged.
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DOI：
10.1038/srep26359
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发表时间：
2016-05-24
影响因子：
4.6
通讯作者：
Stevens G
中科院分区：
文献类型：
--
作者：
Nicoli G;Moyen JF;Stevens G
大陆地壳的演化和生长与地球地球动力学过程的演化有着千丝万缕的联系。大陆地壳内的碎屑锆石记录以及该地壳的同位素组成表明，新生的长英质物质的数量随着时间的推移而减少，并且在地质近代，新地壳的生成通过地壳再循环回到俯冲带内的地幔中来平衡。然而事情不可能总是如此。然而，前寒武纪地球的地壳性质和地壳改造过程并没有得到很好的限制。在这里，我们使用碎屑锆石年龄和变质沉积单元的变质压力-温度-时间（P-T-t）信息，这些变质沉积单元沉积在太古宙、元古代和显生宙地形的汇聚环境中，来表征埋藏率最小估计值（km.Ma−1）随岩石年龄的变化。已证实的埋藏率下降与太古代和元古代新生长英质地壳产量的逐渐减少呈正相关。太古宙的埋葬率也比现代更加多样化。我们对这些特征的解释是反映了从太古代到现在构造过程多样性的逐渐减少，以及独特的显生宙现代式碰撞的出现。
The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth’s geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma−1) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision.