Rates of generation and growth of the continental crust
Rates of generation and growth of the continental crust
复制标题
DOI：
10.1016/j.gsf.2018.02.004
复制
发表时间：
2019-01-01
影响因子：
8.9
通讯作者：
Dhuime, Bruno
中科院分区：
文献类型：
--
作者：
Hawkesworth, Chris;Cawood, Peter A.;Dhuime, Bruno
关于大陆地壳何时以及如何形成的模型受到地壳增长率估计的限制。保存在大陆地壳中的事件记录在时间上是不均匀的，具有独特的火成岩结晶、变质、大陆边缘和矿化的年龄峰和谷。在大多数情况下，这些都是全球性的签名，年龄的高峰往往与增加改造的预先存在的地壳，反映在Hf同位素比的锆石和他们的氧同位素比升高的时期。地壳改造的增加归因于与挤压构造和超大陆发展有关的地壳增厚时期。岩浆类型类似于那些从最近的板内和俯冲相关的设置似乎已经产生在不同的地区在大致相似的时间之前，类似于3.0 Ga。很难将这种详细的个案研究结果放在更全球的背景下，但一种办法是考虑板块构造何时成为新生大陆地壳生成的主要机制。讨论了陆壳生长模型的发展，基于不同数据集的一些模型表明，现今陆壳体积的65%~ 70%是由3Ga形成的。这种估计值可能是最低值，但由于与3Ga相似，大陆地壳的增长速度有所下降。这种减少与大陆地壳再循环回地幔的速度加快有关，而与大陆地壳生成速度的减少无关。板块构造导致新地壳的产生和新地壳沿沿着破坏性板块边缘的破坏。因此，大陆地壳生长速率在类似于3Ga时的降低被用来反映板块构造成为新大陆地壳生成的主导机制的时期。(C)2018年，中国地质大学（北京）和北京大学。制作和主办：Elsevier B. V.
Models for when and how the continental crust was formed are constrained by estimates in the rates of crustal growth. The record of events preserved in the continental crust is heterogeneous in time with distinctive peaks and troughs of ages for igneous crystallisation, metamorphism, continental margins and mineralisation. For the most part these are global signatures, and the peaks of ages tend to be associated with periods of increased reworking of pre-existing crust, reflected in the Hf isotope ratios of zircons and their elevated oxygen isotope ratios. Increased crustal reworking is attributed to periods of crustal thickening associated with compressional tectonics and the development of supercontinents. Magma types similar to those from recent within-plate and subduction related settings appear to have been generated in different areas at broadly similar times before similar to 3.0 Ga. It can be difficult to put the results of such detailed case studies into a more global context, but one approach is to consider when plate tectonics became the dominant mechanism involved in the generation of juvenile continental crust. The development of crustal growth models for the continental crust are discussed, and a number of models based on different data sets indicate that 65%-70% of the present volume of the continental crust was generated by 3 Ga. Such estimates may represent minimum values, but since similar to 3 Ga there has been a reduction in the rates of growth of the continental crust. This reduction is linked to an increase in the rates at which continental crust is recycled back into the mantle, and not to a reduction in the rates at which continental crust was generated. Plate tectonics results in both the generation of new crust and its destruction along destructive plate margins. Thus, the reduction in the rate of continental crustal growth at similar to 3 Ga is taken to reflect the period in which plate tectonics became the dominant mechanism by which new continental crust was generated. (C) 2018, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.