A Change in the Geodynamics of Continental Growth 3 Billion Years Ago
A Change in the Geodynamics of Continental Growth 3 Billion Years Ago
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DOI：
10.1126/science.1216066
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发表时间：
2012-03-16
期刊：
影响因子：
56.9
通讯作者：
Storey, Craig D.
中科院分区：
文献类型：
--
作者：
Dhuime, Bruno;Hawkesworth, Chris J.;Storey, Craig D.
大陆地壳生长的模型依赖于了解整个地球历史中新地壳的生成和旧地壳的改造之间的平衡。锆石的氧同位素组成是地壳改造的重要档案，其中铀铅和铪同位素数据提供了年龄约束。我们在不同年龄的锆石中发现了铪和氧同位素的系统变化，揭示了改造地壳和新地壳随时间的相对比例。大陆地壳的增长似乎是一个连续的过程，尽管速度是可变的。与30亿年前相似的地壳生长速度的显著下降可能与俯冲驱动的板块构造的开始有关。
Models for the growth of continental crust rely on knowing the balance between the generation of new crust and the reworking of old crust throughout Earth's history. The oxygen isotopic composition of zircons, for which uranium-lead and hafnium isotopic data provide age constraints, is a key archive of crustal reworking. We identified systematic variations in hafnium and oxygen isotopes in zircons of different ages that reveal the relative proportions of reworked crust and of new crust through time. Growth of continental crust appears to have been a continuous process, albeit at variable rates. A marked decrease in the rate of crustal growth at similar to 3 billion years ago may be linked to the onset of subduction-driven plate tectonics.