Estimation of Secular Change in the Size of Continents for Understanding Early Crustal Development
Estimation of Secular Change in the Size of Continents for Understanding Early Crustal Development
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DOI：
10.3389/feart.2020.541094
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发表时间：
2020-12
期刊：
影响因子：
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通讯作者：
H. Sawada
中科院分区：
文献类型：
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作者：
H. Sawada
大陆的大小是了解大陆地壳生长和固体地球演化的重要参数，因为它受到构造运动和地幔对流的影响并影响地壳的保存。本文回顾了早期地球大陆大小的长期变化，重点关注陆源碎屑岩，特别是相对较大大陆上出现的石英砂岩。冥太宙或早太古代最早的大陆地壳宽度约为200-500公里，类似于地幔柱加热沿俯冲带形成的现代大洋岛弧或热点区域的大洋岛屿。通过这种原始大陆地壳的碰撞和融合，大约在大约1000年演化并出现了宽度和长度超过500公里的大陆块。 3.5 Ga。通过进一步合并，大约在 3.5 Ga 期间。 3.3~2.5 Ga出现太古代大陆，其宽度和长度均大于1000公里，仍小于现代大陆。宽度和长度接近 10,000 公里的大陆自大约公元 10 世纪以来就已存在。 2.4 Ga（早元古代）。进一步分析碎屑岩的成分和形成机制将有助于揭示大陆尺寸的更多定量长期变化。
The size of continents is an essential parameter to understand the growth of the continental crust and the evolution of the solid Earth because it is subject to tectonism and mantle convection and affects the preservation of the crust. This article reviews the secular change in the size of continents on the early Earth, focusing on terrigenous clastic rocks, especially quartzose sandstones occurring on relatively large continents. The earliest continental crust in the Hadean or early Archean was produced with a width of ∼200–500 km, similar to modern oceanic island arcs along subduction zones or oceanic islands in hot spot regions by mantle plume heating. Through the collision and amalgamation of such primitive continental crusts, continental blocks over 500 km in width and length evolved and appeared by ca. 3.5 Ga. Through further amalgamation, during ca. 3.3–2.5 Ga, the Archean continents emerged with widths and lengths greater than 1,000 km, which were still smaller than those of modern continents. Continents with widths and lengths of nearly 10,000 km have existed since ca. 2.4 Ga (early Proterozoic). Further analyses of the composition and formation mechanism of clastic rocks will help reveal more quantitative secular changes in the sizes of continents.