Reevaluating the evidence for a Hadean-Eoarchean dynamo
Reevaluating the evidence for a Hadean-Eoarchean dynamo
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DOI：
10.1126/sciadv.aav9634
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发表时间：
2020-04-01
期刊：
影响因子：
13.6
通讯作者：
Maloof, Adam C.
中科院分区：
文献类型：
--
作者：
Borlina, Caue S.;Weiss, Benjamin P.;Maloof, Adam C.
地球发电机的起源时间对行星内部的热演化和早期地球的可居住性具有重要意义。有人提出，来自西澳大利亚州杰克山的碎屑锆石颗粒为早在42亿年前（Ga）的活跃地球发电机提供了证据。然而，我们对杰克山锆石的古地磁、地球化学和矿物学研究表明，大多数锆石的磁记录性能较差，二次磁化载流子的形成时间比锆石晚。因此，3.5 Ga前的地球发电机是否存在仍然未知。
The time of origin of the geodynamo has important implications for the thermal evolution of the planetary interior and the habitability of early Earth. It has been proposed that detrital zircon grains from Jack Hills, Western Australia, provide evidence for an active geodynamo as early as 4.2 billion years (Ga) ago. However, our combined paleomagnetic, geochemical, and mineralogical studies on Jack Hills zircons indicate that most have poor magnetic recording properties and secondary magnetization carriers that postdate the formation of the zircons. Therefore, the existence of the geodynamo before 3.5 Ga ago remains unknown.