Episodic, mafic crust formation from 4.5 to 2.8 Ga: New evidence from detrital zircons, Slave craton, Canada
Episodic, mafic crust formation from 4.5 to 2.8 Ga: New evidence from detrital zircons, Slave craton, Canada
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DOI：
10.1130/g24861a.1
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发表时间：
2008-11
期刊：
影响因子：
5.8
通讯作者：
A. Pietranik;C. Hawkesworth;C. Storey;A. Kemp;K. Sircombe;M. Whitehouse;W. Bleeker
中科院分区：
文献类型：
--
作者：
A. Pietranik;C. Hawkesworth;C. Storey;A. Kemp;K. Sircombe;M. Whitehouse;W. Bleeker
加拿大Slave克拉通碎屑锆石的δ ~（18）O和Hf值表明，该克拉通在1980 ~ 1990年间经历了3期地壳形成。4.5和2.8Ga，即在约.约4.4-4.5 Ga。3.8 Ga和Ca。3.4佐治亚州大多数的青年地壳似乎已镁铁质的组成，并没有明确的证据表明，初始花岗岩原地壳在冥古宙的奴隶克拉通。锆石的初始Hf值范围从3.9 Ga增加到2.8 Ga，表明地幔中新物质的提取和老地壳的改造对大陆地壳的长期演化具有重要意义。对锆石中Hf数据的初步分析表明，地壳生成的三个阶段可能具有全球重要性。形成于太古代和冥古宙的镁铁质地壳随后被改造了至少约0.5-1.5亿年，非洲的奴隶克拉通、冈瓦纳和林波波带的数据表明，
The ϵHf and δ18O values in detrital zircons from the Slave craton, Canada, indicate three episodes of crust formation between ca. 4.5 and 2.8 Ga, namely at ca. 4.4–4.5 Ga, ca. 3.8 Ga, and ca. 3.4 Ga. Most of the juvenile crust appears to have been mafic in composition, and there is no clear evidence for initial granitic protocrust in the Hadean of the Slave craton. The range of initial ϵHf values in zircons increases from 3.9 to 2.8 Ga, indicating that both extraction of new material from mantle and reworking of the older crust are important for the secular evolution of the continental crust. A preliminary review of available Hf data in zircons suggests that the three episodes of crust generation may have been of global importance. The mafic crust formed in the Archean and the Hadean was then reworked for at least ~0.5–1.5 b.y., as indicated by data from the Slave craton, Gondwana, and the Limpopo Belt of Africa.