Early Neoarchean Magmatic and Paleoproterozoic Metamorphic Events in the Northern North China Craton: SHRIMP Zircon Dating and Hf Isotopes of Archean Rocks from the Miyun Area, Beijing
Early Neoarchean Magmatic and Paleoproterozoic Metamorphic Events in the Northern North China Craton: SHRIMP Zircon Dating and Hf Isotopes of Archean Rocks from the Miyun Area, Beijing
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DOI：
10.1111/1755-6724.13320
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
Yuruo Shi;Xitao Zhao
中科院分区：
文献类型：
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作者：
Yuruo Shi;Xitao Zhao
北京密云地区位于华北造山带北方，包括多种太古宙花岗岩类和变质岩。英云闪长岩中锆石的岩浆域揭示了新太古代早期（2752±7 Ma）的年龄，其δ Hf（t）在3.1 ~ 7.4之间，tDM 1（Hf）在2742 ~ 2823 Ma之间，与它们的U-Pb年龄相似，表明它们仅在结晶之前的短时间内来自亏损地幔源。密云地区花岗岩、片麻岩、斜长角闪岩和角闪岩的SHRIMP锆石定年结果表明，它们的局限侵位年龄为2594 ~ 2496 Ma。它们也记录了大约1000年的变质事件。2.50 Ga、2.44 Ga和1.82 Ga，与华北克拉通广泛分布的晚新太古代岩石具有相似的演化历史。这些晚新太古代侵入岩的岩浆锆石区域的正Hf（t）值为1.5 ~ 5.9，模式年龄小于3.0 Ga，表明它们主要来自于幼年地壳源区，并表明新太古代期间北方NCC发生了显著的地壳生长。华北克拉通广泛发育晚古元古代变质作用，不仅在华北造山带，而且在东西陆块地区也有，表明晚古元古代是不同微大陆的组合，最终固结形成华北克拉通，并与古中元古代哥伦比亚或努纳超大陆的发育有关。
The Miyun area of Beijing is located in the northern part of the North China Craton (NCC) and includes a variety of Archean granitoids and metamorphic rocks. Magmatic domains in zircon from a tonalite reveal Early Neoarchean (2752±7 Ma) ages show a small range in ∊Hf(t) from 3.1 to 7.4 and tDM1(Hf) from 2742 to 2823 Ma, similar to their U‐Pb ages, indicating derivation from a depleted mantle source only a short time prior to crystallization. SHRIMP zircon ages of granite, gneiss, amphibolite and hornblendite in the Miyun area reveal restricted emplacement ages from 2594 to 2496 Ma. They also record metamorphic events at ca. 2.50 Ga, 2.44 Ga and 1.82 Ga, showing a similar evolutionary history to the widely distributed Late Neoarchean rocks in the NCC. Positive ∊Hf(t) values of 1.5 to 5.9, with model ages younger than 3.0 Ga for magmatic zircon domains from these Late Neoarchean intrusive rocks indicate that they are predominantly derived from juvenile crustal sources and suggest that significant crustal growth occurred in the northern NCC during the Neoarchean. Late Paleoproterozoic metamorphism developed widely in the NCC, not only in the Trans‐North China Orogen, but also in areas of Eastern and Western Blocks, which suggest that the late Paleoproterozoic was the assembly of different micro‐continents, which resulted in the final consolidation to form the NCC, and related to the development of the Paleo‐Mesoproterozoic Columbia or Nuna supercontinent.