Petrogenesis and metallogenic implications of Late Cretaceous I- and S-type granites in Dachang-Kunlunguan ore belt, southwestern South China Block
Petrogenesis and metallogenic implications of Late Cretaceous I- and S-type granites in Dachang-Kunlunguan ore belt, southwestern South China Block
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华南地块西南部大厂—昆仑关矿带晚白垩世I型、S型花岗岩岩石成因及成矿意义
DOI：
10.1016/j.oregeorev.2019.103079
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发表时间：
2019
影响因子：
3.3
通讯作者：
Deng Jun
中科院分区：
文献类型：
--
作者：
Wang Tingyi;Li Gongjian;Wang Qingfei;Santosh M;Zhan Qizuan;Deng Jun
华南地块西南部是我国主要的锡、钨、铜成矿区之一。到中生代花岗岩套。岩浆成岩作用与成矿作用的成因关系尚不清楚。Tallogeny没有很好的约束。在此我们评价了晚白垩世花岗岩的岩石成因及其与。省东部大厂-昆仑关矿带的区域成矿作用。这个腰带。包括形成于约98 ~ 97 Ma的黑云母花岗岩，与昆仑关地区铜钨矿床有关；约92 Ma的碱长石花岗岩是大厂锡成矿的主要原因。Kunlunguan。黑云母花岗岩的p2o含量低（0.12 ~ 0.18 wt%）， CIPW标准刚玉含量低（0.28 ~ 1.99 wt%）， ASI含量低。值（1.00 ~ 1.14），符合i型花岗岩的特征。相比之下，大厂碱性长石。花岗岩为强过铝质（ASI = 1.29-1.44）， p2o - 5高（0.25-0.34 wt%）， CIPW规范。刚玉含量（3.75-4.91 wt%），与s型花岗岩相当。昆仑关和昆仑关的锆石颗粒。大厂花岗岩的εHf(t)值分别为- 11.0 ~ - 1.2和- 6.5 ~ - 2.1。根据地球化学和Hf同位素特征，确定昆仑关花岗岩的母岩浆为。推断其主要来源于古元古代至中元古代变质岩和岩浆的混合熔体。变质沉积岩中地幔成分较少，而大厂花岗岩主要形成。通过中元古代变质沉积岩的部分熔融作用。大厂s型花岗岩显示高。DI和FeO的T /MgO值，低Tzr和La/Yb， Zr/Hf和Nb/Ta的比率，以及强烈负的Sr， Ba和Eu。异常，表明它们是高度分异的花岗岩；而昆仑关i型花岗岩则有。目睹了较少的分馏。大厂花岗岩经钾长石、斜长石、黑云母、钾长石分选。Nb/Ta < 5指示岩浆-热液相互作用的独居石和allanite。Kunlunguan。花岗岩具有较高的锆石Ce/Ce*比值（1 ~ 400，平均70），与典型含铜花岗岩相似。表明相对较高的氧逸度，并解释了Cu-的相关形成。W存款。高分选的大厂s型花岗岩氧逸度低（多< 40），相似。与典型含锡花岗岩类相吻合，有利于锡的成矿作用。
The southwestern part of the South China Block is one of the major Sn, W and Cu metallogenic provinces related.to Mesozoic granitoid suites. However, the genetic relationship between the magmatic petrogenesis and me-.tallogeny is not well-constrained. Here we evaluate the petrogenesis of Late Cretaceous granites and their link to.regional metallogeny from the Dachang–Kunlunguan ore belt in the eastern part of the province. This belt.includes biotite granites formed at ca. 98–97 Ma associated with Cu–W deposit in the Kunlunguan area, and the.alkali-feldspar granites emplaced at ca. 92 Ma responsible for Dachang Sn mineralization. The Kunlunguan.biotite granites have low P 2 O 5 (0.12–0.18 wt%), CIPW normative corundum contents (0.28–1.99 wt%) and ASI.values (1.00 to 1.14), consistent with the features of I-type granites. In contrast, the Dachang alkali-feldspar.granites are strongly peraluminous (ASI =1.29–1.44) with high P 2 O 5 (0.25–0.34 wt%) and CIPW normative.corundum contents (3.75–4.91 wt%), comparable to S-type granites. Zircon grains from the Kunlunguan and.Dachang granites show different εHf(t) values ranging from −11.0 to −1.2 and from −6.5 to −2.1, respec-.tively. Based on the geochemical and Hf isotope features, the parent magmas of the Kunlunguan granites are.inferred to have been dominantly derived from mixed melts of Paleo- to Mesoproterozoic metaigneous and.metasedimentary sources with minor mantle components, whereas Dachang granites were mainly formed.through partial melting of Mesoproterozoic metasedimentary rocks. The Dachang S-type granites display high.values of DI and FeO T /MgO, low Tzr and ratios of La/Yb, Zr/Hf and Nb/Ta and strongly negative Sr, Ba and Eu.anomalies, suggesting that they are highly fractionated granites; whereas the Kunlunguan I-type granites have.witnessed less fractionation. The Dachang granites underwent fractionation of K-feldspar, plagioclase, biotite,.monazite and allanite with magmatic-hydrothermal interaction indicated by Nb/Ta < 5. The Kunlunguan.granites have high zircon Ce/Ce* ratios (1–400, average 70), which resemble those of typical Cu ore-bearing.granitoids in Myanmar, indicating relatively high oxygen fugacity and explaining the associated formation of Cu-.W deposit. The highly fractionated Dachang S-type granites show low oxygen fugacity (mostly < 40), similar.with that of the typical Sn ore-bearing granitoids, which favored the Sn mineralization.