Geochronology, geochemistry and Hf isotopic composition of Late Cretaceous Laojunshan granites in the western Cathaysia block of South China and their metallogenic and tectonic implications
Geochronology, geochemistry and Hf isotopic composition of Late Cretaceous Laojunshan granites in the western Cathaysia block of South China and their metallogenic and tectonic implications
复制标题
华南华夏地块西部晚白垩世老君山花岗岩年代学、地球化学、Hf同位素组成及其成矿构造意义
DOI：
10.1016/j.oregeorev.2019.103297
复制
发表时间：
2020-02
影响因子：
3.3
通讯作者：
王彩艳
中科院分区：
文献类型：
--
作者：
任涛;杨光树;温汉捷;许赛华;王彩艳
在西华夏地块老君山地区发现了富Sn、In和W的花岗岩，包括粗粒二云母二长花岗岩（CMG）和细粒二云母二长花岗岩（FMG）。激光烧蚀-电感耦合等离子体质谱法（LA-ICP-MS）测得CMG和FMG的锆石U-Pb年龄分别为85.6 ± 0.8 ~ 90.37 ± 0.7 Ma和89.9 ± 1.4 Ma。所有样品的总碱含量（5.74wt%~ 9.73wt%）和铝饱和指数（0.95 ~ 1.79）均较高，表明花岗岩多为强过铝花岗岩。花岗岩富集P、Rb、Cs、Sn、Li、Be和U，亏损Ti、Mg、Co、Ni、Sr、Ba、Zr和Hf。斜长石和钾长石的分离结晶是岩浆分异的主要过程，并控制了Rb、Sr、Ba和Eu的浓度。副矿物磷灰石、独居石、钛铁矿等对稀土元素的分馏作用明显。这些地球化学特征表明，大部分岩石是高度分馏的S型花岗岩。CMG和FMG锆石样品的εHf（t）值为-12.88 ~-1.19，两阶段Hf模式年龄为1.2 ~ 1.9 Ga。地球化学和同位素资料表明，老君山花岗岩形成于中-古元古代陆壳变质泥质岩结晶基底之上。老君山地区晚白垩世岩石圈强烈伸展导致软流圈上涌，使变质泥质岩发生部分熔融，形成广泛分布的S型花岗岩。滇东南岩石圈伸展和白垩纪岩浆活动可能与古特提斯洋壳拆沉作用有关，后者俯冲到印支陆块之下。
Sn-, In- and W-rich granites are identified in Laojunshan area in the western Cathaysia block, South China, including coarse-grained two-mica monzogranite (CMG) and fine-grained two-mica monzogranite (FMG). Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb dating of CMG and FMG are from 85.6 ± 0.8 Ma to 90.37 ± 0.7 Ma and 89.9 ± 1.4 Ma, respectively. All samples have relatively high total alkalis contents (5.74 wt% to 9.73 wt%) and Al saturation indices (0.95 to 1.79), indicating that most of granites belong to the strongly peraluminous granites. The granites are enriched in P, Rb, Cs, Sn, Li, Be, and U, and are depleted in Ti, Mg, Co, Ni, Sr, Ba, Zr, and Hf. The fractional crystallization of plagioclase and K-feldspar was the principal process of magmatic differentiation that controlled Rb, Sr, Ba and Eu concentrations. While rare earth elements were fractionated by accessory minerals such as apatite, monazite or ilmenite. These geochemical features suggest that most of rocks are highly fractionated S-type granites. The εHf(t) values of the zircon samples from CMG and FMG range from −12.88 to −1.19, with the two-stage Hf model ages ranging from 1.2 Ga to 1.9 Ga. The geochemical and isotopic data show that the Laojunshan granites are derived from a crystalline basement that has metamorphosed pelitic rocks from the Mes-paleoproterozoic continental crust. The upwelling of the asthenosphere caused by a strong lithospheric extension led to the partial melting of the metamorphosed pelitic rocks to form widespread Late Cretaceous S-type granites in the Laojunshan area. Lithospheric extension and Cretaceous magma in SE Yunnan are probably related to the Palaeo-tethys ocean crustal delamination, which subducted beneath the Indochina block.
登录
查看更多内容
影响因子：
2.1
作者：
A. Müller;R. Thomas;M. Wiedenbeck;R. Seltmann;K. Breiter
通讯作者：
A. Müller;R. Thomas;M. Wiedenbeck;R. Seltmann;K. Breiter
影响因子：
1.8
作者：
Y. Liu;Zheng‐Xiang Li;H. Li;L. Guo;W. Xu;L. Ye;C. Li;D. Pi
通讯作者：
Y. Liu;Zheng‐Xiang Li;H. Li;L. Guo;W. Xu;L. Ye;C. Li;D. Pi
滇东南南洋田钨矿床矿脉黑云母40Ar-39Ar定年及斑岩花岗岩脉锆石U-Pb定年
影响因子：
3.3
作者：
任涛;王彩艳;韩润生;黄建国;徐赛华
通讯作者：
徐赛华
影响因子：
3.5
作者：
R. Thomas;H. Förster;K. Rickers;J. Webster
通讯作者：
R. Thomas;H. Förster;K. Rickers;J. Webster
影响因子：
2.3
作者：
Kai‐Jun Zhang;Jianxin Cai;Junbin Zhu
通讯作者：
Kai‐Jun Zhang;Jianxin Cai;Junbin Zhu