Oblique continental collision and the formation of syn-collisional A-type granites: insights from the Early Jurassic Baoji granite suite in the Qinling orogenic belt, central China
文献类型：期刊论文
| 作者 | Ren, Long; Liang, Huaying; Bao, Zhiwei; Huang, Wenting |
| 刊名 | INTERNATIONAL GEOLOGY REVIEW
 |
| 出版日期 | 2023 |
| 卷号 | 65期号:7页码:1034-1055 |
| ISSN号 | 0020-6814 |
| DOI | 10.1080/00206814.2020.1868356 |
| 英文摘要 | A-type granites are conventionally interpreted to be formed in late post-collisional or anorogenic settings. However, we firstly identified an Early Jurassic syn-collisional A-type granite suite in the Qinling orogenic belt: the Baoji granite suite. A comprehensive investigation into its mineralogical, petrological, geochronological, and geochemical characteristics can shed light on the genesis of syn-collisional A-type granites and geodynamic evolution of collisional orogeny. The Baoji granite suite contains two types of rocks: (1) A-type granites including biotite syenite, coarse-grained, porphyritic, and fine-grained syenogranites, and alkali-feldspar granite, and (2) magnesian monzodiorite; both types are coeval, with zircon U-Pb ages of ca. 190 Ma. The A-type granites yield A(1)-type trace element signatures and large variations in trace element contents, with Ba contents of 16.9-762 ppm, Sr of 11.0-211 ppm, Rb of 193-645 ppm, and Eu of 0.08-1.24 ppm. Their radiogenic isotope compositions (Sr-87/Sr-86(i) = 0.70631-0.70637; epsilon Nd = -5.18 to -3.84; epsilon Hf = -5.01 to +2.76) are similar, and overlap those of Neoproterozoic OIB-like basic volcanics from the South Qinling belt. These characteristics show that the A-type granites originated from the anatexis of OIB-like lower crust and underwent fractional crystallization in a silicic magma reservoir. The monzodiorite has low SiO2 contents (49.82-53.29 wt.%) and enriched radiogenic isotopic compositions (Sr-87/Sr-86(i) = 0.70554-0.70638; epsilon Nd = -11.0 to -5.28) contains abundant hornblende and biotite (similar to 40%), and exhibits evidence of magma mingling. It also contains two groups of zircon: pristine and unzoned zircon that yields negative Hf isotope compositions (epsilon Hf = -9.42 to -3.14), and xenocrystic zircon that yields similar Hf isotope compositions (epsilon Hf = -3.54 to +1.85) to the A-type granites. These characteristics demonstrate that the monzodiorite was derived from the differentiation of basaltic partial melts of an enriched mantle source, and mingled with the A-type granitic magma during its ascent and emplacement into a silicic magma reservoir. Along with regional records of the Early Jurassic magmatism, deformation, metamorphism, and sedimentation, the genetic models for the Baoji A-type granites and monzodiorite suggest that the Middle Triassic to Early Jurassic oblique continental collision (ca. 230-190 Ma) produced coupled EW-trending strike-slip and NE-trending extensional faults at crustal levels and Rayleigh-Taylor (gravitational) convective instabilities at mantle depths in the Qinling orogenic belt, which controlled the production of the syn-collisional A-type granite suite. Our work also indicates that the A-type granites can be formed in syn-collisional setting in response to oblique continental collision and the resultant slow foundering of a high-density lithospheric root; therefore, we suggest that the syn-collisional A-type granites are evidence for oblique continental collision. |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000605708100001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/80383]  |
| 专题 | 中国科学院矿物学与成矿学重点实验室 |
| 推荐引用方式 GB/T 7714 | Ren, Long,Liang, Huaying,Bao, Zhiwei,et al. Oblique continental collision and the formation of syn-collisional A-type granites: insights from the Early Jurassic Baoji granite suite in the Qinling orogenic belt, central China[J]. INTERNATIONAL GEOLOGY REVIEW,2023,65(7):1034-1055. |
| APA | Ren, Long,Liang, Huaying,Bao, Zhiwei,&Huang, Wenting.(2023).Oblique continental collision and the formation of syn-collisional A-type granites: insights from the Early Jurassic Baoji granite suite in the Qinling orogenic belt, central China.INTERNATIONAL GEOLOGY REVIEW,65(7),1034-1055. |
| MLA | Ren, Long,et al."Oblique continental collision and the formation of syn-collisional A-type granites: insights from the Early Jurassic Baoji granite suite in the Qinling orogenic belt, central China".INTERNATIONAL GEOLOGY REVIEW 65.7(2023):1034-1055. |
入库方式： OAI收割
来源：广州地球化学研究所
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