التفاصيل البيبلوغرافية
| العنوان: |
Two episodes of late Mesoproterozoic magmatism in the southwestern Yangtze Block, China, and their association with Grenville-aged orogenic cycles. |
| المؤلفون: |
Yan-Jun Wang1,2 zhuweiguang@vip.gyig.ac.cn, Wei-Guang Zhu2, Zheng-Xiang Li3, Hong Zhong2,4, Zhong-Jie Bai2, Cheng-Biao Leng1, Jian-Bing Xu1 |
| المصدر: |
Geological Society of America Bulletin. Mar/Apr2024, Vol. 136 Issue 3/4, p1023-1036. 14p. |
| مصطلحات موضوعية: |
*SECONDARY ion mass spectrometry, *DIKES (Geology), *ZIRCON analysis, *MAGMATISM |
| مصطلحات جغرافية: |
HAINAN Sheng (China) |
| مستخلص: |
We report three sets of newly identified late Mesoproterozoic mafic intrusions in the southwestern Yangtze Block, China. Secondary ion mass spectrometry (SIMS) baddeleyite and zircon U-Pb analyses yield crystallization ages of ca. 1.15 Ga for the Boka dolerites, ca. 1.07 Ga for the Lanniping gabbros, and ca. 1.06 Ga for the Tong'an mafic dikes. These are tholeiitic to alkaline rocks with enriched mid-ocean-ridge basalt (E-MORB)-like trace-element patterns and superchondritic εNd(t) values, indicating a partial melting origin from the asthenospheric mantle. These results, along with existing data, define two episodes of late Mesoproterozoic, rift-related mafic magmatism in the southwestern Yangtze Block: an early phase at 1.17-1.14 Ga and a late phase at 1.07-1.02 Ga. Initiation of the two episodes of extensional events in the southwestern Yangtze Block coincided with high-grade Grenville-aged metamorphism in Hainan Island and possible early collision of Cathaysia with the southwestern Yangtze Block, indicating an impactogen model. Therefore, we interpret the observed two episodes to have resulted from local collision between the southwestern Yangtze Block and the Cathaysia Block (including Hainan Island), which was possibly a part of western Laurentia during the assembly of Rodinia. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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