气候变化领域集成服务门户(CCPortal): Poikilitic texture of plagioclase in the Quxu batholith of the Gangdese belt, southern Tibet: Implications for magma recharge process

CCPortal

DOI	10.18654/1000.0569/2023.12.08
	Poikilitic texture of plagioclase in the Quxu batholith of the Gangdese belt, southern Tibet: Implications for magma recharge process
	Li Wang; Ma XuXuan; Qiu Liang; Si JiaLiang; Liu DongLiang
发表日期	2023
ISSN	1000-0569
EISSN	2095-8927
起始页码	3641
结束页码	3660
卷号	39 期号:12
英文摘要	The Gangdese belt in southern Tibet is an excellent location for studying the growth and evolution of continental crust as it has undergone the Mesozoic subduction-accretionary orogeny and the Cenozoic collisional orogeny. The Early Eocene Quxu batholith, located at central part of the Gangdese belt, consists of granite, granodiorite, diorite, and gabbro, etc. Lots of chronologic and geochemical studies have been done for the Quxu batholith. However, there are still debates about whether the formation of the Quxu batholith is controlled by magma recharge. Besides, the detailed processes of magma recharge are unclear. The wide distribution of magmatic microgranular enclaves in the granodiorite such as enclave dikes and dispersed enclaves, indicates the important role of magma recharge during the formation of the Quxu batholith. Poikilitic texture, with amphibole embedded in plagioclase, is developed in enclaves. Here, we will focus on the poikilitic texture of plagioclase and the chadacrysts ( e. g., amphibole) and attempt to track the processes of magma recharge through backscattered-electron imaging, mineral energy spectrum scanning, and mineral electron probe analysis. Analytical results reveal that the crystallization temperature and pressure of the amphibole chadacrysts are the highest (783 similar to 853 degrees C, 0.23 similar to 0. 45GPa), followed by the amphiboles in the groundmass of enclaves (781 similar to 808 degrees C, 0.21 0. 31GPa), and then the amphiboles in the granodioritic host rocks (769 similar to 802 degrees C, 0. 18 similar to 0. 26GPa). In addition, plagioclase with poikilitic texture develops obvious discontinuous zoning, and the sodic core indicates the existence of crystal mush. Based on these observations, we establish a tentative model to explain the process of magma recharge and the formation of poikilitic texture. Mafic magma rises along the fractures in the lower part of felsic crystal mush and quenches, leading to the formation of numerous small grains of amphibole. Subsequently, as the mafic magma enters the upper part of crystal mush, it breaks up into small droplets and captures plagioclase crystals from the felsic crystal mush. The plagioclase xenocrysts enclose amphiboles crystallized at deep level and produces the poikilitic texture.
关键词	Poikilitic texture Plagioclase Magma recharge Crystal mush Quxu batholith Gangdese
英文关键词	SIERRA-NEVADA BATHOLITH; CRYSTALLIZATION; ENCLAVES; GRANITOIDS; EVOLUTION; AMPHIBOLES; ORIGIN
WOS研究方向	Geology
WOS记录号	WOS:001152994000008
来源期刊	ACTA PETROLOGICA SINICA
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283315
作者单位	China Geological Survey; Institute of Geology, Chinese Academy of Geological Sciences; Chinese Academy of Geological Sciences; China University of Geosciences - Beijing
推荐引用方式 GB/T 7714	Li Wang,Ma XuXuan,Qiu Liang,et al. Poikilitic texture of plagioclase in the Quxu batholith of the Gangdese belt, southern Tibet: Implications for magma recharge process[J],2023,39(12).
APA	Li Wang,Ma XuXuan,Qiu Liang,Si JiaLiang,&Liu DongLiang.(2023).Poikilitic texture of plagioclase in the Quxu batholith of the Gangdese belt, southern Tibet: Implications for magma recharge process.ACTA PETROLOGICA SINICA,39(12).
MLA	Li Wang,et al."Poikilitic texture of plagioclase in the Quxu batholith of the Gangdese belt, southern Tibet: Implications for magma recharge process".ACTA PETROLOGICA SINICA 39.12(2023).