气候变化领域集成服务门户(CCPortal): Early cretaceous bimodal volcanic rocks in Wuga Co area, central tibet: The first identification of direct products derived from slab sinking in the Bangong-Nujiang suture zone

CCPortal

DOI	10.3389/feart.2023.1108655
	Early cretaceous bimodal volcanic rocks in Wuga Co area, central tibet: The first identification of direct products derived from slab sinking in the Bangong-Nujiang suture zone
	Chen, Wei; Liu, Zhibo; Wang, Nan; Wang, Genhou; Zheng, Ming; Han, Ning; Hu, Yiling; Yan, Xukun
发表日期	2023
EISSN	2296-6463
卷号	11
英文摘要	Introduction: The Bangong-Nujiang Suture Zone (BNSZ) in central Tibet is a remnant of the Bangong-Nujiang Ocean that records its entire Wilson Cycle. The model of divergent double-sided subduction (DDS) is crucial for elucidating the evolution of tectonomagmatic activity on both sides of the BNSZ and for understanding why no high-pressure metamorphic rocks occur in the BNSZ. However, the DDS geodynamics remain poorly constrained. In particular, there is a lack of reports on magmatic rocks directly associated with slab sinking in the DDS terminal stage.Methods: This study presents new geochronological, geochemical, and isotopic data for the Early Cretaceous bimodal volcanic rocks around the Wuga Co area.Results: The bimodal volcanic rocks are divided into the Wuga Co rhyolites (SiO2 = 77.0-79.0 wt%) and the Wuga Co basaltic andesites (SiO2 = 53.9-55.5 wt%). The isotopic values of the Wuga Co basaltic andesites with low (Sr-87/Sr-86)(i) values (+0.7040 to +0.7044) and high eNd(t) values (+3.8 to +4.1) lie among three endmembers (the BNO sediments in accretionary wedge, depleted mantle and the BNO slab).Discussion: These values indicate the partial melting of a mantle peridotite that interacted with the subducted slab and sediment in the accretionary wedge, which was caused by the sinking of the Bangong-Nujiang oceanic slab. The Wuga Co rhyolites (108 Ma) have low (Sr-87/Sr-86)(i) values (+0.703 to +0.706), high eNd(t) values (+2.25 to +2.49), and high eHf(t) values (+5.6 to +10.0). These values indicate that the rhyolite formed by partial melting of juvenile basaltic crust. This study also collected Hf isotope data from both sides of the BNSZ to constrain its evolution. Our results show that the eHf(t) values of magma on both sides of the BNSZ were elevated simultaneously at 130 Ma, which may be caused by the Bangong-Nujiang oceanic slab rupture. Based on these new data, we propose that the Bangong-Nujiang oceanic slab ruptured from the two overlying terranes at approximately 130 Ma and subsequently sank into the mantle at approximately 108 Ma.
关键词	bangong-nujiang collision zone bimodal volcanic rocks divergent double subduction slab sinking tibet
英文关键词	DIVERGENT DOUBLE SUBDUCTION; ASIAN OROGENIC BELT; SOUTHERN QIANGTANG; LHASA TERRANE; MAGNESIAN ANDESITES; INTRUSIVE ROCKS; CRUSTAL GROWTH; CALC-ALKALINE; MA MAGMATISM; NORTHWARD SUBDUCTION
WOS研究方向	Geosciences, Multidisciplinary
WOS记录号	WOS:000959311000001
来源期刊	FRONTIERS IN EARTH SCIENCE
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283024
作者单位	China University of Geosciences - Beijing; China Geological Survey; Chinese Academy of Geological Sciences; Chengdu University of Technology
推荐引用方式 GB/T 7714	Chen, Wei,Liu, Zhibo,Wang, Nan,et al. Early cretaceous bimodal volcanic rocks in Wuga Co area, central tibet: The first identification of direct products derived from slab sinking in the Bangong-Nujiang suture zone[J],2023,11.
APA	Chen, Wei.,Liu, Zhibo.,Wang, Nan.,Wang, Genhou.,Zheng, Ming.,...&Yan, Xukun.(2023).Early cretaceous bimodal volcanic rocks in Wuga Co area, central tibet: The first identification of direct products derived from slab sinking in the Bangong-Nujiang suture zone.FRONTIERS IN EARTH SCIENCE,11.
MLA	Chen, Wei,et al."Early cretaceous bimodal volcanic rocks in Wuga Co area, central tibet: The first identification of direct products derived from slab sinking in the Bangong-Nujiang suture zone".FRONTIERS IN EARTH SCIENCE 11(2023).