Oxygen and lead isotope characteristics of granitic rocks from the Nansha block (South China Sea): Implications for their petrogenesis and tectonic affinity

doi:10.1111/j.1440-1738.2010.00754.x

	Oxygen and lead isotope characteristics of granitic rocks from the Nansha block (South China Sea): Implications for their petrogenesis and tectonic affinity
	Yan, Quanshu 1,2; Shi, Xuefa 1; Li, Naisheng 1
刊名	ISLAND ARC
	2011-06
卷号	20 期号:2 页码:150-159
关键词	geochemistry granitic rock Mesozoic era Nansha microblock petrogenesis South China Sea
ISSN号	1038-4871
DOI	10.1111/j.1440-1738.2010.00754.x
英文摘要	The pre-Cenozoic history of the South China Sea (SCS) region is the object of continued debate. To trace the evolution of the SCS, a better understanding of the petrogenesis and tectonic affiliation of the granitic rocks that comprise the microblocks within the region is necessary. In this study, we analyzed the whole-rock oxygen and lead isotope ratios of granitic samples dredged from two locations in the Nansha microblock, one of the microblocks in the SCS. Oxygen isotope data combined with previously published Sr isotope data show that group I rocks (delta 18O = 6.00-7.20 parts per thousand; average = 6.64 parts per thousand) originated from a mantle source contaminated by material and/or fluid input from a Mesozoic subduction zone in the southeastern side of the microblock. Group II rocks (delta 18O = 6.86 parts per thousand-9.13 parts per thousand; average = 7.75 parts per thousand) also came from the same source, but they were additionally affected by crustal contamination. The Nansha microblock has high radiogenic lead ratios (206Pb/204Pb(i) = 18.602-18.756, 207Pb/204Pb(i) = 15.660-15.713, 208Pb/204Pb(i) = 38.693-38.893), which indicate that the Nansha microblock is tectonically affiliated with the Nanling-Hainan or South China block. This notion is consistent with the results of a previous Nd isotope study. As a whole, results of our study suggest that some of the other microblocks dispersed in the SCS are also possible fragments of South China block, and thus further studies are needed to better constrain the pre-Cenozoic evolutionary history of the SCS region.
资助项目	China Postdoctoral Science Foundation of Shandong Province[200802007]
WOS关键词	MESOZOIC IGNEOUS ROCKS ; SOUTHEASTERN CHINA ; U-PB ; EVOLUTION ; TAIWAN ; MODEL ; ASIA ; ND ; GEOCHRONOLOGY ; CONSTRAINTS
WOS研究方向	Geology
语种	英语
出版者	WILEY-BLACKWELL
WOS记录号	WOS:000291043400001
内容类型	期刊论文
源URL	[http://ir.fio.com.cn:8080/handle/2SI8HI0U/26923]
专题	自然资源部第一海洋研究所
通讯作者	Shi, Xuefa
作者单位	1.State Ocean Adm, Inst Oceanog 1, Key Lab Marine Sedimentary & Environm Geol, Qingdao 266061, Peoples R China 2.UCSD, Scripps Inst Oceanog, La Jolla, CA 92093 USA
推荐引用方式 GB/T 7714	Yan, Quanshu,Shi, Xuefa,Li, Naisheng. Oxygen and lead isotope characteristics of granitic rocks from the Nansha block (South China Sea): Implications for their petrogenesis and tectonic affinity[J]. ISLAND ARC,2011,20(2):150-159.
APA	Yan, Quanshu,Shi, Xuefa,&Li, Naisheng.(2011).Oxygen and lead isotope characteristics of granitic rocks from the Nansha block (South China Sea): Implications for their petrogenesis and tectonic affinity.ISLAND ARC,20(2),150-159.
MLA	Yan, Quanshu,et al."Oxygen and lead isotope characteristics of granitic rocks from the Nansha block (South China Sea): Implications for their petrogenesis and tectonic affinity".ISLAND ARC 20.2(2011):150-159.