气候变化领域集成服务门户(CCPortal): Quaternary Volcanism in Myanmar: A Record of Indian Slab Tearing in a Transition Zone From Oceanic to Continental Subduction

CCPortal

DOI	10.1029/2020GC009091
	Quaternary Volcanism in Myanmar: A Record of Indian Slab Tearing in a Transition Zone From Oceanic to Continental Subduction
	Zhang, L. Y.; Fan, W. M.; Ding, L.; Ducea, M. N.; Pullen, A.; Li, J. X.; Sun, Y. L.; Yue, Y. H.; Cai, F. L.; Wang, C.; Peng, T. P.; Sein, Kyaing
通讯作者	Zhang, LY (通讯作者)
发表日期	2020
EISSN	1525-2027
卷号	21 期号:8
英文摘要	Magmatic processes that occur during the transition from oceanic to continental subduction and collision in orogens are critical and still poorly resolved. Oceanic slab detachment in particular is hypothesized to mark a fundamental change in magmatism and deformation within an orogen. Here, we report on two Quaternary volcanic centers of Myanmar that may help us better understand the process of slab detachment. The Monywa volcanic rocks are composed of low-K tholeiitic, medium-K calk-alkaline, and high-K to shoshonitic basalts with arc signatures, while the Singu volcanic rocks show geochemical characteristics similar to asthenosphere-derived magmas. These volcanic rocks have low Os concentrations but extremely high Os-187/Os-186(i) ratios (0.1498 to 0.3824) due to minor (<4%) crustal contamination. The Monywa arc-like rocks were generated by small degrees of partial melting of subduction-modified asthenospheric mantle at variable depths from the spinel to garnet stability fields. Distinct from the Monywa arc-like rocks (Sr-87/Sr-86(i) = 0.7043 to 0.7047; epsilon Nd-i = +2.3 to +4.7), the Singu OIB-like rocks exhibit higher Sr-87/Sr-86(i) (0.7056 to 0.7064) and lower epsilon Nd-i (+0.8 to +1.6) values. These isotopic characteristics indicate a large contribution of an isotopically enriched asthenosphere layer beneath the Burmese microplate, which possibly flowed from SE Tibet. We interpret that this short-lived, small-scale, and low-degree melting Quaternary volcanism in Myanmar was triggered by its position above a slab window resulting from the tearing of the oceanic lithosphere from buoyant continental lithosphere of the Indian plate.
关键词	INDO-BURMESE WEDGE ZIRCON U-PB TIBETAN PLATEAU FORE-ARC LITHOSPHERE BENEATH TECTONIC EVOLUTION MASS-SPECTROMETRY CALC-ALKALINE MANTLE FLOW MAGMATISM
英文关键词	Myanmar Quaternary volcanism; Burmese microplate; Tibet; active slab tearing; highly oblique subduction; mantle flow
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000577130200008
来源期刊	GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/260044
推荐引用方式 GB/T 7714	Zhang, L. Y.,Fan, W. M.,Ding, L.,et al. Quaternary Volcanism in Myanmar: A Record of Indian Slab Tearing in a Transition Zone From Oceanic to Continental Subduction[J]. 中国科学院青藏高原研究所,2020,21(8).
APA	Zhang, L. Y..,Fan, W. M..,Ding, L..,Ducea, M. N..,Pullen, A..,...&Sein, Kyaing.(2020).Quaternary Volcanism in Myanmar: A Record of Indian Slab Tearing in a Transition Zone From Oceanic to Continental Subduction.GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS,21(8).
MLA	Zhang, L. Y.,et al."Quaternary Volcanism in Myanmar: A Record of Indian Slab Tearing in a Transition Zone From Oceanic to Continental Subduction".GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS 21.8(2020).