Source of highly potassic basalts in northeast China: Evidence from   Re-Os, Sr-Nd-Hf isotopes and PGE geochemistry

doi:10.1016/j.chemgeo.2013.08.007

CORC > 北京大学 > 地球与空间科学学院

	Source of highly potassic basalts in northeast China: Evidence from Re-Os, Sr-Nd-Hf isotopes and PGE geochemistry
	Chu, Zhu-Yin ; Harvey, Jason ; Liu, Chuan-Zhou ; Guo, Jing-Hui ; Wu, Fu-Yuan ; Tian, Wei ; Zhang, Yan-Long ; Yang, Yue-Heng
刊名	化工地质
	2013
关键词	Re-Os isotopes PGE Sulphide Sr-Nd-Hf isotopes Potassic basalts NE China PLATINUM-GROUP ELEMENT LITHOSPHERIC MANTLE BENEATH IONIZATION MASS-SPECTROMETRY CENOZOIC ALKALI BASALTS CARIUS TUBE DIGESTION ASIAN OROGENIC BELT MID-ATLANTIC RIDGE EASTERN CHINA NE CHINA VOLCANIC-ROCKS
DOI	10.1016/j.chemgeo.2013.08.007
英文摘要	The origin of the very young (0.5 Mato 1721 AD) Wudalianchi-Erkeshan(WDLC and EKS) highly potassic basalts in northeast (NE) China has been the subject of considerable debate. In this study, we present new major-, trace- and platinum group element (PGE) data together with Re-Os, Lu-Hf, and Sr-Nd isotopic analyses for these potassic basalts in order to further constrain their source. It has been shown that the WDLC and EKS basalts have unradiogenic to only moderately radiogenic osmium isotope ratios with Os-187/Os-188 ranging from 0.1187 to similar to 0.17, and only slight PPGE (Pt and Pd) enrichments relative to IPGE (Os, Ir and Ru). The positive correlations between Os-187/Os-188 and 1/Os suggests that these basalts have probably experienced about 2-8% of lower continental crust addition during magma ascent. On the other hand, the incorporation of sub-continental lithospheric mantle (SCLM)-derived, primary sulphides and/or PGE micro-alloys during magma ascent seems likely in some basalts, which preserve particularly unradiogenic Os compositions. The complex interplay of signatures derived from crustal and SCLM contamination means that the Os isotope systematics of the basalts do not unequivocally fingerprint the source of the WDLC and EKS basalts. The strong enrichments of light rare earth elements (LREE) and large ion lithophile elements (LILE), high-K, EM1-like Sr-Nd-Hf isotopic characteristics, and particularly strong fractionation of the heavy REE ((Sm/Yb)(N) = 9.7 +/- 0.6), suggest that the WDLC and EKS basalts mainly originated from phlogopite-bearing garnet-peridotite in the SCLM. Combined with low Ce/Pb ratios ( similar to 9.4-13.5), the most likely source of WDLC and EKS basalts is SCLM that has been metasomatized by delaminated old, lower continental crust. This is different from previous hypotheses that implicate a dominantly asthenospheric source with a contribution from delaminated ancient SCLM or subducted oceanic crust with sediments, or a SCLM source that has been metasomatized by melts derived from deep asthenosphere during the Proterozoic. (C) 2013 Elsevier B. V. All rights reserved.; Geochemistry & Geophysics; SCI(E); EI; 7; ARTICLE; 52-66; 357
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/219928]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Chu, Zhu-Yin,Harvey, Jason,Liu, Chuan-Zhou,et al. Source of highly potassic basalts in northeast China: Evidence from Re-Os, Sr-Nd-Hf isotopes and PGE geochemistry[J]. 化工地质,2013.
APA	Chu, Zhu-Yin.,Harvey, Jason.,Liu, Chuan-Zhou.,Guo, Jing-Hui.,Wu, Fu-Yuan.,...&Yang, Yue-Heng.(2013).Source of highly potassic basalts in northeast China: Evidence from Re-Os, Sr-Nd-Hf isotopes and PGE geochemistry.化工地质.
MLA	Chu, Zhu-Yin,et al."Source of highly potassic basalts in northeast China: Evidence from Re-Os, Sr-Nd-Hf isotopes and PGE geochemistry".化工地质 (2013).