Geochemical characteristics of the intra-oceanic arc type metabasic-volcanics in Chencai accretion complex of Zhejiang Province and their geological significance

DONG Xue-fa; YU Sheng-qiang; TANG Zeng-cai; XIAO Qing-hui; YUAN Qiang; CHEN Zhong-da; ZHOU Zong-yao; WU Xiao-yong

doi:10.12029/gc20160309

2016 Vol. 43, No. 3

Article Contents

Article navigation > Geology in China > 2016 > (3): 817-828

Next Article Previous Article

DONG Xue-fa, YU Sheng-qiang, TANG Zeng-cai, XIAO Qing-hui, YUAN Qiang, CHEN Zhong-da, ZHOU Zong-yao, WU Xiao-yong. Geochemical characteristics of the intra-oceanic arc type metabasic-volcanics in Chencai accretion complex of Zhejiang Province and their geological significance[J]. Geology in China, 2016, (3): 817-828. doi: 10.12029/gc20160309

Citation:

DONG Xue-fa, YU Sheng-qiang, TANG Zeng-cai, XIAO Qing-hui, YUAN Qiang, CHEN Zhong-da, ZHOU Zong-yao, WU Xiao-yong. Geochemical characteristics of the intra-oceanic arc type metabasic-volcanics in Chencai accretion complex of Zhejiang Province and their geological significance[J]. Geology in China, 2016, (3): 817-828. doi: 10.12029/gc20160309

Geochemical characteristics of the intra-oceanic arc type metabasic-volcanics in Chencai accretion complex of Zhejiang Province and their geological significance

1.
China University of Geosciences, Beijing 100083, China;Zhejiang Institute of Geological Survey, Hangzhou 311203, Zhejiang, China
2.
Zhejiang Institute of Geological Survey, Hangzhou 311203, Zhejiang, China
3.
Development and Research Center of China Geological Survey, Beijing 100037, China

Received Date: 20 January 2016

Revised Date: 12 February 2016

Publish Date: 24 June 2016

Abstract

Abstract

This paper reports the discovery of a special kind of metabasic-volcanics combination in Chenccai accretion complex of Zhejiang Province. It is mainly composed of amphibolite and hornblendite. Geochemical characteristics of the rocks are low Ti and high Mg. Their protoliths are tholeiite and calcalkali basalts. The rocks have low values of REE, and the average REE is 25.46×10-6. The ratios of LREE to HREE and LaN toYbN are lower, and the average of the ratios are respectively 1.87 and 1.30. The average of δ (Eu)is 0.97. The REE distribution model is similar to N-MORB and T-MORB. Trace elements show enrichment of incompatible elements Cr, Ni and LILE such as K, Rb, Ba and U and depleted in HFSE such as Nb, Zr, P and Ti. The geochemical characteristics are very similar to those of boninites. The ratios and discrimination diagrams of trace elements indicate that the metabasic-volcanics were formed in an intra oceanic arc. The discovery of the intra oceanic arc type metabasic- volcanics shows that Chencai Group resulted most probably from the subducted accretionary complex which contained ancient fragments of oceanic crust from the middle Neoproterozoic to early Paleozoic rather than the Cathaysia Block basement.
- intra oceanic arc /
- metabasic-volcanics /
- Chencai accretion complex /
- geochemistry /
- Zhejiang