Geochronological, geochemical, and Sr-Nd-Hf isotopic studies of the Aketas adakitic granites in Eastern Junggar: Petrogenesis and tectonic implications

Geochronological, geochemical, and Sr-Nd-Hf isotopic studies of the Aketas adakitic granites in Eastern Junggar: Petrogenesis and tectonic implications

CHEN ZHANG; QUN LUO; XIN ZHANG; LUOFU LIU; DONGDONG LIU; PENGFEI WANG; KEJI YANG; JIAN WANGYAN ZHAO

2018

发表期刊

Geological Journal

卷号

53 期号:1 页码:80-101

摘要

The Aketas adakitic granites are located in the Dulate Arc, in the northern part of the eastern Junggar region, Xinjiang (NW China). In this study, we determined the zircon U-Pb isotopic compositions, bulk-rock Sr-Nd-Hf isotopic compositions, and major and trace elements of Aketas granite samples. These samples show a narrow range in SiO2 content (65.05-67.19wt.%) as well as high Al2O3 (14.95-18.09wt.%; A/CNK=0.96-1.08), Na2O+K2O (7.94-8.42wt.%), and CaO (2.05-3.48wt.%) content. Similar to modern adakites, the samples have high Na2O (4.55-5.61wt.%) and Sr (554.00-915.00ppm) content, high Sr/Y ratios (85.10-127.38), and low Y (6.51-7.12ppm) and Yb (0.42-0.79ppm) content. The low initial Sr-87/Sr-86 ratios (0.70298-0.70350) and positive epsilon Nd(t) (+5.1 to +7.0) and epsilon Hf(t) values (+10.4 to +14.9) suggest that the Aketas adakitic granites were derived from the partial melting of lower crustal material in a subduction setting. This is further evidenced by high Mg# values (42.00-65.67), high SiO2 and K2O content, and low Cr (<17.30ppm), Co (<9.62ppm), and Ni (<12.60ppm) content. Bidirectional subduction occurred between eastern Junggar and the Altai Orogen during the Late Carboniferous, and in combination with other exposed Palaeozoic granites in eastern Junggar, the Aketas adakitic granites may represent the latest record of this subduction event. The emplacement of the Aketas adakitic granites implies that eastern Junggar was involved in southward subduction at 308 +/- 2.3Ma; therefore, the final collision between the Siberian and Kazakhstan blocks likely occurred between 310.3 and 307Ma.

关键词

Central Asian Orogenic Belt Aketas Adakitic Granites Sr–nd–hf Isotopes Zircon U–pb Dating Tectonic Evolution Bidirectional Subduction

收录类别

SCI

语种

英语

文献类型

期刊论文

条目标识符

http://ir.gyig.ac.cn/handle/42920512-1/8646

专题

地球内部物质高温高压实验室

作者单位

1.State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, China
2.Basin and Reservoir Research Center, China University of Petroleum, Beijing, China
3.Unconventional Natural Gas Institute, China University of Petroleum, Beijing, China
4.Key Laboratory of High-temperature and High-pressure Study of the Earth’s Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China

推荐引用方式
GB/T 7714

CHEN ZHANG;QUN LUO;XIN ZHANG;LUOFU LIU;DONGDONG LIU;PENGFEI WANG;KEJI YANG;JIAN WANGYAN ZHAO. Geochronological, geochemical, and Sr-Nd-Hf isotopic studies of the Aketas adakitic granites in Eastern Junggar: Petrogenesis and tectonic implications[J]. Geological Journal,2018,53(1):80-101.

APA

CHEN ZHANG;QUN LUO;XIN ZHANG;LUOFU LIU;DONGDONG LIU;PENGFEI WANG;KEJI YANG;JIAN WANGYAN ZHAO.(2018).Geochronological, geochemical, and Sr-Nd-Hf isotopic studies of the Aketas adakitic granites in Eastern Junggar: Petrogenesis and tectonic implications.Geological Journal,53(1),80-101.

MLA

CHEN ZHANG;QUN LUO;XIN ZHANG;LUOFU LIU;DONGDONG LIU;PENGFEI WANG;KEJI YANG;JIAN WANGYAN ZHAO."Geochronological, geochemical, and Sr-Nd-Hf isotopic studies of the Aketas adakitic granites in Eastern Junggar: Petrogenesis and tectonic implications".Geological Journal 53.1(2018):80-101.