Lithospheric extension in response to subduction of the Paleo-Pacific Plate: Insights from Early Jurassic intraplate volcanic rocks in the Sk2 Borehole, Songliao Basin, NE China

被引：29

作者：

Huang, Feng ^{[1
,2
]}

Zhang, Zhao ^{[1
,2
]}

Xu, Jifeng ^{[1
,2
,3
]}

Li, Xiyao ^{[4
]}

Zeng, Yunchuan ^{[1
,2
]}

Xu, Rong ^{[5
]}

Liu, Xijun ^{[3
]}

Zhang, Liying ^{[1
,2
]}

Zhang, Man ^{[1
,2
]}

Yang, Changqi ^{[1
,2
]}

Zhang, Liangliang ^{[6
]}

Yu, Hongxia ^{[3
]}

Yang, Xuli ^{[1
,2
]}

机构：

[1] China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China

[2] China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China

[3] Guilin Univ Technol, Guangxi Key Lab Hidden Met Ore Deposits Explorat, Guilin 541004, Peoples R China

[4] Ocean Univ China, Coll Marine Geosci, Key Lab Submarine Geosci & Prospecting Tech, MOE, Qingdao 266100, Peoples R China

[5] China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Peoples R China

[6] China Univ Geosci, Inst Earth Sci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China

来源：

LITHOS | 2021年 / 380卷

基金：

中国国家自然科学基金;

关键词：

Sk2; borehole; Intraplate mafic magmatism; Paleo-Pacific plate subduction; Tectonic evolution; Early Jurassic; NE China; ASIAN OROGENIC BELT; U-PB CHRONOLOGY; LA-ICP-MS; MONGOL-OKHOTSK; TECTONIC IMPLICATIONS; ACCRETIONARY COMPLEX; ZHANGGUANGCAI RANGE; INTRUSIVE ROCKS; TRACE-ELEMENTS; SLAB BREAKOFF;

D O I：

10.1016/j.lithos.2020.105871

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

Subduction of the Paleo-Pacific and Mongol-Okhotsk oceanic plates is widely believed to have caused extensive Mesozoic magmatism and lithospheric deformation in East Asia. However, it remains unclear how the two tectonic domains affected NE China, and whether a boundary exists between them, because the Songnen Block in central NE China is covered by sedimentary rocks and the related mafic magmatism has been rarely discovered. Here we report a suite of Early Jurassic (ca. 175 Ma) mafic volcanic rocks (including basalt and basaltic andesite) from the Sk2 Borehole, Songliao Basin, NE China. The Sk2 mafic rocks are characterized by high Th/U, Zr/Y and Ti/ Y ratios, and their geochemical signatures are consistent with formation in a back-arc extensional setting, rather than an arc setting. The rocks show depleted zircon epsilon(Hf)(t) and whole-rock epsilon(Nd)(t) values, which are comparable to mafic rocks located on the east of the Songliao Basin. This suggests that they both have a depleted mantle source, unlike the mafic rocks on the west of the Songliao Basin with relatively enriched Nd and Hf isotopes. Early-Middle Jurassic mafic rocks are distributed in the Erguna Block, >500 km to the west from the Sk2 Borehole, whereas coeval mafic rocks are widely distributed in the nearby eastern Heilongjiang and Jilin provinces. These intraplatelike mafic rocks and the Early Jurassic bimodal rocks within the Lesser Xing'an and Zhangguangcai ranges likely formed in response to lithospheric extension that was triggered by subduction of the Paleo-Pacific Plate. The Early Jurassic mafic rocks directly underlie the oldest sedimentary rocks (the Huoshiling Formation) in the Songliao Basin, which suggests that basin formation was probably initiated by lithospheric extension. (C) 2020 Elsevier B.V. All rights reserved.

引用

页数：14