emplacementageandtectonicimplicationsofthebrecciatedlimestoneattheedgeofthelongmenshanklippe

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	emplacementageandtectonicimplicationsofthebrecciatedlimestoneattheedgeofthelongmenshanklippe
	Xue Zhenhua 1; Shang Qinghua 2; Jiang Wenying 1; Wang Qingchen 1; Li Shuangjian 3
刊名	sciencechinaearthsciences
	2016
卷号	59 期号:3 页码:590
ISSN号	1674-7313
英文摘要	The Longmenshan thrust belt (LMTB) is one of the best natural laboratories for thin-skinned tectonics and has developed a series of NE-SW trending fold-and-thrust structures represented by a series of nappes and klippes, exemplified by the Tangbazi and Bailuding klippe. However, the timing and emplacement mechanism of these klippes are still in dispute. Three possible mechanisms have been proposed: (1) a Mesozoic-Cenozoic southeastward thrusting, (2) a Cenozoic gravity gliding, and (3) glacial deposition. Almost all of these klippes are tectonic and overlaid on folded Late Triassic sandstone except the Tangbazi klippe, which is located in the center of the LMTB and has a narrow tail extending southeastward and covering Jurassic-Quaternary rocks. This geometric relationship is considered the most important stratigraphic evidence to support the post-Cenozoic emplacement of the Longmenshan klippe. Our structural and petrological observations show that the rocks at the front of the Tangbazi and Bailuding structures are brecciated limestone, which is assumed to have been generated by a gravitational collapse and is not characteristic of the massive Permian strata. Artemisia pollen, which has been exclusively recognized in post-Late Eocene strata in Central Asia, was found in the matrix of this brecciated limestone. Therefore, our discovery indicates that the brecciated limestone was deposited after the Late Eocene rather than during the Permian as annotated on the geological map. In contrast, unbrecciated, massive Permian limestone overlaid on the folded Late Triassic rocks. Hence, the anomalous relationship of Permian strata overlaying Late Triassic rocks cannot be evidence of Cenozoic emplacement. According to currently recognized bulk strata relationships, we can only be sure that the klippe was emplaced in the post Late Triassic. The petrological characteristics of the brecciated limestone show that it was crumbled before the re-sedimentation of the breccia, implying that the LMTB might have experienced a rapid uplift during the Late Eocene.
语种	英语
内容类型	期刊论文
源URL	[http://119.78.100.205/handle/311034/16349]
专题	古脊椎动物与古人类研究所_图书馆1
作者单位	1.中国科学院地质与地球物理研究所 2.中国科学院古脊椎动物与古人类研究所 3.Institute of Petroleum Exploration and Development, China Petroleum and Chemical Corporation
推荐引用方式 GB/T 7714	Xue Zhenhua,Shang Qinghua,Jiang Wenying,et al. emplacementageandtectonicimplicationsofthebrecciatedlimestoneattheedgeofthelongmenshanklippe[J]. sciencechinaearthsciences,2016,59(3):590.
APA	Xue Zhenhua,Shang Qinghua,Jiang Wenying,Wang Qingchen,&Li Shuangjian.(2016).emplacementageandtectonicimplicationsofthebrecciatedlimestoneattheedgeofthelongmenshanklippe.sciencechinaearthsciences,59(3),590.
MLA	Xue Zhenhua,et al."emplacementageandtectonicimplicationsofthebrecciatedlimestoneattheedgeofthelongmenshanklippe".sciencechinaearthsciences 59.3(2016):590.