Magnetic fabric and paleomagnetism of the Middle Triassic siliciclastic rocks from the Nanpanjiang Basin, South China: Implications for sediment provenance and tectonic process

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	Magnetic fabric and paleomagnetism of the Middle Triassic siliciclastic rocks from the Nanpanjiang Basin, South China: Implications for sediment provenance and tectonic process
	Cai, JX ; Tan, XD ; Wu, Y
刊名	JOURNAL OF ASIAN EARTH SCIENCES
	2014
卷号	80 页码:134-147
关键词	South China block Nanpanjiang Basin Siliciclastic rocks Paleoflow Provenance
ISSN号	1367-9120
通讯作者	Caijianxin.student@sina.com
中文摘要	A combined magnetic fabric and paleomagnetic study has been carried out on the siliciclastic rocks gathered from a stratigraphic cross-section through the Nanpanjiang Basin, South China, in an attempt to extract the paleoflow information preserved in and, thus, constrain the possible origins of these clastic rocks. The sediments used for this study were formed by sediment-gravity flows along the southern margin of the South China block in the Middle Triassic time (ca. 245-228 Ma). The results show a normal distribution of both low field magnetic susceptibility values and natural remanent magnetization intensities, which along with the monotonic detrital framework mode, mainly comprising quartz and lithic particles, may suggest a single provenance involved in deposition of these clastic deposits. Anisotropy of magnetic susceptibility (AMS) analysis acquires primarily the sedimentary magnetic fabrics, which, in this study, reveal paleoflow directions ranging from NNW to ENE with an overall mean orientation of NE. Demagnetization on a part of samples isolates a characteristic remanent component averaged at D = 44.8 degrees, I= 16.9 degrees, K = 9.7, alpha(95) = 6. 5 degrees, n = 55, corresponding to a paleolatitude N8.6 degrees and a clockwise rotation of ca. 45 degrees since the Middle Triassic for the studied cross-section. This mean direction passes fold tests and is consistent with the reference direction expected from the South China block at the 95% confidence level. Restoring this similar to 45 degrees declination renders an overall northward paleoflow, which, combined with other evidence, suggests a southern provenance for these sediments during deposition in the Middle Triassic time. In terms of the early Mesozoic plate framework of southeastern Asia, a tectonic scenario is proposed here, whereby the nearly N-S convergence of the Indochina and South China blocks and its related Indosinian orogeny in the Middle Triassic caused the formation of the Nanpanjiang foreland basin, which was filled by voluminous detritus shed from the uplifted orogenic belt on its southern side. (C) 2013 Elsevier Ltd. All rights reserved.
学科主题	Geology
收录类别	SCI
资助信息	Marginal Sea Opening Foundation [MSGL 12-06]; National Science Foundation for Young Scholars of China [41202149]
原文出处	PERGAMON-ELSEVIER SCIENCE LTD
WOS记录号	WOS:000331154800010
公开日期	2014-12-11
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/10648]
专题	南海海洋研究所_中科院边缘海地质重点实验室
推荐引用方式 GB/T 7714	Cai, JX,Tan, XD,Wu, Y. Magnetic fabric and paleomagnetism of the Middle Triassic siliciclastic rocks from the Nanpanjiang Basin, South China: Implications for sediment provenance and tectonic process[J]. JOURNAL OF ASIAN EARTH SCIENCES,2014,80:134-147.
APA	Cai, JX,Tan, XD,&Wu, Y.(2014).Magnetic fabric and paleomagnetism of the Middle Triassic siliciclastic rocks from the Nanpanjiang Basin, South China: Implications for sediment provenance and tectonic process.JOURNAL OF ASIAN EARTH SCIENCES,80,134-147.
MLA	Cai, JX,et al."Magnetic fabric and paleomagnetism of the Middle Triassic siliciclastic rocks from the Nanpanjiang Basin, South China: Implications for sediment provenance and tectonic process".JOURNAL OF ASIAN EARTH SCIENCES 80(2014):134-147.