气候变化领域集成服务门户(CCPortal): Paleomagnetism of Paleocene-Maastrichtian (60–70 Ma) Lava Flows From Tian Shan (Central Asia): Directional Analysis and Paleointensities

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DOI	10.1029/2019JB018631
	Paleomagnetism of Paleocene-Maastrichtian (60–70 Ma) Lava Flows From Tian Shan (Central Asia): Directional Analysis and Paleointensities
	Meng J.; Lhuillier F.; Wang C.; Liu H.; Eid B.; Li Y.
发表日期	2020
ISSN	21699313
卷号	125 期号:9
英文摘要	The Tuoyun volcanics from the Tian Shan range (Central Asia) give an opportunity to investigate the variability of the Earth's magnetic field during the Cretaceous and Early Paleogene. In the paper we focus on Maastrichtian-Paleocene basalts and report new paleomagnetic results from 70 lava flows (respectively 45 directional groups) sampled near Tuoyun village (75.33°E; 40.18°N) from three distinct sections. Combined with previous results, our new data set yields a virtual geomagnetic pole at φS = 180.2°E, ϑS = 49.5°N with an angular standard deviation (Formula presented.) (for N = 93 directional groups). The mean inclination Is = 36.2° is indicative of an emplacement of the Tuoyun volcanics at a paleolatitude around 20°N, consistent with the high dispersion k = 14.6 of the directions. Such an inclination value is 10–15° lower than the predictions from the apparent polar wander paths for stable Europe and East Asia. This observation can be partly explained by crustal shortening within the East Asian plate during the India-Asia convergence, but also needs to invoke a local field anomaly in Central Asia as previously proposed. Our absolute paleointensity experiments conducted on two lava flows and two baked sedimentary layers yield a mean virtual dipole moment of 58.9 ± 6.9 ZA·m2, consistent with the values at 60–70 Ma in the global paleointensity database. Compared to relative paleointensity results during the Cretaceous Normal Superchron and during the Plio-Pleistocene, the relative variability in intensity—supposed to be a proxy for the geodynamo's activity—estimated here at 31 ± 5% (N = 15) from pseudo-Thellier experiments possibly corroborates a correlation between geomagnetic reversal frequency and paleosecular variation rate during the past 120 Myr. ©2020. The Authors.
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187628
作者单位	State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences, Beijing, China; Department of Earth and Environmental Sciences, Ludwig Maximilian University, Munich, Germany; State Key Laboratory of Paleobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, Nanjing, China; School of Ocean Sciences, China University of Geosciences, Beijing, China
推荐引用方式 GB/T 7714	Meng J.,Lhuillier F.,Wang C.,等. Paleomagnetism of Paleocene-Maastrichtian (60–70 Ma) Lava Flows From Tian Shan (Central Asia): Directional Analysis and Paleointensities[J],2020,125(9).
APA	Meng J.,Lhuillier F.,Wang C.,Liu H.,Eid B.,&Li Y..(2020).Paleomagnetism of Paleocene-Maastrichtian (60–70 Ma) Lava Flows From Tian Shan (Central Asia): Directional Analysis and Paleointensities.Journal of Geophysical Research: Solid Earth,125(9).
MLA	Meng J.,et al."Paleomagnetism of Paleocene-Maastrichtian (60–70 Ma) Lava Flows From Tian Shan (Central Asia): Directional Analysis and Paleointensities".Journal of Geophysical Research: Solid Earth 125.9(2020).