Geomagnetic palaeointensity just prior to the Cretaceous normal superchron

	Geomagnetic palaeointensity just prior to the Cretaceous normal superchron
	Zhu, RX ; Pan, YX ; Shaw, J ; Li, DM ; Li, Q
刊名	PHYSICS OF THE EARTH AND PLANETARY INTERIORS
	2001-12-10
卷号	128 期号:1-4 页码:207-222
关键词	palaeointensities M0 China lavas
ISSN号	0031-9201
文献子类	Article
英文摘要	A combined geochronologic (K-Ar) and palaeomagnetic study has been conducted on abasalt lava sequence at Zhuanchengzi in Liaoning province, northeastern China. The new K-Ar age obtained from these lava flows is 120.93 +/- 0.88 Ma (marine anomaly MO). Detailed investigations were conducted on two samples from each lava flow to determine their rock-magnetic properties. The temperature dependences of the saturation magnetization (J-T) and the initial susceptibility (K-T) show evidence of low-titanium magnetite and a Curie temperature of 560-585 degreesC with generally good reversibility of heating and cooling curves. Hysteretic properties, ratios of M-rs/M-s and Her/Hc, indicate that pseudo-single-domain (PSD) grains of magnetite are dominant in these lavas. Stepwise thermal demagnetization isolated well-defined characteristic magnetization (ChRM) in all the 20 lava flows with a mean direction of D/I = 174.9/-60.1 degrees with alpha (95) = 2.3 degrees. The modified version of the Thellier and Thellier palaeointensity method (Coe, 1967a) with systematic partial thermoremanent magnetization (pTRM) checks was used. Forty-two of 71 samples (59%) yielded reliable palaeointensity results. Virtual dipole moment (VDM) values range from 1.71 X 10(22) to 5.27 x 10(22) A m(2) with an average of (3.96 +/- 0.07) x 10(22) A m(2). This low dipole-field intensity value is approximately half the present day VDM, consistent with older results obtained from the Caribbean submarine basalt glasses for the period of 125 +/- 1 Ma (Pick and Tauxe, 1993). This suggested that a weak geomagnetic field probably occurred just prior to the Cretaceous normal superchron (CNS). (C) 2001 Elsevier Science B.V. All rights reserved.
WOS关键词	EARTHS MAGNETIC-FIELD ; LAVA FLOWS ; DIPOLE LOW ; PALEOINTENSITY ; INTENSITY ; ISLAND ; CHINA ; REVERSALS ; HAWAII ; MANTLE
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000173024300016
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/77051]
专题	中国科学院地质与地球物理研究所
通讯作者	Zhu, RX
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100101, Peoples R China 2.Univ Liverpool, Dept Earth Sci, Liverpool L69 7ZE, Merseyside, England 3.China Seismol Bur, Inst Geol, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Zhu, RX,Pan, YX,Shaw, J,et al. Geomagnetic palaeointensity just prior to the Cretaceous normal superchron[J]. PHYSICS OF THE EARTH AND PLANETARY INTERIORS,2001,128(1-4):207-222.
APA	Zhu, RX,Pan, YX,Shaw, J,Li, DM,&Li, Q.(2001).Geomagnetic palaeointensity just prior to the Cretaceous normal superchron.PHYSICS OF THE EARTH AND PLANETARY INTERIORS,128(1-4),207-222.
MLA	Zhu, RX,et al."Geomagnetic palaeointensity just prior to the Cretaceous normal superchron".PHYSICS OF THE EARTH AND PLANETARY INTERIORS 128.1-4(2001):207-222.