Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron

doi:10.1016/S0031-9201(03)00034-7

	Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron
	Zhu, RX ; Hoffman, KA ; Pan, YX ; Shi, RP ; Li, DM
刊名	PHYSICS OF THE EARTH AND PLANETARY INTERIORS
	2003-04-30
卷号	136 期号:3-4 页码:187-199
关键词	palaeointensities Cretaceous normal superchron China lavas Thellier method
ISSN号	0031-9201
DOI	10.1016/S0031-9201(03)00034-7
文献子类	Article
英文摘要	A palaeomagnetic and geochronologic investigation has been carried out on a sequence of 19 lava flows at Sihetun in northeastern China. Age determinations by K/Ar dating indicate that the sequence spans 124-133 Ma, that is, the time just prior to Cretaceous normal superchron (CNS). Rock magnetic measurements of thermomagnetic curves and hysteresis loops show the primary carrier of remanence to be pseudo-single domain magnetite. Stepwise thermal demagnetization successfully isolated a well-defined direction of characteristic magnetization (ChRM) in all the lavas. The mean palaeodirection determined is D/I = 5.4degrees/58.7degrees (alpha(95) = 2.4degrees) and D/I = 175.9degrees/-60.0degrees (alpha(95) = 6.4degrees) for 15 normally magnetized flows and 3 reversely magnetized flows, respectively. One lava was found to possess an intermediate direction of magnetization. The inferred palaeolatitude of the sampling site is very similar to the present-day position, supporting the contention that suturing between the Mongolia and north China plates was probably completed by the Late Jurassic, and that subsequently little rotation or translation occurred in the region west of the Tanlu fault zone. Thellier-Thellier palaeointensity experiments with systematic partial thermoremanent magnetization (pTRM) checks were conducted on 66 samples from 13 lava flows. Results from the 29 samples (44%) which met strict reliability criteria indicate a range of virtual dipole moments (VDMs) from 2.83 to 4.17 x 10(22) A m(2) with an average of (3.53 +/- 0.02) X 10(22) A m(2). This finding helps confirm that a weak geomagnetic field probably occurred just prior to the CNS. (C) 2003 Elsevier Science B.V. All rights reserved.
WOS关键词	EARTHS MAGNETIC-FIELD ; PALEO-INTENSITIES ; THELLIER ANALYSES ; MANTLE PLUMES ; PALEOINTENSITIES ; REVERSAL ; PACIFIC ; HAWAII ; ISLAND ; CHINA
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000184329100005
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/78122]
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, Palaeomagnetism Lab, Inst Geol & Geophys, Beijing 100029, Peoples R China 2.Calif Polytech State Univ San Luis Obispo, Dept Phys, San Luis Obispo, CA 93407 USA 3.China Seismol Bur, Inst Geol, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Zhu, RX,Hoffman, KA,Pan, YX,et al. Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron[J]. PHYSICS OF THE EARTH AND PLANETARY INTERIORS,2003,136(3-4):187-199.
APA	Zhu, RX,Hoffman, KA,Pan, YX,Shi, RP,&Li, DM.(2003).Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron.PHYSICS OF THE EARTH AND PLANETARY INTERIORS,136(3-4),187-199.
MLA	Zhu, RX,et al."Evidence for weak geomagnetic field intensity prior to the Cretaceous normal superchron".PHYSICS OF THE EARTH AND PLANETARY INTERIORS 136.3-4(2003):187-199.