Title: Determination
of primary magnetic minerals of a weathered metapelite xenolith from
Zhouba region, North China, by combining thermomagnetic runs and
low-temperature measurements
Source: CHINESE
JOURNAL OF GEOPHYSICS-CHINESE EDITION 48 (4): 876-881 JUL 2005
Document Type: Article
Language: Chinese
Abstract: We
have combined low- and high-temperature measurements for identifying
possible mineral transformations (e. g., maghemite to hematite,
titanomaghemite to magnetite) in thermomagnetic runs (magnetic
susceptibility vs. temperature) for a weathered metapelite xenolith
sample from Zhouba, North China. The results show that lab-induced
saturation isothermal remanence magnetization (SIRM) changes observed
between room temperatures and 250 degrees C, and between 280 and 380
degrees C are caused by the remanence unblocking of titanomagnetite (a
physical process) and the inversion from maghemite to hematite (a
mineralogical phase transformation), respectively. Furthermore, the
significant increase of susceptibility after 500 degrees C is
interpreted as the mineral exsolution of magnetite from
titanomaghemite. Thus, the magnetite-like Curie temperature revealed by
kappa-T curves is caused by the neoformation of magnetite.
Author Keywords: magnetic
mineralogy; thermal-magnetic experiment; lower crustal xenoliths;
Hannuoba area; Hebei Province
KeyWords Plus: HANNUOBA
BASALT; PETROLOGY; HEMATITE; SECTION; CRATON; CRUST
Addresses: Liu
QS (reprint author), China Univ Geosci, Dept Geophys, Wuhan, 430074
Peoples R China
China Univ Geosci, Dept Geophys, Wuhan, 430074 Peoples R China
Chinese Acad Sci, Inst Geodesy & Geophys, Wuhan, 430077 Peoples R
China
Univ Minnesota, Inst Rock Magnetism, Minneapolis, MN 55455 USA
China Univ Geosci, Fac Earth Sci, Wuhan, 430074 Peoples R China
Publisher: SCIENCE
PRESS, 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA
Subject Category: GEOCHEMISTRY
& GEOPHYSICS
IDS Number: 950DI
ISSN: 0001-5733
