Experimental test of the cooling rate effect on blocking temperatures in stepwise thermal demagnetization
文献类型：期刊论文
| 作者 | Berndt, Thomas A.2; Chang, Liao3; Paterson, Greig A.1,5; Cao, Changqian1,4 |
| 刊名 | GEOPHYSICAL JOURNAL INTERNATIONAL
 |
| 出版日期 | 2021-02-01 |
| 卷号 | 224期号:2页码:1117-1127 |
| 关键词 | Magnetic mineralogy and petrology Palaeointensity Palaeomagnetism Remagnetization Rock and mineral magnetism |
| ISSN号 | 0956-540X |
| DOI | 10.1093/gji/ggaa514 |
| 英文摘要 | Upon cooling, most rocks acquire a thermoremanent magnetization (TRM); the cooling rate at which this happens not only affects palaeointensity estimates, but also their unblocking temperatures in stepwise thermal demagnetization experiments, which is important, for example, to estimate volcanic emplacement temperatures. Traditional single-domain (SD) theory of magnetic remanence relates relaxation times to blocking temperatures- the blocking temperature is the temperature at which the relaxation time becomes shorter than the experimental timescale-and therefore strictly only applies to remanence acquisition mechanisms at constant temperatures (i.e. viscous remanent magnetizations, VRMs). A theoretical framework to relate (constant) blocking temperatures to (time-varying) cooling rates exists, but this theory has very limited experimental verification-partly due to the difficulty of accurately knowing the cooling rates of geological materials. Here we present an experimental test of this 'cooling rate effect on blocking temperatures' through a series of demagnetization experiments of laboratory-induced TRMs with controlled cooling rates. The tested cooling rates span about 1 order of magnitude and are made possible through (1) extremely accurate demagnetization experiments using a low-temperature magnetic properties measurement system (MPMS) and (2) the use of a '1-step-only' stepwise thermal demagnetization protocol where the relaxation process is measured over time. In this way the relaxation time corresponding to the blocking temperature is measured, which can be done to much higher accuracy than measuring the blocking temperature directly as done in traditional stepwise thermal demagnetization experiments. Our experiments confirm that the cooling rate relationship holds to high accuracy for ideal magnetic recorders, as shown for a synthetic weakly interacting SD magnetoferritin sample. A SD-dominated low-Ti titanomagnetite Tiva Canyon Tuff sample, however, showed that natural samples are unlikely to be sufficiently 'ideal' to meet the theoretical predictions to high accuracy the experimental data agrees only approximately with the theoretical predictions, which may potentially affect blocking temperature estimates in stepwise thermal demagnetization experiments. Moreover, we find a strongly enhanced cooling rate effect on palaeointensities for even marginally non-ideal samples (up to 43 per cent increase in pTRM for a halving of the cooling rate). |
| 资助项目 | Boya Post-doctoral fellowship - Peking University ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; National Natural Science Foundation of China (NSFC)[41574063] ; Natural Environmental Research Council (NERC) Independent Research Fellowship[NE/P017266/1] ; NSFC[41774076] ; NSFC[41722402] ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; University of Minnesota |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000613273500022 |
| 出版者 | OXFORD UNIV PRESS |
| 资助机构 | Boya Post-doctoral fellowship - Peking University ; Boya Post-doctoral fellowship - Peking University ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; National Natural Science Foundation of China (NSFC) ; National Natural Science Foundation of China (NSFC) ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; NSFC ; NSFC ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; University of Minnesota ; University of Minnesota ; Boya Post-doctoral fellowship - Peking University ; Boya Post-doctoral fellowship - Peking University ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; National Natural Science Foundation of China (NSFC) ; National Natural Science Foundation of China (NSFC) ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; NSFC ; NSFC ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; University of Minnesota ; University of Minnesota ; Boya Post-doctoral fellowship - Peking University ; Boya Post-doctoral fellowship - Peking University ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; National Natural Science Foundation of China (NSFC) ; National Natural Science Foundation of China (NSFC) ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; NSFC ; NSFC ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; University of Minnesota ; University of Minnesota ; Boya Post-doctoral fellowship - Peking University ; Boya Post-doctoral fellowship - Peking University ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; Institute for Rock Magnetism (IRM) Visiting Researcher Fellowship ; National Natural Science Foundation of China (NSFC) ; National Natural Science Foundation of China (NSFC) ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; Natural Environmental Research Council (NERC) Independent Research Fellowship ; NSFC ; NSFC ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; Instrumentation and Facilities program of the National Science Foundation, Earth Sciences Division ; University of Minnesota ; University of Minnesota |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/100055]  |
| 专题 | 地质与地球物理研究所_中国科学院地球与行星物理重点实验室 |
| 通讯作者 | Berndt, Thomas A. |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, Paleomagnetism & Geochronol Lab, Key Lab Earth & Planetary Phys,Biogeornagnetism G, Beijing 100029, Peoples R China 2.Peking Univ, Sch Earth & Space Sci, Dept Geophys, Beijing 100871, Peoples R China 3.Peking Univ, Sch Earth & Space Sci, Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China 4.Chinese Acad Sci, Innovat Acad Earth Sci, Beijing 100029, Peoples R China 5.Univ Liverpool, Dept Earth Ocean & Ecol Sci, Liverpool L69 7ZE, Merseyside, England |
| 推荐引用方式 GB/T 7714 | Berndt, Thomas A.,Chang, Liao,Paterson, Greig A.,et al. Experimental test of the cooling rate effect on blocking temperatures in stepwise thermal demagnetization[J]. GEOPHYSICAL JOURNAL INTERNATIONAL,2021,224(2):1117-1127. |
| APA | Berndt, Thomas A.,Chang, Liao,Paterson, Greig A.,&Cao, Changqian.(2021).Experimental test of the cooling rate effect on blocking temperatures in stepwise thermal demagnetization.GEOPHYSICAL JOURNAL INTERNATIONAL,224(2),1117-1127. |
| MLA | Berndt, Thomas A.,et al."Experimental test of the cooling rate effect on blocking temperatures in stepwise thermal demagnetization".GEOPHYSICAL JOURNAL INTERNATIONAL 224.2(2021):1117-1127. |
入库方式： OAI收割
来源：地质与地球物理研究所
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