New archaeomagnetic direction results from China and their constraints on palaeosecular variation of the geomagnetic field in Eastern Asia.

Bibliographic Details
Title: New archaeomagnetic direction results from China and their constraints on palaeosecular variation of the geomagnetic field in Eastern Asia.
Authors: Shuhui Cai, Lisa Tauxe, Chenglong Deng, Huafeng Qin, Yongxin Pan, Guiyun Jin, Xuexiang Chen, Wei Chen, Fei Xie, Rixiang Zhu
Source: Geophysical Journal International; Nov2016, Vol. 207 Issue 2, p1332-1342, 11p
Subject Terms: PALEOMAGNETISM, RADIOCARBON dating, DEMAGNETIZATION, HEMATITE
Geographic Terms: CHINA
Abstract: We carried out an archaeomagnetic directional study on 38 oriented samples (bricks and baked clays) collected from four archaeological locations at three provinces in China. The ages of our samples, spanning from ~3000 BCE to ~1300 CE, were constrained using a combination of archaeological context, radiocarbon dating and stratigraphic information. Rock magnetic results demonstrate that the main magnetic minerals of the studied samples are magnetite and/or hematite in single domain and superparamagnetic states. A total of 20 new reliable archaeodirectional data from 12 independent sites are obtained after thermal demagnetization experiments. These are the first set of archaeodirectional data in China produced since the 1990s. The published data are largely from the past 2 kyr and data from older time periods are rare. Our new data, especially those from period older than 3 ka, fill many gaps of the presently published dataset and will provide strong constraints on palaeosecular variation of the geomagnetic field in Eastern Asia and on the improvement of global models. Quite a few inflection points in the direction of the geomagnetic field are recorded in Eastern Asia over the past 10 kyr and some of them synchronize with the maximums or minimums of the palaeointensity. The palaeosecular variation rates are very low (based on present data distribution) before 2000 BCE and then start to increase and fluctuate afterward, which is generally consistent with the pattern of palaeointensity variations in this area. [ABSTRACT FROM AUTHOR]
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Database: Complementary Index
More Details
ISSN:0956540X
DOI:10.1093/gji/ggw351
Published in:Geophysical Journal International
Language:English