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Global-Scale Geomagnetic Reversals And Failed Reversals Reveal Man’s First Migrations Into China
NASA computer simulation using the model of Glatzmaier and Roberts.The tubes represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and vertical. The dense clusters of lines are within the Earth’s core
Ao et al. conduct high-resolution paleomagnetic measurements and mineralogical studies in paleolake sediments in the Nihewan Basin of northern China, which hosts two early hominid paleolithic sites, Feiliang and Lanpo. The authors identify a total of seven geomagnetic excursions between 1.6 million and 0.8 million years before present, providing the best record of changes in Earth’s magnetic field direction in the Northern Hemisphere around the Brunhes-Matuyama reversal, the last magnetic reversal that occurred 0.78 million years ago and hence one of the most important marker events in Earth’s history.
Seven of the nine excursions that the authors identify in the Nihewan Basin had not previously been well-identified in any other terrestrial archive in China. By tying the large excursions to well-defined global reversal events and the smaller ones to more local excursion events that had been previously reported, the authors derive a timescale of hominid migration. Their geomagnetic timescale indicates that the paleolithic sites Feiliang and Lanpo are around 1.2 million and 1.65 million years old, respectively, suggesting that early hominids migrated out of Africa and settled in northern China prior to 1.5 million years ago, long before the last major reversal took place on Earth.
Source:
Geochemistry Geophysics Geosystems, doi:10.1029/2012GC004095, 2012
Title:
“High-resolution record of geomagnetic excursions in the Matuyama chron constrains the ages of the Feiliang and Lanpo Paleolithic sites in the Nihewan Basin, North China;”
Authors:Hong Ao, Zhisheng An, Hui Zhao, Hongli Zhao, Xiaoke Qiang, Hong ChangState Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an, China;Mark J. DekkersDepartment of Earth Sciences, Utrecht University, Utrecht, The Netherlands;Qi Wei, Shuwen PeiInstitute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China;Guoqiao XiaoState Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China;Dacheng WuResearch Institute of Exploration and Development, Tarim Oilfield Company, Korla, China.
2012-08-15 15:41:24
Source: http://nanopatentsandinnovations.blogspot.com/2012/08/global-scale-geomagnetic-reversals-and.html
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