Magnetic fabric from red clay sediments in the Chinese Loess Plateau.
Well-distributed eolian red clay in a wide area of northern China is believed to imply the onset of an ancient East Asian monsoon system since Late Miocene. Two continuous red clay sequences spanning the time interval 7-2.6 Ma and 11-2.6 Ma in the Chinese Loess Plateau was investigated to determine the magnetic orientation and grain alignment in the primary fabric of eolian sediments. The north-westerly orientation of the AMS of the eolian red clay sequences parallels the material transportation direction, which differs from the model that suggests that airborne dust from overlying loess-paleosol sequences were transported by the East Asian winter monsoon and fixed by the East Asian summer monsoon. Our results further reveal that present-day climate and air circulation patterns differ from those of the pre-Quaternary, and may provide evidence of a prevailing wind during deposition of the red clay.
1] Institute of Cenozoic Geology and Environment, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, X'ian 710069, China [2] State Key laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, X'ian 710075, China.
Hujun
H
Gong
1] Institute of Cenozoic Geology and Environment, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, X'ian 710069, China [2] State Key laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, X'ian 710075, China [3] Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China.
Rui
R
Zhang
1] Institute of Cenozoic Geology and Environment, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, X'ian 710069, China [2] State Key laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, X'ian 710075, China [3] Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China.
Leping
L
Yue
1] Institute of Cenozoic Geology and Environment, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, X'ian 710069, China [2] State Key laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, X'ian 710075, China.
Yunxiang
Y
Zhang
1] Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China [2] Institute of Cenozoic Geology and Environment, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, X'ian 710069, China.
Jianxing
J
Li