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Magnetostratigraphy of an early‐middle Miocene loess‐soil sequence in the western Loess Plateau of China
Author(s) -
Hao Qingzhen,
Guo Zhengtang
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl031162
Subject(s) - loess , geology , magnetostratigraphy , aeolian processes , paleontology , quaternary , loess plateau , sequence (biology) , stratigraphy , neogene , sequence stratigraphy , paleomagnetism , sedimentary depositional environment , structural basin , tectonics , biology , soil science , genetics
Stratigraphy and magnetic susceptibility of the Quaternary eolian deposits at different sites in China can be closely correlated, confirming their spatial coherence and temporal continuity. The extent to which these conclusions are true for the Miocene loess‐soil sequences remains to be addressed. Here, a 231.9‐m eolian section, QA‐III, is geomagnetically dated, yielding an age span of 21.4–11.4 Ma, with the portion older than 19.6 Ma being partially water‐reworked. The magnetozones, litholigic structure and magnetic susceptibility of the sequence are highly correlative with the QA‐I and QA‐II sections, 30 km west of QA‐III. These sequences demonstrate that the Miocene loess deposits are also spatially correlative in stratigraphy, present a near‐continuous sequence of paleoenvironment changes, and that magnetic susceptibility is a useful tool for stratigraphic correlation. The basal age of QA‐III confirms again the onset of Asian inland deserts and monsoon‐dominate climates by the early Miocene.