Chronology of the Baxie Loess Profile and the History of Monsoon Climates in China Between 17,000 and 6000 Years BP

Datos Bibliográficos

ID9243228
AutoresWeijian Zhou (0000-0001-9641-5734), Zhisheng An, Benhai Lin, Jule Xiao, Jinzhao Zhang, Jun Xie (0000-0002-4359-1045), Mingfu Zhou, S C Porter, M J Head, D J Donahue
Año1992
Volumen34
Número3
Páginas818-825
Fecha de publicación1992-01-01
Peer ReviewedSí
Open AccessSí
TipoARTICLE
RevistaRadiocarbon (JOURNAL)
Identificadores de la revistaISSN: 0033-8222 • E-ISSN: 1945-5755
EditorialCambridge University Press (CUP) (PUBLISHER)
DOI10.1017/s0033822200064122
OpenAlexW2504028326
IdiomaEN
Citas recibidas15
Referencias citadas13

The valley of the Baxie River, situated in the western region of the Loess Plateau in central China, contains a loess profile 15 m thick, which can be considered representative of loess-paleosol sequences formed over the last 17 ka. Both thermoluminescence (TL) determinations on fine-grained sediment (4–11 μm) and 14 C determinations on various organic fractions of paleosols from the profile have provided an extremely useful chronological framework for these sequences. These sequences indicate a weakened summer monsoon during the last glacial maximum followed by a strengthening of the summer monsoon, beginning ca. 13 ka cal bp. An abrupt change to a weakened summer monsoon regime lasted from ca. 10.9 to 10.2 ka cal bp. The Asian summer monsoon circulation, recording the Holocene optimum, then increased and lasted from ca. 10.2 to 6 ka cal bp. The organic component of samples taken down the profile has δ 13 C values ranging from −21 to −24‰ with respect to the PDB standard. The more positive δ 13 C values suggest that the proportion of C 4 -type plants in river valleys of the Loess Plateau increased as Asian summer monsoon influence weakened, and C 3 -type vegetation increased as the summer monsoon influence strengthened. Magnetic susceptibility and organic content were low during loess deposition, also reflecting weakening of summer monsoon. Two 14 C determinations on the humin fraction of the organic component near the top of the lower paleosol and the base of the upper paleosol complex gave ages of 10.2 and 10.9 ka cal BP, respectively. These ages mark the beginning and termination of a brief event involving increased dust influx under weakened summer monsoon conditions

Chronology · Climatology · East Asian Monsoon · Geography · Geomorphology · Glacial period · Holocene · Loess · Monsoon · Paleosol · Physical geography · Radiocarbon dating · Sediment · Archaeology and ancient environmental studies · Geology and Paleoclimatology Research · Pleistocene-Era Hominins and Archaeology · Geology · Paleontology