风水交汇区沉积环境重建及物源示踪研究-以黄河河套平原段为例
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更新:2024-04-10 22:12:56 浏览:835次
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摘要
Investigating fluvial-aeolian interactions is important for understanding Earth surface processes in arid regions.
In this study, we conducted detailed grain size, geochemical, and heavy-mineral analyses of the 21.25-m-long
HDZ core to determine the provenance of Holocene aeolian deposits in Inner Mongolia and their relationships
with the Yellow River and surrounding desert areas. Significant differences in grain-size parameters and con-
centration of geochemical elements with stratigraphic depth were highlighted. Compositional data and heavy-
mineral assemblages indicate that aeolian sediments blown into the Yellow River channel were largely
derived from the Ulan Buh Desert or Kubq Desert and supplied by the Ten Tributaries during the rainy season.
Chemical indices depicta particularly low weathering intensity during the late Holocene between 3.3 and 1.0 ka,
when the dry-cool climate led to desert expansion in the Inner Mongolia region of the Yellow River. Starting
from ~2000 BP during the Han Dinasty, large-scale immigration, extensive agricultural activities, and intensified
animal grazing compromised the stability of surface soil, leading to desertification and enhanced aeolian-sand
transport across the Inner Mongolia region. Our research helps understand the extreme sensitivity of vulner-
able dry environments to climate change at different time scales and provide a reference for provenance iden-
tificationin a region of extensive fluvial-aeolian interactions.
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