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在青藏高原南部雅鲁藏布江中游的河流阶地上堆积着1~3m厚的风成黄土,颗粒较粗,发育有不同程度的垂直节理。经光释光测试年代,发现它们形成于12ka BP前后,是沉积速率达到0.47~1.49m·ka-1的快速黄土堆积。河流两岸高山上岩体经风化产生的碎屑物质汇集在河流谷地,在新仙女木(Younger Dryas,YD)时期干冷的气候条件下,经强劲的地表风搬运至山前平坦的河流阶地上,形成黄土堆积。这些黄土沉积揭示出YD时期青藏高原南部气候干冷,风沙活动强。
Aeolian loess, 1 ~ 3m thick, is accumulated on the river terraces in the middle reaches of the Brahmaputra in the south of the Qinghai-Tibet Plateau with coarse grains and varying degrees of vertical joints. After the light-emitting test, it was found that they formed rapidly in the vicinity of 12ka BP, which was a rapid loess deposition with a deposition rate of 0.47-1.49 m · ka -1. Crude debris from alpine massif on both sides of the river converges in river valleys and is transported by strong surface winds to flat terraces in riverbanks under dry and cold weather in the period of Younger Dryas (YD) Formation of loess accumulation. These loess deposits reveal that the climate in the southern Tibetan Plateau during the YD period is dry and the wind and sand activities are strong.