末次间冰期以来源自中亚的粉尘记录的对比

A Comparison of the Records of Dust Originated from Central Asia since the Last Interglacial

中亚干旱区是全球重要的粉尘源区, 粉尘经过不同的大气环流系统的搬运和具体的沉积条件,在其传输路径上沉积于不同的介质中, 如冰芯、黄土、湖泊和深海. 在前人所做工作的基础上, 以古里雅冰芯、宝鸡黄土剖面、琵琶湖风尘沉积、北太平洋风尘沉积和格陵兰冰芯等记录进行对比, 初步讨论近130 ka BP以来上述记录所反映的中亚粉尘的产生、搬运和沉积. 这些记录既表现出一致性, 也存在某些差异, 显示了搬运过程、沉积过程以及区域性因素对粉尘记录的影响.

Central Asia is an important dust source in the Northern Hemisphere. Dust from this area is transported by different atmospheric circulations, deposited along different routes, and recorded in the Guliya and the GISP2 ice cores, the Baoji loess section, the lacustrine sediment from Lake Biwa, the North Pacific deep-sea sediment. The REE, mineralogy, and isotope composition also prove that the dust in the North Pacific and Greenland ice sheet comes from the Central Asia, especially the Taklamakan Desert. Concentration, particle size, and accumulation rate are chosen for proxies of those atmospheric dust records. In this paper, the dust records of the sediments since the Last Interglacial are compared and discussed. It is found that some records are consistent and some records are different, though the comparison is limited by timescale and resolution. All the records show a low dust concentration during the MIS 5 and MIS 3, and a high dust concentration during the last glacial. Though a change in source areas may influence all the records, the transport, sedimentation, and regional or local situations would affect the dust records, such as a low concentration in the Guliya ice core during the Last Glacial Maximum and a high dust concentration in North Pacific eolian sediments in the Middle Holocene. So, it seems necessary that all these records need to be integrally considered in order to get a more comprehensive knowledge on the evolution of Central Asia dust and atmospheric circulation. Due to its high elevation and desertification process, the Tibetan Plateau might also be a very important dust source area in the Northern Hemisphere.