【摘要】：以湖北庹家灣剖面為研究對象,對其宏觀組構(gòu)、沉積學(xué)及理化性質(zhì)(磁化率、粒度、色度、元素組成等)進(jìn)行了測試,用OSL方法進(jìn)行了測年斷代。根據(jù)野外和室內(nèi)實(shí)驗(yàn)數(shù)據(jù),建立了漢江Ⅰ級階地上黃土-古土壤的地層序列,并以O(shè)SL測年數(shù)據(jù)為依據(jù)進(jìn)行了地層年代學(xué)研究,利用氣候替代指標(biāo)重建了漢江上游55 ka BP以來氣候變化的軌跡。認(rèn)為:漢江Ⅰ級階地在55 ka BP前后形成,階地形成后即刻開始接受連續(xù)的風(fēng)塵堆積;其地層從下向上依次分為L1-L3(55.0~28.5 ka BP)→L1-S2(28.5~24.5 ka BP)→L1-L2(24.5~23.0 ka BP)→L1-S1(23.0~21.0 ka BP)→L1-L1(21.0~11.5 ka BP)→Lt(11.5~8.5 ka BP)→S0(8.5~3.0 ka BP)→L0(3.0~0 ka BP);馬蘭黃土中記錄了44.5~41.0 ka BP、37.5~34.0 ka BP、28.5~24.5 ka BP、23.0~21.0 ka BP四個暖濕氣候階段,其中28.5~24.5 ka BP和23.0~21.0 ka BP比較暖濕,形成了古土壤層L1-S2和L1-S1;庹家灣剖面記錄的氣候事件具有區(qū)域性特征,可與深海同位素曲線MIS-3進(jìn)行良好比較,反映漢江地區(qū)MIS-3的后期暖濕程度較高;全新世大暖期(8.5~3.0 ka BP)在漢江上游地區(qū)并非一直表現(xiàn)為暖濕的特征,在5~6 ka BP出現(xiàn)短暫的相對涼濕的氣候階段。
[Abstract]:Taking Tuojiawan section of Hubei Province as the research object, its macroscopic fabric, sedimentology and physical and chemical properties (magnetic susceptibility, particle size, chromaticity, element composition, etc.) were tested, and dating were carried out by OSL method. Based on the field and laboratory experimental data, the strata sequence of loess and paleosol on the first terrace of Hanjiang River is established, and the stratigraphy is studied on the basis of OSL dating data, and the track of climate change since 55 ka BP in the upper reaches of Hanjiang River is reconstructed by using climate substitution index. It is considered that the stage I terraces of Hanjiang River were formed before and after 55 ka BP, and began to receive continuous wind and dust accumulation immediately after the formation of terraces. The strata are divided into L1-L3 (55.0 鈮，

本文編號：2507885