湖北庹家湾剖面释光测年与地层年代学及记录的55 ka BP气候变化
发布时间：2019-06-29 14:25
【摘要】：以湖北庹家湾剖面为研究对象,对其宏观组构、沉积学及理化性质(磁化率、粒度、色度、元素组成等)进行了测试,用OSL方法进行了测年断代。根据野外和室内实验数据,建立了汉江Ⅰ级阶地上黄土-古土壤的地层序列,并以OSL测年数据为依据进行了地层年代学研究,利用气候替代指标重建了汉江上游55 ka BP以来气候变化的轨迹。认为:汉江Ⅰ级阶地在55 ka BP前后形成,阶地形成后即刻开始接受连续的风尘堆积;其地层从下向上依次分为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);马兰黄土中记录了44.5~41.0 ka BP、37.5~34.0 ka BP、28.5~24.5 ka BP、23.0~21.0 ka BP四个暖湿气候阶段,其中28.5~24.5 ka BP和23.0~21.0 ka BP比较暖湿,形成了古土壤层L1-S2和L1-S1;庹家湾剖面记录的气候事件具有区域性特征,可与深海同位素曲线MIS-3进行良好比较,反映汉江地区MIS-3的后期暖湿程度较高;全新世大暖期(8.5~3.0 ka BP)在汉江上游地区并非一直表现为暖湿的特征,在5~6 ka BP出现短暂的相对凉湿的气候阶段。
[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，
本文编号：2507885
[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，
本文编号：2507885
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