末次间冰期全球变化区域响应的粒度旋回———萨拉乌苏河流域米浪沟湾剖面记录

位于毛乌素沙漠东南的萨拉乌苏河流域米浪沟湾剖面末次间冰期层系记录了8．5个古风成砂与河湖相和古土壤构成的显著的粗细韵律交替变化粒度旋回．通过对不同沉积相粒度的一般分布特征尤其是粒度参数-Mz、σ、Sk、Kg和SC／D值以及该地生物化石指示的古环境综合分析，认为所述粒度旋回主要是东亚冬夏古代季风交替影响下的气候旋回波动所致。     

泥河湾盆地末次间冰期气候变化的氧碳同位素记录

黄土－古土壤序列的研究表明，我国东部地区第四纪气候演变的总规律是干冷与湿暖的交替，但是，气候的变化是一个复杂的过程，在不同的时间和地点，气候的干，湿和冷，暖变化可能会出现不同的组合。根据泥河湾盆地晚更新世湖泊沉积物中所含碳酸盐的氧碳同位素研究，认为在末次间冰期（据今１３～７万年）。该区气候以干暖与湿冷的交替主要特征，这一发现将有助于加深对我国东部第四纪气候变化规律的认识。     

下一次冰河纪何时开始?

俗话说“离去的又将回来”,没有什么能比用这句话来形容冰河纪更为合适的了。在过去的100万年中,冰盖的展缩和洋面的涨落随着地球轨道旋转的节拍周而复始来回更替了十个纪元。 事实上,在整个那段时间里,寒冷期占了绝对主导的地位,所以地球物理学家把被称为全新世的这样的温暖时期看作是一个奇特现     

Paleoceanographic records in the sedimentary cores from the middle Okinawa Trough

Two gravity piston cores (Cores 155 and 180) involved in this study were collected from the middle Okinawa Trough. Stratigraphy of the two cores was divided and classified based on the features of planktonic foraminifera oxygen isotope changes together with depositional sequence,millennium-scale climatic event comparison, carbonate cycles and AMS^14C dating. Some paleoclimatic information contained in sediments of these cores was extracted to discuss the paleoclimatic change rules and the short-time scale events presented in interglacial period. Analysis on the variation of oxygen isotope values in stage two shows that the middle part of the Okinawa Trough may have been affected by fresh water from the Yellow River and the Yangtze River during the Last Glacial Maximum (LGM). The oxygen isotope value oscillating ranges of the cores have verified that the marginal sea has an amplifying effect on climate changes.The δ^13C of benthic foraminifera Uvigerina was lighter in the glacial period than that in the interglacial period, which indicates that the Paleo-Kuroshio‘s main stream moved eastward and its influence area decreased. According to the temperature difference during the “YD” period existing in Core 180 and other data, we can reach the conclusion that the climatic changes in the middle Okinawa Trough area were controlled by global climatic changes, but some regional factors had also considerable influence on the climatechanges. Some results in this paper support Fairbanks‘s point that the “YD” event was a brief stagnation of sea level rising during the global warming up procession. Moreover,the falling of sea level in the glacial period weakened the exchange between the bottom water of the Okinawa Trough and the deep water of the northwestern Pacific Ocean and resulted in low oxygen state of bottom water in this area.These procedures are the reasons for carbonate cycle in the Okinawa Trough area being consistent with the “Atlantic type”carbonate cycle.     

The possible pivotal role of the eastward dust transport from Central Asia in the global temperature decrease

It is generally considered that the occurrence of glacial-interglacial gyrations can be explained with the Milankovitch theory. However, the solutions of some problems in the theory are currently not derived yet. After researching the eastward dust transport from Central Asia, we have found that there is a positive feedback mechanism between the eastward dust transport and the global temperature decrease. This magnifies the effect of solar radiation change in the high-latitude Hemisphere, and results in area of the Northern the occurrence of the global glacial epoch. The positive feedback mechanism starts with the reduction of solar radiation in the high-latitude area of the Northern Hemisphere. Subsequently, the global temperature decreases and global glacial epoch occurs, in which the pivotal fac- tor is the eastward dust transport from Central Asia. With the theory of the positive feedback mechanism, some problems in the Milankovitch theory can be solved well.     

青藏高原东部RM孔碳酸盐氧同位素揭示的末次间冰期气候特征

最近,格陵兰冰芯研究揭示的气候不稳定性被作为过去全球变化研究的重大进展。GRIP氧同位素研究首先提出,相当于深海氧同位素地层5e亚段的暖期气候(Eemian)存在着两次明显的冷事件,这一发现后来被欧洲湖泊记录所证实。但是GISP2未发现Eemian暖期气候有明显波动,Kelgwin等对大西洋沉积记录的研究也得出与此相似的结论。因此,一些研究者对Eemian暖期内部存在气候突变的观点表示怀疑。最近作者对青藏高原东部RM孔湖泊记录研究结果,发现末次间冰期5e亚段存在两次冷事件,支持了GRIP研究者的观点,同时证实了此种气候不稳定性也存在于中国的青藏高原这一事实。     

末次间冰期黄土高原粉尘事件及其与北大西洋寒冷事件的对比

通过对我国黄土高原 2个末次间冰期剖面的石英粒度分析 ,发现在这一时段由粗颗粒含量增加所指示的重要粉尘堆积事件有九次 :DE1( 70～ 71ka)、DE2 ( 74 5～ 75ka)、DE3( 81 3～ 83ka)、DE4 ( 90～ 91ka)、DE5( 10 1～ 10 2ka)、DE6( 10 6～ 10 6 7ka)、DE7( 110ka)、DE8( 113 5～ 115ka)、DE9( 119～ 12 1 6ka)并且和北大西洋V2 9_191孔有孔虫气候记录在距今 110～ 70ka时段中具有极为相似的变化 ,这表明 ,在末次间冰期中存在东亚季风气候通过西风带以及相关气压系统与极地、北大西洋气候系统的遥相关 .进一步佐证了东亚冬季风气候通过西伯利亚高压与极地、北大西洋冷空气相联系的观点     

末次间冰期5e亚阶段夏季风快速变化的环境岩石磁学研究

末次间冰期古土壤和黄土百年－千年尺度系统的环境岩石磁学研究表明,亚洲夏季风在相当深海氧同位素５ｅ亚阶段曾有过急剧的波动,表现为３峰２谷,峰谷延续时间约为１￣２ｋａ,其中中央年龄在约１２０．５ｋａ的谷４最醒目,指示夏季风的减弱几乎达到冰期的水平,反映夏季风在末次间冰期中呈不稳定性变化。     

论鄂西南岩溶洞穴发育与第四纪冰期和间冰期的关系

本文简述了鄂西南利川市东北部岩溶洞穴体系上、中、下层状溶洞发育状况,论述了其发育过程与第四纪冰期和间冰期的关系,在间冰期时形成水平溶洞,在冰期时形成垂直溶洞,二者互相贯通,形成了岩溶洞穴体系。     

Changes in sea surface temperature in western South China Sea over the past 450 ka

Sea surface temperature over the past 450 ka was obtained by the unsaturation of molecular fossil-long chain alkenone with a resolution of about 1 ka from the western South China Sea. This is the longest temperature profile in the South China Sea at such high resolution. The U37^κ-SST results revealed similar glacial-interglacial cycles as the δ^18O profile of planktonic foraminifera, with SST variability of 23-25.5℃ for glacial and 25-28℃ for interglacial periods. The highest SST （28.4℃） was recorded at MIS5.5 and lowest SST （22.6℃） during MIS2. The SST record preceded the planktonic foraminiferal δ^18O on five glacial-interglacial transitions. Comparison of temperature records from the Southern and Northern Hemispheres indicated a more Southern Hemisphere-like pattern for the temperature variation in the SCS. Strong precession and semiprecession signals in the spectra of our SST record manifest the tropical phenomena.