Stratigraphic architecture of the Neoproterozoic glacial rocks in the “Xiang-Qian-Gui” region of the central Yangtze Block, South China

Recently ,theinterestinglowlatitudeandlowaltitudeSnowballEarthhypothesis[1,2 ] iswidelyreco gnized ,and greatlystimulatingthestudyoftheNeoproterozoicglaciations ,whichmaybecloselyre latedtothewell knownEarlyCambrianbio radiationevent.By 1980 ,theNeoproterozoicglaciationinSouthChinaisbelievedtobedividedintotwoglaciationsandoneinterglaciation[3～ 5] ,namely ,theearlyChang’anGlaciation ,lateNantuoGlaciationandFu luInterglaciation .However ,thereweredifferentwaysofcorrelation ,themostobvious…     

青藏高原第四纪冰期序列及其意义

普兰丁喀里山口和理塘海子山地区第四纪冰川遗迹的研究进一步证实,近２Ｍａ来,青藏高原经历过５次冰期和４次间冰期。青藏高原第四纪冰期序列的研究,对于完善大陆第四纪冰期序列、研究全球变化、认识中国东部第四纪冰川作用都具有重要意义。     

硫酸铅产品质量影响因素的研究

介绍了悬浮法合成硫酸铅的新工艺，并对影响产品质量的各种因素进行了探讨，该法采用冰乙酸作催化剂，在水介质中加入氧化铅，再滴加一定量的浓硫酸来合成硫酸铅，实验最佳条件为：硫酸浓度为94．5％，催化剂用量为0．07L／Kg，加酸速度为1－1．2g/min，氧化铅颗粒粒度为180－200目，PH值为4－5，干燥蒸汽压力为0．45Pa。与工艺相比较，本工艺具有生产周期短，洗涤废水后处理量少，安全操作性好，产品成本低等特点。     

Mineral deformation and subglacial processes on ice-bedrock interface of Hailuogou Glacier

Hailuogou Glacier is located in a warm and humid maritime environment. It is large and moves very fast. The bottom of the glacier slides intensively and the temperature at the bottom approaches the pressure melting point. Therefore, there are abundant melting water and debris which act as effective ＂grinding tools＂ for glacial abrasion. Polarizing microscope is used to observe the mineral deformation characteristics on the ice-bedrock interface. It is found that feldspar, quartz, hornblende and biotite are exposed to deformation, fracture and chemical alteration to various extents. Bending deformation is common for biotite, due to their lattice characteristics, and the bending orientations are mostly the same as the glacier flow. Bending deformation also occurs in a few hornblendes. High-angle tension fracture and low-angle shear fracture are common for quartz and feldspar, some of them are totally crushed （mylonizations） due to their rigidity. Thus, all the abrasion, quarrying, subglacial water action and subglacial dissolution processes at the bottom of the glacier are verified at the micro-scale level. Mineral deformation and fracture are the basic subglacial erosion mechanisms. The abrasion thickness is 30-90 μm for each time and the average is 50 μm. Most of the debris are silt produced by glacial abrasion. The extent of mineral deformation and fracture decreases drastically downwards beneath the bedrock surface. The estimated erosion rate is about 2.2-11.4 mm/a, which is similar to that of other maritime alpine glaciers, smaller than that of large-scale piedmont glaciers in Alaska （10-30 mm/a）, and larger than that of continental glaciers （0.1-1.0 mm/a）. The type and size of a glacier are the main factors that influence its erosion rate.     

帕米尔高原花岗岩漂砾风化穴初步探究

通过对东帕米尔高原一冰碛平台上花岗岩漂砾风化穴的仔细观察,根据发生部位和形态特征对风化穴进行分类,并结合当地地形、气温、降水等自然条件对风化穴的成因进行分析,初步认为本区花岗岩漂砾风化穴的主要类型为边墙形、蜂巢型、底穴型、沟槽型,是温差风化（含寒冻风化）、盐风化、风蚀和时间（倒数第二次冰期以来）因素综合作用的结果,其中谷风侵蚀在边墙型风化穴形成过程中起主导作用．     

秭归庙河的第四纪冰川遗迹

描述了秭归庙河一带的冰斗、漂砾、冰川谷及冰水阶地等冰川遗迹,该古冰川的发现有利证实中纬度地区中低山第四纪时冰川运动的存在．为了探讨该地第四纪经冰川作用,从影响冰川形成的机制（降水、温度和雪线高度）出发,通过与庐山地区的气候特征对比,来进一步阐明秭归地区第四纪冰川作用．基于庙河阶地中钙结岩中δ^18O的分析,恢复了该地第四纪冰期时的古气温和降雨量,第四纪冰期时温度和降水分别为一3．1～＋3．2℃和776～1155mm,这种气候背景条件有利于低山冰川作用的形成,总结出庙河第四纪时的冰期．     

青藏高原的抬升和夷平过程对气候与环境的影响

系统地讨论了高原隆起前的早第三纪至现代青藏高原的７次抬升过程对气候和环境的影响，应用气象学理论分析了当时气候形成的原因。主要结论：（１）高原隆起前的干热气候是由于隆起前全球地势平坦，致使大气热机效率很低之故；（２）渐新世初高原的水平尺度达到了斜压大气地转适应的临界尺度，大气环流从南北两极“两涡对峙”突变成地球三极的“三涡鼎立”，气候发生突变；（３）分析了２．５Ｍａ时高原抬升到２０００ｍ这一重要临界高度后大气环流的一系列相应变化；（４）计算、比较了最大冰期地气系统能量平衡与现代的差异，并由此分析了当时的气候状况     

Turbidite deposition in the southern South China Sea during the last glacial: Evidence from grain-size and major elements records

High-resolution grain size and major element geochemical measurements were performed on the marine sediments of Core MD05-2895 to help understand the formation of turbidite sequences. Grain-size results show that these turbidite sediments contain more coarse sediment grains than normal marls. The coarse sediment grains are mostly derived from relict sediments on the Sunda Shelf. Relict sediments are composed mainly of quartz, feldspar, tephra and a few titaniferous or ferruginous heavy minerals. Corresponding to the concentration of these minerals, increases in Si/Al, K/Al, Ti/Al and Fe/Al ratios are observed in the turbidite layers. As all the observed turbidite sequences were deposited during the last glacial, the occurrence of these turbidity events is implied to be closely related to instabilities in sea-level-induced sediment supply. We suggest that deposition of sediment particles from a single turbidity current is usually controlled by a counterbalance between gravity and buoyancy, with the interaction of individual grains being of minor importance.     

三门峡王官与武威沙沟黄土记录中的末次间冰期向末次冰期转换期的暖性回返事件

河南三门峡王官剖面与甘肃武威沙沟剖面捕捉到了末次间冰期向末次冰期转换时期发生于72 ka前后持续时间约为2 ka的一暖性回返事件,两剖面的冬、夏季风替代指标对该暖性回返事件的反应在时间上大致同步(其时间段约为71～73 ka,在71.4～72.1 ka前后该暖性回返事件最强盛),暗示该暖性回返事件在东亚季风区可能是一普遍存在的气候突变事件.鉴于该暖性回返事件在全球其他地区的海洋、陆地、冰芯记录中也有较普遍的反映,我们认为该事件很可能是一次发生于气候转型期的全球普遍存在的暖性突变事件.     

辽南地区末次冰期以来的环境变化

本文通过对大连七顶山黄土剖面的光释光(OSL)年代、磁化率、地球化学元素、粒度特征等数据,综合分析辽南地区末次冰期以来的环境变化过程,研究结果显示:相当于黄土高原马兰黄土的堆积形成时代为距今125ka。在末次冰期早期(MIS4-5d),86-113ka,沉积物质量磁化率介于6.97-24.14×10-8m3kg-1之间,平均值为14.699×10-8m3kg-1;颗粒粒径较细(3.89-5.22准);硅铝率平均值6.756;风化淋溶系数0.4-0.73之间;退碱系数均值0.333;镁铝比均值22.901。与末次冰期晚期相比,质量磁化率值较高,化学元素各项指标值较低,明了该阶段辽南整体气候环境较为干冷,但并未达到末次冰期晚期程度。而在末次冰盛期时(22-31ka,MIS2),磁化率平均值为6.974×10-8m3kg-1,明显低于末次冰期早期,粒度均值处于3.47准-4.77准之间,主要以颗粒较粗的细砂、粗粉砂为主,粒度明显变粗,硅铝率平均为6.998;风化淋溶系数均值为0.829,退碱系数值0.66,镁铝比值均值28.725,各参数比较一致地表明该阶段研究区整体处于干冷的气候环境之下,堆积作用较活跃。而在末次冰期中期(MIS3)时,OSL年代31-86ka,该区气候条件以温暖湿润为主,黄土遭到侵蚀。