洞穴次生碳酸盐沉积稳定碳同位素研究

对国内外有关洞穴石笋稳定碳同位素值（13C,其计算公式为:13C = （Rsamp/Rstd - 1）*1000,Rsamp和Rstd分别为样品和标准的碳同位素比值）的研究成果进行了梳理和归纳总结,介绍了影响石笋13C值变化的因素（如植被（包括植被类型和生物量效应）、土壤过程、大气CO2、岩溶地下水水文（包括地下水的水动力条件、水-岩相互作用和先期碳酸盐沉积等）,同时介绍了一些模型研究中对影响石笋13C值的某些具体气候环境因素（如滴水快慢或时间间隔、通风强度、地下水流动路径等）进行的定量评估. 综合迄今为止洞穴石笋13C值的研究成果,指出洞穴内滴水的CO2去气作用可能是影响石笋13C值变化的关键机制,建议在今后的研究中对此给予高度关注.     

中扬子区晚石炭世碳酸盐岩的古岩溶成岩相

中扬子区晚石炭世碳酸盐岩与上覆早二叠世地层之间存在沉积间断／剥蚀面,并发育古风化壳．剥蚀面之下,碳酸盐岩古岩溶作用广泛发育,具有层间不平整剥蚀／溶解面、岩溶砾—角砾岩、溶解裂隙及与之连通的岩溶洞穴等古岩溶作用特征．将古岩溶作用叠加于先成碳酸盐岩地质体的一种特殊成岩环境的物质表现称为古岩溶成岩相．成岩环境可以暴露地表、近地表,成岩介质主要是大气淡水．区域碳酸盐岩古岩溶成岩相有特定的岩石学、粘土矿物、微量元素、氧碳同位素特征．垂向可以分带,横向可以对比,是一种对油气储集空间形成极为有利的特殊成岩相     

洞穴石笋氧同位素古气候重建应用

近年来,应用洞穴次生碳酸盐稳定氧、碳同位素进行古气候研究得到了迅速的发展,尤其是利用石笋中1δ8O与δ13C重建不同地区不同时间尺度下的古气候环境,为全球气候的变化提供了许多新的有意义的认识.然而,当前在利用石笋氧同位素进行古气候重建,特别是对1δ8O的解译过程中仍存在诸多不确定性,尤其是δ18O与温度、降水的联系不统一问题.该文从洞穴石笋δ18O与温度、降水的相关关系以及不同时间尺度下所指示的气候意义等角度对当前洞穴石笋气候学中氧同位素的应用进行了总结分析.     

洞穴石笋沉积纹层的形态组合及其滴水的水动力条件

石笋沉积纹层的组合、厚度、粒度和层面构造等,是恢复成笋滴水动态及相关古水文件的物质基础,根据众多大型石笋纵剖面的沉积纹 层的详细观测表明,石笋纹层组合形态,主要有：①平顶（柱）状对称昨纹层;②圆顶锥柱状对称叠复纹层;③尖顶锥状对称叠复纹层;④斜锥（柱）状不对称叠复纹层;⑤缓一平顶凹凸状叠复纹层;⑥其它复合叠加纹层,研究表明,石笋沉积纹层的形成,受洞穴滴水的水量、滴速或滴率、滴落、着落点的集中与分散、饱和度、水动力条件、PH值、温度和湿度等因素的影响,由于滴水的补给量、着落点的改变,导致在固－水界面的运动状态不同,所形成的滴石类型和石笋沉积纹层组合形态也各不相同。     

旅游洞穴次生CaCO3沉积景观风化剥蚀、变色机理及其改善与保护

洞穴次生碳酸钙CaCOa沉积物是旅游洞穴的主要观赏景观，其风化剥蚀、变色，直接影响到洞穴旅游业的可持续发展。本文对洞穴次生CaCOa沉积景观风化剥蚀、变色的多种原因和机理进行了阐述．并对景观变色的改善和景观保护提出了一些措施和建议。     

南京师范大学

<正>·我校汪永进教授团队获2013年度教育部高校科学研究成果(科学技术)自然科学一等奖地理科学学院汪永进教授团队"晚第四纪东亚季风演化历史与驱动机制"获奖项目以中国洞穴石笋为主要载体,研究不同时间尺度季风气候历史、突变过程及其与全球变化的关系,构建了相对完整的晚第四纪中国洞穴同位素气候地层学研究体系。获奖项目主要科学贡献有:发现亚洲夏季风强度变化在最后两个冰期/间冰期旋回具有显著的岁差旋回特征,完善了来自海洋沉积和中国黄土等研究对亚洲季风     

八万年来中国东部古气候与海平面变化的研究

通过对北京周口店和浙江临安瑞晶洞穴石笋的同位素古气候的研究，获的距今８—５万年间北京地区及距今５—１万年间杭州地区的古气候演化记录，并与我国东部同期的海平面变化曲线进行对比．     

洞穴石笋古温度研究进展及其可信度探讨

本文回顾了深海氧同位素曲线成功地反映了古温度变化的原因，分析了陆相环境古温度定量研究的困所在．洞穴钟乳石古温度研究经历了定性、半定量和定量三个发展阶段．最后对古温度定量研究中的三个影响因素（水的δ１８Ｏ，石笋生长速率及同位素分析精度）进行了探讨．     

淮北煤田奥陶系灰岩岩溶类型及陷落柱成因分析

对淮北煤田奥陶系灰岩不同时期岩溶洞穴发育条件及特征进行了分析，将其分为冲蚀型、潜蚀型、流入型及含水层型岩溶洞穴。根据层状沉积岩层的断裂力学机制及洞穴的再发育过程，提出了煤系地层陷落柱多期活动模式。     

海口,新海湾^210Pb法沉积速率的测定

本文叙述了~（２１０）Ｐｂ测年方法的基本原理和实验过程，并具体测定了海口湾和新海湾５个柱样的沉积速率，为０．３８～１．０４ｃｍ／ａ。     

贵州一石笋TIMS--铀系定年及其古气候研究

通过对贵州七星洞ZFQX1石笋进行TIMS--铀系定年及其生长率分析,获得了距今43.02-1 2.65 ka的古气候信息.该石笋反映了此阶段贵州地区经历了暖湿--冷干--暖湿的气候演变趋势,这与全球古气候变化波动基本一致,同时也具有地区性的气候特点.     

末次盛冰期南京降水记录中ENSO的演化

基于南京葫芦洞一支石笋TIMS-U系测年和纹层计数的交叉定年。获得丁末次盛冰期在24170～21222aBP时段石笋年纹层厚度的时间序列,主要反映了夏季风降水变率．小波分析揭示末次盛冰期连续3ka夏季风降水记录中厄尔尼诺一南方涛动（ENSO）周期和强度随时间的演化特征,该记录表明ENSO在末次盛冰期并非一直存在,有着高发期和平缓期。其爆发的频率和强度逐渐减弱。支持ENSO演化的“冰期阻尼效应”假说．     

A continuous 3000—year precipitation record of ENSO variability during LGM from a stalagmite in Nanjing

A glacial stalagmite chronology from Nanjing has been established by the TIMS-U series dating and annual band counting methods. The annually layering sequence spanning the 3000-year period from 18179 to 14900 calendar years before the present (aBP) was analyzed for evidence of East Asian summer monsoon precipitation variability during the Last Glacial Maximum (LGM). Power spectral analysis of the sequence shows a distinct interannual (2—7 years) band of enhanced variability suggestive of El Ni駉-Southern Oscillation (ENSO) teleconnections into East China during the LGM when climatic boundary conditions were different from those of today. The lower frequency bands (4—7 years) variability becomes weaker from 18179 to 14900 aBP, sup-porting the precession forcing model. The reappearance of the ENSO band in the coldest climatic boundary conditions during the Heinrich Event 1, however, suggests the stimula-tion of the enhanced East Asia winter monsoon to the El Ni駉 events.     

A continuous 200-ka palaeoclimatic record from stalagmite in Tangshan Cave, Nanjing

An oxygen isotope temperature record from 381 to 166 kaB. P. (²³⁰Th/²³⁴U dating and tuned ages) has been obtained by combining data on the isotopic composition of calcites with that of fluid inclusions trapped in a stalagmite from a limestone cave in which a fossil cranium deposited. Several laminae in microsequence of the stalagmite represent climatic events or shifts. The Nanjing man fossil was older than 381 kaB. P.     

贵州荔波42.0kaB.P.~65.0kaB.P.气候变化的石笋记录

对贵州荔波董哥洞D42石笋进行TIMS-U测年和碳、氧同位素分析,建立末次冰期42．0ka B．P．～65．0ka B．P．的古气候变化时间序列。研究结果表明,荔波地区在65．0ka B．P．～42．0ka B．P．石笋记录的冷暖事件所反映出的季风气候变化,大致可分为3个气候阶段;65．0ka B．P．～60．6ka B．P．相当于海洋氧同位素MIS4晚期,反映本阶段东亚冬季风强盛,气温降低,表现为干旱寒冷的气候环境;60．6ka B．P．～48．4ka B．P．相当于海洋氧同位素MIS3早期,反映东亚夏季风相对增强,气温升高,有效降水相对较少,表现为温暖半干旱的气候环境;48．4ka B．P．～42．0ka B．P．相当于海洋氧同位素MIS3中期,显示东亚夏季风由强变弱,东亚冬季风相对增强,表现为干旱冷凉的气候环境。石笋记录揭示的2次寒冷事件在各类沉积物中均有记录,反映为全球变化的气候事件,相当于北大西洋沉积物中的Heinrich5和Heinrich 6冷事件,可以进行全球对比,显示荔波地区与北极地区存在着古气候的遥相关。     

A high-resolution stalagmite O-C isotope record from Nanjing and its rapid response to climatic events

Here we discussed rapid response of the cave temperature and vegetation to the four Dansgaard-Oeschger cold and warm cycles during 50-40 kaBP based on results of oxygen and carbon stable isotopic compositions from a stalagmite in Tangshan, Nanjing. It is found that the amount of C₃ vegetation relative to C₄-type declines during the D-O warm events, indicating the decrease of the effective meteoric precipitation. Compared with O-isotope records of the Greenland ice core, the stalagmite record displays a very similar pattern to Greenland ice core record over the decade-century time scale, suggesting that the changes of the East Asian monsoon climate are in accordance with the high-latitude polar climate in the short-term time scale. The age of the ice-rafted H5 event in the stalagmite record, however, preceded that of Greenland ice cores by 2 ka. This out of phase between the remote areas cannot be yet proven because the two time scales were determined from different dating methods.     

Precise dating of Dansgaard-Oeschger climate oscillations in western Europe from stalagmite data

The signature of Dansgaard-Oeschger events--millennial-scale abrupt climate oscillations during the last glacial period--is well established in ice cores and marine records. But the effects of such events in continental settings are not as clear, and their absolute chronology is uncertain beyond the limit of (14)C dating and annual layer counting for marine records and ice cores, respectively. Here we present carbon and oxygen isotope records from a stalagmite collected in southwest France which have been precisely dated using 234U/230Th ratios. We find rapid climate oscillations coincident with the established Dansgaard-Oeschger events between 83,000 and 32,000 years ago in both isotope records. The oxygen isotope signature is similar to a record from Soreq cave, Israel, and deep-sea records, indicating the large spatial scale of the climate oscillations. The signal in the carbon isotopes gives evidence of drastic and rapid vegetation changes in western Europe, an important site in human cultural evolution. We also find evidence for a long phase of extremely cold climate in southwest France between 61.2 +/- 0.6 and 67.4 +/- 0.9 kyr ago.     

The thermal history of the miarolitic granite at Xincun, Fujian Province, China

The thermal history of the late Mesozoic miarolitic granite has been studied based on zircon U-Pb dating, whole rock Rb-Sr dating and K-Ar dating of muscovite, biotite and K-feldspar from the same rock sample. From the beginning of zircon crystallization to the closure of K-Ar system of biotite, the granite body had a slow cooling rate (11.0℃/Ma) and an ascending rate (0.07 mm/a). From the end of this stage to the closure of K-Ar system of K-feldspar, the granite body increased its cooling rate (45℃/Ma) and ascending rate (0.36 mm/a). The thermal history of the Xincun granite with a slow cooling rate at the early stage and a fast cooling rate at the late stage may have been related to the fact that the Fujian coastal area had very high geothermal gradient in the late Mesozoic and evident decrease in geothermal gradient in the early Cenozoic.     

Environmental changes recorded in lake sediments for 13 000-1 000 a B. P. in Beijing area

The detailed¹⁴c dating, palynological, carbon isotope and magnetic susceptibility analyses of a paleo-swamp record obtained near Beijing show that the succession of climate events in Beljing area is broadly consistent with the climatic behavior in the North Atlantic region during the period from 13 000 to 10 000 a B. P., but with evident local characteristics. A relatively warm and wet episode (11 400-10 950 a B.P.) was intercalated between two dry-cold episodes (11 600-11 400 and 10 950-10 450 a B. P.).     

下辽河平原全新世孢粉组合与古气候演化研究

通过对下辽河滨海平原区田家镇LT钻孔样品不同种属孢粉所占的数量百分比进行分析,将柱状样划分了7个孢粉组合带.根据各孢粉带的不同孢粉组合特征,利用对应分析方法以及在14C测年技术的支持下,重建了该地区全新世以来以温湿—暖湿—湿热—冷干—暖湿—凉干为特征的古气候演化序列.