Characteristics of strontium isotopes and their implications in the Qixing Cave of Guizhou,China

The strontium isotopic compositions (87Sr/86Sr) of samples including soils, bedrock, soil waters, drip waters and their corresponding speleothems in the Qixing Cave (QXC), Guizhou Province, China, were systemically measured and analyzed. The results indicate that there are significant Sr isotopic differences among samples. The mean 87Sr/86Sr ratios in drip water for the samples 1#, 4# and 9# were 0.709568, 0.709139 and 0.708761, respectively, which possibly result from different flow paths, residence times, and other hydrogeological processes in the unsaturated zone overlying QXC. Meanwhile, levels of 40.8%, 57.6% and 72.4% of Sr in drip waters for 1#, 4# and 9#, respectively, were derived from bedrock dissolution, which was calculated by the mixture model of the two end-members (soil and bedrock). There is, however, no positive correlation between the relative proportion from bedrock dissolution (δ13C value is 1.8‰) and drip water δ13CDIC values. The mean drip water δ13CDIC value in 1# is the heaviest (–4.5‰) with the lowest contribution rate of bedrock dissolution, whereas the value in 9# is the lightest (–9.3‰) with the highest contribution rate of bedrock dissolution. The proportion from host rock dissolution in 4# is higher than that in 1# and lower than that in 9#, while its mean drip water δ13CDIC value (–8.6‰) is higher than that of 9# and lower than that for 1#. This suggests that the prior calcite precipitation (PCP) processes in the unsaturated zone overlying the cave are responsible for the δ13CDIC value differences between different drip waters, and not bedrock dissolution. Furthermore, this study also demonstrates that the 87Sr/86Sr ratios of speleothems in the 1# and 4# mainly reflect the variation in the relative proportions from the soil system (soil water) and bedrock dissolution overlying the cave. It is, therefore, feasible to use the strontium isotopic signals of speleothems as an indicator for soil chemical weathering intensity, and consequently as a monsoon proxy in the study area.     

海德格尔论教化与真理——对柏拉图洞穴喻的一种生存论解读

在通常的理解中人们常常把＂教化＂理解为教育,将＂真理＂看作是关于世界的现成的知识,因而教化就是将真理作为一种现成的知识传授给他人。但是在西方人文主义的传统中,教化与教育是两个不同的概念,教化并不是主体对一种客观知识的掌握和传授,它应该在柏拉图的意义上被理解为以某种＂理念＂为原型的＂造形＂,教化本质上是人的存在状态的本质性的转变。海德格尔在关于柏拉图洞穴喻的生存论解读中,对教化与真理的关系作出了深刻的辨析。     

城市化对岩溶地下河水质的影Ⅱ向及其环境效应①②-以重庆市南山老龙洞地下河流域为例

目前我国已经进入快速城市化阶段,城市化的同时产生的生活污水及废弃物不断增加,对环境的污染加剧。为了了解人类活动尤其是城市化对岩溶地下河水质的影响,对重庆市南山老龙洞地下河流域上游的污水和老龙洞地下河出口处的河水的温度,pH．电导率、溶解氧和阴阳离子等水化学指标进行了一年的连续性观测。结果表明,老龙洞地下河的主要污染源是上游城镇产生的生活污水,各顷指标都超过了国家地下水质量标准,急需治理。     

丰都雪玉洞景区的开发和管理刍议

对雪玉洞景区的旅游资源条件进行了简要分析,厘清了景区在开发和管理过程中需要注意的环境保护、建筑设施布局、市场定位、安全保障等方面的问题,提出了解决问题的具体对策和措施.     

末次冰消期东亚夏季风突变性的石笋年纹层记录

从两支石笋年纹层的交叉定年，可确定年生长速率变化时间序列，本文结合氧同位素分析结果，讨论了新仙女木事件、阿弗罗德-波令暖期等百年至千年级全球性气候突变事件的转型方式、内部振荡旋回及冷暖／干湿组合特征，并且发现石笋年层厚度反映的气候变化过程与格陵兰CISP2冰芯具有相似的变化规律，证明石笋年纹层可以作为气候变化的代用指标。     

黄龙洞沉积的环境意义及旅游开发评价

对洞穴沉积物岩性进行分层描述 ,并取样进行了 C1 4、热释光及孢粉鉴定 ,确定沉积物时代为距今 1 4630± 1 90年～ 85 5 0± 75年 .岩性和孢粉组合特征显示洞内沉积经历了暖湿、温干、暖湿、再到温干的气候变迁 ,其生态环境属于稀树草原型 .通过与本区域周边地区 (临汾盆地、北京平原地区 )孢粉组合对比 ,判断黄龙洞所在太原盆地北部山区气候、生态环境及其变化趋势与我国北方地区大体是同步的 ,同时也存在一定差异 .     

Transmission of oxygen isotope signals of precipitation-soil water-drip water and its implications in Liangfeng Cave of Guizhou,China

According to systemically monitoring results of oxygen （hydrogen） isotope compositions of precipitation, soil waters, soil CO2, cave drip waters and their corresponding speleothems in Liangfeng Cave （LFC） in Guizhou Province, Southwest China, it is found that local precipitation is the main source of soil waters and drip waters, and that the amplitudes of those δ18O values of three waters （precipitation, soil water and drip water） decrease in turn in the observed year, which are 0‰ to -10‰, -2‰ to -9‰ and -6‰ to -8‰, respectively. Moreover, the δ18O values for three waters show a roughly simultaneous variation, namely, that those values are lighter in the rainy seasons, weightier in the dry seasons, and that the average δ18O value of drip waters is about 0.3‰ weightier than that of precipitation, which is modified by surface evaporation processes. We also find that oxygen isotope equilibrium is reached or neared in the formation processes of speleothems in LFC system, and that it is feasible to reconstruct paleotemperature and paleoprecipitation by using δ18O values of speleothems. However, it should be noted that surface evaporation would affect the oxygen isotope values in the study area.     

Asian summer monsoon precipitation recorded by stalagmite oxygen isotopic composition in the western Loess Plateau during AD1875―2003 and its linkage with ocean-atmosphere system

Based on 5 high-precision 230Th dates and 103 stable oxygen isotope ratios (δ18O) obtained from the top 16 mm of a stalagmite collected from Wanxiang Cave,Wudu,Gansu,variation of monsoonal precipita-tion in the modern Asian Monsoon (AM) marginal zone over the past 100 years was reconstructed. Comparison of the speleothem δ18O record with instrumental precipitation data at Wudu in the past 50 years indicates a high parallelism between the two curves,suggesting that the speleothem δ18O is a good proxy for the AM strength and associated precipitation,controlled by "amount effect" of the pre-cipitation. Variation of the monsoonal precipitation during the past 100 years can be divided into three stages,increasing from AD 1875 to 1900,then decreasing from AD 1901 to 1946,and increasing again thereafter. This variation is quite similar to that of the Drought/Flooding index archived from Chinese historical documents. This speleothem-derived AM record shows a close association with the Pacific Decadal Oscillation (PDO) between AD 1875 and 1977,with higher monsoonal precipitation corre-sponding to cold PDO phase and vice versa at decadal timescale. The monsoonal precipitation varia-tion is out of phase with the PDO after AD 1977,probably resulting from the decadal climate jump in the north Pacific occurring at around AD 1976/77. These results demonstrate a strong linkage between the AM and associated precipitation and the Pacific Ocean via ocean/atmosphere interaction. This rela-tionship will aid to forecast future hydrological cycle for the AM monsoon region,and to improve forecasting potential of climatic model with observation data from cave.     

Paleotemperature changes ver the past 3000 years in eastern Beijing, China:A reconstraction based on Mg/Sr records in a stalagmite

The Mg/Sr ratio in a stalagmite, which is directly proportional to DMg/Ca, the solid-liquid distribution coefficient of Mg, is proposed as a geochemical thermometer to estimate paleotemperature changes. The paleotemperature changein eastern Beijing over the past 3000 years has been reconstructed by using this thermometer in the stalagmite ZFFS-1 from Jingdong Cave. The records can be divided into two periods: 3000-2000 aBP, cool and wet, the air temperature averaging 9.8℃; and 2000 aBP-present, hot and dry, the air temperature being 1℃ higher than the mean value (11.7℃) of the past 3000 years. During 500-200 aBP, the air temperature was about 1.2℃ lower than that of the present, corresponding to the Little Ice Age in Europe. Like δ18O and δ13C, Mg/Sr (or DMg/Ca) reflects an obviously warming trend of the past 200 years. These results are supported by historic records.     

北京猿人洞穴堆积气候地层的再研究(英文)

周口店第一地点洞穴40余米厚的堆积层自下而上共分17层，新近测量的年代推前了近20万年，对堆支所含哺乳动物化石和孢粉资料进行聚类统计和因子分析，结合风化系数和微量元素含量等古气候代用指标，重新定量地描绘它所记录的古气候波动旋回，根据第2层TIMS测年为41万年BP，第14层上部是磁性地层测量的B／A界线，可以将该洞穴堆积层1－4层对比于深海岩芯δ^18O气候曲线的11－19段或中国黄土－－古土壤序列S4－S7，并且古气候旋回内的次级波动也可进行一定程序的对比。