绥阳双河洞发育对区内地表水系变迁影响

双河洞是我国已探明长度最长洞穴,也是世界第一长白云岩洞穴。为全面了解其形成机理,本研究基于双河洞探测和地表调查资料,以双河洞发育特征,区内地表河床地貌、地形和现代水系特征为研究对象,以双河溶洞发育演化模式为基础,开展双河洞发育演化对区内地表水系变迁影响研究。认为：（1）研究区地表水系随双河溶洞发育演化而变迁;（2）双河洞穴发育,使让水沟地表水通过洞穴向池武溪排泄,将独立的让水沟和池武溪两个流域变成一个流域;（3）双河洞发育引起地下水袭夺地表水,形成断尾河4处;（4）随着地壳抬升地下水位下降,水力梯度增大,地下水运输能力增强,加剧洞穴发育,为地下水袭夺地表水提供良好的水势差与过水条件,是研究区水系变迁的主要动力。     

湖北永兴洞降水对2015年厄尔尼诺的响应

通过对湖北永兴洞为期3年（2013年6月至2016年7月）的地表降水δ¹⁸O观测,发现该地点降水δ¹⁸O在2015夏季显著偏正。利用HYSPLIT后向轨迹方法对永兴洞降水水汽来源进行分析,结果表明在厄尔尼诺事件的影响下2015年夏季来自远源印度洋的水汽显著减少,而近源太平洋水汽相对增多,即降水δ¹⁸O因"环流效应"而偏正。本研究提供的观测证据表明永兴洞石笋δ¹⁸O记录在重建ENSO主导下的亚洲季风大气环流方面具有重要潜力。

     

末次盛冰期百年尺度气候变化的南京石笋记录

据年层计数和TIMSU系测年结果,建立了南京汤山葫芦洞YT石笋年际精度时间标尺(18000～14000aB.P.)。除石笋顶部5mm层段外,高分辨率的δ18O、灰度和年层厚度3种指标在百年尺度上具有相当一致的对应关系,表明这3种指标对气候因素变化响应比较敏感。综合石笋δ18O和本区古植被资料,估计末次盛冰期和波令暖期年均温分别达7℃和15℃。石笋揭示的末次盛冰期气候可进一步划分为4个阶段:1)18150～16900aB.P.,年均温和洞穴湿度逐步下降;2)16900～16100aB.P.,年均温和洞穴湿度相对稳定,可进一步划分为3个暖峰和两个冷谷;3)16100～15600aB.P.,年均温快速下降,按氧同位素平衡方程计算,其冷谷可能接近于0℃,但洞穴湿度比前期下降幅度并不大;4)15600～14750aB.P.,年均温和洞穴湿度比较稳定。这种气候演化的阶段性和突变性与北大西洋地区气候记录可以对比,反映极地与东亚季风气候受共同的驱动机制支配。从石笋4种指标(δ18O、δ13C、灰度和年层厚度)的功率谱图中识别出不同尺度的太阳活动周期成分,其中80aGleissberg周期特别显著,表明末次盛冰期边界条件下太阳活动仍是短尺度气候变化的主要驱动力。     

北京猿人洞堆积旋回与黄土和深海气候旋回对比

北京猿人洞13个堆积层可划分为7个堆积旋回。每个旋回早期的堆积层(砂、粉砂、粘土和钙扳层),含有暖温带气候特征的哺乳动物和孢粉组合;晚期的堆积层(洞穴角砾与巨砾层),含有温带较干冷气候特征的哺乳动物和孢粉组合。堆积层年代测定数据表明北京猿人洞7个堆积旋回形成于更新世中期,年代为128-730ka,与中国黄土层L2-S7,相当,可与深海氧同位素阶段6-19和气候旋回C-I对比。北京猿人在此洞断续生活了约35万年,即从距今约60万年的第5堆积旋回(δ18O第14阶段)至距今约25万年的第2堆积旋回(δ18O第8阶段)。     

Dolomite in caves: Recent dolomite formation in oxic, non-sulfate environments. Castañar Cave, Spain

Dolomite is a common mineral in the rock record but rare in recent superficial environments. Where it does occur, it is related to anoxic, sulfate-rich environments and microbial activity. The occurrence of some dolomite deposits in caves, however, indicates that dolomite formation is also possible in oxic, non-sulfate settings. Dolomite is forming at 17 °C and in oxic-vadose conditions on the host rocks and aragonite speleothems of the Castañar Cave, Cáceres, Spain. It appears as spheroids and dumbbells 50–300 μm in diameter that internally consist of micron-sized rhombic to rounded crystals. Initially this dolomite is Ca-rich, non-stoichiometric and poorly ordered. Mg-rich solutions allow the precipitation of metastable Mg-rich carbonates, such as huntite. This soon transforms into this Ca-rich dolomite, which later “ages” to form a more stoichiometric dolomite. These dolomites show similarities to those grown under anoxic, sulfate-rich conditions and their presence in caves provides a different setting that may contribute to the understanding of the “dolomite problem”, including their initial formation and later recrystallization processes.     

富源刺托洞旧石器遗址初探

富源刺托洞的旧石器文化是适应岩溶地貌发育环境的产物,形成以小型石片、刮削器为主体的石器工业;当时的气候总体上是在热带、亚热带气候至暖温带之间波动,形成的动物群为非典型的大熊猫-剑齿象动物群(Ailuroooda-Stegodon fauna)可与晚更新世的柳江动物群(西畴动物群)对比;遗址时代为晚更新世,地质年龄测定(14C)＞4×104a.     

褒禅山华阳洞的形成机理及保护意义

褒禅山华阳洞主体发育于二叠系栖霞组灰岩中,是含山地区重要的地质遗迹之一。笔者从区域地质演化过程入手,针对岩溶洞穴发育的物质基础、局部构造条件、水流的定向溶蚀及新构造运动等方面进行综合研究,简要分析了华阳洞的形成机理,并从地学研究、旅游价值等方面阐述了对其保护的重要意义。     

Preliminary investigation of Late Pleistocene fauna from Ryonggok Cave No. 1, Sangwon County,North Hwanghae Province,Democratic People's Republic of Korea

The investigation of a limestone cave on the Ryonggok-ri of Sangwon County, North Hwanghae Province, DPRK, has yielded many faunal remains including Late Pleistocene deer, brown bears and horses. Uranium series dating of fossil teeth yielded dates of ~72ka at the base of Layer 2 – the bone-bearing unit – and ~44ka at the top. The rich and diverse mammal remains of Ryonggok Cave No. 1 are indicative of warm and humid temperate conditions during the Late Pleistocene, and reflect the presence of both dense forests and open grassland. In addition, pollen and spores from the site include two families and 24 genera of trees, six families and a genus of grasses and herbs, and two families and six genera of ferns, corroborating the environments inferred from the faunal remains.     

Legal protection for caves in the United States

This study reviews significant state and federal laws that can be used to protect karst, caves, and associated unique minerals and biota. The first state cave protection act was passed in Colorado in 1883; unfortunately it was repealed in 1971. From that modest beginning there are now a total of 22 states, Puerto Rico, and the Cherokee Nation that have specific cave protection acts. Most of these have been legislated during the last 20 years. There are a number of laws on the federal level that can be used for cave protection. The most important of these is the Federal Cave Resources Protection Act of 1988, which mandates cave conservation for many federal land management agencies. The Endangered Species Act of 1973 and the Federal Archaeological Resources Protection Act of 1976 can also be of significant use in the conservation of caves on federal land. The effects of these acts are variable. One factor is how important agency officials and law enforcement officers regard caves. It has not been unusual that little was done in the way of protection or prosecution even when the perpetrators have been apprehended. This attitude is changing rapidly primarily because those involved in enforcing the laws have been educated to the uniqueness and values of caves and their contents.     

Influences of agricultural practices on water quality of Tumbling Creek cave stream in Taney County,Missouri

Influences of agricultural practices on water quality of the Tumbling Creek cave stream are of particular interest because of the karst nature of the area and the recent implementation of a Better Management Practice (BMP). Water quality parameters, measured bi-weekly during one year, consisted of pH, turbidity, water temperature, specific conductivity, total dissolved solids, alkalinity, and chloride. Heavy metals, nutrient and bacteria levels were also monitored during the study. Effects of land use were most obvious in turbidity, nitrate, chloride, and bacteria levels. Sites within the recharge area that pose a major threat to its water quality were identified. Results provide a baseline for these water quality parameters and their seasonal variability that can be used in future studies to address the effects of water quality and stream sediment contamination on the caves ecosystem and to determine the effectiveness of the BMP implemented in this karst area.