西昆仑康西瓦南部甜水湖一带下志留统与中泥盆统不整合界面的发现

在进行1：25万岔路口幅康西瓦南部甜水湖一带地质填图和实测地层剖面的过程中，在原划奥陶系冬瓜山组中采到了大量腕足、珊瑚类化石，经鉴定其形成时代为中泥盆世早期，并发现该地层与下伏下志留统温泉沟群呈微角度不整合接触。该不整合界面的发现充分证实甜水海微陆块经历过早古生代运动，说明该微陆块与扬子陆块具有相似的演化历史，二者具有明显的亲缘关系，为进一步探讨南、北古大陆边界提供了基础资料。     

“2006年中国桩工机械行业年会”在长沙召开

由中国工程机械协会桩工机械分会主办、湖南山河智能机械股份有限公司承办的“2006年中国桩工机械行业年会”于2006年10月22～26日在长沙召开，来自桩工机械生产企业、配套件厂、桩基础施工企业以及业内重要媒体等100个单位、150余位代表参加了会议，共同探讨中国桩工机械行业的新出路。     

安徽"两山一湖"地区地质环境问题

1前言“两山一湖”是指安徽省南部地区的黄山、九华山和太平湖及其周边地区。区内有被世人称之为“天下第一奇山”的黄山,国家级山岳风景名胜———九华山(中国四大佛教胜地之一),还有太平湖风景区、世界文化遗产———黟县西递、宏村古村落、国家级自然保护区———牯牛降、清凉峰。她是集世界文化、自然遗产于一身的旅游大区。更是拥有丰富的地质景观、地质遗迹和较多的岩溶景观,构成融自然风景、宗教圣地、休闲活动、科学考察和猎奇探险为一体的世界级旅游区,旅游资源十分丰富。由于人们缺乏必要的地学知识及相应的地质环境保护意识,“两…     

The effects of microbial activity on the geochemistry of highly acidic crater lakes： An example from Laguna Caliente, Poas volcano （Costa Rica）

Laguna Caliente is a crater lake hosted within the Poas volcano （Costa Rica） that is considered one of the most active volcanic systems of Central America. Laguna Caliente is characterized by extremely low pH （-1） and very high TDS values （up to 33700 mg/L）, although, in the last two decades, the lake volume has significantly changed, mainly in relation to variations of the fumarolic activity. In this work, we present the chemical and isotopic compositions of water and dissolved gases collected along the vertical profile of the lake in order to constrain the main processes that control its physical-chemical features. Water and gas samples were collected. Laguna Caliente has a Ca （Mg）-Cl （SO4） composition, typical of acid-brine lakes of active volcanic systems. Among dissolved gases, CO2 content, by considering the low pH, is particularly high （up to 18.1% by vol.）, and relevant amounts of oxygen （15.8. % by vol.）, preventing the formation of any anoxic hypolimnion, are also present at the maximum depth. Temperature and chemical species remain almost constant along the vertical profile, with the exception of F- that shows a moderate increase with depth and CI and SO4^2-, whose contents increase by more than 10% at the depth of 20 m, and, below 20 m, decrease to values similar to those measured at surface. This compositional stratification may be tentatively explained by the complex combination of, at least, three processes： （1） input of high-temperature volatiles from sub-lacustrine fumaroles, （2） loss of HCl and H2S from lake surface through evaporation, and （3） SO4^2- and CI consumption due to microbial activity at the bottom of the lake.     

Catastrophic and persistent environmental consequences of an acid crater-lake discharge, Chiginagak Volcano, Alaska

In early summer 2005, acidic, metal-laden water and clay-rich debris flooded down the flanks of the Chiginagak Volcano, Alaska. The estimated 3-million-m^3 discharge occurred during a rapid partial draining of a newly formed summit crater lake. Twenty-seven kilometers downstream from the source, Mother Goose Lake, a 500-million-m3 lake, was acidified from surface to bottom （pH ranged from 2.9 to 3.06）. All aquatic life was killed and salmon spawning runs were eliminated. The flood was accompanied by a simultaneous release of caustic volcanic gas and aerosols that followed the flood flow-path, and caused defoliation and necrotic leaf damage to vegetation in a 30-km^2 area along and above affected streams. In September 2005, approximately 1.4 million m^3 of acidic water remained and continued to drain from the summit crater lake. Water sampled 8 km downstream after considerable dilution from glacial meltwater was a weak sulfuric acid solution （pH-3, SO4^2- ～500 mg/L, and SO4^2-/Cl～10）. Cation proportions decreased in the order of Ca〉Fe〉Al〉Mg〉Na〉K. The eightfold predominance of Ca^2＋ over Mg^2＋ may reflect some dissolution of anhydrite, but only about 30% of the SO4^2- can be balanced by Ca^2＋. The anomalously high concentrations of Fe （-25 mg/L） and A1 （-18 mg/L） are derived from rock dissolution under the acidic conditions within the crater lake, and appear to be the most serious environmental threat in terms of metals. Further downstream, at stream and lake sites ranging from 8 to 40 km from the source, concentrations of cations remained high and hazardous metals such as As, Cr, and Cu were elevated well above background levels. Copper concentrations exceeded the U.S. Environmental Protection Agency＇s chronic exposure limit for aquatic life at most sampled sites and several sites exceeded the acute exposure limit.     

西部高山冰川阻塞湖引起的突发性洪水灾害研究

我国西部地区经常发生洪水灾害。此为当地干旱区自然环境状况的特点。作者经过实地考察中天山地区与喀喇昆仑山地区，认为这是由于冰川阻塞湖引起的突发性洪水灾害，并且获得关于洪水的第一手资料。认为该洪水类型具有暴发突然、变化快、历时短暂、发生地受冰川环境影响大等特点。初步判定关于冰川阻塞湖突发性洪水的排水机制可能。通过对叶尔羌河、昆马力克河及四棵树河的详细研究，利用混沌及分形等数理方法，计算出相关特性定量指标。发现可预报洪水序列与阻塞湖库容量有正相关关系。结合整个西部地区的冰川分布进行整合分析．发现冰川阻塞湖引起突发性洪水的发生规律。结合分析阿尔泰山、祁连山及西藏地区地理环境特点，认为塔里木盆地周边地区是冰湖洪水的突发区。加强对冰川阻塞湖洪水的研究，希望对未来的西部大开发，尤其是基础设施建设和保护起到辅助指导作用。     

辽宁张强盆地聚煤与构造特征

张强盆地是辽宁晚中生代半地堑式断拗盆地，呈萁状。同生构造控制了盆地的形成、沉积及演化。湖滨三角洲平原聚煤环境、湖泊环境的成油、富煤区与古构造、古气候、占地理的演化紧密相关。与邻区协尔苏盆地、三台子盆地沉积上有相似性及差异性。通过对沉积特征的分析，对今后找矿工作有一定的指导意义。     

藏西北结则茶卡湖晚更新世以来演化及气候环境

结则茶卡位于藏北高原湖盆区西北部,喀喇昆仑山与昆仑山交汇部位的西南侧,处于班公湖—怒江结合带与红其拉甫—双湖结合带之间,湖面海拔高度4525m.在其拔湖325m附近明显存在一条高位湖岸线,从该湖岸线到湖面,发育了各级较为连续的湖积阶地和众多保存较好的湖岸堤、湖蚀槽、湖蚀柱和湖蚀台地.沿湖岸不同高度上的湖积物U系年龄分别为(14.2±1.2)kaB.P.(T2)、(38.0±3.5)kaB.P.(T4)和(41.6±3.2)kaB.P.(T5),根据湖面下降幅度推算出结则茶卡高位湖积层形成年龄大致在120~90kaB.P..晚更新世以来结则茶卡处于封闭演化体系中,湖泊的萎缩主要与气候干旱、少雨有关,湖面平均退却速度3.31mm/a.大约晚更新世初期,青藏高原存在着一个高湖面,大致在100kaB.P.开始,青藏高原泛湖期从西向东逐渐结束,其气候也从西向东可能逐渐变为干旱、少雨.     

四海龙湾玛珥湖沉积物中碱流质火山灰的来源及其意义

四海龙湾玛珥湖位于东北新生代龙岗火山区内,在玛珥湖沉积物距湖底69-70cm处分离出新鲜的火山灰。根据火山灰产出的层位、原生沉积特征、形貌和碱流质化学成分特征,属于长白山天池火山公元1199-1200年大喷发的产物。这一结果不仅表明天池火山历史时期大喷发的规模比原来估计的还要大,并且为建立千年以来四海龙湾沉积物及古气候演化的时间标尺提供了依据。     

尕海湖DG03孔碳酸盐含量及其环境意义

通过对尕海DG03孔岩芯碳酸盐含量的测定,表明碳酸盐含量指标较好地记录了尕海湖地区自冰消期晚期以来的气候环境变化。对阿勒罗德暖期和新仙女木期都有较好的反映,并揭示出早全新世气候变暖且波动明显,中全新世早期暖湿,后期温凉偏干,晚全新世气候明显变干,早期较为寒冷,后期偏暖。碳酸盐含量的变化反映了湖水的浓缩程度,与湖泊所处的沉积阶段相联系,同时与岩性特征所反映的环境也有关。在风成作用堆积的粉砂至中砂层,碳酸盐含量降至很低;在滨湖相沉积的细砂层,碳酸盐含量也较低,因此,碳酸盐含量指示的气候环境意义应与岩性及其他指标相结合进行分析,方可得到可信的结论。