Mineral magnetic record of Holocene environmental changes in Sägistalsee, Switzerland

The Holocene magnetic signature due to environmental change has been investigated in sediments from Sägistalsee, a small alpine lake in the Bernese Alps, Switzerland. The environmental signal in the mineral magnetic parameters of the sediments was compared with palynological and geochemical data. The types of magnetic minerals and their grain size reflect changes in the lake catchment, vegetation, and degree of erosional input. The concentration of the magnetic minerals, as expressed by isothermal and anhysteretic remanent magnetizations also reflect changes in vegetation, but may also be related to redox conditions during sedimentation. Climate influence on the mineral magnetic record has been recognized and interpreted as a consequence of the production of an authigenic mineral with particularly uniform magnetic properties during warmer stages and the influx of heterogeneous detrital magnetic mineral during cooler stages and under increased human activity.     

BOOK REVIEWS

Book Reviewed in this article: Introduction to Climatology for the Tropics . J. O. Ayoade. Conservation and Management of Natural Resources in the United States . Charles F. Bennett. The Keeping of Animals: Adaptation and Social Relations in Livestock Producing Communities . Riva Berleant-Schiller and Eugenia Shanklin, ed. The Evolution of Geographic Thought in America: A Kentucky Root Wilford A. Bladen and Pradyumna P. Karan, eds. Latin America: Geographical Perspectives , 2nd ed. Harold Blakemore and Clifford T. Smith, ed. The Rural Real Estate Market. Department of Geography Publication Series, No. 18 . Chris Bryant. Urban Geomorphology in Drylands . R. U. Cooke, D. Brunsden, J. C. Doornkamp, and D. K. C. Jones with contributions by J. Griffiths, P. Knott, R. Potter, and R. Russell. Italian Geography, 1960–1980. Meeting of the Status of the Geographic Research in Italy, 1960–1980. Treated under the auspices of Consiglio Nazionale delle Ricerche and organized by Istituto di Geografia Umana della Facoltà di Lettere e Filosofia dell'Università degli Studi di Milano , Giacomo Corna Pellecrini and Carlo Brusa, eds. The Changing Fenland . H. C. Darby. The Future for the City Centre . R. L. Davies and A. G. Champion, eds. Saudi Arabia, Energy, Developmental Planning, and Industrialization . Ragaei El Mallakh, Dorothea H. El Mallakh, eds. For We Are Sold, I and My People: Women and Industry in Mexico's Frontier . Maria Patricia Fernández-Kelly. The Great Lakes Forest: An Environmental and Social History . Susan L. Flader, ed. Regional Transformation and Industrial Revolution: A Geography of the Yorkshire Woolen Industry . Derek Gregory Crime in City Politics . Anne Heinz, Herbert Jacob and Robert L. Lineberry, eds. Revitalizing Cities . H. Briavel Holcomb and Robert A. Beauregard. Cartographic Relief Presentation . Eduard Imhof. H. J. Steward, Trans. Soviet Union: A Geographical Survey . S. V. Kalesnik and V. F. Pavlenko, ed. Cognition and Environment . Stephen Kaplan and Rachel Kaplan. Environmental Protection: The International Dimension . David A. Kay and Harold K. Jacobsen, eds. Mathematical Programming Methods for Geographers and Planners , James Killen. Gentrification Amid Urban Decline: Strategies for America's Older Cities . Michael H. Lang. The North Atlantic Sulphur System . Risto Laulajainen. The Jerusalem Cathedra: Studies in the History, Archaeology, Geography and Ethnography of the Land of Israel, Vol. 2 . Lee I. Levine ed. Jerusalem and Detroit: Recreation Planning and Management . Stanely R. Lieber and Daniel R. Fesenmaier, eds. Heartland and Hinterland: A Geography of Canada . L. D. McCann, ed. Scarborough Where We Live: The Residential Districts of Minneapolis and St. Paul . Judith A. Martin and David A. Lanegran. California: The Geography of Diversity . Crane S. Miller and Richard S. Hyslop. Palo Alto The Dilemma of Amazonian Development . Emilio F. Moran, ed. Boulder Nuclear Waste: Socioeconomic Dimensions of Long-Term Storage . Steve H. Murdock, F. Larry Leistritz, and Rita R. Hamm, eds. Boulder Communism and the Politics of Inequalities . Daniel N. Nelson, ed. The Los Angeles Metropolis . Howard J. Nelson. Dubuque An Historical Geography of Urban System Development: Tidewater Virginia in the 18th Century . James O'Mara. Procedures and Standards for a Multipurpose Cadastre . East Asia: Geographical and Historical Approaches to Foreign Area Studies . Clifton W. Pannell, ed. Dubuque Mackinder: Geography as an Aid to Statecraft . W. H. Parker. Beyond the Urban Fringe: Land Use Issues of Nonmetropolitan America . Rutherford H. Platt and George Macinko, eds. Recreation Geography of the USSR . V. S. Preobrazhensky and V. M. Krivosheyev, eds. Missouri: A Geography . Milton D. Rafferty The Invisible Farmers: Women in Agricultural Production . Carolyn E. Sachs. Cayman Islands Seashore Vegetation: A Study in Comparative Biogeography . Jonathan D. Sauer. Hillslope Materials and Processes . Michael J. Selby. Housing in Britain: The Post-War Experience . John R. Short The Study of Population: Elements, Patterns and Processes . George A. Schnell and Mark Stephen Monmonier. Columbus The Soviet Union: A Systematic Geography . Leslie Symons, ed. The Ottoman Slave Trade and Its Suppression . Ehud R. Toledano. The Impact of Recession on Industry, Employment and the Regions, 1976–1981 . Alan R. Townsend. Landslides and Their Control , 2nd ed. Quido Záruba and Vojtech Mencl. Translated from the Czech by H. Zárubová and V. Mencl.     

海相沉积氧化还原环境的地球化学识别指标

全球海洋在10-5.4亿年间演变成氧化环境,此后历经多次全球性的缺氧事件后演变到现在的氧化环境.海水和沉积物中多种无素的循环、分异和富集明显受氧化还原条件的影响.Mn、Mo、Cr、V和U等变价元素的溶解度随氧化还原条件的改变产生极大变化,导致沉积物中的元素含量分异:Ni、Co、Cu和Zn等在还原条件下形成硫化物沉淀,导致沉积物中对应元素的富集.这些元素的地球化学行为是古海洋氧化还原条件的灵敏指示剂,作为恢复古海洋氧化还原条件环境变化的地球化学指标.黄铁矿化程度(DOP)、生物樗化合物和Ce异常等也是沉积物氧化还原条件的常用判别指标.泥岩石研究中通常采用DOP、U/Th、自生U、V/Cr、Ni/Co和生物标志化合物等指标,碳酸盐岩则主要采用Ce异常指标.当前各种指标的定性分析都取得比较一致的结果,但是用一种或几种定量的地球化学指标来恢复整个古海洋的氧化还原环境目前还有很大的问题.     

吉林省珲春市黄松甸子砾岩型金矿床开采技术条件

本文重点论述吉林省珲春市黄松甸子砾岩型金矿床工程地质特征及基类型的划分，对矿床的工程地质条件给予定性和半定量评价，论述了矿床的开采技术条件。     

合成淀粉磷酸单酯影响因素的探讨

以木薯淀粉为原料,探讨了应用于造纸行业中具有一定取工的淀粉磷酸单酯合成的最佳工艺条件。     

Progress of the Climate Extension of Weather Research and Forecast(CWRF)Model Application in China

With the development of regional climate simulation, CWRF, the new generation regional climate model, is increasingly used in climate research because of its advanced capability and high skill. The CWRF application in China was introduced from three aspects: its modifications of WRF physics parameterizations, the construction of modeling domain and lateral boundary conditions, the case simulation study and comparison with RegCM, illustrating the accuracy and advantage of CWRF in regional climate simulations. Furthermore, two major CWRF developmental prospects in China were explored: one was to incorporate more accurate physical parameterization schemes and optimized multi-physics ensemble approach; the other was to nest CWRF in GCMs for short-term climate operational forecast and long-term climate change prediction and impact assessment. The status of CWRF applications in China was summarized and the outlook of its further development was pointed out, which provided a meaningful reference for more general research and application.     

四川渠县“8·8”特大暴雨引发的地质灾害分布特征与成因分析

2021年8月8日渠县遭遇特大暴雨袭击,引发新增灾害38处,不同程度加剧已有灾害点109处。文中基于实地调查资料,对特大暴雨引发灾害的特征和孕灾地质条件与灾害分布关系开展研究,对比研究了累计降雨量与新增灾害数量和已有灾害加剧程度之间的关系。结果表明：此次渠县特大暴雨引发新增灾害点主要为土质滑坡,占比94.7%;区域斜坡结构对灾害发生的影响程度最高;土质滑坡集中发生在300～325 mm累计雨量区间,高达27处,变形迹象加剧程度严重的灾害点23处,分布在累计雨量为337～348 mm区间内;为该县地质灾害防治区划与汛期地质灾害防御提供科学依据,为类似地区特大暴雨地质灾害防灾减灾提供参考。     

东秦岭古生代伟晶岩稀有金属成矿特色与成矿条件分析

东秦岭伟晶岩区是秦岭造山带规模最大、稀有金属矿化最丰富的伟晶岩区。该区稀有金属矿化种类齐全,产出贫矿、铀矿化、铍矿化、锂矿化和复杂稀有金属矿化伟晶岩,以锂矿化和铀矿化伟晶岩为主。稀有金属伟晶岩类型丰富,包括绿柱石-铌铁矿亚型、锂辉石亚型、锂云母亚型和钠长石-锂辉石型。伟晶岩内部结构分带型式多样,包括对称分带、分层和均一结构。铀矿化伟晶岩分带简单,铍矿化和复杂稀有金属矿化伟晶岩以对称分带结构为主,锂矿化伟晶岩具有多种内部结构分带型式。伟晶岩分异演化程度跨度大。结晶分异影响着复杂稀有金属矿化伟晶岩的成矿过程。该区主要产出古生代伟晶岩,形成于晚志留世—中泥盆世,集中于两期,处于晚造山-造山后阶段。伟晶岩形成时代与伟晶岩空间分布、岩浆岩分异演化程度、稀有金属矿化类型等关联不大。东秦岭地区中大面积不同时代花岗岩体的侵位、变质沉积岩地层的发育以及长期复杂的造山演化历史,包括地壳加厚和抬升,是形成高度分异演化的伟晶岩岩浆的有利地质条件。该区具有寻找铍矿和复杂稀有金属矿的潜力,且需要关注长石、石英和云母等矿物的综合利用。稀有金属伟晶岩的岩浆成因是未来研究的重要方向。     

西藏冈底斯南缘努日铜钨钼矿床地质特征与矽卡岩矿物学研究

西藏山南地区努日铜钨钼矿床位于冈底斯火山-岩浆弧构造带东段南缘,是新近探明的一个大型矽卡岩型铜钨钼矿床。矿区内出露有白垩系比马组和旦师庭组及大量晚白垩世和古近纪的侵入岩。矿区内的矽卡岩呈层状、似层状产在白垩系比马组地层中,矽卡岩矿物主要为石榴子石、辉石、硅灰石、角闪石、绿帘石、符山石等;金属矿物主要有黄铜矿、黄铁矿、辉钼矿、白钨矿、斑铜矿、黝铜矿等。电子探针分析结果表明,矽卡岩矿物中石榴子石主要以钙铁榴石和钙铝榴石为主,辉石主要为透辉石,角闪石属于镁角闪石-阳起石,帘石主要为绿帘石。矽卡岩类型在水平和垂向上具有较好的分带性,依次由石榴子石矽卡岩过渡到透辉石矽卡岩,再过渡到透辉石硅灰石矽卡岩,这种分带特征表现了流体交代作用的变化。矿化类型和矿化组合也具有一定的分带性,浅部以矽卡岩型钨矿化为主;随着深度的增加,逐渐过渡为脉状的铜矿体或铜钼矿体,在局部较深的钻孔中还有少量的斑岩型矿化,主要以铜矿化为主,伴有较弱的钼矿化。石榴子石组分在垂向和水平方向上均具有规律性的变化,由钙铁榴石占主体逐渐过渡为钙铝榴石占主体。成分剖面显示石榴子石的组分和化学成分随着环带的变化而变化,说明石榴子石是由一种脉动式流体形成的,可能是由流体化学成分的自身再平衡和生长过程中流体流量的改变而引起生长速率的改变共同实现的。通过含铁律比值(Kp)的计算,得出努日矿床形成于弱酸性、较强氧化状态。结合矽卡岩矿物分布和成分变化特征,推测努日矿区的矽卡岩可能是由深部侵入体分异出的热液沿着层间的破碎带或断裂,经过较远距离的运移,与地层中的碳酸盐岩发生交代作用而形成。渗透交代作用可能是形成矿区矽卡岩的主要原因,流体的温度和氧逸度变化对于形成不同的矽卡岩矿物具有重要作用。努日矿床的矽卡岩为浅部矽卡岩,可能存在统一的斑岩型-矽卡岩型成矿系统,深部具有较大的找矿潜力。     

南天山满大勒克蛇绿岩铬铁矿矿物学特征及其意义

满大勒克蛇绿岩属于南天山晚古生代蛇绿岩带,主要由蛇纹石化橄榄岩、玄武岩和含放射虫硅质岩组成。其中蛇纹岩富含铬铁矿,并具有豆荚状特征。显微镜观察和电子探针分析表明,铬铁矿具有明显的环带结构,从核部到边部呈现出由铬尖晶石到铬铁矿到磁铁矿的变化特征,元素组成上具有由富Al和Cr、贫Fe到贫Al和Cr、富Fe的变化趋势。利用铬铁矿(铬尖晶石)核部矿物的化学成分,得出铬尖晶石的结晶温度为1359～1394℃,平均1379℃;压力为2.76～3.00GPa,平均2.87GPa;相对于FMQ缓冲剂的地幔氧逸度为FMQ-1.50～FMQ-2.92log单位,平均值为FMQ-2.14log单位;地幔熔融程度F为16.7%～18.0%。结合已有研究成果,推测满大勒克蛇绿岩的基底橄榄岩单元源区为石榴石二辉橄榄岩,形成于亏损的软流圈地幔,对应的大地构造位置为弧前盆地。研究区铬尖晶石的环带特征显示其经历了温度由高到低、氧逸度由低到高的演变,反映了满大勒克蛇绿岩套的橄榄岩单元经历了高温高压的地幔环境(低氧逸度),之后随构造变动被推覆到地壳,定位之后又经历了区域变质作用的演化过程(高氧逸度)。