Anthropogenic influence on the organic fraction of sediments in two contrasting estuaries: a biochemical approach

Abundance and biochemical composition of organic materials in sediments of the estuaries of Mundaka and Bilbao (SE Bay of Biscay) were analysed to assess the effect of organic wastes released to these systems. Organic and labile contents were higher in the sediments of Bilbao, denoting organic enrichment with poorly decomposed materials by human dumping. Spatially, organic matter distribution skewed seaward in Bilbao and upward in Mundaka, in agreement with the location of major point sources of sewage. Labile material, proteins and protein:carbohydrate ratio showed upward increases in both estuaries, attributed to the oxygen restrictive conditions to decompose organic materials. Vertical distribution of organic components into sediments reflected the history of human activities. In Bilbao, the significant reduction of organic and labile compounds, and the decrease of protein:carbohydrate values in top layers seem a result of recent remedial actions to reduce urban sewage inputs and improve environmental conditions. Higher contributions of proteins and lipids were associated with anthropogenic materials, and higher contributions of carbohydrates with autochthonous materials. High protein:carbohydrate values indicate poorly decomposed materials of human origin. The close relationship of carbohydrates with chloropigments in Mundaka suggests that phytobenthic populations and derived detritus contributed to a greater extent to the organic fraction in this estuary.     

Continental- Margin Structure of Northeast China and Its Adjacent Areas

The continental margin of Northeast China and its adjacent areas is composed of two tectonic belts. The inner belt is a collage made up of fragments resulting from breakup of an old land with the north part related to the evolution of the Palaeo-Asian Ocean and the south part to the evolution of the Palaeo - Pacific Ocean. The outer belt is a Mesozoic terrane, which is a melange made up of fragments of the Late Palaeozoic to Early Mesozoic oceanic crust and the Late M esozoic trench accumulations.There existed another ocean-the Palaeo - Pacific Ocean during the period from the closing of the Palaeo-Asian Ocean to the opening of the modern Pacific Ocean or from the Devonian to Jurassic, and the ocean-floor spreading of the Palaeo - Pacific Ocean led to the formation of the above-mentioned tectonic belts. The development of the strike-slip fault system after the Late Jurassic and the formation of an epicontinental volcano -plutonic rock belt in the Late Cretaceous to Early Tertiary are attributed to the i     

专题地图学的系统方法

1992年德国柏林自由大学出版了著名教授U.Freitag的论文集《Cartographic Conceptions》。我们认为其中有些论文应介绍给我国地图学界的同仁,故而与作者进行了联系,U.Freitag教授函复说:“……当然,你们可以选择并译出任何对中国读者适用的文章。”为此本刊组织翻译了其中几篇,今后将陆续刊载,以飨读者。     

闽北政和地区晋宁期变质岩系的变形变质作用

政和地区变质岩石形成于晋宁期,遭受了四期复杂的构造变形作用。其中,D_1、D_2和D_3发生于晋宁期。D_2期形变造就了区域性宏观面理构造和松源复背斜,岩石面理产状不代表原始沉积层理,属轴面叶理。D_4期变形为后期加里东运动的产物。变质岩石由绿泥石—黑云母带、石榴石带、十字石带和矽线石带组成一个热背斜式递增变质带,热背斜形态接近于松源复背斜。本区晋宁期变质作用可分为早期、主期和晚期三个变质阶段,各变质带的PTD轨迹均为顺时针,类似于陆—陆碰撞造山带的PTt轨迹。     

THE GEOMETRY OF MULTIVARIATE OBJECT PREPROCESSING

The geometric properties of three common object-preprocessing transformations(constant sum,orclosure;constant length,or normalization;and maximum value,or ratioing)are investigated.Anargument is made for using absolute values in the constant sum and maximum value transformations.In general,each transformation distorts the shape and dimensionality of patterns in the data:transformed data lie on(C-l)-dimensional surfaces in the original C-dimensional space.A data set thathas been closed by one of these transformations can be reopened if a vector containing the constant sums,constant lengths or maximum values of the original objects was retained.Transformed data sets may befreely interconverted among these three transformations without the loss of information.     

热幔柱构造—一种新的大地构造理论

热幔柱构造──一种新的大地构造理论赵国春，吴福元（地球科学系）自６０年代末板块构造理论问世以来，经过地质学家近３０年的努力不懈地发展和完善，这一理论在解释全球板块边缘上各种地质作用方面获得巨大成功。然而，在解释远离板块边缘或板块之下各种地质作用方面，...     

变质流体的缓冲作用及其理论意义

变质流体的缓冲作用及其理论意义赵国春（长春地质学院，长春１３００２６）关键词变质流体，内部缓冲作用，外部缓冲作用有关变质流体的内部缓冲作用和外部缓冲作用的认识是近年来变质地质学研究领域取得的重要进展之一。人们早已意识到变质流体在变质作用过程中可能起着...     

闽北政和地区晋宁期变质岩系的构造变形特征

通过宏观和微观构造的详细研究表明,政和地区变质岩石共经历了四期构造变形作用。其中,前三期构造变形作用发生于晋宁期,第四期构造变形作用为后期加里东运动叠加的产物,四期构造变形作用所形成的构造形迹各不相同。变质岩石的区域性面理是第二期构造变形作用形成的轴面叶理,不代表原始沉积层理的产状。