反循环中心取样雾化钻探应用于砾岩型金矿取样地质效果及其编录方法     

刘宝成  袁力 《吉林地质》1994,13(2):75-81

中心取样钻探是一种全新的钻探方法，具有效率快、取样准确、岩样采取率高的特点。可用于砾岩型金矿勘探评价，获取的矿层深度、品位、厚度、岩心采取率等均能满足地质要求，利用回返物质能够进行正常地质编录。  相似文献   

新疆金矿床类型及找矿方向的研究   总被引：2，自引：2，他引：2  

彭守晋 《矿产与地质》1994,8(5):311-316

新疆金矿床划分为绿岩型、碎屑岩一碳酸盐岩－硅质岩型、变质碎屑岩型、火山岩型、侵入岩内及内外接触带型、伴生金及沉积型等７种类型，指出了火山岩型为区内最佳矿床类型，有很大的找矿前景．并探讨了地球化学场及地壳类型、构迟地质环境等方面对原生金矿床成矿的控制作用，提出了今后找金矿方向的建议．  相似文献   

与碱性花岗岩有关的稀有稀土矿床   总被引：2，自引：0，他引：2  

林德松 《矿产与地质》1994,8(6):401-406

概述了含矿碱性花岗岩产出的地质背景，含矿岩体的主要特征。根据岩石中暗色矿物与主要成矿元素的关系，将碱性花岗岩矿床划分为３种矿化类型：含Ｎｂ（Ｓｎ）黑云母花岗岩；含Ｎｂ（Ｓｎ）、ＨＲＥＥ钠铁闪石－钠闪石花岗岩；含ＬＲＥＥ霓石花岗岩，并指出，碱性花岗岩矿床在我国北部边区和攀西裂谷带具有良好的成矿前景。  相似文献   

可可西里地区乌兰乌拉湖湖泊环境变迁及古人类活动遗迹   总被引：4，自引：1，他引：4  

胡东生  王世和 《干旱区地理》1994,17(2):30-37

通过对可可西里地区及在乌兰乌拉湖所发现古人类活动遗迹的综合研究，认为乌兰乌拉湖地区自晚更新世末期以来，湖泊环境发生了由湿润（3×104aB．P．以前）──温暖（2×104aB．P．前后）──干暖（1×104aB．P．以前）──冷干（1×104aB．P．以来）的变化，湖水也产生了多次进退变化，与之相适应的古人类活动也发生了迁徒变化。  相似文献   

博斯腾湖流域气候及湖陆风   总被引：8，自引：0，他引：8  

王容  杜勇 《干旱区地理》1994,17(3):90-94

通过流域多个气象站的资料，分析了流域气候条件，并通过对湖区测点的气象观测资料与陆区测点－ 焉耆站的同步资料对比分析，讨论了博斯腾湖区域小气候其湖陆风特征。  相似文献   

华南沿海老红砂的成因与红化作用   总被引：17，自引：0，他引：17  

吴正  黄山 《地理学报》1994,49(4):298-306,T001

根据野外调查和室内实验分析，以及测年数据，本文讨论了华南沿海老红砂的成因、年龄与形成环境。认为老红砂是晚更新世末次冰期海岸风沙堆积，红色特征与亚间冰期的温暖古气候有关。在湿热气候下，古风成砂中含铁硅酸盐矿物氧化生成赤铁矿，而使无色石英沙粒染成红色，是其红化的主要机制。风成砂形成红色的时间不超过１万年。  相似文献   

The Evolutionary History of Ore-forming Processes of Metallic Ore Deposits in Northern Guangxi1     

Chen Yuchuan  Mao Jinwen  Wang Ping'an 《《地质学报》英文版》1995,8(2):155-170

Abstract The northern Guangxi region is an important rare metal, rare earth metal and polymetallic metallogenic province. In the region there exist five metallogenic series and two metallogenic subseries, whose metallogenesis shows features of polycyclic spiral evolution throughout the geological history. As far as various cycles are concerned, mantle-derived ore substances were reduced while crust-derived ore substances increased from early to late times; in the whole geological evolutionary history, mantle-derived substances decreased gradually while crust-derived ones increased. Meanwhile ore element associations became more and more varied. In terms of space, mineralization migrated from the old basement outwards, i.e. from west to east during the Precambrian, and from north to south during the Phanerozoic, and again from east to west during the Yanshanian.  相似文献   

A note on the chemical composition of lake water in the Laguna Amarga,a saline lake in Patagonia,Chile     

Y. Saijo  O. Mitamura  M. Tanaka 《International Journal of Salt Lake Research》1995,4(2):165-167

The chemical composition of lake water in Laguna Amarga, a small, shallow, saline lake near the Torres del Paine National Park (at 51°S), Chilean Patagonia, was studied in January, 1993. The water was strongly alkaline (pH 9.4) conductivity was 71.4 mS cm^–1, and salinity was 77 g L^–1. The major ions were sodium and sulphate.  相似文献   

Coastal Massachusetts pond development: edaphic,climatic, and sea level impacts since deglaciation     

Marjorie Green Winkler  Patricia R. Sanford 《Journal of Paleolimnology》1995,14(3):311-336

Kettle ponds in the Cape Cod National Seashore in southeastern Massachusetts differ in their evolution due to depth of the original ice block, the clay content of outwash in their drainage basins, and their siting in relation to geomorphic changes caused by sea-level rise, barrier beach formation, and saltmarsh development. Stratigraphic records of microfossil, carbon isotope, and sediment changes also document late-glacial and Holocene climatic changes.The ponds are separated into 3 groups, each of which follow different development scenarios. Group I ponds date from the late-glacial. They formed in clay-rich outwash, have perched aquifers and continuous lake sediment deposition. The earliest pollen and macrofossil assemblages in Group I pond sediments suggest tundra and spruce-willow parklands before 12 000 yr B.P., boreal forest between 12 000 and 10 500 yr B.P., bog/heath initiation and expansion during the Younger Dryas between 11 000 and 10 000 yr B.P., northern conifer forest between 10 500 and 9500 yr B.P., and establishment of the Cape oak and pitch pine barrens vegetation after 9500 yr B.P. Sedimentation rate changes suggest lowered freshwater levels between 9000 and 5000 yr B.P. caused by decreased precipitation on the Atlantic Coastal Plain. Lake sediment deposition began in the middle Holocene in Group II ponds which formed in clay-poor outwash. These ponds date from about 6000-5000 yr B.P. In these ponds sediment deposition began as sea level rose and the freshwater lens intersected the dry basins. The basal radiocarbon dates of these ponds and stable carbon isotope analyses of the pond sediments suggest a sea-level curve for Cape Cod Bay. Holocene topographic changes in upland and the landscape surrounding the ponds is reconstructed for this coastal area.Group III ponds in the late Holocene landscape of the Provincelands dunes originated as interdunal bogs about 1000 yr B.P. and became ponds more recently as water-levels increased. Peat formation in the Provincelands reflects climatic changes evident on both sides of the Atlantic region.This is the 8th in a series of papers published in this special AMQUA issue. These papers were presented at the 1994 meeting of the American Quaternary Association held 19–22 June, 1994, at the University of Minnesota, Minneapolis, Minnesota, USA. Dr Linda C. K. Shane served as guest editor for these papers.  相似文献   

A sedimentary facies model for perennial and meromictic saline lakes: Holocene Medicine Lake Basin, South Dakota, USA     

Blas L. Valero-Garcés  Kerry R. Kelts 《Journal of Paleolimnology》1995,14(2):123-149

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