昆明市东川拖布卡金矿矿石岩石学研究   总被引：2，自引：0，他引：2  

张学诚  高俊彩 《云南地质》2006,25(3):276-285

中-低温热液型拖布卡金矿，与碱性（钠质）岩浆作用密切相关，尤以与纳长斑岩、二长斑岩最为明显。三类矿源岩石组合提供金质。自然金、显微裂隙金及包裹金组成金的主要赋存状态。提出拖布卡-播卡金矿成矿模式。  相似文献   

Application of multivariate spatial analysis in scale-based distribution and source study of PAHs in the topsoil: an example from Tianjin,China     

X. J. Wang  R. M. Liu  K. Y. Wang  J. D. Hu  Y. B. Ye  S. C. Zhang  F. L. Xu  S. Tao 《Environmental Geology》2006,49(8):1208-1216

Polycyclic aromatic hydrocarbons (PAHs) in soil originate from various sources under different spatial scales. Coregionalization analysis is more revealing than univariate geostatistical analysis. Scale-dependent spatial features of variables reflect different sources of spatial variability. In this study, 188 topsoil samples in the Tianjin area were collected. The contents of 16 PAHs and soil background properties were determined for all samples. A multivariate geostatistical approach was used for multi-scale spatial analysis for PAH compounds. Results show that coal combustion was the major source for the spatial distribution patterns of PAHs in the topsoil of the studied area. It worked mainly at the short-range scale (5–10 km). Significant spatial variation patterns were identified. In contrast, no significant spatial distribution trends at the nugget (0–5 km) or long-range scales (10–50 km) were seen. Long-range transport and site contamination of PAHs might not be key contributors in forming the distribution pattern of PAHs in the topsoil of Tianjin area.  相似文献   

Nitrous oxide in fresh water systems: An estimate for the yield of atmospheric N2O associated with disposal of human waste     

W. A. Kaplan  J. W. Elkins  C. E. Kolb  M. B. McElroy  S. C. Wofsy  A. P. Durán 《Pure and Applied Geophysics》1978,116(2-3):423-438

The N₂O content of waters in the Potomac and Merrimack Rivers was measured on a number of occasions over the period April to July 1977. The concentrations of dissolved N₂O exceed those which would apply in equilibrium with air by factors ranging from about 46 in the Potomac to 1.2 in the Merrimack. Highest concentrations of dissolved N₂O were associated with sewage discharges from the vicinity of Washington, D.C. and analysis indicates a relatively high yield, 1.3 to 11 percent, for prompt conversion of waste nitrogen to N₂O. The yield could be even higher if bubbles originating in sediments should contain as little as 0.3 percent N₂O. Measurements of dissolved N₂O in fresh water ponds near Boston demonstrate that aquatic systems may provide both strong sources and sinks for atmospheric N₂O.  相似文献   

滇西北中甸地区休瓦促岩浆热液型Mo-W矿床S、Pb同位素对成矿物质来源的约束   总被引：7，自引：5，他引：2  

王新松  毕献武  胡瑞忠  冷成彪  余海军  尹光侯 《岩石学报》2015,31(11):3171-3188

滇西北中甸地区位于义敦岛弧南段,近年来勘探及研究工作发现区内燕山晚期发育有一期重要的Mo-Cu-(W)矿化,明显区别于义敦岛弧北段同期的Sn-Ag-Pb-Zn多金属矿化,也不同于同地区印支期大量发育的斑岩型Cu矿化。目前,中甸地区燕山晚期Mo-Cu-(W)矿化成矿物质来源研究相对较弱,尚不能很好地解释这些成矿作用主要成矿元素存在差别的原因。休瓦促矿床是中甸地区代表性的燕山晚期大型岩浆热液型Mo-W矿床,前人定年结果显示成矿年龄为~83Ma。矿区内发育有三阶段的晚白垩世花岗岩,岩性主要有黑云母花岗斑岩、二长花岗岩和碱长花岗岩;且碱长花岗岩体下方还发育有萤石-长石似伟晶岩脉。矿化类型主要为石英脉型、近石英脉蚀变花岗岩型和斑岩型Mo-W矿化;矿体主要产在岩体内部,受控于北北西向断裂构造。蚀变类型有钾化、云英岩化、绢云母化及硅化等。流体包裹体测温显示成矿流体为含CO2的中高温(146.6~550.0℃),中低盐度(3.15%~12.51%NaC leqv)的H2O-NaC l热液,可能主要来自于岩浆期后热液。多种金属硫化物与燕山晚期花岗岩具有一致的初始Pb同位素组成(206Pb/204Pb=18.610~19.460,207Pb/204Pb=15.606~15.747,208Pb/204Pb=38.815~39.410),显示其成矿物质可能主要源于壳源岩浆作用,S同位素特征(δ34SVCDT:2.07‰~4.33‰)也显示其来自于岩浆作用。通过对比休瓦促Mo-W矿化、义敦岛弧北段同期的Sn-Ag-Pb-Zn多金属矿化及中甸地区印支期斑岩型Cu矿化,这三种与岩浆有关的热液矿化的S、Pb同位素及岩石地球化学性质,发现这三种矿化的成矿岩浆与相应的成矿元素均具有较好的成矿专属性;并指示着在燕山晚期陆内环境下,中甸地区的Mo-Cu-(W)矿化成矿物质来源于加厚的中基性下地壳部分熔融而形成的I型花岗岩,义敦岛弧北段的Sn-Ag-Pb-Zn矿化则主要来源于中酸性变沉积岩地壳的部分熔融而形成的A型花岗岩;而中甸印支期斑岩型的Cu矿化则与幔源岩浆作用有着密切的关系。  相似文献   

Quantitative sediment source ascription using magnetic measurements in a reservoir-catchment system near Nijar,S.E. Spain     

Lizhong Yu  Frank Oldfield 《地球表面变化过程与地形》1993,18(5):441-454

The magnetic properties of sediments from a dried-out reservoir and its inflowing streams were measured to provide a basis for sediment source determination. Quantitative estimates of source component proportions in the reservoir sediments were made using linear programming procedures. The study confirms that this type of research must be based on a detailed knowledge of the relationship between magnetic properties and particle size in both the sediments and the potential sources. In the case of the site studied, the Isabel II reservoir, near Nijar, S.E. Spain, the sediments generated by contemporary surface processes within the reservoir catchment fail to reflect fully the 19th century material largely responsible for the rapid infill of the reservoir. An additional source type, namely unweathered schist-derived material not represented in the fine sediments sampled within channels upstream from the reservoir, has to be included in the model before calculations of source component contributions can be made. It is inferred that one or more high magnitude, low frequency event outside the amplitude of the most recently operating processes was largely responsible for the infilling of the reservoir.  相似文献   

云南富乐铅锌矿床地质、地球化学及成因   总被引：5，自引：3，他引：2  

崔银亮  周家喜  黄智龙  罗开  念红良  叶霖  李珍立 《岩石学报》2018,34(1):194-206

富乐铅锌矿床位于扬子陆块西南缘的川滇黔铅锌成矿域东南部,受弥勒-师宗-水城区域性深大断裂构造控制,矿体呈似层状隐伏于中二叠统阳新组层间构造带内,赋矿围岩为白云岩。矿石矿物主要为闪锌矿,方铅矿和黄铁矿次之,含少量黄铜矿和黝铜矿等,脉石矿物主要为方解石和白云石。矿石构造主要有致密块状、浸染状和网脉状,金属矿物主要呈自形、半自形或他形粒状结构,其次为交代残余结构。已累计探明Pb+Zn金属资源量超过50万吨,平均品位大于10%Pb+Zn,最高达60%Pb+Zn,并伴随大量Cu和分散元素(如Cd、Ga、Ge等),显示其成矿环境极为特殊。本次工作通过详细的矿床地质和C-O、S及Pb同位素地球化学研究,旨在揭示该矿床的成矿物质来源及矿床成因。方解石的δ~(13)C值介于1.25‰~2.01‰之间,均值为1.64‰,与海相碳酸盐岩相似,而高于地幔和沉积有机质;δ~(18)O值为17.21‰~17.74‰,均值为17.49‰,介于海相碳酸盐岩(沉积有机质)和地幔之间。这表明方解石的C很可能来自碳酸盐岩围岩,而O同位素很可能受到流体与围岩间的水/岩相互作用影响。硫化物的δ~(34)S值介于10.04‰~16.43‰之间,均值为14.12‰,显示富集重S同位素的特征,表明成矿流体中S主要来源于沉积地层中的膏岩层,是海水硫酸盐岩热化学还原作用的产物。单颗粒方铅矿的~(206)Pb/~(204)Pb=18.5295~18.6100(均值为18.5640),~(207)Pb/~(204)Pb=15.6938~15.7024(均值为15.6974),~(208)Pb/~(204)Pb=38.5690~38.6568(均值为38.6008),其变化范围很窄,且与区域沉积岩和基底变质岩范围重叠,表明成矿金属Pb主要由沉积地层和基底岩石共同提供。综合矿床地质以及C-O、S和Pb同位素资料,本文认为富乐是一个形成于三叠纪拉张向挤压再向伸展的构造体制转换背景下、以碳酸盐岩为容矿围岩、受背斜和层间构造控制的层控、后生、富分散元素和高品位铅锌矿床,其成矿特征很可能是峨眉山岩浆作用和印支造山运动共同作用的结果。  相似文献