THE APPLICATION OF REMOTE SENSING TECHNIQUE ON GEOLOGICAL INVESTIGATION OF PLACER DEPOSIT     

万恩璞  溥立群  王野乔  陈春  刘殿伟 《中国地理科学(英文版)》1991,1(2):166-178

The practice has proved that it is an economic and effective method to investigate placer gold deposit by using multi-level information sources of remote sensing and multi-variate analysis methods, especially for the area with a sparse population and difficult condition like the Da Hinggan Mountains, China.The information sources used in our work includes Landsat TM, aerial infrared photography and their mosaic image maps and enlarged photos with different scales. According to statistic data, in the study area the gold-bearing rocks are mainly granite, alaskite, granodiorite and some old metamorphic rocks. On gold-bearing geological structures, the fault zones in the four directions (NE, NNE, NW and EW) are obvious, in which NNE and EW are the most key fault zones. On fluvial geomorphology the flow courses stored placer are in the tributaries of the 4th and 5th levels, especially in straight or slight curve reaches. On the basis of analysis the interpretative signs were set up, and the interpretative wo  相似文献   

Evolution of deep‐lead palaeodrainages and gold exploration at Ballarat,Australia     

D. H. Taylor  L. V. Gentle 《Australian Journal of Earth Sciences》2013,60(5):869-878

Ballarat in western Victoria hosts substantial hard‐rock and palaeoplacer gold deposits. The most famous placers are the deep leads—channel deposits of a middle Cenozoic drainage system that were buried by voluminous basalt flows over the past few million years. The basalt has also shielded large areas of the highly prospective bedrock from exploration for more of the hard‐rock gold deposits. Although difficult to explore for, such deposits could express themselves as geochemical plumes in the major aquifer system hosted by the deep leads. Groundwater sampling may provide a vector to such deposits, but around Ballarat debate has long surrounded the distribution and flow directions of the deep leads, which are critical for this exploration methodology. The present landscape around Ballarat began to develop in the Early Cenozoic when a pre‐existing Mesozoic landscape was severely dissected during Australia‐Antarctica breakup. Several cycles of erosion left several generations of fluvial placer deposits scattered across the present landscape. New data from regional mapping, boreholes and compilation of historical records elucidates the positions and flow directions of the deep leads. The distribution and flow directions of the deep leads beneath the basalt are different to, and cannot be inferred from, the present drainage upon the basalt. The deep‐lead drainage divide runs beneath the city of Ballarat with divergence of up to 30 km between the deep lead and the present drainage divides. The divide was shifted northward to its present position by the process of drainage diversion because the basalt eruptions built new topography to greater heights than along the pre‐existing deep‐lead divide.  相似文献   

Provenance Signature of Pre-Cambrian and Mesozoic Rocks in the Nearshore Placers of Konkan,Central West Coast of India     

A. R. Gujar  N. Angusamy  G. V. Rajamanickam 《Marine Georesources & Geotechnology》2013,31(2):115-131

Heavy mineral studies of the nearshore placer deposits of the Konkan Coast reveal a dominant assemblage comprised of garnet and kyanite along with other accessory minerals like epidote, olivine and rutile. The heavy mineral assemblage of the study region shows a characteristic suite of 17 types of heavy minerals. Their abundance shows hardly any drastic variation in the four bays studied. Overwhelming presence of minerals like garnet and kyanite in the studied four bays points to the source as metamorphic rocks. The presence of etched garnets, overgrown zircons and etched kyanites corroborate the recycling of paleo-sediments into the bay. Characterization of opaques under the microscope also corroborates the influence of a metamorphic source, rather than the adjoining basaltic rocks. However, the absence of metamorphic rocks in the hinterland suggests the possibility of deposition of sediments predominantly from offshore. Factor analysis results also corroborate the overwhelming influence of metamorphic rocks in the present study region rather than the abutting basalts.  相似文献   

辽宁省南部金刚石分布及找矿预测     

张树林  郭阳春  吴德军 《吉林地质》2009,28(2):60-63

详细地介绍了辽宁省南部发现的金伯利岩岩体和金刚石砂矿形成地质条件、分布范围,特别是金刚石砂矿成因类型、分布规律及成矿远景区预测。  相似文献   

Colloform high-purity platinum from the placer deposit of Koura River (Gornaya Shoriya,Russia)     

《Ore Geology Reviews》2017

A microinclusion of colloform high-purity platinum in a grain of platinum-group minerals (PGM) from the alluvial gold-bearing placer deposit in the south of Western Siberia (Russia) was detected and characterized for the first time. It is different in composition, texture, and conditions of formation from high-purity platinum of other regions described in the literature. The main characteristics of investigated high-purity platinum are colloform-layered texture, admixture of Fe (0.37–0.78 wt%), and paragenesis of Cu-rich isoferroplatinum, hongshiite, and rhodarsenide. The PGM grain with high-purity platinum is multiphase and heterogeneous in texture. It is a product of intensive metasomatic transformation of Cu-rich isoferroplatinum (Pt₃(Fe_0.6Cu_0.4)). The transformation was carried out in two stages: 1 – copper stage including three substages (Cu-rich isoferroplatinum, copper platinum and hongshiite); and 2 – arsenic (rhodarsenide). The formation of high-purity platinum was separated in time from the formation of isoferroplatinum and was carried out by precipitation from postmagmatic solutions.  相似文献   

Study on Seed Bank Composition and Seedling Emergence Regularity in Placer Iron Ore Soil     

HOU Yurong  KE Mei  WEI Peng  LAN Jiyong  LI Chao  KANG Shuai  KAYRAT Aldeyarhan  WANG Lu 《资源与生态学报(英文版)》2022,13(2):312-318

The mining of placer iron ore greatly influences the surrounding desert grassland. In Agdala Town, Qinghe County, Xinjiang, the soil seed bank is severely damaged, and the utilization and productivity of desert grasslands are almost zero, which seriously affects the safety of the ecological environment and the development of local animal husbandry. It is very important to supplement soil seed banks to enhance the species composition of desert grasslands after ecological restoration. In this study, the effects of the seed bank, species composition, and seed burial depth on the seedling emergence rate at placer iron ore site before and after artificial seed bank replenishment were compared using the germination tray method. The original soil seed bank in the study area contained only four species, which were all annual plants. The dominant species were Salsola ruthenica and Corispermum orientale, and the soil seed bank density was very small. The emergence regularity of the soil seed bank was closely related to water content, and the emergence of annual vegetation was explosive. Seed burial depth affected the emergence rate of perennial grass, and we determined that a burial depth of 0-5 cm was the most effective for emergence. This indicates that seedling emergence of artificially supplemented soil seed bank can be completed within 7 days if the sowing depth is appropriate; sowing depths greater than 5 cm affect seed germination. These findings provide a basis for selecting species to populate large areas.  相似文献   

Differential Alteration of Ilmenite in a Tropical Beach Placer, Southern India: Microscopic and Electron Probe Evidences     

Ajith G. Nair    D. S. Suresh  Babu  K. L.Vivekanandan  Silvio R. F. Vlach 《Resource Geology》2006,56(1):75-81

Abstract. The study based on microscopic and microprobe techniques reveals that ilmenite of Manavalakurichi deposit has generally reached the alteration phase of 'leached ilmenite'. The XRD and bulk chemical analysis confirm the limited alteration undergone by ilmenite grains. Ilmenite alteration has been found to be a process of continuous leaching of iron from the mineral lattice and hydroxylisation. The enrichment of trace elements with progressive alteration is discussed. Si and Al are enriched by more than 100 fold. The prevalence of reducing environment at present in the deposit indicates that the oxidation of ferrous iron leading to pseudorutile formation would have occurred during transportation of sediments.  相似文献   

秘鲁朋友砂金矿床成矿模型研究     

刘显沐 《矿产与地质》2005,19(5):495-500

朋友砂金矿床位于秘鲁南部亚马逊盆地中,具有典型的热带雨林气候和独特的水文地质特征.第四系松散堆积层发育完全,厚度大.圣母河砂金矿的富集有明显规律性,其与水文地质条件及物质来源相关,这种成矿规律性可用一模型来描述,该模型适用于具有金矿成矿物质来源的热带河流冲积型砂金矿床.合理的找矿方法是热带雨林地区砂金矿床定位评价的关键.  相似文献   

基于GIS的重矿物空间分布特征及原生矿耦合关系研究     

庄毓敏  刘晓洁  杨正萌 《吉林地质》2004,23(4):126-131

在吉林省重砂数据库的基础上,利用地理信息系统对延吉市幅及通化重砂数据进行空间分析,建立数据模型,利用重矿物的数据结构特征与已知金矿床进行的耦合关系研究发现,金矿形成普遍分析在D>2.0,均在二级预测区,斑块变形指数和斑块面积与含金量相关,大则含金量高。  相似文献   

贵州锦屏隆里-黎平平地   总被引：1，自引：2，他引：1  

秦守荣  易国贵  罗晋辉 《贵州地质》2001,18(3):145-148

锦屏隆里－黎平平地一带的辉石重砂异常，异常矿物为辉石、铬铁矿及钛磁铁矿。总面积约200km^2。位置与贵州地矿局101地质队一个寻找金刚石矿床的靶区大略相符。其重要意义是拓展了贵州可能存在基－超基性侵入岩体的分布地区，若经检查验证，可望发现新的基一超基性小岩体，甚至原生金刚石矿床。  相似文献