岩屑测量在甘肃北山水系沉积物测量弱异常区的找矿效果:以盐池黑山南金矿的发现为例

研究区地球化学景观属于甘肃北山干旱荒漠戈壁残山区,通过1∶2.5万水系沉积物测量在北山盐池黑山一带圈定多处金弱异常。为突出成矿及指示元素的地球化学异常特征,提高找矿效果,优选水系沉积物测量金弱异常,开展1∶1万岩屑测量,利用相关性及R型聚类分析对元素组合特征进行分析、归纳,并圈定单元素异常和综合异常。对成矿前景较好的2处综合异常,采用踏勘追索、大比例尺地质填图及探槽等手段进行查证,发现了盐池黑山南金矿,实现了在水系沉积物弱异常区的找矿突破,研究成果充分证实岩屑测量在甘肃北山干旱荒漠戈壁残山区进行地质找矿的有效性,为北山水系沉积物测量弱异常区找矿提供了新的途径。     

北祁连中段浪力克—牛头山一带地球化学特征

近年来,部署在重要成矿区带的1：5万区域矿产调查在全国陆续展开,这对提高地质矿产研究程度,进一步圈定找矿靶区具有重要意义。其中要求进行1：5万水系沉积物测量、高精度地面磁测、自然重砂测量和遥感异常提取。本文以甘青交界的浪力克一牛头山一带1：5万区域矿产调查中水系沉积物测量实际资料为依据,探讨了浪力克铜矿区及其区域地球化学特征,认为Cu、Pb、Zn、Au、Ag异常分布与含铜火山岩系分布一致,异常规模显示该矿外围仍具有较大的找矿潜力。     

重砂化学测量是一种有效的找矿方法

传统的河流重砂，以及水系沉积物、土壤测量和水地球化学等找矿方法，是早已熟知和公认的有效找矿手段。但重砂化学测量找矿法，在我国大概还解为人知。据报道，美国在60年代已开始研究，至80年代已较为普遍推广。     

1:20万区域化探方法核心技术"取样粒级"的讨论

内蒙古区域化探扫面采用水系沉积物测量(或土壤测量),取粗粒级样品,取得了较好的地质找矿效果,但局部景观区找矿效果受到了一些影响.我国南北方水系沉积物中元素含量呈"U"形分布,反映了南北方不同的风化类型,以及所取不同粒级样品的物质成分也不同;取粗粒级和细粒级样品均可能有化探异常显示,采用-5～+20目(0.9 mm≤A＜4 mm)和-120目(A＜-0.125 mm)组合粒级作为采样粒级.为提高工效,取样时可以采用-5目(或-20目)全粒级物质,也能获取更多的找矿信息.这种取样粒级技术,也适宜于全国各种不同的景观区的不同尺度的水系沉积物测量和土壤测量的化探工作.     

1:25000沟系沉积物地球化学测量方法有效性探讨——以东昆仑巴隆地区为例

青海东昆仑地区是青海省重要的金、铜、铁多金属成矿区,1∶250 000、1∶50 000水系沉积物地球化学测量工作在该区域圈定了众多的异常区,但总体查证程度偏低。为实现该区域找矿重大突破,选定巴隆地区部署开展了以采集水系沉积物为主、残坡积岩屑物质为辅的1∶25 000沟系沉积物地球化学测量工作,取得了较为突出的找矿效果。该项工作表明,在青海省东昆仑地区,1∶25 000沟系沉积物地球化学测量方法是一种有效的地质找矿工作手段。该方法能有效克服东昆仑地区北部水系不发育、风成物干扰严重,南部高山区碎石流发育、影响水系沉积物汇聚等因素对找矿的干扰,相对传统的地质找矿方法在异常查证过程中的适用性、可操作性更强,找矿效果好,能实现矿体的精确定位,对东昆仑的地质找矿工作具有借鉴作用。     

地球化学勘查在黑龙江省陆角岭区地质找矿中的应用

森林沼泽景观区1:5万水系沉积物地球化学测量是在森林沼泽区进行地球化学勘查的重要方法之一,在陆角岭工作区,应用水系沉积物测量、土壤测量查证工作,找矿效果显著.     

青海立新地区水系沉积物地球化学特征及找矿预测

根据1∶5万水系沉积物测量分析结果,研究了青海立新地区水系沉积物地球化学特征。通过对元素的含量、元素的相关性、元素异常组合等特征的研究,结果显示地球化学水系沉积物测量在圈定找矿远景区上有较好的找矿效果,在此基础上结合区内地质成矿构造条件,优选了拉忍科钨铋多金属矿、多香琼陇铅铋多金属矿和巴陇斜尼金多金属矿3处找矿靶区。     

用地球化学异常图和方差分析比较两种采样粒级的化探效果

化探新方法在森林沼泽区域的使用,进一步拓展了区域化探资料的应用范围,使其在基础地质调查中的应用成为可能.森林覆盖区水系沉积物中,有机质含量较高,选择较粗粒级水系沉积物,可有效排除有机质的影响.以黑龙江大兴安岭某地水系沉积物测量为例,选择2种不同的粒级(-10～+40目、-10～+60目)的水系沉积物测量结果进行对比研究,应用地球化学异常图解和方差分析的方法来比较各自的找矿效果.研究结果表明,这2种粒级的化探找矿效果无实质性差异.     

福建街面—水口地区水系沉积物地球化学特征及找矿方向

通过开展福建街面—水口地区1:5万水系沉积物测量工作,获得了较丰富的水系沉积物地球化学测量成果。对水系沉积物18种元素总体含量和在不同地质单元中的含量特征进行了统计分析,明确了成矿有利期和主要成矿元素。根据元素异常分布规律结合成矿地质条件、已有矿床(点)划分了找矿远景区,明确了研究区找矿方向。     

湖南禾库地区水系沉积物地球化学特征及找矿预测

依据1∶5万水系沉积物测量资料,分析研究了湖南禾库地区水系沉积物地球化学特征。对元素分布、单元素异常、元素相关性、异常元素组合等特征的研究表明水系沉积物地球化学测量方法在高山峻岭、地形复杂的禾库地区有良好的找矿效果,并优选了嗅脑和杉木冲2处铅锌找矿远景区。     

A contribution to geochemical prospecting for fluorite

With fluorine as indicator, eight different extraction methods were tested for their suitability in geochemical prospecting for fluorite in stream sediments. Since this material can be regarded as coarse-grained, clastic fragments derived from the bedrock - i.e. granites, gneisses, and fluorite veins as well - it was concluded that the fluorine content of the stream sediments comes mostly from fluorine-bearing bedrock minerals. Anomalous samples contain fluorine predominantly as fluorite from fluorspar mineralization.Five of the commonest fluorine-bearing minerals - fluorite, mica, apatite, amphibole and tourmaline - were treated with the different extractants and with various times of reaction and mineral grain size. Fluorine analysis was by ion-selective electrode. The ratio cx-F (fluorite) vs. cx-F (mica, apatite) was found to be a useful measure of the applicability of the respective method.In order to test this conclusion 41 stream sediment samples (−177 microns −80 mesh) from the area under investigation were treated with eight different extractants.The most suitable extraction solution - boric acid solution - was used for the reconnaissance stream sediment survey in an area of 400 km² in the southeastern part of the Black Forest (F.R. Germany).     

Quantitative determination of cerussite (lead carbonate) by X-ray powder diffraction and inferences for lead speciation and transport in stream sediments from a former lead mining area in Scotland

Most current investigations of sites contaminated with heavy metals (e.g. Pb, Zn, Cu) emphasise the importance of determining the amounts of physical and chemical forms of metals rather than just the total amounts present. Chemical extraction techniques used for this purpose are inevitably operationally defined. A more direct approach to the identification of crystalline forms can be made by mineralogical techniques such as X-ray powder diffraction (XRPD), but quantitative determination of a particular form is not often attempted. Recent advances in methods of analysis and sample preparation for XRPD mean that it is now a relatively simple matter to obtain quantitative XRPD data. Here, it is applied to the quantitative determination of the forms of Pb in different size-fractions of stream sediment samples from Leadhills/Wanlockhead, SW Scotland, an historic Pb mining area. Comparison of the XRPD analyses with determinations of Pb by atomic absorption spectrophotometry demonstrates that a large proportion of the Pb present in the stream sediments is in the form of cerussite (PbCO₃). Furthermore, the cerussite tends to be concentrated in the silt fraction and is even a minor component of the clay-size fraction. However, quantitative analysis of fractions <6 μm indicates that cerussite alone cannot account for all the Pb in this size range. Indirectly, this result suggests that Pb adsorbed to clay minerals, organic matter and/or amorphous Fe and Mn oxides may be proportionally more important for the <6 μm materials. Sediment in this size range, however, typically accounts for no more than 1% by weight of the total stream bed sediment samples collected in the study area. In relation to its size distribution, the mobility of Pb within the wider environment is most likely to occur principally through physical transport of fine particles.     

吉南玄武岩覆盖区水化学异常查证──以两处金矿化的发现为例

本文通过实例,介绍了吉南玄武岩覆盖区水化学异常查证的化探工作方法。综合研究已有地质条件,认为吉南沿江村、马鹿沟水化学异常地区成矿地质条件有利。结合微景观特点,在沿江异常区2km²范围内应用汞气测量圈出区内断裂构造带展布方向。岩石剖面、土壤测量显示出构造经历过热液矿化活动,矿化体埋藏较深。根据土壤测量结果优选出验证靶区。钻探验证结果在地表620m以下发现了近30m厚的Au矿化体,Au含量最高1.5g/t.马鹿沟水化学异常区使用水系沉积物测量进行异常追踪,迅速缩小了找矿“靶区”.使用重矿物测量在“靶区”内进一步追踪发现了Au矿化源。在此基础上经大比例尺土壤测量辅以岩石剖面测量,圈出了一个有望找到火山岩型浅成热液金矿床的成矿远景区。     

西藏冈底斯东段铜多金属成矿带综合物化探技术有效性试验

应用综合物化探方法在西藏冈底斯东段铜多金属成矿带驱龙、甲马矿区进行了方法有效性试验。介绍了野外方法试验采用的综合物化探技术及数据处理方法,对各方法的试验成果进行了综合对比分析,在此基础上展望了以DPEM、TEM方法为主的综合物化探方法在该区矿产资源勘查评价中的巨大应用潜力。     

PGE exploration in the Wadi Amarah complex,southwestern Arabian Shield

A stream sediment survey targeting PGE and their pathfinders was carried out at a gabbro/pyroxenite complex in Wadi Amarah in the SW Arabian Shield. Twenty-nine stream sediment samples were collected from wadi channels and analyzed for PGE and base metals. None of the samples contained detectable PGE except for WAS-3 and WAS-27 which returned values above 70 ppb of combined Pt and Pd; these two locations are also anomalous for Au. A follow-up survey was conducted to further investigate the anomalies at these locations. A total of 48 soil and rock samples were collected from the two anomalous localities. Unlike the initial survey, most samples contained detectable PGE and Au albeit not as high as the original anomalies. Factor analysis of the results from the initial survey returned five main factors, with the first four reflecting the effects of mineral detritus as well as adsorption onto Fe–Mn oxyhydroxides; however, the last factor is loaded only for Cu and Ni and is therefore considered an ore factor indicating the presence of Cu–Ni sulphides. Another five factors were obtained from the follow-up survey, and as was the case in the initial survey, the first four factors are detrital/adsorption-related, while factor 5 has high loadings for only Pd and Pt and is therefore interpreted as a PGE ore factor. These findings reveal different modes of dispersion of PGE and base metals in the secondary environment and, more importantly, demonstrate the effectiveness of factor analysis in detecting even faint anomalies from disseminated mineralization.     

Geochemical survey of rare earth elements (REEs) in the concealed ore body of Hongcheon,Korea

Because of the risk of diminishing supplies of rare earth elements (REEs) worldwide due to China’s dominance over REE supply, the necessity of developing domestic resources of REE has been realized in other countries. To explore new ore bodies, a geochemical survey was conducted at one existing carbonatite REE deposit in the Hongcheon area of Korea. Proper sampling strategies and baseline data for the interpretation of the results were determined through a pilot study conducted in the area. Enrichment in the concentration of light REE (LREE) over that of heavy REE, which is typical in carbonatite-type deposits, was observed in stream sediments and heavy mineral samples collected during the geochemical survey. Maximum concentrations of LREE were 2,299 and 27,798 mg/kg for stream sediments and heavy minerals, respectively. Among LREEs, La and Ce are the dominant components of all REEs, comprising approximately 68 % of mean concentrations. Considering the distribution pattern of La + Ce contents and the associations with the existing outcropping ore bodies, the zone of prospective REE mineralization was determined to be in the south-western part of the area. A detailed follow-up soil survey of the zone found even higher concentrations of La and Ce (2,450 and 3,100 mg/kg, respectively), and suggested the possible extension of the existing ore bodies. Likewise, a systematic geochemical survey for REE is feasible for locating concealed ore bodies in the area, where the mineralization is mostly covered with soil, and rock outcrops are scarce.     

非传统化探方法研究的新进展

在20世纪的找矿实践中,水系沉积物、土壤和岩石地球化学测量等传统化探方法发挥了令矿产资源勘查界瞩目的重要作用。随着深部找矿,特别是覆盖区找矿工作的日益增多,传统化探方法已不完全适应这种找矿条件,急需有新的方法技术予以补充。20世纪诞生的一套非传统化探方法,如选择性提取法、生物地球化学测量、地下水地球化学测量、地下气体测量等,重又受到青睐。在现代化学分析技术的支撑下,选择性提取技术成为当前化探界研究的热点,试点性研究显示了其找寻隐伏矿的有效性;生物地球化学找矿方法在植物积累元素的控制条件、分析测试方面均取得了较大进展,已经从幼年期进入成熟的早期阶段;地下水地球化学测量方法在地下水中矿物饱和度与物质计算、高质量的物理化学数据的获取和不同矿床类型的元素化合物指示标志的研究与评价方面做了大量的工作。同时,数据处理技术、重矿物地球化学找矿标志和同位素地球化学示踪技术的研究近年来也受到了极大关注。实验性研究表明,尽管这些非传统技术在找寻隐伏矿方面显示了良好的应用前景,但仍有许多问题需要深入研究。     

遥感在大兴安岭森林覆盖区地质矿产调查中的应用——以黑龙江洛古河1:5万区域地质矿产调查工作为例

大兴安岭地区森林覆盖严重, 气候严寒, 交通极为不便, 野外有效工作时间短, 给区域地质矿产调查工作增加了难度, 急需遥感手段提高成果质量和效率. 在黑龙江大兴安岭洛古河等4幅1:5万区域地质矿产调查工作中, 利用SPOT7、Landsat7/8、ASTER等多种遥感数据开展地质矿产解译, 进行遥感影像分区, 建立地层、构造和侵入岩解译标志, 提取羟基和铁染蚀变异常, 结合水系沉积物测量成果划分了成矿有利区, 有效降低了地质矿产调查强度, 提高了调查效率, 增强了调查质量. 表明遥感技术在大兴安岭高植被覆盖区地质矿产调查过程中能够取得较好效果.     

重矿物分析识别浊积体的沉积作用——日本中部Niigata弧后含油盆地新第三纪浊积砂岩实例研究(英文)

沉积于中中新世到上新世的浊积砂体是第三纪Niigata弧后盆地的主要油气储层之一 ,该盆地是日本列岛最富产石油的盆地。我们对这些浊积砂体的重矿物进行了详细和系统地分析。首先 ,作者展示了将重矿物分析和沉积作用分析相结合 ,从而得出有关沉积过程的全新观点的实例。沿着位于盆地东缘的上新世早期的浊积砂岩体的垂向和横向取样分析表明 ,砂体东半部重矿物的成分和西半部重矿物的成分不同。重矿物和沉积分析结果表明 ,发育在东半部的浅海陆架浊积砂岩和发育在西半部的深海水下浊积体在上新世早期是相互叠置的。其次 ,作者检验了用重矿物成分作为指标来表征某个特定浊积体的有效性。为此目的特选重位于Ni igata盆地中部的许多浊积砂岩分析研究 ,得出以下结论。 ( 1)基于主要重矿物 ,比如蛋白石、普通角闪石、紫苏辉石和普通辉石的定量综合分析 ,至少可将研究区的浊积砂岩划分为 6种类型 ;( 2 )一个组或段的浊积砂岩包括一种类型或紧密相关的两种类型 ;( 3)研究区不同的组或段通常由不同的重矿物组成构成 ,不同的物源或相同物源下不同的地质事件 (例如火山活动开始期 )可能是这种差异的原因。重矿物分析不仅可作为有价值的常规手段估计物源方向 ,而且可同其他的沉积资料结合来解析沉积过程 ,估计几个相邻