西昆仑卡拉牙斯卡克Pb——Zn——Cu 多金属矿床控矿构造及成矿模式     

于换涛  刘继顺  刘文恒  王天国  李曦 《世界地质》2013,32(4):733-740

运用地质与地球化学方法,对西昆仑卡拉牙斯卡克矿区控矿构造及成矿模式进行了研究。矿床地球化学测试δ34 S 为－ 5. 3‰ ～ － 32. 6‰,206 Pb /204 Pb 为17. 712 ～ 18. 082,207 Pb /204 Pb 为15. 358 ～ 15. 664,208Pb /204Pb 为37. 513 ～ 38. 399。分析显示,泥盆-石炭纪时期深部成矿物质在构造或其他动力的作用下沿区域深大断裂上涌至地表,与碎屑物质共同沉淀形成矿源层。后经主要成分为天水的流体萃取,形成含矿热液,然后在矿区构造系统中运移、富集成矿-即区域构造控制矿源层形成。矿区内低角度逆掩断层( 导矿构造) 和高角度逆冲断层及其派生的次级节理裂隙( 容矿构造) 控制矿体的形成。  相似文献   

Origins of yttrium and rare earth element distributions in metamorphic garnet   总被引：1，自引：0，他引：1  

S. J. Moore  W. D. Carlson  M. A. Hesse 《Journal of Metamorphic Geology》2013,31(6):663-689

Highly variable distributions of yttrium and rare earth elements (Y+REEs) are documented in pelitic garnet from the Picuris Mountains, New Mexico, and from Passo del Sole, Switzerland, and in mafic garnet from the Franciscan Complex, California. The wide variety of these Y+REE zoning patterns, and those described previously in other occurrences, imply diverse origins linked to differing degrees of mobility of these elements through the intergranular medium during garnet growth. In the Picuris Mountains, large, early‐nucleating crystals have radial profiles of Y+REE dominated by central peaks and annular maxima, in patterns that vary systematically with atomic number. Superimposed on these features are narrow spikes in HREEs and MREEs, located progressively rimward with decreasing atomic number. In contrast, profiles in small, late‐nucleating crystals contain only broad central maxima for all Y+REEs. In garnet from Passo del Sole, Y+REE zoning varies radically from sample to sample: in some rocks, crystals of all sizes display only central peaks for all Y+REEs; in others, profiles exhibit irregular fluctuations in Y+REE contents that match up with small‐scale patchy zoning in Y and Ca X‐ray maps. In the Franciscan Complex, Y+REE in garnet cores fluctuate unsystematically, but mantles and rims display concentric oscillatory zoning for both major elements and Y+REEs. Our interpretation of the complexity of Y+REE distributions in metamorphic garnet centres on the concept that these distributions vary primarily in response to the length scales over which these elements can equilibrate during garnet growth. Very short length scales of equilibration, due to low intergranular mobility, produce overprint zoning characterized by small‐scale irregularities. Higher but still restricted mobility yields diffusion‐controlled uptake, characterized by patterns of central peaks and annular maxima that vary with atomic number and are strongly influenced by T–t paths during garnet growth. Still greater mobility permits progressively greater, potentially rock‐wide, equilibration with major‐ and accessory‐phase assemblages, leading to mineralogical controls: an unchanging mineral assemblage during garnet growth produces bell‐shaped profiles resembling those produced by Rayleigh fractionation, whereas changes in major‐ and/or accessory‐phase assemblages produce profiles with distinct annuli and sharp discontinuities in concentration. The very high mobility associated with influxes of Y+REE‐bearing fluids can cause these element distributions to be dominated by factors external to the rock, yielding profiles characterized by abrupt shifts or oscillations that are not correlated to changes in mineral assemblages.  相似文献   

世界海底富钴结壳资源分布特征   总被引：6，自引：0，他引：6  

刘永刚  何高文  姚会强  杨永  任江波  郭丽华  梅燕雄 《矿床地质》2013,32(6):1275-1284

大洋富钴结壳资源是潜在的海底金属资源。文章对富钴结壳资源在太平洋、大西洋和印度洋分布的数据进行收集、整理、筛选、建库,从全球角度出发,对富钴结壳的分布特征进行了分析和对比。研究发现,海山、洋脊、海盆和陆坡4种地貌的Co品位分别为0.70%、0.46%、0.50%和0.43%,海山地貌更有利于高Co品位结壳的产出。三大洋中,太平洋海山富钴结壳矿点的分布比例占到了已知总数的73.3%,说明太平洋海山区是世界海底富钴结壳资源主要的产出区。根据入库数据的分布特点,在全球划分出10个富钴结壳成矿区,结合结壳的厚度和分布水深,从各成矿区中划分出富集区,并按照2 cm厚度和4 cm厚度的标准分别对富集区的富钴结壳资源量进行了估算。计算结果显示,太平洋富矿区的富钴结壳质量最好,w（Mn）、w（Co）、w（Ni）、w（Cu）平均分别为23.00%、0.66%、0.44%、0.09%,干结壳资源量分别为2426.33 Mt、70.30 Mt、48.75 Mt、10.30 Mt;按4 cm厚度指标,w（Mn）、w（Co）、w（Ni）、w（Cu）平均分别为23.70%、0.58%、0.48%、0.11%,干结壳资源量分别为1184.53 Mt、29.76 Mt、24.53 Mt、5.01 Mt。  相似文献   

Soldiers Cap Group iron‐formations,Mt Isa Inlier,Australia, as windows into the hydrothermal evolution of a base‐metal‐bearing Proterozoic rift basin     

O. J. Hatton  G. J. Davidson 《Australian Journal of Earth Sciences》2013,60(1):85-106

The Proterozoic Soldiers Cap Group, a product of two major magmatic rift phases separated by clastic sediment deposition, hosts mineralised (e.g. Pegmont Broken Hill‐type deposit) and barren iron oxide‐rich units at three main stratigraphic levels. Evaluation of detailed geological and geochemical features was carried out for one lens of an apatite‐garnet‐rich, laterally extensive (1.9 km) example, the Weatherly Creek iron‐formation, and it was placed in the context of reconnaissance studies of other similar units in the area. Chemical similarities with iron‐formations associated with Broken Hill‐type Pb–Zn deposit iron‐formations are demonstrated here. Concordant contact relationships, mineralogy, geochemical patterns and pre‐deformational alteration all indicate that the Soldiers Cap Group iron‐formations are mainly hydrothermal chemical sediments. Chondrite normalised REE patterns display positive Eu and negative Ce anomalisms, are consistent with components of both high‐temperature, reduced, hydrothermal fluid (≥250°C) and cool oxidised seawater. Major element data suggest a largely mafic provenance for montmorillonitic clays and other detritus during chemical sedimentation, consistent with westward erosion of Cover Sequence 2 volcanic rocks, rather than local mafic sources. Ni enrichment is most consistent with hydrogenous uptake by Mn‐oxides or carbonates. Temperatures inferred from REE data indicate that although they are not strongly enriched, base metals such as Pb and Zn are likely to have been transported and deposited prior to or following iron‐formation deposition. Most chemical sedimentation pre‐dated emplacement of the major mafic igneous sill complexes present in the upper part of the basin. Heating of deep basinal brines in a regional‐scale aquifer by deep‐seated mafic magma chambers is inferred to have driven development of hydrothermal fluids. Three major episodes of extension exhausted this aquifer, but were succeeded by a final climactic extensional phase, which produced widespread voluminous mafic volcanism. The lateral extent of the iron‐formations requires a depositional setting such as a sea‐floor metalliferous sediment blanket or series of brine pools, with iron‐formation deposition likely confined to much smaller fault‐fed areas surrounded by Fe–Mn–P–anomalous sediments. These relationships indicate that in such settings, major sulfide deposits and their associated chemical sediment marker horizons need not overlie major igneous sequences. Rather, the timing of expulsion of hydrothermal fluid reflects the interplay between deep‐seated heating, extension and magmatism.  相似文献   

Discussion and Reply Lithostratigraphic revision and correlation of the Oligo‐Miocene Murray Supergroup,western Murray Basin,South Australia     

P. A. Rogers  J. J. Lukasik  N. P. James 《Australian Journal of Earth Sciences》2013,60(3):485-486

Sequence‐stratigraphic interpretations of the 4200 m‐thick Palaeoproterozoic (1700–1650 Ma) Mt Isa Group and underlying Surprise Creek Formation identify three unconformity‐bounded packages termed the Prize, Gun and Loretta Supersequences. Siliciclastic rocks of the Surprise Creek Formation and Warrina Park Quartzite comprise the Prize Supersequence. Rapid facies changes from proximal, conglomeratic fluvial packages to distal, fine‐grained and deep‐water, rhythmites characterise this supersequence. Conglomeratic intervals in the Mt Isa area reflect syndepositional movement along basin‐margin faults during the period of supersequence initiation. A major unconformity, which extends over a period of about 25 million years, separates the Gun and Prize Supersequences. In the Leichhardt River Fault Trough uplift and incision of Prize sedimentary rocks coincided with emplacement of the Sybella Granite (1671±8 Ma) and Carters Bore Rhyolite (1678±2 Ma) and the removal of an unknown thickness of Prize Supersequence section. Deep‐water, turbiditic rhythmites of the Mt Isa Group dominated the Gun and Loretta Supersequences. Tempestites are present over discrete intervals and represent times of relative shallowing. High accommodation and sedimentation rates at the base of the Gun Supersequence resulted in the deposition of transgressive nearshore facies (uppermost Warrina Park Quartzite) overlain by a thick interval of deep‐water, siltstone‐mudstone rhythmites of the Moondarra Siltstone and Breakaway Shale. With declining rates of siliciclastic sedimentation and shallowing of the succession, calcareous sediments of the Native Bee Siltstone prograded over the deeper water deposits. Two third‐order sequences, Gun 1 and 2, characterise these lower parts of the Gun Supersequence. An increase in accommodation rates near the top of the Native Bee Siltstone in Gun 3 time, resulted in a return to deep‐water sedimentation with deposition of dolomitic rhythmites of the Urquhart Shale and Spear Siltstone. The Pb–Zn–Ag ore‐hosting interval of the Urquhart Shale is interpreted to occur in progradational highstand deposits of the Gun 3 Sequence. In the Leichhardt River Fault Trough the Loretta Supersequence boundary forms a correlative conformity. Coarser grained and thicker bedded sediments of the Kennedy Siltstone comprise lowstand deposits at the base of this cycle. These sediments fine up into the transgressive, deep‐water, siliciclastic facies of the Magazine Shale, which in turn are truncated against the Mt Isa Fault.  相似文献   

Heavy-metal loadings related to urban contamination in the Kooloonbung Creek catchment,Port Macquarie,New South Wales     

P. M. Ashley  M. E. Napier 《Australian Journal of Earth Sciences》2013,60(6):843-862

Urbanisation and industrial development lead to contamination of estuaries and streams with dispersed loadings of heavy metals and metalloids. Contributions of these elements also occur from natural sources. This study provides baseline geochemical data on the respective natural and anthropogenic inputs of Cu, Pb, Zn, Cd, As, Sb, Cr, Ni, Mn and S to estuarine, fluvial and wetland sediments, and adjacent soils, in the Kooloonbung Creek catchment that drains the Port Macquarie urban area in north coastal New South Wales. There have been anthropogenic additions of Cu, Pb, Zn and As from dispersed urban sources at Port Macquarie, but they are restricted to the local catchment and do not impact on the adjacent Hastings River estuary. The most contaminated sediments display enrichment factors up to 20 × for Cu and Pb, 9 × for Zn and 5 × for As relative to local background values. However, only one value (for Pb) exceeds National Water Quality Management Strategy interim sediment quality guideline (high) values. On the other hand, sediments and local soils are commonly strongly enriched in Cr, Ni and Mn, reflecting adjacent ultramafic and mafic rock substrate and lateritic regolith. Concentrations of Cr and Ni are commonly well above interim sediment quality guideline (high) values for sediments, but are in mineralogical forms that are not readily bioavailable. Sediment and soil quality guideline values consequently need to recognise natural enrichments and the mineralogical siting of heavy metals. Although dissolved concentrations of heavy metals in stream waters are commonly low, there is evidence for mobility of Cu, Zn, Fe and Al. Parts of the Kooloonbung Creek wetland area lie on sulfidic estuarine sediments (potential acid sulfate soils). Experimental oxidation of uncontaminated and contaminated sulfidic sediments leads to substantial dissolution of heavy metals under acid conditions, with subsequent aquatic mobility. The results warn about disturbance and oxidation of potential acid sulfate soils that have been contaminated by urban and natural heavy-metal sources.  相似文献   

德兴铜矿地区土壤的基本特征及其对重金属元素的吸附研究     

李子悦  吴沣  郝瑞霞 《岩石矿物学杂志》2013,32(6):1013-1021

本文首先分析了江西德兴铜矿区周围土壤的微量元素和矿物组成特征,结果显示该地区重金属元素富集,且表层土中重金属元素含量与粘土矿物相对含量变化具有较好的一致性。室内土柱淋滤实验结果表明,当总淋滤时间为451 h时,土壤对Pb²⁺的总吸附量为2 584.75 mg/kg,淋滤实验的前半期存在多种竞争吸附机制,后半期土壤对Pb²⁺的吸附基本达到动态平衡。淋滤后土壤矿物的相对质量分数发生了改变,粘土矿物有所减少。粘土矿物在不同土壤层对Pb²⁺的吸附能力也各异。  相似文献   

岩溶型尾矿库渗滤液重金属污染防治技术研究进展     

肖筱瑜  李蘅  张静  徐文炘 《矿产与地质》2013,(2):173-176

文章通过对岩溶型尾矿库渗滤液重金属污染防治技术相关方法进行研究,结果表明可渗透反应墙(PRB)处理污染地下水具有初期建设投资低、可以根据所要处理的污染物质灵活选择、运行期不需要能量供给而且处理设施不会占用宝贵的土地资源等显著优点,是岩溶型尾矿渗滤液治理方面最具发展前景的方法之一。  相似文献   

Ultrasound‐Assisted Emulsification–Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry for the Determination of Trace Lead in Water     

Hongmei Jiang  Yu Zhang  Bocheng Qiu  Wenhua Li 《洁净——土壤、空气、水》2012,40(4):438-443

The ultrasound‐assisted emulsification–microextraction (USAEME) method was combined with graphite furnace atomic absorption spectrometry (GFAAS) for the determination of trace Pb using dithizone (H²DZ) as chelating reagent. Some effective parameters influenced the detection and microextraction, such as ashing temperature and atomization temperature, pH, extraction solvent, sample volume, extraction time, and extraction temperature were selected and optimized. After extraction, the calibration curves for Pb was in the concentration range of 0.1–10 ng mL^?1, and the linear equation was y = 0.097 x + 0.023 (R = 0.99). Under the optimized conditions, the detection limit of the method was 20 pg mL^?1 with an enrichment factor of 70 and the relative standards deviation (RSD) for seven determinations of 1 ng mL^?1 Pb was 11%. The proposed method was successfully applied to determine trace Pb in Yueya Lake water, pond water, and spiked samples. Furthermore, a certified reference material of Environment Water (GBW08607) was analyzed and the determined value was in good agreement with the certified value, which showed the accuracy, recovery, and applicability of the reported method.  相似文献   

基于精密探测的金属矿山采空区群稳定性分析     

宋卫东  付建新  杜建华  张朝雷 《岩土力学》2012,33(12):3781-3787

采空区群的稳定性分析是一个复杂的地质问题,而在区域内存在一种群效应。准确地掌握采空区群的三维形态和空间的相对位置是进行稳定性分析的前提。以石人沟铁矿为背景,利用空区探测系统（CMS）对采空区进行了精密探测,并对探测数据进行处理和转换,在此基础上,应用3Dmine建立了采空区群的三维空间模型,经过进一步处理实现了与FLAC3D的耦合,建立了三维数值计算模型。根据计算结果对采空区群区域的应力场、位移场进行了分析,对群区域内的群效应进行了阐述。在此基础上对群区域地表位移进行了分析,确定了地表最大位移面积和采空区水平面积的比值。研究结果表明,区域内的群效应使应力和位移较单个采空区时都有了较大增加,且增加幅度并不是单纯的叠加,这种效应加剧了采空区的危险等级,将CMS、3Dmine和FLAC3D三者的优势结合起来,为采空区群得稳定性分析提供了一个准确而有效的途径。  相似文献