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951.
山西柳林泉域地下水化学信息的因子—克立格分析 总被引:2,自引:0,他引:2
本文尝试将因子分析与克立格法相结合,用以分析柳林泉域地下水化学资料,获取到地下水成因,循环深度等方面的信息。研究表明,因子-克立格法是一种有效,实用的研究区域水文地质问题的分析方法。 相似文献
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Abstract: The Bidjovagge gold-copper deposit, northern Norway occurs in the lower Proterozoic Kautokeino greenstone belt, and consists of ten ore bodies in albite felsite, graphite schist and meta-diabase sills, along with a series of syenodiorite dykes. Calcite is one of the most important gangue minerals occurring within the ore veins. The early primary calcite samples from A, C and D ore bodies (copper–rich) show almost flat chondrite-normalised REE curves, and slightly positive Eu anomalies. A Sm-Nd isotope age of 1858 ± 72 Ma (2ρ) has been given based on fifteen primary calcite samples. The Sm-Nd age of calcite is in well agreement with previously published U-Pb davidite age of 1885 ±18 Ma (2ρ) and Sm-Nd davidite age of 1886 ± 88 Ma (2ρ). All these isotopic age data indicate that the gold-copper mineralisation may occur during or slightly after the peak of the Svecokarelian orogeny. Two late primary calcite samples from C and D ore bodies have flat chondrite-normalised LREE curves, positive HREE curves, and negative Eu anomalies. In contrast, most of the early primary calcite samples from B ore body (gold–rich) show an overall negative chondrite-normalised REE slope and negative Eu anomalies. Sm-Nd data on seven primary calcite samples from the B ore body are relatively scattered, and gave an isochrone age of 1809 ± 150 Ma (2ρ), identical to the age of the calcite samples from A, C and D ore bodies. Two late primary calcite samples from the B ore body have almost flat chondrite-normalised REE slope and negative Eu anomalies. REE patterns and eNd (T) values of calcites suggest that the ore fluids for the calcites from the A, C and D ore bodies derived their metals from mafic igneous rocks (diabase sills). For the secondary calcites from the C ore body, their relative high initial Nd (T) values at 1858 Ma imply that much more radiogenic Nd-component were incorporated during calcite crystallisation when another ore fluid emplaced. Combined Nd isotope data and REE geochemical features suggest that the isotopically more evolved source such as albite felsite and syn-genetic high level syenodiorite dykes were probably metal source for these calcites in the B ore body. Three samples of secondary calcite from the B ore body, which obviously deviated from 1809 Ma isochron are easily explained as products of post-ore hydrothermal events. 相似文献
955.
近来南岭地区加里东期钨锡找矿勘查取得较大突破,但其成因机制研究仍相对缺乏。湘西南苗儿山岩体西北部的落家冲矿床是近年新发现的加里东期钨锡矿床,具有良好的钨锡多金属矿找矿前景,其成矿流体的特征和成矿机制有待查明。在详细的野外地质调查基础上,落家冲矿床的成矿过程可划分为四个阶段:蚀变花岗岩-白钨矿阶段(Ⅰ)、云英岩-白钨矿-锡石阶段(Ⅱ)、石英脉-白钨矿阶段(Ⅲ)和石英脉-硫化物阶段(Ⅳ)。本文选取第Ⅰ阶段的锆石和锡石开展了U-Pb定年和锆石Hf同位素分析,对四个成矿阶段的石英矿物进行了流体包裹体以及H-O同位素的研究。获得的锡石U-Pb反等时线年龄(433.0±11Ma)与蚀变花岗岩锆石U-Pb年龄(430.7±2.3Ma)在误差范围内一致,表明矿区的成岩成矿作用均发生于加里东晚期。流体包裹体研究显示第Ⅰ阶段到第Ⅳ阶段,均一温度分别集中在260-380℃、260-320℃、200-320℃和180-220℃之间,呈逐渐降低的趋势,盐度则表现为由第Ⅰ阶段到第Ⅱ阶段陡降,第Ⅱ阶段到第Ⅳ阶段总体变化不大的特点(平均值分别为16.9%、3.9%、4.8%和3.7%NaCleqv)。成岩成矿定年结果、各成矿阶段的成矿流体特征,结合锆石εHf(t)=-7.6--5.0、tDM2=1565-1711Ma,和石英矿物的δ18OH_(2)O值从第Ⅰ阶段(3.97‰-5.34‰)到第Ⅳ阶段(-4.99‰--5.10‰)逐渐降低的特点,以及区域岩体的地球化学特征,本文认为落家冲钨锡矿床是加里东期起源于元古宙地壳重熔的岩浆在经历了高分异演化作用后,流体的沸腾作用以及温度下降造成成矿流体中钨锡等矿质的沉淀所形成。 相似文献
956.
957.
青海虎头崖铜铅锌多金属矿床硫、铅同位素组成及成因意义 总被引:11,自引:0,他引:11
[摘 要] 青海虎头崖铜铅锌多金属矿是东昆仑祁漫塔格成矿带内多金属矿床的典型代表之一。本文对该矿床硫、铅同位素组成进行详细研究,探讨了成矿物质来源和矿床成因。结果表明,该矿床黄铜矿、方铅矿、闪锌矿、黄铁矿等硫化物的δ34S 值变化于+0.6‰~+8.3‰,平均+4.4‰,反映成矿流体中的硫为海水硫酸盐的地层硫和深源岩浆硫的混合硫,而不同矿带硫同位素均值的差别,可能与围岩地层硫的差异及参与程度有关。矿石矿物铅同位素组成总体变化较小(206Pb/204Pb、207Pb/204Pb 和208Pb/204Pb比值分别为18.476~18.688、15.560~15.688 和38.261~38.599),主要分布于造山带和上地壳铅演化线范围内,为岩浆作用导致的上地壳和地幔混合成因。由于赋矿层位及主控矿因素不同,各矿带的矿石铅同位素出现一定的差异。比如滩间山群内6号铜多金属矿点207Pb/204Pb 值和产于岩体与缔敖苏组接触带上的域矿带207Pb/204Pb 值相比,后者的上地壳铅参与程度较高,进一步证明壳幔混合作用对本矿区的影响。该矿床为与岩浆侵入活动密切相关的矽卡岩型铜铅锌多金属矿床。 相似文献
958.
吉林香炉碗子金矿床成矿地质特征及成因 总被引:1,自引:0,他引:1
吉林香炉碗子金矿位于华北地台北缘柳河地堑西侧太古宇鞍山群斜长角闪片麻岩,斜长角闪岩,变粒岩中,为一典型的隐爆角砾岩筒型中型金矿床。在空间和成因上受控于爱林东山,爱林西山隐爆角砾岩体。矿体呈脉状产于角砾岩内的蚀变破碎带中,流体包裹体以液相为主,盐度5.7% ̄13.5%,成矿温度173 ̄355℃,包裹体成分表明为H2O-CO2-NaCl体系。矿床成因属次火山岩隐爆期后成矿的蚀变岩型金矿。 相似文献
959.
秦王川盆地西缘断裂发育于陇中盆地地震构造区内部,本文对其进行了综合研究。浅层人工地震探测表明,该断裂在最小埋深130m处有显示,联合钻探结果表明该深度处为新近纪湖相沉积地层,泥岩层顶面向盆地方向呈斜坡状,槽探未揭露出断层。综合研究表明该断裂发育在新近纪地层内部,并未上穿第四纪沉积物,属于前第四纪隐伏断层。秦王川盆地在古近纪—新近纪山间泛湖盆的基础上,由于区域构造应力不均匀挤压抬升,形成山间负向地形,成为第四纪多变环境下河流堆积的拗陷盆地。秦王川盆地西缘断裂不具有控制中强地震空间分布的作用和形成地表破裂的能力,对盆地的构造稳定性不构成影响,亦不影响兰州新区的规划发展。 相似文献
960.
Kevin P. Blake 《第四纪科学杂志》2000,15(6):633-644
The study of De Geer moraines in Raudvassdalen shows that most De Geer moraines are likely to have a common origin at the grounding line of glaciers despite variability in composition of the ridges. Pebble fabric, grain‐size analysis and structures within exposures of De Geer moraines in the Raudvassdalen area, with compositions ranging from mostly till to mostly sorted sediment, indicate that the ridges all formed at the grounding line of a tidewater glacier by common processes: deposition of sorted sediments beyond the grounding line followed by deformation of pre‐existing sediments and deposition of till as the glacier overrode the ridges. The compositional variation of the ridges is probably related to the position of the section studied relative to the location of the outlet of subglacial streams. Ridges composed entirely of till form at locations remote from the outlet of subglacial streams, and ridges with a component of sorted sediments form in closer proximity to these streams. This unifying theory of De Geer moraine formation, along with theoretical and geological evidence showing that there are limited physical conditions where basal crevasses can form, suggests that the number of De Geer moraines interpreted to have formed in basal crevasses is probably unrealistic. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献