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矿集区找矿预测研究——以辽东青城子铅锌-金-银矿集区为例 总被引：7，自引：4，他引：3
矿集区找矿预测有着不同于典型矿床和区域性成矿预测的规律和特点,是在厘定区内主要类型矿床的成因类型基础上,以"三位一体"(即成矿地质作用与成矿地质体、成矿构造与成矿结构面、成矿作用特征标志)和成矿系统为主要内容开展工作。文章以辽宁青城子铅锌-金-银矿集区为例,系统总结了矿集区的矿床类型、岩浆-成矿系统、"三位一体"找矿预测要素等关键科学问题。青城子矿集区是中国重要的铅锌-金-银矿集区,由于多年的开采,青城子等矿山濒临危机,如何取得该地区找矿突破,是一个亟待解决的问题。对前人研究成果分析表明,该矿集区内铅锌矿床和金、银矿床的成因类型可能均属于岩浆热液型,而非元古代喷流沉积型,矿床的"层控"现象实为特定岩性界面控制的有利成矿结构面;成矿作用主要与印支期花岗斑岩有关,铅锌矿和金、银矿可能是同一岩浆系统演化的产物。在未来的找矿预测中,应重点开展以下5方面工作:(1)查明矿床的具体成矿地质体;(2)进一步提炼成矿期构造控矿规律和成矿结构面样式;(3)凝练有效的成矿作用特征标志,重点是与成矿有关的远程蚀变标志;(4)构建和完善矿集区中生代岩浆-成矿系统,并注意新矿种、新矿床类型的寻找;(5)探索研究矿集区的自然边界,扩大找矿范围和深度。 相似文献
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辽东青城子金银多金属成矿区综合信息找矿模型及找矿远景分析 总被引：1，自引：0，他引：1
辽东青城子地区是我国重要的有色和贵金属成矿区。在分析其成矿地质条件、地球化学和地球物理特征、遥感影像特征的基础上,建立了综合信息找矿模型,提出了有利的含矿层位、各级断裂构造及中生代岩体对金银多金属矿化起着重要的控制作用。在找矿模型的指导下,该地区主要通过详细地质调查、水系沉积物测量、高精度磁测扫面、遥感解译等工作,寻找与矿化有关的异常信息,进一步筛选出10余处可供调查评价并且资源潜力巨大的找矿远景区。 相似文献
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The initiation timing and mechanism of lithospheric thinning of the North China Craton (NCC) was still controversial. Late Triassic igneous rocks especially mantle derived mafic rocks would provide constrains on Early Mesozoic lithospheric mantle geodynamics and initiation of lithospheric thinning. This paper reports Late Triassic magmatic rocks, including lamprophyre, diorite dykes and biotite monzogranite cropped out in Qingchengzi district of Liaodong peninsula, northeastern NCC. LA–ICPMS zircon U–Pb dating yield ages of 210–227 Ma and 224 Ma for lamprophyres and biotite monzogranite respectively. Lamprophyre is ultrapotassic, strongly enriched in REE and LILEs, depleted in HFSEs, and negative Hf isotopes, which are discriminating signatures of crustal source, but distinguishingly high compatible element contents indicate the primary magma originated from mantle source—a fertile one. Lamprophyre derived from partial melting of an enriched lithospheric mantle, which was modified by slab-derived hydrous fluids/melts associated with deep subduction between the Yangtze Craton and the NCC. The diorite displays distinct features with relatively enriched Nb, Ta, HREE and depleted Th, U, which suggest it derived from a relatively depleted source. The depletion was caused by break-off of the Yangtze slab during deep subduction introducing asthenospheric mantle into the source. The biotite monzogranite shows adakitic affinity, and originated from partial melting of the thickened lower crust with addition of small proportion of mantle material. The recognition of Late Triassic magmatism implies extensional tectonic settings in Liaodong peninsula and suggests initiation of lithospheric thinning of North China Craton in eastern segment might begin early in Late Triassic. 相似文献
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Gang Yu Jiangfeng Chen Chunji Xue Yuchuan Chen Fukun Chen Xiaoyue Du 《Ore Geology Reviews》2009,35(3-4):367-382
The Qingchengzi orefield in northeastern China, is a concentration of several Pb–Zn, Ag, and Au ore deposits. A combination of geochronological and Pb, Sr isotopic investigations was conducted. Zircon SHRIMP U–Pb ages of 225.3 ± 1.8 Ma and 184.5 ± 1.6 Ma were obtained for the Xinling and Yaojiagou granites, respectively. By step-dissolution Rb–Sr dating, ages of 221 ± 12 Ma and 138.7 ± 4.1 Ma were obtained for the sphalerite of the Zhenzigou Zn–Pb deposit and pyrargyrite of the Ag ore in the Gaojiabaozi Ag deposit, respectively. Pb isotopic ratios of the Ag ore at Gaojiabaozi (206Pb/204Pb = 18.38 to 18.53) are higher than those of the Pb–Zn ores (206Pb/204Pb = 17.66 to 17.96; Chen et al. [Chen, J.F., Yu, G., Xue, C.J., Qian, H., He, J.F., Xing, Z., Zhang, X., 2005. Pb isotope geochemistry of lead, zinc, gold and silver deposit clustered region, Liaodong rift zone, northeastern China. Science in China Series D 48, 467–476.]). Triassic granites show low Pb isotopic ratios (206Pb/204Pb = 17.12 to 17.41, 207Pb/204Pb = 15.47 to 15.54, 208Pb/204Pb = 37.51 to 37.89) and metamorphic rocks of the Liaohe Group have high ratios (206Pb/204Pb = 18.20 to 24.28 and 18.32 to 20.06, 207Pb/204Pb = 15.69 to 16.44 and 15.66 to 15.98, 208Pb/204Pb = 37.29 to 38.61 and 38.69 to 40.00 for the marble of the Dashiqiao Formation and schist of the Gaixian Formation, respectively).Magmatic activities at Qingchengzi and in adjacent regions took place in three stages, and each contained several magmatic pulses: ca. 220 to 225 Ma and 211 to 216 Ma in the Triassic; 179 to 185 Ma, 163 to 168 Ma, 155 Ma and 149 Ma in the Jurassic, as well as ca. 140 to 130 Ma in the Early Cretaceous. The Triassic magmatism was part of the Triassic magmatic belt along the northern margin of the North China Craton produced in a post-collisional extensional setting, and granites in it formed by crustal melting induced by mantle magma. The Jurassic and Early Cretaceous magmatism was related to the lithospheric delamination in eastern China. The Triassic is the most important metallogenic stage at Qingchengzi. The Pb–Zn deposits, the Pb–Zn–Ag ore at Gaojiabaozi, and the gold deposits were all formed in this stage. They are temporally and spatially associated with the Triassic magmatic activity. Mineralization is very weak in the Jurassic. Ag ore at Gaojiabaozi was formed in the Early Cretaceous, which is suggested by the young Rb–Sr isochron age, field relations, and significantly different Pb isotopic ratios between the Pb–Zn–Ag and Ag ores. Pb isotopic compositions of the Pb–Zn ores suggest binary mixing for the source of the deposits. The magmatic end-member is the Triassic granites and the other metamorphic rocks of the Liaohe Group. Slightly different proportions of the two end-members, or an involvement of materials from hidden Cretaceous granites with slightly different Pb isotopic ratios, is postulated to interpret the difference of Pb isotopic compositions between the Pb–Zn–(Ag) and Ag ores. Sr isotopic ratios support this conclusion. At the western part of the Qingchengzi orefield, hydrothermal fluid driven by the heat provided by the now exposed Triassic granites deposited ore-forming materials in the low and middle horizons of the marbles of the Dashiqiao Formation near the intrusions to form mesothermal Zn–Pb deposits. In the eastern part, hydrothermal fluids associated with deep, hidden Triassic intrusions moved upward along a regional fault over a long distance and then deposited the ore-forming materials to form epithermal Au and Pb–Zn–Ag ores. Young magmatic activities are all represented by dykes across the entire orefield, suggesting that the corresponding main intrusion bodies are situated in the deep part of the crust. Among these, only intrusions with age of ca. 140 Ma might have released sufficient amounts of fluid to be responsible for the formation of the Ag ore at Gaojiabaozi.Our age results support previous conclusions that sphalerite can provide a reliable Rb–Sr age as long as the fluid inclusion phase is effectively separated from the “sulfide” phase. Our work suggests that the separation can be achieved by a step-resolution technique. Moreover, we suggest that pyrargyrite is a promising mineral for Rb–Sr isochron dating. 相似文献
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The Qingchengzi orefield is a large polymetallic ore concentration area in the Liaodong peninsula,northeastern China,that includes twelve Pb-Zn deposits and five Au-Ag deposits along its periphery.The ore-forming age remains much disputed,which prevents the identification of the relationship between the mineralization and the associated magmatism.In this paper,we quantitatively present the feasibility of making ore mineral ~(40)Ar/~(39)Ar dating and report reliable ~(40)Ar/~(39)Ar ages of lamprophyre groundmass,K-feldspar and sphalerite from the Zhenzigou deposit.Direct and indirect methods are applied to constrain the timing of mineralization,which plays a vital role in discussing the contribution of multistage magmatism to ore formation.The low-potassium sphalerite yielded an inverse isochron age of 232.8±41.5 Ma,which features a relatively large uncertainty.Two lamprophyre groundmasses got reliable inverse isochron ages of 193.2±1.3 Ma and 152.3±1.5 Ma,respectively.K-feldspar yielded a precise inverse isochron age of 134.9±0.9 Ma.These four ages indicate that the mineralization is closely associated with Mesozoic magmatism.Consequently,regarding the cooling age of the earliest Mesozoic Shuangdinggou intrusion(224.2±1.2 Ma)as the initial time of mineralization,we can further constrain the age of the sphalerite to 224–191 Ma.These new and existing geochronological data,combined with the interaction cutting or symbiotic relationship between the lamprophyre veins and ore veins,suggest that the Pb-Zn-Au-Ag mineralization in the Qingchengzi orefield mainly occurred during three periods:the late Triassic(ca.224–193 Ma),the late Jurassic(ca.167–152 Ma)and the early Cretaceous(ca.138–134 Ma).This polymetallic deposits are shown to have been formed during multiple events coinciding with periods of the Mesozoic magmatic activity.In contrast,the Proterozoic magmatism and submarine exhalative and hydrothermal sedimentation in the Liaolaomo paleorift served mainly to transport and concentrate the ore-forming substances at the Liaohe Group with no associated Pb-Zn-Au-Ag mineralization. 相似文献
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辽宁青城子铅锌多金属矿田晚三叠世岩浆岩年代学、地球化学及地质意义 总被引：7，自引：1，他引：6
辽宁青城子铅锌矿田产出在辽东裂谷凹陷带,是中国北方重要的铅锌金银多金属矿田。研究表明,矿区内发育的以双顶沟黑云母二长花岗岩和新岭花岗岩为代表的晚三叠世花岗质岩浆事件,应与本区的矿化作用密切相关。LA-ICPMS锆石U-Pb定年结果显示双顶沟岩体侵位时间为224.2±1.2Ma。双顶沟岩体岩石化学组成呈现 SiO2 69.07%~71.31%,K2O 3.53%~5.22%, Na2O 3.87%~4.14%,属于钙碱性岩石系列。Al2O3为12.46%~14.48%,A/CNK<1,具有准铝质特征。微量元素数据显示稀土总量较高,轻重稀土元素之间强烈分馏, , Eu负异常不明显(δEu=0.68~0.97)。富集大离子亲石元素Rb、Th、K、Pb等,而亏损高场强元素Nb、Ta、P、Ti等。具有高Sr,Ba含量,低的Y,Yb含量特征,属于具有类似埃达克质亲和性的I型花岗岩,具有高Nb/Ta(18.4~21.2),上述岩石地球化学特征,表明其岩浆源区残留固相矿物组合中包含可观的石榴子石和金红石,可能起源于加厚下地壳的部分熔融,并可能存在与幔源基性岩浆混合作用。推测扬子和华北板块深俯冲过程中板片断离可能是诱发与成矿有关岩浆的地球动力学原因。 相似文献
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对辽宁青城子铅锌-银-金矿床的主要矿石矿物方铅矿、闪锌矿和黄铁矿进行了显微鉴定、电子探针和ICP-MS分析，获得它们的固结顺序为：黄铁矿早于闪锌矿，二者早于方铅矿（闪锌矿交代黄铁矿，方铅矿交代前两者）。从硫化物成分空间分布可以判断成矿流体以甸南-榛子沟为中心分别向二道-喜鹊沟和大地-白云迁移。根据方铅矿固结温度（327℃）参考石英流体包裹体均一温度（322℃），限定以方铅矿为主的矿床其硫化物形成温度约为322～327℃；利用Cd在方铅矿-闪锌矿分配系数温度计获得铅锌矿成矿温度在344～464℃之间，结合闪锌矿出溶黄铜矿温度（高于350℃），参考石英流体包裹体均一温度（300～360℃），并参考黄铁矿发生脆性变形温度（400℃），获得以闪锌矿为主的矿床硫化物形成温度约为360～400℃，银铅锌矿床的成矿温度被限定在390～400℃；由于自然金主要赋存在黄铁矿微裂隙中，利用黄铁矿发生脆性变形温度并结合石英流体包裹体温度（230～370℃）约束金成矿温度约为370～400℃。成矿温度较高可能归因于样品采集位置较深所致；最后利用矿石矿物、侵入岩、围岩微量元素对比分析判断成矿流体与中生代（特别是印支期）侵入岩具有亲缘性，根据印支期岩浆混合特征认为岩浆混合作用可能对本地区成矿作用具有重要贡献。 相似文献
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大量研究表明辽宁青城子地区主要成矿作用与印支期岩浆活动有密切关系,为了进一步研究印支期岩浆活动与成矿关系,文章在详细野外工作的基础上,对印支期侵入岩体进行了岩石地球化学测试分析。结果表明,青城子地区印支期花岗岩的w(SiO2)介于61.67%～77.69%,w(K2O)介于3.96%～6.67%,w(Na2O)为0.04%～4.42%,里特曼指数为0.57～5.19,多数小于3.3,主要为高钾钙碱性和钾玄岩系列;在以w(SiO2)为横坐标、其他氧化物为纵坐标的哈克图解中,除了w(Na2O)、w(K2O)与w(SiO2)的线性关系不明显外,其他氧化物均与w(SiO2)呈线性关系,说明它们具有明显的岩浆演化关系;微量元素均富集大离子亲石元素,亏损高场强元素,原始地幔标准化配分曲线呈右倾模式,稀土元素球粒陨石标准化配分模式呈轻稀土元素富集、重稀土元素亏损的右倾模式;构造判别图指示了青城子地区印支期岩浆活动产于同碰撞大地... 相似文献
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青城子矿集区印支期岩浆作用形成岩基状双顶沟岩体及岩脉状石英二长斑岩等,双顶沟岩体根据其岩相学特征可划分为主体相和中心相两个岩相带,主体相内含有大量暗色微粒包体,并常见矿物不平衡结构,显示岩浆混合的特征。在岩石地球化学方面,包体与寄主岩石的主要氧化物之间具有良好的线性关系,寄主岩石和包体的稀土元素配分曲线和微量元素蛛网图形态相似,指示寄主岩石与包体在岩石形成过程中发生过成分交换及均一化,也显示岩浆混合特征。双顶沟岩体主体相具有高Ba-Sr花岗岩特征,可能为加厚下地壳部分熔融形成的熔体与富集地幔岩浆混合作用的产物,中心相则为主体相经过长石、角闪石、黑云母等的分离结晶作用而形成。石英二长斑岩脉可能为双顶沟岩体演化的浅成相,两者具有相同的源区和成因,矿集区内铅锌、金银矿床的形成可能与岩浆混合作用演化形成的石英二长斑岩相关。 相似文献