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1.
胶东西北部金矿剥蚀程度及找矿潜力和方向——来自磷灰石裂变径迹热年代学的证据 总被引：5，自引：2，他引：3
矿床形成后会经历不同形式的变化,区域隆升与剥蚀是影响矿床变化保存最为关键的因素之一。构造-热年代学是目前广泛运用于研究区域隆升剥蚀的一种重要手段,本文以我国最大金矿集中区———胶东西北部金矿及赋矿围岩玲珑花岗岩为研究对象,尝试将构造-热年代学引用到矿床成矿后变化与保存研究。通过磷灰石裂变径迹热年代学测试获得玲珑花岗岩距今110Ma以来的隆升演化历史,结果显示岩体剥蚀速率很小,平均0.0303±0.0044mm.a-1,自金矿形成后区域热-构造运动趋于平静,这对矿床的保存非常有利。胶东金矿成矿深度范围集中于4~10km,根据剥蚀速度计算玲珑花岗岩剥蚀量仅为2.0~4.2km,远未达到金矿最大成矿深度。当前本区金矿勘探和开采深度普遍小于2km,深部金矿找矿潜力良好。 相似文献
2.
矿床形成深度及成矿后的变化与保存是目前深部找矿亟待解决的关键问题.选取4个成矿年龄均为130 Ma左右的典型玢岩铁矿, 分别为宁芜盆地中矿体已经出露地表并经受过剥蚀的东山铁矿和矿体埋藏距地表 40 m以下的梅山铁矿, 庐枞盆地中矿体埋藏距地表400 m以下的罗河铁矿和矿体埋藏距地表600 m以下的泥河铁矿, 采用双重定年技术对这4个矿床主成矿阶段矿石矿物组合中的磷灰石进行了裂变径迹研究.结果显示: (1)东山铁矿AFT合并年龄为106.3±5.4 Ma, 梅山铁矿为94.2±4.0 Ma, 罗河铁矿为81.3±4.0 Ma, 泥河铁矿为79.1±3.3 Ma, 且AFT年龄和围限径迹长度随样品埋藏深度减小而增大, 分别更接近成矿年龄和原始径迹长度, 显示4个矿床成矿后差异抬升剥蚀作用导致磷灰石样品通过部分退火带时的冷却速率存在差别; (2)热史模拟反映这4个矿床成矿后均经历了早期短暂快速冷却和后期长期缓慢冷却2个阶段, 两阶段之间的拐点温度接近, 对应深度为1.7~1.8 km, 结合其他证据证明宁芜、庐枞盆地玢岩铁矿成矿深度均为2 km左右.说明这4个矿床现今埋藏深度的差异主要是由于成矿后的抬升、剥蚀作用导致.(3)自110 Ma以来宁芜盆地的整体抬升剥蚀幅度大于庐枞盆地, 导致宁芜盆地大部分玢岩铁矿矿体接近或暴露地表.2个盆地早期抬升剥蚀作用与区域性黄桥事件同步. 相似文献
3.
文章在梳理分析相关文献的基础上,综合考虑区域构造成矿背景、超大型金矿形成条件、金矿脉形成深度及隆升剥蚀幅度等方面的因素,认为哈达门沟—柳坝沟金矿田经历了漫长的地质演化,是多期次叠加成矿;在海西中、晚期初步富集,到印支期大规模成矿,再到燕山期进一步叠加富集并遭受后生改造;主成矿期为印支期,主成矿年代集中于217～240 Ma之间. 相似文献
4.
在大量典型矿床实地调查和国内外综合对比研究的基础上,基于深部找矿的现实需要和存在问题,本文首先回顾评述了主要矿床类型的原始成矿深度,按受控于中下地壳尺度大规模岩浆堆积体的超深成岩浆矿床与受控于流体渗透率制约的中上地壳深成、中成和浅成岩浆热液矿床序列展开。在此基础上尝试探讨主要类型矿床的最大延深垂幅,探讨分析了以Bushveld层状岩体和Voisey’s Bay小岩体为代表的铜镍矿床、驱龙为代表的斑岩铜矿床、Muruntau为代表的造山型金矿、胶东金矿省的已控制延深垂幅、剥蚀程度以及深部可能的延深空间。内生矿床系统具有很宽的成矿深度范围,大型层状岩体的成矿深度可逾20 km,最大矿化垂直延深幅度可达6~8 km。岩浆热液矿床的最大成矿深度以地壳尺度流体渗透的下限为底界,其中造山型金矿床成矿深度最大(约12~15 km),伟晶岩和花岗岩型矿床次之,斑岩型矿床居中(约2~6 km),浅成低温金银矿床深度最浅(1 km至近地表);相应的最大延深垂幅则依次可达4~7 km、2~3 km和1 km。评述了高渗透性的聚矿构造空间、成矿作用顶峰、合适的矿床保存条件等控制因素及部分标志。并对如何确定合理统一的成岩成矿深度(压力)的估算方法以及确定最大成矿深度与矿化体系最大延深幅度的理论依据、判断标志、综合辨识方法体系等未来研究方向进行了展望。 相似文献
5.
胶东西北部金矿床深部资源潜力与找矿方向 总被引：3，自引：0，他引：3
[摘摇要]结合胶东地区近年来金矿勘查的重大突破,通过对控矿断裂构造网络、成矿流体来源、成
矿深度估算和剥蚀程度的综合分析,认为胶东地区具有良好的区域金成矿地质条件和深部找矿前景。
胶东地区具有三山岛、焦家、招平3 条主要的控矿断裂和众多次级断裂,构成成矿流体活动和金矿床就
位的构造网络。成矿流体具有壳幔混合特征,暗示成矿作用深部延伸潜力可观。近年来的勘查实践已
经发现众多深部资源,证明胶东地区深部找矿切实可行。通过流体包裹体压力和花岗岩形成深度综合
分析,认为胶东金矿床成矿深度上限为2～3 km,成矿深度下限5～8 km,后期剥蚀程度不超过3 km,因
此区域上3 km 以浅甚至5 km 以浅均具有找矿前景。三山岛断裂与焦家断裂深部可能在4 km 左右深
度交汇,其交汇部位可能发育隐伏的巨型金成矿带。 相似文献
6.
矿床变化与保存研究的裂变径迹新途径 总被引：3，自引：0，他引：3
矿床形成后的变化与保存是矿床学研究与找矿勘探中一项极其重要但仍需进一步加强的基础性工作。影响矿床变化与保存的众多因素中,区域隆升与剥蚀是最为关键的因素之一。裂变径迹法是研究区域隆升与剥蚀的一种有效手段,它能为我们提供剥蚀速率以及剥蚀量的定量数据。一些产于花岗质岩体内与岩体有成因联系的矿床,其成矿深度可以通过详细的流体包裹体研究来获得。通过成矿深度与岩体剥蚀深度对比分析,能使我们更好地了解矿床形成后变化保存条件。裂变径迹法与流体包裹体研究相结合是矿床形成后变化与保存研究一种切实可行的方法。 相似文献
7.
西藏冈底斯矿带成矿作用及远景分析 总被引：5，自引：1，他引：4
冈底斯带矿床众多,类型复杂,主要有斑岩型铜（金钼）矿床、矽卡岩型铁铜-铅-锌（银）矿床、层控铅-锌-银矿床、火山岩型金-银矿床及雄村式铜-金矿床。矿床地质特征和同位素年龄表明,冈底斯带南部的矿床与新特提斯洋壳向北俯冲-陆陆碰撞及碰撞期后的构造岩浆事件有关;冈底斯带北部的矿床与班公湖-怒江洋壳向南俯冲-陆陆碰撞及碰撞期后构造岩浆事件有关。冈底斯带与洋壳的俯冲-碰撞有关的岩浆活动强烈,成矿条件优越。西藏高原在碰撞后发生了快速抬升剥蚀,部分矿床顶部出现低温组合矿化,多数矿床保存良好。 相似文献
8.
Geoelectrical Structure of the Crust and Upper Mantle in the Qinling and Adjacent Regions 总被引：2，自引：0，他引：2
LI Li JIN Guoyuan YANG Piyuan LIU Yuhua Institute of Geophysical Geochemical Exploration Ministry of Geology Mineral Resources Langfang Hebei China ZHUO Xianjun Department of Petroleum Exploration of Zhejiang Province Yuha 《Continental Dynamics》1999,(1)
１．Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｔｈｅｄａｔａｏｆｔｈｉｓｓｔｕｄｙａｒｅｃｏｌｌｅｃｔｅｄｆｒｏｍ２１６ｍａｇｎｅｔｏｔｅｌｌｕｒｉｃｓｏｕｎｄｉｎｇｐｏｉｎｔｓｏｎｔｈｅｆｏｌｌｏｗｉｎｇｐｒｏｆｉｌｅｓａｃｒｏｓｓｔｈｅＱｉｎｌｉｎｇｏｒｏｇｅｎ,ｔｈｅＹｅｘｉａｎ（ｉｎＨｅｎａｎＰｒｏｖｉｎｃｅ）－Ｎａｎｚｈａｎｇ（ｉｎＨｕｂｅｉＰｒｏｖｉｎｃｅ）Ｐｒｏｆｉｌｅ（Ｌｉｅｔａｌ．,１９９８）,ｔｈｅＬｕｏｙａｎｇ（ｉｎＨｅｎａｎＰｒｏｖｉｎｃｅ）－Ｓｈｉｙａｎ（ｉｎＨｕｂｅｉＰｒｏｖｉｎ… 相似文献
9.
本文通过冀北金矿化集中区的地质背景，矿床地质、地球物理特征及地球化学特征的综合研究，提出了富碱热流体在古老地壳深大断裂系中活动对地台活化，岩浆作用乃至成金作用的重要意义，将产于变质岩中金矿床与岩浆岩中金矿床的成因统一起来。它们的金活化条件及成矿机制是相同的，成矿物质来源为中生代地幔与古老地壳的混合来源。 相似文献
10.
Yu. G. Safonov 《Geology of Ore Deposits》2010,52(6):438-458
The issues of the theory of gold deposit formation are considered. These issues were crucial in the works by N.V. Petrovskaya.
The systematics of gold deposits based on stable mineral assemblages and mineral and geochemical types of ores and their families
characteristic of certain groups of gold deposits is consonant with contemporary analogue classifications of ore deposits,
which, however, require improvement by means of developing their genetic version. Petrovskaya’s proposed subdivision of gold
deposits into families distinguished by depth of their formation is such a version, because in Petrovskaya’s understanding,
the factor of depth integrates genetic features of deposits formed at shallow, medium, and great depths. According to recent
data, the depth interval of localization of ore deposits is estimated at 15–20 km instead of 6–10 km suggested earlier; thus,
the intervals of medium and great depths increase. Attention is called to the Petrovskaya’s ideas of stadial progressive development
of ore formation with change in pyrite-arsenopyrite mineralization by base-metal and telluride mineralization along with advanced
and concomitant deposition of quartz. The stadial formation of shallow-seated deposits and colloidal mineral formation therein,
as well as the concept of gel metasomatism and mechanisms of accompanying destruction of preceding mineral assemblages developed
by Petrovskaya, are considered and their implications are illustrated by specific deposits. Petrovskaya’s views on sources
of ore matter and the polygenetic character of gold and Au-bearing deposits are discussed. 相似文献
11.
构造热演化是沉积盆地基础地质研究的重要内容,更是油气勘探中不可或缺的部分,多种古地温方法的综合对比研究是目前热史研究主要发展趋势。本文将裂变径迹(FT)和(U-Th)/He热年代学、镜质体反射率法(Ro)和盆地模拟等技术相结合,运用正演和反演的方法重建了川东北地区埋藏–剥露热演化历史。研究表明川东北地区自晚白垩世埋深达到最大后进入剥蚀阶段,大约从92 Ma开始隆升,经历了快速隆升–缓慢隆升–加速隆升三个阶段,整个过程的剥蚀量大约3~4 km,且两次大的剥露过程分别受控于雪峰山的隆起造山以及大巴山的推覆和青藏高原的隆升作用。研究还建立了综合热年代学、Ro和盆地模拟技术恢复复杂构造–热演化历史的方法,这对于复杂环境下的构造热演化历史的恢复以及海相油气勘探具有重要的意义。 相似文献
12.
热液矿床原生晕具有明显的分带特征,其中含矿溶液在运动方向上显示出的轴向分带尤其重要,分带序列的建立对于评价隐伏矿体的规模、埋藏深度以及剥蚀水平有指导性意义,在很大程度上提高了地球化学找矿方法的找矿深度。针对黑龙江省三道湾子金矿,计算总结出轴向分带序列特征,确定矿体的前缘和尾晕指示元素以及分带性指数,结合矿区已知矿体对所研究矿脉剥蚀程度和深部成矿潜力进行评价。 相似文献
13.
Apatite fission track thermochronology from Early Palaeozoic granitoids centred around the Kosciuszko massif of the Snowy Mountains, records a denudation history that was episodic and highly variable. The form of the apatite fission track age profile assembled from vertical sections and hydroelectric tunnels traversing the mountains, together with numerical forward modelling, provide strong evidence for two episodes of accelerated denudation, commencing in Late Permian—Early Triassic (ca 270–250 Ma) and mid‐Cretaceous (ca 110–100 Ma) times, and a possible third episode in the Cenozoic. Denudation commencing in the Late Permian—Early Triassic was widespread in the eastern and central Snowy Mountains area, continued through much of the Triassic, and amounted to at least ～2.0–2.4 km. This episode was probably the geomorphic response to the Hunter‐Bowen Orogeny. Post‐Triassic denudation to the present in these areas amounted to ～2.0–2.2 km. Unambiguous evidence for mid‐Cretaceous cooling and possible later cooling is confined to a north‐south‐trending sinuous belt, up to ～15 km wide by at least 35 km long, of major reactivated Palaeozoic faults on the western side of the mountains. This zone is the most deeply exposed area of the Kosciuszko block. Denudation accompanying these later events totalled up to ～1.8–2.0 km and ～2.0–2.25 km respectively. Mid‐Cretaceous denudation marks the onset of renewed tectonic activity in the southeastern highlands following a period of relative quiescence since the Late Triassic, and establishes a temporal link with the onset of extension related to the opening of the Tasman Sea. Much of the present day relief of the mountains resulted from surface uplift which disrupted the post‐mid‐Cretaceous apatite fission track profile by variable offsets on faults. 相似文献
14.
刺猬沟矿床是中国东北地区典型的低硫化型浅成低温热液型金矿。为确定该矿床的成矿物理化学条件及形成深度,对不同标高的同一条含矿石英脉中的流体包裹体开展了显微测温和激光拉曼光谱分析。结果表明,含金石英--方解石脉中的石英与方解石主要发育气液两相及少量富液相包裹体,包裹体均一温度变化范围为112. 2 ℃ ～ 377. 7 ℃,集中在200 ℃ ～ 240 ℃,盐度( w ( NaCl) ) 为0. 18% ～ 10. 87%,平均值为3. 43%,成矿流体密度为0. 57 g /cm3 ～ 1. 00 g /cm3,平均值为0. 89 g /cm3。结合包裹体气相组分的激光拉曼光谱分析认为,成矿流体属低温、低盐度、低密度的NaCl --H2O ( --CO2 ) 体系。根据包裹体测温结果,估算出该矿床的成矿压力为7. 99 ～ 37. 89 MPa,平均值为14. 92 MPa,对应的成矿深度为0. 27 ～ 1. 26 km,平均值为0. 50 km。与国内外同类矿床的对比研究表明,该矿床剥蚀深度较小,深部仍具有一定的找矿远景。 相似文献
15.
湘黔地区“卡林型”金矿中金的赋存形式 总被引：8，自引：0，他引：8
对矿石的化学物相分析结果表明，湖南─贵州─带“卡林型”金矿原生矿石中的金主要呈微粒状单质金被包裹于硫化物及以绢云母为主的粘土矿物中，反映了金的矿化作用与黄铁矿化和绢云母化等是同时发生的。不同的“卡林型”金矿床之间，由于形成的物理化学条件的差异，其主要载金矿物的种类也不相同。表生氧化带中，载金矿物硫化物和绢云母发生了氧化和分解作用，使矿石中的大部分金转化为游离态形式存在，提高了矿石的可选性。 相似文献
16.
The St. Marys Basin of mainland Nova Scotia, Canada, consists of Late Devonian–Early Carboniferous clastic rocks of the Horton
Group deposited in the waning stages of the ca. 420–360 Ma Acadian orogeny in the Canadian Appalachians. Clast lithologies
and lithogeochemical analyses indicate that the detritus was predominantly derived from the Meguma terrane that occurs to
the south of the basin. The Meguma terrane contains abundant mesothermal gold deposits that are coeval with peak magmatic
activity from ca. 380 to 370 Ma and underwent rapid uplift and erosion between ca. 370 and 360 Ma. Within the St. Marys Basin,
the contact between the lacustrine Little Stewiacke River Formation and the fluviatile Barrens Hills Formation is interpreted
to represent a shoreline and a potentially favorable environment for depositing paleoplacer gold. Geochemical analyses of
lithologies adjacent to this contact indicate that the siltstones are predominantly derived from Meguma terrane metasedimentary
rocks, whereas the sandstones and conglomerates are predominantly derived from Meguma terrane granitoids. Geochemical and
mineralogical analysis indicate the accumulation of heavy minerals including zircon and gold. Micron-scale (<150 μm) gold
identified in the matrix of the conglomerates has a “nuggety” appearance and flakey microtexture indicative of a detrital
origin. This observation indicates that the mesothermal deposits were exhumed by the latest Devonian, consistent with regional
tectonic syntheses that invoke rapid uplift of the Meguma terrane following peak orogenic activity. This study suggests that
favorable depositional environments for paleoplacer deposits may occur in Horton Group rocks that are derived from the Meguma
terrane.
Received: 27 May 1999 / Accepted: 16 May 2000 相似文献
17.
克鲁-冲木达矿集区位于西藏南部扎囊-桑日之间,累计估算铜金属资源量达200多万t.文章从"景"、"场"、"相"、"床"金属成矿省等级体制出发,阐述了该矿集区在印-亚陆陆碰撞"陆内汇聚-地壳分层加厚-重力均衡调整"的高原隆升过程中的成矿地质背景,指出区内存在着与碰撞挤压流体迁移汇聚有关的层控铜矿床、碰撞后伸展环境中夕卡岩铜矿床、斑岩型铜矿床3种矿床类型.利用"成矿构造聚敛场"观点分析成矿资源潜力,并指明了找矿方向. 相似文献
18.
一、概述包体是矿物形成过程中被捕获的成矿介质,被称为成矿流体的样品。它是矿物最重要的标型特征之一。可作为译解成矿作用,特别是内生成矿作用的密码。因此,包体是一种最好的材料,可用于测定矿物、矿床或其他地质体形成过程中的物理地球化学作用的温度、压力、介质成分及性质等。用这些参数,可以有助于解决有关矿床成因、找矿标志、成矿规律及指 相似文献
19.
The Laloki and Federal Flag deposits are two of the many (over 45) polymetallic massive sulfide deposits that occur in the Astrolabe Mineral Field, Papua New Guinea. New data of the mineralogical compositions, mineral textures, and fluid inclusion studies on sphalerite from Laloki and Federal Flag deposits were investigated to clarify physiochemical conditions of the mineralization at both deposits. The two deposits are located about 2 km apart and they are stratigraphically hosted by siliceous to carbonaceous claystone and rare gray chert of Paleocene–Eocene age. Massive sulfide ore and host rock samples were collected from each deposit for mineralogical, geochemical, and fluid inclusion studies. Mineralization at the Laloki deposit consists of early‐stage massive sulfide mineralization (sphalerite‐barite, chalcopyrite, and pyrite–marcasite) and late‐stage brecciation and remobilization of early‐stage massive sulfides that was accompanied by late‐stage sphalerite mineralization. Occurrence of native gold blebs in early‐stage massive pyrite–marcasite‐chalcopyrite ore with the association of pyrrhotite‐hematite and abundant planktonic foraminifera remnants was due to reduction of hydrothermal fluids by the reaction with organic‐rich sediments and seawater mixing. Precipitation of fine‐grained gold blebs in late‐stage Fe‐rich sphalerite resulted from low temperature and higher salinity ore fluids in sulfur reducing conditions. In contrast, the massive sulfide ores from the Federal Flag deposit contain Fe‐rich sphalerite and subordinate sulfarsenides. Native gold blebs occur as inclusions in Fe‐rich sphalerite, along sphalerite grain boundaries, and in the siliceous‐hematitic matrix. Such occurrences of native gold suggest that gold was initially precipitated from high‐temperature, moderate to highly reduced, low‐sulfur ore fluids. Concentrations of Au and Ag from both Laloki and Federal Flag deposits were within the range (<10 ppm Au and <100 ppm Ag) of massive sulfides at a mid‐ocean ridge setting rather than typical arc‐type massive sulfides. The complex relationship between FeS contents in sphalerite and gold grades of both deposits is probably due to the initial deposition of gold on the seafloor that may have been controlled by factors such as Au complexes, pH, and fO2 in combination with temperature and sulfur fugacity. 相似文献
20.
对黔西南卡林型金矿集区开展矿田、矿床 (点) 剥蚀程度研究,能为新一轮找矿勘查布局提供有力支撑.以热液渗滤晕分带理论为指导,依据区内金矿床原生晕在空间中存在分带性以及次生异常与金矿床在地表呈现总体无偏特征,构建了大区域尺度量纲中能总体反映成矿元素分散流与原生晕共性特征的元素分带序列,计算了基于序列中元素区域化探扫面数据多重分形奇异性分析的前缘元素与尾部元素地球化学强度“对比值”,研制了矿田及其附近以“对比值”数据结构为主体的“低-浅-中-高”4个级别剥蚀程度定量评价指标,并结合实地地质特征开展综合评价工作.给出区内10个矿田和15个主要金矿床 (点) 的剥蚀程度评价结果,总体显示出右江区矿田剥蚀程度低于扬子区,泥堡、紫木凼、水银洞、丫他、烂泥沟等中-特大型金矿床剥蚀程度皆为低-浅剥蚀,而资源量相对较小的板其、戈塘、老万场等金矿床剥蚀程度普遍偏高.在此基础上,通过戈塘与水银洞金矿的进一步地质比对,论证了评价结果逼进了勘查事实并可以扩展到区内有一定勘查程度的地区.此外,对评价结果的分析表明,“对比值”异常是寻求找矿突破和现有矿床 (点) 深部成矿预测的主要评价指标之一,对找矿勘查有重要指示作用.据此初步提出水银洞金矿床及其以东的深部、戈塘金矿床北西二叠系与三叠系接触带附近、上大观矿点深部等14处深部找矿潜力较大的地区. 相似文献