地幔热柱多级演化及其幔枝构造成矿控矿——以胶西北郭家店幔枝构造为例

文章简要介绍了幔枝构造成矿理论,探讨了幔枝构造的特征、单元划分、断裂构造体系以及成矿控矿作用。在燕山运动晚期,华北东部地区进入了以伸展构造为主的地幔热柱演化阶段,在胶西北地区形成了莱阳地幔亚热柱及其外围郭家店、栖蓬、牟乳等幔枝构造。其中,郭家店幔枝构造于燕山运动晚期发生强烈的构造活动,总体形成了以焦家断裂为主的拆离带和与其相交的以三山岛断裂为反向铲状断裂的构造体系,同时控制着玲珑、焦家、三山岛等一系列大型—超大型矿床的形成。在众多成矿控矿因素中,区域性断裂构造是重要的主导性因素,既为成矿流体的运移提供了通道,又为成矿储矿提供了有利空间。深源含矿流体可通过地幔热柱→地幔亚热柱→幔枝构造→有利构造扩容带,即脆韧性-韧脆性剪切带、侵入岩体的内外接触带、密集的构造裂隙带、各种脉岩与围岩的接触带等有利构造部位集聚成矿。近年来在胶西北深部勘查发现,浅部沿断裂展布的若干个大—中型金矿在其深部的成矿蚀变构造带可能是连为一体的,一起组合成为超大型金矿。     

Characteristics of mantle branch structure in western Shandong and its roles in minerogenesis and ore-controlling

1 The rise of the problem The region of western Shandong has been attracting more and more attention of geologists because of its unique geological features and abundant mineral resources, and it has been well geologically documented (Lin Jingqian et al.…     

鲁西幔枝构造及其控矿特征

内容摘要: 从区域地层(岩体)中老外新分布,环状、放射状断裂的展布,轴部缓倾拆离滑脱构造的发育,幔源岩浆活动以及区域岩石学、岩石化学、同位素地质学等方面,探讨了鲁西幔枝构造特征。研究认为鲁西地区北西向陡倾韧性剪切带切割了深部华北地幔亚热柱向外拆离的地幔岩,导致其减压释荷形成深熔岩浆,强烈而完整的岩浆演化序列表现出岩浆基性程度由高变低、侵入深度由深变浅、围岩蚀变由强变弱的总体演化趋势。幔枝构造演化对内生成矿作用具有明显的控制作用,并带动围岩一起隆升,形成了典型的鲁西幔枝构造。其顶部发育的拆离掀斜断块,使部分内生矿产被抬升到浅部。     

Guojiadian Mantle Branch Structure and Its Ore-Controlling , Zhaoyuan,Shandong Province, China

Please refer to the attachment(s) for more details.     

黔西北地区铅锌矿床控矿构造与成矿

黔西北铅锌成矿区是川-滇-黔铅锌成矿域重要组成部分。文章通过总结黔西北地区铅锌矿床产出的区域地质背景、几个典型矿床的地质特征及研究区内构造展布与矿床（点）分布之间的关系,提出构造是区域铅锌矿床的主要控矿因素,构造对成矿具分级控制特点,强调研究区内构造体系是找矿突破的关键所在。     

胶东东部地区元古宙花岗岩类的地球化学及岩石成因

胶东东部地区的元古宙花岗岩－片麻岩杂岩,可分为：（１）石英闪长质－英云闪长质－花岗闪长质片麻岩、（２）二长花岗质－钾长花岗质片麻岩和（３）淡色花岗岩三套岩石。它们之间可识别侵位先后关系,岩相中普遍存在残留的斜长石板状晶体、并具环带结构为主的原生深成岩的矿物相组构,地球化学成分演化各具独立性,并具有深熔花岗岩的性质,结合同位素年龄资料,确立它们是元古宙不同造山阶段形成的花岗岩。岩石中普遍存在Ｔｉ、Ｙ、Ｓｒ、Ｎｉ及Ｍｇ等元素的强烈亏损,表明岩浆来源并非直接来源于上地幔或下地壳,它们是元古宙不同阶段已形成的岩石发生深熔作用形成的。这一认识有助于了解华北地台南缘东段元古宙这一重要地质时期的地壳形成和演化。     

山东招远大尹格庄金矿控矿构造解析与找矿预测

[研究目的]大尹格庄金矿探明(金:283 t,银:397 t)发育于招平断裂带中段,矿区较大的断裂构造有4条:招平断裂、大尹格庄断裂、南周家断裂与南沟断裂,招平断裂带在矿区内呈NNE20°方向延伸,控制金矿体的形态、产状及发育部位.确定断裂构造的运动方向,可以指导大尹格庄金矿外围找矿预测.[研究方法]本文运用构造解析方...     

胶东玲珑金矿田171号脉深部金矿床特征及构造控矿作用

玲珑金矿田171号脉赋存于招平断裂北段破头青断裂中,在其深部探明金资源储量150余吨,确定其为超大型破碎带蚀变岩型金矿床。为了揭示构造与成矿、深部矿与浅部矿、石英脉型矿与蚀变岩型矿等的关系,为深部找矿提供典型实例和理论依据,文章通过大量矿区地质勘探、野外地质调查和区域地质综合研究,剖析了矿床特征,揭示了构造控矿规律。171号金矿脉深部共有7个金矿体,均为盲矿体。其中,171_1号主矿体埋深120~1700m,呈似层状、大脉状分布,沿走向及倾向显舒缓波状。矿体总体走向60°,倾向SE,倾角36.5~43.5°。矿体长2500m,斜深510~3100 m,平均厚度4.23 m,平均金品位2.71×10~(-6),矿石主要为黄铁绢英岩型(蚀变岩型)。矿脉和矿体受断裂构造控制,矿化、构造、蚀变分带具有一致性。由控矿断裂的主裂面至远离主裂面,构造变形强度由强变弱,蚀变强度和矿化强度也由强变弱。招平断裂是一条切割早期韧性剪切带的脆性断裂,总体呈舒缓波状展布,大部分地段发育于早前寒武纪变质岩系与侏罗纪玲珑型花岗岩之间,断裂上盘脆性变形较弱,下盘脆性变形带宽大,是沿不同时代地质体之间发育的左行铲式正断层,类似于拆离断层,是胶东白垩纪伸展构造的组成部分。玲珑金矿田是典型的石英脉型金矿产地,但大型金矿床多为赋存于断裂构造中的蚀变岩型金矿床,石英脉型金矿床与蚀变岩型金矿床是同一构造系统中不同构造位置的产物;一般在主断裂中赋存蚀变岩型金矿床,在主断裂下盘的次级张裂隙中产出石英脉型金矿床。胶东以正断层为主的伸展构造系统为大规模成矿提供了有利条件,构造、蚀变分带和不同类型金矿床的关系是金矿找矿的重要标志。     

胶东半岛烟台市域降水系列代表性分析

水资源量计算和设计洪水频率计算中采用不同系列年限的降水资料，会产生不同的计算结果。资料系列地代表性在计算中起到了相当重要的作用，结合烟台和青岛两站较长系列降水资料，用不同方法分析了系列的代表性，并提出了在实际应用中的修正方法。     

山东半岛"0512"持续暴雪分析

2005年12月山东半岛发生了持续暴雪天气过程，降雪量、积雪厚度及持续降雪历时都为山东半岛地区有水文资料以来第一位。雪灾所造成的损失也是历史最大，本文对这次持续暴雪的成因、特性、雪灾损失等进行初步分析。     

Nature and Evolution of Cenozoic Lithospheric Mantle beneath Shandong Peninsula,Sino-Korean Craton,Eastern China

The Shanwang and Qixia basalts lie within the North China block and were erupted in Miocene to Pliocene time (18.1 to 4.3 Ma) and Pliocene time (6.4 to 5.9 Ma), respectively. The Shanwang area lies astride the Tancheng-Lujiang (Tanlu) fault zone, a major lithospheric fault, whereas the Qixia area lies east of the fault zone. The basaltic rocks (alkali olivine basalts, basanites, nephelinites) carry abundant deep-seated xenoliths including spinel lherzolite (dominant), dunite, and pyroxenite, and a megacryst suite including augite, anorthoclase, phlogopite, ilmenite, and garnet. Xenoliths with coarse-grained microstructures are common in the Qixia xenolith suite, but are absent in Shanwang. Reconstructed bulk compositions of the lherzolites range from relatively depleted (<3% modal diopside) to fertile (>12% modal diopside). Equilibration temperatures of 850° to 1020°C indicate entrainment of these lherzolites from depths ≤45 km, within the lithosphere; the geotherm may have been higher beneath Shanwang. The Shanwang suite contains less-depleted lherzolites, and more pyroxenites, than the Qixia suite. The chondrite-normalized REE patterns in clinopyroxenes of the Shandong xenoliths vary from LREE depleted, through concave shaped, to LREE enriched; spidergrams for the clinopyroxenes can be divided into depleted, fertile, and metasomatic types. Progressive depletion in Na and Al is accompanied by depletion in moderately incompatible elements such as Y, Yb, and Zr, and an increase in Mg#. Ti and Zr in clinopyroxenes have not been affected by the metasomatic process, and MREE have been little disturbed, whereas the light rare-earth elements, Nb, and Sr have been strongly enriched during metasomatism; this suggests that carbonate-rich fluids/melts were the metasomatic agent. The mantle beneath the Shandong Peninsula sampled by these basalts is dominantly Phanerozoic in character rather than Archean or Proterozoic lithospheric mantle. This mantle probably represents a mixture of older lithospheric mantle and newly accreted material that replaced the Archean lithospheric keel through extension, thermal erosion, and fluid/melt metasomatism. The differences in micro-structures, chemistry, temperature, and fluid/melt activity between Shanwang and Qixia are ascribed to their spatial relationships to the Tanlu fault, which is a major translithospheric suture that hasplayed an important role in the Cenozoic replacement of the pre-existing Archean lithospheric mantle.     

胶东半岛牟平-即墨断裂带晚中生代运动学转换历史

牟平-即墨断裂带不仅构成了苏鲁造山带与胶北地块（华北地块）的边界,也是中国东部巨型郯庐走滑断裂系（即郯城-庐江走滑断裂系）的主要组成部分。基于野外断层滑动矢量分析和古构造应力场反演、侵入岩和火山岩锆石U-Pb离子探针和Ar-Ar测年分析,结合海域地球物理资料解释成果,研究了该断裂带平面展布形态和晚中生代构造演化历史。结果表明,牟平-即墨断裂带在晚侏罗世-白垩纪时期经历了挤压左旋平移引张伸展右旋走滑拉分等3个显著不同的运动学转变历史。晚侏罗世是重要的挤压作用时期,沿断裂带发生显著的左旋走滑活动,牟平-即墨断裂带东支桃村-东陡山断裂记录了约30km的左旋错移量。早白垩世时期,构造体制以引张伸展活动为主,引张应力方向为NW-SE至近W-E向,沿断裂带形成一系列深而狭长的断陷盆地;盆地中侵入岩和火山喷发岩锆石U-Pb离子探针和Ar-Ar测试,获得了一致的年龄在106～123Ma。晚白垩世古新世时期,断裂带以右旋走滑活动为主,右旋剪切拉分作用控制了胶县-莱阳伸展断陷盆地的发育,沿断裂带局部凹陷区控制了晚白垩世王氏群沉积。早、晚白垩世之间发生一期构造挤压事件,挤压方向NW-SE,导致断陷盆地构造反转和断裂带左旋走滑活动,但这期走滑位移量不大。牟平即墨断裂带运动学历史和构造应力场演化较完整地记录了中国东部晚中生代构造体制转换过程,并对构造体制转换过程的动力学背景提供了重要的构造地质学制约。     

Analysis of the ore-controlling structure of the Shihu gold deposit, Hebei Province and deep-seated ore-prospecting prediction

Under the guidance of the theory of mantle-branch structure-associated metallogenesis and on the basis of the geological characteristics, analysis of the ore-forming and ore-controlling structures, the geochemical characteristics of metallogenesis, the source of ore-forming materials, changes in the physical and chemical conditions of metallogenesis, changes in the vertical width of ore veins, and changes in gold grade of the Shihu gold deposit, the mechanism of its metallogenesis was discussed and the rules of vertical variation of ore veins were summarized in this study. It is pointed out that the orebodies under exploitation at present time should be in the middle and upper portions of gold veins in the Shihu gold mining district. Particularly on the basis of the characteristics of mantle-branch structure-associated metallogenesis, it is indicated that metallogenesis is controlled mainly by such ore-forming conditions as temperature and pressure. Deep-seated ore-forming fluids are characterized mainly by injection and precipitation. So the vein bodies in the adjacent metallogenic structures are of obvious comparability, and there would be great prospects for ore search both at depth and in the periphery of the Shihu gold deposit. Therefore, ore prospecting should be strengthened both at depth and in the peripheries.     

胶东牟平照岛山金矿蚀变矿化阶段及控矿要素

照岛山金矿位于胶东牟平-乳山成矿带北段,矿体产于中生代燕山期昆嵛山二长花岗岩中,主要受NNE向金牛山断裂带的控制。对金的成矿背景、矿床地质、控矿因素和矿体隐伏特征的研究结果表明：围岩蚀变从近矿到远矿依次发育黄铁绢英岩化、绢英岩化和钾长石化;金的成矿分为黄铁矿石英、石英黄铁矿、多金属硫化物、石英碳酸盐矿物4个阶段;昆嵛山岩体和荆山群变质岩的接触带附近易于成矿;金牛山主断裂走向NE的拐折地段、不同期次断裂交会处和多期断裂破碎带部位都易于成矿;金品位高值区呈近似等距分布,32线以南有向SW侧伏的趋势,40线以北有向NE侧伏的趋势。总结了照岛山金矿的控矿因素,初步推测了深部找矿方向。     

胶东牟平照岛山金矿蚀变矿化阶段及控矿要素

照岛山金矿位于胶东牟平-乳山成矿带北段,矿体产于中生代燕山期昆嵛山二长花岗岩中,主要受NNE向金牛山断裂带的控制。对金的成矿背景、矿床地质、控矿因素和矿体隐伏特征的研究结果表明:围岩蚀变从近矿到远矿依次发育黄铁绢英岩化、绢英岩化和钾长石化;金的成矿分为黄铁矿石英、石英黄铁矿、多金属硫化物、石英碳酸盐矿物4个阶段;昆嵛山岩体和荆山群变质岩的接触带附近易于成矿;金牛山主断裂走向NE的拐折地段、不同期次断裂交会处和多期断裂破碎带部位都易于成矿;金品位高值区呈近似等距分布,32线以南有向SW侧伏的趋势,40线以北有向NE侧伏的趋势。总结了照岛山金矿的控矿因素,初步推测了深部找矿方向。     

Enriched crustal and mantle components and the role of the lithosphere in generating Paleoproterozoic dyke swarms of the Ungava Peninsula,Canada

Paleoproterozoic mafic dyke swarms (2.5–2.0 Ga) of the Ungava Peninsula can be divided in three chemical groups. The main group has a wide range of Fe (10–18 wt.% Fe₂O₃) and Ti (0.8–2.0 wt.% TiO₂) contents, and the most magnesian samples have compositions consistent with melting of a fertile lherzolitic mantle at ~ 1.5 GPa. Dykes of a low-LREE (light rare earth element) subgroup (La/Yb ≤ 4) display decreasing Zr/Nb with increasing La/Yb ratios and positive εNd_2.0 Ga values (+ 3.9 to + 0.2) that trend from primitive mantle towards the composition of Paleoproterozoic alkaline rocks. In contrast, dykes of a high-LREE subgroup (La/Yb ≥4) display increasing Zr/Nb ratios and negative εNd_2.0 Ga values (? 2.3 to ? 6.4) that trend towards the composition of Archean crust. A low Fe–Ti group has low Fe (< 11 wt.% Fe₂O₃), Ti (< 0.8 wt.% TiO₂), high field strength elements (HFSE; < 6 ppm Nb) and heavy rare earth elements (HREE; < 2 ppm Yb) contents, but are enriched in large ion lithophile elements (LILE; K/Ti = 0.7–3) and LREE (La/Yb > 4). These dykes are interpreted as melts of a depleted harzburgitic mantle that has experienced metasomatic enrichment. A positive correlation of Zr/Nb ratio and La/Yb ratio, negative εNd_2.0 Ga values (? 14 to ? 6), and the presence of inherited Archean zircons further suggest the incorporation of a crustal component. A high Fe–Ti group has high Fe (> 14 wt.% Fe₂O₃) and Ti (> 1.4 wt.% TiO₂) contents, along with higher Na contents relative to the main group dykes. Dykes of a high-Al subgroup (> 12 wt.% Al₂O₃) share Fe contents, εNd_2.0 Ga values (? 2.3 to ? 3.4), La/Yb and Th/Nb ratios with Archean ferropicrites, and may represent evolved ferropicrite melts. A low-Al subgroup (< 12 wt.% Al₂O₃) has relatively lower Yb contents (< 2 ppm) and fractionated HREE patterns that indicate the presence of garnet in their melting residue. A comparison with ~ 5 GPa experimentally-derived melts suggests that these dykes may be derived from garnet-bearing pyroxenite or peridotite. The εNd_2.0 Ga values (? 0.3 to ? 2.0) of these dykes lie between the compositions of Archean granitoids and Paleoproterozoic alkaline rocks, signifying their petrogenesis involved both crustal and mantle components.Paleoproterozoic dykes containing a crustal component occur within, or close to, an isotopically enriched Archean terrane (T_DM 4.3–3.1 Ga), whereas dykes without this component occur in an isotopically juvenile terrane (T_DM < 3.1 Ga). The lack of a crustal component and the positive εNd_2.0 Ga values of dykes intruding the latter suggest that the crust they intruded was either too cold to be assimilated, or that its lower crust and/or lithosphere were Paleoproterozoic in age. In contrast, the ubiquitous presence of a crustal component and the diversity of mantle sources for dykes intruding the enriched terrane (lherzolite, harzburgite, pyroxenite) suggest a warmer crust with underlying heterogeneous lithospheric mantle.     

胶东招远-平度断裂地球物理异常特征及其控矿条件研究

招远-平度断裂是胶东金矿集区三条超大型控矿断裂（三山岛、焦家及招远-平度断裂）之一。受地表第四系覆盖影响,金矿体空间赋存位置与主断裂及其次级断裂地表出露位置的耦合关系尚存问题。通过开展精细化处理区域重力和航空磁测数据,如空间域不同高度延拓（100 m、200 m和500 m）及垂向一阶导数等方法,发现招远-平度断裂地表出露位置与深部地球物理梯度带存在位移差,且位移差向断裂倾向方向南东侧移动趋势愈发明显,进一步证明招远-平度断裂深部倾向南东,倾角由浅至深逐渐变缓,局部变化剧烈的地质推论。同时,开展地表高精度1/10000比例尺的重力结果显示,重力异常曲线自西向东整体呈快速上升趋势,局部存在凹陷区,表明花岗质碎裂岩及绢英岩化花岗质碎裂岩密度（2.63 g/cm3）介于玲珑二长花岗岩（2.57 g/cm3）和古元古界（2.82 g/cm3）之间,含矿层位与围岩存在较大密度差,金矿体主要赋存于花岗质碎裂岩及绢英岩化花岗质碎裂岩层位的倾角由陡变缓或由缓变陡的折部位,可分别发现石英脉型金矿和蚀变岩型金矿。     

山东半岛基性高压麻粒岩的成因矿物学及变质演化

在山东半岛的平度-莱西-莱阳-烟台一带,广泛出露基性高压麻粒岩,它们呈大小不等的透镜体或不规则脉状体产于TTG片麻岩中,且与超镁铁质岩石密切"伴生"。根据岩相学、矿物相转变、变质反应以及温压条件的系统研究结果,确定山东半岛基性高压麻粒岩经历了四个阶段的变质演化。早期进变质阶段(M1)的标志性矿物组合以石榴石及其内部的细粒单斜辉石+斜长石±石英为特征,记录的温压条件为T=740～770℃、P=0.9～1.0GPa;峰期高压麻粒岩相变质阶段(M2)的矿物组合以基质中石榴石(富Ca核部)+单斜辉石(富Al核部)+斜长石(富Na核部)±石英为特征,记录的温压条件为T=850～880℃、P=1.45～1.65GPa;峰后近等温减压(中压)麻粒岩相退变质阶段(M3),以发生一系列典型减压反应和斜方辉石的大量出现为标志,典型的矿物组合为斜方辉石+单斜辉石+斜长石+磁铁矿±角闪石,记录的温压条件为T=780～830℃、P=0.65～0.85GPa;晚期角闪岩相退变质阶段(M4)以石榴石发生降温反应、形成角闪石+斜长石+磁铁矿±石英等退变矿物组合为特征,记录的温压条件为T=590～650℃、P=0.62～0.82GPa。高压基性麻粒岩的变质演化的P-T轨迹具有顺时针型式,先后经历了近等温减压过程(ITD)和近等压降温过程(IBC)变质演化过程,指示研究区基性高压麻粒岩是古老陆块之间在俯冲-碰撞造山过程中加厚下地壳折返地表的产物。该项成果对于重新认识华北克拉通在早前寒武纪古老陆块的碰撞-拼贴及其演化的动力学过程具有重要科学意义。     

山东半岛早前寒武纪高级变质基底中超镁铁质岩的成因

山东半岛早前寒武纪高级变质基底广泛出露超镁铁质岩,它们呈大小不等的透镜体产于TTG片麻岩中,且与基性高压麻粒岩密切"伴生"。岩相学和矿物相转变分析、温压条件估算以及锆石原位U-Pb定年结果表明,山东半岛超镁铁质岩记录了十分复杂的演化历史,其中早期残留的原岩标志性的矿物组合 (M₁) 以尖晶石 (富Mg)+橄榄石 (富Mg)+斜方辉石 (富Mg) 为特征,相应的岩浆结晶温压条件T=980~1050℃、P=1.55~1.65GPa;峰期高压麻粒岩相变质阶段 (M₂) 的典型的矿物组合以尖晶石 (富Fe)+橄榄石 (富Fe)+斜方辉石 (富Fe) 为特征,相应的温压条件T=840~880℃、P=1.40~1.55GPa,此阶段形成的变质锆石记录的高压麻粒岩相变质时代为1858~1877Ma;峰后中低压角闪-麻粒岩岩相退变质阶段 (M₃) 的矿物组合以斜方辉石+单斜辉石+橄榄石+角闪石 (富 (Na+K))+尖晶石+磁铁矿(富Cr) 为特征,相应的温压条件T=760~820℃、P=0.55~0.65GPa,此阶段形成的变质锆石记录的退变质时代为1820~1840Ma;晚期低角闪岩相-绿片岩相变质阶段 (M₄),以形成角闪石 (贫 (Na+K))+磁铁矿 (贫Cr)+蛇纹石±绿泥石±金云母的矿物组合为特征,相应的温压条件T=500~600℃、P=0.32~0.40GPa。超镁铁质岩的变质演化具有典型碰撞造山带顺时针P-T-t轨迹,指示山东半岛超镁铁岩是古老陆块之间碰撞造山的产物。该项成果对于进一步深入探讨华北克拉通东南缘早前寒武纪古老陆块的碰撞-拼贴及其演化的动力学过程具有重要科学意义。     

南海复蘑菇状地幔低速柱结构及其地幔动力学

运用高分辨率天然地震面波层析成像和体波层析成像技术,研究东亚西太平洋地区及全球地幔三维速度结构时发现南海地区地幔存在深达2000km以上的巨型复蘑菇状地幔低速柱,结合地质、地球化学和地球物理相关标志,将复蘑菇状地幔低速柱称为南海复蘑菇状地幔柱。本文在论述南海复蘑菇状地幔柱的地质地球物理特征基础上,将地幔柱划分为柱头、柱体、柱尾、幔枝和热点等部分,建立起地幔柱三维几何结构模型,探讨了复蘑菇状地幔柱在南海海盆扩张过程中的主导作用以及欧亚板块、菲律宾海板块和印度洋板块相互作用对南海演化过程的影响。