黑龙江某铜矿床原生异常特征及评价标志

矿田位于阿尔山—多宝山复背斜,窝理河复式背斜的北西向帚状构造带上。区域北东向的褶皱、断裂发育。在北西向褶皱、断裂、片理化带组成的构造带与北东向或北北东的断裂交叉时,矿化较好,可形成斑岩型铜矿床。     

甘肃省宕昌县代家庄铅锌矿的发现 及物探化探找矿效果

甘肃省宕昌县代家庄铅锌矿床以氧化矿石为主,矿体赋存在浅海台地相、生物礁滩相形成的生物碎屑灰岩、硅质岩中,受北西向张扭性断裂及其次级断裂的控制;区內岩(矿)石电性差异较显著,圈定的激电异常呈北西向带状展布,与以Pb、Zn、Ag、As、Sb、Au、Hg等为组合特征的土壤地球化学异常、矿化构造带吻合,通过分析物、化探异常发现了矿体;提出了地质—地球物理—地球化学综合找矿标志。     

广西摩天岭地区拉培地段铀成矿构造体系研究及成矿潜力分析

为指导摩天岭地区北部拉培地段铀矿找矿工作,文章在前人区域构造体系研究基础上,通过对断裂构造走向、规模、活动期次和断裂充填物类型的详细调查分析,梳理了构造体系,划分了成矿期构造活动期次,应用里德尔剪切模型研究了成矿期构造运动学规律和动力学演化特征,最后分析了各构造带铀成矿潜力。文章将拉培地段构造体系划分为4组：北东向乌指山断裂、北西向断裂、近东西向断裂和北东向羽状断裂。矿前期,在伸展构造体制下,研究区构造应力场主要以张性为主,乌指山断裂活化;成矿期转变为左行走滑体制,与乌指山断裂配套形成了以F20为代表的北西向张性T断裂和以F6为代表的近东西向反向剪切断裂;成矿中-晚阶段,随着剪切作用的不断进行,新生了一组与乌指山断裂呈小角度相交的北东向左行压扭性P断裂,北西向断裂由张性转变为右行剪切,而近东西向断裂压性特点更加显著;矿后期,研究区基本结束左行走滑体制,转为东西向拉张作用。北东向乌指山断裂是研究区内重要的导矿构造,断裂本身成矿潜力一般;北西向断裂整体成矿潜力一般,但与北东向断裂交汇部位往往为重要的铀成矿地段,应引起重视;近东西向断裂成矿期活动强烈,成矿作用明显,成矿潜力好;北东向羽状断裂...     

西秦岭夏河-合作地区断裂构造分形结构特征及成矿预测

西秦岭夏河-合作地区是中国重要的金矿及多金属矿床开发地带,区内断裂构造复杂,构造控矿作用显著。文章利用分形理论方法对夏河-合作地区不同方向断裂构造作定量分析,统计计算断裂构造容量维和信息维,结合矿床空间分布分形特征和矿床Fry分析,探讨研究区构造分形特征及断裂与矿床的空间展布关系。研究结果表明,研究区全部断裂容量维1.2374,北东向断裂容量维0.8229,北西向断裂容量维1.2296,近东西向断裂容量维1.0312,全部断裂容量和北西向断裂容量维处于断裂分形临界值（1.22~1.38）区域,显示研究区断裂构造连通性较好。研究区全部断裂信息维1.1118,北东向断裂信息维1.018,北西向断裂信息维1.2296,近东西向断裂信息维1.0217,北西向断裂信息维处于断裂分形临界值区域,反映北西向对矿床的控制最强。断裂构造分形维数可以表征矿床的沉积部位,以容量维、信息维等值线图以及Fry图划分出3个有利成矿区。     

中国大陆东部新构造期北西向断裂带的初步探讨

前人对中国大陆东部新构造期 (N—Q)活动的北东向断裂 (带 )已有很多研究。笔者根据地震构造、新构造和火山活动等资料并结合Pn波速结构研究结果 ,分析了该区新构造期的北西向活动断裂 ,初步得出 :北西向断裂具有成带性 ,可分 7条北西向断裂带 ;它们有鲜明的新生性 ;均为地壳构造带 ;与北东向断裂带呈共轭关系 ,是在先存构造基础上于新构造应力场作用下正在发育的一套地壳共轭剪切破裂系统。     

江西盛源盆地基本地质特征

盛源盆地是我国一个重要产铀盆地;盆地构造以断裂为主;早白垩世末的北东向、北西向断裂导致了盆地的形成,晚白垩世后的北北东向断裂使盆地发生形变。     

鲁西北西向断裂系晚中生代活动的几何学、运动学及年代学研究

鲁西隆起区发育有大量的北西向脆性断裂。依据野外断裂构造的几何学、运动学详细解析认为,北西向断裂系经历了早期的右行压剪、右行张剪,以及后期的左行压剪等不同性质的构造活动。由与北西向断裂活动相伴生的同期侵入岩体的 K-Ar测试结果分析,北西向断裂系在距今约160 Ma及距今130~110 Ma分别经历了右行压剪与右行张剪构造活动;通过分布在隆起区不同样品的磷灰石裂变径迹数据分析、冷却史反演,厘定鲁西地体在距今90~80 Ma存在一次区域性快速冷却构造事件,该构造事件与北西向断裂系的左行压剪构造活动相对应。     

东营凹陷中生代原型盆地恢复及其演化

综合利用三维地震、测井及地球化学等资料,详细解剖断裂体系的静态和动态发育特征;运用多种剥蚀量恢复方法,求取侏罗系、白垩系及中生界剥蚀厚度,对东营凹陷中生代原型盆地格局进行恢复。研究结果表明：中生代活动的北西向断裂构成了该时期的控盆断裂体系,包括石村—平南—滨西断层,陈南断层东段两个主断裂带及王古1断层、王66断层、滨南断层等次级断裂,形成了北断南超的断陷盆地。原始地层沉积由石村—平南—滨西断层分隔,形成东、西两个沉积区,由次级断裂控制形成多个次级沉积区。东营凹陷原型盆地特征与现今盆地格局具有较大差异,整体为东、西两个主洼,东部主洼受陈南断层东段控制,次级北西向断层分割成多个次洼,呈现“盆岭相间”的格局;西部主洼由石村—平南断层控制,沉积中心位于青城凸起及花沟洼陷;该时期平方王潜山、纯化草桥鼻状构造带已经形成,林樊家凸起和青城凸起尚未形成。     

鲁西北西向断裂系晚中生代活动的几何学、运动学及年代学研究

鲁西隆起区发育有大量的北西向脆性断裂.依据野外断裂构造的几何学、运动学详细解析,认为北西向断裂系经历了早期的右行压剪、右行张剪,以及后期的左行压剪等不同性质的构造活动.由与北西向断裂活动相伴生的同期侵入岩体的 K-Ar测试结果分析,北西向断裂系在距今约160 Ma及距今130～110 Ma分别经历了右行压剪与右行张剪构造活动;通过分布在隆起区不同样品的磷灰石裂变径迹数据分析、冷却史反演,厘定鲁西地体在距今90～80 Ma存在一次区域性快速冷却构造事件,该构造事件与北西向断裂系的左行压剪构造活动相对应.     

首都圈地区小震重新定位及其在地震构造研究中的应用

使用双差地震定位法对首都圈地区39°～4 1°N,115°～118°E范围内1980～2 0 0 0年的2 0 98个小震进行了重新定位,定位均方根残差从重新定位前的1.4 s降到0 .32 s。重新定位后,地震活动多集中分布于北东与北西向断裂的交汇处,或密集成北东与北西向线性分布,与已知活动断裂具有密切的关系。在顺义与延怀盆地一带揭示出几条高角度北西向隐伏活动断裂,长度在10～2 0 km间。小震活动显示的构造信息表明,北西向构造是重要的发震构造,在现今构造变形和地震孕育、发生中,与北东向构造起着同样重要的作用。同时,重定位震源深度分布在东西方向上显示出明显的不均匀性,推测是地壳变形和构造活动强弱在横向变化的一种反映。     

鄂尔多斯盆地南缘重磁场特征及其与砂岩型铀矿关系

鄂尔多斯盆地南部是我国重要的砂岩型铀矿产地之一。为了研究该区重磁场特征与砂岩型铀矿展布规律的关系,预测砂岩型铀矿有利区,本文在对鄂尔多斯盆地南缘重、磁资料处理与解释的基础上,推断了研究区的断裂构造,探讨了断裂构造、重磁场平面特征与已知铀矿点的关系,预测了铀矿成矿有利区。研究结果表明:研究区发育的断裂走向有NE向、近EW向、近SN向和NW向4组;已知铀矿(床)点多分布于断裂与次级断裂交汇处,重力梯级带、局部重力高边缘和磁力中低缓异常区。研究区有平凉、宜君-黄陵、彬县-旬邑3个铀矿有利成矿区。     

Geophysical prospecting of copper-nickel deposits in Beishan rift zone,Xinjiang

The Beishan rift zone in Xinjiang Uygur Autonomous Region was formed due to strong activities of faults on the basement of the Tarim continental crust. Despite the fact that many geological research results of the rift zone have been achieved, only a few studies have been conducted on its regional geophysical characteristics. In this paper, the gravity and magnetic anomalies of the rift zone were highlighted through specific data processing of 1:50000 high-precision aeromagnetic data and gravity data with a grid spacing of 2 km × 2 km. Based on this, the geophysical evidence for the scope and internal structures of the Beishan rift zone was obtained for the first time. The distinct characteristics of magnetic and gravity fields in the areas to the north and south of the Beishan rift zone reveal that deep faults exist between the Beishan rift zone and the geological units on the southern and northern sides. Furthermore, the faults on the two areas contain the bidirectional thrusts and have flower-shaped structures according to the characteristics of the magnetic and gravity fields. The Beishan rift zone can be divided into two tectonomagmatic zones, namely the Zhongposhan-Bijiashan-Cihai-Baishanliang zone (the northern zone) and the Bayiquan-Qixin-Baishan zone (the southern zone). The northern zone can be further subdivided into three comet-shaped anomaly groups (tectonomagmatic areas), while the southern zone can be further subdivided into two tectonomagmatic areas. According to the characteristics of aeromagnetic anomalies and gravity field, 19 mafic-ultramafic complexes were delineated. The known Pobei, Hongshishan, and Qixin complexes are all located within the inferred complexes, with estimates of total explored resources of Ni, Cu, and Au of 3×10⁶ t, 10×10³ t and 10 t, respectively. The prospecting of high-grade copper-nickel deposits should focus on the periphery and deep parts of the known and inferred mafic-ultramafic complexes. Among them, the peripheral strata of the complexes specifically have great prospecting potential of large-scale high-grade copper-nickel deposits of magma injection type. Finally, this paper analyzed the application effects of the rapid airborne-ground-drilling synergetic exploration method in the prospecting of copper-nickel deposits in Qixin, Beishan, Xinjiang, which will provide references for further exploration of copper-nickel deposits in Beishan area, Xinjiang.©2021 China Geology Editorial Office.     

西藏谷露地热田地热资源前景及勘探方向

西藏亚东-谷露裂谷带是新生代的活动构造带,具有构造活跃、地震频繁、热泉广布、大地热流高等特征,孕育了丰富的地热资源。已实现商业开发多年的羊八井地热田和羊易地热田正是位于亚东-谷露裂谷带的中部,而位于该构造带北部的谷露地热田地热资源前景和勘探方向还有待深入认识。为此,本文解析了地表地热构造,对比了羊八井地热模式,分析了谷露地热田的深部热动力学背景,并结合钻井试采资料揭示谷露地热田具有良好的地热资源前景。在此基础上,利用大地电磁和重力预测了谷露地热田的地热分布具有南北分带性,即北部和中部具有深部和浅部两个层次的地热储层,而南部地热储层则以浅部为主。为深入研究亚东-谷露裂谷带的地热系统模式及指导地热勘探开发提供了重要的地球物理依据。     

Rheological gravity model of the crust and upper mantle of Transbaikalia

Based on rheological interpretation of formalized gravity models, earlier known deep-seated structures in the Earth’s crust and mantle of Transbaikalia have been detailed and new ones discovered. The structures are asymmetric and transverse relative to the Baikal rift zone. Their presence explains the peculiar features of the Baikal rift, including the one-way southeasterly direction of horizontal displacement of tectonic masses and northwestern migration of the Earth’s crust extension processes. The prolonged history (more than 250 Ma) of the Baikal rift zone and Transbaikalia mountainous country involved gravity or rotational detachments of rigid tectonic slabs from the craton and their sliding along intracrustal and subcrustal decollement zones into the above-dome area of the Transbaikalia asthenolith.     

东北地区北西向构造的成因与特征

通过对以往重磁数据重新处理,对以往不被人们关注,至少是少为人们关注的东北地区北西向构造有了新的认识.研究认为：东北地区北西向构造不仅大规模存在,而且还对东北地区的地质构造格架、东北地区的矿产资源的产出与分布都有着不可忽视的作用.讨论了北西向构造在重磁场上证据以及北西向构造的地质应力条件,证明北西向构造晚于北东向、北北东向构造,是一组独立的构造体系.     

冀西北地区重力场特征及对地质构造的再认识

依据冀北地区1:20万区域重力调查成果,阐述了冀西北地区区域重力场的基本特征,在对该地区断裂构造推断解释的基础上,提出了对该区主要构造的新认识.其中依据重力资料新推断出3条北西向断裂构造:康保-赤城-密云断裂F₁₁、张北-张家口-怀来-昌平断裂F₄₇、万全榆树林-涿鹿倒拉咀断裂F₄₈;认为东西向康保-沽源、崇礼-赤城、天镇-密云深大断裂带,北东向张北-沽源、怀来-上黄旗、北西向兰城子-龙门所、张北-沙河、榆林沟-南流水断裂带构成了本区内深部断裂的构造格架.     

Application of Bi-dimensional empirical mode decomposition (BEMD) modeling for extracting gravity anomaly indicating the ore-controlling geological architectures and granites in the Gejiu tin-copper polymetallic ore field,southwestern China

The Gejiu tin-copper polymetallic ore field, located at the westernmost end of the Cathaysia Block in South China, is one of the largest tin polymetallic ore fields in the world. It is associated with magmatic-hydrothermal ore-forming processes triggered by deeply seated structures and concealed granites. The Bi-dimensional empirical mode decomposition (BEMD) was used to decompose gravity data covering an area including the Gejiu tin-copper polymetallic ore field in the west and the Bozhushan silver-lead-zinc polymetallic ore field in the east, which yielded three two-dimensional intrinsic mode function (BIMFs) images and one residue (Res(m, n)) image that depict four layers of geological architectures at different wavelengths within the study area. The high-pass filtered gravity component image (BIMF₁) is interpreted to depict the shallow geological architecture, which indicates that the skarn alteration and tin-copper mineralization with positive gravity anomalies are distributed around the granites characterized by negative gravity anomalies. The band-pass filtered gravity component image (BIMF₂) is interpreted to depict the middle-shallow geological architecture, which indicates that the outcropped granites in the western Gejiu ore field bounded by the Gejiu fault may extend to the eastern Gejiu ore field to form one integrated granitic complex in the subsurface. The other band-pass filtered gravity component image (BIMF₃) is interpreted to depict the middle-lower geological architecture, which indicates that there may be an EW-trending granite zone with negative gravity anomaly at middle-lower depth connecting the Gejiu tin-copper polymetallic field to the Bozhushan silver-lead-zinc polymetallic field, displaying the existence of an EW-trending regional polymetallic ore-forming zone within the study area. The low-pass filtered gravity component image (Res(m, n)) is interpreted to depict the lowest geological architecture within the study area, which reflects that there may be a pair of the NW-trending uplift zone of the mantle and/or the basement with positive gravity anomaly and the depression zone of the mantle and/or the basement with negative gravity anomaly. The Gejiu tin-copper polymetallic deposits and the related granites are located at the transitional zone between the uplift and depression, whereas the Bozhushan silver-lead-zinc polymetallic deposits and the related granites are situated within the depression zone, which implies that the diversity of the Late Yanshanian granites and the related polymetallic deposits in the study area may be controlled by the complexity of the crust-mantle interaction at depth.     

The Baikal rift zone: the effect of mantle plumes on older structure

The main chain of SW–NE-striking Cenozoic half-grabens of the Baikal rift zone (BRZ) follows the frontal parts of Early Paleozoic thrusts, which have northwestern and northern vergency. Most of the large rift half-grabens are bounded by normal faults at the northwestern and northern sides. We suggest that the rift basins were formed as a result of transformation of ancient thrusts into normal listric faults during Cenozoic extension.Seismic velocities in the uppermost mantle beneath the whole rift zone are less than those in the mantle beneath the platform. This suggests thinning of the lithosphere under the rift zone by asthenosphere upwarp. The geometry of this upwarp and the southeastward spread of its material control the crustal extension in the rift zone. This NW–SE extension cannot be blocked by SW–NE compression generated by pressure from the Indian lithospheric block against Central Asia.The geochemical and isotopic data from Late Cenozoic volcanics suggest that the hot material in the asthenospheric upwarp is probably provided by mantle plumes. To distinguish and locate these plumes, we use regional isostatic gravity anomalies, calculated under the assumption that topography is only partially compensated by Moho depth variations. Variations of the lithosphere–asthenosphere discontinuity depth play a significant role in isostatic compensation. We construct three-dimensional gravity models of the plume tails. The results of this analysis of the gravity field are in agreement with the seismic data: the group velocities of long-period Rayleigh waves are reduced in the areas where most of the recognized plumes are located, and azimuthal seismic anisotropy shows that these plumes influence the flow directions in the mantle above their tails.The Baikal rift formation, like the Kenya, Rio Grande, and Rhine continental rifts [Achauer, U., Granet, M., 1997. Complexity of continental rifts as revealed by seismic tomography and gravity modeling. In: Jacob, A.W.B., Delvaux, D., Khan, M.A. (Eds.), Lithosphere Structure, Evolution and Sedimentation in Continental Rifts. Proceedings of the IGCP 400 Meeting, Dublin, March 20–22, 1997. Institute of Advanced Studies, Dublin, pp. 161–171], is controlled by the three following factors: (i) mantle plumes, (ii) older (prerift) linear lithosphere structures favorably positioned relative to the plumes, and (iii) favorable orientation of the far-field forces.     

苏丹东北部哈维特金矿地质特征及控矿构造研究北大核心CSCD

哈维特金矿床位于阿拉伯-努比亚地盾Gabgaba地块,是苏丹东北部近年来新发现的一个金矿床。通过系统的野外地质调查和控矿构造研究,初步揭示了该矿床的地质特征及矿床类型,基本查明了矿区的构造特点及其含矿性,为矿区进一步勘查指明了方向。该矿区金矿(化)体呈脉状,严格受NW向脆-韧性剪切带控制,产于低绿片岩相的片理化带内,主要以含金硅化碳酸盐化黄铁矿化绢英岩或碎裂岩的形式产出。硅化、黄铁矿化、碳酸盐化和绢云母化与金成矿关系密切。就矿床成因类型而言,应属于造山型金矿床。综合分析矿区构造特征发现,矿区脆-韧性剪切带具左行特征,其内广泛发育NW、NE、NEE、NNW、NNE向断裂构造;NW向左行左列断裂、NE向右行左列断裂和NEE向右行断裂是本区最主要的含矿构造,而NNW、NNE向断裂多为成矿期后的断裂构造;矿区构造形成演化过程中,先后经历了挤压变形、后挤压和伸展作用三个阶段,金成矿作用主要形成于后挤压作用阶段。矿区今后勘查找矿工作应重点针对NW向、NE向断裂构造控制的金矿体展开。     

Evidence for and relationship between recent distributed extension and halokinesis in the Farasan Islands,southern Red Sea,Saudi Arabia

This paper presents a structural evolution study of the Farasan Bank using an integration of field work, remote sensing data, and regional Bouguer gravity data interpretation. The architecture of the Farasan Islands is influenced by normal faults parallel to the Red Sea rift axis delineating a series of graben and asymmetric half-graben structures as well as salt domes. Geological data suggest that the negative gravity anomaly over the Farasan Bank reflects thick salt deposits. The gravity data shows a general NW-SE trend with the main negative anomaly coincident with the Farasan Islands. Gravity data together with seismic reflection data suggest that salt diapirs are elongated and parallel to the main rift orientation (NW-SE). This indicates that salt deposition and diapirism was controlled by rift-related basement structures. Forward modeling of gravity data constrained by marine seismic reflection interpretation reveals that the evaporites directly overlie the basement in most places. No pre-evaporite formation was detected. Integration of the modeling with field observations and interpretations suggests that the Farasan Islands are in an area of active extension. Extension and salt diapirism on the flank of the mid-ocean ridge is likely to be synchronous with renewed spreading at 5 Ma.