基于ETM~+数据和GIS技术的缅甸铜金矿成矿预测     

独文惠  王功文  陈永清  郭娜娜  郝应龙  冯源 《地质通报》2015,34(4):786-791

在利用遥感数据和地理信息系统(GIS)技术的矿产资源勘查与评价中,矿化蚀变信息提取和构造信息提取起着至关重要的作用。以缅甸铜金矿为例,利用ETM+遥感图像,采用比值法、阈值分割和主成分分析(PCA)提取羟基蚀变信息;利用数字高程模型和遥感数据提取与铜金矿化有关的线环构造,结合地质资料和上述信息,利用证据权和分形方法进行整合,确定该研究区的成矿远景区。结果发现,已知铜金矿均分布于成矿靶区中,综合信息可为下一步的矿产资源勘探工作提供决策依据。  相似文献   

南海南部断裂的分形研究     

姚衍桃  詹文欢 《海洋通报(英文版)》2009,11(1):70-81

分形几何作为定量描述自然界中复杂非线性现象的强有力工具，将其应用于南海南部断裂体系的研究中，通过数盒子法计算了断裂分布的分维值。研究结果表明这种方法是可行的，断裂分布的分维值能有效地描述断裂的空间分布特征。南海南部断裂体系在标度区间25～250km内具有很好的统计自相似性，全部断裂的分维值为1．6601，北东向断裂的为1．3875，北西向断裂的为1．2693。根据断裂分维等值线，沿西南海盆扩张轴，两侧断裂呈对称展布；北东向的与北西向的在空间上有一定的互补性，这反映了两组断裂在发育过程中的相互制约性。结合南海的构造演化及南海南部油气盆地的分布，初步探讨了断裂分形特征与南海的构造演化及断裂分形特征与油气盆地分布之间的关系。  相似文献   

高挂山—牛头寨地区小型环形影象构造分析及其找矿意义     

钱惠林 《湖南地质》1989,8(2):18-22

高挂山—牛头寨地区,通过大比例尺航片解译,发现6个大小不等的小型环形影象信息。这些环形影象与岩浆活动、已知矿床、矿化点、重砂异常、物化探异常等的分布有着内在的联系。为预测找矿远景区和找隐伏矿床提供了影象依据。  相似文献   

Progressive metamorphism in a crustal-scale shear zone: an example from the Léon region, north-west Brittany, France     

K. A. JONES 《Journal of Metamorphic Geology》1994,12(1):69-88

This paper describes the progressive metamorphism and deformation of a series of metasediments, Le Conquet Schists and their higher grade equivalents, which occur as tectonically emplaced screens within a sequence of foliated gneisses, the Gneiss de Brest and Gneiss de Lesneven. The sequence exhibits a steep south to north increase in metamorphic grade from garnet-staurolite schist to sillimanite gneiss and sillimanite-K-feldspar migmatite. The relationship of mineral growth to foliation development has been established for individual screens. At least five phases of deformation (D1-D5) are preserved. Analysis of porphyroblast inclusion trails is used to demonstrate sequential mineral growth during the successive development of orthogonal foliations S1-S4. Porphyroblasts continued to grow during the subsequent development of C-S mylonite fabrics and extensional crenulation cleavages which are genetically related to a series of high-strain zones (D5). Mineral assemblages, phase relations and mineral chemistry are consistent with porphyroblast growth being the result of continuous reactions. Microstructure-porphyroblast relations are used to show that although mineral growth proceeded during continuous reactions, these only operated episodically. Phase relations, mineral chemistry and P-T estimates are used to constrain P-T trajectories and these are linked to the deformation histories within individual screens. A comparison between the resulting pressure-temperature-deformation paths is used to demonstrate that the metamorphic peak occurred progressively later and at successively lower pressures with increasing metamorphic grade. It is suggested that the early evolution of the belt is the result of crustal thickening by overthrusting. The subsequent history is one of progressive heating and unroofing of the higher grade rocks in a dextral strike-slip transtensional shear zone.  相似文献   

推覆构造的特征及其与油气的关系     

汤锡元 《地球科学与环境学报》1988,(2)

推覆构造是地壳中广泛发育的一种构造型式。逆冲断层常成带地平行排列,形成逆冲带和叠瓦构造。断层多呈上陡下缓或阶梯状,底部常有滑脱构造,并在深处常收敛在一个基底逆冲断层上。推覆构造还常与飞来峰、构造窗、叠瓦构造、牵引褶皱、后冲断层和平移断层等构造现象一起产出。推覆构造不仅扩大了找油的领域,它本身对油气的生成、储集、运移、圈闭和保存条件都有着重要的影响。虽然它们有时可造成某些对油气藏不利的因素,但更经常地则是造成油气藏形成的有利条件。当然,影响油气藏形成的因素十分广泛,它不仅限于推覆构造本身的某些特征,同时还决定于许多其它地质条件。因此,不同推覆构造或同一推覆构造的不同部位,其含油气远景也是很不相同的。  相似文献   

Transverse structures in the central part of the Red Sea and implications on early stages of oceanic accretion     

A. Y. Izzeldin 《Geophysical Journal International》1989,96(1):117-129

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Plate tectonics at an awkward junction: rules for the evolution of Sovanco Ridge area, NE Pacific     

C. R. B. Lister 《Geophysical Journal International》1989,96(2):191-201

Summary. The elegant geometrical rules of plate tectonics do not allow for a gradual shift in plate motion directions, or the gradual, as opposed to sudden, cessation of subduction. At the scale of the small plates in the NE Pacific, imperfections in boundary processes have a large effect on the net torque on the plates, and heavily influence the evolution of the geometry. In this area, the rotation of the spreading directions and the diminution of true subduction along the southern Canadian coast has not occurred by the sudden switching of plate motions from one stable condition to another. Instead, it appears as if the dominant factor for the evolution is the resistance of the ocean floor to formation of new, smoothly slipping transform faults. Compressive deformation of even young lithosphere is not only mechanically unlikely, but is not helpful to the particular configurations found in this area. Instead, a migrating shear zone and an episode of highly en echelon spreading along a new axis nearly perpendicular to the present Juan de Fuca ridge have resulted: the present Sovanco ridge was never a transform fault. Neither is the Nootka fault a shear zone, but the locus of stretching between plates whose motions are congruent at the Juan de Fuca ridge, but diverge toward the continental margin.  相似文献   

汶川地震区北西向断裂带遥感分析   总被引：1，自引：0，他引：1  

魏成阶  杨攀新  张俊  刘亚岚  阎守邕 《遥感学报》2012,16(5):1054-1073

利用北京一号小卫星遥感影像判读汶川地震区的断裂构造,发现了一系列100km左右等间距排列的北西向断裂,结果已部分地得到实地考察验证。龙门山断裂与北西向断裂的交汇部位发生强烈地震的几率较高。这些新发现将对汶川Ms8.0级地震发生机理、龙门山断裂带活动性分段、断裂同震位移自南西向北东、由右旋走滑逆断层向右旋走滑断层转变等重大问题提供了新的合理解释。  相似文献   

Structural controls on fractured coal reservoirs in the southern Appalachian Black Warrior foreland basin   总被引：1，自引：0，他引：1  

Richard H. Groshong Jr.  Jack C. Pashin  Marcella R. McIntyre 《Journal of Structural Geology》2009,31(9):874

Coal is a nearly impermeable rock type for which the production of fluids requires the presence of open fractures. Basin-wide controls on the fractured coal reservoirs of the Black Warrior foreland basin are demonstrated by the variability of maximum production rates from coalbed methane wells. Reservoir behavior depends on distance from the thrust front. Far from the thrust front, normal faults are barriers to fluid migration and compartmentalize the reservoirs. Close to the thrust front, rates are enhanced along some normal faults, and a new trend is developed. The two trends have the geometry of conjugate strike-slip faults with the same σ₁ direction as the Appalachian fold-thrust belt and are inferred to be the result of late pure-shear deformation of the foreland. Face cleat causes significant permeability anisotropy in some shallow coal seams but does not produce a map-scale production trend.  相似文献   

Overprinted strike-slip deformation in the southern Valley and Ridge in Pennsylvania     

Richard P. Nickelsen   《Journal of Structural Geology》2009,31(9):865

Two major faults, over 32 km long and 6.4 km apart, truncate or overprint most previous folds and faults as they trend more northerly than the previous N25°E to N40°E fold trends. The faults were imposed as the last event in a region undergoing sequential counter-clockwise generation of tectonic structures. The western Big Cove anticline has an early NW verging thrust fault that emplaces resistant rocks on its NW limb. A 16 km overprint by the Cove Fault is manifested as 30 small northeast striking right-lateral strike-slip faults. This suggests major left-lateral strike-slip separation on the Cove Fault, but steep, dip-slip separation also occurs. From south to north the Cove Fault passes from SE dipping beds within the Big Cove anticline, to the vertical beds of the NW limb. Then it crosses four extended, separated, Tuscarora blocks along the ridge, brings Cambro-Ordovician carbonates against Devonian beds, and initiates the zone of overprinted right-lateral faults. Finally, it deflects the Lat 40°N fault zone as it crosses to the next major anticline to the northwest. To the east, the major Path Valley Fault rotates and overprints the earlier Carrick Valley thrust. The Path Valley Fault and Cove Fault may be Mesozoic in age, based upon fault fabrics and overprinting on the east–west Lat 40°N faults.  相似文献