用重力三方向小子域滤波解释伊通盆地断裂

关于伊通盆地的断裂系统, 前人主要研究了边界断裂和盆地内的2号断裂的性质.为了精细地解译盆地内其他断裂的基本性质, 利用重力场小子域滤波及三方向小子域滤波技术圈定了14条断裂的平面位置, 给出了伊通盆地平面断裂构造格架并描述了主要断裂的重力场特征.在与其他地球物理资料(4条地震剖面和4条电阻率断面) 的对比分析中, 除证实了已有的断裂外, 还验证了利用三方向小子域滤波技术最新发现的一些断裂, 证明了该方法技术的有效性.阐述了14条断裂的基本性质, 重点研究了盆地内中央断裂的存在性和基本性质.指出中央断裂是与盆地东南缘和西北缘两条断裂同期形成的主要控盆构造; 2号断裂向西与西拉木伦断裂相连, 盆地南部(2号断裂以南) 基底与华北板块有关, 北部则属于东北微陆块复合基底.      

基于航空重磁特征对突泉盆地构造的认识

为获取突泉盆地航空物探基础地质资料,为油气调查评价提供参考,中国国土资源航空物探遥感中心在该盆地开展了1:10万航空重磁综合调查工作。利用最新的航空重磁资料及实测岩石物性数据,对突泉盆地及其邻区重磁异常特征进行研究,分析航空重磁异常与地层展布、断裂活动、岩浆岩体的分布关系,重点探讨盆地的基底性质。结果表明,研究区航空重力异常与航磁异常在强度、范围、形态、梯度和走向等方面具有一定的规律性,该区断裂体系分布与重磁场特征明显相关,NNE-NE向、NW向及NE向3组断裂明显控制盆地沉积岩体及岩浆岩体的展布,盆地基底由下古生界浅变质岩系和前古生界中等变质岩系构成。     

鄂尔多斯盆地东南部重磁场特征及其氦气勘探意义

氦气作为一种稀有气体,广泛应用于国防军工、高新技术产业发展等领域,关系到国家的安全与发展。中国氦气资源短缺,对外依赖程度高。鄂尔多斯盆地内展现出了较好的氦气资源前景,但对与氦气分布密切相关的氦源岩及断裂特征研究较少,制约了对盆地氦气资源潜力的认识。笔者利用归一化总水平导数垂向导数（NVDR−THDR）、垂向导数、位场分离等技术对鄂尔多斯盆地东南部的重磁资料进行处理,推断主要断裂和潜在的氦源岩（强磁性变质岩）。鄂尔多斯盆地东南部氦气分布受基底断裂与氦源岩分布的双重控制,基底强磁性变质岩为盆地内部的氦气富集提供气源条件,断裂活动则为氦气运移提供通道。富县−宜川−黄龙一带分布有大量的强磁性变质岩,大多位于断裂附近及其交汇区域,可能是氦气资源潜在有利区。     

大地电磁测深在下扬子及邻区的应用

全面分析、对比了下扬子及邻区电性层与电性特征。下扬子盆地与周边构造单元的边界及接触关系的研究表明,下扬子盆地基本上为东西对冲结构,东与西均以推覆带形式相接触。建立了下扬子地区岩石圈的层块结构,其特点是各层系间在横向上为隆(薄块)坳(厚块)相间,纵向上为隆坳交替。发现了四条岩石圈级深大断裂,特别是大别—舟山断裂与滨海—桐庐隐伏深断裂是近期研究所得。首次编制出海相中—古生界残留厚度图,并发现了变质岩推覆带下海相中—古生界新领域及火山岩覆盖下海相中—古生界新领域,这些成果为下扬子地区寻找海相油气藏开辟了新的方向。     

藏北羌塘盆地构造特征及演化

羌塘盆地基底由元古宙变质岩系组成，具双层结构，下部为结晶“硬基底”、上部为变质“软基底”；构造上具两坳夹－隆和断凸断凹特征。盆地盖层由中泥盆统至第三系组成，主要为海相碳酸盐岩和碎屑屑岩及白垩系、第三系陆相砂、砾岩。盖层中变形强烈，发育多组褶皱、断裂。在变形在平面上方向性、分带性、等距性明显；在剖面上具差异性、不协调性。盆地主要变形期为燕山期－喜马拉雅期。     

沅麻盆地白垩系地层层序及盆地演化

沅麻盆地地层层序复杂,可划分为４个层序。盆地基底由晚元古代低级变质岩系组成的复式向斜变带主体构成,代表了加里东期变形图象。晚白垩纪后,构造变形表现为一系列重新活动的基底断裂和新生断裂、褶皱构造简单。通过沉积特征、地层层序、构造运动等研究、盆地演化可分张焰、稳定４个阶段。     

长江中下游宁芜火山岩盆地深部结构特征——来自反射地震的认识

宁芜火山岩盆地是长江中下游成矿带的重要组成部分,盆地内广泛产出玢岩型铁矿床。为探讨宁芜火山岩盆地深部结构,作者完成了三条穿越宁芜火山岩盆地的深反射地震剖面。三条剖面的长度不一,NW01剖面长度42km,NW02长56.3km,NW03长27.1km。三条剖面的排列长度都为720道,采样间隔2ms,记录长度16s。因为本文的主要研究对象是宁芜火山岩盆地上地壳的结构特征,因此只用了总记录长度的前4s数据。通过本次研究揭示了宁芜矿集区的上地壳精细结构、岩浆和断裂系统的空间展布形态。不仅验证了以往对盆地的部分认识,而且给出了新的认识。(1)发现了直接控制盆地火山-岩浆活动的南东和北西边界断裂并非人们经常认为的两大基底深断裂:方山-南陵断裂和长江断裂带,而是北西向F1和南东向F2断裂;(2)宁芜火山岩盆地以马鞍山-薛津断裂为界向北北东方向滑脱,造成了盆地南西高北东低的隆凹构造格局;(3)阐明了就位于盆地下方的为火山-岩浆活动提供补给和热源的岩浆房的空间展布特征;(4)清晰地厘定了盆地内的断裂系统,其中最主要的断裂是隐伏于宁芜火山岩盆地深部的控制深部岩浆活动的盆中基底断裂(BCF),控制着深部岩浆岩的空间展布格局并对宁芜火山岩盆地的地层和断裂系统有强烈地改造作用。本文的发现为宁芜火山岩盆地深部结构认识、成矿预测及成矿动力学分析提供了可借鉴的证据。     

重磁电综合地球物理探测河套盆地深部结构

从地球物理的角度出发,利用重力、磁法及电法勘探对河套盆地第四系深覆盖区展开深入研究,对河套断陷带南北边界断裂——鄂尔多斯北界断裂、色尔腾山前断裂的性质,河套盆地第四纪沉积物特征及厚度,河套沉积基底构造的探测进行了大量研究工作,并利用电法剖面对该区第四纪含水层分布规律进行了初步研究。通过重磁联合反演、天然地震数据,分析并推断了研究区由南向北的4条隐伏断层F₁-F₄及狼山-色尔腾山前大断裂F₅,同时揭露了该区结晶基底的起伏及埋深,研究区南部基底深度2.5~4.2 km,北部中心基底最大埋深可达6 km,北部色尔腾山前断裂带迅速升至0~1 km。      

莺歌海盆地前新生代基底特征

结合盆缘露头、盆地基底钻井及重磁震资料,综合研究莺歌海盆地前新生代基底特征。基于盆地西北缘Song Da带18个剖面点地层序列、166件岩石样品密度和2 800套磁化率测量结果,建立密度--磁化率交汇图版,约束盆内地震剖面和重磁异常解释,通过海陆结合的方法填制出盆地基底地质图。其前新生界由前震旦系、寒武系—上三叠统下部、上三叠统上部—白垩系三个构造层构成,它们沿红河断裂呈北西向分布,中间老,为前震旦纪中—高级变质岩;两侧新,向西为中生代沉积岩,向东为古生代浅变质岩、灰岩。     

哈尔滨-尚志MT阵列剖面研究

根据哈尔滨-尚志连续电磁剖面测深结果,研究了松辽盆地东缘盆山结合部的地质结构特征,尤其是对深层的地质结构取得了重要的认识.盆山结合部划分出3个基本单元:松辽盆地、滨东隆起区和张广才岭隆起区.盆地一侧的盖层具有双重结构.盆地具双重基底,即浅变质岩的褶皱基底与侵入岩的结晶基底.莫霍面在盆地一侧隆起,向张广才岭变深,隆起幅度4km.断裂主要为岩石圈与壳断裂,对构造单元起控制作用.     

福建武夷山仙店—浦城渔梁逆冲构造带控矿作用

武夷山仙店—浦城渔梁逆冲构造带发育于崇安火山盆地东缘,呈北东向展布,由盆缘逆断层为主体,局部具推覆特征。断裂下盘以中新生代中酸性火山岩系为主,上盘主要分布前震旦系变质岩系和南北向中酸性侵入岩,构造性质与地层岩性的差异导致其成矿作用不同,逆冲断裂与火山岩系控制铀成矿作用,推覆构造与变质岩系影响铅锌多金属成矿作用。     

Coupled basin evolution and late-stage metamorphic core complex exhumation in the southern Basin and Range Province, southeastern Arizona

Records of lithospheric extension and mountain-range uplift are most continuously contained within syntectonic sedimentary rocks in basins adjacent to large structural culminations. In southeastern Arizona, metamorphic core complexes form mountain ranges with the highest elevations in the region, and supposedly much less extended terranes lie at lower elevations. Adjacent to the Santa Catalina-Rincon metamorphic core complex, within the Tucson Basin, stratigraphic-sequence geometries evident in a large suite of 2-D seismic reflection data suggest a two-phase basin-evolution model controlled by the emplacement and subsequent uplift of the core complex. In its earliest stage, Phase I of basin formation was characterized by extensive faults forming relatively small-scale proto-basins, which coalesced with the larger basin-bounding detachment fault system. Synextensional sedimentation within the enlarging basin is evidenced by sediment-growth packages, derived from adjacent footwall material, fanning into brittle hanging-wall faults. During this phase, volcanism was widespread, and growth packages contain interbedded sediments and volcanic products but, paradoxically, no mylonitic clasts from the adjacent metamorphic core complex. Phase II of basin evolution begins after a significant tectonic hiatus and consists of a symmetric deepening of the central basin with the introduction of mylonitic clasts in the basin fill. This is coupled with the activation of a series of high-angle normal faults ringing the core complex. These observations suggest a two-phase model for metamorphic core complex evolution, with an initial stage of isostatic core complex emplacement during detachment faulting that resulted in little topographic expression. This was followed, after a significant tectonic hiatus, by late-stage exhumation and flexural uplift of the Santa Catalina-Rincon metamorphic core complex through younger high-angle faulting. Moreover, the geometry of upper basin fill units suggests an extremely low effective elastic thickness in the region and that flexural uplift of the core complex induced asymmetric transfer of ductile mid-crustal rocks from beneath the subsiding Tucson Basin to the uplifting mountain range.     

北黄海盆地构造几何学研究新进展

北黄海盆地是发育于胶辽隆起背景之上的中、新生代沉积盆地。研究表明,北黄海中、新生代沉积盆地的基底由古生界沉积岩层和前寒武纪变质岩系等组成,盆地不同程度地发育于中新生代下构造层(J₃-K₁)、中构造层(E₂-E₃)和上构造层(N).从油气资源和中、新生代地层发育情况出发,将北黄海海域划分为辽东-海洋岛隆起区、北黄海盆地和胶北-刘公岛隆起区3个一级构造单元。其中北黄海盆地包括6个二级构造单元和24个三级构造单元;盆地内褶皱、断裂构造十分发育,褶皱构造可划分为区域挤压型、局部伴生型和披覆型3类,断裂构造主要可见近EW-NE向、NW向和NNE向3组,其中近EW-NE向和NNE向断裂比较发育,控制着盆地隆、坳分布格局和沉积特征。      

Geochemistry of metamorphic rocks of the Kurai block (Gorny Altai)

We consider the primary nature and sources of the protoliths of metamorphic rocks of the Kurai block located in the large Teletskoe-Kurai system of deep faults separating the Gorny Altai and West Sayan structures. It has been established that the protoliths of the Kurai block metapelites were deposits of transitional crust: They lack typical rocks of mature continental crust (arkoses, litharenites) and have reduced (relative to the upper continental crust) contents of lithophile elements and elevated contents of transition elements. The average Nd model age of the protoliths of the metapelites of the Kurai complex corresponds to the Middle Riphean (1.4-1.6 Ga). The metabasites of the Kurai complex are similar in petrologic composition to metamorphic products of oceanic basalts. It is shown that the formation of metamorphic associations of the Kurai block was caused by tectonometamorphic transformations of a compositionally heterogeneous rock unit (basalts, aluminous and volcanomict sediments), which were, most likely, a fragment of Middle Cambrian-Early Ordovician turbidite basin with an oceanic basement.     

Alluvial deposits from the strike-slip fault Lo River Basin (Oligocene/Miocene), Red River Fault Zone, north-western Vietnam

The Lo River Basin (LRB) is one of several narrow sedimentary basins associated with the main faults of the Red River Fault Zone separating the South China and Indochina microplates. The basin is located on the NE boundary of the high-grade metamorphic Con Voi Massif and the sedimentary and metasedimentary Viet Bac fold zone in north-eastern Vietnam.The LRB is filled with over 6000 m of Oligocene/Miocene alluvial deposits. The source area was probably located on the NE margin of the basin and was composed mostly of low-grade metamorphic rocks with a minor component of sedimentary rocks. Three alluvial systems are recognised. The oldest system was a proximal braided river system, with the minor occurrence of alluvial fans. The younger systems record changes in clast composition and lithofacies, which suggests a transition from a distal braided river to a distal braidplain system. The LRB fill shows a range of features characteristic of strike-slip fault basins. The origin of the LRB is correlated with the left-lateral transtensional regime. The present shape of the basin is a result of post-sedimentation tectonic activity.     

燕山构造带凤山盆地早白垩世的沉积过程

凤山盆地是燕山构造带内的一个早白垩世伸展盆地。盆地内沉积岩相和相组合的详细分析结果显示,盆地内部发育不同的沉积相带,并显示明显的空间变化。盆地北部和西部边缘以冲积扇砾岩和扇三角洲砂岩、砾岩沉积为主,盆地中心为湖泊细粒沉积。古流向和物源恢复结果证明,盆地沉积物主体来自北部和西部变质岩基底。盆地构造沉降和沉积过程主要受北缘和西缘张性断层的控制。断层下盘基底岩石的抬升与盆地边界正断层活动相关,从而成为盆地主要的物源区。凤山盆地的演化可划分为3个阶段,即早期火山喷发阶段、中期强烈断陷阶段和晚期填平阶段。     

Kinematics of the Southern Rhodope Core Complex (North Greece)

The Southern Rhodope Core Complex is a wide metamorphic dome exhumed in the northern Aegean as a result of large-scale extension from mid-Eocene to mid-Miocene times. Its roughly triangular shape is bordered on the SW by the Jurassic and Cretaceous metamorphic units of the Serbo-Macedonian in the Chalkidiki peninsula and on the N by the eclogite bearing gneisses of the Sideroneron massif. The main foliation of metamorphic rocks is flat lying up to 100 km core complex width. Most rocks display a stretching lineation trending NE–SW. The Kerdylion detachment zone located at the SW controlled the exhumation of the core complex from middle Eocene to mid-Oligocene. From late Oligocene to mid-Miocene exhumation is located inside the dome and is accompanied by the emplacement of the synkinematic plutons of Vrondou and Symvolon. Since late Miocene times, extensional basin sediments are deposited on top of the exhumed metamorphic and plutonic rocks and controlled by steep normal faults and flat-ramp-type structures. Evidence from Thassos Island is used to illustrate the sequence of deformation from stacking by thrusting of the metamorphic pile to ductile extension and finally to development of extensional Plio-Pleistocene sedimentary basin. Paleomagnetic data indicate that the core complex exhumation is controlled by a 30° dextral rotation of the Chalkidiki block. Extensional displacements are restored using a pole of rotation deduced from the curvature of stretching lineation trends at core complex scale. It is argued that the Rhodope Core Complex has recorded at least 120 km of extension in the North Aegean, since the last 40 My.