长白山天池火山主断裂活动与热液蚀变带

在野外考察中发现，天池破火山口内壁同一层位不同段的近水平向红褐色、砖红色热液蚀变带顶界面有明显高差热液蚀变顶界面，北段(靠近天文峰)比南段(朝鲜境内靠近将军峰)高出约110m。热液蚀变带顶界面可作为判断构造运动的标志面。北段与南段顶界面的高差，反映了自热液蚀变以来，天池火山北东向主断裂六道沟-天池-甑峰山断裂北西盘的抬升幅度大于南东盘，这可能是天池北西部较南东部地形坡度更陡、水系更发育的内在原因。北西向主断裂——白山镇-天池-金策断裂北东盘的抬升幅度大于南西盘。由热液蚀变和古风化壳特征观察到的北东向主断裂的近期垂向活动速率大于北西向主断裂的活动速率。这两条在天池交叉的主断裂将天池火山切割成4个块体，它们的抬升幅度从大到小依次为北、西、东、南块体。北块体抬升幅度最大，这与深地震测深、大地电磁探测等得出的天池北部岩浆囊较浅的结果有较好的对应关系和一定的成因联系。     

Fabric development during shear deformation in the Main Central Thrust Zone, NW-Himalaya, India

Quartz microfabrics and associated microstructures have been studied on a crustal shear zone—the Main Central Thrust (MCT) of the Himalaya. Sampling has been done along six traverses across the MCT zone in the Kumaun and Garhwal sectors of the Indian Himalaya. The MCT is a moderately north-dipping shear zone formed as a result of the southward emplacement of a part of the deeply rooted crust (that now constitutes the Central Crystalline Zone of the Higher Himalaya) over the less metamorphosed sedimentary belt of the Lesser Himalaya. On the basis of quartz c- and a-axis fabric patterns, supported by the relevant microstructures within the MCT zone, two major kinematic domains have been distinguished. A noncoaxial deformation domain is indicated by the intensely deformed rocks in the vicinity of the MCT plane. This domain includes ductilely deformed and fine-grained mylonitic rocks which contain a strong stretching lineation and are composed of low-grade mineral assemblages (muscovite, chlorite and quartz). These rocks are characterized by highly asymmetric structures/microstructures and quartz c- and a-axis fabrics that indicate a top-to-the-south sense that is compatible with south-directed thrusting for the MCT zone. An apparently coaxial deformation domain, on the other hand, is indicated by the rocks occurring in a rather narrow belt fringing, and structurally above, the noncoaxial deformation domain. The rocks are highly feldspathic and coarse-grained gneisses and do not possess any common lineation trend and the effects of simple shear deformation are weak. The quartz c-axis fabrics are symmetrical with respect to foliation and lineation. Moreover, these rocks contain conjugate and mutually interfering shear bands, feldspar/quartz porphyroclasts with long axes parallel to the macrosopic foliation and the related structures/microstructures, suggesting deformation under an approximate coaxial strain path.On moving towards the MCT, the quartz c- and a-axis fabrics become progressively stronger. The c-axis fabric gradually changes from random to orthorhombic and then to monoclinic. In addition, the coaxial strain path gradually changes to the noncoaxial strain path. All this progressive evolution of quartz fabrics suggests more activation of the basal, rhomb and a slip systems at all structural levels across the MCT.     

第一勘探类型铀矿床的主要指标及合理勘探网度的探讨

本文通过苏崩矿床不同勘探网度的主矿体厚度、品位及其变化系数和储量等主要参数对比研究，提出第一勘探类型铀矿床应具的规模、稳定性、连续性指标及各级储量的勘探工程间距。     

大同－阳高两次地震的对比分析

１９８９年１０月，１９９１年３月，在山西北部大同盆地先后发生Ｍｓ６．１、Ｍｓ５．８两次中强地震。对比这两次地震的序列、空间分布及能量释放等存在很大差异。两次地震属同一地震序列，５．８级地震的活动规律具有晚期强余震的特点，是６．１级地震活动的一次大的起伏。进一步分析表明，大同—阳高的两次地震活动，以及在此期间山西地区发生的一系列５级左右地震活动，是华北地区区域应力场增强，较大范围内应力增加和传递的结果。     

华北M≥6级地震跟踪预测的初步研究

本文认为华北地震是印度板块碰撞和太平洋板块俯冲联合作用下形成的。以我国东部大陆应力场近似幅射中心Q(λ_o=100°E、ψ_o=35°N)做印度板块碰撞影响下青海块体对华北俯冲作用代表、以东北M≥6深震近似重心S(λ_o=131.5°E、ψ_0=42.5°N、h=-575千米)做太平洋板块对华北俯冲作用代表,本世纪米华北M≥6地震呈现距此简化力源由近及远成串有序地发生,各活动期起始分别与青藏地震活动高潮和东北深震活动高潮相关的图象。据此建立了华北M≥6地震预测模型Q和模型S,历史地震预测实验表明两模型可以为华北M≥6地震预测提供线索。本文还对华北地震活动图象做了初步解释和讨论。     

固体围压下完整花岗岩粘滑现象的实验研究

本文用完整的花岗岩样品在固体围压三轴实验装置上压缩,研究围压和应变速率对岩样变形破裂过程、粘滑应力降、粘滑复发间隔及样品主破裂几何分布的影响。结果表明,加载速率较低时,粘滑应力降较大,复发间隔较长且分布无规律。加载速率越大,粘滑应力降越小,复发间隔也近似相等,粘滑事件表现出准周期性。围压和应变率较低时,岩石的主破裂会演变成两个交叉的共轭断裂面;而围压和应变率较高时,岩石的主破裂则演变成单一断裂面或入字形断裂面。本文结果对认识中国大陆板内地震孕育、发生及重复过程;研究地震重复发生的机制及影响地震复发间隔的主要因素都有重要意义。     

Kinematic variations across Eastern Cordillera at 24°S (Central Andes): Tectonic and magmatic implications

The Eastern Cordillera (Central Andes,  24°S) consists of a basement-involved thrust system, resulting from Miocene–Quaternary eastward migrating compression, separating the Puna plateau from the Santa Barbara System foreland. The inferred Tertiary strains arising from shortening in the Eastern Cordillera and Santa Barbara System are similar, higher than in the Puna. Slip data collected on the major  N–S trending faults of Eastern Cordillera show a westward progression from dip-slip (contraction) to dextral and sinistral motions. This, consistently with established tectonic models, may result from partitioning due to the oblique Mio-Quaternary underthrusting of the Brazilian Shield north of 24°S. This strain partitioning has three main implications. (1) As the dextral and sinistral shear in the Eastern Cordillera are  62% and 29% of the compressive strain respectively, the Eastern Cordillera results more strained than Santa Barbara System foreland, contrary to previous estimates. (2) The partitioning in the Eastern Cordillera may find its counterpart in that to the west of the Central Andes, giving a possible structural symmetry to the Central Andes. (3) The easternmost N–S strike-slip structures in the Eastern Cordillera coincide with the easternmost Mio-Pliocene magmatic centres in the Central Andes, at  24°S. Provided that, further to the east, the crust is partially molten, the absence of magmatic centres may be explained by the presence of pure compressive structures in this portion of the Eastern Cordillera.     

Salt tectonics and tear faulting in the central part of the Zagros Fold-Thrust Belt,Iran

The central part of the Zagros Fold-Thrust Belt is characterized by a series of right-lateral and left-lateral transverse tear fault systems, some of them being ornamented by salt diapirs of the Late Precambrian–Early Cambrian Hormuz evaporitic series. Many deep-seated extensional faults, mainly along N–S and few along NW–SE and NE–SW, were formed or reactivated during the Late Precambrian–Early Cambrian and generated horsts and grabens. The extensional faults controlled deposition, distribution and thickness of the Hormuz series. Salt walls and diapirs initiated by the Early Paleozoic especially along the extensional faults. Long-term halokinesis gave rise to thin sedimentary cover above the salt diapirs and aggregated considerable volume of salt into the salt stocks. They created weak zones in the sedimentary cover, located approximately above the former and inactive deep-seated extensional faults. The N–S to NNE–SSW direction of tectonic shortening during the Neogene Zagros folding was sub-parallel with the strikes of the salt walls and rows of diapirs. Variations in thickness of the Hormuz series prepared differences in the basal friction on both sides of the Precambrian–Cambrian extensional faults, which facilitated the Zagros deformation front to advance faster wherever the salt layer was thicker. Consequently, a series of tear fault systems developed along the rows of salt diapirs approximately above the Precambrian–Cambrian extensional faults. Therefore, the present surface expressions of the tear fault systems developed within the sedimentary cover during the Zagros orogeny. Although the direction of the Zagros shortening could also potentially reactivate the basement faults as strike-slip structures, subsurface data and majority of the moderate-large earthquakes do not support basement involvement. This suggests that the tear fault systems are detached on top of the Hormuz series from the deep-seated Precambrian–Cambrian extensional faults in the basement.     

位移观测值协方差矩阵模拟及其在整体解算地壳应变场中的应用

借助高斯型函数模拟分散分布的不同监测网点位移观测值的协方差矩阵,并将其应用于广东新丰江地区地壳应变场的计算中．结果表明：本文的方法不仅计算简便,模拟效果及计算稳定性较好,而且对联系分散分布的单元有一定的意义