台阶式逆冲推覆－安徽沿江煤田的基本构造型式

运用现代构造几何最新理论，指出安徽沿江煤田的基本构造型式为台阶式逆冲推覆构造，并对其构造类型进行详细的分类。     

云南金顶超大型铅锌矿床的成矿地质背景

采用构造－沉积综合分析的方法，研究了金顶超大型铅锌矿床成矿的盆地、构造和深部地质背景。研究表明，控矿的古新世－中始新世盆地为走滑拉张盆地，研究区先后经历了古新世－中始新世早期的走滑和拉伸，中始新世－渐新世的挤压推覆和中新世的隆升和走滑，分析了盆地演化、沉积体系、同生断裂活动和逆冲推覆等对金顶超大型铅锌矿床的控制作用，探讨了可能的成矿过程。     

秦岭略阳—白水江地区双向推覆构造及形成机制

秦岭勉县—略阳板块缝合带在略阳地区构造样式总体表现为以一系列韧性逆冲断层为骨架,不同岩片(块)由北向南逆冲叠置的叠瓦状构造系,并在北部以状元碑走滑剪切转换带为界与白水江—光头山自南向北的逆冲推覆构造系构成不对称双向推覆构造。两大推覆构造系结构构造分别具有明显的分带性。略阳逆冲构造系包括:前缘褶皱—逆冲带、中部逆冲叠瓦带和后缘逆冲带;白水江—光头山逆冲推覆构造系由前锋推覆带、中部褶皱—逆冲带和根带组成,并显示前展式扩展方式。双向推覆构造形成于印支晚期—燕山早期,是扬子板块北缘碧口地块与南秦岭地块强烈碰撞造山的产物,反映了板块边界对造山带构造变形样式的控制作用以及造山带结构构造的复杂性。     

漠滨脆—韧性剪切带型金矿床控矿构造研究

层间右旋逆冲脆—韧性剪切带构造控制漠滨金矿床。剪切带变形过程经历了早、中、晚3个阶段。而金矿化的形成和富集又与剪切带多阶段的演化密切相关,金矿化是剪切构造作用形成的。因此,剪切带既是控矿因素,又是重要的成矿机制,属层间逆冲脆—韧性剪切带型金矿床。     

MULTISTAGE SUPERIMPOSED DEFORMATION AND THEEVOLUTION OF THE NORTHEASTERN MARGIN OF YANGTZE BLOCK

Multistage superimposed deformation has been discussed systematically based on the progress of the stratigraphic sequences of the northeastern margin of Yangtze Block. The new-discovered first stage deformation of those sequences occurred from the middle Triassic to the end of early Jurassic together with development of regional folding, which was resulted from the deep detachment shearing tending toward NW-WNW. The folds dip to east and fall down toward west, and were superimposed by the main stage folding. Thereafter, a series of folds were developed with axes trending toward northeast. Consequently normal folds occurred on the normal limbs while overturned fold on the overturned limbs during the first stage folding. The detachment or thrust was form edfrom late Jurassic to early Cretaceous. Due to the uplifting of Dabie and the Wannan Mountains in the north and south sides, the bi-directional thrusting belt was formed by gravity flowing from the Mountains toward the center of the basin along the north side of Xuancheng and south side of Guichi. The deformation geodynamics was discussed simply based on the newly recognized information about the tectonic evolution.     

Une carte gravimétrique haute résolution du massif du Mont-Blanc : implications structuralesA high-resolution gravity map of the Mont-Blanc massif: structural consequences

We performed a gravity survey in the Mont-Blanc and Aiguilles Rouges ranges in order to improve the gravity data coverage of the Alpine crystalline external ranges, and to constrain the deep geometry of a crustal scale thrust. Preliminary results allow us to propose a geometry for the deep structure of the ranges, taking into account a major reverse fault that bounds the Mont-Blanc range: the Mont-Blanc shear zone. To cite this article: F. Masson et al., C. R. Geoscience 334 (2002) 1011–1019.     

Low-Pressure Metamorphism of Granulite Facies in an Early Proterozoic Orogenic Event in Central Inner Mongolia

According to the kinds of feldspar and rock associations in the Ai-rich gneisses, the low-pressure metamorphic crust of the Early Proterozoic granulite facies in central Inner Mongolia can be divided into southern and northern belts which are composed of six rock associations. They represent the relevant rock sequences of the layered metamorphic rock series formed under specific metamorphic temperature and pressure conditions as well as tectonic environments. Mineral inclusions and reaction texture have recorded that the medium-temperature high-pressure mineral assemblages are replaced by the high-temperature low-pressure mineral assemblages, thus, giving rise to: garnet+quartz→ hypersthene+plagioclase; kyanite→sillimanite and garnet+kyanite/sillimanite+quartz→cordierite. The deformation fabrics of the rocks, the change of mineral assemblages and the PTt path of metamorphism indicate that the contempranceous high-temperature normal-slip ductile shearing is the main cause of the formation of the low-pressure metamorphic crust of granulite facies. In the orogenic event, the co-action of thrusting and extension resulted in the change of a medium-temperature high-pressure metamorphic environment into the high-temperature low-pressure metamorphic conditions.     

Low-Pressure Metamorphism of Granulite Facies in an Early Proterozoic Orogenic Event in Central Inner Mongolia1

Abstract According to the kinds of feldspar and rock associations in the Al-rich gneisses, the low-pressure metamorphic crust of the Early Proterozoic granulite facies in central Inner Mongolia can be divided into southern and northern belts which are composed of six rock associations. They represent the relevant rock sequences of the layered metamorphic rock series formed under specific metamorphic temperature and pressure conditions as well as tectonic environments. Mineral inclusions and reaction texture have recorded that the medium-temperature high-pressure mineral assemblages are replaced by the high-temperature low-pressure mineral assemblages, thus, giving rise to: garnet+quartz? hypersthene+plagioclase; kyanite? sillimanite and garnet+ kyanite / sillimanite+quartz? cordierite. The deformation fabrics of the rocks, the change of mineral assemblages and the PTt path of metamorphism indicate that the contempranceous high-temperature normal-slip ductile shearing is the main cause of the formation of the low-pressure metamorphic crust of granulite facies. In the orogenic event, the co-action of thrusting and extension resulted in the change of a medium-temperature high-pressure metamorphic environment into the high-temperature low-pressure metamorphic conditions.     

白龙江地区的逆冲推覆构造

白龙江地区是由亚尔玛－舟曲后缘逆冲带、西倾山－武坪南逆冲岩席－飞来峰构造带、波海－白依－迭部－武都、略阳逆冲带、玛曲－南坪前缘挤压逆冲带及尕海－郎木寺沉降盆地等基本构造单元组合成的一个复杂的逆冲推覆构造体系，逆冲构造由北向南前展式扩展，逆冲作用主要导源于海西－印支期以来特提斯洋壳及若尔盖地块向中朝地块的后退式俯冲机制以及喜山期以来青藏高原被印度板块向北东方向的推挤作用，各逆冲构造单元对区域不同成因的金矿床（点）、带的控制作用，是研究区域矿产及成矿预测的重要地质依据。     

汶川M_S8.0地震地表破裂带北川以北段的基本特征

对北川-青川间汶川MS8.0地震地表破裂的野外地质调查表明,在这一段内主要存在一条地震地表破裂带,总体沿北川-青川断裂带分布。沿黄家坝、陈家坝、桂溪、平通、南坝、石坎等地的观察显示,该段地表破裂沿走向连续分布,结构单一,破裂长度为60~90km,地表破裂没有到达青川县关庄镇。可观察到的破裂长度在北川北至石坎之间,长62km,走向总体为20°~55°,运动学性质主要为右旋走滑逆冲。地震形成的地表破裂主要表现为垂向上的地表拱曲,指示了深部断层的逆冲性质;在水平运动方向上则主要表现为右旋走滑,不存在左旋走滑分量。地震地表破裂显示的同震垂直位移从西南段黄家坝的3m左右,向东北逐渐降低至南坝、石坎的1.5m左右;右旋水平位移没有明显变化或者略有增加,一般在1.5~2.0m之间。地表破裂特征表明,引起本次汶川MS8.0地震的发震构造是映秀-北川-青川断裂带,该断裂以逆冲运动为主,兼具右旋走滑分量,逆冲方向由NW向SE