东天山红石金矿区石英钠长斑岩Ar-Ar和U-Pb年龄及构造和成矿意义讨论

红石金矿区位于东天山觉罗塔格地区秋格明塔什—黄山韧性剪切带内, 石英钠长斑岩为矿体顶底板围岩, 该金矿的赋矿地层干墩组为一套以类复理石杂砂岩建造为主的岩石组合。石英钠长斑岩和地层均发生较强的糜棱岩化, 石英钠长斑岩的锆石SHRIMP U-Pb定年结果为(344±4) Ma, 说明被该岩体侵入的干墩组地层时代不晚于(344±4) Ma, 从同位素年代学角度上限定了干墩组地层时代为早石炭世, 表明秋格明塔什—黄山地区在该时期还处于深海-半深海沉积环境。对石英钠长斑岩糜棱岩化阶段形成的绢云母进行40Ar-39Ar阶段升温测年分析, 得到坪年龄为(262±1) Ma。该年龄与秋格明塔什—黄山韧性剪切带中-西段右行走滑剪切变形作用时代一致, 说明红石金矿可能与走滑剪切作用有关, 结合前人对红石金矿成矿时代的研究结果, 认为秋格明塔什—黄山韧性剪切带右行走滑剪切作用是红石金矿成矿作用的主因。     

白云鄂博矿区北部韧性剪切带特征及其构造意义

在白云鄂博主矿北西约6.5km处的查干楚鲁一带,有一条近东西向延伸的断层带,前人在该带中部识别出了蛇绿岩混杂堆积。本文作者在蛇绿岩东部的大理岩质糜棱岩中发现鞘褶皱、拉伸线理及旋转碎斑系等变形构造,在大理岩周围发现石英岩型宏观压力影构造,在变质石英砂岩中识别出褶劈理以及方解石脉等相关构造,在这条东西向断裂带北边发现典型的黄铁矿型压力影。根据上述特征判断,查干楚鲁一带为一条近东西向延伸的韧性剪切带,同时具有NEE—SWW向逆左旋走滑的特征。该带揭示出蒙古洋板块与华北板块在晚古生代汇聚拼合的基本格局。     

Dynamics of the formation of the Cenozoic Uglovsky basin (Southern Primorye)

The Uglovsky basin located in the southern part of Primorye is filled in with Eocene terrigenous predominantly nonmarine coal-bearing deposits. The basin is considered to be the result of syn-strike-slip extension, which occurred prior to the opening of the Sea of Japan and was related to dextral displacements along NNE-trending faults.     

A note on 2-D lithospheric deformation due to a blind strike-slip fault

Analytical solution for the problem of a surface-breaking long strike-slip fault in an elastic layer overlying an elastic half-space is well known. The purpose of this note is to obtain the corresponding solution for a blind fault. Since the solution is valid for arbitrary values of the fault-depth and the dip angle, the effects of these two important fault parameters can be studied numerically. The variation of the parallel displacement and shear stress with the distance from the fault is studied numerically for different values of the fault-depth and dip angle.     

Late Quaternary sinistral slip rate along the Altyn Tagh fault and its structural transformation model

The Altyn Tagh Fault (ATF) is a major boundaryfault on the northern margin of the Qinghai-TibetanPlateau and is also the longest sinistral strike-slip faultat a lithospheric scale in the Eurasian Plate. Its exis-tence has directly affected regional features of neotec-tonics, topography, geomorphology, Quaternary geol-ogy, recent crustal deformation, seismicity, climatechange and ecological environment for fauna and florain China[1—6]. The sinistral slip on the ATF and activethrusting-fo…     

Did the Altyn Tagh fault extend beyond the Tibetan Plateau?

The pre-Miocene northeastern termination of Altyn Tagh fault is a critical outstanding problem for understanding the mechanics of Cenozoic deformation resultant from the Indo-Asian collision and mechanisms of Tibetan Plateau formation. Structures beyond the widely accepted NE end of the Altyn Tagh fault, near the town of Yumen, are needed in order to accommodate strike-slip deformation related to plate-like lateral extrusion tectonics, but structures with the necessary slip magnitudes and histories have not been identified. We report on a series of newly recognized and documented E to ENE-striking faults within the Alxa block, NE of the Tibetan Plateau, that are visible on remotely sensed images and confirmed by field studies. These structures are demonstrably left-lateral faults based on offset geology and kinematic indicators such as striae and s-c fabrics in fault gouge. The faults have post-Cretaceous offsets of at least tens to possibly > 150 km, but limited post-Miocene displacement, constrained by offset sedimentary basins. These characteristics suggest that strike-slip faults of the Alxa region have a similar structural history as the central-eastern Altyn Tagh fault and can provide a mechanism for accommodating Oligocene-Early Miocene extrusion along the Altyn Tagh fault.     

青藏东北缘早第三纪盆地充填的沉积型式及构造背景--以囊谦和下拉秀盆地为例

一系列中小型早第三纪红色盆地出露于青藏高原的东北缘,它们是在印度-欧亚板块碰撞过程中因陆壳变形和高原隆升产生的。典型早第三纪盆地的地质填图和详细的沉积学研究,及构造、沉积和岩浆热事件的综合分析表明,这些盆地具有两阶段构造-沉积特征,即早期受控于逆冲挤压背景,盆地接受底部冲积扇体系的粗碎屑岩段沉积,局部伴有岩浆活动;晚期受控于走滑-拉分背景,盆地充填湖泊-三角洲体系的含膏砂泥岩段夹薄层灰岩,并伴有广泛的岩浆作用。青藏东北缘早第三纪盆地在盆地构造格架、沉积层序结构、沉积物组成和岩浆活动等方面均存在明显的阶段性演化。盆地古水流统计和岩浆岩4 0 Ar/ 3 9Ar定年结果表明,青藏东北缘早第三纪盆地沉积物主要形成于始新世晚期-渐新世早期 (38～ 2 9Ma)。盆地沉积型式和岩浆活动受印度-欧亚板块碰撞早期逆冲挤压和走滑-拉分构造格局的控制。     

斜向走滑构造分形和变形分解——以滇西北金沙江结合带为例

从分形和变形分解的角度讨论了滇西北金沙江结合带斜向走滑构造分形和变形分解的某些特征。     

The Altun Fault: Its Geometry, Nature and Mode of Growth

The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours including thrusting, sinistral strike slip and normal slip. The strike slip and normal slip mainly occurred in the Cretaceous-Cenozoic and Plio-Quaternary respectively, whereas the thrusting was a deformation event that has played a dominant role since the late Palaeozoic (for a duration of about 305 Ma). The formation of the Altun fault was related to strong inhomogeneous deformation of the massifs on its two sides (in the hinterland of the Altun Mountains contractional deformation predominated and in the Qilian massif thrust propagation was dominant). The fault experienced a dynamic process of successive break-up and connection of its segments and gradual propagation, which was synchronous with the development of an overstep thrust sequence in the Qilian massif and the uplift of the Qinghai-T     

Paleoseismology of the Itoigawa-Shizuoka tectonic line in central Japan

The 150-km-long Itoigawa-Shizuoka tectonic line active fault system (ISTL)in central Japan is one of the most active Quaternary fault systems inJapan. Estimated slip-rates on the fault system are as large as 10 m/ka, butthe historic seismicity has been low since 841 A.D. with no largeearthquakes recorded. The high slip rates contrast with the long time sincethe last major earthquake on the ITSL and indicates the high potential of a largeearthquake from the ISTL. Based on slip-rate estimates, more than 10 mof potential slip may have accumulated on the fault system since the 841A.D. earthquake. Recent paleoseismolgical studies on the middle andnorthern parts of the ISTL have determined that the average recurrenceinterval of surface-faulting earthquakes on the middle ISTL is 680 to 825years (Gofukuji fault) and 1258 to 1510 years in the northern ISTL. These data suggest the most recent event on both northern and middleISTL occurred in 841 A.D. The results highlight the high seismic potentialof the ISTL. Additional studies of the entire ISTL are needed to define theextent of the next rupture.