桃山铀矿田桃山断裂及其保矿作用

桃山铀矿田位于江西省中部,断裂构造发育,既有成矿构造,也有保矿构造,其中斜贯桃山矿田的桃山断裂即是一保矿构造,它形成于车免近时期,走向北东,倾向南东,右行正断,并具铰链断层性质,上盘地块掀斜下落,致使上盘成矿壳层向NW和NE倾斜,由于倾末端的侵蚀深度较小,保矿条件较好,加强这些地带的铀矿勘查和评价具有重要意义。     

Penecontemporary tectonic forms in basement areas: evidence derived from quarry exposures on northwestern Eyre Peninsula,South Australia

Monitoring of quarry exposures on northwestern Eyre Peninsula, South Australia has shown that the granite domes of that region are structurally complex features, commonly with several structural domes within each topographic form. The rock masses are in horizontal compression so that few steeply inclined fractures have been penetrated by water and hence are not weathered, though sheet fractures, which are tectonic features, are arched, dilated, and thus readily infiltrated by water. Neotectonic forms, such as fault scarps, A-tents, or pop-ups, and disturbed blocks are still developing. These observations provide further evidence of neotectonism, even in cratonic lands.     

昆仑山口羌塘组磁性地层与新构造运动

格尔木昆仑山口羌塘组厚596m,磁性地层年代为2.90-0.65MaBP,不整合在羌塘组上的望昆冰碛层年龄约为0.65-0.6MaBP,其下惊仙冰期年龄约为3.0MaBP。羌塘组中新发现的三趾马化石年龄为2.08MaBP,三趾马生存高度为海拔1000-2000m,古纬度为32.56°,计算出东昆仑地区第四纪以来上升速率为2.3-3.1mm/a,向北水平移动速率143mm/a,西大滩左行走滑断层滑动速率为10mm/a。      

赣中宁都北部地区新构造活动初探

江西省中部宁都北部地区断裂构造发育,ETM453合成图像线形影像主要有北东向、北北东向和北西向,少量近东西向,线性构造具明显的新构造运动踪迹,地质证据有断层的走滑、地震、温泉和水系被错断等。其中,斜贯研究区中部的桃山断裂构造为一向南东下滑的右行张扭性断层,具捩断层性质,其挽近时期明显的构造运动造成桃山构造上盘距构造面不远的地带,特别是桃山构造的北东端如打鼓寨岩体北东部及外围,侵蚀作用较弱,保矿条件较好,具有较大的找矿潜力。     

青海湖的地质构造前景及形成演化

青海湖地区位于３个构造单元及多条深断裂的交汇部位,结构复杂,强度较弱。上新世出现断陷,中更新世成湖。湖盆可划分为３个地垒和３个次级断陷盆地。其形成和演化受中祁连南缘大断裂带、宗务隆山－青海南山大断裂带和黑马河－达晶大带重新活动及其它ＮＷＷ,ＮＷ,ＮＮＷ,ＳＮ,ＮＥ抽断裂的活动及伴随的差异隆升所控制,与青藏高原的隆升演化有密切关系,尤其是可能与青藏高原发生后造山伸展作用有关的应力场转变造成的负反转构     

三峡地区新构造活动与滑坡分布关系

三峡库区广泛发育有“层状”地貌，是地壳大面积隆升的产物。现今构造应力场的方向总体表现为NNE—NE向，主压应力场并不水平，其仰角约为30°。新构造应力场控制地壳不均衡隆升结果造成坡体演化阶段不同，并控制滑坡的时空分布，奉节以东地区坡体处于变形破坏初期阶段，滑坡与崩塌共存，坡体陡高，滑带倾角大，重力背斜变形构造多见；奉节以西地区坡体处于变形破坏的中后期阶段，以滑坡发育为主要特征，坡体平缓，滑带倾角平缓，重力背斜变形构造少见；新构造应力场控制水平运动对滑坡的滑动方向、滑坡的破坏强度主要体现为构造应力场与自重应力场的叠加机制。     

遥感技术在南昌地区新构造运动研究中的应用

在第四纪河湖相冲(堆)积物十分发育且分布很广的南昌地区,利用TM5、TM4、TM3彩色合成图像清晰地辨别出二种新构造运动: 垂直升降运动和水平移动。垂直升降运动造成了赣江、抚河由西向东迁移; 水平移动引起青岚湖、军山湖等湖泊拉张裂开。指出了这二种新构造运动所引发的河(湖)岸崩岸等地质灾害。     

青海湖的地质构造背景及形成演化

青海湖地区位于 3个构造单元及多条深断裂的交汇部位 ,结构复杂 ,强度较弱。上新世出现断陷 ,中更新世成湖。湖盆可划分为 3个地垒和 3个次级断陷盆地。其形成和演化受中祁连南缘大断裂带、宗务隆山 -青海南山大断裂带和黑马河 -达日大断裂带重新活动及其它NWW ,NW ,NNW ,SN ,NE向断裂的活动及伴随的差异隆升所控制 ,与青藏高原的隆升演化有密切关系 ,尤其是可能与青藏高原发生后造山伸展作用有关的应力场转变造成的负反转构造有重要关系。中中新世夷平面形成以来的新构造活动和青海湖的形成演化具明显的脉动性。中中新世以来的新构造活动可分为 5个阶段 ,青海湖形成演化过程可大致分为 9期     

贝加尔湖滨奥里洪地区新构造特征及其成因模式初探

贝加尔裂谷带是全球典型的大陆裂谷带之一,新构造运动强烈。滨奥里洪地区是贝加尔裂谷带断裂发育最完好的地区。位于滨奥里洪中部的萨尔玛河谷和奥里洪门新构造运动非常强烈,萨尔玛河谷在地形上呈规则的折线状,而奥里洪门发育有两侧对称的湖湾。沿萨尔玛河谷发育有一组X型节理,而奥里洪门两侧发育有完好的断层三角面山,因此,萨尔玛河谷和奥里洪门可能是在早期追踪张裂的基础上发育起来的。滨奥里洪地区还发育有一系列NE和NW走向的次级断裂,它们的发育受滨海断裂铲式枢纽断层特征的控制。分析这些次级断裂的特征和性质,提出了与它们发育有关的三种作用力:①枢纽断层造成的NE-SW向局部拉张;②铲式断层的旋转效应产生反向滑动;③铲式断层的不均匀旋转产生剪切效应,并在此基础上对滨奥里洪地区的新构造运动过程作了概括和总结。     

Modern sedimentation in the Lower Negro River, Amazonas State, Brazil

The Negro River, which flows through the north central Amazon Basin, is one of the largest tributaries of the Amazon. The name “Negro” comes from the colour of its water, which reflects the large quantity of dissolved humic acids and iron oxides that also gives the water its characteristic acid pH. The river is estimated to have the fifth largest water discharge in the world, about 30,000 m³/s. The Negro River is characterized by a high dissolved load but a low energy system. Neotectonics and water quality are the principal factors that control the modern sedimentation in the Lower Negro River. The Lower Negro River is controlled largely by a NW–SE tectonic lineament, that is a segment of a major tectonic transcurrent dextral megasystem of the Amazon Basin. Neotectonism in this area is responsible for the depth of the river and for the occurrence of steep “falésias” (cliffs), along some parts of its borders. It also seems that neotectonics have influenced the origin of the Anavilhanas Islands, which are a series of anastomosed, elongated silty clayey channel bars, with internal round or long narrow lakes. The “igapó”, which is the forested area flooded during part of the year, appears to have a neotectonic origin as well. Igapós are located on intermediate blocks between the high blocks of the “terra firme” and the low blocks of the channel. The absence of clastic sediments carried in suspension is related to the rare appearance of floodplains, which are limited to very thin layers of fine sediments, located on the abrasion shelfs carved in clastic deposits of the Alter do Chão Formation. Sand bars occur in places along the base of the cliffs and along the edges of the channel system. These sand bars are composed of quartz sand, derived from the reworking of the sand of the Alter do Chão Formation.