Collision leading to multiple-stage large-scale extrusion in the Qinling orogen: Insights from the Mianlue suture

The geologic framework of the Phanerozoic Qinling–Dabie orogen was built up through two major suturing events of three blocks. From north to south these include the North China craton (including the north Qinling block), the Qinling–Dabie microblock, and the South China craton (including the Bikou block), separated by the Shangdan and Mianlue sutures. The Mianlue suture zone contains evidence for Mesozoic extrusion tectonics in the form of major strike–slip border faults surrounding basement blocks, a Late Paleozoic ophiolite and a ca. 240–200 Ma thrust belt that reformed by 200–150 Ma thrusts during A-type (intracontinental) subduction. The regional map pattern shows that the blocks are surrounded by complexly deformed Devonian to Early Triassic metasandstones and metapelites, forming a regional-scale block-in-matrix mélange fabric. Five distinct tectonic units have been recognized in the belt: (1) basement blocks including two types of Precambrian basement, crystalline and transitional; (2) continental margin slices including Early Paleozoic strata, and Late Paleozoic fluviodeltaic sedimentary rocks, proximal and distal fan clastics, reflecting the development of a north-facing rift margin on the edge of the South China plate; (3) out of sequence oceanic crustal slices including strongly deformed postrift, deep-water sedimentary rocks, sheeted dikes, basalts, and mafic–ultramafic cumulates of a Late Paleozoic ophiolite suite, developing independent of the rift margin in a separate basin; (4) out-of-sequence island-arc slices; (5) accretionary wedge slices. All the tectonic units were deformed during three geometrically distinct deformation episodes (D₁, D₂ and D₃ during 240–200 Ma). Units 2–4 involved southward thrusting and vertical then southward extrusion of about 20 km of horizontal displacement above the autochthonous basement during the D₁ episode. Thrust slices 20 km south of the Mianlue suture are related to this vertical extrusion due to the same rock assemblages, ages and kinematics. The D₂ and D₃ episodes folded all the units in a thick-skinned style about east–west (D₂) and west–northwest (D₃) axes in the Mianlue suture zone. An early foreland propagating sequence of accretion of Late Paleozoic rocks deposited above the Yangtze craton is not involved in D₁ deformation but is temporally equivalent to the D₂ and D₃ deformation in the Mianlue suture. Two stages of strike–slip faulting mainly occurred at the end of D₂ and D₃, respectively. During D₂ deformation, the Bikou block was obliquely indented to the ESE into the Mianlue suture, rather than being thrust over the Mianlue suture from the north as a part of the Qinling–Dabie microblock. During D₃ deformation, however, the Bikou block was bounded by the south boundary fault of the Mianlue suture, and the Yangpingguan fault on the south. These faults are coeval strike–slip faults, but of opposite senses, and accommodated minor southwestward extrusion of the Bikou block into Songpan–Ganze orogen. The other basement blocks north of the Mianlue suture were extruded eastward by about 20 km of lateral displacement, based on the offset of the Wudang dome, during the D₃ episode due to the northeastward indentation of the Hannan complex of the South China craton. Post-D₃ emplacement of granite, cutting across the strike–slip faults such as the Mianlue suture, provides a minimum age of 200 Ma for D₃ deformation. Therefore, based on insights from the evolution of the Mianlue suture, the D₂ and D₃ episodes in the Mianlue suture and its neighbors are not responsible for and associated with the two-stage extrusion of the Dabie UHP-HP terranes from the Foping dome to the present erosional surface (more than 350 km).     

DGSC—203型液动射流冲击器在地热井的试验

介绍了新研制的DGSC－203石油钻井液动射液冲击器的性能参数及结构设计上的创新点，测试所获得的排量与压降之间的关系曲线可指导冲击器的使用。生产性试验证明该冲击器工作稳定，可大幅度提高硬地层钻井效率，克服钻柱振动，延长钻柱的使用寿命，具有良好应用前景。     

甘肃陇中盆地会宁关公滩剖面磁性地层年代学研究

本文对陇中盆地会宁含小哺乳动物化石的关公滩剖面河湖相沉积序列进行了详细的岩石磁学和磁性地层学研究,磁化率各向异性结果表明关公滩剖面沉积物记录了典型的原生沉积组构,沉积物沉积以后几乎没有受到后期的扰动.最大磁化率主轴方向与现今的古水流流向基本一致,表明区域西高东低的地貌至少在中更新世早期已经形成.磁滞回线、等温剩磁获得曲线的矫顽力谱分析、三轴等温剩磁退磁曲线等岩石磁学结果显示：关公滩剖面河湖相沉积物的磁性矿物有磁铁矿、磁赤铁矿和赤铁矿,其中磁铁矿和赤铁矿是主要的剩磁载体,但其特征剩磁载体以赤铁矿为主.系统退磁结果显示,在大部分样品中,磁铁矿和赤铁矿均记录了几乎相同的特征剩磁的方向,整个剖面呈现单一的正极性.另外,关公滩剖面底部河湖相沉积物中产出丰富的小哺乳动物牙齿化石,经初步研究包括复齿鼠兔（Ochotonoides complicidens）、丁氏鼢鼠（Myospalax tingi）、方氏鼢鼠（Myospalax fontanieri）、变异仓鼠（Cricetinus varians）、大林姬鼠（Cricetinus varians）、复齿旱獭（Marmota complicidens）等六个种类,其中丁氏鼢鼠和复齿鼠兔是相对原始的种类,其时代跨越早更新世至中更新世早期,其他都是我国北方中、晚更新世常见的种类,该小哺乳动物化石组合性质表明其时代很可能为中更新世早期.因此,综合磁性地层学和小哺乳动物生物年代学结果,关公滩剖面记录了布容正极性时的沉积,剖面底部堆积及其哺乳动物群的时代应为中更新世早期.

     

安徽省旅游政策变迁及其空间 n.响应研究

借助于经济学供给需求分析视角,构建旅游政策变迁及其空间响应的理论框架,根据新制度经济学路径依赖理论和利益集团理论,探寻旅游政策变迁的路径和动因,揭示旅游政策变迁和旅游空间结构发展演化的内在联系。并以安徽省为例,根据改革开放之后安徽省旅游业发展的不同阶段,将旅游政策变迁划分为形成期、密集期和协调融合期3个时期,其空间响应状态分别为点状格局、单一板块格局和多板块空间格局。分析得出,在中国经济体制转轨的背景下,旅游发展由政府主导型向市场主导型转变,旅游政策在不同时期通过其作用机制引导、激励利益主体投资建设旅游节点、交通设施等行为,推动旅游空间格局由点状格局向板块格局发展演化,旅游政策的空间响应强度取决于政府对信息的掌握程度和政策对利益主体的激励程度。     

Mesozooplankton spatial distribution and community structure in the South Adriatic Sea during two winters (2015, 2016)

Whereas the data on mesozooplankton in the epipelagic offshore Mediterranean Sea are extensive, less information is available about plankton in the deeper layers. The present study aims to describe the vertical and horizontal structure and distribution of mesozooplankton species and their associations down to 1,200 m in the water of the Southern Adriatic Sea. Zooplankton were sampled using a Nansen net of 200‐μm mesh size during two cruises in the winters of 2015 and 2016, extending from the coast to the open sea. In total, 203 zooplankton taxa were identified. The community was dominated by copepods, representing between 67% and 91% of the total abundance. The highest total densities were recorded in the upper layers where a high proportion (up to 36%) of appendicularians was also observed in the first sampled year. Five groups of samples were determined based on their community structure. In 2015 communities were distinct between the 0 and 50 m layer and the underlying one (50–100 m), whereas in 2016 epipelagic waters were inhabited by a more uniform mesozooplankton community. The mesopelagic and deep‐water fauna, especially copepods, showed a relatively stable composition in both sampling years Overall, our study confirms the oligotrophic character of the Southern Adriatic, with occasional density outbreaks of appendicularians under favourable conditions.     

钢梁阻尼器的最佳延性率及其控制

基于双线性和三线性的力－位移滞回线假设，导出了钢梁阻尼器隔震系统等效阻尼比与阻尼器延性率的关系；为了获得大阻尼比隔震系统，以尽量减小隔震系统的地震反应，求得了使系统阻尼比为最大的阻尼器相应延性率（即最佳延性率）所需满足的条件；给出了在给定地震地面运动输入条件下，使系统阻尼器变形位移达到最佳延性率的阻尼器初始刚度和屈服位移的确定方法。     

孤立冰块流拖曳系数的优化辨识

流拖曳系数是海冰动力学模型中的重要参数,实际海冰运动时受到水流的底面剪切作用和侧面正压力作用,相应的拖曳系数分别为摩拖曳系数和形拖曳系数。利用实验室波流水槽设备,对长方平底、长方粗糙底和圆饼型淡水冰试样进行拖曳运动试验,获得26组冰样运动数据。根据这些试验数据,利用动量法原理和数学优化方法构造了摩拖曳系数和形拖曳系数的辨识模型,将摩拖曳系数和形拖曳系数两项分开。在此基础上,分析了冰样粗糙度指标(支承长度率和冰厚均方根偏差)对这两个系数的影响;发现了摩拖曳系数同冰样水平尺寸和垂直尺寸之比的关系,该关系能将冰山和浮冰的摩拖曳系数归结到同一条曲线上。     

Runoff change of Naoli River in Northeast China in 1955–2009 and its influencing factors

Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.     

俄罗斯乌多坎砂岩型铜矿的成矿特征与找矿标志

乌多坎砂岩型铜矿是世界知名的超大型砂岩型铜矿之一。总结了该矿床形成的区域地质背景和矿床地质特征,建立了乌多坎砂岩型铜矿的找矿模型与找矿标志,对比了乌多坎砂岩型铜矿床与世界主要著名砂岩型铜矿床的特征,分析了它们之间成矿及赋矿的共同点。结果表明,世界著名的大型-超大型砂岩型铜矿均形成于后造山盆地或地台边缘的盆地(坳陷)中;矿体的规模与形态取决于岩性-岩相条件;矿化类型均具有Cu-Ag矿化特征;均具有干旱的古气候条件及滨海相、三角洲相、海湾-泻湖相的岩相-古地理环境。     

中国海相克拉通盆地内部走滑断裂发育特征及控藏作用

走滑断控油气藏作为一种全新类型油气藏,其勘探潜力已初步显现。在对中国三大海相克拉通盆地内部走滑断裂发育特征与控藏作用开展对比分析的基础上,揭示了塔里木盆地、四川盆地、鄂尔多斯盆地内部走滑断裂空间结构与活动特征的相似性与差异性,并结合盆地动力学演化特征探讨了不同盆地内部走滑断裂成因机制,系统分析了三大盆地内部走滑断裂的控藏作用:(1)中国三大海相克拉通盆地内部均发育中小尺度滑移距走滑断裂,普遍具有“纵向分层,平面分段,垂向多期叠加”的空间结构特征。(2)三大克拉通盆地内部走滑断裂体系具有成因、分布和期次的差异性。塔里木盆地内部走滑断裂体系形成时间早,演化时间长,在盆地北部具有“南北对接,东西分区”特征;鄂尔多斯盆地西南缘受燕山期(侏罗纪—白垩纪)陆内挤压影响,形成了北西西向走滑断裂体系;四川盆地受控于二叠纪峨眉山大地幔柱影响,在盆地内部先存基底断裂基础上,形成了北西向、北西西向、近东西向张扭型走滑断裂。(3)中国三大海相克拉通盆地内部走滑断裂对油气成藏和富集具有重要的控制作用。在控储方面,受断裂-流体耦合改造控制,可形成断控缝洞型储集体、断-溶缝洞型或断控裂缝-孔隙型储集体;在控圈方面,在碳酸盐岩地层中可形成断控缝洞型、断溶缝洞型岩性圈闭;在控运方面,走滑断裂产状高陡,可直接沟通烃源岩和储层,构成重要的油气垂向输导体系。