论北秦岭加里东期造山作用

提出北秦岭加里东造山带由华北地块南缘，以未变质—浅变质沉积岩系为主体的前陆褶断带和北秦岭以中—深变质岩系及强烈岩浆活动为特征的山根带两个主要部分组成。认为它自成体系，相应的变质、变形、岩浆作用发育。该造山带是早古生代未秦岭古洋盆沿商丹—桐柏一线俯冲、消减，促使秦岭古岛弧系碰撞华北地块，造成弧后边缘海闭合所致，是显生宙秦岭造山带形成演化进程中的重大构造事件之一。     

龙门山茂汶─汶川变质带构造特征研究

龙门山中段茂汶─汶川韧性剪切带中可见到绿片岩相到角闪岩相的古生界。该地的巴罗型中压变质相相当于松潘—甘孜褶皱带中地壳的绿泥石带，构成了北东—南西向的茂汶—汶川变质带。雪隆包花岗岩体正位于该变质带的中心部位。三次韧性变形作用（Ｄ１～Ｄ３）造就了印支褶皱带，并在三叠纪末末形成了松潘—甘孜褶皱带。Ｄ１变形作用为北东—南西向的挤压作用和冲断作用，形成了大型的等斜褶皱，使古生界缩短和加厚。在持续的Ｄ２北京—南西向挤压作用下，松潘—甘孜褶皱带和稳定的扬子克拉通之间的差异应变由茂汶—汶川剪切带中非同轴左旋剪切作用所容纳。雪隆包花岗岩体是在Ｄ２变形作用的晚期侵入到剪切带的。产生蓝晶石的变质条件也是在Ｄ２或Ｄ２变形作用后出现的。Ｄ３变形作用为北西—南东向挤压，在局部地方形成糜棱岩状的道冲剪切带。这些特征与绿泥石退变质作用有关，揭示出在Ｄ３变形期间茂汶—汶川变质带有较大幅度的隆升。尽管雪隆包岩体在空间上与茂汶—汶川变质带有关，但作者认为其变质作用是岩层加厚引起的热作用重新达到平衡的产物，而不是由侵入作用引起的热接触变质作用。然而，与岩浆作用伴生的高温和活动性流体仍是产生Ｄ３局部变形和雪隆包岩体隆升的原因，这也是局部出现角闪告相     

线材修磨的磨削压力与砂带速度

本文根据砂带与线材间的接触状态,讨论了砂带修磨线材机理的有关问题,导出了磨削压力、砂带速度与金属去除率之间的关系.试验结果表明;磨削压力的变化对磨削过程具有极为重要的影响,增大磨削压力可大大地提高磨削生产率,降低比磨削能.     

Helium isotopic compositions in fluid inclusions of the Gangxi fault belt in the Huanghua Depression, Bohai Bay Basin

Helium is a trace constituent in natural gases and is the lightest element of all rare gases. Formed during natural nuclear processes, helium is chemically stable. Due to its strong diffusibility and permeability, helium can be used as a very sensitive tracer. Helium has two natural stable isotopes, 3He and 4He. 3He originates from the universal nebulae when the earth was formed, and 4He mainly originates from the radioactive disintegration of elements in the crust, such as U and Th [1]. In…     

提高大面积混凝土墙身外现质量的措施

根据混凝土施工经验,加强对混凝土施工各道工序的把关.针对混凝土墙身表面出现的缺陷,提出施工处理方法和注意事项,使混凝土墙身外观质量有很大提高.     

胶带输送机胶带跑偏的预防

文章主要介绍了胶带输送机在输送散状物料运行过程中,跑偏的几种情况以及应采取的措施.     

热带太平洋和印度洋海温对中国雨带类型的影响

 根据1950~1999年的海温距平和中国夏季(6~8月)雨带分布类型资料,分析了各雨型与前期及同期热带太平洋和印度洋(21°S~21°N,29°E~81°W)海温异常的相关关系.分析表明,不同雨带类型和所对应同期及前期太平洋和印度洋海温有很好的相关关系.     

浅谈长江上游经济带的地位和作用

在经济全球化的条件下，区域经济一体化是全面推进工业化与城市化进程的必然选择．谁能在区域经济一体化的发展进程中占有先机，谁就能在经济全球化的竞争中获胜．在此背景下，准确把握长江上游经济带的地位和作用显得尤为重要．本文通过对长江上游经济带特征的分析，从全国生产力布局、西部大开发战略和长江流域经济开发三个方面对长江上游经济带的地位和作用进行了论述．     

浅谈长江上游经济带的地位和作用

在经济全球化的条件下,区域经济一体化是全面推进工业化与城市化进程的必然选择.谁能在区域经济一体化的发展进程中占有先机,谁就能在经济全球化的竞争中获胜.在此背景下,准确把握长江上游经济带的地位和作用显得尤为重要.本文通过对长江上游经济带特征的分析,从全国生产力布局、西部大开发战略和长江流域经济开发三个方面对长江上游经济带的地位和作用进行了论述.     

Geochemical characteristics and tectonic implications of HP-UHP eclogites and blueschists in southwestern Tianshan, China

Four rock assemblages in correspondence with two different tectonic settings have been recognized in the NEE-SWW extending HP-UHP metamorphic belt in southwestern Tianshan, northwest China. Eclogite assemblage EC1 is geochemically akin to alkaline within-plate oceanic island basalt (OIB). EC2 shows affinity to enriched mid-oceanic ridge basalt (EMORB). Rare earth element (REE) and other immobile trace element characteristics of blueschist assemblage BS1 resemble those of normal mid-oceanic ridge basalt (NMORB). These three assemblages are likely formed on a seamount setting, and the prevalent presence of carbonate minerals and omphacite quartzite stripes/gobbets suggests ancient pelagic sediments including marls are probably developed upon the basaltic seamount. Whereas the geochemical characteristics of BS2 assemblage are of volcanic arc basalt-type. The seamount with the pelagic sediments on it is brought into the subduction zone, and volcanic arc basalts formed on the active continental margin and trench sediments are eroded and enwrapped in the subducting mass, they are altogether subjected to high to ultrahigh pressure metamorphism and subsequent exhumation towards surface. The HP-UHP metamorphic belt is thus interpreted as a subduction-accretionary complex formed by tectonic juxtaposition and imbrication of seamount, seafloor, trench and volcanic arc sequences during oceanic crust subduction.