对于点苍山-石鼓变质带区域划分的意见

在以往的研究中,点苍山和哀牢山被认为是同一个变质带。对石鼓带的划分也有很大争议。本文通过岩石学和同位素年代学的研究,认为点苍山和石鼓变质带同为扬子基底的一部分,应属于滇东变质区。它们是在元谋-大红山群之上发育的一套中晚元古变质岩带,具陆内地台型火山-沉积的特点。     

Ultra-high pressure metamorphic rocks in the Dabie-Su-Lu region, China: Their formation and exhumation

Abstract Based on petrological, structural, geological and geochronological research, the authors summarize the progress of ultra-high pressure (UHP) metamorphic rock study since 1989 by Chinese geoscientists and foreign geoscientists in the Dabie-Su-Lu region. The authors introduce and discuss a two-stage exhumation process for the UHP metamorphic rocks that have various lithologies; eclogite, ultramafics, jadeitic quartzite, gneiss, schist and marble. The metamorphic history of UHP metamorphic rocks is divided into three stages, that is, the pre-eclogite stage, coesite eclogite stage, and retrograde stage. Prior to UHP metamorphism, the ultramafics had a high temperature environment assemblage of mantle and others had blueschist facies assemblages. The granulite facies assemblages, which have recorded a temperature increase event with decompression, have developed locally in the Weihai basaltic rocks. Isotopic ages show a long range from > 700 Ma to 200 Ma. The diversity in protoliths of UHP metamorphic rocks may be related to the variation of isotopic ages older than 400 Ma. The Sm-Nd dating of ~ 220 Ma could reflect the initial exhumation stage after the peak UHP metamorphism in relation to the collision between the Sino-Korean and Yangtze blocks and subsequent events. Petrological and structural evidence imply a two-stage exhumation process. During the initial exhumation, the UHP metamorphic rocks were sheared and squeezed up in a high P/T regime. In the second exhumation stage the UHP metamorphic rocks were uplifted and eventually exposed with middle crustal rocks.     

Ultrahigh-pressure garnet lherzolite from Chijiadian, Rongcheng County, in the Su-Lu region of eastern China

Abstract Petrological studies of a serpentinized garnet lherzolite body in Rongcheng of the Su-Lu region of eastern China revealed unusually high pressure. Spinel lherzolite probably in a subducting slab was transformed to garnet lherzolite at mantle depth. During exhumation, they were subsequently subjected to the granulite and then amphibolite overprinting and a phase of serpentinization. The peak P–T conditions of the garnet lherzolite estimated after detailed analysis of the metamorphic texture are 4–5 GPa and 820°C or 5–6 GPa and 780°C, depending on the chosen geothermobarometers. The lower dP/dT of the garnet lherzolite can be interpreted as the results of subduction of an old (say 100 Ma older than the time of collision) and cold, slab underneath the margin of the Sino–Korean craton.     

应用遥感数据研究中国植被生态系统与气候的关系

应用1982-1994年NOAA/AVHRR的归一化植被指数（NDVI）资料和587个气象台站的数据对我国不同类型植被生态系统和气候的关系进行研究，首先将我国的植被类型划分为21类，在此基础上分别研究了不同时间尺度下我国不同区域，不同植被类型和气候的关系。结果表明：在多年平均状态下，植被生态系统NDVI水平主要受水分条件的影响；年内变化上，温度对植被生态系统季相变化化起着比降水略大的作用，年降水量造成了植被季相响应的差异，在年际变化上，分别研究了4个季节和整个生长期尺度上的关系，一般情形为温度和降水对植被的年际波动起着大致相反的作用，不同植被类型在不同的生长时期（季节）对气候的变化响应方式也不同，发现在植被的生长期，我国南方和北方的植被生态系统对温度和降水的响应方式相反；同时存在2个植被-气候敏感区，分别为我国北方的典型草原到森林的过渡区和云南中部部分区域。     

在砂土液化的危险性评价中确定性与不确定性方法的应用研究

地震导致的砂土液化具有很大的随机性。据此 ,提出了评价砂土液化危险性的确定性与不确定性两种方法。确定性方法是以液化指数为变量的多因子判别分析方法 ,不确定性方法是概率分析法 ,即用概率密度函数判断砂土液化灾害的期望损失值。     

鄂尔多斯盆地奥陶系热水岩溶特征

鄂尔多斯盆地奥陶系深部白云岩中的溶蚀孔洞,其成因属于热水岩溶作用的结果。本文通过成因矿物学及Fe2+ 、Mn微量元素分析和气液包裹体测定,结合岩溶发育的构造背景,深入揭示了本区热水的来源主要为深部循环热水,局部尚有深部上升的热液加入 ;其热能除地温梯度加热、构造运动加热外,在盆地基底古断裂附近可能还有深部热源的影响而形成的中低焓地热流体。充填矿物包裹体均一温度为 15 0～ 34 9℃,气相成分中CO₂ 摩尔浓度达到44.3%～ 5 6.98%。Fe2+ 、Mn微量元素在鄂 6、定探 1、李华 1井、芦参 1井、陕 8井和旬探 1井白云岩中的富集,指示了这些井区是热水运移的主要近源区。认为热水岩溶的发育,对奥陶系内幕储层的形成具有重要意义     

鲁东-苏北榴辉岩的构造特征及其折返机制

鲁东-苏北地区出露了M型和Q型两类榴辉岩,前者的原岩为地幔岩类,后者的原岩为地壳岩类。它们均呈外来岩块产出于片麻岩中。其形成经历了前榴辉岩I、A和S阶段,在I和A阶段它们表现为韧性变形,而在S阶段则表现为碎裂变形。它们的折返过程经历了剪切回流和区域性隆起剥蚀。     

江苏省风能资源重新估算与分布研究

利用1971—2000年江苏省67个台站的多气象要素资料,挑选风能资源评估的代表年,重新计算江苏省风能资源状况,发现与上世纪80年代全国风能评估结果以及90年代的评估结果有很大差异,全省风能总储量估算为3.03×1010W,实际可开发量约为0.24×1010W。风能资源在江苏沿海和海岛比较丰富,是未来开发的重点区域,而在绝大部分内陆地区风能贫乏,贫乏区占据全省的92.2%。     

我国东部新生代玄武岩岩石化学的一些探讨

新生代是地球上玄武质岩浆的主要活动期。在我国东部,新生代玄武岩分布也极广泛,由北往南自大兴安岭、松辽盆地经华北、苏闽浙至台湾、海南岛以及近海大陆架均有不同程度的出露。时间上从老第三纪至史期均有玄武岩喷发活动。     

Lg Coda Q and its Relation to the Geology and Tectonics of the Middle East

—Regional seismograms were collected to image the lateral variations of Lg coda Q at 1 Hz (Q ₀?) and its frequency dependence <(eta)> in the Middle East using a back-projection method. The data include 124 vertical-component traces recorded at 10 stations during the period 1986–1996. The resulting images reveal lateral variations in both Q ₀ and <eta>. In the Turkish and Iranian Plateaus, a highly deformed and tectonically active region, Q ₀ ranges between about 150 and 300, with the lowest values occurring in western Anatolia where extremely high heat flow has been measured. The low Q ₀ values found in this region agree with those found in other tectonically active regions of the world. Throughout most of the Arabian Peninsula, a relatively stable region, Q ₀ varies between 350 and 450, being highest in the shield area and lowest in the eastern basins. All values are considerably lower than those found in most other stable regions. Low Q values throughout the Middle East may be caused by interstitial fluids that have migrated to the crust from the upper mantle, where they were probably generated by hydrothermal reactions at elevated temperatures known to occur there. Low Q ₀ values (about 250) are also found in the Oman folded zone, a region with thick sedimentary deposits. <eta> varies inversely with Q ₀ throughout most of the Middle East, with lower values (0.4–0.5) in the Arabian Peninsula and higher values (0.6–0.8) in Iran and Turkey. Q ₀ and <eta> are both low in the Oman folded zone and western Anatolia.