Paleoproterozoic (ca. 1.7 Ga) magmatism in Chifeng,Inner Mongolia: implications for the tectonic evolution of the Trans-North China Orogen

The Meilin porphyritic biotite granite is located along the northern margin of the North China Craton and the northern central orogenic belt. The Meilin granite is complex but is dominated by a porphyritic biotite granite. Isotopic dating using zircon U-Pb LA-ICP-MS analyses indicates that the porphyritic biotite granite was emplaced at 1715.6 ± 9.6 Ma during the Late Paleoproterozoic, rather than during the Permian as previously thought. The Meilin granite is an A-type, and all samples from this granite are characterized by relatively high contents of silica (SiO₂ = 69.86–71.70%), alkalis ((Na₂O + K₂O) = 8.69–9.40%), alumina (Al₂O₃ = 13.71–14.59%), high ratios of FeOt/MgO, low contents of calcium (CaO = 0.26–0.39%), and a negative Eu anomaly (Eu = 0.47–0.57). Additionally, all samples display strong enrichment in Th, K, La, Ce, and P and depletion in U, Ti, Ta, and Nb. These characteristics indicate that the granite formed in a rift environment, where rifting caused mantle decompression and the formation of basic magma. Underplating of the basic magma provided a heat source, leading to the partial melting of the lower crust. Sr isotopes of the Meilin porphyritic biotite granite suggest that the magma source was the remelting of the metamorphic basement. The granite was therefore emplaced in a non-orogenic extensional tectonic setting, which may have been related to the initial breakup of the Columbia supercontinent during the Late Paleoproterozoic.     

河南箕山登封岩群变质中基性火山岩的地球化学及年代学研究

对登封岩群 TTG杂岩区内的斜长角闪质表壳岩包体以及绿岩区的变质中基性火山岩对比研究表明 ,其主元素、微量元素、稀土元素和同位素地球化学特征等指示该区的变质中基性火山岩同时同源 ,具有由拉斑玄武岩向钙碱性玄武岩演变的趋势.登封岩群上下部 2件 Sm Nd等时线年龄极为一致 ,可以合并为一条等时线 ,年龄为 (2 512± 19) Ma,ε Nd(t)=2.40± 0.16.综合分析认为 ,箕山地区的登封岩群稍晚于嵩山地区 ,是在新太古代末期一个非常短暂的时间内形成的 ,形成于类似现代岛弧的构造环境.     

地震烈度分布快速产出发展概况

通过对实时地震仪的数据采集,和新开发的地面运动参数和期望的震动烈度值之间的关系,美国已经实现了仪器地面运动和震动烈度图的快速(3～5min)产出。整个南加州震动值的估计是通过空间测量的地面运动的插值来完成的;插值是基于频率和依赖于振幅的台站修正的。震动图的产出是自动的;通过在南加州的重大地震来触发。通过因特网,公众和科学用途的震动图可以在几分钟内得到;对于紧急响应机构和应急用户,通过数据通信专线可以快速得到这些图。     

河南商城汤泉池温泉电阻率成像

电阻率成像法在地热勘查中,可以客观较真实地反映断层、热储地质体的基本特征.本文阐述了地电成像的原理、方法以及汤泉池温泉地热地质条件,对4条电阻率成像剖面进行了解释及综合分析,为定井提供了依据.     

钻孔灌注桩的超声波检测

结合焦郑高速公路钻孔灌注桩的超声波检测,对超声波检测的原理、方法以及桩身缺陷的判定进行了介绍和分析,通过实例证明超声波检测法能准确判断出桩身缺陷的位置和范围,并能对缺陷严重程度做出评价,是检测灌注桩桩身质量的一种较好方法.     

Qinling Faunal Region-The Third Ordovician Faunal Region: International Correlation

The Ordovician conodont faunal provinces were previously divided into the Midcontinent and Atlantic Faunal Regions situated respectively in low and high latitudes, where warm- and cold-water type conodont faunas flourished respectively. According to the international correlation this paper proposes the third Ordovician conodont faunal region-Qinling Faunal Region, in which cold-water conodont faunas were well developed in the Early to middle Middle Ordovician and warm-water conodont faunas were well developed in the late Middle and Late Ordovician, indicating that the Qinling Region was situated in high latitudes earlier and in low latitudes later. The origin was only due to plate movement In the Qinling Region the time interval of the change of the conodont fauna from the cold- to warm-water type was 4 Ma (from 474 to 470 Ma), during which the fauna geographically spanned 40° of latitudes, with a movement velocity of nearly 1.12 m/a, indicating that the high-latitude plates were divorced and reduced i     

河南东濮凹陷古近系沙河街组盐岩沉积特征及成因

东濮凹陷是渤海湾盆地的一个次级构造单元，其古近系的两个沉积旋回发育了四套盐岩，分别位于沙河街组第三段的第四亚段(S34)、第三亚段(S33)、第二亚段(S32)和沙河街组的第一段(S1)。主要分布在凹陷北部。每套盐岩又由若干个盐韵律组成，每一单韵律由盐岩和泥岩组成。两套等时对比标志层（深湖沉积）之间盐岩与砂泥岩存在着相变关系。盐岩是在深盆背景下干旱成因的，盐类物质来自地下深处上涌的卤水，分层卤水是盐形成的基本形式，上涌通道是基底大断裂，动力基础是岩浆活动。盐的阻隔作用使其对下部地层的温度、压力均有影响，这种影响有利于加快盐下地层中的有机质成熟与演化。盐又是良好的盖层，且在高温、高压下盐呈塑性状态。勘探实践看出东濮凹陷的岩性油气藏与盐岩的沉积有密切的关系，因此搞清盐岩的分布规律对东濮凹陷下步勘探有着极为重要的意义。     

河南濮阳西水坡新石器时代遗址瓣鳃类动物群的生态环境分析

河南濮阳西水坡新石器时代遗址出土的瓣鳃类共有33种，其中31种组成了Lamprotula-Cuneopsis-Unio组合，称为西水坡丽蚌动物群，其时代为中全新世早期。据贝壳14C测年资料（6 465±45 a BP）和同层出土的陶器特征， 为仰韶文化早期（7 000～6 000 a BP）。该动物群与长江中,下游流域洞庭湖、鄱阳湖和太湖及其周围水域的现代丽蚌动物群组合特征非常接近，同属东洋界、中印亚界动物地理区， 亚热带湿热气候。根据该动物群反映的生态环境，仰韶文化早期该地区的古环境地处亚热带，气候湿热，雨量充沛，草木茂盛，河流成网，湖泊遍野，水质优良，水生生物丰富，优越的自然环境为先民提供了从事农耕、渔猎的生栖条件。     

泌阳凹陷安棚油田核三段储层天然裂缝特征研究

根据岩芯裂缝观察结果,通过与FMI,MAIN成像测井资料进行对比,系统描述天然裂缝在成像测井上的影像特征,对地层裂缝特征参数进行了确定.成果反映出核三段地层中的裂缝主要为垂直裂缝倾角在80°～90°之间.走向在100°～110°左右,宽度一般小于1 mm,裂缝长度主要在30 mm以内.     

河南卢氏—栾川地区铅锌矿成矿多样性分析及成矿预测

河南省卢氏-栾川地区位于华北陆块南缘与秦岭造山带的衔接部位,是中国重要的钼、钨、铅、锌多金属成矿区。通过控矿地质条件与成矿环境多样性分析,将研究区铅锌矿划分为3种成因类型:岩浆热液交代型铅锌矿床、MVT型铅锌矿床和SEDEX型铅锌矿床。在此基础上,利用“成矿专属性”和“成矿多样性”相结合的找矿思路,对矿区不同类型矿床成矿进行远景评价,指出具有良好的找矿前景。