因子分析法对内蒙古查巴奇地区水系沉积物地球化学分区的应用研究

利用R型因子分析方法对内蒙古查巴奇地区1∶5万水系沉积物数据资料进行分析,提取了具有代表性的8个因子,绘制了因子得分图及地球化学分区图,结果显示:地球化学分区结果与地质特征对应较好。As、Sb、Cu、Zn组合主要反映了林西组地层,其子区展布方向与林西组地层的NE走向一致,而Pb、Zn子区在光华组英安岩及安山岩、老龙头组变质岩和早侏罗世英云闪长岩中均有分布,总体呈NE向展布;Ag、W子区除在研究区北侧有相对较小面积的分布外,主要分布在研究区南部晚侏罗世二长花岗岩中,表明Ag、W类与该位置的花岗岩体密切相关。通过野外实际调查发现,一个Au矿点及一个Pb、Zn矿点分别位于As、Sb、Cu、Zn子区和Pb、Zn子区内。通过对研究区进行地球化学分区,明确了各类子区特定的地质地球化学意义及其相互关系,为勘查地球化学方法找矿提供有利信息。     

松辽盆地地浸砂岩型铀成矿铀源分析

通过研究松辽盆地钱家店铀矿床和盆地南部铀矿化认为,松辽盆地砂岩型铀成矿作用独特,其成因可归结为双混合叠造型。其铀源也具有多源性,既有蚀源区铀源,又有盖层铀源,还有深部铀源,它们共同组成松辽盆地铀成矿的铀源。     

精细地球化学找矿方法的一次实践——以江西九江城门山铜矿外围联盟银金矿化点的发现为例

结合本次城门山铜矿东南侧联盟银金矿化点的发现,论述了开展精细地球化学找矿的重要性,即遵循"以矿找矿"和铜多金属矿床的时、空套叠成矿作用的准则,以地质为基础,以现代地球化学成矿成晕机制为指导,以勘查地球化学新技术、新方法和高精度的分折测试为支撑,在老矿区的深部和外围开展新一轮的地球化学找矿方法研究。     

Calcium carbonate precipitation induced by a bacterium strain isolated from an oligotrophic cave in Central China

A heterotrophic Bacillus sp. strain (5C-1) was isolated from Heshang cave, an oligotrophic karst cave in the middle reaches of Yangtze River, and identified by BIOLOG and 16S rDNA sequencing. Bacterially induced formation of calcium carbonate by 5C-1 was investigated in several comparative experimental sets with or without the cell and extracellular enzymes. The temporal variations of both the amount of the precipitates and the pH values of the solution were measured by a spectrophotometer and a pH meter, respectively. The morphological characteristics of the calcium carbonate precipitates were observed with environmental scanning electronic microscopy (ESEM). The growth of 5C-1 was found to greatly promote the pH value of the liquid medium in the first 2 days, which favors the formation of calcium carbonate. No precipitates were formed with the pH value lower than 8.6, though the pH value was demonstrated to be not the only factor controlling the formation of the calcium carbonate. The accumulation of extracellular polysaccharide substance was observed to favor the precipitate formation. Only when both factors reached a threshold did the precipitates form with the addition of CaCl₂. Cells and extracellular enzymes were not the factors that limit the precipitate formation in our microbial systems. The precipitates of a variety of morphological features including dumb bells, peanuts, irregular and spherical and rhombic forms were mainly observed in our microbial systems but not in the chemical control system. Interestingly, imprints of bacterial cells and spores were observed to be present on the surface of the precipitates of a peanut or a dumb bell form, probably indicative of the microbial escaping mechanism during the mineralization of calcium carbonate.     

用于构建生物系统发育树的古DNA序列

主要综述了古 DNA研究进展以及结合古 DNA序列和基因库中的数据构建系统发育树。这些研究能解决许多有关演化生物学、考古学、人类演化及迁移、动植物的家养和驯化过程及早期农业的发展、考古点的动植物残骸的精确鉴定及地质演化等问题。另外 ,还列举了一些重要的实例     

利用Access97编制科技论文登记及统计数据库

介绍利用Access97编制科技论文登记数据库的具体过程及使用方法。通过该数据库，可以及时将发表的科技论文入库。当论文全部入库后，可以方便地进行查询及统计，从而得出有效的数据，大大提高了工作效率。     

江西煤炭资源勘查现状及前景分析

江西煤田地质勘探的形势是严峻的，后备煤炭资源严重不足。无可供建井设计利用的精查储量，无可供精查的详查储量，可供详查的普查储量少，可供普查的找煤储量更少。地质勘探的找煤、普查与详查比例严重失调，许多矿井又面临资源枯竭、按替困难的局面。江西仍有较多的煤田勘探靶区需要勘探验证，煤炭工业有广阔的市场。希望政府采取各种措施加大对煤田地质勘探的投入。     

冀北地区岩石极化率特征及其找矿意义

介绍在东经114°～120°和北纬39°00′～42°30′的范围内岩石极化率研究的成果。数值统计结果显示,798件沉积岩的平均极化率为2.40%,1149件火成岩的极化率为2.99%,436件变质岩的极化率为3.59%,因此,变质岩是本区较好的金属矿矿源。空间分布上,与沉积作用密切相关的煤矿主要分布在沉积岩高极化率地区,变质铁矿主要分布在变质岩高极化率地区,内生金矿则主要分布在火成岩高极化率地区。因此认为,主要矿产地的分布与极化率高值区的分布在空间上大体一致,岩石极化率反映了矿源物质的总体背景。     

Devonian Frasnian-Famennian Transitional Milankovitch Cycles and High-Resolution Stratigraphic Correlation

Four hierarchical cyclothems, superbundlesets, bundlesets, bundles and laminae, have been identified from the Devonian Frasnian-Famennian carbonate strata in Guangxi, South China. Their hierarchical structures, ratio relationships and sequence in conodont zones are continuous and stable and can be traced across different facies zones and sedimentary basins. Our data show that hierarchically organized superbundlesets, bundlesets, bundles and laminae correspond to the long eccentricity, eccentricity, obliquity or precession and sub-Milankovitch cycles respectively. Their periods were 400,000, 100,000, 33,333, 16,667 and 8,000-17,000 a, respectively. The ratios of long eccentricity to eccentricity, eccentricity to obliquity, and eccentricity to precession in the Devonian are 1:4, 1:3 and 1:6 respectively. Using these hierarchical Milankovitch cyclothems, chronostratigraphical division and correlation can be realized at a resolution of 100 ka or 10 ka at the Frasnian-Famennian transition. The time intervals     

折射波地震记录叠加成像方法研究

多次覆盖折射波地震勘探是用来追踪反射波成像质量较差地区的地质构造或用于追踪深层基底形态及研究基岩面的一种勘探方法.基于折射波理论，用折射地震记录中的折射波对地下折射界面进行成像，应用共深度折射面元叠加成像理论方法，给出用共深度折射面元叠加成像技术对地下折射界面进行成像的速度分析与动校正计算方法，提出一种适用于折射波发育探区的共深度折射点叠加成像方法，最后以模型和实际例子说明方法的正确性和实用性.