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481.
Masatoshi Yamada Tatsuo Aono Jian Zheng 《中国地球化学学报》2006,25(B08):162-162
Settling particles were collected from six stations at the Okinawa Trough and the East China Sea continental margin. Activities of U, Th, Pu isotopes and ^210Pb were determined for the particles to elucidate their transport processes. Surface sediment samples were also analyzed for their isotopes. There was a tendency for ^210Pb activities to increase almost linearly with depth from 72 m on the continental shelf edge to 1019 m in the Okinawa Trough. Increasing ^210Pb activities in settling particles with depth on the continental margin may be attributable to enhanced ^210Pb scavenging by particles and removal near the front. There also was a clear tendency for total mass fluxes and the radionuclide fluxes to increase with depth, with an especially large increase near the bottom. The ratio of the observed ^210Pb flux to the ^210Pb deficiency flux in the near-bottom traps ranged between 8.9 and 46. These high values show a strong ^210Pb excess which would be attributable to large advective import to the near-bottom and resuspended particles that have settled through the water column but have not been incorporated into the sediments. High variability of radionuclide fluxes occurred in very short time periods. Activities of ^238U, ^232Th, ^230Th, ^228Th, ^210Pb and ^239Pu+^240Pu in settling particles were significantly higher than those in the underlying surface sediments. 相似文献
482.
微量元素谱图油气评价技术是在引进俄罗斯地电化学油气勘探方法的基础上开发的一项含油气性及油气属性评价预测新技术。试验研究表明,油区内外土样电化学提取微量元素Ti、V、Cr、Mn、Co、Ni、Cu、Zn的ICP质谱特征存在特征差异。利用微量元素谱图特征在五谷城和姬塬地区进行了油气评价和有利目标预测。地电化学微量元素谱图相关系数异常与微量元素浓度异常及烃类异常有较好的配置关系,与自然电位和可控源音频大地电磁确定的有效砂体储层相对应。2001及2002年在五谷城和姬塬地区微量元素谱图油气评价预测的有利区内及附近钻获油流,证实了微量元素谱图油气评价在长庆岩性油藏勘探中的作用及有效性。 相似文献
483.
484.
485.
川西坳陷中段须家河组四段钙屑砂岩气层的成因 总被引:3,自引:0,他引:3
钙屑砂岩在川西坳陷须家河组四段分布特别广,几乎每个构造、每口井都能见到。岩石大部分致密,目前只在局部井段见到孔隙发育能成为有效储集层。在大量岩石薄片鉴定及资料统计的基础上,对丰谷地区钙屑砂岩的岩石学、成岩作用、储集物性和孔隙发育特征进行了详细的研究。结果表明,丰谷地区钙屑砂岩气层单层砂体厚度大,碳酸盐岩岩屑含量高,方解石胶结物含量低,次生孔隙发育,孔隙类型主要为溶蚀粒间孔。天然气主要来自下三叠统马鞍塘组、须家河组三段、须家河组四中亚段烃源岩。本区钙屑砂岩气层与所经历成岩作用密切相关,属于成岩圈闭型气层。丰谷地区钙屑砂岩气层的形成过程对于勘探类似岩性气藏具有借鉴与指导意义。 相似文献
486.
The taxonomic composition and types of particles comprising the downward particle flux were examined during the mesoscale artificial iron fertilisation experiment LOHAFEX. The experiment was conducted in low-silicate waters of the Atlantic Sector of the Southern Ocean during austral summer (January–March 2009), and induced a bloom dominated by small flagellates. Downward particle flux was low throughout the experiment, and not enhanced by addition of iron; neutrally buoyant sediment traps contained mostly faecal pellets and faecal material apparently reprocessed by mesozooplankton. TEP fluxes were low, ≤5 mg GX eq. m−2 d−1, and a few phytodetrital aggregates were found in the sediment traps. Only a few per cent of the POC flux was found in the traps consisting of intact protist plankton, although remains of taxa with hard body parts (diatoms, tintinnids, thecate dinoflagellates and foraminifera) were numerous, far more so than intact specimens of these taxa. Nevertheless, many small flagellates and coccoid cells, belonging to the pico- and nanoplankton, were found in the traps, and these small, soft-bodied cells probably contributed the majority of downward POC flux via mesozooplankton grazing and faecal pellet export. TEP likely played an important role by aggregating these small cells, and making them more readily available to mesozooplankton grazers. 相似文献
487.
We examined metal (Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb) and particulate organic carbon (OC) concentrations of the marine vertical export flux at the DYFAMED time-series station in the Northwestern Mediterranean Sea. We present here the first data set of natural and anthropogenic metals from sediment trap moorings deployed at 1000 m-depth between 2003 and 2007 at the DYFAMED site. A highly significant correlation was observed between most metal concentrations, whatever the nature and emission source of the metal. Cu, Zn and Cd exhibit different behaviors, presumably due to their high solubility and complexation with organic ligands. The observed difference of atmospheric and marine fluxes in terms of temporal variability and elemental concentration suggests that dense water convection and primary production and not atmospheric deposition control the marine vertical export flux. This argument is strengthened by the fact that significant Saharan dust events did not result in concomitant marine vertical export fluxes nor did they generate significant changes in metal concentrations of trapped particles. 相似文献
488.
结合区域地震剖面解析和沙箱模拟实验,探讨分析了乍得Bongor盆地反转构造特征及其形成机制。结果表明:(1)
Bongor盆地中发育三种典型的反转构造类型:挤压反转单斜构造、挤压反转向斜构造和挤压反转背斜构造。该类反转构造
一部分具有反转断层相关褶皱样式,主要沿高角度边界断层和基底地垒边界断面发育,形成演化与断裂活动息息相关,另
一部分呈散花状背斜构造样式,属于地层纵弯上拱褶皱,主要发育于斜坡断阶带之间;(2) 区域剥蚀作用对盆地反转构造
演化具有重要的影响,其对盆地内深部地层反转褶皱发育具有促进作用,为深部构造圈闭形成提供条件,而对浅部地层的
反转褶皱发育则表现出阻碍或破坏作用,不利于浅层构造圈闭的形成。 相似文献