The effects of surface area, grain size and mineralogy on organic matter sedimentation and preservation across the modern Squamish Delta, British Columbia: the potential role of sediment surface area in the formation of petroleum source rocks

Surface sediment samples were collected from the Squamish River Delta, British Columbia, in order to determine the role of sediment surface area in the preservation of organic matter (OM) in a paralic sedimentary environment. The Squamish Delta is an actively prograding delta, located at the head of Howe Sound.Bulk total organic carbon (TOC) values across the Squamish Delta are low, ranging from 0.1 to 1.0 wt.%. The carbon/total nitrogen ratio (C_org/N) ranges from 6 to 17, which is attributed to changes in OM type and facies variations. The <25-μm fraction has TOC concentrations up to 2.0 wt.%, and a C_org/N ratio that ranges from 14 to 16. The 53–106-μm fraction has higher TOC concentrations and C_org/N ratios relative to the 25–53-μm fraction. The C_org/N ratio ranges from 9 to 18 in the 53–106-μm fraction and 5.5–10.5 in the 25–53-μm fraction. Surface area values for bulk sediments are low (0.5–3.0 m²/g) due to the large proportion of silt size material. Good correlation between surface area and TOC in bulk samples suggests that OM is adsorbed to mineral surfaces. Similar relationships between surface area and TOC were observed in size-fractionated samples. Mineralogy and elemental composition did not correlate with TOC concentration.The relationships between surface area, TOC and total nitrogen (TN) can be linked to the hydrodynamic and sedimentological conditions of the Squamish Delta. As a result, the Squamish Delta is a useful modern analogue for the formation of petroleum source rocks in ancient deltaic environments, where TOC concentrations are often significantly lower than those in source rocks formed in other geological settings.     

中国东南沿海中-新生代玄武岩微量元素和Nd-Sr-Pb同位素研究

本文对中国东南沿海不含幔源包体的中生代玄武岩和含幔源包体的新生代玄武岩进行了微量元素和Nd-Sr-Pb同位素对比研究。中生代玄武岩呈Ta、Nb和Hf负异常,低Ce/Pb、Nb/U比值和高La/Nb比值,与岛弧火山岩和陆壳岩石的微量元素特征相类似,说明在岩浆生成和上升过程中,幔源组分受到了陆壳组分的混染。新生代玄武岩呈Ta、Nb正异常和Pb负异常,高Ce/Pb、Nb/U比值和低La/Nb比值,与海岛玄武岩(OIB)相类似,Nd-Sr同位素成分与夏威夷玄武岩类似,因而它们未受明显的陆壳混染。143Nd/144Nd与206Pb/204Pb之间的负相关关系和87Sr/86Sr与206Pb/204Pb之间的正相关关系说明本区新生代玄武岩起源于中等亏损程度的软流圈地幔,并与EMII富集地幔组分发生了混合。     

高密度电法在湘西北岩溶石山区找水中的应用

湘西北岩溶石山区地质构造复杂，岩溶发育且具分布不均匀性，找水难度大，为提高含水构造的异常分辨力，各种物探方法的优化组合中，以高密度电法在确定最佳井位方面发挥了重要作用，它采集的数据量大，对异常特征反映灵敏度高，在湘西北不同的岩溶水文系统中找水，取得了成功的范例。     

插值计算不规则图形面积的方法选择

采用实际的不规则图形作为评价图形，讨论了几种不同插值方法的面积计算精度，得出了对实际工作指导意义的结论。     

SOME NEW UNDERSTANDINGS OF LAND-SURFACE PROCESSES IN ARID AREA FROM THE HEIFE

The survey for the HEIFE(Atmosphere-Land Surface Processes Experiment at Heihe RiverBasin,Western China)is given in the paper.The following basic subjects for land-surface process-es in arid areas are studied:(1)the general characteristics of the energy budget on ground surfacein arid areas;(2)the parameterization of the land surface processes;(3)the interaction betweenoasis and its desert circumstances,a special phenomenon in arid areas.The analysis shows that thesensible heat flux in the surface energy budget is in the majority,and the latent heat flux may beneglected.The influence of atmospheric stratification stability on the turbulent transfer of energyand substance must be considered in parameterization of land surface processes in arid areas.The“cold island effect”phenomenon in oasis and the“humidity inversion”phenomenon in desert nearoasis are the result of the interaction between them.The results would improve the understandingof land surface processes in arid areas.     

地震断层气监测的现状与展望

断层气测量是地震科学研究的重要方法之一，断层气测量具有实用、轻便、快便、价廉等优点，在地震监测预报和减灾活动中具有广阔的应用前景和巨大的潜力。本文对断层气测量在地震科学中的应用和现状作了简要的介绍，同时探讨了我国地震断层气监测系统中存在的一些主要问题，对今后的发展进行了展望。最后简单介绍了几种断层气监测新技术及新型气敏传感器。     

塔里木北部地区岩石物性参数测试和区域层滑系统的确定

为了定量地研究塔里木北部地区区域的层次结构．拆离构造，特别是同油气地质、圈闭构造密切相关的沉积盖层中的层滑倾滑和推覆滑覆等各种构造的形成机制，对该区沉积盖层进行了较系统的岩石物性和岩石力学标本采集和测试（包括三轴参照实验）．依其参数结构特点和地质、物探资料，划分出４套７层区域性层滑系统，并与研究程度较高的中、下扬子区的物性参数、岩性组合和构造特征进行综合对比．最后还进一步阐明了塔里木北部地区特征的前列式冲断构造和含油气局部构造等，均受到这７层区域层滑系统的制约．     

苍山5．2级地震前地震波速比的异常变化

本文对苍山５．２级地震前，鲁南地区地震波速比的时、空分布特征进行了分析，发现５．２级地震前，该区波速比的时、空分布都出现了较明显的低值异常。时间分布的异常形态为下降—低值—恢复—发震。空间分布则为近似圆形的低值异常区。异常区外围地区显示地震平静。苍山５．２级地震前，我们曾根据该区的波速比异常变化，对鲁南地区提出了预报意见。     

东昆仑活动断裂带的强震构造条件及未来强震危险区分析

通过对东昆仑活动断裂带强震构造条件的研究发现，这条断裂带的强震构造条件不仅与所处的区域地壳运动状况有关，而且与该活动断裂带的规模、形态，断裂带的构造组合及断裂带的运动条件等密切相关。在研究了东昆仑活动断裂带强震构造条件的基础上，还沿断裂带划出了三个未来强震危险区。