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461.
462.
Indicators as a means of communicating knowledge 总被引:3,自引:1,他引:3
463.
464.
Fulton Elizabeth A.; Smith Anthony D.M.; Punt Andre E. 《ICES Journal of Marine Science》2005,62(3):540-551
465.
Thermal indicator data are used in an inverse mode to determine ages of stratigraphic horizons simultaneously with paleoheat flux. Results from blind tests on wells with horizon ages ranging from Ordovician through Carboniferous and Jurassic to Miocene indicate that thermal indicator inversions are capable of resolving such ages to within about 10% uncertainty. Results using the inversion procedure with one thermal indicator (vitrinite reflectance) were comparable to the results using another independent thermal indicator (sterane isomerization) in the same well. The activation energy for sterane isomerization was determined to be 30±15 kJ mol–1. In addition: (a) the age of a stratigraphic horizon, the thickness of eroded sediments at an unconformity, and the variation of paleoheat flux with time were determined simultaneously by thermal indicator inversion in a single well; (b) two neighboring wells, less than 10 km apart, provided essentially identical ages for the same formation when tested using the inversion procedure. The ability to determine stratigraphic horizon ages from inversion of thermal indicator data implies that sedimentation rates can be determined; thus, basinal evolution can be inferred to a degree of resolution not previously obtainable from assumed interpolation methods applied to determine the age of horizons between a limited set of stratigraphic horizons of known ages. 相似文献
466.
北京十三陵中元古界长城系沉积相标志及沉积环境演化模式 总被引:9,自引:6,他引:9
北京十三陵地区中元古界长城系包括5个组:常州沟组、串岭沟组、团山子组、大红峪组、高于庄组,前2个组主要由碎屑岩组成,后3个组主要由碳酸盐岩组成。众多的沉积相标志从不同侧面说明:常州沟组沉积属于滨浅海碎屑岩沉积环境;从串岭沟组开始,其沉积环境向碳酸盐岩沉积环境过渡;后3个组沉积时的环境为典型的陆表海碳酸盐岩沉积环境。在综合研究的基础上给出了沉积环境演化模式。另外,长城系还有许多特殊的沉积现象值得进一步研究和讨论:世界上最古老的宇宙球粒;高于庄组白云岩层面上双脊波痕的内碎屑颗粒成因和硅化白云岩内青鱼骨状层理及硅质团粒的成因;特别是在大红峪组首次发现太阳星云物质-碳质球粒陨石。 相似文献
467.
对研究区成矿物质来源、成矿物理化学条件、成矿地质条件以及找矿标志进行了研究和探讨。为该区的地质找矿提出了依据和方向。 相似文献
468.
469.
Arthur Conacher 《The Australian geographer》1998,29(2):175-189
Environmental or land quality indicators are being developed internationally as a means whereby the ‘State of the Environment’ (SoE) can be assessed and trends monitored. In Australia, the use of indicators in SoE reporting is in its early stages of development. Indicators have been developed, in relation to agriculture, for flora and fauna, soil, chemical contamination, surface waters and groundwater. Internationally, the World Bank has listed ‘indicators of pressure’ on the land, ‘indicators of state and impact’, and ‘indicators of response’ for each of seven major issues of land degradation. Late in 1996, an ‘indicators of catchment health’ workshop in Australia identified a relatively small number of key indicators relating to farm productivity, soil health, water quality and ‘landscape integrity’, later adding social indicators, and also distinguishing between indicators at farm and catchment scales. A broad range of other indicators was also considered by various participants in the workshop, which concluded by supporting a nationally co‐ordinated effort and the establishment of a national steering committee. Although most indicators are static measures, those from which predictions can be made require a greater emphasis on the functioning of the system. This implies that indicators are only one aspect of system modelling, and that environmental or land assessment needs to progress further than the search for quality indicators. Since this involves both biophysical and human processes, geographers should be playing a central role. 相似文献
470.
The present communication addresses the potential use of damage features, observed in the ancient ruins of the Avdat archeological
site (Negev Desert, Israel) as a tool to identify the seismic origin of the destruction there and roughly to determine the
direction of seismic wave propagation.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献