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471.
地质学家重视研究深部(变质)CO_2对古气候的影响 总被引:5,自引:0,他引:5
地质学家重视研究深部(变质)CO2对古气候的影响贾跃明(中国地质矿产信息研究院,北京,100037)近几年来,随着过去全球变化研究的兴起,地质学家越来越重视地质历史时期影响大气CO2浓度的因素的调查。不少人认为,变质作用和火山活动可能是过去大气中CO... 相似文献
472.
张晓云 《华北地质矿产杂志》1996,11(2):245-251
辛安泉是北方第二大泉,泉域面积13000km^2。根据环境水文地质条件,将拉域划分为四个子系统。采用饮用水卫生标准和污染起始值对系统内地下水水质进行评价,并对其污染成因进行了分析。 相似文献
473.
山西奇村地热田的勘察与研究 总被引:2,自引:0,他引:2
通过近期对山西省忻州市奇村地热田进行的实地物化探勘察发现:地下热水的分布范围内视电阻率普遍偏低,且水温愈高,视电阻率愈低,在α 卡异常处均有地下热水存在。该地热田的热水分布区内的隔水层和盖层为亚粘土,粘土层。基地下热水的水化学类型为氯化物硫酸钠型及氯化钠型,热田热水赋存和滞留于浅层次生热储内。 相似文献
474.
This paper deals with dissolved inorganic carbon (DIC) and organic carbon (DOC) in pore waters from a 150 m deep hole drilled through the carbonate barrier reef of Tahiti and its underlying basalt basement. Alkalinity-pH measurements were used to calculate the DIC species concentration, and DOC was analysed according to the high temperature catalytic oxidation technique. Salinity was used as a conservative tracer to help identify water origin and mixing within the hole. Water mixing, calcium carbonate dissolution and mineralization of organic carbon combined to form three distinct groups of pore water. In the deeper basalt layers, pore water with alkalinity of 1.4 meq kg–1 pH of 7.6 and p(CO2) of 1.2 mAtm was undersaturated with respect to both aragonite and calcite. In the intermediate carbonate layer, pore water with alkalinity of more than 2.0 meq kg–1, pH of 7.70 and p(CO2) of 1.4 mAtm was supersaturated with respect to both aragonite and calcite. The transition zone between those two groups extended between 80 and 100 m depth. The shift from aragonite undersaturation to supersaturation was mainly attributed to the mixing of undersaturated pore waters from the basalt basement with supersaturated pore waters from the overlaying limestone. In the top of the reef, inputs from a brackish water lens further increased p(CO2) up to 5.6 times the atmospheric P(CO2). 相似文献
475.
Franz May Stephan Hoernes Horst J. Neugebauer 《International Journal of Earth Sciences》1996,85(4):782-799
Three major, interdependent processes control the genesis and distribution of mineral and thermal waters in the Rhenish Massif,
Central Europe: (a) Magmatic processes in the upper mantle provide most of the CO2 to produce bicarbonate waters in shallow aquifers. (b) Extension of the brittle upper crust enables the ascent of sodium
chloride waters. (c) Uplift and erosion shape the massif's relief, which determines the extent of flow systems and the distribution
of thermal springs. The chemistry of mineral waters further depends on the aquifers' mineral composition. A comprehensive
set of hydrological, chemical, tectonic and geophysical data on the Rhenish Massif has been compiled. It was used to classify
the mineral waters and to map the spatial distribution of water properties. The composition of cuttings from several representative
wells producing different water types shows that the hydrothermal alteration of the aquifer rocks consists mainly of kaolinization
of chlorite and dissolution of feldspar. Numerical transport simulations favour two modes of groundwater flow: topography-driven
flow and the pressure-driven ascent of basement brines along active faults. Thermal convection is less important. 相似文献
476.
In order to determine time-dependent changes in estuarine pore-water chemistry and flux variations across the sediment-water interface, sediment cores of an intertidal mud flat in the Weser Estuary were taken monthly over a one-year period. Sediment temperature, pH, Eh, Cl–, O2, NO
3
–
, and SO
4
2–
pore-water concentrations were measured and showed variations that relate to the changes of surface temperature and estuarine water composition. Fick's first law was applied to quantify diffusive fluxes from concentration gradients in the diffusive boundary layer and in the pore water. Total nitrate fluxes were calculated from flux chamber experiments. Diffusive oxygen fluxes increased from 5 mmol m–2 d–1 in winter to 18 mmol m–2 d–1 in early summer, while nitrate fluxes into the sediment increased from 3 mmol m–2 d–1 in winter to 60 mmol m–2 d–1 in early summer. Oxygen and nitrate fluxes into the sediment correlated linearly to sediment temperature. Sulfate fluxes increased from 0.5 mmol m–2 d–1 in winter to 10 mmol m–2 d–1 in August and September. Converted into carbon fluxes, the sum of these oxidants ranged from 10 mmol m–2 d–1 in winter to 80 mmol m–2 d–1 in summer. An estimation of the upper limit of the annual nitrate flux into the sediment showed that about 10% of the 250,000 t of nitrate discharged annually by the river may be decomposed within the inner Weser Estuary. 相似文献
477.
青藏高原东北地区现代降水中δD与δ^18O的关系研究 总被引:11,自引:0,他引:11
根据对取自青藏高原东北地区部分降水样中氢氧稳定同位素比率的分析,得到沱沱河站的大气水线(MWL)为:δD=8.25δ^18O+9.22‰,与全球平均MWL的差别较小;德令哈、西宁站的MWL分别为:δD=5.86δ^18O-27.28‰和δD=6.96δ^18O-30.19‰,均与全球平均MWL差别较大。这主要归因于水汽源地的非平衡蒸发和凝结物在非饱和大气中降落时的非平衡蒸发。上述地区的过量氘Exd 相似文献
478.
系统研究了Ge-ARS-H2C2O4-V体系报道极谱催化波的影响因素,测定了Ge-ARS-H2C2O4三元配合物的配合比为1:2:1。实验初步证明了该体系催化波为具有吸附性质的平行催化波。本法检出限为0.14mg.mL^-1,相对标准偏差小于9.89%,标准回收率为93.70%-109.0%,0-50mg.mL^-1的锗具有良好的线性关系。 相似文献
479.
480.
本文从X射线的性质,以及X射线与物质作用的机理出发,对井液效应进行了研究,并对其影响过程进行模拟。在理想井液模型上,推导出X射线活度与钻孔参数的数理关系。在此基础上,进一步研究得到了能适应野外多变情况的井液效应校正公式(CBWE)和方法。 相似文献