Chemical weathering in the Upper Huang He (Yellow River) draining the eastern Qinghai-Tibet Plateau

We examined the fluvial geochemistry of the Huang He (Yellow River) in its headwaters to determine natural chemical weathering rates on the northeastern Qinghai-Tibet Plateau, where anthropogenic impact is considered small. Qualitative treatment of the major element composition demonstrates the dominance of carbonate and evaporite dissolution. Most samples are supersaturated with respect to calcite, dolomite, and atmospheric CO₂ with moderate (0.710-0.715) ⁸⁷Sr/⁸⁶Sr ratios, while six out of 21 total samples have especially high concentrations of Na, Ca, Mg, Cl, and SO₄ from weathering of evaporites. We used inversion model calculations to apportion the total dissolved cations to rain-, evaporite-, carbonate-, and silicate-origin. The samples are either carbonate- or evaporite-dominated, but the relative contributions of the four sources vary widely among samples. Net CO₂ consumption rates by silicate weathering (6-120 × 10³ mol/km²/yr) are low and have a relative uncertainty of ∼40%. We extended the inversion model calculation to literature data for rivers draining orogenic zones worldwide. The Ganges-Brahmaputra draining the Himalayan front has higher CO₂ consumption rates (110-570 × 10³ mol/km²/yr) and more radiogenic ⁸⁷Sr/⁸⁶Sr (0.715-1.24) than the Upper Huang He, but the rivers at higher latitudes are similar to or lower than the Upper Huang He in CO₂ uptake by silicate weathering. In these orogenic zones, silicate weathering rates are only weakly coupled with temperature and become independent of runoff above ∼800 mm/yr.     

Determining the optimal pumping duration of transient pumping tests for estimating hydraulic properties of leaky aquifers using global curve-fitting method: a simulation approach

Global curve-fitting method (GCFM) is regarded as an effective approach in hydrogeological parameter estimation, as it integrates and uses pumping data and water recovery data of a transient pumping test for parameter estimation. The impacts of pumping duration on hydrogeological parameter estimation by GCFM were investigated in the present study using 2 in situ pumping tests and 24 simulated transient pumping tests. Empirical formulas for determining the optimal pumping duration were derived. The study results suggest that pumping duration will have impacts on the accuracy of hydrogeological parameter estimation. When pumping duration is longer than a certain period, relative errors of hydrogeological parameter estimation keep relatively stable within an acceptable limit. Therefore, it is unnecessary to continue the pumping for a very long time after the groundwater level has become stable. When the change rate of drawdown over time (γ) in an observation well located within a distance of 100 m to the pumping well reaches 0.134, the pumping can be stopped. If there are more than one observation wells in a pumping test, the smallest γ value should be selected to determine the optimal pumping duration. This research is meaningful in the instruction of pumping tests, and will reduce test costs greatly.     

三维构造模拟方法--体平衡技术研究

为了实现三维构造史模拟,在二维平衡剖面技术的基础上,提出了适用于在维构造模拟的方法－体平衡技术,其核心是通过分析断层演化及地层变形在三维空间中的特殊性,建立三维复杂构造的数学模型和三维物质平衡方法,它简化了平衡时三维的体积计算和对不平衡体积构造体的适应性,从而减少了三维构造模拟的实现难度。     

浙江省千岛湖西部地区旅游资源功能分类及开发建议

以１∶５万区域地质调查资料为基础，详细论述了千岛湖西部旅游资源的特点，据其功能划分为水文景观、生物景观、地学景观、地史遗迹、休闲渡假、人文景观和土特产品７大类，并对不同类型的旅游资源提出了开发建议     

黑龙江省砂金的成色特征

对黑龙江省８４个砂金样品的成色进行测定了并与７个岩金样品对比，结果表明，砂金成色变化较大，与原生岩金来源有明显继承性关系，由于受后生风化作用影响，砂金普遍具有金壳结构。砂金成色与其粒度及在河谷中产出位置呈规律性变化，由成色计算出来的溶蚀系数，可作为指导寻找原生金矿的依据之一。     

A preliminary stable isotope study on Mogok Ruby, Myanmar

The primary occurrence of ruby in the Mogok area, northern Myanmar is exclusively found in marble along with spinel–forsterite-bearing marble and phlogopite–graphite marble. These marble units are enclosed within banded biotite–garnet–sillimanite–oligoclase gneisses. Samples of these marbles collected for C–O stable isotope analysis show two trends of δ¹³C–δ¹⁸O variation resulting most likely from fluid–rock interactions. Ruby-bearing marble and phlogopite–graphite marble follow a trend with coupled C–O depletion, whereas spinel–forsterite-bearing marble follows a δ¹⁸O depletion trend with relatively constant δ¹³C values. Ruby formation might have resulted from CO₂-rich fluid–rock interaction, while spinel–forsterite-bearing marble was genetically related to CO₂-poor fluid–rock interaction. Both fluids may have arisen from external sources. Based on graphite Raman spectral thermometry, the estimated temperature for phlogopite–graphite marble, and probably ruby-bearing marble, was lower than 607 °C, and for spinel–forsterite-bearing marble, lower than 710 °C. Contrasting C/O diffusion between graphite/ruby/spinel/forsterite and calcite, local variations of isotopic compositions of newly formed minerals as a result of non-pervasive fluid infiltration, and open-system isotopic disturbance during cooling may have affected C-/O-isotopic fractionations between minerals. The estimated high formation temperatures for ruby and spinel/forsterite imply that the parental fluids may have been related to nearby igneous intrusions and/or metamorphic processes. Whether these two types of fluid were genetically related is unclear based on the present data.     

泰宁县地质灾害影响因素及防治建议

在泰宁县地质灾害详细调查的基础上,统计分析了地质灾害发生与地形（地貌）、地层岩性、降雨、人类工程活动等影响因素的关系。地质灾害主要分布于丘陵、低山的缓坡一陡坡地带,尤其是变质岩、侵入岩地区;降雨和人类工程活动是主要的外在诱发因素。     

Studies on Fast Loading Technique of Soft Rock and Automatic Data Processing

A fast loading technique of soft rocks and an automatic data processing system used in the experiments are presented in this paper. Research results demonstrate that the 10t fast loading equipment is applicable to study on dynamic mechanical properties of soft rocks under medium strain rate. By using an automatic data processing system, a group of curve which reflect the relations between some physical parameters, such as σ-ε and σ-t，can be drawn by a plotter, so that the period of experiment can be reduced, and more accurate results can be expected.