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711.
712.
宁夏引黄灌区蒸散发量的计算模拟 总被引:1,自引:0,他引:1
为了解宁夏引用耗排黄河水量的问题,针对水域、裸地-植被域和不透水域等不同土地利用类型,采用了Penman公式、Noilhan-Planton模型和Penman-Monteith公式等对相应土地利用类型的蒸散发量进行计算模拟,从而确定了区域蒸散发量的计算模拟方法。依据计算模拟结果和试验观测数据对区域蒸散发量的计算模拟方法进行了验证。基于以上研究,以宁夏引黄灌区为例,对宁夏引黄灌区2000年的蒸散发量和1991-2000年间蒸散发量的变化趋势进行了计算模拟,并就降雨量对区域蒸散发量的影响关系进行了分析。模拟结果表明,2000年宁夏引黄灌区(不计黄河干流河道本身的蒸发)的总蒸散发量为4.59×109m3,计入黄河干流河道本身的蒸发则总蒸散发量为4.97×109m3;1991-2000年10年间区域总蒸散发量和区域农田蒸散发量呈增加趋势,天然林草灌木地和荒地蒸散发量呈下降趋势;区域总蒸散发量、农田蒸散发量、林草灌木地蒸散发量等与降雨量有着较好的相关关系,并随着降雨量的增加呈递增趋势。 相似文献
713.
Yuichi MORISHITA 《Resource Geology》1999,49(4):243-257
Abstract: Predominant Zn-rich ore bodies were found to a deep part of the Sakonishi area in the Kamioka mining district, Japan. The ore mineralization was recognized at 230 to 300m above sea level in the Sakonishi area. Since crystalline limestone is broadly distributed over the area, and the variation in isotopic composition is easily detected, the isotopic prospecting should be powerful in surveying of the extent of the ore bodies and the related hydrothermal system. Although isotopic anomalies have been extracted two-dimensionally so far, three-dimensional information is possibly more powerful. In this paper, Zn-rich ore bodies in the Sakonishi area are treated as hydrothermal ore deposits, and the importance of the activity of hydrothermal fluids during mineralization is emphasized. Oxygen and carbon isotopic ‘iso–surfaces’ are three-dimensionally calculated for the Sakonishi area. The δ18O values of crystalline limestone from the surface and from the drill holes range from +8. 1 to +21. 1% and from –2. 7 to +20. 4%, respectively. The δ13C values of crystalline limestone from the surface and from the drill holes range from –1. 0 to +5. 3% and from –7. 7 to +4. 6%, respectively. The oxygen and carbon iso-topic ratios at the mineralization level are extremely low, but there are exceptions as to carbon isotopes. The oxygen isotopic ratios of crystalline limestone may decrease by isotopic exchange reaction with a hydrothermal fluid, while the carbon isotopic ratios slightly change. Since the precipitated calcite from a hydrothermal fluid has low carbon isotopic ratio and various oxygen isotopic ratio depending on the formation temperature, the bulk sample of crystalline limestone containing the precipitated calcite has oxygen and carbon isotopic ratios of relatively low values accordingly. Thus the decrease mechanism for carbon isotopic ratio of crystalline limestone is different from that for oxygen isotopic ratio. Samples with the carbon isotopic ratio of –4 to –8% are considered to be crystallized from hydrothermal fluids. Since the oxygen and carbon isotopic ratios of crystalline limestone at the ore mineralization level are low, the ore bodies are considered to have formed by a prominent hydrothermal activity. Thus oxygen and carbon isotopic ratios of crystalline limestone can be used as an indicator of the related hydrothermal activity. The alteration such as chloritization is intense near fractures in the Sakonishi area, showing that the hydrothermal system is controlled by a fracture system. It is assumed that the decreased isotopic ratios indicate the high degree of reactivity with hydrothermal fluids, and the depleted zone in oxygen and carbon isotopes may correspond to the conduit of the hydrothermal fluids. 相似文献
714.
六盘水煤层气选区评价参数及勘探开发模式 总被引:4,自引:4,他引:0
本文通过对贵州六盘水地区煤层气地质特征的分析,借鉴国内外媒层气勘探开发的成功经验,提出符合贵州六盘水地区煤层气地质特征的煤层气选区评价参数,初步建立一套符合贵州六盘水地区煤层气地质特征的煤层气勘探开发模式。 相似文献
715.
716.
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718.
成都城市区域小气候时空变化特征分析 总被引:1,自引:0,他引:1
利用成都市12个自动站的气象资料,分析了成都市区域小气候及其变化特征.研究表明,成都城市热岛现象并非出现在城市中心区,而是北部和东部工业区,其平均气温相对较高,降水量偏多;南部文化区平均气温最低,风速最大;西部旅游居家区气温年变化最小,且有冬暖夏凉的特征,降水量偏少;城市中心区风速最小. 相似文献
719.
淄博市淄川区饮用天然矿泉水按照含水层性质可划分为松散岩类孔隙水、碳酸盐岩类裂隙岩溶水和岩浆岩类构造裂隙水3大类。区内29眼井泉监测点饮用天然矿泉水检测结果显示,研究区存在锶型、锂型和锶锂复合型3种类型矿泉水。从水岩作用角度分析了矿泉水中锶和锂的来源,认为研究区广泛分布寒武纪碳酸盐岩,石灰岩尤其是鲕状灰岩中丰富的锶元素,是锶矿泉水形成主要的物源条件之一;地下水沿灰岩裂隙岩溶运动为矿泉水的形成创造了重要的水动力条件;研究区腐殖质经低矿化近中性的大气降水淋滤后,形成富含腐殖酸的偏酸性溶液入渗地下,对地下岩层产生溶解、溶滤作用,随着溶解过程的进行,岩石中的锶元素大量进入地下水中。 相似文献
720.
In the northwestern margin of the Youjiang basin(NWYB)in SW China,many Carlin-like gold deposits are highly antimony(Sb)-rich,and many vein-type Sb deposits contain much Au.These deposits have similar ages,host rocks,ore-forming temperatures,ore-related alterations and ore mineral assemblages,but the Au and Sb metallogenic relations and their ore-forming process remain enigmatic.Here we investigate the large Qinglong Sb deposit in the NWYB,which has extensive sub-economic Au mineralization,and present a new metallogenic model based on in-situ trace elements(EPMA and LA-ICP-MS)and sulfur isotopes(NanoSIMS and fs-LA-MC-ICPMS)of the ore sulfides.At Qinglong,economic Sb ores contain coarse-grained stibnite,jasperoid quartz and fluorite,whilst the sub-economic Au–Sb ores comprise dominantly veined quartz,arsenian pyrite and fine-grained stibnite.Three generations of ore-related pyrite(Py1,Py2 and Py3)and two generations of stibnite(Stb1 and Stb2)are identified based on their texture,chemistry,and sulfur isotopes.The pre-ore Py1 is characterized by the lower ore element(Au,As,Sb,Cu and Ag)contents(mostly below the LA-ICP-MS detection limit)and Co/Ni ratios(average 0.31)than the ore-stage pyrites(Py2 and Py3),implying a sedimentary/diagenetic origin.The Py2 and Py3 have elevated ore element abundance(maximum As=6500 ppm,Au=22 ppm,Sb=6300 ppm,Cu=951 ppm,Ag=77 ppm)and Co/Ni ratios(average 1.84),and have positive As vs.Au–Sb–Cu–Ag correlations.Early-ore Stb1 has lower As(0.12–0.30 wt.%)than late-ore Stb2(0.91–1.20 wt.%).These features show that the progressive As enrichment in ore sulfides is accompanied by increasing Au,Sb,Cu and Ag with the hydrothermal evolution,thereby making As a good proxy for Au.As-rich,As-poor and As-free zones are identified via NanoSIMS mapping of the Au-bearing pyrite.The As-rich zones in the Qinglong Au-bearing pyrites(Py2 and Py3)and ore stibnites(Stb1 and Stb2)have narrowδ34SH2S ranges(-8.9‰to +4.1‰,average-3.1‰)and-2.9‰to +6.9‰,average + 1.3‰),respectively,indicating that the Au-rich and Sb-rich fluids may have had the same sulfur source.Published in-situ sulfur isotopic data of pyrite As-rich zones from other Carlin-like Au deposits(Shuiyindong,Taipingdong,Nayang,Getang and Lianhuashan)in the NWYB have similar ore-fluidδSH2S values(-4.5‰to +6.7‰,average-0.6‰)to those of Qinglong.Therefore,we infer that the sulfur of both Au and Sb mineralization was derived from the same magmatic-related source(0±5‰)in the NWYB.Moreover,the core of pyrites(Py1)has variable S isotope fractionation(-18.9‰to +18.1‰,mostly +3‰to +12‰),suggesting that the higher-34S H2S was produced by bacterial sulfate reduction(BSR).The hydrothermal pyrite(Py2 and Py3)δ34S values gradually decrease with increasing As concentrations,and ultimately,within the restricted range(-5‰to +5‰)in As-rich zones.This variation implies that the As-rich pyrite was formed through ongoing interactions of the magmatic-hydrothermal fluid with pre-existing sedimentary pyrites,causing the progressive decreasing δ34S values with As content increase,Hence,the fluid/mineral interaction may have generated the observed variation in δ34S and As contents.Overall,comparing the Au and Sb deposits in the NWYB,we favor a magmatic-related source for the Au–Sb–As-rich fluids,but the Au-and Sb-ore fluids were likely evolved at separate stages in the ore-forming system. 相似文献