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111.
铷、铯是我国战略性关键矿产资源。西藏盐湖卤水中赋存着丰富的铷、铯资源,但是品位普遍低于10 mg/L。根据热泉与盐湖锂、铷、铯等元素的补给关系和含量差异特征及铷、铯极易被黏土矿物吸附等特点,推测盐湖沉积物中赋存一定规模的铷、铯资源。为验证该推测,本文选取西藏拉果错、聂尔错、依布茶卡、当穹错、扎布耶茶卡等5个典型盐湖,采集卤水和沉积物样品各5件,开展水体中铷、铯含量和沉积物矿物成分分析,结合沉积物分相淋滤实验,得出如下结论:西藏拉果错、当穹错、聂尔错盐湖卤水铷、铯含量和资源量与其补给量差异显著,大量的铷、铯资源消耗于盐湖沉积物中;盐湖沉积物中的铷、铯含量远高于卤水。铷、铯在沉积物水溶相、碳酸盐相中含量较低,主要以吸附形式赋存于黏土矿物(主要为伊利石),吸附点位包括基面位置、难解吸的磨损边缘及层间位置。盐湖沉积物铷、铯资源量远超大型矿床规模,黏土矿物中铷、铯含量高达100 n×10-6,超过固体盐类矿产综合评价指标,相较于现有盐湖钾产品中的铷资源、含铯硅华中的铯资源开发,具有较好的开发利用性,是一种潜在的铷、铯资源。本研究成果有助于完善盐湖铷、铯富集成矿机制,并为高效开发盐湖中的铷、铯资源提供理论支撑。  相似文献   
112.
Australia has numerous landforms and features, some unique, that provide a useful reference for interpreting the results of spacecraft orbiting Mars and exploring the martian surface. Examples of desert landforms, impact structures, relief inversion, long-term landscape evolution and hydrothermal systems that are relevant to Mars are outlined and the relevant literature reviewed. The Mars analogue value of Australia's acid lakes, hypersaline embayments and mound spring complexes is highlighted along with the Pilbara region, where the oldest convincing evidence of life guides exploration for early life on Mars. The distinctive characteristics of the Arkaroola Mars Analogue Region are also assessed and opportunities for future work in Australia are outlined.  相似文献   
113.
A preliminary scuba survey of oligotrophic Lake Rotoma in 1972 revealed a vegetation mainly composed of native hydrophytes in which exotics were at an early stage of colonisation. In 1973 the presence of species was recorded in 5708 quadrats (625 cm2) at 1 m intervals along a total of 50 line transects placed systematically around the lake. Water depth was measured, and quadrat cover and substrate type were subjectively estimated. Species frequency calculations showed that the dominant vegetation pattern was a characean meadow of Chara fibrosa f. acanthopitys (A.Br.) R.D.W., Nitella leptostachys var. leonhardii (R.D.W.) R.D.W., and N. pseudoflabellata var. mucosa (Nordst.) Bailey. The charophytes extended over a depth range of 1–17.5 m on a wide variety of substrates and gradients. Native vascular plants were absent from many transects, and had a depth range only from 0 to 4.5 m, with most occurring above 3.5 m. The Low Mixed Community, found in shallow water less than 1.25 m in depth at the northeast end of the lake, provided this area with a high species diversity. Exotic hydrophytes had established in many areas around the lake. The distribution of Lagarosiphon major (Ridley) Moss and Elodea canadensis Michx. appeared to coincide with boating access and fallen submerged trees over a depth range of 0–6.0 m, although much of the available habitat had not yet been exploited. Emergent species were most abundant within the southwest inlet and also in the lagoons surrounding the lake where sheltered conditions and shallow gradients prevail.  相似文献   
114.
The distributions of two swimming crabs endemic to the New Zealand region are described, mostly from material obtained at 118 of 2544 New Zealand Oceanographic Institute benthic stations sampled.

Nectocarcinus antarcticus (Jacquinot) was found within the geographic limits 34°S‐51°S and 166° E‐176° W, with concentrations around Cook Strait, the Chatham Rise, Foveaux Strait, and the Auckland Is. N. bennetti (Takeda & Miyake) occurred between 44° S and 53° S, and 165° E and 180°, most frequently in the south and west, on the ‘highs’ of the Campbell Plateau. Although the distributions overlap between 44° S and 51° S, and this overlap zone produced most of the available material, only one joint occurrence of the two species was noted. This apparent separation was not satisfactorily explained by any of the ecological factors recorded. The depth ranges of both species were broadly similar (0–550 m for TV. antarcticus, 20–474 m for JV. bennetti); both were most frequently obtained at depths less than 200 m. Both occurred primarily on the coarser sediment grades, though N. antarcticus occupied a broader range of grades than N. bennetti.

The size ranges of the two species were similar; carapace lengths were 8.0–62.0 mm for N. antarcticus and 5.8–68.0 mm for N. bennetti. The larger specimens of both species were found towards the southern limits of distribution. Larger specimens of N. antarcticus were absent from depths greater than 120 m; smaller N. antarcticus and all N. bennetti occurred throughout their respective depth ranges. Ovigerous N. antarcticus (smallest, 8.8 mm carapace length) were obtained at depths of 17–263 m from May to October; ovigerous N. bennetti (smallest 36.1 mm) were from depths of 150–183 m in May only.  相似文献   
115.
汤磊  熊健 《矿产与地质》2010,24(5):475-480
为解决干旱高山区的深部找矿问题和探索地电化学法在干旱高山区寻找隐伏铜镍矿产的可行性,在青海化隆拉水峡铜镍矿区开展了地电提取测量法、土壤离子电导率测量法寻找隐伏铜镍矿的试验研究,通过对已知矿体的地电化学法找矿试验,在隐伏铜镍矿体上测出了清晰的地电化学异常。对矿区的深部及外围的找矿预测中,在A区发现3个地电化学Ni、Cu及电导率异常,在B区发现3个地电化学Cu异常、1个Ni异常、3个电导率异常,在C区发现了3个地电化学Cu异常、2个地球化学Ni异常、3个电导率异常,推测在上述地电化学异常区内寻找隐伏铜镍矿会有新的突破。  相似文献   
116.
我国盐湖钾盐资源现状及提钾工艺技术进展   总被引:6,自引:3,他引:3  
中国是一个农业大国, 钾肥缺口很大。中国又是一个多盐湖的国家, 盐湖中蕴藏着丰富的钾盐资源, 有望解决中国的缺钾问题。中国已经建立了青海察尔汗和新疆罗布泊两个钾肥生产基地, 但还是远远满足不了国内钾肥需求, 70%需要依赖进口。因此, 有必要继续加强钾盐开发研究, 建立新的钾肥生产基地。通过长期攻关, 我国氯化物型和硫酸盐型盐湖形成了比较成熟的提钾工艺路线, 但是, 碳酸盐型盐湖提钾研究刚刚起步。本文对青海察尔汗盐湖和新疆罗布泊盐湖两大中国钾肥生产基地的资源及生产工艺进行了分析研究, 其成功的开发经验可用来指导我国同类型其他盐湖钾资源的开发; 探讨了开发我国碳酸盐型盐湖钾盐的可行之路, 碳酸盐型盐湖通过技术创新, 可以在盐湖现场获得钾肥产品; 指出我国不同水化学类型的盐湖应采取不同的资源利用工艺路线。  相似文献   
117.
对青藏高原高寒草甸30%、60%和93%三种覆盖度下,多年冻土活动层的土壤水分随季节变化的观测研究,结果表明:多年冻土活动层土壤水分分布对植被覆盖变化响应强烈.年内不同时期,植被覆盖度为65%和30%的土壤表层20cm深度内水分含量及分布相似,每次降水后30%覆盖度土壤水分的变率略大于65%覆盖度的;而93%覆盖度土壤水分在年内解冻开始到冻结前均小于前两种覆盖类型;植被覆盖度越小,土壤冻结和融化响应时间越早,响应历时也越短;浅层土壤冻结和融化对植被覆盖度的响应程度较强,接近深层土壤冻结和融化对植被覆盖度的响应程度降低.覆盖度为30%和65%土壤水分在整个冻结过程的减少幅度比93%覆盖度土壤大10%~26%,而融化期水分增加幅度更大为1.5%~80%;土壤冻融的相变水量对植被覆盖度变化响应明显,植被覆盖度降低,土壤冻结和融化相变水量增大.由于受植被蒸腾与地表蒸散发和土壤温度梯度的影响,融化期土壤剖面的水分重新分配,总体上呈现水分向剖面上部和底部迁移,剖面中部60~80cm深度左右的土壤出现"干层".  相似文献   
118.
通过对腾格里沙漠地区遥感影像信息分析与野外实地调查,圈定出大小盐湖122个,查明了盐湖的空间分布规律,划分了图兰泰湖-头道湖、白碱湖-西硝池、苏武山湖-汤家海、鸡龙同古-和屯、通古楼诺尔-巴彦达来五个盐湖分布区,对各分布区盐湖的成因类型、沉积特征、成矿规律及资源状况进行了研究,为进一步勘查、开发和利用本区资源提供了依据。  相似文献   
119.
This study focuses on two Mediterranean oligotrophic high mountain lakes located in the Sierra Nevada National Park (southern Spain): Río Seco (RS) and La Caldera (LC). A combination of field measurements and laboratory experiments is used: (i) to quantify in situ settling fluxes; (ii) to study the soluble reactive phosphorus (SRP) release or uptake by settling and resuspended particles; and (iii) to discriminate between the biotic and abiotic contribution for such patterns. In general, all suspensions (lake water untreated and lake water enriched with settling and with resuspended matter) in both study lakes release significantly more SRP to the solution when biological activity was suppressed. Biological uptake from settling and resuspended matter is likely to be limited by the bacterial consumption of P. Despite of these similarities, this study has revealed notable differences in the effect of sediment resuspension on SRP dynamics in both study lakes, when simulating natural conditions (biotic and abiotic processes). While in LC, the enrichment of lake water with settling and with resuspended matter did not cause an increase in SRP concentrations in lake water, SRP concentrations in RS at the end of the experiment were significantly higher (probability P < 0.05) in lake water enriched with resuspended matter (3.2 μg/l) than in natural lake water (lower than the detection limit). Accordingly, it is reasonable to expect that sediment resuspension, which occurs more frequently in RS compared with LC, affects drastically the SRP availability in the water column in RS.  相似文献   
120.
Temporal trends in water clarity and land-use/land-cover (LULC), as well as the relationship between changes in water clarity and LULC, were analyzed using water clarity values extracted from Landsat images from 1986 to 2008, acquired for east-central Maine. Of 40 lakes identified using satellite imagery, our analysis found one lake with a significant decrease in water clarity. In a second data-set, with 99 lakes, we identified two lakes with a significant increase in water clarity. Analyses of the relationship between temporal changes in the water clarity and LULC did not identify any clear, consistent, relationships between changes in the water quality variables and LULC. Overall, the results of this study aid in the identification of the relationship between water clarity and LULC, and identify temporal changes in water clarity. The findings of this study support the previous research that demonstrates the ability of satellite imagery to be used in assessments of water clarity, thus enabling evaluation at broader spatial scales and longer temporal scales than assessments that rely solely on ground-based data.  相似文献   
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