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1.
The Jifei hot spring emerges in the form of a spring group in the Tibet–Yunnan geothermal zone, southwest of Yunnan Province, China. The temperatures of spring waters range from 35 to 81°C and are mainly of HCO3–Na·Ca type. The total discharge of the hot spring is about 10 L/s. The spring is characterized by its huge travertine terrace with an area of about 4,000 m2 and as many as 18 travertine cones of different sizes. The tallest travertine cone is as high as 7.1 m. The travertine formation and evolution can be divided into three periods: travertine terrace deposition period, travertine cone formation period and death period. The hydrochemical characteristics of the Jifei hot spring was analyzed and compared with a local non-travertine hot spring and six other famous travertine springs. The results indicate that the necessary hydrochemical conditions of travertine and travertine cones deposition in the Jifei area are (1) high concentration of HCO3 − and CO2; (2) about 52.9% deep source CO2 with significantly high value; (3) very high milliequivalent percentage of HCO3 − (97.4%) with not very high milliequivalent percentage of Ca2+ (24.4%); and (4) a large saturation index of calcite and aragonite of the hot water.  相似文献   

2.
本文通过调查黄龙风景区水体的环境地质特征与微生物群落结构及多样性,并与黄石公园对比分析,探讨了两种特殊地理环境下的微生物群落结构和多样性及其对钙华沉积的影响。结果表明:黄龙沟泉水属于地下冷泉,且景区内覆盖着大量植被,水体中有大量藻类和细菌;黄石公园猛犸象温泉区泉水属于地下热泉,植被覆盖率很低,泉水中微生物多为嗜热菌,藻类较少。黄龙与黄石钙华主要由方解石组成并且微生物参与了钙华的形成过程。微生物对钙华沉积的作用,主要分为模板作用、产物诱导作用和代谢调控作用,对比探讨了特殊地质环境下的微生物对钙华沉积的贡献,指出微生物沉积作用在钙华沉积过程中的重要性,可为黄龙钙华“黑化”防治提供理论依据。   相似文献   

3.
In the periods 1980–1986 and 1990–2007 many boreholes were sunk during hydrogeological investigations in the center of the Karlovy Vary (Carlsbad) hot spring system. The extent and the depths reached were the greatest in the history of the geological investigation of the discharge area of the thermal system. The results of the drilling program enabled a detailed study of the rocks, groundwater and spring sedimentation in the area as well as the preparation of new proposals for changes in the spring-protection zones. The spring sedimentation consists of world-renowned hot spring travertine, with a wide range of morphological varieties of different origins and of different ages. The oldest U-series age data (230 ± 14 ka BP) have been obtained for travertine relicts located 22 m above the present-day bottom of the narrow valley of the Teplá River. Five other travertine deposits, partly overlapping in space and time were identified on the bottom and slopes of the valley. They were formed by gradual growth, by river erosion and since the fourteenth century by human activities.  相似文献   

4.
【研究目的】陆地热泉钙华作为火山、地热区常见的陆相碳酸盐岩沉积物/岩被广泛用于恢复古环境,但其中可反映古气候信息的代用指标多受复杂外界条件变化控制,因此利用热泉钙华进行古气候信息提取有待深入研究。【研究方法】本文对当前热泉钙华在重建古气候信息方面的成功案例进行了总结,并梳理了与热泉钙华沉积相关的各类气候、非气候影响因素。【研究结果】研究认为针对热泉钙华进行古气候恢复代用指标的选取,目前较为可行的有C-O同位素、主微量元素,孢粉学数据由于孢粉保存的局限性,可作为佐证信息,配合其他气候代用指标来检验古气候意义的正确与否,同时需将热泉钙华中各项气候代用指标与生物地层学、冰芯、石笋等相对成熟的古气候研究手段进行对比,使各类古气候替代指标相互验证,从而更好的解读热泉钙华中古气候信息。【结论】利用热泉钙华中的各项气候代用指标进行可靠的古气候信息提取与恢复具有可行性。创新点：本文梳理了国内外热泉钙华恢复古气候的成功案例,并探讨了针对热泉钙华进行古气候恢复研究存在的问题。  相似文献   

5.
Death Valley located in the Zagros Mountains, Khuzestan Province, Iran, along the Bangeston Fault line is a unique landscape. Water flows from a hot headstream through a colorful bed into the valley for about 2 km down-run and disappears through the alluvial deposits. This spring and its surrounding area were found to be deadly for both animals and humans. In the last decade, it has been reported that five persons and many animals have died. The reason for the toxicity of this water has not yet been specified. Attempts have been made to find out the secret behind death. The purpose of this paper is to study the Death Valley, which is located in the south of Iran (Tashan), as well as the lethal agent and other index mineral compounds in its water. Air analysis was performed near the headstream to find more about the fatal gas in the area. The results showed that the concentration of hydrogen sulfide was as high as 400 ppm near the spring during hot season, which could lead to pulmonary edema and death. Water in the area contains a high concentration of sulfide (1780 mg/L), which is a characteristic of thermal or hot spring waters. This gas is available along the stream and also far from the spring. The amount of spring water is high enough to be exploited for remedial purposes.  相似文献   

6.
The isotopic composition of calcite from travertine deposits of the Tokhana-Verkhnii hot spring in the Elbrus area shows broad variations in δ13C and δ18O (from +3.8 to +16.3‰ and from +24.6 to +28.1‰, respectively). The δ13C and δ18O values increase toward the sole of the travertine dome. The isotopically heaviest carbonates (δ13C of up to +16.3‰) were found near the bottom of the dome and composed ancient travertine, which are now not washed by mineral water. The scatter of the δ13C values of the fresh sample is slightly narrower: from +3.8 to +10‰. Calculations indicate that all carbonates of the Tokhana dome were not in equilibrium with spontaneous carbon dioxide released by the spring (\(\delta ^{13} C_{CO_2 } \) = ?8‰). To explain the generation of isotopically heavy travertine, a physicochemical model was developed for precipitation of Ca carbonates during the gradual degassing of the mineral water. The character of variations in the calculated δ13C values (from +5.5 to +13‰) is in good agreement with the tendency in the variations of the δ13C in the carbonate samples. The calculated and measured pH values are also consistent. Our results demonstrate that the isotopic composition of large travertine masses can be heterogeneous, and this should be taken into account during paleoclimatic and paleohydrogeological reconstruction.  相似文献   

7.
The recent discoveries of deeply buried Cretaceous reservoir bodies in the Atlantic Ocean revealed that relationships between the distribution of spring carbonate deposits and faults are poorly understood. The well‐exposed Quaternary deposits at Obruktepe (Denizli Basin, Turkey) provide an opportunity to reconstruct the three‐dimensional sedimentary architecture of such a system. Integration of sedimentological, lithofacies and geochemical analyses reveals complexity in the lateral relationships between sedimentary environments, faults and geothermal spring carbonates. Five environmental systems are distinguished based on the lithofacies analysis: (i) vent; (ii) smooth slope; (iii) travertine‐terrace; (iv) tufa‐barrage; and (v) flood systems. Encrusting, baffling and settling sedimentary processes are reflected in data acquired at several scales, from lithofacies observations to the morphology and arrangement of geobodies, together with microfabrics and stable carbon and oxygen isotope data. Mean values of +4·9‰ δ13C and −8·74‰ δ18O Vienna PeeDee Belemnite reflect geothermal circulation of springwaters. The environmental distribution and lithofacies indicate a lateral continuum between travertine and tufa deposits within this hot spring system. This finding supports two depositional models in which water flow variation is the main control on both CaCO3 precipitation and the resulting formation of travertine and tufa. The proposed models address the factors responsible for the development of these complex mound‐shaped carbonate spring deposits, and how they are related to fluid circulation at depth and in association with faults.  相似文献   

8.
世界自然遗产-四川黄龙钙华景观的形成与演化   总被引：15，自引：4，他引：11  
本文对作者十余年来在四川黄龙(世界遗产地)的钙华研究成果和最新的一些监测发现进行了综述, 目的是为公众更好地了解黄龙、保护黄龙提供科学基础。主要结果和结论是: (1)黄龙钙华的形成是由于地球深部高分压的CO2在碳酸盐岩补给区产生富含碳酸氢钙的地下水, 当其以泉的形式出露地表时, 由于泉水的CO2分压远远高于空气, 泉水中的CO2大量逸出, 结果导致碳酸钙过饱和而发生沉积; (2)黄龙钙华的颜色以黄色为主色调, 主要是在雨季因雨水冲刷土壤向水中混入泥沙的缘故; 而在旱季, 钙华主要形成于清亮干净的泉水, 因此, 钙华的颜色呈现出纯净碳酸钙沉积的本色-白色。这也是黄龙洞钙华剖面年层中出现黄-白相间亚层的原因; (3)高精度的铀-钍同位素测年表明, 黄龙钙华主体是全新世以来形成的; (4)地表水向地下河的漏失是黄龙地表水日益减少, 导致钙华体表面干涸, 从而气生蓝藻大量滋生, 致使某些钙华变黑的主要原因, 因此, 有必要尽早采取防渗补水措施; (5)旅游活动已对黄龙钙华景观产生影响, 包括上游人为践踏使下游钙华池淤塞, 以及磷酸盐污染使硅藻等过度繁殖和钙华沉积速率可能降低等, 因此, 必须尽早采取相应防控措施。  相似文献   

9.
S?cak Çermik (Sivas) is an important geothermal and recent travertine formation area in Central Anatolia. The majority of travertines found in the region comprise fissure-ridge type travertines according to morphological classification. At the location called Tepe Çermik within the travertine area, fill containing fossil bone fragments of Equus sp., Bovidae and other abundant animals formed within the fracture axis of a N–S striking fissure-ridge travertine developed under control of tectonic forces. The finds of these fossils in fissure-ridge travertines linked to tectonic forces indicates formation of a unique fossil environment created under the control of these forces. The Accelerator Mass Spectrometry Radiocarbon Dating analyses of fossils from the study area determined the fills were older than 43,000 years. The U/Th age of a sample from the most recently-formed banded travertine in the axis of the fracture was identified as 278,540 ± 18,436 years. As a result, the ages of fossils found within this fill are thought to be between 43,000 and 278,540 ± 18,436 years old. The high amount of perissodactyla and artiodactyla fossils found within fill in the axis of the fissure-ridge travertine probably indicates the presence of hominids who chose the region for hunting or settlement. The Equus sp. and Bovidae fossil samples found in the axis of the fracture indicate that in the dry and cold glacial period the paleogeography in a large portion of Anatolia comprised desert-like steppe.  相似文献   

10.
The purpose of this study is to determine the hydrological properties, groundwater potential, and water quality of the Çürüksu basin, western Turkey, and to contribute to the efforts of providing an adequate water supply for the city of Denizli. To achieve these objectives, the study consisted of mapping the geology and hydrogeology, determining the water balance, and defining the water quality. The basement rock units in the study area include several impervious metamorphic rock types and Mesozoic karstic limestone, which are overlain by Oligocene fluvial and lacustrine strata, Pliocene travertine and limestone, and Quaternary alluvium. The karstic limestone and the travertine and limestone strata constitute potential aquifers in the Çürüksu basin. The discharge regimes of the 22 springs in the two basins show little change through the year. The flow systems of the springs also have a large storage capacity and drainage occurs very slowly. The discharge of the springs does not appear to be affected immediately by monthly variations in precipitation. According to the water balance, the precipitation in the Çürüksu basin cannot provide all of the measured surface runoff. Excess runoff is 2?m3?s–1 in the Çürüksu basin, and in the adjacent Gökp?nar basin the deficit in surface runoff is also 2?m3?s–1. Thus, the underground catchment area of the springs extends beyond the surface drainage area of the Çürüksu basin. Although the P?narba??, Kazanp?nar, and Böceli springs emerge from the karstic limestone aquifer in the Çürüksu basin, these springs are fed from the adjacent Gökp?nar basin. The spring waters emerging from karstic limestone are fresh, of the calcium bicarbonate type, soft, and potable. The spring waters emerging from the travertine and limestone aquifer are low-temperature, brackish, of the calcium sulfate type, very hard, and not potable but useful for the irrigation. The occurrences of coal strata and hydrothermal activity have caused some deterioration of groundwater quality.  相似文献   

11.
为了对深变质岩区地热流体的成因和演化进行深入研究,在滇西陇川盆地开展了地质、放射性测量、磁法测量、水文地质和水文地球化学等调查工作,深入分析了盆地内尺巴处温泉的水文地球化学及同位素特征。结果表明：温泉水化学类型为HCO3·SO4·CO3-Na型,温泉中Li+质量浓度为0.220 mg/L,达到了锂矿泉水的命名标准,F-质量浓度为8.29 mg/L,可称为氟水,具医疗价值;温泉热水中冷水混入比例为0.72,热水补给高程为1 166.83 m,补给区温度为9.96℃,热储温度为191.71℃,循环深度为2 082.29 m,温泉天然放热量为9.49×1012 J/a;温泉水来源于大气降水,为深循环上升泉;地下水水化学组分的成因类型为岩石风化型,其主要组分来源于水岩相互作用;热源主要为深部未冷却的岩浆传导热及活动断裂产生的构造热,其次有少部分岩体中放射性同位素产生的放射热;深变质岩区温泉水中的pH值,SO42-、Cl-、Na+、SiO2质量浓度及总碱度高于冷水泉,Ca2+、Mg2+质量浓度低于冷水泉。  相似文献   

12.
Li Guo  & Robert Riding 《Sedimentology》1999,46(6):1145-1158
Holocene hot water travertine continues to form at Terme San Giovanni, near Rapolano Terme, central Italy, although artificial diversion of the water has reduced deposition. Mesothermal water (≈38–39 °C) emerging from fault-controlled vents located on a hilltop has created a linear fissure ridge 240 m long and up to 10 m high. Active parts of the ridge crest are covered by small cones; inactive parts are locally neotectonically fissured and have small pools. Ridge deposits include crystalline crust, paper-thin raft and shrub lithotypes. The ridge has both smooth and terraced marginal slopes, dominated by crystalline crusts with small shrubs in terrace pools. At the base of the ridge, there is a rapid transition to lateral flats and depressions, where water from the ridge collects and deposits shrub, irregular pisoid, reed, paper-thin raft and fine-grained and organic-rich travertines. Water channelled to nearby valley sides deposits thick crystalline crusts on valley slopes and waterfall overhangs, locally with small pools filled by smooth spherical pisoids. On the valley floor, mixing of waters forms varied stream-fill deposits that include micritic reed, paper-thin raft and coated bubble travertines. The diversity of travertine facies observed results from the location of the Terme San Giovanni hot springs on a hill crest, thus providing a wide array of downslope locations for further deposition. The abrupt facies transitions observed are characteristic of hot spring carbonates and result from a combination of rapid decrease in precipitation away from vents, variations in local surface topography and the feedback effect of travertine deposition itself, which dams and diverts water flow.  相似文献   

13.
象牙泉地处青藏高原高寒地区,因其钙华沉积酷似“象牙”而闻名。开展象牙泉形成机理的研究,有助于钙华景观的地质环境保护,对雅鲁藏布江构造带古环境演化、新构造活动的研究具有重要意义。文章以象牙源泉及其钙华沉积为研究对象,通过钙华成分、泉水水化学组分、氢氧同位素及相关性分析,探讨了象牙泉及钙华景观的形成机制,估算了钙华形成年代,讨论了钙华景观演化趋势。结果表明:象牙泉出露高程3 208 m,温度16.1 ℃,pH值6.06～6.64,溶解性总固体1 521.1～1 524.2 mg/L,为中偏弱酸性微咸水;阳离子以钠和钙为主,阴离子以碳酸氢根和氯离子为主,水化学类型为重碳酸钙型水;象牙泉具有较高的氯、钠及稍高的溶解性总固体特征,其氢氧同位素分布于全球大气降水方程线附近,说明象牙泉主要为大气降水补给,具有较长的径流途径和缓慢的循环速度,水岩作用强烈。象牙泉为溶解沉淀型,其化学组分来源于水岩相互作用过程碳酸盐岩矿物、硅酸盐岩矿物的溶解。象牙泉钙华沉积的化学成分主要为碳酸钙,占63.07%;次要成分为二氧化硅,占10.19%;属钙华为主、硅华次之的常温泉类钙华。钙均衡估算表明,象牙泉钙华形成于1.38万年前,其沉积速率约为0.27 mm/a。  相似文献   

14.
Calcite dendrite crystals are important but poorly understood components of calcite travertine that forms around many hot springs. The Lýsuhóll hot-spring deposits, located in western Iceland, are formed primarily of siliceous sinters that were precipitated around numerous springs that are now inactive. Calcite travertine formed around the vent and on the discharge apron of one of the springs at the northern edge of the area. The travertine is formed largely of two types (I and II) of complex calcite dendrite crystals, up to 1 cm high, that grew through the gradual addition of trilete sub-crystals. The morphology of the dendrite crystals was controlled by flow direction and the competition for growth space with neighbouring crystals. Densely crowded dendrites with limited branching characterize the rimstone dams whereas widely spaced dendrites with open branching are found in the pools. Many dendrite bushes in the pools nucleated around plant stems. Growth of the dendrite crystals was seasonal and incremental. Calcite precipitation was driven by rapid CO2 degassing of CO2-rich spring waters during the spring and summer. During winter, when snow covered the ground and temperatures were low, opal-A precipitated on the exposed surfaces of the dendrites. Segmentation of dendrite branches by discontinuities coated with opal-A and overgrowth development around sub-crystals resulted from this seasonal growth cycle. The calcite dendrite crystals in the Lýsuhóll travertine differ in morphology from those at other hot springs, such as those at Lake Bogoria, Kenya, and Waikite in New Zealand. Comparison with the calcite dendrite crystals found at those sites shows that dendrite morphology is site-specific and probably controlled by carbonate saturation levels that, in turn, are controlled by the rate of CO2 degassing and location in the spring outflow system.  相似文献   

15.
Late Quaternary travertines deposited from hot springs can reveal much about the neotectonic attributes and histories of structures. On the basis of field studies in the Aegean region (Turkey and Greece), the northern Apennines (Italy) and the Basin and Range province (USA) we conclude that the following relationships are of predictive value: (i) travertine deposits are preferentially located along fracture traces, either immediately above extensional fissures or in the hanging walls of normal faults; (ii) the locations of many travertine fissure-ridge deposits coincide with step-over zones (relay ramps) between fault segments; networks of intersecting tensional fissures reflecting the complex strains experienced in such settings are probably responsible for enhancing hydrothermal flow; (iii) the morphology of travertine deposits overlying extensional fissures is controlled by the rheology of the underlying materials; tufa cones (towers, pinnacles) form on former and present lake floors where fissures underlie unconsolidated sediments, whereas fissure-ridges develop where fissures cut bedrocks at the surface; (iv) fissure-ridges comprise outwardly dipping bedded travertine flanking a central tensional fissure filled by vertically banded travertines; fissures can be used to infer local stretching directions; (v) where there are travertines datable by the U-series method it is possible to calculate time-averaged dilation and lateral propagation rates for individual fissures; (vi) most fissures cutting fissure-ridges comprise self-similar angular segments with fractal dimensions in the range 1.00–1.12, the properties of bedded travertine combined with stress perturbations at fissure tips probably being responsible for such similar fractal dimensions being inferred from such a wide range of locations. Fissures gradually increasing in width with depth are products of continuous fracture dilation in contrast to those that form during episodic dilation which display stepped increases of width with depth; (vii) travertine deposited from springs along fault zones accumulate in terraced-mounds sited down slope of the spring line; (viii) many post-depositional fractures cutting travertine deposits are locally oriented at right angles to deposit margins; and (ix) systematic joints in travertines are restricted to those parts of eroded sheet deposits that have been exhumed.  相似文献   

16.
The relict Fairmont Hot Springs deposit, formed largely of carbonates, covers an area of 0·5 km2, and is up to 16 m thick. The triangle‐shaped discharge apron, which broadens down‐valley, is divided into a proximal part with beds dipping at <10° and a distal part with beds dipping at 10° to 15°. The deposit is formed of the: (1) Basal Macrophyte; (2) Lower Carbonate; (3) Middle Clastic; (4) Upper Carbonate; and (5) Upper Clastic Sequences. Two charcoal samples embedded in the Lower Carbonate Sequence yielded dates of 8690 ± 90 and 8270 ± 70 cal yr bp , indicating that much of the deposit formed post‐glacially during the Early to Mid‐Holocene. Deposit aggradation ceased in the Mid to Late Holocene when the Fairmont Creek valley was incised. The Lower and Upper Carbonate Sequences, which are the thickest sequences, are composed of nearly equal parts of travertine (abiotic) and tufa (biotic), with feather dendrite travertine, radiating dendrite travertine and stromatolite tufa dominating. Competition between calcite precipitation rates and biotic growth rates controlled the distribution of tufa and travertine across the discharge apron. Calcite and biotic growth rates were controlled largely by flow velocity across the apron which, in turn, was controlled by topography and regular fluctuations in spring water discharge volume. During times of high spring discharge, slow sheet flow over the proximal part of the apron promoted stromatolite growth, whereas fast, turbulent flow on the distal part of the apron induced rapid feather dendrite formation. During times of low spring discharge, quiescent, shallow evaporative pools, conducive to radiating dendrite formation, formed on the proximal part of the apron, whereas slow flow on the distal part promoted stromatolite growth. Facies with high calcite supersaturation experienced rapid abiotic dendrite growth that precluded most biotic growth.  相似文献   

17.
Travertine is present at 20% of the ca 60 hot springs that discharge on Loburu delta plain on the western margin of saline, alkaline Lake Bogoria in the Kenya Rift. Much of the travertine, which forms mounds, low terraces and pool‐rim dams, is sub‐fossil (relict) and undergoing erosion, but calcite‐encrusted artefacts show that carbonate is actively precipitating at several springs. Most of the springs discharge alkaline (pH: 8·3 to 8·9), Na‐HCO3 waters containing little Ca (<2 mg l?1) at temperatures of 94 to 97·5°C. These travertines are unusual because most probably precipitated at temperatures of >80°C. The travertines are composed mainly of dendritic and platy calcite, with minor Mg‐silicates, aragonite, fluorite and opaline silica. Calcite precipitation is attributed mainly to rapid CO2 degassing, which led to high‐disequilibrium crystal morphologies. Stratigraphic evidence shows that the travertine formed during several stages separated by intervals of non‐deposition. Radiometric ages imply that the main phase of travertine formation occurred during the late Pleistocene (ca 32 to 35 ka). Periods of precipitation were influenced strongly by fluctuations in lake level, mostly under climate control, and by related changes in the depth of boiling. During relatively arid phases, meteoric recharge of ground water declines, the lake is low and becomes hypersaline, and the reduced hydrostatic pressure lowers the level of boiling in the plumbing system of the hot springs. Any carbonate precipitation then occurs below the land surface. During humid phases, the dilute meteoric recharge increases, enhancing geothermal circulation, but the rising lake waters, which become relatively dilute, flood most spring vents. Much of the aqueous Ca2+ then precipitates as lacustrine stromatolites on shallow firm substrates, including submerged older travertines. Optimal conditions for subaerial travertine precipitation at Loburu occur when the lake is at intermediate levels, and may be favoured during transitions from humid to drier conditions.  相似文献   

18.
A method of combining hydrochemical data logging and in situ titrating with measurement of stable carbon and oxygen isotopes was used to reveal the hydrochemical and isotopic characteristics in the Baishuitai travertine scenic area of SW China. It was found that the travertine-forming springs have a very high concentration of calcium and bicarbonate, and accordingly very high CO2 partial pressures, which are not likely to be produced by biological activity in soil alone. Further analysis of the stable carbon isotopes of the springs shows that the high pressure of CO2 is mainly related to an endogenic CO2 source. That means the Baishuitai travertine is endogenic in origin. This is contrast to the commonly accepted saying that the travertine deposition in this study simply is a product of warm and humid conditions in a karst ecological environment. Rapid CO2 degassing from the water is triggered by the much higher partial pressures in water than that of the surrounding air. Consequently, as the waters flow downstream of the spring the pH increases, the waters become supersaturated with respect to calcite, and travertine is deposited. The preferential release of 12CO2 to the atmosphere results in a progressive increase of travertine 13C downstream. This is concluded with a preliminary discussion of variation in travertine-forming water temperatures, according to differences in stable oxygen isotopic compositions of the travertine formed in different epochs at Baishuitai. It was found that the change in water temperature is as high as 13 °C, i.e., from 23 °C at about 2500 years b.p., to 10 °C at present. This may mainly reflect that the effect of geothermal source on water temperature is decreasing. The problems involved in paleoenvironmental reconstruction with endogene travertine are also discussed. They are the impacts of "dead carbon" in radiocarbon dating and the enrichment in 13C of travertine by endogenic CO2 and degassing of CO2 from water, which has to be considered in paleovegetation reconstruction when using 13C data of the endogene carbonate deposits.  相似文献   

19.
Characterization of a Pleistocene thermal spring in Mozambique   总被引：1，自引：1，他引：0  
A hydrogeological study was conducted with the objective to investigate the only currently known hot spring of Sofala Province in Mozambique with respect to the origin of the water, the discharge, and its chemical composition. Field investigations comprised a general land use survey, mapping of sediment and water temperatures, discharge measurements and on-site water chemistry as well as sampling for further chemical analyses and groundwater dating. Thermal water discharge occurs along a 100 m long NE–SW zone with water temperatures ranging from 42 to 64.5°C. The thermal water is a low-mineralized sodium-chloride-sulfate water enriched in phosphate, fluorine and nickel. The silica geothermometer, the silica concentration of 43 mg/kg and the ratios of Br/Cl and I/Cl of 2.5?×?10–3, suggest that the thermal water stems from approximately 5,000 m depth and had a long residence time with silicate rocks. This points towards Gorongosa Mountain as the water source area. 14C dating suggests a groundwater age of 11,000 years.  相似文献   

20.
富含Ca2+ 和HCO3-的水体是黄龙钙华地貌得以持续沉积的首要条件。为明确2017年九寨沟“8·8”地震是否对黄龙脆弱钙华体产生影响并进而导致水环境的改变,于2017年10月和2018年8月对黄龙3个主要监测点进行了水样采集和水质参数检测。通过主成分分析震前的多次水质检测结果,得到影响黄龙水化学的主要参数,并与震后的水化学参数进行对比分析,发现:2016年（震前）水质参数显示pH、总磷、总氮对黄龙水质起主要贡献作用,地震后水体的pH、Ca2+ 和HCO3-含量上升,而总磷含量则下降较多,表明地震对黄龙钙华体内部结构产生了影响,导致上升泉（转花泉）中的Ca2+ 和HCO3- 含量增加,并影响了pH,而震后水体中的总磷含量减少,这可能与游客数量大幅度减少有关;“8·8”地震对黄龙钙华沉积区水环境造成了影响,并有利于钙华沉积。   相似文献   

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