株洲县湾塘—王家洲区段温泉形成机制及发展前景探讨

通过对株洲县湾塘－王家洲区段地层、构造、水文、岩浆岩的研究，探讨了本区温泉的形成机制，根据温泉的特征，将本区温泉分为低温温泉和中温温泉两类；运用水文地质的研究方法对本区的地下热水水质、水温和可供开采有补给保证的地下热水资源量进行了科学的分析计算和概括；从经济和社会效益角角对本区温泉的开发前景进行了探讨。     

Chemistry of the 350°C hot springs on the crest of the East Pacific rise at 21°N

Hydrothermal fields on submarine spreading centres were first studied systematically during dives of the deep submersible ALVIN on the crest of the Galapagos Ridge in 86°W in the spring of 1977. While the exiting waters had temperatures only about 20°C above that of the ambient water column detailed analysis of their chemistry showed them to be formed by mixing of cold sea water (as “ground-water”) with a hydrothermal endmember of approximate temperature 350°C. Subsequently fields of hot springs with this temperature were found on the crest of the East Pacific Rise at 21°N by ALVIN in 2 600 metres water depth. Reconnaissance water sampling of these systems was made in November 1979 and a detailed study has just been completed (November 1981).The 350°C solutions are completely depleted of their original sea-water concentrations of Mg and SO₄. They are acid with a pH (25°C, 1 atmos) of 3.6 and an acidity of 400 μeq/kg. They contain about 7 mmol/kg of H₂S. The isotopic composition of this sulphur and the arsenic to sulphur ratio in the solutions indicate that about 85% of it is of igneous origin. The “soluble elements” Li, K and Rb are strongly enriched over the sea-water values, as are Ca and Ba. Sr is present at close to the sea-water concentrations however the isotopic compositon is identical to that of the basalts. The exiting solutions are clear and homogeneous super-critical fluids of in situ density approximately 0.65 g/cm³. Velocities in the throat of the orifices are around 1.5 m/sec. The iron concentrations are 1.8 mmol/kg and the Fe/Mn ratio is about 3. The reconnaissance samples gave Zn of 120 μol/kg and Cu and Ni of about 15 μol/kg.Upon mixing with sea-water the hot springs precipitate a voluminous black “smoke” predominantly composed of fine-grained FeS. Anhydrite is precipitated around the throat of the orifice producing chimney-like constructional features up to 10-m high. As these grow vertically the anydrite is replaced by sulphide minerals. The outer surface of the chimneys is colonized by several species of worms that secrete mats of tubes, up to several centimetres in diameter, composed of a tough organic material. Lateral growth of the chimneys via leaks in their walls leads to precipitation of sulphide minerals in a morphology controlled by the organic mats. All the numerous extinct sulphide deposits in the area have this characteristic surface texture.The active deposits on the EPR are unlike ophiolite type massive sulphides chemically, mineralogically and texturally. However, they do represent the primary precipitate. It appears that during lateral growth and coalescence of the chimneys in a given field the original deposit is reworked chemically as the 350°C solutions stream through the disequilibrium rapidly precipitated material. A “zone refined” substrate results consisting of coarsely crystalline, permeable relatively pure pyrite. This secondary deposit is, of course, capped with juvenile chimneys. It is these that probably constitute the ochres, the oxidized surficial zones of massive sulphides historically worked for silver and other elements present at only trace levels in the bulk deposit.     

Some geothermal springs of Nepal

Almost all known thermal springs in Nepal are localized close to and south of either the Main central Thrust or the Main Boundary Fault, and therefore they fall broadly into two major groups. The results from four thermal springs — two from each group — are discussed here. The temperature of the spring water is up to 50°C above normal atmospheric temperature. The waters of almost all springs are alkaline. The dissolved silica content and atomic ratio of Na and K do not indicate any high subsurface temperature and therefore the thermal springs are considered to be of tectonic origin.     

Oxygen and hydrogen isotope geochemistry of thermal springs of the Western Cape, South Africa: Recharge at high altitude?

A number of thermal springs with temperature up to 64°C are found in the Western Cape Province of South Africa. The average δ¹³C value of gas (CO₂+CH₄) released at three springs is −22, which is consistent with an entirely biogenic origin for the C and supports previous investigations which showed that the springs are not associated with recent or nascent volcanic activity. Most springs issue from rocks of the Table Mountain Group, where faulted and highly jointed quartzites and sandstones of the Cape Fold Belt act as the main deep aquifer. The δD and δ¹⁸O values of the springs range from −46 to −18 and from −7.3 to −3.9, respectively. Although the thermal springs have isotope compositions that plot close to the local meteoric water line, their δD and δ¹⁸O values are significantly lower than ambient meteoric water or groundwater. It is, therefore, suggested that the recharge of most of the thermal springs is at a significantly higher altitude than the spring itself. The isotope ratios decrease wuth increasing distance from the west coast of South Africa, which is in part related to the continental effect. However, a negative correlation between the spring water temperature and the δ¹⁸O value in the thermal springs closest to the west coast indicates a progressive in increase in the average altitude of recharge away from the coast.     

Les lithophages pliocènes de la fontaine de Vaucluse (Vaucluse, France). Un argument pour une phase messinienne dans la genèse du plus grand karst noyé de France

The discovery of a level of lithophaga in the entrance of the karstic spring of the ‘Fontaine de Vaucluse’ indicates a pre-Pliocene age and supports a Messinian origin for the present spring. To cite this article: É. Gilli, P. Audra, C. R. Geoscience 336 (2004).     

Étude du fonctionnement du système aquifére karstique Cénomano-Turonien de l'oued Igrounzar, bassin d'Essaouira, Maroc

In the Meskala-Kourimat area, the Bouabout Syncline aquifer system, intersected by the Igrounzar Wadi, feeds most of the karstic sources of the region. This aquifer is contained within Cenomanian and Turonian limestones and dolomitic limestones. The base of the system corresponds to the lower Cenomanian grey clays, and the top to the Senonian white marls. Hydrodynamic studies of various springs shows that each water source is different from the other, indicating a heterogeneous underground reservoir belonging to a complex karst system. The springs waters show a large chemical variability in space and time. These waters are a mixture of chloride, sulphate, Na and Mg. High Mg contents of some springs result from dissolution of evaporite, confirmed by low Ca/Mg ratios. The total dissolved solids (TDS) in spring water increases from upstream to downstream, probably as a response to residency time, but also due to interaction with Cenomanian evaporites. However, the springs are good for drinking water, as well as for irrigation. The monthly survey of selected springs indicated a large chemical variability but with little or no correlation between discharge and TDS.Stable isotope data (¹⁸O) suggests that the altitude of the recharge area, for this aquifer system, is 1200 m. The ¹⁸O gradient versus altitude, established on springs whose recharge areas are well known is, −0.25% versus SMOW/100 m. When compared with the ‘Meteoric Water Line’ established on worldwide spring water whose recharge areas are well known, the Essaouira Basin shows rain recharge without any significant evaporation.     

Analysis of the environmental sensitivities of a typical dynamic epikarst system at the Nongla monitoring site, Guangxi, China

Nongla, a typical karst dynamic system (KDS) monitoring site, is located at Nongla Village, Mashan County, Guangxi, China. The data from a Greenspan CTDP300 multichannel data logger indicates that the KDS is highly sensitive to environmental changes. Multi-day and diurnal physico-chemical composition of epikarst spring water is quite different under different climatic conditions. During a day with no rainfall, water temperature and air temperature have similar variations. Electrical conductivity (EC) has good positive correlation with pH value and water temperature. During rainstorms, the physico-chemical composition of the spring water is initially strongly effected by dilution, pH and EC drop rapidly. However, half to one hour later, EC returns to normal and the CO₂ effects will be the dominant physical effect. This is due to the high fissure rates and high permeability in the epikarst zone. Dilution effects were observed during the entire rainstorm event,whereas, it only acts during the earliest period of light rain. Therefore, it is necessary to examine the water–rock–CO₂ combination as a whole system to explain the hydrochemical behavior of epikarst processes.     

Validation of a chrysophyte stomatocyst‐based cold‐season climate reconstruction from high‐Alpine Lake Silvaplana,Switzerland

For the reliable assessment of past climate variability, quantitative reconstructions of seasonal temperatures are required. Currently, reconstructions of cold‐season temperatures are scarce, because most biological proxies are biased towards the growing season. Here we test the potential of chrysophyte stomatocysts (or simply ‘cysts’; siliceous resting stages of the golden‐brown algae) as a proxy for cold‐season temperature. Climate reconstructions based on biological proxies are commonly constructed using transfer functions derived from calibration in space. However, the performance of these reconstructions is rarely tested by direct comparison with meteorological data due to limitations of sample resolution or chronological control. We compare a cyst‐based near‐annual reconstruction of ‘date of spring mixing’ from the varved sediments of Lake Silvaplana (Swiss Alps) spanning AD 1870–2004 with climate variables from the same period measured at the lake shore. The high correlation between cyst‐based ‘date of spring mixing’ and cold‐season temperature demonstrates the ability of chrysophyte cysts to archive cold‐season temperature variability. Lake eutrophication, which was extensive during the last 50 years, had no obvious effect on the cyst‐based reconstruction. This study underlines the high potential of chrysophyte cysts as a quantitative proxy for cold‐season climate reconstructions. Copyright © 2011 John Wiley & Sons, Ltd.     

成都市白马泉增温特征及成因模式研究

在分析白马泉地区的构造、地下水水温、地温及地下水中游离ＣＯ２等增温异常特征的基础上,提出白马泉的成因模式,为研究区内低温热水提供了较为充分的理论依据。     

La vague de chaleur de l'été 2003 et sa prévision saisonnière

The main features of the heat wave that has affected western Europe during the summer 2003 are first recalled, with particular concern to analogies and differences with previous warm-summer episodes. The skills of the various operational and pre-operational seasonal forecasting models in use at that time are evaluated. None of them has been able to consistently forecast the heat wave three month in advance. The meteorological and climatic situation prevailing during spring 2003 is then analysed. A strong sea-surface-temperature (SST) anomaly is found to have developed over North Atlantic a few months before the heat wave. The particular mechanism at work to explain the occurrence of the heat wave is not a ‘simple downwind influence’ of the SST anomaly. It very likely involves complex ocean–atmosphere interaction phenomena of a kind that is not properly taken into account in today's seasonal forecasting models. To cite this article: J.-C. André et al., C. R. Geoscience 336 (2004).     

Cu–Ni–Co–As (U) mineralization in the Anarak area of central Iran

Cu–Ni–Co–As–U mineralization in the Anarak area of central Iran occurs at the intersection of the Uroumieh-Dokhtar magmatic belt with the Great Kavir–Doruneh fault. In the area, the volcanism associated with the magmatic belt is shoshonitic in character. Chemical analyses indicate that these are subduction related magmas. Detailed investigations in the vicinity of the Talmessi mine indicate that mineralization occurred in two separate stages: a first stage of copper sulphide mineralization with a relatively simple mineralogy and associated with the Eocene magmatism, and a second stage of Cu–Ni–Co–As–U mineralization with a complex mineralogy, which probably formed during another phase of deformation in the Upper Miocene. This later deformation reactivated previously formed faults. The mineralogy, element association and isotopic composition of carbonates for the second phase of mineralization suggest a different origin to that of the first phase. The fluids are likely to be non-magmatic in origin, possibly showing an increased input from meteoric waters. The close spatial association with basic/ultrabasic igneous rocks indicates that these may be the source through alteration and remobilization. The arsenide mineralization in the Anarak area shows many features that are similar to those of the classic five-element deposits.     

Variability in temperature and geometry of the Norwegian Current over the past 600 yr; stable isotope and grain size evidence from the Norwegian margin

Core P1‐003MC was retrieved from 851 m water depth on the southern Norwegian continental margin, close to the boundary between the Norwegian Current (NC) and the underlying cold Norwegian Sea Deep Water. The core chronology was established by using ²¹⁰Pb measurements and ¹⁴C dates, suggesting a sampling resolution of between 2 and 9 yr. Sea‐surface temperature (SST) variations in the NC are reconstructed from stable oxygen isotope measurements in two planktonic Foraminifera species, Neogloboquadrina pachyderma (d.) and Globigerina bulloides. The high temporal resolution of the SST proxy records allows direct comparison with instrumental ocean temperature measurements from Ocean Weather Ship (OWS) Mike in the Norwegian Sea and an air temperature record from the coastal island Ona, western Norway. The comparison of the instrumental and the proxy SST data suggests that N. pachyderma (d.) calcify during summer, whereas G. bulloides calcify during spring. The δ¹⁸O records of both species suggest that the past 70 yr have been the warmest throughout the past 600 yr. The spring and summer proxy temperature data suggest differences in the duration of the cold period of the Little Ice Age. The spring temperature was 1–3°C colder throughout most of the period between ca. AD 1400 and 1700, and the summer temperature was 1–2°C colder throughout most of the period between ca. AD 1400 and 1920. Fluctuations in the depth of the lower boundary of the NC have been investigated by examining grain size data and benthic foraminiferal assemblages. The data show that the transition depth of the lower boundary of the NC was deeper between ca. AD 1400 and 1650 than after ca. AD 1750 until present. Copyright © 2003 John Wiley & Sons, Ltd.     

Hydrogeochemistry and geothermometry of thermal springs from the Guelma region,Algeria

This paper reports the results of our studies, the chemical analysis of thermal spring’s waters and their geological settings, the use of different statistical methods to evaluate the origin of the dissolved constituents of spring waters and the estimation of the reservoir temperature of the associated geothermal fields of the Guelma region, Algeria. A major component in 13 spring water samples was analyzed using various techniques. The waters of the thermal springs at Guelma basin vary in temperature between 20 and 94oC. Q-mode hierarchical cluster analysis suggests three groups. The water springs were classified as low, moderate and high salinity. Mineral saturation indices (SI) calculated from major ions indicate the spring waters are supersaturated with the most of the carbonate minerals, and all of the spring water samples are under-saturated with evaporite minerals. The thermal spring waters have a meteoric origin, and all samples are immature with strong mixing between warm and shallow waters, where the temperatures of reservoirs to which the thermal waters are related ranged between 64° and 124°C. The deep circulation of meteoric waters in the study area is supplied by the high geothermal gradient around 4.5°C per 100 m and reaches a high temperature before rising to the surface. The estimated circulation depths ranged from 1425 and 3542 m.     

Spinel–quartz high temperature paragenesis in Al–Fe granulites from the Ihouhaouene area (NW Hoggar, Algeria)

The spinel–quartz-bearing Al–Fe granulites from Ihouhaouene (In Ouzzal, West Hoggar) have a migmatitic appearance with quartzo-feldspathic layers intercalated with restitic layers. These granulites are characterized by a hercynitic spinel–quartz assemblage typical of high grade terranes. The stability of the spinel–quartz assemblage is attributed to an elevation of temperature (from 800 to >1100 °C) at high pressures (10–11 kbar), followed by an isothermal decompression from 9 to 5 kbar, an evolution typical of the In Ouzzal clockwise P–T path. The Al–Fe granulites’ history can be subdivided into different successive crystallisation stages. During the first stage, the spinel–quartz assemblage formed, probably following a prograde event that also produced partial melting. During a second stage, the primary spinel–garnet–sillimanite–quartz paragenesis broke-down to give rise to the secondary assemblage. The metamorphic evolution and phase relations during this stage are shown in P–T–X pseudosections calculated for the simple FMASH system. These pseudosections show that the orthopyroxene–cordierite–spinel symplectite appeared during a high temperature decompression, as a product of destabilisation of garnet in sillimanite-free microdomains with high X_Mg values. At the same time, the spinel–quartz association broke-down into cordierite in Fe-rich microdomains. Average pressure and temperature estimates for the orthopyroxene–spinel–garnet–cordierite–quartz association are close to the thermal peak of metamorphism (1000 ± 116 °C at 6.3 ± 0.5 kbar). With decreasing temperatures garnet–sillimanite corona developed from the breakdown of the primary spinel–quartz assemblage in the Fe-rich microdomains, whereas cordierite–spinel formed at the expense of primary sillimanite and garnet in the Mg-rich microdomains.     

Subduction-related hot spring-type gold mineralization in the central Tengchong block,southwestern China

Numerous present-day hot springs and associated ancient Lianghe gold deposit occur in the central Tengchong block, SW China, associated with oceanic crust subduction. From the center outwards, the alteration zones in the hot spring of the Rehai consist of alunite and silica in a breccia zone, a kaolinite and illite zone, and a chlorite, illite, kaolinite zone. The gas phase in the hot spring is dominated by CO₂ with δ¹³C ranging from −4.5‰ to −7.2‰. These features indicate a major magmatic origin of the hot spring gas. The ³He/⁴He ratios in the gas from central Tengchong vary from 1.56 to 5.88, approaching to those of the MORB. This is probably related to the ongoing subduction of the Indian plate beneath the Tengchong block. The hot spring waters in the central Tengchong block have much higher content of Au and other elements, e.g., Ag, As, Sb, and Tl, than other typical hot springs, such as Hasbrouck, Sulfer, etc. in the world. The hot springs with more mantle gas contribution and higher water temperature show more elevated Au contents, which implies that the metal in the hot spring was most likely contributed from the magmatic gas. The compiled D-O isotopes of the hot spring waters from previous studies suggest that they are primarily derived from meteoric water. A genetic model for the hot spring system in the central of Tengchong has been tentatively established. The gold-charged hot spring is genetically connected to an active magma chamber, which was produced by subduction of oceanic crust. The chamber is driving long-term surface meteoric circulation and constantly releasing magmatic volatiles enriched with metals. As hot spring water mixed with magmatic volatiles, causing decompression-boiling and forming hydraulic fractures to penetrate the roof of siliceous sinter, which induced the continuing metal deposition and formed the Lianghe hot spring.     

Talc friction in the temperature range 25°–400 °C: Relevance for Fault-Zone Weakening

Talc is one of the weakest minerals that is associated with fault zones. Triaxial friction experiments conducted on water-saturated talc gouge at room temperature yield values of the coefficient of friction, μ (shear stress, τ/effective normal stress, σ′_N) in the range 0.16–0.23, and μ increases with increasing σ′_N. Talc gouge heated to temperatures of 100°–400 °C is consistently weaker than at room temperature, and μ < 0.1 at slow strain rates in some heated experiments. Talc also is characterized by inherently stable, velocity-strengthening behavior (strength increases with increasing shear rate) at all conditions tested. The low strength of talc is a consequence of its layered crystal structure and, in particular, its very weak interlayer bond. Its hydrophobic character may be responsible for the relatively small increase in μ with increasing σ′_N at room temperature compared to other sheet silicates.Talc has a temperature–pressure range of stability that extends from surficial to eclogite-facies conditions, making it of potential significance in a variety of faulting environments. Talc has been identified in exhumed subduction zone thrusts, in fault gouge collected from oceanic transform and detachment faults associated with rift systems, and recently in serpentinite from the central creeping section of the San Andreas fault. Typically, talc crystallized in the active fault zones as a result of the reaction of ultramafic rocks with silica-saturated hydrothermal fluids. This mode of formation of talc is a prime example of a fault-zone weakening process. Because of its velocity-strengthening behavior, talc may play a role in stabilizing slip at depth in subduction zones and in the creeping faults of central and northern California that are associated with ophiolitic rocks.     

青海高原不同生态功能区气候突变时间的比较分析

根据地理位置和地貌特征将青海省划分为东部农业区、 环青海湖区、 三江源区和柴达木盆地4个生态功能区, 利用这4个生态功能区1961-2010年的月平均气温和降水量资料, 对年和四季的平均气温及总降水量进行了突变检测.结果表明: 4个生态功能区年平均气温和四季气温都呈显著的上升趋势, 其中冬季气温上升最明显, 其次为秋季, 春季和夏季相对较小.气温突变时间检测表明, 年平均气温为柴达木盆地的突变时间最早, 其次为东部农业区和环湖区, 三江源区突变时间最晚.不同生态功能区四季气温突变时间不尽相同.年降水量除柴达木盆地上升趋势明显外, 其余三个地区变化趋势都不明显; 四季降水量变化趋势除冬季降水量变化明显(除东部农业区)外, 其余三季变化趋势基本不明显.降水量突变信号较气温突变信号弱, 只有个别地区的个别季节降水量发生了突变.     

Tree-Ring-Based Spring Temperature Patterns over the Past Four Centuries in Western Himalaya

A network of 12 tree-ring width chronologies of Himalayan cedar (Cedrus deodara) from the western Himalayan region, India, has been used to reconstruct mean spring (March–May) temperature variations back to A.D. 1600. The most conspicuous feature of the temperature reconstruction is the long-term cooling trend since the late 17th century that ended early in the 20th century. The warmest 30-yr mean for the 20th century was recorded during 1945–1974. However, this warming, in the context of the past four centuries is well within the range of natural variability, since warmer springs of greater magnitude occurred in the later part of the 17th century (1662–1691).     

Hydrothermal deposition on the East Pacific rise at 21°N

In the spring of 1979, 350°C springs precipitating hydrothermal sulphides and sulphates directly on to the sea-floor were discovered on the crest of the East Pacific Rise (EPR) at 21°N by the astonished scientific party of the RISE submersible expedition. These hot springs are within a linear field of active and inactive hydrothermal vents extending 6 km along the rise axis. Typically the mineral deposits at EPR, 21°N consist of basal sulphide mounds surmounted by mineralized sulphide-sulphate edifices, or “chimneys”, reaching heights up to 13 m above the sea floor. The mounds rest directly on fresh basalt and cover areas up to 450 m². Chimneys atop mounds may be active or dead. The hottest active chimneys (350°C) spew forth fluids blackened by fine-grained sulphide precipitates, dominantly hexagonal pyrrhotite and iron-rich sphalerite. These “black smokers” are distinguished from cooler “white smoker” chimneys which are encrusted by worm tubes and emit milky fluids bearing amorphous silica, barite, and pyrite.     

黑龙江省春季浅层(0～20cm)地温变化特征及预报

利用1981-2012年黑龙江省74个气象观测站的气温、0 cm、10 cm、20 cm地温春季(3-5月)逐日资料,分析了黑龙江省春季浅层地温、气温变化特征.结果表明:0 cm地温年际间波动大,全省平均1987年最低,2008年最高;全省变化存在明显的空间一致性;尽管气候变暖使1990年代以后春季0 cm地温偏低年出现相对减少,但是出现春季浅层地温偏低的年份比例仍超过三分之一,并具有南部、北部反向变化的特征,2005年以后南北差异有减小的趋势.各地3月份开始解冻,主要农区10 cm地温稳定通过6℃的日期主要集中在4月中下旬.以10 cm地温为预报量,利用黑龙江省逐日气温、20 cm地温资料建立春季浅层地温预报模型,回代和2013年预报检验平均绝对误差平均为1.05℃,绝对误差最大值为1.9℃,4月份的预报结果要好于3、5月,可以应用于业务指导.