temperatures at the base of the laurentide ice sheet inferred from borehole temperature data 1 we use temperature profiles from 4 deep 1600 m boreholes across canada to determine ground surface temperature histories gsth s through and after the last glacial maximum lgm inversion yields the temperature history at the base of the glacier and the surface temperature evolution after the glacial retreat the results indicate geographic differences in basal temperature history across the ice sheet during the last glacial maximum temperatures at the base of the ice sheet were lower in eastern canada at the southeastern edge of the glacier than in central canada southwest of the glacier center at all sites basal temperatures were above the melting point of ice during and after the lgm which may explain the highly unstable character of the ice sheet the gsth s are consistent with information on the history of the laurentide ice sheet and provide quantitative constraints on glacier flow dynamics

the role of oceanic forcing in mid holocene northern hemisphere climatic change previous model investigations suggested that changes in orbital forcing and feedbacks associated with northward expansion of the boreal forest were both required to explain the full magnitude of enhanced high latitude northern hemisphere summer warming at 6 ka thus implying that biospheric feedbacks decreased planetary albedo associated with forest expansion may be large in the future foley et al 1994 tempo testing earth system models with paleo observations 1996 before the magnitude of past biospheric and other feedbacks can be estimated with confidence however the role of realistic high latitude oceanic forcing i e sea surface temperature sst increases and sea ice reductions should also be considered here we review existing paleoceanographic observations that suggest portions of the north atlantic were up to 4 c warmer than today at 6 ka we then combine our estimates of mid holocene north atlantic sst and sea ice conditions with new climate model simulations to suggest that a significant portion of high latitude summer warming at 6 ka in the northern hemisphere can be accounted for by altered orbital forcing ssts and sea ice relative to today our results underscore the importance of incorporating realistic boundary conditions when using paleoenvironmental data to evaluate the climate system s sensitivity to altered forcing and suggest that high latitude oceanic feedbacks were major contributors to enhanced high latitude summer warming in the northern hemisphere at 6 ka

heat flow heat production relationship not found what drives heat flow variability of the western canadian foreland basin heat flow high 80 10 mw m2 in the northern western parts of the western canadian foreland basin is in large contrast to low heat flow to the south and east 50 7 mw m2 of the same basin with the same old 2e09 year s precambrian basement and some 200 km thick lithosphere over thrusted and flat laying sedimentary units are heated from below by heat flow from the old craton crust and low 15 5 mw m2 mantle contribution the heat flow vs radiogenic heat production statistical relationship is not found for this area to account for this large heat flow contrast and to have 200 km thick lithosphere we would need to assume that high heat production layer of the upper crust varies in thickness as much as factor of 2 and or that the measured heat production at top of precambrian basement is not representative for deeper rocks the other explanation proposed before that heat in the basin is redistributed by the regional fluid flow systems driven from high hydraulic head areas close to the foothills of the rocky mountains toward low elevation areas to the east and north cannot be explained by observed low darcy fluid velocities and the geometry of the basin

chemical and isotopic characteristics of geothermal fluids from sulphur springs saint lucia abstract sulphur springs is a vigorous geothermal field associated with the active soufriere volcanic centre in southern saint lucia lesser antilles island arc the sulphur springs park is an important tourist attraction touted as the world s only drive through volcano with some of the hot pools being developed into recreational pools some 200 000 people visit the park each year since 2001 the hydrothermal fluids of sulphur springs have been sampled as part of an integrated volcanic monitoring programme for the island gas and water samples were analysed to characterise the geochemistry of the hydrothermal system and to assess the equilibrium state and subsurface temperatures of the reservoir this has also enabled us for the first time to establish baseline data for future geochemical monitoring the gases are of typical arc type composition with n2 excess and low he and ar content the dry gas composition is dominated by co2 ranging from 601 993 mmol mol with deeper magmatic sourced h2s rich vapour undergoing boiling and redox changes in the geothermal reservoir to emerge with a hydrothermal signature in the fumarolic gases fluid contributions from magmatic degassing are also evident mainly from the moderate to high contents of hcl and deeply sourced h2s gas respectively sulphur springs hydrothermal waters have acid sulphate type compositions so4 78 4008 mg l ph 3 7 and are of primarily meteoric origin which have been affected by evaporation processes based on the enrichment in both 18o and d 18o 1 to 15 and d 9 to 14 respectively in relation to the global meteoric water line gmwl these waters are steam heated water typically formed by absorption of h2s rich gases in the near surface oxygenated groundwaters reservoir temperatures calculated from the evaluation of gas equilibria in the co2 ch4 h2 system reveal higher temperatures 190 to 300 c than those derived from quartz geothermometry 95 to 169 c which appeared to be affected by dilution with meteoric waters generally no significant variations in fluid geochemistry of the hydrothermal system were observed between 2001 and 2006 and we propose that there were no changes in the state of volcanic activity during this period

ground surface temperature history in poland in the 16th 20th centuries derived from the inversion of geothermal profiles ground surface temperature gst history in poland was derived from the inversion of temperature depth profiles in over 20 wells temperature histories for the period 1500 a d through 1977 a d agree well with the instrumental record of the surface air temperature available for the last two centuries a statistical correlation of the reconstructed histories from the well temperature data with the instrumental record air temperature from the homogeneous warsaw series is high 0 8 functional space inversion fsi of the temperature data with depth shows that beginning in the early 19th century temperatures warmed by 0 9 0 1 c following a long period of colder climate before the last number could be a minimal as higher warming was calculated using a simple model based on surface temperature for the observational period homogenized warsaw surface temperature series lorenc 2000 and pom pre observational mean harris and chapman 1998 of 1 53oc below the 1951 1980 mean temperature level

holocene history of the estuarine area surrounding portage alaska as recorded in a 93 m core a 93 m core obtained at portage alaska records four prograding cycles of estuarine deposition for the past 8230 100 years analyses of texture mineralogy paleontology and sedimentary structures enable definition of eight lithologic units mineralogic studies show that past and present sedimentation at portage has been largely mud and sand from the susitna river on the northwest side of cook inlet six radiocarbon dates from concentrated organic debris in the core and on the surface enable determination of sedimentation rates for four intervals and show rates to be higher and to vary more at depth than rates nearer the surface the glacier carved turnagain arm fiord has been receiving sediment for at least the past 14 000 years as estimated by extrapolation of calculated sedimentation rates to the thickness of unconsolidated sediment drilled at portage which totals approximately 300 m presently deposition is accomplished instantly as the result of tectonic subsidence and compaction of sediment

lake sediment evidence for the date of deglaciation of the hidden lake area kenai peninsula alaska an abrupt environmental change is reflected in a core from hidden lake alaska by differences in sediment type chlorite crystallinity and content of organic carbon and water of the sediments this abrupt change in the sedimentary record occurred about 14 500 14c yr ago and probably marks the time of recession of the glacier from the hidden lake drainage basin deglaciation of the area was then underway and rock flour was being deposited in the lake after recession of the glacier from the hidden lake drainage basin rock flour was no longer introduced and organic matter content of the sediment increased by the dating of these changes in sediment type we show that retreat of glaciers in this area took place significantly earlier than previously estimated this agrees with the timing of retreat of alpine glaciers elsewhere in western north america

the origin of solutes within the groundwaters of a high andean aquifer abstract this paper investigates the origin of solutes within the groundwaters of the monturaqui negrillar tilopozo mnt aquifer system within the high andes of the atacama desert that discharges into the salar de atacama key questions include the relative significance of volcanic hydrothermal processes and evaporitic brine recycling over solute supply as well as the pathways of solute ingress to the mnt aquifer system groundwaters were analysed for elemental major minor and trace and isotopic 18o 2h 13c dic 34s so4 87sr 86sr constituents to which various hydrochemical and multivariate statistical methods have been applied groundwaters are all classified as thermal and show increasing temperatures 27 35 c and concentrations of hco3 4 4 10 4 mmol l 1 dissolved inorganic carbon dic with increasing proximity to volcano socompa resulting from an increasing mass flux of steam and magmatic co2 pco2 0 016 to 0 10 atm 13c co2 9 3 to 3 6 v pdb boiled off a deep hydrothermal reservoir superimposed upon this gradational and relatively smooth spatial increase in heat and mass flow is a sharp structurally controlled increase in tds 826 3632 mg l 1 and a concomitant change in 34s so4 0 79 to 4 9 v cdt and 87sr 86sr values 0 707375 0 706859 associated with the inflow of evaporitic solutes evaporitic inputs are chemically and isotopically distinct from localised secondary hydrothermally derived solutes with major minor and trace element data suggesting an origin within a highly oxidising alkaline evaporitic lake receiving dilute inflows enriched in volcanic fumarolic sulfur mineralisation probably from volcanoes socompa salin or pular that delimit the eastern topographic extent of the aquifer system the conceptual model presented in this paper proposes that basal leakage of evaporitic brines from active salar s within the high altiplano volcanic arc are actively entrained by sub regional groundwater flow and conveyed to the mnt aquifer system where they mix with solutes derived from localised secondary hydrothermal gas water rock interaction this work provides detail on the origin and processes controlling the solute composition of groundwater inflows to the salar de atacama within the volcanically active and hyperarid atacama desert and may be of significance to conceptual models of evaporitic brine evolution recycling of evaporitic brines and hydrothermalism in arid regions

palaeoclimate and structure the most important factors controlling subsurface temperatures in crystalline rocks a case history from outokumpu eastern finland summary the present work contributes to the study of heat transfer mechanisms in crystalline bedrock we present evidence from a thoroughly investigated case history in outokumpu eastern finland in the fennoscandian or baltic shield which shows that the subsurface temperature field is controlled by the thermal conductivity structure and downward diffusion of palaeoclimatic ground temperature variations the subsurface temperature profiles from three continuously cored boreholes 790 1 100 m deep were used for a detailed 2 d modelling of structural hydrogeological and palaeoclimatic effects on the subsurface temperature field the boreholes are situated in a subdued topography and they intersect early precambrian folded lithologies such as mica gneisses black schists skarn rocks quartzites and serpentinite talc rocks finitedifference techniques were used in the numerical solution of the heat and masstransport equations the 2 d models of thermal conductivity and hydraulic permeability that were compiled were based on an extensive set of data relating to geological structure in situ hydraulic permeability groundwater composition and thermal conductivity of drill core samples down to about 1 km depth it was found that the thermal effect of topographically driven groundwater convection is very small with peclet numbers typically of the order of 10 4 10 5 the effect of anisotropy of thermal conductivity was found to be one order of magnitude smaller than the effects of heatflow refraction in the inclined rock layers which produce horizontal components of heat flow density ranging from 15 to 5 mw m basal heat flow 35 mw m since the advective heat transfer could be neglected we tried to find a palaeoclimatic groundtemperature history that would explain the measured data first an inversion algorithm based on heat conduction in laterally homogeneous media was used for the reconstruction of palaeoclimatic ground temperature history but it yielded spurious results because of the strong 2 d conductivity effects the only means to reconstruct the past ground temperature changes was forward modelling using a conductive transient 2 d model with time dependent surface temperature variations the surface temperatures at different times between 100000 yr bp and the present and the basal heat flow density were varied in order to reach a reasonable fit between the modelled and measured borehole temperatures to reach this goal the ground temperature history must include the main climatic events during the last 100000 yr such as the last glacial epoch and the little ice age from about 1300 ad to 1700 ad followed by warmer temperatures in more recent times our results suggests that subsurface temperatures in conditions similar to those of the outokumpu case can yield a wealth of palaeoclimatic information when an appropriate approach for modelling heat transfer in the bedrock is chosen

hydrogeochemistry of thermal and mineral water springs of the azores archipelago portugal abstract mineral and thermal water chemistry from the azores archipelago was investigated in order to discriminate among hydrochemical facies and isotopic groups and identify the major geochemical processes that affect water composition a systematic geochemical survey of mineral and thermal water chemistry was carried out incorporating new data as well as results from the literature the azores are a volcanic archipelago consisting of nine islands and samples were collected at sao miguel graciosa faial sao jorge pico and flores islands hydrothermal manifestations show the effects of active volcanism on several islands discharges are mainly related to active quaternary central volcanoes of basaltic to trachytic composition but also some springs are related to older dormant or extinct volcanoes multivariate analysis principal component and cluster analysis enables classification of water compositions into 4 groups and interpretation of processes affecting water compositions groups 1 and 2 discharge from perched water bodies and mostly correspond to na hco3 and na hco3 cl type waters these groups comprise of cold thermal 27 c 75 c and boiling waters 92 2 c 93 2 c with a wide tds range 77 3 27 145 7 mg l group 3 is made of samples of dominated na so4 from very acid boiling pools ph range of 2 02 2 27 which are fed by steam heated perched water bodies group 4 is representative of springs from the basal aquifer system and corresponds to na cl type fluids with compositions dominated by seawater results are used to further develop a conceptual model characterizing the geochemical evolution of the studied waters mineral and thermal waters discharging from perched water bodies are of meteoric origin and chemically evolve by absorption of magmatic volatiles co2 and by a limited degree of rock leaching existing data also suggest mixture between cold waters and thermal water water chemistry from springs that discharge from the basal aquifer system evolves by mixing with seawater although processes such as absorption of magmatic volatiles co2 rock leaching and mixture with hydrothermal waters are not excluded by the data because the actual composition of these waters deviates from that expected considering only conservative mixing between fresh and seawater

microfossil analysis of sediments representing the 1964 earthquake exposed at girdwood flats alaska usa abstract diatom pollen foraminifera and thecamoebian assemblages from an outcrop of peat and silt at girdwood flats in the upper turnagain arm of the cook inlet alaska record four phases of relative land and sea level changes the first phase is the development of freshwater swamp above high marsh sediments during relative land uplift caused by strain accumulation along the locked portion of the alaska aleutian subduction zone in second phase the top 2 cm of the peat all microfossil groups record pre seismic relative sea level rise relative land subsidence the third phase is rapid land subsidence 1 7 m during the earthquake of march 1964 that initiated intertidal silt accumulation above the peat the final phase is the colonisation of mudflat by salt marsh communities during post seismic land uplift the microfossil data compare favourably with sequences from washington oregon and british columbia that record late holocene submergence events caused by earthquakes the comparable changes in microfossil assemblages record the different phases of relative land and sea level changes and the magnitude of land subsidence caused by each earthquake expressed relative to the tidal range at the site these results raise the question whether preseismic sea level rise represents any kind of warning of large earthquakes

temperature trends over the past five centuries reconstructed from borehole temperatures for an accurate assessment of the relative roles of natural variability and anthropogenic influence in the earth s climate reconstructions of past temperatures from the pre industrial as well as the industrial period are essential but instrumental records are typically available for no more than the past 150 years therefore reconstructions of pre industrial climate rely principally on traditional climate proxy records each with particular strengths and limitations in representing climatic variability subsurface temperatures comprise an independent archive of past surface temperature changes that is complementary to both the instrumental record and the climate proxies here we use present day temperatures in 616 boreholes from all continents except antarctica to reconstruct century long trends in temperatures over the past 500 years at global hemispheric and continental scales the results confirm the unusual warming of the twentieth century revealed by the instrumental record but suggest that the cumulative change over the past five centuries amounts to about 1 k exceeding recent estimates from conventional climate proxies the strength of temperature reconstructions from boreholes lies in the detection of long term trends complementary to conventional climate proxies but to obtain a complete picture of past warming the differences between the approaches need to be investigated in detail

origin of calcium sulfate type water in the triassic carbonate thermal water system in chongqing china a chemical and isotopic reconnaissance abstract chongqing located in the southwestern china was named as a spa city of the world it s most geothermal reservoirs are developed in carbonate rock aquifers and those thermal waters are characterized by high concentrations of sulfate and low hco3 however little was known about the origin and genesis of those thermal waters which is necessary for their protection and determination of regime of exploitation therefore thermal and surface waters were sampled seasonally and analyzed for hydrogeochemical and isotopic compositions 18o 2h 34s so4 18o so4 to decipher the origin of the thermal waters in the triassic carbonate aquifers in chongqing area key questions include the relative significance of hydrothermal processes and solute supply the results showed that 1 the major chemical composition of analyzed the thermal waters from chongqing area was characterized by ca so4 2 the 2h and 18o values of the thermal waters ranged from 48 6 to 63 1 with an average value of 54 2 and from 6 5 to 9 2 with an average value of 8 0 respectively indicating that the thermal waters originated from the local rain water with an elevation of 415 m to 1453 m above mean sea level 3 the estimated geothermal temperatures varied from 63 8 c to 78 3 c quartz indicating that the depth of the geothermal reservoir varied from 411 m to 1728 m which is located in the lower triassic jialingjiang formation 4 the 34s so42 and 18o so42 in the geothermal waters ranged from 29 7 to 34 1 with a mean value of 32 1 and from 12 5 to 16 5 with a mean value of 15 2 respectively suggesting that the high so42 concentrations resulted mainly from the dissolution of gypsum in the second part of the lower triassic jialingjiang formation 5 three processes of water rock interactions gypsum dissolution carbonate dissolution by carbonic acid and carbonate dissolution by sulfuric acid in the thermal system were unveiled by the hydrogeochemical and isotopic models among these three processes gypsum dissolution seems to be primarily responsible for solute composition of the thermal water this study also indicates the integration of hydrogeochemical and isotopic data is very useful tool to decipher the origin and genesis of the carbonate thermal waters

global glacial isostatic adjustment palaeogeodetic and space geodetic tests of the ice 4g vm2 model analyses of the global process of glacial isostatic adjustment and post glacial relative sea level change continue to deliver important insights into earth system form and process one successful model of the related phenomenology is based upon a spherically symmetric internal viscoelastic structure for the solid earth which has been denoted vm2 and a model of the most recent deglaciation event of the current ice age denoted ice 4g the primary purpose of this paper is to describe several new a posteriori tests that have recently been performed to further investigate the quality of this global solution to the inverse problem for both mantle viscosity and deglaciation history that is posed by the observables associated with this large scale geodynamic phenomenon i focus especially upon the misfits of observations to the theoretical predictions of this model which i am currently using to further refine its properties and upon predictions made using it of geophysical signals that should soon become visible in the context of the gravity recovery and climate experiment grace satellite mission among the required refinements to ice 4g one that is necessary to eliminate a recently revealed misfit to space geodetic constraints on the present day rate of radial motion at the yellowknife location well to the west of hudson bay and a similar misfit to absolute gravity measurements to the southwest of the bay is the insertion of a keewatin dome of thick ice centred over yellowknife with a ridge of ice extending to the south east in the geomorphological literature the existence of such a keewatin dome previously has been hypothesised but chronological control was lacking on the surface features that suggested its former existence an important additional constraint that requires the late glacial existence of this important feature consists of new inferences of the last glacial maximum lowstand of the sea from sites in the far field of the main concentrations of land ice copyright 2002 john wiley sons ltd

the magmatic and hydrothermal dominated fumarolic system at the active crater of lascar volcano northern chile low to high temperature fumaroles discharging from the active crater of lascar volcano northern chile have been collected in november 2002 may 2005 and october 2006 for chemical and isotopic analysis to provide the first geochemical survey on the magmatic hydrothermal system of this active volcano chemical and isotopic gas composition shows direct addition of high temperature fluids from magmatic degassing mainly testified by the very high contents of so2 hcl and hf up to 87 800 29 500 and 2 900 mol mol and the high r ra values up to 7 29 contributions from a hydrothermal source mainly in gas discharges of the active crater rim has also been detected significant variations in fluid chemistry mainly consisting of a general decrease of magmatic related compounds i e so2 have affected the fumarolic system during the period of observation indicating an increase of the influence of the hydrothermal system surrounding the ascending deep fluids the chemical composition of active crater fumaroles has been used to build up a geochemical model describing the main processes that regulate the fluid circulation system of lascar volcano to be utilized in volcanic surveillance

cycle of earthquake induced aggradation and related tidal channel shifting upper turnagain arm alaska usa aggradation of intertidal sediment in upper turnagain arm a macrotidal estuary located in southern alaska near anchorage began because of subsidence caused by sediment consolidation and tectonic lowering of the land during the earthquake of march 27 1964 at the head of the arm decrease in percent sand of surface sediments with time and return of rodents pulmonate gastropods trees bushes and grasses to the intertidal region indicate that the rate of sediment deposition has slowed and the upper turnagain arm area has returned to a state of preearthquake equilibrium only 17 years after the event comparison of channel locations before and after the earthquake indicates the possibility of regional postseismic tilting of the estuary

geothermal evidence of very low glacial temperatures on a rim of the fennoscandian ice sheet 1 the mean ground temperature as low as 10 c and the existence of more than 500 m thick permafrost during the last glacial are apparent from the analysis of deep borehole temperature profiles in north eastern poland the largest thickness of the permafrost and its survival deep into the holocene was restricted to a region known for its low terrestrial heat flow where the negative temperature gradient is observed in the uppermost 400 m we have shown that the profiles are consistent with warming from the glacial mean of 10 c to the holocene mean of 7 c 14 ka ago and to 8 c in the last 150 years

climate change record in subsurface temperatures a global perspective analyses of underground temperature measurements from 358 boreholes in eastern north america central europe southern africa and australia indicate that in the 20th century the average surface temperature of earth has increased by about 0 5 degreesc and that the 20th century has been the warmest of the past five centuries the subsurface temperatures also indicate that earth s mean surface temperature has increased by about 1 0 degreesc over the past five centuries the geothermal data offer an independent confirmation of the unusual character of 20th century climate that has emerged from recent multiproxy studies

organic petrography and geochemical characterization of the upper cretaceous second white specks and upper belle fourche alloformations west central alberta analysis of local maturity anomalies abstract the second white specks is an enigmatic unconventional shale play in the western canada foreland basin wcfb this play has an inconsistent production performance that has impacted exploration and production risk preventing extensive development in this contribution geochemical properties are studied with the purpose to identify possible geochemical factors that could contribute to the production variability of this unconventional petroleum system the studied succession consists of the second white specks sws and upper belle fourche ubf alloformations which are part of the sws shale play organic petrology and rock eval pyrolysis were combined to characterize the organic matter om and assess om richness thermal maturity and hydrocarbon generation potential in the foredeep section of the basin the results show that the om richness and hydrocarbon generation potential in this area is good and comparison with other studies show that they do not exhibit major lateral variations the kerogen is marine type ii and is dominated by liptinite vitrinite inertinite macerals and solid bitumen alginite and bituminite are the most abundant macerals altered bituminite provides evidence of anaerobic bacteria degradation there is a modest contribution of inertinite that may be responsible for a dilution effect of the pyrolyzable carbon the thermal maturity indicators in this study such as vitrinite reflectance tmax and alginite uv fluorescence color indicate that the controls on thermal maturity and hydrocarbon generation are not well understood there are lateral short scale variations or maturity anomalies that require further investigation to reduce the exploration risk

late holocene lake sedimentology and climate change in southern alberta canada abstract climatic changes in southern alberta canada for the past 4000 yr are reflected in a high resolution record of lake sediment grain size the proposed mechanism for this response is that outflow discharge removes fine grained sediments but increasingly fine sediments are retained and deposited as streamflow declines at the same time coarse sediments are brought in by high discharge entering the lake the net effect of these two processes is to leave coarse clay deficient sediments during times of high streamflow and clay rich sediments during times of low flow the grain size record from pine lake reflects historic climate fluctuations as well as prehistoric fluctuations including the little ice age and the medieval warm period grain size at this site provides a simple economical and nonbiologically mediated paleoclimate proxy

summary of quaternary geology of the municipality of anchorage alaska abstract quaternary geology of the upper cook inlet region is dominated by deposits of glacier retreats that followed repeated advances from both adjacent and more distant mountains at several levels high on the mountains there are remnant glacial deposits and other features of middle or older pleistocene age late pleistocene lateral moraines along the chugach mountain front represent successively younger positions of ice retreat from the last glacial maximum as the trunk glacier retreated northeastward up the anchorage lowland cook inlet transgressed the area depositing the bootlegger cove formation and tudor road deposits the glacier then readvanced to form the latest pleistocene elmendorf moraine a prominent feature that trends across the anchorage lowland extensive alluvium was deposited both concurrently and somewhat later as cook inlet regressed mountain valleys contain 1 locally preserved moraines possibly of early holocene age 2 poorly preserved moraine remnants of older late holocene age and 3 well preserved moraines formed mainly during the little ice age glaciers still occupy large parts of the mountains the upper ends of some mountain valleys and small cirques holocene landslide deposits including those formed during the great alaska earthquake of 1964 occur throughout the area especially along bluffs containing the bootlegger cove formation

a large earthquake occurring 700 800 years ago in aialik bay southern coastal alaska a conifer forest on the shore of verdant cove an inlet of aialik bay on the southeast coast of the kenai peninsula alaska was buried by high energy beach sediments shortly after 860 50 i4c years bp the switch from ocean distal forest to cobble beach indicates a radical change in depositional environment suggestive of rapid subsidence of 1 3 5 m the presence of hemlock a tree taxon sensitive to salt water exposure and the preserved cast of a tree trunk suggest that subsidence and burial occurred rapidly by 690 60 14c years bp forest peat was accumulating atop the beach sediments burying the forest and rapid spit progradation was underway spit progradation implies land emergence or stable sea level especially in this case where the spit has a limited sediment supply we infer that subsidence of the spit ca 860 50 14c years bp was followed by slow land emergence up to the time of the 1964 ad great earthquake when the area subsided coseismically 1 4 m the sudden drowning of the buried fore

anomalously low heat flow density in eastern karelia baltic shield a possible palaeoclimatic signature abstract we report new heat flow density hfd values in seven drill holes in the kamennye lakes area in eastern karelia russia approximately at latitude 63 15 n longitude 36 10 e the investigated holes are 250 750 m deep and they intersect archaean ultrabasic serpentinites and talc carbonate rocks measured gradients range from 0 8 to 3 7 mk m 1 and the apparent hfd values from 2 4 to 11 6 mw m 2 the holes are not technically disturbed by fluid flow or any drilling effects average heat production of the rocks as analysed in the core samples of the deepest measured hole is 0 25 w m 3 but the low heat production is not a critical factor in producing the low hfd values this is due to refraction of heat as shown with 2 d conductive simulations of heat transfer in a low heat production formation surrounded by higher heat production hydrogeological disturbances can be ruled out by the presence of saline groundwater in the sections deeper than 150 400 m and low topographic variation in the area as well as peclet number estimates which suggest negligible convective heat transfer in the bedrock all the temperature profiles are curved indicating recent palaeoclimatic disturbances inversion studies with singular value decomposition techniques yielded a climatic warming of about 1 0 1 5 k which started 150 200 years ago and was preceded by a cool period which lasted about 100 years nevertheless recent climatic changes cannot explain the very low apparent hfd values but long period effects of the weichselian glaciation are sufficient to decrease the hfd values to the levels measured these effects were investigated with forward simulations and suggest that present temperature gradients in the range of 1 4 mk m 1 in the uppermost 1 km can be created by a very cold ground temperature 10 to 15 c during the glaciation time 60 11 ka ago

heat flow variations in a deep borehole near sept iles quebec canada paleoclimatic interpretation and implications for regional heat flow estimates a deep 2000m borehole in the sept iles intrusion on the north shore of the saint lawrence river in quebec canada was repeatedly logged for temperature systematic variations of the temperature gradient with depth are not correlated with the thermal conductivity we interpreted the temperature profile as follows 1 during the last glacial maximum the temperature at the base of the ice sheet was cold 5 c 2 when the region was below sea level between 10 and 5ky b p the ground surface temperature was warm 6 c 3 the average ground surface temperature dropped to 2 c at 5ky b p when the region rebounded above sea level 4 the long time averaged ground surface temperature before the last glacial maximum was 0 1 c 5 the reference heat flow 36 37mw m 2 is 4 5mw m 2 higher than estimated from the upper 1000m of the heat flow profile this interpretation can not be extrapolated to the entire region covered by the laurentide ice sheet except for extremely deep 1500m boreholes the small uncertainty 15 affecting heat flow estimates can not be eliminated

chemical and isotopic compositions of fluids at cumbal volcano colombia evidence for magmatic contribution we present chemical and isotopic data for fumarolic vapor and thermal spring discharges from cumbal volcano sw colombia in 1988 cumbal showed signs of apparent reactivation gases and steam condensates were sampled from summit fumaroles 83 375 c of cumbal in 1988 1996 and discharges from thermal springs 15 37 c on its flanks in 1995 1996 based on relative co2 total s h2s so2 and hcl contents fumarolic discharges are principally magmatic in composition fumarolic steam condensates 1993 1996 have 18o values of 11 4 to 2 5 and d values of 91 to 43 18o and d compositions indicate mixing between local meteoric and magmatic waters 3he 4he ratios in 1993 1996 samples 5 3 7 9 rcor are consistent with addition of mantle derived helium 13cco2 values for 1996 samples 6 7 to 5 0 likely indicate contribution of marine carbonate organic sediment and mantle derived co2 34sstotal compositions 4 6 to 5 6 of 1988 1996 fumarolic discharges have magmatic signatures and may reflect cycles of deposition and remobilization of native sulfur thermal waters are acid sulfate or bicarbonate in composition relative concentrations of chemical constituents of thermal waters imply that the composition of waters is controlled by absorption of magmatic volatiles into shallow ground and surface waters dilution with meteoric waters along flow paths and dissolution of host rocks 18o and d compositions are consistent with a meteoric origin of waters 34sstotal values for thermal spring gas discharges 9 6 10 5 suggest deposition of 34s depleted sulfur minerals along flow paths chemical and isotopic compositions of 1988 1995 fumarolic discharges provide evidence for input of magmatic volatiles into the cumbal hydrothermal system from 1995 to 1996 geochemical data show increasing hydrothermal signatures suggesting a decline in magmatic volatile input

ground surface temperature history in southern canada temperatures at the base of the laurentide ice sheet and during the holocene abstract we use temperature profiles from 7 deep 2000 m boreholes located in southern canada to infer ground surface temperature histories gsth during the last glacial maximum lgm and the holocene visual inspection of the heat flow and of the reduced temperature depth profiles reveals significant regional differences with some sites showing conspicuous signs of post glacial warming and other indicating only very small changes in ground surface temperature these differences are confirmed by the inversions of the temperature profiles the most prominent variations in gst are found at the sudbury ontario sites where the present ground surface temperature is high with the exception of sept iles quebec the other sites only show moderate or no variation in gst for all the sites except possibly sept iles temperatures at the base of the ice sheet during the lgm were at or slightly below the melting point of ice temperatures might have been lower a few degrees below 0 c at sept iles these results are consistent with field observations and model predictions suggesting high velocity basal flows in the ice sheet above the studied regions these new data on basal temperatures will provide better quantitative constraints on glacier flow dynamics the inversions give a chronology for the retreat of the ice sheet comparable to other proxies inversion and direct modeling show that following the ice retreat there was a warm period between 2 and 5 ka with temperatures 1 2 k higher than present the inversion yields a time for this episode 1 2 kyr more recent than that inferred by other proxies for the holocene climate optimum hco

composition of groundwaters associated with porphyry cu deposits atacama desert chile elemental and isotopic constraints on water sources and water rock reactions abstract groundwaters were collected around the spence porphyry copper deposit atacama desert northern chile to study water porphyry copper ore bodies interaction and test hypotheses regarding transport of metals through thick overburden leading to the formation of soil geochemical anomalies the deposit contains 400 mt of 1 cu and is completely buried by piedmont gravels of miocene age groundwaters were recovered from the eastern up hydraulic gradient upflow margin of the spence deposit from within the deposit and for two kilometers down flow from the deposit water table depths decrease from 90 m at the upflow margin to 30 m 1 5 km down flow groundwaters at the spence deposit are compositionally variable with those upflow of the deposit characterized by relatively low salinities 900 7000 mg l and na so42 type compositions these waters have compositions and stable isotope values similar to regional groundwaters recovered elsewhere in the atacama desert of northern chile in contrast groundwaters recovered within and down flow of the deposit range in salinity from 10 000 to 55 000 mg l one groundwater at 145 000 mg l and are dominantly na cl type waters dissolved sulfate values are however elevated compared to upflow waters and 34scdt decreases into the deposit from 4 to 2 consistent with increasing influence of sulfur derived from oxidation of sulfide minerals within the deposit the increase in salinity and conservative tracers cl br li and na and the relationship between oxygen and hydrogen isotopes suggests that in addition to water rock reactions within the deposit most of the compositional variation can be explained by groundwater mixing with perhaps a minor role for evaporation a groundwater mixing scenario implies a deeper more saline groundwater source mixing with the less saline regional groundwater flow system flow of deeper more saline groundwater along pre existing structures has important implications for geochemical exploration and metal transport models

apogean perigean signals encoded in tidal flats at the fluvio estuarine transition of glacier creek turnagain arm alaska implications for ancient tidal rhythmites turnagain arm is a macrotidal fjord style estuary glacier creek is a small glacially fed stream which enters the estuary tangentially near girdwood alaska trenches and daily sedimentation measurements were made in a mudflat along the fluvio estuarine transition of glacier creek during several summers since 2003 each year the flats appear to erode during the winter and then accrete vertically in the spring and summer in each of the years studied tidal laminae in vertically thickening and thinning laminae bundles were deposited by twice daily tides in neap spring tidal cycles in 2004 bundles of thickening and thinning laminae couplets were noted in trenches cut into the flats five laminae bundles alternated between thicker and thinner bundles corresponding to the perigean high spring and apogean low spring tides well preserved apogean perigean cycles have rarely been documented in modern tidal flat sediments at this location vertical accretion of tidal rhythmites with well developed neap spring cyclicity is possible because of the near complete removal of the flat from the previous year which creates accommodation space for vertical accretion without significant reworking macrotidal conditions no reworking by infaunal invertebrates protection from the main tidal channel by a gravel bar and protection from storm waves and fluvial erosion by a recess in the sedge marsh that surrounds the flats all aid in preservation of rhythmites during aggradation the position of the flats relative to tidal range allows for accumulation of complete spring cycles and incomplete neap cycles in the summer of 2004 apogee and perigee were closely aligned with the new and full moons resulting in successive strong perigee and apogee tides which probably aided in the accumulation of successive thick thin spring cycles encoding the apogean and perigean tidal cycle the apogean perigean signal was not observed in subsequent years

numerical simulation of permafrost evolution as a part of sedimentary basin modeling permafrost in the pliocene holocene climate history of the urengoy field in the west siberian basin present day temperature profile may be used as an important constraint for reconstruction of the thermal regime in sedimentary basin modeling this type of profile is significantly non steady state especially for basins located at high and middle latitudes however estimations of past thermal regimes are indefinite and often limited by knowledge of past glaciations and by the simple two layer model usually employed in this paper permafrost modeling was carried out as a continuation of basin modeling of the sedimentary section of urengoy field of the west siberian basin 66 n 77 e consideration of surface temperatures beginning with the triassic a refined initial temperature distribution permafrost modeling for the past 3 4 ma and use of a real lithological cross section distinguish this approach from previous studies depth and time variations in thermophysical parameters of rocks heat conductivity heat capacity unfrozen water content salt content and porosity had a considerable influence

late holocene paleoseismology of a site in the region of maximum subsidence during the 1964 mw 9 2 alaska earthquake paleoseismology of the 1964 alaska earthquake sediment archives of coseismic deformation from regions of maximum coseismic displacement act as key datasets for the development and constraint of models of surface elevation change associated with holocene great earthquakes we present new lithologic and biostratigraphic investigations of a previously thought lost core from portage at the head of turnagain arm upper cook inlet which is within the zone of maximum coseismic subsidence during the ad 1964 alaska earthquake quantitative analysis of diatoms preserved over six peat silt couplets before the ad 1964 earthquake show six phases of rapid relative sea level rise radiocarbon dates from each contact show that all six correlate with independently modelled ages of great earthquakes recorded in the prince william sound segment of the aleutian megathrust during the last 4000 years as with the other sites in the upper cook inlet there is no evidence for an earthquake between the penultimate great earthquake 880 a bp and ad 1964 in contrast to those separately recorded at kodiak island and katalla correlation of the six earthquakes at portage with those at girdwood and no evidence for additional peat silt couplets support our previous interpretation that the extra three peat silt couplets at girdwood lacking evidence of intertidal sedimentation represent local scale changes in environment rather than coseismic subsidence and short recurrence intervals of great earthquakes

new terrestrial heat flow map of europe after regional paleoclimatic correction application heat flow variations with depth in europe can be explained by a model of surface temperature changes 10 c new heat flow map of europe is based on updated database of uncorrected heat flow values to which paleoclimatic correction is applied across the continent correction is depth dependent due to a diffusive thermal transfer of the surface temperature forcing of which glacial interglacial history has the largest impact it is obvious that large part of the uncorrected heat flow values in the existing heat flow databases from wells as shallow as few hundreds of meters is underestimated this explains some very low uncorrected heat flow values 20 30 mw m2 in the shields and shallow basin areas of the craton also heat flow values in other areas including orogenic belts are likely underestimated based on the uncorrected and corrected heat flow maps using 5 km 5 km grid we have calculated average heat flow values uncorrected heat flow 56 0 mw m2 sd 20 3 mw m2 vs corrected heat flow 63 2 mw m2 sd 19 6 m wm2 and heat loss for the continental part total heat loss is 928 e09 w for the uncorrected values versus corrected 1050 e09 w

holocene glaciation of alaska and adjoining yukon territory canada abstract holocene glacial fluctuations between arctic central interior and southern maritime alaska are broadly synchronous this synchrony is evident from a review of work in 11 study areas with varying numbers of glaciers 3 100 glacier types subpolar cirque temperate valley tidewater surging and dating methodologies the pattern is temporally and spatially consistent with vegetation data and generally with climatic deteriorations culminating in the little ice age early holocene glacial advances are confirmed for 7 6 5 8 lichen ka bp at 4 of 97 glaciers in the brooks range advances also occurred by 5 85 and 5 7 ka bp at separate glacier tongues in the northern alaska range at least by 6 5 ka bp in lituya bay and possibly also in the malaspina and aleutian islands areas a sharp increase in glacier activity began by 4 4 ka bp in the arctic and glacier bay areas and by about 3 ka bp major glacier advances probably were initiated or well underway throughout alaska during holocene glacial maxima ice filled glacier and lituya bays as well as fjords of prince william sound and massive moraines buried forests in the northeastern st elias mountains area minor recession is recorded directly or implied in most of alaska about 2 ka bp or locally through the following millennium subsequently distinct but locally weak advances occurred by about 1 2 ka bp in most areas again followed by intervals of glacier recession most pervasive and ubiquitous were the little ice age advances initiated about 700 bp these generally culminated in two major advances between about 400 and 50 bp in the arctic those of a d 1600 dominated those of the late 1800s in the gulf of alaska those of the middle 1700s or late 1800s dominated large scale asynchronous advances and retreats of calving tidewater glaciers have been recorded during the twentieth century but most such movements are only indirectly related to climate

summer temperatures in the canadian rockies during the last millennium a revised record we present a significant update to a millennial summer temperature reconstruction 1073 1983 that was originally published in 1997 utilising new tree ring data predominantly picea engelmannii the reconstruction is not only better replicated but has been extended 950 1994 and is now more regionally representative calibration and verification statistics were improved with the new model explaining 53 of may august maximum temperature variation compared to the original 39 of april august mean temperatures the maximum latewood density data which are weighted more strongly in the regression model than ringwidth were processed using regional curve standardisation to capture potential centennial to millennial scale variability the reconstruction shows warm intervals comparable to twentieth century values for the first half of the eleventh century the late 1300s and early 1400s the bulk of the record however is below the 1901 1980 normals with prolonged cool periods from 1200 to 1350 and from 1450 to the late 19th century the most extreme cool period is observed to be in the 1690s these reconstructed cool periods compare well with known regional records of glacier advances between 1150 and the 1300s possibly in the early 1500s early 1700s and 1800s evidence is also presented of the influence of solar activity and volcanic events on summer temperature in the canadian rockies over the last 1 000 years although this reconstruction is regional in scope it compares well at multi decadal to centennial scales with northern hemisphere temperature proxies and at millennial scales with reconstructions that were also processed to capture longer timescale variability this coherence suggests that this series is globally important for the assessment of natural temperature variability over the last 1 000 years

mineral waters characterization in the azores archipelago portugal abstract a study of the hydrogeochemistry of more than 100 mineral waters in the azores archipelago portugal was conducted on sao miguel terceira sao jorge faial pico graciosa and flores islands about 75 of the discharges are located at sao miguel whereas the rest are more equally distributed over the other islands springs are dominant 74 but drilled wells and boiling pools comprise about 10 of the studied discharges only 2 of discharges represent hand dug wells results show a large range of chemical characteristics and diverse water types discharge temperature range between 15 c and 99 5 c median 35 c conductivity between 139 and 43 100 s cm median 906 s cm and ph between 2 2 and 7 82 median 5 78 the dominant water types are na hco 3 and na cl representing two main trends hydrothermal and marine despite a few samples of the na so 4 type relative minor and trace element contents reinforce conclusions drawn from major ion compositions that major hydrogeochemical processes are evolution of deep hydrothermal fluids adsorption of magmatic volatiles steam heating of perched aquifers and mixing of deep fluids with marine or near surface hydrothermal fluids

temperature and heat flux changes at the base of laurentide ice sheet inferred from geothermal data evidence from province of alberta canada using a previously published temperature log of the 2363 m deep borehole hunt well alberta canada and the results of its previous interpretation the new reconstructions of ground surface temperature and surface heat flux histories for the last 30 ka have been obtained two ways to adjust the timescale of geothermal reconstructions are discussed namely the traditional method based on the a priori data on thermal diffusivity value and the alternative one including the orbital tuning of the surface heat flux and the earth s insolation changes it is shown that the second approach provides better agreement between geothermal reconstructions and proxy evidences of deglaciation chronology in the studied region

heat flow variation with depth in poland evidence from equilibrium temperature logs in 2 9 km deep well torun 1 high precision temperature measurements were carried out up to a depth of 2 930 m in the 5 5 km deep well torun 1 26 years after completion of drilling the temperature log provides equilibrium thermal state information for the polish lowland at the western margin of the precambrian craton geothermal gradient calculated from the equilibrium temperature log together with estimates of thermal conductivity from net rock geophysical well logging analysis and available core measurements yields heat flow in the range 50 60 mw m2 below 2 km depth heat flow of 50 mw m2 plus 10 mw m2 generated within thick sediments and highly metamorphosed sedimentary wedge is typical for the western margin of the precambrian east european craton heat flow variations with depth can be explained by a model of surface temperature changes 10 c glaciation to holocene

the fennoscandian ice sheet during the late weichselian geothermal evidence geothermal estimates of the ground surface temperatures for the last glacial cycle in northern europe have been analysed during the middle and late weichselian 55 12 kyr bp a substantial part of this area was covered by the fennoscandian ice sheet the analysis of geothermal data allows reconstructing the limits of ice sheet extent and its basal thermal state in the late weichselian ground surface temperatures outside the ice sheet were extremely low from 7 to 17 c within the ice sheet there were both thawed and frozen zones the revealed temperature pattern is generally consistent with the modern one for ground surface temperatures in greenland which makes it possible to consider these ice sheets as analogues the anomalous climatically induced surface heat flux and orbital insolation of the earth varied consistently outside the glaciation and independently within the limits of the ice sheet

heat flow map of northern and central parts of the fennoscandian shield based on geochemical surveys of heat producing elements abstract the heat flow heat production q a relationship is a useful tool in geothermal research and it has been widely used for delineating geothermal provinces and determining characteristic parameters of heat production in the continental crust in this study a simple but rarely used technique of utilizing the heat flow heat production relationship is discussed in central and northern parts of the fennoscandian shield extensive geochemical surveys have produced 1483 samples taken from glacial till with a sampling density of 1 sample 300 km 2 heat production values determined from u th and k concentrations in these samples were used to calculate a map of heat flow density a previously determined q a relationship q 15 8 10 8 a was applied the compiled map covers all finland northern sweden and northern norway about 35 of the exposed shield area in fennoscandia heat flow density and heat production increase with decreasing geological age and correlate with granitoid types the calculated heat flow density values on the map were controlled with 12 drill hole measurements not used in calculating the applied q a regression line nine of them are from previously unpublished data from the finnish part of the shield the agreement with drill hole measurements and the geochemical estimate is reasonable although not perfect in all cases the differences can be attributed to anomalous vertical variation in heat production reliability of the applied q a plot reliability of till geochemistry in bedrock studies convective groundwater disturbances or local structural effects the calculated heat flow map can be used as a data set supplementing drill hole measurements to determine representative values of heat flow density in areas with low numbers of drill hole measurements

effect of postglacial warming seen in high precision temperature log deep into the granites in ne alberta the method how to reconstruct surface temperature history from inversions of precise temperature logs done in wells was pioneered earlier by cermak 1971 and by lachenbruch and marshall 1986 see bodri and cermak 2007 for review and list of references on the subject the method is based on the inversion of stabilized high precision deep borehole temperature logs which are in thermal equilibrium with surrounding rock deep down to some 2 km depth perturbation of the heat flow could be caused by warming since recent glaciations ending some 12 13 kyr ago in canada ritchie 1983 surface temperatures peaked in the holocene optimum 6 7 kyr ago known to be some 1 2 c warmer than recent centuries temperature level kerwin et al 1999 perturbations observed down to 0 1 0 3 km are mainly related to the climate changes of the last 1 2 centuries pollack et al 1998 bodri and cermak 2007 rath et al 2012 on large regional and continental scale all these surface temperature changes influence the subsurface heat flow the method has been applied to reconstruct timing and amplitude of surface temperature change from latest glacial to postglacial climatic history through many areas in eurasia and north america hotchkiss and ingersoll 1934 cermak 1971 kukkonen 1993 kukkonen and safanda 1996 kukkonen et al 1998 mareschal et al 1999 rolandon et al 2003 kukkonen and joeleht 2003 demezhko et al 2007 demezhko and golovanova 2007 majorowicz

evidence for the development of the andean rain shadow from a neogene isotopic record in the atacama desert chile abstract varying ages from triassic to pliocene have been proposed for the onset of hyperaridity in the atacama desert the exact timing for the initiation of hyperaridity is critical for determining potential causes which range from regional effects of global cooling to andean uplift above elevations conducive to extreme rain shadows analysis of the stable isotopic composition of lower miocene quaternary 21 0 015 ma palustrine and lacustrine carbonates in the calama basin reveals extreme changes in their oxygen and carbon isotopic composition during the miocene limestone 18 o values increased by 5 from middle to late miocene ranging from 5 5 at 12 ma to 1 at 6 ma carbon isotopic values increase by 9 over the neogene from average values of 3 at 21 ma to 3 at 12 ma and reaching a maximum of 6 at 5 ma the increase in oxygen isotopic values occurred over a time span in which the catchment area of the basin experienced significant uplift causing the 18 o value of precipitation to become more negative we attribute the shift towards higher 18 o values to enhanced evaporative enrichment both of soil water or snow prior to infiltration and within shallow lakes or wetlands prior to carbonate precipitation the large increase in 13 c values was likely caused by a transition from a vegetated landscape influenced primarily by soil respired co 2 to a landscape largely devoid of vegetation and influenced by atmospheric and volcanic co 2 isotopic values of palustrine carbonates therefore indicate that hyperaridity commenced in the calama basin during the middle to late miocene in agreement with other paleoclimatic records from the basin the cause for the onset of this climate change is thought to be due to the development of a strong andean rain shadow associated with the uplift of the andes to mean elevations 2 km

early permian sediment provenance and paleogeographic reconstructions in southeastern gondwana using detrital zircon geochronology northern perth basin western australia abstract the perth basin western australia forms part of a north trending belt of intracratonic rift basins that initiated in southeastern gondwana in the late paleozoic existing provenance studies have highlighted the dominance of proterozoic zircons derived from southerly terranes such as the albany fraser orogen leeuwin complex and more distant provinces in east antarctica with limited input from the adjacent archean western australian craton new u pb geochronology data were acquired using a sensitive high resolution ion microprobe shrimp ii on detrital zircons from lower permian formations exposed in the northeastern perth basin in contrast to previous studies archean zircons showing fine oscillatory zoning dominate the age spectra with up to 90 grains ranging between 3 0 and 2 6 ga indicating that granitic parent rocks of the adjacent craton were a major sediment source during the early permian a minor paleoproterozoic age population from the gascoyne complex of the capricorn orogen was likely transported southward and dispersed in the basin by a combination of longshore drift and tidal currents meso and neoproterozoic detritus became prominent only from the middle artinskian and may relate to the establishment of large northward flowing river systems draining the albany fraser province the prydz leeuwin belt and or the wilkes land in east antarctica this study shows that integrating depositional processes and stratigraphic evolution of sedimentary formations with provenance analysis can enhance reconstruction of dispersal pathways to and within basins

mineral water occurrence and geochemistry in the azores volcanic archipelago portugal insight from an extended database on water chemistry the occurrence and geochemistry of mineral water discharges in the azores portugal have been studied due to the volcanic nature of the archipelago mineral water discharges occur in seven of the nine islands namely at sao miguel terceira sao jorge pico faial graciosa and flores both associated to perched water and basal aquifers and mainly corresponding to springs 72 4 the majority of the 116 discharges with water geochemistry data occurs in sao miguel island 73 3 water temperature ranges between 13 2 and 99 8 c average 37 1 c being 63 8 of the samples in the dataset classified as thermal waters are mainly acid to slightly alkaline with ph values ranging between 2 1 and 7 9 average 5 85 despite the wide range of electrical conductivity values 122 53 000 s cm the median value 876 s cm suggests that in general waters in the dataset are poorly mineralized being mainly from the na hco3 and na hco3 cl types besides a few samples are from na so4 and na so4 hco3 types instead waters abstracted in basal aquifers are mainly from the na cl type principal component analysis as well as a classic hydrogeochemistry approach suggests that mineral water chemistry evolves as function of several processes as silicate weathering enhanced by water temperature not excluding mixing mechanisms between cold and hot waters regarding the so4 rich thermal waters steam heating inputs are also to be considered dilution of volcanic co2 may also influence the chemical evolution of mineral waters the influence of seawater over the mineral water chemistry in basal aquifers is shown by the much higher conductivity and cl content