the temperature dependence of hydrogen isotope fractionation between clay minerals and water evidence from a geopressured system abstract d values of water samples from two gulf coast geopressured fields vary linearly with temperature while the d values from the coexisting clays remain constant and are independent of temperature fluid how rates on the order of millimeters per year characteristic of gulf coast geopressured systems provide adequate residence time for hydrogen isotope equilibrium to be achieved between the extant porewaters and clay minerals since equilibrium is achieved these d values are used to calculate the temperature dependence of the hydrogen isotope fractionation factor between illite smectite and water clay waterh between 0 and 150 c 1000 in clay water h 45 3 10 3 t 94 7 this equation predicts values for clay waterh at 96 c which are equal to those predicted by a similar equation derived by yeh 1980 above and below 96 c this new equation predicts values which diverge from those predicted by the equation of yeh 1980 with a difference of 9 at 150 c and 25 at 0 c the possibility is raised that the very slow upward component of flow characteristic of gulf coast geopressured sediments combined with the slow downward subsidence of the clay rich sediments can result in a system which is rock dominated with respect to hydrogen

distal au deposits associated with cu au skarn mineralization in the fengshan area eastern china this work was supported by the national key research and development program china 2016yfc0600206 and the national science foundation of china 41372090 and 41573042

permo carboniferous magmatism of the northeast german basin abstract variscan continent continent collision in central europe was followed by a period of syn to late tectonic magmatism involving the extrusion of large volumes of permosilesian age volcanic rocks particularly in the northeast german basin the volcanic suite up to ca 2000 m thick comprises rhyolites acid and basic andesites and tholeiitic and alkali basalts tectono geochemical analysis in conjunction with volume calculations and petrography reveals changes in volcanic activity over time a total of five eruptive stages are recognised beginning in the stephanian and extending up into the upper rotliegend permian these include the stephanian late carboniferous andesite pre ignimbrite stage i lower rotliegend permian age explosive ignimbrite stage ii post ignimbrite stage iii late rhyolite stage iv and upper rotliegend permian age late basalt stage v in addition several volcanic centres including at least two large caldera like structures are recognised the total calculated volume for the northeast german basin volcanics is ca 48 000 km3 comprising rhyolitic rocks and ignimbrites ca 70 andesitic rocks ca 26 and basalts with cogenetic dolerites ca 4 regional variations in composition and geochemistry are related to diverse crust mantle regimes which correlate with differing positions relative to the heterogeneous basement of the variscan foredeep or within the rhenohercynian orogenic zone the crustal thickening and increasing generation depth of the mafic magmas from north to south may reflect the presence of a pre existing subduction influenced basaltic magma source

semi analytical solutions for vertically and laterally loaded piles in multilayered soil deposits in geotechnical practice it is of considerable importance to assess the behavior of vertical lateral coupled loading piles in multilayered soil deposits this study deals with a semi analytical formulation for the performance of a pile suffering from combined vertical and lateral loads the emphasis is on quantifying the mobilization of the subgrade reaction provided by the layered soil stratums in the proposed method subgrade reactions correlated with both the accumulative axial load transfer and side resistances depending upon the pile soil interaction are abstracted as a series of nonlinear springs in both vertical and lateral directions on account of this an alternative transfer matrix method is applied to characterize the pile reaction along the depth under the identified boundary conditions atop the pile meanwhile the condition of static equilibrium between two specific pile segments located at the border of soil layers is also essential on this basis validation of the solution is conducted by comparing with observations from experiments and predictions obtained from other existing methods in addition the influence of properties in shallow soil layer and the vertical load on the lateral response of the pile is also discussed the results indicate a reduction in the lateral displacement and the maximum bending moment within the pile with the increase in the shallow soil stiffness but a growth with the increase in vertical load due to the p effect

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

simulating seismic chimney structures as potential vertical migration pathways for co2 in the snohvit area sw barents sea model challenges and outcomes carbon capture and storage ccs activities at the snohvit field barents sea will involve carrying out an analysis to determine which parameters affect the migration process of co2 from the gas reservoir to what degree they do so and how sensitive these parameters are to any changes this analysis will aim to evaluate the effects of applying a broad but realistic range of reservoir fault and gas chimney properties on potential co2 leakage at various depths throughout the subsurface fluid flow might take place through parts of or the entire extent of the overburden one of the aims of the analysis is assessing the potential of co2 reaching the seabed using the snohvit gas reservoir and overburden in the barents sea a series of geological models were built using seismic and well log data we then performed numerical simulations of co2 migration in focused fluid flow structures identification of potential migration pathways and their extent such as gas chimneys and faults and their incorporation into these models and simulations will provide a realistic insight into the migration potential of co2 in the simulations the co2 is injected over a 20 year period at a rate of 0 7 mt year and migration is allowed to take place over a 2000 year time frame for domains of approximately 21 km2 for the caprock fault models 24 km2 for the realistic gas chimney models and 35 km2 for the generic gas chimney models in a layered sedimentary succession the total mass of co2 injected in the reservoir during the 20 year injection period is 14 mt there is a strong interaction between the various parameters but the parameter that had the most influence on the co2 migration process was probably the permeability of the reservoirs especially the average permeability k also for the faulted caprock scenarios it should be noted that at near surface depths the permeability of 765 md is already adequate for a good co2 flow at the chimney top level 600 m however a further increase in permeability has an additional effect on improving co2 flow overall considering the slow upward migration velocity of the plume this geological setup can be regarded as a suitable storage site

formation of a paleothermal anomaly and disseminated gold deposits associated with the bingham canyon porphyry cu au mo system utah the thermal history of the oquirrh mountains utah indicates that hydrothermal fluids associated with emplacement of the 37 ma bingham canyon porphyry cu au mo deposit extended at least 10 km north of the bingham pit an associated paleothermal anomaly enclosed the barneys canyon and melco disseminated gold deposits and several smaller gold deposits between them previous studies have shown the barneys canyon deposit is near the outer limit of an irregular distal au as geochemical halo about 3 km beyond an intermediate pb zn halo and 7 km beyond a proximal pyrite halo centered on the bingham porphyry copper deposit the melco deposit also lies near the outer limit of the au as halo analysis of several geothermometers from samples collected up to 22 km north of the bingham canyon porphyry cu au mo deposit indicate that most sedimentary rocks of the oquirrh mountains including those at the gold deposits have not been regionally heated beyond the oil window less than about 150 c for geologically reasonable heating durations the maximum sustained temperature at melco 6 km north of the bingham pit and at barneys canyon 7 5 km north of the pit was between 100 c and 140 c as indicated by combinations of conodont color alteration indices of 1 5 to 2 mean random solid bitumen reflectance of about 1 0 percent lack of annealing of zircon fission tracks and partial to complete annealing of apatite fission tracks the pattern of reset apatite fission track ages indicates that the gold deposits are located approximately on the 120 c isotherm of the 37 ma paleothermal anomaly assuming a heating duration of about 106 years the conodont data further constrain the duration of heating to between 5 104 and 106 years at approximately 120 c the 18o of quartzite host rocks generally increases from about 12 6 per mil at the porphyry to about 15 8 per mil approximately 11 km from the bingham deposit this change reflects interaction of interstitial clays in the quartzite with circulating meteoric water related to the bingham canyon porphyry system the 18o and 13c values of limestone vary with respect to degree of recrystallization and proximity to open fractures recrystallized limestone at the melco and barneys canyon gold deposits has the highest 18o values about 30 whereas limestone adjacent to the porphyry copper deposit has the lowest values about 10 the high 18o values for the recrystallized limestone at barneys canyon and melco strongly suggest that mineralization was related to low temperature fluids with exceptionally high 18oh2o values such as could be derived from water in a crater lake of an active volcano the age of formation of the gold deposits has been interpreted to range from jurassic to eocene the mineralized rocks at the barneys canyon and melco deposits are likely the same age as the geochemically similar deposits that are present in north striking late faults that cut the bingham canyon porphyry the patterns of apatite and zircon fission track data conodont color alteration indices solid bitumen reflectivity stable isotope data and mineral zoning are consistent with the gold deposits being genetically related to formation of the 37 ma bingham porphyry deposit we interpret the disseminated gold mineralization to be related to collapse of the bingham canyon hydrothermal system in which isotopically heavy oxidizing acidic waters possibly from an internally draining acidic crater lake mixed with and were entrained into reduced gold bearing meteoric water fluids in the collapsing main stage hydrothermal system most of this fluid mixing and cooling was probably located close to the hydrologic interface between the sedimentary basement rocks and overlying volcanic rocks

ikaite pseudomorphs in neoproterozoic dalradian slates record earth s coldest metamorphism calcite pseudomorphs have replaced euhedral ikaite caco 3 6h 2 o porphyroblasts in dalradian calcareous slates and metadolostones of western scotland with a volume decrease of at least 47 porphyroblast fabric relationships indicate that the initial growth of ikaite post dates a penetrative tectonic fabric developed during upright folding this is the first reported occurrence of metamorphic ikaite porphyroblasts and points towards growth within the slates during an ultra low temperature metamorphism with an exceptionally low geothermal gradient this event is associated with the penetration of long lived and extreme permafrost deep into subaerially exposed bedrock during neoproterozoic glaciation the presence of the well preserved pseudomorphs within the easdale slates of the argyll group implies that a neoproterozoic orogenic unconformity exists above the stratigraphic position of these rocks

plate and intraplate processes of hercynian europe during the late paleozoic abstract it is speculated that until late carboniferous time the region of hercynian europe was occupied by an elongated island arc system underlain by a segment of continental crust in the upper carboniferous two subduction zones are assumed to have extended from the north and south beneath hercynian europe an extensive zone of hot partially molten upper mantle lay above and between these and diapiric uprise of portions of this material led to separation of mafic magmas widespread partial melting in the lower and middle crust high temperature low pressure metamorphism in crustal rocks and regional uplift and extension of the crust as indicated by intermontane troughs and their associated volcanic rocks in visean to westphalian time hercynian europe collided with both the large neighbouring plates north america europe and africa during these diachronous collisions and owing to reduced rigidity of the relatively hot island arc crust the irregular continental margins of the larger and thicker continental plates induced oroclinal bending of hercynian europe after the collision processes had been terminated processes of upper mantle activity continued causing further crustal uplift and even enhanced crustal extension for several tens of million years into the lower permian decline of the upper mantle activity beneath hercynian europe is indicated by crustal subsidence and formation of a peneplain in permian time followed by the upper permian transgression of both the zechstein sea and the tethys sea which mark the end of the hercynian geodynamic cycle

carbon dioxide injection and associated hydraulic fracturing of reservoir formations the storage potential of subsurface geological systems makes them viable candidates for long term disposal of significant quantities of co2 the geo mechanical responses of these systems as a result of injection processes as well as the protracted storage of co2 are aspects that require sufficient understanding a hypothetical model has been developed that conceptualises a typical well reservoir system comprising an injection well where the fluid co2 is introduced and a production abandoned well sited at a distant location this was accomplished by adopting a numerical methodology discrete element method specifically designed to investigate the geo mechanical phenomena whereby the various processes are monitored at the inter particle scale fracturing events were simulated in addition the influence of certain operating variables such as injection flow rate and fluid pressure was studied with particular interest in the nature of occurring fractures and trend of propagation the pattern and magnitude of pressure build up at the well vicinity pressure distribution between well regions and pore velocity distribution between well regions modelling results generally show an initiation of fracturing caused by tensile failure of the rock material at the region of fluid injection however fracturing caused by shear failure becomes more dominant at the later stage of injection furthermore isolated fracturing events were observed to occur at the production abandoned wells that were not propagated from the injection point this highlights the potential of co2 introduced through an injection well which could be used to enhance oil gas recovery at a distant production well the rate and magnitude of fracture development are directly influenced by the fluid injection rate likewise the magnitude of pressure build up is greatly affected by the fluid injection rate and the distance from the point of injection the dem modelling technique illustrated provides an effective procedure that allows for more specific investigations of geo mechanical mechanisms occurring at subsurface systems the application of this methodology to the injection and storage of co2 facilitates the understanding of the fracturing phenomenon as well as the various factors governing the process

3d structural model of the polish basin abstract a 3d structural modelling of the permian mesozoic polish basin was performed in order to understand its structural and sedimentary evolution which led to basin maturation permian cretaceous and its tectonic inversion late cretaceous paleogene the model is built on the present day structure of the basin and comprises 13 horizons within the permian to quaternary rocks the analysis is based on 3d depth views and thickness maps the results image the basin scale symmetry the perennial localization of the nw se oriented basin axis the salt movements due to tectonics and or burial and the transverse segmentation of the polish basin from these observations we deduce that salt structures are correlated to the main faults and tectonic events from the model analysis we interpret the stress conditions the timing and the geometry of the tectonic inversion of the polish basin into a nw se oriented central horst mid polish swell bordered by two lateral troughs emphasis is placed on the zechstein salt considering its movements during the mesozoic sedimentation and its decoupling effect during the tectonic inversion moreover we point to the structural control of the paleozoic basement and the crustal architecture teisseyre tornquist zone on the geometry of the polish basin and the mid polish swell

thermal effects of zechstein salt and the early to middle jurassic hydrothermal event in the central polish basin deep gas potential in the polish basin may factor significantly in european geopolitics and thermal effects can influence that outcome there and elsewhere deep 3 km 9843 ft well data from the kujawy area of the central polish basin reveal average geothermal gradient 36c km thermal conductivity of mesozoic strata k 2 29 w m k and present day heat flow q 82 4 mw m2 that is 3 less than that obtained using the entire borehole the extrapolated surface temperature 6 2c is in good agreement with temperatures during the weichselian glaciation the thermal conductivity of the upper permian zechstein 4 89 w m k is in good agreement with values from the north sea and northern germany steady state heat flow theory one dimensional 1 d predicts present day temperature 199c at the base of zechstein cap rock at 6 km 19 685 ft depth in kujawy this is reduced just more than 10c by low zechstein thermal gradients 16 8c km because of thermal refraction two dimensional and three dimensional models of zechstein salt pillows can significantly negate this cooling effect however such effects appear absent in the kujawy wells studied a widespread early to middle jurassic 195 175 ma hydrothermal event appears to have reached maximum in the kujawy area a 455c paleotemperature at 7 km 22 966 ft depth carboniferous is predicted by 1 d conductive heat transfer however geologic evidence does not support this result the discrepancy is reconciled by convective heat transfer with upward fluid flow 3 3 10 10 m s 10 8 10 10 ft s resulting in a maximum paleotemperature of 273c at 7 km 22 966 ft depth despite a paleoheat flow of 142 mw m2 the trend of intensity of the hydrothermal event correlates with the present day heat flow trend hydrothermal event sites are subparallel to the major northwest southeast structural and regional heat flow trend whereas other sites as close as 14 km 45 932 ft and without hydrothermal event are not the decay of the hydrothermal event is consistent with localized cylindrical plumes 10 km 32 808 ft radius that cool by conduction results suggest a long term 185 m y structural control on heat flow linear regression to vitrinite paleotemperatures yields a 185 ma jurassic surface temperature of approximately 21 3c that is approximately 13c higher than the present day temperature for warsaw poland the duration of maximum reservoir and source rock paleotemperature 50 m y is contrary to the kinetics of nitrogen and co2 producing wells equilibrium thermodynamics predicts approximately 60 methane for present day kujawy reservoirs with considerable uncertainty that should be removed by anticipated new deep drilling

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

geology and geochemistry of the deep star gold deposit carlin trend nevada deep star is a high grade carlin type gold deposit located in the northern part of the carlin trend the deposit averages 34 0 g t au and by year end 2000 had produced 37 8 t 1 217 000 oz gold with a remaining reserve of 16 0 t 513 698 oz gold the deposit is primarily hosted in brecciated calc silicate rocks of the devonian popovich formation with a minor amount of gold in the jurassic goldstrike diorite intrusion of the syn and postore deep star rhyolite constrains the age of the mineralization the postore rhyolite is compositionally and mineralogically similar to the synore dike and yielded an average 40ar 39ar isochron age of 38 3 ma eocene rhyolite dikes intruded active dilatant north to northeast striking faults and or fractures providing an important age constraint on the local stress regime at deep star during mineralization essentially horizontal west northwest directed eocene extension 291 is consistent with dextral normal oblique slip observed on north south striking east dipping portions of the gen post fault system and dilation and sinistral shear on dike filled northeast striking structures a right stepping releasing bend in the deep star fault at its intersection with northwest and north northwest striking subsidiary structures created a deep tapping dilatant conduit for gold bearing hydrothermal fluids five stages of hydrothermal alteration are present at deep star stages 1 and 2 are related to thermal metamorphism metasomatism and possibly retrograde alteration associated with intrusion of the goldstrike stock stage 3 consists of preore quartz carbonate alteration the carbonate minerals are zoned both laterally and vertically with dolomite as the dominant mineral closest to ore stage 3 overlaps with stage 4 quartz kaolinite alteration associated with the introduction of gold and is therefore interpreted to be part of the eocene mineralizing event gold is hosted in as rich rims on marcasite and pyrite within a kaolinite and quartz matrix postore stage 5 is dominated by calcite with lesser siderite and barite a three dimensional geochemical model of the deep star deposit and its environs reveals that carlin type systems may have a geochemical expression involving a much broader suite of elements than previously recognized elements with distribution patterns considered to be related to the mineralizing event include ag as au ba bi ca cd co cu fe hg mg mo mn ni p pb s sb se te tl u v w and zn the multielement anomaly associated with the deep star deposit is best described as a vertical plume that is 1 focused between the deep star and post faults below the deposit 2 present in the footwall of the deep star fault and the deep star post fault corridor at the level of the deposit and 3 broadly dispersed above and to the west of the deposit under the influence of northeast and northwest trending structural fabrics most closely associated with gold deposition are enrichments in as sb hg tl ag and zn within a halo of ca mg ba and sr depletion the elements fe mn co ni and p are most elevated in the immediate hanging wall of the deep star fault and above the deposit in a region where secondary carbonate veins ankerite kutnahorite and mn rich dolomite open space filling carbonate minerals siderite calcite have been observed some lateral zonation is evident at levels above the deposit with increases of pb and bi on its eastern margin and more mo u v and w west of the deposit isotopic analyses of kaolinite are interpreted to indicate that gold mineralizing fluids originated from either a magmatic or possibly a deep metamorphic source fluids range from near the magmatic water field for those near the center of the deep star orebody along a mixing path toward exchanged mid tertiary meteoric water as represented by the fluids near the eastern orebody margin

crustal memory and basin evolution in the central european basin system new insights from a 3d structural model abstract the central european basin system cebs is composed of a series of subbasins the largest of which are 1 the norwegian danish basin 2 the north german basin extending westward into the southern north sea and 3 the polish basin a 3d structural model of the cebs is presented which integrates the thickness of the crust below the permian and five layers representing the permian cenozoic sediments structural interpretations derived from the 3d model and from backstripping are discussed with respect to published seismic data the analysis of structural relationships across the cebs suggests that basin evolution was controlled to a large degree by the presence of major zones of crustal weakness the nw se striking tornquist zone the ringkobing fyn high rfh and the elbe fault system efs provided the borders for the large permo mesozoic basins which developed along axes parallel to these fault systems the tornquist zone as the most prominent of these zones limited the area affected by permian cenozoic subsidence to the north movements along the tornquist zone the margins of the ringkobing fyn high and the elbe fault system could have influenced basin initiation thermal destabilization of the crust between the major nw se striking fault systems however was a second factor controlling the initiation and subsidence in the permo mesozoic basins in the triassic a change of the regional stress field caused the formation of large grabens central graben horn graben gluckstadt graben perpendicular to the tornquist zone the ringkobing fyn high and the elbe fault system the resulting subsidence pattern can be explained by a superposition of declining thermal subsidence and regional extension this led to a dissection of the ringkobing fyn high resulting in offsets of the older nw se elements by the younger n s elements in the late cretaceous the nw se elements were reactivated during compression the direction of which was such that it did not favour inversion of n s elements a distinct change in subsidence controlling factors led to a shift of the main depocentre to the central north sea in the cenozoic in this last phase n s striking structures in the north sea and nw se striking structures in the netherlands are reactivated as subsidence areas which are in line with the direction of present maximum compression the moho topography below the cebs varies over a wide range below the n s trending cenozoic depocentre in the north sea the crust is only 20 km thick compared to about 30 km below the largest part of the cebs the crust is up to 40 km thick below the ringkobing fyn high and up to 45 km along the teisseyre tornquist zone crustal thickness gradients are present across the tornquist zone and across the borders of the ringkobing fyn high but not across the elbe fault system the n s striking structural elements are generally underlain by a thinner crust than the other parts of the cebs the main fault systems in the permian to cenozoic sediment fill of the cebs are located above zones in the deeper crust across which a change in geophysical properties as p wave velocities or gravimetric response is observed this indicates that these structures served as templates in the crustal memory and that the prerift configuration of the continental crust is a major controlling factor for the subsequent basin evolution

the impact of diagenetic fluid rock reactions on rotliegend sandstone composition and petrophysical properties altmark area central germany in the framework of the german r d joint project clean co2 large scale enhanced gas recovery in the altmark natural gas field rotliegend reservoir sandstones of the altensalzwedel block in the altmark area saxony anhalt central germany have been studied to characterise litho and diagenetic facies mineral content geochemical composition and petrophysical properties these sands have been deposited in a playa environment dominated by aeolian dunes dry to wet sand flats and fluvial channel fills the sediments exhibit distinct mineralogical geochemical and petrophysical features related to litho and diagenetic facies types in sandstones of the damp to wet sandflats their pristine red colours are preserved and porosity and permeability are only low rocks of the aeolian environment and most of the channel fill deposits are preferentially bleached and exhibit moderate to high porosity and permeability although geochemical element whole rock content in these rocks is very similar element correlations are different variations in porosity and permeability are mainly due to calcite and anhydrite dissolution and differences in clay coatings with fe bearing illitic chloritic composition exposed to the pore space moreover mineral dissolution patterns as well as compositions of clays and carbonate and morphotypes of authigenic minerals chlorite illite are different in red and bleached rocks comparison of the geochemical composition and mineralogical features of diagenetically altered sandstones and samples exposed to co2 bearing fluids in laboratory batch experiments exhibit similar character experiments prove an increase in wettability and water binding capacity during co2 impact

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

thermal conductivity and radiogenic heat production of sedimentary and magmatic rocks in the northeast german basin thermal rock properties were determined for the northeast german basin a subbasin of the southern permian basin in europe the new thermal data provide new aspects for the determination of heat flow and for hydrocarbon and geothermal resource evaluation in the basin thermal conductivity was measured on drill core samples using the optical scanning method values for permian and pre permian clastic rocks are variable 2 3 4 8 w m k because of different depositional environments compaction and cementation reflected in lithology permian carboniferous igneous rocks show lowest thermal conductivity in basalts 2 2 w m k and highest 3 1 w m k in granitoids anisotropy of thermal conductivity in all rocks is low formation thermal conductivity was determined by upscaling the values determined for single lithotypes radiogenic heat production was determined on drill cores for the upper paleozoic sediments and igneous rocks for the younger formations without sample control a well log approach was used the heat production of sedimentary rocks is lowest 0 4 w m3 in the permian zechstein salt and anhydrite and highest 2 1 w m3 in the permian rotliegende clastic rocks heat production of the permian carboniferous rhyolites and granitoids is on the order of 2 6 3 8 w m3 and heat production of andesites and basaltoids is on the order of 0 9 1 9 and 0 1 0 7 w m3 respectively the contribution to surface heat flow by these up to 2 km 1 2 mi thick igneous complexes amounts to 7 mw m2 at a maximum on the same order is the total heat budget provided by the supra permian sedimentary succession in the basin

lateral resistance and deflection of rigid walls and piles in layered soils the ultimate lateral resistance and the lateral deflection at working loads of rigid vertical walls and piles with a free head subjected to horizontal load and embedded in two layered soils of sand and clay have been investigated part 1 deals with the behaviour of rigid walls and the analyses are compared with the results of model wall tests in layered soils part 2 treats the behaviour of rigid piles and the analyses are compared with the results of model tests on piles and pile groups in layered soils and some field case records

geology and geochemistry of the barneys canyon gold deposit utah barneys canyon is a sediment hosted disseminated gold deposit located 7 km from the large gold rich bingham porphyry copper deposit host rocks for gold mineralization are the permian park city dolomite and siltstone and the kirkman diamond creek sandstone the gold deposit is approximately 430 m long 370 m wide up to 90 m thick and contains 8 5 million metric tons t of reserves averaging 1 6 g t gold intrusive igneous rocks are conspicuously absent the gold deposit is located on the northern flank of the northeast trending copperton anticline an overturned box fold a small east striking south dipping thrust fault the barneys canyon thrust fault with 200 m displacement repeats the park city formation and north south striking steep normal faults form a graben in which the gold deposit is located the barneys canyon thrust fault predates mineralization and the phosphate normal fault postdates mineralization alteration of the host rocks is similar to other sediment hosted disseminated gold deposits but at lower alteration mineral abundances kaolinite and illite comprise less than 10 percent of the altered rock silicification is minor barite is rare and pyrite and marcasite are common but not abundant trace as sb hg tl and ba show pronounced increase k ar age determinations on vein illite from ore grade 1 5 ppm gold bedding plane gougelike material yield jurassic ages fluid inclusion measurements from barite and jasperoid show a mean salinity of 1 7 wt percent nacl equiv and homogenization temperatures of 130 degrees to 393 degrees c with weak modes at 350 and 230 degrees c suggesting that two fluids have interacted with rocks at barneys canyon kaolinite bearing assemblages formed below 280 degrees c pressure correction at hydrostatic pressure is 12 degrees c fluid inclusion measurements geochronology structure trace elements and distance from bingham are inconsistent with genesis of the barneys canyon deposit as part of the bingham porphyry copper system it is unlikely that genesis of the barneys canyon gold deposit involved igneous activity

basin evolution of the northern part of the northeast german basin insights from a 3d structural model abstract a 3d structural model for the entire southwestern baltic sea and the adjacent onshore areas was created with the purpose to analyse the structural framework and the sediment distribution in the area the model was compiled with information from several geological time isochore maps and digital depth maps from the area and consists of six post rotliegend successions the upper permian zechstein lower triassic middle triassic upper triassic jurassic cretaceous and cenozoic this structural model was the basis for a 3d backstripping approach considering salt flow as a consequence of spatially changing overburden load distribution isostatic rebound and sedimentary compaction for each backstripping step in order to reconstruct the subsidence history in the region this method allows determination of the amount of tectonic subsidence or uplifting as a consequence of the regional stress field acting on the basin and was followed by a correlation with periods of active salt movement in general the successions above the highly deformed zechstein evaporites reveal a thickening trend towards the gluckstadt graben which also experienced the highest amount of tectonic subsidence during the mesozoic and cenozoic two periods of accelerating salt movement in the area has been correlated with the e w directed extension during the late triassic early jurassic and later by the late cretaceous early cenozoic inversion suggesting that the regional stress field plays a key role in halokinesis the final part of this work dealt with a neotectonic forward modelling in an attempt to predict the future topography when the system is in a tectonic equilibrium the result reveals that many of the salt structures in the region are still active and that future coastline will run with a wnw ese trend arguing that the compressional stresses related to the alpine collision are the prime factor for the present day landscape evolution

tomographic p wave velocity and vertical velocity gradient structure across the geothermal site gros schonebeck ne german basin relationship to lithology salt tectonics and thermal regime 1 seismic wide angle data were collected along a 40 km long profile centered at the geothermal research well grsk 3 90 in the northeast german basin tomographic inversion of travel time data provided a velocity and a vertical velocity gradient model indicative of cenozoic to pre permian sediments wide angle reflections are modeled and interpreted as top zechstein and top pre permian changes in velocity gradients are interpreted as the transition from mechanical to chemical compaction at 2 3 km depth and localized salt structures are imaged suggesting a previously unknown salt pillow in the southern part of the seismic profile the zechstein salt shows decreased velocities in the adjacent salt pillows compared to the salt lows which is confirmed by sonic log data this decrease in velocity could be explained by the mobilization of less dense salt which moved and formed the salt pillows whereas the denser salt remained in place at the salt lows we interpret a narrow subvertical low velocity zone under the salt pillow at grsk 3 90 as a fault in the deep permian to pre permian this wnw ese trending fault influenced the location of the salt tectonics and led to the formation of a fault bounded graben in the rotliegend sandstones with optimal mechanical conditions for geothermal production thermal modeling showed that salt pillows are related to chimney effects a decrease in temperature and increasing velocity the assumed variations in salt lithology density and strain must thus be even higher to compensate for the temperature effect

evolution of the northeast german basin inferences from a 3d structural model and subsidence analysis abstract a 3d structural model of the northeast german basin was evaluated with special emphasis on its evolution as an intracontinental depression the study includes investigations on subsidence history and structural setting of the basin thickness evolution and calculated tectonic subsidence volumes of permian to quaternary sediments in the northeast german basin indicate that the subsidence history was related to five stages of basin evolution which differ in their subsidence mechanisms for the initial rift phase in the late carboniferous to early permian a dominant thermal event and subordinate horizontal stresses were indicated by thickness variation evolution and by structural evidence the main part of basin subsidence occurred in a nw se oriented basin in the subsequent phase of thermal relaxation with maximum subsidence from early permian rotliegend to middle triassic muschelkalk from middle triassic the thermal subsidence pattern was superposed by further tectonic events in the middle triassic regional extension led to a reconfiguration of the southern part of the basin where new nne ssw trending troughs rheinsberg and gifhorn troughs developed in the jurassic the northwestern part of the basin was uplifted while in the south the keuper subsiding areas continued to sink and nw se trending depressions related to salt margins became important differentiation continued into cretaceous times when regional compression caused uplift of the southeastern part of the basin and basin margins a final subsidence phase occurred in the cenozoic this was accompanied by intensive salt movement recent basin configuration reflects the superposition of structural elements resulting from different evolution stages the main structural characteristics of the basin are 1 a vertical tectonic zonation in a pre zechstein succession which lacks significant internal structures and a strongly deformed post zechstein succession which was decoupled due to the thick zechstein salt and 2 a marked asymmetry of the basin with a shallow northern slope and a steep bounding fault at the southern margin elbe fault system the northwestern part of the basin shows the structural properties of an intracratonic sag basin with persisting subsidence and with minor salt mobilisation in contrast initial structures in the southeastern part are strongly overprinted by younger tectonic events including middle triassic to jurassic extension late cretaceous inversion and late to post cretaceous salt movements tectonic elements that deform the whole sedimentary succession are restricted to the basin s southern eastern and northeastern margins where salt thickness decreases combined volumetric and backstripping investigations show that 2 3 of the total subsidence was induced by the sediment load and 1 3 was caused by tectonics the tectonic subsidence history varies laterally across the basin while tectonic subsidence curves in the northwestern part of the basin show fast subsidence during the permian and early triassic decreasing exponentially with time subsidence curves in the southeastern part indicate repeated tectonic activity however the tectonic subsidence volume created during permian to late triassic is significantly higher than the tectonic subsidence during younger phases of basin history

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

an integrative geothermal resource assessment study for the siliciclastic granite wash unit northwestern alberta canada this study explores the siliciclastic granite wash unit in northwestern alberta as a potential geothermal reservoir the approach covers regional 3d structural geological modelling of a 90 km 70 km area based on well log and legacy 2d seismic data the fault strike was interpreted from lineaments which were identified with the refined trend surface analysis method the stress state of the granite wash reservoirs was determined by an integrated approach of 3d fault modelling stress ratio definition based on frictional constraints and slip tendency analysis the results show that the best site for a geothermal application is located in the southwestern study area where the highest temperatures above 70 c coincide with the largest thickness above 20 m and zones of elevated porosity and permeability the integrated stress analysis indicates an in situ stress regime from normal to strike slip faulting maintaining a non critically stressed reservoir or faults therein assuming a friction coefficient of 0 7 the granite wash reservoirs could be used for heating of greenhouses domestic warm water provision and district heating

fe oxides in jasperoids from two gold districts in nevada characterization geochemistry and u th he dating abstract this study examines the whole rock geochemistry fe oxide texture and crystal morphology and fe oxide u th he date variation of jasperoids as well as the relationships between these characteristics in order to evaluate jasperoids as an indicator for gold mineralization jasperoid samples with a range of textures appearances and expected gold concentrations were collected from two gold districts in nevada the northern carlin trend gold quarry mine and the battle mountain district marigold mine battle mountain prospect in our jasperoid samples whole rock concentrations of au are positively correlated with as ag pb sb u w and tl the following fe oxide textures are associated with anomalous gold concentrations disseminated submicron crystals feathery and acicular crystal morphologies concentric zonation from hematite to goethite and botryoidal textures calculated closure temperatures for the u th he system in observed jasperoid fe oxide morphologies within our dataset range from 26 to 136 c indicating variable susceptibility to he diffusion at near surface conditions fe oxide u th he dates range from 29 4 0 5 ma to 0 11 0 01 ma displaying intra and intersample variation we attribute the date variation to multiple factors including he implantation parent isotope exchange and he loss through closure temperature sensitivity and alpha ejection the intra and intersample variation within the fe oxide u th he dates limits our ability to make geologic interpretations our case study identifies important limitations of the u th he method in jasperoids and provides insight on how he date variation might be avoided in future studies

subsurface thermal conductivity assessment in calabria southern italy a regional case study determining the suitability of a local area at a regional or local scale for the geothermal application of low enthalpy systems requires the knowledge of rock thermal conductivity values to evaluate the possibility of low enthalpy heat exchange a digital cartographic tool is also needed to synthesize the thermal properties of the underground this tool should be easily accessible and upgradeable and thus suitable for territorial planning and environmental control in order to address these key issues a methodological approach was developed within the framework of the national vigor project dedicated to evaluating the geothermal potential in southern italy in this paper the region of calabria was selected as a case study around 70 samples that were representative of the main geological formations were collected from all over the area thermal property tests were carried out both in dry and wet conditions using a thermal device in accordance with the modified transient plane source method the thermal conductivity values were then compared with data from the international literature in order to consider the influence of the entire stratigraphic sequence on the thermal conductivity parameters a geostatistical analysis of the available lithostratigraphic data was performed using the matlab toolbox modalstrata specially developed for this purpose a comprehensive geothermal subsurface characterization of calabria was thus obtained

sensitivity of 3d thermal models to the choice of boundary conditions and thermal properties a case study for the area of brandenburg ne german basin based on newly available data of both the structural setting and thermal properties we compare 3d thermal models for the area of brandenburg located in the northeast german basin to assess the sensitivity of our model results the structural complexity of the basin fill is given by the configuration of the zechstein salt with salt diapirs and salt pillows this special configuration is very relevant for the thermal calculations because salt has a distinctly higher thermal conductivity than other sediments we calculate the temperature using a femethod to solve the steady state heat conduction equation in 3d based on this approach we evaluate the sensitivity of the steady state conductive thermal field with respect to different lithospheric configurations and to the assigned thermal properties we compare three different thermal models a a crustal scale model including a homogeneous crust b a new lithosphere scale model including a differentiated crust and c a crustal scale model with a stepwise variation of measured thermal properties the comparison with measured temperatures from different structural locations of the basin shows a good fit to the temperature predictions for the first two models whereas the third model is distinctly colder this indicates that effective thermal conductivities may be different from values determined by measurements on rock samples the results suggest that conduction is the main heat transport mechanism in the brandenburg area

thermal modelling of the larderello geothermal field tuscany italy we present a 3 d thermal model of the larderello geothermal field tuscany to evaluate 1 the extent and contribution of the heat transfer mechanisms conduction vs convection at the intermediate upper crust levels 2 the variability of the heat and mass fluxes entering from below and 3 the crucial role of the formation permeability the model composed by three main layers considers the upper 10 km of the crust to better constrain the simulations with experimental data from borehole fluid inclusion studies and hypocentral distributions several sets of simulations were carried out with different bottom boundary temperatures and different formation permeabilities for the two deeper layers the results indicate that the present temperature t and pressure distributions in the larderello field require deep reservoir rocks with higher permeability than the overlying capping units and underlying intermediate crust permeability values of 1 mdarcy for the reservoir rocks are enough to allow fluid convection if the temperature at 10 km depth is as high as 500 50 c the presence of localized zones with formation permeability 50 100 times higher than the surrounding rocks strongly favours the migration of over pressurized fluids which episodically break through the overburden feeding the presently exploited geothermal fields

geomechanical model for the post variscan evolution of the permocarboniferous mesozoic basins in northeast germany abstract the permocarboniferous basins in northeast germany formed on the heterogeneous and eroded parts of the variscan orogene and its deformed northern foreland transtensional tectonic movements and thermal re equilibration lead to medium scale crustal fragmentation fast subsidence rates and regional emplacement of large amounts of mostly acidic volcanics the later basin formation and differentiation was triggered by reversals of the large scale stress field and reactivation of prominent zones of weakness like the elbe fault system and the rhenohercynian saxothuringian boundary that separate different variscan basement domains in the area the geomechanical behaviour of the latter plays an important role for the geodynamic evolution of the medium to large scale structural units which we can observe today in three dimensions on structural maps geophysical recordings and digital models this study concentrates on an area that comprises the southern northeast german basin the saale basin the flechtingen high the harz mountains high and the subhercynian basin the presented data include re evaluations of special geological and structural maps the most recent interpretation of the dekorp basin 9601 seismic profile and observations of exposed rock sections in northeast germany on the basis of different structural inventories and different basement properties we distinguish two structural units to the south and one structural unit to the north of the elbe fault system for each unit we propose a geomechanical model of basin formation and basin inversion and show that the rhenohercynian fold and thrust belt domain is deformed in a thin skinned manner while the mid german crystalline rise domain which is the western part of the saxothuringian zone rather shows a thick skinned deformation pattern the geomechanical model for the unit north to the elbe fault system takes account to the fact that the base of the zechstein beneath the present northeast german basin shows hardly any evidence for brittle deformation which indicates a relative stable basement our geomechanical model suggests that the permocarboniferous deposits may have contributed to the structural stiffness by covering small to medium scale structures of the upper parts of the brittle basement it is further suggested that the pre zechstein successions underneath the present northeast german basin were possibly strengthening during the cretaceous basin inversion which resulted in stress transfer to the long lived master faults as indicated for example by the shape of the salt domes in the vicinity of the latter faults contrary to this post zechstein successions deformed in a different and rather complex way that was strongly biased by intensive salt tectonic movements

3d lithosphere scale density model of the central european basin system and adjacent areas abstract to analyze the first order structural features characterizing the crust and the lithospheric mantle below the central european basin system and adjacent areas a new lithosphere scale 3d structural density model has been derived that integrates published knowledge with 3d gravity modeling with this study we aim to integrate previous results on sub domains of the study area and regional results of limited resolution in conjunction with 3d gravity analysis to derive the configuration of the lower crust and lithospheric mantle that is consistent with the known density distribution of the sediment fill and with observed deep seismic data as well as with observed gravity the derived 3d density model resolves the internal configuration of the crystalline crust below the central european basin system and adjacent areas at the regional scale and shows that the crystalline crust is characterized by a layered structure the upper to middle crystalline crust is characterized by relatively low seismic p wave velocities and densities it shows strong variations in thickness across the study area that partly correlate spatially with the inherited segmentation in response to crustal amalgamation this upper to middle crystalline crust is underlain by a continuous high density high velocity lower crustal layer locally more than 30 km thick beneath the east european craton and generally decreasing in thickness from the older to the younger tectonic domains though the thickness of this high density lower crust is generally small below the permo cenozoic central european basin system it can reach locally more than 18 km below the northeast german and the norwegian danish basins the derived depth to the lithosphere asthenosphere boundary confirms previously proposed geometries and is up to 230 km deep beneath the precambrian domain but less than 100 km deep beneath the phanerozoic domains implying that the average thermal gradient is higher in the phanerozoic lithosphere than in the precambrian part

thermal hydraulic measurements and modelling of the brine circuit in a geothermal well wellhead temperature and pressure are critical parameters of a geothermal well their prediction requires knowledge of the geofluid properties and detailed thermal modelling of the well and formation high salinity and gas content complicate the task this article presents a comprehensive thermal hydraulic wellbore model which is parameterized and validated with data from the gross schoenebeck site and used for a long term prognosis geofluid properties are calculated based on the specific gas and salt contents by determining the vapour liquid equilibrium

the deep thermal field of the upper rhine graben abstract the upper rhine graben has a significant socioeconomic relevance as it provides a great potential for geothermal energy production the key for the utilisation of this energy resource is to understand the controlling factors of the thermal field in this area we have therefore built a data based lithospheric scale 3d structural model of the upper rhine graben and its adjacent areas in addition 3d gravity modelling was performed to constrain the internal structure of the crystalline crust consistent with seismic information based on this lithosphere scale 3d structural model the present day conductive thermal field was calculated and compared to measured temperatures our results show that the regional thermal field is mainly controlled by the configuration of the upper crust which has different thermal properties characteristic for the variscan and alpine domains temperature maxima are predicted for the upper rhine graben where thick insulating cenozoic sediments cause a thermal blanketing effect and where the underlying crustal units are characterised by high radiogenic heat production the comparison of calculated and measured temperatures overall shows a reasonable fit while locally occuring model deviations indicate where a larger influence of groundwater flow may be expected

integrated geothermal modeling on different scales in the northeast german basin geothermal modeling is an important part of large scale basin studies based on a new 3d structural model of the northeast german basin the present day regional geothermal field is modeled range and regional trend of the modeled temperature values are in agreement with the published data due to the high spatial resolution the calculated temperature distribution provides additional information with respect to areas where no measured data is available the results are used as input and boundary parameters for small scale models of geothermal energy production in general in many regions not enough data is available to define all necessary physical or chemical parameters for modeling in this context data obtained from the large scale model help to constrain unknown parameters subsequently the small scale model is used to simulate various production schemes focusing on enhanced predictions with respect to the possible lifetime of such installations the simulation results also show the need for elaborated models if reliable predictions of the temperature evolution are required

deep 3d thermal modelling for the city of berlin germany this study predicts the subsurface temperature distribution of germany s capital berlin for this purpose a data based lithosphere scale 3d structural model is developed incorporating 21 individual geological units this model shows a horizontal grid resolution of 500 500 m and provides the geometric base for two different approaches of 3d thermal simulations 1 calculations of the steady state purely conductive thermal field and 2 simulations of coupled fluid flow and heat transport the results point out fundamentally different structural and thermal configurations for potential geothermal target units the top of the triassic middle buntsandstein strongly varies in depth 159 2 470 m below sea level and predicted temperatures 15 95 c mostly because of the complex geometry of the underlying permian zechstein salt the top of the sub salt sedimentary rotliegend is rather flat 2 890 3 785 m below sea level and reveals temperatures of 85 139 c the predicted 70 c isotherm is located at depths of about 1 500 2 200 m cutting the middle buntsandstein over large parts of berlin the 110 c isotherm at 2 900 3 700 m depth widely crosscuts the sedimentary rotliegend groundwater flow results in subsurface cooling the extent of which is strongly controlled by the geometry and the distribution of the tertiary rupelian clay the cooling effect is strongest where this clay rich aquitard is thinnest or missing thus facilitating deep reaching forced convective flow the differences between the purely conductive and coupled models highlight the need for investigations of the complex interrelation of flow and thermal fields to properly predict temperatures in sedimentary systems

salt as a 3d element in structural modeling example from the central european basin system abstract based on a well constrained 3d structural model of the central european basin system 3d modeling has been carried out to understand the regional scale regularities between movements of the upper permian zechstein salt and the major post permian tectonic events the 3d reconstruction of the paleo thickness of upper permian salt at the end of the permian period demonstrates that areas of thickened upper permian salt correlate with the present day distribution of the largest salt structures within the central european basin system this spatial correlation implies that the distribution of salt thickness at the end of deposition partially controlled the structural style of the basin during post permian phases of salt tectonics moreover the results of 3d salt redistribution for post permian times indicate that the initiation of salt movements took place in the triassic the triassic extensional events triggered several phases of salt movements within the coeval depocenters of the central european basin system such as the glueckstadt graben the horn graben the norwegian danish basin the fjerritslev trough and the himmerland graben and the polish basin during the late jurassic early cretaceous extensional transtensional tectonic event the strongest salt movement occurred within the central graben the lower saxony basin and the pompeckj block the intensity of the late jurassic early cretaceous phase of salt tectonics is essentially declining from the marginal areas of the central european basin system towards the horn graben the glueckstadt graben and adjacent areas the late early cretaceous early late cretaceous is characterized by tectonic quiescence without strong salt movements over the entire study area the next regional phase of salt movements was triggered by late cretaceous early cenozoic inversion involving almost the entire central european basin system in terms of renewed salt movements inversion related thick skinned salt tectonics is observed along the nw se trending elbe fault system and the teisseyre tornquist zone where strongest compressional deformations were localized on the contrary a thin skinned character of salt movements was prevailing within the largest part of the north german basin post inversion cenozoic subsidence was also accompanied by salt activity related either to diapiric rise due to regional shortening and or to local roughly e w directed extension the cenozoic phase of salt movements was especially prominent within the marginal troughs of the glueckstadt graben

evidence for a magmatic origin for carlin type gold deposits isotopic composition of sulfur in the betze post screamer deposit nevada usa we report here new sulfur isotope analyses from the betze post screamer deposit the largest carlin type gold deposit in the world carlin type deposits contain high concentrations of arsenic antimony mercury tellurium and other elements of environmental interest and are surrounded by large volumes of crust in which these elements are also enriched uncertainty about the source of sulfur and metals in and around carlin type deposits has hampered formulation of models for their origin which are needed for improved mineral exploration and environmental assessment previous studies have concluded that most carlin type deposits formed from sulfide sulfur that is largely of sedimentary origin most of these studies are based on analyses of mineral separates consisting of pre ore diagenetic pyrite with thin overgrowths of ore related arsenian pyrite rather than pure ore related pyrite our sims spot analyses of ore related pyrite overgrowths in the screamer zone of the betze post screamer deposit yield 34s values of about 1 to 4 with one value of about 7 conventional analyses of realgar and orpiment separates from throughout the deposit yield 34s values of about 5 7 with one value of 10 in the screamer zone these results along with results from an earlier sims study in the post zone of the deposit and phase equilibrium constraints indicate that early arsenian pyrite were formed from fluids of magmatic origin with variable contamination from sulfur in paleozoic sedimentary rocks later arsenic sulfides were formed from solutions to which sulfur of sedimentary origin had been added the presence of paleozoic sedimentary sulfur in carlin type deposits does not require direct involvement of hydrothermal solutions of sedimentary origin instead it could have been added by magmatic assimilation of paleozoic sedimentary rocks or by hydrothermal leaching of sulfur from wall rocks to the deposit thus the dominant process delivering sulfur arsenic gold and mineralizing fluids to carlin type systems and their surrounding country rocks was probably separation of fluids from a magmatic source

geological 3 d model of the larger altensalzwedel area germany for temperature prognosis and reservoir simulation in the framework of the german r d programme clean co2 large scale enhanced gas recovery in the altmark natural gas field the geological structure of an area encompassing the altensalzwedel sub field and its surrounding was analysed in detail a 3 d model was developed that contains the major geological formations and their general lithology including the natural gas reservoir in the permian rotliegend the immediate cap rock permian zechstein of the reservoir and its overburden based on this geological model a 3 d steady state thermal model was generated as part of a shared earth model the parameterisation of the geological model layers with thermal rock properties is based on laboratory and well log data the model shows temperature changes in dependence of geological structure and of different rock thermal conductivity the calculated surface heat flow is high 80 mw m 2 for most of the area which is in accordance to measured surface heat flow temperature on top of the rotliegend reservoir is variable ranging from 110 to 150 c the quantification of temperature changes versus depth as well as laterally in the reservoir are valuable input data for modelling the dynamic processes of co2 injection within clean

characterization of main heat transport processes in the northeast german basin constraints from 3 d numerical models to investigate and quantify main physical heat driving processes affecting the present day subsurface thermal field we study a complex geological setting the northeast german basin negb the internal geological structure of the negb is characterized by the presence of a relatively thick layer of permian zechstein salt up to 5000 m which forms many salt diapirs and pillows locally reaching nearly the surface by means of three dimensional numerical simulations we explore the role of heat conduction pressure and density driven groundwater flow as well as fluid viscosity related effects our results suggest that the regional temperature distribution within the basin results from interactions between regional pressure forces as driven by topographic gradients and thermal diffusion locally enhanced by thermal conductivity contrasts between the different sedimentary rocks with the highly conductive salt playing a prominent role in contrast buoyancy forces triggered by temperature dependent fluid density variations are demonstrated to affect only locally the internal thermal configuration locations geometry and wavelengths of convective thermal anomalies are mainly controlled by the permeability field and thickness values of the respective geological layers

salinization problems in the negb results from thermohaline simulations the occurrence of salty waters close to the surface is a well known problem in the north east german basin previous numerical simulations showed that near surface brine occurrences are due to the interaction of hydrostatic and thermally induced forces mixed convection the influence of hydraulic permeabilities and thermal conductivities on the observed patterns remained an open question based on a hydro geochemical dataset thermohaline simulations are carried out in order to quantify the impact of these physical parameters on brine migration the results indicate that the salinity and temperature profiles are strongly controlled by hydraulic permeabilities and can locally be influenced by thermal conductivities

heat flow and lithospheric thermal regime in the northeast german basin abstract new values of surface heat flow are reported for 13 deep borehole locations in the northeast german basin negb ranging from 68 to 91 mw m 2 with a mean of 77 3 mw m 2 the values are derived from continuous temperature logs measured thermal conductivity and log derived radiogenic heat production the heat flow values are supposed free of effects from surface palaeoclimatic temperature variations from regional as well as local fluid flow and from thermal refraction in the vicinity of salt structures and thus represent unperturbed crustal heat flow two d numerical lithospheric thermal models are developed for a 500 km section along the dekorp basin 9601 deep seismic line across the basin with a north eastward extension across the tornquist zone a detailed conceptual model of crustal structure and composition thermal conductivity and heat production distribution is developed different boundary conditions for the thickness of thermal lithosphere were used to fit surface heat flow the best fit is achieved with a thickness of thermal lithosphere of about 75 km beneath the negb this estimate is corroborated by seismological studies and somewhat less than typical for stabilized phanerozoic lithosphere modelled moho temperatures in the basin are about 800 c heat flow from the mantle is about 35 to 40 mw m 2 in the southernmost part of the section beneath the harz mountains higher moho temperatures up to 900 to 1000 c are shown while the relatively high level of surface heat flow in the negb obviously is of longer wave length and related to lithosphere thickness changes in crustal structure and composition are responsible for short wave length anomalies

modeling of the 3d thermal field in the northeast german basin the regional thermal field of the ne german basin is modeled by a three dimensional finite element approach and is compared to classical one dimensional extrapolations two alternative boundary conditions are assumed at the approximate depth of the moho a constant temperature distribution and a constant heat flow surprisingly both results are almost identical down to approximately 10 km depth based on the models presented the results are due to a complex interaction of different strata and the related regional variability of conductivities in addition the available temperature maps for different depths hurtig et al 1992 indicate a relative high heat flow at the basin margins especially at the southern and eastern boundary the models are able to reproduce the generalized pattern by regarding only a conductive heat flow however because both models are successful at shallow depth we conclude that the current techniques of thermal modeling require improvement even on the theoretical aspects of depth continuation and inversion

how warm are passive continental margins a 3 d lithosphere scale study from the norwegian margin we model the three dimensional 3 d conductive thermal field of the norwegian margin and evaluate its lithospheric configuration which is consistent with two independent observables temperature and gravity here we show that knowledge of the sediment and crustal configuration of the passive continental margin provides constraints for the configuration and thermal structure of the lithosphere we find that the thickness of the oceanic lithosphere adjacent to the stretched continental margin controls to a large degree the shallow conductive thermal field of the entire margin our results confirm estimates of lithospheric thickness from seismology but contradict estimates from cooling models which assume an equilibrium thickness of the oceanic lithosphere of 125 km we find that the crust is colder in the oceanic than in the continental domain whereas this trend is reversed downward we obtain lateral temperature differences of 100 c at 5 km depth across the margin that increase to 400 c at 50 km depth higher temperatures and heat flows for the oceanic lithospheric mantle compared to the continent indicate that reduced upper mantle p wave velocities and densities are thermally induced

3d gravity modelling of colorado and claromeco basins new evidences for the evolution of the southwestern margin of gondwana although cratons have long been recognized as an important part of continental tectonic processes we still have much to learn about their structural features and their relation to the genesis of basins sedimentary thickness distributions fold and thrust belts and surface processes contributing to a better knowledge of the crustal state and configuration of the southernmost part of the rio de la plata craton could shed light on the still controversial tectonic processes which were responsible for the deformation of the southwestern margin of gondwana during the late paleozoic in particular the deformation and uplift of the sierras australes which are part of the claromeco basin buenos aires argentina would be closely related to the crustal structure of the southern limit of the rio de la plata craton therefore it is of crucial importance to investigate the possible existence of crustal heterogeneities underneath the claromeco basin the sierras australes and the colorado basin which can be related to structural features and weakness zones that could have played a major role in the tectonic evolution of the study area for this purpose we developed a 3d lithospheric scale density model integrating various data such as geological information global gravity models well data thicknesses and lithologies seismic tomography data moho depth and pre existing 3d density models of the colorado basin our model includes layers of sediments crystalline crust and lithospheric mantle and therefore predicts the thickness variation of the upper and lower crust in the study area and of the main sedimentary sequences infilling the basins moreover by analysing the model results we propose a tentative location of the southern limit of the rio de la plata craton and its possible tectonic relationship with transfer zones identified in the atlantic platform southwards our results suggest that the southern boundary of the craton is located along the northernmost limit of the colorado basin which is in contrast with the boundary proposed in previous works therefore we propose that the colorado basin rifting process could have occurred along this weakness domain

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

modelling of fractured carbonate reservoirs outline of a novel technique via a case study from the molasse basin southern bavaria germany fluid flow in low permeable carbonate rocks depends on the density of fractures their interconnectivity and on the formation of fault damage zones the present day stress field influences the aperture hence the transmissivity of fractures whereas paleostress fields are responsible for the formation of faults and fractures in low permeable reservoir rocks fault zones belong to the major targets before drilling an estimate for reservoir productivity of wells drilled into the damage zone of faults is therefore required due to limitations in available data a characterization of such reservoirs usually relies on the use of numerical techniques the requirements of these mathematical models encompass a full integration of the actual fault geometry comprising the dimension of the fault damage zone and of the fault core and the individual population with properties of fault zones in the hanging and foot wall and the host rock the paper presents both the technical approach to develop such a model and the property definition of heterogeneous fault zones and host rock with respect to the current stress field the case study describes a deep geothermal reservoir in the western central molasse basin in southern bavaria germany results from numerical simulations indicate that the well productivity can be enhanced along compressional fault zones if the interconnectivity of fractures is lateral caused by crossing synthetic and antithetic fractures the model allows a deeper understanding of production tests and reservoir properties of faulted rocks

experimental studies on behavior of single pile under combined uplift and lateral loading abstract1 g model experiments were carried out in the laboratory to investigate the behavior of a single pile in sand under combined uplift and lateral load dimensions of the model pile were ascertained using physical scaling laws based on adopted material properties of model and prototype pile foundations the model pile is made up of aluminum and has outer and inner diameters of 25 4 and 19 0 mm respectively different length to diameter ratios of 18 28 and 38 are considered by varying the pile length to simulate behavior of both stiff and flexible piles the test tank dimensions were chosen such that boundary effects are minimized the size of the model steel tank is 1 0 1 0 1 2 m depth experiments were performed on single piles embedded in sandy soil under independent uplift and lateral loading and combined lateral and uplift loading results indicate that the load deflection behavior is nonlinear for independent uplift and lateral load tests as well as in the case of combined loading it i

the thermal regime of the northeastern german basin from 2 d inversion abstract the thermal regime and the distribution of heat flow at the base of sedimentary basins is fundamental to the understanding of the process of basin evolution and the associated mobilization and migration of hydrocarbon and other fluids for the northeastern german sedimentary basin available information on structure temperature and thermal properties along a seismic dekorp reflection profile allow high resolution 2 d forward and inverse simulations this approach is attractive in situations where much information is available if only with considerable uncertainty in particular this allows to introduce soft information into the analysis in our case forward simulations yield initial a priori estimates of the parameters while inversion calculations yield a posteriori estimates of the parameters and their uncertainty the a priori parameters as well as their assumed uncertainty are input for a bayesian parameter estimation scheme in respect to the northeastern german sedimentary basin the inverse analysis postulates a significant and characteristic a posteriori variation of thermal conductivity of the zechstein unit along the entire profile as well as a generally large a posteriori thermal conductivity of the pre permian basement in the northern part of the basin for inverse calculations we used two alternative scenarios one assumes the thermal conductivity of the zechstein unit to be homogeneous along the profile while the other allows a lateral variation a posteriori heat flow across the base of the model varies from 40 to 60 and 50 to 65 mw m 2 for models in which values for thermal conductivity and radiogenic heat generation rate were either based on literature values or direct measurements respectively

comparison of industrial and high resolution thermal data in a sedimentary basin temperature temperature gradient and heat flow derived from four wells in the western canada sedimentary basin have been compared with similar quantities derived from maps constructed from industrial data individual industrial temperature data may differ from the high resolution temperature log by up to 30 k but linear regression of the collected data agrees within 10 k at all points observed some evidence suggests that measured conductivities using drill cuttings are biased toward average values derived heat flows show agreement of heat flow within 10 within the mesozoic section in the paleozoic section differences are greater and more varied with insufficient data for general conclusions both styles of measurement provide opportunities for interpretation each contributing to thermal analysis of sedimentary basins

structural features of the southwest african continental margin according to results of lithosphere scale 3d gravity and thermal modelling abstract to understand the structure of the southwest african continental margin a lithosphere scale 3d structural model has been developed covering the marginal cretaceous cenozoic orange luderitz walvis and namibe basins the easternmost walvis ridge offshore onshore the model includes two late proterozoic owambo etosha and nama basins this 3d model integrates published thickness maps sediment isopach maps shallow seismic and well data as well as published deep seismic information and has been additionally constrained by 3d gravity and thermal modelling using 3d gravity modelling the first order configuration of the crystalline crust has been resolved with respect to the location of the continent ocean boundary the distribution of a high density lower crustal layer indicates a continuous body extending below the cretaceous cenozoic depocentres and aligned parallel to the coast line in addition high density zones within the continental crystalline crust had to be included in the model to fit observed and calculated gravity the obtained moho topography correlates with the major tectonic units of this continental margin the results of the 3d thermal modelling indicate that there is a clear relationship between the location of thickened sediments and areas with increased temperatures within the upper 10 km of the 3d model this indicates that the low thermal conductivity of the sediments increases heat storage within the areas covered by thick sediments within the deeper crust the main feature of the temperature distribution is the transition across the continental margin from the relatively cold oceanic part to the warm continental one this regional pattern is controlled by the thickness of the crystalline continental crust which is characterized by an increased radiogenic heat production at a depth of 80 90 km the temperature becomes higher beneath the oceanic domain than beneath the continent reflecting the configuration of the lower thermal boundary which is represented by an isothermal lithosphere asthenosphere boundary

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

dike hosted ores of the beast deposit and the importance of eocene magmatism in gold mineralization of the carlin trend nevada a reply we appreciate the comments of g d langstaff and the opportunity to elaborate on the origin of carlin type gold deposits langstaff focuses on two of the critical issues regarding these deposits their age and spatial association with igneous rocks although his comment mentions almost every known carlin type deposit our reply focuses on deposits in major districts direct dating of hydrothermal minerals and indirect dating based on crosscutting relations with pre syn or postmineral rocks in nevada have demonstrated that major deposits in all trends are eocene emsbo et al 1996 leonardson and rahn 1996 phinisey et al 1996 groff et al 1997 hall et al 1997 2000 hofstra et al 1999 hofstra and cline 2000 johnston 2000 ressel et al 2000a b tretbar et al 2000 although many carlin type deposits are not dated we emphasize that no deposit has been demonstrated to be any other age preliminary 40ar 39ar dating of white micas from mineralized eocene dikes at meikle and griffin in the carlin trend gives eocene ages ressel et al 2000b any discussion of the origin especially spatial association of carlin type deposits with igneous rocks must emphasize the northern and central carlin trend fig 1 deposits there constitute 60 percent of the total estimated contained gold in carlin type deposits of nevada and utah hofstra and cline 2000 we interpreted the 700 km2 aeromagnetic anomaly fig 1 there to reflect an underlying composite eocene intrusion emplaced between about 40

thermophysical properties of coal measure strata under high temperature thermophysical properties such as specific heat capacity thermal conductivity and thermal diffusivity of coal measure strata at a wide range of temperatures are important to coal in situ gasification with environmental treatments these thermophysical properties have been investigated for different rocks but few are available for the rocks from coal measure strata this study experimentally investigated the specific heat capacity and the thermal conductivity of six types of rock samples from coal measure strata including sandy mudstone 1 and 2 mudstone siltstone coarse sandstone and fine sandstone when the testing temperature varies from 100 to 1000 c two critical temperatures 500 c for sandy mudstone 1 and 400 c for the other five types of rock samples were observed the test results show that both the specific heat capacity and the thermal conductivity decrease with the increase of temperature when the testing temperature is below the critical temperature when the testing temperature is over the critical temperature the specific heat capacity is almost constant and the thermal conductivity still continues decreasing these test results further show that the classical physics theory can well predict the experimental data for both specific heat capacity and thermal conductivity of six rocks

investigation of a new hdr system with horizontal wells and multiple fractures using the coupled wellbore reservoir simulator tough2mp well eos3 geothermal energy is renewable sustainable and available in large amounts the hot dry rock hdr systems in particular have the largest potential for long term sustainability and therefore draw a lot of attention the combination of horizontal wells and the technology of multiple transverse fractures technology is an attractive approach of such hdrs which is called in this paper as the specific egs enhanced geothermal system the main objective of this paper is to study the heat extraction over a period of 20 years by water circulating in a deep geothermal reservoir using this specific egs the wellbore flow module t2well eco2n is implemented in the parallelized simulator tough2mp as a new code tough2mp well eos3 which enables coupled wellbore reservoir simulations using this newly developed code the sensitivity of heat extraction against various parameters of the formation and fractures is assessed the influences of the fracture geometry and the space of two neighborhood fractures on the geothermal energy performance are analyzed according to the results in this paper the injection rate the wellbore radius and the fracture permeability are three main influence factors for the distribution of total flow through individual fractures a large injection rate a small wellbore radius and a large fracture width will cause the short circuit effect which reduces the performance of this specific egs compared with the classic hdr system doublet or triplet vertical wells single fracture this specific egs has a much higher performance and a longer duration of the economic production furthermore the horizontal wells can also be drilled in both directions of the minimum horizontal stress instead of in just one direction so that the energy performance is doubled and the investment cost per kw energy production is decreased and the advantage of this specific egs is significantly enlarged

interpretation and mathematical modeling of temporal changes of temperature observed in borehole yaxcopoil 1 within the chicxulub impact structure mexico summary geothermal research of the chicxulub impact structure on the yucatan peninsula mexico included repeated temperature logs following 0 3 0 8 15 24 34 and 50 months after shut in of drilling operations at the 1 5 km deep yaxcopoil 1 borehole a gradual distortion of the linear temperature profile by a cold wave propagating downward from 145 m to 317 m was detected within the observational period of 49 months march 2002 april 2006 the amplitude of the cold wave was increasing with depth and time in the range of 0 8 1 6 c as an explanation of this unusual phenomenon the hypothesis of downward migration of a large volume of drilling mud reported lost during drilling within the overlying and cooler highly porous and permeable karstic rocks has been proposed the thermal effects of the migrating fluid have been evaluated by solving numerically the heat conduction convection equation in appropriate geothermal models the best coincidence between the observed data and the simulations was yielded by the model of the drilling mud migrating as a large body parameters of this model are constrained by the measured temperature logs relatively tightly i the vertical extent of the downward migrating fluid body is about 5 10 m possibly increasing within the observational period of 49 months by a factor of 2 ii the horizontal extent of the body must be at least 15 20 m i e by order s of magnitude larger than the diameter of the borehole iii the average speed of the migration is about 5 metres per month and iv the fluid must migrate through a highly porous rock 80 porosity or more this high porosity which is necessary for the model to fit the observed data and the observed relatively stable velocity of the migration indicate the existence of a well developed system of interconnected cavities down to more than 300 m about 150 m more than the deepest cave system known in yucatan yet

thermal simulation of subsea saline permafrost thermal analyses of the response of offshore permafrost to emergence and submergence have traditionally employed simple closed form solutions where phase change is confined to a discrete freezing temperature these have led to rather rapid rates of return to thermal equilibrium which have proved difficult to explain in the light of recent deep temperature measurements in offshore permafrost profiles this paper reviews the need for an appropriate unfrozen water content relationship for a saline frozen soil and describes some simulations of long term thermal response in offshore permafrost using the author s geothermal simulator simulations of submergence assumed an initial permafrost thickness of 600 m and a mean soil surface temperature of 9 0 c the salinity was assumed constant at 30 the initial temperature profile was linear varying between 9 0 c and a freezing point of 1 8 c at the bottom of ice bonded permafrost the temperature of the ground surface was assumed to have changed to 0 8

data for distinguishing generations of quartz and a distinct gas signature of deep high grade carlin type gold mineralization using quadrupole mass spectrometry abstract carlin type gold deposits in north central nevada occur in a region that was the locus of igneous and or hydrothermal activity over time and the overprinting of silicification associated with metamorphism base metal mineralization barren jasperoid and post ore alteration hinders exploration efforts therefore the potential to distinguish unrelated generations of quartz using the results of quadrupole mass spectrometer qms gas analyses was evaluated for the getchell trend and compared to results from the goldstrike property in the carlin trend and a carlin type gold occurrence in the huijiabao trend china the results of fluid inclusion petrography qms analyses and interpretation of gas data using n 2 ar he ternary diagrams and co 2 ch 4 vs n 2 ar plots indicate that different generations of quartz in the getchell trend were deposited by hydrothermal fluids having distinct characteristics metamorphic quartz containing one phase ch 4 and halite bearing liquid water dominant vapor poor inclusions has the highest gas content 37 6 mol and highest n 2 ar values 3250 which are suggestive of an evolved magmatic fluid pre ore and quartz base metal veins contain co 2 bearing inclusions base metal veins have n 2 ar values 675 and a positive correlation between h 2 s ar vs n 2 ar that is suggestive of a magmatic fluid carlin type quartz contains liquid dominant vapor poor inclusions and is characterized by total gas contents 10 mol and n 2 ar values 300 that are suggestive of mixed crustal meteoric magmatic fluid sources post ore quartz and barren jasperoid formed from mixtures of gas poor meteoric water and crustal fluids samples of deep high grade mineralization from the goldstrike property have total gas contents up to 10 5 mol and n 2 ar values 300 fluid sources include crustal meteoric and magmatic gas data from the goldstrike property turquoise ridge deposit and metamorphic quartz of the getchell trend plot near the n 2 apex of n 2 ar he diagrams which is indicative of a magmatic fluid end member carlin type mineralization in the huijiabao trend is unique because fluids were ch 4 rich and there is a correlation between ch 4 and hydrocarbons gas analyses commonly record 2 is the dominant gas specie together the results show that fluid inclusion gases can be used to distinguish different generations of quartz in mining districts with complex origins

analysis of temperatures in sedimentary basins the michigan basin we develop an analytical and numerical methodology for the analysis of large bottom hole temperature bht data sets from sedimentary basins and test the methodology using temperature stratigraphic and lithologic data from 411 boreholes in the michigan basin least squares estimates of temperature gradients in the formations and lithologies present are calculated as solutions to a large system of linear equations at each borehole the temperature difference between the bottom and top of the hole is represented as a sum of temperature increments through the various formations or lithologies penetrated by the borehole quadratic programming techniques enable bounds to be placed on the gradient solutions in order to suppress or exclude improbable gradient estimates numerical experiments with synthetic data reveal that the estimates of temperature gradients for a given formation or lithology are sensitive to the degree of representation of that unit well represented units have more stable gradient estima

the deep geothermal potential of the berlin area in this study we model the geothermal potential of deep geological formations located in the berlin region in germany berlin is situated in a sedimentary geological setting northeastern german basin comprising low enthalpic aquifers at horizons down to 4 5 km depth in the berlin region the temperature increases almost linearly with depth by about 30 k per kilometer thus allowing for direct heating from deep aquifer reservoirs in principle our model incorporates eight major sedimentary units jurassic keuper muschelkalk upper middle lower buntsandstein zechstein salt and sedimentary rotliegend owing to lack of available petro physical rock data for the berlin region we have evaluated literature data for the larger northeastern german basin to develop a thermodynamic field model which regards depth corrected equations of state within statistical intervals of confidence integration over the thicknesses of the respective structural units yields their heat in place energy densities associated with the pore fluid and the rock matrix under local conditions in joule per unit area at the surface the model predicts that aquifers in the middle buntsandstein and in the sedimentary rotliegend may well exhibit energy densities about 10 gj m 2 for the pore fluids and 20 gj m 2 to 40 gj m 2 for the rock matrices on average referring these figures to the city area of berlin about 892 km2 a significant hydrothermal potential results which however remained undeveloped until today for the reason of present development risks the model accounts for these risks through statistical intervals of confidence which are in the order of 60 to 80 of the trend figures to minimize these uncertainties scientific field explorations were required in order to assess the petro physical aquifer properties locally

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

the geothermal potential of the underground of the salento peninsula southern italy the low enthalpy geothermal energy systems exploit the underground as a heat reservoir by coupling it with highly efficient heat pumps in winter the energy stored in the subsoil can be transferred to the surface to heat buildings whereas in summer the surplus heat in buildings can be transferred back to the ground providing a cooling action despite the high costs for installation low enthalpy geothermal systems have high energy efficiency and therefore contribute to energy saving to the use of renewable energy sources to environmental sustainability the effects on the hydrogeological cycle are often negligible and to the reduction in fuel consumption and in gas emissions in this paper a simple methodology is proposed to assess the geothermal potential of the underground of the salento peninsula southern italy at the regional scale by calculating the equivalent thermal performance of the subsoil which expresses the thermal power that is potentially extractable and useful to heat or cool a building since the possibility of exploiting the underground as a heat reservoir depends on the physical properties and water saturation of rocks previous detailed studies on the hydrostratigraphic setup of the region are the basis for this analysis of geothermal potential the equivalent thermal performance depends on the thermal efficiencies of different lithological units whose ranges of values for heating only are provided in literature for this case study a stochastic approach has been applied several combinations of thermal efficiencies were randomly selected from the intervals of reference values for every hydrostratigraphic formation and the corresponding minimum depths below the ground surface that must be reached to get the desired equivalent thermal performance are computed the results show that the underground of the salento peninsula has great potentialities for heating of buildings except for some coastal areas because the saltwater intrusion phenomenon could cause problems for the realization of low enthalpy geothermal energy systems

sedimentary rock hosted disseminated precious metal mineralization at purisima concepcion yauricocha district central peru sedimentary rock hosted disseminated gold ores lithologically and chemically similar to those of carlin type deposits of the western united states are present in the yauricocha district central peru the purisima concepcion deposit is located in the core of a steeply plunging anticline several hundred meters beyond large pipe shaped cu zn pb ag au replacement orebodies in limestone bordering a late miocene granodiorite stock the central part of the stock is potassium silicate altered and contains high salinity fluid inclusions mineralized impure limestone is generally decalcified and silicified and appears to have been carbonaceous original laminated bedding and other sedimentary structures are locally preserved characteristic minerals include quartz rhodochrosite pyrite calcite sericite and barite pyrrhotite arsenopyrite plagionite pb 5 sb 8 s 17 and altaite pbte have been recognized locally although the chemical composition of the ores is generally similar to that of the carlin deposit rocks of purisima concepcion have higher fe mn te ag and tl and lower hg contents most of the au bearing rocks contain between 3 and 6 wt percent fe and te asymp 4 ppm and mn asymp 4 wt are about two orders of magnitude higher than at carlin these elevated elemental concentrations are all epigenetic there is no regional or local geologic or textural evidence for a syngenetic and or diagenetic origin the ag au ratio of the ores is about 2 5 gold correlates positively with ag as hg mo sb te and tl and ag strongly with mn porous leached but not silicified beds tend to carry higher gold values than silicified rocks the presence of enargite tetrahedrite and high s copper sulfide minerals in the replacement ores and of pyrophyllite diaspore alunite anhydrite and high temperature or 400 degrees c compositionally complex hypersaline fluid inclusions in altered rocks bordering enargite veins in the stock and the intense dissolution of limestone during deposition of the polymetallic ore bodies suggest that the fluids initially had low ph and high f sub o 2 and f sub s 2 values the magmatic hydrothermal system may have been similar to that of julcani and other enargite tetrahedrite districts in peru with the differences in ore types at least in part reflecting the carbonate composition of the host rock at yauricocha the elemental chemistry of the purisima concepcion ores can be qualitatively explained by a process of hydrothermal differentiation in which selective precipitation of base metal and ag sulfides and sulfosalts depleted the fluids in these components and produced a decrease in cu zn cu pb as sb base metal precious metal and ag au ratios the moderate ph and low f sub o 2 and f sub s 2 values implied by the mineral assemblage of purisima concepcion presumably reflect in part the presence of carbonaceous material similar deposits can be expected elsewhere in the western cordillera of central and northern peru where hydrothermal fluids related to neogene stocks encountered impure carbonaceous limestone beds of the pariatambo and jumasha formations and other units certain sedimentary rock hosted disseminated au ag deposits elsewhere may have a similar genetic relation to porphyry skarn and or limestone replacement systems

the deep thermal field of the glueckstadt graben with this paper we assess the present day conductive thermal field of the glueckstadt graben in nw germany that is characterized by large salt walls and diapirs structuring the graben fill we use a finite element method to calculate the 3d steady state conductive thermal field based on a lithosphere scale 3d structural model that resolves the first order structural characteristics of the graben and its underlying lithosphere model predictions are validated against measured temperatures in six deep wells our investigations show that the interaction of thickness distributions and thermal rock properties of the different geological layers is of major importance for the distribution of temperatures in the deep subsurface of the glueckstadt graben however the local temperatures may result from the superposed effects of different controlling factors especially the upper sedimentary part of the model exhibits huge lateral temperature variations which correlate spatially with the shape of the thermally highly conductive permian salt layer variations in thickness and geometry of the salt cause two major effects which provoke considerable lateral temperature variations for a given depth 1 the chimney effect causes more efficient heat transport within salt diapirs as a consequence positive thermal anomalies develop in the upper part and above salt structures where the latter are covered by much less conductive sediments in contrast negative thermal anomalies are noticeable underneath salt structures 2 the thermal blanketing effect is caused by thermally low conductive sediments that provoke the local storage of heat where these insulating sediments are present the latter effect leads to both local and regional thermal anomalies locally this translates to higher temperatures where salt margin synclines are filled with thick insulating clastic sediments for the regional anomalies the cumulative insulating effects of the entire sediment fill results in a long wavelength variation of temperatures in response to heat refraction effects caused by the contrast between insulating sediments and highly conductive crystalline crust finally the longest wavelength of temperature variations is caused by the depth position of the isothermal lithosphere asthenosphere boundary defining the regional variations of the overall geothermal gradient we find that a conductive thermal model predicts observed temperatures reasonably well for five of the six available wells whereas the steady state conductive approach appears not to be valid for the sixth well

the legacy of the ne german basin reactivation by compressional buckling in contrast to previously published models for the area the seismic reflection moho is essentially flat beneath the ne german basin along the dekorp deep seismic profile basin 96 this raises the question whether the present structure of the crust and flat moho reflect the initial formation of the basin or modification by more recent processes a 2d flexural model developed for a thin elastic plate is presented together with lithospheric strength profiles calculated along the basin 9601 reflection seismic line the analysis shows a southward decrease of lithospheric strength below the basin with a lithospheric decoupling between the crust and the mantle the modelling supports the hypothesis that the present moho topography is caused by flexural buckling which caused subsidence of the ne german basin during the upper cretaceous early cenozoic inversion event this suggests that the basin is in isostatic disequilibrium and that compressive stresses are required to keep the present basin geometry

varves and mass movement deposits record distinctly different sedimentation dynamics since the late glacial lake szurpily northeastern poland the sedimentological and geochemical characteristics of sediments from lake szurpily northeastern poland can be used as a record of mass movement and climate dynamics since the allerod late glacial sediments suggest enhanced runoff conditions in the catchment after the retreat of the scandinavian ice sheet while holocene varved sediments are interrupted by mass movement deposits mmds we identified 85 thin 1 m thick mmd type 2 consists of auto and allochthonous material and represents multistage processes including erosion and deformation of underlying varved sediments rapid deposition of clastic material and redeposition of previously eroded varved sediments seismic activity or permafrost degradation was responsible for the deposition of mmd type 2 furthermore varve thickness variability suggests gleissberg and suess solar cycles before 850 bc when human impact was limited additionally 22 and 11 yr sunspot cycles are recognized in light dark laminae thickness ratios and reflect influences of solar irradiance on lacustrine productivity

quaternary channels within the northeast german basin and their relevance on double diffusive convective transport processes constraints from 3 d thermohaline numerical simulations 1 the internal geological structure of the northeast german basin negb is affected by intense salt diapirism and by the presence of several stratified aquifer complexes of regional relevance the shallow quaternary to late tertiary freshwater aquifer is separated from the underlying mesozoic saline aquifers by an embedded tertiary clay enriched aquitard rupelian aquitard an important feature of this aquitard is that hydraulic connections between the upper and lower aquifers do exist in areas where the rupelian aquitard is missing hydrogeological windows three dimensional thermohaline numerical simulations are carried out to investigate the effects of such hydrogeological windows in the rupelian aquitard on the resulting groundwater temperature and salinity distributions numerical results suggest that hydrogeological windows act as preferential domains of hydraulic interconnectivity between the different aquifers at depth and enable vigorous heat and mass transport which causes a mixing of warm and saline groundwater with cold and less saline groundwater within both aquifers in areas where the rupelian aquitard confines the mesozoic aquifer dissolved solutes from major salt structures are transported laterally giving rise to plumes of variable salinity content ranging from few hundreds of meters to several tens of kilometers furthermore destabilizing thermal buoyancy forces may overwhelm counteracting stabilizing salinity induced forces offside of salt domes this may result in buoyant upward groundwater flow transporting heat and mass to shallower levels within the same mesozoic aquifer

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

fluid dynamics driving saline water in the north east german basin in several areas of the north german basin saline water comes close to or even reaches the surface available data from wells indicate that brine stratification is under unstable conditions in the deeper underground in order to analyse the possible transport mechanisms 3d thermohaline simulations have been carried out for two different scenarios the 3d regional model 230 330 km indicates that salty water is driven to the surface by hydrostatical forces from the surrounding highlands in addition a smaller scale model 10 10 km has been constructed with a grid resolution accounting for possible convective flow the results indicate that convective flow may play a dominant role in areas with minor topography in summary the complex pattern of near surface occurrences of saline water probably results from the interaction of hydrostatic and thermal forces

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

geology of the cove mine lander county nevada and a genetic model for the mccoy cove hydrothermal system the mccoy au ag skarn and cove au ag deposits are located in the northern fish creek mountains lander county nevada through the end of mining in 2001 large scale open pit and associated underground production at the two deposits yielded 3 3 million ounces moz of au and 108 moz of ag most production was from cove making it the fourth largest ag producer in the history of nevada cove is hosted by the middle to early late triassic augusta mountain formation which consists of limestone with lesser dolostone and clastic units ore also is present locally in eocene porphyritic granodiorite dikes and sills the deposit comprises two distinct ore types a central core of polymetallic vein type ore and an outer aureole of relatively ag rich carlin style ore polymetallic veins consist of pyrite sphalerite galena dominated au and ag bearing veins veinlets stockworks crustifications and disseminations in clastic and carbonate strata and locally in the intrusions carlin style ore comprises disseminated fe as sulfides with arsenian argentiferous and auriferous components native au electrum in silty to sandy carbonate strata polymetallic vein type ore has ag au ratios of 50 1 and carlin style ore has ag au ratios that decrease from 50 1 near the feeder faults to 1 1 in one of the more distal ore zones both types of ore are associated with decarbonatized silicified and illitized rocks new structural and age data for fresh and altered intrusive rocks indicate that mineralization at cove occurred during active extension and magmatism at 39 ma 40ar 39ar fluid inclusion and d and 18o data for polymetallic vein type ore indicate that the mineralizing fluids had temperatures of 250 to 370 c and were magmatic in origin cove is located 1 6 km northeast of mccoy where early tertiary igneous activity occurred in two pulses the first pulse consisted of relatively oxidized magnetite series magma and formed the central stock at mccoy and related dikes that extend to the cove deposit this pulse occurred at 41 5 ma and produced subeconomic skarn at mccoy the second pulse consisted of relatively reduced ilmenite series magma and produced economic skarn ore at mccoy adularia from a mineralized skarn assemblage at mccoy was dated at 39 ma k ar the age data indicate that mccoy and cove formed contemporaneously the 34s data for ore stage sulfides from skarn ore at mccoy and polymetallic vein type and carlin style ore at cove indicate a common source for s for the three types of ore this source is interpreted to have been the pulse of ilmenite series magma although the volume of the carlin style ore at cove is substantially larger than that of the polymetallic vein type ore the relatively high concentrations of base metals and clear associations with igneous activity have made cove difficult to classify the new data indicate that cove is a telescoped system consisting of polymetallic vein type and porphyry related distal disseminated ores the zonation for the mccoy cove system is nearly identical to zonations described by other workers for au enriched porphyry systems in this case the porphyry center and skarn ore at mccoy comprise the proximal component and polymetallic vein type and carlin style ores at cove are the intermediate and distal components respectively economic concentrations of au occur in all three zones which are separated from one another by subeconomic concentrations of au the carlin style orebodies at cove share several important similarities with ores in classic carlin type deposits including ore characteristics associated alteration styles and host lithologic units the late eocene age of the mccoy cove system is also a typical age for carlin type deposits in the great basin the proposed genetic model for mccoy cove may have important implications for the exploration potential of intrusion related and carlin type deposits worldwide

deep structure of the argentine margin inferred from 3d gravity and temperature modelling colorado basin abstract following previous work on the colorado basin using a 3d crustal structural model we now investigate the presence of lower crustal bodies at the base of the crust using 3d lithospheric gravity modelling and calculations of the conductive thermal field our first study highlighted two fault directions and depocentres associated with thinned crust nw se in the west and ne sw at the distal margin fault relative chronology argues for two periods of extension 1 nw se faulting and thinning in the western colorado basin and 2 ne sw faulting and thinning related to the continental breakup and formation of the ne sw striking volcanic margins of the atlantic ocean in this study the geometry of modelled high density lower crustal bodies lcbs enables the reproduction of the gravimetric field as well as of the temperature measured in wells down to 4500 m the modelled lcbs correlate with geological observations 1 nw se lcbs below the deepest depocentres in the west 2 ne sw lcbs below the distal margin faults and the seaward dipping reflectors thus the proposed poly phased evolution of the margin could as well correspond to two emplacement phases of the lcbs the calculated conductive thermal field fits the measured temperatures best if the thermal properties thermal conductivity and radiogenic heat production assigned to the lcbs correspond to either high grade metamorphic rocks or to mafic magmatic intrusions to explain the possible lithology of the lcbs we propose that the two successive phases of extension are accompanied by magma supply emplaced 1 in the thinnest crust below the older nw se depocentres then 2 along the ne sw continentward boundary of the distal margin and below the volcanic seaward dipping reflectors the south african conjugate margin records only the second ne sw event and we discuss hypotheses which could explain these differences between the conjugate margins

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

hvsr technique as tool for thermal basin characterization a field example in n e italy the euganean thermal basin located in the eastern po plain italy is one of the most important thermal districts of italy euganean berician thermal district the presence of hot water in the basin has brought about its exploitation over time the thermal area has been known since the roman empire and is still of crucial interest for the profitable use of its hydro geological resources for these reasons the water cycle of the thermal area has been thoroughly studied in particular with regard to its chemical and hydrogeological properties the effects of well pumping such as subsidence and water temperature steadiness have been monitored over time in the present work the horizontal to vertical spectral ratio hvsr single station microtremor technique was applied as a non invasive geophysical tool for the characterization of a part of the euganean berician thermal district involving the municipalities of abano and montegrotto towns this study represents the first correlation between the results from microtremor geophysical surveys and the thermal basin geological structure including remote sensing data and thermal well information more than 50 hvsr measurements from single stations were collected and analysed in close correlation with the vast amount of available borehole logs well exploitation data and sar interferometry measurements collected for the monitoring of land subsidence induced by thermal water pumping the aim of the work was to evaluate the suitability of the microtremor technique for the preliminary characterization of a thermal basin in terms of resonance properties of the alluvial deposits covering the rocky bedrock evaluated by means of hvsr methods hvsr results were interpreted in terms of regional geological setting and hydrogeological properties of the subsoil our field results confirmed the existence of significant correlations between the resonance behaviour of the basin determined by the hvsr technique and the geological structures suggesting that single station measurements are a promising tool for creating a rapid and preliminary non invasive contribution to the characterization of the geothermal basin

strain localization due to structural in homogeneities in the central european basin system the large scale crustal deformations observed in the central european basin system cebs are the result of the interplay between several controlling factors among which lateral rheological heterogeneities play a key role we present a finite element integral thin sheet model of stress and strain distribution within the cebs unlike many previous models this study is based on thermo mechanical data to quantify the impact of lateral contrasts on the tectonic deformation elasto plastic material behaviour is used for both the mantle and the crust and the effects of the sedimentary fill are also investigated the consistency of model results is ensured through comparisons with observed data the results resemble the present day dynamics and kinematics when 1 a weak granite like lower crust below the elbe fault system is modelled in contrast to a stronger lower crust in the area extending north of the elbe line throughout the baltic region and 2 a transition domain in the upper mantle is considered between the shallow mantle of the variscan domain and the deep mantle beneath the east european craton eec extending from the elbe line in the south till the tornquist zone the strain localizations observed along these structural contrasts strongly enhance the dominant role played by large structural domains in stiffening the propagation of tectonic deformation and in controlling the basin formation and the evolution in the cebs

numerical investigation of the effect of vertical load on the lateral response of piles the laboratory and field test data on the response of piles under the combined action of vertical and lateral loads is rather limited the current practice for design of piles is to consider the vertical and lateral loads independent of each other this paper presents some results from three dimensional finite element analyses that show the significant influence of vertical loads on a pile s lateral response the analyses were performed in both homogeneous clayey soils and homogeneous sandy soils the results have shown that the influence of vertical loads on the lateral response of piles is to significantly increase the capacity in sandy soils and marginally decrease the capacity in clayey soils in general it was found that the effect of vertical loads in sandy soils is significant even for long piles which are as long as 30 times the pile width while in the case of clayey soils the effect is not significant for piles beyond a length of 15 times the width of the pile the design bending moments in the laterally loaded piles were also found to be dependent on the level of vertical load on the piles