multidomain petrophysically constrained inversion and geology differentiation using guided fuzzy c means clustering abstractgeophysical inversion methods are used as part of an interpretation process that seeks to differentiate geologic units to improve the reliability of geologic differentiation based on recovered images from geophysical inversions we have developed a multidomain clustering inversion algorithm that can incorporate statistical petrophysical data into a deterministic geophysical inversion framework through the use of the fuzzy c means clustering technique petrophysical data are treated in the parameter domain in the same way that geophysical data are treated in the spatial domain and these two different types of data are simultaneously inverted in their respective domains through the minimization of a single common objective function the resulting physical property model honors the geophysical and petrophysical data and therefore can represent the earth better than geophysical inversion models that solely honor the geophysical data geophysical inversion and geology differentiation are generally tr

cooperative joint inversion of 3d seismic and magnetotelluric data with application in a mineral province abstractthe integration of different geophysical data has the potential to provide more accurate estimate of subsurface rock properties several methodologies and attempts have been developed over the years with the objective of reducing exploration risk we have developed a cooperative joint inversion approach intended to facilitate recovery of acoustic impedance ai using seismic and magnetotelluric mt data in this approach the mt data provided a pathway for iteratively building large scale low frequency information content not directly recoverable from the seismic data themselves the mt data provided complementary information to seismic especially in seismically complex terrains such as overthrust belts subbasalt and subsalt carbonate reefs or for targets below deep cover containing limestone concretionary layers or basalt on the other hand the seismic data provided structural information necessary to derive accurate resistivity models from mt inversion and small scale features during seis

cyclostratigraphic calibration of the frasnian late devonian time scale western alberta canada until now the duration of the frasnian stage has remained very poorly constrained hampering a detailed understanding of sedimentation processes and environmental and evolutionary change in this study timeseries analyses of high resolution 10 20 k y magnetic susceptibility data identify sixteen 405 k y eccentricity cycles in the magnetic susceptibility stratigraphy of the frasnian late devonian derived from carbonate platform and surrounding slope and basin deposits in western alberta canada previous studies demonstrated the generally consistent pattern of magnetic susceptibility change across the alberta basin and thus demonstrated the utility of magnetic susceptibility stratigraphy as a refi ned regional correlation tool compared to biostratigraphy in the present study we show that the magnetic susceptibility stratigraphy of the frasnian interval in western alberta has been signifi cantly infl uenced by astro nomical forcing using the sixteen 405 k y eccentricity cycles as a geochronometer we constructed a frasnian astronomical time scale this time scale indicates a duration of 6 5 0 4 m y for the frasnian calibrating this duration to the best available devonian chronology the absolute age of the givetian frasnian boundary is recalculated to 383 6 3 0 ma and the age of the frasnian famennian boundary is recalculated to 376 7 3 0 ma these new absolute ages take into account the astronomically derived duration of the frasnian but they also yield a narrowing of the error margins of the absolute ages by several hundreds of thousands of years

impact of geological complexity of the fruitland formation on combined co2 enhanced recovery sequestration at san juan basin pilot site abstract in this study we present well log and 3d seismic interpretations of a coalbed methane reservoir in the late cretaceous fruitland formation in the area surrounding the southwest regional partnership on carbon sequestration s san juan basin carbon sequestration pilot site in new mexico usa the interpretation incorporated geophysical logs from 38 wells located in a 23 km 2 area surrounding the pilot site which lies near the southern edge of the high rate fruitland coal production fairway located along the axis of the san juan basin log interpretations revealed three coal bearing zones upper middle and lower within the fruitland formation that are approximately 7 4 7 and 8 5 m 23 15 5 and 28 ft thick respectively the interpretations indicate that each of these coal zones is split by a parting into upper and lower beds making a total of six mappable coal beds in the area surrounding the co 2 injection well the combined thickness of the upper two coal beds in the upper coal zone varies between 3 5 and 4 8 m 11 5 to 15 7 ft and that of the middle beds from 2 to 4 3 m 6 6 to 14 1 ft thick the thickness of the individual coal beds in the lower coal zone varies from about 2 7 to 4 25 m 9 to 14 ft for the upper bed and from about 3 to 5 5 m 10 to 18 ft for the basal coal bed partings separating the upper and lower coal beds in each zone are on average about 2 m 7 ft in the upper and middle zones and about 1 m 3 5 ft in the lower zone seismic response of the upper middle and lower coal zones was interpreted and correlated through the 23 km 2 area the stratigraphic complexity of this coalbed methane reservoir is also accompanied by considerable structural disharmony between the three coal zones the reservoir complexity revealed in this study may account for lower than expected co 2 injectivity and preferential injection into the lower coal zone during the pilot test

depositional environments of lower pennsylvanian coal bearing siliciclastics of southeastern tennessee northwestern georgia and northeastern alabama u s a abstract in the cumberland plateaus of southeastern tennessee northwestern georgia and northeast alabama pennsylvanian strata are siliciclastics containing discontinuous coal seams above some of these coal seams the shale deposits contain fossils of marine or brackish fauna the entire sequence was deposited in an asymmetric foreland basin and is thickest in the southeast within this general trend there are locally thick deposits of lowermost pennsylvanian gizzard group sequences that mark subbasins conglomeratic sandstone members of the gizzard group are discontinuous and tend to be thicker in the subbasins in contrast conglomeratic to sandy units are more laterally continuous in the overlying crab orchard mountains group the pennsylvanian sequence overlies paleosols with subjacent freshwater neomorphosed shallow marine carbonates or siliciclastics of the uppermost mississippian pennington formation a provenance discrimination diagram indicates that pennsylvanian siliciclastics were derived from an orogenic source profile analysis of thick quartzose sandstone sequences indicates facies architectural elements and bounding surfaces characteristic of braided stream deposits a dominant southwest paleoflow direction is inferred from paleocurrent indicators in sandy braided and meandering stream deposits

controls on permo carboniferous precipitation over tropical pangaea a gcm sensitivity study abstract a series of late paleozoic climate model simulations was developed using the genesis atmospheric general circulation model to investigate the independent roles of gondwanan deglaciation atmospheric co 2 rise and regional tectonism on the long term 10 6 yr evolution of continental precipitation over tropical pangaea the model results indicate that either deglaciation or a co 2 increase from 1 to 8 present atmospheric levels could have caused substantial drying and warming at low latitudes a result that is consistent with late paleozoic proxy records yet the atmospheric processes that led to drying differ between these cases the deglaciation of gondwana reduces low latitude temperature gradients in the southern hemisphere decreasing by as much as 60 the meridional overturning in the southern hemisphere winter cell of the hadley circulation the decline in overturning reduces convective precipitation over equatorial pangaea in contrast high levels of co 2 have little effect on the large scale meridional overturning circulation but increase continental temperatures leading to high evaporation rates and reduced available soil moisture the source of convective precipitation on land in comparison to deglaciation and p co 2 regional uplift erosion of the central pangaean mountains cpms has a secondary effect on tropical precipitation in genesis and cannot explain the long term aridification and warming of western pangaea we suggest that the deglaciation of gondwana and a concomitant rise in atmospheric p co 2 could explain much of the late paleozoic climate change over low latitude pangaea

stratigraphic and biofacies patterns in the middle pennsylvanian magoffin marine unit in the appalachian basin u s a abstract the magoffin marine unit is a middle pennsylvanian age interval of marine strata that directly overlies the taylor copeland and correlative coal zones in the appalachian basin for this study the magoffin was measured described and sampled at 17 localities along a northeast to southwest transect in the center of the middle pennsylvanian outcrop belt in eastern kentucky and west virginia throughout the study area the base of the magoffin is characterized by a thin dark highly fossiliferous limestone with a brachiopod dominated fossil assemblage the limestone base is usually overlain by a fining upward sequence consisting of fossiliferous dark shales or mudstones with mollusk dominated assemblages these dark mudstones include a fissile black shale with a distinctive posidonia fauna deposited over part of the study area the lower fining sequence is overlain by a thicker coarsening sequence bearing brachiopod dominated fossil assemblages the lower beds of the magoffin particularly the basal limestone are persistent and relatively uniform throughout the study area in contrast strata in the upper part of the magoffin sequence show a high degree of geographic variability with localities in the southwestern half of the study area showing two successive thick coarsening upward sequences of strata while those to the northeast record a single thinner coarsening upward sequence the widespread uniform nature of the basal magoffin limestone appears to indicate rapid transgressive flooding of the coal swamp and associated environments accompanied by a hiatus in clastic influx into the magoffin seaway nearshore brachiopod faunas were replaced by deeper water possibly dysaerobic adapted mollusk faunas as transgression progressed culminating in the fissile black shales and monotaxic posidonia fauna deposited beneath a localized pycnocline during maximum transgression the onset of regression is indicated by the reverse of the stratigraphic sequence of faunas observed during transgression and by the return of rapid clastic influx into the basin

seismic inversion combining rock physics and multiple point geostatistics a novel inversion technique combines rock physics and multiple point geostatistics the technique is based on the formulation of the inverse problem as an inference problem and incorporates multiple point geostatistics and conditional rock physics to characterize previously known geologic information the proposed implementation combines elements of sampling from conditional probabilities and elements of optimization the technique provides multiple solutions all consistent with the expected geology well log data seismic data and the local rock physics transformations a pattern based algorithm was selected as the multiple point geostatistics component rock physics principles are incorporated at the beginning of the process defining the links between reservoir properties e g lithology saturation and physical quantities e g compressibility density making it possible to predict situations not sampled by log data results for seismic lithofacies inversion on a synthetic test and a real data application demonstrate the validity and applicability of the proposed inversion technique

climatic vs tectonic signals in a continental extensional basin teruel ne spain from stable isotope δ18o and sequence stratigraphical evolution alluvial fans and shallow carbonate lakes interfered in the teruel half graben during the late miocene pliocene tectonic influence is recorded in alluvial and lacustrine palustrine successions with long term climate changes being recorded in detail in the isotopic signatures of carbonates episodes of tectonic activity induced alluvial fan progradation and lake retraction in the whole basin three lacustrine stages have been identified which support the idea that climate also exerted an important control on sedimentation the transition between stages 1 and 2 occurred during a tectonically calm episode due to an increase in aridity in the early turolian small fans with source areas next to the lake margin prograded inducing lake shore retraction the transition from stage 2 to 3 was caused by the superimposition of increasing tectonic activity and aridity effects our study demonstrates that discrimination of allogenic factors controlling sedimentation in continental closed basins is possible using sequence stratigraphy in combination with other techniques such as geochemistry of carbonates

clastic and core lava components of a silicic lava dome the formation of a lava dome involves fractionation of the lava into core and clastic components we show that for three separate successive andesitic lava domes that grew at soufriere hills volcano montserrat between 1999 and 2007 the volumetric proportion of the lava converted to talus or pyroclastic flow deposits was 50 90 of the lava extruded currently only 8 of the total magma extruded during the 1995 2007 eruption remains as core lava the equivalent representation in the geological record will probably be even lower most of the lava extruded at the surface flowed no further than 150 300 m from the vent before disaggregation resulting in a lava core whose shape tends to a cylinder moderate to high extrusion rates at the soufriere hills domes may have contributed to the large clastic fraction observed creating talus dissipates much of the energy that would otherwise be stored in the core lava of domes the extreme hazards from large pyroclastic flows and blasts posed by wholesale collapse of a lava dome depend largely on the size of the lava core and hence on the aggregate history of the partitioning process not on the size of the dome

climatic vs tectonic controls on peat accretion in non marine setting an example from the žacleř formation yeadonian bolsovian in the intra sudetic basin czech republic abstract the acle coalfield in the western part of the intra sudetic basin is an example of coal accumulation in an alluvial valley deposited under a long term 3 m y stable tectonic regime with climatic oscillations possibly operating on several time scales the resulting sedimentary record about 600 m thick encompasses about 60 coal bearing cycles formed in a relatively small and localized part of the valley whereas elsewhere a higher clastic input and or lower rate of subsidence resulted in deposition of strata with very little coal available data suggest that tectonics produced accommodation for sediments and via changes in topography and or size of the source area affected the volume and dispersal patterns of clastic material transported to the depocentre areas with long term tectonic stability were suitable places for recognition of climatic signals in the sedimentary record modified by the intensity of local clastic input climatic fluctuations generated coal bearing cycles probably through a variable intensity of precipitation which affected the density of vegetation cover across the landscape along with evaporation and groundwater table these factors influenced the intensity of chemical weathering and hence regulated the volume and composition of clastics delivered to the depocentre this in turn resulted in alternation of short periods of bedload dominated deposition during the seasonally dry part of the cycle with periods of dominantly suspended load and organic peat deposition during the more humid everwet part of the cycle estimated duration of the basic cycles 46 k y approximates the orbitally driven axial tilt cyclicity basic cycles are arranged into two larger scale cyclic patterns lasting for 270 k y and 1 5 m y respectively which broadly correspond with the timing of glacial maxima and minima inferred from high latitude glacial deposits of gondwanan basins all the coals of the acle coalfield display similar petrographic composition dominated by collotelinite and field observations as well as detailed petrographic study show that they formed in planar rheotrophic peat swamps where long lasting peat accretion was episodically interrupted only by major floods on a century to millennial scale

walchian conifers from the mid late pennsylvanian conemaugh group in the appalachian basin stratigraphic and depositional context and paleoclimatic significance abstract walchian conifers are indicators of seasonally dry habitats of the euramerican subtropics and tropics and are of considerable value in tracking both short term and long term pennsylvanian permian paleoclimatic changes in central pangea walchian conifer macrofossils first appeared in north america during the middle pennsylvanian but are rare in central pangean coal basins until the permian an abrupt climate change occurred near the desmoinesian missourian boundary that was characterized by global warming stronger seasonality and shorter wet phases this change coincided with the regional extinction of most tree lycopsids and the appearance of widespread high chroma calcic vertisols and aridisols only four occurrences of walchia have been reported from the pennsylvanian of the appalachian basin 1 7 11 mine of eastern ohio 2 rennersville in southwest pennsylvania and 3 charleston and 4 cedar run both in southern west virginia this paper uses recently acquired outcrop data to more fully document and reevaluate the depositional and stratigraphic context of the west virginia assemblages and their paleoclimatic and paleogeographic implications the cedar run walchia assemblage occurs in olive mudshale of an abandoned fluvial channel fill 15 8 16 9 m above the base of the ames limestone indicating an early virgilian age it consists of compressions and impressions of branches and branchlets of walchia lepidophylloides cordaites and rare neuropteroid pinnules the channel fill at this location is a component of the grafton sandstone incised valley fill previously described from the study area correlation of paleosol bounded marine cored cyclothems in the study area with their nonmarine cyclothem equivalents at charleston west virginia indicates the walchia previously reported at the mahoning coal horizon occurs between the brush creek and bakerstown coals and is therefore missourian not late desmoinesian and similar to the revised age for the 7 11 mine walchia reported from eastern ohio late pennsylvanian upland or dryland conifer communities were comprised of walchia cordaites and sigillaria which produced a forest with seed ferns as an understory the cedar run assemblage was probably transported into the valley from adjacent well drained coastal plain uplands formed during valley incision and deposited within the early transgressive systems tract it is also possible that walchia expanded into the valleys when drainage became ephemeral during more arid climatic phases the revised correlations of appalachian basin walchia horizons indicate their appearance closely followed rather than predated the abrupt climate change and extinctions at the desmoinesian missourian boundary

petrophysical seismic inversion conditioned to well log data methods and application to a gas reservoir hydrocarbon reservoirs are characterized by seismic welllog and petrophysical information which is dissimilar in spatial distribution scale and relationship to reservoir properties we combine this diverse information in a unified inverse problem formulation using a multiproperty multiscale model linking properties statistically by petrophysical relationships and conditioningthemtowell logdata twoapproacheshelpus 1markov chainmontecarlosampling whichgeneratesmanyreservoir realizationsforestimatingmediumpropertiesandposteriormarginalprobabilities and2optimizationwithaleast squaresiterativetechniquetoobtainthemostprobablemodelconfiguration our petrophysical model applied to near vertical anglestacked seismicdataandwell logdatafromagasreservoir includesadeterministic component based on a combination of wyllie and wood relationships calibrated with the well log data and a random component based on the statistical characterization of the deviations of well log data from the petrophysical transform at the petrophysical level the effects of porosity and saturation on acoustic impedance are coupled conditioning the inversion to well log data helps resolve this ambiguity the combination of well logs petrophysics and seismic inversion builds on the correspondingstrengthsofeachtypeofinformation jointlyimproving 1 cross resolution of reservoir properties 2 vertical resolution of property fields 3 compliance to the smooth trend of property fields and 4 agreement with well log data at well positions

glacier fed sandstone sheets in the weller coal measures permian allan hills antarctica abstract the upper member of the weller coal measures permian at allan hills victoria land antarctica consists of repetitive coal layers separated by sheetlike bodies of predominantly sandstone and subordinate siltstone and conglomerate all of fluvial origin investigation of the lowermost inter coal sheet wc1 reveals abrupt planar basal contacts persistent upward fining and a strong westward palaeocurrent trend three lithofacies are recognized in the wc1 sheet a small scale cross bedded pebbly sandstone which occupies most of the basal portions of the sheet b large scale cross bedded medium coarse sandstone confined to a linear ne sw belt overlying or locally replacing facies a and c siltstone and rippled fine grained sandstone which drapes and overlaps facies a and b and contains glossopteris leaves and vertebraria root traces facies distribution patterns indicate the wc1 body initiated as an abrupt sheetlike incursion of coarse sediment over a low lying mire facies a followed by entrenchment and confinement of flow as the sheet extended distally facies b facies c represents low energy floodplain sedimentation co existing with and later succeeding facies b as deposition evolved toward abandonment and eventual renewal of peat deposition relatively rapid deposition of the sandstone sheet is implied by the lack of any significant hiatus markers outsized clasts up to 45 cm in diameter one observed to display prominent striations occur sporadically throughout the wc1 including within siltstone beds of facies c these are inferred to be ice rafted deposits which together with other evidence suggest meltwater influence possibly glacial on sediment transport and deposition preliminary examination of other sandstone sheets in the upper weller indicates attributes similar to the wc1 including abrupt bases upward fining character and predominantly westward palaeocurrent patterns the allan hills exposures are believed to represent a succession of low lying mire complexes interrupted by abrupt but infrequent incursions of coarse sediment possibly by extreme meltwater floods

the impact of climate change tectonism and hydrology on the formation of carboniferous tropical intermontane mires the springhill coalfield cumberland basin nova scotia abstract both climate and tectonism are influential in determining basin and mire hydrology in the rapidly subsiding intermontane basins of euramerica which formed in response to the variscan hercynian alleghenian orogeny however the record of climate change has been muted and may therefore go unrecognized the complex interplay of climate and tectonism in a tropical continental setting is recorded in the 4 km thick westphalian a b fill of the cumberland basin thick peat accumulation was favoured at the southern basin margin where rheotrophic forested mires 4 9 km wide flourished between basin axis rivers and coalesced alluvial fans derived from the cobequid highlands as a result of their geomorphic setting the thicker coals 4 3 m exhibit distinct areal zones piedmont inner mire and riverine evidence that the forest swamps were nourished both by rainfall and by groundwater discharge from alluvial fans includes the stratigraphic affinity of thick coals and basin margin conglomerates interfingering of distal fan sheetflood and mire deposits petrographic evidence of elevated ph partial gelification of tissues and predominance of the arboreous lycopsids lepidodendron and paralycopodites whereas such groundwater supply is crucial to maintenance of modern wetlands in drier periods a subhumid climate is implied coals at joggins further removed from groundwater discharge at the basin margin are less well developed a 600 m thick coal window within the fining and reddening upward basin fill sequence at springhill is inferred to represent a coincidence of optimal groundwater supply and net subsidence the ultimate decline of peat accumulation in the basin may reflect decrease in catchment area and fan size and loss of rainshadow as the cobequid massif was denuded and the basin filled the coal window ca 6 9 10 5 yr is punctuated by non marine cyclothems of coal grey sideritic mudrock and multistorey sandstone that share similar time frames with astronomic cycles of axial precession ca 1 4 10 4 yr the stress of related climate change is inferred to have caused peat accumulation to fall into disequilibrium with sediment flux and basin subsidence the late quaternary history of certain african mires illustrates the dramatic impact of climate change especially temperature and seasonality and orographic effects on tropical continental peat accumulation aspects of the groundwater recharge model may be applicable to the westphalian stephanian intermontane mires of spain and mesozoic coal basins of northern china

deposition of a saline giant in the mississippian windsor group nova scotia and the nascent late paleozoic ice age abstract saline giants are vast marine evaporite deposits that currently have no modern analogues and remain one of the most enigmatic of chemical sedimentary rocks the mississippian windsor group ca 345 ma maritimes basin atlantic canada is a saline giant that consists of two evaporite rich sedimentary sequences that are subdivided into five subzones sequence 1 is composed almost entirely of thick halite belonging to subzone a osagean sequence 2 is in unconformable contact and comprised of stacked carbonate evaporite peritidal cycles of subzones b through e meramecian subzone b the focus of research herein documents the transition from wholly evaporitic to open marine conditions and thus preserves an exceptional window into the processes forming saline giants lithofacies stacking patterns in subzone b reveal that higher order fluctuations in relative sea level produced nine stacked parasequences interpreted to reflect high frequency glacioeustatic oscillations during the onset of the late paleozoic ice age each parasequence reflects progradation of intertidal and sabkha sediments over subtidal carbonate and evaporite deposits dissimilarities in cycle composition between sub basins imply the development of contrasting brine chemistries from differing recharge rates with the open ocean what the windsor group shows is that evaporite type is ostensibly linked to the amplitude and frequency of sea level rise and fall during deposition true saline giants like the basinwide evaporites of sequence 1 apparently require low amplitude long frequency changes in sea level to promote the development of stable brine pools that are only periodically recharged with seawater by contrast the high amplitude short frequency glacioeustatic variability in sea level that controlled the accumulation of peritidal evaporites in subzone b produce smaller subeconomic deposits with more complex facies relationships

seismic impedance inversion with fuzzy clustering constraints an example from the carlin gold district nevada usa abstract the seismic reflection method provides high resolution data that are especially useful for discovering mineral deposits under deep cover a hindrance to the wider adoption of the seismic reflection method in mineral exploration is that the data are often interpreted differently and independently of other geophysical data unless common earth models are used to link the methods during geological interpretation model based inversion of post stack seismic data allows rock units with common petrophysical properties to be identified and permits increased bandwidth to enhance the spatial resolution of the acoustic impedance model however as seismic reflection data are naturally bandlimited any inversion scheme depends upon an initial model and must deal with non unique solutions for the inversion both issues can be largely overcome by using constraints and integrating prior information we exploit the abilities of fuzzy c means clustering to constrain and to include prior information in the inversion the use of a clustering constraint for petrophysical values pushes the inversion process to select models that are primarily composed of several discrete rock units and the fuzzy c means algorithm allows some properties to overlap by varying degrees imposing the fuzzy clustering techniques in the inversion process allows solutions that are similar to the natural geologic patterns that often have a few rock units represented by distinct combinations of petrophysical characteristics our tests on synthetic models with clear and distinct boundaries show that our methodology effectively recovers the true model accurate model recovery can be obtained even when the data are highly contaminated by random noise where the initial model is homogeneous or there is minimal prior petrophysical information available we demonstrate the abilities of fuzzy c means clustering to constrain and to include prior information in the acoustic impedance inversion of a challenging magnetotelluric seismic data set from the carlin gold district usa using fuzzy c means guided inversion of magnetotelluric data to create a starting model for acoustic impedance proved important in obtaining the best result our inversion results correlate with borehole data and provided a better basis for geological interpretation than the seismic reflection images alone low values of the acoustic impedance in the basement rocks were shown to be prospective by geochemical analysis of rock cores as would be predicted for later gold mineralization in weak decalcified rocks

cordaiteans in paleotropical wetlands an ecological re evaluation abstract cordaiteans in cordaite dominated permineralized peat from pennsylvanian coals in iowa have been reconstructed as mangroves using root anatomy peat taphonomy and geochemical data macrofloral palynofloral and conodont biostratigraphy indicate that these peats come from the latest atokan blackoak coal and earliest desmoinesian cliffland coal mid moscovian both in the kalo formation thus their depositional setting can be used to evaluate the mangrove hypothesis in recent mires thick mangrove peats have accumulated in tropical to subtropical carbonate systems in contrast thick tropical freshwater peats have accumulated in siliclastic systems kalo formation coals which we interpret as freshwater deposits formed in siliciclastic depositional settings similar to those of modern tropical freshwater peat and to other pennsylvanian coals in north america interpreted as freshwater deposits in the late atokan and earliest desmoinesian mid moscovian cordaiteans and tree ferns predominated in the western interior and illinois basins lycopsids and cordaiteans predominated in the appalachian and donets basins the scarcity of lycopsid only mires in north america during the late atokan earliest desmoinesian mid moscovian suggests drier climates than during the mid to late desmoinesian late moscovian rather than indicating mangrove swamps cordaite dominated peat may indicate climates with a low rain season although most plants in cordaite dominated peat probably grew in freshwater coastal mires in climate zones with seasons of low rain may harbor mangrove taxa the changuinola swamp of panama a modern peat accumulating wetland that has a low rain season is a possible analog of ancient cordaite dominated mires in changuinola most plants require freshwater however mangroves sustained by salt water influx into the swamp grow along the seaward edge and along blackwater creeks the low rain season hypothesis has implications for understanding rainfall amount and continuity during pennsylvanian cyclothem deposition the floral succession in diverse cordaite coals from cordaiteans to tree ferns to lycopsids suggests increasingly wet climate during coal accumulation the position of these coals immediately above the sequence boundary suggests humid climate during early glacial melting for these cyclothems

application of sequence and genetic stratigraphic concepts to carboniferous coal bearing strata an example from the black warrior basin usa carboniferous strata provide an excellent example on which to test the application of genetic stratigraphic and sequence stratigraphic concepts both approaches are employed in the evaluation of the coal bearing strata of the black warrior basin south eastern usa bounding hiatal surfaces have been recognized in the succession of rock that includes the mary lee coal zone within the framework of genetic stratigraphy one genetic sequence has been identified comprised of offlap progradational and aggradational facies and onlap aggradational and transgressive facies components seven parasequence sets have been delimited according to the concepts of sequence stratigraphy these have been ascribed to transgressive highstand and shelf margin systems tracts the identification of components of these contrasting frameworks provide the basis for evaluating other carboniferous strata

seismic methods in mineral exploration and mine planning a general overview of past and present case histories and a look into the future abstractdue to high metal prices and increased difficulties in finding shallower deposits the exploration for and exploitation of mineral resources is expected to move to greater depths consequently seismic methods will become a more important tool to help unravel structures hosting mineral deposits at great depth for mine planning and exploration these methods also can be used with varying degrees of success to directly target mineral deposits at depth we review important contributions that have been made in developing these techniques for the mining industry with focus on four main regions australia europe canada and south africa a wide range of case studies are covered including some that are published in the special issue accompanying this article from surface to borehole seismic methods as well as petrophysical data and seismic modeling of mineral deposits at present high resolution 2d surveys mostly are performed in mining areas but there is a general increasing trend in the use of 3

paleoclimate controls on stratigraphic repetition of chemical and siliciclastic rocks climate is a primary control on sediment flux from continental sources into sedimentary systems in warm climates siliciclastic input is greatest under highly seasonal rainfall nonseasonal conditions favor formation of end member chemical rocks perennially wet climates are conducive to coal formation whereas dry climates produce carbonates and or evaporites stratigraphic repetition of siliciclastic and chemical rocks therefore appears to be related to paleoclimate cycles as well as to transgressive regressive events and tectonics

a study of fuzzy c means coupling for joint inversion using seismic tomography and gravity data test scenarios abstractjoint inversion the inversion of multiple geophysical data sets containing complementary information about the subsurface has the potential to significantly improve inversion results by reducing the nonuniqueness of the inverse problem one of the challenges of joint inversion is deciding how to couple the multiple physical property models if a coupling approach is used that is inconsistent with the physical truth then inversion artifacts can occur and may lead to incorrect interpretations in this paper we investigated the fuzzy c means fcm clustering approach to provide a lithological coupling of the seismic velocity and density models in joint 2d inversions of first arrival traveltimes and gravity data even though this coupling approach has been used in previous works recommendations for its effective use have not yet been developed we conducted a suite of joint inversion tests on synthetic data generated from a geologically realistic model based on magmatic massive sulfide deposits

integration of diverse physical property models subsurface zonation and petrophysical parameter estimation based on fuzzy c means cluster analyses inversions of an individual geophysical data set can be highly nonunique and it is generally difficult to determine petrophysical parameters from geophysical data we show that both issues can be addressed by adopting a statistical multiparameter approach that requires the acquisition processing and separate inversion of two or more types of geophysical data to combine information contained in the physical property models that result from inverting the individual data sets and to estimate the spatial distribution of petrophysical parameters in regions where they are known at only a few locations we demonstrate the potential of the fuzzy c means fcm clustering technique after testing this new approach on synthetic data we apply it to limited crosshole georadar crosshole seismic gamma log and slug test data acquired within a shallow alluvial aquifer the derived multiparameter model effectively outlines the major sedimentary units observed in numerous boreholes and provides plausible estimates

joint inversion of seismic traveltimes and gravity data on unstructured grids with application to mineral exploration seismic methods continue to receive interest for use in mineral exploration due to the much higher resolution potential of seismic data compared to the techniques traditionally used namely gravity magnetics resistivity and electromagnetics however the complicated geology often encountered in hard rock exploration can make data processing and interpretation difficult inverting seismic data jointly with a complementary data set can help overcome these difficulties and facilitate the construction of a common earth model we considered the joint inversion of seismic first arrival traveltimes and gravity data to recover causative slowness and density distributions our joint inversion algorithm differs from previous work by 1 incorporating a large suite of measures for coupling the two physical property models 2 slowly increasing the effect of the coupling to help avoid potential convergence issues and 3 automatically adjusting two tikhonov tradeoff parameters to achieve a desired fit to both d