envisat derived elevation changes of the greenland ice sheet and a comparison with icesat results in the accumulation area abstract we show for the first time over the greenland ice sheet that an along track method for deriving rates of elevation change can successfully be applied to envisat radar altimetry data 2002 2010 the results provide improved resolution and coverage compared to previous results obtained from cross over methods also we find that temporal changes in the elevation change rate can be derived from envisat data and show clear examples of this by generating five year running means for selected areas of the greenland ice sheet for a period between 2003 and 2009 the elevation of the ice sheets was measured by both the laser altimeter on board icesat and the radar altimeter on board envisat we compare rates of elevation change derived from icesat and envisat for this time span in which both sensors were operating we focus on the area above the equilibrium line altitude in order to specifically derive information on snow parameters a comparison of the elevation changes observed by the two sensors shows a complex pattern which can be explained regionally by model output describing the changes in both firn air content and accumulation rates

25 years of elevation changes of the greenland ice sheet from ers envisat and cryosat 2 radar altimetry abstract the shape of the large ice sheets responds rapidly to climate change making the elevation changes of these ice covered regions an essential climate variable consistent long time series of these elevation changes are of great scientific value here we present a newly developed data product of 25 years of elevation changes of the greenland ice sheet derived from satellite radar altimetry the data product is made publicly available within the greenland ice sheets project as part of the esa climate change initiative programme analyzing repeated elevation measurements from radar altimetry is widely used for monitoring changes of ice covered regions the greenland ice sheet has been mapped by conventional radar altimetry since the launch of ers 1 in 1991 which was followed by ers 2 envisat and currently cryosat 2 the recently launched sentinel 3a will provide a continuation of the radar altimetry time series since 2010 cryosat 2 has for the first time measured the changes in the coastal regions of the ice sheet with radar altimetry with its novel sar interferometric sarin mode which provides improved measurement over regions with steep slopes here we apply a mission specific combination of cross over along track and plane fit elevation change algorithms to radar data from the ers 1 ers 2 envisat and cryosat 2 radar missions resulting in 25 years of nearly continuous elevation change estimates 1992 2016 of the greenland ice sheet this analysis has been made possible through the recent reprocessing in the reaper project of data from the ers 1 and ers 2 radar missions making them consistent with envisat data the 25 years of elevation changes are evaluated as 5 year running means shifted almost continuously by one year a clear acceleration in thinning is evident in the 5 year maps of elevation following 2003 while only small elevation changes observed in the maps from the 1990s

elevation change of the antarctic ice sheet 1995 2000 from ers 2 satellite radar altimetry we analyzed antarctic ice sheet elevation change dh dt from 1995 to 2000 using 123 million elevation change measurements from european remote sensing 2 ice mode satellite radar altimeter data covering an area of about 7 2 million km sup 2 almost all drainage basins in east antarctica had average dh dt values within spl plusmn 3 0 cm year whereas drainage basins in west antarctica had substantial spatial variability with average dh dt values ranging between 11 to 12 cm year the east antarctic ice sheet had a five year trend of 1 spl plusmn 0 6 cm year where 13 out of the 14 basins had either a positive trend or a trend that was not significantly different than zero the west antarctic ice sheet had a five year trend of 3 6 spl plusmn 1 0 cm year due largely to strong negative trends of around 10 cm year for basins in marie byrd land along the pacific sector of the antarctic coast the continent as a whole had a five year dh dt trend of 0 4 spl plusmn 0 4 cm year finally time series constructed for the pine island thwaites de vicq and land glaciers in west antarctic showed five year dh dt trends from 26 to 135 cm year that were significantly more negative than the average dh dt trends in their respective basins the strongly negative dh dt values for these coastal glacier outlets are consistent with recently reported results indicating increased basal melting at these glaciers grounding lines caused by ocean thermal forcing

a reconciled estimate of ice sheet mass balance we combined an ensemble of satellite altimetry interferometry and gravimetry data sets using common geographical regions time intervals and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of earth s polar ice sheets we find that there is good agreement between different satellite methods especially in greenland and west antarctica and that combining satellite data sets leads to greater certainty between 1992 and 2011 the ice sheets of greenland east antarctica west antarctica and the antarctic peninsula changed in mass by 142 49 14 43 65 26 and 20 14 gigatonnes year 1 respectively since 1992 the polar ice sheets have contributed on average 0 59 0 20 millimeter year 1 to the rate of global sea level rise

dynamic thinning of antarctic glaciers from along track repeat radar altimetry since 2002 the envisat radar altimeter has measured the elevation of the antarctic ice sheet with a repeat cycle of 35 days this long and regular time series is processed using an along track algorithm to depict in detail the spatial and temporal pattern of elevation change for the whole ice sheet we use this dataset to examine the spatial and temporal pattern of pine island glacier pig thinning and compare it to the neighbouring glaciers we also examine additional areas especially in east antarctica whose mass balance is poorly known one advantage of the finer along track spacing of measurements is that it reveals places of dynamic thinning in regions of rapid ice flow we observe the acceleration of thinning on pig over the entire basin the volume loss increased from 7 km3 a 1 during 2002 06 to 48 km3 a 1 during 2006 10 we also observe accelerated thinning on the lower tens of kilometres of thwaites glacier with a mean thinning of 0 18 m a 1 over its entire basin during our observation period we confirm the dynamic thinning of totten glacier but we do not detect significantly accelerated thinning on any glacier elsewhere than on the coast of the amundsen sea

envisat radar altimeter measurements over continental surfaces and ice caps using the ice 2 retracking algorithm abstract this study presents the first results obtained with the envisat satellite radar altimeter ra 2 over lands and ice caps as radar altimetry was firstly devoted to ocean study this paper starts with a detailed description of the radar altimetry principle over continental surfaces a general formulation of the radar altimeter echoes according to different surface types is given and the retracking procedure ice 2 specially implemented on the envisat satellite ground segment to provide output parameters over continents is clearly presented the envisat ra 2 datasets processed with the ice 2 procedure are then mapped given an overall description of the output parameters over various surfaces the behaviour of these envisat altimetric parameters are analysed and related to main land surface characteristics such as surface volume echo specularity roughness apart from few unexpected signals which will need to be further investigated the new envisat dataset confirms the potential of inland altimetry and provides a new opportunity to monitor continental surfaces the ku band measurements confirm previous results recently obtained with the altimeters on board ers or topex poseidon and offer a temporal continuity the s band altimeter measurements are in accordance with theoretical expected ones and confirm previous topex poseidon observations in c band the s band and the use of the dual frequency thus bring new capabilities for altimetric applications with important deliveries for temporal evolution survey for instance s band will be used over continents to better detect wetlands located under vegetated areas or to better quantify wave penetration in terrestrial snowpack to accurately retrieve snow depth evolution over ice sheets the dual frequency s and ku band waveforms parameters will provide a more accurate height estimation as it will be possible to quantify the error on height measurements induced by snowpack structure change over time this will then provide a more confident survey of the ice sheets surface topography evolution the combination and complementarities with the other altimetry missions such as ers topex poseidon and jason look already promising and offer a 10 year span dataset for continental altimetry applications

ice sheet elevation change in west antarctica from ka band satellite radar altimetry satellite altimetry has been used to track changes in ice sheet elevation using a series of ku band radars in orbit since the late 1970s here we produce an assessment of higher frequency ka band satellite radar altimetry for the same purpose using saral altika measurements recorded over west antarctica altika elevations are 3 8 0 5 and 2 5 0 1 m higher than those determined from airborne laser altimetry and cryosat 2 respectively likely due to the instruments coarser footprint in the sloping coastal margins however altika rates of elevation change computed between 2013 and 2019 are within 0 6 2 4 and 0 1 0 1 cm year of airborne laser and cryosat 2 respectively indicating that trends in radar penetration are negligible the fast flowing trunks of the pine island and thwaites glaciers thinned by 117 10 and 100 20 cm year respectively amounting to a 9 reduction and a 43 increase relative to the 2000s

greenland 2012 melt event effects on cryosat 2 radar altimetry cryosat 2 data are used to study elevation changes over an area in the interior part of the greenland ice sheet during the extreme melt event in july 2012 the penetration of the radar signal into dry snow depends heavily on the snow stratigraphy and the rapid formation of refrozen ice layers can bias the surface elevations obtained from radar altimetry we investigate the change in cryosat 2 waveforms and elevation estimates over the melt event and interpret the findings by comparing in situ surface and snow pit observations from the north greenland eemian ice drilling project camp the investigation shows a major transition of scattering properties around the area and an apparent elevation increase of 56 26 cm is observed in reprocessed cryosat 2 data we suggest that this jump in elevation can be explained by the formation of a refrozen melt layer that raised the reflective surface introducing a positive elevation bias

a review and comparison of fracture mineral investigations and their application to radioactive waste disposal abstract a compilation and comparison of fracture mineral studies from the canadian and fennoscandian shields and the french massif central shows many similarities indicating larger external control over fracture mineral deposition with different rock types exerting local controls the sites investigated represent a wide range of geological settings and host rock types ranging from felsic intrusive and extrusives to ultramafic intrusives and volcanics that span an age range from 2 5 to 0 36 ga typical fracture minerals found at canadian shield sites include calcite quartz chlorite and clays and these do not appear to be dependant on age erosional depth or geological environment the fennoscandian shield has a much larger variety of fracture filling minerals with epidote zeolites prehnite fluorite pyrrhotite fe oxides serpentine graphite magnesite and barite in addition to the minerals typically found at canadian shield sites the major control on fracture mineral type is most likely variations in rock type and fluid chemistry and temperature the c and o isotopic range of calcite is very similar among sites late stage hydrothermal calcite with strongly depleted 18o values is common at many sites all of the sites have calcite with 18o isotopic values in the range of 5 to 20 pdb indicative of formation from meteoric water or basinal brines that have undergone varying degrees of water rock interaction one canadian and a few swedish sites have calcite in the shallower portion of the rock that shows isotopic evidence of dissolution and re precipitation in equilibrium with the present day waters there are some striking similarities in fluid inclusion data among sites most sites have an elevated temperature 100 300 c low salinity group of fluid inclusions within the nacl h2o system and a lower temperature 50 150 c higher salinity group of fluid inclusions within the nacl cacl2 h2o system fluid inclusion density plots show some evidence of simple cooling but most sites show two or more fluids were responsible for calcite formation the origin of most of these fluids was magmatic hydrothermal or meteoric water that had undergone varying degrees of water rock interaction but basinal brines and seawater were also possible sources several techniques and methods have been used to further characterize calcites strontium isotopes and rare earth elements can be useful to recognize different families of calcite uranium th dating has found many old calcites beyond the useful range of the technique but also some relatively young calcites that may be related to interglacial periods where fluid inclusion data exists formation temperatures were not consistent with a glacial water origin crush and leach experiments with ion and gas chromatography and thermal ion mass spectrometry have characterized inclusion fluids but special care must be used to ensure only one generation is sampled at a time cathodoluminescence and scanning electron microscopy with energy dispersive spectrometry has been useful in identifying multiple fluid generations within single calcite samples laser ablation and raman spectrometry are additional techniques that are useful in determining individual fluid inclusion chemistry and isotopes

recent ice sheet growth in the interior of greenland a continuous data set of greenland ice sheet altimeter height from european remote sensing satellites ers 1 and ers 2 1992 to 2003 has been analyzed an increase of 6 4 0 2 centimeters per year cm year is found in the vast interior areas above 1500 meters in contrast to previous reports of high elevation balance below 1500 meters the elevation change rate is 2 0 0 9 cm year in qualitative agreement with reported thinning in the ice sheet margins averaged over the study area the increase is 5 4 0 2 cm year or 60 cm over 11 years or 54 cm when corrected for isostatic uplift winter elevation changes are shown to be linked to the north atlantic oscillation

merging and analysis of elevation time series over greenland ice sheet from satellite radar altimetry spatial temporal variability and changes of greenland ice sheet elevation from 1992 to 2008 are analyzed from merged ers 1 ers 2 and envisat satellite radar altimeter data a methodology for determining intersatellite biases was developed and applied in order to merge measurements from these different satellites and to create continuous and consistent time series intersatellite biases of elevation and backscatter coefficient have shown to be significantly affected by the bias between measurements in ascending and descending orbits adjustment of elevation time series for its dependence on backscatter coefficient and other waveform parameters performed in this paper substantially reduced the amplitude of elevation seasonal variations and locally corrected elevation change rate estimates by up to several centimeters per year it was found that the correction depends not only on the variations in the waveform parameters but also on the temporal variations of the correlation gradients which represent the sensitivity of the elevation change to the change in the waveform parameters an elevation change rate of 2 8 0 2 cm year from 1992 to 2008 over 76 of the greenland ice sheet area was found increases in surface elevation from 1995 observed over the high elevation regions of greenland were followed by an elevation decrease from 2006 for the whole period of 1992 2008 the elevation increase is 4 0 0 2 cm year over 87 of the area above 1500 m in contrast over 38 of the low elevation areas below 1500 m the rate of elevation change is 7 0 1 0 cm year and the surface elevation decrease that started from 2000 has continued

implications of changing scattering properties on greenland ice sheet volume change from cryosat 2 altimetry abstract long term observations of surface elevation change of the greenland ice sheet gris is of utmost importance when assessing the state of the ice sheet satellite radar altimetry offers a long time series of data over the gris starting with ers 1 in 1991 esa s cryosat 2 mission launched in 2010 provides an invaluable radar altimetry dataset for monitoring the current changes of the ice sheets due to its dense spatial and temporal coverage of these areas here we investigate the effects of including different parameters which describe the shape of the return radar waveform waveform parameters in the elevation change algorithm to correct for temporal changes in the ratio between surface and volume scatter in cryosat 2 observations we present elevation and volume changes for the greenland ice sheet in the period from 2010 until 2014 the waveform parameters considered here are the backscatter coefficient and the leading edge width which are both available in the esa cryosat 2 level 2i data product investigations into relocation of radar reflection points are also included inter comparison of the cryosat 2 derived elevation changes with those derived from operation icebridge laser data suggests waveform parameters to be applicable for correcting for changes in volume scattering the best results in the synthetic aperture radar interferometric mode area of the gris are found when applying only the backscatter correction whereas the best result in the low resolution mode area is obtained by only applying a leading edge width correction using this approach to correct for the scattering properties a volume loss of 292 38 km 3 yr 1 is found for the gris for the time span november 2010 until november 2014 the inclusion of waveform parameter corrections and improved relocation for the gris helps to reconcile the satellite derived elevation changes with those observed by operation icebridge however the bias of temporal changes in the scattering horizons of cryosat 2 is not entirely removed and suggests that future improvements could be made by including climate data and or additional waveform parameters to make additional corrections in the cryosat 2 radar altimetry

compensating changes in the penetration depth of pulse limited radar altimetry over the greenland ice sheet changes in firn properties affect the shape of pulse limited radar altimeter echoes acquired over the polar ice sheets we apply a waveform deconvolution model to cryosat 2 low resolution mode echoes to determine the depth distribution of radar backscattering across the greenland ice sheet the deconvolution allows us to calculate the relative contributions of surface and volume scattering and the effective penetration depth of the radar echoes into the snowpack the most prominent signal is associated with the extreme surface melting of summer 2012 which resulted in a shift of the dominant radar scattering horizon toward the snow surface in the accumulation zone at locations above 2000 m the average penetration depth in july 2012 prior to the melt event was 3 79 1 12 m following the melt event there was an abrupt reduction in the average penetration depth across the same region to 1 45 0 94 m the average penetration depth then gradually increased to 3 28 1 13 m by the end of 2017 as fresh snow accumulated on the ice sheet surface although the variation in penetration is evident in surface height estimates derived from the cryosat 2 echoes the magnitude of the effect is reduced by waveform retracking using airborne laser altimeter data recorded over the same time period we show that the penetration variation can be compensated effectively by incorporating the deconvolution penetration depth into the surface height retrieval

continued evolution of jakobshavn isbrae following its rapid speedup 1 several new data sets reveal that thinning and speedup of jakobshavn isbrae continue following its recent rapid increase in speed as its floating ice tongue disintegrated the present speedup rate of 5 a 1 over much of the fast moving region appears to be a diffusive response to the initial much larger speedup near the front there is strong seasonality in speed over much of the fast flowing main trunk that shows a good inverse correlation with the seasonally varying length of a short typically 6 km floating ice tongue this modulation of speed with ice front position supports the hypothesis that the major speedup was caused by loss of the larger floating ice tongue from 1998 to 2003 analysis of image time series suggests that the transient winter ice tongue is formed when sea ice bonds glacier ice in the fjord to produce a nearly rigid mass that almost entirely suppresses calving major calving only resumes in late winter when much of this ice clears from the fjord the collapse of the ice tongue in the late 1990s followed almost immediately after a sharp decline in winter sea ice concentration in disko bay this decline may have extended the length of the calving season for several consecutive years leading to the ice tongue s collapse

assessing the past thermal and chemical history of fluids in crystalline rock by combining fluid inclusion and isotopic investigations of fracture calcite abstract fluid inclusion studies combined with the isotope geochemistry of several generations of fracture calcite from the olkiluoto research site finland has been used to better understand the past thermal and fluid history in the crystalline rock environment typically fracture mineral investigations use o and c isotopes from calcite and an estimate of the isotopic composition of the water that precipitated the calcite to perform 18 o geothermometry calculations to estimate past temperature conditions by combining fluid inclusion information with calcite isotopes one can directly measure the temperature at which the calcite formed and can better determine past fluid compositions isotopic petrologic and fluid inclusion studies at the olkiluoto research site in finland were undertaken as part of an investigation within the finnish nuclear waste disposal program the study revealed that four fluids were recorded by fracture calcites from petrologic evidence the first fluid precipitated crystalline calcite at 151 225 c with a 13 c signature of 21 to 13 9 pdb and a 18 o signature of 12 3 13 0 smow these closed fracture fillings were found at depths greater than 500 m and were formed from a high temperature low salinity na cl fluid of possible meteoric water altered by exchange with wallrock or dilute basinal origin the next fluid precipitated crystalline calcite with clay at 92 210 c with a 13 c signature of 2 6 to 3 8 pdb and a 18 o signature of 19 4 20 7 smow these closed fracture fillings were found at depths less than 500 m and were formed from a moderate to high temperature low to moderate salinity na cl fluid likely of magmatic origin the last group of calcites to form record the presence of two distinct fluid types the platy a calcite formed at 95 238 c with a 13 c signature of 12 2 to 3 8 pdb and a 18 o signature of 14 9 19 6 smow from a high temperature low salinity na cl fluid of possible magmatic origin the platy b calcite formed at 67 98 c with a 13 c signature of 13 0 to 6 2 pdb and a 18 o signature of 15 1 20 1 smow from a low temperature high salinity ca na cl fluid of possible basinal brine origin the two calcites are related through a mixing between the two end members the source of the fluids for the platy grey a calcites could be the olivine diabase dykes and sills that cut through the site the source of fluids for the platy b calcites could be the jotnian arkosic sandstone formations in the northern part of the site at the olkiluoto site 18 o geothermometry does not agree with fluid inclusion data the original source of the water that forms the calcite has the largest effect on the isotopic signature of the calcites formed large isotopic shifts are seen in any water by mineral precipitation during cooling under rock water equilibrium fractionation conditions different calcite isotopic signatures are produced depending on whether cooling occurred in an open or closed system water rock interaction at varying w r ratios between a water and a host rock can explain the isotopic shifts in many of the calcites observed in some cases it is possible to shift the 18 o of the water by 11 5 smow using a realistic water rock ratio this process still does not explain some of the very positive 18 o values calculated using fluid inclusion data several other processes such as low temperature recrystallization boiling kinetic effects and dissolution of calcite from fluid inclusion walls can affect isotopic signatures to varying degrees the discrepancy between fluid inclusion data and 18 o geothermometry at the olkiluoto site was most likely due to poor constraint on the original source of the water

consequences of slow growth for 230th u dating of quaternary opals yucca mountain nv usa thermal ionization mass spectrometry and data are reported for uranium rich opals coating fractures and cavities within the silicic tuffs forming yucca mountain nv the potential site of a high level radioactive waste repository high uranium concentrations up to 207 ppm and extremely high activity ratios up to about 106 make microsamples of these opals suitable for precise dating conventional ages range from 40 to greater than 600 ka and initial activity ratios between 1 03 and 8 2 isotopic evidence indicates that the opals have not experienced uranium mobility however wide variations in apparent ages and initial ratios for separate subsamples of the same outermost mineral surfaces positive correlation between ages and sample weights and negative correlation between ages and calculated initial are inconsistent with the assumption that all minerals in a given subsample was deposited instantaneously the data are more consistent with a conceptual model of continuous deposition where secondary mineral growth has occurred at a constant slow rate up to the present this model assumes that individual subsamples represent mixtures of older and younger material and that calculations using the resulting isotope ratios reflect an average age ages calculated using the continuous deposition model for opals imply average mineral growth rates of less than 5 mm m y the model of continuous deposition also predicts discordance between ages obtained using different radiometric methods for the same subsample differences in half lives will result in younger apparent ages for the shorter lived isotope due to the greater influence of younger materials continuously added to mineral surfaces discordant and u pb ages obtained from outermost mineral surfaces at yucca mountain support this model

fluid transfers at the basement cover interface part i subsurface recycling of trace carbonate from granitoid basement rocks france basement rocks usually contain trace amounts of disseminated carbonate minerals and sometimes also fractures veins filled with carbonates which may have a variety of origins extensive drilling has been performed of a granitoid body vienne western part of the french massif central overlain by a carbonate sedimentary sequence a situation which is representative of most of the variscan basement in western europe these unique samples provide the opportunity to investigate the behaviour of basement trace carbonate across the basin basement interface and the mass transfers throughout a series of fluid migration ranging from high ca 450 c to low down to 50 c temperature conditions study of quartz and carbonate found in fracture infillings reveals three major stages of fluid circulation namely 1 high to medium temperature late hercynian fluids which circulated in fractures developed during basement uplift 2 medium temperature mesozoic basinal brines migration laterally along the basement cover contact 3 late infiltration of diagenetic marine waters in the upper part of the granitoid body a majority of analyzed vein carbonates from the three stages displayed a rather restricted range of c isotopic compositions 13c between 14 and 9 pdb whatever the stage in which they were deposited and despite large variations of o isotopic ratios 18o in the range 3 to 30 smow carbon in pervasively altered rocks displays the same features and is distributed among the two broad groups defined using o isotopic ratios in veins and fluid inclusions data namely the hercynian and the mesozoic carbonates isotopic data argue that carbon was introduced as carbonates in the early stages of the retrograde hercynian metamorphism and was systematically reworked by subsequent fluids without any significant carbon introduction from external sources the only exception corresponds to the stage iii calcite veins which are located in the upper sections of the cores at depths lower than 350 m beneath the basement cover boundary and are the only witnesses of element transfer from the sediments towards the basement the present data show that trapping of carbon by ca rich plutonic rocks during their cooling history confers on these rocks an efficient self sealing capacity during later fracturing and fluid flow because carbonates possess high solubility and rapid dissolution precipitation kinetics fluid circulation occurred not only in the macroscopic system of fractures but also within some volumes of the granitic matrix in order to scavenge and redistribute the early granitic trace carbonate in the event of poly cyclic carbonate redistribution the use of carbon isotopic composition to unravel the fluid origins must be exercised with caution as early c could be easily redistributed during later fluid migration episodes

mass changes of the greenland and antarctic ice sheets and shelves and contributions to sea level rise 1992 2002 changes in ice mass are estimated from elevation changes derived from 10 5 years greenland and 9 years antarctica of satellite radar altimetry data from the european remote sensing satellites ers 1 and 2 for the first time the dh dt values are adjusted for changes in surface elevation resulting from temperature driven variations in the rate of firn compaction the greenland ice sheet is thinning at the margins 42 2g t a 1 below the equilibrium line altitude ela and growing inland 53 2g t a 1 above the ela with a small overall mass gain 11 3g t a 1 0 03 mm a 1 sle sea level equivalent the ice sheet in west antarctica wa is losing mass 47 4g t a 1 and the ice sheet in east antarctica ea shows a small mass gain 16 11 gt a 1 for a combined net change of 31 12 gt a 1 0 08 mm a 1 sle the contribution of the three ice sheets to sea level is 0 05 0 03 mm a 1 t he antarctic ice shelves show corresponding mass changes of 95 11 gt a 1 in wa and 142 10 gt a 1 in ea thinning at the margins of the greenland ice sheet and growth at higher elevations is an expected response to increasing temperatures and precipitation in a warming climate the marked thinnings in the pine island and thwaites glacier basins of wa and the totten glacier basin in ea are probably ice dynamic responses to long term climate change and perhaps past removal of their adjacent ice shelves the ice growth in the southern antarctic peninsula and parts of ea may be due to increasing precipitation during the last century

an efficient regularized inversion approach for self potential data interpretation of ore exploration using a mix of logarithmic and non logarithmic model parameters abstract a very fast and efficient approach to self potential sp data inversion for ore exploration has been developed this approach is based on tikhonov regularization and the conjugate gradient method and simultaneously inverts for the depth z electric dipole moment k and angle of polarization of a buried anomalous body from sp data measured along a profile this inversion algorithm works iteratively and solves for z and k in the logarithmic space log z and log k and solves for in the linear space non logarithmic it is found that the original inversion formulation that uses the model parameters themselves z k and is unstable and divergent it is also found that the inversion formulation that uses the logarithm of the model parameters log z log k and log is unstable and divergent rather the new inversion scheme that is based on the aforementioned mixed log linear combination of the model parameters log z log k and overcomes and eliminates the mentioned instability and divergence problems the sensitivity analysis and numerical experiments investigated have indicated that the new approach has a far better and far more optimized minimization search direction this proposed technique fits the observed data by some geometrically simple body in the restricted class of vertical cylinder horizontal cylinder and sphere models the applicability of the algorithm has been demonstrated on various reliable synthetic data sets with and without noise the algorithm has been carefully and successfully applied to six real data examples with ore bodies buried in different complex geologic settings and at various depths in the subsurface the method is shown to be highly applicable for mineral exploration and is of particular value in cases where the sp observed data is due to ore body embedded in the subsurface on average it took about 40 s of computation not cpu time on a 1 ghz pc