statistical probability distribution of snow depth at the model sub grid cell spatial scale comprehensive snow depth data collected using georadar and hand probing were used for statistical analyses of snow depths inside 1 km grid cells the sub grid cell spatial scale was 100 m statistical distribution functions were found to have varying parameters and an attempt was made to connect these statistical parameters to different terrain variables the results showed that the two parameters mean and standard deviation of snow depth were significantly related to the sub grid terrain characteristics linear regression models could explain up to 50 of the variation for both of the snowcover parameters mentioned copyright 2004 john wiley sons ltd

surface and bed topography of trapridge glacier yukon territory canada digital elevation models and derived hydraulic geometry measurements of ice thickness and surface elevation are prerequisite to many glaci ological investigations a variety of techniques has been develo ped for inter pret ation of these data including means of constructing regularly gridded digital eleva tion models dem s for use in numcrical studies here we present a simple yet stati sti cally sound method for processing ice pe netr ating radar data and descr ibe a tech nique for interpol ating these data onto a regular grid dems generatcd fort rapridge glacier yukon territory canada are used to derive geometric quantities lhal give pre liminary insights into the underlying basin scale hydrol ogical syste m this simple geo metric analysis suggests that at low water press ures a dendrilic drainage netw ork exists that evolves into a uniaxial morphology as water pressure approaches notation these pre dictions are compared to hydraulic connection probabilities based on bore hole drilling

impact of climate and humans on the range dynamics of the woolly mammoth mammuthus primigenius in europe during mis 2 the woolly mammoth mammuthus primigenius was widespread in almost all of europe during the late pleistocene however its distribution changed because of population fluctuations and range expansions and reductions during marine oxygen isotope stage 2 mis 2 these processes were highly dynamic our analyses of 318 radiocarbon dates from 162 localities obtained directly from mammoth material confirmed important changes in mammoth range between 28 6 and 14 1 ka the greenland stadial 3 interval 27 5 23 3 ka was the time of maximum expansion of the mammoth in europe during mis 2 the continuous range was soon fragmented and reduced resulting in the disappearance of mammuthus during the last glacial maximum from 21 4 to 19 2 ka in all parts of the north european plain it is not clear whether mammoths survived in the east european plain the mammoth returned to europe soon after 19 0 ka and for the next 3 4 millennia played an important role in the lifeways of epigravettian societies in eastern europe mammoths became extinct in most of europe by 14 0 ka except for core areas such as the far northeast of europe where they survived until the beginning of the holocene no significant correlation was found between the distribution of the mammoth in europe and human activity

new insights into the subglacial and periglacial hydrology of vatnajokull iceland from a distributed physical model we apply a time dependent distributed glaciohydraulic model tovatna jo kull ice cap iceland aiming to determine the large scale subglacial drainage structure theimportance of basallyderivedmeltwater theinfluence ofapermeable glacierbedand vatnajo kull s discharge contribution to major rivers in iceland the model comprisestwo coupled layersthatrepresentthesubglacialhorizonperchedona subsurfaceaquifer inthe western sector and bedrock in the eastern sector to initialize and drive the simulations we use digital elevation models of the ice surface and bed the1999 2000 measured mass balance and an estimate of subglacial geothermal heat fluxes the modelled subglacial flow field differs substantially from that derived by hydraulic potential calculations and the corresponding distribution of basal effective pressure shows a strong correlation between low effective pressure and surge prone areas in northeastern and southern sectors of vatnajo kull simulations suggest that geothermally derived basal melt may account for upto 5 of the annualglacial discharge and buried aquifers may evacuate up to 30 ofsubglacialwater time dependenttestsyieldestimatesoftheglacialdischargecomponent in various outlet rivers and suggest a possible seasonal migration of subglacial hydraulic divides this study of present dayvatnajo kull hydrology formsthe starting point for inves tigationsof its future evolution

geomorphic threshold conditions for ephemeral gully incision abstract ephemeral gully erosion in cultivated land is an important source of sediment that is frequently being overlooked and not accounted for in soil erosion studies furthermore little is known about the factors controlling ephemeral gully erosion in this paper the available information on the initiation and location of ephemeral gullies is summarised focusing on the relationship between the upslope drainage area a and the critical slope gradient s cr for ephemeral gully initiation by plotting the non linear relationship between critical slope gradient measured immediately upstream of the incision head and drainage area at the incision head for gullied sites it was possible to draw a straight line on log log paper through the lower most points for each of the available datasets representing a critical slope area relationship for incision consequently below this line no incision occurs this line or critical relation can also be written as a power function between critical slope and area although many factors vary between the different datasets the exponent of the drainage area relationship 0 4 showed very little variation the observed critical slope area relationship can be related to a simple model of channel initiation by overland flow furthermore this relationship can be used to identify potentially unstable sites where control measures should be undertaken

continuous monitoring of snowpack dynamics in alpine terrain by aboveground neutron sensing the characteristics of an aboveground cosmic ray neutron sensor crns are evaluated for monitoring a mountain snowpack in the austrian alps from march 2014 to june 2016 neutron counts were compared to continuous point scale snow depth sd and snow water equivalent swe measurements from an automatic weather station with a maximum swe of 600 mm april 2014 several spatially distributed terrestrial laser scanning tls based sd and swe maps were additionally used a strong nonlinear correlation is found for both sd and swe the representative footprint of the crns is in the range of 230 270 m in contrast to previous studies suggesting signal saturation at around 100 mm of swe no complete signal saturation was observed these results imply that crns could be transferred into an unprecedented method for continuous detection of spatially averaged sd and swe for alpine snowpacks though with sensitivity decreasing with increasing swe while initially different functions were found for accumulation and melting season conditions this could be resolved by accounting for a limited measurement depth this depth limit is in the range of 200 mm of swe for dense snowpacks with high liquid water contents and associated snow density values around 450 kg m 3 and above in contrast to prior studies with shallow snowpacks interannual transferability of the results is very high regardless of presnowfall soil moisture conditions this underlines the unexpectedly high potential of crns to close the gap between point scale measurements hydrological models and remote sensing of the cryosphere in alpine terrain

relief and palaeorelief analyses of the krakow spadzista palaeolithic site as the tools used for explanation of the site location abstract the main research task was to explain the location of the krakow spadzista gravettian site based on the analyses of land relief and deposit lithology in the surroundings field geological drilling and pit investigations geoelectric recognition tachimetric geomorphological measurements and geospatial analysis gis were carried out in the site and its immediate vicinity these investigations were supplemented with the irsl dating of the cultural layer deposits palaeosols and loess the obtained results indicate that the site was located in a depression of the karstified substratum jurassic limestones filled with clay miocene and loess pleistocene based on the results of geological and geophysical investigations we reconstructed the palaeoform parameters characterized its infilling and documented spatial lithological variability of the deposits and the cultural layer gravettian material was discovered in two partially destroyed palaeosols the lower one is a denuded initial interstadial soil and the upper one is a complex solifluction cover composed of redeposited material probably from a younger interstadial soil both units represent the younger part of the interpleniglacial the upper soil is buried by the continuous youngest loess layer which covers the area of the archaeological site completely covering the older relief the eastern part of the sowiniec horst where the site s complex is situated had a number of features useful for palaeolithic settlement it is a clearly distinguishable promontory difficult to access almost from all sides at the same time it provided a good view for hunters especially towards the rudawa river valley features of mesoclimate conditioned by relief favoured the settlement

influence of the drainage network identification method on geomorphological properties and hydrological response the influence of the method of identification of the drainage network on its geomorphological characteristics and on its hydrological response is analysed blue lines photo interpreted networks and networks generated from digital elevation models dems by an automatic algorithm are compared with field observations for two small alpine catchments the comparisons are carried out in quantitative terms by using several geomorphological indices and functions and by calculating the hydrological response of the networks as represented by their geomorphologic instantaneous unit hydrograph giuh the results show that the effect of the identification method on the geomorphological indices and on the hydrological response is significant and that the threshold area for channel initiation is not constant moreover the available data show a poor correlation between local slope and threshold area finally the influence of the threshold area on the shape of the giuh is larger when the residence time on the hillslopes is of the same order as the residence time in the network in the opposite case the variability of the flow velocity along the network seems to play an important role 1997 john wiley sons ltd

a thinned lithospheric image of the tanlu fault zone eastern china constructed from wave equation based receiver function migration 1 we apply the newly proposed wave equation based receiver function poststack migration method to the northern china interior structure project broadband data to image the lithospheric structure of the tanlu fault zone area in eastern china our migration result reveals a 60 to 80 km thick present day lithosphere beneath the study region significantly thinned from the paleozoic lithosphere of 180 km the lithosphere asthenosphere boundary lab is coherently imaged along the 300 km east west profile displaying an arc like shape with its apex roughly coincident with the transverse location of the tanlu fault zone on the surface an obvious uplift from 36 km to 32 km of the moho is also clearly detected right below this fault zone the coincidence of the imaged moho uplift and the lab apex with the surface location of the tanlu fault zone provides seismological evidence for the steep geometry and deep penetration of the fault system and indicates that the tanlu fault zone might have acted as a major channel for anthenosphere upwelling during the mesozoic cenozoic continental extension and lithospheric thinning in eastern china frequency analysis and synthetic modeling suggest that both the moho and the lab are sharp and strong the latter in particular is constrained to have a 3 7 drop in s wave velocity over a depth range of 10 km or less such a rapid velocity change at the base of the lithosphere in the study region cannot be solely explained by thermal variation but likely reflects the presence of volatiles or melt in the asthenosphere or is partially attributed to the compositional contrast between the preserved depleted and dehydrated cratonic lithospheric veneer and the uplifted hydrated and fertile asthenospheric materials

multiple isotope composition s pb h o he and ar and genetic implications for gold deposits in the jiapigou gold belt northeast china the jiapigou gold belt 150 t au one of the most important gold producing districts in china is located at the northeastern margin of the north china craton it is composed of 17 gold deposits with an average grade around 10 g t au the deposits are hosted in archean gneiss and ttg rocks and are all in shear zones or fractures of varying orientations and magnitudes the 34s values of sulfide from ores are mainly between 2 7 and 10 the pb isotope characteristics of ore sulfides are different from those of the archean metamorphic rocks and mesozoic granites and dikes and indicate that they have different lead sources the sulfur and lead isotope compositions imply that the ore forming materials might originate from multiple mainly deep sources fluid inclusions in pyrite have 3he 4he ratios of 0 6 to 2 5 ra whereas their 40ar 36ar ratios range from 1 444 to 9 805 indicating a dominantly mantle fluid with a negligible crustal component 18o values calculated from hydrothermal quartz are between 0 2 and 5 9 and d values of the fluids in the fluid inclusions in quartz are from 70 to 96 these ranges suggest dominantly magmatic water with a minor meteoric component the noble gas isotopic data along with the stable isotopic data suggest that the ore forming fluids have a dominantly mantle source with minor crustal addition

synthesizing shallow seasonal snow covers a method of synthesizing a snowfield from point field measurements which is based on the fractal structure of the water equivalent is presented two steps are involved in the synthesis first the method of fractal sum of pulses is used to generate the spatial distribution of the snow water equivalent in an array second the synthetic snowfield is adjusted to take on the statistical properties of the natural snow cover the two parameter lognormal probability density function fitted to field data is used for this purpose examples of the application of the lognormal distribution for describing the water equivalent of snow covers on various landscapes encountered in a prairie environment are presented the geometrical properties fractal dimension s of snow patches that result from melting a synthetic snow cover agree closely with those of patches of an ablated natural snow cover

using hilltop curvature to derive the spatial distribution of erosion rates 1 erosion rates dictate the morphology of landscapes and therefore quantifying them is a critical part of many geomorphic studies methods to directly measure erosion rates are expensive and time consuming whereas topographic analysis facilitates prediction of erosion rates rapidly and over large spatial extents if hillslope sediment flux is nonlinearly dependent on slope then the curvature of hilltops will be linearly proportional to erosion rates in this contribution we develop new techniques to extract hilltop networks and sample their adjacent hillslopes in order to test the utility of hilltop curvature for estimating erosion rates using high resolution 1 m digital elevation data published and new cosmogenic radionuclide analyses in the feather river basin california suggest that erosion rates vary by over an order of magnitude 10 to 250 mm kyr 1 hilltop curvature increases with erosion rates allowing calibration of the hillslope sediment transport coefficient which controls the relationship between gradient and sediment flux having constraints on sediment transport efficiency allows estimation of erosion rates throughout the landscape by mapping the spatial distribution of hilltop curvature additionally we show that hilltop curvature continues to increase with rising erosion rates after gradient limited hillslopes have emerged hence hilltop curvature can potentially reflect higher erosion rates than can be predicted by hillslope gradient providing soil production on hilltops can keep pace with erosion finally hilltop curvature can be used to estimate erosion rates in landscapes undergoing a transient adjustment to changing boundary conditions if the response timescale of hillslopes is short relative to channels

hydrothermal evolution and ore precipitation of the no 2 porphyry cu au deposit in the xiongcun district tibet evidence from cathodoluminescence fluid inclusions and isotopes abstract the no 2 porphyry cu au deposit in the xiongcun district forms part of the gangdese porphyry copper belt of tibet this study clarifies the fluid evolution and ore precipitation mechanisms of the magmatic hydrothermal system that formed the deposit by combining the results of fluid inclusion petrography microthermometry scanning electron microscope cathodoluminescence imaging and stable isotope analyses of multiple quartz dominated veins four distinct sets of quartz dominated veins and eight generations of quartz q1 q8 within the veins were identified namely from early to late early barren quartz veins v1 comprised of equigranular cl bright q1 quartz quartz pyrite chalcopyrite magnetite veins v2 containing early equigranular cl bright q1 quartz and later cl gray or cl dark q2 3 q2 q3 quartz grains intergrown with cu fe sulfides quartz molybdenite pyrite chalcopyrite veins v3 comprised of quartz grains q4 q6 characterized by subhedral comb like textures with well developed oscillatory growth zoning and late quartz veins v4 containing cl gray q7 quartz with euhedral growth zones and later cl dark q8 quartz fluid inclusions in these veins can be classified into six types b40 b40h b80 b15h b15h and b15 the b40 and b40h inclusions b80 inclusions and b15 b15h and b15h inclusions contain vapor bubbles occupying 30 60 vol 70 vol and 5 25 vol respectively in addition b15h b15h and b40h inclusions contain transparent daughter minerals halite and in some cases sylvite raman spectra showed that co2 is only present in b40 and b80 inclusions in the q1 quartz in v1 and v2 veins the dominant type of inclusions is b40 which have homogenization temperatures th of 278 c 389 c peaking at 310 c 330 c and salinities of 2 0 12 8 wt nacl equiv in q2 3 quartz in v2 veins all inclusion types were observed these were trapped at temperatures of approximately 325 c 340 c and had salinities of 1 8 69 7 wt nacl equiv in v3 veins only b15h and b15 inclusions were observed which had th values of 171 c 320 c peaking at 240 c 260 c and 173 c 317 c peaking at 210 c 230 c and salinities of 28 7 33 9 wt nacl equiv and 5 6 23 1 wt nacl equiv respectively in v4 veins only b15 inclusions were observed primary b15 inclusions in v4 veins yielded th values of 166 c 229 c peaking at 170 c 200 c and salinities of 5 1 17 1 wt nacl equiv the 3he 4he and 40ar 36ar ratios of the fluid inclusions exhibited the ranges of 0 08 0 84 ra and 451 3 1567 8 respectively and the 18ofluid and dfluid values varied from 3 2 to 5 8 and 92 8 to 80 3 respectively by integrating all results from the fluid inclusion cathodoluminescence and isotopic analyses we conclude that the initial ore forming fluids of the no 2 deposit were low salinity co2 rich single phase fluids of magmatic origin subsequently fluid immiscibility developed in the initial ore forming fluids generating hypersaline liquid and low salinity vapor phases and leading to the separation of a co2 phase plus chalcopyrite precipitation from the fluids as meteoric water was injected into the hydrothermal system the ore forming fluids gradually evolved to become meteoric water dominated low temperature low salinity and co2 poor in addition fluid cooling due to the meteoric water input resulted in molybdenite precipitation

geology and he ar s pb isotope constraints on the genesis of the sidaogou gold deposit in liaodong peninsula northeastern north china craton abstract the large sidaogou gold deposit in the liaodong peninsula is a typical alteration type gold system hosted in paleoproterozoic metamorphic rocks of gaixian formation ore paragenesis indicates sidaogou mineralization occurred in four stages 1 early ore stage s1 quartz albite 2 main ore stage s2 quartz sericite pyrite gold 3 secondary ore stage s3 quartz polymetallic sulfide scheelite biotite gold and 4 late ore stage s4 calcite ankerite quartz sulfide associated hydrothermal alterations in wall rocks are dominated by albitization s1 silicification s1 to s4 sericitization s2 sulfidation s2 to s3 and carbonatization s4 with minor biotitization s3 developed locally gold mineralization was primarily occurred in s2 stage with intensive silicification sericitization and sulfidation in metamorphic wall rocks and occurred to a lesser extent in s3 stage with weak alteration possibly due to fairly weak activity and small fluxes of the ore fluids at gold precipitation stages s2 to s3 three generations of ore related pyrite py1 py2 and py3 are identified nanosims in situ s isotope analyses show that both py1 and py2 from the s2 stage have relatively broad ranges of 34s values with significant intra grain variations py1 7 7 16 5 py2 3 7 14 8 varying between those of wall rocks 11 6 20 3 and typical magmatic sources as well as the regional contemporary magmatic hydrothermal gold system cmhgs this can be interpreted by a mixed process formed by magmatic hydrothermal fluids leaching different proportion of sulfur from wall rocks during extensive fluid rock interaction py3 in the s3 stage has relatively narrow range of 34s values py3 0 6 3 7 similar to those of adjacent cmhgs indicating a magmatic origin without notable wall rock contamination due to weak fluid rock interaction the s2 stage gold bearing pyrite py1 dominated shows 206pb 204pb ratios from 17 882 to 18 938 207pb 204pb ratios from 15 592 to 15 825 and 208pb 204pb ratios from 37 811 to 39 003 which are between those of nearby early cretaceous sanguliu granitic pluton and wall rocks 206pb 204pb i 17 958 20 085 207pb 204pb i 15 664 15 976 and 208pb 204pb i 37 474 40 021 implying that the lead was originated from mixture sources ore fluids from the s2 stage pyrite py1 dominated have 3he 4he ratios range from 0 21 0 01 to 0 57 0 03 ra average 0 34 ra indicating a crustal source with minor mantle contributions moreover the 3he 4he ratios are similar to those of the adjacent cmhgs demonstrating a similar magmatic origin for the ore fluids the 40ar 36ar ratios range from 547 to 11994 indicating that the ore fluids contained 48 to 98 crust derived radiogenic 40ar which most likely inherited from wall rocks combining the geologic evidences and isotopic results we propose that the sidaogou deposit was formed by magmatic hydrothermal fluids exsolved from sanguliu pluton or its deep magma during fluid rock interaction sulfur lead and 40ar were partly scavenged from the wall rocks and then sequestered by ore related pyrite nevertheless gold was mainly of magmatic origin our study reinforces the previous conclusion that s pb isotope compositions of ore minerals could be strongly modified by wall rocks during fluid rock interaction

relationship of the presence of a non calcareous clay loam horizon to dem attributes in a gently sloping area abstract the initial objective of this study was to identify relationships between terrain attributes and soil cover over a loessic flat area covering a limestone plateau the second objective was to determine those energy factors flow path solar radiation wind intensity which could improve the understanding of morphology and soil genesis we describe 341 field observations taken over 1600 ha of an experimental area used for monitoring the water and nitrate supply in the petite beauce region 100 km to the southwest of paris for each observation several soil variables were encoded one was the presence of a non calcareous clay loam nccl horizon relief is very smooth in this region mean slope around 0 5 the main terrain attributes were derived from a digital elevation model dem at 20 20 m and assigned to the pedological observations a multiple logistic regression was used to analyse the relationship between the nccl horizon and terrain attributes special statistics were used for aspect because of the circular nature of this variable the results show a strong relationship between the presence of nccl horizon and slope gradient and slope aspect while hydrological parameters are not correlated with this horizon the mean angle of the aspect frequency of the nccl horizon was calculated and compared to the mean angles of wind direction and solar radiation balance there is a small difference between wind direction and aspect frequency of the nccl horizon this result confirms the role of wind in the spatial pattern of soils further data are required to better understand the combination of several factors role of vegetation and the age of the reshaping

geologic and topographic controls on fast flow in the laurentide and cordilleran ice sheets ice streams are fast flowing arteries which play a vital role in the dynamics and mass balance of present day ice sheets although not fully understood fast flow dynamics are intimately coupled with geologic topographic thermal and hydrologic conditions of the underlying bed these are difficult observables beneath contemporary ice sheets hindering elucidation of the processes which govern ice streaxn behavior for past ice sheets the problem is antithetic geologic evidence of former ice streams exists but spatim and temporal histories are uncertain however detailed knowledge of bed geology and topography is available in many places we take advantage of this information to compile terrain characteristics relevant to fast flow dynamics in the laurentide and cordilleran ice sheets using seed points where fast flowing wisconsinan ice has been geologically inferred discriminant analysis of a suite of north american geologic and topographic properties yields a concise measure of ice bed coupling strength our analysis suggests that the interior plains and continental shelf regions of north america have low basal coupling relative to areas of variable relief or exposed bedrock in the cordillera and on the canadian shield we conclude that the interior plains and continental shelves are both topographically and geologically predisposed to large scale basal flows i e ice streaxns or surge lobes this result holds independent of whether the mechanism of fast flow is sediment deformation or decoupled sliding over the bed

identification of peneplains by multi parameter assessment of digital elevation models the concept of peneplains has existed since the end of the nineteenth century typical peneplains are elevated geomorphological features with a low relief surface on top they may be tilted due to tectonic activity or intersected by evolving erosion until now neither a standardized definition for peneplains nor an established procedure to identify and quantify well preserved peneplains as prominent landforms existed at present the global availability of homogeneous digital elevation models dems provides an accurate characterization of the morphology of the earth surface in this study a new numerical dem based fuzzy logic approach is presented for the delineation of peneplains solely from a morphological perspective the approach is based on a morphometric analysis of the 90 arcsec shuttle radar topography mission srtm dem four critical parameters are employed which are implemented within a geographic information system gis the parameters for the correct and unambiguous description of a flat top mountain are i slope ii curvature iii terrain ruggedness index and iv relative height the approach was developed using a test area in the central tibetan plateau which is characterized by representative and well preserved peneplains and for which additional field data were collected in order to verify the method peneplains were delineated in different regions with various geological settings for which potential peneplains were already described in the literature the results from the appalachian mountains andes massif central and new zealand confirm the robustness of the proposed approach copyright 2015 john wiley sons ltd

identification of a possible engraved venus from předmosti czech republic one gravettian feminine representation e the schematic venus of predmosti e is so different from all the others that it has always been regarded as unique the engraving which was closely examined for the purpose of comparison in this study represents a woman composed of geometric shapes including a triangular head with interior lattice work concentric ellipses for the breasts belly and pelvis a double ladder for the remaining arm hatch marks and a thigh made up of parallel vertical lines this article presents the discovery and discusses the authenticity of a second feminine anthropomorph engraved on a bone shaft fragment which is labelled as coming from the same site and is highly similar to the one described at the end of the nineteenth century the modern history of preveals that the site was used as a quarry for the extraction of loess and limestone and that tons of mammoth bones were extracted to produce spodium remarkable objects that were found both during early archaeological excavations and the site s commercial exploitation went towards private collections the history of the piece under study traces it back through a succession of owners to the collection of rene de poilloue de saint perier b 1877ed 1950 and raymonde suzanne de saint perier b 1890ed 1978 the engraving is on the periosteal surface of a limb bone from a very large mammal probably a proboscidian microscopic analysis of the bone surface and engravings identify the chronology of the grooves and their relations to the stages of the bone s alteration and fracturing starting with 1 heavy weathering of the bone surface that produced longitudinal cracks which probably led to its breakage 2 engraving of the feminine representation 3 intense mechanical and chemical attacks that smoothed all of the bone s surfaces and wore down the engravings 4 covering with a consolidation agent and most recently 5 some abrasion which resulted in the creation of a few straight lines since no evidence is found to suggest that the highly worn appearance of the engravings composing the feminine representation resulted from modifications that were meant to artificially age the periosteal surface of the bone we conclude that the engraving can be plausibly attributed to the gravettian and that further analyses are warranted

fluid inclusions and hear isotopes in pyrite from the yinjiagou deposit in the southern margin of the north china craton a mantle connection for poly metallic mineralization abstract the yinjiagou poly metallic deposit is located at the southern margin of the north china craton smncc pyrite the most economically important mineral is associated with cu mo au pb zn and ag mineralization two main mineralization stages have been identified and studied a porphyry stage including the quartz molybdenite and quartz sericite pyrite qsp veins and a vein stage including the early and the late economically most important pyrite stages three types of fluid inclusions are distinguished in quartz and pyrite including liquid rich vapor rich biphase lv and halite bearing inclusions the transmitted and infrared microthermometry produced several results 1 each of the three types of fluid inclusions is trapped in the quartz of the porphyry stage with homogenization temperatures of 335 419 c and salinities of 4 7 49 6 wt nacl equiv the coexistence of halite bearing inclusions and low density vapor rich biphase lv inclusions indicates that the fluid was boiling the boiling elevated the fe and s levels in the hyper saline fluid as reflected by the development of pyrite chalcopyrite and s daughter minerals in the halite bearing inclusions 2 the fluid in the early pyrite also displays features characteristic of boiling with homogenization temperatures of 352 400 c and salinities of 3 7 42 4 wt nacl equiv whereas the late pyrite only contains liquid rich biphase lv inclusions with homogenization temperatures of 263 354 c and salinities of 6 0 21 3 wt nacl equiv the relationship between the decreasing salinity and the corresponding decreasing homogenization temperature clearly indicates extensive mixing and dilution 3 finally the infrared calibration indicates that the impact of infrared light intensity on the microthermometric results for the yinjiagou pyrite hosted fluid inclusions is limited the he ar isotopic analysis of the fluid inclusions in the pyrite indicates two different fluid sources that involve abundant mantle input the 3he 4he ratios in the porphyry stage are relatively uniform ranging from 1 39 to 1 78 ra ra 1 39 10 6 for air corresponding to 16 22 mantle 4he contribution this relatively constant range represents the actual helium isotopic composition of the fluids emanating from the cooling intrusions at depth the range of 3he 4he ratios in the vein stage is wide varying from 0 80 to 5 26 ra corresponding to 9 65 mantle 4he the significant variation in the 3he 4he ratios in the vein stage reflects mixing between two fluids these data indicate that there are two different fluid sources and separate evolutionary processes for the porphyry and vein stages and support a multi stage mineralization model the veinlet molybdenite mineralization was induced by the boiling and associated cooling of a magma sourced fluid that emanated from intrusions at depth the qsp veins are likely to be pressure release zones and late fluid flow channels the early pyrite mineralization may be attributed to the influx of a dominantly mantle derived fluid with high 3he 4he ratio 5 26 ra which is most likely related to a later more mafic magmatic event the precipitation of the most economically important pyrite resulted from the mixing and diluting of this mantle derived fluid with a surface derived fluid additionally the high 3he 4he ratios indicate a strongly extensional setting which is most likely related to the late jurassic to early cretaceous lithospheric modification and thinning of the smncc

insights into the formation of the dasuji porphyry mo deposit north china craton gained from mineral chemistry data abstract the dasuji mo deposit is located within the northern margin of the north china craton based on vein cross cutting relationships mineral assemblages and alteration characteristics the formation of the deposit can be divided into four stages stage 1 consisting of two vein types developed in deep is characterized by k feldspathization with minor molybdenum mineralization stage 2 containing four distinct vein types is the main stage of molybdenum mineralization accompanied by sericitization and silicification stage 3 is involved in lead zinc mineralization associating with carbonatization and fluorination and stage 4 is characterized by no mineralization this paper presents new mineral magnetite rutile molybdenite and pyrite chemistry data that provide new insights into the formation of this deposit the magnetites within veins in the deposit have chemical compositions that are indicative of a magmatic origin suggesting that these magnetites hosted in quartz were captured from syn mineralization granites in the area molybdenite w pb zn and cu concentrations increase with the decreasing temperature of formation suggesting the initiation of w pb zn and cu precipitation at the end of the second stage of mineralization the stage 3 pyrite within the deposit contains the highest concentrations of pb zn and cu consistent with the pb zn cu mineralization that formed during this stage the majority of the f ion deposition occurred at the end of stage 3 and the fluids associated with stage 4 were meteoric water dominated

he ar isotope geochemistry of iron and gold deposits reveals heterogeneous lithospheric destruction in the north china craton the north china craton ncc provides a classic example for extensive destruction of the cratonic lithosphere the mesozoic magmatism which contributed to the decratonization of the ncc was also accompanied by the formation of a variety of mineral deposits in order to gain further insights into the cratonic destruction process typical iron and gold deposits are investigated here helium argon isotopic data on pyrite from typical skarn iron deposits of the beiminghe and fushan in the han xing district of the central ncc and the linglong and canzhuang gold deposits in the jiaodong district in the eastern ncc are presented in this paper the 3 he 4 he 40 ar 36 ar and 40 ar 4 he ratios show generally uniform patterns within the individual deposits and reveal a complex evolutionary history of the ore forming fluids with varying degree of crust mantle interaction the ore forming fluids associated with the gold mineralization at the jiaodong mine have higher content of fluids of mantle origin with mantle helium ranging from 1 24 to 18 02 average 6 73 n 18 in contrast the ore forming fluids related to the iron ore deposits contain less mantle contribution with mantle helium ranging from 0 12 to 4 96 average 1 29 n 10 our results suggest complex and heterogeneous crust mantle processes associated with the magmatism and metallogeny where the lithosphere of the eastern ncc was subjected to more extensive thinning and destruction as compared with that in the western part consistent with the observations from geophysical studies in the region our study demonstrates that fluids associated with the mesozoic metallogenic processes in the ncc provide useful insights into the geodynamics of destruction and refertilization of the cratonic lithosphere

geology fluid inclusions and geochemistry of the zhazixi sb w deposit hunan south china abstract the zhazixi sb w deposit in the xuefeng uplift south china exhibits a unique metal association of w and sb where the w orebodies are hosted by interlayer fractures and the sb orebodies are contained within nw trending faults this study proposes that the w and sb mineralization took place in two separate periods the mineral paragenesis of the w mineralization reveals a mass of quartz scheelite and minor calcite the mineral assemblage of the sb mineralization developed after w mineralization and consists of predominantly quartz and stibnite and small amounts of native sb berthierite chalcostibnite pyrite and chalcopyrite fluid inclusions in quartz and coexisting scheelite are dominated by two phase liquid rich aqueous inclusions at room temperature microthermometric studies suggest that ore forming fluids for w mineralization are characterized by moderate temperatures 170 270 c low salinity 3 7 wt nacl equiv low density 0 75 0 95 g cm 3 and moderate to high pressure 57 2 99 7 mpa and these fluids experienced a cooling and dilution evolution during w mineralization ore forming fluids for sb mineralization are epithermal types with low temperatures 150 230 c low salinity 4 6 wt nacl equiv moderate density 0 82 0 94 g cm 3 and high pressure 42 2 122 5 mpa and these fluids display an evident decline in homogenization temperature during sb mineralization laser raman analyses of the vapor phase indicate that the ore forming fluids for both w and sb mineralization contain a small amount of co 2 the ore forming fluids for sb mineralization are identified as predominantly originating from the continental crust as suggested by the low 3 he values 0 009 10 12 cc stp g and 3 he 4 he ratios 0 002 0 056 ra as well as high 36 ar values 1 93 10 9 cc stp g and 40 ar 36 ar ratios 909 5 2279 7 the source of s is identified to be the neoproterozoic wuqiangxi formation as traced by the 34 s v cdt values of stibnite 3 1 9 4 the 208 pb 204 pb 37 643 40 222 207 pb 204 pb 15 456 15 681 and 206 pb 204 pb 17 093 20 042 ratios suggest a mixture of lower crustal and supracrustal pb sources it is thus concluded that the ore genesis of the zhazixi sb w deposit is related to the intracontinental orogeny during the early mesozoic fluid mixing is considered to be the critical mechanism involved in w mineralization whereas a fluid cooling process is responsible for sb mineralization furthermore the absence of au is attributed to the low a s content in sb mineralizing fluids

krakow spadzista trench c2 new research and interpretations of gravettian settlement abstract this article summarizes results of the 2011 12 excavations of trench c2 at the krakow spadzista street site expanding upon the published stone inventory and animal remains discovered there in 1980 the earlier excavations provided important data about the gravettian settlement of southern poland but this more recent analysis has led to revision of the earlier information based on stratigraphic and planigraphical studies the previous cultural classification of the discovered inventory has been corrected most importantly the site area is now known not to have pavlovian early gravettian and epigravettian occupations as previously thought and the gravettian inventory from layer 6 is found to be richer and more diverse with dates around 24 20 000 14c bp the once thought presence of early gravettian settlements in the western part of lesser poland is hereby refuted and a more complex interpretation of the larger krakow spadzista sites multiple loci has been synthesized

interannual persistence of the seasonal snow cover in a glacierized catchment knowledge of the spatial snow distribution and its interannual persistence is of interest for a broad spectrum of issues in cryospheric sciences in this study snow depths derived from airborne laser scanning are analyzed for interannual persistence of the seasonal snow cover in a partly glacierized mountain area 36 km2 at the end of five accumulation periods the snow covered area varied by 16 of its temporal mean mean snow depth of the total area ranged by a factor of two 1 31 2 58 m with a standard deviation of 0 42 m interannual correlation coefficients of snow depth distribution were in the range 0 68 0 84 of the investigated area 75 was found to be interannually persistent the remaining area showed variable snow cover from year to year caused by occasional avalanches and changes in surface topography as a result of glacier retreat snow cover underwent a change from a homogeneous distribution on the former glacier surface to a more heterogeneous snow cover in the recently deglaciated terrain a geostatistical analysis shows interannual persistence in scaling behavior of snow depth in ice free terrain with scale break distances at 20 m scale invariant behavior of snow depth is indicated over 100 m on smooth glacier surfaces

oxygen isotope values of precipitation and the thermal climate in europe during the middle to late weichselian ice age abstract the oxygen isotope compositions of 28 mammoth tooth enamel samples from estonia latvia lithuania poland and denmark provide new quantitative records of the middle to late weichselian climate in northern europe the new 18 o data was combined with records of oxygen isotope values from earlier investigations on european mammoth tooth enamel and palaeogroundwaters to study the spatial patterns and temporal variations in the oxygen isotope composition of precipitation and the thermal climate over much of europe the reconstructed geographical distribution of 18 o in precipitation during 52 24 ka reflects the progressive isotopic depletion of air masses moving northeast consistent with a westerly source of moisture for the entire region and a circulation pattern similar to that of the present day regional long term average 18 o w values were 0 6 4 1 lower than at present the largest changes recorded for the currently maritime influenced southern sweden and the baltic region the application of regionally varied t slopes estimated from palaeogroundwater data and modern correlations yield reasonable estimates of glacial surface temperatures in europe and imply 2 9 c lower long term mean annual surface temperatures during the glacial period

reconstructing eroded paleovolcanoes on gran canaria canary islands using advanced geomorphometry abstract original volcanic edifices of two successive stages of gran canaria are reconstructed using a geomorphometric analysis of existent or restored paleosurfaces in the reconstruction surface fitting was applied preferably to planezes i e triangular facets of original volcano flanks and quasi planar surfaces qps those occurring on planezes or scattered slightly eroded portions derived from original cone surfaces with the help of red relief image map rrim analysis out of the long lasting mid miocene to holocene subaerial evolution of the island the late miocene fataga volcano and the subsequent pliocene roque nublo volcanoes were the largest and highest the eruptive center of fataga a composite edifice 12 2 8 8 ma that may have grown up excentrically with respect to the previous tejeda caldera is well defined by both two planezes named veneguera mogan and fataga tirajana and qps remnants its calculated original volume 1000 km3 is close to the largest stratovolcanoes on earth however its 3300 m elevation obtained by exponential fit may have been significantly lower due to the complex architecture of the summit region e g a caldera responsible for ignimbrite eruptions roque nublo a 3 7 2 9 ma stratovolcanic cone which was superimposed upon the fataga rocks 3 km west of the fataga center has left no considerable paleosurfaces behind due to heavy postvolcanic erosion yet its remnant formations preserved in a radial pattern unambiguously define its center moreover surface fitting of the outcropping rocks can be corrected taking the erosion rate for the past 3 ma into account such a corrected surface fit points to a regular shaped 3000 m high cone with a 25 km radius and ca 940 km3 original volume also comparable with the dimensions of the largest terrestrial stratovolcanoes

determination of importance for comprehensive topographic factors on landslide hazard mapping using artificial neural network a landslide is one of the natural disasters that occur in malaysia in addition to the geological factor and the rain as triggering factor topographic factors such as elevation slope angle slope aspect and curvature are considered as the main causes of landslides the study in this paper was conducted in three stages the first stage involved the extraction of extra topographic factors previous landslide studies had identified only four of the topographic factors however eight new additional factors have also been identified in this study they are general curvature longitudinal curvature tangential curvature cross section curvature surface area diagonal line length surface roughness and rugosity at this stage 13 factors were extracted from the digital elevation model the second stage involved specifying the importance of each factor the multilayer perceptron network and backpropagation algorithm were used to specify the weight of each factor results were verified using the receiver operating characteristics based on the area under the curve method in the third stage the results indicated 76 07 accuracy in predicting of landslides with slope angle as the most important factor while the tangential curvature has the least importance

metacraton nature genesis and behavior article i nfo in this paper we show with examples that cratons involved in intercontinental collisions in a lower plate position are often affected by orogenic events leading to the transformation of their margins in some cases craton interiors can also be shaped by intense collisional processes leading to the generation of intra cratonic orogenic belts we propose to call these events metacratonization and the resulting lithospheric tract metacraton metacratons can appear similar to typical orogenic belts i e active margin transformed by collisional processes but are actually sharply different their main distinctive characteristics not all are present in each metacraton are 1 absence of pre collisional events 2 absence of lithospheric thickening high pressure metamorphism being generated by subduction leading to high gradient in strain and meta morphic intensity 3 preservation of allochthonous pre collisional oceanic terranes 4 abundant post collisional magmatism associated with shear zones but not with lithospheric thickening 5 presence of high temperature low pressure metamorphism associated with post collisional magmatism 6 intraconti nental orogenic belts unrelated to subduction and oceanic basin closures reactivation of the rigid but fractured metacratonic lithosphere will cause doming asthenospheric volcanism emplacement and mineral izations due to repetitive mineral enrichments this paper provides several geological cases exemplifying these different metacratonic features in scandinavia sahara central africa and elsewhere a special focus is given to the saharan metacraton because it is where the term metacraton originated and it is a vastly ex panded tract of continental crust 5 000 000 km 2

under what conditions do parallel river networks occur abstract geologists have long recognized that channel networks can deviate from a typical dendritic form when they develop under certain geologic or topographic constraints one such deviation is the parallel form which is thought to occur when networks develop on sloping surfaces the objectives of this research are to determine the specific conditions under which parallel networks occur and the nature of the transition between dendritic and parallel networks natural and simulated channel networks are considered in this study the natural networks were obtained from the digital elevation models of basins that include remnants of the preexisting topographic surface these remnants were identified as locations with small drainage areas and topographic curvatures that are close to zero for each basin the average slope of the preexisting surface was calculated and the channel network was classified using an existing method that can distinguish five network types including dendritic and parallel based on measures that are derived from scaling invariance the natural networks become consistently parallel when the average slope of the preexisting surface exceeds about 3 simulated channel networks were also generated using a detachment limited model for fluvial erosion the parameters of the model were determined to imitate the natural basins and the average slopes of the observed preexisting surfaces were used for the slopes of the initial surfaces in the simulations the model can also produce a transition between dendritic and parallel networks for an initial slope around 3 but this transition depends on the roughness of the initial surface and the boundary conditions

origin of ore forming fluids of the haigou gold deposit in the eastern central asian orogenic belt ne china constraints from h o he ar isotopes abstract the haigou lode deposit contains 40 t of gold at an average grade of 3 5 g t and is one of the largest deposits in the jiapigou gold belt located along the eastern segment of the northern margin of the north china craton the deposit comprises 15 gold bearing quartz veins hosted in a carboniferous monzonite monzogranite stock cretaceous dikes consisting of diorite diabase and granodiorite porphyries are well developed in the deposit the diorite porphyry dikes 130 4 6 3 ma occur together with gold bearing quartz veins in nne and ne striking faults gold bearing quartz veins crosscut the diorite porphyry dikes and the veins are in turn crosscut by e w striking 124 6 2 2 ma granodiorite porphyry dikes the mineralization mainly occurs as auriferous quartz veins with minor amounts of sulfide minerals including pyrite galena chalcopyrite and molybdenite gold occurs as either native gold or calaverite common gangue minerals in the deposit include quartz sericite and calcite the deposit is characterized by various types of hydrothermal alteration including silicification sericitization chloritization potassic alteration and carbonatization three stages of hydrothermal activity have been recognized in the deposit 1 a barren quartz stage 2 a polymetallic sulfide gold stage 3 a calcite stage fluid inclusions in hydrothermal pyrites have 3he 4he ratios of 0 3 to 3 3 ra and 40ar 36ar ratios of 351 to 1353 indicating mixing of fluids of mantle and crustal origin hydrothermal quartz yielded 18o values of 1 3 to 7 2 and d values of fluid inclusions in the quartz vary between 80 and 104 these stable isotope data also suggest mixing of magmatic and meteoric fluids noble gas and stable isotopic data suggest that the ore fluids have a predominant mantle source with a significant crustal component based on the spatial association of gold bearing quartz veins with early cretaceous intrusions and the h o he ar isotopic data from the deposit and intrusions we propose that gold mineralization in the haigou deposit was formed in an extensional setting and was related to the early cretaceous mantle derived intrusions

new 40ar 39ar dating results from the shanwang basin eastern china constraints on the age of the shanwang formation and associated biota abstract the fluvio lacustrine sequence of the shanwang basin eastern china preserves a rich and important terrestrial fossil fauna and flora the exceptional preservation of these fossils reveals the dynamics of ancient mammalian ecosystems and plant biology however the timing of this sedimentary sequence has been the subject of debate for decades here we contribute to this debate by presenting the detailed results of 40 ar 39 ar analysis of the basalts above below and within the shanwang formation these dates place stringent constraints on the age of shanwang formation and associated biota 40 ar 39 ar ages obtained from basalts of the niushan and yaoshan formations which underlie and overlie the shanwang formation are 21 0 2 5 ma 2 full external error and 17 3 1 5 ma 2 full external error respectively the 40 ar 39 ar age of the basalt in the shanwang formation is 17 18 ma given the age constraints of the basalts of the yaoshan and shanwang formations the age of the shanwang biota is estimated to be ca 17 ma late burdigalian of the early miocene indicating that the deposition of this fauna coincided with the onset of the mid miocene climatic optimum the results provide new age constraints on the shanwang mammal fauna and independently support interpretations that this fauna can be assigned to chronozone mn4 and correlated with middle orleanian of the european land mammal age and to late hemingfordian of the north american land mammal age biological diversity of the shanwang formation could reflect the global scale mid miocene climatic optimum

saturation regions in catchments and their relations to soil and topographic properties abstract criteria are derived for the existence of saturated areas on draining hillslopes in natural catchments these are given in terms of soil transmissivity the hillslope gradient and its wetness state characterised by the baseflow discharge from the catchment analyses are made for idealised hillslopes with uniform soils to obtain expression for the width of the saturated zone the size of saturated zones on undulating hillslopes with gradiational soils is shown to depend strongly on topographic convergence or divergence the effects of soil transmissivity hillslope geometry and drainage flux density are lumped into a dimensionless parameter whose value determines the location of seepage boundaries on slopes of specified geometry scaling relations for seepage area in catchments of different size are shown to be generally nonlinear and depend primarily on local hillslope gradients relative predictions of seepage zone size are confirmed by observed hydrographs from three catchments with different physical characteristics

influence of glacier advance on the development of the multipart riffeltal rock glacier central austrian alps the multipart riffeltal rock glacier located in a tributary valley of the kaunertal tyrol austria is investigated to enlarge the knowledge about spatial and temporal development of rock glaciers in and at the margins of pro glacial areas and to get a better understanding of glacier rock glacier interactions the subject of interest consists of a complex system of two adjacent rock glacier tongues and various superposed lobes with differing ages origin and root zones and therefore diverse development to determine the reasons for their diverging development the internal structure and permafrost occurrence on and in the surrounding area of the rock glacier were studied by application of geomorphological mapping geophysical methods and measurement of the basal temperature of the winter snow cover bts permafrost modelling was performed on the basis of bts data and land surface parameters derived from a high resolution airborne laser scanning als digital elevation model dem additionally the als data were used to measure vertical and horizontal changes of the rock glacier surface between 2006 and 2012 glacier rock glacier interactions during and since the little ice age lia are evident for the development of the studied rock glacier a geomorphic map gives important information about the connection between glacial advance or retreat and permafrost or ground ice occurrence the combination of all information helps in the analysis of diverse kinematic action of neighbouring rock glacier tongues copyright 2014 john wiley sons ltd

geochemistry and geochronology of the banxi sb deposit implications for fluid origin and the evolution of sb mineralization in central western hunan south china abstract central western hunan in south china hosts the largest antimony belt in the world with two types of sb deposits identified sb au woxi type and sb only xikuangshan type banxi is the most representative deposit in the region with vein type sb mineralization hosted in neoproterozoic clastic rocks stibnite developing in ores and arsenopyrite mainly occurring in altered country rocks trace element contents including rare earth elements ree and isotopic ratios s pb sr nd he and ar in stibnite and or arsenopyrite were analyzed to determine the timing of ore formation and to elucidate fluid origin and evolution processes most sulfides have high ree contents 45 103 ppm moderate fractionation between lree and hree lree hree 6 38 11 56 and slightly negative eu anomalies eu eu 0 53 0 72 the 34 s values are 3 88 5 81 for stibnite and 9 25 11 82 for arsenopyrite the 206 pb 204 pb 207 pb 204 pb and 208 pb 204 pb ratios range from 18 617 to 18 635 15 695 to 15 739 and 38 965 to 38 981 for stibnite and from 18 594 to 18 609 from 15 587 to 15 698 and from 38 893 to 38 926 for arsenopyrite the 87 rb 86 sr and 87 sr 86 sr ratios are 0 3016 3 538 and 0 711463 0 717591 respectively for stibnite and 0 2251 2 214 and 0 711244 0 711565 respectively for arsenopyrite the 147 sm 144 nd and 143 nd 144 nd ratios are 0 1174 0 9816 and 0 511942 0 512768 for stibnite with end t values t 130 ma ranging from 12 4 to 6 6 and two stage model ages t 2dm ranging from 1457 to 1932 ma the 40 ar 36 ar and r ra ratios where ra is the atmospheric 3 he 4 he ratio of 1 4 10 6 are 409 545 and 0 0088 0 0348 respectively for stibnite the rb sr and sm nd isotopic analyses of the sulfides yield isochron ages of 129 4 2 4 ma 2 mswd 1 3 and 130 4 1 9 ma 2 mswd 1 6 respectively the combined trace element and isotopic data set indicates that the ore forming fluids were a mixture of dominantly deep basement derived solute rich parent water and a small amount of dilute heated meteoric water the decreases in ree 34 s 206 pb 204 pb 207 pb 204 pb 208 pb 204 pb 87 rb 86 sr 87 sr 86 sr 147 sm 144 nd and 143 nd 144 nd and increases in 40 ar 36 ar and 4 he contents in the stibnite from the earlier quartz stibnite mineralization stage stage ii through to the later stibnite mineralization stage stage iii indicate that the influx of meteoric water increased during sb mineralization the deep sourced relatively high temperature rock reacted fluid mixed with increasing amounts of more oxidized low temperature meteoric fluids causing the precipitation of arsenopyrite and stibnite sequentially at the banxi deposit a two period genetic model has been proposed for the world class sb mineralization in the central western hunan region the woxi type sb au deposits were derived from orogenic fluids generated from folding and shearing during the caledonian and indosinian orogeny whereas the xikuangshan type sb deposits were formed by mixing heated basement derived hydrothermal fluid circulating during the flare up of magmatism in south china with lower temperature meteoric water

earthquake induced rockfall hazard zoning abstract a methodology for quantitative probabilistic hazard zonation for earthquake induced rockfalls is presented and demonstrated in the area of friuli eastern italian alps affected by the 1976 mw 6 5 earthquake four rockfall datasets have been prepared both from historical data analysis and field surveys the methodology relies on a three dimensional hazard vector whose components include the rockfall kinetic energy the fly height and the annual frequency the values of the first two components are calculated for each location along the slope using the 3d rockfall runout simulator hy stone the rockfall annual frequency is assessed by multiplying the annual onset frequency by the simulated transit frequency the annual onset frequency is calculated through a procedure that combines the extent of unstable areas calculated for 10 different seismic hazard scenarios with different annual frequencies of occurrence and the magnitude relative frequency relationship of blocks as derived from the collected field data for each annual frequency of occurrence the unstable area is calculated as a function of morphometric and earthquake characteristics a series of discriminant analysis models using the rockfall datasets and dems of different resolution 1 and 10 m identified the controlling variables and verified the model robustness in contrast with previously published relationships we show that the slope curvature plays a relevant role in the computation of the unstable area

jurassic magmatism related pb zn w mo polymetallic mineralization in the central nanling range south china geochronologic geochemical and isotopic evidence from the huangshaping deposit abstract the nanling range in south china is characterized by extensive mesozoic magmatism and coeval nonferrous and rare metal mineralization huangshaping is a world class pb zn w mo polymetallic skarn deposit in the central nanling range magmatic rocks occurring in this ore district include quartz porphyry granite porphyry granophyre dacite porphyry and aplite with only the first three granitoids genetically associated with polymetallic mineralization most of the orebodies are constrained within the contact zones as skarn and veins between these granitic stocks and the carbonate wall rocks since the age of the quartz porphyry is still controversial and studies of the dacite porphyry and aplite are absent we focus on these magmatic rocks first la icp ms zircon u pb dating suggests that the crystallization ages of the quartz porphyry dacite porphyry and aplite are 154 3 1 9 ma 158 1 0 8 ma and 148 4 3 4 ma respectively combined with previously published age data we infer the evolutionary sequence of magmatic rocks should be dacite porphyry quartz porphyry granite porphyry granophyre aplite the quartz porphyry dacite porphyry and aplite yield high contents of high field strength elements zr nb ce y 255 440 ppm high ratios of 10 000 ga al 2 6 3 2 and prominent depletions in ba sr eu p and ti indicating their crustal affinities to a type granites they have negative end t values 9 4 to 7 0 and high initial pb isotopic ratios 206pb 204pbi 18 307 18 644 207pb 204pbi 15 689 15 742 208pb 204pbi 38 589 38 986 suggesting that they were probably derived by partial melting of ancient granulitic crustal materials the sulfide minerals exhibit a wide range of 34sv cdt values from 22 6 to 24 2 with 206pb 204pb of 17 669 19 708 207pb 204pb of 15 492 15 714 and 208pb 204pb of 37 880 39 789 indicating that sulfur lead and other associated metals were derived from a mixture of magmatic components and the carboniferous wall rocks fluid inclusions in pyrrhotite sphalerite and marmatite samples have 3he 4he ratios of 0 12 to 1 53 ra with calculated mantle helium proportions of 1 3 to 18 9 indicating a predominantly crustal origin for the ore fluids with minor inputs from the mantle the huangshaping deposit is a typical example of the genetic relationship both spatially and temporally between jurassic magmatism and polymetallic metallogeny in the nanling range

he ar s pb and o isotope geochemistry of the dabaiyang gold deposit implications for the relationship between gold metallogeny and destruction of the north china craton abstract the dabaiyang gold deposit is located within the zhang xuan gold mineralized zone along the northern margin of the north china craton ncc the ore mineralization is hosted within precambrian metamorphic rocks and is a typical quartz vein type gold deposit with minor sulfide mineralization here we report he ar s pb and o isotopes from this deposit with a view to trace the source of the ore forming fluids and metals and to evaluate the relationship among ore formation magmatism and craton destruction in the ncc the ratios of 3he 4he and 40ar 36ar of the fluid inclusions in the pyrite of the dabaiyang ores show a range of 1 4ra 1 8ra and 4974 4 15669 5 respectively with the concentrations of 4he and 40ar varying from 0 8 to 6 6 10 7 cm3 stp g and 4 3 to 218 1 10 7 cm3 stp g respectively our data suggest that mixed mantle and crust derived fluids were involved in the dabaiyang gold mineralization with ca 17 1 27 6 mantle derived helium as computed from crust mantle mixing model the 34s values in the pyrite range from 10 40 to 11 90 with an average of 10 96 suggesting that the sulfur in the ore forming fluids was derived from a mixed source of the precambrian metamorphic basement and mantle the pb isotopic ratios in the pyrite from the ores show 206pb 204pb 207pb 204pb and 208pb 204pb in the range of 16 82 to 17 16 15 33 to 15 43 and 36 77 to 37 22 respectively indicating that the ore forming fluids and by inference the ore metals were mainly derived from lower continental crust with minor contribution of mantle the 18oh2o values of the fluid inclusions in the gold bearing quartz veins range from 1 04 to 4 36 suggesting the dominant role of magmatic water with minor contribution of meteoric water in the ore precipitation based on the analytical results of the isotopic compositions obtained in this study combined with the previously published geochronological and he ar s pb o isotopic data we suggest that the ore fluids and metals were derived from a mixed source involving contributions from mantle crust and atmospheric water and that the ore formation was associated with destruction of the north china craton

simulation of soil erosion and deposition in a changing land use a modelling approach to implement the support practice factor abstract using the usped unit stream power erosion deposition model three land use scenarios were analysed for an italian small catchment 15 km 2 of high landscape value the upper orme stream catchment located in the chianti area 30 km south of florence has a long historical agriculture record information on land use and soil conservation practices date back to 1821 hence offering an opportunity to model impacts of land use change on erosion and deposition for this study a procedure that takes into account soil conservation practices and potential sediment storage is proposed the approach was to calculate and model the flow accumulation considering rural and logging roads location of urban areas drainage ditches streams gullies and permanent sediment sinks this calculation attempts to assess the spatial variability especially the impact of support practices p factor weather data from 1980 2003 were taken into account to calculate the r factor however to consider the intense pluviometric conditions in terms of the erosivity factor the 0 75th quantile was used while the lowest erosivity was modelled using the 0 25th quantile results of the usped model simulation show that in 1821 the mean annual net erosion for the watershed was 2 8 mg ha 1 y 1 in 1954 it was 4 2 mg ha 1 y 1 and in 2004 it was 5 3 mg ha 1 y 1 conservation practices can reduce erosion processes by 20 mg ha 1 y 1 when the 1821 practices are introduced in the present management on the other hand if the support practices are not considered in the model soil erosion risk is overestimated field observation for the present day simulation confirmed that erosion and associated sediment deposition predicted by the model depend as expected on geomorphology and land use the model shows limitations that are mainly due to the input data a high resolution dem is essential for the delineation of reliable topographic potential to predict erosion and deposition especially in vineyards

detecting himalayan glacial lake outburst floods from landsat time series abstract several thousands of moraine dammed and supraglacial lakes spread over the hindu kush himalayan hkh region and some have grown rapidly in past decades due to glacier retreat the sudden emptying of these lakes releases large volumes of water and sediment in destructive glacial lake outburst floods glofs one of the most publicised natural hazards to the rapidly growing himalayan population despite the growing number and size of glacial lakes the frequency of documented glofs is remarkably constant we explore this possible reporting bias and offer a new processing chain for establishing a more complete himalayan glof inventory we make use of the full seasonal archive of landsat images between 1988 and 2016 and track automatically where glofs left shrinking water bodies and tails of sediment at high elevations we trained a random forest classifier to generate fuzzy land cover maps for 2491 images achieving overall accuracies of 91 we developed a likelihood based change point technique to estimate the timing of glofs at the pixel scale our method objectively detected ten out of eleven documented glofs and another ten lakes that gave rise to previously unreported glofs we thus nearly doubled the existing glof record for a study area covering 10 of the hkh region remaining challenges for automatically detecting glofs include image insufficiently accurate co registration misclassifications in the land cover maps and image noise from clouds shadows or ice yet our processing chain is robust and has the potential for being applied on the greater hkh and mountain ranges elsewhere opening the door for objectively expanding the knowledge base on glof activity over the past three decades

geochronological and sulfur isotopic evidence for the genesis of the post magmatic deeply sourced and anomalously gold rich daliuhang orogenic deposit jiaodong china the daliuhang gold deposit 20 t gold is located in the central penglai qixia belt of the giant jiaodong gold province eastern china the ore hosting guojialing granodiorite and pegmatite were formed at 129 0 0 6 ma and 126 2 0 6 ma respectively syn ore monazite with a u pb age of 120 5 1 7 ma represents the timing of gold mineralization given at least 5 m y between magmatism and mineralization a genetic relationship to magmatic hydrothermal activity is negated noble gas isotopes of pyrite have crust mantle mixed 3he 4he 1 13 to 1 50 ra and air like 40ar 36ar 327 574 together with the broadly positive correlation between 3he and 36ar it is inferred that the initial ore forming fluids were deeply sourced from the sedimentary wedge overlying the subducted plate and overlying mantle during early cretaceous paleo pacific plate subduction the pre ore and post ore pyrites have low 34s values 3 7 5 6 and 5 3 6 4 respectively whereas ore related pyrites have higher 34s values especially in as au rich domains 7 8 8 3 these positive 34s values also suggest that the initial ore fluid and some of the sulfur component were derived via subduction related devolatilization the elevated 34s values of the ore related pyrite are partly ascribed to mass fractionation and partly to a contribution from sulfur leached from crustal host rocks this interpretation is also supported by neodymium isotope ratios of monazite end 120 ma 13 7 to 11 6 which correlate well with the ore hosting guojialing granodiorite this study highlights the combined roles of deeply derived fluids and intense interaction with upper crustal rocks in the formation of jiaodong gold deposits

loess in a cave lithostratigraphic and correlative value of loess and loess like layers in caves from the krakow czestochowa upland poland abstract although debris loams and clays are usually regarded as typical cave sediments loess and loess like sediments are common among clastic cave deposits in the near entrance facies of caves and rock shelters late weichselian loess layers are very common in caves from the krakow czestochowa upland and were recognized in almost each excavated cave and rock shelter these layers were initially dated to the lgm last glacial maximum but new chronometric dating results are available that allow us to present a more detailed scheme of the geological age of the series this paper evaluates the significance of polish in cave loess layers as correlative horizons we present the lateral and vertical stratigraphy and lithological variability of cave loesses and their usefulness as lithostratigraphic markers these features are especially important for archeology and paleontology as cave sediments including loess are usually the carriers of archeological and paleontological material

the distribution of basal motion beneath a high arctic polythermal glacier the longitudinal pattern of surface velocity of a large predominantly cold polythermal glacier john evans glacier ellesmere island canada was measured over summer and winter periods inthe accumulation and upper ablationareas where ice is predominantly cold based summer velocities were slightly higher than overwinter velocities predicted velocities due to ice deformation alone in these areas closely matched these observations in the winter with limited basal motion likely in the summer in the lower ablation area where ice is likely warm based measured summer velocities were up to double overwinter velocities predicted ice deformationcould notaccountforall of these measured velocities in either summer or winter this suggests that basal motion occurs throughout the year over at least part of the lower ablation area this finding is supported by radio echo sounding subglacial drainage reconstructions and analyses of early summer meltwater chemistry which suggest that subglacial water is present throughout the year in thisregion insummer basalmotionmayaccountforupto75 ofthetotalsurfacevelocity throughoutthelowerablationarea the inferred rate of basal motionincreasessharplydir ectly below a setof moulinsby which most surface meltwater reachestheglacierbed

mantle crustal and atmospheric noble gases in ailaoshan gold deposits yunnan province china abstract helium and argon isotopic and elemental compositions of fluids released by crushing pyrite grains are reported from the ailaoshan gold province china the province is a series of gold deposits hosted on a 200 km segment of a major normal fault formed during eocene extension the deposits have been well characterised using conventional geochemical and microthermometric techniques the results of which are consistent with a predominantly high temperature magmatic fluid present in the ore minerals in contrast analyses of noble gases from three gold deposits demonstrate the palaeofluids were a mixture between a mantle derived magmatic fluid and two different low temperature fluids similar to modern groundwaters the specific isotopic and abundance characteristics of helium and argon allow unequivocal identification of both a mantle derived component and a surface derived component to these fluids the magmatic fluid dominates deposits from the northern end of the fault the second groundwater is present only in deposits in the south of the province by assuming fluid inclusion homogenisation temperatures in coexisting quartz are representative of fluid temperature 3he heat ratios can be estimated the 3he heat ratios vary systematically along the fault from 30 10 12 cm3 stp j 1 in the northern deposits to

noble gases in pyrites from the guocheng liaoshang gold belt in the jiaodong province evidence for a mantle source of gold abstract the recent mineral exploration programme 2009 2014 in the jiaodong gold province identified the new guocheng liaoshang gold metallogenic belt which contains reserves of 92 tonnes t au in the main deposits the ore is fault hosted in massive sulfides that make up to 25 to 95 vol the he ar isotope compositions of ore forming fluids from 20 pyrite samples from the five main deposits are reported here 3 he 4 he range between 0 41 and 2 39 r a 40 ar 36 ar are 367 to 2112 and 40 ar 4 he are 0 40 3 78 the data require four gas sources a dominant mantle derived component plus sub ordinate crustal radiogenic meteoric and basin brine components the mantle end member has 3 he 4 he 3 32 4 00 r a this is lower than most estimates for sub continental lithospheric mantle sclm 6 7 r a implying that it was probably refertilized by subduction related fluid metasomatism this is consistent with he ar isotopes reported for sclm xenoliths from basalts in the shandong province within the mineralisation province the mine au reserve is positively correlated with the proportion of mantle derived he in the ore forming fluids this implies that the fluids and by inference the gold was largely derived from mantle melts during lithospheric extension given the conspicuous association of gold ore deposits with mantle derived magma in the jiaodong peninsula we envisage that our genetic model can be applied to some extent to evaluate the potential of some mineral exploration targets

the loess palaeosol sequence in the upper palaeolithic site at krakow spadzista a palaeoenvironmental approach abstract the krakow spadzista open air site situated in the loess belt in southern poland belongs to the best known gravettian sites of europe many years of archaeological studies revealed a wealth of faunal remains especially mammoths as well as numerous aurignacian gravettian and epigravettian stone artefacts in several cultural layers field pedogeomorphological investigations 2011 2012 and laboratory analyses geochemical granulometric micromorphological palynological and irsl dating were the basis for palaeogeographical discussion on the conditions of the loess soil sequence development five independent litho and pedological units corresponding to mis 5 to 2 were distinguished primary loess layers are relatively thin and contain many hiatuses diverse structure and development of intra loess palaeosols reflect their origin age and stratigraphic rank the cultural layers were found in weakly developed soils with the traces of subsequent periglacial mainly deluvial solifluction transformations of different intensity the palaeosols represent two periods of interglacial rank eemian forest palaeosol and the overlying postglacial modern soil mis 5 and 1 respectively and two interstadials subarctic soils with the gravettian artefacts mis 3 one weakly developed gleyic horizon with the features of tundra soil occurs within the loess corresponding to climatic pessimum of weichselian glaciation mis 2 in the very local promontory with the site and micro regional sowiniec horst scales the distinguished soils are undoubtedly important palaeogeographical and archaeological key horizons

extraction of multi scale landslide morphological features based on local g i using airborne lidar derived dem abstract for automatic landslide detection landslide morphological features should be quantitatively expressed and extracted high resolution digital elevation models dems derived from airborne light detection and ranging lidar data allow fine scale morphological features to be extracted but noise in dems influences morphological feature extraction and the multi scale nature of landslide features should be considered this paper proposes a method to extract landslide morphological features characterized by homogeneous spatial patterns both profile and tangential curvature are utilized to quantify land surface morphology and a local gi statistic is calculated for each cell to identify significant patterns of clustering of similar morphometric values the method was tested on both synthetic surfaces simulating natural terrain and airborne lidar data acquired over an area dominated by shallow debris slides and flows the test results of the synthetic data indicate that the concave and convex morphologies of the simulated terrain features at different scales and distinctness could be recognized using the proposed method even when random noise was added to the synthetic data in the test area cells with large local gi values were extracted at a specified significance level from the profile and the tangential curvature image generated from the lidar derived 1 m dem the morphologies of landslide main scarps source areas and trails were clearly indicated and the morphological features were represented by clusters of extracted cells a comparison with the morphological feature extraction method based on curvature thresholds proved the proposed method s robustness to dem noise when verified against a landslide inventory the morphological features of almost all recent 10 years landslides were extracted this finding indicates that the proposed method can facilitate landslide detection although the cell clusters extracted from curvature images should be filtered using a filtering strategy based on supplementary information provided by expert knowledge or other data sources

zircon inclusions in corundum megacrysts i trace element geochemistry and clues to the origin of corundum megacrysts in alkali basalts abstract zircons enclosed in corundum megacrysts from basalts have a short prismatic habit with the prism slightly more developed than the pyramidal faces the 110 prism is dominant compared with 100 indicating crystallisation from alkaline peralkaline environments rare zircon decomposition reactions suggest the possible presence of a primary sio 2 phase in the source paragenesis for corundum megacrysts the zircon inclusions are geochemically distinctive high y up to 1 2 u uo 2 up to 1 7 wt th tho 2 up to more than 2 wt hf up to 3 4 wt and ree ree up to 5000 ppm they form a cogenetic group that is characterised by extreme ree fractionation with preference for the hree varying from 30 100 chondritic sm to 5000 20000 chondritic lu ree partitioning between zircon and silicate liquid is evaluated the parental melts calculated for the zircon inclusions and other corundum related zircons using zircon melt partition coefficients derived in the present paper show concave down ree patterns with a maximum sm concentration close to 100 chondritic sm abundance such ree patterns represent highly evolved melts after extensive fractionation of low ca feldspar prior to and throughout the crystallisation of zircon the characteristics of zircon inclusions provide evidence that corundum megacrysts must have crystallised from alkaline and highly evolved melts under very reducing conditions implying that the corundum is unlikely to have formed as high pressure phenocrysts in the host mafic magmas

he ar and s isotopic compositions and origin of giant porphyry mo deposits in the lesser xing an range zhangguangcai range metallogenic belt northeast china abstract the lesser xing an range zhangguangcai range metallogenic belt located at the eastern segment of the central asian metallogenic domain hosts two giant mo porphyry deposits the early jurassic luming deposit and the middle jurassic daheishan deposit in this study the he ar and s isotopic compositions of sulfides from different hydrothermal stages of the daheishan and luming deposits were determined fluid inclusions hosted in pyrites shown that 3he 4he ratios of the luming and daheishan deposit range from 0 02 to 0 32 ra and 0 7 to 2 5 ra respectively 40ar 36ar ratios of the luming and daheishan deposit range from 313 3 to 535 1 and 309 9 to 360 6 respectively he and ar isotopic compositions suggest that the ore forming fluids of the luming deposit are mainly crustal derived fluids with near atmospheric ar and crustal he values mantle derived fluids are a minor component in contrast the ore forming fluids of the daheishan deposit are a mixture between a crust derived fluid and a mantle derived fluid the 34s values of the sulfide samples from the luming deposit 4 98 7 14 and the daheishan deposit 1 83 2 88 indicate that the sulfur in the ore forming fluids was primarily derived from granitic magma the isotopic compositions across the stages within one deposit have no variability the similar he ar and s isotopic compositions of the sulfides from the different mo bearing hydrothermal stages of these two giant mo deposits indicate that the overprinting of the multiple stages of mo bearing hydrothermal fluids may be a key factor in the formation of giant porphyry mo deposits meanwhile the westward subduction of the paleo pacific plate might have played an important role for the formation of the giant mo deposits in the lesser xing an range zhangguangcai range metallogenic belt

resolving mantle and crustal contributions to ancient hydrothermal fluids hear isotopes in fluid inclusions from dae hwa wmo mineralisation south korea abstract helium and argon isotopes from fluid inclusions in individual colour zones b c d and e of a large scheelite crystal from the 88 ma dae hwa w mo deposit south korea trace the source and history of the ore fluids a gradual decrease of the fluid 3 he 4 he 3 he 36 ar and 40 ar 36 ar from the core to the edge of the scheelite reflects the progressive dilution of a magmatic fluid by meteoric water and is consistent with the previously observed decrease of 18oh2o and fluid inclusion homogenisation temperatures th shelton et al 1987 the covariation of fluid inclusion he ar isotope systematics with 18o and th defines a magmatic component with 3 he 4 he 1 2 10 6 3 he 36 ar 0 01 and 40 ar 36 ar 1000 anomalously high helium and argon isotope ratios in zone d fluids represents undiluted magmatic noble gases this may reflect local variation in the magmatic gas flux or gas loss due to boiling of the hydrothermal fluids prior to mixing with magmatic gas helium and argon isotope systematics constrain mantle and crustal components in the hydrothermal fluids 40 ar 3 he 4 5 104 are close to the mid ocean ridge basalt value implying that 40ar is mantle in origin radiogenic isotope ratios of the mantle endmember 40 ar 4 he 0 69 0 06 are similar to contemporary geothermal fluids the coincidence of mantle derived he and ar in the fluids is strong evidence that mantle melting during late cretaceous subduction triggered the crystal melting responsible for granite formation 40 ar 4 he of the meteoric fluid 0 007 0 001 is far lower than the crystal production ratio 0 2 implying an origin in crust below 200 c

auriferous pyrite re os geochronology and he ar isotopic compositions of the jinchangyu au deposit in the northern margin of the north china craton abstract the jinchangyu au deposit is the largest quartz vein gold deposit in eastern hebei province china in the northern margin of the north china craton nmncc three mineralization stages are identified based on crosscutting relationships and mineral assemblages with au occurring mainly in pyrites in quartz sulphide veinlets and quartz albite veins five low level highly radiogenic pyrite samples in the quartz sulphide veinlets yielded a re os isochron age of 223 5 6 0 ma auriferous pyrite he ar isotopic analyses indicate that the ore forming fluid was a mixture of mantle derived and crustal fluids 3he 4he ratios are in the range 1 72 3 92 ra corresponding to 22 50 mantle he contribution these high 3he 4he ratios are related to lithospheric thinning in the nmncc during the middle late triassic with initial thinning during that period being supported by the wide distribution of indosinian au deposits and the regional tectonic and magmatic evolution the mineralization of the jinchangyu deposit and of other similar triassic deposits was a response to post orogenic to intraplate lithospheric extension after collision between the ncc and the southern margin of the siberian plate

recycled noble gases preserved in podiform chromitites from luobusa tibet abstract we report noble gas he ne ar signatures of chromite and olivine separates from the luobusa chromitites in tibet to better understand the volatile compositions trapped in the minerals and further to trace the origin of melts responsible for formation of the chromite deposits the studied samples can be divided into two groups based on petrography and distinct noble gas signatures group i samples are free of carbonates and have 3he 4he ratios from 0 81 to 2 36 ra where ra is the 3he 4he ratio of air 1 4 10 6 and air like ne and ar isotopic compositions irrespective of chromitite structure types most 3he 4he ratios of group i samples are higher than air suggesting apparent presence of mantle volatiles given the 4he 20ne and 3he 36ar several orders of magnitude higher than air negligible contributions are from the atmospheric helium the observed he isotope compositions thus can be regarded as a two component mixture of mantle derived and radiogenic he a broadly positive correlation between 3he and 36ar in nodular chromitite samples indicates a source mixing between mantle and recycled noble gases but not due to shallow air contamination in addition the wide distribution range of 20ne 36ar also supports a subduction related origin of neon and argon combined with major element data the most appropriate tectonic setting to generate such noble gas signatures in group i samples is subduction zone probably forearc where favorable conditions are present for the formation of the chromitites in contrast group ii samples containing carbonates have much more radiogenic 3he 4he ratios of 0 03 to 0 3 ra but much less radiogenic 40ar 36ar ratios of 344 to 420 in combination with the occurrence of carbonate veins it is suggested that group ii samples are predominated by supracrustal components that may be imparted during or after the emplacement stage a comparison of these two group samples indicates that the primary noble gas signatures reflecting the characteristics of ore forming melts can be preserved in chromite and olivine grains group i samples and thus used to trace the origin of podiform chromitites

burning wood or burning bone a reconsideration of flotation evidence from upper palaeolithic gravettian sites in the moravian corridor abstract this paper compares archaeobotanical and other data from new excavations at two upper palaeolithic sites dolni v stonice ii and p edmosti i in the moravian corridor czech republic both contain the traces of broadly contemporary gravettian occupations during the warmer episodes of the pleistocene which preceded the last glacial maximum yet their archaeobotanical remains show striking differences those from dolni v stonice ii being dominated by large quantities of conifer wood charcoal while those from p edmosti i are much more scanty and dominated by vitrified plant remains in association with large quantities of burnt bone we argue that these differences between these two datasets arise from different uses of fuel at either site bone at p edmosti i and wood at dolni v stonice ii subsequently we explore the possible reasons for this difference and argue that once likely taphonomic distinctions are accounted for these data on fuel use offer fresh insights into the functions and durations of these upper palaeolithic occupations of the moravian corridor and some possible implications for how archaeobotanical data from such sites should be interpreted

exploring the effect of absence selection on landslide susceptibility models a case study in sicily italy abstract a statistical approach was employed to model the spatial distribution of rainfall triggered landslides in two areas in sicily italy that occurred during the winter of 2004 2005 the investigated areas are located within the belice river basin and extend for 38 5 and 10 3 km 2 respectively a landslide inventory was established for both areas using two google earth images taken on october 25th 2004 and on march 18th 2005 to map slope failures activated or reactivated during this interval geographic information systems gis were used to prepare 5 m grids of the dependent variables absence presence of landslide and independent variables lithology and 13 dem derivatives multivariate adaptive regression splines mars were applied to model landslide susceptibility whereas receiver operating characteristic roc curves and the area under the roc curve auc were used to evaluate model performance to evaluate the robustness of the whole procedure we prepared 10 different samples of positive landslide presence and negative landslide absence cases for each area absences were selected through two different methods i extraction from randomly distributed circles with a diameter corresponding to the mean width of the landslide source areas and ii selection as randomly distributed individual grid cells a comparison was also made between the predictive performances of models including and not including the lithology parameter the models trained and tested on the same area demonstrated excellent to outstanding fit auc 0 8 on the other hand predictive skill decreases when measured outside the calibration area although most of the landslides occur where susceptibility is high and the overall model performance is acceptable auc 0 7 the results also showed that the accuracy of the landslide susceptibility models is higher when lithology is included in the statistical analysis models whose absences were selected using random circles showed a significantly better performance when learning and validation samples were extracted from the same area whereas conversely no significant difference was observed when testing the models outside the training area

variability of late gravettian lithic industries in southern poland a case study of the krakow spadzista and jaksice ii sites this article summarizes archaeological data obtained from two late gravettian assemblages discovered at krakow spadzista and jaksice ii sites at the krakow spadzista site different tool types in each zone were discovered what could be a reflection of the varied activities carried out on each part of the site from the other hand at jaksice cite a homogeneous lithic assemblage with a predominance of the armatures was discovered these two inventories differ fundamentally both in terms of the raw materials used tool making technologies as well as the lithic typology and morphology these dissimilarities could be observed not only between above mentioned sites but also among other late gravettian localities known from central europe and they concern primarily retouched tool assemblages this leads us to conclude that in this period we could observe a mosaic of dissimilar inventories but at least at the current stage of research they do not define any group of sites either geographically or chronologically whether this is the reflection of cultural diversity or seasonally varied assemblages used by palaeolithic hunter gatherers we can not unriddle we could only state that the problem is most complicated and needs more detailed studies focused not only on the lithic artefacts but also on faunal remains chronology and paleoenvironmental reconstruction only the correlation of all this data can bring us closer to solving the problem of the diversification of the late gravettian industries

predictive modeling of bedrock outcrops and associated shallow soil in upland glaciated landscapes abstract identifying the areal extent of bedrock outcrops and shallow soils has important implications for understanding spatial patterns in vegetation composition and productivity stream chemistry gradients and hydrologic and soil properties of landscapes manual methods of delineating bedrock outcrops and associated shallow soils are still commonly employed but they are expensive to implement over broad areas and often limited by representation of polygon units few studies have automated the delineation of bedrock outcrops these focused on delineation approaches in landscapes with rapidly eroding hillslopes and sparse vegetation the objectives of this study were to assess the accuracy of visually interpreting high resolution relief maps for locating bedrock outcrops and associated shallow soil boss

noble gas isotopes in corundum and peridotite xenoliths from the eastern north china craton implication for comprehensive refertilization of lithospheric mantle abstract noble gas isotopic ratios provide unique and important constraints for the evolution of the subcontinental mantle we present one step crushing noble gas isotope data from corundum and co existing mantle xenoliths and megacrystals from the changle volcanic fields in the middle part of the tan lu fault zone eastern north china craton the 3he 4he ratio is 7 6 8 3 times the atmospheric ratio ra in corundum indicating contributions of fluids from convective asthenosphere the 3he 4he ratio in titanomagnetite megacrystals ranges from 5 8 to 6 5 ra suggesting possible u th contamination in the crystal lattice with the 3he 4he ratio of host magma being higher than 6 5 ra the olivine and opx in lherzolite show high helium contents and homogeneous isotopic helium ratios 6 9 7 0 ra the cpx in wehrlite show significantly higher helium contents and slightly higher helium ratio 7 6 ra than co existing olivine 7 0 7 5 ra combined with isotope correlation diagrams the systematic difference in 4he abundance the 3he 4he and 4he 40ar ratios of cpx opx and olivine in pyroxenite lherzolite and wehrlite suggest comprehensive refertilization of lithospheric mantle in the eastern north china craton

quantitative analysis of land surface topography land surface topography significantly affects the processes of runoff and erosion a system which determines slope aspect and curvature in both the down slope and across slope directions is developed for an altitude matrix also the upslope drainage area and maximum drainage distance are determined for every point within the altitude matrix a fortran 66 program performs the analysis

the beiminghe skarn iron deposit eastern china geochronology isotope geochemistry and implications for the destruction of the north china craton article i nfo the beiminghe bmh iron ore in the southern part of the taihang mountain tm hebei province is one of the largest skarn iron deposits in china here we report phlogopite 40 ar 39 ar and zircon u pb age data as well as sulfur lead and he ar isotope geochemistry of pyrite from the ores and skarnitized rocks in the deposit in an attempt to constrain the timing and mechanism of formation of the mineralization the phlogopite 40 ar 39 ar and la icp ms zircon u pb data show markedly consistent ages constraining the timing of ore formation as 136 137 ma the presence of several inherited zircons with late archean or paleoproterozoic ages indicates the participation of the basement rocks during the ore forming process the 34 sv alues of pyrite from the ores range from 12 2 to 16 5 with 206 he 0 036 0 421 the mesozoic magmatism and metallogeny in the bmh correlate well with the peak event of lithospheric thinning and destruction of the north china craton during this process the early precambrian lower crustal rocks in the region were re melted through underplating of mantle magmas leading to the forma tion of the beiminghe monzodioritic pluton minor mantle input occurred during the evolution of the monzodiorite magma which scavenged the ore forming materials from the lower crust interaction of the magmas and fluids with the surrounding rocks resulted in the formation of the beiminghe skarn iron deposits the magmatism and metallogeny in the taihang mountain are signatures of the extensive craton destruction and lithospheric thinning in the eastern part of the north china craton during mesozoic probably associated with pacific slab subduction

glacial geomorphology and geographic information systems recent developments in the field of glacial geomorphology have dramatically increased the need to acquire maintain manipulate and analyze large amounts of landform landscape and sediment data the use of geographic information systems gis has provided new platforms and tools for analysis and visualization of geomorphic data glacial geomorphologists have used gis to integrate multi source data manage multi scale studies identify previously unrecognized spatial and temporal relationships and patterns in geomorphic data and to link landform data with numerical models as part of model calibration and verification gis based analyses associated with numerical modeling are improving our understanding of glacial landscape evolution and are allowing new quantitative and systematic examinations of spatial and temporal patterns of glacial landforms and processes this has allowed for the development of insights and concepts that would be unlikely to arise using traditional methods alone key recommendations for future research and applications in glacial geomorphology include enhanced gis education and dissemination the development of standards and conventions for glacial geomorphic data community projects to collect data into readily accessible databases and enhanced use of linked gis model frameworks to address major issues in glacial geomorphology