a stable isotope study of cave seepage waters an isotope study 18o 2 h of 62 samples of waters from both the interior of the nerja cave malaga southern spain and the exterior sinkholes and springs at the site was carried out rainfall water in the study area was also studied the mean value of seepage waters can be considered as the mean isotopic value of the precipitation waters of the area the origin and aquifers of these different types of waters has also been studied obtaining a clear meteoric origin both for the seepage waters and the waters from the wells and springs but the aquifer of the latter is different showing more negative isotopic values this suggests that they could have mixed with waters from other aquifers which are either deeper or originate at other altitudes

calibration of conodont color alteration using color image analysis a set of 40 polished sections of silurian and devonian conodonts with color alteration indices ranging from 1 0 to 8 0 was examined using color image analysis the color composition of each conodont specimen was determined by measuring the intensities of the red green and blue color components on several carefully selected areas the data were evaluated using nested analysis of variance the observed variance can be attributed to three different sources of error within the studied conodont population the variance due to rank amounts to an average 90 the variance due to taxonomic differences or type of conodont element is about 3 and thus of minor importance the heterogeneity within single specimens amounts to 6 and is also a minor source of variance the application of color image analysis helps characterize samples of different rank but similar optical properties color image analysis helps reduce the subjectivity of conodont color alteration studies

apollo 16 impact melt sheets contrasting nature of the cayley plains and descartes mountains and geologic history apollo 16 stations 4 and 5 rake samples were examined petrographically and by electron microprobe and inaa results were combined with published information major and trace element compositions petrologic information and age determinations for nonrake samples from stations 4 and 5 and some other apollo 16 sample localities lithologic abundances support the idea korotev 1981 that the variation of soil compositions at apollo 16 is a result of mixing between a component represented by station 5 soil and components much like either the dimict breccias station 4 soils or feldspathic fragmental breccias stations 1 2 and 11 in composition dimict breccias because of their restricted occurrence are apparently not a constituent of either the cayley or descartes formations they were contributed to the surface materials by south ray crater and were probably excavated from beneath both formations by this event pyroxene olivine and coexisting plagioclase compositions from within the anorthosite portions of dimict breccias bridge the gap between the mg rich and ferroan anorthosite fields analyses from associated cumulate and granulitic clasts indicate that they are the source of the intermediate material dimict breccia anorthosites are thus polymict rocks not pristine ferroan anorthosite compositions of apollo 16 impact melt rocks suggest a number of compositional clusters discriminant and cluster analyses of compositional data confirm the existence and strength of these clusters as do age determinations and ir au ratios within each group each of three clusters represents an impact event in the apollo 16 region petrologic information and age determinations indicate that dimict breccias formed approximately 3 92 b y ago the nectaris event occured between 3 84 and 3 92 b y ago and the cayley plains were deposited as a result of the imbrium event sometime later than 3 84 b y

oxygen and hydrogen isotopic variations between adjacent drips in three caves at increasing elevation in a temperate coastal rainforest vancouver island canada abstract the interpretation of speleothem paleoenvironmental records requires understanding of spatial temporal variations in vadose drip water chemistry and isotopic composition this study reports on intra and inter cave differences in d 18o and electrical conductivity using 18 monthly water samples from three adjacent drips all drips showed isotopic seasonal signals despite varied patterns of drip hydrology there was overlap in isotopic ranges at 1 sd between all three caves in contrast with the expected 18o depletion of 0 15 to 0 5 100 m of ascent observed in standard precipitation the isotopic seasonality was approximated with sine curves and compared to a gnip data set from victoria 300 km to the south the d and 18o drip isotopes lagged the victoria record by 155 26 days and 165 50 days respectively the longest lag was at the slowest drip sea level while the shortest lag 87 days for 18o 550 m asl implies a short residence time paradoxically from the drip with the highest mean electrical conductivity vadose residence time was less than one climatic year reflecting a combination of negligible matrix porosity in the host rock and super humid climatic conditions beneath the epikarst drip hydrology was evidently by simple piston flow phase shifted drip isotope records showed excellent agreement with sea level mean monthly air temperatures at the tahsis meteorological station over the study period the d and 18o drip amplitudes were damped on average 74 and 73 respectively compared to the victoria data the drips at 740 m asl are tightly aligned to the global mean meteoric water line gmwl and 18o depleted the drips at 550 m asl and at sea level plot along the gmwl or between it and the victoria lmwl with the exception of the slowest drip sea level which displays some seasonal evaporitic enrichment the findings quantify substantial intra and inter cave variation of d and 18o in drips having a wide range of drip type and volume of flow sufficient to mute the altitudinal isotopic lapse rate in this local coastal rainforest environment

quantitative spore colour measurement using colour image analysis abstract the colour changes that spores exhibit with increasing depth of burial are used as a thermal maturity indicator for evaluating hydrocarbon source rocks spore colour is determined visually leading to an intrinsic difficulty of unequivocally assessing and recording their colour quantitative scales using photometers are available but are not widely applied colour image analysis cia is presented here as an alternative method for the quantification of spore colour through the use of image analysis software common in many laboratories using the rgb red green blue colour format the colour of spores was determined the material included a set of artificially heated lycopodium spores and geological samples from a range of ages and geographical areas covering the entire maturity range these data were then compared to samples from a well section of carboniferous age which were fully mature to post mature with increasing maturity the colour changes in spores and pollen define a consistent and reproducible trend on the red vs green pixel intensity graph significantly all samples suites experimental and natural exhibit the same behaviour previous research milton 1993 ph d thesis gutjahr 1966 leidse geologische medelingen 38 1 30 show a strong morphological control on colour based on differences in wall thickness and original chemistry however if spores and pollen are chosen carefully i e avoiding taxon with cracks folds apertures and ornamentation as well as those with exceptionally thin bag type or thick exines a good sample average can be made by measurement of 40 50 similar spore pollen types specific points on the red vs green colour graph coincide with significant chemical transformations and these coincide with the thermal cracking of the spore wall spore oil window

organic facies and palynofacies nomenclature classification and applicability for petroleum source rock evaluation abstract the basic aim of the investigation presented in this paper was to determine all relevant petrographical and geochemical characteristics of organic facies and their correlation with the lithological composition sedimentation conditions and paleoenvironments application of geological and geochemical methods gives new insight into problems concerning determination of the potential and efficiency of petroleum source rocks in making the qualitative and quantitative analyses of organic matter in this study various analytical methods were used whole rock samples kerogen concentrates transmitted and reflected normal and fluorescent light the type of organic facies was used as a criterion for the identification accumulation and transformation of the organic matter paleobotanical studies of organic facies and palynofacies were used to identify types of vegetation and draw conclusions concerning the sedimentary environment various types of organic facies and palynofacies were classified in relation to the origin of the organic matter all sedimentary organic constituents of continental huminite vitrinite inertinite cuticle wood fragments tracheids spores and pollen and marine mostly autochthonous dinocysts algae foraminifera test linings acritarchs and amorphous organic matter origin have been grouped according to different classification systems a summary of these classifications is proposed with remarks on approximate corresponding coal macerals and selected kerogen types

hydrological change in southern europe responding to increasing north atlantic overturning during greenland stadial 1 greenland stadial 1 gs 1 was the last of a long series of severe cooling episodes in the northern hemisphere during the last glacial period numerous north atlantic and european records reveal the intense environmental impact of that stadial whose origin is attributed to an intense weakening of the atlantic meridional overturning circulation in response to freshening of the north atlantic recent high resolution studies of european lakes revealed a mid gs 1 transition in the climatic regimes the geographical extension of such atmospheric changes and their potential coupling with ocean dynamics still remains unclear here we use a subdecadally resolved stalagmite record from the northern iberian peninsula to further investigate the timing and forcing of this transition a solid interpretation of the environmental changes detected in this new accurately dated stalagmite record is based on a parallel cave monitoring exercise this record reveals a gradual transition from dry to wet conditions starting at 12 500 y before 2000 a d in parallel to a progressive warming of the subtropical atlantic ocean the observed atmospheric changes are proposed to be led by a progressive resumption of the north atlantic convection and highlight the complex regional signature of gs 1 very distinctive from previous stadial events

monitoring of selected caves as a prerequisite for the speleothem based reconstruction of the quaternary environment in croatia abstract quaternary palaeo environmental changes that have taken place in croatia are likely to be recorded in speleothems secondary carbonate deposits precipitated in caves confident interpretation of well dated speleothem proxy records relies on modern monitoring programs which we provided in three regionally different caves parallel monitoring of the surface and cave air temperature and relative humidity precipitation and cave drip intensity as well as stable isotope modification of meteoric and drip water was carried out in order to estimate the most reliable stalagmites for the interpretation of quaternary landscape history in all three caves nova grgosova 239 m a s l t cave 11 2 c in central croatia lokvarka 780 m a s l t cave 7 5 c in the mountainous part of croatia and modric 32 m a s l t cave 16 6 c in coastal croatia we selected the parts of the caves where the ambient cave conditions appeared to be appropriate for equilibrium deposition of calcite in terms of constant air temperature seasonal amplitudes of 0 73 0 38 and 0 45 c respectively and relative humidity 100 both atlantic and mediterranean moisture influences were detected in all three caves but of different intensities cave hydrological settings governed by karst aquifer properties were resolved by the comparison of the precipitation intensities and drip site responses to the rain events and generally seasonal rainwater isotopic signal was almost completely attenuated except for one drip site such homogenized drip water and stable cave environmental settings give confidence for calcite deposition under equilibrium conditions especially for modric and nova grgosova caves where speleothems inner structures also look promising for potentially quality dating results and stable isotopic profiles the fracture flow drip regime of selected drip sites in lokvarka cave and uncompleted homogenization of the water in the epikarst might point to speleothem samples that are unsuitable for resolving multi annual quaternary climate changes this view is supported by the high porosity internal structure of some lokvarka speleothems so further monitoring sampling and the thorough speleothem examination is therefore necessary for adequate interpretations of palaeo environmental changes

understanding the lunar surface and space moon interactions the surface of the moon is a critical boundary that shapes our understanding of the moon as a whole all geologic mapping and remote sensing techniques utilize only the outermost portion of the moon before leaving the moon for study in our laboratories all lunar samples that have been studied existed at or very near the surface with the exception of the deeply probing geophysical techniques our understanding of the interior of the moon is derived from surficial but not superficial information coupled with boundary of the lunar crust it is the lower boundary layer of the tenuous lunar atmosphere and constitutes both a source and a sink for atmospheric gases the surface is also where the moon interacts with the space environment causing changes in the physical nature of lunar materials and provides a laboratory for the study of processes that occur on all airless bodies the data obtained remotely by the galileo clementine and lunar prospector missions as well as data derived from lunar meteorites have resulted in major changes to our understanding of global distributions of chemistry and rocks this chapter summarizes the current understanding of this critical interface the surface of the moon in its role as the lower boundary of the lunar atmosphere the upper boundary of the crust and the window through which we view through remote sensing the composition of the crust and the history of the moon in this post lunar prospector time the view of the moon has changed lending new perspectives to lunar samples and lunar processes but the new view will likely remain in flux as we continue to digest the results from these recent space missions and move forward to a new era of lunar exploration despite the freshness of our perspective this is an important moment to capture

the other isotopes research avenues based on 36ar 37ar and 38ar the earliest publications on 40 ar 39 ar dating recognized the usefulness of 39 ar 37 ar in providing chemical clues to the species releasing argon during stepped heating while 37 ar measurements are required for interference corrections aside from these essential roles 36 ar 37 ar and 38 ar have other useful applications the dominance of ca as the target nucleus for the production of 38 ar and 36 ar from spallation by cosmic rays has led to the determination of cosmic ray exposure ages from 38 ar 37 ar 38 ar production from cl has an important role in the study of ore minerals containing saline fluid inclusions both in dating and in understanding theirgenesis combining 38 ar 36 arratioswith micro thermometricdeterminations ofsalinity pro vides a way to determine absolute concentrations of noble gases in ore fluids absorption of cosmic ray produced secondary neutrons by 35 cl and 37 cl provides another means to study cosmic ray exposure of meteorites 36 s excesses in meteoritic sodalite provide evidence of now extinct 36 cl in the early solar system surprisingly there is little or no evidence of excess 36 ar beyond what can be accounted for by secondary neutron exposure we have recently devised a method to identify monoisotopic 36 ar from 36 cl decay

early holocene humidity patterns in the iberian peninsula reconstructed from lake pollen and speleothem records abstract comparison of selected well dated lacustrine speleothem and terrestrial pollen records spanning the holocene onset and the early holocene ca 11 7 8 cal kyrs bp in the iberian peninsula shows large hydrological fluctuations and landscape changes with a complex regional pattern in timing and intensity marine pollen records from alboran the mediterranean and off shore atlantic sites show a step wise increase in moisture and forest during this transition however available continental records point to two main patterns of spatial and temporal hydrological variability i atlantic influenced sites located at the northwestern areas enol sanabria lucenza prd 4 characterized by a gradual increase in humidity from the end of the younger dryas to the mid holocene similarly to most north atlantic records and ii continental and mediterranean influenced sites laguna grande villarquemado fuentillejo padul estanya banyoles salines with prolonged arid conditions of variable temporal extension after the younger dryas followed by an abrupt increase in moisture at 10 9 cal kyrs bp different local climate conditions influenced by topography or the variable sensitivity gradual versus threshold values of the proxies analyzed in each case are evaluated vegetation composition conifers versus mesothermophilous taxa and resilience would explain a subdued response of vegetation in central continental areas while in mediterranean sites insufficient summer moisture availability could not maintain high lake levels and promote mesophyte forest in contrast to atlantic influenced areas comparison with available climate models greenland ice cores north atlantic marine sequences and continental records from central and northern europe and the whole mediterranean region underlines the distinctive character of the hydrological changes occurred in inner iberia throughout the early holocene the persistent arid conditions might be explained by the intensification of the summer drought due to the high seasonality contrast at these latitudes caused by the orbital induced summer insolation maximum new records particularly from western and southernmost iberia and palaeoclimate models with higher spatial resolution would help to constrain these hypotheses

isotopic characterization of cave environments at varying altitudes on the eastern adriatic coast croatia implications for future speleothem based studies abstract an important step in the implementation of paleoclimate reconstructions from speleothems cave carbonate deposits is to evaluate the sensitivity of the host cave environment to regional climate accordingly we studied three caves at different altitudes 74 m 570 m and 1250 m a s l along a transect from the dalmatian islands to velebit mountain peaks in coastal croatia to characterize their environments in terms of each cave s suitability to host speleothems that would be capable of yielding robust paleoclimate reconstructions we conducted cave microclimate 2 years and dripwater 1 year monitoring and analysed the isotopic composition of precipitation cave dripwater and modern spelean calcite as for the water isotopic imprints the isotopic values of meteoric waters reaching the two lower altitude caves in spite of an altitude difference of 500 m lie on local meteoric water lines lmwls of similar slope and intercept 2 h 6 61 18 o 4 92 and 2 h 6 69 18 o 6 86 their slopes lower than that of gmwl indicate enhanced evaporation during the warm season as expected the lmwl of the highest cave region 2 h 7 83 18 o 14 45 resembles the slope of the gmwl but the values of deuterium excess obtained for all three caves between 15 2 and 16 6 match that of western mediterranean sourced waters 15 monthly d excess values suggest atlantic sourced air masses can reach the sites throughout the year but never dominate the rainfall composition the altitude effect was noted both in precipitation and in dripwater isotopic composition but with notably different 18 o 100 m gradients 0 33 and 0 11 respectively stable isotope variations of the dripwaters in all caves were attenuated in relation to the rainwater even those of the drip sites with fracture flow behaviour based on stable cave microclimate conditions relatively steady discharges and modern calcite apparently precipitated at or close to isotopic equilibrium with dripwater the two caves at lower altitudes show the greatest potential for future paleoclimate studies the cave at the highest altitude experiences large cave air temperature amplitudes 5 3 c and pronounced ventilation making the isotopic signal susceptible to kinetic fractionation which might preclude quantification of environmental changes but on the other hand it accentuates isotopic events making them easier to identify

millennial scale precipitation changes in southern brazil over the past 90 000 years 1 a u th dated 90 000 year long speleothem oxygen isotope record from southern brazil anti correlates remarkably with the cave calcite records from eastern china but positively correlates with the speleothem record from northeastern brazil suggesting an interhemispheric anti phasing of rainfall on both millennial and orbital timescales likely related to displacement in the mean position of the intertropical convergence zone and associated asymmetry in hadley circulation the phase relationships among these records are consistent with the hypothesis that abrupt climate events during the last glacial period are triggered by oceanic circulation changes in the high latitudes and enhanced by tropical feedbacks

digital quantification of the miospore coloration to assess the thermal maturity novel rgb based measuring technique abstract the post depositional thermal maturity and its related chemical changes induce the sporomorphs color alteration which is a common useful tool in the optical microscopy of the organic matters om and their pre geochemical studies the present contribution uses the modern available opportunity of digital technology to achieve a quantifying system technique which includes color measurements and their possible graphic presentation the normal digital images of sporomorphs from several ages and geological settings are used to obtain color measurements in the form of digital red green and blue triple color system rgb these measurements were accomplished using some software programs such as photoshop or imagej with employing average microscope setup the triple rgb color readings are plotted on a ternary diagram which is divided into three fields these fields express the maturity levels the presented new rgb based quantifying technique is economic and provides a simple examination for maturity which is linked to the hydrocarbon generation this can partially replace or walk side by side with the vitrinite reflectance microscopy

source rock potential and paleoenvironment of the miocene rudeis and kareem formations gulf of suez egypt an integrated palynofacies and organic geochemical approach abstract a study on source rock characterization and paleoenvironmental interpretation has been carried out on a relatively thick miocene sedimentary succession from three wells gh 404 2a gh 420 1 sa e6a in the southern gulf of suez egypt the compilation of detailed optical investigations including palynofacies analysis spore coloration index sci vitrinite reflectance vrr and source rock geochemical data enables a detailed evaluation of organic matter om richness kerogen type and thermal maturation level despite their high content of calcium carbonate up to 52 the studied sediments yielded sufficient palynologic residue for a detailed palynofacies and organic petrographic study the palynomorph content comprises mainly marine components essentially dinoflagellate cysts and accessorily microforaminiferal linings while terrestrial derived material is relatively rare persistent occurrence of amorphous organic matter aom indicates that dysoxic to anoxic conditions prevailed throughout the deposition of the investigated sediments the main objective of this study is to combine organic geochemical and palynological data in an attempt to assess the source rock potential of the rudeis and kareem formations in the gulf of suez these data in addition also allow for the reconstruction of the depositional environment the present investigation employs multimode microscopic methods using transmitted white light along with incident light fluorescence microscopy for the first time geochemical and petrographic analyses performed on bulk rock samples and palynological residues demonstrate that both the rudeis formation and the kareem formation are mainly of kerogen type iii or mixed type ii iii independent thermal maturation specific parameters such as rock eval tmax vrr and sci indicate an immature to early mature stage palynofacies analyses combined with organic geochemical data indicate that the rudeis formation was deposited under shallow to open marine conditions whereas the overlying kareem formation was formed mainly in an open marine setting

strong influence of water vapor source dynamics on stable isotopes in precipitation observed in southern meghalaya ne india to calibrate 18o time series from speleothems in the eastern indian summer monsoon ism region of india and to understand the moisture regime over the northern bay of bengal bob we analyze the 18o and d of rainwater collected in 2007 and 2008 near cherrapunji india d values range from 18 5 to 144 4 while 18o varies between 0 8 and 18 8 the local meteoric water line lmwl is found to be indistinguishable from the global meteoric water line gmwl late ism september october rainfall exhibits lowest 18o and d values with little relationship to the local precipitation amount there is a trend to lighter isotope values over the course of the ism but it does not correlate with the patterns of temperature and rainfall amount 18o and d time series have to be interpreted with caution in terms of the amount effect in this subtropical region we find that the temporal trend in 18o reflects increasing transport distance during the ism isotopic changes in the northern bob surface waters during late ism and vapor re equilibration with rain droplets using an isotope box model for surface ocean waters we quantify the potential influence of river runoff on the isotopic composition of the seasonal freshwater plume in the northern bob temporal variations in this source can contribute up to 25 of the observed changes in stable isotopes of precipitation in ne india to delineate other moisture sources we use backward trajectory computations and find a strong correlation between source region and isotopic composition palaeoclimatic stable isotope time series from northeast indian speleothems likely reflect changes in moisture source and transport pathway as well as the isotopic composition of the bob surface water all of which in turn reflect ism strength stalagmite records from the region can therefore be interpreted as integrated measures of the ism strength

lower miocene nukhul formation gebel el zeit egypt model for structural control on early synrift strata and reservoirs gulf of suez the aquitanian early burdigalian lower miocene nukhul formation at gebel el zeit egypt was deposited during early stages of gulf of suez rifting the unit dips 8 15 less than underlying prerift strata indicating that significant rotation and extension preceded subsidence of the gebel el zeit fault block the nukhul formation at gebel el zeit is up to 75 m thick in outcrop and consists of a lower sandstone and an upper carbonate unit the formation varies considerably along strike because of syndepositional differential movement of small fault bounded blocks the lower clastic unit at south gebel el zeit contains poorly sorted conglomeratic marly sandstone that commonly displays grading and bouma sequences beds were deposited below storm base by sediment gravity flows thicker intervals are inferred to fill small structurally controlled submarine gullies that funneled sand and gravel southwestward to a half graben basin in contrast an inferred correlative thin basal conglomeratic unit in north gebel el zeit was deposited in a shallow marine setting the presence of basement clasts in nukhul strata indicates early syndepositional uplift due to structural tilting the upper carbonate unit consists of bioclast peloid and intraclast packstone wackestone and grainstone with minor floatstone rudstone and coral algal boundstone carbonate strata were deposited variously in deep marine low energy peritidal and subtidal and reefal environments deeper submerged blocks were the site of carbonate resedimentation or deeper shelf deposition reefs and shallow marine bioclast shoals formed on higher submerged blocks nukhul strata show that synrift reservoir prediction in the gulf of suez the red sea and presumably in other rifts requires mapping of synrift cross faults and fault block by fault block facies analysis robert winn is a consulting geologist he received a ph d from the university of wisconsin madison in 1975 and joined marathon oil company as a research geologist in 1977 he left marathon in 1994 for the university of papua new guinea where he was senior lecturer and then associate professor he was head of the geology department from 1996 to 2000 his primary interests are in clastic sedimentology and sequence stratigraphy paul crevello is a consulting geologist and technical director of petrexasia which he formed in 1997 he received an m s degree from the university of miami 1978 and a ph d from colorado school of mines 1989 he was employed by marathon oil as a research geologist from 1978 to 1994 and by the university of brunei as senior lecturer from 1994 to 1997 his specialties are in sequence stratigraphy and sedimentology of carbonate and turbidite systems and the integrated calibration of 3 d reservoir models william bosworth is employed by marathon oil company he joined marathon in 1984 and has worked principally on international exploration and development projects from 1980 to 1984 he taught structural geology and tectonics at colgate university in hamilton new york his research interests are principally in extensional tectonics continental stress field evolution and the paleogeodynamics of the african plate

geochemical fingerprints of climate variation and the extreme la nina 2010 11 as recorded in a tridacna squamosa shell from sulawesi indonesia abstract we used a tridacna squamosa tridacnidae bivalvia shell that lived between 2006 and 2012 to reconstruct environmental conditions in south east sulawesi indonesia we focused mainly on estimating the influence of temperature and rainfall on the shell geochemistry as well as enso anomalies comparison of the measured and theoretical 18 o values show clear seasonal variations and confirms that this species secretes its shell at isotopic equilibrium the 18 o in t squamosa shows how the increased rainfall associated with monsoon precipitations in this area influences the 18 o shell signal during the rainy season the correlation between shell 18 o and sst r 2 0 62 decrease in warm wet seasons sst 28 5 c shell mg ca profiles presents better correlation with sst r 2 0 8 than sr ca profiles r 2 0 52 shell ba ca ratio increases during each dry season when primary productivity is maximum secondary ba ca peaks also occur during the certain wet seasons and appear associated with abnormal enhanced runoff shell 13 c co varies with primary productivity and salinity with highest 13 c values occurring during the dry seasons during 2010 11 abnormal values were detected in all geochemical proxies as result of the strong la nina event this calibration study demonstrates the ability of t squamosa shells to accurately reflect present day environmental processes with seasonal resolutions and to define the local signature of hydrological changes associated with enso

guidelines for evaluating petroleum source rock using programmed pyrolysis rock eval pyrolysis is used to rapidly evaluate the petroleum generative potential and thermal maturity of rocks accurate conclusions require programs every 30 60 ft 9 18 m understanding of interpretive pitfalls and supporting data such as visual kerogen vitrinite reflectance and elemental analyses the generative potential of coals is commonly overestimated by pyrolysis and is best determined by elemental analysis and organic petrography most coals show high s2 s3 5 and low hi values 300 mg hc g toc migrated oil and mud additives which alter rock eval data can sometimes be removed by special processing for immature rocks bimodal s2 peaks and pi values over 0 2 indicate contamination pyrolysis downgrades organic poor clay rich rocks which show lower hi and higher tmax values than isolated kerogen because of adsorption of pyrolyzate on the clays tmax values for small s2 peaks 0 2 mg hc g toc are unreliable tmax is affected by maturation organic matter type contamination and the mineral matrix s3 is sensitive to inorganic and adsorbed carbon dioxide and to instrumentation problems acidification of carbonate rich samples and proper maintenance improves s3 measurement constant sample weights 100 mg are recommended below a threshold weight tmax increases by up to 10 c and other parameters decrease organic rich samples which overload the detector can be diluted with carbonate detector linearity is determined by pyrolyzing various weights of an organic rich rock

new speleothem data from molinos and ejulve caves reveal holocene hydrological variability in northeast iberia new speleothem records from northeastern iberian caves provide data to explore the climatic patterns during the holocene we present 13c and mg ca from three speleothems from two different caves located in the iberian range allowing replication of the climatic signal for several millennia through the integration of those stalagmites covering since the holocene onset to 2 ka the early holocene 11 7 8 5 ka appears as the wettest interval a marked change towards aridity is observed during the middle holocene 8 5 4 8 ka and an increase of humidity afterwards 4 8 2 ka this three part pattern contrasting with other iberian sequences seems to be associated with the different role that seasonality has played in the response of different proxies or records to changes in water availability interpreting our speleothem records as changes in winter spring precipitation along the holocene allows reconciling previous data on hydrological variability from the western mediterranean borderlands

oil bitumen and other confusing concepts what do lab experiments really tell us using the terms bitumen and oil carelessly and failing to properly separate chemical reactions from mass transport processes can lead to models that fail when applied to natural processes data from both laboratory experiments and source rock measurements are used to develop a self consistent picture of generation of c15 extractable organic matter eom lighter hydrocarbons hc and the fractionation that occurs during expulsion from the rock in either laboratory experiments or nature despite statements in the literature hydrocarbons are generated immediately from kerogen in parallel with heavy compounds containing nitrogen sulfur and oxygen nsos and probably with similar rate constants from kerogen and nsos under all conditions because the same bonds are being broken to form them peak concentrations of c15 eom in the rock occur prior to peak generation of unexpelled hc because of weaker bonds being broken not because of a sequential chemical reaction mechanism this earlier generation of c15 eom relative to hc is similar for semiopen experiments hydrous pyrolysis and in nature as is the fractionation of chemical types during expulsion properly derived activation energies for expelled oil formation from open semiopen and hydrous pyrolysis are similar once transport contributions are considered

the record of cosmogenic radiogenic fissiogenic and trapped noble gases in recently recovered chinese and other chondrites abstract we performed a comprehensive study of the noble gas isotopic abundances in thirty six chondrites including twenty seven chondrites recovered in china the large data base allows us to recognize some new characteristics of the nuclear record in chondritic matter the comparison of the trapped noble gas release pattern for ordinary and carbonaceous chondrites shows that the planetary trapped noble gases in ordinary chondrites are released mainly above 1200 c whereas 85 of these gases in carbonaceous chondrites are degassed at 200 c there exists a clear correlation of the fraction of trapped xe released at 1200 c and petrologic type of chondrites it thus appears that the carrier phases of the trapped noble gases in ordinary and in carbonaceous chondrites may not be the same the ngawi ll3 chondrite is solar gas rich the solar gases in meteorites and lunar surface material are mixtures of solar wind sw and solar energetic particles sep we show that the variations of the 3 he 4 he and 20 ne 22 ne ratios for solar gas rich meteorites and lunar surface material could be either due to preferential diffusive losses of the lighter isotopes of he and ne or due to a change of the sw sep flux ratio with time furthermore we demonstrate that the 81kr concentration is a function of the shielding depth of a sample within the meteoroid deviations from this depth dependency curve are observed for jilin h5 lishui l5 suizhou l6 and dongtai ll6 a complex exposure history for jilin is thus confirmed and is possible for the other three chondrites cosmic ray exposure ages are calculated based on six different nuclides 3he 21ne 38ar 83kr 126xe and 81kr kr in most cases good agreement is observed for the ages derived from the different methods quality classes are assigned to the exposure ages and the age distributions are discussed in some meteorites we observe effects induced by secondary cosmicray produced neutrons epithermal neutron fluxes jn 30 300 ev and fast neutron fluxes jn 5 mev are derived based on the reactions 79br n 80kr and 24mg n 21ne respectively and preatmospheric masses of the meteoroids are estimated we show that the ratio j n 30 300 ev j n 5 mev increases with increasing preatmospheric mass we introduce a 3he exposure age 21ne exposure age vs 4he gas retention age 40ar gas retention age diagram that is a powerful tool for distinguishing different thermal histories of meteoroids finally in some chondrites we observe xe produced by 244pu fission and calculate the time span between fission xe retention in these chondrites and that of the angra dos reis achondrite we find that the ordinary chondrites started to retain fission xe 48 30 ma earlier than angra dos reis we do not observe systematic differences between h l and ll or type 5 and 6 chondrites with respect to the time of fission xe retention

a stalagmite record of changes in atmospheric circulation and soil processes in the brazilian subtropics during the late pleistocene we present a high resolution 116 000 year carbon stable isotope record from a stalagmite from southern brazil which has been precisely dated using the u series method evaluation of carbon and oxygen isotope ratios together with the speleothem growth history suggest that the carbon isotopic composition of the speleothem is primarily controlled by biogenic co2 supply from the soil which is in turn affected by temperature and secondarily rainfall amount thus the speleothem provides evidence of paleoenvironmental change in southern brazil during the last glacial period predominantly high d 13 c values and low stalagmite growth rates reflect persistent cool conditions during most of the glacial period in subtropical brazil this cooling is probably related to an intensified extratropical circulation with more frequent and intense cold surges reaching a maximum at approximately 19 ky b p this cooling tendency is interrupted during periods of high obliquity values within the full glacial period at 93 85 and 47 40 ky b p and after 19 ky b p when a dramatic decrease in d 13 c marks the deglaciation time in the continent unlike d 18 o the d 13 c record does not exhibit a strong response to precessional forcing instead it shows a strong 40 ky obliquity signal here we propose that local temperature and thus the biological processes in the soil are primarily steered by the gradients of temperature between low and mid high latitudes which influence the meridional heat transport these gradient changes in turn are paced by obliquity r 2006 published by elsevier ltd

the composition and history of breccia 67015 from north ray crater we have examined feldspathic fragmental breccia 67015 from the rim of north ray crater and found it to be the most diverse and complex of the apollo 16 ffbs it contains a wider range of clast types than any of the others and is not dominated by any single lithology we have identified several crystalline lithologies occurring in minor amounts that we believe represent highland plutonic rocks plagioclase fragments are the most abundant breccia constituent followed by clasts of impact melt rocks and granulites the impact melts are of two main types feldspathic fragment laden melts and mafic kreepy melt rocks of vha basalt composition textural evidence indicates that some of the vha melts were hot and plastic when they accumulated into the breccia 40ar 39ar dates show that both types of melts solidified about 3 9 109 years ago magnetic measurements on clasts show a scatter of nmr directions making it impossible to read a consistent imprint of an ancient dipolar magnetic field previous studies of apollo 16 stratigraphy suggested that kreepy melt rocks were introduced to the site as imbrium impact ejecta about 3 8 106 years ago our results indicate that the highlands crust contained kreep components as early as 3 9 109 years ago

atlantic forcing of western mediterranean winter rain minima during the last 12 000 years abstract the limited availability of high resolution continuous archives insufficient chronological control and complex hydro climatic forcing mechanisms lead to many uncertainties in palaeo hydrological reconstructions for the western mediterranean in this study we present a newly recovered 19 63 m long core from lake sidi ali in the north african middle atlas a transition zone of atlantic western mediterranean and saharan air mass trajectories with a multi proxy approach based on magnetic susceptibility carbonate and total organic c content core scanning and quantitative xrf stable isotopes of ostracod shells charcoal counts cedrus pollen abundance and a first set of diatom data we reconstruct western mediterranean hydro climatic variability seasonality and forcing mechanisms during the last 12 000 yr a robust chronological model based on ams 14 c dated pollen concentrates supports our high resolution multi proxy study long term trends reveal low lake levels at the end of the younger dryas during the mid holocene interval 6 6 to 5 4 cal ka bp and during the last 3000 years in contrast lake levels are mostly high during the early and mid holocene the record also shows sub millennial to centennial scale decreases in western mediterranean winter rain at 11 4 10 3 9 2 8 2 7 2 6 6 6 0 5 4 5 0 4 4 3 5 2 9 2 2 1 9 1 7 1 5 1 0 0 7 and 0 2 cal ka bp early holocene winter rain minima are in phase with cooling events and millennial scale meltwater discharges in the sub polar north atlantic our proxy parameters do not show so far a clear impact of saharan air masses on mediterranean hydro climate in north africa however a significant hydro climatic shift at the end of the african humid period 5 ka indicates a change in climate forcing mechanisms the late holocene climate variability in the middle atlas features a multi centennial scale nao type pattern with atlantic cooling and western mediterranean winter rain maxima generally associated with solar minima

north iberian temperature and rainfall seasonality over the younger dryas and holocene abstract several stalagmite records have yielded important but discontinuous insights into northern iberian climate since the last glacial here we present the first continuous iberian stalagmite based reconstruction of climate since the bolling allerod interstadial from a single stalagmite sample gar 01 from la garma cave cantabria the 13 5 ka gar 01 record provides the opportunity for replication continuation and aggregation of previously published records from northern spain the gar 01 record reveals shifts in oxygen isotope ratios that are inexplicable by appealing to a single control i e exclusively temperature rainfall amount etc herein we explore the potential role of rainfall and temperature seasonality shifts on the new 18o record using a simple monte carlo approach to estimate the seasonal distribution of rainfall and the annual temperature range at 100 year timeslices across the record this model is corroborated by intervals of monthly resolved laser ablation trace element data providing glimpses into past iberian seasonality shifts the most salient features of the modelled results include extremely dry younger dryas winters 12 9 11 6 ka bp and several intervals during the mid holocene with almost no summer rainfall e g at 4 2 and 9 0 ka bp by 1 6 ka bp a near modern rainfall seasonality was established according to the modelling results seasonal rainfall and temperature distribution variability can account for 95 of the record the model presented here provides a new tool for extracting critical missing seasonality information from stalagmite 18o records intervals where the model does not converge may represent transient climate anomalies with unusual origins that warrant further investigation

water isotopic variability in mallorca a path to understanding past changes in hydroclimate this paper reports the first results on 18o and 2h analysis of precipitations cave drip waters and groundwaters from sites in mallorca balearic islands western mediterranean a key region for paleoclimate studies understanding the isotopic variability and the sources of moisture in modern climate systems is required to develop speleothem isotope based climate reconstructions the stable isotopic composition of precipitation was analyzed in samples collected between march 2012 and march 2013 the values are in the range reported by gnip palma station based on these results the local meteoric water line 2h 7 9 0 3 18o 10 8 2 5 was derived with slightly lower slope than gmwl the results help tracking two main sources of air masses affecting the study sites rain events with the highest 18o values 5 originate over the mediterranean sea whereas the more depleted samples 50 m limestone cap arta exhibit more negative values a well homogenized aquifer supplied by rainwaters of both origins is clearly indicated by groundwater 18o values which show to be within 2 4 of the unweighted arithmetic mean of 7 4 although limited the isotopic data presented here constitute the baseline for future studies using speleothem 18o records for western mediterranean paleoclimate reconstructions

critical considerations when assessing hydrocarbon plays using rock eval pyrolysis and organic petrology data data quality revisited abstract the dramatic increase in exploration for unconventional hydrocarbon resources has inherently fuelled the need for new source rock geochemical data the need for new data comes along with an increasing number of new users many of whom do not possess the background to interpret accurately and evaluate the quality of data sets generated by different geochemical screening techniques e g rock eval pyrolysis vitrinite reflectance here datasets from rock eval pyrolysis vitrinite reflectance and leco toc analyses are scrutinized and compared to show how failing to recognize good vs bad datasets can dramatically change interpretations during prospect or play appraisals detector saturation contamination of the sample with drilling fluid and suppression of both tmax and vitrinite reflectance are examples of complications that could compromise the validity of the results and the play or prospect reviews derived from them in addition misconceptions such as leco toc is better than rock eval 6 toc expressed by many users are a consequence of the lack of understanding of how different screening techniques and instrumentation work a solid understanding of these pitfalls and limitations can provide inexperienced geoscientists and engineers with the required support to improve risk maps for hydrocarbon charge analysis and source rock evaluations when using classic guidelines for interpreting results

speleothem calcite farmed in situ modern calibration of δ18o and δ13c paleoclimate proxies in a continuously monitored natural cave system abstract understanding the relationships between speleothem stable isotopes 13 c 18 o and in situ cave forcing mechanisms is important to interpreting ancient stalagmite paleoclimate records cave studies have demonstrated that the 18 o of inorganically precipitated low temperature speleothem calcite is systematically heavier than the 18 o of laboratory grown calcite for a given temperature to understand this apparent offset rainwater cave drip water groundwater and modern naturally precipitated calcite farmed in situ were grown at multiple locations inside hollow ridge cave in marianna florida high resolution micrometeorological air chemistry time series and ventilation regimes were also monitored continuously at two locations inside the cave supplemented with periodic bi monthly air gas grab sample transects throughout the cave cave air chemistry and isotope monitoring reveal density driven airflow pathways through hollow ridge cave at velocities of up to 1 2 m s 1 in winter and 0 4 m s 1 in summer hollow ridge cave displays a strong ventilation gradient in the front of the cave near the entrances resulting in cave air that is a mixture of soil gas and atmospheric co 2 a clear relationship is found between calcite 13 c and cave air ventilation rates estimated by proxies pco 2 and 222 rn calcite 13 c decreased linearly with distance from the front entrance to the interior of the cave during all seasons with a maximum entrance to interior gradient of 13 c caco3 7 a whole cave hendy test at multiple contemporaneous farming sites reveals that ventilation induces a 1 9 0 96 13 c offset between calcite precipitated in a ventilation flow path and calcite precipitated on the edge or out of flow paths this interpretation of the hendy test has implications for interpreting 13 c records in ancient speleothems calcite 13 c caco3 may be a proxy not only for atmospheric co 2 or overlying vegetation shifts but also for changes in cave ventilation due to dissolution fissures and ceiling collapse creating and plugging ventilation windows farmed calcite 18 o was found to exhibit a 0 82 0 24 offset from values predicted by both theoretical calculations and laboratory grown inorganic calcite unlike 13 c caco3 oxygen isotopes showed no ventilation effects i e 18 o caco3 appears to be a function of growth temperature only although we cannot rule out a small effect of unmeasured gradients in relative humidity evaporation accompanying ventilation our results support the findings of other cave investigators that water calcite fractionation factors observed in speleothem calcite are higher that those measured in laboratory experiments cave and laboratory calcite precipitates may differ mainly in the complex effects of kinetic isotope fractionation combining our data with other recent speleothem studies we find a new empirical relationship for cave specific water calcite oxygen isotope fractionation across a range of temperatures and cave environments 1000 ln 16 1 10 3 t 1 24 6 with a fractionation temperature dependence of 18 o t 0 177 c lower than the currently accepted 0 206 c

petroleum geology and potential hydrocarbon plays in the gulf of suez rift basin egypt the gulf of suez in egypt has a north northwest south southeast orientation and is located at the junction of the african and arabian plates where it separates the northeast african continent from the sinai peninsula it has excellent hydrocarbon potential with the prospective sedimentary basin area measuring approximately 19 000 km 2 and it is considered as the most prolific oil province rift basin in africa and the middle east this basin contains more than 80 oil fields with reserves ranging from 1350 to less than 1 million bbl in reservoirs of precambrian to quaternary age the lithostratigraphic units in the gulf of suez can be subdivided into three megasequences a prerift succession pre miocene or paleozoic eocene a synrift succession oligocene miocene and a postrift succession post miocene or pliocene holocene these units vary in lithology thickness areal distribution depositional environment and hydrocarbon importance geological and geophysical data show that the northern and central gulf of suez consist of several narrow elongated depositional troughs whereas the southern part is dominated by a tilt block terrane containing numerous offset linear highs major prerift and synrift source rocks have potential to yield oil and or gas and are mature enough in the deep kitchens to generate hydrocarbons geochemical parameters sterane distribution and biomarker correlations are consistent with oils generated from marine source rocks oils in the gulf of suez were sourced from potential source rock intervals in the prerift succession that are typically oil prone type i and in places oil and gas prone type ii or are composites of more than one type multiple types i ii or iii for oil prone oil and gas prone or gas prone respectively the reservoirs can be classified into prerift reservoirs such as the precambrian granitic rocks paleozoic cretaceous nubian sandstones upper cretaceous nezzazat sandstones and the fractured eocene thebes limestone and synrift reservoirs such the miocene sandstones and carbonates of the nukhul rudeis kareem and belayim formations and the sandstones of south gharib zeit and

limitations of use of organic petrographic techniques for identification of petroleum source rocks organic petrographic and organic geochemical studies have been conducted on 58 sediment samples of differing ages and depositional environments in this study interpretations of petroleum source rock potential based on data from transmitted light microscopy show a poor correlation with those derived from chemical data this lack of correlation arises from the failure to distinguish consistently between hydrogen poor and hydrogen rich amorphous organic matter and inability to detect hydrogen rich components exinite and resinite in coal fragments interpretations based on data from reflected light microscopy show a better correlation with those derived from chemical studies but difficulties still remain these difficulties arise from inability except on the basis of luorescence intensity to distinguish hydrogen rich from hydrogen poor organic matter in a finely dispersed state

triple isotope δd δ17o δ18o study on precipitation drip water and speleothem fluid inclusions for a western central european cave nw switzerland abstract deuterium d and oxygen 18o isotopes are powerful tracers of the hydrological cycle and have been extensively used for paleoclimate reconstructions as they can provide information on past precipitation temperature and atmospheric circulation more recently the use of 17oexcess derived from precise measurement of 17o and 18o gives new and additional insights in tracing the hydrological cycle whereas uncertainties surround this proxy however 17oexcess could provide additional information on the atmospheric conditions at the moisture source as well as about fractionations associated with transport and site processes in this paper we trace water stable isotopes d 17o and 18o along their path from precipitation to cave drip water and finally to speleothem fluid inclusions for milandre cave in northwestern switzerland a two year long daily resolved precipitation isotope record close to the cave site is compared to collected cave drip water 3 months average resolution and fluid inclusions of modern and holocene stalagmites amount weighted mean d 18o and 17o are 71 0 9 9 5 2 for precipitation 60 3 8 7 4 6 for cave drip water and 61 3 8 3 4 7 for recent fluid inclusions respectively second order parameters have also been derived in precipitation and drip water and present similar values with 18 per meg for 17oexcess whereas d excess is 1 5 more negative in drip water furthermore the atmospheric signal is shifted towards enriched values in the drip water and fluid inclusions of 10 for d the isotopic composition of cave drip water exhibits a weak seasonal signal which is shifted by around 8 10 months groundwater residence time when compared to the precipitation moreover we carried out the first 17o measurement in speleothem fluid inclusions as well as the first comparison of the 17o behaviour from the meteoric water to the fluid inclusions entrapment in speleothems this study on precipitation drip water and fluid inclusions will be used as a speleothem proxy calibration for milandre cave in order to reconstruct paleotemperatures and moisture source variations for western central europe

internal structure and deformation of an accommodation zone in the northern part of the suez rift abstract detailed structural study of the eastern onshore part of the gharandal accommodation zone that separates the northern sw dipping and central ne dipping half grabens of the suez rift helped decipher the internal structure and deformation of accommodation zones of continental rifts this 60 km wide zone is affected by pure normal faulting the ne dipping faults of the northern half graben extend southward into the accommodation zone where they interfinger with sw dipping faults extending from the central half graben these two sets of rift parallel faults form several horsts and grabens in the accommodation zone areas dipping parallel to the northern or southern half grabens form several intermixing dip domains in the accommodation zone smaller scale accommodation of dip between these dip domains proceeds by the development of rift parallel folds twist zones in contrast to the southern accommodation zone of the suez rift the internal structure of the gharandal accommodation zone is believed to be representative of accommodation zones in regions a unaffected by prerift structures lying at high angles to the rift and b experiencing relatively small extension accommodation zones in areas having pre rift structures lying at high angle to the rift have relatively narrow width and are characterized by transverse strike slip faults strike slip movement on these faults is related to the torsional strain resulting from the opposite tilt directions and transport of fault blocks of adjacent half grabens

single stage exposure history of lunar highland breccias 60018 67435 and 67455 lunar breccias 60018 67435 and 67455 experienced a single stage exposure to cosmic rays these materials had been shielded from cosmic rays when 60018 was excavated by the south ray cratering event about 2 m y ago and rocks 67435 and 67455 by the north ray impact about 50 m y ago after excavation the shielding depth of the investigated samples was less than 40 g cm2 in accord with the location at the time of collection the gas retention ages as calculated from 136xe produced by the spontaneous fission of 238u and 244pu show that the breccia minerals solidified and cooled 3 6 4 1 b y ago the breccias contain measurable amounts of trapped noble gases which however are two to four orders of magnitude lower than in typical lunar soil

reconstruction of temperature in the central alps during the past 2000 yr from a δ18o stalagmite record the precisely dated isotopic composition of a stalagmite from spannagel cave in the central alps is translated into a highly resolved record of temperature at high elevation during the past 2000 yr temperature maxima during the medieval warm period between 800 and 1300 ad are in average about 1 7 8c higher than the minima in the little ice age and similar to present day values the high correlation of this record to d 14 c suggests that solar variability was a major driver of climate in central europe during the past 2 millennia d 2005 elsevier b v all rights reserved

re examination of the formation ages of the apollo 16 regolith breccias abstract the lunar regolith is exposed to irradiation from the solar wind and to bombardment by asteroids comets and inter planetary dust fragments of projectiles in the lunar regolith can potentially provide a direct measure of the sources of exogenous material being delivered to the moon constraining the temporal flux of their delivery helps to address key questions about the bombardment history of the inner solar system here we use a revised antiquity calibration after eugster et al 2001 that utilises the ratio of trapped 40 ar 36 ar parentless 40 ar derived from radioactive decay of 40 k against solar wind derived 36 ar to semi quantitatively calculate the timing of the assembly of the apollo 16 regolith breccias we use the trapped 40 ar 36 ar ratios reported by mckay et al 1986 our model indicates that the apollo 16 ancient regolith breccia population was formed between 3 8 and 3 4 ga consistent with regoliths developed and assembled after the imbrium basin forming event at 3 85 ga and during a time of declining basin forming impacts the material contained within the ancient samples potentially provides evidence of impactors delivered to the moon in the late imbrian epoch we also find that a young regolith population was assembled probably by local impacts in the apollo 16 area in the eratosthenian period between 2 5 and 2 2 ga providing insights to the sources of post basin bombardment the soil like regolith breccia population and the majority of local apollo 16 soils were likely closed in the last 2 ga and therefore potentially provide an archive of projectile types in the eratosthenian and copernican periods

a δ13c and δ2h leaf wax record from the late quaternary loess paleosoil sequence el paraiso central spain abstract the mediterranean peninsula increasingly suffers from droughts and aridity the first consequences of global climate change in that region precise scenarios for the region s future climate predictions require knowledge about the processes of past climate changes but information about the western mediterranean climate and its history is controversial for this study we applied compound specific 13c and 2h analyses on long chain n alkanes in the 8 m el paraiso loess paleosoil sequence lps central spain to investigate climate and environmental changes during the late quaternary the 13c values are most enriched during marine isotope stage mis 3 indicating more arid conditions while lower values during mis 4 and 2 are interpreted to document more humid conditions low values are also recorded for the holocene colluvium which can at least partly be explained with higher concentrations in atmospheric co2 the 2h values are mostly enriched during the last glacial compared to the holocene we suggest that this is mainly controlled by isotopic effects related to the moisture source yet other possible effects like evapotranspirative enrichment and changes in atmospheric circulation patterns shouldn t be ruled out our results corroborate previous findings based on leaf wax patterns geomorphological records and climate models they all indicate relatively humid conditions during mis 2 compared to more arid phases during mis 3

petroleum generation kinetics single versus multiple heating ramp open system pyrolysis some recent publications promote one run open system pyrolysis experiments using a single heating rate ramp and fixed frequency factor to determine the petroleum generation kinetics of source rock samples because compared to multiple ramp experiments the method is faster less expensive and presumably yields similar results some one ramp pyrolysis experiments yield kinetic results similar to those from multiple ramp experiments however our data for 52 worldwide source rocks containing types i ii iis ii iii and iii kerogen illustrate that one ramp kinetics introduce the potential for significant error that can be avoided by using high quality kinetic measurements and multiple ramp experiments in which the frequency factor is optimized by the kinetic software rather than fixed at some universal value the data show that kinetic modeling based on a discrete activation energy distribution and three different pyrolysis temperature ramps closely approximates that determined from additional runs provided the three ramps span an appropriate range of heating rates for some source rocks containing well preserved kerogen and having narrow activation energy distributions both single and multiple ramp discrete models are insufficient and nucleation growth models are necessary instrument design thermocouple size or orientation and sample weight likely influence the acceptable upper limit of pyrolysis heating rate caution is needed for ramps of 30 50 c min which can cause temperature errors due to impaired heat transfer between the oven sample and thermocouple compound volatility may inhibit pyrolyzate yield at the lowest heating rates depending on the effectiveness of the gas sweep we recommend at least three pyrolysis ramps that span at least a 20 fold variation of comparatively lower rates such as 1 5 and 25 c min the product of heating rate and sample size should not exceed 100 mg c min our results do not address the more fundamental questions of whether kinetic models based on multiple ramp open system pyrolysis are mechanistically appropriate for use in basin simulators or whether petroleum migration through the kerogen network rather than cracking of organic matter represents the rate limiting step in expulsion

source rock evaluation of the cenomanian raha formation bakr oil field gulf of suez egypt observations from palynofacies rgb based sporomorph microscopy and organic geochemistry abstract the gulf of suez area in eastern egypt is one of the most prospective and promising hydrocarbon provinces all over the world sixty drill cuttings samples of the upper cretaceous raha formation 70 120 m have earlier been processed for their palynomorph and palynofacies contents including 36 geochemically screened samples for their source rock potential using toc rock eval 6 turbo the new rock eval 7s instrument along with one of its latest modules the cleansim method the combination between visual palynofacies and rgb based sporomorph color image analysis along with the geochemical results are presented as part of a detailed assessment of the organic matter om types om richness and thermal maturity levels palynofacies analysis defined three associations of om types the first and third associations consist of kerogen type ii the former is dominated by a moderate abundance of amorphous organic matter aom and phytoclasts whilst the latter is dominated by high aom content conversely the second association is dominated by terrigenous fragments of gas prone type iii kerogen the application of rgb analysis indicated a thermally immature to mature stage for some intervals in one of the three studied wells the b 109 geochemical screening results led to divide the raha formation into three distinctive groups which are characterized by varied om qualities and quantities hydrocarbon potential and thermal maturity levels varied thermal maturity levels was related directly to the late cretaceous tectonics like the effect of syrian arc system and the oligocene miocene syn rift activity that led to the opening of the gulf of suez differences in kerogen types were observed between geochemical and palynofacies analyses microscopic investigations of palynofacies dominated aom suggested that most aom particles were of terrigenous origin due to the effect of biodegradation and gradual transformation of phytoclasts into aom reflecting a kerogen type iii instead of kerogen type ii that was indicated by palynofacies analysis ternary plots

a 53 year seasonally resolved oxygen and carbon isotope record from a modern gibraltar speleothem reconstructed drip water and relationship to local precipitation abstract the response of a climate proxy against measured temperature rainfall and atmospheric circulation patterns at sub annual resolution is the ultimate test of proxy fidelity but very few data exist showing the level of correspondence between speleothem climate proxies and the instrumental climate record cave sites on the gibraltar peninsula provide a unique opportunity to calibrate speleothem climate proxies with the longest known available precipitation isotopes and instrumental records an actively growing speleothem sampled from new st michaels cave in 2004 is composed of paired laminae consisting of light columnar calcite and a darker microsparitic calcite stable isotope analysis of samples micromilled in 100 m steps at the equivalent of bi monthly intervals reveals fabric correlated annual cycles in carbon isotopes oxygen isotopes and trace elements responding to seasonal changes in cave microclimate hydrology and ventilation patterns calcite 13 c values reach a minimum in the light columnar fabric and evidence from trace element behaviour and cave monitoring indicates that this grows under cave winter conditions of highest p co 2 whereas the dark microsparitic calcite characterised by elevated 13 c and 18 o values grows under low summer p co 2 conditions drip water 13 c dic reaches a minimum in march april at which time the attenuated 18 o signal becomes most representative of winter precipitation an age model based on cycle counting and the position of the 14 c bomb carbon spike yields a precisely dated winter oxygen isotope proxy of cave seepage water for comparison with the gnip and instrumental climate record for gibraltar the 18 o characteristics of calcite deposited from drip water representing winter precipitation for each year can be derived from the seasonally resolved record and allows reconstruction of the 18 o drip water representing winter precipitation for each year from 1951 2004 these data show an encouraging level of correspondence r 2 0 47 with the 18 o of rainfall falling each year between october and march and on a decadal scale the 18 o of reconstructed winter drip water mirrors secular change in mean winter temperatures

climatic and environmental controls on speleothem oxygen isotope values variations in speleothem oxygen isotope values d 18 o result from a complicated interplay of environmental controls and processes in the ocean atmosphere soil zone epikarst and cave system as such the controls on speleothem d 18 o values are extremely complex an understanding of the processes that control equilibrium and kinetic fractionation of oxygen isotopes in water and carbonate species is essential for the proper interpretation of speleothem d 18 o as paleoclimate and paleoenvironmental proxies and is best complemented by study of site specific cave processes such as infiltration flow routing drip seasonality and saturation state and cave microclimate among others this review is a process based summary of the multiple controls on d 18 o in the atmosphere soil epikarst and speleothem calcite illustrated with case studies primary controls of d 18 o in the atmosphere include temperature and relative humidity through their role in the multiple isotope effects variability and modifications of water d 18 o values in the soil and epikarst zones are dominated by evaporation mixing and infiltration of source waters the isotopically effective recharge into a cave system consists of those waters that participate in precipitation of caco3 resulting in calcite deposition rates which may be biased to time periods with optimal dripwater saturation state recent modeling experimental and observational data yield insight into the significance of kinetic fractionation between dissolved carbonate phases and solid caco3 and have implications for the hendy test to assist interpretation of speleothem d 18 o time series quantitative and semi quantitative d 18 o climate calibrations are discussed with an emphasis on some of the difficulties inherent in using modern spatial and temporal isotope gradients to interpret speleothems as paleoclimate proxy records finally several case studies of globally significant speleothem paleoclimate records are discussed that show the utility of d 18 o to reconstruct past climate

climate controls on rainfall isotopes and their effects on cave drip water and speleothem growth the case of molinos cave teruel ne spain the interpretation of stable isotopes in speleothems in terms of past temperature variability or precipitation rates requires a comprehensive understanding of the climatic factors and processes that influence the 18o signal in the way through the atmosphere to the cave where carbonate precipitates acquiring its final isotopic composition this study presents for the first time in the iberia peninsula an integrated analysis of the isotopic composition of rainfall 18op during 2010 2012 years and through a detailed monitoring survey the transference of the primary isotopic signal throughout the soil and epikarst into the molinos cave teruel ne spain both air temperature and amount of precipitation have an important effect on 18op values clearly imprinting a seasonal variability modulated by an amount effect when rainfall events are more frequent or intense air mass history and atmospheric circulation influences are considered through the study of weather types synoptic scale climate patterns and large scale atmospheric circulation indexes north atlantic oscillation and western mediterranean oscillation revealing a dominant source effect on 18op values in this region where tropical north atlantic and western mediterranean are the two moisture source regions a delay of 2 3 months occurs between the dripwater oxygen isotopic composition 18od respect to 18op values as a consequence of large residence time in the epikarst limited calcite precipitates are found from winter to spring when 18od values are less negative and dripwater rates are constant this study suggests that ne iberian 18ocalcite proxy records are best interpreted as reflecting a combination of parameters not just paleotemperature or paleorainfall and if extending present day situation towards the recent past a biased signal towards winter values should be expected in molinos speleothem records

lunar surface processes inferred from cosmogenic radionuclides in apollo 16 double drive core 68002 68001 abstract measurements of cosmogenic 10be 26al and 36cl in apollo 16 double drive core 68002 68001 are combined with a high resolution digital surface model of the sampling site to investigate the surface processes on the moon we find both a significant deficit of solar cosmic ray scr produced 26al and a lack of scr produced 36cl in the top 3 5 g cm2 of the lunar regolith the topographic model shows the core was taken from just inside a crater with a rim diameter of 25 30 cm these observations are consistent with regolith removal and displacement by a shallow impact that occurred on the order of 100 kyr ago or less our findings are also compatible with shallow mixing or gardening of the lunar regolith to depths of a few cm a value often found in other lunar cores over the 106 yr averaging times of 26al and 53mn measurements more definitive regolith mixing depth estimates are not possible due to the likelihood of disturbance in the top of the core as a result of sampling and or handling our results support the hypothesis that the lunar surface experiences more frequent disturbances by small primary and secondary impacts than has previously been assumed additionally we find no evidence that fine grained ejecta from the 2 0 myr old south ray crater impact reached this site if the layer of fine grained ejecta that reached the sampling site from the south ray crater was no more than a few cm thick this absence can be explained by the erosion that formed the small relatively recent crater at the coring location

high resolution isotope records of early holocene rapid climate change from two coeval stalagmites of katerloch cave austria abstract two coeval stalagmites from katerloch cave show pronounced intervals of low 18o values around 8 2 9 1 and 10 0 kyr all ages are reported before the year 2000 ad and represent an inorganic u th dated climate archive from the southeast of the european alps a region where only very few well dated climate records exist the o isotope curves providing near annual resolution allow a direct comparison to the greenland ice core records as temperature was the primary factor controlling the o isotopic composition of katerloch speleothems the 8 2 kyr climate anomaly lasted about one century from 8196 to 8100 yr with a maximum amplitude of 1 1 at 8175 yr the event is characterized by a rapid onset and a more gradual demise and u th data as well as annual lamina counting support a rapid climate change towards cooler conditions within 10 20 yr there is no strong evidence that the 8 2 kyr anomaly was superimposed on a pronounced longer term cooling episode nor do the new data support two separate cooling events within the 8 2 kyr event as reported by other studies our record also shows a distinct climate anomaly around 9 1 kyr which lasted 70 110 yr and showed a maximum amplitude of 1 0 i e it had a similar duration and amplitude as the central 8 2 kyr event compared to the 8 2 kyr event the 9 1 kyr anomaly shows a more symmetrical structure but onset and demise still occurred within a few decades only the different progression of the 8 2 asymmetrical and 9 1 kyr anomaly symmetrical suggests a fundamental difference in the trigger and or the response of the climate system moreover both stalagmites show evidence of a climate anomaly around 10 0 kyr which was of comparable magnitude to the two subsequent events using a well constrained modern calibration between air temperature and 18o of precipitation for the study area and cave monitoring data confirming speleothem deposition in katerloch reflecting cave air temperature a maximum cooling by ca 3 c can be inferred at 8 2 and 9 1 kyr which is similar to other estimates e g from lake ammersee north of the alps the o isotopic composition of meteoric precipitation however is a complex tracer of the hydrological cycle and these temperature estimates do not take into account additional effects such as changes in the source area or synoptic shifts apart from that the relative thickness of the seasonally controlled lamina types in the katerloch stalagmites remains rather constant across the intervals comprising the isotopic anomalies i e the stalagmite petrography argues against major shifts in seasonality during the early holocene climate excursions

modelling the δ18o value of cave drip water and speleothem calcite abstract stable isotope signals recorded in speleothems have provided important insights about past climate variability in recent years quantitative reconstruction of mean annual temperature and the amount of precipitation however remains difficult because the stable isotope signals are influenced by various processes here we present a drip water model which shows how these climate parameters affect the oxygen isotope signal of cave drip water in the model the dependence of the 18 o value of drip water on mean annual temperature is established by correlation to the amount of winter precipitation and winter temperature application of the model to two caves in western germany reveals a strong influence of winter rainfall on the oxygen isotope composition of cave drip water in this region assuming equilibrium isotope fractionation between drip water and calcite we provide a function relating the 18 o value of speleothem calcite to mean annual surface temperature this function shows a clear anticorrelation between temperature and the 18 o value of speleothem calcite which has been previously reported for several caves in central and northern europe by inverse application of this function we tentatively reconstruct average temperatures for the period between 6 and 1 5 ka from the 18 o signals of two stalagmites from atta and bunker cave western germany the resulting temperature curves are very sensitive to the value used for the correlation between the amount of winter precipitation and winter temperature since this correlation was probably not constant in the past the reconstructed temperature curves are associated with substantial uncertainty

orbital to millennial scale climate variability during marine isotope stages 5 to 3 in northeast iberia abstract the climate during the last glacial cycle was characterized by abrupt millennial scale changes superimposed on long term orbital control this study examines this climate variability for northeast iberia for the time interval 118 9 to 36 9 kyr using a multi proxy approach 18o 13c and mg ca applied to a stalagmite that covers this period continuously during marine isotope stage mis 5 and 4 18o is controlled by orbital pacing whereby more humid conditions prevailed during minima in boreal summer precession in contrast during mis 3 18o lags precession and co varies with 13c 0 53 p value

petrology and geochemistry of lunar dimict breccia 61015 dimict breccia 61015 consists dominantly of granulated anorthosite and impact melt rock of vha very high alumina basalt composition the anorthosite is a typical apollo 16 ferroan anorthosite except that it is slightly more augite rich than most other ferroan anorthosites the breccia probably formed in the floor of an expanding crater cavity by the following process impact melt generated within the cavity was injected into underlying anorthositic bedrock and solidified rapidly and the anorthosite and melt rock were then fragmented by deformation in the later stages of the impact all the apollo 16 dimict breccias except perhaps 61016 appear to have formed in the same impact the source crater cannot yet be identified but it may be an intermediate sized 50 150 km diameter crater within a few hundred kilometers of the apollo 16 site in the direction of the imbrium basin of either pre nectarian or post nectarian pre imbrian age the breccia has been affected by at least one and perhaps as many as four recent small impacts the most recent was probably the south ray impact the recent impact s produced internal shock induced melting of the breccia and injected and coated the rock with externally derived impact melts the coating glass is heterogeneous its average composition is similar to the compositions of other apollo 16 coating glasses except that its tio2 content is lower the vein glass is unusually mafic and has very low tio2 for its al2o3 content the tio2 contents of these glasses establish that they cannot be melted soils their compositions require a mafic low tio2 protolith component that has not yet been identified among the large rock samples perhaps a very mafic member of the ferroan anorthosite suite

chronology of dimict breccias and the age of south ray crater at the apollo 16 site we report the noble gas isotopic abundances of five dimict breccias and one cataclastic anorthosite that were collected at the apollo 16 landing site orbital and surface photographs indicate that rays from south ray crater an almost 1 km wide young crater in the cayley plains extend several kilometers from their source into the area that was sampled by the apollo 16 mission previous studies have shown that south ray crater formed 2 ma ago and that a large number of rocks might originate from this cratering event on the basis of cosmic ray produced nuclei we find that the six rocks investigated in this work yield the same lunar surface exposure age using literature data we recalculate the exposure ages of additional 16 rocks with suspected south ray crater origin and obtain an average exposure age of 2 01 0 10 ma in particular all nine dimict breccias a type of rock essentially restricted to the apollo 16 area consisting of anorthosite and breccia phases dated until now yield an average ejection age of 2 06 0 17 ma we conclude that they must originate from the cayley formation or from bedrock underlying the cayley plain we determined the gas retention ages for the dimict breccias based on the 40k 40ar and u th 136xe dating methods rock 64425 yields a 40k 40ar age of 3 96 ga and rock 61016 a u th 136xe age of 3 97 ga these results together with 39ar 40ar ages obtained by other workers for rocks 64535 3 98 ga and 64536 3 97 ga show that the dimict breccias formed 3 97 ga ago

source rock quality and hydrocarbon migration pathways within the greater utsira high area viking graben norwegian north sea the greater utsira high area is located within the southern part of quadrants 24 and 25 and the northern part of quadrants 15 and 16 in the norwegian north sea in this part of the viking graben the main exploration play is the submarine fan sands of paleocene and eocene age these sands balder heimdal and ty formations pinch out to the east in blocks 25 8 jotun field and 25 11 balder and grane fields and along the western margin of the utsira high to form a combination of stratigraphic and structural traps marine sands of middle and late jurassic age typically present in rotated fault blocks constitute another important play geochemical analyses show that the upper jurassic draupne formation has a good potential for oil generation along the entire western margin and northern nose of the utsira high both upper and lower draupne source intervals along the western graben margin however contain more terrigenous kerogen than in the eastern part of the graben such change in organic facies within the draupne source interval naturally results in a higher proportion of gas generation and the possibility for generating a more waxy crude than typically encountered in the viking graben detection and characterization of oil and gas shows within the tertiary section permit mapping of migration entry points from the jurassic source rocks and help delineate secondary and tertiary migration pathways within the paleocene eocene play

interpreting rock eval pyrolysis data using graphs of pyrolizable hydrocarbons vs total organic carbon kerogen the major organic component of sedimentary rocks is commonly analyzed by rock eval pyrolysis plotting the data on a graph of s 2 vs total organic carbon toc and determining the regression equation is the best method for determining the true average hydrogen index and measuring the adsorption of hydrocarbon by the rock matrix such a plot also indicates the type of kerogen present and avoids the problem of increasing hydrogen index with total organic carbon content with the s 2 vs toc diagram the organic component of different suites of samples may be compared and their petroleum generation potentials established as an example the diagrams are used to evaluate the sedimentary environments and petroleum potential of the paleogene evaporitic sediments of the mulhouse basin alsace france

using stable isotope analysis δd δ18o to characterise the regional hydrology of the sierra de gador south east spain water stress is rapidly increasing in many mediterranean coastal zones mainly due to expansion in agriculture and tourism in this paper we focus on the sierra de gador campo de dalias aquifer system southeastern spain in order to assess the capability of water stable isotope analysis deltad delta 18 o to refine the understanding on recharge of this karstic aquifer system different types of surface and groundwater were sampled along an altitudinal gradient from the recharge zone in the mountains to the coastal plain surface water is restricted to local runoff collected in closed reservoirs runoff amounts collected in three of these reservoirs were monitored together with the precipitation in their catchments meteorological maps were used to detect the origin of the precipitation generating the majority of the runoff the results were compared to literature data on local and regional precipitation the use of oxygen and hydrogen isotopic composition has proved to be a useful tool to explain the origin of groundwater in a mediterranean karstic system such studies are however not numerous and are often limited to local scale recharge for fast reacting systems this paper focuses on the delta 18 o deltad relationships of local precipitation to explain the isotopic variability of a large karstic aquifer system the isotopic compositions of groundwater sampled along an altitudinal gradient from the recharge zone to the coastal plain are well displayed in a deltad delta 18 o diagram on a mixing line connecting a pole of mediterranean waters to a pole of atlantic waters the atlantic signature predominates in the shallow groundwater of natural springs reflecting the rainfall which produced the local runoff sampled the mediterranean signature is mainly restricted to deep groundwater from boreholes in the coastal plain the existence of a degree of spatial separation of groundwater types demonstrates that groundwater flow in a complex karstic system is not always continuous the mediterranean signature of deep groundwater could be due to past extreme rainfall events during which connectivity between recharge and reservoir exists while at the same time the atlantic signature of recent winter rains dominates in shallow groundwater the assumption that an equilibrium in isotopic composition is established within a continuous aquifer and that therefore a slope lower than 8 in a deltad delta 18 o diagram indicates evaporation is not necessarily valid c 2002 elsevier science b v all rights reserved

holocene forcing of the indian monsoon recorded in a stalagmite from southern oman a high resolution oxygen isotope record from a thorium uranium dated stalagmite from southern oman reflects variations in the amount of monsoon precipitation for the periods from 10 3 to 2 7 and 1 4 to 0 4 thousand years before the present ky b p between 10 3 and 8 ky b p decadal to centennial variations in monsoon precipitation are in phase with temperature fluctuations recorded in greenland ice cores indicating that early holocene monsoon intensity is largely controlled by glacial boundary conditions after approximately 8 ky b p monsoon precipitation decreases gradually in response to changing northern hemisphere summer solar insolation with decadal to multidecadal variations in monsoon precipitation being linked to solar activity

cratering history and lunar chronology the moon is exceptional and important because it is the only planetary body besides the earth for which we have both a detailed stratigraphic history and datable rock samples that can be related to specific geomorphologic units fig 5 1 the moon has preserved much of its magmatic and impact record of at least the last 4 billion years while its endogenic history is of great interest for the fundamentals of planetary interiors and surfaces the moon has become a calibration plate for the cratering record of the earth moon system and by extrapolation of the entire inner solar system if one assumes a heliocentric origin for impactor populations these populations range from asteroids through long and short period comets to interplanetary dust and cover a size range from hundreds of kilometers to micrometers figure 5 1 telescopic view of the nearside of the earth s moon with landing sites of the apollo and luna missions this chapter reviews the presently available data sets in support of this paradigmatic assumption as follows 1 the phenomenology of lunar impact craters 2 the terrestrial record of the impact cratering process and the interpretation of terrestrial impactites as far as this ground truth is relevant for the interpretation of lunar impact craters and datable lunar impact breccias and melt rocks 3 the theory and numerical simulation of the cratering process and the characteristics of the earth moon crossing population of impactors asteroids and comets 4 the principles of relative age dating of lunar surface units and the general lunar stratigraphy 5 the stratigraphic significance and ages of lunar samples impactites and basalts and based on this data set the absolute ages of lunar surface units 6 the cratering rate of the moon as a function of time and 7 the time calibration of this cratering rate based on the

sedimentology and sequence stratigraphy of a transfer zone coarse grained delta miocene suez rift egypt this study focuses on miocene sedimentation and stratigraphic evolution in a major transfer zone at the northern tip of the thal fault segment gulf of suez the succession generally shoals upwards from offshore mudstone containing pro delta turbidites into conglomeratic delta foresets and topsets with sandstone dominated shoreface facies coexisting laterally despite this upward shoaling key stratal surfaces marking abrupt changes in relative sea level allow the succession to be divided into four stratal units the stacking pattern of the stratal units suggests an initial relative sea level rise that generated a major marine flooding surface a relative sea level fall followed resulting in widespread exposure and incision during the ensuing relative sea level rise a lowstand coarse grained delta and coeval shoreface succession prograded several kilometres basinward the stratigraphic development of the transfer zone delta is in marked contrast to that of aggradationally stacked deltas that occur near the centre of the baba sidri fault segment further south at the transfer zone low rates of subsidence and accommodation development coupled with a high sediment supply derived from a large fault tip drainage catchment have produced a strongly progradational delta subject to marked changes in relative sea level in the fault centre location however higher rates of accommodation development coupled with lower rates of sediment supply from footwall catchments have produced aggradationally stacked deltas the results from this study have implications for sequence stratigraphic models and hydrocarbon exploration within extensional basins

the role of seasonality in abrupt climate change abstract a case is made that seasonality switches dominated by wintertime were instrumental in abrupt climate changes in the north atlantic region during the last glaciation and into the holocene the primary evidence comes from mismatches between mean annual temperatures from greenland ice cores in comparison with snowline changes in east greenland northern europe and north america the most likely explanation is a shutdown or reduction in strength of the conveyor this allows the spread of winter sea ice across the north atlantic thus causing the northern region to experience much colder winters because they mimic the greenland temperature rather than the snowline signal changes in the atlantic intertropical convergence zone and the asian monsoon may also share a winter linkage with greenland thus the paleoclimate record is consistent with the notion that a huge continental sector of the northern hemisphere stretching from greenland to asia was close to an extreme winter threshold during much of the last glaciation winter climate crossed this threshold repeatedly with marked changes in seasonality that may well have amplified and propagated a signal of abrupt change throughout the hemisphere and into the tropics

dating small fresh lunar craters with mini rf radar observations of ejecta blankets 1 the ages of large impact craters on the moon can be estimated by measuring the size frequency distribution of smaller craters superimposed on their ejecta but applying this method to individual craters under 3 km in diameter remains difficult due to their limited areal extent the ejecta blankets of fresh lunar impact craters are expressed as halos of optical and radar bright material that gradually fade with time although compositional differences make inferring crater ages from optical albedo problematic radar is less sensitive to composition and thus may provide a more reliable means of estimating age in this work we use radar data from the miniature radio frequency mini rf instrument on the lunar reconnaissance orbiter lro to characterize the radar backscatter of large numbers of ejecta blankets by analyzing the size frequency distribution of these craters we show that the lifetime of the radar bright discontinuous ejecta blanket varies with crater diameter in a predictable way for craters with diameters between 0 45 and 5 km absolute ages of individual craters can then be estimated by combining this empirically derived model with estimates of the relative degradation state of each individual crater the lifetimes of radar bright discontinuous ejecta blankets are significantly shorter in the highlands than the maria although this is likely due to local topography creating difficulties in applying the method to the highlands the cosmic ray exposure age of south ray crater a fresh crater visited by apollo 16 provides confirmation of these results this method therefore provides a new way to accurately date small fresh craters using the mini rf data set

isotopic composition of precipitation in italy a first overall map abstract composite monthly samples of atmospheric precipitation were collected over different periods of time ranging from one to seven years at 77 different locations throughout italy these samples were measured for their oxygen and hydrogen isotopic composition to obtain basic information for hydrological and meteorological studies in this area on the basis of the results obtained a first map of the isotopic composition of precipitations in italy has been drawn up the main features of this map are the following 1 no isotopic latitudinal gradient has been found along the tyrrhenian coast from sicily to the italian french border despite the considerable range of latitude 2 a minor latitudinal gradient is found in the southeasternmost section of the country apulia partially favored by the local morphology 3 a marked shadow effect of the apennines is apparent along the southern section of the po valley and along the central section of the adriatic coast 4 the contribution of water vapor from the northernmost section of the adriatic sea affects the eastern and central sections of the po plain 5 the shadow effect of the alps is considerably smaller than expected 6 the isotopic vertical gradients calculated in nine different areas and based on groups of two to five different stations vary but are essentially close to about 0 2 100 m 7 when mean monthly temperature values were available their relationship with the isotopic composition of precipitation was found to be on average very poor 8 the relationship between mean 18o and mean d calculated for the collection locations shows shifts of both the slope and the deuterium excess when compared to the global meteoric water line these shifts are different for northern central and southern italy 9 in a few cases anomalously low monthly values suggest the existence of pronounced amount effects

speleothem δ13c record suggests enhanced spring summer drought in south eastern spain between 9 7 and 7 8 ka a circum western mediterranean anomaly south eastern spain is one of the driest regions in europe and thus prone to drought terrestrial climate records covering the late glacial and holocene from this area are sparse here we present