a high resolution record of the last deglaciation in the central mediterranean sea palaeovegetation and palaeohydrological evolution abstract a high resolution palynological and stratigraphical record of a marine deep sea core in the adriatic sea documents marine and continental palaeoenvironmental changes in the basin during the last deglaciation and early holocene a chronology is derived from the oxygen isotope stratigraphy three periods of aridity marked by the development of a semi desert rich in artemisia occurred between 18 5 and 16 kyr between 14 4 and 12 7 kyr and between 11 1 and 9 7 kyr consistent with the last glacial maximum the oldest dryas and the younger dryas they are correlated with increases in productivity and intensification of the levantine water formation in the eastern mediterranean basin during the warmer bolling allerod 12 7 11 1 kyr the presence of the cold temperate dinocyst bitectatodinium tepikiense is interpreted as indicating the establishment of a strong seasonal thermal gradient probably linked to seasonal cold freshwater runoff from the po river attested by the unique presence of pollen of freshwater plants the expansion of forest and the development of the warmer dinocysts start with termination ib during the holocene three tree phases are recognized and are contemporaneous with the preboreal boreal and atlantic chronozones of europe the two phases of sapropel deposition are marked by higher pollen and dinocyst concentrations and a high representation of brigantedinium spp which indicate higher preservation of organic material and or freshwater runoff of the po river

late glacial to holocene planktic foraminifera bioevents and climatic record in the south adriatic sea quantitative analyses of planktic foraminifera sea surface temperatures ssts oxygen isotope and radiocarbon dating from a deep sea core recovered in the south adriatic sea have been used to reconstruct a subcentennial climatic and biochronological record since the late glacial the last 24 cal ka bp the identification and relative abundance of 25 species of planktic foraminifera along the core have provided a continuous record of the faunal changes over this time interval these results have permitted the establishment of 10 biozones in the south adriatic sea based on the appearance and or disappearance of the main specific taxa from peaks of abundance and or by modification in marine conditions the robust chronology of the south adriatic core allowed correlation of sst estimates to the gisp2 ice core record indicating that the main climate changes recorded in greenland ice cores over the last 24 ka are recorded and globally synchronous with those observed in the south adriatic sea this finding further allows comparison of the planktic foraminifera record with the event stratigraphic scheme proposed by the intimate group in order to better identify the relationship between past climatic changes and the response of microfaunal assemblages in the south adriatic copyright 2010 john wiley sons ltd

mapping geochemical anomalies related to fe polymetallic mineralization using the maximum margin metric learning method abstract geochemical anomaly identification is an important task in mineral exploration targeting this task can be regarded as a binary classification problem whereby the aim is to discriminate between anomalous and not anomalous i e background we can analyze geochemical data from the aspects of frequency distributions correlations and variances geometrical properties of geochemical anomalies and scale independence of geochemical patterns in this study we recognize geochemical anomalies based on the intrinsic relationship between geochemical elements which can be addressed by measuring their separation distance as a machine learning method metric learning aims at exploiting the statistical information between the geochemical features in limited training samples and developing a more suitable distance to evaluate the similarity of samples without priori distribution assumptions accordingly a metric learning method based on the maximum margin frame was applied to identify multivariate geochemical anomalies related to fe polymetallic mineralization in the southwestern fujian province of china the geochemical exploration data were firstly translated into a dimensional reduced subspace with the help of maximum margin metric learning mmml the adaptive coherence estimator ace detector from the field of target detection was then employed to identify geochemical anomalies the anomaly results obtained by this integrated procedure using a combination of mmml and ace were compared to those obtained by ace without metric learning using a receiver operating characteristic roc curve the area under the curve value implied superior performance using the combination of mmml and ace suggesting that this hybrid method can be effectively applied to recognize geochemical anomalies linked to mineralization

microseismic measurement of wave energy delivery to a rocky coast rocky coasts are attacked by waves that drive sea cliff retreat and etch promontories and embayments into the coastline understanding the evolution of such coastlines requires knowledge of the energy supplied by waves which should depend upon both the deep water waves and the coastal bathymetry they cross we employ microseismic measurements of the wave induced shaking of sea cliffs near santa cruz california as a proxy for the temporal pattern of wave energy delivery to the coast during much of the winter 2001 storm season visual inspection of the time series suggests that both deep water wave heights and tide levels exert considerable control on the energy delivered we test this concept quantitatively with two models in which synthetic time series of wave power at the coast are compared with the shaking data in the first model deep water wave power is linearly scaled by a fitting parameter because this model fails to account for the strong tidal signal it fits poorly in the second model the wave transformation associated with shoaling and refraction diminishes the nearshore wave power and dissipation associated with bottom drag and wave breaking is parameterized by exponential dependencies on two length scales this model reduces the variance by 32 45 and captures the essence of the full signal shoaling and refraction greatly modulate the wave power delivered to the coast energy dissipated by bottom drag across the shelf is relatively small the dissipation length scale is many times the path length across the shelf in contrast much energy is dissipated in the surf zone the tidal dissipation depth scale is of the same order as the tidal range 1 2 m which accounts for the strong dependence of the cliff shaking on the tide

surface based transport model for mixed size sediment we present a transport model for mixed sand gravel sediments fractional transport rates are referenced to the size distribution of the bed surface rather than subsurface making the model completely explicit and capable of predicting transient conditions the model is developed using a new data set of 48 coupled observations of flow transport and bed surface grain size using five different sediments the model incorporates a hiding function that resolves discrepancies observed among earlier hiding functions the model uses the full size distribution of the bed surface including sand and incorporates a nonlinear effect of sand content on gravel transport rate not included in previous models the model shares some common elements with two previous surface based transport models but differs in using the full surface size distribution and in that it is directly developed from a relatively comprehensive data set with unambiguous measurement of surface grain size over a range of flow transport rate and sediments

fractal modeling and fry analysis of the relationship between structures and cu mineralization in saveh region central iran abstract the saveh region in the middle part of the urumieh dokhtar magmatic belt udmb central iran contains several cu mineralization and deposits that may have been localized by structural controls in the region along the major thrust fault the saveh region comprises intrusive bodies associated with various cu occurrences and deposits the nw se major faults especially the khalkhab and koshk e nosrat faults on the iranian plates created a sigmoid space for the emplacement of plutons during middle eocene the cu occurrences deposits are either vein or manto style with vein style being dominant the lineaments and faults in the saveh region were mapped using precise local data including remote sensing landsat etm digital elevation models dem geomagnetic airborne images geological maps and field observations the relationship between cu occurrences deposits and geological structures the latter being described by a lineament factor lf or fracture density is important for focusing of ore forming fluids and mineralization this was analyzed by concentration area c a fractal modeling and by fry analysis the results of the c a fractal modeling and fry analysis indicate that the vein style cu mineralization is associated with major nw se trending faults especially the khalkhab and koshk e nosrat faults manto style cu mineralization in the saveh region is associated with minor ne sw trending faults

mediterranean sea surface radiocarbon reservoir age changes since the last glacial maximum sea surface reservoir ages must be known to establish a common chronological framework for marine continental and cryospheric paleoproxies and are crucial for understanding ocean continent climatic relationships and the paleoventilation of the ocean radiocarbon dates of planktonic foraminifera and tephra contemporaneously deposited over mediterranean marine and terrestrial regions reveal that the reservoir ages were similar to the modern one 400 years during most of the past 18 000 carbon 14 years however reservoir ages increased by a factor of 2 at the beginning of the last deglaciation this is attributed to changes of the north atlantic thermohaline circulation during the massive ice discharge event heinrich 1

spatiotemporal sequence of himalayan debris flow from analysis of high frequency seismic noise 1 during the 2003 summer monsoon the hi climb seismological stations deployed across the himalayan range detected bursts of high frequency seismic noise that lasted several hours to days on the basis of the cross correlation of seismic envelopes recorded at 11 stations we show that the largest transient event on 15 august was located nearby a village partially destroyed on that day by a devastating debris flow this consistency in both space and time suggests that high frequency seismic noise analysis can be used to monitor debris flow generation as well as the evacuation of the sediment a systematic study of one year of seismic noise focusing on the detection of similar events provides information on the spatial and temporal occurrence of mass movements at the front of the himalayas with a 50 probability of occurrence of a daily event a total of 46 debris flows are seismically detected most of them were generated in regions of steep slopes large gullies and loose soils during the 2003 summer monsoon storms these events are compared to local meteorological data to determine rainfall thresholds for slope failures including the cumulative rainfall needed to bring the soil moisture content to failure capacity the inferred thresholds are consistent with previous estimates deduced from soil studies as well as sediment supply investigations in the area these results point out the potential of using seismic noise as a dedicated tool for monitoring the spatiotemporal occurrence of landslides and debris flows on a regional scale

revisiting the y 3 tephrostratigraphic marker a new diagnostic glass geochemistry age estimate and details on its climatostratigraphical context the y 3 tephra is a crucial stratigraphic marker within the central mediterranean region that falls close to the marine isotope stage 3 2 transition and a cooling event proposed as a correlative of the north atlantic heinrich stadial 3 hs3 consequently this tephra offers great potential to assess any leads and lags in environmental responses to this abrupt climatic transition new grain specific glass analysis empa and la icp ms of the type locality y 3 tephra recorded in the ionian sea confirms its origin from campi flegrei cf but reveals that it is compositionally different from the previously suggested proximal equivalent the vra eruptive unit verdolino valley cf consequently the 40ar 39ar age of the vra should not be exported distally to the y 3 tephra instead we propose a new robust age for the y 3 tephra following its identification in the tenaghi philippon sedimentary record ne greece a bayesian based 14c age model from tenaghi philippon provides a distal age of 28 680 29 420 cal yrs bp for the y 3 tephra the identification of this tephra in ne greece markedly extends its known eastern dispersal whilst its stratigraphic position falls within the latter part of a period of low tree pollen percentages related to dry stadial conditions this new age and environmental context suggest that this marker postdates the onset of hs3 in the eastern mediterranean region by 2300 years

origin and consequences of cyclic ice rafting in the northeast atlantic ocean during the past 130 000 years deep sea sediment cores recovered from the northeast atlantic ocean were examined in order to elucidate the influence of the earth s orbital parameters on major ice rafting analyses of coarse grained ice rafted debris and planktonic foraminifers revealed a strong reaction to the precession signal since 130 000 yr b p dropstone layers have been deposited each half period of a precessional cycle 11 000 1000 yr ice rafting occurs during times of winter minimum summer maximum insolation and summer minimum winter maximum insolation in the first case high summer insolation forces meltwater discharge from the ice sheets into the polar seas which subsequently enhances formation of sea ice during the winter in the second case growth of continental ice enhances iceberg production which also leads to a salinity reduction of surface seawater both situations result in a southward penetration of polar water thus the marine record of dropstones documents ice rafting not only during weichselian stades but also during cold events within interstades the regularity of ice rafting yields a useful framework to calibrate and elucidate climatic changes not only in the region of the north atlantic ocean but also in remote areas such as the pacific ocean and the antarctic

effects of benthic transport processes on abrupt climatic changes recorded in deep sea sediments a time dependent modeling approach 1 a one dimensional time dependent model is developed to characterize qualitatively and quantitatively the combined effects of bioturbation and burial on sedimentary signals related to abrupt climatic changes this model is based on the widely used advection diffusion equation and simulates rapid climatic transitions by representing the deposition flux at the sediment water interface by a steep ramp function of time this model is applied to both planktonic foraminifera abundance curves and 18o distributions output signals obtained at the bottom of the bioturbated layer for these rapid transitions have been generated for a broad range of sedimentation rates 5 50 cm kyr 1 biodiffusion coefficients 10 3 1 cm2 yr 1 and mixed layer thicknesses 2 15 cm numerical results clearly demonstrate the importance of a dynamic description of sediment mixed layers properties of the sedimentary response to fast transitions appear to be highly and nonlinearly dependent upon the sedimentation rate and the relative values of the original transition length and the time required to bury the signal below the mixed layer moreover for low sedimentation rates 10 cm kyr 1 we show that signals occurring over a 50 to a 250 year timescale are indistinguishable to quantify the distortion of sedimentary signals we determined the transition length of the bioturbated simulated signals and compare it to the initial transition length for given sets of bioturbation and sedimentation rates and mixed layer thicknesses comparison between model predictions and experimental results reveals a good agreement showing that transition timescales are compatible with ice core derived transitions 100 years for environments in which bioturbation can be approximated by a diffusive process tests performed on 18o distributions have illustrated the effect of bioturbation on the stratigraphic offsets between isotopic compositions of cold and warm species of foraminifera during climatic transitions

analysis of rock fall and rock fall avalanche seismograms in the french alps this study reviews seismograms from 10 rock fall events recorded between 1992 and 2001 by the permanent seismological network sismalp in the french alps a new seismic magnitude scale was defined which allowed us to compare and classify g round motion vibrations generated by these alpine rock falls each rock fall has also been cha racterized by its ground motion duration t30 at an epicentral distance of 30 km no relation was found between rock fall parameters fall height runout distance volume potential energy and rock fall s eismic magnitudes derived from seismogram amplitudes on the other hand the signal duration t30 shows a rough correlation with the potential energy and the runout distance highlighting the co ntrol of the propagation phase on the signal length the signal analysis suggests the existence of at le ast two distinct seismic sources one corresponding to the initial rupture associated with an elastic r ebound during the detachment and the other one generated by the rock impact on the slope although the fall phenomenon includes other complex processes fragmentation of the block interaction with topography plastic deformation during and after impact 2d finite element simulations of thes e two seismic sources are able to retrieve the main seismogram characteristics

reconstruction of the last deglaciation deconvolved records of δ18o profiles micropaleontological variations and accelerator mass spectrometric14c dating bioturbation acts as a low pass filter in displacing and reducing the amplitudes of stratigraphic signals this often leads to a loss of high frequency events in the stratigraphic record in addition when considering an isotopic signal 18o 14c measured in stratigraphic carriers such as foraminifera bioturbation and carrier abundance changes can create artifacts which may be falsely interpreted as leads or lags in the paleoclimatic record

chronology for climate change developing age models for the biogeochemical ocean flux study cores we construct age models for a suite of cores from the northeast atlantic ocean by means of accelerator mass spectrometer dating of a key core bofs 5k and correlation with the rest of the suite the effects of bioturbation and foraminiferal species abundance gradients upon the age record are modeled using a simple equation the degree of bioturbation is estimated by comparing modeled profiles with dispersal of the vedde ash layer in core 5k and we find a mixing depth of roughly 8 cm for sand sized material using this value we estimate that age offsets between unbioturbated sediment and some foraminifera species after mixing may be up to 2500 years with lesser effect on fine carbonate 10 mu m ages the bioturbation model illustrates problems associated with the dating of instantaneous events such as ash layers and the heinrich peaks of ice rafted detritus correlations between core 5k and the other cores from the bofs suite are made on the basis of similarities in the downcore profiles of oxygen and carbon isotopes magnetic susceptibility water and carbonate content and via marker horizons in x radiographs and ash beds

gravel transport and morphological change in braided sunwapta river alberta canada the relation between morphological change and patterns of variation in bedload transport rate in braided streams was observed by repeated daily topographic surveys over a 25 day study period in a 60 m reach of the proglacial sunwapta river alberta canada there are two major periods of morphological change each lasting several days and each involving the complete destruction and reconstruction of bar complexes bar complex destruction was caused by redirection of the flow and by downstream extension of the confluence scour zone upstream reconstruction involved accretion of unit bars on bar head flank and tail and in one case was initiated by disection of a large lobate unit bar high rates of sediment movement measured from net scour and fill of the cross sections coincided with these morphological changes sediment was supplied from both bed and bank erosion and patterns and distances of transfer were highly variable rates of transport estimated by matching upstream erosional volumes with downstream deposition were much greater than those estimated from either a step length approach or a sediment budget measurements of scour and fill and observations of morphological change indicate that step lengths virtual transport distances were typically 40 100m during a diurnal discharge cycle shorter step lengths occurred when transfer was confined to a single anabranch and longer steps involved channel changes at the scale of the entire reach sediment budgeting was used to describe the spatial patterns of sediment transport associated with the morphological changes and to estimate minimum daily reach averaged transport rates mean bedload transport rates correlate with discharge but with considerable scatter the largest deviations from the mean relation can be tied to phases of channel incision bank erosion scour hole migration bar deposition and channel filling apparently controlled by changes and fluctuations in sediment supply from upstream independent of discharge these are interpreted as field evidence of autopulses or macropulses in bedload transport previously observed only in laboratory models of braided streams

assessing geochemical anomalies using geographically weighted lasso abstract geochemical patterns in the surficial media are complex because of the various processes involved in their formation these processes may or may not relate to mineralization therefore geochemical anomalies identified are usually subject to uncertainty geographically weighted lasso gwl was adopted in this study to model the non stationary relationships between the geological geographical features and geochemical patterns in the surficial media the sparsity and reliability of regression coefficients in the gwl modeling renders it suitable for quantifying the controls that geological geographical features have on geochemical patterns this information can improve current knowledge about the complexity of geochemical patterns a case study in which the gwl model was established between geological geographical variables and the geochemical patterns of cu observed in stream sediments in the southwestern fujian province of china was presented the following findings were obtained 1 geological features show a major control on the geochemical patterns of cu in the studied area however the geochemical patterns of cu have been modified to some extent by secondary processes resulting in the relationships between geochemical signatures and mineralization becoming more complex and uncertain and 2 the gwl modeling can provide useful information for evaluating geochemical anomalies which can help reduce the uncertainty and benefit geochemical exploration at a later stage

timing and dynamics of the last deglaciation from european and north african δ13c stalagmite profiles comparison with chinese and south hemisphere stalagmites abstract the last deglaciation and its climatic events such as the bolling allerod ba and the younger dryas yd have been clearly recorded in the 13 c profiles of three stalagmites from caves from southern france to northern tunisia the three 13 c records dated by thermal ionization mass spectrometric uranium thorium method tims show great synchroneity and similarity in shape with the chinese cave 18 o records and with the marine tropical records leading to the hypothesis of an in phase between 15 5 and 16 ka 0 5 ka postglacial warming in the northern hemisphere up to at least 45 n the ba transition appears more gradual in the speleothem records than in the greenland records and the allerod seems warmer than the bolling showing here close similarities with other marine and continental archives a north south gradient is observed in the ba trend it cools in greenland and warms in our speleothem records several climatic events are clearly recognizable a cooler period at about 14 ka older dryas od the intra allerod cold period at about 13 3 ka the yd cooling onset between 12 7 and 12 9 0 3 ka similar to the ba the yd displays a gradual climate amelioration just after its onset at 12 75 0 25 ka up to the preboreal and is punctuated by a short climatic event at 12 15 ka even though the southern hemisphere stalagmite records seem to indicate that the postglacial warming started about 3 ka 1 8 ka earlier in new zealand 41 s and about 1 to 2 ka earlier in south africa 24 1 s large age uncertainties essentially due to slow growth rates make the comparison still perilous the overall 13 c speleothem record seems to follow a baseline temperature increase controlled by the increase in insolation and punctuated by cold events possibly due to the n america freshwater lake discharges

recognition of geochemical anomalies using a deep variational autoencoder network abstract deep learning dl algorithms have received increased attention in various fields in the field of geoscience dl has been shown to be a powerful tool for mining complex high level and non linear geospatial data and for extracting previously unknown patterns related to geological processes in this study a deep variational autoencoder vae network was used to extract features related to mineralization and these features were then integrated as a anomaly map in support of mineral exploration based on geochemical exploration data which consist of cu pb mn zn and fe2o3 various experiments were conducted to determine the optimal parameters of the vae the structure of the vae in which the network depth and number of hidden units were 24 12 3 12 24 was built to recognize geochemical anomalies related to fe polymetallic mineralization in the southwest fujian province china the geochemical anomalies recognized by the vae show a close spatial correlation with known fe polymetallic deposits meanwhile the areas with high probability are located in or around the yanshanian intrusions and the contact zones of the carboniferous permian formation and yanshanian intrusions these results suggest that the anomalous areas identified by the vae are meaningful for mineral exploration

integrating timescales with time transfer functions a practical approach for an intimate database the purpose of the intimate project is to integrate palaeo climate information from terrestrial ice and marine records so that the timing of environmental response to climate forcing can be compared in both space and time one of the key difficulties in doing this is the range of different methods of dating that can be used across different disciplines for this reason one of the main outputs of intimate has been to use an event stratigraphic approach which enables researchers to co register synchronous events such as the deposition of tephra from major volcanic eruptions in different archives blockley et al 2012 however this only partly solves the problem because it gives information only at particular short intervals where such information is present between these points the ability to compare different records is necessarily less precise chronologically what is needed therefore is a way to quantify the uncertainties in the correlations between different records even if they are dated by different methods and make maximum use of the information available that links different records this paper outlines the design of a database that is intended to provide integration of timescales and associated environmental proxy information the database allows for the fact that all timescales have their own limitations which should be quantified in terms of the uncertainties quoted it also makes use of the fact that each timescale has strengths in terms of describing the data directly associated with it for this reason the approach taken allows users to look at data on any timescale that can in some way be related to the data of interest rather than specifying a specific timescale or timescales which should always be used the information going into the database is primarily proxy information principally from sediments and ice cores against depth age depth models against reference chronologies typically intcal or ice core and time transfer functions that relate different timescales to each other through the use of event stratigraphies or global phenomena such as cosmogenic isotope production rate variations

subglacial discharge at tidewater glaciers revealed by seismic tremor subglacial discharge influences glacier basal motion and erodes and redeposits sediment at tidewater glacier termini discharge drives submarine terminus melting affects fjord circulation and is a central component of proglacial marine ecosystems however our present inability to track subglacial discharge and its variability significantly hinders our understanding of these processes here we report observations of hourly to seasonal variations in 1 5 10 hz seismic tremor that strongly correlate with subglacial discharge but not with basal motion weather or discrete icequakes our data demonstrate that vigorous discharge occurs from tidewater glaciers during summer in spite of fast basal motion that could limit the formation of subglacial conduits and then abates during winter furthermore tremor observations and a melt model demonstrate that drainage efficiency of tidewater glaciers evolves seasonally glaciohydraulic tremor provides a means by which to quantify subglacial discharge variations and offers a promising window into otherwise obscured glacierized environments

the reset project constructing a european tephra lattice for refined synchronisation of environmental and archaeological events during the last c 100 ka this paper introduces the aims and scope of the reset project response of humans to abrupt environmental transitions a programme of research funded by the natural environment research council uk between 2008 and 2013 it also provides the context and rationale for papers included in a special volume of quaternary science reviews that report some of the project s findings reset examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions aets on the one hand and of human dispersal and development on the other with a focus on the middle and upper palaeolithic periods the period of interest is the last glacial cycle and the early holocene c 100 8 ka during which time a number of pronounced aets occurred a long running topic of debate is the degree to which human history in europe and the mediterranean region during the palaeolithic was shaped by these aets but this has proved difficult to assess because of poor dating control in an attempt to move the science forward reset examined the potential that tephra isochrons and in particular non visible ash layers cryptotephras might offer for synchronising palaeo records with a greater degree of finesse new tephrostratigraphical data generated by the project augment previously established tephra frameworks for the region and underpin a more evolved tephra lattice that links palaeo records between greenland the european mainland sub marine sequences in the mediterranean and north africa the paper also outlines the significance of other contributions to this special volume collectively these illustrate how the lattice was constructed how it links with cognate tephra research in europe and elsewhere and how the evidence of tephra isochrons is beginning to challenge long held views about the impacts of environmental change on humans during the palaeolithic

west african lateritic pediments landform regolith evolution processes and mineral exploration pitfalls this paper is a contribution to the understanding of surface dynamics of tropical shields over geological timescales emphasis is put on the fundamental and applied implications of regolith production and dispersion processes through the formation dissection and preservation of landforms it is based on the case study of sub saharan west africa which recorded neogene 24 3 ma stepwise dissection of its topography through the emplacement of three lateritic pediment systems which still occupy most of its surface pediments are erosional transportation slopes having been weathered and duricrusted pediment regolith associations therefore depend on the parent rock transport dynamics and preservation of the material having transited on their surface as well as on the intensity of their weathering duricrusting iron oxy hydroxide cemented clastic sediments detrital ferricretes and unconsolidated clastic sediments are the dominant outcropping material and as such represent a challenge for mineral exploration that relies on surface geochemical sampling to detect metal concentration in the bedrock landform regolith mapping beyond the scale of modern interfluves combined with paleolandscape reconstitution are relevant to provide exploration guides for i interpreting geochemical anomalies on pediments ii tracing their potential source when they have been transported on pediments and iii targeting suspected ore bodies concealed beneath pediment s past and present latitudinal climatic zonation of pedimentation and weathering patterns suggests a gradation of pedimentation process across the intertropical zone and explains why pediments may have been overlooked in equatorial environments with implications for mineral exploration successive pediment systems adapted to uneven knickzone bearing river networks producing a spatially consistent and reduced 80 m stepping pattern of pediments independent from elevation or distance to base level pediments pediplains are therefore not proxies of uplift and their preservation over geological timescales typifies regions submitted to 10 m my erosion rates the identification and study of lateritic pediments bear important implications on shield sediment routing systems and a better access to the bedrock and its resources which may still be underestimated in the tropics

rapid environmental changes in southern europe during the last glacial period oxygen isotope records from greenland ice cores1 2 indicate numerous rapid climate fluctuations during the last glacial period north atlantic marine sediment cores show comparable variability in sea surface temperature and the deposition of ice rafted debris3 4 5 in contrast very few continental records of this time period provide the temporal resolution and environmental sensitivity necessary to reveal the extent and effects of these environmental fluctuations on the continents here we present high resolution geochemical physical and pollen data from lake sediments in italy and from a mediterranean sediment core linked by a common tephrochronology our lacustrine sequence extends to the past 102 000 years many of its features correlate well with the greenland ice core records demonstrating that the closely coupled ocean atmosphere system of the northern hemisphere during the last glacial4 extended its influence at least as far as the central mediterranean region numerous vegetation changes were rapid frequently occurring in less than 200 years showing that the terrestrial biosphere participated fully in last glacial climate variability earlier than 65 000 years ago our record shows more climate fluctuations than are apparent in the greenland ice cores together the multi proxy data from the continental and marine records reveal differences in the seasonal character of climate during successive interstadials and provide a step towards determining the underlying mechanisms of the centennial millennial scale variability

first integrated tephrochronological record for the last 190 kyr from the fucino quaternary lacustrine succession central italy we present the first integrated tephrochronological study major and trace elemental glass composition sr and nd isotope analyses and 40ar 39ar dating for the last one tenth 82 m of the 900 m thick quaternary lacustrine succession of the fucino basin the largest and probably only central apennine intermountain tectonic depression that hosts a continuous lacustrine succession documenting the plio quaternary sedimentary history up to historical times major element glass compositions determined using a wavelength dispersive electron microprobe wds empa yielded the geochemical fingerprinting needed for a reliable identification of most of the 23 stratigraphically ordered tephra layers under investigation these include tephra from italian volcanoes such as campi flegrei etna colli albani ischia vico sabatini and undefined volcanic sources in the neapolitan area and latium region the recognition of key mediterranean marker tephra layers e g x 5 and x 6 is supported by trace element data acquired by laser ablation inductively couple plasma mass spectrometry la icp ms the sr and nd isotope compositions of selected layers where also determined for circumscribing the volcanic source of distal tephra and for supporting correlations with individual eruptive units we also propose a new more expeditious covariation diagram cao feotot vs cl for identifying the volcanic source of trachytic to phonolitic and tephrytic to phonolitic tephra that are the most common compositions of pyroclastic rocks from volcanoes of campania and latium regions finally we present five new 40ar 39ar age determinations including a new analytically well supported and more precise 40ar 39ar age for the widespread y 7 tephra and the first 40ar 39ar age determinations for one tephra from the sabatini volcanic district 126 ka and one tephra from neapolitan volcanic area campi flegrei 159 ka these newly dated tephra are widely dispersed e g monticchio southern italy adriatic sea and lake ohrid macedonia abania and have thus the potential to become important mediterranean mis 5 and mis 6 tephrochronological markers altogether the new geochemical data and 40ar 39ar ages precisely constrain the chronology of the investigated fucino succession spanning the last 190 ka in light of these results and by considering that this sedimentary succession possibly extends back to 2 ma fucino is likely to provide a very long continuous tephrostratigraphic record for the mediterranean area and become a key node in the dense network of tephra correlations of this region

improved age estimates for key late quaternary european tephra horizons in the reset lattice abstract the research project response of humans to abrupt environmental transitions reset used tephra layers to tie together and synchronise the chronologies of stratigraphic records at archaeological and environmental sites with the increasing importance of tephra as chronological markers in sedimentary sequences both in this project and more generally comes a requirement to have good estimates for the absolute age of these volcanic horizons this paper summarises the chronology of the key tephra in the reset tephra lattice in the time range 10 60 ka bp from the existing literature from papers produced as part of the reset project and reanalysis conducted for this paper the paper outlines the chronological approach taken to the dating of tephra within the reset project and the basis for further work as part of the intimate integrating ice core marine and terrestrial records initiative for each of the tephra layers in the lattice the existing literature is discussed and where relevant date estimates updated using the latest radiocarbon calibration curves intcal13 and marine13 and methods maps show the approximate extent of tephra finds giving a visual indication of the coverage of the lattice in different time periods

orbital and millennial antarctic climate variability over the past 800 000 years a high resolution deuterium profile is now available along the entire european project for ice coring in antarctica dome c ice core extending this climate record back to marine isotope stage 20 2 800 000 years ago experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation we assessed the general correspondence between dansgaard oeschger events and their smoothed antarctic counterparts for this dome c record which reveals the presence of such features with similar amplitudes during previous glacial periods we suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records

middle to late pleistocene activity of the northern matese fault system southern apennines italy abstract an integrated investigation including geological geomorphological geophysical and structural survey tephra analyses 14c and 40ar 39ar dating as well as paleoseismic trenching along the n matese fault system is presented the study allowed the characterization of the tectonic mobility of this structure as well as the associated bojano basin sedimentary tectonic evolution since the early middle pleistocene providing also new clues concerning the fault historical activity and the associated mw 6 5 earthquakes we have found lines of evidence for 1 mm yr slip rate along the presently buried bojano fault during the mid middle pleistocene and similar rates for the main fault segments paralleling the matese flanks the buried bojano fault significantly slowed down during the last 300 kyr ceasing its activity before the holocene in turn the segments outcropping along the matese flanks reactivated at the onset of late pleistocene after a long period of quiescence 480 110 ka with robust slip rates that would seem even accelerating in post lgm times paleoseismic data suggest the occurrence of four mw 6 6 earthquakes in the past 3 ka three of which match the little known 280 bc event and the devastating 1456 and 1805 earthquakes

ice age terminations 230th dated oxygen isotope records of stalagmites from sanbao cave china characterize asian monsoon am precipitation through the ends of the third and fourthmost recent ice ages as a result am records for the past four glacial terminations can now be precisely correlated with those from ice cores and marine sediments establishing the timing and sequence of major events in all four cases observations are consistent with a classic northern hemisphere summer insolation intensity trigger for an initial retreat of northern ice sheets meltwater and icebergs entering the north atlantic alter oceanic and atmospheric circulation and associated fluxes of heat and carbon causing increases in atmospheric co2 and antarctic temperatures that drive the termination in the southern hemisphere increasing co2 and summer insolation drive recession of northern ice sheets with probable positive feedbacks between sea level and co2

seismic monitoring of an alpine mountain river the canfranc underground laboratory lsc excavated under the central pyrenees is mainly devoted to the study of phenomena which needs cosmic silence it also hosts a geodynamical facility named geodyn which holds an accelerometer a broadband seismometer and two high resolution laser strainmeters during the routine processing of the seismic data we detected an unusual spectral signature in the 2 10 hz frequency band which does not correspond to the typical sources of seismic noise and which can also be recognized in the strain records after checking against meteorological and hydrological data we can relate those signals to variations in the discharge by the aragon river an alpine style river in the southern pyrenees located about 400 m from the lsc geodyn facility four main episodes have been identified since early 2011 each lasting 1 2 to 6 8 days additionally a limited number of shorter episodes have also been detected three types of river generated seismic events have been identified related respectively to moderate rainfall snowmelt and flooding events associated to severe storms each of those types has distinctive characteristics which allow monitoring the hydrological events from the analysis of seismic and deformation data a few previous studies have already described the seismic noise close to rivers with larger discharge or in small scale experimental settings and we are showing here that the so called fluvial seismology can be useful to study the hydrological evolution of alpine style streams and may have a potential interest for the civil authorities in charge of the management of hydrological basins

last deglaciation in the central balkan peninsula geochronological evidence from the jablanica mt north macedonia several studies applied numerical age determination methods to examine glacial phases of the central balkan peninsula however the resulting datasets are contradictory meaning that further discussion is needed this study provides 10 be cosmic ray exposure cre ages of a succession of glacial landforms in the jablanica mt north macedonia aiming at a better understanding of late pleistocene glacier development in the area on the basis of the mapped glacial landforms six glacial stages were identified and their mean equilibrium line altitudes elas were estimated the cre ages of five glacial stages from the second oldest to the youngest were determined between 16 8 0 8 0 5 ka and 13 0 0 4 0 9 ka accordingly the most extensive glaciation in the jablanica mt occurred before 17 ka the average ela of the glaciers was 1792 18 m a s l during the largest ice extent and 2096 18 m during the last phase of the deglaciation independent reconstructions of key climatic drivers of glaciological mass balance suggest that glacial re advances during the deglaciation were associated to cool summer temperatures before 15 ka the last glacial stillstand apparently resulted from a modest drop in summer temperature coupled with increased winter snow accumulation in the study area no geomorphological evidence for glacier advance after 13 0 4 0 9 ka could be found on the basis of independent climate proxies we propose that the last glacier advance occurred no later than 13 ka and glaciers were withdrawing during the younger dryas when low temperatures were combined with dry winters

timing and climatic impact of greenland interstadials recorded in stalagmites from northern turkey a 50 kyr long exceptionally well dated and highly resolved stalagmite oxygen 18o and carbon 13c isotope record from sofular cave in northwestern turkey helps to further improve the dating of greenland interstadials gi 1 and 3 12 timing of most gi in the sofular record is consistent within 10 to 300 years with the iconic hulu cave record larger divergences 500 years between sofular and hulu are only observed for gi 4 and 7 the sofular record differs from the most recent ngrip chronology by up to several centuries whereas age offsets do not increase systematically with depth the sofular record also reveals a rapid and sensitive climate and ecosystem response in the eastern mediterranean to gi whereas a phase lag of 100 years between climate and full ecosystem response is evident finally results of spectral analyses of the sofular isotope records do not support a 1 470 year pacing of gi

high resolution record of northern hemisphere climate extending into the last interglacial period high resolution record of northern hemisphere climate extending into the last interglacial period

age and geochemistry of tephra layers from ischia italy constraints from proximal distal correlations with lago grande di monticchio unraveling the eruptive history of the island of ischia southern italy is problematic due to its burial caldera collapse resurgent uplift and erosion here we present new major and trace element glass data for 39 75 ka proximal tephra deposits including those of the caldera forming monte epomeo green tuff megt eruption correlations with the distal tephra archive preserved at lago grande di monticchio lgdm are used to constrain the timing of as yet undated eruptive events out of 13 lgdm tephras analysed from the 39 104 ka time window glass geochemical data show that all are compositionally consistent with the explosive volcanic eruptions of ischia whilst 5 of them can be correlated with specific proximal deposits pre megt pyroclastic sequences comprise three compositional groups these groups occur repeatedly in sucessive eruptions proximal distal correlations indicate that the porticello eruption occurred at 59 2 ka and the tisichiello eruption probably occurred at 76 3 ka the megt eruption is correlated with lgdm tm 19 which has been directly dated at 55 2 ka post megt tephras form compositional groups that overlap with the pre megt but are displaced to lower feo and tio2 and lower incompatible element contents proximal distal correlations indicate that the schiappone and pietre rosse eruptions occurred at 50 6 2 0 ka and 45 6 ka respectively tephra from the megt eruption span a wide compositional range broadly overlapping the three pre megt compositional groups but are displaced to higher nd and y and contain an additional less evolved glass population glass geochemistry is used to recognise and confirm distal equivalents of the megt at lgdm tm 19 and in the ionian y 7 adriatic prad 1870 and tyrrhenian c 18 md 28 seas distal occurences of megt tephra define a dispersal axis to the south southeast and are found as far as 540 km from ischia making the megt one of the most widely dispersed late quaternary pyroclastic deposit erupted in the campanian region we estimate a volume of approximately 40 km3 for the fallout portion of the megt pyroclastic sequence on the basis of proximal and distal deposit thicknesses

tracing volcanic events in the ngrip ice core and synchronising north atlantic marine records during the last glacial period five basaltic tephra horizons have been identified in the ngrip ice core during the last glacial period geochemical analyses indicate that these tephras are of icelandic origin with one horizon identified as the faroe marine ash zone iii fmaz iii an important marker horizon in several marine records within the faroe islands margin the fmaz iii is a few millimetres thick and is constrained to 38 122 723 yr b2k before year ad 2000 according to the greenland ice core chronology gicc05 this event falls directly at the thermal peak of greenland interstadial 8 gi 8 and a marine ice correlation based on the position of this tephra suggests a close coupling of the marine and atmospheric systems at this time the remaining tephras originate from the eastern volcanic zone with the katla volcanic system pinpointed as the dominant source these are thought to represent previously unknown volcanic events which add considerably to our knowledge of icelandic volcanism during this period independent ages are assigned to these events and together with major element characterisation form the backbone of the tephrochronology framework presented here despite the identification of these tephras this study also demonstrates that the sulphate record may not always act as a suitable proxy for the identification of tephra horizons in ice core records

delimiting geochemical anomalies in the exploration of covered deposits with multifractal methods and using stream sediment data from the iberian pyrite belt southwest iberia abstract the iberian pyrite belt ipb is a world class province of upper paleozoic age for volcanic and shale hosted massive sulfides that includes 5 of the 10 supergiant 150 mt deposits of their kind in the world the volcano sedimentary sequences hosting the ores are locally exposed commonly covered by flysch type successions of variable thickness the baixo alentejo flysch group bafg as a result of primary sedimentary features and superimposed effects due to variscan folding and tectonic stacking in addition and when affected by late developed geomorphic depressions the exhumed paleozoic basement is also capped by meso cenozoic sediments the total thickness of cover sequences on top of the litho stratigraphic sequence of interest can reach 100 s of meters creating problems for mineral exploration a large stream sediment multi element geochemical database for the ipb was done in the 90 s during a wide ranging regional survey this database was reassessed by means of multifractal methods in view of their faculty to enhance the detection of faint geochemical anomalies and provide geochemical indicators to deep buried ore systems several anomalies were detected namely for cu zn and co along nw se to wnw ese trends the main anomalous geochemical trends identified include zones that i extend along the mira formation of bafg opening for the first time two non traditional areas for further exploration studies ii run along the boundary between the mira and mertola formations of bafg probably related to different geochemical signatures and late developed fault controlled epigenetic ore systems and iii overlap windows of volcanic sedimentary sequences within the cenozoic detrital cover and the site below which the deep buried deposit of lagoa salgada is located

mapping singularities with stream sediment geochemical data for prediction of undiscovered mineral deposits in gejiu yunnan province china abstract this paper proposes the concept of singularity for characterizing hydrothermal mineralization processes a singular physical process may result in anomalous amounts of energy release or material accumulation within a narrow spatial temporal interval mineralization can be considered as a type of singular process due to large amounts of material accumulation and element enrichment a spatial singularity mapping technique is developed based on the local singularity involved in the context of multifractal theory it assembles geochemical map at different scales and calculates an index indicating the scaling characteristics of enrichment and depletion of geochemical concentration at multiple scales this index was used for quantifying spatial singularity of mineralization associated geochemical anomalies a case study for the gejiu tin polymetallic mineral district yunnan province china demonstrates that the concepts of singularity and the singularity mapping technique are applicable and useful for delineating anomalies caused by mineralization and for predicting the locations of undiscovered mineral deposits

start and end of bedload transport in gravel bed streams 1 the threshold of incipient bedload motion expressed either as a critical force or as a critical water discharge is a key parameter in bedload transport prediction measuring the threshold of motion is difficult and reliable data from natural streams are rare by recording the vibrations triggered by bedload particles when moving over a steel plate mounted in the channel bed we determined the time at start and end of bedload transport in four streams where discharge is continuously monitored the threshold discharge scatters over approximately one order of magnitude for each stream reinforcing previous observations that critical discharge is characterized by a distribution of values we interpret a strong correlation between the discharge at the start of transport and the discharge at the end of transport of the previous event to reflect temporal changes in bed structure and consequent effects on the driving and resisting forces acting on the bed

evidence for nondiffusive transport of 86rn in the ground and a new physical model for the transport concentration of radon has been measured in the soil near the ground surface with solid state nuclear track detectors with the inverted cup technique measurements were made in the overburden at depth intervals 0 1 0 7 m at 0 1 6 m and at a constant depth of 0 2 m in a narrow rectangular matrix the results disagree with the hypothesis that radon concentration only depends upon local production and migration by diffusion with a diffusion length of about 1 m a transport length of 0 1 0 2 m is observed near the ground surface and the transport is dominated by a flow component radon measurements in the ground surface over the laisvall lead mine have given evidence of radon transport through rock exceeding a distance of 100 m which is possible only if the migration is a flow transport with a characteristic transport length larger than about 10 m day to explain the radon transport in the overburden and through the rock with a common transport system the existence of a general upward flow of geo gas is

a new greenland ice core chronology for the last glacial termination 1 we present a new common stratigraphic timescale for the north greenland ice core project ngrip and grip ice cores the timescale covers the period 7 9 14 8 kyr before present and includes the bolling allerod younger dryas and early holocene periods we use a combination of new and previously published data the most prominent being new high resolution continuous flow analysis cfa impurity records from the ngrip ice core several investigators have identified and counted annual layers using a multiparameter approach and the maximum counting error is estimated to be up to 2 in the holocene part and about 3 for the older parts these counting error estimates reflect the number of annual layers that were hard to interpret but not a possible bias in the set of rules used for annual layer identification as the grip and ngrip ice cores are not optimal for annual layer counting in the middle and late holocene the timescale is tied to a prominent volcanic event inside the 8 2 kyr cold event recently dated in the dye 3 ice core to 8236 years before a d 2000 b2k with a maximum counting error of 47 years the new timescale dates the younger dryas preboreal transition to 11 703 b2k which is 100 150 years older than according to the present grip and ngrip timescales the age of the transition matches the gisp2 timescale within a few years but viewed over the entire 7 9 14 8 kyr section there are significant differences between the new timescale and the gisp2 timescale the transition from the glacial into the bolling interstadial is dated to 14 692 b2k the presented timescale is a part of a new greenland ice core chronology common to the dye 3 grip and ngrip ice cores named the greenland ice core chronology 2005 gicc05 the annual layer thicknesses are observed to be log normally distributed with good approximation and compared to the early holocene the mean accumulation rates in the younger dryas and bolling periods are found to be 47 2 and 88 2 respectively

applying spatial prospectivity mapping to exploration targeting fundamental practical issues and suggested solutions for the future abstract despite many decades of development spatial prospectivity modelling is not yet widely used or accepted throughout the global mineral exploration industry a common criticism of the method is that it is not practically useful because it has a bias to mature well known areas and generates excessively large areas of high prospectivity it is suggested that the reason for this is not primarily related to limitations in the prospectivity mapping algorithms but rather to issues relating to the use of input data sets specifically it is common that the input data such as geological interpretations do not uniformly and objectively represent the search space of interest omit critical targeting relevant geoscientific elements such as major deep seated ore controlling structures and have a large degree of unrecognised dependence it is considered that these problems are not in principle barriers to the eventual successful deployment of this technology however future approaches to spatial prospectivity modelling need to explicitly address these concerns it is suggested that the most effective method may be a hybrid of subjective human geological interpretation and objective machine based analysis that captures the best aspects of these alternative approaches i e an intelligence amplification ia rather than an artificial intelligence ai approach a roadmap is proposed for improving the effectiveness of spatial prospectivity modelling that has implications for the broader community interested in mineral exploration targeting

influence of convective sedimentation on the formation of widespread tephra fall layers in the deep sea the formation of widespread volcanic ash fall layers in deep sea sediments was investigated experimentally to examine the settling behavior of tephra 20 180 m diameter as it travels from the atmosphere into water using a fallout mass flux rate that was constrained by measurements of distal fallout from the 1980 eruption of mount st helens 0 2 g cm 2 hr the experiments show that particle settling in the water column is dramatically accelerated by the formation of diffuse vertical gravity currents the currents form as a result of convective instabilities that develop in a surface boundary layer when the local particle concentration becomes large at the air water interface the settling velocity of particles drops abruptly and the concentration of particles increases because of the differential in mass flux above and below the fluid surface the implication of the experiments is that deposition of distal tephra fall layers in deep sea sediments may be dominantly controlled by diffuse vertical gravity currents as opposed to passive settling of individual particles through the water column this process greatly reduces the residence time of fine ash in the ocean and diminishes the role of ocean currents in influencing the distribution patterns of individual tephra layers support for this mechanism comes from observations of greatly accelerated tephra settling rates in the south china sea following the 1991 eruption of mount pinatubo in the philippines

mapping mineral prospectivity for cu polymetallic mineralization in southwest fujian province china abstract in this study both the fuzzy weights of evidence fwofe and random forest rf methods were applied to map the mineral prospectivity for cu polymetallic mineralization in southwestern fujian province which is an important cu polymetallic belt in china recent studies have revealed that the zijinshan porphyry epithermal cu deposit is associated with jurassic to cretaceous yanshanian intermediate to felsic intrusions and faulting tectonics evidence layers which are key indicators of the formation of zijinshan porphyry epithermal cu mineralization include 1 jurassic to cretaceous intermediate felsic intrusions 2 mineralization related geochemical anomalies 3 faults and 4 jurassic to cretaceous volcanic rocks these layers were determined using spatial analyses in support by geodas and arcgis based on geological geochemical and geophysical data the results demonstrated that most of the known cu occurrences are in areas linked to high probability values the target areas delineated by the fwofe occupy 10 of the study region and contain 60 of the total number of known cu occurrences in comparison with fwofe the resulting rf areas occupy 15 of the study area but contain 90 of the total number of known cu occurrences the normalized density value of 1 66 for rf is higher than the 1 15 value for fwofe indicating that rf performs better than fwofe receiver operating characteristics roc were used to validate the prospectivity model and check the effects of overfitting the area under the roc curve auc was greater than 0 5 indicating that both prospectivity maps are useful in cu polymetallic prospectivity mapping in southwestern fujian province

tephrostratigraphy study for the last 18 000 14 c years in a deep sea sediment sequence for the south adriatic abstract a detailed tephrostratigraphy supported by accelerator mass spectrometry ams 14c dating and isotopic and geochemical analyses has been carried out for a deep sea core collected from the southern adriatic sea which spans the last 18 14c kyr fourteen ash layers have been recognized in the marine core and the origin was determined by comparing their age and geochemistry with tephra detected in terrestrial deposits the geochemical signatures of marine ash layers indicate a prevailing campanian and subordinate etnean and eolian provenances collectively they are attributed to sources in the phlegraean fields lam lagno amendolare ln1 ln2 gm1 c 2 nyt neapolitan yellow tuff c 1 agnano pomici principali ams pf agnano monte spina ast astroni somma vesuvius l9 pomici di base l8 greenish mount etna et1 y1 biancavilla ignimbrite lipari e 1 gabellotto fiumebianco and palinuro seamount pal 1 some of these eruptions have been detected for the first time in marine cores astroni lam l9 l8 and three were detected and dated by marine tephra ln1 ln2 and pal 1 providing new more precise stratigraphic markers for the last 18 kyr in the south adriatic marine record

modelling ore forming processes through a cosine similarity measure improved targeting of porphyry copper deposits in the manzhouli belt china abstract recognizing distribution patterns of ore related pathfinder elements requires an understanding of the corresponding ore forming systems and may lead to the definition of more reliable exploration targets given that complex ore forming processes in complex geological terrains can result in either enrichment or depletion of ore elements simultaneous consideration of both processes in geochemical anomaly modelling would be advantageous for defining exploration targets here we adapted the cosine similarity measure method for pattern recognition of ore related geochemical anomalism to facilitate simultaneous modelling of element enrichment and depletion we tested the performance of this new method on porphyry copper exploration data from the manzhouli belt china and demonstrated that our method is highly efficient with respect to recognizing ore related geochemical signatures and thus useful for vectoring towards porphyry copper deposits and defining more reliable geochemical exploration targets

recognition of an enhanced multi element geochemical signature of porphyry copper deposits for vectoring into mineralized zones and delimiting exploration targets in jiroft area se iran abstract delimiting exploration targets using geochemical exploration data can be a challenging issue when different geochemical signatures represent the same deposit type sought in this regard fuzzy operators have been used to integrate different geochemical evidence layers into a single model for generating target areas in this paper a gis based expected value function was adapted to integrate different geochemical evidence layers into a stronger geochemical signature for delimiting exploration targets then the expected value function and fuzzy operators were compared the comparison demonstrated that the former is more efficient than the later for generating a stronger geochemical evidence layer the higher efficiency of the expected value function is because it simultaneously uses the value of all input variables and their relative importance in the process of integration the proposed approach was evaluated by using a lithogeochemical data set for prospecting porphyry cu deposits in jiroft area kerman province southeast of iran as a case study

abrupt temperature changes in the western mediterranean over the past 250 000 years a continuous high resolution western mediterranean sea surface temperature sst alkenone record spanning the past 250 000 years shows that abrupt changes were more common at warming than at cooling during marine isotope stage mis 6 sst oscillated following a stadial interstadial pattern but at lower intensities and rates of change than in the dansgaard oeschger events of mis 3 some of the most prominent events occurred over miss 5 and 7 after prolonged warm periods of high stability climate during the whole period was predominantly maintained in interglacial interstadial conditions whereas the duration of stadials was much shorter

tephrostratigraphy chronology and climatic events of the mediterranean basin during the holocene an overview the identification and characterisation of high frequency climatic changes during the holocene requires natural archives with precise and accurate chronological control which is usually difficult to achieve using only 14c chronologies the presence of time spaced tephra beds in quaternary mediterranean successions represents an additional independent tool for dating and correlating different sedimentary archives these tephra layers are potentially useful for resolving long standing issues in paleoclimatology and can help towards correlating terrestrial and marine paleoclimate archives known major tephras of regional extent derive from central and southern italy the hellenic arc and from anatolia a striking feature of major holocene tephra deposition events in the mediterranean is that they are clustered rather than randomly distributed in time several tephra layers occurred at the time of the s1 sapropel formation between c 8 4 and 9 0 ka bp mercato gabellotto fiumebianco e1 cappadocia and ot

correlation between volcanic and tectonic segmentation of fast spreading ridges evidence from volcanic structures and lava flow morphology on the east pacific rise at 9 10 n 1 combined analyses of volcanic features in dsl 120 sonar data and argo i images along the ridge crest of the east pacific rise 9 09 54 n reveal a consistent decrease in inferred lava effusion rate toward the ends of third order segments the correlation of tectonic segmentation and volcanic style suggests that third order segmentation corresponds to the volcanic segmentation of the ridge along axis changes in volcanic structures from collapse troughs to basaltic lava domes and lava morphology from sheet to pillow flows coincide with the boundaries of morphologically defined third order tectonic segments of the ridge crest visible in shipboard multibeam bathymetry pillow lava flows cover 25 of the surveyed area of the ridge crest and are closely associated with small lava domes that occur primarily at third order segment ends an additional 25 of the surveyed area of the ridge crest is covered by sheet lava flows found in close association with an axial collapse trough the remaining terrain consists of lobate lava flows we interpret the spatial correlations of morphologic structural seismic and petrologic data as evidence that individual volcanic plumbing systems are organized at 20 km spacing along the ridge axis third order segment scale in agreement with the hypothesis that volcanic and tectonic segmentations are correlated for fast spreading ridges we estimate that the longevity of volcanic segments is 104 105 years 1 3 orders of magnitude longer than fourth order segments 102 103 years this implies the present pattern of hydrothermal activity may reorganize tens or hundreds of times while volcanic segmentation remains fairly stable

a review of statistical chronology models for high resolution proxy based holocene palaeoenvironmental reconstruction abstract in this paper we explain the background workings and results obtained from three recently developed statistical age depth models implemented in freely available general purpose software packages bpeat oxcal and bchron these models aim to reconstruct the sedimentation rate in a single core typically lake peat or ocean given a limited number of scientific date estimates usually radiocarbon and fixed depths most importantly they provide a suitably qualified estimate of the uncertainty in the age depth chronology and thus can be used in a variety of applications we perform a large data driven study of the three models and discuss their general utility in chronology construction for palaeoenvironmental research

landscape geochemistry retrospect and prospect 1990 at present the terms environmental geochemistry and applied geochemistry are poorly defined in english in fact they usually mean just what a particular geochemist or geochemist s wishes them to mean there is a less common term landscape geochemistry which describes a holistic scientific discipline aimed at the geochemistry of the environment although little known outside the u s s r the basics of landscape geochemistry were first described more than 60 a ago since then landscape geochemistry has had a history pertinent to all scientists who participate in environmental geochemistry today this review traces the evolution of landscape geochemistry and related disciplines over the past 90 a and shows how they all relate to the development of modern environmental geochemistry worldwide in landscape geochemistry the term landscape refers to both the horizontal stratification of land e g into terrestial bog and aquatic ecosystems which co exist in an area of country and to the vertical stratification within these units e g into vegetation soils etc in these respects landscape geochemistry resembles landscape ecology which is currently a discipline of growing importance in environmental science landscape geochemistry differs from landscape ecology because it focuses attention on all aspects of the behaviour of chemical entities e g isotopes elements and ions in both living and dead matter in landscapes of all kinds from the viewpoint of general geochemistry landscape geochemistry focusess on the interaction of the lithosphere with the hydrosphere atmosphere and biosphere this holistic approach provides a common theoretical background for both pure and applied environmental geochemistry worldwide an important aspect of landscape geochemistry particularly pertinent to environmental geochemistry in the non soviet world today is that the subject provides a link between modern exploration geochemistry and modern environmental science including geochemistry historically landscape geochemistry stems from the russian school of landscape science this developed from the ideas of v v dokuchaev 1846 1903 around the turn of the century concepts unique to landscape geochemistry were first described in the 1920s by one of dokuchaev s students b b polynov 1867 1952 a i perel man 1909 a student of polynov began to teach landscape geochemistry at moscow university in 1952 since then the subject has become firmly established as the focus for fundamental and applied environmental geochemistry in the u s s r this review traces the development of landscape geochemistry from its origins around 1920 until 1990 the volume of literature pertinent to the review is voluminous for this reason attention is usually focused on the basic concepts and principles of landscape geochemistry and related scientific disciplines readers who require more detailed information on subjects covered in this review should consult the references cited the review is organized in four parts the first three trace the historical development of landscape geochemistry and related disciplines in three time periods these are 1 pre 1950 2 between 1950 and 1980 and 3 1980 1990 part 4 uses paradigms to summarize the historical evolution of landscape geochemistry and indicates how a global landscape geochemistry might develop in the future

exploration information systems a proposal for the future use of gis in mineral exploration targeting abstract the advent of modern data collection and storage technologies has brought about a huge increase in data volumes with both traditional and machine learning tools struggling to effectively handle manage and analyse the very large data quantities that are now available the mineral exploration industry is by no means immune to this big data issue exploration decision making has become much more complex in the wake of big data in particular with respect to questions about how to best manage and use the data to obtain information generate knowledge and gain insight one of the ways in which the mineral exploration industry works with big data is by using a geographic information system gis for example gis platforms are often used for integration interrogation and interpretation of diverse geoscience and mineral exploration data with the goal of refining and prioritising known and identifying new targets here we i briefly discuss the importance of carefully translating conceptual ore deposit models into effective exploration targeting maps ii propose and describe what we term exploration information systems eis a new idea for an information system designed to better integrate the conceptual mineral deposit model i e the critical and constituent processes of the targeted mineral system with data available to support exploration targeting and iii discuss how best to categorise mineral systems in an eis as scale dependent subsystems to form mineral deposits our vision for the future use of eis in exploration targeting is one whereby the mappable ingredients of a targeted mineral system are translated and combined into a set of weighted evidence or proxy maps automatically resulting in an auto generated mineral prospectivity map and a series of ranked exploration targets we do not envisage the eis replacing human input and ingenuity rather we envisage the eis as an additional tool in the exploration toolbox and as an intelligence amplifying system in which humans are making use of machines to achieve the best possible results

exploring for deeply covered mineral deposits formation of geochemical anomalies in northern chile by earthquake induced surface flooding of mineralized groundwaters northern chile is a major producer of copper from porphyry deposits most ores worked to date were exposed near the surface exploration is now focused on deposits along a basement unconformity buried under piedmont gravels deposited by ca 10 ma two recent discoveries the spence and gaby sur deposits are covered by gravel soils above these deposits have anomalies for elements present in saline mineralized groundwaters the anomalies occur above fracture zones in the gravels believed to represent the upward propagation of basement faults that guided emplacement of the porphyries we propose that during earthquakes in this seismically active region there was pumping of saline basement waters up the faults and fracture zones entraining mineralized groundwaters from the deposits after surface flooding and evaporation elements were redistributed by infrequent rains sampling shows that surface active cations such as cu 2 1 were adsorbed and retained in the top few centimeters of soil whereas nacl and porphyry indicator elements that dissolve as anions se re and as are not adsorbed and are removed to 40 cm depth given the 10 m y interval since the gravels were deposited and the hyperarid climate of the atacama desert anomalies may have formed by repeated episodes of seismically induced flooding company geochemical surveys show that such features are numerous in northern chile producing linear zones of saline soils plus other constituents of local groundwaters e g b and i where faults controlling these features intersect mineralization elements specific to the mineralization are also present saline zones may be outlined in the field by measuring the conductivity of soil plus water slurries sampling for full geochemical analyses can be limited to areas so defined anomalies may be generated along fault lines in other seismically active wetter climates but only for elements that are adsorbed on soil minerals although the context of the study is mineral exploration the process may be relevant to the formation of geochemical features of environmental interest above major faults

tracing time in the ocean a brief review of chronological constraints 60 8 kyr on north atlantic marine event based stratigraphies abstract well resolved event based stratigraphies in marine sediments spanning a significant portion of the last glacial period 60 8 kyr provide a unique opportunity for time stratigraphic correlation in the north atlantic region here we review the current methods available to chronologically constrain these event based stratigraphies highlighting in particular the value of tephrochronology as an independent tool to validate correlations between records while the intimate protocols lowe et al 2008 blockley et al 2011 are equally applicable to marine and terrestrial records spatially and temporally variable marine radiocarbon reservoir age effects mres provide a challenge to using marine radiocarbon in the former as an independent chronostratigraphic tool despite the inherent uncertainties associated with tuning we conclude that the mid points of the common abrupt warming transitions associated with the well defined millennial scale climate oscillations the dansgaard oeschger d o cycles observed in the oxygen isotopes of the greenland ice cores and north atlantic sea surface temperature sst records currently provide the most robust correlation tie points from which to derive age control in this invited intimate special issue article we propose a new protocol for establishing marine event based chronostratigraphies in the north atlantic region and focus on areas of chronological potential in palaeoceanographic research

variability of the western mediterranean sea surface temperature during the last 25 000 years and its connection with the northern hemisphere climatic changes sea surface temperature sst profiles over the last 25 kyr derived from alkenone measurements are studied in four cores from a w e latitudinal transect encompassing the gulf of cadiz atlantic ocean the alboran sea and the southern tyrrhenian sea western mediterranean the results document the sensitivity of the mediterranean region to the short climatic changes of the north atlantic ocean particularly those involving the latitudinal position of the polar front the amplitude of the sst oscillations increases toward the tyrrhenian sea indicating an amplification effect of the atlantic signal by the climatic regime of the mediterranean region all studied cores show a shorter cooling phase 700 years for the younger dryas yd than that observed in the north atlantic region 1200 years this time diachroneity is related to an intra yd climatic change documented in the european continent minor oscillations in the southward displacement of the north atlantic polar front may also have driven this early warming in the studied area during the holocene a regional diachroneity propagating west to east is observed for the sst maxima 11 5 10 2 kyr b p in the gulf of cadiz 10 9 kyr b p in the alboran sea and 8 9 8 4 kyr b p in the thyrrenian sea a general cooling trend from these sst maxima to present day is observed during this stage which is marked by short cooling oscillations with a periodicity of 730 40 years and its harmonics

spatial and temporal patterns in fluvial recovery following volcanic eruptions channel response to basin wide sediment loading at mount pinatubo philippines the june 1991 eruption of mount pinatubo philippines was one of the largest volcanic eruptions of the twentieth century emplacing 5 6 km 3 of pyroclastic fl ow material on the fl anks of the volcano the combination of abundant relatively fi ne grained easily erodible material and intense tropical rainfall led to numerous lahars immediately following the eruption even after major lahars ended sediment yields in some basins remained orders of magnitude above pre eruption levels using data collected from 1996 through 2003 we investigated fi ve basins that experienced varying amounts of sediment loading in the 1991 eruption from 1 to 33 of the basin area covered by valley fi lling pyroclasticfl ow deposits from measurements of fl ow and bed characteristics made through time we developed a general conceptual model for channel recovery following basin wide sediment loading initially fi ner grained sediment and pumice are mobilized preferentially through selective transport once the bed is coarse enough for gravel size clasts to interact with one another clast structures develop increasing form roughness and critical shear stress and inhibiting initial clast mobility as sediment inputs continue to decline the channel incises into valley bottom sediments progressively armoring through winnowing at pinatubo incision and armoring occur fi rst as dry season phenomena due to reduced sediment inputs eventually moving to year round low fl ow bed stability observed timing of the onset of in channel biological recovery suggests that reestablishment of channel stability helps catalyze aquatic ecosystem recovery

response to the comment by w h schwarz et al on joint determination of 40k decay constants and 40ar 40k for the fish canyon sanidine standard and improved accuracy for 40ar 39ar geochronology by p r renne et al 2010

a compilation of western european terrestrial records 60 8 ka bp towards an understanding of latitudinal climatic gradients terrestrial records of past climatic conditions such as lake sediments and speleothems provide data of great importance for understanding environmental changes however unlike marine and ice core records terrestrial palaeodata are often not available in databases or in a format that is easily accessible to the non specialist as a consequence many excellent terrestrial records are unknown to the broader palaeoclimate community and are not included in compilations comparisons or modelling exercises here we present a compilation of western european terrestrial palaeo records covering entirely or partially the 60 8 ka intimate time period the compilation contains 56 natural archives including lake records speleothems ice cores and terrestrial proxies in marine records the compilation is limited to include records of high temporal resolution and or records that provide climate proxies or quantitative reconstructions of environmental parameters such as temperature or precipitation and that are of relevance and interest to a broader community we briefly review the different types of terrestrial archives their respective proxies their interpretation and their application for palaeoclimatic reconstructions we also discuss the importance of independent chronologies and the issue of record synchronization the aim of this exercise is to provide the wider palaeo community with a consistent compilation of high quality terrestrial records to facilitate model data comparisons and to identify key areas of interest for future investigations we use the compilation to investigate western european latitudinal climate gradients during the deglacial period and despite of poorly constrained chronologies for the older records we summarize the main results obtained from nw and sw european terrestrial records before the lgm

a synchronized dating of three greenland ice cores throughout the holocene as part of the effort to create the new greenland ice core chronology 2005 gicc05 a synchronized stratigraphical timescale for the holocene parts of the dye 3 grip and ngrip ice cores is made by using volcanic reference horizons in electri cal conductivity measurements to match the cores the main annual layer counting is carried out on the most suited records only exploit ing that the three ice cores have been drilled at locations with different climatic con ditions and differences in ice flow however supplemental counting on data from all cores has been performed between each set of reference horizons in order to verify the valid ity of the match after the verification the main dating is transferred to all records us ing the volcanic reference horizons as tie points an assessment of the mean annual layer thickness in each core section confirms that the new synchronized dating is consistent for all three cores the data used for the main annual layer counting of the past 7900 years are the dye 3 grip and ngrip stable isotope records as the high accumulation rate at the dye 3 drill site makes the seasonal cycle in the dye 3 stable isotopes very resistant to firn diffusion an effort has been made to extend the dye 3 holocene record the new syn chronized dating relies heavily on this record of 75 000 stable isotope samples the dat ing of the early holocene consists of an already established part of gicc05 for grip and ngrip which has now been transferred to the dye 3 core gicc05 dates the younger dryas termination as defined from deuterium excess to 11 703 b2k 130 years earlier than the previous grip dating

consistent dating for antarctic and greenland ice cores we are hereby presenting a new dating method based on inverse techniques which aims at calculating consistent gas and ice chronologies for several ice cores the proposed method yields new dating scenarios simultaneously for several cores by making a compromise between the chronological information brought by glaciological modeling i e ice flow model firn densification model accumulation rate model and by gas and ice stratigraphic constraints this method enables us to gather widespread chronological information and to use regional or global markers i e methane volcanic sulfate beryllium 10 tephra layers etc to link the core chronologies stratigraphically confidence intervals of the new dating scenarios can be calculated thanks to the probabilistic formulation of the new method which takes into account both modeling and data uncertainties we apply this method simultaneously to one greenland ngrip and three antarctic epica dome c epica dronning maud land and vostok ices cores and refine existent chronologies our results show that consistent ice and gas chronologies can be derived for depth intervals that are well constrained by relevant glaciological data in particular we propose new and consistent dating of the last deglaciation for greenland and antarctic ice and gas records

evidence for general instability of past climate from a 250 kyr ice core record recent results1 2 from two ice cores drilled in central greenland have revealed large abrupt climate changes of at least regional extent during the late stages of the last glaciation suggesting that climate in the north atlantic region is able to reorganize itself rapidly perhaps even within a few decades here we present a detailed stable isotope record for the full length of the greenland ice core project summit ice core extending over the past 250 kyr according to a calculated timescale we find that climate instability was not confined to the last glaciation but appears also to have been marked during the last interglacial as explored more fully in a companion paper3 and during the previous saale holstein glacial cycle this is in contrast with the extreme stability of the holocene suggesting that recent climate stability may be the exception rather than the rule the last interglacial seems to have lasted longer than is implied by the deep sea specmap record4 in agreement with other land based observations5 6 we suggest that climate instability in the early part of the last interglacial may have delayed the melting of the saalean ice sheets in america and eurasia perhaps accounting for this discrepancy

the greenland ice core chronology 2005 15 42 ka part 1 constructing the time scale the greenland ice core chronology 2005 gicc05 is extended back to 42 ka b2k before 2000 ad i e to the end of greenland stadial 11 the chronology is based on independent multi parameter counting of annual layers using comprehensive high resolution measurements available from the north greenland ice core project ngrip these are measurements of visual stratigraphy conductivity of the solid ice electrolytical melt water conductivity and the concentration of na c a 2 s o 4 n o 3 n h 4 a n uncertainty estimate of the time scale is obtained from identification of uncertain annual layers which are counted as 0 570 5 years the sum of the uncertain annual layers the so called maximum counting error of the presented chronology ranges from 4 in the warm interstadial periods to 7 in the cold stadials the annual accumulation rates of the stadials and interstadials are on average one third and half of the present day values respectively and the onset of the greenland interstadials 2 3 and 8 based on 20 year averaged d 18 o

seismic signals of snow slurry lahars in motion 25 september 2007 mt ruapehu new zealand 1 detection of ground shaking forms the basis of many lahar warning systems seismic records of two lahar types at ruapehu new zealand in 2007 are used to examine their nature and internal dynamics upstream detection of a flow depends upon flow type and coupling with the ground 3 d characteristics of seismic signals can be used to distinguish the dominant rheology and gross physical composition water rich hyperconcentrated flows are turbulent common inter particle and particle substrate collisions engender higher energy in cross channel vibrations relative to channel parallel plug like snow slurry lahars show greater energy in channel parallel signals due to lateral deposition insulating channel margins and low turbulence direct comparison of flow size must account for flow rheology a water rich lahar will generate signals of greater amplitude than a similar sized snow slurry flow

offset timing of climate oscillations during the last two glacial interglacial transitions connected with large scale freshwater perturbation multidecadal to centennial planktic 18o and mg ca records were generated at ocean drilling program site 976 odp976 in the alboran sea the site is in the flow path of atlantic inflow waters entering the mediterranean and captured north atlantic signals through the surface inflow and the atmosphere the records reveal similar climatic oscillations during the last two glacial to interglacial transitions albeit with a different temporal pacing glacial termination 1 t1 was marked by heinrich event 1 h1 post h1 bolling allerod warming and younger dryas yd cooling during t2 the h11 18o anomaly was twice as high and lasted 30 longer than during h1 the post h11 warming marked the start of mis5e while the subsequent yd style cooling occurred during early mis5e the post h11 temperature increase at odp976 matched the sudden asian monsoon termination ii at 129 ka b p extending the 230th dated speleothem timescale to odp976 suggests glacial conditions in the northeast atlantic region were terminated abruptly and interglacial warmth was reached in less than a millennium the early mis5e cooling and freshening at odp976 coincided with similar changes at north atlantic sites suggesting this was a basin wide event by analogy with t1 we argue that this was a yd type event that was shifted into the early stages of the last interglacial period this scenario is consistent with evidence from northern north atlantic and nordic sea sites that the continuing disintegration of the large saalian stage mis6 ice sheet in eurasia delayed the advection of warm north atlantic waters and full strength convective overturn until later stages of mis5e

numerical modeling of landquakes the thurwieser landslide that occurred in italy in 2004 and the seismic waves it generated have been simulated and compared to the seismic signal recorded a few tens of kilometers from the landslide source i e landquake the main features of the low frequency seismic signal are reproduced by the simulation topography effects on the flowing mass have a major impact on the generated seismic signal whereas they weakly affect low frequency wave propagation simulation of the seismic signal makes it possible to discriminate between possible alternative scenarios for flow dynamics and to provide first estimates of the rheological parameters during the flow as landquakes are continuously recorded by seismic networks our results provide a new way to collect data on the dynamics and rheology of natural flows

geochemical challenges of diverse regolith covered terrains for mineral exploration in china abstract in recent years mineral exploration has concentrated on concealed deposits in regolith covered terrains in china the regolith covered landscapes mainly include desert windblown sand basins desert peneplains semi arid grassland loess plateaus forestry land alluvial plains and laterite terrains these diverse regolith covered areas represent geochemical challenges for mineral exploration in china this paper provides an overview of recent progress on mechanisms of metal dispersion from the buried ore deposits through the transported cover to the surface and penetrating geochemical methods to detect the anomalies case studies show that in arid and semi arid desert sand covered terrains sampling of fine fraction 120 mesh

seismic array constraints on reach scale bedload transport measurements and mechanical models of heterogeneous bedload transport in rivers remain basic challenges for studies of landscape evolution and watershed management a 700 m reach of the trinity river northern california usa a large gravel bed river was instrumented with an array of 76 seismographs during a dam controlled ood and gravel augmentation to investigate the potential for out of stream monitoring the temporal response to gravel augmentation during constant discharge provides strong evidence of seismic sensitivity to bedload transport and aids in identification of the seismic frequencies most sensitive to bedload in the study area following gravel augmentations the seismic array reveals a period of enhanced transport that spans most or all of the reach for 7 10 h neither the duration nor the downstream extent of enhanced transport would have been constrained without the seismic array sensitivity to along stream transport variations is further demonstrated by seismic amplitudes that decrease between the upper and lower halves of the reach consistent with decreased bedload ux constrained by time lapse bathymetry insight into the magnitude of impact energy that reaches the bed is also gained from the seismic array observed peak seismic power is 1 5 of that predicted by a model of saltation over exposed bedrock our results suggest that dissipation of impact energy due to cover effects needs to be considered to seismically constrain bedload transport rates and that noninvasive constraints from seismology can be used to test and refine mechanical models of bedload transport

defining element associations and inferring geological processes from total element concentrations in australian catchment outlet sediments multivariate analysis of continental scale geochemical data abstract in this paper the geochemical composition of surficial regolith is statistically analysed and compared to independent geoscientific datasets to infer processes governing regolith composition surface 0 10 cm depth and sub surface 60 80 cm depth transported sediment samples from the national geochemical survey of australia were analysed for total element content in both coarse censored data

volcanic ash reveals time transgressive abrupt climate change during the younger dryas knowledge of regional variations in response to abrupt climatic transitions is essential to understanding the climate system and anticipating future changes global climate models typically assume that major climatic changes occur synchronously over continental to hemispheric distances the last major reorganization of the ocean atmosphere system in the north atlantic realm took place during the younger dryas yd an 1100 yr cold period at the end of the last glaciation within this region several terrestrial records of the yd show at least two phases an initial cold phase followed by a second phase of climatic amelioration related to a resumption of north atlantic overturning we show that the onset of climatic amelioration during the yd cold period was locally abrupt but time transgressive across europe atmospheric proxy signals record the resumption of thermohaline circulation midway through the younger dryas occurring 100 yr before deposition of ash from the icelandic vedde eruption in a german varve lake record and 20 yr after the same isochron in western norway 1350 km farther north synchronization of two high resolution continental records using the vedde ash layer 12 140 40 varve yr b p allows us to trace the shifting of the polar front as a major control of regional climate amelioration during the yd in the north atlantic realm it is critical that future climate models are able to resolve such small spatial and chronological differences in order to properly encapsulate complex regional responses to global climate change

spectral analysis of seismic noise induced by rivers a new tool to monitor spatiotemporal changes in stream hydrodynamics to 20 db relative to m s 2 hz for all the stations located along a steep 30 km long narrow and deeply incised channel of the trisuli river a major trans himalayan river the early summer increase in high frequency energy is modulated by a 24 h periodicity where the minimum of seismic noise level is reached around noon and the maximum is reached late in the evening a detailed study of seismic noise amplitude reveals a clear correlation with both regional meteorological and hydrological data along the trisuli river seasonal increase in ambient noise coincides with the strong monsoon rainfall and a period of rapid melting of snow and ice in the high elevations the observed 24 h cyclicity is consistent with the daily fluctuation of the precipitation and river discharge in the region river induced seismic noise is partly generated by stream turbulence but this mechanism fails to explain the observed clockwise hysteresis of seismic noise amplitude versus water level this pattern is better explained if a significant part of the observed seismic noise is caused by ground vibrations generated by bed load transport this points out the potential of using background seismic noise to quantify in continuous river bed load and monitor its spatial variations which remain difficult with classical approaches

construction of a tephra based multi archive coherent chronological framework for the last deglaciation in the mediterranean region abstract proxy records from different climate archives such as ice cores speleothems or sediment cores are essential to define the sequence of events over to the last deglaciation however multi archive comparison and compilation of data necessary to assess the robustness of climate models are rapidly limited by inconsistencies between archives chronology here we present the development and validation of the datice chronological integration tool for the construction of multi archive coherent chronologies this chronology building tool first developed to date ice cores only can now integrate deposition like archives such as sediment cores and speleothems independently or coherently the robustness of this dating method resides in its capacity to build coherent chronologies for multiple archives with a proper calculation of chronological uncertainties using this tool we were able to construct a coherent chronology for the last deglaciation in the mediterranean region based on volcanic tephra layers correlation in terrestrial and marine sediment cores we confirm the synchronicity within chronological errors of the sequence of events characterizing the last deglaciation between greenland and the mediterranean region independently of any climatic alignment assumptions using this chronological framework we however highlight some regional expression of this transition period in term of vegetation cover over the mediterranean region

glass geochemistry of pyroclastic deposits from the aeolian islands in the last 50 ka a proximal database for tephrochronology abstract volcanic ash 1000 analyses provides a basis for proximal distal and distal distal tephra correlations tephra deposits from the different aeolian islands are geochemically diverse with some individual eruptions showing diagnostic geochemical heterogeneity recognised both stratigraphically and or spatially major element glass analyses reveal that vulcano 0 21 ka and stromboli 4 13 ka have erupted potassic shoshonitic and k series tephra with broadly overlapping compositions but data presented here demonstrates that their eruptive products can be distinguished using either tio2 contents or their hfse th ratios whilst individual volcanic sources often produce successive tephra deposits with near identical major and minor element compositions through time i e lipari vulcano trace element glass data can help to decipher successive eruptions changes in lree and th concentrations of volcanic glasses erupted spanning approximately the last 50 ka greatly enhance the potential to discriminate successive eruptive units on lipari the new proximal glass database has been used to verify new ionian sea core m25 4 12 and existing distal occurrences of aeolian island derived tephra enabling the reassessments of past ash dispersals finally proximal and distal data have been used to establish an integrated proximal distal eruptive event stratigraphy for the aeolian islands

precise dating of dansgaard oeschger climate oscillations in western europe from stalagmite data the signature of dansgaard oeschger events millennial scale abrupt climate oscillations during the last glacial period is well established in ice cores and marine records but the effects of such events in continental settings are not as clear and their absolute chronology is uncertain beyond the limit of 14 c dating and annual layer counting for marine records and ice cores respectively here we present carbon and oxygen isotope records from a stalagmite collected in southwest france which have been precisely dated using 234u 230th ratios we find rapid climate oscillations coincident with the established dansgaard oeschger events between 83 000 and 32 000 years ago in both isotope records the oxygen isotope signature is similar to a record from soreq cave israel and deep sea records indicating the large spatial scale of the climate oscillations the signal in the carbon isotopes gives evidence of drastic and rapid vegetation changes in western europe an important site in human cultural evolution we also find evidence for a long phase of extremely cold climate in southwest france between 61 2 0 6 and 67 4 0 9 kyr ago

the incidence and nature of bedload transport during flood flows in coarse grained alluvial channels a continuous record reveals that the incidence of bedload in a coarse grained river channel changes from flood to flood long periods of inactivity encourage the channel bed to consolidate sufficiently so that bedload is largely confined to the recession limb of the next flood wave but when floods follow each other closely the bed material is comparatively loose and offers less resistance to entrainment in this case substantial amounts of bedload are generated on the rising limb this is confirmed by values of bed shear stress or stream power at the threshold of initial motion which can be up to five times the overall mean in the case of isolated floods or those which are the first of the season this produces a complicated relationship between flow parameters and bedload and explains some of the difficulties in establishing bedload rating curves for coarse grained channels besides this the threshold of initial motion is shown to occur at levels of bed shear stress three times those at the thresholds of final motion this adds further confusion to attempts at developing predictive bedload equations and clearly indicates at least one reason why equations currently in use are unsatisfactory bedload is shown to be characterized by a series of pulses with a mean periodicity of 1 7 hours in the absence of migrating bedforms it is speculated that this well documented pattern reflects the passage of kinematic waves of particles in a slow moving traction carpet the general pattern of bedload including pulsations is shown to occur more or less synchronously at different points across the stream channel

application of geographically weighted regression to identify spatially non stationary relationships between fe mineralization and its controlling factors in eastern tianshan china abstract marine volcanic sedimentary fe mineral deposit is one of the most productive mineralization types in eastern tianshan mineral district uyghur autonomous region china previous researches have revealed that fe deposits in this area are mainly hosted by the lower carboniferous yamansu bimodal volcanic rocks and characterized by extensive skarn alteration due to variable effects of controlling factors across the study area fe mineralization occurs at limited locations with favorable geological environment in order to understand ore genesis of different fe deposits and to assist in fe mineral exploration in this area it is essential to investigate the spatial relationships between fe mineralization and its controlling factors across the study area in this paper fe mineralization and its controlling factors are characterized and delineated on the basis of spatial distributions of geochemical signatures obtained by principal component analysis the spatially non stationary relationships between these spatial distributions of geochemical signatures are further analyzed by a geographically weighted regression gwr method the comparison of applications of the ordinary regression and gwr shows that gwr is superior in depicting localized spatial relationships between fe mineralization and its controlling factors the gwr results demonstrate that influences of controlling factors on fe mineralization are spatially varied and imply that geological environments favorable to fe mineralization are diverse at different locations based on currently achieved results suggestions to support future fe mineral exploration at different subareas are proposed at the end of this paper