dynamic landscapes and human dispersal patterns tectonics coastlines and the reconstruction of human habitats studies of the impact of physical environment on human evolution usually focus on climate as the main external forcing agent of evolutionary and cultural change in this paper we focus on changes in the physical character of the landscape driven by geophysical processes as an equally potent factor most of the landscapes where finds of early human fossils and artefacts are concentrated are ones that have been subjected to high levels of geological instability either because of especially active tectonic processes associated with faulting and volcanic activity or because of proximity to coastlines subject to dramatic changes of geographical position and physical character by changes of relative sea level these processes can have both beneficial effects creating ecologically attractive conditions for human settlement and deleterious or disruptive ones creating barriers to movement disruption of ecological conditions or hazards to survival both positive and negative factors can have powerful selective effects on human behaviour and patterns of settlement and dispersal we consider both these aspects of the interaction develop a framework for the reconstruction and comparison of landscapes and landscape change at a variety of scales and illustrate this with selected examples drawn from africa and arabia

the formation of longitudinal fronts in a coastal plain estuary longitudinal estuarine fronts aligned parallel to the axis of the estuary are characteristic of the york river their time scale for genesis and decay is of the order of hours they are usually located at the inner edge of the shoals or over the main channel field measurements have shown marked intratidal differences in density and current speeds across this estuary these can be correlated with changes in depth and the strength of the advective processes differential advection between the channel and shoal regions when acting upon a constant longitudinal density gradient is shown to be of sufficient magnitude to generate strong lateral density gradients and thus fronts at particular times within the tidal cycle

coastal cliffs rock slope failures and late quaternary transgressions of the black sea along southern crimea abstract rock slope failures represent a significant hazard along global coastlines but their chronology remains poorly documented here we focus on the geomorphology and chronology of giant rockslides affecting the crimean mountains along the black sea coast geomorphic evidence suggests that high 100 m limestone cliffs flanking the southern slopes of the crimean mountains are scarps of rockslides nested within larger deep seated gravitational slope deformations dsgsds such pervasive slope failures originated due to lateral spreading of intensively faulted late jurassic carbonate blocks moving atop weak plastic late triassic flysch and tuff layers by introducing a dating strategy relying on the combination of the uranium thorium dating u th of exposed calcareous speleothems covering the landslide scarps with the 36cl exposure dating of rock walls we are able to approximate the time interval between the origin of incipient crevices and the final collapse of limestone blocks that exposed the cliff faces for the three representative large scale rockslides between the towns of foros and yalta the initiation of the dsgsds as evidenced by the widening of crevices and the onset of speleothem accumulation was 300 ka bp but the recent cliff morphology along the coast is the result of late pleistocene holocene failures spanning 20 0 5 ka bp the exposures of rockslide scarps occurred mostly at 20 15 8 5 4 and 2 0 5 ka which substantially coincide with the last major black sea transgressions and or more humid holocene intervals our study suggests that before ultimate fast and or catastrophic slope failures the relaxation of rock massifs correlative with karstification cracks opening and incipient sliding lasted on the order of 104 105 years rapid late glacial holocene transgressions of the black sea likely represented the last impulse for the collapse of limestone blocks and the origin of giant rockslides simultaneously affecting the majority of the sw coast of the crimean peninsula

major risk from rapid large volume landslides in europe eu project runout abstract project runout has investigated methods for reducing the risk from large volume landslides in europe especially those involving rapid rates of emplacement using field data from five test sites bad goisern and kofels in austria tessina and vajont in italy and the barranco de tirajana in gran canaria spain the studies have developed 1 techniques for applying geomorphological investigations and optical remote sensing to map landslides and their evolution 2 analytical numerical and cellular automata models for the emplacement of sturzstroms and debris flows 3 a brittle failure model for forecasting catastrophic slope failure 4 new strategies for integrating large area global positioning system gps arrays with local geodetic monitoring networks 5 methods for raising public awareness of landslide hazards and 6 geographic information system gis based databases for the test areas the results highlight the importance of multidisciplinary studies of landslide hazards combining subjects as diverse as geology and geomorphology remote sensing geodesy fluid dynamics and social profiling they have also identified key goals for an improved understanding of the physical processes that govern landslide collapse and runout as well as for designing strategies for raising public awareness of landslide hazards and for implementing appropriate land management policies for reducing landslide risk

on the nature of transverse variability in a coastal plain estuary even though estuarine processes are inherently three dimensional most of the previous studies have focused primarily on the axial longitudinal and vertical variabilities recent surveys in the lower delaware bay indicate the presence of significant transverse variability in the salinity distribution and residual circulation pattern conceptual models are developed to examine the mechanisms which might explain the observed transverse structure results indicate that both the gravitational effect and wind forcing are capable of generating substantial transverse structure in drowned river valley estuaries with triangular cross sections

start of the last interglacial period at 135 ka evidence from a high alpine speleothem a detailed study of growth periods of a flowstone from spannagel cave in the zillertal alps austria at 2500 m above sea level a site highly sensitive to climate changes offers unprecedented new insights into pleistocene climate change in central europe flowstone sample spa 52 has a high u content to 116 ppm analyses of this sample reveal that episodes of calcite deposition started at 204 3 ka 135 1 2 ka and 122 ka suggesting that at these times the mean air temperature at this high alpine site was within 1 5 c of the present day condition the beginning of growth at 135 ka corresponds to the ending of the last glaciation and is concordant with a midpoint age for the penultimate deglaciation at 135 2 5 ka as deduced from the absolutely dated oxygen isotope curve in sediments from the bahamas as well as with recent coral evidence from barbados indicating a high sea level already by 135 8 0 8 ka this set of data supports evidence against northern hemisphere forcing of termination ii because the insolation maximum is at 127 ka

climate and vegetation changes 180 000 to 345 000 years ago recorded in a deep sea core off portugal a new high resolution combined marine proxy pollen sequence from the portuguese margin md01 2443 enables direct comparison of ocean and ice volume changes with vegetation development in south west iberia during marine isotope stages mis 7 8 and 9 changes in sea surface conditions on both orbital and millennial time scales are closely mirrored by forest extent indicating a coherence of climate variability between the north atlantic and south west iberia deglacial warming at the start of mis 7 and 9 was interrupted by incursions of subpolar water masses at the site accompanied by reversals in tree population expansion during mis 7e and 9e the close relationship in timing and amplitude between vegetation and offshore conditions broke down early forest collapse points to pronounced cooling and aridification on land which although not accompanied by a change in water masses at the portuguese margin appears to have coincided with abrupt decreases in atmospheric methane concentration recorded in antarctic ice cores the most extreme glacial conditions of mis 8 occurred during the early part followed by an interval of warmer conditions and tree population expansion similar to 263 ka this has sometimes been considered as indicating an early deglaciation but the data presented here show that it was distinct from termination iii which occurred later in line with milankovitch forcing a sub orbital oscillation in both isotopic and pollen records is observed at the end of mis 7 ca 184 ka which appears to be coeval with a recently identified sea level high stand c 2006 elsevier b v all rights reserved

case history and hazard analysis of two lake damming landslides in the himalayas abstract in investigating the hazard and case history of natural dams in the himalayas two sites of landslides and their former dammed lakes in the hinterland were visited between may 1994 and october 1995 and analysed from the geomorphological geotechnical geohydrological tectonic sedimentary and climatic points of view one of the examples studied the landslide in the valley of birahi ganga northern india is one of the most impressive examples of recent hazards in alpinotype high mountain regions this study was complemented by a study of the ghatta khola landslide western nepal in both cases lithotectonic and climatic conditions led to the destabilisation and failure of carbonate bedrock the occurrence of lakes dammed over long periods behind the barriers is of great importance because after the sometimes fatal landslide event itself one is confronted and has to cope with a secondary natural hazard the possibility of a major flood due to the failure of the dam that is why the preparatory causal factors of the origin of the two lakes by damming up the river due to the landslide and their stepwise disappearance by secondary landslides within the barrier and sedimentation into the basin were additionally focused upon it is shown that due to very special circumstances availability of sediments heavy rainfall in the himalayas there is a progressive decrease in the potential hazard to the landscape and to human beings lower down the main valleys over a period of only a few decades

megarhizoliths in pleistocene aeolian deposits from gran canaria spain ichnological and palaeoenvironmental significance the pleistocene dune field of tufia located on the east of gran canaria spain contains different stratigraphic levels of indurated pillar like structures that are interpreted as megarhizoliths the megarhizoliths occur at the top of different aeolian sets and reach 31 5 cm in diameter and over 1 m in height these scattered free standing vertical cylindrical to slightly conical columns usually appear as hollow cylinders displaying elliptical cross sections aligned with the prevailing wind on the leeward side of some specimens the external wall shows a tail of rock matrix resembling a sort of wind shadow these tails and other remains of the associated rock matrix show a texture composed of long horizontal parallel cylinders orientated with the wind internally the most complete structures show five concentrically arranged zones zone a is a central pore corresponding to the cavity originally occupied by the root zones b and c which include alveolar and laminated carbonate textures indicating that carbonate precipitation was mostly induced by the roots and their associated microorganisms and zones d and e consisting mostly of aeolian sands in d the sand grains show thin micritic coatings whereas in e vadose aragonite cements can be seen on the grain surface suggesting a less biogenic influence in their formation the degree of cementation and the time of the precipitation of carbonate around the roots controlled the preservation of these zones thus in some cases zones b c and or d are not preserved cylinders are up to 30 the diameter of the root that nucleated them the presence of the megarhizoliths at the top of the aeolianite beds indicates that aeolian sedimentation halted several times allowing soil formation and plant colonisation during slightly more humid periods the occurrence of megarhizoliths is further proof of the alternation of arid and slightly more humid climates in the north atlantic during the last glacial period it is also noted that they may be misinterpreted as animal trace fossils or tree trunk casts resulting in incorrect ichnological or palaeoenvironmental interpretations

the last 1 35 million years at tenaghi philippon revised chronostratigraphy and long term vegetation trends abstract in addition to being of interest to ancient greek and roman historians the site of philippi ne greece has long been noted in quaternary circles for providing the longest continuous european pollen record spanning the last one million years here the original age model is re evaluated and a new marine terrestrial correlation is proposed an astronomical calibration procedure based on a correspondence between changes in certain vegetation elements and march and june perihelion configurations suggests that the base of the sequence extends back to 1 35 million years ago the revised chronological framework for the tenaghi philippon sequence provides an opportunity to examine the long term behaviour of individual taxa and vegetation trends within the context of global climate changes comparisons reveal a close correspondence between the terrestrial and marine records in terms of orbital and suborbital variability however joint time frequency analysis of the arboreal pollen record shows that the obliquity and eccentricity precession signals persist into the 100 kyr and 41 kyr worlds respectively suggesting the operation of additional climate mechanisms that are independent of high latitude glacial interglacial effects unlike ice core and marine sequences no change in the magnitude of interglacial tree population expansions is observed after the mid brunhes event instead the tenaghi philippon record suggests a major shift in the vegetational composition of interglacials after mis 16 with the establishment of forests of reduced diversity and a modern appearance

surface exposure dating of the flims landslide graubunden switzerland abstract sixteen boulder and bedrock surfaces related to the flims landslide volume 8 12 km3 were dated with 36cl and 10be exposure ages range from 4900 250 yr to 15 440 1480 yr including corrections made due to snow cover and karst erosion ages of 11 410 590 yr and 13 340 1090 yr were obtained on bedrock surfaces outside of the landslide zone these are minima for deglaciation of segnes valley and provide constraints on possible amounts of inherited nuclides based on seven boulder ages which range from 8200 260 to 9520 990 yr a mean of 8900 700 years is calculated for the flims landslide we exclude three outliers one significantly older and two significantly younger than the others and the ages from the cassons bedrock site from the mean calculation the latter is excluded as shielding due to snow and vegetation cover is difficult to constrain there the oldest boulder on the landslide yielded an age 15440 1480 yr more than 5000 years older than any other boulder age suggesting that it included the surface of the pre slide bedrock the exposure ages are consistent with a single failure event the erratics and patches of till lying on the landslide debris must have been carried piggy back on top of the landslide rather than having been deposited by the late pleistocene vorderrhein glacier the flims rockslide is about the same age as the kofels 9800 yr and kandertal 9600 yr rockslides all three occurred during the marked transition to warmer wetter conditions during the early holocene

biochronology of spanish quaternary small vertebrate faunas abstract thousands of fossils of small vertebrates are recorded in one of the most complete stratigraphic sequences of the continental european pleistocene in the sierra de atapuerca this sequence with a few interruptions spans the last 1 5 million years the stratigraphic series is recorded in six karstic cavities in the sierra de atapuerca from the oldest record to the most modern one these are the sima del elefante gran dolina galeria zarpazos sima de los huesos el portalon and el mirador the faunal successions of continental microvertebrates have made it possible to divide the atapuerca sequence into 7 faunal units atapuerca faunal units ata fus which are based on the first and last local appearances of taxa lo ho the spanish quaternary small vertebrate faunas are grouped into 5 distinct biozones from the oldest to the most recent allophaiomys pliocaenicus allophaiomys lavocati allophaiomys chalinei iberomys brecciensis and iberomys cabrerae these are calibrated with radiometric and palaeomagnetic dating allowing the proposal of a continental biochronological scale for the pleistocene of the iberian peninsula

beavers castoridae rodentia mammalia from the quaternary sites of the sierra de atapuerca in burgos spain abstract the eurasian beaver castor fiber is known from the pleistocene in europe although there are references to the presence of the genus castor since the miocene ca 10 ma beavers are present in the iberian peninsula since the pliocene though the first appearance of castor fiber took place in the early pleistocene levels of the localities of the sierra de atapuerca where the fossil beaver remains are found in the lower levels of sima del elefante and gran dolina early pleistocene galeria de las estatuas late pleistocene and portalon holocene the presence of fossil beavers suggests humid and mild climatic conditions in the early pleistocene levels of gran dolina and sima del elefante during the middle pleistocene although conditions for beavers seemed favourable they disappeared from atapuerca appearing again during the late pleistocene and the holocene

longitudinal transport in a coastal lagoon abstract a two dimensional finite difference numerical model is used to describe longitudinal transport through a transverse cross section into and out of the northern segment of indian river lagoon along the atlantic coast of florida the model uses four layers to represent the atlantic intracoastal waterway and two layers in the shallow waters east and west of the waterway to quantify transport simulations during a 161 day period from late june through late november 1983 include a seasonal shift in the longitudinal component of the wind transport is in the same sense throughout the cross section 32 of the time relatively subtle lateral shear however has a profound effect on long term net transport for most of the study cumulative net transport in the shallow areas on either side of the waterway follows the cumulative along channel windstress but it is directed upwind in the lower half of the intracoastal waterway four numerical experiments examine the relative importance of terms in the momentum equation and components of the database results suggest that time varying baroclinic forcing is an important component of the pressure gradient simulations which ignore water level variations at the open end of the model differ substantially from those which incorporate water level fluctuations

geographic and hydrodynamic characteristics of shallow coastal lagoons abstract coastal lagoons can be conveniently separated based on geomorphology into leaky restricted or choked systems this subdivision orders coastal lagoons hydrodynamically according to water exchange with the coastal ocean leaky systems have the shortest turnover time restricted lagoons have a longer turnover time and choked lagoons have the longest turnover time in leaky coastal lagoons oscillating tidal currents account for most of the flow variance and mask residual currents due to wind and freshwater induced density gradients in restricted lagoons tides winds and freshwater runoff drive components of the circulation winds are usually dominant in causing circulation and mixing in choked lagoons and water exchange with the coastal ocean largely depends on the hydrologic cycle coastal lagoons are usually well mixed but can exhibit significant horizontal gradients due to freshwater runoff and vertical gradients due to solar radiation or surface cooling in general river inflow and heat balance induce stratification in coastal lagoons whereas winds and tides cause mixing coastal lagoons usually trap inorganic sediment and organic matter thus serving as material sinks on a geologic time scale they are short lived landscape features with an existence intrinsically linked to filtering efficiency and relative sea level change as a result of glacioeustatic cycles and local tectonic activity

observations of wind induced subtidal variability in the delaware estuary sea level and current observations made in the delaware estuary during autumn of 1982 were examined for evidence of wind forced subtidal variability the large subtidal sea level fluctuations at the mouth of the delaware were found to be forced primarily by the wind stress component over the continental shelf nearly parallel to shore indicating coastal ekman transport to the right of the wind local wind forcing within the estuary is shown to be insignificant the subtidal sea level in the interior of the estuary was found to be driven by the wind through a combination of two remote forcing mechanisms one acting at the mouth of the delaware through direct estuary shelf coupling and a second acting locally over the chesapeake bay and being transmitted from the upper chesapeake through the chesapeake and delaware canal which links the two estuaries in the upper delaware estuary we found predominantly barotropic subtidal current fluctuations superimposed on a much weaker two layer gravitational circulation these current fluctuations were produced primarily by the local subtidal surface slope generated by the difference between the two remote forcing mechanisms the evidence strongly suggests that the chesapeake and delaware canal plays a critical role in the subtidal circulation of the delaware estuary

kinetic isotopic fractionation during carbonate dissolution in laboratory experiments implications for detection of microbial co2 signatures using δ13c dic laboratory experiments on reagent grade calcium carbonate and carbonate rich glacial sediments demonstrate previously unreported kinetic fractionation of carbon isotopes during the initial hydrolysis and early stages of carbonate dissolution driven by atmospheric co2 there is preferential dissolution of ca 12 co3 during hydrolysis resulting in 13 c dic values that are significantly lighter isotopically than the bulk carbonate the fractionation factor for this kinetic isotopic effect is defined as carb carb is greater on average for glacial sediments 17 4 than for calcium carbonate 7 8 for the 63 m size fraction a sediment concentration o f5gl 1 and closed system conditions at 5 c this difference is most likely due to the preferential dissolution of highly reactive ultra fine particles with damaged surfaces that are common in subglacial sediments the kinetic isotopic fractionation has a greater impact on 13 c dic at higher caco3 water ratios and is significant during at least the firs t6ho fcarbonate dissolution driven by atmospheric co2 at sediment concentrations o f5gl 1 atmospheric co2 dissolving into solution following carbonate hydrolysis does not exhibit any significant equilibrium isotopic fractionation for at least 6 h after the start of the experiment at 5 c this is considerably longer than previously reported in the literature thus kinetic fractionation processes will likely dominate the 13 c dic signal in natural environments where rock water contact times are short 6 24 h e g glacial systems headwaters in fluvial catchments and there is an excess of carbonate in the sediments it will be difficult apply conventional isotope mass balance techniques in these types of environment to identify microbial co2 signatures in dic from 13 c dic data copyright 2004

multiple dating approach 14c 230th u and 36cl of tsunami transported reef top boulders on bonaire leeward antilles current achievements and challenges abstract dating the transport deposition time of supratidal coarse clast deposits is difficult limiting their value for inferring frequency magnitude patterns of high energy wave events on bonaire leeward antilles caribbean these deposits form prominent landforms and transport by one or several holocene tsunamis is assumed at least for the largest clasts although a large dataset of 14c and electron spin resonance esr ages is available for major coral rubble ridges and ramparts it is still debated whether these data reflect the timing of major events and how these datasets are biased by the reworking of coral fragments as an attempt to overcome the current challenges for dating the dislocation of singular boulders three distinct dating methods are implemented and compared i 14c dating of boring bivalves attached to the boulders ii 230th u dating of post depositional secondary calcite flowstone and subaerial microbialites at the underside of the boulders and iii surface exposure dating of overturned boulders via 36cl concentration measurements in corals approaches ii and iii have never been applied to coastal boulder deposits so far the three 14c age estimates are older than 40 ka i e most probably beyond the applicability of the method which is attributed to post depositional diagenetic processes shedding doubt on the usefulness of this method in the local context the remarkably convergent 230th u ages all pointing to the late holocene period 1 0 1 6 ka are minimum ages for the transport event s the microbialite sample yields an age of 1 23 0 23 ka and both flowstone samples are in stratigraphic order the older onset of carbonate precipitation and younger flowstone layers yield ages of 1 59 0 03 and 1 23 0 03 ka respectively four coral samples collected from the topside of overturned boulders yielded similar 36cl concentration measurements however the computed ages are affected by large uncertainties mostly due to the high natural chlorine concentration after correction for the inherited component and chemical denudation since platform emergence inducing additional uncertainty the calculated 36cl ages cluster between 2 5 1 3 and 3 0 1 4 ka for three of four boulders whilst the fourth one yields an age of 6 1 1 8 ka probably related to a higher inheritance these 230th u and 36cl age estimates are coherent with a suggested tsunami age of

the lateral density distribution in a partially mixed estuary abstract the density distribution across the york river is characterized by distinct inhomogeneities especially in the upper 2 m of the water column the pattern of variability is repetitive and closely correlated with the semi diurnal tidal cycle and water depth in the shallow areas the water column remains vertically well mixed at all times the density differences are greatest at times of minimum currents at slack before flood the least dense water is located in a lens over the main channel towards the end of the flood cycle and at slack before ebb this is reversed with the least dense water situated over the shoals these density differences result in horizontal pressure gradients which at times may be of sufficient strength to generate localized lateral circulations such circulation patterns would form zones of convergence or divergence across the estuary depending on the particular density distribution

meteoric lithification of catastrophic rockslide deposits diagenesis and significance article deposits of catastrophic rockslides composed of lithologies rich in carbonate minerals may undergo precipitation of cements that can be used to proxy date the rockslide event and or subsequent geomorphic changes of the rockslide mass in the alps localized to widespread lithification of post glacial rockslide deposits is observed in lithologies ranging from limestones and dolostones to metacarbonates to calcphyllites lithification of rockslide deposits to breccias may be localized to meteoric runoff shadows below larger boulders or may comprise a layer of breccia or may affect a rockslide mass down its base in addition precipitation of cements and small stalactites may take place in megapores on boulder undersides cements found in rockslide deposits comprise skalenohedral calcite prismatic calcite blocky calcite calcitic micrite and micropeloidal calcitic cement and rarely botryoidal aragonite initial cement formation probably is driven by meteoric dissolution re precipitation of mini micritic abrasive rock powder generated by dynamic disintegration during the rockslide event preliminary

ungulate carrying capacity in pleistocene mediterranean ecosystems evidence from the atapuerca sites abstract large herbivore carrying capacity that is the maximum biomass of large herbivorous mammals that an ecosystem is able to sustain for the long term is a key factor in ecosystems trophic dynamics the carrying capacity of pleistocene ecosystems conditioned the survival opportunities and colonization capabilities of hominin populations in europe in this study we use the amphibian and squamate record of two early and middle pleistocene sites from sierra de atapuerca spain to obtain estimates of past temperature and rainfall values a function derived from the analysis of a wide set of recent mammalian communities is used to infer the large herbivore carrying capacity of the atapuerca ecosystems during the pleistocene from those climatic variables this function provides reliable estimates of large herbivore carrying capacity in open environments but not in forest communities the results presented in this study indicate that carrying capacity was higher at atapuerca during most of the sequence than in the present our data also suggest that in most mediterranean ecosystems large herbivore biomass is currently below the carrying capacity of the environment due to the relatively low diversity of the large herbivore guild in most recent communities although the carrying capacity was high at atapuerca in the periods the area was occupied by humans it was also high in other periods for which no evidence of human presence has been recorded thus the relationship between human occupation of the territory and carrying capacity does not appear to be simple

a simple model of estuarine subtidal fluctuations forced by local and remote wind stress observations of estuarine low subtidal sea level and current fluctuations have often shown domination by the remote effects of the wind acting on the adjacent coastal ocean over the local surface stress acting on the estuary itself the remote effects are transmitted to the estuary by impressment on its mouth of sea level change indtlced by the onshore component of coastal ekman transport and become increasingly dominant as the frequency decreases a simple barotropic model is developed to investigate the joint action of these two wind forcing mechanisms the relative shortness of most estuaries relative to low subtidal estuarine wavelengths explains the dominance of the remote effect for both sea level and barotropic current fluctuations in the estuary for the same reason however surface slope is dominated by local wind setup for an estuary with axis nearly parallel to the coast the two effects will operate either in concert or in opposition depending on hemisphere and orientation of the estuary axis relative to the coast for the geometries of both chesapeake bay and the delawm e estuary the model predicts opposition with the remote effect dominant at lower frequencies consistent with recent observations

terrestrial stromatolites and laminar calcretes a review abstract laminated carbonates are prominent features of subaerial exposure profiles and many types of calcareous soils including calcretes previously much attention was given to differentiating these laminites from marine or lacustrine microbial stromatolites and oncoids however recent research has shown that many subaerial laminated carbonates are biogenically formed mainly but not wholly by microbial activity this paper reviews the criteria for distinguishing terrestrial carbonate laminites from non terrestrial stromatolites and oncoids and for differentiating biogenic from abiogenic terrestrial laminites

multi method 14c 36cl 234u 230th age bracketing of the tschirgant rock avalanche eastern alps implications for absolute dating of catastrophic mass wasting correct and precise age determination of prehistorical catastrophic rock slope failures prerequisites any hypotheses relating this type of mass wasting to past climatic regimes or palaeo seismic records despite good exposure easy accessibility and a long tradition of absolute dating the age of the 230 million m3 carbonate lithic tschirgant rock avalanche event of the eastern alps austria still is relatively poorly constrained we herein review the age of mass wasting based on a total of seventeen absolute ages produced with three different methods 14c 36cl 234u 230th 36cl cosmogenic surface exposure dating of five boulders of the rock avalanche deposit indicates a mean event age of 3 06 0 6 ka 234u 230th dating of soda straw stalactites formed in microcaves beneath boulders indicate mean precipitation ages of three individual soda straws at 3 20 0 26 ka 3 04 0 10 ka and 2 81 0 15 ka notwithstanding potential internal errors these ages provide an older than ante quam proxy for mass wasting this article is protected by copyright all rights reserved based on radiocarbon ages nine sites only it was previously suggested that the present rock avalanche deposit represents two successive failures 3 75 0 19 ka bp 3 15 0 19 ka bp there is however no evidence for two events neither in surface outcrops nor in lidar derived imagery and drill logs the temporal distribution of all absolute ages 14c 36cl 234u 230th also does not necessarily indicate two successive events but suggest that a single catastrophic mass wasting took place between 3 4 and 2 4 ka bp taking into account the maximum age boundary given by reinterpreted radiocarbon datings and the minimum u th ages of calcite precipitations within the rock avalanche deposits a most probable event age of 3 01 0 1 ka bp can be proposed our results underscore the difficulty to accurately date catastrophic rock slope failures but also the potential to increase the accuracy of age determination by combining methods this article is protected by copyright all rights reserved

new palaeoenvironmental and palaeoclimatic reconstructions for the middle palaeolithic site of cuesta de la bajada teruel eastern spain inferred from the amphibian and squamate reptile assemblages abstract in the eastern iberian peninsula the archaeological site of cuesta de la bajada teruel spain has produced some of the earliest evidence of middle paleolithic stone tool traditions together with evidence of equid and cervid carcasses defleshed by hominins based on the numerical age of 317 240 ka derived from osl esr and aar dating methods for the lower part of the cuesta de la bajada sedimentological sequence level cb3 as well as the biochronological inferences for the small and large mammal associations the site can be attributed to marine isotope stage mis 8 or the end of mis 9 as amphibians and reptiles have precise environmental and climatic requirements and do not differ at species level from the extant herpetofauna of the iberian peninsula they can contribute to the reconstruction of the landscape and climate in this paper the fossil amphibians and squamate reptiles from cuesta de la bajada are studied for the first time the mutual ecogeographic range and habitat weighting methods were applied to the herpetofaunal assemblages to estimate quantitative data for the landscape and climate reconstructions the climate is shown to have been colder and wetter than today in the interior of eastern spain with mean annual temperature up to 2 5 c lower and mean annual precipitation slightly higher than at present the monthly climatic reconstruction shows differences in the distribution of precipitation over the course of the year with more abundant precipitation from late autumn to spring i e from october to may and more or less similar precipitation to today during the summer months july and august this suggests there was stronger rainfall seasonality between winter and summer than currently occurs the paleoenvironmental reconstruction based on the herpetofaunal assemblage depicts a poorly forested 15 20 patchy landscape with a large representation of dry meadows and scrubland habitats together with well evidenced aquatic habitats these reconstructions are consistent with other proxies recovered at cuesta de la bajada pollen small and large mammals as well as other european mis 8 9 paleoclimatic records we can thus correlate levels cb2 and cb3 with the later part of mis 8 265 257 ka or with a humid fluctuation within the mis9b 303 290 ka it is also possible to provide a new description of the environmental and climatic conditions that occurred in inner spain during a cold period of the late middle pleistocene

investigating the mid brunhes event in the spanish terrestrial sequence in the mediterranean area which is climatically stressed by limited water resources and extremes of heat climate variations are known to play a crucial role in the ecosystems and environment investigating how climate has changed in the past may help us to understand how it may change in the future and its consequences on temperature and water resources the gran dolina sequence north central spain provides a unique long paleontological and archaeological record spanning the mid brunhes ca 450 ka climatic transition a fossil amphibian and squamate based reconstruction of temperature and precipitation shows marked peaks that have been related to various interglacial peaks in accordance with numeric dates and paleomagnetic and biochronological data an analysis of climate and herpetofaunal assemblage changes during the interglacial periods reveals that 1 post mid brunhes event mbe interglacials were warmer than pre mbe interglacials 2 pre mbe interglacials were warmer than present day and 3 there were lower levels of rainfall in post mbe interglacials than in pre mbe interglacials the climate trend in the mediterranean area was found to be congruous with global climate changes as reconstructed from ice and sea surface temperature records over the past million years

insights into rock avalanche emplacement processes from detailed morpho lithological studies of the tschirgant deposit tyrol austria large rapid rockslope failures generate deposits with complex morphologies due to a number of causal and influencing factors to investigate these we conducted a detailed case study at the carbonate tschirgant deposit tyrol austria it preserved evidence of simultaneous rock sliding very large coherent hummocks and rock avalanche spreading smaller more scattered hummocks and ridges motion indicators such as longitudinal ridges furthermore pinpoint the transition between linear sliding and radial spreading the lithological distribution in the tschirgant deposit shows that it retained source stratigraphy despite being split into two accumulation lobes by a high bedrock ridge furthermore lithology had a very strong control on the final deposit morphology in that the different lithologic units form individual deposit surfaces river erosion has created fortuitous outcrops that reveal the basal rock avalanche contact the underlying valley fill sediments substrates have been intricately involved in shaping the rock avalanche morphology and where entrained highlight internal rock avalanche deformation features this study shows that intrinsic dynamic properties of granular media e g tendency for longitudinal alignments emplacement mode lithology and source predisposition runout path topography and substrates form the quintet of causal factors that shape rock avalanche morphology copyright 2015 john wiley sons ltd

early pleistocene palaeoenvironments at the time of the homo antecessor settlement in the gran dolina cave atapuerca spain hominin remains unearthed from level td6 2 of gran dolina have been dated to slightly more than 0 8 ma owing to the importance of this discovery every effort is being made to reconstruct the environment where these hominins once lived in this paper the mutual climatic range and habitat weighting methods are applied to the herpetofaunal assemblages in order to estimate climatic and environmental parameters td6 2 is thus characterized by a warm and humid climate mean annual temperature is estimated at 2 1 c higher than at present in burgos with a greater increase in temperature during summer 3 1 c than during winter 1 4 c rainfall was more abundant than at present 407 2 mm occurring as at present principally during spring and autumn humid meadows and riparian woody habitats were common the association between warm climatic conditions and the not fully developed forest suggests that the several episodes of high intensity occupation in td6 2 may correspond to a recolonization by homo antecessor of the high inland plateaus of the iberian peninsula from the mediterranean seashore using the ebro valley as a savannah type corridor after a cold glacial period copyright 2013 john wiley sons ltd

lake sediments deposited on the flims rockslide mass the key to date the largest mass movement of the alps long piston cores taken from the subsurface of two mountain lakes of the eastern swiss alps recovered sediments which overlie the flims rockslide deposits these sediments provide new information on the chronology of the largest known alpine rockslide and can be used to reconstruct the post landslide environmental evolution the oldest 14 c date of the lake sediments yields a minimum age of the rockslide at 9660 9430 cal yr bp in addition the dating of a wood fragment contained in the rockslide deposits directly below the lake sediments shows a maximum age of 9480 9120 cal yr bp the overlap of the maximum and minimum ages 9480 9430 cal yr bp approximates the age of the flims rockslide this early holocene range coincides with a period of higher frequency of large mass movements observed in the alps which could be related to climatic changes

a general model of paraglacial landscape response a unifying attribute of all forms of paraglacial response is that deglaciation results in the exposure of unstable or metastable sediment sources that are subsequently tapped by a wide variety of processes over a wide range of timescales the paraglacial period in different geomorphological contexts is therefore con ditioned by two variables glacially conditioned sediment release and rate of sediment reworking under steady state conditions the latter may be approximated by an exhaustion model in which sediment yield is related to the amount of remaining available sediment by a negative exponential function this model offers an approximation for the behaviour of primary paraglacial systems in which glacigenic sediment sources are not replenished the long term behaviour of secondary primarily uvial paraglacial systems in which sediment inputs include both in situ and reworked glacigenic sediment appears intrinsically more complex but consistent with an exhaustion model if initial sediment avai

pollen records from the middle pleistocene atapuerca site burgos spain abstract a pollen sequence resulting from a palynological analysis of sedimentary cave deposits at the atapuerca archaeological sites burgos spain is described the attribution of the sequence to the upper middle pleistocene is based on the fauna remains discovered and absolute dating of the stalagmitic crust covering the deposits a variation in the vegetation during the period covered by the pollen record is detected the essential forest components of the vegetation are deciduous and evergreen quercus together with a variable mosaic of accompanying species which indicate climates with a more temperate character in some cases and more mediterranean in others a hypothesis of chronological and climatic correlation is established for each of the pollen zones on the basis of vegetation fluctuations highlighted by the palynological analysis

geology and radiometric 14c 36cl and th u dating of the fernpass rockslide tyrol austria abstract one of the largest mass movements in the alps the fossil fernpass rockslide in the northern calcareous alps tyrol austria was dated absolutely for the first time three independent radiometric dating methods were applied to geologically individual sample sites and enabled a cross checking of the results close to the scarp front rockslide dammed torrent deposits indicate a 14c minimum age of at least 3380 3080 cal yrs bp the chronostratigraphic base of this backwater sequence has not been dated yet but is assumed to date somewhat older into the middle holocene however this coincides with two cosmogenic radionuclide 36cl ages of sliding planes at the steep and rugged scarp exposure data thus obtained are 3400 900 and 4800 1200 yrs respectively with an arithmetic mean of 4100 1300 yrs additional age data were acquired from post depositional calcareous cements which locally lithified the rockslide debris these meteoric cements contain remarkably high uranium total contents and yielded a 230th 234u minimum age of about 4150 100 yrs for the accumulation of the rockslide deposits all dating data agree well and indicate that the fernpass rockslide is of subboreal age thus the intensively structured present morphology characterised by the well known cone shaped toma hills and several lakes in the depressions is indicative of primary rockslide morphology and clearly not shaped by late glacial ice as assumed formerly

the continental record of marine isotope stage 11 middle pleistocene on the iberian peninsula characterized by herpetofaunal assemblages marine isotope stage mis 11 in iberia is documented at three main acheulean archaeological sites gran dolina burgos atapuerca aridos 1 madrid and ambrona soria as the amphibians and reptiles recovered as fossils from these sites are not extinct and their ecology can be directly studied mutual climatic range and habitat weighting methods have been applied to the herpetofaunal assemblages to estimate climatic and environmental parameters during mis 11 compared with today mean annual temperature varies from 2 7 to 0 3 c and mean annual precipitation varies from 311 7 to 74 4 mm suggesting in accordance with the numerical dates for each locality a progressive decrease in temperature and rainfall from the fully interglacial conditions of mis 11c to the end of mis 11 the presence of woodland areas is also well substantiated throughout the duration of mis 11 at least during the interglacial and interstadial periods

dynamic disintegration processes accompanying transport of the holocene flims sturzstrom swiss alps abstract a sturzstrom is a large scale landslide that evolves during transport into a rapid granular flow rock avalanche by a dynamic disintegration process numerous theoretical hypotheses have been proposed to explain the excessive mobility of these catastrophic mass movements but the role of disintegration processes remains poorly understood exceptional outcrop conditions at the giant 12 km3 flims sturzstrom swiss alps permit the analysis of disintegration processes that result from shearing during transport in confined zones of the rock mass shearing is concentrated along preferred surfaces originating as bedding planes which evolve into shear band layers differential velocities of slabs separated by these shear layers induce oblique fractures in the slabs by accommodation contacts between grains are maintained in the shear layers in unconfined zones near the top and the lateral margins shearing generates dilatancy the rock mass is affected by anisotropic dispersion without mixing and disintegrated material is preferentially produced to the top due to inflation the rock slide then evolves to a granular flow the consequence of these processes is the formation of two distinct depositional facies in the sturzstrom the structured facies exhibits a stratified aspect close to the base reflecting confined slab on slab shearing motion towards the top and distally it evolves into a chaotic facies with some isolated pockets of the structured facies reduction of confining forces on the moving sturzstrom allows transformation of the structured facies into the chaotic facies this characteristic transition observable in many sturzstrom deposits seems to be necessary for the rock avalanche process to occur and offers insights into the long runout characteristics of these catastrophic mass movements

the early middle pleistocene palaeoenvironmental change based on the squamate reptile and amphibian proxies at the gran dolina site atapuerca spain abstract although still ongoing the archaeological and palaeontological excavations in the gran dolina cave sierra de atapuerca burgos every year since 1976 have already revealed a long culturally and palaeontologically rich sequence dated by biostratigraphy esr u series and the palaeomagnetic record at between roughly 1 my and 250 ky gran dolina has one of the longest and most continuous vertical profiles the section 19 m thick divided into 11 stratigraphic levels represents a time span of nearly 700 000 years the gran dolina sequence was partially excavated during a preliminary evaluation of its archaeological and palaeontological richness this excavation known as the gran dolina sondeo south lasted from 1993 to 1999 hominin remains were unearthed in 1994 from level 6 of gran dolina and level 6 was dated to somewhat more than 780 ky based on palaeomagnetic and microfaunal evidence making these the oldest known hominins in europe given the importance of this discovery every effort is being made to reconstruct the landscapes where these hominins once thrived the gran dolina sondeo south tds has furnished a great number of microvertebrate remains and of these around 40 000 bones are attributed to amphibians and squamates the faunal list of the squamates and amphibians of the tds comprises at least 22 species a diversity similar to what exists nowadays in spain triturus sp alytes obstetricans pelobates cultripes pelodytes punctatus bufo bufo bufo calamita hyla arborea rana temporaria rana cf dalmatina rana cf iberica pelophylax ridibunda sp blanus cinereus lacerta s l small sized indeterminate lacertids anguis fragilis natrix natrix natrix maura coronella austriaca coronella cf girondica rhinechis scalaris vipera cf aspis and vipera cf latasti these ectotherm vertebrates show variations in their taxonomic diversity throughout the sequence although they do not differ specifically from the extant herpetofauna of the iberian peninsula they do so in the composition of their taxonomic assemblage when the squamates and amphibians of tds are grouped by habitat categories the habitat weightings method and studied in terms of their vertical evolution throughout the sequence it is possible to follow environmental changes across the early middle pleistocene transition results from the squamate and amphibian studies indicate that the landscape had open habitats in the vicinity of the atapuerca caves throughout the sequence with wet points in the surrounding area open dry microhabitats were more developed during warm periods whereas during cold periods the environment was slightly more humid and wooded these results are compared with studies in small mammals pollen analysis and geomorphology giving a scenario for the palaeoclimatic and palaeoenvironmental changes that occurred during the early to middle pleistocene boundary in atapuerca and hence a scenario for the hominins that once lived in the sierra de atapuerca

towards a middle pleistocene terrestrial climate reconstruction based on herpetofaunal assemblages from the iberian peninsula state of the art and perspectives abstract the pattern of the varying climatic conditions in southern europe over the last million years is well known from isotope studies on deep ocean sediment cores and the long pollen records that have been produced for lacustrine and marine sedimentary sequences from greece italy and the iberian margin however although relative glacial and interglacial intensities are well studied there are still few proxies that permit quantitative terrestrial temperature and precipitation reconstruction in this context fauna based climate reconstructions based on evidence preserved in archaeological or palaeontological sites are of great interest even if they only document short windows of that climate variability because a they provide a range of temperature and precipitation estimates that are understandable in comparison with present climate b they may allow the testing of predicted temperature changes under scenarios of future climate change and c quantitative temperature and precipitation estimates for past glacials and interglacials for specific regions latitudes can help to understand their effects on flora fauna and hominids as they are directly associated with those cultural and or biological events moreover such reconstructions can bring further arguments to the discussion about important climatic events like the mid bruhnes event a climatic transition between moderate warmths and greater warmths during interglacials in this paper we review a decade of amphibian and reptile based climate reconstructions carried out for the iberian peninsula using the mutual ecogeographic range method in order to present a regional synthesis from mis 22 to mis 6 discuss the climate pattern in relation to the mid bruhnes event and the thermal amplitude suggested by these estimates and finally to identify the chronological gaps that have still to be investigated

chemical weathering in the foreland of a retreating glacier chemical denudation rates and strontium isotope ratios in streams vary substantially and systematically in the foreland of the retreating bench glacier in south central alaska to study weathering of young glacier sediments we sampled 12 streams draining a chronosequence of till and moraine soils derived from cretaceous metagraywacke metapelite bedrock both sediment age and vegetation cover increase with distance from the glacier cation denudation rates decline with increasing distance from the glacier whereas silica denudation rates increase carbonate dissolution and sulfide oxidation account for roughly 90 of the solute flux from the youngest sediments biotite alteration accounts for 5 11 of the solute flux its peak contribution is found in the glacier outlet stream silicate weathering is the dominant reaction only in the oldest sediments in a laboratory dissolution experiment using fresh glacial sediment carbonate dissolution dominated the solute flux during the first 700 hours paralleling the behavior of young sediments in the field in contrast to trends in the field the silica flux did not increase after the carbonate was exhausted from the reactor a possible reason for this difference is that establishment of vegetation causes an increase in silicate weathering the 87sr 86sr ratio in the glacier outlet stream is greater than that in proglacial streams and in bulk rock due to a greater contribution of biotite weathering in the outlet than in proglacial streams strontium isotope ratios decline with sediment exposure age in the proglacial streams and are consistent with a carbonate source because the dominant weathering reactions in the young sediments are of carbonate and sulfide rather than silicate minerals weathering at the glacier margin is not an important long term sink for atmospheric co2

one million years of cultural evolution in a stable environment at atapuerca burgos spain abstract the present paper analyses the evidence provided by three sites sima del elefante gran dolina and galeria located in the trinchera del ferrocarril of the sierra de atapuerca these three sites are cave infillings that contain sediments deposited from approximately 1 2 ma to 200 kyr pollen herpetofauna and small and large mammal remains are used as proxies to obtain a general picture of the environmental changes that occurred at the sierra de atapuerca throughout the one million year period represented at these sites similarly cultural changes are tracked analyzing the evidence of human behavior obtained from the study of several bone and lithic assemblages from these three sites at least three periods with different cultural features involving technology subsistence and behavior are determined from the available evidence the first two periods correspond to the mode 1 technology and homo antecessor the first is dated around 1 2 to 1 0 ma and reflects opportunistic behavior both in technology and subsistence the second period is around 800 kyr bp mode 1 technology is still maintained but subsistence strategies include systematic hunting and the use of base camps the third period is dated between 500 ka and 200 ka and corresponds to the mode 2 technology and the acquisition of directional hunting and other organizational strategies by homo heidelbergensis a transition from mode 2 to mode 3 seems to appear at the end of this time range and may reflect the early phases of a fourth cultural change with regard to the environment our main conclusion is that there was an absence of extremely harsh conditions at atapuerca throughout this time period the presence of mediterranean taxa was constant and the dominant landscape was a savannah like open environment probably with small forest patches an alternation of mediterranean and mesic species as the dominant component of the tree storey was induced by the climatic cycles and steppes spread across the landscape during the drier periods in any case it is not possible to establish clear cut off points separating entirely different environmental episodes our results show no evidence of any relationship between environmental change and cultural change at the sierra de atapuerca

paleosols in shallow marine carbonate sequences abstract shallow water carbonate sequences in the geological record commonly exhibit numerous exposure surfaces reflecting emersion of sediment due to progradation processes and sealevel oscillations some ancient platform sequences contain hundreds of such surfaces associated with paleosols fossil soils typically calcretes a wide range of macro and microstructures are associated with these calcretes which are reviewed profile types and stages in profile development can be defined the nature of the exposure surface and associated paleosols can be used to identify the nature of the prevailing climate although hydromorphic effects related to marine flooding of the platforms can modify the paleosols a potentially important use of paleosols is to define the nature of sequence boundaries several studies have identified sets of paleosols with varying maturities reflecting changes in rates of accommodation space creation during sealevel rises and falls

the benner pass rock avalanche cluster suggests a close relation between long term slope deformation dsgsds and translational rock slides and catastrophic failure abstract in mountain ranges deep seated gravitational slope deformations dsgsds and extremely rapid mass wastings of rock 105 m3 in volume catastrophic rock slope failures crf are present yet their mutual relation is poorly documented near the brenner pass 1370 m asl in the eastern alps five catastrophic rock slope failures of medium to high grade metamorphites are clustered brenner pass cluster bpc and three of them are related to dsgsds the catastrophic rock slope failures involved volumes from 12 to 110 mm3 and show fahrboeschung angles of 10 27 numerical dating 14c 234u 230th suggests that all catastrophic slope failures of the bpc occurred between 13 5 and 6 2 ka three of the crf events may have occurred during the younger dryas 12 7 11 7 ka whereas two events occurred during the holocene backwater basins dammed up by the crfs range from 2 5 km2 ridnaun rock avalanche to 15 5 km2 stilfes rock avalanche three of the catastrophic rock slope failures are associated with and developed as a partial failure of a dsgsd this suggests that progressively slow deformation of slopes ultimately exceeded a stability threshold resulting in catastrophic rock slope failures the initial kinematic mechanisms of failure vary between large scale toppling wedge sliding and planar sliding and are strongly controlled by the structural setting of the slopes a direct connection of catastrophic mass wasting with specific palaeoclimatic conditions e g phases of enhanced precipitation is not indicated however this does not exclude specific meteorological situations e g occurrence of short term heavy rainfall that may have expedited slope instability and perhaps even triggered catastrophic events attempts to correlate catastrophic rock slope failures with specific palaeoclimatic regimes are still encumbered by substantial methodical uncertainties and imprecisions as well as the scarcity of dated crf events the mapped distribution of crfs unequivocally indicates that structural predisposition is the most significant long term control in forming crf clusters

alluvial deposits liquefied by the flims rock slide abstract the origin of the bonaduz gravel switzerland in the vicinity of the large holocene flims rock slide deposits has been discussed for a century the internal structure shows many features that imply transport as an over sized mud debris stream this flow of gravel sand and fines must have been triggered by the mobilisation of the valley alluvium by the impact of the rock slide the mobilised mud with a volume of several 100 million m 3 must have had enormous transport capacities as large units of loose material were transported over kilometres without breaking apart accordingly the shear forces in the flow must have been negligible similar features have been found at several other sites in the alps all in the vicinity of large rock slides our interpretation of these sediments as catastrophic mass movement deposits suggests that such events could happen again also in other parts of the world

the mutual climatic range technique is usually not the area of sympatry technique when reconstructing paleoenvironments based on faunal remains abstract names applied to particular analytical techniques must be explicit and distinctive the potential that two distinct techniques of paleoenvironmental reconstruction that use ancient faunal remains each with a particular name might be confused in the future has recently become a reality the name mutual climatic range mcr coined and developed in the 1980s and concerning the modern climatic not geographic co occurrence of species represented in a prehistoric collection of remains has been applied multiple times to a different technique first published in 2009 the new mcr technique is very similar to a distinct one developed in the 1950s and 1960s that focuses on the location of the geographic co occurrence of species in an assemblage relative to the location of the deposit producing the remains the older method has been known as the area of sympatry aos technique since 1966 histories of the aos and original mcr techniques suggest they were developed independently the new mcr technique seems to have been developed without knowledge of the two earlier ones to avoid future confusion of one technique with the other it is suggested that the new one be renamed the utm mcr technique because rather than use isopleths of climatic variables as the aos technique does it considers climatic variables within 10 10 km utm squares

landscape dissection isostatic uplift and the morphologic development of orogens we examine the morphologic factors that determine the isostatic response to landscape dissection in orogenic terrains in order to quantify the relative contributions of active tectonic uplift and passive isostatic uplift in generating mountain topography we demonstrate that although peaks many times the elevation of an assumed initial plateau can theoretically be generated only moderate amounts of peak uplift can be explained by isostatic rebound in real terrains analysis of topographic data from the european alps and other orogens indicates that isostatic uplift in response to dissection can account for about one fourth of the elevation of the highest peaks if local isostatic compensation is assumed and less if the lithosphere has significant flexural rigidity we conclude that although isostatic uplift can be significant in orogens high peaks are predominantly a consequence of tectonic processes in convergent settings

the subtidal circulation in delaware bay and adjacent shelf waters surface and seabed drifters were used to study the subtidal circulation in delaware bay and over the adjacent continental shelf of the middle atlantic bight over 7000 drifters were released in eight experiments during the year long study period velocity vector maps representing the study period mean fields for the surface and bottom confirmed the pattern of classical two layer estuarine flow with surface water moving seaward from the bay onto the shelf and bottom water landward over the shelf from at least as far as 40 km seaward of the bay mouth within the bay bottom water moved laterally toward the nearest shore diverging horizontally along a line roughly marking the deep channels the surface speeds were about an order of magnitude larger than the bottom significant variations from this mean pattern were seen between the eight experiments return percentages for surface and bottom drifters correlated inversely over the eight experiments correlations with wind stress were above the level of significance and winds explained about two thirds of the total variance the strong coupling found between the subtidal circulation in the estuary and over the shelf is consistent with recent observational and modelling studies

subtidal sea level and current variations in the northern reach of san francisco bay abstract analyses of sea level and current meter data using digital filters and a variety of statistical methods show a variety of phenomena related to non local coastal forcing and local tidal forcing in the northern reach of san francisco bay a partially mixed estuary low frequency variations in sea level are dominated by non local variations in coastal sea level and also show a smaller influence from tidally induced fortnightly sea level variations low frequency currents demonstrate a gravitational circulation which is modified by changes in tidal current speed over the spring neap tidal cycle transients in gravitational circulation induce internal oscillations with periods of two to four days

pleistocene amphibians and squamates from the upper jordan rift valley gesher benot ya aqov and nahal mahanayeem outlet mis 20 18 and mis 4 3

human occupation of iberia prior to the jaramillo magnetochron 1 07 myr abstract the first migration out of africa undertaken by the genus homo is documented in georgia at 1 8 myr dmanisi and some 0 4 myr afterwards in the middle east ubeidiya however the debate on when the european continent was populated for the first time remains open the first human presence in europe prior to the jaramillo subchron 1 07 0 99 myr is evidenced at fuente nueva 3 and barranco leon d orce and at sima del elefante atapuerca an occupation that seems to have continued through the jaramillo at gran dolina td3 4 and td5 atapuerca at vallparadis barcelona and up to the matuyama brunhes boundary at gran dolina td6 even so those who still defend a short chronology espouse an intermittent early population limited to the mediterranean area delaying the first occupation until after the jaramillo these hypotheses fail to explain what factors were behind the absence of population in europe prior to this period bearing in mind that there were populations of hominins at the gates of europe between 1 and 0 5 myr before the first archaeological record documented in western europe paleomagnetic analyses of the archaeological sites are rarely able to detect the jaramillo subchron due to its short duration while the radiometric dating methods u series esr usually applied are limited in the accuracy they can achieve for the chronologies in question these limitations make it necessary to depend on the biostratigraphy of small and large mammals to ascertain with precision the time of the first colonization of the continent accordingly in the present article we discuss the chronological data from the older iberian archaeological sites using biostratigraphic data to establish an archaeological sequence that demonstrates the expansion of the first hominin occupation of southern europe prior to jaramillo

filling in the gaps the contribution of non pollen palynomorphs to knowledge about the local environment of the sierra de atapuerca caves during the pleistocene abstract for several decades conventional pollen analyses have been supplemented with information provided by non pollen palynomorphs npp generally the taxa included in this group are microalgae fungi insects and arachnid s chitinous remains as well as plant debris and other organic palynomorphs of undetermined origin that are valuable tools with which to characterise the original strata as well as the local environmental features that influence deposit formation processes in this work we present the results of the npp analysis of the archaeological and palaeontological deposits of sima del elefante gran dolina and galeria all of which are located in the trinchera area sierra de atapuerca burgos spanning a period from 200 ka to almost 1 5 million years ago the npp analysis of the three deposits has provided information about the presence of decayed organic matter accumulations erosion processes and moisture conditions knowledge of palynomorphs contributes to the understanding of the biological physical and chemical dynamics that resulted in different sedimentary sequences in almost all cases there is a clear connection between the major stratigraphic trends established for the three deposits and the npp assemblages identified however the eminently local character of the dispersion of most of the palynomorphs identified has prevented the interrelation between the three sequences analysed