early stage sinkhole formation in the acque albule basin of central italy from geophysical and geochemical observations abstract sinkhole occurrence along the tyrrhenian margin of the central apennines is of great importance for applied research land management and civil protection this study reports on gps altimetry magnetic gravity geoelectric seismic and soil gas measurements of a rapidly developing sinkhole near the guidonia military airport the measurements revealed an elliptical 2 m depression elongated 220 m in the nne ssw direction with the minor axis of 110 m in the spring of 2013 two vertical cavities formed in the eastern and northeastern flanks of the depression whose depths and shapes are rapidly evolving with the formation of widespread fracturing along the same side the geophysical observations image the developing sinkhole to a depth of some 50 m the presence of the travertino lithotype around the depression down to at least 40 m and the lack of this lithotype below the lowered area the sinkhole s evolution appears to be structurally controlled by local and regional faulting these results are useful for designing further geophysical geotechnical and geochemical studies to monitor the sinkhole s evolution and to assess the hazard it presents in densely urbanized area

geochemistry of sediments of the ganges alluvial plains evidence of large scale sediment recycling the himalaya an amalgamation of different lithotectonic units brought together during and even before the himalayan orogeny has been subjected to various phases of denudation since the palaeogene sediments derived by erosion of these lithotectonic units in different proportions were delivered to the himalayan foreland the nature and proportions of sediments from various lithotectonic units delivered to the foreland varied in response to the prevailing tectonic and climatic conditions during the orogeny the geochemistry of sediments collected from floodplain river channels and reworked aeolian sediments from the delhi and moradabad areas of the ganges plain of the foreland basin indicates that they were derived from moderately weathered sedimentary sources further the results also suggest that the sediments are not subjected to any significant post depositional chemical weathering high tectonic instability in the source area and the geomorphology and cycles of aggradation and degradation in fluvial regimes in the ganges plain do not favor much chemical weathering homogenization of various lithotectonic units of the himalaya through several episodes of sedimentary reworking is shown by the rare earth elements ree geochemistry of the sediments the predominant source for the homogeneous sediments is likely the high himalayan crystalline or the tertiary sub himalayan sediments again the later was derived from high himalayan crystalline if so the ganges alluvial plain is geochemically a quaternary extension of tertiary sub himalaya the average composition of lithologies subjected to erosion in the himalaya appears to be better represented by the alluvial mud present in the plain

discovering research value in the campo del cielo argentina meteorite craters the campo del cielo meteorite crater field in argentina contains at least 20 small meteorite craters but a recent review of the field data and a remote sensing study suggest that there may be more the fall occurred 4000 years ago into a uniform loessy soil and the craters are well enough preserved so that some of their parameters of impact can be determined after excavation the craters were formed by multi ton fragments of a type ia meteoroid with abundant silicate inclusions relative to the horizontal the angle of infall was 9 reflecting the low angle of infall the crater field is elongated with apparent dimensions of 3 18 5 km the largest craters are near the center of this ellipse this suggests that when the parent meteoroid broke apart the resulting fragments diverged from the original trajectory in inverse relation to their masses and did not undergo size sorting due to atmospheric deceleration the major axis of the crater field as we know it extends along n63 e but the azimuths of infall determined by excavation of craters 9 and 10 are n83 5 e and n75 5 e respectively this suggests that the major axis of the crater field is not yet well determined the three or four largest craters appear to have been formed by impacts that disrupted the projectiles scattering fragments around the outsides of the craters and leaving no large masses within them these are relatively symmetrical in shape other craters are elongated features with multi ton masses preserved within them and no fragmentation products outside there are two ways in which field research on the campo del cielo crater field is found to be useful 1 studies exist that have been used to interpret impact craters on planetary surfaces other than the earth this occurrence of a swarm of projectiles impacting at known angles and similar velocities into a uniform target material provides an excellent field site at which to test the applicability of those studies 2 individual craters at campo del cielo can yield the masses of the projectiles that formed them and their velocities angles and azimuths of impact from these data there is a possibility to estimate parameters for the parent meteoroid at entry and thus learn enough about its orbit to judge whether or not it was compatible with an asteroidal origin preliminary indications are that it was campo del cielo is a ia iron meteorite and sikhote alin an observed fall is a iib iron meteorite in wasson s classification the sterlitamak iron also an observed fall is a medium octahedrite in the prior hey classification it would be interesting to compare their orbital parameters

geological and geochemical data from the proposed sirente crater field new age dating and evidence for heating of target the proposed sirente crater field consists of a slightly oblong main structure main crater 120 m in width and about 30 smaller structures satellite craters all in unconsolidated but stiff carbonate mud here we focus on the subsurface structure of the satellite craters and compare the sirente field with known meteorite crater fields we present a more complete outline of the crater field than previously reported information on the subsurface morphology of a satellite crater c8 8 m in width radiocarbon and thermoluminescence tl ages of material from this crater and evidence for heated material in both crater c8 and the rim of the main crater crater c8 has a funnel shape terminating downwards and evidence for soil injection from the surface to a depth of 9 m the infill contained dispersed charcoal and small irregular porous fragments of heated clay with a calibrated age of b p 1712 13c corrected radiocarbon age b p 1800 100 and a tl age of b p 1825 calculated error 274 together with previous radiocarbon age b p 1538 of the formation of the main crater i e target surface below rim a formation is suggested at the beginning of the first millennium a d although projectile vaporization is not expected in sirente sized craters in this type of target material we used geochemistry in an attempt to detect a meteoritic component the results gave no unequivocal evidence of meteoritic material nevertheless the outline of the crater field evidence of heated material within the craters and subsurface structure are comparable with known meteorite crater fields

investigations on buried soils and colluvial layers around bronze age burial mounds at bornhoved northern germany an approach to test the hypothesis of landscape openness by the incidence of colluviation the idea of open landscapes around prehistoric burial mounds is founded on their topographical position and findings of plaggen clots within the hills at some sites we have investigated the surroundings of four bronze age burial mounds at bornhoved northern germany to test whether this assumed landscape openness enabled soil erosion and colluviation or not the soils and colluvia within a watershed below the burial mounds were investigated in six large exposures and additional auger cores the chronology is based on 21 ams radiocarbon dates complemented by charcoal analysis and the content of selected heavy metals in the sediments colluvia were deposited in the late neolithic 2500 2200 cal bc roman emperor times 250 400 cal ad mediaeval times ad 600 1400 and modern times ad 1800 2000 our findings indicate that the soil surfaces were protected against soil erosion during the phase of bronze age funeral use cal 1800 600 bc either the prehistoric gravediggers practised a well suited form of pasturing to keep the scenery open or the surroundings of the burial mounds were forested at the time of funeral use the results of charcoal analysis reflect the known succession of woody taxa in the region and underline the great potential of anthracology on colluvial layers for palaeoenvironmental reconstructions apart from traditional archives such as lakes or mires bulk radiocarbon dating of organic matter overestimated the time of burial of a buried soil as well as the time of deposition of colluvial layers considerably

the sirente crater field italy we propose the sirente crater field to be the first discovered impact craters in italy they are located in the sirente plain within the mountains of the abruzzo region central italy the craters are distributed in a field 450 m long and 400 m wide this field consists of about 17 smaller craters close to a larger main crater the main crater is located in the southern end of the crater field and is 140 m long and 115 m wide measured rim to rim it has a well developed saddle shaped rim that rises at a maximum 2 2 m above the surrounding plain radiocarbon dating of the target surface preserved below the rim gave a calibrated age of formation at about 412 a d 1650 40 radiocarbon years b p this young age is consistent with the apparent little modification of the rim the morphology of the main crater and its relation to a crater field strongly points to its origin by impact from a projectile that broke up during its passage through the atmosphere quartz is very rare in the target and no planar deformation features pdfs have been found so far the rim material and the upper 4 m of the main crater infill are impregnated with ferric oxides which gives a more reddish colour compared to the other sediments of the plain rusty crusts with high fe and mn content occur in the rim material but have not been found in the plain s sediments some of these crusts can be separated by magnet and have sporadic micron sized ni rich granules the main crater is in the size range of craters with explosive dispersion of the projectile and has many features comparable to both large experimental and meteoritic impact craters formed in loose sediments we suggest that this crater represents a rare example of well preserved small impact craters formed in unconsolidated target materials

jurassic subsidence history in the hebrides n w scotland abstract geohistory analyses have been applied to the generally well dated triassic jurassic successions of three areas in the hebrides basin north west scotland and the importance of making corrections for decompaction palaeobathymetry and eustatic changes of sea level are assessed the thermo tectonic subsidence patterns in the skye areas north suggest a three phase history of crustal stretching though only the first phase is well developed in the mull area south episodes of relatively rapid subsidence are 1 1 late triassic c210 ma until earliest toarcian 186 ma 2 2 latest toarcian 180 ma until late bathonian c161 ma 3 3 early oxfordian 154 ma until at least early kimmeridgian incomplete these are separated by toarcian 186 180 ma and latest bathonian callovian c161 154 ma episodes of either little subsidence or of uplift but at slower rates than eustatic rise of sea level the intervals between phases at 30 ma and 26 ma are remarkably similar but the wider significance of this remains to be established

human impacts on fluvial systems in the mediterranean region the long history of substantial human impacts on the landscape of the mediterranean region and their effects on fluvial systems is documented these effects have included impacts of deforestation and other land use changes agricultural terracing on a wide scale water transfers and irrigation schemes during the 20th century major changes were made directly to channels through channelisation construction of dams of various sizes and extraction of gravel and indirectly by reforestation these changes have caused a major phase of incision on some rivers runoff and soil erosion have been affected by types of crops and agricultural practices as well as by the varying extent of cultivation and grazing some recent agricultural practices involve wholescale relandscaping of the topography and alteration of surface properties of material the importance of analysing the connectivity within different land units and of the spatial position of human activity within a catchment is illustrated the analysis of connectivity is the key to understanding the variability of impact and the extent of propagation of effects

human impact on land ocean sediment transfer by the world s rivers abstract land ocean transfer of sediment by rivers is a key pathway for material transfer on earth contemporary data on the sediment loads of rivers provide clear evidence of significant recent changes in the sediment fluxes of several rivers in response to human impact the key drivers of increased sediment loads include land clearance for agriculture and other facets of land surface disturbance including logging activity and mining although programmes for soil conservation and sediment control can result in reduced sediment loads the trapping of sediment by dams represents the dominant cause of reduced loads this influence is currently assuming increasing importance at the global scale any attempt to link these drivers to changes in the global land ocean sediment flux must take account of the aggregation and buffering effects that operate in larger basins which can cause damping and even removal of signals of increasing flux within the upstream basin and complicate the link between upstream and downstream response to human impact further work is required to provide a precise quantitative assessment of the human impact on global land ocean sediment fluxes and the net effect of increasing and decreasing fluxes particular attention must be paid to the temporal perspective and the variation of impact trajectories in different areas of the globe and for river basins of different sizes

imaging the structural style of an active normal fault through multidisciplinary geophysical investigation a case study from the mw 6 1 2009 l aquila earthquake region central italy firb abruzzo high resolution analyses for assessing the seismic hazard and risk of the areas affected by the 2009 april 6 earthquake no rbap10zc8k 005

sedimentary basin inversion caused by igneous underplating northwest european continental shelf a considerable body of evidence indicates that many of the extensional sedimentary basins in the vicinity of the british isles underwent permanent exhumation during the tertiary the most dramatic indicator of this process is the present day absence of as much as 4 km of anticipated postrift thermal subsidence in basins just north and west of scotland any explanation of this observation must take into account the fact that the entire region has very small long wavelength free air gravity anomalies this important constraint implies either that the crust has been thickened or that low density material has been added to or formed from the lithosphere and rules out models that invoke flexural effects arising from the opening of the north atlantic tertiary epeirogeny is often attributed to compression that is assumed to be related in a general sense to alpine mountain building however to remove 3 km of sedi mentary rock from a basin 100 km wide requires 15 km of shortening minor tertiary compression is observed all over the continental shelf but nowhere is it sufficient to account for the required amount of uplift and erosion in addition exhumation dramatically increases from south to north whereas the observed compression decreases markedly in the same direction at the beginning of the tertiary rifting associated with the initiation of the iceland plume generated substantial volumes of melt inversion of rare earth element concentrations of mgorich igneous rocks suggests that a minimum of 5 km of melt was produced beneath at least part of the continental shelf we infer that much of this melt remains trapped within the lithosphere presumably close to the moho which acted as a density filter such underplating will generate rapid uplift

are mid latitude slopes sensitive to climatic oscillations implications from an early holocene sequence of slope deposits and buried soils from eastern germany abstract on a straight slope within the lake catchment of kleiner tornowsee brandenburg germany a sequence of slope sediments has been deposited during the late glacial the early holocene and around cal 4 2 ka before today 800 500 and 300 years ago the chronology is based on 21 radiocarbon dates and 11 osl dates and a deposition model including the numerical data as well as stratigraphic information has been calculated with oxcal 4 1 a comparison of the woody taxa of charcoal particles n 566 embedded within the sediments with the known regional vegetation history confirmed the reliability of the dates according to the age volume and distribution the deposition of the early holocene sediments at ca 10 3 kyrs ca 9 5 kyrs and ca 8 2 to 7 7 kyrs before today strongly suggests an influence of known climatic deteriorations phases on geomorphologic processes cold and dry climatic conditions probably promoted wildfires in pinus dominated forests and therefore triggered the observed repeated slope instability in consequence mid latitude slope deposits provide a potential to reconstruct the geomorphological response to climatic events at a high spatial resolution in contrast the recorded mid to late holocene soil erosion phases on the slope have been triggered by land use activities apart from traditional environmental archives slope deposits provide valuable information about the vegetation and climate history

methane seeps and mud volcanoes in italy gas origin fractionation and emission to the atmosphere molecular composition ch 4 isotopes and gas flux of all main terrestrial mud volcanoes and other methane seeps in italy are being assessed for the first time whereas 74 of the italian gas reservoirs are biogenic about 80 of the seeps release thermogenic gas dry seep gas generally maintains the reservoir c 1 c 2 c 3 bernard ratio while mud volcanoes show molecular fractionation likely occurring during advective migration accordingly a simple and direct use of the bernard parameter might be misleading when applied to mud volcanoes as it could not always reflect the reservoir composition methane flux into the atmosphere from macro seep areas is in the order of 10 2 10 6 t km 2 y 1 microseepage is widespread throughout large areas and on a regional scale it provides the main methane output a first emission estimate for the total hydrocarbon prone area of italy suggests levels of 105 t y 1 comparable to national sources from fossil fuel industry

carbon dioxide earth degassing and seismogenesis in central and southern italy 1 we present the first regional map of co2 earth degassing from a large area most of central and south italy derived from the carbon of deep provenance dissolved in the main springs of the region the investigation shows that a globally significant amount of deeply derived co2 10 of the estimated global co2 emitted from subaerial volcanoes is released by two large areas located in western italy the anomalous flux of co2 suddenly disappears in the apennine in correspondence to a narrow band where most of seismicity concentrates here at depth the gas accumulates in crustal traps generating co2 overpressurized reservoirs which induce seismicity

jurassic sequence stratigraphy in the hebrides basin nw scotland abstract stratigraphical analysis of the triassic jurassic succession outcropping in the hebrides in terms of genetic sequences has identified seven major sequences and seven minor sequences the major sequence boundaries are defined at abrupt facies changes which usually represent deepening events often associated with a hiatus they are dated as 1 late triassic 2 mid sinemurian birchi subzone turneri zone diachronous to oxynotum zone 3 early toarcian exaratum subzone falciferum zone 4 latest toarcian aalensis subzone levesquei zone 5 late bajocian dichotoma subzone garantiana zone 6 late bathonian discus zone 7 early callovian medea subzone jason zone integrating stratigraphical with subsidence history analyses enables identification of basin tectonics as the causal mechanism for sequence boundaries 1 2 4 and 5 eustatic rises of sea level during toarcian and callovian phases of relative tectonic quiessence were the causes of sequence boundaries 3 6 and 7 late jurassic tectonic events are not reflected in the sequence stratigraphy on the basis of available data

geochemical and petrological evidence of the subduction of delaminated adriatic continental lithosphere in the genesis of the neogene quaternary magmatism of central italy abstract serri g innocenti f and manetti p 1993 geochemical and petrological evidence of the subduction of delaminated adriatic continental lithosphere in the genesis of the neogene quaternary magmatism of central italy in m j r wortel u hansen and r sabadini editors relationships between mantle processes and geological processes at or near the earth s surface tectonophysics 223 117 147 the neogene quaternary magmatism of the northern apenninic arc took place in four phases separated in space and time which become progressively younger from west to east phase i 14 ma phase ii 7 3 6 0 ma phase iii 5 1 2 2 ma phase iv 1 3 0 1 ma this magmatism is the result of the activation of three physically separate sources 1 the adriatic continental crust extracted from the mantle in the late proterozoic 2 a strongly refractory recently k enriched harzburgitic mantle located in the mechanical boundary layer mbl of the lithosphere and 3 a recently metasomatized cpx rich mantle compositionally variable from iherzolite to wehrlite clinopyroxenite interpreted as an ephemerally k enriched asthenosphere the adriatic continental crust is the dominant source of the acid plutonic and volcanic rocks of the tuscan region the acid magmatism is mostly found inside an ellipsoidal area about 150 300 km centred on giglio island here defined as the tuscan crustal dome within this area mantle derived magmas unaffected by important crustal contamination processes and mixing with crustal anatectic melts have so far not been found pure crustal magmas are rare but are represented for example by some of the san vincenzo and roccastrada rhyolites virtually all the tuscan acid centres show evidence of mixing with potassic mantle derived magmas major and trace elements as well as 87 sr 86 sr and 143 nd 144 nd data on primitive rocks mg 65 reveal two groups of mantle derived magmas these define two distinct mantle enrichment trends both essentially due to the additions of k rich components which metasomatized separate compositionally diverse upper mantle sectors in both cases the most remarkable mineralogical effect of these enrichment processes is the production of variable amount of phlogopite through reaction between fluids and or melts with the mantle the rocks of group i ol hy and q normative lamproites ultrapotassic high mg latites ultrapotassic shoshonites and shoshonites saturated trend are considered to be derived by partial melting at low pressure 87 sr 86 sr 0 717 ce sr 0 3 and k 2 o na 2 o 6 7 and low ratios of 143 nd 144 nd 0 5121 0 5120 and ba la 87 sr 86 sr 0 712 and k 2 o na 2 o 8 9 values and low 143 nd 144 nd ba la 0 10 ratios these constraints do not allow to exclude a complete identity between the k rich components which metasomatized the mantle sources of the saturated and undersaturated trend magmas the geochemical and isotopic features of the components that metasomatized the mantle sources of the northern apenninic arc magmatism can be explained by a geodynamic process which causes a large amount of crustal materials to be incorporated within the upper mantle we propose that the delamination and subduction of the adriatic continental lithosphere related to the still ongoing northern apennine continental collision provide a viable mechanism to explain the genesis and eastward discontinuous migration of the magmatism in central italy the subduction of delaminated lithospheric mantle with lower crustal slivers would have exposed uppermost mantle adriatic mbl and crustal units previously imbricated in the apennine chain to the heating advected by the upwelling of a recently and ephemerally k enriched asthenospheric mantle wedge and by the underplating of magmas derived from it we consider that the diapiric uprising of a hot crustally contaminated asthenosphere occurs in the wake left above the sinking of the adriatic delaminated subducting continental lithosphere the delamination subduction process of the adriatic lithosphere has probably started in the early middle miocene but earlier than 15 14 ma ago as indicated by the age and petrologic characteristics of the first magmatic episode sisco lamproite of the northern apennine orogenesis

from gullies to mountain belts a review of sediment budgets at various scales this paper reviews the state of the art in the concept as well as in the application of sediment budgets in sedimentary research sediments are a product of mass dispersal at the earth surface and take part in global cycles sediment budgets aim at quantifying this mass transfer based on the principle of mass conservation and are the key to determine ancient fluxes of solid matter at the earth surface this involves fundamental questions about the interplay of uplift climate and denudation in mountain belts and transfer of sediments from the continents to the oceans as well as applied issues such as soil and gully erosion reservoir siltation and coastal protection first after introducing basic concepts relevant scales and methodologies the different components of quaternary routing systems from erosion in headwaters river systems glacial and paraglacial systems lakes deltas estuaries coasts shelves epicontinental seas and deep sea fans are discussed in terms of their sediment budget most suitable are sedimentologically closed or semi closed depositional environments e g alluvial fans lakes deltas and deep sea fans in a second step the dynamics of passive active and collisional tectonic settings and sediment budgets in related sedimentary basins are explored and new concepts of sediment portioning at large geodynamic scales are introduced ancient routing systems are more or less incomplete and may be intensively fragmented or destroyed in active tectonic settings in terms of sedimentary basin types rifts intracontinental and epicontinental settings are preferred objects of sediment budgets because of their persistence and relatively simple overall sedimentary architecture however closing basins such as foreland forearc retroarc piggy back and wedge top basins may provide excellent snapshots of orogenic sediment fluxes in a third step the large long lived routing systems of the amazon the ganges brahmaputra and the rhine are reviewed for each system estimates of either sediment volumes mass or sediment fluxes of continental and marine subsystems have been compiled in order to receive a complete routing in terms of mass conservation for specific time periods since the late glacial maximum as well as the cenozoic following lessons can be taken from these case studies i depositional centers and fluxes show strong shifts in space and time and call for caution when simply looking at subsystems ii the response times of these large systems are within the milankovich time interval thus lower than predicted from diffusion models iii cyclic routing of sediments in continental basins is much more dominated by climate human control than by eustacy and iv at long time scales ultimate sinks win over intermittent storage it is concluded from this review that the quantitative understanding of global sediment cycling over historic and geologic time and its response to allogenic forcing is still in its infancy and further research is needed towards a holistic view of sediment routing systems at various temporal and spatial scales and their coupling with global biogeochemical cycles this includes i to better determine response times of large routing systems by linking quaternary with cenozoic sediment budgets and continental with marine sub systems ii to combine advanced provenance techniques with sediment budgets in order to reconstruct ancient systems iii to study sediment partitioning at the basin scale iv to reconcile continental supply dominated sequence stratigraphy with the eustatic dominated marine concept and iv to account for non actualism of ancient systems with respect to their erosion and transport mode in particular during glaciations and pronounced arid intervals glacial and eolian sediment routing may cross over hydrologic boundaries of drainage basins thus challenging the principle of mass conservation

the structure of the rockall trough from seismic refraction and wide angle reflection measurements there are few detailed descriptions of the deep crustal structure of failed cratonic rifts and passive margins despite their import ance in constraining the variety of structural models invoked to account for their common structural symmetry or gross half graben form1 3 such deep crustal structure profiles also have considerable value in defining the continent ocean boundary con straining plate reconstructions and determining the overall setting of sedimentary basin development the rockall trough in the north atlantic ocean is a sinuous elongate bathymetric depression 200 km wide and more than 2 000 m deep lying between rockall plateau and the british isles and the structure nature and age of its underlying crust are disputed in the absence of deep crustal structure profiles the presence of oceanic crust has been assumed because the trough has to be accommodated in reconstructions of the north atlantic although stretched continental crust is equally plausible the nature of the crust is important for the precise reconstruction of the late jurassic early cretaceous plate history and setting of sedimentary basins of the north atlantic4 8 the nature of the crust beneath the trough as well as the structure thickness and composition of the sedimentary cover is also relevant to oil exploration here we report the first observations of deep crustal structure across the rockall trough and its margins from seismic refraction and wide angle reflection profiles our results show that the northern rockall trough is underlain by highly stretched continental crust and not by oceanic crust as previously postulated

the sirente crater italy impact versus mud volcano origins the sirente crater is a circular structure with a diameter of 80 m the rim deposit is an inverse graded matrix supported breccia sedimentological features of the rim deposit suggest that the crater is not related to an explosion or violent mechanical displacement the structure and texture of the deposit exhibit a primary sedimentary character the rim deposits do not contain artifacts and do not show evidence of reworking a multistage formation is reconstructed for the rim growth and associated deposits the geometry and sedimentology of the deposits indicate that they were produced by the extrusion and accumulation of mudflow deposits the dominant ejection mechanism was low mud fountains and the transport medium was water petrographic and geochemical evidence does not indicate any physical or cryptic trace of an extraterrestrial body the most realistic agent that explains the observed effects is a rapid local emission of mud and or water geological processes capable of producing these features include piping sinkholes or more probably caldera type mud volcanoes which may result from underground water table perturbation and or decompression of deep co2 hydrocarbon gas reservoirs due to tectonic deformation or faulting activity during a seismic event in both cases the name crater for this geological form may be maintained but there is no compelling evidence for an impact origin in this paper the scientific literature on the sirente crater is reconsidered in the light of new morphological sedimentological geochemical and archaeological data a new mechanism is proposed involving mud fountaining

detrital zircon age constraints on basement history on the margins of the northern rockall basin detrital zircon dating has proven to be an effective way to constrain ages of submerged basement terranes on the margins of the northern rockall basin a region where direct evidence of crustal affinities is scarce or absent zircons have been dated from sandstones of palaeocene oligocene age known to have been derived from the east hebridean platform and west rockall and george bligh highs the results show that the hebridean platform is a westward extension of the lewisian complex with archaean and palaeoproterozoic ages that can be directly correlated with events identified in the outer hebrides and northwest scotland the detrital zircons derived from the hebridean platform also provide evidence for a mesoproterozoic thermal event and two phases of intrusions in the palaeozoic the rockall high consists of a palaeoproterozoic terrane dated as c 1760 1800 ma similar to ages previously determined from both basement samples and detrital sediment the data also provide evidence for the subsequent intrusion of alkaline igneous rocks in the palaeocene eocene the george bligh high represents an archaean terrane heavily affected by palaeoproterozoic tectonothermal events and was also the site of intrusion of alkaline igneous rocks in the palaeocene

interdisciplinary interpretation of challenging archives charcoal assemblages in drina valley alluvial and colluvial sediments jagnilo bosnia and herzegovina in connection to an archaeological project in bosnia and herzegovina charcoal fragments from several geomorphological profiles were analysed due to the lack of other archives for palaeoenvironmental reconstruction the major aim of the presented study was to systematically test the suitability of the documented colluvial and alluvial layers for charcoal analysis the profiles uncover main phases of sedimentation of drina valley holocene alluvial sedimentation and for the first time provide anthracological data from the area giving initial insight into the vegetation of the catchment areas and into dynamics of the drina for the late holocene the presence of several genera in the catchment areas of the investigated profiles was documented the most important genera are quercus and ostrya carpinus type fagus acer and pinus are also present light demanding genera such as corylus and the maloideae group indicate human activities alluvial elements such as ulmus fraxinus and alnus are present a major advantage of this investigation is the distinction of catchment areas for alluvial and colluvial layers by the means of charcoal analysis this interdisciplinary cooperation of botanists geoscientists and archaeologists yields new information about a rarely investigated region of southeastern europe and thus improves understanding of natural processes and human impact

review and update of the applications of organic petrology part 1 geological applications abstract organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry coal petrology was then considered a branch of coal science later with the development of specialized nomenclature classification of coal components and the standardization and improvement of analytical microscopical methods this discipline expanded in interests and name becoming organic petrology organic petrology carries a broader context being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources at present organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences throughout the 20th century several important monographs have been published on the discipline of organic petrology including stach s textbook of coal petrology 1st edition 1935 2nd 1975 3rd 1982 updated as the more general organic petrology by taylor et al 1998 more recently the text applied coal petrology the role of petrology in coal utilization was published by suarez ruiz and crelling 2008 this review is the first in a two part review series that describes and updates the role of organic petrology in geosciences a second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow

peraluminous igneous rocks as an indicator of thermogenic methane release from the north atlantic volcanic province at the time of the paleocene eocene thermal maximum petm unusual cordierite bearing peraluminous dacites produced by melting of organic rich sediments by intrusion of basaltic magma are found within the north atlantic volcanic province navp calculations suggest that formation of the dacites radiometric dated at 55 9 0 3 ma and possibly widespread could have released an average of 4 500 gt range from 3 000 to 6 000 gt of carbon as methane with a 13c of about 35 published model results suggest that such a methane release could explain the negative 13c excursion in the oceans and atmosphere the extreme global warming and the marked dissolution of carbonates in the deep oceans that accompanied the concurrent paleocene eocene thermal maximum petm outgassing from melting of sediments and formation of dacites possibly in conjunction with methane produced in contact metamorphic aureoles and by methane hydrate release provides a novel way of explaining the petm and its timing

magnetometer survey of the proposed sirente meteorite crater field central italy evidence for uplifted crater rims and buried meteorites the sirente crater field consists of a 120 m wide rimmed main depression flanked to the northwest by about 30 smaller depressions it has been dated to the first centuries a d an impact origin is suggested but not confirmed the small size combined with the properties of the target material carbonate mud would neither allow shock features diagnostic of impact nor projectile vaporization consequently a meteoritic component in the sediments would be very localized at impacts of this size the projectile most likely is an iron meteorite any iron meteorites on the ground surface would in iron age europe have been removed shortly after the event however if the depressions are of impact origin they should contain meteorites at great depth in analogy with known craters the magnetic properties of iron meteorites differ distinctly from the very low magnetic sediments and sedimentary rocks of the sirente area we have used a proton precession magnetometer gradiometer to produce magnetic anomaly maps over four of the smaller depressions 8 m diameter as well as two crossing profiles over a fifth depression 22 m diameter all show distinct magnetic anomalies of about 20 nt the larger depression up to 100 nt magnetic modeling shows a best fit for structures with upturned strata below their rims excluding a karstic origin but supporting an explosive formation the 100 nt anomaly can only be explained by highly magnetic objects at a few meters depth all together the magnetic data provides a strong indication for an impact origin of the crater field

from sedimentary records to sediment budgets multiple approaches to catchment sediment flux this paper reviews the traditional approach to sediment budget studies in geomorphology new approaches and more specifically the potential impact of new methodological advances each component of the budget is discussed including the spatial and volumetric estimations of erosion deposition and storage and the precision and accuracy of flux rate estimation examples are used from recent work in germany the netherlands and the uk and include the pedogenic approach to erosion estimation remote sensing lidar geophysics and sediment based dating techniques for flux rate estimation the precision and accuracy of catchment sediment flux estimates based upon sediment storage is not only dependant upon volumetric accuracy but also on the precision and accuracy of sediment dating in this area there has been a revolution with direct sediment dating techniques tl osl esr freeing budget studies from the constraints and biases of radiocarbon of particular importance is the use of cosmogenic nuclides for dating but which can also be used to derive long term erosion rates but only using a steady state assumption finally a tentative initial application of the sediment budget approach to pleistocene terrace staircase in unglaciated basins is discussed it is argued that only now do we have the techniques available to be able to produce accurate sediment budget estimations at spatial scales greater than that of zero order basins and over time periods greater than that covered by direct observations

osl dating of coarse grain fluvial quartz using single aliquot protocols on sediments from ne peloponnese greece abstract optical ages of quartz extracts in holocene sediments from the north eastern peloponnese greece are reported the single aliquot regenerative dose protocol proposed by murray and wintle 2000 radiation measurements 32 57 73 was used to estimate the equivalent dose in these samples a large inter aliquot scatter in d e values was observed for all samples this is ascribed to heterogeneous bleaching of the samples at deposition to estimate a d e for age calculation a technique is suggested based on the analysis of the d e scatter obtained from nine different quartz samples which were artificially bleached and irradiated this procedure is especially useful when the sample quantity is limited the optical age estimates increase with sampling depth an average aggradation rate of 1 5 mm yr is derived using the osl ages this value is consistent with the known uplift rate of 1 2 mm yr

pollen inferred late glacial and holocene climate in southern balkans lake maliq abstract high temporal resolution analysis of pollen records from lake maliq albania provides quantitative estimates of monthly temperature and precipitation changes since the last deglaciation the climate parameters were estimated using the best modern analogue technique with an updated modern pollen climate database composed of 2748 surface samples the record shows two main cooling phases in the maliq area the oldest and younger dryas and a cooling event around 8200 years which suggests that the forcing factors driving climate variations in the north atlantic area since the last glacial period also extended their influence into the mediterranean area the oldest and younger dryas are also characterized by an arid climate and a change in the seasonality of precipitation the summer precipitation tends to be greater during the cooling phases than during the temperate periods the holocene climate is relatively stable and the values of each parameter reach their modern levels except for an arid event between 8300 and 8100 cal bp

an assessment of human versus climatic impacts on holocene soil erosion in ne peloponnese greece soil erosion is a natural geomorphological process which can be triggered by both natural climate tectonics or both and anthropogenic e g agriculture perturbation of the ecosystem evidence has accrued that the holocene climate experienced large fluctuations in amplitude and suggestions of human impact on the ecosystem provided by the neolithic revolution dating back to the early holocene have been made the question of whether man or climate was the dominant factor responsible for holocene soil erosion remains unresolved to resolve the reasons for holocene sediment redistribution high resolution chronometric data on sediments derived from colluvial and alluvial archives from southern greece were obtained and combined with available archaeological and paleoclimatic data from the eastern mediterranean these data show a significant correlation between sedimentation rates and settlement history climatic fluctuations are only weakly correlated with sedimentation history the results show high sedimentation rates during the early neolithic 7th millennium bc in southern greece suggesting that holocene soil erosion was triggered by human activity and then amplified by enhanced precipitation this would explain the high sedimentation rates during the early neolithic in connection with enhanced precipitation in the eastern mediterranean which continued until the mid holocene

present and past soil erosion rates in catchments of the kraichgau area sw germany abstract in four catchments of the kraichgau area sw germany all covered with loess and distinguished by different combinations of natural and manmade erosion risks total and recent soil losses from the hills were examined the total loss was calculated as difference of quantities of soil material of the mapped soil units compared with a profile under erosion protection the recent loss on the basis of young sediments in the depression using contents of cadmium and lead to distinguish between old and young soil deposits in the depressions in two of the catchments total soil loss from the hills came up to about 90 of the formerly existing luvisol material total soil loss did not correlate with the natural erosion risks inclination slope length but recent soil loss correlated with the manmade erosion risks land utilisation type this recent soil loss ranged from less than 14 t ha 1 yr 1 in the catchment with terraced slopes to 84 t ha 1 yr 1 in a catchment with a high percentage of corn and sugar beet on the cultivated area and with large fields cultivated downslope in a similarly endowed catchment but with transversally cultivated fields a recent soil erosion of 39 t ha 1 yr 1 was calculated methodical problems are discussed

subsoil co2 and ch4 and their advective transfer from faulted grassland to the atmosphere measurements of co2 and ch4 in 3 m deep groundwater soil gas and soil atmosphere fluxes were completed in two grasslands in central italy having the same soil conditions but different subsoil fault linked secondary permeability unfaulted grassland displays gas phase equilibrium between soil air and groundwater typical soil gas diffusion profiles and diffusive soil to atmosphere gas transfer on the basis of oxygen depletion assessment assuming a ratio of 1 1 between biogenic o2 consumption and co2 production the measured soil co2 concentrations are consistent with a normal production in the soil by biologic activity the faulted grassland instead has higher co2 and ch4 concentrations up to 6 and 10 ppmv in soil air and flux 1 2 ml m 2 s 1 and 1 3 l m 2 s 1 resulting from a combination of soil biologic and endogenous components with evidence of gas transfer from the saturated to the unsaturated zone and advective gas transfer from soil to the atmosphere the extra soil source in the faulted zone which is about 0 3 4 times the background soil biologic production is likely related to migrating crustal gas whatever the c gas origin and depth may be biogenic or abiogenic shallow or deep the present results demonstrate that the subsoil derived component occurring in the soil in areas with active tectonics cannot be ignored a priori in the assessment of the c terrestrial sources in particular the assumption that dryland soils are sinks for methane owing to methanotrophic consumption may be not true in areas affected by active and gas bearing faults accordingly it would be very important to assess at global scale the actual role in the carbon dioxide and methane cycle of soils within the active tectonic bounds

the sirente crater field italy revisited 1 a scientific debate has developed in the last few years as to whether a 130 m diameter sag pond surrounded by a saddle shaped rim and neighboring smaller sags from the sirente plain abruzzi italy represent the only known italian meteoritic crater field a mud volcano or an anthropogenic feature to decipher the nature of the sirente landforms we carried out geophysical and geochemical investigations geoelectric profiles document two karstified shelf carbonate ridges lying at 10 40 m depth below calcareous lacustrine silts and deeper more conductive sediments likely soils tephra filling the plain the smaller sags lie just above the ridges implying a karstic origin whereas the main sag also resting above a carbonate ridge shows no roots in excess of 10 20 m depth in contrast to the crater interpretation high resolution magnetic surveys reveal negative positive anomaly stripes in correspondence with the buried ridges valleys respectively the smaller sags as well as the main crater are located in the domain of negative residuals the positive long wavelength magnetic signature is likely due to the strongly susceptive soils tephra filling the buried valleys magnetic modeling shows that the field observed over the crater is incompatible with the field generated by a buried meteorite with realistic characteristics the smaller sags are characterized by small magnetic anomaly couplets perfectly reproducible considering the susceptibility contrast between the fill in soil and the surrounding silts our data show that the sirente crater and the minor depressions are simply the results of human activity and karstic processes respectively

the structure and subsidence of rockall trough from two ship seismic experiments coincident multichannel seismic reflection and refraction profiles acquired northwest of britain during a two ship seismic experiment in the southern rockall trough provide evidence for a thin 6 km syn rift crust below rockall trough the variation of seismic velocity with depth is consistent with either oceanic crust similar to that found in other parts of the north atlantic or with thinned continental crust heavily intruded by syn rift igneous rocks the syn rift crust beneath rockall trough is now buried by nearly 5 km of sediments that are intruded by tertiary volcanics varying in extent from isolated sills to a large sill complex extending 100 km laterally the basement imaged on seismic profiles exhibits a band of subhorizontal reflectors that extend laterally over distances of up to 40 km which they interpret as sediments intercalated with submarine lava flow generated during the opening of the trough estimates of stretching from crustal thinning and from subsidence indicate that rockall trough has undergone extensive rifting beta 6 upwelling asthenosphere beneath the thinned lithosphere generated at least 1 3 km thickness of melt as it decompressed the molten rock rose upward from the mantle until it was in part extruded as lava flows and in partmore intruded into the crust less

historical soil erosion by water in germany scales and archives chronology research perspectives abstract the published record of historical soil erosion by water in germany as deduced from dated slope deposits n 306 alluvial sediments n 120 and lake sediments is summarized in this paper the number of sediments investigated reflects the state of knowledge chronology of historical soil erosion and to a certain degree the intensity of the human impact on german landscapes during the holocene even though few data of calculated historical soil erosion intensities exist an estimation of historical soil erosion in germany combining the available data has been calculated soil erosion in germany occurred first locally during the early holocene probably triggered by climatic variability from the neolithic onward the record reflects the human impact according to agricultural land use the observed variability indicates phases of weaker and regained intensity of agricultural land use in germany few records characterise the early and middle bronze age ca 2000 1600 bc and the migration period and the early medieval times ca 400 1000 ad surprisingly for the roman emperor times ca 1 400 ad a decreasing number of soil sediments is recorded even when the data from southern germany is examined separately phases characterised by an increase in soil erosion were the late bronze age and pre roman iron age ca 1600 bc 1 ad the high and late medieval times ca 1000 1350 ad and the modern times ca 1500 ad until today some extraordinary heavy precipitation events late 18th early 19th first half of 14th century pre roman iron age topped the even high soil erosion intensities research gaps as well as potential for future research as derived from the available data are outlined

colluvial and alluvial response to land use change in midland england an integrated geoarchaeological approach this paper presents geomorphic soils and palaeoecological data from a small sub catchment in the english midlands in an attempt to provide an integrated picture of holocene landscape change the area used has also been the focus of a multi disciplinary and long term archaeological survey raunds area project and so has a wealth of archaeological and historical data which can be related to the environmental record the paper combines these data much of which are only published in the archaeological literature with new interpretations based upon unpublished data and new data particularly from the hillslopes and new radiocarbon dating from the valley floor it is inferred that despite a long history of pastoral and arable agriculture since the neolithic bronze age colluviation on lower slopes significant soil redistribution and overbank alluviation only began to a measurable extent in the late saxon medieval period 9th century ad onwards it is suggested that this is due to a combination of land use factors principally the laying out of an intensive open field system and the establishment of villages combined with a period of extremes in climate well known throughout europe indeed the critical element appears to have been the social changes in this period that created this regionally distinctive landscape which happened to have a high spatial connectivity and facilitated intensive arable production with high tillage rates intense rainfall events during this period could therefore detach and mobilize high volumes of soil and the open field system facilitated transport to slope bases and valley floors the need for detailed and spatially precise land use data in order to interpret accelerated landscape change is stressed

mesozoic rocks from the hebrides shelf and implications for hydrocarbon prospectivity in the northern rockall trough abstract shallow boreholes drilled in the west lewis and west flannan basins outer hebrides shelf have proved rocks of probable latest bajocian bathonian to barremian age where previously a mainly permo triassic infill has been assumed the full geological succession of the basins remains unproved although the permo triassic history of the basins may be similar the rocks encountered suggest that the basins may have dissimilar geological histories during the jurassic and early cretaceous lithologies are mainly fine grained poorly sorted sandstones or organic rich mudstones some correlation can be made with the isle of skye and the west shetland area the sandstones are poor hydrocarbon reservoirs but the middle jurassic and ryazanian mudstones although immature where drilled have excellent oil source rock potential and may have generated large amounts of hydrocarbons if they are present at depth in the adjacent northern rockall trough

geochemistry of organic rich cretaceous and jurassic mudstones in the west lewis and west flannan basins offshore north west scotland implications for source rock presence in the north east rockall trough the west lewis and west flannan basins serve as important calibration sites for understanding the source rock distribution and quality in the north eastern part of the rockall trough in the west lewis basin two shallow boreholes penetrated organic rich oil prone bathonian mudstones which were deposited in a fresh to brackish water environment these mudstones will generate oils rich in paraffins upon maturation organic rich oil prone ryazanian mudstones were discovered in both the west lewis and west flannan basins they are offshore marine mudstones with a predominance of algal organic matter akin to the kimmeridge clay in the north sea and basins west of shetland the bathonian mudstones will generate their hydrocarbon products at higher temperatures than the ryazanian mudstones the presence of lower cretaceous and middle jurassic oil prone mudstones in basins on the hebrides shelf is intriguing and suggests that similar source rocks may be present along the north eastern margin of the rockall trough

unusual triterpane distributions in lacustrine oils abstract a series of diahopanes and a second unknown early eluting series of triterpanes are reported in lacustrine oil samples from three different basins we suggest that these compounds together with 18 h 30 norneohopane show distributions which vary with the salinity of the depositional environment

control of hydrocarbon seepage intensity on level of biodegradation in sea bottom sediments offshore surface geochemical surveys which target the surface expression of potential migration pathways for sampling such as fault scarps or diapiric features have become a commonly applied approach in the petroleum industry results of such surveys help to reduce risk on key exploration play elements and are used to evaluate prospects and to predict hydrocarbon phase and expected properties based on geochemical surveys conducted by exxonmobil in many basins worldwide there is an interrelation of the seep intensity concentration and level of biodegradation results from offshore west africa where many active macroseeps show moderate to severe biodegradation and a frontier basin offshore united kingdom rockall trough where active microseeps show no evidence of biodegradation are compared the specific biochemical controls on the difference in biodegradation proneness are not known although it appears that a certain threshold of oil concentration is needed to sustain an active bacterial community or to exceed clay adsorption capacities that may protect microseeps from biodegradation it is notable that the 25 norhopane series often considered an indication of severe biodegradation in reservoir oils has not been recognized in even ultra severely biodegraded seeps this suggests that different biodegradation pathways may be followed in marine surface seeps versus those in subsurface hydrocarbon accumulations a likely scenario in light of the fact that physiologically diverse bacterial communities are prevalent under different physiochemical conditions

an anthropogenic origin of the sirente crater abruzzi italy in this paper we review the recent hypothesis based mostly on geomorphological features that a 130 m wide sag pond surrounded by a saddle shaped rim from the sirente plain abruzzi italy is the first discovered meteoritic crater of italy sub circular depressions hosting ponds with geomorphological features and size very similar to those exhibited by the main sirente sag are exposed in other neighboring intermountain karstic plains from abruzzi we have sampled present day soils from these sag ponds and from the sirente sags both the main crater and some smaller ones recently interpreted as a crater field and various abruzzi paleosols from excavated trenches with an age range encompassing the estimated age of the sirente crater for all samples we measured the magnetic susceptibility and determined the ni and cr contents of selected specimens the results show that the magnetic susceptibility values and the geochemical composition are similar for all samples from sirente and other abruzzi sags and are both significantly different from the values reported for soils contaminated by meteoritic dust no solid evidence pointing at an impact origin exists besides the circular shape and rim of the main sag the available observations and data suggest that the sirente crater together with analogous large sags in the abruzzi intermountain plains have to be attributed to the historical phenomenon of transumanza seasonal migration of sheep and shepherds a custom that for centuries characterized the basic social economical system of the abruzzi region such sags were excavated to provide water for millions of sheep which spent summers in the abruzzi karstic high pasture lands on carbonatic massifs deprived of natural superficial fresh water conversely the distribution of the smaller sags from the sirente plain correlates with the local pattern of the calcareous bedrock and together with the characteristics of their internal structure are best interpreted as natural dolines in fact reported radiocarbon ages for the formation of the main sag pond and of the smaller sags differ significantly by more than two millennia thus excluding that they were all contemporaneously formed by a meteoritic impact

patterns of human occupation during the early holocene in the central ebro basin ne spain in response to the 8 2 ka climatic event abstract the central ebro river basin ne spain is the most northern area of truly semi arid mediterranean climate in europe and prehistoric human occupation there has been strongly influenced by this extreme environmental condition modern climate conditions single out this region due to the harsh environment characterised by the highest absolute summer temperatures of the ebro river basin the bajo aragon region se ebro river basin was intensively populated during the early holocene 9400 8200 cal yr bp but the settlements were abandoned abruptly at around 8200 cal yr bp we propose that this archaeological silence was caused by the regional impact of the global abrupt 8 2 ka cold event available regional paleoclimate archives demonstrate the existence of an aridity crisis then that interrupted the humid early holocene that environmental crisis would have forced hunter gatherer groups from the bajo aragon to migrate to regions with more favourable conditions i e more humid mountainous areas and only return in the neolithic coherently archaeological sites persist during this crisis in the nearby iberian range maestrazgo and the north ebro river area pre pyrenean mountains and along the northwestern ebro basin

past hydrological events reflected in the holocene fluvial record of europe abstract a comprehensive database of radiocarbon dated fluvial units in great britain poland and spain has been compiled to investigate the relationship between environmental change flooding and holocene river dynamics following the methodology recently developed by macklin and lewin macklin m g lewin j 2003 river sediments great floods and centennial scale holocene climate change journal of quaternary science 18 101 105 radiocarbon dates in fluvial sequences that coincide with a modification in sedimentation rate or style have been highlighted allowing geomorphologically significant changes in holocene river activity to be identified data analysis has been undertaken at both national and sub national scales and on catchments of different size type and land use history multiple phases of higher flood frequency characterized by accelerated erosion and sediment deposition on floodplains are recognized and compared with a range of climate proxies the relative and varying roles of climate and land use on river dynamics are considered and the value of the database for reconstructing past hydrological events as well as for predicting river response to future environmental change is assessed

younger dryas to mid holocene environmental history of the lowlands of nw transylvania romania pollen micro charcoal and total carbon analyses on sediments from the turbuta palaeolake in the transylvanian basin of nw romania reveal younger dryas to mid holocene environmental changes the chronostratigraphy relies on ams 14c measurements on organic matter and u th tims datings of snail shells results indicate the presence of pinus and betula open woodlands with small populations of picea ulmus alnus and salix before 12 000 cal yr bp a fairly abrupt replacement of pinus and betula by ulmus dominated woodlands at ca 11 900 cal yr bp likely represents competition effects of vegetation driven by climate warming at the onset of the holocene by 11 000 cal yr bp the woodlands were increasingly diverse and dense with the expansion of quercus fraxinus and tilia the establishment of corylus and the decline of upland herbaceous and shrubs taxa the marked expansion of quercus accompanied by tilia between 10 500 and 8000 cal yr bp could be the result of low effective moisture associated with both low elevation of the site and with regional change towards a drier climate at 10 000 cal yr bp corylus spread across the region and by 8000 cal yr bp it replaced quercus as a dominant forest constituent with only little representation of picea abies carpinus became established around 5500 cal yr bp but it was only a minor constituent in local woodlands until ca 5000 cal yr bp results from this study also indicate that the woodlands in the lowlands of turbuta were never closed

holocene flood histories in south western usa harden t macklin m g baker v r 2010 holocene flood histories in south western usa earth surface processes and landforms 35 6 707 716 sponsorship aberystwyth university university of arizona

the geology of the uk hatton rockall margin abstract seismic potential field sea bed sample and shallow drilling data have been used to investigate the geology of the uk part of the rockall plateau most of the rockall plateau is underlain by early proterozoic rockall bank islay terrane metamorphic basement although george bligh bank and the north eastern end of hatton bank may be underlain at depth by lewisian rocks the basement crops out on rockall bank but occurs at a much deeper level beneath hatton bank and hatton basin the widespread palaeogene lavas of rockall plateau have been sourced from large central igneous complexes rockall swithin sandastre mammal lyonesse and sandarro local volcanoes and fissures some of the lavas may also have been derived from the incipient rift axis west of hatton bank at the time of continental break up differences in seismic facies allow the extent of the lavas from the large centres to be mapped where the lavas are absent beneath parts of hatton bank either due to non emplacement or subsequent erosion during the cenozoic seismic data image the underlying mesozoic and older rocks here bgs boreholes 99 1 and 99 2a have proved mid cretaceous albian shales and sandstones respectively beneath a thin cenozoic cover the mesozoic and older rocks appear to be quite extensive and are folded and faulted mesozoic strata are not observed on rockall bank in uk waters the post lava cenozoic succession of rockall plateau can be sub divided into three megasequences separated by two unconformities which by analogy with rockall basin have been designated c30 intra late eocene and c10 intra early pliocene the ages can be corroborated by dsdp odp boreholes in the hatton basin the cenozoic succession contains eocene prograding fan sequences contourite deposits on the flanks of the banks and shallow faulting some of which affects the present day sea bed structurally rockall high appears mainly as a large basement block whereas hatton high is more complex exhibiting half grabens inversion structures and reverse fault geometries due to cenozoic tectonism the northern end of hatton high is a large anticline with its axis aligned ene wsw the structural differences between the highs may be due to their locations with rockall high exhibiting fewer tectonic effects due to its more landward intraplate setting further away from plate margin deformation

a new look at the rockall region offshore ireland abstract a 700 km wide angle reflection refraction profile carried out in the central north atlantic west of ireland crossed the erris trough rockall trough and rockall bank and terminated in the western hatton rockall basin the results reveal the presence of a number of sedimentary basins separated by basement highs the rockall trough with a sedimentary pile up to 5 km thick is underlain by thinned continental crust 8 10 km thick some major fault block structures are identified especially on the eastern margin of the rockall trough and in the adjacent erris trough the hatton rockall basin is underlain by westward thinning continental crust 22 10 km thick sedimentary strata are up to 5 km thick the strata in the rockall trough and hatton rockall basin probably range in age from late palaeozoic to cenozoic however the basins have different sedimentation histories and differ in structural style the geometry of the crust and sediments suggests that the rockall trough originated by pure shear crustal stretching associated with rift deposits and cenozoic thermal sag strata in contrast the development of the erris trough located on unthinned continental crust was facilitated by shallow brittle extension with little deep crustal attenuation a two layered crust occurs throughout the region the lower crustal velocity in the hatton rockall basin is higher than that in the rockall trough the velocity structure shows no indication of crustal underplating by upper mantle material in the region

the history of soil erosion and fluvial deposits in small catchments of central europe deciphering the long term interaction between humans and the environment a review abstract during the last few decades many case studies focused on the dynamics of fluvial systems in response to hillslope erosion land use impact and climate changes this paper will review the current state of knowledge of the dynamics of past soil erosion and gullying in small catchments

a 12 000 year pollen record from lake maliq albania abstract pollen data from lake maliq the first from albania contribute new information to the discussion of the vegetational hydrological and climatological history of the balkans since 12 000 yr b p during late glacial time a perennial lake expanded at maliq it was surrounded by a complex vegetation association composed of steppe and mixed forest elements the highly diverse forest flora suggest that late glacial forest refugia were more developed here at middle altitude rather than at higher altitude as previously suggested the forest developed after 9800 yr b p while the water level remained high in the korce basin until 5000 yr b p different environmental conditions characterized by lower available moisture and warmer winters progressively took place after this date human activity in the korce basin ca 4500 yr b p was coeval with conditions characterized by an increase in winter temperatures and a decrease in summer moisture

climate forcing due to the 8200 cal yr bp event observed at early neolithic sites in the eastern mediterranean we explore the hypothesis that the abrupt drainage of laurentide lakes and associated rapid switch of the north atlantic thermohaline circulation 8200 yr ago had a catastrophic influence on neolithic civilisation in large parts of southeastern europe anatolia cyprus and the near east the event at 8200 cal yr bp is observed in a large number of high resolution climate proxies in the northern hemisphere and in many cases corresponds to markedly cold and arid conditions we identify the relevant archaeological levels of major neolithic settlements in central anatolia cyprus greece and bulgaria and examine published stratigraphic architectural cultural and geoarchaeological studies for these sites the specific archaeological events and processes we observe at a number of these sites during the study interval 8400 8000 cal yr bp lead us to refine some previously established neolithisation models the introduction of farming to south east europe occurs in all study regions thrace macedonia thessaly bulgaria near 8200 cal yr bp we observe major disruptions of neolithic cultures in the levant north syria south east anatolia central anatolia and cyprus at the same time we conclude that the 8200 cal yr bp aridity event triggered the spread of early farmers by different routes out of west asia and the near east into greece and bulgaria

palaeoclimate and the formation of sapropel s1 inferences from late quaternary lacustrine and marine sequences in the central mediterranean region abstract synchronous responses to climatic changes during the late pleistocene holocene transition are inferred from marine and lacustrine stratigraphic records in the central mediterranean region new stratigraphic data are presented from well dated sequences in the meso adriatic depression mad two crater lakes in the lazio region and in the tyrrhenian sea the sequences all span the last termination and the holocene but we focus here on the evidence in each record for the time period during which sapropel s1 formed in the mediterranean ca 9 0 to 6 8 cal kyr b p the new records provide evidence of palaeoenvironmental changes on land and sea that can be reconstructed at a high temporal resolution and which throw some light on the processes which led to the formation of s1 the collective evidence indicates that i organic rich sediments occurred in both the marine and the crater lake sites during the time of formation of the s1 sapropel ii there is evidence of increased stratification and anoxia in the sea water column during the period of s1 formation iii the s1 period in the study area is divisible into two sub phases s1a and s1b which reflect short term variations in oceanographic conditions stratification and anoxia iv changes in stratification in the marine column were contemporaneous with regional climate variations that are inferred from the terrestrial records we conclude that the key factor that initiated the formation of s1 was increased discharge of freshwater into the mediterranean following a change post 9 0 cal kyr b p to a warmer and wetter climate furthermore the period of s1 formation was interrupted by a short lived episode ca 500 years of comparatively cooler and drier conditions during the early middle holocene transition emht

european lakes as palaeohydrological and palaeoclimatic indicators abstract lakes in temperate regions have fluctuated in size on annual to millenial time scales changes in water level or depth can be reconstructed by applying geomorphic sedimentological and biostratigraphic methods to transects of sediment cores this systematic field based approach has been used at a number of sites in europe it is illustrated by reconstructions of water level changes in lakes from southern sweden these lakes have shown broadly synchronous changes during the holocene such synchronous changes in water levels at several sites in a region reflect climatic changes inferences about the mechanism of the climatic change depend on identifying both synchronous changes within a region and differences in the direction magnitude and timing of lake level changes between regions continental compilations of lake level data are therefore necessary detailed studies are not available from enough sites but the interpretation of already existing stratigraphic and biostratigraphic data in terms of lake level changes has greatly increased the number of sites available for a continental scale synthesis in europe this eclectic literature based approach is illustrated with examples from southern europe lakes in the mediterranean region were high around the glacial maximum and again somtime during the first half of the holocene in the western mediterranean the peak of late glacial aridity occurred at 15 000 16 000 bp and the lakes were already high again by 12 000 bp in the east maximum late glacial aridity occurred between 13 000 and 11 000 bp and there was a gradual return to wetter climates during the early holocene such that 9000 bp was more arid than 6000 bp most lakes in the mediterranean region were high at 6000 bp the transition to arid conditions after 5000 bp occurred abruptly in the west and more gradually in the east the lakes of southern sweden indicate drier climates in the early holocene ca 9000 bp more effective moisture between 8000 and 6000 bp increased aridity between 5500 and 3500 bp and increased effective moisture again during the last 3000 years the history of lake level changes in southern sweden and the mediterranean region can be partially explained in terms of changes in the direct effects of insolation and in the strength and position of the westerlies and of the subtropical high pressure cell during the late quaternary

holocene river activity analysing 14c dated fluvial and colluvial sediments from germany records of fluvial dynamics in response to long term changes of climate and land use impacts are rare therefore cumulative probability functions cpfs of 401 14c ages originating from german rivers and hillslopes were compiled to reconstruct phases of increased geomorphic activity and stability during the holocene an improved analytical method is suggested to normalise cpfs and eliminated the effects of wiggles of the calibration curve and the young age bias nine periods of activity are identified peaking at 7050 6250 5525 3690 2250 1350 820 325 bc and since 875 ad and are compared with climatic palaeohydrological and human impact proxy data until 2250 bc events of geomorphic activity are mainly coupled to wetter and or cooler climatic phases due to growing population and intensive agricultural activities during the bronze age the increased geomorphologic activity between 1300 and 820 bc cannot unequivocally be related to climate since 875 ad the growing population density is considered as the major external forcing differential geomorphic activity of hillslopes and floodplains suggest that the hillslope channel coupling during the holocene is mainly controlled by human impact with a strong increased coupling after 1500 bc

holocene river and slope activity in the visoko basin bosnia herzegovina climate and land use effects alluvial and colluvial deposits were investigated at prehistoric tells close to the bosna river the chronology is based on ten radiocarbon ages five optically stimulated luminescence ages and on the archaeological record fluvial activity of the bosna river is indicated by overbank fines ca 5000 1000 bc 500 bc until today and a phase of lateral displacement of the river bed with subsequent channel fills ca 2000 500 bc early holocene fluvial activity was probably triggered by climatic variability but might have promoted the expansion of neolithic societies into the visoko basin mid to late holocene river activity occurred under increased climatic aridity but coincided with the expansion of prehistoric settlements to a wider area of the river basin on hard rocks in the adjacent mountainous areas the destruction of the thin soil cover in the mountains is discussed as a probable trigger for enduring subsequent river activity this is also indicated by a change in the geochemical signature of the alluvial sediments the proposed mechanism might explain the mid to late holocene river history in other regions the potential of geochemical analyses and diachronous high resolution archaeological records to make inferences regarding sediment sources and geomorphological processes is demonstrated copyright 2013 john wiley sons ltd