formal definition and dating of the gssp global stratotype section and point for the base of the holocene using the greenland ngrip ice core and selected auxiliary records the greenland ice core from northgrip ngrip contains a proxy climate record across the pleistocene holocene boundary of unprecedented clarity and resolution analysis of an array of physical and chemical parameters within the ice enables the base of the holocene as reflected in the first signs of climatic warming at the end of the younger dryas greenland stadial 1 cold phase to be located with a high degree of precision this climatic event is most clearly reflected in an abrupt shift in deuterium excess values accompanied by more gradual changes in d 18 o dust concentration a range of chemical species and annual layer thickness a timescale based on multi parameter annual layer counting provides an age of 11 700 calendar yr b2 k before ad 2000 for the base of the holocene with a maximum counting error of 99 yr a proposal that an archived core from this unique sequence should constitute the global stratotype section and point gssp for the base of the holocene series epoch quaternary system period has been ratified by the international union of geological sciences five auxiliary stratotypes for the pleistocene holocene boundary have also been recognised copyright 2008 john wiley sons ltd

global dinoflagellate event associated with the late paleocene thermal maximum the late paleocene thermal maximum or lptm ca 55 ma represents a geologically brief time interval 220 k y characterized by profound global warming and associated environmental change the lptm is marked by a prominent negative carbon isotope excursion cie interpreted to reflect a massive and abrupt input of 12 c enriched carbon to the ocean atmosphere reservoir possibly as a result of catastrophic gas hydrate release on time scales equivalent to present day rates of anthropogenic carbon input the lptm corresponds to important changes in the global distribution of biota including mass extinction of marine benthic organisms the dinoflagellate cyst record indicates that surface dwelling marine plankton in marginal seas also underwent significant perturbations during the lptm we report on the dramatic response of representatives of the genus apectodinium from two upper paleocene lower eocene sections in the southern new zealand and northern austria hemispheres where the dinoflagellate records are directly correlated with the cie benthic foraminifera extinction event and calcareous nannofossil zonation the results indicate that the inception of apectodinium dominated assemblages appears to be synchronous on a global scale and that the event is precisely coincident with the beginning of the lptm apectodinium markedly declined in abundance near the end of the lptm this apectodinium event may be associated with 1 exceptionally high global sea surface temperatures and or 2 a significant increase in marginal marine surface water productivity such a globally synchronous acme of dinoflagellate cysts is unprecedented within the dinoflagellate cyst fossil record

invasion of anthropogenic co2 recorded in planktonic foraminifera from the northern gulf of aqaba the stable carbon isotopic composition of the planktonic foraminifera globigerinoides sacculifer and g ruber white and sedimentary organic matter from the northern gulf of aqaba have been investigated to estimate changes in 13cdic in surface waters during the last 1 000 years the high sedimentation rates at the core sites about 54 cm kyear provide high temporal resolution 10 years recent sediments at the top of the cores reflect conditions younger than 1950 the 13c records of the planktonic foraminifera from three multicores display similar trends showing a uniform and consistent pattern before the 1750s and a gradual decrease of approximately 0 63 over the last two centuries this decrease seems to track the decrease of 13cdic in surface waters which is mainly caused by the increase of anthropogenic input of 13c depleted co2 into the atmosphere similarly a trend towards lighter values of the carbon isotopic composition of sedimentary organic matter 13corg during the last 200 years supports the interpretation obtained from the planktonic foraminiferal 13c furthermore direct measurements of seawater show that 13c of the dissolved inorganic carbon dic in the northern gulf of aqaba has decreased by about 0 44 during the period 1979 2000 the average annual decrease is 0 021 which is similar to that observed globally the 13c values of planktonic foraminifera combined with organic matter 13c from marine sediments are good indicators for reconstructing past changes in atmospheric co2 concentrations from the northern gulf of aqaba

rapid alluvial sedimentation aided expansion of moissac during the high middle ages along the tarn river in southern france abstract we examine medieval urban expansion of moissac a town located at the outlet of the tarn river basin draining 15 400 km2 in southern france in order to understand the association of moissac s expansion to river position and sedimentation patterns in the river valley a chronostratigraphic framework was derived from three auger holes and an archaeological excavation using radiocarbon dating and standard field and laboratory characterization of sediments five radiocarbon dates were obtained from one auger hole along with particle size magnetic susceptibility organic matter and quantitative soil color analyses to augment field descriptions results indicate moissac spawned from the abbey of saint pierre on the apex of a small alluvial fan surrounded by backswamps ca 850 ce and urban growth radiated down the fan toward the river bottomlands throughout the following several centuries at ca 1000 1200 ce human induced soil erosion in the watershed caused very rapid aggradation of surrounding alluvial backswamps at long term average sedimentation rates of 20 30 mm y such rapid bottomland accretion probably was driven by rampant agricultural soil erosion linked with wet climatic periods and enhanced flooding this bottomland accretion enabled urban expansion and agricultural activities to cover the former backswamp and wetlands by the late middle ages ca 1300 1500 ce although we normally associate human induced soil erosion with negative consequences of ecosystem services the rapid bottomland accretion and resulting habitable and arable land can be viewed as a positive ecosystem service outcome resulting from human induced soil erosion

stratigraphy of the anthropocene the anthropocene an informal term used to signal the impact of collective human activity on biological physical and chemical processes on the earth system is assessed using stratigraphic criteria it is complex in time space and process and may be considered in terms of the scale relative timing duration and novelty of its various phenomena the lithostratigraphic signal includes both direct components such as urban constructions and man made deposits and indirect ones such as sediment flux changes already widespread these are producing a significant event layer locally with considerable long term preservation potential chemostratigraphic signals include new organic compounds but are likely to be dominated by the effects of co2 release particularly via acidification in the marine realm and man made radionuclides the sequence stratigraphic signal is negligible to date but may become geologically significant over centennial millennial time scales the rapidly growing biostratigraphic signal includes geologically novel aspects the scale of globally transferred species and geologically will have permanent effects

anthropogenic contribution to the geological and geomorphological record a case study from great yarmouth norfolk uk abstract reconstruction of artificial or anthropogenic topographies sediment thicknesses and volumes provides a mechanism for quantifying anthropogenic changes to sedimentary systems in the context of the proposed anthropocene epoch we present a methodology for determining the volumetric contribution of anthropogenic deposits to the geological and geomorphological record and apply it to the great yarmouth area of norfolk uk 115 boreholes drilled to a maximum depth of 6 m below ground level were used to determine the thickness and distribution of seven geo archaeological units comprising natural and anthropogenic deposits in the central great yarmouth area this was supplemented by additional depth information derived from 467 existing ground investigation boreholes and published 1 50 000 scale geological maps the top and base of each geo archaeological unit were modelled from elevations recorded in the borehole data grids were produced using a natural neighbour analysis with a 25 m cell size using mapinfo 8 0 vertical mapper 3 1 to produce palaeotopographical surfaces maximum minimum and average elevations for each geo archaeological unit generally increase with decreasing age with the exception of the early medieval palaeotopographical surface which locally occurs at higher elevations than that of the younger late medieval unit the total sediment volume for the combined modern post medieval late medieval and early medieval geo archaeological units is 10 91 10 5 m 3 the total sediment volume for the aeolian river terrace and marine geo archaeological units combined is 65 58 10 5 m 3 anthropogenic sedimentation rates were calculated to increase from 590 m 3 yr during the early medieval period 1500 m 3 yr during the post medieval period and 2300 m 3 yr during the modern period it is estimated that the combined anthropogenic geo archaeological units contribute approximately 15 of the total volume of sediments that would have been traditionally considered natural holocene deposits in the great yarmouth area the results indicate that an approach combining geological and archaeological deposit modelling can be used to quantify anthropogenic landscape impact and its associated sediment flux

the palaeolimnology of the aral sea a review abstract formerly the fourth largest inland water body in the world the volume and area of the aral sea have decreased dramatically over the past 30 yr largely as a result of human actions throughout its approximately 2 million year history the fate of this water body has been intimately linked with that of its two main in flowing rivers the amu darya and the syr darya we present a review of the hydrological palaeontological and sedimentological evidence for the evolution of the aral sea based largely on russian literature although the structure of the aral basin can be traced back to the late neogene the sea has only existed in its present form for the past 8 10 ka and the holocene history has been shaped by regional climatic variations the development of the associated drainage system and anthropogenic forces past hydrological changes in the aral basin have led to systematic shifts in the level of the aral sea which are reflected sedimentologically through the deposition of transgressive and regressive sedimentary units and geomorphologically through the development of terraces all the above data are integrated to produced a late quaternary history of this important water body

coastal ocean co2 carbonic acid carbonate sediment system of the anthropocene 1 there is little doubt that human activities such as burning of fossil fuels and land use practices have changed and will continue to change the cycling of carbon in the global coastal ocean in the present study two biogeochemical box models were used to investigate the consequences of increasing atmospheric co2 and subsequent ocean acidification and increasing riverine transport of organic matter and nutrients arising from human activities on land on the global coastal ocean between the years 1700 and 2300 numerical simulations show that the net flux of co2 between coastal ocean surface water and the atmosphere is likely to change during this time from net evasion to net invasion owing to increasing atmospheric co2 increasing net ecosystem production arising from increasing nutrient loading to this region and decreasing net ecosystem calcification due to lower carbonate ion concentration and subsequent lower surface water saturation state with respect to carbonate minerals model calculations show that surface water saturation state with respect to calcite will decrease 73 by the year 2300 under a business as usual scenario which in concert with increasing temperature will cause overall biogenic calcification rate to decrease by 90 dissolution of carbonate minerals increased by 267 throughout the model simulation this increase was in part due to increased invasion of atmospheric co2 but mainly due to greater deposition and remineralization of land derived and in situ produced organic matter in the sediments producing co2 that caused pore water ph and carbonate saturation state to decrease this decrease in turn drove selective dissolution of metastable carbonate minerals as a consequence the relative carbonate composition of the sediments changed in favor of carbonate phases with lower solubility than that of an average 15 mol magnesian calcite phase model projected changes in surface water carbonate saturation state agree well with observations from the hawaiian ocean time series and the calculated air sea co2 exchange agrees well with a recent independent estimate of this flux derived from measurements from diverse coastal ecosystems scaled up to the global coastal ocean area

the chicxulub asteroid impact and mass extinction at the cretaceous paleogene boundary the cretaceous paleogene boundary similar to 65 5 million years ago marks one of the three largest mass extinctions in the past 500 million years the extinction event coincided with a large asteroid impact at chicxulub mexico and occurred within the time of deccan flood basalt volcanism in india here we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction notably a single ejecta rich deposit compositionally linked to the chicxulub impact is globally distributed at the cretaceous paleogene boundary the temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations for example darkness and cooling lead us to conclude that the chicxulub impact triggered the mass extinction

eight glacial cycles from an antarctic ice core the antarctic vostok ice core provided compelling evidence of the nature of climate and of climate feedbacks over the past 420 000 years marine records suggest that the amplitude of climate variability was smaller before that time but such records are often poorly resolved moreover it is not possible to infer the abundance of greenhouse gases in the atmosphere from marine records here we report the recovery of a deep ice core from dome c antarctica that provides a climate record for the past 740 000 years for the four most recent glacial cycles the data agree well with the record from vostok the earlier period between 740 000 and 430 000 years ago was characterized by less pronounced warmth in interglacial periods in antarctica but a higher proportion of each cycle was spent in the warm mode the transition from glacial to interglacial conditions about 430 000 years ago termination v resembles the transition into the present interglacial period in terms of the magnitude of change in temperatures and greenhouse gases but there are significant differences in the patterns of change the interglacial stage following termination v was exceptionally long 28 000 years compared to for example the 12 000 years recorded so far in the present interglacial period given the similarities between this earlier warm period and today our results may imply that without human intervention a climate similar to the present one would extend well into the future

sea level and climate changes during ois 5e in the western mediterranean palaeontological geomorphological and sedimentological data supported by isotopic dating on oxygen isotopic stage ois 5e deposits from the spanish mediterranean coast are interpreted with the aim of reconstructing climatic instability in the northern hemisphere data point to marked climatic instability during the last interglacial ois 5e with a change in meteorological conditions and consequently in the sedimentary environment the oolitic facies generated during the first part of ois 5e ca 135 kyr shift into reddish conglomeratic facies during the second part ca 117 kyr sea surface temperature sst and salinity are interpreted mainly on the basis of warm senegalese fauna which show chronological and spatial differential distribution throughout the western mediterranean present hydrological and meteorological conditions are used also as modern analogues to reconstruct climatic variability throughout the last interglacial and this variability is interpreted within the wider framework of the north atlantic record all the available data indicate an increase in storminess induced by an increase in the influence of northwesterlies a slight drop of sst in the northern western mediterranean and an important change in meteorological conditions at the end of ois 5e 117 kyr these changes correlate well with the decrease in summer insolation and with the climatic instability recorded in north atlantic high latitudes

the late palaeocene early eocene and toarcian early jurassic carbon isotope excursions a comparison of their time scales associated environmental changes causes and consequences although the earth9s environment is constantly changing there have been a few unusual episodes over the last c 200 ma when change was extreme in terms of its rapidity severity long lasting consequences and unpredictability the geochemical and biotic records for two of these episodes the palaeocene eocene thermal maximum and the toarcian oceanic anoxic event early jurassic possess many significant similarities each event was associated with a major carbon isotope excursion significant levels of biotic extinctions severe global warming an enhanced hydrological cycle and evidence for widespread seawater anoxia both carbon isotope excursions can be subdivided into distinct stages with broadly similar characteristics and durations based on a detailed comparison the palaeocene eocene thermal maximum may have been an incipient oceanic anoxic event the geochemical and biotic changes during these two events are most readily explained by the abrupt large scale dissociation of methane hydrate that followed a period of more gradual environmental change linked to the emplacement of a large igneous province carbon release rates at those times were of the same order of magnitude as the current anthropogenic release rate of carbon to the atmosphere indicating that ancient events such as these may usefully serve as analogues for present day environmental change

a stratigraphical basis for the anthropocene recognition of intimate feedback mechanisms linking changes across the atmosphere biosphere geosphere and hydrosphere demonstrates the pervasive nature of humankind s influence perhaps to the point that we have fashioned a new geological epoch the anthropocene to what extent will these changes be evident as long lasting signatures in the geological record to establish the anthropocene as a formal chronostratigraphical unit it is necessary to consider a spectrum of indicators of anthropogenically induced environmental change and to determine how these show as stratigraphic signals that can be used to characterize an anthropocene unit and to recognize its base it is important to consider these signals against a context of holocene and earlier stratigraphic patterns here we review the parameters used by stratigraphers to identify chronostratigraphical units and how these could apply to the definition of the anthropocene the onset of the range of signatures is diachronous although many show maximum signatures which post date1945 leading to the suggestion that this date may be a suitable age for the start of the anthropocene

can an anthropocene series be defined and recognized we consider the anthropocene as a physical chronostratigraphic unit across terrestrial and marine sedimentary facies from both a present and a far future perspective provisionally using an approximately 1950 ce base that approximates with the great acceleration worldwide sedimentary incorporation of a bomb derived radionuclides and light nitrogen isotopes linked to the growth in fertilizer use and other markers more or less effective recognition of such a unit today with annual decadal resolution is facies dependent and variably compromised by the disturbance of stratigraphic superposition that commonly occurs at geologically brief temporal scales and that particularly affects soils deep marine deposits and the pre 1950 parts of current urban areas the anthropocene thus more than any other geological time unit is locally affected by such blurring of its chronostratigraphic boundary with holocene strata nevertheless clearly separable representatives of an anthropocene series may be found in lakes land ice certain river delta systems in the widespread dredged parts of shallow marine systems on continental shelves and slopes and in those parts of deep water systems where human rafted debris is common from a far future perspective the boundary is likely to appear geologically instantaneous and stratigraphically significant

diagenesis and porosity development in the first eocene reservoir at the giant wafra field partitioned zone saudi arabia and kuwait the first eocene reservoir at the wafra field produces heavy oil from very porous dolomites at depths of 300 to 400 m in the paleocene eocene umm er radhuma formation porosity is commonly 30 50 permeability is commonly 100 2000 md and those reservoir characteristics were determined largely by diagenesis early diagenesis is dominated by dolomitization dissolution associated with dolomitization and precipitation of sulfates petrographic and stable isotopic characteristics support dolomitization and sulfate precipitation in evaporated refluxing seawater during shallow burial the highest permeabilities occur in subtidal facies low permeability tidal flat facies stratify the reservoir heavy oil preferentially filled high permeability dolomites whereas low permeability tidal flat facies are commonly filled with water because their pore throats are too small to allow migration of viscous oil into the rock this reservoir s very high porosity is probably related to its shallow burial and early oil emplacement late stage diagenesis is dominated by bacterial sulfate reduction bsr that caused dissolution of sulfate nodules calcite cementation sulfur precipitation and oil biodegradation the bsr is indicated by very low compositions of calcite cements to peedee belemnite standard which require an organic carbon source probably oil the oxygen isotopic compositions of the calcites support precipitation from formation waters similar to those in the reservoir now the bsr probably started during initial oil emplacement and continues to the present the bsr was heterogeneous resulting in produced oils with gravities of 14 21 api even heavier oils are present that could not flow during primary production primary production was likely greatest in areas and intervals with lighter less viscous oil

humans as geologic agents a deep time perspective humans move increasingly large amounts of rock and sediment during various construction activities and mean rates of cropland soil loss may exceed rates of formation by up to an order of magnitude but appreciating the actual importance of humans as agents of global erosion necessitates knowledge of prehistoric denudation rates imposed on land surfaces solely by natural processes amounts of weathering debris that compose continental and oceanic sedimentary rocks provide one such source of information and indicate that mean denudation over the past half billion years of earth history has lowered continental surfaces by a few tens of meters per million years in comparison construction and agricultural activities currently result in the transport of enough sediment and rock to lower all ice free continental surfaces by a few hundred meters per million years humans are now an order of magnitude more important at moving sediment than the sum of all other natural processes operating on the surface of the planet relationships between temporal trends in land use and global population indicate that humans became the prime agents of erosion sometime during the latter part of the first millennium a d

palaeontological evidence for defining the anthropocene palaeontologyformedthebasisfordefiningmostofthegeologicaleras periods epochs and ages that are commonly recognized by the same token the anthropocene can be defined by diverse palaeontological criteria in accordance with commonly accepted biostratigraphic practice the most useful anthropocene biostratigraphic zones will be assemblage and abundance zones based on mixes of native and non native species in both the marine and terrestrial realms although lineage zones based on evolution of crop plants may also have utility also useful are human pro duced trace fossils which have resulted in prominent biohorizons that can mark the onset of the anthropocene especially the paved road system widespread through terrestrial regions and microplastics ubiquitous in near shore and deep water marine sediments most of these palaeon tological criteria support placing the holocene anthropocene boundary near 1950 continua tion of current extinction rates would produce an extinction biohorizon on the scale of the big five mass extinctions within a few centuries but enhanced conservation measures could prevent making mass extinction an anthropocene signature a grand challenge for palaeontologists now is to define anthropocene biostratigraphic zones rigorously not only as a necessary precursor to formalizing the epoch but also to more fully understand how humans have restructured the biosphere

assessing the anthropocene with geochemical methods anthropogenic chemical contamination is one of the most evident signals of human influence on the environment the large amounts of industrially produced pollutants that have been introduced over decades into air soil and water have caused modifications to natural elemental cycling anthropogenic contamination usually leads to enrichment in many elements particularly in industrial areas thus certain elements and their isotopes can be used as geochemical tracers of anthropogenic impact some human induced changes in the environment may be regarded as a secondary effect of pollution such as acidification which causes increased geochemical mobility of several trace elements in surficial deposits methods used by geochemists to assess the scale of anthropogenic influence on the environment include calculations of anthropogenic influence on the environment via enrichment and contamination factors geoaccumulation index and pollution load index the use of geochemical background levels for delineating between natural and anthropogenic pollution is important a historical perspective of anthropogenic contamination allied with isotopic and geochemical signatures in dated sediment cores may be applied to help define the anthropocene human influence on the environment has been complex encompassing different environmental compartments air water soil and scales of changes local regional global the earth is a dynamic system and geochemical dynamics are best illustrated by consideration of element cycling although anthropogenic pollution sources have contributed to chemical changes in the atmosphere hydrosphere pedosphere and biosphere their impact on the total environment is best preserved in sediments which are often referred to as archives of contamination choi wania 2011 significant evidence of a distinctive anthropocene signal can be found in recent sedimentary deposits that have been impacted by anthropogenic activity and dated sediment cores can be used to reconstruct the chronology of contamination buckley et al 1995 in assessing the anthropocene it is important to quantify the human influence on the environment the results of this influence recorded in sediments can be evaluated using different approaches and criteria depending on the nature of the signal mechanical biological or chemical fig 1 zalasiewicz et al 2011a b price et al 2011 vane et al 2011 schrag 2012 geochemical methodology may help discriminate natural and anthropogenic sources of a given substance in the environment some of the methods and concepts e g anomaly background concentrations geochemical calculations and geochemical tracers traditionally used in geochemical exploration and further adapted to the needs of environmental geochemistry have found application in the study of anthropogenic contamination reimann de caritat 2005 reimann et al 2005 galuszka 2007 galuszka migaszewski 2011 these methods may be extended in assessment of the anthropocene anthropogenic anomalies and geochemical background concept geochemical anomalies can be defined as abnormal concentrations of elements in earth materials compared with background levels allaby allaby 1999 anomalous concentrations of elements are both of natural origin e g via oreforming processes weathering of ore bodies or mineralized rock formations sorption by mineral phases volcanic and hydrothermal activity and of anthropogenic origin mcqueen 2009 of the different types of geochemical anomalies fig 2 the positive anthropogenic anomalies of regional scale may provide a useful marker for the anthropocene selinus esbensen 1995 identification of geochemical anomalies requires knowledge of the normal or average distribution of elements in the environment which is usually referred to as a geochemical background lower and upper limits of the geochemical background from waters c n zalasiewicz j a williams m ellis m a snelling a m eds a stratigraphical basis for the anthropocene geological society london special publications 395 http dx doi org 10 1144 sp395 5 the geological society of london 2013 publishing disclaimer www geolsoc org uk pub ethics range are considered thresholds of negative depletion in an element and positive enrichment in an element anomalies fig 3 historically the search for positive anomalies has been essential to mineral exploration and in the 1960s geochemists established several methodologies for separating anomalies from the geochemical background hawkes webb 1962 miesch 1967 many fig 1 types of human induced changes their possible effects and sedimentary record fig 2 systematics of geochemical anomalies a ga uszka et al

on the history of humans as geomorphic agents the human population has been increasing exponentially simultaneously as digging sticks and antlers have given way to wooden plows iron spades steam shovels and today s huge excavators our ability and motivation to modify the landscape by moving earth in construction and mining activities have also increased dramatically as a consequence we have now become arguably the premier geomorphic agent sculpting the landscape and the rate at which we are moving earth is increasing exponentially as hunter gatherer cultures were replaced by agrarian societies to feed this expanding population erosion from agricultural fields also until recently increased steadily this constitutes an unintended additional human impact on the landscape

metrics for quantifying anthropogenic impacts on geomorphology road networks this work tests the capability of a recently published topographic index the slope local length of auto correlation sllac to portrait and delineate anthropogenic geomorphologies the patterns of the anthropogenic pressure are defined considering the road network density and the urban complexity index uci first the research investigates the changes in the sllac in two derived parameters average sllac and the sllac surface peak curvature spc per km2 connected to the increasing of the anthropogenic structures next natural and anthropogenic landscapes are clustered and classified the results show that there is a direct correlation between the road network density and the uci and the mean sllac per km2 however the spc is inversely correlated with the anthropogenic pressure network density and urban complexity this shows that the surface morphology slope of regions presenting anthropogenic structures tends to be well organized low spc and in general self similar at a long distance higher average sllac the results of the clustering approach show that the procedure can correctly depict anthropogenic landscapes having a road network density greater than about 3 km km2 also in areas covered by vegetation this latter result is promising for the use of such a procedure in regions that cannot be seen directly from orthophotos or satellite images the proposed method can actively capture the alteration produced by road networks on surface morphology identifying different signatures of urban development exploration and densification networks that are responsible for increasing the local density of the network and expanding the network into new areas respectively the effects of this alteration on surface processes could be significant for future research creating new questions about differences due to human or landscape forcing on earth surface processes copyright 2015 john wiley sons ltd

pore types and pore size distributions across thermal maturity eagle ford formation southern texas pore types pore size and pore abundance vary systematically across thermal maturity in the eagle ford formation maverick basin southern texas scanning electron imaging of 20 samples from four wells is used to assess the complex response of pores to chemical and mechanical processes entailing both destruction of primary porosity and generation of secondary pores primary mineral associated pores are destroyed by compaction cementation and infill of secondary organic matter whereas secondary pores are generated within organic matter om destruction of primary pores during early burial to 0 5 occurs by compaction of ductile detrital om and clays and to a lesser degree as a result of cementation and infill of secondary om larger pores are associated with coccolith debris the dominant om is spatially isolated detrital om stringers porosity is volumetrically dominated average 6 2 by relatively large mostly interparticle mineral associated pores median size 51 6 nm 0 000002 in detection limit near 3 4 nm 0 00000012 0 00000015 in at low maturity porosity and pore size correlate directly with calcite abundance and inversely with om volumes at higher maturity further destruction of primary pores occurs through cementation secondary om infill and greater compaction mineral associated pores are present at high maturity 1 2 1 3 but are smaller median size 30 2 nm 0 0000011 in and less abundant average of 2 5 than at low maturity a large portion of om within high maturity samples is diagenetic in origin and has pervaded into primary pore space coating cement crystals and filling intraparticle pores substantial mineral associated porosity is locally present in samples where incursion of primary pore space by secondary om has not occurred abundant secondary porosity is generated as om matures into the wet gas window porosity in most high maturity samples is volumetrically dominated average of 1 3 by smaller om hosted pores median size 13 2 nm 0 00000051 in

reef drowning during the last deglaciation evidence for catastrophic sea level rise and ice sheet collapse elevations and ages of drowned acropora palmata reefs from the caribbean atlantic region document three catastrophic metre scale sea level rise events during the last deglaciation these catastrophic rises were synchronous with 1 collapse of the laurentide and antarctic ice sheets 2 dramatic reorganization of ocean atmosphere circulation and 3 releases of huge volumes of subglacial and proglacial meltwater this correlation suggests that release of stored meltwater periodically destabilized ice sheets causing them to collapse and send huge fleets of icebergs into the atlantic massive inputs of ice not only produced catastrophic sea level rise drowning reefs and destabilizing other ice sheets but also rapidly reduced the elevation of the laurentide ice sheet flipping atmospheric circulation patterns and forcing warm equatorial waters into the frigid north atlantic such dramatic evidence of catastrophic climate and sea level change during deglaciation has potentially disastrous implications for the future especially as the stability of remaining ice sheets such as in west antarctica is in question

diagenesis of a tight gas sand reservoir upper cretaceous mesaverde group piceance basin colorado abstract the upper cretaceous mesaverde group in the piceance basin western colorado contains thick sections of low porosity low permeability sandstones that are reservoirs for large accumulations of hydrocarbon gas the mesaverde sandstones are lithic arkoses and feldspathic litharenites containing quartz plagioclase variable k feldspar chert and volcanic rock fragments important diagenetic processes that have affected the sandstones include compaction dissolution of feldspar and or alteration to clay precipitation of carbonate and quartz cements precipitation of illite and alteration of detrital clays mixed layer illite smectite porosity is relatively constant a decrease in primary porosity downward is approximately balanced by an increase in secondary porosity with significant microporosity in authigenic and diagenetic clays k feldspar is almost completely absent below 5500 feet 1675 m fibrous illite is relatively abundant above this depth and variable in abundance below the k ar ages of the clays increase with depth from 40 m y at the top of the sampled section to 55 m y at the base indicating illitization of a precursor smectite at approximately the 100 c isotherm samples with abundant fibrous illite have relatively smaller age values mass balance calculations indicate that dissolution of k feldspar illitization of smectite and precipitation of fibrous illite were coupled these reactions suggest the transport of dissolved potassium upward hundreds of feet 100 300 m in the section possibly associated with water driven vertically by the migration of gas

dendrogeomorphic assessment and sediment transfer of natural vs mining induced debris flow activity in călimani mountains eastern carpathians romania abstract during the second half of the twentieth century in the central part of the c limani mountains the mining activities for sulfur rich ore extraction and processing produced significant landscape changes sediment transfers across the affected catchments started during the mining period and are still ongoing today more than two decades after the cessation of the mining activities in 1997 subsequently neither rehabilitation works nor erosion control measures were undertaken to stabilize the spoil heap deposits and natural reforestation also material consolidation was impeded by the highly unstable talus slopes moreover little is known about the frequency of the hydrogeomorphic processes responsible for sediment transfers and their consequences dendrogeomorphic investigations grain size analyses and topographic surveys were carried out to document the history of hydrogeomorphic activity the volume of material stored behind the retention dams and the rate of sediment accumulation tree ring analysis allowed us to reconstruct ten debris flow events in the natural environment as well as in mining disturbed environment for the period 1931 2017 and 1970 2017 respectively triggering of debris flows appears related to spring and summer precipitation originating from short duration convective systems or long lasting rainfalls in these remote mining areas the reconstructed frequency of debris flows return intervals of 8 1 and 4 7 years might be explained by the rainwater accumulation on the spoil heap platform and the availability of sediments which flow down the talus and then follow the stream channels to reach one of the sediment retention reservoirs 7 4 8 4 cm y 1

agro industrial alluvium in the swale catchment northern england as an event marker for the anthropocene foulds s a macklin m g brewer p a 2013 agro industrial alluvium in the swale catchment northern england as an event marker for the anthropocene the holocene 23 4 587 602

an assessment of lithostratigraphy for anthropogenic deposits the deliberate anthropogenic movement of reworked natural and novel manufactured materials represents a novel sedimentary environment associated with mining waste disposal construction and urbanization anthropogenic deposits display distinctive engineering and environmental properties and can be of archaeological importance this paper shows that temporal changes in the scale and lithological character of anthropogenic deposits may be indicative of the anthropocene however the stratigraphy of such deposits is not readily described by existing classification schemes which do not differentiate separate phases or lithologically distinct deposits beyond a local scale lithostratigraphy is a scalable hierarchical classification used to distinguish successive and lithologically distinct natural deposits many natural and anthropogenic deposits exhibit common characteristics they typically conform to the law or principle of superposition and exhibit lithological distinction the lithostratigraphical classification of surficial anthropogenic deposits may be effective although defined units may be significantly thinner and far less continuous than those defined for natural deposits further challenges include the designation of stratotypes accommodating the highly diachronous nature of anthropogenic deposits and the common presence of disconformities international lithostratigraphical guidelines would require significant modification before being effective for the classification of anthropogenic deposits a practical alternative may be to establish an anthrostratigraphical approach or anthrostratigraphy

comparison of diagenetic characteristics and pore evolution in outcrops and cores of tight sandstone reservoirs in the triassic yanchang formation the ordos basin china the sedimentary and diagenetic control on tight sandstone reservoir quality is a key focus of hydrocarbon exploration this paper compares reservoir characteristics such as diagenetic processes pore types and porosity evolution of cores and outcrops of the yanchang formation the ordos basin northwestern china to identify diagenetic trends and processes responsible for improving reservoir quality and to develop a model for identifying reservoir sweet spots in tight sandstone formations samples of the yanchang formation sandstone are taken from wells and adjacent outcrops in the ordos basin no significant differences were found in porosity destructive diagenesis such as compaction and cementation between the core and outcrop samples however the effects of dissolution are far more pronounced in cores than in the outcrop resulting in a higher core sample porosity high density sampling of the outcrop revealed that the reservoir sweet spot model is controlled by sedimentation whereas three distinct vertical diagenetic zones were identified in adjacent wells a comprehensive analysis of cores and outcrop samples shows that both areas experienced similar sedimentation and early diagenetic patterns however the diagenetic processes experienced by core and outcrop sandstones diverged during the later part of burial and uplift with dissolution being responsible for the contrasting reservoir porosities between core and outcrop

the late ordovician mass extinction abstract near the end of the late ordovician in the first of five mass extinctions in the phanerozoic about 85 of marine species died the cause was a brief glacial interval that produced two pulses of extinction the first pulse was at the beginning of the glaciation when sea level decline drained epicontinental seaways produced a harsh climate in low and mid latitudes and initiated active deep oceanic currents that aerated the deep oceans and brought nutrients and possibly toxic material up from oceanic depths following that initial pulse of extinction surviving faunas adapted to the new ecologic setting the glaciation ended suddenly and as sea level rose the climate moderated and oceanic circulation stagnated another pulse of extinction occurred the second extinction marked the end of a long interval of ecologic stasis an ecologic evolutionary unit recovery from the event took several million years but the resulting fauna had ecologic patterns similar to the fauna that had become e

proposal to add anthrostratigraphic and technostratigraphic units to the stratigraphic code for classification of anthropogenic holocene deposits anthropogenic surficial deposits are formed from holocene and older deposits that have been so modified by human activity that their original form is unrecognizable because their characteristics are fundamentally different from those of natural origin the creation of special stratigraphic categories seems justified two new material categories are proposed for the stratigraphic classification of anthropogenic deposits an anthrostratigraphic unit asu is defined as a stratiform or irregularly shaped body of anthropogenic origin in the sedimentary record distinguished and delineated on the basis of lithologic characteristics and or bounding disconformities an anthropogenic origin is indicated if the deposit 1 lies beneath an anthropogenic landform 2 contains artifacts 3 shows evidence of artificial mixing or other human disturbance and or 4 was imported from offsite and is allochthonous the basic asu is the anthrostratum defined as a mostly stratiform body of artificially mixed earth rock

a futurist perspective on the anthropocene an important feature of the ongoing debate about the acceptance of the anthropocene as a formal chronostratigraphic unit with the same rank as the holocene epoch has been either the existence or

the use of bomb spike calibration and high precision ams 14c analyses to date salt marsh sediments deposited during the past three centuries abstract a combination of bomb spike calibration and conventional calibration of ams 14c dating has been used to determine a detailed age depth model for a 1 m sediment section collected from a salt marsh in poole harbour southern england these data were compared with the chronology obtained from 210pb analysis and 137cs age markers we report post bomb values of over 1 46 f14c 146 modern 14c and both the rising and falling limbs of the atmospheric bomb spike are identified five pre bomb samples were analysed using multi target high precision 2 ams analysis and after the replicates were combined the one sigma uncertainty was as low as 9 14c yr on some ages these data and an additional three normal precision pre bomb 14c samples were calibrated using calib 5 0 and the chronology constrained using the prior knowledge of independent age markers obtained from the analysis of pollen and spheroidal carbonaceous particle scps no agreement was found between the 14c bomb spike dates and the crs 210pb chronology modelled for this sequence in addition poor agreement was found between the signal of the 1960s weapons test fallout indicated by the 14c bomb spike dates and the timing suggested by the 137cs data this disagreement is attributed to the influence of the local discharge of 137cs from the former ukaea site at winfrith we use our new chronology to confirm the existence of an acceleration in sedimentation rates in poole harbour during the last 100 yr previously reported for this site by long et al long a j scaife r g edwards r j 1999 pine pollen in intertidal sediments from poole harbour uk implications for late holocene sediment accretion rates and sea level rise quaternary international 55 3 16 and conclude that bomb spike 14c calibration dating may offer a more robust alternative to the use of 210pb chronologies for dating sediment deposition in salt marsh environments in addition we demonstrate how the use of high precision ams analysis has the potential for reducing some of the uncertainties involved in the high resolution dating of recent salt marsh sediments

graptolites in british stratigraphy 697 taxa of planktonic graptolites are recorded and their stratigraphical ranges are given through 60 biozones and subzones in the ordovician and silurian strata of england wales and scotland in the first such stratigraphical compilation for great britain since the synthesis of elles wood 1901 1918

stratigraphic expressions of the holocene anthropocene transition revealed in sediments from remote lakes stratigraphic boundaries are ideally defined by distinct lithological geochemical and palaeobiological signatures to which a chronological framework can be applied we present a range of observations that illustrate how the holocene anthropocene transition meets these criteria in its expression in sediments from remote arctic and alpine lakes removed from direct catchment scale anthropogenic influences in glaciated lake basins the retreat of glaciers commonly leads to lithological successions from proglacial clastic sedimentation to non glacial organic deposition sediments from the majority of lakes record marked depletions in the nitrogen stable isotopic composition of sediment organic matter reflecting anthropogenic influences on the global nitrogen cycle in all cases siliceous microfossil assemblages diatoms and chrysophytes change markedly and directionally with regional nuances these stratigraphic fingerprints begin to appear in the sediment record after ad 1850 but accelerate in pulses between ad 1950 and 1970 and again after ad 1980 our review indicates that recent environmental changes associated with humankind s dominance of key global biogeochemical cycles are sufficiently pervasive to be imprinted on the sediment record of remote lakes moreover these changes are of sufficient magnitude to conclude that the holocene has effectively ended and that the concept of anthropocene more aptly describes current planetary dynamics the synthesis of these observations pertains directly to ongoing discussions concerning the eventual formalization of a new stratigraphic boundary

osmium isotope evidence for the regulation of atmospheric co2 by continental weathering the long term stability of earth9s climate throughout the phanerozoic stands in marked contrast to the dramatic fluctuations that have taken place on time scales as short as a few years reflecting the high efficiency of longer term climate regulation through negative feedbacks a fundamental mechanism is thought to involve control of co 2 in the ocean atmosphere system through continental weathering although unambiguous high resolution data supporting this hypothesis have hitherto not been available organic rich mud rocks from yorkshire england which were deposited during the toarcian oceanic anoxic event ca 181 ma early jurassic contain evidence of an exceptionally large excursion in the 187 os 188 os ratio of contemporaneous seawater from 0 4 to 1 0 the most likely explanation for this excursion is that it resulted from a transient increase in global continental weathering rates of 400 800 the os isotope excursion coincided with a well documented global 13 c excursion of 6 that affected all the major biospheric reservoirs of the time higher mean global temperatures caused global chemical weathering rates to increase substantially while in turn chemical weathering was very effective in reducing the elevated levels of atmospheric co 2 and the high temperatures to preexcursion levels

the onset of the palaeoanthropocene in iceland changes in complex natural systems this study was financially supported by the carnegie trust for the universities of scotland the national science foundation of america through grant 1202692 comparative island ecodynamics in the north atlantic and grant 1249313 tephra layers and early warning signals for critical transitions and the leverhulme trust study abroad fellowship to ajd

role of debris flows in long term landscape denudation in the central appalachians of virginia four major storms that triggered debris flows in the virginia west virginia appalachians provide new insights into the role of high magnitude low frequency floods in longterm denudation and landscape evolution in mountainous terrain storm denudation in the blue ridge mountain drainage basins is approximately an order of magnitude greater compared to basins located in the mountains of the valley and ridge province this difference is probably the result of higher storm rainfall from the blue ridge storms radiocarbon dating of debris flow deposits in the blue ridge indicates a debris flow return interval of not more than 2 4 k y in mountainous river basins this finding combined with measurements of basin denudation suggests that approximately half of the long term denudation from mechanical load occurs episodically by debris flow processes although floods of moderate magnitude are largely responsible for mobilizing sediment in lowgradient streams our data suggest that high magnitude low frequency events are the most significant component in delivering coarse grained regolith from mountainous hollows and channels to the lowland floodplains

the geomorphology of the anthropocene emergence status and implications the anthropocene is proposed as a new interval of geological time in which human influence on earth and its geological record dominates over natural processes a major challenge in demarcating the anthropocene is that the balance between human influenced and natural processes varies over spatial and temporal scales owing to the inherent variability of both human activities as associated with culture and modes of development and natural drivers e g tectonic activity and sea level variation against this backdrop we consider how geomorphology might contribute towards the anthropocene debate focussing on human impact on aeolian fluvial cryospheric and coastal process domains and how evidence of this impact is preserved in landforms and sedimentary records we also consider the evidence for an explicitly anthropogenic geomorphology that includes artificial slopes and other human created landforms this provides the basis for discussing the theoretical and practical contributions that geomorphology can make to defining an anthropocene stratigraphy it is clear that the relevance of the anthropocene concept varies considerably amongst different branches of geomorphology depending on the history of human actions in different process domains for example evidence of human dominance is more widespread in fluvial and coastal records than in aeolian and cryospheric records so geomorphologically the anthropocene would inevitably comprise a highly diachronous lower boundary even to identify this lower boundary research would need to focus on the disambiguation of human effects on geomorphological and sedimentological signatures this would require robust data derived from a combination of modelling and new empirical work rather than an arbitrary war of possible boundaries associated with convenient but disputed golden spikes rather than being drawn into stratigraphical debates the primary concern of geomorphology should be with the investigation of processes and landform development so providing the underpinning science for the study of this time of critical geological transition

the humanized earth system hes a number of informal terms e g anthropocene anthropozoic psychozoic noozoic and technogene have been used to designate the rock unit and time interval where the impact of collective human action on the earth system is clearly recognizable called here the humanized earth system hes presently anthropocene is the most commonly used and the international commission on stratigraphy is considering its acceptance as a formal stratigraphic unit despite their informal character all of these terms contain suffixes i e cene zoic or gene that define formal chronostratigraphic geochronologic c g units e g series epoch erathem era and system period which is misleading in addition the use of these terms involves unsupported evolutionary assumptions and may lead to conflicting stratigraphic settings therefore it is recommended that these terms are avoided until there is sufficient scientific support to unequivocally define its c g rank which is not expected to occur in the near future

an evolving research agenda for human coastal systems within the broad discourses of environmental change sustainability science and anthropogenic earth surface systems a focused body of work involves the coupled economic and physical dynamics of developed shorelines rapid rates of change in coastal environments from wetlands and deltas to inlets and dune systems help researchers recognize observe and investigate coupling in natural non human morphodynamics and biomorphodynamics this same intrinsic quality of fast paced change also makes developed coastal zones exemplars of observable coupling between physical processes and human activities in many coastal communities beach erosion is a natural hazard with economic costs that coastal management counters through a variety of mitigation strategies including beach replenishment groynes revetments and seawalls as cycles of erosion and mitigation iterate coastline change and economically driven interventions become mutually linked emergent dynamics of two way economic physical coupling is a recent research discovery having established a strong theoretical basis research into coupled human coastal systems has passed its early proof of concept phase this paper frames three major challenges that need resolving in order to advance theoretical and empirical treatments of human coastal systems 1 codifying salient individual and social behaviors of decision making in ways that capture societal actions across a range of scales thus engaging economics social science and policy disciplines 2 quantifying anthropogenic effects on alongshore and cross shore sediment pathways and long term landscape evolution in coastal zones through time including direct measurement of cumulative changes to sediment cells resulting from coastal development and management practices e g construction of buildings and artificial dunes bulldozer removal of overwash after major storms and 3 reciprocal knowledge and data exchange between researchers in coastal morphodynamics and practitioners of coastal management future research into human coastal systems can benefit from decades of interdisciplinary work on the complex dynamics of common pool resources from computational efficiency and new techniques in numerical modeling and from the growing catalog of high resolution geospatial data for natural and developed coastlines around the world

classification of artificial man made ground abstract the legacy inherited from anthropogenic processes needs to be addressed in order to provide reliable and up to date ground information relevant to development and regeneration in the urban environment the legacy includes voids as well as anthropogenic deposits artificial ground their characteristics derive from former quarrying and mining activities industrial processes creating derelict ground variably consolidated made ground and contaminated groundwater and soils all need to be systematically assessed to inform the planning process and provide the basis for engineering solutions site specific investigation needs to be conducted on the back of good quality geoscientific data this comes from field survey remotely sensed data interpretation historical maps soil geochemical sampling and geotechnical investigation three dimensional and in the future four dimensional characterization of superficial deposits is required to reach an understanding of the potential spatial lithological variability of artificial ground and the geometry of important surfaces i e the boundary conditions the classification scheme for artificial ground outlined in this paper and adopted by the british geological survey will help in achieving this understanding

siltation of river influenced coastal environments respective impact of late holocene land use and high frequency climate changes abstract the aim of this study is to unravel the respective influence of land use and high frequency climate changes on the siltation of a river influenced coastal environment an 8 4 m long sediment core was recovered in the pertuis charentais western france an accurate 14 c bayesian age model was developed to perform a depth to time conversion of high resolution sedimentological data obtained on the core forest loss and precipitation changes that occurred on the related catchments were reconstructed from data gathered in the literature a sharp increase in winter rainfall 1700 1750 ad intensified erosion of catchments previously sensitised by increased forest loss 1640 1710 ad which resulted in a massive supply of silt to the coast from ca 1775 ad onwards a review of articles reporting similar mud layers is also proposed depending on their age some major phases of mankind migration history could be traced back which confirms the predominant influence of human activities on the siltation of river influenced coastal environments we therefore propose to group these mud layers into the anthropogenic system tracts in reference to widely used sequence stratigraphy nomenclature and we suggest that it might help to identify a holocene to anthropocene stratigraphic boundary in coastal areas

calcareous plankton evolution and the paleocene eocene thermal maximum event new evidence from tanzania the biotic response of calcareous microplankton at the paleocene eocene thermal maximum petm climate event principally comprised poleward migrations the appearance of excursion taxa and elevated turnover in calcareous nannoplankton here we examine whether this relatively muted evolutionary signal may be due to the quality of the stratigraphic and fossil record by analysing exceptionally well preserved microfossils from an expanded hemipelagic petm section in southern tanzania tdp site 14 both nannofossils and planktonic foraminifera show major abundance declines at the onset of the petm that are not explained by dilution or dissolution the petm onset is also marked by the extinction of eight nannofossil species possibly as many as 12 and the intra petm assemblages are quite distinct from background and dominated by coccolithus including the excursion taxon c bownii this biotic response is not clearly biased in favour of particular ecological groups although the nannofossil excursion taxa were all warm water favouring and there was a net diversity loss within cool water favouring eutrophic groups a shift from toweius to coccolithus dominated assemblages is suggestive of increased oligotrophy although the presence of abundant gladiolithus indicates upper photic zone oligotrophy throughout the time interval represented by the tdp site 14 section the significant plankton assemblage shifts diversity decline and possible reduction of calcareous plankton production and or export suggest the rapid onset of highly disruptive environmental change at the petm onset this change must have included rapid temperature increase and heat stress may have played a role in shaping the petm assemblage compositions causing a limited number of extinctions and favouring taxa from warmer areas of the groups ecological range however the muted evolutionary response in these plankton groups indicates that they were highly resilient to this environmental change and through adaptation to the new conditions e g the excursion taxa but probably principally through range shifts i e migration or simply the ability to acclimatize the vast majority of the biodiversity survived and thrived again once conditions returned to normal

formal subdivision of the holocene series epoch a discussion paper by a working group of intimate integration of ice core marine and terrestrial records and the subcommission on quaternary stratigraphy international commission on stratigraphy this discussion paper by a working group of intimate integration of ice core marine and terrestrial records and the subcommision on quaternary stratigraphy sqs of the international commission on stratigraphy ics considers the prospects for a formal subdivision of the holocene series epoch although previous attempts to subdivide the holocene have proved inconclusive recent developments in quaternary stratigraphy notably the definition of the pleistocene holocene boundary and the emergence of formal subdivisions of the pleistocene series epoch mean that it may be timely to revisit this matter the quaternary literature reveals a widespread but variable informal usage of a tripartite division of the holocene early middle or mid and late and we argue that this de facto subdivision should now be formalized to ensure consistency in stratigraphic terminology we propose an early middle holocene boundary at 8200 a bp and a middle late holocene boundary at 4200 a bp each of which is linked to a global stratotype section and point gssp should the proposal find a broad measure of support from the quaternary community a submission will be made to the international union of geological sciences iugs via the sqs and the ics for formal ratification of this subdivision of the holocene series epoch copyright 2012 john wiley sons ltd

fate of fossil fuel co2 in geologic time 1 a model of the ocean and seafloor carbon cycle is subjected to injection of new co2 pulses of varying sizes to estimate the resident atmospheric fraction over the coming 100 kyr the model is used to separate the processes of air sea equilibrium an ocean temperature feedback caco3 compensation and silicate weathering on the residual anthropogenic pco2 in the atmosphere at 1 10 and 100 kyr the mean lifetime of anthropogenic co2 is dominated by the long tail resulting in a range of 30 35 kyr the long lifetime of fossil fuel carbon release implies that the anthropogenic climate perturbation may have time to interact with ice sheets methane clathrate deposits and glacial interglacial climate dynamics

middle and upper ordovician carbon isotope chemostratigraphy in baltoscandia a correlation standard and clues to environmental history abstract the baltoscandian epeiric sea was characterised by relatively slow but continuous carbonate deposition from the middle ordovician up to the silurian relatively good preservation of ordovician and silurian carbonate rocks in baltoscandia makes this region unique for chemostratigraphical and palaeoenvironmental studies previous palaeozoic carbon isotope studies have revealed isotopic events in different lithologies over the baltoscandian palaeobasin and some of them on different palaeocontinents we propose a composite carbon isotope curve for the baltoscandian region a new subdivision of the middle and upper ordovician succession into seventeen chemostratigraphic zones and an improved nomenclature of isotopic excursions based on analyses of 13 c carb data from 25 drillcore and outcrop sections of estonia latvia and sweden the composite carbon isotope curve is compared with biostratigraphical data on conodont and chitinozoan distribution the katian hirnantian interval with highly fluctuating isotopic values shows climatic cyclicity of about two million years in baltoscandia no abrupt changes occur in the dapingian sandbian part of the baltoscandian isotope curve but the mid darriwilian excursion nearly coincides with the onset of cooler temperatures similar to modern like equatorial sea surface temperatures and related global biodiversification increase suggesting a climatic background for this event

human topographic signatures and derived geomorphic processes across landscapes abstract the earth s surface morphology in an abiotic context is a consequence of major forcings such as tectonic uplift erosion sediment transport and climate recently however it has become essential for the geomorphological community to also take into account biota as a geomorphological agent that has a role in shaping the landscape even if at a different scale and magnitude from that of geology although the modern literature is flourishing on the impacts of vegetation on geomorphic processes the study of anthropogenic pressures on geomorphology is still in its early stages topography emerges as a result of natural driving forces but some human activities such as mining agricultural practices and the construction of road networks directly or indirectly move large quantities of soil which leave clear topographic signatures embedded on the earth s morphology these signatures can cause drastic changes to the geomorphological organization of the landscape with direct consequences on earth surface processes this review provides an overview of the recent literature on the role of humans as a geological agent in shaping the morphology of the landscape we explore different contexts that are significantly characterized by anthropogenic topographic signatures landscapes affected by mining activities road networks and agricultural practices we underline the main characteristics of those landscapes and the implications of human impacts on earth surface processes the final section considers future challenges wherein we explore recent novelties and trials in the concept of anthropogenic geomorphology herein we focus on the role of high resolution topographic and remote sensing technologies the reconstruction or identification of artificial or anthropogenic topographies provides a mechanism for quantifying anthropogenic changes to landscape systems this study may allow an improved understanding and targeted mitigation of the processes driving geomorphic changes during anthropogenic development and help guide future research directions for development based watershed studies human society is deeply affecting the environment with consequences on the landscape therefore establishing improved management measures that consider the earth s rapidly changing systems is fundamental

formal subdivision of the quaternary system period present status and future directions abstract the quaternary system period and pleistocene series epoch were defined in 2009 by the global boundary stratotype section and point gssp for the gelasian stage age 2 58 ma which aligns with marine isotope stage mis 103 and approximates the gauss matuyama chron boundary contrary to earlier reports the vrica gssp 1 80 ma was repurposed in 2011 to define the calabrian stage effectively completing the lower pleistocene subseries subepoch the candidate for the middle pleistocene subseries and proposed chibanian stage gssp 774 ka is the chiba section japan it aligns with mis 19 and approximates the matuyama brunhes chron boundary 773 ka the upper pleistocene subseries with a base traditionally marked by the onset of the last interglacial is not yet defined by gssp the holocene series epoch was formally defined in 2008 by a gssp in the ngrip2 greenland ice core with an age of 11 700 yr b2k before 2000 ce and in 2018 was subdivided using climatic events at 8 2 and 4 2 ka into the greenlandian northgrippian and meghalayan stages ages and their corresponding lower early middle upper late subseries subepochs the northgrippian gssp 8236 yr b2k is defined in the ngrip1 greenland ice core and the meghalayan gssp 4250 yr b2k in a speleothem from meghalaya india this subdivision formally introduces the rank of subseries subepoch and incorporates by far the briefest of all stages into the geological time scale using ice cores and a speleothem for gssps is unique to the holocene the presently undefined term anthropocene is already used extensively and like holocene subdivisional terms its functionality will be enhanced by formal definition the anthropocene should not be confused with anthropogenic it reflects a tipping point in the earth system response to the marked intensification of human impacts not simply the fact of human impact the geological anthropocene as currently envisioned would start in the mid twentieth century holding the rank of series and terminating the holocene but not interfering with its subdivision other than to terminate the meghalayan stage

coral reefs may start dissolving when atmospheric co2 doubles 1 calcification rates in stony corals are expected to decline significantly in the near future due to ocean acidification in this study we provide a global estimate of the decline in calcification of coral reefs as a result of increase in sea surface temperature and partial pressure of co2 this estimate unlike previously reported estimates is based on an empirical rate law developed from field observations for gross community calcification as a function of aragonite degree of saturation arag sea surface temperature and live coral cover calcification rates were calculated for more than 9 000 reef locations using model values of arag and sea surface temperature at different levels of atmospheric co2 the maps we produced show that by the time atmospheric partial pressure of co2 will reach 560 ppm all coral reefs will cease to grow and start to dissolve

chemostratigraphic and lithostratigraphic signatures of the anthropocene in estuarine areas from the eastern cantabrian coast n spain abstract a range of chemostratigraphic and lithostratigraphic markers of human impacts can be recorded in four estuaries located in the eastern cantabrian coast northern spain metal enriched levels and stable pb isotopic ratios in dated sediment cores allowed the recognition of an ancient local episode of pb contamination associated with mining activities during roman times as well as the widespread fingerprint of the industrial revolution and the great acceleration of human pressure after the second world war micropalaeontological data variations in foraminiferal assemblages provided key information to identify agricultural soils in previously reclaimed and currently regenerated salt marshes whereas anthropogenic beachrocks offered an example of the incorporation of technofossils to the coastal sedimentary record

geology of mankind for the past three centuries the effects of humans on the global environment have escalated because of these anthro pogenic emissions of carbon dioxide global climate may depart significantly from natural behaviour for many millennia to come it seems appropriate to assign the term anthropocene to the present in many ways human dominated geological epoch supplementing the holocene the warm period of the past 10 12 millennia

microbiotic signatures of the anthropocene in marginal marine and freshwater palaeoenvironments the term anthropocene has been proposed to indicate a geological interval character ized by global anthropogenic environmental change this paper attempts to recognize a method by which the anthropocene can be defined micropalaeontologically in order to do this microfloras and microfaunas diatoms macrophytes dinoflagellate cysts foraminifera and ostracods from nearshore waters through to paralic and freshwater aquatic milieux are considered and biotic varia bility with an anthropogenic causation identified microbiotic change can be related to anthropo genically induced extinctions pollution related mutation environmentally influenced assemblage variability geochemistry of carapaces tests floral change related to lacustrine acidification faunal and floral correlation to industrial and agricultural signatures and introduction of exotic species via shipping the influence of humanity on a local scale can be recognized in assemblages as far back as 5000 years bp however widespread anthropogenic change took place in europe and america particularly in the nineteenth and twentieth centuries although in asia e g japan it cannot be observed prior to the twentieth century profound and global biotic change began in the mid twentieth century and if the anthropocene is to be defined in this way then the period 1940 1945 might encompass the biotic base of the interval

simplifying the stratigraphy of time we propose ending the distinction between the dual stratigraphic terminology of time rock units of chronostratigraphy and geologic time units of geochronology the long held but widely misunderstood distinction between these two essentially parallel time scales in stratigraphy has been rendered unnecessary by the widespread adoption of the global stratotype sections and points gssp golden spike principle in defining intervals of geologic time within rock strata we consider that the most appropriate name for this stratigraphic discipline is chronostratigraphy which would allow geochronology to revert to its mainstream and original meaning of numerical age dating this in turn makes the little used formal term geochronometry redundant the terms eonothem erathem system series and stage would become redundant in favor of eon era period epoch and disputably age our favored geologic time units may be qualified by early and late but not by lower and upper these suggested changes should simplify stratigraphic practice encompass both stratified and nonstratified rocks and help geologic understanding while retaining precision of meaning

relationships between stylolites and cementation in sandstone reservoirs examples from the north sea u k and east greenland abstract the reservoir potential of hydrocarbon sandstone reservoirs may be significantly reduced by compartmentation as a result of the development of stylolites a petrographic and fluid inclusion microthermometric study was performed on sandstones containing abundant stylolites from the buchan galley and scott fields in the outer moray firth offshore scotland and from a palaeo oil bearing sequence in east greenland the main objective of this study was to further constrain the temperatures and burial depths at which stylolitization occurs in sandstone reservoirs the sandstones containing abundant stylolites are also characterized by their highly cemented nature numerous occurrences of quartz overgrowths clearly truncated by sutured stylolites are evident in all of the samples fluid inclusion microthermometry reveals that quartz cementation which is interpreted to be coeval with stylolitization occurred at minimum temperatures of between 86 and 136 c basin modelling of the scott and galley fields indicates that quartz cementation and stylolite development formed at depths greater than 2 5 km which were attained during rapid tertiary burial the occurrence of hydrocarbon fluid inclusions within healed microfractures orientated at high angles to the stylolites suggests that these microfractures provided pathways for hydrocarbon migration in the highly cemented low permeability zones associated with highly stylolitized sandstones

the anthropocene is there a geomorphological case the anthropocene as used to describe the interval of recent earth history during which humans have had an overwhelming effect on the earth system is now being formally considered as a possible new geological epoch such a new geological time interval possibly equivalent to the pleistocene epoch requires both theoretical justification as well as empirical evidence preserved within the geological record since the geological record is driven by geomorphological processes that produce terrestrial and near shore stratigraphy geomorphology has to be an integral part of this consideration for this reason the british society for geomorphology bsg has inaugurated a fixed term working group to consider this issue and advise the society on how geomorphologists can engage with debates over the anthropocene this esex commentary sets out the initial case for the formalisation of the anthropocene and a priori considerations in the hope that it will stimulate debate amongst and involvement by the geomorphological community in what is a crucial issue for the discipline the working group is now considering the practical aspects of such a formalization including the relative magnitude problem the boundary problem and the spatial diachrony of anthropogenic geomorphology copyright 2013 john wiley sons ltd

quantitative analysis of land transformation in a holocene delta an example from the tama river lowland central japan abstract human activities such as the expansion of agricultural and urban land use on subaerial deltas and landfilling of subaqueous deltas have large impacts on holocene deltas here we quantified the volume of the holocene deltaic deposits in the tama river lowland located in the tokyo metropolitan area by analyzing 3872 existing borehole sections using gis and evaluated artificial land transformation the total volume of deltaic deposits accumulated during the past 9000 years was estimated to be 3925 106 m3 of which artificially deformed near surface material ad 676 106 m3 occupies approximately 17 this ratio is much larger than that in the nobi plain 4 6 in the nagoya metropolitan area suggesting that the impact of anthropogenic disturbance on the delta has been greater in tokyo than in the nagoya metropolitan area approximately 71 of ad is distributed in the seaward area where landfills were created mainly after the taisho period 1912 1926 the source of the ad is considered to be dredged soil construction waste soil and mountain sand the remaining 29 of ad occurred in the landward area floodplain and delta plain and likely originates from the in situ disturbed sediments of the delta plain and floodplain in addition to earth fill the seaward ad deposits including redeposition by dredging within the delta accumulated at a rate of 4 79 106 m3 year which is much higher than that of the accumulation of natural deltaic deposits during the holocene 0 36 106 m3 year this clearly shows that anthropogenic forcing has become a strong influence on geomorphological and sedimentological processes within the delta

palaeoenvironments and palaeotopography of a multilayered city during the etruscan and roman periods early interaction of fluvial processes and urban growth at pisa tuscany italy a critical geoarchaeological approach based on fully integrated archaeological geomorphological and stratigraphic data allowed for the identification of the palaeoenvironments palaeotopography and urban growth patterns of pisa nw italy during the etruscan first half of the 5th century bc first half of the 1st century bc and roman second half of the 1st century bc 2nd century ad periods this powerful methodology based on aerial and satellite images electrical resistivity tomography lidar and core analysis led to the reconstruction of landscape evolution highlighting human environment interactions during the etruscan and roman periods pisa saw a fast urban expansion in a dense and unstable fluvial network wide portions of the city were characterised by poorly drained conditions until the 1st century ad when the alluvial plain became well drained under increasing anthropogenic pressure roman centuriatio poorly drained floodplains and channel related backswamps represent the topographically lowest zones of the ancient pisa this city developed within an intricate pattern of palaeochannels related to two main rivers the palaeoarno which flowed in proximity of its present position and the former palaeoserchio river known as auser flowing in the northern part of the city since etruscan times a mounded relief was formed in the historical city centre of pisa becoming wider and more prominent up to ca 2 m a s l during the roman period concomitant with a southward rapid expansion of the urban tissue nevertheless the urban growth patterns substantially followed the etruscan city s fabric with marked concentration of the urban structures public and private buildings and manufacturing sites on the northern relief close to the auser the auser river thus played a crucial role in the environmental and topographic evolution of the city area

attenuation of millennial scale events by bioturbation in marine sediments the discovery of large millennial scale oscillations 1 10 kyr period in climate records from ice cores and marine sediments in the north atlantic has motivated the search to understand their cause and evaluate the geographic extent of this variability one uncertainty in comparing marine geologic records of millennial scale variability is the extent to which mixing of sediment by organisms at the seafloor bioturbation may attenuate millennial scale events in the stratigraphic record evidence of attenuation of millennial variability can be found in cores with sedimentation rates in the range of 5 15 cm kyr modeling the attenuation of a hypothetical input time series similar to gisp2 using a moderate level of mixing provides estimates of attenuation as a function of sedimentation rate the amplitude of a 4 kyr duration event is reduced by 50 for sedimentation rates10 cm kyr and reduced by 20 for sedimentation rates of 20 cm kyr minimal attenuation 5 is achieved only when the sedimentation rate exceeds 50 cm kyr for a 4 kyr duration event and 70 cm kyr for a 2 kyr duration event the intensity of mixing plays a role in determining how much attenuation occurs the amplitude of a 4 kyr duration event in a 10 cm kyr core is reduced by 75 under strong mixing or reduced by 25 under weak mixing this study indicates that the original amplitude of dansgaard oeschger do millennial scale events observed during the last glacial may be twice the observed amplitude for cores with sedimentation rates 10 20 cm kyr that have experienced moderate bioturbation regional comparisons of the amplitude of millennial scale variability will require cores with weak mixing or sedimentation rates exceeding 50 cm kyr in order to avoid biased estimates of the amplitude of millennial scale 4 kyr duration variability

middle to late holocene environmental evolution of the pisa coastal plain tuscany italy and early human settlements a cross disciplinary sedimentological geochemical micropalaeontological and archaeological examination of 12 continuous cores up to 20 m long integrated with stratigraphical geomorphological and historical investigations allows for reliable delineation of the middle late holocene environmental evolution in the pisa old town area with special emphasis on the etruscan age transition depositional facies were identified through integration of sedimentological and micropalaeontological benthic foraminifers ostracods phytoclasts and palynomorphs data while sediment dispersal patterns were reconstructed on the basis of geochemical analyses facies architecture was chronologically constrained by combined archaeological and radiocarbon dating the turnaround from early holocene transgressive conditions to the ensuing middle late holocene phase of sea level highstand is witnessed by a prominent shallowing upward succession of lagoonal paludal and then poorly drained floodplain deposits supplied by two river systems arno and serchio this regressive trend reflecting coastal progradation under nearly stable sea level conditions was interrupted by widespread swamp development close to the iron etruscan age transition the expansion of vast low lying paludal areas across the alluvial plain was mostly induced by the intricate short term evolution of the meandering arno and serchio river systems these changes in the fluvial network which occurred during a period of variable climate conditions strongly influenced the early etruscan culture 7th 5th century bc in terms of human settlement and society behaviour conversely a strong impact of human frequentation on depositional environments is observed at the transition to the roman age from the 1st century bc onwards when the wetlands were drained and the modern alluvial plain started to form the palaeoenvironmental reconstruction fits in with the original geographical descriptions mentioned in strabo s chronicles and provides chronologically constrained data of fluvial evolution from the pisa old town area

links between climate and sea levels for the past three million years the oscillations between glacial and interglacial climate conditions over the past three million years have been characterized by a transfer of immense amounts of water between two of its largest reservoirs on earth the ice sheets and the oceans since the latest of these oscillations the last glacial maximum between about 30 000 and 19 000 years ago approximately 50 million cubic kilometres of ice has melted from the land based ice sheets raising global sea level by approximately 130 metres such rapid changes in sea level are part of a complex pattern of interactions between the atmosphere oceans ice sheets and solid earth all of which have different response timescales the trigger for the sea level fluctuations most probably lies with changes in insolation caused by astronomical forcing but internal feedback cycles complicate the simple model of causes and effects

the anthropic landscape imprint around one of the largest roman hydraulic gold mines in europe sierra del teleno nw spain abstract this study explores the information gathered from the landscape transformation that occurred during the intense period of roman hydraulic gold mining activity in northwest spain the sierra del teleno and its surroundings are characterised by the presence of quaternary glacial and periglacial deposits and locally neogene alluvial sediments which were intensely mined by the romans however the mining debris often obscures natural deposits making their identification and description a challenging task the aim of this study is to determine the existence of specific geomorphological features that can improve the identification of anthropic elements related to mining activity river captures and widened drainage systems are among the most outstanding structures remaining due to the extent and complexity of the work involved however other mining elements such as anthropic modification of alluvial fans moraine deposits and rock ridges are also evident in the landscape in many cases these remains are linked to the hydrologic infrastructure found in the area which mainly comprises an extensive system of natural and man made channels and distribution water tanks difficulties arise in areas where no such structures are found thus the use of geomorphic elements and patterns can help to distinguish natural and anthropic landforms using this approach therefore we have performed the first systematic and detailed analysis of the morphological imprint of roman hydraulic gold mining activity on the landscape these data will help piece together the puzzle of how the landscape was transformed by roman mining activity and can contribute to discussions surrounding the new epoch the anthropocene