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

paleocene sea level and productivity changes at the southern tethyan margin el kef tunisia integrated analysis of quantitative distribution patterns of organic walled dinoflagellate cysts dinocysts and benthic foraminifera from the paleocene el kef section nw tunisia allows the reconstruction of sea level and productivity fluctuations our records indicate that the environment evolved from an initially oligotrophic open marine outer neritic to upper bathyal setting towards a more eutrophic inner neritic setting influenced by coastal upwelling by the end of the paleocene an overall second order change in paleodepth is reflected by both microfossil groups from the base of planktic foraminifera zone p4 onwards the main phase of shallowing is evidenced by an increase of inner neritic dinocysts of the areoligera group disappearance of deeper water benthic foraminifera and increasing dominance of shallow marine taxa several buliminids haplophragmoides spp trochammina spp the total magnitude of this shallowing is obscured by interaction with a signal of eutrophication but estimated to be around 150 m from 200 to 50 m superimposed on the overall trend third order sea level fluctuations have been identified and correlated to sequences in other regions paleoproductivity indicators notably protoperidinioid dinocysts and buliminids show a trend from an oligotrophic to a eutrophic setting d 2005 elsevier b v all rights reserved

warm and wet conditions in the arctic region during eocene thermal maximum 2 several episodes of abrupt and transient warming each lasting between 50 000 and 200 000 years punctuated the long term warming during the late palaeocene and early eocene 58 to 51 myr ago epochs1 2 these hyperthermal events such as the eocene thermal maximum 2 emt2 that took place about 53 5 myr ago2 are associated with rapid increases in atmospheric co2 content however the impacts of most events are documented only locally86 here we show on the basis of estimates from the tex 86 proxy that sea surface temperatures rose by 3 5 c in the arctic ocean during the emt2 dinoflagellate fossils demonstrate a concomitant freshening and eutrophication of surface waters which resulted in euxinia in the photic zone the presence of palm pollen implies5 that coldest month mean temperatures over the arctic land masses were no less than 8 c in contradiction of model simulations that suggest hyperthermal winter temperatures were below freezing6 in light of our reconstructed temperature and hydrologic trends we conclude that the temperature and hydrographic responses to abruptly increased atmospheric co2 concentrations were similar for the etm2 and the better described palaeocene eocene thermal maximum7 8 55 5 myr ago 2009 macmillan publishers limited all rights reserved

dissociation of oceanic methane hydrate as a cause of the carbon isotope excursion at the end of the paleocene isotopic records across the latest paleocene thermal maximum lptm indicate that bottom water temperature increased by more than 4 c during a brief time interval 104 years of the latest paleocene 55 6 ma there also was a coeval 2 to 3 excursion in the 13c of the ocean atmosphere inorganic carbon reservoir given the large mass of this reservoir a rapid 13c shift of this magnitude is difficult to explain within the context of conventional hypotheses for changing the mean carbon isotope composition of the ocean and atmosphere however a direct consequence of warming bottom water temperature from 11 to 15 c over 104 years would be a significant change in sediment thermal gradients and dissociation of oceanic ch4 hydrate at locations with intermediate water depths in terms of the present day oceanic ch4 hydrate reservoir thermal dissociation of oceanic ch4 hydrate during the lptm could have released greater than 1 1 to 2 1 1018 g of carbon with a 13c of approximately 60 the release and subsequent oxidation of this amount of carbon is sufficient to explain a 2 to 3 excursion in 13c across the lptm fate of ch4 in oceanic hydrates must be considered in developing models of the climatic and paleoceanographic regimes that operated during the lptm

ferrimagnetic iron sulfide formation and methane venting across the paleocene eocene thermal maximum in shallow marine sediments ancient west siberian sea

climatic and environmental changes across the early eocene climatic optimum at mid waipara river canterbury basin new zealand abstract the cretaceous paleogene marine sedimentary succession exposed in the banks of the middle reaches of the waipara river referred to as mid waipara north canterbury new zealand has been the subject of several high profile studies of paleogene paleoclimate over the past decade it is one of relatively few sections globally where a multi proxy approach is possible due to the good preservation of microfossils and organic biomarkers the eocene section is also well dated by magnetostratigraphy and biostratigraphy based on planktic foraminifera calcareous nannofossils and dinoflagellate cysts dinocysts here we build on this previous work and undertake a comprehensive analysis of paleontological and geochemical indicators of climatic and environmental changes through the early middle eocene part of the section with particular focus on the early eocene climatic optimum eeco 53 26 49 14 ma we correlate a 33 5 m thick interval with the eeco based on biostratigraphy magnetostratigraphy tex86 paleothermometry and bulk carbonate 13c our new sea surface temperature sst record based on tex86 agrees with a previous lower resolution record based on tex86 and planktic foraminiferal 18o and mg ca ratios the eeco interval in this section extends from the upper part of the new zealand waipawan stage to the mangaorapan heretaungan stage boundary at 49 27 ma the eeco onset is not exposed but the termination is well constrained by a fall in sst and shift to more positive 13c values six negative carbon isotope excursions cies are recognised within the eeco and are tentatively correlated with cies j k m o q t and c22nh4 in the global 13c compilation the cies are associated with warmer ssts indicating that they represent hyperthermals the bayspar tex86 calibration indicates sst increased by as much as 12 c from the early eocene 55 ma to the eeco where sst peaked at 35 c sst gradually declined from mid eeco 51 ma into the middle eocene the marked warming in the early eeco is associated with the highest abundance of warm water taxa in calcareous nannofossil and dinocyst assemblages the highest proportion of planktic foraminifera and a coeval long term shift to abundant angiosperm vegetation primarily driven by a rise in casuarinaceae there is good agreement between tex86 and marine microfossil based proxies for temperature providing confidence that both approaches are useful guides to past water temperature warm water marine taxa are most abundant in the eeco but are not dominant comparison of the abundance of nannofossil warm water taxa between mid waipara and a low latitude site on shatsky rise suggests the latitudinal temperature gradient between mid and low latitudes in the eeco was greater than the tex86 proxy implies there is no clear evidence for enhanced sedimentation rates associated with the eeco in contrast to evidence from the nearby mead stream section superabundant homotryblium a euryhaline dinocyst in the early and middle eeco suggests elevated salinity and or stratified surface waters and there is no clear evidence of increased surface productivity associated with the eeco declining sst in the late eeco 50 ma corresponds with an increase in cool water taxa and terrigenous material this article highlights the importance of combining well calibrated paleontological and geochemical records to better constrain and understand past warm climate states

subtropical climate conditions and mangrove growth in arctic siberia during the early eocene the early eocene ca 56 47 8 ma was an interval of exceptional warmth with reduced pole to equator temperature gradients climate proxies indicate mean annual air temperatures mats and sea surface temperatures ssts exceeding 8 18 c and frost free mild winters in polar areas features that have proven difficult to reproduce with the most elaborate climate models a full appraisal of the early eocene polar climate has been however limited by possible seasonal biases associated with geochemical proxies and the lack of data from the vast eurasian arctic here we present multiproxy data from lower middle eocene coastal plain sediments of the new siberian islands russia showing that taxodioid cupressaceae palms and the mangrove avicennia grew in arctic siberia above 72 n under air temperatures averaging 16 21 c annually and 5 5 14 c in winter kaolinite contents are exceptionally high up to 60 of clay assemblages and comparable to those found in present day subtropical soils formed under high mean annual precipitation map 1000 mm and warm mat 15 c conditions the avicennia pollen records the northernmost mangrove growth ever documented and indicates early eocene ssts exceeding 13 c in winter and 18 c in summer considering the high map estimated for arctic siberia and other pan arctic landmasses we propose that the heat from warm river waters draining into the arctic might have amplified early eocene polar warmth our results provide the first climate constraints for the early eocene of arctic siberia and support the view that most climate models underestimate polar warming in greenhouse conditions

thermogenic methane release as a cause for the long duration of the petm the paleocene eocene thermal maximum petm 56 ma was a 170 000 y 170 kyr period of global warming associated with rapid and massive injections of 13c depleted carbon into the ocean atmosphere system reflected in sedimentary components as a negative carbon isotope excursion cie carbon cycle modeling has indicated that the shape and magnitude of this cie are generally explained by a large and rapid initial pulse followed by 50 kyr of 13c depleted carbon injection suggested sources include submarine methane hydrates terrigenous organic matter and thermogenic methane and co2 from hydrothermal vent complexes here we test for the contribution of carbon release associated with volcanic intrusions in the north atlantic igneous province we use dinoflagellate cyst and stable carbon isotope stratigraphy to date the active phase of a hydrothermal vent system and find it to postdate massive carbon release at the onset of the petm crucially however it correlates to the period within the petm of longer term 13c depleted carbon release this finding represents actual proof of petm carbon release from a particular reservoir based on carbon cycle box model i e long term ocean atmosphere sediment carbon cycle reservoir loscar model experiments we show that 4 12 pulses of carbon input from vent systems over 60 kyr with a total mass of 1 500 pg of c consistent with the vent literature match the shape of the cie and pattern of deep ocean carbonate dissolution as recorded in sediment records we therefore conclude that ch4 from the norwegian sea vent complexes was likely the main source of carbon during the petm following its dramatic onset

towards quantitative environmental reconstructions from ancient non analogue microfossil assemblages ecological preferences of paleocene eocene dinoflagellates abstract we explore a novel approach towards quantification of paleo ecological signals from non analogue microfossil assemblages by quantifying relations between assemblages and high quality geochemical and sedimentological data from sedimentary archives we test this approach using one group of microfossils the organic cysts of dinoflagellates dinocysts which are widely used in shelf and open marine settings for biostratigraphy and reconstructions of past environments and environmental change similar to other microfossil groups dinocysts can be used to reconstruct environments with relatively high confidence for recent time periods as species affinities can be derived from observational and instrumental data in the absence of such data the ecology of extinct species is much less certain and as a result reconstructions in deep time are often limited to qualitative interpretations to explore if quantitative empirical relations between extinct dinocysts and high quality geochemical data can be established we study a major event of climate change the paleocene eocene thermal maximum petm 56 ma ago the petm is a particularly suitable period for this exercise as there is a multitude of large environmental perturbations associated with the transient global warming such as deoxygenation sea level rise and an accelerated hydrological cycle the synthesized published dataset exhibits better spatial and temporal coverage compared to any other period in deep time we extract empirical relations for the abundance of previously proposed paleoecological groups as a function of independent environmental proxies for example sea surface temperature and terrestrial organic matter input the results unequivocally illustrate that many dinocysts show relations to several of the reconstructed environmental variables notably we show that one genus apectodinium and an ecogroup epicystal goniodomidae required sea surface temperatures in excess of 20 c and 25 c respectively while one species florentinia reichartii was only abundant between 30 and 35 c other groups apparently favored either a limited spiniferites or high senegalinium terrestrial input to the study site relating to salinity nutrient levels or suspended sediment load i e murkiness crucially our work shows that the validation and quantification of ecological signals by independent environmental proxy data provides the opportunity to extract more quantitative information from a wide range of non analogue microfossil assemblages while this approach is not limited to any specific group of microfossils or macrofossils we stress that proper calibration datasets high quality sedimentological and geochemical proxy records are needed and should ideally have decent geographical coverage and include one or more environmental perturbations using this approach such empirical relations can be established for a wide range of microfossil groups that have highly complementary geological records which increases the value of existing data and ensures future application of microfossil based paleoecology

alluvial architecture of the holocene lower mississippi valley u s a and a comparison with the rhine meuse delta the netherlands abstract the proportion and arrangement of channel belt deposits in alluvial successions alluvial architecture is not known in detail for most modern settings therefore the alluvial architecture of the holocene lower mississippi valley lmv between greenville mississippi and baton rouge louisiana was studied to improve estimation of parameters relevant to alluvial architecture modeling alluvial architecture parameters sand body width thickness ratio sbw sbt channel belt deposit proportion cdp overbank deposit proportion odp and connectedness ratio cr are estimated from three cross valley sections based on lithologic borings sbw sbt and cdp decrease in a downstream direction for example cdp is 0 6 upstream and 0 3 downstream odp shows an opposite trend and is at a maximum 0 7 in the downstream part of the study area cr is low throughout the study area because most channel belts in our cross sections are unconnected the alluvial architecture in the lmv also seems to change over time because late holocene channel belts tend to be wider than the early holocene channel belts the observed trends in the alluvial architecture parameters are related to the ratio between channel belt width and floodplain width variations in aggradation rate location of the cross sections relative to avulsion sites and differential subsidence the alluvial architecture of the lmv is compared to that of the holocene rhine meuse delta to identify common controls on alluvial architecture despite differences in geographic setting the alluvial architecture of the lmv is similar to that of the rhine meuse delta we conclude that alluvial architecture of both fluvial systems is strongly controlled by channel belt geometry floodplain geometry and aggradation rate these in turn are influenced by extrinsic factors i e base level discharge sediment supply tectonics and pre existing topography as well as intrinsic factors i e lateral channel migration rate subsoil erodibility differential floodplain aggradation and avulsion mechanisms therefore the interaction between extrinsic and intrinsic factors should be considered in all alluvial architecture studies

derivation of mesozoic adakitic magmas from ancient lower crust in the north china craton three mesozoic plutons were intruded into the archean granulite terrains in northern margin of the north china craton adjacent to the granulite xenolith bearing tertiary hannuoba basalts they are triassic guzuizi and honghualiang granites and early cretaceous zhuanzhilian diorite rocks of the three intrusions are characterized by high sr 576 1216 ppm and na2o 4 0 low y 18 ppm and heavy rare earth elements yb 1 8 ppm these features are similar to modern adakites siliceous rocks with high sodium aluminum and strontium and low heavy rare earth element and yttrium contents from island arcs and archean high al tonalite trondhjemite granodiorite ttg however they are distinctly potassium rich and their evolved strontium neodymium and hafnium isotopic compositions and inherited zircon ages coincide with those of the archean granulites and the hannuoba granulite xenoliths such features cannot readily be explained with previous models of the origin of adakites and ttgs we propose that these adakitic rocks are formed by partial melting of ancient lower crust and that the restites are represented by some of the hannuoba granulite xenoliths we further argue that this could be one major mechanism to generate voluminous mesozoic adakitic magmas in the eastern north china craton our hypothesis can also explain the discrepancies in ages and compositions between the granulite terrains and xenoliths and implies that crustal anatexis may be one of the major processes controlling the chemical differentiation of the continental crust

a novel proxy for terrestrial organic matter in sediments based on branched and isoprenoid tetraether lipids we propose a novel tracer for terrestrial organic carbon in sediments based on the analysis of tetraether lipids using high performance liquid chromatography mass spectrometry hplc ms analysis of terrestrial soil and peats shows that branched tetraether lipids are predominant in terrestrial environments in contrast to crenarchaeol the characteristic membrane lipid of non thermophilic crenarchaeota which is especially abundant in the marine and lacustrine environment based on these findings an index was developed the so called branched and isoprenoid tetraether bit index based on the relative abundance of terrestrially derived tetraether lipids versus crenarchaeol this bit index was applied to surface sediments from the angola basin where it was shown to trace the outflow of the congo river furthermore analyses of particulate organic matter from the north sea showed relatively higher bit indices in water column particulate organic matter near large river inputs a survey of globally distributed marine and lacustrine surface sediments shows that the bit index in these environments correlates with the relative fluvial input of terrestrial organic material making this index generally applicable the new proxy allows the rapid assessment of the fluvial input of terrestrial organic material in immature sediments up to 100 ma old

basaltic explosive volcanism but no comet impact at the paleocene eocene boundary high resolution chemical and isotopic records from egypt spain and denmark in the search for a triggering mechanism for the paleocene eocene p e boundary event 55 ma centimeter resolution chemical e g ir os pt and isotope e g os o 187 os 188 he 3 he 4 sr 87 sr 86 records across this boundary have been established for six uplifted marine sections in egypt spain and denmark the sections studied represent some of the stratigraphically most complete records across the onset of the carbon isotopic excursion cie and associated benthic foraminifera extinctions that mark the paleocene eocene boundary high sensitivity analyses failed to uncover evidence of extraterrestrial element or isotope enrichments in the six sections refuting the hypothesis of a major comet impact at the boundary preliminary searches for other impact indicative features such as spherules or shocked quartz also gave negative results in the danish section studied three basaltic ir rich ash layers occur at the paleocene eocene boundary but no similar ashes were found in egypt or spain the three ashes represent the earliest known manifestation of an unusual i to 2 million year long phase of explosive basaltic volcanism in the faero greenland region this volcanism is synchronous with major flood basalt effusions in east greenland and is associated with prominent paleogeographic changes in the high latitude north atlantic region discharge of mantle derived os to seawater during this volcanism may explain a small decrease in os o 187 os o 188 ratio at the paleocene eocene boundary in the zumaya section in spain the environmental perturbations at the paleocene eocene boundary appear to have been triggered by basaltic volcanism but any model for the detailed causal relation remains speculative c 2004 elsevier b v all rights reserved less

stable warm tropical climate through the eocene epoch earth s climate cooled from a period of extreme warmth in the early eocene epoch ca 50 ma to the early oligocene ca 33 ma when a large ice cap first appeared on antarctica evidence from the planktonic foraminifer oxygen isotope record in deep sea cores has suggested that tropical sea surface temperatures declined by 5 10 degrees over this interval eventually becoming much cooler than modern temperatures here we present paleotemperature estimates from foraminifer isotopes and the membrane lipids of marine crenarcheota from new drill cores in tanzania that indicate a warm and generally stable tropical climate over this period we reinterpret the previously published isotope records in the light of comparative textural analysis of the deep sea foraminifer shells which shows that in contrast to the tanzanian material they have been diagenetically recrystallized we suggest that increasingly severe alteration of the deep sea plankton shells through the eocene produced a diagenetic overprint on their oxygen isotope ratios that imparts the false appearance of a tropical sea surface cooling trend this implies that the long term eocene climatic cooling trend occurred mainly at the poles and had little effect at lower latitudes

dinoflagellate cyst assemblages biostratigraphy and paleoenvironment of a paleocene early eocene sedimentary succession in the northern niger delta basin comparison with low mid and high latitude regions abstract this study represents a contribution to the late paleocene early eocene biostratigraphy in a low latitude stratigraphic setting where published studies are few in comparison with mid and high latitude regions we generated data for 62 dinoflagellate cysts from a comprehensive analysis of 33 samples covering a 713 m interval in the alo 1 well in the northern niger delta anambra basin nigeria dinoflagellate cyst recovery in the samples varies from very good to poor and the specimens are commonly well preserved we calibrate the dinoflagellate cyst data with recent biozonation schemes for odp hole 959d cote d ivoire ghana transform margin in the eastern equatorial atlantic which allowed for a valid comparison with published studies in well dated rock sections in northwestern europe the mediterranean region new zealand and tasmania our observations show that there is better correlation between tropical and mid latitude dinoflagellate cyst assemblages compared to those in high latitude regions we use the last occurrence and or last abundance events of dinoflagellate cysts to identify four biostratigraphic zones zone e to zone h in the alo 1 well lithostratigraphic and biostratigraphic analyses suggest a late selandian age for the contact between the imo and nsukka formations abundant thermophilic taxa that include the cordosphaeridium group and apectodinuim dominate the assemblage recovered in the depositional succession the late selandian to early thanetian sediments are dominated by the cordosphaeridium group and are succeeded by abundant to superabundant marker species of apectodinium in the late thanetian to ypresian the superabundance of apectodinium is significant because it is indicative of the global intense climatic warming that characterized the late thanetian to early ypresian the alo 1 well dinoflagellate cyst data also suggest deposition under proximal inner neritic conditions that preserved an assemblage dominated by species of cordosphaeridium damassadinium ifecysta and polysphaeridium

a magneto and chemostratigraphically calibrated dinoflagellate cyst zonation of the early palaeogene south pacific ocean abstract investigation of the early palaeogene palaeoecological and palaeoclimatological evolution of the polar regions is hindered by the absence of calcite microfossils in sedimentary archives which are conventionally the main dating tool to overcome this problem we have generated large datasets of organic dinoflagellate cyst dinocyst assemblages from southern ocean shelf sediments over the past decade and we here calibrate these to the geomagnetic polarity time scale gpts using magnetostratigraphy and stable isotope stratigraphy this now for the first time allows a high resolution southern pacific ocean dinocyst zonation for the late palaeocene to late eocene 58 36 million years ago ma we compile published dinocyst chronologies from ocean drilling program odp hole 1171d on the south tasman rise hole 1172a d on the east tasman plateau and integrated ocean drilling program iodp hole u1356a on the wilkes land margin correlation to dinocyst zonations from new zealand lead to revisions of the magnetostratigraphic age model at holes 1171d and 1172a d stable carbon and oxygen isotope records reveal the stratigraphic location of the palaeocene eocene thermal maximum 56 ma and the middle eocene climatic optimum 40 ma respectively the resulting zonation consists of thirteen dinocyst zones calibrated to the geomagnetic polarity time scale gpts of vandenberghe et al 2012 which can likely be applied to the entire southern ocean finally we apply the revised stratigraphy to all published tex86 data a biomarker based proxy for sea surface temperature sst from odp site 1172 to assess long term climate evolution this shows that southwest pacific sst trends mimic the global compilation of benthic foraminiferal oxygen isotopes even better than previously appreciated

exhuming the top end of north america episodic evolution of the eurekan belt and its potential relationships to north atlantic plate tectonics and arctic climate change

arctic late paleocene early eocene paleoenvironments with special emphasis on the paleocene eocene thermal maximum lomonosov ridge integrated ocean drilling program expedition 302 we reconstruct the latest paleocene and early eocene 57 50 ma environmental trends in the arctic ocean and focus on the paleocene eocene thermal maximum petm 55 ma using strata recovered from the lomonosov ridge by the integrated ocean drilling program expedition 302 the lomonosov ridge was still partially subaerial during the latest paleocene and earliest eocene and gradually subsided during the early eocene organic dinoflagellate cyst dinocyst assemblages point to brackish and productive surface waters throughout the latest paleocene and early eocene dinocyst assemblages are cosmopolitan during this time interval suggesting warm conditions which is corroborated by tex86 reconstructed temperatures of 15 18 c inorganic geochemistry generally reflects reducing conditions within the sediment and euxinic conditions during the upper lower eocene spectral analysis reveals that the cyclicity recorded in x ray fluorescence scanning fe data from close to eocene thermal maximum 2 53 ma presence confirmed by dinocyst stratigraphy is related to precession within the lower part of the petm proxy records indicate enhanced weathering runoff anoxia and productivity along with sea level rise on the basis of total organic carbon content and variations in sediment accumulation rates excess organic carbon burial in the arctic ocean appears to have contributed significantly to the sequestration of injected carbon during the petm

climate model and proxy data constraints on ocean warming across the paleocene eocene thermal maximum article constraining the greenhouse gas forcing climatic warming and estimates of climate sensitivity across ancient large transient warming events is a major challenge to the palaeoclimate research community here we provide a new compilation and synthesis of the available marine proxy temperature data across the largest of these hyperthermals the paleocene eocene thermal maximum petm this includes the application of consistent temperature calibrations to all data including the most recent set of calibrations for archaeal lipid derived palaeothermometry this compilation provides the basis for an informed discussion of the likely range of petm warming the biases present in the existing record and an initial assessment of the geographical pattern of petm ocean warming to aid interpretation of the geographic variability of the proxy derived estimates of petm warming we present a comparison of this data with the patterns of warming produced by high pco2 sim ulations of eocene climates using the hadley centre atmosphere ocean general circulation model aogcm hadcm3l on the basis of this comparison and taking into account the patterns of intermediate water warming we estimate that the global mean surface temperature anomaly for the petm is within the range of 4 to 5 c

early paleogene temperature history of the southwest pacific ocean reconciling proxies and models we present a new multiproxy tex86 18o and mg ca marine temperature history for canterbury basin eastern new zealand that extends from middle paleocene to middle eocene including the paleocene eocene thermal maximum petm and early eocene climatic optimum eeco in light of concerns that proxy based sea surface temperature sst estimates are untenably warm for the southwest pacific during the eocene we review the assumptions that underlie the proxies and develop a preliminary paleo calibration for tex86 that is based on four multiproxy eocene records that represent an sst range of 15 34 c for the southwest pacific paleogene we show that tex86l exhibits the best fit with the eocene paleo calibration ssts derived from related proxies tex86h 1 tex86 exhibit a systematic warm bias that increases as tex86 values decrease a warm bias of 4 7 c where tex86 0 7 the tex86l proxy indicates that southwest pacific sst increased by 10 c from middle paleocene to early eocene with sst maxima of 26 28 c tropical during the petm and eeco and an sst minimum of 13 16 c cool warm temperate at the middle late paleocene transition 58 7 ma the base of the eeco is poorly defined in these records but the top is well defined in canterbury basin by a 2 5 c decrease in sst and bottom water temperature bwt in the latest early eocene 49 3 ma bwt falls from a maximum of 18 20 c in the eeco to 12 14 c in the middle eocene overall cooler temperatures are recorded in the mid waipara section which may reflect a deeper 500 m water depth and less neritic depositional setting compared with hampden and odp 1172 200 m water depth the high ssts and bwts inferred for the petm and eeco can be reconciled with eocene coupled climate model results if the proxies are biased towards seasonal maxima and the likely effect of a proto east australian current is taken into account

mid latitude continental temperatures through the early eocene in western europe branched glycerol dialkyl glycerol tetraethers brgdgts are increasingly used to reconstruct mean annual air temperature maat during the early paleogene however the application of this proxy in coal deposits is limited and brgdgts have only been detected in immature coals i e lignites using samples recovered from schoningen germany 48 n palaeolatitude we provide the first detailed study into the occurrence and distribution of brgdgts through a sequence of early eocene lignites and associated interbeds brgdgts are abundant and present in every sample in comparison to modern studies changes in vegetation type do not appear to significantly impact brgdgt distributions however there are subtle differences between lignites representing peat forming environments and siliciclastic nearshore marine interbed depositional environments using the most recent brgdgt temperature calibration matmr developed for soils we generate the first continental temperature record from central western continental europe through the early eocene lignite derived maat estimates range from 23 to 26 c while those derived from the nearshore marine interbeds exceed 20 c these estimates are consistent with other mid latitude environments and model simulations indicating enhanced mid latitude early eocene warmth in the basal part of the section studied warming is recorded in both the lignites 2 c and nearshore marine interbeds 2 3 c this culminates in a long term temperature maximum likely including the early eocene climatic optimum eeco although this long term warming trend is relatively well established in the marine realm it has rarely been shown in terrestrial settings using a suite of model simulations we show that the magnitude of warming at schoningen is broadly consistent with a doubling of co2 in agreement with late paleocene and early eocene pco2 estimates

paleocene eocene warming and biotic response in the epicontinental west siberian sea we present a paleocene eocene ca 60 52 ma sea surface temperature record from sediments deposited in the epicontinental west siberian sea tex86 paleothermometry indicates long term late paleocene 17 c ca 59 ma to early eocene 26 c at 52 ma sea surface warming consistent with trends previously observed for the southern ocean and deep oceans photic zone and seafloor anoxia developed as temperatures rose by 7 c to 27 c during the paleocene eocene thermal maximum petm based on paired palynological and tex86 data we suggest that the minimum temperature for the proliferation of paleocene and early eocene members of the dinoflagellate family wetzelielloideae which includes the petm marker taxon apectodinium was 20 c

the planktonic foraminiferal response to the paleocene eocene thermal maximum on the atlantic coastal plain abstract planktonic foraminiferal assemblages in two cores from maryland and new jersey show evidence for significant changes in surface ocean habitats on the continental shelf during the paleocene eocene thermal maximum petm at both sites significant assemblage shifts occur immediately before the onset of the event these changes include the appearance of abundant triserial biserial species as well as rare excursion taxa which are limited to the interval of the carbon isotope excursion at deep sea sites the assemblage shifts signal the development of new habitats immediately prior to the onset of the petm likely involving warming surface ocean acidification increased stratification and oligotrophy a sharp increase in diversity at the onset of the event is interpreted as a further increase in stratification and warming as well as increased water depth and more eutrophic conditions finally we observe variant morphologies of several planktonic foraminifera which may also signal the response of the assemblage to environmental perturbation

eocene to oligocene dinoflagellate cysts from the tattofte section western external rif northwestern morocco biostratigraphy paleoenvironments and paleoclimate abstract the palynological analysis of the eocene oligocene succession from the tattofte section in the western external rif northwestern morocco reveals the presence of well preserved and diverse assemblage rich in dinoflagellate cysts dinocysts qualitative analyses especially of the dinocysts differentiate the individual stages of the deposits while quantitative analyses permit paleoenvironmental and paleoclimatic interpretations we assign the lower part of the tattofte section to the middle eocene lutetian and bartonian and its upper part to the upper oligocene chattian and define a hiatus spanning the late eocene priabonian and early oligocene rupelian the dinocyst marker events used for the biostratigraphic interpretations include the first and last occurrences of marker species such as batiacasphaera compta castellodinium compactum cerebrocysta bartonensis distatodinium biffii distatodinium paradoxum distatodinium ellipticum enneadocysta arcuata homotryblium floripes hystrichokolpoma bullatum impagidinium velorum lentinia serrata pentadinium imaginatum rhombodinium spinula saturnodinium perforatum and ynezidinium brevisulcatum as well as the chiropteridium spp acmes and we equate the chattian with the dinocyst distatodinium biffii zone of brinkhuis et al 1992 changes in the relative abundances of selected dinocyst groups spores and pollen lead to the distinction from oldest to youngest of four marine environments 1 marginal marine to coastal inner neritic under relatively warm water during the middle eocene 2 outer neritic to oceanic during a transgressive regime in the early chattian 3 fluctuating restricted to open marine in the middle chattian and 4 shallow coastal to open marine due to sea level fall at the top of the section in the latest chattian suggested by the chiropteridium spp acmes the acmes of selected thermophilic dinocyst taxa such as polysphaeridium spp and homotryblium spp suggest warm water marine conditions which may be related to the middle eocene climatic optimum meco and late oligocene warming

mid cenozoic tectonic and paleoenvironmental setting of the central arctic ocean drilling results from the integrated ocean drilling program s arctic coring expedition acex to the lomonosov ridge lr document a 26 million year hiatus that separates freshwater influenced biosilica rich deposits of the middle eocene from fossil poor glaciomarine silty clays of the early miocene detailed micropaleontological and sedimentological data from sediments surrounding this mid cenozoic hiatus describe a shallow water setting for the lr a finding that conflicts with predrilling seismic predictions and an initial postcruise assessment of its subsidence history that assumed smooth thermally controlled subsidence following rifting a review of cenozoic tectonic processes affecting the geodynamic evolution of the central arctic ocean highlights a prolonged phase of basin wide compression that ended in the early miocene the coincidence in timing between the end of compression and the start of rapid early miocene subsidence provides a compelling link between these observations and similarly accounts for the shallow water setting that persisted more than 30 million years after rifting ended however for much of the late paleogene and early neogene tectonic reconstructions of the arctic ocean describe a landlocked basin adding additional uncertainty to reconstructions of paleodepth estimates as the magnitude of regional sea level variations remains unknown

temperature changes across the paleocene eocene thermal maximum a new high resolution tex86 temperature record from the eastern north sea basin abstract the paleocene eocene thermal maximum petm 55 9 ma was a hyperthermal event associated with large carbon cycle perturbations sustained global warming and marine and terrestrial environmental changes one possible trigger and or source of the carbon release that initiated the petm is the emplacement of the north atlantic igneous province naip this study focuses on an expanded section of marine clays and diatomite on fur island in northern denmark where the entire petm sequence has been identified by a negative 4 5 13 ctoc excursion this remarkably well preserved section also contains 180 interbedded ash layers sourced from the naip making it an ideal site for investigating the correlations between large scale volcanism and environmental changes this study provides a new and complete high resolution tex86 derived sea surface temperature sst reconstruction over the entire petm and the post petm section up to about 54 6 ma the palaeothermometry record indicates an apparent short lived cooling episode in the late paleocene followed by a pronounced temperature response to the petm carbon cycle perturbations with a 10 c sst increase during the petm onset up to 33 c extreme ssts fall shortly after the petm onset and continue to decrease during the petm body and recovery down to anomalously cool ssts post petm 11 23 c both phases of potential cooling coincide with proxies of active naip volcanism suggesting a causal connection although several overprinting non thermal factors complicate interpretations of the tex86 values indices of effusive and explosive naip volcanism are largely absent from the danish stratigraphy during the petm body though a re emergence toward the end of the petm suggest naip volcanism might have played a role in the petm termination in the north sea this new sst record completes the previous fragmented view of climate changes at this globally important petm site and indicates large temperature variations in the north sea during the earliest eocene that are possibly linked to naip volcanism

distributional variations in marine crenarchaeotal membrane lipids a new tool for reconstructing ancient sea water temperatures it has recently been shown that membrane lipids of marine crenarchaeota a ubiquitous and abundant component of plankton occur in relatively high concentrations in recent and ancient sediments in this study we investigated the environmental controls on the relative distribution of these lipids in surface sediments we especially focussed on temperature as it is known from the thermophilic genetic relatives of marine crenarchaetoa that the composition of their membrane strongly depends on growth temperature indeed a significant linear correlation r2 0 92 is found between the number of cyclopentane rings in sedimentary membrane lipids derived from marine crenarchaeota and the annual mean sea surface temperatures this suggests that the mechanism of physical adaptation of their membrane compositions to temperature is identical to that of their thermophilic relatives in turn archaeal lipid distributions in sediments may thus allow the reconstruction of sea water temperatures of ancient marine environments

rapid emergence of subaerial landmasses and onset of a modern hydrologic cycle 2 5 billion years ago the history of the growth of continental crust is uncertain and several different models that involve a gradual decelerating or stepwise process have been proposed1 4 even more uncertain is the timing and the secular trend of the emergence of most landmasses above the sea subaerial landmasses with estimates ranging from about one billion to three billion years ago5 7 the area of emerged crust influences global climate feedbacks and the supply of nutrients to the oceans 8 and therefore connects earth s crustal evolution to surface environmental conditions9 11 here we use the triple oxygen isotope composition of shales from all continents spanning 3 7 billion years to provide constraints on the emergence of continents over time our measurements show a stepwise total decrease of 0 08 per mille in the average triple oxygen isotope value of shales across the archaean proterozoic boundary we suggest that our data are best explained by a shift in the nature of water rock interactions from near coastal in the archaean era to predominantly continental in the proterozoic accompanied by a decrease in average surface temperatures we propose that this shift may have coincided with the onset of a modern hydrological cycle owing to the rapid emergence of continental crust with near modern average elevation and aerial extent roughly 2 5 billion years ago the use of triple oxygen isotope data from continental shales spanning the past 3 7 billion years suggests that continental crust with near modern average elevation and extent emerged about 2 5 billion years ago

flat meridional temperature gradient in the early eocene in the subsurface rather than surface ocean sea surface temperature estimates from the early eocene indicate an unusually flat meridional temperature gradient a re evaluation of the proxy used to derive these temperatures argues against this interpretation