paleoclimatic significance of the stratigraphic occurrence of photosynthetic biomarker pigments in the nordic seas sedimentary chlorins and porphyrins are diagenetic products of chlorophyll molecules and are considered to be chemical fossils or biomarkers of phototrophic organisms the stratigraphic occurrence of such components was investigated in four cores from the nordic seas that span the last deglacial period the presence of chlorins in all the samples deposited during the younger dryas and at the end of the last glacial period indicated that photosynthetic activity occurred during these cold episodes and hence that ice free conditions existed at least seasonally in the nordic seas vanadyl porphyrins were found in sediments deposited during termination ia in only two of the cores close to the barents shelf we argue that they derive from erosion and advection of organic rich deposits as ice rafted debris during melting of the barents ice sheet thus we suggest that the sedimentary occurrence of vanadyl porphyrins in nordic sea cores can be used as a marker of ice rafted debris from the barents ice sheet the absence of such components during termination ib indicates that the complete destruction of the barents ice sheet took place during the first stage of the deglaciation

40ar 39ar dating and magnetostratigraphic correlation of the terrestrial cretaceous paleogene boundary and puercan mammal age hell creek tullock formations eastern montana the recovery and subsequent prolific radiation of mammals in the northern western interior of north america following the cretaceous paleogene k p boundary is well documented in rocks attributed to the puercan land mammal age the most complete puercan record is that of the tullock formation which crops out widely in garfield and mccone counties eastern montana the tullock formation overlies the dinosaur bearing hell creek formation and consists of a stratigraphic series of channel and overbank deposits from which well preserved puercan faunas have been collected these channel deposits are typically bracketed by widespread coal beds the irz and z coals mark the base of the puercan at the k p boundary as defined by the highest appearing local occurrences of in situ dinosaur fossils the highest stratigraphic occurrence of cretaceous pollen and an anomalously high concentration of the element iridium ir the irz coal is overlain sequentially by the z hfz y w and u coals fossil vertebrates

long chain alkenone patterns in the baltic sea an ocean freshwater transition two different patterns of long chain alkenones are found in surficial sediments of the baltic sea which is the largest brackish water body on earth one pattern occurs in surficial sediments from the western baltic sea where surface water salinitiy is in excess of 7 7 psu it corresponds to the pattern produced by the marine coccolithophorid emiliania huxleyi with a suite of c37 di to tetra unsaturated methyl ketones and c38 di and tri unsaturated methyl and ethyl ketones a second pattern resembling that found in lake sediments in lacking c38 methyl ketones and having distinctly higher c37 4 methyl ketone concentrations dominates in surficial sediments of the eastern and northern baltic sea where salinities are lower than 7 7 psu correspondence of sea surface temperature sst estimates from the u37 and u379 indices using marine calibrations with mean sst in the euphotic zone from july august the main haptophyte growth season is poor thus these indices are not applicable as sedimentary thermometers in surficial sediments of the baltic sea the different patterns may either reflect the salinity dependent occurrence of specific alkenone producers or changes in the alkenone biosynthesis due to physiological stress caused by salinity variations furthermore advection of saline and oxygenated north sea water may transport marine algal material characterized by a marine e huxleyi like alkenone pattern into the western baltic sea thus covering the signature of the local alkenone producers with a baltic sea pattern copyright 2000 elsevier science ltd

a new crocodylian eusuchia from the uppermost cretaceous of alberta canada1 albertosuchus knudsenii gen et sp nov is described on the basis of an incomplete skeleton from the lower part uppermost cretaceous of the scollard formation southern alberta canada it is probably a crocodyloid the only canadian representative of the group and also the sole crocodylian known during the latest cretaceous in canada within the crocodyloidea a knudsenii is one of the most basal forms and shares a sister group relationship with the european genus arenysuchus however it needs to be emphasized that because of its incompleteness phylogenetic relationships proposed here for a knudsenii may change when better preserved specimens are found albertosuchus knudsenii differs from other crocodyloids in having no premaxilla maxillary notch a very short mandibular symphysis with the involvement of the splenial and an extremely deep hypapophysis on the last cervical and anterior dorsal vertebrae the discovery of a knudsenii may expand the geographical range of the crocodyloidea into cana

variability of the arctic front during the last climatic cycle application of a novel molecular proxy in the nordic seas the arctic front af marks the boundary between the waters of the north atlantic drift norwegian current and those of the arctic domain long or short term shifts in the position of the af may affect climate conditions in the northern hemisphere arctic water masses are also the loci of modern open ocean convection hence defining these areas in the past is important for reconstructing and modelling ocean circulation and its variability c37 alkenones are biomarkers for some algae of the class prymnesiophyceae e g coccolitho phorids such as emiliania huxleyi these alga occur in most parts of the oceans in ice free conditions and are found nowadays throughout the nordic seas we have related the sedimentary abundance of the tetraunsaturated c37 alkenone c37 4 to two types of water masses in the nordic seas in locations affected by atlantic water masses percentages of c37 4 are less than 5 whereas in arctic type water masses these increase to more than 5 we propose that this observation can be used as a modern analogue to reconstruct the position of the af in north atlantic quaternary sediments using this novel molecular proxy we can infer that the southward migration of the af in the ne atlantic reached 50 n during the last glacial maximum lgm but perhaps only 60 n during the younger dryas and that ocean conditions free of sea ice prevailed throughout the northern north atlantic in summer

non trionychid turtles from the paleocene of alberta canada turtle fossils of paleocene age have been recovered from four formations in alberta canada the upper paleocene part of the scollard formation the upper paleocene portion of the willow creek formation and the exclusively paleocene porcupine hills and paskapoo formations at least three non trionychid turtle taxa can be recognized definitely present are a generically indeterminate baenid the macrobaenid judithemys backmani and the chelydrid protochelydra zangerli the carapace of a juvenile chelydrid could be either a juvenile of p zangerli or a fourth distinct taxon the macrobaenid j backmani and the chelydrid p zangerli are the most abundant non trionychid turtles from the paleocene of alberta the turtles from the paleocene of alberta differ from those of comparable age in new mexico usa and other more southern localities in the north american western interior in i the presence of macrobaenids and chelydrids and ii the absence of kinosternoids these differences mirror those of the

warming of surface waters in the mid latitude north atlantic during heinrich events 1 during the six heinrich events of the last 70 kyr episodic calving from the circum atlantic ice sheets released large numbers of icebergs into the north atlantic these icebergs and associated meltwater flux are hypothesized to have led to a shutdown of atlantic meridional overturning circulation and severe cooling in large parts of the northern hemisphere however due to the limited availability of high resolution records the magnitude of sea surface temperature sst changes related to the impact of heinrich events on the midlatitude north atlantic is poorly constrained here we present a record of u37k based ssts derived from sediments of integrated ocean drilling project site u1313 located at the southern end of the ice rafted debris ird belt in the midlatitude north atlantic 41 n we demonstrate that all six heinrich events are associated with a rapid warming of surface waters by 2 4 c in a few thousand years the presence of ird leaves no doubt about the simultaneous timing and correlation between rapid surface water warming and heinrich events we argue that this warming in the midlatitude north atlantic is related to a northward expansion of the subtropical gyre during heinrich events as a wide range of studies demonstrated that in the central ird belt heinrich events are associated with low ssts these results thus identify an antiphased seesaw pattern in ssts during heinrich events between the midlatitude warm and northern north atlantic cold this highlights the complex response of surface water characteristics in the north atlantic to heinrich events that is poorly reproduced by freshwater hosing experiments and challenges the widely accepted view that within the ird belt of the north atlantic heinrich events coincide with periods of low ssts

the role of ocean atmosphere reorganizations in glacial cycles abstract a case is made that glacial to interglacial transitions involve major reorganizations of the ocean atmosphere system such reorganizations constitute jumps between stable modes of operation which cause changes in the greenhouse gas content and albedo of the atmosphere only in this way can the rapidity of glacial terminations the hemispheric synchroneity and symmetry of mountain glaciation and the large polar air temperature and dustiness variations be accounted for if these reorganizations are driven in some fashion by orbitally induced seasonal insolation changes then the connection between insolation and climate is most likely through impacts of fresh water transport on the ocean s salinity distribution

alkenones alkenoates and organic matter in coastal environments of nw scotland assessment of potential application for sea level reconstruction reconstruction of late quaternary sea level history in areas of glacioisostatic uplift often relies on sediment archives from coastal isolation basins natural coastal rock depressions previously isolated from or connected to the sea at different times proxy indicators for marine brackish or lacustrine conditions combined with precise dating can constrain the time when the sea crossed the sill threshold and isolated or connected the basin the utility of isolation basins in investigations of sea level change is well known but investigations have been mostly limited to microfossil proxies the application of which can be limited by preservation and nonanalog problems here we investigate the potential of long chain alkenones alkenoates and bulk organic parameters toc corg n for reconstructing past sea level changes in isolation basins in nw scotland we analyze organic biomarkers and bulk parameters from both modern basins at different stages of isolation from the sea and fossil basins with sea level histories reconstructed from established proxies logit regression analysis was employed to find which of the biomarker metrics or bulk organic measurements could reliably characterize the sediment samples in terms of a marine brackish or isolated lacustrine origin the results suggested a good efficiency for the alkenone index c37 4 at predicting the depositional origin of the sediments this study suggests that alkenones could be used as a novel proxy for sea level change in fossil isolation basins especially when microfossil preservation is poor

surface water temperature salinity and density changes in the northeast atlantic during the last 45 000 years heinrich events deep water formation and climatic rebounds we developed a new method to calculate sea surface salinities sss and densities ssd from planktonic foraminiferal 18o and sea surface temperatures sst as determined from planktonic foraminiferal species abundances sst sss and ssd records were calculated for the last 45 000 years for biogeochemical oceanic flux study bofs cores 5k and 8k recovered from the northeast atlantic the strongest feature is the dramatic drop in all three parameters during the heinrich ice rafting events we modelled the possibility of deepwater formation in die northeast atlantic from the ssd records by assuming that the surface waters at our sites cooled as they flowed further north comparison with modelled north atlantic deepwater densities indicates that there could have been periods of deepwater formation between 45 000 and 30 000 14c years b p interrupted by iceberg meltwater input of heinrich event 3 and 4 at 27 000 and 38 000 14c years b p and during the holocene no amount of cooling in the northeast atlantic between 30 000 and 13 000 years could cause deep water to form because of the low salinities resulting from the high meltwater inputs from icebergs our records indicate that after each heinrich event there were periods of climatic rebound with milder conditions persisting for up to 2000 years as indicated by the presence of warmer and more saline water masses after these warm periods conditions returned to average glacial levels these short term cold and warm episodes in the northeast atlantic are superimposed on the general trend towards colder conditions of the last glacial maximum lgm heinrich event 1 appears to be unique as it occurs as insolation rose and was coeval with the initial melting of the fennoscandian ice sheet we propose that meltwater input of heinrich event 1 significantly reduced north atlantic deep water formation reducing the heat exchange between the low and high latitudes thus delaying deglaciation by about 1500 radiocarbon years 2000 calendar years

the last glacial interglacial transition lgit in the western mid latitudes of the north atlantic abrupt sea surface temperature change and sea level implications abstract high resolution reconstructions of sea surface temperature uk 37 sst coccolithophore associations and continental input total organic carbon higher plant n alkanes n alkan 1 ols in core d13882 from the shallow tagus mud patch are compared to sst records from deep sea core md03 2699 and other western iberian margin cores results reveal millennial scale climate variability over the last deglaciation in particular during the lgit in the iberian margin heinrich event 1 h1 and the younger dryas yd represent two extreme episodes of cold sea surface condition separated by a marine warm phase that coincides with the bolling allerod interval b a on the neighboring continent following the yd event an abrupt sea surface warming marks the beginning of the holocene in this region ssts recorded in core d13882 changed however faster than those at deep sea site md03 2699 and at the other available palaeoclimate sequences from the region while the sst values from most deep sea cores reflect the latitudinal gradient detected in the iberian peninsula atmospheric temperature proxies during h1 and the b a the tagus mud patch core d13882 experienced colder ssts during both events this is most certainly related to a supplementary input of cold freshwater from the continent to the tagus mud patch a hypothesis supported by the high contents of terrigenous biomarkers and total organic carbon as well as by the dominance of tetra unsaturated alkenone c37 4 observed at this site the comparison of all western iberia sst records suggests that the sst increase that characterizes the b a event in this region started 1000 yr before meltwater pulse 1a mwp 1a and reached its maximum values during or slightly after this episode of substantial sea level rise in contrast during the yd holocene transition the sharp sst rise in the tagus mud patch is synchronous with meltwater pulse 1b the decrease of continental input to the mud patch confirms a sea level rise in the region thus the synchronism between the maximum warming in the mid latitudes off the western iberian margin the adjacent landmasses and greenland indicates that mwp 1b and the associated sea level rise probably initiated in the northern hemisphere rather than in the south

climatic dependence of the organic matter contributions in the north eastern norwegian sea over the last 15 000 years abstract lipids are used for the evaluation of the different organic matter contributions in the north eastern norwegian sea m23258 site 75 n 14 e over the last 15 000 years development of a mass balance model based on the down core quantification of the c 37 alkenones the odd carbon numbered n alkanes a odd and the unresolved complex mixture of hydrocarbons ucm has allowed three main organic matter inputs involving marine continental and ancient reworked organic matter to be recognized the model shows good agreement between measured and reconstructed toc values similarly a strong parallelism is observed between predicted components such as marine toc and carbonate content which was determined independently representation of the model results within a time scale based on 15 ams 14 c measurements shows that the main changes in organic matter constituents are coincident with the major climatic events of the last 15 000 years thus the predominance of reworked organic matter is characteristic of termination ia up to 70 continental organic matter was dominant during the bolling allerod b a and younger dryas yd periods about 85 and a strong increase of marine organic matter occurred in the holocene between 50 and 75 this agreement reflects the main hydrographic changes that determined the deposition of sedimentary materials between 0 and 15 cal ka ice rafted detritus from the barents continental platform ice melting waters from the arctic fluvial system discharging into the barents sea and dominance of north atlantic currents respectively in this respect the high resolution down core record resulting from the mass balance and lipid measurements allows for the identification of millennial scale events such as the increase of reworked organic matter at the final retreat of the barents ice sheet at the end of the deglaciation period termination ib

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

a new crocodylian archosauria from the basal paleocene of the red deer river valley southern alberta borealosuchus griffithi sp nov is described on the basis of an incomplete skeleton from the basal paleocene southern alberta this new species records one of a few basal cenozoic occurrences o

distributions of long chain alkenones and alkyl alkenoates in marine surface sediments from the north east atlantic abstract the abundances of long chain alkenones and alkyl alkenoates are reported for a suite of surface sediments from the ne atlantic 0 75 n despite the differing conditions of their biologies and differing extents of water column degradation and of early diagenesis in the sediments the degree of unsaturation of the alkenones e g the u 37 k parameter and the relative proportion of alkyl alkenoates to alkenones display linear correlations with average temperature for surface waters warmer than 5 c there is evidence that the chain length distribution of the alkenones and of the ratio between the ethyl and methyl c 38 alkenones are species dependent which would enable their use as chemotaxonomic tools

expansion of subarctic water masses in the north atlantic and pacific oceans and implications for mid pleistocene ice sheet growth 1 past surface ocean circulation changes associated with the mid pleistocene transition 0 9 0 6 ma were reconstructed in the northern north atlantic odp 983 and the northwest pacific odp 882 using proxies for subarctic subpolar water mass distributions c37 4 alkenone and sea surface temperature u37 both sites experienced a secular expansion of subarctic waters from 1 15 ma spanning both glacial and interglacial intervals after 0 9 ma low c37 4 at site 983 records a northward retreat of subarctic waters during interglacials in the atlantic while continued high glacial c37 4 indicate extensive subarctic waters during glacial maxima associated with the development of the larger late pleistocene ice sheets in contrast a secular decline in c37 4 occurred at site 882 from 0 9 to 0 5 ma marking a more gradual retreat of subarctic conditions in the pacific it is proposed that the expansion of subarctic waters between 1 15 and 0 9 ma exerted negative feedbacks to the moisture supply to the ice sheet source regions and may account for the apparent delayed ice sheet response to atmosphere ocean circulation changes associated with the mid pleistocene transition that began as early as 1 2 ma

evidence for a warm last glacial maximum in the nordic seas or an example of shortcomings in uk 37 and uk 37 to estimate low sea surface temperature the occurrence of ice free conditions in the nordic seas during the last glacial maximum has been demonstrated using microfossil and biomarker approaches an accurate picture of the prevailing oceanographic conditions may be more difficult to ascertain thus uncertainties for most proxies increase at the cold extreme of temperature calibrations and glacial sediments contain small amounts of microfossils and biomarkers here we discuss sea surface temperature estimates derived from alkenone indices for the last glacial maximum in the nordic seas that provide a surprising scenario where surface temperatures were warmer than at present we conclude that the uk37 and uk37 estimates may not be interpreted in terms of sea surface temperature as several factors may have conspired to bias the molecular signal however using an alternative index based on the abundance of the c37 4 alkenone we estimate a maximum temperature of 6 c

recent postglacial rebound gravity change and mantle flow in fennoscandia summary the recent postglacial rebound of fennoscandia is investigated using sea level data levelling data and gravity data in particular an analysis is made of the repeated data obtained hitherto on the fennoscandian land uplift gravity line along latitude 63 methods for this analysis include an iterative procedure for computing the relation between gravity change and absolute land uplift the mass flow parameter and the geoid rise the remaining land uplift is also estimated the mass flow parameter c is used to characterize the relation between additional mass and additional volume due to rebound it is a number between 0 and 1 1 corresponding to full inflow of mantle below the rising crust and 0 to no inflow but some kind of decompression the main result is that c is significantly different from 0 at the 99 per cent level we find c 0 8 this means that models proposed of the present uplift based on pure decompression must be ruled out and that a viscous inflow of mantle is a necessary part of the ongoing uplift process on the other hand this process might be more complicated than a pure viscous flow

surface deformation caused by pressure changes in the fluid core pressure load love numbers are presented for calculating the mantle deformation induced by the variation of the pressure field at the core mantle boundary cmb we find that the cmb geostrophic pressure fields derived from frozen flux core surface flow estimates at epochs 1965 and 1975 produce a relative radial velocity rrv field in the range of 3mm decade with uplift near the equator and subsidence near the poles the contribution of this mechanism to the change in the length of day i o d is small about 2 3 x 10 2 ms decade the contribution to the time variation of the ellipticity coefficient j 2 is more important about 1 3 x x 10 11 yr

controls on alkenone unsaturation ratios along the salinity gradient between the open ocean and the baltic sea abstract alkenone unsaturation ratios of sedimentary lipids are used as a geochemical proxy for sea surface temperatures and interest is growing in their potential as indicators of different water masses and possibly of salinity we analyzed the abundance of unsaturated c37 to c38 ketones in lipid extracts of 57 surface sediment 0 1 cm samples along a salinity gradient from 8 to 33 psu in the transition from the skagerrak to the baltic sea nw europe in addition to surface sediments we analyzed alkenones in suspended particulate matter at 13 stations over a gradient in salinity from 25 to 33 psu during a bloom of the coccolithophore emiliania huxleyi alkenones were detected in all samples suspended matter and sediment with variable contributions of the tetra unsaturated c37 alkenone compound c37 4 range from 2 to 10 of total c37 alkenone content comparing the alkenone unsaturation index u37k and c37 4 data to climatological sea surface temperature and sea surface salinity data sets revealed that sst estimated from u37k of saline end members samples from the skagerrak is in the general range of modern sst during bloom periods of haptophytes at salinities below 30 psu c37 4 increases to above 5 and the unsaturation ratios cease to be related to climatological annual or seasonal sea surface temperatures on the other hand the c37 4 appears to be inversely and significantly correlated to salinity highest c37 4 proportions in the inner baltic sea are caused by an unidentified organism but in the transition area at salinities down to 10 psu the producer apparently is e huxleyi the suspended matter data together with those from the water column support the hypothesis of changing biosynthesis of alkenones under salt stress by the coccolithophore e huxleyi but constrain the maximum of c37 4 attributable to salt stress to 10 of all c37 alkenones

vertical deformation and absolute gravity summary crustal deformation in the greenland and antarctic areas is strongly influenced by both postglacial rebound and contemporary mass redistribution we explore the relationship between the displacement field and the gravitational disturbance for a viscoelastic maxwell earth with an arbitrary radial viscosity profile we seek to determine whether the effects of viscous relaxation in the memory of surface mass change can be separated from the effects of present day mass variation by combined measurements of vertical displacement and absolute gravity when the viscosity profile in the earth s interior is unknown our conclusion is positive specifically the non elastic effects can be reduced substantially by combined measurements of displacement and gravity change for a maxwell viscoelastic earth regardless of its radial viscosity profile the underlying physics has nothing to do with the mathematical structure of viscous relaxation modes rather it is due to the fact that the non elastic response of a maxwell earth is nearly incompressible

tectonic stratigraphic and sedimentologic significance of a regional discontinuity in the upper judith river group belly river wedge of southern alberta saskatchewan and northern montana the lithostratigraphic interval between the taber and lethbridge coal zones in the upper portion of the nonmarine judith river group of southeastern alberta is divisible into two lithostratigraphic units separated by a regionally extensive and diachronous discontinuity the lower unit referred to here as the oldman formation is characterized by very fine grained to fine grained sandstones that contain fewer than 2 volcanic rock fragments sandstone bodies with numerous sets of horizontally stratified sandstone showing little or no evidence of lateral accretion siliceous paleosols ganisters and a relatively high gamma ray signal in the upper half of the formation the oldman formation comprises deposits of a low sinuosity perhaps ephemeral fluvial system that originated in the southern cordillera of canada and northern montana and flowed northeastward perpendicular to the axis of the alberta basin the upper unit is assigned to a new formation the dinosaur park formation and is characterized by

a singularity free approach to post glacial rebound calculations calculating the post glacial response of a viscoelastic earth model using the exponential decay normal mode technique leads to intrinsic singularities if viscosity varies continuously as a function of radius we develop a numerical implementation of the complex real fourier transform crft method as an accurate and stable procedure to avoid these singularities using crft we investigate the response of a set of maxwell earth models to surface loading we find that the effect of expanding a layered viscosity structure into a continuously varying structure is to destroy the modes associated with the boundary between layers horizontal motion is more sensitive than vertical motion to the viscosity structure just below the lithosphere horizontal motion is less sensitive to the viscosity of the lower mantle than the vertical motion is when the viscosity increases at 670 km depth by a factor of about 60 the response of the lower mantle is close to its elastic limit any further increase of the viscosity contrast at 670 km depth or further increase of viscosity as a continuous function of depth starting from 670 km depth is unlikely to be resolved

northeast atlantic sea surface circulation during the past 30 10 14c kyr b p a study was made of three cores from the faeroe shetland gateway based on planktonic foraminifera oxygen isotopes accelerator mass spectrometry 14c dates magnetic susceptibility and counts of ice rafted debris ird the data covering the period 30 10 ka show that during the last glacial maximum the arctic front occupied a position close to the faeroes allowing a persisting inflow of atlantic surface water into the faeroe shetland channel the oceanographic environment during deposition of two ird layers is influenced by atlantic surface water masses during the lower ird layer with transport of icebergs from n nw polar surface water conditions prevailed only during deposition of the upper ird layer there is no indication of surface meltwater influence in the region during the deglaciation but there is a persistent influence of atlantic surface water masses in the region thus we conclude that during almost the entire period 30 10 ka the faeroe shetland channel was a gateway for transport of atlantic surface water toward the norwegian sea

abrupt variability of the last 24 ka bp recorded by coccolithophore assemblages off the iberian margin core md03 2699 a high resolution coccolithophore study allowed reconstructing sea surface conditions during the last 24 ka bp off the iberian margin variations in nannoplankton accumulation rate cold water species florisphaera profunda umbilicosphaera sibogae and coccolithus pelagicus ssp azorinus trends suggest the occurrence of substantial changes in surface water dynamics palaeoproductivity shows changes during the glacial and the interglacial transition from intense glacial upwelling to persistent interglacial stratification a drastic productivity decline occurred between 18 and 13 ka bp related to the arrival of subpolar waters indicated by the presence of the subarctic subspecies c pelagicus pelagicus and increased percentages of tetra unsaturated alkenones abrupt variability at core md03 2699 during the last 24 ka bp was observed in palaeoproductivity and sea surface temperatures proxies increases of reworked species fluxes were observed during the last glacial maximum and during the transition to the holocene likely connected to turbidity currents and or contourites formed by mediterranean outflow intensification in addition c pelagicus ssp pelagicus presence gephyrocapsa muellerae and tetra alkenone percentages reveal rapid coolings coeval with the holocene bond cycles and rapid climate coolings recognized for the northern hemisphere between 11 02 and 1 7 ka bp and associated with subpolar water arrival at the site copyright 2013 john wiley sons ltd

combined dna and lipid analyses of sediments reveal changes in holocene haptophyte and diatom populations in an antarctic lake preserved ribosomal dna of planktonic phototrophic algae was recovered from holocene anoxic sediments of ace lake antarctica and the ancient community members were identified based on comparative sequence analysis the similar concentration profiles of dna of haptophytes and their traditional lipid biomarkers alkenones and alkenoates revealed that fossil rdna also served as quantitative biomarkers in this environment the dna data clearly revealed the presence of six novel phylotypes related to known alkenone and alkenoate biosynthesizing haptophytes with isochrysis galbana uio 102 as their closest relative the relative abundance of these phylotypes changed as the lake chemistry particularly salinity evolved over time changes in the alkenone distributions reflect these population changes rather than a physiological response to salinity by a single haptophyte using this novel paleo ecological approach of combining data from lipid biomarkers and preserved dna we showed that the post glacial development of ace lake from freshwater basin to marine inlet and the present day lacustrine saline system caused major qualitative and quantitative changes in the biodiversity of the planktonic populations over time

the period and q of the chandler wobble summary we have extended our calculation of the theoretical period of the chandler wobble to account for the non hydrostatic portion of the earth s equatorial bulge and the effect of the fluid core upon the lengthening of the period due to the pole tide we find the theoretical period of a realistic perfectly elastic earth with an equilibrium pole tide to be 426 7 sidereal days which is 8 5 day shorter than the observed period of 435 2 day using rayleigh s principle for a rotating earth we exploit this discrepancy together with the observed chandler q to place constraints on the frequency dependence of mantle anelasticity if q in the mantle varies with frequency u as u between 30 s and 14 months and if q in the lower mantle is of order 225 at 30 s we find that 0 04 5 a 5 0 1 1 if instead q in the lower mantle is of order 350 near 200 s we find that 0 11 5 a 0 19 in all cases these limits arise from exceeding the 68 per cent confidence limits of 2 6 day in the observed period since slight departures from an equilibrium pole tide affect the q much more strongly than the period we believe these limits to be robust

alkenone distributions in the north atlantic and nordic sea surface waters 1 the c37 c39 alkenones were quantified in suspended particulate matter obtained from the surface waters of the north atlantic including the nordic seas over a temperature range of 4 20 c u37k values were linearly correlated to temperature over the entire range covered by our data set i e 4 20 c u37k 0 027t 0 036 r2 0 97 the compilation of water column data from the atlantic pacific and southern ocean and mediterranean sea suggests that the linear model may not be the best function for fitting u37k and in situ temperature values it also shows that suspended matter data from warm waters t 20 c are still needed to constrain the equation of the global curve high abundances of c37 4 were found in the coldest polar waters around 4 c c37 4 represented up to 35 a value that dropped to zero at temperatures above 10 c values of c37 4 were linearly correlated to temperature c37 4 3 7t 43 7 r2 0 50 and salinity c37 4 48 1s 1691 r2 0 78 further investigations from other oceanic basins are necessary to confirm these findings

introduction to the special issue commemorating the 30th anniversary of the royal tyrrell museum of palaeontology with a summary of the museum s early history and its research contributions located just west of drumheller in southern alberta canada the royal tyrrell museum of palaeontology rtmp is nestled among outcrops of the upper cretaceous horseshoe canyon formation exposed along the red deer river valley fig 1 since it officially opened on 25 september 19851 the museum has become one of alberta s must see tourist attractions a significant contributor to the local economy and earned an international reputation for the quality of its palaeontological collections and the research conducted by its scientists the rtmp is unique within canada in being the only government supported museum dedicated to palaeontology and it is one of the few such institutions in the world fig 1 the royal tyrrell museum of palaeontology a front of museum and main entrance circa 2010 looking westwards and with horizontal beds of the upper cretaceous horseshoe canyon formation exposed in the walls of the red deer river valley in the distance b aerial photograph oblique angle and looking to the north northeast the museum sits on top of the number 7 coal seam sensu gibson 1977 and at the base of the horsethief member of the horseshoe canyon formation d a eberth pers comm 2015 that stratigraphic position correlates with an age of about 71 5 ma i e late campanian and lies within the upper part of the edmontosaurus regalis pachyrhinosaurus canadensis dinosaur assemblage zone see eberth et al 2013 fig 6 c the iconic running theropod logo that until recently graced the exterior of the museum below a life sized tyrannosaurid sculpture by brian cooley one of many such sculptures by cooley that have been featured at the museum since its opening in 1985 and with the education wing opened in 2003 as the atco tyrrell learning centre in the background d the cretaceous alberta life sized diorama opened in 2007 an example of a rtmp exhibit that relies heavily on discoveries and interpretations by museum researchers in this case work done in the albertosaurus bonebed and at other localities throughout the horseshoe canyon formation all photographs courtesy of the royal tyrrell museum of palaeontology this special issue of the canadian journal of earth sciences presents a collection of papers commemorating the rtmp s 30th or pearl anniversary our rationale for doing a 30th anniversary volume was two fold first it is an opportunity to showcase the breadth of research conducted by current and former museum scientists as well as by some colleagues having a history of collaboration with the rtmp the 13 invited papers included in this volume are a mix of review and original research papers all thematically focused on the geology and palaeontology of alberta to varying degrees each contribution is the result of work supported by the rtmp and relies on specimens housed in the museum s collections second the 30th anniversary is an opportunity to reflect on the rtmp s history and its research program as is typical for most institutions the rtmp has done little to formally document its own history this year likely will be the last major milestone for which the original generation of museum staff are still working and available to share their recollections about the museum fieldwork and research already deaths and departures have winnowed away part of the original

response of the high latitude northern hemisphere to orbital climate forcing evidence from the nordic seas sediment cores from the nordic greenland iceland and norwegian seas provide evidence that this area acts as an initial responder to the forcing effect of orbitally driven changes in insolation on the climate system as postulated by j imbrie et al the 18 o record of the cores documents a widespread initial deglacial signal in the area between 15 and 13 ka 1000 yr before other deglacial signals from other parts of the northern hemisphere an even earlier meltwater event has been dated to 16 090 185 yr b p north of iceland at the initial rise of northern hemisphere insolation after the last glacial maximum during the period with lowered surface salinities the nordic seas were still cold reconstructions of the surface water conditions of the area show that as the summer insolation values of the northern hemisphere reached half of maximum values a sea ice free corridor opened along norway at 13 4 ka nearly contemporaneous fluctuations of the polar front and the sea surface temperatures with the insolation changes indicate that the nordic seas are very sensitive to insolation forcing especially in regions close to the sea ice margin a decrease in sea surface temperature and an increase in the areal extent of sea ice cover since 7 ka indicate that the area is currently on the way to glacial conditions supporting the predictions made earlier by j imbrie et al

iberian margin sea surface temperature during mis 15 to 9 580 300 ka glacial suborbital variability versus interglacial stability 1 past sea surface water conditions of the western iberian margin were reconstructed based on biomarker analyses of a marine deep sea core md03 2699 from the estremadura spur north off lisbon providing new insights into orbital and suborbital scale climate variability between marine isotope stage mis 15 to mis 9 580 to 300 ka we use biomarker based proxy records such as the alkenone unsaturated index to estimate sea surface temperature sst the total alkenone concentration to reconstruct phytoplankton productivity and terrestrial biomarkers to evaluate the continental input the results extend the existing biomarker record namely the sst for the iberian margin back to the sixth climatic cycle 580 ka a general trend of stable interglacials contrasts with glacial periods and glacial inceptions which are marked by high frequency variability thus several short lived climatic coolings were identified by large sst decreases the occurrence of ice rafted detritus and high percentages of the tetraunsaturated alkenone c37 4 some of these events were extremely cold and similar in their general trends to the well known heinrich events of the last glaciation we identified eight heinrich type events between 580 and 300 ka the general deglaciation pattern detected between mis 15 and mis 9 is similar in their general trends to that characterizing the more recent climatic cycles i e marked by two coolings separated by a short warming episode which may reflect the southward northward and southward migration of the polar front

summary of fossil vertebrate taxa named by richard c fox with an annotated list of taxa named between 1962 and 2012 and new photographs for non mammalian therapsid and mammalian holotypes erected between 1968 and 1994 beginning in 1962 and extending to the present richard c fox and colleagues have named 87 species of fossil vertebrates 1 fish 4 amphibians 2 choristoderes 12 lizards 1 crocodile 1 dinosaur 2 pelycosaurs 2 non mammalian therapsids and 62 mammals and numerous new supraspecific taxa virtually all of these species continue to be accepted although the higher level assignments of several have been altered the vast majority of the named species were founded on specimens collected during the mid 1960s to early 2000s by field parties under fox s direction from the late cretaceous late santonian to late maastrichtian and paleocene of alberta and saskatchewan canada and that are housed at the university of alberta laboratory for vertebrate paleontology here we present i an annotated list of all fossil vertebrate species named by richard fox between 1962 and 2012 ii updated information on the stratigraphic nomenclature and age estimates for the eight localities in alberta that yielded ho

sunosuchus junggarensis sp nov archosauria crocodyliformes from the upper jurassic of xinjiang people s republic of china a new species of crocodyliformes sunosuchus junggarensis is established on the basis of six individuals from the upper jurassic of the junggar basin xinjiang northwest china it differs from other species of sunosuchus primarily in having a dorsoventrally depressed supraoccipital that in occipital view lacks a median crest a frontal that is ridged anteriorly a distinct depression distal to the foramen aereum on the dorsal surface of the quadrate and an elongate undivided maxillary depression cranial ontogenetic variation in s junggarensis is discussed sunosuchus is probably a goniopholidid crocodyliform it is distinguished from other genera of the goniopholididae by a narrow and elongate snout a small skull table a partially ridged frontal a pair of anteriorly located anterior palatal fenestrae a lateroventrally mediodorsally expanded retroarticular process some enlarged pits on the frontal and an elongate mandibular symphysis with the splenial forming a small part of it sunosuchus

paleoceanographic reconstructions of surface ocean conditions in the greenland iceland and norwegian seas through the last 14 ka based on diatoms prior reconstructions of the last glacial maximum and the holocene did not include detailed paleoclimate data from the greenland iceland and norwegian gin seas which cover sensitive areas for oceanographic boundaries sea ice distribution and deep water formation in order to fill this gap we studied nine well dated sediment cores from this area and reconstructed the paleoceanographic conditions of the surface gin seas at 2000 year intervals since 13 400 bp based on the diatom record results show that a n s extending sea ice free corridor had opened along norway already at 13 400 bp indicating a northward flow of a branch of the north atlantic drift possibly caused by a change in the jet stream flow due to the decreased height of the north american ice sheet a major change of climatic conditions occurred over the gin seas as the insolation anomaly reached its maximum around 9000 bp when the sea ice cover and the oceanic fronts retreated to a northwesterly position along greenland and the ocean temperatures rose the first half of the holocene is recorded as the warmest period during the last 13 400 bp in the gin seas the duration of this climatic optimum decreased both toward the north and toward the margins of the area the second half of the holocene is characterized by a cooling trend in step with the decreasing insolation these results support the proposal of imbrie et al 1992 that the gin seas region acts as an initial responder to insolation changes

a radiometric age for the cretaceous tertiary boundary based upon k ar rb sr and u pb ages of bentonites from alberta saskatchewan and montana bentonites associated with coal seams at the north american cretaceous tertiary k t boundary in the red deer valley of alberta in the frenchman valley of saskatchewan and near hell creek montana were dated by the k ar rb sr and u pb methods based upon palynological stratigraphic correlation and the presence of a sharp iridium anomaly the three sampled bentonite horizons all occur less than 1 m above the established k t boundary there is evidence of possible systematic errors giving dating results outside nominal statistical error values despite possible constant errors the weighted mean of nine average dates is calculated as 64 3 1 2 ma 2 standard deviation an unweighted averaging produces a grand mean age of 64 4 1 2 ma

interhemispheric appraisal of the value of alkenone indices as temperature and salinity proxies in high latitude locations alkenone sediment data from the nordic seas and north atlantic are compared to those from sikes et al 1997 for the southern ocean to evaluate further uk37 and uk37 as proxies to estimate cold temperatures 10 c and the effect of salinity and temperature in the relative abundance of 37 4 to the total abundance of c37 alkenones 37 4 uk37 and uk37 are found to be equally viable as proxies but there are significant regional differences in their cold temperature dependence the measurement of 37 4 in cores from the north atlantic region can be used to identify situations when uk37 is not a reliable paleothermometer variations in salinity are probably responsible for changes in the sedimentary record of 37 4 and a preliminary calibration has been obtained for 37 4 f salinity this new relationship should be further confirmed through field or laboratory experiments but it paves the way to derive a molecular proxy to reconstruct paleosalinity in surface waters