the muirkirk mammoth a late pleistocene woolly mammoth mammuthus primigenius skeleton from southern ontario canada abstract the muirkirk mammoth found in 1895 2 4 km northeast of the village of muirkirk in southern ontario is the most complete woolly mammoth mammuthus primigenius skeleton known from canada approximate tusk measurements and extreme wear on the sixth molars indicate it is best referred to an old male its geological age was controversial because the first two holocene bone collagen radiocarbon dates were derived evidently from contaminated samples three new radiocarbon dates on carefully selected bone and ivory are close averaging 12 190 bp and indicate that this mammoth died before the close of the wisconsinan glaciation and near the time of extinction of woolly mammoths in this part of north america its assignment to regional pollen subzone 1b suggests that like the rostock mammoth of similar age from southern ontario it lived in a tundra woodland environment the highgate mastodon mammut americanum and giant beaver castoroides ohioensis found 4 km away and also assigned to pollen subzone 1b suggests that some spruce wetlands characterised the tundra woodland environment and that perhaps woolly mammoths and american mastodons lived almost side by side in southern ontario about12 000 radiocarbon years or 14 000 calendar years ago the muirkirk mammoth is discussed in relation to the dispersal history of woolly mammoths

origin and causes of the mammoth steppe a story of cloud cover woolly mammal tooth pits buckles and inside out beringia to account for the vastness of the northern arid steppes during glacial episodes i propose the proximate key variable was simply frequent clear skies this hitherto under emphasized point is the hub which best explains many questions low maritime cloud cover best accounts for today s tundra and in a related way the cloudy polar front accounts for the whole of the taiga even during glacial maxima the proximity of the sea to the bering isthmus created intermittent maritime cloud cover this regional cloud cover produced an ecological interruption or buckle of the arid steppe belt while this beringian mesic buckle did not serve as an intercontinental ecological barrier to most steppe adapted species it does seem to have limited the distributions of woolly rhinos camels american kiangs short faced bears badgers and some others at the beginning of the holocene this narrow refugium seems to have been a source of some mesic adapted species which colonized westward into the now tundra vegetation of northern asia and eastward into northern north america this holocene expansion from a limited and regional pleistocene refugium created our present misconceptions about beringia the mid strait mesic ecological conditions were the exception to the more extensive arid adapted communities of the mammoth steppe 2000 published by elsevier science ltd all rights reserved

paleoclimatic implications of a late wisconsinan insect assemblage from rostock southwestern ontario the rostock site is situated in a peat covered wetland where fragments of a mammoth mammuthus primigenius were unearthed in 1982 excavation showed a descending sequence of peat silty marl gravel clayey silt and till approximately 300 kg of sediment was taken from the section for pollen invertebrate and geochemical analyses the peat marl transition is believed to be approximately contemporaneous with the spruce pine transition in southern ontario ca 10 600 years bp a date of 10 790 150 years bp on collagen from mammoth tusk fragments recovered from the same level substantiates this inference insects especially coleoptera were common throughout the marl and represent at least 2000 individuals from 16 different families on the basis of beetle ecologies and modern distributions the marl was subdivided into lower and upper horizons the lower horizon contains many species that are today restricted to western and northern north america they are typical residents of the northern boreal fore

modeling the oxygen isotopic composition of the north american ice sheet and its effect on the isotopic composition of the ocean during the last glacial cycle contribution to the change of seawater d 18 o dw between the last glacial maximum lgm and the holocene and to evaluate the effect of nonequilibrium isotopic composition of the nais on the relationship between ice volume variations and the ocean isotopic enrichment the enrichment due to the nais at the lgm was 0 63 corresponding to 60 of the lgm sea level lowstand and to a mean d 18 o of the nais of approximately 31 the modeled nais volume variations and the induced dw changes over the past 120 000 years indicated no significant time lag the inaccuracy associated with linearly inferring ice volume variations from dw changes was generally less than 10 citation sima a a paul m schulz and j oerlemans 2006 modeling the oxygen isotopic composition of the north american ice sheet and its effect on the isotopic composition of the ocean during the last glacial cycle geophys res lett 33 l15706 doi 10 1029 2006gl026923

a mammoth mammuthus primigenius tooth from late wisconsin deposits near embden north dakota and comments on the distribution of woolly mammoths south of the wisconsin ice sheets a well preserved third molar of a woolly mammoth mammuthus primigenius was recovered from sand and gravel forming the highest herman prominent strandline of lake agassiz near embden in western cass county north dakota the herman strandline is estimated to have formed about 11 500 years bp and presumably the tooth is of similar age perhaps the animal lived in a tundra like area near the lake agassiz shoreline additional evidence suggests that woolly mammoths occupied a tundra like range south of the wisconsin ice sheets extending from southern british columbia to the atlantic continental shelf off virginia

paradigms and proboscideans in the southern great lakes region usa abstract thirteen new chronometric dates for illinois proboscideans are considered in relation to well dated pollen records from northeastern and central illinois these dates span an interval from 21 228 to 12 944 cal bp when compared to pollen spectra it is evident that mammut americanum inhabited spruce picea and black ash fraxinus nigra forest during the bolling allerod 14 700 12 900 cal bp and early younger dryas 12 900 11 650 cal bp chronozones both mammuthus jeffersonii and mammuthus primigenius inhabited spruce dominated open woodland during the oldest dryas chronozone while m primigenius persisted in a forest of predominantly black ash during the allerod chronozone a newly discovered specimen from lincoln il clarifies the taxonomic distinction between m primigenius and m jeffersonii hitherto a paradigm of proboscidean succession during the full to late glacial periods was based on the vegetation succession of steppe tundra like vegetation to spruce forest to spruce deciduous forest the presumed proboscidean succession was that of cold dry steppe adapted m primigenius succeeded by more mesic tolerant m jeffersonii that in turn was succeeded by the wet forest adapted m americanum reported data do not support this view and indicate a need for re evaluation of assumptions of proboscidean ecology and history e g the environmental tolerances and habits of m primigenius in regions south of 55 n and its dynamic relationship with other proboscidean taxa

pliocene and early pleistocene paleoenvironmental conditions in the pannonian basin hungary slovakia stable isotope analyses of fossil proboscidean and perissodactyl teeth abstract stable carbon and oxygen isotope values of structural carbonate 13c 18oco3 and phosphate 18opo4 in bio apatite were measured for fossil mammalian teeth from slovakia and hungary oxygen isotope compositions of enamel provide new quantitative records of the pliocene and early pleistocene paleoclimate in the pannonian basin pb the 18opo4 values were used to study the temporal variations in the oxygen isotope compositions of precipitation and the changes in temperature over the pb the new o isotope data suggest that surface air temperatures between 4 5 and 2 0 ma were 1 to 4 c warmer with about 700 mm yr more precipitation compared to the present c isotope analyses of samples from proboscideans anancus sp mammut sp and perissodactyls stephanorhinus sp tapirus sp from the pliocene mn15 mn16 and early pleistocene mn17 suggest that they were primarily c3 browsers the mean 13c value is high at 4 5 to 3 7 ma mn14 15 during the pliocene warm period and decreases at about 3 5 to 3 0 ma mn16 mid pliocene warm period with the onset of more humid conditions in europe the 13c values return to higher values from 2 5 ma onwards mn17 most likely reflecting more arid conditions as a consequence of the onset of the northern hemisphere glaciation

the isotopic ecology of late pleistocene mammals in north america part 1 florida abstract mammoths and mastodons are common in pleistocene deposits yet these proboscideans and many other animals disappeared suddenly 10 000 years ago in this study we reconstruct the diets of proboscideans and associated mammals through isotopic analysis of carbonate in tooth enamel apatite in order to test nutritional hypotheses for late pleistocene extinction we analyzed specimens from six sites in florida ranging from full glacial 21 000 bp to late glacial 14 750 to 10 000 bp age the oxygen isotope composition of mammalian apatite covaries with meteoric water composition which in turn varies with climate consequently oxygen isotope analysis can be used to assess the potential for time averaging or mixing of specimens from different geographic regions within fossil assemblages the carbon isotope composition of an herbivore is controlled by the isotopic composition of the plants that it ingests carbon isotope analysis reveals that mastodons ate chiefly c3 plants presumably trees shrubs and herbs whereas mammoths consumed chiefly c4 grass several nutritional hypotheses for late pleistocene extinction entail the assumption that extinct taxa had specialized diets the resource partitioning and focused feeding preferences of florida s proboscideans corroborate this assumption but they do not in themselves prove that nutritional stress was the cause of the late pleistocene extinction

erratum glacial lake arkona whittlesey transition near leamington ontario geology plant and muskox fossils proglacial subaquatic fans between leamington and colchester essex county ontario were deposited in glacial lake maumee at the end of the port bruce stade by ice retreating northward some fans were buried by till and glaciolacustrine materials one fan surface northwest of leamington was only modified by lake current that transgressed and regressed over it an aggregate excavation bondi site exists within the surface of this fan we describe the sedimentology of the site that provides evidence for fan and overlying bar deposits lake levels fell to the levels of lakes arkona 216 m and ypsilanti 122 m following the deposition of the fans large terrestrial areas supported plants and animals their presence is recorded at the bondi site by a single bone and several organic mats recovered from the fan and bar sediment contact at two separate exposures radiocarbon dates on the bone of 13 410 100 bp to 1803 organic material dates of 13 225 200 bp bgs 1404 and 13 150 100 bp we 01 89 th

the younger dryas and late pleistocene peoples of the great lakes region abstract the late pleistocene archaeological record of the great lakes drainage area shows that there were several albeit spatially variable changes in that record in a time period corresponding to the younger dryas yd climatic reversal at ca 10 800 10 000 14 c bp notable here are declines in some areas in the mobility of paleoindian groups as measured by distance to the main lithic source employed declines in the overall frequency of sites findpots particularly in the western great lakes where some northern areas seem to have been largely abandoned and an increasing association of occupation locales with glacial lake shores or extensive wetlands left by recently drained glacial lakes some of the changes as in range mobility most likely relate to the colonization of new areas rather than directly to the yd specifically the earliest groups were able to target rich but widely dispersed resource locales due to an absence of competing groups however the declines in locale frequencies and shifting distributions of those locales may be due to yd influence notably to an eventual drying out of the area that resulted in less productive environments overall and made the lake shores and wetland areas more attractive environmental niches for human occupation

a woolly mammoth proboscidea mammuthus primigenius molar from the hudson bay lowland of manitoba the first fossil mammal from the hudson bay lowland of manitoba a molar from the woolly or siberian mammoth mammuthus primigenius is described from near bird a lophar index of 9 0 and an enamel thickness of 1 5 2 3 mm allow the tooth to be assigned to an early form of the species although in situ provenance of the molar is unknown it is likely that the molar derives from early wisconsinan or sangamon sediments that outcrop in the area a boreal steppe or steppe tundra environment is indicated by the presence of woolly mammoth supporting a depositional environment north of the then tree line previously established for the nelson river sediments

dung of mammuthus in the arid southwest north america abstract the discovery of a unique organic deposit in a dry cave on the colorado plateau southern utah permits the first comparison of the physical characteristics and the diet of the dung of the extinct mammoths from the arid southwest north america with that of mammoths from siberia and northern china the only other known locations of such remains the deposit buried beneath sand and rockfall is composed primarily of mammoth dung estimated at over 300 m3 radiocarbon dates on dung boluses indicate that the mammoths frequented the cave between approximately 14 700 and 11 000 yr b p the range of ages at 2 the desiccated boluses measuring approximately 230 170 85 mm are nearly identical in size to dung from extant elephants the largest contents in the dung are stalks measuring 60 4 5 mm grasses and sedges dominated the diet although woody species were commonly eaten

neutron activation analysis of 12 900 year old stone artifacts confirms 450 510 km clovis tool stone acquisition at paleo crossing 33me274 northeast ohio u s a the archaeologically sudden appearance of clovis artifacts 13 500 12 500 calibrated years ago across pleistocene north america documents one of the broadest and most rapid expansions of any culture known from prehistory one long asserted hallmark of the clovis culture and its rapid expansion is the long distance acquisition of exotic stone used for tool manufacture given that this behavior would be consistent with geographically widespread social contact and territorial permeability among mobile hunter gatherer populations here we present geochemical evidence acquired from neutron activation analysis naa of stone flaking debris from the paleo crossing site a 12 900 year old clovis camp in northeastern ohio these data indicate that the majority stone raw material at paleo crossing originates from the wyandotte chert source area in harrison county indiana a straight line distance of 450 510 km our analyses thus geochemically confirm an extreme stone source to camp site distance of a clovis site in eastern north america and thus provide strong inferential material evidence that the fast expansion of the clovis culture across the continent occurred as a result of a geographically widespread hunter gatherer social network

oxygen isotope analyses of co existing carbonate and phosphate in biogenic apatite a way to monitor diagenetic alteration of bone phosphate abstract the oxygen isotopic composition of phosphate 18 op and structural carbonate 18 oc of hydroxylapatite was determined in 31 bone and tooth samples of modern mammals from different countries these two variables are highly correlate r 2 0 98 and the calculated best fit of linear regression is very similar to the equation calculated from the phosphate and carbonate palaeotemperature equations 1 2 according to previous measurements 3 6 on fossils of different ages from different areas it seems quite improbable to find isotopically altered skeletal remains showing a good correlation between 18 op and 18 oc as is the case with modern samples it therefore seems possible at least in some cases to use these measurements for monitoring fossil bone and tooth diagenetic alteration when a set of points lie on the equilibrium line or close to it the 18 o values could be considered close to the original values in contrast when the points lie to the left or to the right of this line this probably means that the values are diagenetically modified due to interaction with meteoric water or 18 o enriched water respectively

oxygen isotope variation in the tusks of extinct proboscideans a measure of season of death and seasonality centimetre scale laminae in tusk and molar dentine of late pleistocene mastodonts and mammoths have been interpreted as annual growth bands produced in part by seasonal variation in growth rate to test this interpretation we measured the oxygen isotope composition 18 o of the co 3 fraction of dentinal hydroxyapatite from samples covering consecutive inferred years of growth in tusks in mammals changes in the 18 o value of dental tissues within individuals predominantly reflect variation in the 18 o value of body fluids which is controlled mainly by the isotopic composition of ingested water in northern hemisphere continental regions winter precipitation has substantially lower 18 o values than does precipitation in other seasons if ingested water tracks focal precipitation then seasonal variations in dentinal isotope composition should result the lowest 18 o values representing winter growth we demonstrate that there are substantial variations in the oxygen isotope composition of proboscidean dentinal apatite and that isotopic identifications of winter i e low 18 o values coincide with those based on growth rate i e slow growth zones finally the potential of oxygen isotope analyses of terrestrial mammals for assessing the seasonality of paleoclimates is considered

climate information from c n and o stable isotope analyses of mammoth bones from northern siberia abstract nineteen late pleistocene samples of fossil mammoth and four of horse and bison from the leptev sea area were studied for their c n and o stable isotope composition the majority of the samples have interstadial mis 3 ages and only two have late glacial ages the carbon and nitrogen isotope values are in good agreement with those previously measured on other mammoths from the same area they seem to indicate for the interstadial period a stability of the climate conditions characterised by low and constant rainfall with only few oscillations only after the lgm are more humid conditions apparent the calculated oxygen isotope composition of water are several per mill more positive than those of modern meteoric water in the area they do not seem to correlate with well established late pleistocene temperature changes but rather with aridity the temporal pattern indicates a rapid increase of dry conditions after around 34 ka bp only the two samples dated after the lgm might indicate an effective increase in temperature

environmental change and seasonal behavior of mastodons in the great lakes region inferred from stable isotope analysis abstract we investigate seasonal variations in the diet and drinking water of four great lakes mastodon mammut americanum specimens using stable isotope analysis of serially sampled inner enamel bioapatite structural carbonate 13 c sc 18 o sc and previously published bulk analyses isotopic analyses and thin section measurements showed that mastodon tooth enamel extension rates 12 4 mm yr decreasing toward the cervix were lower than those of mammoths or modern elephants mastodons had distinct and highly regular seasonal variations in 13 c sc and 18 o sc which we interpret in the context of local glacial history and vegetation changes seasonal variations in 18 o were large but variations in 13 c were small and may have been obscured if coarser sampling methods than our inner enamel sampling approach were used thus our approach may be particularly useful for understanding relatively small seasonal changes in 13 c within c 3 environments the seasonal patterns though not entirely conclusive suggest that the ontario mastodons did not migrate over very long distances rather the climate and seasonal dietary patterns of mastodons within the region changed over time from 12 400 to 10 400 14 c yr bp 15 000 12 000 cal yr bp insights gained using these methods can contribute to a better understanding of megafaunal extinctions and paleoamerican lifeways

proboscideans and paleoenvironments of the pleistocene great lakes landscape vegetation and stable isotopes abstract in this study we review the history of proboscideans in the great lakes region ontario and western new york in the context of local glacial and vegetational histories further we investigate mammoth mammuthus and mastodon mammut environmental niche partitioning using stable isotope analysis of bone and dentin collagen 13 c col 15 n col and structural carbonate in tooth enamel bioapatite 13 c sc 18 o sc and demonstrate that stable isotopes can be used to identify non locals among museum specimens with no contextual records new radiocarbon dates suggest that ontario mastodons lived in tundra like environments as well as their more common spruce forest habitat local ontario new york mammoths and mastodons consumed 100 c 3 plant diets and drank low 18 o waters consistent with colder than modern climates and proximity to glacial meltwater sources mammoths and mastodons occupied distinct environmental niches characterized by different oxygen and nitrogen isotope compositions and geographical locations this suggests that direct competition for resources was not a major factor in their local extinction we suggest that both mammoths and mastodons obtained water from sources formed primarily from precipitation rather than glacial meltwater we describe how high 15 n values in mammoths could have been caused by a combination of preferences for dry environments consumption of low nutrient forage particularly stems and stalks coprophagy geophagy and dung fertilization we argue that low 15 n values in mastodons could have been caused by consumption of trees and shrubs including nitrogen fixing taxa and a preference for recently deglaciated landscapes and or spruce environments finally we raise the possibility that mastodons contributed to the spruce pine transition by browsing directly on spruce trees

can carbon 13 in large herbivores reflect the canopy effect in temperate and boreal ecosystems evidence from modern and ancient ungulates abstract local environmental conditions under dense canopy are known to result in depletion in 13c abundance in plants compared to an open land context this canopy effect has been observed in tropical as well as in mid latitude forest ecosystems however the impact of the canopy effect on tissue 13c abundance of temperate and boreal forest dwelling herbivores has not been thoroughly explored nevertheless the canopy effect has been suggested to explain a decrease of about 3 in collagen 13c values in ancient large herbivores from western europe during the forest expansion of the late glacial early holocene period ca 15 000 6000 cal bp some papers have considered the 13c decrease in large herbivore as the main result of global change in atmospheric co2 content a detailed review of 13c values of large herbivores reindeer red deer roe deer and bison from open and closed environments from high and mid latitudes confirm that the canopy effect observed in plants is passed on to their consumers in the paris basin the decline in 13c values of large herbivores at the late glacial early holocene transition around 10 000 years bp appears to be different according to the considered species namely red deer roe deer and large bovines bison and aurochs moreover differences in the pattern of decrease in 13c values are observed in red deer between french northern alps and french jura these differences among species in their isotopic response through time for a given geographical location and within species from different locations suggest variance in ecological responses of species that are associated with the relative use of forested habitat as a result 13c abundances in collagen can be considered as a direct tracker of the degree of closure of the habitat of ancient herbivores

preparation and characterization of bone and tooth collagen for isotopic analysis abstract criteria are presented for the identification of diagenetic alteration of carbon and nitrogen isotope ratios of bone and tooth collagen prepared by a widely used method measurements of collagen concentrations in tooth and bone atomic c n ratios and carbon and nitrogen concentrations in collagen of 359 historic and prehistoric african humans and modern and prehistoric east african non human mammals are described carbon isotope ratios of collagen lipids from four bones are also presented compared to bone whole teeth have significantly lower collagen concentrations lower carbon and nitrogen concentrations in collagen and similar c n ratios carbon and nitrogen concentrations and c n ratios are relatively constant over a wide range of collagen concentrations however prehistoric specimens with very low collagen concentrations have highly variable c n ratios very low carbon and nitrogen concentrations in collagen and stable carbon and nitrogen isotope ratios unlike collagen at the transition from well preserved to poorly preserved collagen the most reliable indicator of collagen preservation is the concentration of carbon and nitrogen in collagen concentrations of c and n drop abruptly by an order of magnitude at this transition point these attributes provide simple criteria for assessing sample quality since collagen preservation can vary greatly within prehistoric sites these attributes should be reported for each specimen use of purification procedures that remove acid and base soluble contaminants and particulate matter carbonates fulvic acids lipids humic acids sediments and rootlets are recommended wider adoption of these procedures would insure comparability of results between laboratories and permit independent and objective evaluation of sample preservation and more precise dietary climatic and habitat interpretations of collagen isotopic analyses

preservation assessment of miocene pliocene tooth enamel from tugen hills kenyan rift valley through ftir chemical and stable isotope analyses abstract we investigated fossil tooth enamel of mammals and crocodiles from two mio pliocene east african formations lukeino and mabaget fms using infrared spectroscopy and chemical and stable isotope analyses infrared spectra indicate that the fossil enamel contains biological apatite bioapatite without significant secondary carbonate contaminations several empirical infrared indexes were used to analyze the crystal chemical characteristics of enamel fossil enamel has less organic matter water and structural carbonate of apatite than modern enamel with which it was compared fossil apatite has a better crystallinity than bioapatite the calcium phosphorus mass ratio and the fluorine content of fossil apatite show intermediate values between bioapatite and geological fluorapatite the samples also display significant crystal chemical variations depending on the vertebrate group mammals vs reptiles and the taphonomic context lukeino fm vs mabaget fm in spite of these changes no relationship was observed between the chemical contents carbonate and fluorine and the stable isotope ratios of carbonate 13 c and 18 o in fossil enamel preservation of the palaeoenvironmental signals is strongly supported by the fact that the stable isotope composition of the three investigated fossil mammalian taxa deinotheres equids and hippos is consistent with their ecological features for instance typical c 3 and c 4 plant isotope compositions are reflected in the deinotheres and equids respectively and amphibious hippos display lower 18 o values than terrestrial herbivores as expected

lakes of the huron basin their record of runoff from the laurentide ice sheet the 189 000 km2 hur n basin is central in the catchment area f the present q s r lanrentian great lakes that now drain via the st lawrence river to the north atlantic ocean during deglaciation from 21 7 5 ka bp and owing to the interactions of ice margin positions crustal rebound and regional topography this basin was much more widely connected hydrologi cally draining by various routes to the gulf of mexico and atlantic ocean and receiving over flows from lakes impounded north and west of the great lakes hudson bay drainage divide early ice marginal lakes formed by impoundment between the laurentide ice sheet and the southern margin of the basin during recessions to interstadial positions at 15 5 and 13 2 ka be in i each of these recessions lake drainage was initially southward to the mississippi river and gulf of mexico in the first recession drainage subsequently switched eastward along the ice margin to the north atlantic ocean in the second recession drainage continued southward through the michigan basin and later eastward via the ontario basin and mohawk river valley to the north atlantic ocean during the final retreat of ice in the huron basin from 13 to 10 ka be proglacial lake drainage switched twice from the michigan basin and the mississippi river system to the i north atlantic via the ontario basin and mohawk river valley finally diverting to the champlain sea in the st lawrence river valley at about 11 6 ka be new seismo and litbo stratigraphic information with ostracode data from the offshore lacustrine sediments were integrated with the traditional data of shorelines uplift histories of outlets and radio carbon dated shallow water evidence of transgressions and regressions to reconstruct the water level history and paleolimnological record for the northern huron basin for the 11 7 ka bp period negative excursions in the 8 80 isotopic composition of ostracodes and bivalves in southern lake michigan southwestern lake huron and eastern lake erie indicate an influx of water from ice marginal lake agassiz in central north america about 11 ka be a major decline in water levels of the huron basin after 10 5 ka bp followed the high level main lake algonquin phase as ice receded and drainage was established through the north bay area to ottawa river valley during the subsequent mattawa stanley phase the lake level history was dominated by fluctuations of tens of meters highstands of the earliest oscillations whose origin is not clear might be related to some of the well known post algonquin shorelines after 9 6 ka be it is suggested that large inflows from lake agassiz and hydraulic damming in downstream outlets were the likely cause of the lake mattawa highstands a lowstand at 9 3 9 1 ka bp occurred when these inflows were diverted or impeded by an ice advance in the nipigon basin area while undiluted meltwater continued to enter the huron basin assemblages and isotopic composition of the ostracode fauna indicate very dilute meltwater during the lowstands as late as 7 5 ka be and precipitation runoff with comparatively higher dissolved solids dur ing the highstands we speculate that the water composition of the lake mattawa highstands was dom inated by the agassiz inflows by that time much of lake agassiz was remote from ice marginal envi ronments and the inflows were drawn from surface water of the southern sector of the lake which was largely supplied by runoff and dissolved solids from the exposed land area of western canada major inflows apparently ended about 8 ka be but northern proglacial lakes apparently continued as melt water persisted in the huron basin until about 7 5 ka bp the cessation of major inflows initiated the final lowstand in the huron basin and the present hydrological regime of local runoff

patterns and implications of plant soil δ13c and δ15n values in african savanna ecosystems abstract southern african savannas are mixed plant communities where c3 trees co exist with c4 grasses here foliar 15n and 13c were used as indicators of nitrogen uptake and of water use efficiency to investigate the effect of the rainfall regime on the use of nitrogen and water by herbaceous and woody plants in both dry and wet seasons foliar 15n increased as aridity rose for both c3 and c4 plants for both seasons although the magnitude of the increase was different for c3 and c4 plants and for two seasons soil 15n also significantly increased with aridity foliar 13c increased with aridity for c3 plants in the wet season but not in the dry season whereas in c4 plants the relationship was more complex and non linear the consistently higher foliar 15n for c3 plants suggests that c4 plants may be a superior competitor for nitrogen the different foliar 13c relationships with rainfall may indicate that the c3 plants have an advantage when competing for water resources the differences in water and nitrogen use likely collectively contribute to the tree grass coexistence in savannas such differences facilitate interpretations of palaeo vegetation composition variations and help predictions of vegetation composition changes under future climatic scenarios

isotopic paleoecology of clovis mammoths from arizona the causes of megafaunal extinctions in north america have been widely debated but remain poorly understood mammoths mammuthus spp in the american southwest were hunted by clovis people during a period of rapid climate change just before the regional onset of younger dryas cooling and mammoth extirpation thus these mammoths may provide key insights into late pleistocene extinction processes here we reconstruct the seasonal diet and climatic conditions experienced by mammoths in the san pedro valley of arizona using the carbon 13c 12c and oxygen 18o 16o isotope compositions of tooth enamel these records suggest that clovis mammoths experienced a warm dry climate with sufficient summer rainfall to support seasonal c4 plant growth monsoon intensity may have been reduced relative to the preceding time period but there is no isotopic evidence for severe drought however it is possible that the clovis drought inferred from stratigraphic evidence occurred suddenly at the end of the animals lives and thus was not recorded in the enamel isotopic compositions unlike mammoths that lived before the last glacial maximum clovis mammoths regularly increased c4 grass consumption during summer probably seeking seasonally green grasslands farther from the river valley this predictable seasonal behavior may have made mammoths easier to locate by clovis hunters furthermore clovis mammoths probably had no previous experience of such sudden climatic change as is believed to have occurred at the time of their extinction

post clovis survival of american mastodon in the southern great lakes region of north america abstract the end of the pleistocene in north america was marked by a wave of extinctions of large mammals with the last known appearances of many species falling between ca 11 000 10 000 14c yr bp temporally this period overlaps with the clovis paleoindian cultural complex 11 190 10 530 14c yr bp and with sudden climatic changes that define the beginning of the younger dryas chronozone ca 11 000 10 000 14c yr bp both of which have been considered as potential proximal causes of this extinction event radiocarbon dating of enamel and filtered bone collagen from an extinct american mastodon mammut americanum from northern indiana usa by accelerator mass spectrometer yielded direct dates of 10 055 40 14c yr bp and 10 032 40 14c yr bp indicating that the animal survived beyond the clovis time period and into the late younger dryas although the late survival of this species in mid continental north america does not remove either humans or climatic change as contributing causes for the late pleistocene extinctions neither clovis hunters nor the climatic perturbations initiating the younger dryas chronozone were immediately responsible for driving mastodons to extinction

rancho la brea stable isotope biogeochemistry and its implications for the palaeoecology of late pleistocene coastal southern california abstract we sampled 143 individuals from rancho la brea rlb large faunal collections for bone collagen stable carbon 13c and nitrogen 15n isotope ratios these collections were recovered from asphalt seeps in the los angeles basin california usa and date from 40 to 12 ka our findings indicate that despite a slight reduction in collagen nitrogen content rlb skeletal remains are relatively well preserved and most yield proteins diagnostic of diet herbivore 13c and 15n values covary with rumination and are consistent with changes in late pleistocene vegetation reconstructed from pollen profiles we find no evidence for reliance on c4 grasses at rlb despite low atmospheric co2 concentrations carnivore 15n values indicate canis dirus smilodon fatalis and panthera leo atrox competed for similar prey sets and were equally reliant on ruminant and nonruminant prey types the 15n values of mammut americanum indicate partial reliance on vegetation with lower 15n values such as nitrogen fixing taxa distinguishing them from the remainder of the study population a comparison of rlb and european faunal 15n values from the late pleistocene suggests that coastal southern california experienced greater aridity

great lakes paleohydrology complex interplay of glacial meltwater lake levels and sill depths the oxygen isotope record of ostracode and clam shells recovered from great lakes cores of known age allows definition of times when meltwaters from the laurentide ice sheet were important components of lake water in the several lake basins since 12 ka we find that the lowstands in lake huron and georgian bay are characterized by isotopically light waters 18 o values of 20 to 22 relative to smow standard mean ocean water and the highstands by isotopically heavy waters of more local origin these data can be used to determine the degree of hydraulic separation among the early holocene lakes southern lake michigan for instance may mix with northern source waters only during times of rising and high water levels generally it is characterized by waters of local origin

mastodon herbivory in mid latitude late pleistocene boreal forests of eastern north america skeletal remains of the extinct american mastodon have often been found with deposits of short decorticated twigs intermixed with plant fragments presumed to be gastrointestinal or fecal material if such deposits are digesta paleobotanical evidence may be used to analyze mastodon foraging strategy with implications for assessing habitat selection ecological roles and response to environmental change to identify components of mastodon diet in mid latitude late pleistocene boreall forests of eastern north america plant macrofossils and pollen from a molar socket hyde park site new york were compared with dispersed deposits associated with skeletal remains hiscock and chemung sites new york similar macrofossil condition and twig morphology among samples but difference from a modern boreal fen analog confirmed the deposits were digesta comparison of twigs with material from other paleontological sites and modern elephants suggested dimensions generally indicative of digesta picea formed the bulk of each sample but pinus may have been locally important wintertime browsing of salix and populus and springtime consumption of alnus were indicated evidence for cyperaceae gramineae and compositae was ambiguous if conifers broadleaf trees shrubs and herbs were necessary to fulfill dietary requirements mastodons would have been nutritionally stressed by rapid late pleistocene decrease in vegetational diversity

quaternary chronostratigraphy and stable isotope paleoecology of big bone lick kentucky usa abstract big bone lick bbl in northern kentucky usa has been a critical geologic site in the historical development of north american quaternary vertebrate paleontology since the 1700s sedimentology geoarcheology paleontology accelerator mass spectrometry radiocarbon and optically stimulated luminescence dating and stable carbon and nitrogen isotope analyses were undertaken to develop a chronostratigraphy and history of erosion and deposition for the site to provide a foundation for understanding taphonomy and species extinction and adaptation to periods of climatic and environmental change three geomorphic surfaces are recognized at bbl representing significant periods of floodplain aggradation since the last glacial maximum 26 5 19 ka dating to the oldest dryas tazewell 25 19 ka the older dryas cary 14 12 ka and late holocene 5 ka to the present unconformities suggest significant periods of degradation during the transitions from cold and dry to warm and moist climates from the oldest dryas tazewell to bolling oscillation from the older dryas cary to the allerod and from the younger dryas valders to the holocene climatic optimum increased anthropogenic activities since 5 ka may have increased soil upland erosion and floodplain aggradation stable isotopes demonstrate that the landscape has been dominated by c3 vegetation since the last glacial maximum

regional differences in bone collagen δ13c and δ15n of pleistocene mammoths implications for paleoecology of the mammoth steppe in this study we present bone collagen 13c and 15n values from a large set of pleistocene woolly mammoths mammuthus primigenius from siberia alaska and yukon overall results for mammoth specimens from eastern beringia alaska and yukon significantly differ for both 13c and 15n values from those from western beringia northeastern siberia in agreement with palynological entomological and physiographic data from the same regions these isotopic differences strongly imply that the mammoth steppe the extensive ice free region spanning northern eurasia and northwestern north america was ecologically variable along its east west axis to a significant degree prior to the last glacial maximum lgm the high latitude portions of siberia and the russian far east appear to have been colder and more arid than central alaska and yukon which were ecologically more diverse during the lgm itself however isotopic signatures of mammoths from eastern beringia support the argument that this region also experienced an extremely cold and arid climate in terms of overall temporal trend beringia thus went from a condition prior to the lgm of greater ecological variability in the east to one of uniformly cold and dry conditions during the lgm

unravelling fluvial deposition and pedogenesis in ephemeral stream deposits in the vicinity of the prehistoric rock shelter of ifri n ammar ne morocco during the last 100 ka abstract our study focuses on the ephemeral stream deposits of wadi selloum to identify phases of morphodynamic stability pedogenesis and activity flooding in the direct vicinity of the rock shelter of ifri n ammar ne morocco as one of the oldest settlement sites of anatomically modern humans amh in north africa ifri n ammar documents periodical occupations since 170 ka since the discontinuous settlement record may reflect climate forcing with subsequent landscape changes we aim at reconstructing the palaeoenvironmental variability recorded in the ephemeral stream deposits in addition to the use of micromorphological sedimentological geochemical and mineralogical methods the geochronological framework of ephemeral stream deposits was established by the application of different luminescence dating techniques the deposition ages between 102 8 ka and 1 3 0 2 ka span different morphodynamically stable and active phases periods of enhanced aggradation occurred around 100 ka 75 ka 55 ka after the lgm and during the holocene whilst sedimentation ended after 1 3 ka the wadi selloum might be characterised by enhanced flooding during humid phases pedogenesis may be used as environmental indicator for more humid climate conditions during mis 3 palaeo calcisol the early holocene calcisol and the late holocene fluvisol this study thus provides first insights into the palaeoenvironmental changes around the rock shelter of ifri n ammar during the last glacial interglacial cycle

younger dryas black mats and the rancholabrean termination in north america of the 97 geoarchaeological sites of this study that bridge the pleistocene holocene transition last deglaciation approximately two thirds have a black organic rich layer or black mat in the form of mollic paleosols aquolls diatomites or algal mats with radiocarbon ages suggesting they are stratigraphic manifestations of the younger dryas cooling episode 10 900 b p to 9 800 b p radiocarbon years this layer or mat covers the clovis age landscape or surface on which the last remnants of the terminal pleistocene megafauna are recorded stratigraphically and chronologically the extinction appears to have been catastrophic seemingly too sudden and extensive for either human predation or climate change to have been the primary cause this sudden rancholabrean termination at 10 900 50 b p appears to have coincided with the sudden climatic switch from allerod warming to younger dryas cooling recent evidence for extraterrestrial impact although not yet compelling needs further testing because a remarkable major perturbation occurred at 10 900 b p that needs to be explained

flute like marks and associated structures from the carboniferous port hood formation of eastern canada evidence of secondary origin in association with sediment intrusion abstract flutes have been described and interpreted for many years as sole marks preserved in positive relief on the bases of sandstone beds and formed on underlying firm mud substrates mainly by corrasion at the sediment water interface by fluvial tidal or turbidity currents structures resembling flutes herein termed flute like marks or flms from fluvial sandstone of the port hood formation mid carboniferous of western cape breton island are present not only on the undersides but also on the vertical inclined stepped and top surfaces of sandstone beds in contact with mudstone bodies these occurrences are difficult to reconcile with primary sedimentary processes even allowing for complex and fortuitous preservation e g by erosion of slumped mudstone bodies or as scoured and verturned mudstone boulders the presence of associated soft sediment deformation structures such as convolute bedding mudstone diapirs and mud injection structures some of which also have flute like marks on their surfaces suggests that these structures are explained more readily by sediment intrusion rheoplasis than by current scour and infill since flute like marks have been recognized as positive relief structures on both upper and inclined mudstone sandstone interfaces in modern tidal flat environments and on experimental injection structures we reemphasize that they should not be regarded as excellent criteria for indicating way up and paleocurrent direction

nursing weaning and tooth development in woolly mammoths from old crow yukon canada implications for pleistocene extinctions abstract this study investigates differences in the 13ccol 15n 13csc 18osc sr ca and ba ca values of juvenile and adult woolly mammoths mammuthus primigenius from old crow yukon canada the data indicate that nursing in woolly mammoths lasted at least three years and was associated with minimal decreases in 13ccol 0 2 large decreases in 13csc 1 5 and large increases in 15n 2 and 18osc 2 values sr ca and ba ca ratios suggest that woolly mammoth juveniles began consuming plant foods between 2 and 3 african elephant years of age much later than the initiation of weaning in modern elephants we hypothesize that delayed weaning was an adaptation to increased predation risk and decreased food quality quantity during the extended hours of darkness that occur in winter at high latitudes prolonged nursing and delayed weaning may have made mammoths particularly vulnerable to climatic stressors or human hunting

evidence for general instability of past climate from a 250 kyr ice core record recent results1 2 from two ice cores drilled in central greenland have revealed large abrupt climate changes of at least regional extent during the late stages of the last glaciation suggesting that climate in the north atlantic region is able to reorganize itself rapidly perhaps even within a few decades here we present a detailed stable isotope record for the full length of the greenland ice core project summit ice core extending over the past 250 kyr according to a calculated timescale we find that climate instability was not confined to the last glaciation but appears also to have been marked during the last interglacial as explored more fully in a companion paper3 and during the previous saale holstein glacial cycle this is in contrast with the extreme stability of the holocene suggesting that recent climate stability may be the exception rather than the rule the last interglacial seems to have lasted longer than is implied by the deep sea specmap record4 in agreement with other land based observations5 6 we suggest that climate instability in the early part of the last interglacial may have delayed the melting of the saalean ice sheets in america and eurasia perhaps accounting for this discrepancy

c and n stable isotope measurements on eurasian fossil mammals 40 000 to 10 000 years bp herbivore physiologies and palaeoenvironmental reconstruction abstract seventy seven specimens of fossil upper pleistocene early holocene woolly mammoth reindeer deer and bison from 17 different locations in eurasia have been measured for the nitrogen and carbon stable isotope composition of their collagen and for the carbon stable isotope composition of bioapatite the aim was 1 to check the existence of differences in n and c isotope ratios between and within different herbivore species mainly between mammoth and reindeer 2 to discuss these data in terms of animal physiology temporal and spatial distribution of animals and effects of climatic changes and 3 to obtain further information about the environmental changes that occurred in that area during the period considered a geographical variation from south west to north east in the 15n and or 13c values of collagen and bioapatite for all the herbivore species is apparent the most negative 13c values and the most positive 15n values being located in the north eastern area this was probably due to a different temperature and water stress on animals and plants and to a different plant availability the differences in 13c 12c and 15n 14n isotope ratios among species are mainly related to different food intake and different metabolic pathways it seems also that the diet of mammoths from north eastern siberia was higher in protein content compared with that of mammoths from the russian plain from this study it is clear that there was a rapid and important change in the amount of precipitation soon after the last glacial maximum the rainfall conditions around 40 000 and 30 000 years bp were probably similar to those existing around 10 000 years bp though lower than those existing after the glacial maximum

the reconstruction of mammal individual history refining high resolution isotope record in bovine tooth dentine abstract longitudinal and transverse carbon isotope profiles were performed on tooth dentine from five steers bos taurus initially fed c3 and subsequently c4 dominant food comparison of different protocols for bioapatite extraction revealed that the use of naocl considerably reduced the amplitude of variation of 13c within a tooth increasing contribution of c4 food to the carbon isotope composition of bioapatite was found from the tip of the tooth crown to the neck and from the enamel dentine junction toward the pulp cavity these findings confirm that the model of dentine growth as a succession of stacked cones applies to bovines temporal resolution is estimated to be 4 months in transverse profiles significantly better than in longitudinal dentine profiles 8 9 months or even in profiles derived from enamel of the same individual 6 7 months temporal resolution could be improved by a factor of two by selecting a different sampling zone or refining our sampling protocol this sampling strategy could also be applied to dentine collagen and has important ecological and archaeological implications including determination of the season of weaning or the reconstruction of mobility strategies

the preservation of glacial interglacial climatic signatures in the oxygen isotopes of elephant skeletal phosphate abstract phosphate 18o values 18op of modern elephant bone and teeth are found to vary linearly according to the 18o of local meteoric water 18omw a parameter with close ties to regional and local climatic conditions enamel dentine cementum and bone separates from individual fossil elephant specimens of late pleistocene age have op values which vary by up to elephant specimens the larger spread in the 18op values of the various skeletal phases for the fossil samples is interpreted as evidence for post depositional alterantion of primary 18op signatures of some if not all of these fossil skeletal components in the fossil samples investigated enamel and dentine phases have systematically lower 18o values than associated bone and cementum phases differential re equilibration with soil waters either by the wholesale replacement of primary apatite or by processes of isotopic exchange is suggested as a mechanism to account for the observed spread in the fossil phosphate 18o data

the hillsborough new brunswick mastodon and comments on other pleistocene mastodon fossils from nova scotia this is the first detailed description of the remains of a young adult american mastodon mammut americanum found in 1936 in peaty silt and clay underlying till in gypsum karst near hillsborough new brunswick it documents 312 fossils comprising a partial skull with molar teeth and tusks a neck vertebra and much of the right postcranial skeleton an individual age of 15 18 years and a weight of 8 3 t are estimated for this mastodon associated spheroids containing cut wood fragments and an unusually high clay content are interpreted to be mastodon coprolites radiocarbon ages are 13 600 200 bone 37 200 1 310 coprolite wood 51 500 1 270 coprolite carbonate cement and 43 000 bp peat pollen in the coprolites and associated sediment indicates a coniferous forest nine other mastodon fossils from nova scotia include a femur from middle river which dates 31 300 500 bp and contains pollen representing boreal forest tundra and three molars from offshore georges bank all ages are

the effects of dental wear on impairing mammoth taxonomy a reappraisal of the newton mammoth bradford county northeastern pennsylvania a mammoth skeleton found at the newton site a kettle lake 15 km southeast of towanda pennsylvania has been referred to mammuthus columbi on the basis of its high narrow skull however the specimen s thin enamel 1 3 1 8 mm and moderately high lamellar frequency 8 8 75 lophs dm resemble some specimens of mammuthus primigenius prehistoric range maps show that a columbian mammoth inhabiting the towanda area would be a significant outlier from this species range however its location would align well with the range of m primigenius to better ascertain the newton mammoth s identification we examine herein the effects of dental wear on the morphology of mammoth molars as mammoth molars wear the enamel lophs become more broadly spaced and the enamel ridges thicken towards the base of the crown thus an older m primigenius with extensively worn molars might display thicker enamel and a lower lamellar frequency and might therefore appear to be a columbian mammoth on the basis of dental morphology alone our results show that the molars of the newton mammoth are well worn and are characterized by an enamel thickness and lamellar frequency that aligns better with m primigenius than with m columbi we conclude that one must take into account the effects of dental wear when classifying mammoth species using solely molars

stable isotope o and c and pollen trends in eastern lake erie evidence for a locally induced climatic reversal of younger dryas age in the great lakes basin a cool period from about 11000 to 10 500 bp 11 to 10 5 ka is recognized in pollen records from the southern great lakes area by the return of picea and abies dominance and by the persistence of herbs the area of cooling appears centred on the upper great lakes a high resolution record ca 9 mm y from a borehole in eastern lake erie reveals in the same time interval this pollen anomaly isotope evidence of meltwater presence a 3 per mil shift in 18o and a 1 1 per mil shift in 13c increased sand and reduced detrital calcite content all suggesting concurrent cooling of lake erie the onset of cooling is mainly attributed to the effect of enhanced meltwater inflow on the relatively large upstream main lake algonquin during the first eastward discharge of glacial lake agassiz termination of the cooling coincides with drainage of lake algonquin and is attributed to loss of its cooling effectiveness associated with a substantial reduction in its surface area it is hypothesized that the cold extra inflow effectively prolonged the seasonal presence of lake ice and the period of spring overturn in lake algonquin the deep mixing would have greatly increased the thermal conductive capacity of this extensive lake causing suppression of summer surface lakewater temperatures and reduction of onshore growing degree days alternatively a rapid flow of meltwater buoyed on sediment charged denser lakewater may have kept the lake surface cold in summer other factors such as wind shifted pollen deposition and possible effects from the younger dryas north atlantic cooling could have contributed to the great lakes climatic reversal but further studies are needed to resolve their relative significance

american mastodon extirpation in the arctic and subarctic predates human colonization and terminal pleistocene climate change existing radiocarbon 14c dates on american mastodon mammut americanum fossils from eastern beringia alaska and yukon have been interpreted as evidence they inhabited the arctic and subarctic during pleistocene full glacial times 18 000 14c years b p however this chronology is inconsistent with inferred habitat preferences of mastodons and correlative paleoecological evidence to establish a last appearance date lad for m americanum regionally we obtained 53 new 14c dates on 36 fossils including specimens with previously published dates using collagen ultrafiltration and single amino acid hydroxyproline methods these specimens consistently date to beyond or near the 50 000 y b p limit of 14c dating some erroneously young 14c dates are due to contamination by exogenous carbon from natural sources and conservation treatments used in museums we suggest mastodons inhabited the high latitudes only during warm intervals particularly the last interglacial marine isotope stage mis 5 when boreal forests existed regionally our 14c dataset suggests that mastodons were extirpated from eastern beringia during the mis 4 glacial interval 75 000 y ago following the ecological shift from boreal forest to steppe tundra mastodons thereafter became restricted to areas south of the continental ice sheets where they suffered complete extinction 10 000 14c years b p mastodons were already absent from eastern beringia several tens of millennia before the first humans crossed the bering isthmus or the onset of climate changes during the terminal pleistocene local extirpations of mastodons and other megafaunal populations in eastern beringia were asynchrononous and independent of their final extinction south of the continental ice sheets

ecosystem response to lateglacial and early holocene climate oscillations in the great lakes region of north america abstract fossil pollen plant macrofossils gastropods and elemental and stable isotope geochemistry in a sediment core from twiss marl pond southern ontario canada were used to document climate oscillations during the last glacial interglacial transition 13 000 8500 14 c bp and understand their ecological effects chronology was provided by ams 14 c dating and regional pollen correlation oxygen isotope 18 o results from mollusc shells chara encrustations and bulk carbonates show a classic climate sequence of a warm bolling allerod boa at 12 500 10 920 14 c bp a cold younger dryas yd at 10 920 10 000 14 c bp the holocene warming at 10 000 14 c bp a brief preboreal oscillation pb at 9650 14 c bp and a possible gerzensee killarney g k cooling shortly before 11 000 14 c bp clay sediments at the base of the core contain high herb and shrub pollen and abundant arctic alpine plant macrofossils indicating a treeless tundra with severe soil erosion in watershed during the boa warm period authigenic marl began to be deposited and picea woodland became established the establishment of picea woodland after peaks of 18 o and of carbonate accumulation suggests a lagged response of upland vegetation to boa warming in contrast the occurrence of warmth loving aquatics najas flexilis and typha latifolia at that time indicates sensitive responses of aquatic plants the yd cooling is indicated by a 1 5 negative excursion in 18 o an increase in minerogenic matter and higher concentrations of erosion derived elements al na k ti and v pollen data show no forest transformation in response to yd cooling which is attributed to the insensitive nonecotonal vegetation at that time however more openings in the forests and increased erosion in the watershed are indicated by a slight increase of herb pollen high concentrations of erosion elements and a pediastrum peak the onset of the holocene was marked by an abrupt increase of 2 in 18 o and the replacement of picea woodland by pinus dominated forest the picea recurrence at 9650 14 c bp demonstrates sensitive response of ecotonal vegetation to the pb climate oscillation which is also indicated by 0 4 negative excursion of 18 o these new results suggest the importance of multiproxy records for reliable paleoclimate reconstruction reevaluation and revised chronologies of previously published sites gage street and nichols brook in the eastern great lakes region show their major 18 o shifts correlative to the yd and pb oscillations as documented from twiss marl pond and nearby crawford lake the sequence and magnitude of climatic oscillations from these sites match in detail with records from the atlantic seaboard suggesting that these oscillations are an expression of broad scale probably global climate change rather than local meltwater induced climate cooling