controls on the distribution of calcareous foraminifera in the lower carboniferous of ireland abstract microfacies analyses of thin sections from over 650 samples of asbian and brigantian late visean platform carbonates from ireland shows that foraminiferal assemblages are controlled by the relative abundance of echinoderms mainly crinoids bryozoans and calcareous algae koninckopora ungdarella and palaeoberesellids archaediscidae valvulinella and tetrataxidae thrived in algal poor crinoid and bryozoan thickets at or below fair weather wavebase late visean algal limestones contain abundant endothyridae and palaeotextulariidae and are interpreted to have been deposited at depths between 5 and 10 m the morphology of the foraminifera studied is related closely to their facies distribution many taxa inhabited high energy shallow marine algal meadow facies these include bibradya cribrospira nevillella and bradyina with cribrate apertures and other specialised test features that protected the protoplasm from damage gigasbia omphalotis globoendothyra and pseudoendothyra with large rotund or keeled multilayered tests and forschiidae with large thick walled tests infaunal taxa such as the lituotubella nevillella gigasbia and the palaeotextulariids are recorded from algal facies and appear to have been unable to survive on bryozoan and crinoidal substrates pseudoammodiscus and earlandia characterized by simple morphologies and single layered walls and endothyranopsis endothyra and eostaffella planispirally coiled with multilayered micritic tests are regarded as the least facies controlled of the taxa studied the encrusting nature of pseudolituotuba and scalebrina ensured survival in a wide range of platformal palaeoenvironments though algal meadows were not generally suitable substrates for the pseudolituotubidae the secondary deposits in the umbilical region of the asteroarchaediscinae may have been an adaptation for survival in the dense crinoidal bryozoan thickets where they lived delicate planoarchaediscus occurs in algal poor wackestone to packstone facies typical of low energy palaeoenvironments possibly at depths below 20 m howchinia which occurs with fasciella a probable alga in intraclastic wackestone facies may also have lived in water deeper than 20 m major changes in foraminiferal assemblages through the asbian and brigantian stages of the late visean are attributed to changes in associated biotic constituents early asbian endothyrid and forschiid dominated assemblages were controlled by the relative abundance of bryozoans koninckopora and palaeoberesellids by the late asbian the foraminiferal assemblages were controlled by the presence or absence of palaeoberesellids ungdarella and to a lesser extent bryozoans asbian assemblages were similar although foraminifers such as bradyinids cribrospira and globoendothyra became abundant in the late asbian a switch to predominantly echinoderm mainly crinoid and bryozoan substrates in the brigantian may have caused the major change from late asbian endothyrid and palaeotextulariid assemblages to archaediscid and tetrataxid dominated assemblages

integration of ice core marine and terrestrial records for the australian last glacial maximum and termination a contribution from the oz intimate group the degree to which southern hemisphere climatic changes during the end of the last glacial period and early holocene 30 8 ka were influenced or initiated by events occurring in the high latitudes of the northern hemisphere is a complex issue there is conflicting evidence for the degree of hemispheric teleconnection and an unresolved debate as to the principle forcing mechanism s the available hypotheses are difficult to test robustly however because the few detailed palaeoclimatic records in the southern hemisphere are widely dispersed and lack duplication here we present climatic and environmental reconstructions from across australia a key region of the southern hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change we identify a general scheme of events for the end of the last glacial period and early holocene but a detailed reconstruction proved problematic significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period copyright c 2006 john wiley sons ltd

late pleistocene glaciation of the kosciuszko massif snowy mountains australia abstract late pleistocene glaciation of the australian mainland was restricted to a small area of the southeastern highlands geomorphic mapping of the area and exposure dating using the in situ produced cosmogenic isotope 10be provides evidence for at least two distinct glaciations the early kosciuszko glaciation consisted of a single glacier advance before 59 300 5400 years ago snowy river advance the late kosciuszko glaciation comprised three glacier advances 32 000 2500 headley tarn advance 19 100 1600 blue lake advance and 16 800 1400 years ago mt twynam advance the early kosciuszko glaciation was the most extensive and the late kosciuszko advances were progressively less extensive these periods of glaciation in the highlands correspond to episodes of periglacial activity and peaks in lake levels and river discharge at lower elevations in southeastern australia glacier advances on the kosciuszko massif correlate with advances in tasmania south america and new zealand and are broadly representative of hemispheric climate changes during the last glacial cycle

a planktic foraminiferal transfer function for the southern south atlantic ocean abstract quantitative analysis of planktic foraminiferal assemblages in 81 surface sediment samples from 20 s subtropical gyre to 55 s antarctic zone in the south atlantic ocean documents a close relationship between species distribution and austral summer surface water temperature a data set including the abundance pattern of 25 taxa and morphotypes was used to establish a transfer function based on the definition of five factors altogether these factors account for 97 of the total variance of the original data and their geographic distribution is closely linked to sea surface temperatures the transfer function f81 25 5 allows reconstruction of late quaternary summer surface water temperatures in the boundary region between the antarctic cold and subtropical warm water realm 0 5 to 26 0 c the statistical error for modern data is 1 3 c

late pliocene and quaternary glaciations of new zealand abstract evidence of late pliocene glaciations is fragmentary the ross glaciation in northwest south island is correlated with the first marine faunal evidence of marked cooling in the wanganui basin in southern north island it is inferred to be in the 2 6 2 4 ma age range the porika glaciation in a separate area of northwest south island is younger judged by palynology and is correlated with a cooling 2 2 2 1 ma bp inferred from stratigraphic evidence of lowered sea level in the wanganui basin a gap of 1 5 ma in the record of glaciations is largely filled by wanganui basin marine sediments although an unconformity cuts out the record between ca 1 45 and 1 0 ma bp since then the many sedimentary cycles caused by sea level changes are presumed to be glacio eustatic in origin uplifted interglacial marine terraces back to marine oxygen isotope stage 17 and river terraces formed by cold climate aggradation are linked into the cyclic sequence through loess and tephra in their cover beds east of the south island cores from the dsdp site 594 in the southwest pacific record the earliest glaciation and higher in the core nine periods of south island glaciation in the last 0 7 ma onshore because of uplift and erosion only the last four glaciations assigned to oxygen isotope stages 10 8 6 and 4 2 are identified being named nemona waimaunga waimea and otira glaciations they are best known in north westland northwest south island where the relations of glacial outwash and interglacial shoreline deposits are displayed the late otira glaciation stage 2 is radiocarbon dated as beginning somewhat before 22 3 ka bp culminating ca 18 ka bp and ending at ca 14 ka bp when rapid deglaciation began a relatively small advance at ca 12 ka bp may have been followed by little change until after 8 6 ka bp recession was then followed by a period of advance from ca 5 ka bp until recent centuries and a subsequent recession that still continues

origin of late pleistocene bryozoan reef mounds great australian bight bryozoan rich biogenic mounds grew periodically on the prograding carbonate slope of the central great australian bight throughout pliocene pleistocene time cores from three odp leg 182 drill sites provide a record of mound growth during the last 300 000 years over a stratigraphic thickness of similar to 150 m these mounds the first such structures described from the modern ocean grew between paleodepths of 100 and 240 m we infer that the upper limit of growth was established by swell wave base and the lower boundary was fixed by an oligotrophic water mass detailed chronostratigraphy based on radiometric and u series dating benthic foraminifer stable isotope stratigraphy and planktonic foraminifer abundance ratios confirms that buildups flourished during glacial lowstands even numbered marine isotope stages but were largely moribund during interglacial highstands and are not extant today mound floatstones are compositionally a mixture of in situ bryozoans comprising 96 genera and characterized by fenestrate flat robust branching encrusting nodular arborescent and delicate branching growth forms the packstone matrix comprises autochthonous and allochthonous sand size bryozoans benthic and planktonic foraminifers serpulids coralline algae sponge spicules peloids and variable glauconite and quartz grains together with mud size ostracods tunicate spicules bioeroded sponge chips and coccoliths intermound allochthonous packstone and local grainstone contain similar particles but they are conspicuously worn abraded blackened and bioeroded an integrated model of mound accretion during sea level lowstands begins with delicate branching bryozoan floatstone that increases in bryozoan abundance and diversity upward over a thickness of 5 10 m culminating in thin intervals of grainstone characterized by reduced diversity and locally abraded fossils mound accumulation was relatively rapid 30 67 cm ky and locally punctuated by rudstones and firmgrounds intermound highstand deposition was comparatively slow 17 25 cm ky and typified by meter scale fining upward packages of packstone and grainstone or burrowed packstone with local firmgrounds overlain by characteristically abraded particles mound growth during glacial periods is interpreted to have resulted from increased nutrient supply and enhanced primary productivity such elevated trophic resources were both regional and local and thought to be focused in this area by cessation of leeuwin current flow together with northward movement of the subtropical convergence and related dynamic mixing

glaciations of the west coast range tasmania geomorphic stratigraphic palynologic and 14c evidence indicates that the west coast range tasmania was glaciated at least three times during the late cenozoic the last or margaret glaciation commenced after 30 000 yr b p culminated about 19 000 yr b p and ended by 10 000 yr b p during this period a small ice cap ca 250 m thick and cirque and valley glaciers covered 108 km2 the glacial deposits show little chemical weathering or erosional dissection the snow line ranged from 690 to 1000 m with an average of 830 m for the ice cap mean temperature was 6 5 c below the present temperature during the preceding henty glaciation a 300 to 400 m thick ice cap and outlet glaciers exceeded 1000 km2 the glacial deposits are beyond 14c assay they are more weathered chemically and more dissected than margaret age deposits and the degree suggests a pre last interglaciation age 130 000 yr b p the snow line of the ice cap lay at 740 m and annual temperature was reduced by 7 c ice of the earliest linda glaciation slightly exceeded that of the henty glaciation but had a similar distribution the glacial deposits are intensely weathered have reversed magnetization and overlie a paleosol containing pollen of tertiary type an early pleistocene or tertiary age is indicated

exposure ages for pleistocene periglacial deposits in australia abstract pleistocene periglacial landforms are widespread in australia and provide valuable information on past temperatures but dating the time of their formation has proven difficult to remedy this we have explored the use of cosmogenic 36 cl for direct dating of periglacial deposits we sampled six deposits in four locations in southeastern australia ranging from blockstreams and block slopes to former rock glaciers eighteen exposure ages reveal a concentration of periglacial activity during the last glacial maximum lgm between 16 and 23 ka with a population having a weighted mean age of 21 9 0 5 ka this age is shortly before the time of maximum ice advance during the lgm in southeastern australia exposure dating of block deposits provides a way of extending the chronology of cold climate activity beyond glaciated regions

lead isotopic evidence for an australian source of aeolian dust to antarctica at times over the last 170 000 years abstract systematic analysis of pb sr and nd isotopes of 32 fluvial clay samples 6 km 2 murray darling basin mdb located in semiarid southeastern australia displays similar isotopic values between some mdb clays and dust from several ice core samples from the epica dome c in antarctica close scrutiny of several ratios of the four pb isotopes and in particular 208 pb 207 pb versus 206 pb 207 pb shows that several samples from the darling sub basin of the mdb display similar values for the same isotopes for dome c samples from different ages and more particularly during wet phases in australia marine isotopic stages 5e 3 and 1 the combination of nd and sr isotopic ratios from the same mdb fluvial clays clearly eliminates the murray sub basin and supports the darling sub basin as a potential source of aeolian material to antarctica overall the australian dust supply to antarctica predominantly occurred during interglacial periods the work presented here shows that aerosols generated in southeastern australia can travel to parts of west antarctica and this is supported by atmospheric observations and models in addition evidence of australian dust in antarctic ice cores further implies dust deposition in the southern ocean would have occurred in the past current meteorological observations also imply that the western pacific and indian ocean sector of the southern ocean would frequently receive aeolian dust components originating from southeastern australia

oceanographic and climatic changes over the past 160 000 years at deep sea drilling project site 594 off southeastern new zealand southwest pacific ocean high resolution textural carbonate microfossil and oxygen 18o and carbon 13c stable isotopic analyses are presented for the late quaternary isotopic stages 1 to 6 interval of a core at deep sea drilling project site 594 situated just south of the present subtropical convergence in northernmost subantarctic surface waters on the southern flank of chatham rise in the southwest pacific downcore alternations of pelagic and hemipelagic oozes correspond to interglacial and glacial episodes respectively interglacial oozes contain a northern subantarctic assemblage of planktonic foraminifera with rare cool subtropical species while glacial oozes are characterized by species typical of southern most subantarctic waters and include radiolaria with affinity for antarctic waters the planktonic 18o record for the site supports a 3 6 c temperature change in near surface waters between interglacial and glacial stages and indicates that during stage 5e the near surface waters were about 1 c warmer than at present a pronounced cooling during stage 5d matches that of the vostok ice core d record and negative excursions at the end of stages 2 and 6 support a southern latitude warming preceding northern hemisphere deglaciation benthic foraminifera typical of cold intermediate to deep waters can increase dramatically in abundance in the hemipelagic ooze intervals when 18o results suggest a temperature drop in glacial stage bottom waters of 2 4 c possibly a result of upward displacement of antarctic intermediate water by circumpolar deep water at the site the foraminiferal 13c records support a reduced influence of north atlantic deep water in the southwest pacific during glacial stages when nutrient enhancement occurred in both bottom and surface waters despite the pronounced changes between interglacial and glacial conditions inferred at site 594 contributed to by a substantial northward shift by at least 5 of latitude in the position of the antarctic convergence south of new zealand during glacial episodes we conclude that the subtropical convergence remained locked to chatham rise approximately 44 s throughout stages 1 to 6 major compression of the intervening belt of subantarctic water during glacial episodes and the associated very steep thermal gradients and intensified atmospheric and oceanic circulation patterns that developed in this part of the southwest pacific account for the harsh frigid environment reported for on land southern new zealand at these times

growth rates of icicles experimental and theoretical studies on the growth rate of an icicle were carried out as a function of temperature water supply rate and wind speed the relative humidity was also taken into account the length of an icicle increases by the downward growth of thin dendritic crystals into the supercooled pendant water drop at the tip and thus the growth is in the crystallographic a axis direction the diameter on the other hand increases by the freezing of a water film flowing down along the icicle wall the ratio of measured length and diameter growth rates was large namely 8 32 both growth rates increased with decreasing temperature and increasing wind speed the increase in water supply rate led to the decrease in the length growth rate but no significant change in the diameter growth rate these results could be well described by a numerical model of icicle growth which takes account of the dendritic growth at the tip and the wall and the effective heat transfer within the turbulent boundary layer around the icicle a formation mechanism of ribs and hollows is discussed in relation to the flowing and freezing process of water on an icicle wall

the last glacial maximum in central and southern north island new zealand a paleoenvironmental reconstruction using the kawakawa tephra formation as a chronostratigraphic marker abstract kawakawa tephra formation comprising oruanui ignimbrite flow member and aokautere ash airfall member represents the products of an exceptionally large and widespread volcanic eruption from taupo volcanic centre in the north island of new zealand the eruption occurred during the last glacial maximum and is radiocarbon dated at c 22 6 ka b p thermoluminescence ages are in broad agreement with the radiocarbon age the presence of aokautere ash in loess deposits in alluvial gully fills on river terraces and its absence from unstable sites permits a detailed assessment of geomorphic activity during the last glacial maximum widespread erosion of regolith aggradation of river valleys and deposition of loess particularly in the period following eruption of the kawakawa point to a cold dry variable climate a collation of pollen data for sediments containing aokautere ash and those 14c dated in the range 17 23 ka shows that tall forest was highly restricted in the central and southern parts of the north island an apparently subalpine grassland shrubland was present at sites from present sea level to over 800 m elevation suggesting that factors other than lower temperatures such as exposure to wind and frost fire and reduced rainfall were important in controlling vegetation patterns we conclude that the interval 23 13 ka b p broadly equivalent to oxygen isotope stage 2 represents the period of greatest environmental change in the north island

reevaluation of the oxygen isotopic composition of planktonic foraminifera experimental results and revised paleotemperature equations cultured planktonic foraminifera orbulina universa symbiotic and globigerina bulloides nonsymbiotic are used to reexamine temperature 18o relationships at 15 25 c relationships for both species can be described by linear equations equations for o universa grown under low light ll and high light hl share a slope of 4 80 0 21 c 1 with a hl ll offset of 0 33 due to symbiont photosynthetic activity the effect of co32 on o universa is 0 002 mol 1 kg 1 and is insensitive to temperature for g bulloides ontogenetic effects produce size related trends in temperature 18o whereby larger shells are enriched in 18o relative to smaller specimens the o universa temperature 18o relationships are more accurate than previously published equations for describing plankton tow data our equations do not explain planktonic core top data with the same precision but provide a good fit to benthic cibicidoides data below 10 c temperature 18o relationships for g bulloides provide good agreement with field data for this species from the northeast pacific

the late quaternary calcareous nannoplankton assemblages from three cores from the tasman sea abstract the composition of the late quaternary calcareous nannoplankton in three deep sea cores rc12 113 z 2108 and gc 3 located along a n s transect at three different latitudes 25 33 44 s in the tasman sea has been investigated the shift in floral dominance from small gephyrocapsa to small placoliths labelled here small placolith and then to emiliania huxleyi is recognized at stage 5 and stage 4 respectively in cores rc12 113 and z 2108 however the occurrence of small gephyrocapsa and small placolith displays a seesaw relationship in core gc 3 which is located today just north of the subtropical convergence east of tasmania gephyrocapsa muellerae and coccolithus pelagicus increase their abundance geographically southwards and stratigraphically during glacial periods whereas the percentage abundances of florisphaera profunda and umbilicosphaera sibogae demonstrate reverse patterns the relationships between the percentage abundance of each nannoplankton species and the 18 o record for three cores are discussed in detail a transfer function for estimating past sea surface temperatures tn is attempted here it is based on core top data from the tasman sea and provides a good relationship between some calcareous nannoplankton assemblages and modern mean summer sea surface temperatures the tn value shows a good correspondence with the 18 o record in all three cores core gc 3 is much affected by caco 3 dissolution in comparison with cores rc12 113 and z 2108 the calcareous nannoplankton dissolution patterns recognized in the three cores do not show a systematic correspondence with the 18 o record of interest however is the good preservation peaks that are recognized in all three cores at the transitions from glacial to interglacial events

the last deglaciation in the southern ocean the isotopic and micropaleontological deglacial records of three deep sea cores from 44 s to 55 s have been dated by accelerator mass spectrometry the available records did not allow accurate dating of the initiation of the deglaciation by 13 000 years b p sea surface temperatures reached values similar to the present values a cool oscillation abruptly interrupted this warm phase between 12 000 and 11 000 years b p initiation of this cooling therefore preceded the northern hemisphere younger dryas by approximately 1000 years complete warming was reached by 10 000 years b p more or less synchronous with the northeast atlantic ocean

changes in the position of the subtropical front south of new zealand since the last glacial period this study fills an important gap in our understanding of past changes in the southern subtropical front s stf in the southwest pacific ocean paleo sea surface temperatures sst were estimated from planktic foraminiferal census counts from cores straddling the modern s stf in the solander trough south of new zealand the estimated sst were compared for 6 time slices glacial period 25 21 ka last glacial maximum lgm 21 18 ka early deglaciation 18 16 ka late deglacial early holocene period 14 8 ka mid holocene period 8 4 ka and late holocene period 4 0 ka the position of the s stf was determined by two methods 1 the location of the 10 degrees c isotherm and 2 the location of the highest sst gradients these new results suggest that the s stf was not continuous between east and west of new zealand during the glacial period steep sst gradients indicate that a strong s stf rapidly shifted south during the lgm and early deglaciation during the late deglacial and holocene periods the position of the s stf differs between the two methods with reduced sst gradients suggesting amore diffuse s stf in the solander trough at this time the glacial sst data suggest that the s stf shifted north to the west of new zealand while to the east there was a stronger sst gradient across the front this was possibly the result of an increased wind stress curl which could have been caused by stronger or more northerly southern hemisphere westerly winds shww or a merging of the shww split jet in this region

sea surface temperatures of the southwest pacific ocean during the last glacial maximum the southwest pacific ocean covers a broad range of surface water conditions ranging from warm salty water in the subtropical east australian current to fresher cold water in the circumpolar current using a new database of planktonic foraminifera assemblages ausmat f2 we demonstrate that the modern analog technique can be used to accurately reconstruct the magnitude of sea surfacetemperature sst in this region we apply this technique to data from 29 deep sea cores along a meridional transect of the southwest pacific ocean to estimate the magnitude of sst cooling during the last glacial maximum we find minimal cooling in the tropics 0 2 c moderate cooling in the subtropical midlatitudes 2 6 c and maximum cooling to the southeast of new zealand 6 10 c the magnitude of cooling at the sea surface from the tropics to the temperate latitudes is found to generally be less than cooling at the surface of adjacent land masses

oxygen isotope constraints on surface ocean temperatures published oxygen isotope results from benthic and planktonic foraminifera are used to constrain the extent to which surface ocean temperatures in the tropics changed between glacial and interglacial time the possible impacts of bioturbation and of the redistribution of 18o16o ratios within the sea putting aside the oxygen isotope results are consistent with the climap project conclusion that tropical ocean temperatures remained within 2 c of their present value

the timing of the last glacial maximum in australia abstract late pleistocene glaciation of australia was restricted to the snowy mountains and the tasmanian highlands glaciers were most extensive in tasmania where ice caps formed on the central plateau and west coast ranges and systems of valley and cirque glaciers formed on surrounding mountains to investigate the timing of maximum glacier advance during the last glacial maximum lgm we dated boulders on 18 moraines in 8 glaciated areas using cosmogenic 36cl and 10be we sampled moraines deposited by cirque and valley glaciers in a range of climate types and lithologies over a 7 latitudinal and a 1430 m altitudinal transect exposure ages for lgm moraine boulders group tightly in the range 17 20 ka boulders from the hamilton moraine often treated as the lgm type moraine range in age from 190 350 ka indicating that it was deposited well before the last glaciation collectively the exposure ages show that southeastern australia was glaciated briefly during and after the lgm and deglaciated well before the holocene ice retreated from the terminal moraines after the period of coldest sea surface temperatures in the southwest pacific ocean no evidence was found for readvance of glaciers during the antarctic cold reversal or the younger dryas period

a review of the australian new zealand sector of the southern ocean over the last 30ka aus intimate project the australia new zealand region of the southern ocean is influenced by several of the major global water masses of the oceans and is the prime entry point for cold deep waters into the pacific basin during the last glacial there was increased sea ice extent around antarctica as far north as 55 s as well as increased iceberg presence inferred from ice rafted debris evidence from microfossil assemblages suggests that sea surface temperatures sst were up to 7 c cooler consistent with recent estimates of cooling for new zealand derived from glacier modelling and other terrestrial proxies the subtropical front stf subantarctic front saf and polar front pf had migrated north except where the position of the fronts were controlled bathymetrically despite the potential for iron fertilisation by increased dust input into the ocean during the glacial there is limited evidence for higher total biological productivity in the pacific sector of the southern ocean the altered oceanic circulation during the glacial also decreased nutrients in the surface waters and affected the outgassing of co 2 this contributed to an increased storage of co 2 in the deep waters and lowering of the carbonate lysocline during the deglaciation sea ice retreat and sst increased rapidly at 18 ka roughly synchronous with the reinvigoration of deep water circulation in the southern ocean and the release of co 2 stored in the deep waters the gradient in carbon isotopes 13 o benthic between antarctic intermediate water aaiw and lower circumpolar deep water lcdw was greatest at the start of the deglaciation suggesting that the aaiw ventilation preceded lcdw ventilation or there was a significant change in air sea fractionation of 13 o benthic there was a slight enrichment in 18 o planktic decrease in ssts and a reduction in intermediate and deep water circulation between 14 and 12 5 ka bp during the antarctic cold reversal acr coincident with glacier advances in the new zealand southern alps and other terrestrial records of cooling following the acr there was a second more minor release of deep water co 2 most likely related to reinvigoration of north atlantic deep water nadw from 10 ka onwards the modern intermediate and deep water circulation was established air temperatures and ssts reached a maximum in the early holocene with the stf located at its most southerly position and there was a widespread retreat of antarctic ice sheets to their modern position a decline to modern sst and air temperatures in the mid to late holocene followed while millennial cycles overprinted on the sst and 18 o planktic records may be the result of subtle changes in the position and strength of the westerly winds during the holocene

the late quaternary peat vegetation and climate history of the southern oceanic islands of new zealand abstract seven oceanic island groups chatham bounty snares antipodes auckland campbell and macquarie lie to the south and east of the southern new zealand mainland between the subtropical convergence and the antarctic convergence they are highly oceanic experiencing moist cool cloudy and windy climates deep peat soils cover most of the islands except for steep slopes and exposed high altitude sites the three large island groups chatham auckland and campbell support forest and tall scrub in the lowlands in the latter two grading with altitude through shrubland and grassland to upland tundra macrophyllous forbs create luxuriant herbfields in nutrient rich coastal sites and also as stunted forms dominate upland tundra associations the southernmost island macquarie has no woody species and is covered with tussock grassland herbfield and tundra vegetation cover is highly sensitive to soil saturation and exposure to the strong westerly winds of this region extensive oligotrophic bogs occur where drainage is poor and exposure high and forest and tall scrub are abundant only in sheltered well drained lowland sites glacial cirque levels indicate mean annual temperatures fell by 5 6 c during the last glacial maximum a depression of 6 10 c in sea surface temperatures is suggested by deep sea core analyses but this seems incompatible with terrestrial evidence auckland and campbell islands were extensively glaciated and grassland herbfield and tundra landscapes prevailed glaciers retreated by 15 000 yr bp and landscapes had stabilised and peat soils begun forming by 12 000 yr bp by the beginning of the holocene oligotrophic bog grassland and shrubland were dominant scrub and low forest spread slowly during the early holocene in the chatham auckland and campbell islands inhibited by cloudy moist climates low insolation and wet soils maximum extent of forest and scrub occurred between 6000 and 2000 yr bp most probably linked with a drying of the soils and increasing summer insolation upland sites and those exposed to westerly gales on auckland and campbell islands remained in grassland herbfield and bog throughout the holocene wind blown sand and stones in cliff edge peat profiles on auckland and campbell island from 8000 yr bp suggest strengthening westerly winds

thermal isolation of campbell plateau new zealand by the antarctic circumpolar current over the past 130 kyr 1 campbell plateau occupies a key position in the southwest pacific sector of the southern ocean the plateau confines and steers the antarctic circumpolar current acc along its flanks isolating the subantarctic plateau from cold polar waters oxygen and carbon isotope records from campbell plateau cores provide new records of water mass stratification for the past 130 kyr during glacial climes strengthening of the subantarctic front saf caused waters over the plateau flanks to be deeply mixed and 3 c cooler waters of the plateau interior remained stratified and isolated from the cold southern waters in the west waters cooled markedly 4 c owing to reduced entrainment of tasman sea water marked cooling also occurred north of campbell plateau under increased entrainment of polar water by a branch of the saf the acc remained along the flanks of campbell plateau during the last interglacial when interior waters were stratified and warmer by 1 c than now

an integrated latest quaternary stage 3 to present paleoclimatic and paleoceanographic record from offshore northern new zealand abstract paleoceanographic and onshore paleoclimatic changes during the last 59 000 yr are established from three deep sea sediment cores off northeast new zealand using an integrated log of sediment texture caco3 content palynology and planktonic and benthic foraminiferal 18o and 13c data together with dated silicic tephras these records from the isotopic stage 4 3 boundary to the present record northern new zealand vegetation history changes in a subsidiary equatorward flow of circumpolar deep water and sea surface temperatures ssts for subtropical water stw between latitudes 36 42 and 35 51 s relative to the holocene isotopically derived ssts record average changes of 2 c 2 c and 2 c for the 59 000 43 000 43 000 24 000 and 24 000 12 000 yr time slices respectively the apparent 2 c warming for the 59 000 43 000 yr period is interpreted to reflect changes in the dominant depth habitat of globigerina bulloides in response to upwelling a 2 c cooling of ssts during isotope stage 2 is interpreted in part to reflect upwelling of cool subsurface water resulting from strong and persistent westerly airflow across new zealand with the concomitant enhanced surface water production of caco3 onshore vegetation consistent with these changes are recorded with full conifer hardwood forest prior to 43 000 yr followed by a change to vegetation implying cooler and drier conditions between 43 000 and 12 000 yr and a subsequent return to full forest during the holocene the sequence of biopelagic and hemipelagic sedimentation observed within these cores reflect oscillation of sea level about a threshold eustatic level that controls the transport of terrigenous detritus offshore local variations and interplay of the regional oceanography and morphology and tectonism of the continental shelf will dictate that relative to present sea level this threshold eustatic sea level will vary in depth and hence age along a continental margin data from the new zealand region reveal an extremely steep meridional thermal gradient across the southern and central new zealand region during the last glaciation with minor cooling of stw to the north apart from localized nearshore upwelling zones but pronounced cooling of subantarctic water to the south of the subtropical convergence zone

planktonic foraminifera in the western north pacific during the past 150 000 years comparison of modern and fossil assemblages abstract planktonic foraminiferal abundance variations in 186 deep sea piston core tops from the western north pacific were used to create a calibration set to characterize the present day kuroshio gyre system q mode factor analysis helped identify six faunal assemblages 93 variance related to modern water masses two tropical assemblages differing in relative dissolution three assemblages representing subtropical subpolar and transitional conditions and a gyre margin assemblage lying between the kuroshio current and the mainland of asia multivariate regression produced transfer functions relating observed summer august and winter february sea surface temperatures sst to the assemblages with standard errors of estimate of 1 5 c and 2 5 c respectively data from 24 piston cores was used to interpret variations of the kuroshio gyre system during the past 150 000 yr stratigraphic control is based on oxygen isotopic measurements the extinction of pink pigmented globigerinoides ruber at 120 000 b p coiling direction changes in neogloboquadrina pachyderma north of 30 n and dissolution variations between resistant and fragile taxa major dynamic changes in the circulation of the kuroshio gyre occurred during the last two glacial maxima at 15 20 000 b p isotopic stage 2 and at 140 150 000 b p isotopic stage 6 these intervals are characterized by 1 lowered sea levels which reduced flow into the sea of japan and sea of okh okhotsk 2 advance of the polar front from its modern position at about 42 n to 35 38 n 3 southward penetration of the oyashio current along the pacific coast of japan to tokyo 4 2 3 c lowered sst in tropical areas little or no change in subtropical areas and a 4 6 c decrease in transitional areas and 5 an overall decrease in carbonate dissolution relative to interglacial stages the maximum interglacial at 120 000 b p isotopic substage 5e shows a retreat of the polar front north of its modern position and an overall relative increase in interglacial carbonate dissolution that does not become severe until substage 5d

the tasman front a study using satellite infrared imagery abstract monthly charts of the approximately zonal tasman front between the australian coast near 152 e and 164 e and between latitudes 31 to 37 s have been constructed from infrared satellite imagery for 29 months from march 1982 to april 1985 from these it was found that one to three meanders but usually two are present between 152 and 164 e and that the second meander pinches off at times to form a warm core ring in the same manner as is known to occur for the first meander both second meander and ring tend to propagate westwards the mean zonal widths of the first and second meander are similar and are 3 6 to 3 7 longitude 330 345 km the average and the most likely modal positions of the tasman front were determined and the two positions are most different when the front meanders northward the zonal length scale of frontal perturbations increases eastward from 140 near 155 e to 300 km near 161 e and perturbations propagate westward at approximately 0 1 m s 1

sea surface temperatures around the australian margin and indian ocean during the last glacial maximum abstract we present new last glacial maximum lgm sea surface temperature sst maps for the oceans around australia based on planktonic foraminifera assemblages to provide the most reliable sst estimates we use the modern analog technique the revised analog method and artificial neural networks in conjunction with an expanded modern core top database all three methods produce similar quality predictions and the root mean squared error of the consensus prediction the average of the three under cross validation is only 0 77 c we determine lgm sst using data from 165 cores most of which have good age control from oxygen isotope stratigraphy and radiocarbon dates the coldest sst occurred at 20 500 1400 cal yr bp predating the maximum in oxygen isotope records at 18 200 1500 cal yr bp during the lgm interval we observe cooling within the tropics of up to 4 c in the eastern indian ocean and mostly between 0 and 3 c elsewhere along the equator the high latitudes cooled by the greatest degree a maximum of 7 9 c in the southwest pacific ocean our maps improve substantially on previous attempts by making higher quality temperature estimates using more cores and improving age control

climatic variability in the southwest pacific during the last termination 20 10 kyr bp the degree to which palaeoclimatic changes in the southern hemisphere co varied with events in the high latitude northern hemisphere during the last termination is a contentious issue with conflicting evidence for the degree of teleconnection between different regions of the southern hemisphere the available hypotheses are difficult to test robustly however because there are few detailed palaeoclimatic records in the southern hemisphere here we present climatic reconstructions from the southwestern pacific a key region in the southern hemisphere because of the potentially important role it plays in global climate change the reconstructions for the period 20 10 kyr bp were obtained from five sites along a transect from southern new zealand through australia to indonesia supported by 125 calibrated c 14 ages two periods of significant climatic change can be identified across the region at around 17 and 14 2 cal kyr bp most probably associated with the onset of warming in the west pacific warm pool and the collapse of antarctic ice during meltwater pulse 1a respectively the severe geochronological constraints that inherently afflict age models based on radiocarbon dating and the lack of quantified climatic parameters make more detailed interpretations problematic however there is an urgent need to address the geochronological limitations and to develop more precise and quantified estimates of the pronounced climate variations that clearly affected this region during the last termination c 2005 elsevier ltd all rights reserved

tropical pacific ocean thermocline depth reconstructions for the last glacial maximum we evaluate the relationship between ten surface ocean 0 300 m hydrographic parameters and the spatial distribution of factor analyzed core top planktonic foraminiferal abundances in the tropical pacific ocean 24 n 24 s for core tops 3800 m the spatial distribution of the first three faunal factor loadings 88 of the variance are most highly correlated to subsurface variability mixed layer depth thermocline depth and resistant species percent rsp however rsp is not related to dissolution but is related to thermocline depth factor i mixed layer species g glutinata g ruber and factor iii g ruber can be distinguished from each other by low abundances of g glutinata in factor iii both assemblages spatially comprise the deep mixed layer region of the western tropical and equatorial pacific ocean but are associated with distinct water mass properties a combination of factor i and iii loadings shows a higher correlation to thermocline depth r 0 70 factor ii loadings dominated by thermocline dwelling species n dutertrei are most significantly correlated with the thermocline depth r 0 73 most factors show only marginally significant correlation to sea surface temperatures ssts indicating that sst is not the primary forcing factor on the planktonic foraminiferal species distributions in the tropical pacific a new transfer function was calculated to predict tropical pacific thermocline depth from planktonic foraminifera abundances using the imbrie kipp method ikm standard deviation of residuals 22 m 1 an additional 5 m error is attributed to low species counts in the core top database the modern analog technique mat was also used to predict thermocline depth standard deviation of residuals 21 m while last glacial maximum lgm thermocline depth changes by ikm and mat were generally within error estimated changes were geographically uniform suggesting an oceanographic response to climate forcing we estimate that the thermocline depth of the lgm was shallower than present by 20 m south of 8 s possibly due to a shift in the south pacific anticyclone to the northeast both the ikm and mat estimate a steeper east west thermocline slope along the equator suggesting that zonal wind stress walker circulation was intensified during the lgm collectively the thermocline estimates for the lgm suggest an equatorward compression of the climate zones in both hemispheres

planktic foraminifera based sea surface temperature record in the tasman sea and history of the subtropical front around new zealand over the last one million years abstract planktic foraminiferal assemblages in a composite section from two cores md06 2989 2986 off the west coast of new zealand s south island 42 43 5 s provide a 1 myr mis 31 1 sea surface temperature sst record 3 4 kyr resolution in the tasman sea a significant overall faunal change occurred near the end of the mid pleistocene climate transition mpt at 600 ka mis 15 mean annual ssts were estimated using the artificial neural network ann method glacial interglacial g i cycles in the mpt had 9 c sst range whereas in the post mpt sst range was 6 7 c the sst and faunal changes imply that the subtropical front stf migrated 6 in latitude to lie just north of the sites in mpt glacials mis 28 16 but only migrated 3 5 north in post mpt glacials these g i latitudinal migrations of the stf west of new zealand contrast with the situation east of new zealand where migrations of both the stf and subantarctic front were prevented by the chatham rise and campbell plateau subtropical water is inferred to have only flowed around the south of new zealand as it does today during mis 11 and the late pleistocene holocene mis 5 1

response of nannoplankton to major changes in sea surface temperature and movements of hydrological fronts over site dsdp 594 south chatham rise southeastern new zealand during the last 130 kyr abstract a high resolution history of paleoceanographic changes in the subpolar waters of the southern margin of the subtropical convergence zone during the last 130 kyr is present in foraminiferal assemblages of dsdp site 594 the foraminifera indicate that sea surface temperatures during the last interglacial climax were warmer than today and that between substage 5d through to the end of isotope stage 2 temperatures were mostly cooler than holocene temperatures the paleotemperatures suggest that 1 the subtropical convergence was located over the site during substage 5e later moving further north then moving southwards to near the site during the holocene and 2 the polar front was positioned over the site during glacial stages 6 4 2 and possibly parts of stage 3 several major events are indicated by the nannofloral assemblages during these large changes in sea surface temperature and associated reorganization of ocean circulation first the time progressive trends between e huxleyi and medium to large gephyrocapsa are unique to this site with e huxleyi dominating over medium gephyrocapsa during stages 5c a middle part of stage 4 and after the middle point of stage 3 this unusual trend may at least partly be caused by the shift of the polar front across the site second upwelling flora e huxleyi and small placoliths increase in abundance during stages 1 3 and 5 suggesting that upwelling or disturbance of water stratification took place during the interglacials thirdly there are no significant differences between the distribution patterns of the various morphotypes of medium to large gephyrocapsa and the combined value of all medium gephyrocapsa increases in abundance during glacials stages 2 and 4 and the end of stage 6 similar to the abundance trends in benthic foraminifera finally subordinate nannofossil taxa also show distinctive climatic trends during the last glacial cycle 1 syracosphaera spp are present in increased abundance during warmer extremes in climate substages 5e 5a and stage 1 2 coccolithus pelagicus and calcidiscus leptoporus dominate the subordinate nannofossil taxa and their relative proportions seem to provide a useful paleoceanographic index with c pelagicus dominating when the polar front zone is over the site stages 6 4 and 2 whilst c leptoporus is relatively more abundant when the stc is positioned over the site stages 1 and 5e increased abundance of c pelagicus also can indicate intensified coastal upwelling

abrupt changes in early holocene tropical sea surface temperature derived from coral records for many high latitude regions of the globe it is now clear that the transition to modern climate following the last glacial maximum was punctuated by a number of rapid and substantial climate oscillations1 2 in contrast relatively little is known about how the tropics responded to the deglaciation because few high resolution records are available from lower latitudes corals have recently been shown to provide an important source of tropical climate records because they can be easily and accurately dated using either 14c or 230th and because past sea surface temperatures can be recovered from the sr ca ratios in coral skeletons here we use this technique to derive several early holocene sea surface temperature records from a coral drill core recovered from espiritu santo vanuatu in the tropical southwest pacific ocean these records indicate that sea surface temperatures in this region were depressed by as much as 6 5 c below modern values at 10 350 calendar years bp but rose very abruptly during the following 1 500 years this temperature increase lags the post younger dryas increase observed in a coral record from the tropical atlantic ocean3by about 3 000 years an unexpected phase shift that may ultimately shed light on the mechanisms of deglacial climate change

south tasman sea alkenone palaeothermometry over the last four glacial interglacial cycles alkenone palaeothermometry has demonstrated a wide spatial and temporal applicability for the reconstruction of sea surface temperatures sst some oceanic realms however remain poorly studied we document u37 index data for two sediment cores retrieved from the south tasman sea one west of new zealand so136 gc3 and the other southeast of tasmania fr1 94 gc3 extending back 280 kyr bp for the former and 460 kyr bp for the latter high climatic sensitivity on orbital time scales is observed at both locations particularly west of new zealand where typical glacial interglacial sst amplitudes always span more than 7 c southeast of tasmania sst amplitudes are lower in amplitude 4 3 to 6 9 c with the exception of termination iv which involved a sst change over 8 c the evolution of maximum glacial cooling through time is different at each location offshore new zealand maximum cooling during glacial stages increases with time whereas south of tasmania maximum cooling decreases with time in addition our data suggest heterogeneity in the spatial expression of sst during the penultimate and last glacial stages these glacial periods are recorded differently in both areas with marine isotopic stage 6 being warmer than marine isotopic stage 2 west of new zealand but slightly colder southeast of tasmania the area southwest of new zealand appears susceptible to expansions and contractions of the western pacific warm pool and or meridional migrations and changes in intensity of currents associated with the tasman front the region southeast of tasmania seems more sensitive to thermal changes as seen at high southern latitudes

comparison of foraminiferal coccolithophorid and radiolarian paleotemperature equations assemblage coherency and estimate concordancy the imbrie kipp method of paleotemperature estimation is rigorously tested by comparing atlantic temperature equations independently derived from the microfossils of three biotic groups the foraminifera coccolithophorida and radiolaria this method consists of two steps factor analysis of the modern sea bed data of the individual groups which resolves discrete biogeographic assemblages and regression analysis of the modern assemblage data with observed sea surface temperature data to obtain paleotemperature equations assemblage biogeography shows a simple subdivision into warm low latitude and cold high latitude for all biotic groups between biotic groups there is greater similarity among high latitude assemblages than low latitude ones correlating the assemblage data with observed sea surface temperatures to produce temperature distribution patterns shows differences of less than 2 c in their optimum and critical temperatures regression analysis produced accurate temperature equations for each biotic group all with standard errors of estimate of less than or equal to 2 c multiple correlation coefficients were all greater than 0 970 applying these equations to two multiple biotic data sets the modern and ice age sea bed data and comparing their temperature estimates using the standard error pooled shows over 87 concordancy for both data sets unlike the modern data the discordancy among temperature estimates of the ice age data shows a distinct geographic distribution its cause is believed to be oceanographic a difference in the water mass structure between the modern and ice age ocean

high resolution climate simulation of the last glacial maximum the climate of the last glacial maximum lgm is simulated with a high resolution atmospheric general circulation model the ncar ccm3 at spectral truncation of t170 corresponding to a grid cell size of roughly 75 km the purpose of the study is to assess whether there are significant benefits from the higher resolution simulation compared to the lower resolution simulation associated with the role of topography the lgm simulations were forced with modified climap sea ice distribution and sea surface temperatures sst reduced by 1 c ice sheet topography reduced co2 and 21 000 bp orbital parameters the high resolution model captures modern climate reasonably well in particular the distribution of heavy precipitation in the tropical pacific for the ice age case surface temperature simulated by the high resolution model agrees better with those of proxy estimates than does the low resolution model despite the fact that tropical ssts were only 2 1 c less than the control run there are many lowland tropical land areas 4 6 c colder than present comparison of t170 model results with the best constrained proxy temperature estimates noble gas concentrations in groundwater now yield no significant differences between model and observations there are also significant upland temperature changes in the best resolved tropical mountain belt the andes we provisionally attribute this result in part as resulting from decreased lateral mixing between ocean and land in a model with more model grid cells a longstanding model data discrepancy therefore appears to be resolved without invoking any unusual model physics the response of the asian summer monsoon can also be more clearly linked to local geography in the high resolution model than in the low resolution model this distinction should enable more confident validation of climate proxy data with the high resolution model elsewhere an inferred salinity increase in the subtropical north atlantic may have significant implications for ocean circulation changes during the lgm a large part of the amazon and congo basins are simulated to be substantially drier in the ice age consistent with many but not all paleo data these results suggest that there are considerable benefits derived from high resolution model regarding regional climate responses and that observationalists can now compare their results with models that resolve geography at a resolution comparable to that which the proxy data represent

the record of continental dust from australia in tasman sea sediments abstract the flux of aeolian dust from australia to sediments of the tasman sea has increased during glacial stages of the last four glacial cycles low fluxes of dust from australia before 350 ka were followed by an increase in stage 10 and high fluxes in peak glacial periods thereafter the initiation of higher dust fluxes in stage 10 is consisten with previous estimates of the age of onset of aridity in the source area dust flux to the tasman sea is thought to record the intensity of deflation from the source area in interior southeastern australia which was marked by arid conditions and possibly greater windiness during the last glacial a transect of five cores from the central tasman sea revealed consistently low dust fluxes north of 33 s increasing southward to approximately 40 s glacial to interglacial movement of the northern boundary of the dust plume governed by the position of the subtropical ridge was less than 6 latitude probably closer to 3 350 km the position of the dust plume determined in this study and its response to climate change are significantly different from a previous reconstruction based on the measurement of quartz content of the non biogenic sediment fraction

benthic foraminiferal proxy evidence for the neogene palaeoceanographic history of the southwest pacific east of new zealand abstract canonical correspondence analysis indicates that the distribution of neogene benthic foraminiferal faunas 63 m in seven dsdp and odp sites 500 4500 m water depth east of new zealand 38 51 s 170 e 170 w is most strongly influenced by depth water mass stratification and secondly by age palaeoceanographic changes influencing faunal composition and biotic evolution stratigraphic faunal changes are interpretted in terms of the pulsed sequential development of southern and later northern polar glaciation and consequent cooling of bottom waters increased vertical and lateral stratification of ocean water masses and increased overall and seasonal surface water productivity oligocene initiation of the antarctic circumpolar current and deep western boundary current dwbc flowing northwards past new zealand resulted in extensive hiatuses throughout the southwest pacific some extending through into the miocene planktic foraminiferal fragmentation index values indicate that carbonate dissolution was significant at abyssal depths throughout most of the neogene peaking at upper abyssal depths in the late miocene 11 7 ma with the lysocline progressively deepened thereafter miocene abyssal faunas are dominated by globocassidulina subglobosa and oridorsalis umbonatus with increasing epistominella exigua after 16 ma at upper abyssal depths peak abundances of epistominella umbonifera indicate increased input of cold southern component water to the dwbc at 7 6 ma faunal association changes imply establishment of the modern oxygen minimum zone upper circumpolar deep water in the latest miocene significant latitudinal differences between the benthic foraminiferal faunas at lower bathyal depths indicate the existence of an oceanic front along the chatham rise location of present subtropical front since the early late miocene at least with more pulsed productivity higher e exigua along the south side modern antarctic intermediate water faunal associations were established north of the chatham rise at 10 9 ma and south of it at 3 1 5 ma middle upper bathyal faunas on the campbell plateau are dominated by reticulate bolivinids during the early and middle miocene indicative of sustained productivity above relatively sluggish suboxic bottom waters faunal changes and hiatuses indicate increased current vigour over the campbell plateau from the latest miocene on surface water productivity food supply appears to have increased in three steps at times of enhanced global cooling marked by substantially increased relative abundance of 1 abditodentrix pseudothalmanni alabaminella weddellensis cassidulina norvangi 16 15 ma increased pulsed productivity 2 bulimina marginata f aculeata nonionella auris trifarina angulosa uvigerina peregrina 3 1 5 ma increased overall productivity and 3 cassidulina carinata 1 0 5 ma increased overall productivity three intervals of deep sea benthic foraminiferal taxonomic turnover are recognised 16 15 11 5 10 2 0 5 ma corresponding to intervals of enhanced global cooling and possible productivity changes the late pliocene middle pleistocene extinction associated with increasing northern hemisphere glaciation culminating in the middle pleistocene climatic transition was more significant in the study area than the earlier neogene turnovers

late pleistocene palaeocenography of the tasman sea implications for the dynamics of the warm pool in the western pacific quantitative analyses of planktonic foraminifera from 47 core top samples spatially distributed through the tasman sea and cores rc12 113 e36 23 dsdp sites 588 592 593 and odp site 828a from a n s transect supplemented with stable isotope analyses indicate that three planktonic foraminiferal assemblages defined by factor analysis on core top material correlated with three hydrographic modes defined on the basis of sea surface temperatures temperature profiles seasonal changes in temperature and mixed layer depth similar assemblages were found in down core material along the tasman sea transect that combined with semi quantitative analyses of foraminiferal assemblages provinces and the coiling ratio of globorotalia truncatulinoides allows reconstruction of the position of the tasman front or the subtropical divergence during the late brunhes chron the results indicate that the tasman front migrated from its present position at 30 s to 26 s during the last glacial maximum the northward migration of the tasman front may indicate a reduction in volume of the equatorial warm pool and or an increase in the strength of cool subtropical water masses the late pleistocene distribution of g truncatulinoides left coiling from appears to be related to the formation of subantarctic mode water thermostads this relationship may explain the evolutionary origin of this species in the southwest pacific at 2 4 ma simultaneously with the onset of late pliocene glaciations the past position of the subtropical convergence is reconstructed by means of coilingv directions in neogloboquadrina pachyderma the convergence apparently migrated slightly north of 43 s core e36 23 during glacial stages 6 10 and 12

antarctic deglacial pattern in a 30 kyr record of sea surface temperature offshore south australia 1 comparison of ice cores from greenland and antarctica shows an asynchronous two step warming at these high latitudes during the last termination however the question whether this asynchrony extends to lower latitudes is unclear mainly due to the scarcity of paleorecords from the southern hemisphere new data from a marine core collected off south australia 36s allows a detailed reconstruction of sea surface temperatures over the last termination this confirms the existence of an antarctic type deglacial pattern and shows no indication of cooling associated with the northern hemisphere yd event the sst record also provides a new comparison with the more extensive paleoclimatic data available from continental australia this shows a strong climatic link between onshore and offshore records for australia and to southern hemisphere paleorecords we also show a progressive sst drop over the last 6 5 kyr not seen before for the australian region citation calvo e c pelejero p de deckker and g a logan 2007 antarctic deglacial pattern in a 30 kyr record of sea surface temperature offshore south australia geophys res lett 34 l13707 doi 10 1029 2007gl029937

glacial interglacial changes in the east australian current the east australian current eac is the western boundary current of the south pacific gyre transporting warm tropical waters to higher southern latitudes recent modelling shows that the partial separation of the eac 32 s and the coupled formation of the tasman front 34 s are caused by a steep gradient in the zonally integrated wind stress curl analysis of oxygen isotope ratios 18o in the planktonic foraminifer globigerinoides ruber from sediment cores from the coral sea and tasman sea indicates that the eac separation shifted northward to between 23 and 26 s during the last glacial we suggest these results indicate a significant change in the pacific wind stress curl during the glacial given recent evidence for el nino like conditions in the pacific during the last glacial with a reduction in the east west sea surface temperature sst gradient we suggest that weaker trade winds combined with more northerly stronger westerlies were associated with a change to the wind stress curl which repositioned the eac separation and tasman front in contrast by 11 ka bp the eac separation was forced south of 26 s this southward shift was synchronous with a rapid warming of tropical ssts and the onset of a la nina like sst configuration across the tropical pacific it appears that the south pacific trade winds strengthened accordingly causing the eac to readjust its flow this readjustment of the eac marks the onset of modern surface ocean circulation in the southwest pacific but the present eac transport was only achieved in the late holocene after 5 ka bp

pore fluid constraints on the temperature and oxygen isotopic composition of the glacial ocean pore fluids from the upper 60 meters of sediment 3000 meters below the surface of the tropical atlantic indicate that the oxygen isotopic composition 18 o of seawater at this site during the last glacial maximum was 0 8 0 1 per mil higher than it is today combined with the 18 o change in benthic foraminifera from this region the elevated ratio indicates that the temperature of deep water in the tropical atlantic ocean was 4 c colder during the last glacial maximum extrapolation from this site to a global average suggests that the ice volume contribution to the change in 18 o of foraminifera is 1 0 per mil which partially reconciles the foraminiferal oxygen isotope record of tropical sea surface temperatures with estimates from barbados corals and terrestrial climate proxies

environmental processes of the ice age land oceans glaciers epilog knowledge of the state of the earth at the last glacial maximum lgm an interval around 21 000 years ago is an important benchmark for understanding the sensitivity of global environmental systems to change much progress in understanding climates of the lgm has occurred in the 20 years since the end of the climap project of the 1970s climate long range investigation mapping and prediction here we review this progress based on presentations and discussion at a rst open science meeting of the epilog project environmental processes of the ice age land oceans glaciers held in delmenhorst germany may 1999 we outline key controversies and document protocols for epilog contributions so that a new synthesis of the lgm earth can emerge as an open project of the world s community of scientists 2001 elsevier science ltd all rights reserved

the salinity contrast between the atlantic and pacific oceans during glacial time in today s ocean the salinity of low latitude surface waters in the pacific is on the average 1 per mil lower than in the atlantic oxygen isotope records for planktonic foraminifera suggest that an even larger salinity deficit may have existed for pacific surface water during glacial time if so the transport of water vapor from the atlantic to the pacific must have been as strong as or even stronger to balance the tendency toward salt buildup the atlantic would have had to export during glacial time waters saltier than it received from the other oceans

sea surface temperature estimates from the southwest pacific based on planktonic foraminifera and oxygen isotopes planktonic foraminiferal census data were collected on 34 surficial sediment samples from east of new zealand sea surface temperature estimates were derived from the data using the modern analogue technique mat and compared to data from climap s fa 20 equation they were also computed from oxygen isotope analyses of globigerina bulloides the temperature estimates compared well between the three methods and were found to correlate closely with the appropriate seasonal sea surface temperature as measured by satellite the foraminiferal assemblages and derivative temperatures clearly identify the major watermasses and oceanic fronts in the region and thus can be applied to palaeoceanographic analysis of southwest pacific sediments

late quaternary palaeoceanography near tasmania southern australia abstract this study of the palaeoceanographic record south of australia is based on two cores taken from lower circumpolar deep water depths core e27 30 located south of tasmania in water depth of 3552 m to the north of the present location of the subtropical convergence and core e55 6 from the continental margin off victoria at 2346 m depth in a region of very low surface productivity a preliminary examination of planktonic foraminiferal faunas in core e27 30 located south of tasmania provides a record of movement of the subtropical convergence through the late quaternary that is consistent with records elsewhere in the southeast indian ocean the convergence has been located equatorward of its present position through much of the late quaternary with poleward excursions in the holocene and at oxygen isotope stage 5e benthic foraminiferal faunas contrast strongly in the two cores despite their location at similar depths within the same water mass core e55 6 is largely dominated by deep infaunal taxa while core e27 30 has a high proportion throughout of epifaunal taxa the benthic foraminiferal fauna in core e27 30 is dominated by epistominella exigua known to feed directly on phytoplankton detritus in the modern deep sea abundances of that species coincide with the presence of the subtropical convergence at or near the site indicating that surface phytoplankton production has had a major influence on benthic productivity dissolution records in the two cores also differ markedly core e55 6 records a strong dissolution event in oxygen isotope stage 4 the cause of the event is not clear although it appears to be associated with increased productivity levels this pronounced dissolution event is not evident in core e27 30 suggesting either the event is localised or that the record in core e27 30 has been overprinted by the convergence the extent to which the records in the two cores vary emphasises the influence of frontal structures on core records in this region and the need to take this into account when investigating southern ocean history

a discontinuous ca 80 ka record of late quaternary environmental change from lake omapere northland new zealand we present an integrated record of environmental change from lake omapere northland new zealand based on palaeolimnological analysis of a 7 m long core and eight adjunct cores spanning part of the last 80 calendar cal ka the chronology was developed using tephrochronology palaeomagnetism and radiocarbon dating together with climato and palyno stratigraphy two of 14 tephra layers in the cores provide markers for correlating the record with other new zealand climato stratigraphic sequences deep sea cores and the global marine isotope record pollen diatom palaeomagnetic sedimentologic and pigment analyses show that lake omapere currently 2 m deep has had a discontinuous history occupying a shallow basin perched partly within old basalt lavas the initial alkaline lake formed towards the end of mis 5a at ca 80 cal ka presumably because of blockage of local drainage of a swampy alluvial floodplain inundating peat deposits and forest trees including kauri agathis australis the lake filled rapidly to a level 1 2 m above that at present such filling was probably unrelated to climate but a subsequent phase of variable but generally falling lake levels and increasing dystrophy may have been climatically controlled commencing during mis 4 and culminating in periods early in mis 3 when the lake became swampy or dry conditions of non deposition or non preservation obtained for most of the period after ca 55 cal ka rotoehu ash until formation of the modern lake approximately 600 700 cal years ago or soon after as indicated by the presence of tephra 1 identified in part as kaharoa tephra ad 1314 near the top of the core the modern lake originated possibly through damming of the western outlet as a consequence of accelerated erosion accompanying earliest polynesian deforestation an interpretation supported by maori oral tradition the pollen record indicates that beech nothofagus presumably n truncata was much more common in northland during the last glacial and that for this region the relative abundance of nothofagus vs agathis pollen serves as a better indicator of cooler versus warmer intervals during the quaternary than the ratio of tree to non tree pollen however it seems likely that moisture balance was a more critical factor than temperature in vegetation composition and distribution particularly during the lgm and the long periods of hiatus may also be linked to a drier climate than present correlation coefficients between the pollen curves confirm that several tree species halocarpus bidwillii h biformis and phyllocladus alpinus previously palynologically concealed within generic taxonomic groups occurred about two degrees latitude further north and at a much lower altitude than their current limits during cooler or drier phases of the last glacial a temperature depression in northland of 4 c at various times during the last glacial is inferred from these range expansions nevertheless the persistence of widespread forest cover suggests that the late pleistocene climate of northland was less severe than for most of the rest of new zealand and strengthens the argument for a heightened temperature gradient across northern new zealand during the last glacial

late quaternary paleoclimatic and paleoceanographic change over northern chatham rise new zealand four cores from the lower northwestern flank 3010 3726 m water depth of the chatham rise east of new zealand penetrated a post glacial to last glacial sequence of mainly hemipelagic muds an accurate time frame for this study is provided by well dated tephra layers and additional 14c dates a hiatus is detected at the core tops of all cores studied with the last 900 to 1000 years missing sedimentological and micropaleontological analyses reveal that 1 1 isotope stage 2 ended ca 15 000 yr b p after a transitional period with a fluctuating composition of planktonic foraminifera assemblages and fluctuating isotopic values more stable post glacial conditions were established at ca 10 000 yr b p 2 2 from the end of isotope stage 2 to isotope stage 1 accumulation rates of diatoms aeolian quartz and calcareous microfossils decreased stepwise by a factor of 10 4 and ca 1 5 respectively in response to decreasing wind intensities and upwelling 3 3 in spite of significant climatic and oceanographic changes from the last glacial to the present the chatham rise has remained the northern distributional boundary for endemic subantarctic diatoms this implies that east of new zealand the subtropical convergence has remained bound or close to the chatham rise during both glacial and post glacial times 4 4 sediments are slight influences of contour currents or turbidity currents are recognised only in sediments younger than 16 000 years

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

glacial interglacial sea surface temperature changes across the subtropical front east of new zealand based on alkenone unsaturation ratios and foraminiferal assemblages 0 are compared to those derived from foraminiferal assemblages using the modern analog technique in two of these cores reconstructions of sst in core tops and holocene sediments agree well with modern average summer temperatures of 18 c in subtropical waters and 14 c in subpolar waters with a 4 5 c gradient across the front down core u37 k 0 sst estimates indicate that the regional summer sst was 4 5 c cooler during the last glaciation with an sst of 10 c in subpolar waters and an sst of 14 c in subtropical waters temperature reconstructions from foraminiferal assemblages agree with those derived from alkenones for the holocene in subtropical waters reconstructions also agree with a glacial cooling of 4 to 14 c in contrast reconstructions for subantarctic pre holocene waters indicate a cooling of 8 c with glacial age warm season water temperatures of 6 c thus the alkenones suggest the glacial temperature gradient across the front was the same or reduced slightly to 3 5 4 c whereas foraminiferal reconstructions suggest it doubled to 8 c our results support previous work indicating that the stf remained fixed over the chatham rise during the last glacial maximum however the differing results from the two techniques require additional explanation a change in euphotic zone temperature profiles seasonality of growth or preferred growth depth must have affected the temperatures recorded by these biologically based proxies regardless of the specific reason a differential response to the environmental changes between the two climate regimes by the organisms on which the estimates are based suggests increased upwelling associated with increased winds and or a shallowing of the thermocline associated with increased stratification of the surface layer in the last glaciation index terms 4267 oceanography general paleoceanography 4850 oceanography biological and chemical organic marine chemistry 1050 geochemistry marine geochemistry 4835 4850 1055 geochemistry organic geochemistry keywords paleoceanography sea surface temperature alkenones southern ocean last glacial maximum

late quaternary sea surface conditions at dsdp hole 594 in the southwest pacific ocean based on dinoflagellate cyst assemblages investigation of organic walled dinoflagellate cyst distribution in 118 surface sediments from the southern ocean documents the relatively high diversity of cyst taxa 46 species and distinct cyst assemblages in relation to surface water masses and temperature gradient the antarctic water is characterised by the dominance of selenopemphix antarctica accompanied by brigantedinium spp and impagidinium pallidum the subantarctic water association consists mainly of nematosphaeropsis labyrinthus impagidinium paradoxum and impagidinium sphaericum whereas the subtropical water association is dominated by operculodinium centrocarpum and spiniferites membranaceus multivariate analyses non metric multidimensional scaling demonstrate the relationships with sea surface conditions and enable the application of the best analogue method on the southern ocean dinoflagellate cyst data base for reconstructing past sea surface conditions the dinoflagellate cyst record from dsdp 594 45 31 41 s 174 56 88 e 1204 m southern margin of the chatham rise shows important fluctuations in species composition from glacial to interglacial over the last 140 000 yr reconstruction of winter and summer ssts reveals much lower temperature than present by 6 to 10 c during marine oxygen isotope stages 6 4 and 2 and higher temperature by 2 3 c during substage 5e copyright 2001 john wiley sons ltd journal of quaternary science

a radiolarian based palaeoclimate history of core y9 northeast of campbell plateau new zealand for the last 160 kyr abstract sea surface temperatures ssts based on radiolarian assemblage changes are estimated for the last 160 kyr from a sediment core y9 recovered from pukaki saddle northeast of campbell plateau site y9 lies beneath subantarctic surface water saw immediately to the north of the subantarctic front saf which in this region is bathymetrically constrained by the edges of campbell plateau and defines the northern boundary of the antarctic circumpolar current acc radiolarian assemblages are characterised by an exceptionally high abundance of the antarctic to subantarctic species antarctissa spp up to 68 especially during glacial intervals sst estimates are derived using factor analysis and the modern analog technique both methods capture the glacial interglacial g i pattern the sst reconstructions show the changing relative influence of distinct water masses during the past g i cycle with major temperature variations of the order of 7 9 c at glacial terminations glacials marine isotope stages mis 6 and 2 are associated with particularly cool ssts that are indicative of a more vigorous saf acc and an enhancement of the inflow through pukaki saddle and or frequent development of cold core eddies at the saf by contrast the influence of warmer waters and relaxation of the acc during interglacials can be inferred from temperatures slightly warmer e g mid holocene and or comparable to present day e g mis 5e during these intervals relatively warmer temperatures most likely indicate a higher warm core eddy activity due to a strengthened subtropical front and or a weakened inflow of cool water through pukaki saddle and or an increased stratification in the campbell plateau region furthermore the sst record is characterised by an abrupt warming at ca 10 kyr i e termination i the occurrence of a reversal at termination i and a warming event at the end of mis 4 coinciding with the a4 event in the byrd ice core these characteristics together with the pronounced g i cycle shown by the sst estimates suggest that site y9 is influenced by major oceanographic changes in the sw pacific and responds to thermal changes at high southern latitudes

late quaternary palaeoenvironmental change in the australian drylands in this paper we synthesise existing palaeoenvironmental data from the arid and semi arid interior of the australian continent for the period 40 0 ka moisture is the predominant variable controlli

sea surface temperature estimates for the tropical western pacific during the last glaciation and their implications for the pacific warm pool twenty deep sea sediment cores from the western pacific between 30 n and 30 s provide evidence of sea surface temperature sst changes throughout the tropics and subtropics glacial ssts were estimated using the modern analog technique mat applied to planktonic foraminifers and planktonic foraminiferal 18o changes we used 18o to identify the last glacial maximum the mat method differs from the traditional transfer function approach in that it utilizes a global coretop database and estimates paleotemperature by finding analogs from the modern coretop samples in addition the mat approach appears to be less susceptible than the transfer function technique to biases introduced by carbonate dissolution our results indicate that tropical ssts differed by less than 2 c from present away from the tropics 30 n and 30 s ssts were at least 3 c cooler our results differ from those of previous studies in the western pacific by using a set of well preserved high sedimentation rate cores from shallow regions the results of this study clearly indicate that a western pacific warm pool existed during the last glacial maximum lgm providing a heat and moisture source for a walker circulation cell similar to that of today we propose that a steeper lapse rate existed during the last glacial maximum and that this can explain at least part of the discrepancy between marine and terrestrial temperature estimates adjacent to new guinea for the lgm

low latitude glacial cooling in the southern hemisphere from amino acid racemization in emu eggshells the record of natural climate variability over glacial interglacial timescales provides a framework from which a better mechanistic understanding of the climate system may be derived but this approach is limited by the number and distribution of well dated and reliable palaeoenvironmental archives particularly vexing is the conflicting evidence for low latitude cooling during the last glacial maximum and the apparent synchrony in glacial activity between the hemispheres despite out of phase insolation forcing1 4 here we utilize the temperature dependent amino acid racemization reaction in radiocarbon dated emu eggshell fragments from the continental interior of australia to reconstruct low altitude subtropical temperatures for the past 45 kyr racemization rate changes indicate that millennial scale average air temperatures were at least 9 c lower between 45 and 16 kyr bp than since 16 kyr bp a temperature change of this magnitude coupled with other low latitude palaeotemperature records that indicate substantial cooling3 4 must reflect global processes which we speculate involved glacial age reduction in atmospheric water vapour content

a coupled climate model simulation of the last glacial maximum part 2 approach to equilibrium the climate of the last glacial maximum lgm is simulated with a coupled climate model the simulated climate undergoes a rapid adjustment during the first several decades after imposition of lgm boundary conditions as described in part 1 and then evolves toward equilibrium over 900 model years the climate simulated by the coupled model at this period is compared with observationally based lgm reconstructions and with lgm results obtained with an atmosphere mixed layer slab ocean version of the model in order to investigate the role of ocean dynamics in the lgm climate global mean surface air temperature and sea surface temperature sst decrease by about 10 c and 5 6 c in the coupled model which includes ocean dynamics compared to decreases of 6 3 and 3 8 c in slab ocean case the coupled model simulates a cooling of about 6 5 c over the tropics which is larger than that of the climap reconstruction 1 7 c and larger than that of the slab ocean simulation 3 3 c but which is in reasonable agreement with some recent proxy estimates the ocean dynamics of the coupled model captures features found in the climap reconstructions such as a relative maximum of ocean cooling over the tropical pacific associated with a mean la nina like response and lead to a more realistic sst pattern than in the slab model case the reduction in global mean precipitation simulated in the coupled model is larger 15 than that simulated with the slab ocean model 10 in conjunction with the enhanced cooling some regions such as the usa and the mediterranean region experience increased precipitation in accord with proxy paleoclimate evidence the overall much drier climate over the ocean leads to higher sea surface salinity sss in most ocean basins except for the north atlantic where sss is considerably lower due to an increase in the supply of fresh water from the mississippi and amazon rivers and presumably a decrease in salt transport by the weakened north atlantic overturning circulation the north atlantic overturning stream function weakens to less than half of the control run value the overturning is limited to a shallower depth less than 1000 m and its outflow is confined to the northern hemisphere in the southern ocean convection is much stronger than in the control run leading to a stronger overturning stream function associated with enhanced antarctic bottom water formation as a result southern ocean water masses fill the entire deep ocean the antarctic circumpolar current acc transport through the drake passage increases by about 25 the acc transport despite weaker zonal winds is enhanced due to changes in bottom pressure torque the weakening of the overturning circulation in the north atlantic and the accompanying 30 decrease in the poleward ocean heat transport contrasts with the strengthening of the overturning circulation in the southern ocean and a 40 increase in heat transport as a result sea ice coverage and thickness are affected in opposite senses in the two hemispheres the lgm climate simulated by the coupled model is in reasonable agreement with paleoclimate proxy evidence the dynamical response of the ocean in the coupled model plays an important role in determining the simulated and undoubtedly the actual lgm climate

numerically simulating alpine landscapes the geomorphologic consequences of incorporating glacial erosion in surface process models abstract a numerical model that simulates the evolution of glaciated mountain landscapes is presented by employing a popular sliding based glacial erosion model many common glacial landforms are created the numerical model builds on earlier work as it is fully two dimensional and employs the first order forcing on mountain evolution these forcings include tectonic uplift isostasy hillslope processes fluvial processes and glacial processes a climate dependent model of ice dynamics is employed to determine ice coverage and ice flux two simulations are presented one with generic model parameters and a second with parameters that correspond to conditions in the southern alps of new zealand landforms that are produced by the model include climate climate dependent elevation lowering similar to what might be expected by a glacial buzz saw valley overdeepening terminal moraines and valley retreat the model also predicts that current rates of sedimentation are higher than the long term average and that several tens of thousands of years are required for the landscape to adjust to a change in the dominant erosional forcing therefore glaciated orogens are unlikely to achieve topographic steady state over milankovitch timescales

response of surface water masses and circulation to late quaternary climate change east of new zealand a series of cores from east of new zealand have been examined to determine the paleoceanographic history of the late quaternary in the sw pacific using planktonic foraminiferal data distinct shifts of species can be seen between glacial and interglacial times especially south of chatham rise east of south island foraminiferal fragmentation ratios and benthic planktonic foraminiferal ratios both show increased dissolution during glacials especially isotope stage 2 to the south of chatham rise the present day subtropical convergence appears to be tied to the chatham rise at 44 s but during glacial times this rise separated cold water to the south from much warmer water to the north with an associated strong thermal gradient across the rise we estimate that this gradient could have presented as much as an 8 c temperature change across 4 of latitude during the maximum of the last ice age there is only weak evidence of the younger dryas cool event but there is a clear climatic optimum between 8 and 6 4 ka with temperatures 1 2 c higher than the present day the marine changes compare well with vegetational changes on both south and north island

a fossil coral perspective on western tropical pacific climate 350 ka 1 the nature of tropical climate variability 350 ka is addressed using 18o and sr ca records from a modern and a fossil coral from vanuatu southwestern tropical pacific ocean modern el nino events at vanuatu produce positive coral 18o and sr ca anomalies similar anomalies observed in the fossil coral records suggest that el nino was operative 350 kyr ago seasonal variations in coral sr ca a sea surface temperature sst proxy have the same amplitude in both corals whereas seasonal 18o variations are smaller in the fossil coral than in the modern coral this is consistent with displacement of the south pacific convergence zone toward the southwest during the boreal summer 350 ka mathematical modeling results preclude warmer sst and higher sss at vanuatu during this time but permit the surface ocean to be 2 c cooler and 0 2 psu fresher than today assessing the potential of variations in late quaternary seawater sr ca remains the largest obstacle to accurately reconstructing tropical sst using pristine fossil corals

carbon isotope evidence for changes in antarctic intermediate water circulation and ocean ventilation in the southwest pacific during the last deglaciation 1 deep sea sediment core fr1 97 gc 12 is located 990 mbsl in the northern tasman sea southwest pacific where antarctic intermediate water aaiw presently impinges the continental slope of the southern great barrier reef analysis of carbon 13c and oxygen 18o isotope ratios on a suite of planktonic and benthic foraminifera reveals rapid changes in surface and intermediate water circulation over the last 30 kyr during the last glacial maximum there was a large 13c offset 1 1 between the surface dwelling planktonic foraminifera and benthic species living within the aaiw in contrast during the last deglaciation termination 1 the 13cplanktonic benthic offset reduced to 0 4 prior to an intermediate offset 0 7 during the holocene we suggest that variations in the dominance and direction of aaiw circulation in the tasman sea and increased oceanic ventilation can account for the rapid change in the water column 13cplanktonic benthic offset during the glacial interglacial transition our results support the hypothesis that intermediate water plays an important role in propagating climatic changes from the polar regions to the tropics in this case climatic variations in the southern hemisphere may have led to the rapid ventilation of deep water and aaiw during termination 1 which contributed to the postglacial rise in atmospheric co2

benthic foraminifera and the late quaternary last 150 ka paleoceanographic and sedimentary history of the bounty trough east of new zealand abstract the bounty trough east of new zealand lies along the southeastern edge of the present day subtropical front stf and is a major conduit via the bounty channel for terrigenous sediment supply from the uplifted southern alps to the abyssal bounty fan census data on 65 benthic foraminiferal faunas 63 m from upper bathyal odp 1119 lower bathyal dsdp 594 and abyssal odp 1122 sequences test and refine existing models for the paleoceanographic and sedimentary history of the trough through the last 150 ka marine isotope stages mis 6 1 cluster analysis allows recognition of six species groups whose distribution patterns coincide with bathymetry the climate cycles and displaced turbidite beds detrended canonical correspondence analysis and comparisons with modern faunal patterns suggest that the groups are most strongly influenced by food supply organic carbon flux and to a lesser extent by bottom water oxygen and factors relating to sediment type major faunal changes at upper bathyal depths 1119 probably resulted from cycles of counter intuitive seaward landward migrations of the southland front sf north south sector of the stf benthic foraminiferal changes suggest that lower nutrient cool subantarctic surface water saw was overhead in warm intervals and higher nutrient bearing warm neritic subtropical surface water stw was overhead in cold intervals at lower bathyal depths 594 foraminiferal changes indicate increased glacial productivity and lowered bottom oxygen attributed to increased upwelling and inflow of cold nutrient rich antarctic intermediate water aaiw and shallowing of the oxygen minimum zone upper circum polar deep water cpdw the observed cyclical benthic foraminiferal changes are not a result of associations migrating up and down the slope as glacial faunas dominated by globocassidulina canalisuturata and eilohedra levicula at upper and lower bathyal depths respectively are markedly different from those currently living in the bounty trough on the abyssal bounty fan 1122 faunal changes correlate most strongly with grain size and are attributed to varying amounts of mixing of displaced and in situ faunas most of the displaced foraminifera in turbiditic sand beds are sourced from mid outer shelf depths at the head of the bounty channel turbidity currents were more prevalent during but not restricted to glacial intervals

the southern hemisphere westerlies in the australasian sector over the last glacial cycle a synthesis abstract the southern hemisphere westerlies in the southwest pacific are known to have waxed and waned numerous times during the last two glacial cycles though even semi continuous histories of the westerlies extend back no more than about 20 000 years we have good evidence for at least three scales of events a westerly maximum occurs at the last glacial maximum there is less conclusive evidence for another westerly maximum in the late holocene and for a minimum at ca 11 ka it is too early to ascribe even a cycle to these data but there are grounds to suggest that milankovitch precessional forcing may underlie the observed pattern there is also a quasi 2600 year cycle present in antarctic ice cores that appears to correlate to variation in westerly flow there is strong centennial scale variability in historical times the little ice age lia ca 1400 1850 was associated with a poleward shift in the circumpolar trough in the southern ocean strengthened westerly circulation over tasmania and a strengthening of southwesterly circulation and neoglaciation in southern new zealand while the preceding period 800 1400 ad was less certainly marked by reduced westerly flow from modern records we know that decadal and inter annual variability is important e g pacific decadal oscillation high latitude mode also known as the antarctic oscillation el nino southern oscillation only a minority of the proxies examined can identify changes on these temporal scales but data from tree rings ice cores and laminated lake sediments do indicate systematic changes in these phenomena through time rossby wave patterns are shown to play a critical role in long duration events as well as at the synoptic scale we conclude that westerly circulation is as strong now as at any time in the last glacial cycle in addition changes in latitudinal boundaries in the westerlies may be nearly as large in inter annual zonal shifts ca 2 maximum as in glaciation interglaciation movements ca 3 4 there is however reasonable evidence of strengthening weakening across much of the westerly belt at westerly maxima minima such as the lia early holocene

speleothem master chronologies combined holocene 18o and 13c records from the north island of new zealand and their palaeoenvironmental interpretation the stable isotope records of four stalagmites dated by 19 tims uranium series ages are combined to produce master chronologies for delta 18 o and delta 13 c the delta 18 o records display good overall coherence but considerable variation in detail variability in the delta 13 c records is greater but general trends can still be discerned this implies that too fine an interpretation of the structure of individual isotopic records can be unreliable speleothem delta 18 o values are demonstrated to show a positive relationship with temperature by comparing trends with other proxy records but also to respond negatively to rainfall amount speleothem delta 13 c is considered to be most influenced by rainfall the postglacial thermal optimum occur red around 10 8 ka bp which is similar in timing to antarctica but up to 2000 years earlier than most northern hemisphere sites increasingly negative delta 18 o values after 7 5 ka bp indicate that temperatures declined to a late mid holocene minimum centred around 3 ka bp but more positive values followed to mark a warm peak about 750 years ago which coincided with the mediaeval warm period of europe low 5110 values at 325 years bp suggest cooling coincident with the little ice age a marked feature of the delta 13 c record is an asymmetric periodicity averaging c 2250 years and amplitude of c 1 9parts per thousand it is concluded that this is mainly driven by waterbalance variations with negative swings representing particularly wet intervals the 5110 record shows a higher frequency cyclicity with a period of c 500 years and an amplitude of c 0 25 parts per thousand this is most likely to be temperature driven but some swings may have been amplified by precipitation

a late quaternary record of vegetation and climate change from hazards lagoon eastern tasmania a late quaternary pollen and charcoal record from hazards lagoon on the east coast of tasmania provides a continuous record of vegetation and climate change the pollen record shows an epacridaceae and poaceae dominated grassland community replaced dry sclerophyll forest during the last glacial maximum lgm 22 18 cal ka bp eucalyptus and casuarinaceae increased from the beginning of the deglacial period 18 12 cal ka bp indicating early warming on the east coast of tasmania abundant myriophyllum and sedimentary characteristics indicate hazards lagoon was a permanent source of water throughout the lgm and until 16 cal ka bp suggesting either increased precipitation and or decreased evaporation rates a positive moisture balance throughout the lgm contrasts with records from the west coast of tasmania and parts of mainland australia fire was suppressed at the site until 14 cal ka bp corresponding with reduced woody vegetation and a positive moisture balance dry sclerophyll forest established during the deglacial period remaining stable throughout the holocene a coastal vegetation community developed in response to sea level rise characterised by abundant eucalyptus pollen and increasing values of casuarinaceae by the mid holocene the hazards lagoon pollen record is typical of a tasmanian coastal site dominated by casuarinaceae this research highlights the need for spatially diverse studies throughout the southern hemisphere to identify drivers of environmental change during the late quaternary

sermeq model produces a realistic upper bound on calving retreat for 155 greenland outlet glaciers the rate of land ice loss due to iceberg calving is a key source of variability among model projections of 21st century sea level rise it is especially challenging to account for mass loss due to

terrestrial conditions at the last glacial maximum and climap sea surface temperature estimates are they consistent climap 1981 seasonal reconstruction of the earth s surface at the last glacial maximum geological society of america map and chart series mc 36 boundary conditions were used as inputs to the giss general circulation model and the last glacial maximum lgm climate was simulated for six model years the simulation was compared with snow line depression and pollen inferred temperature data at low latitudes specifically for hawaii colombia east africa and new guinea the model does not produced as much cooling at low latitudes as is implied by the terrestrial evidence an alternative experiment in which the climap sea surface temperatures were uniformly lowered by 2 c produces a better fit to the land data although in hawaii model temperatures are still too warm the relatively warm climap tropical sea surface temperatures also provide for only a slight decrease in the hydrologic cycle in the model in contrast to both evidence of lgm tropical aridity and the results of the experiment with colder ocean temperatures with the climap sea surface temperatures the lgm global annual mean surface air temperature is 3 6 c colder than at present if the ocean temperatures were allowed to cool in conformity with the model s radiation balance the lgm simulation would be 5 6 c colder than today and in better agreement with the tropical land evidence

reconstruction of sea surface temperatures from assemblages of planktonic foraminifera multi technique approach based on geographically constrained calibration data sets and its application to glacial atlantic and pacific oceans abstract we present a conceptual framework for a new approach to environmental calibration of planktonic foraminifer census counts this approach is based on simultaneous application of a variety of transfer function techniques which are trained on geographically constrained calibration data sets it serves to minimise bias associated with the presence of cryptic species of planktonic foraminifera and provides an objective tool for assessing reliability of environmental estimates in fossil samples allowing identification of adverse effects of no analog faunas and technique specific bias we have compiled new calibration data sets for the north n 862 and south n 321 atlantic and the pacific ocean n 1111 we show evidence that these data sets offer adequate coverage of the sea surface temperature sst and faunal variation range and that they are not affected by the presence of pre holocene samples and or calcite dissolution we have applied four transfer function techniques including artificial neural networks revised analog method and simmax with and without distance weighting on faunal counts in a last glacial maximum lgm data set for the atlantic ocean 748 samples in 167 cores based on the glamap 2000 compilation and a new data set for the pacific ocean 265 samples in 82 cores and show that three of these techniques provide adequate degree of independence for the advantage of a multi technique approach to be realised the application of our new approach to the glacial pacific lends support to the contraction and perhaps even a cooling of the western pacific warm pool and a substantial 3 c cooling of the eastern equatorial pacific and the eastern boundary currents our results do not provide conclusive evidence for lgm warming anywhere in the pacific the atlantic reconstruction shows a number of robust patterns including substantial cooling of eastern boundary currents with considerable advection of subpolar waters into the benguela current a cooling of the equatorial atlantic by 5 c and steep sst gradients in the mid latitude north atlantic the transfer function techniques generally agree that subtropical gyre areas in both hemispheres did not change significantly since the lgm although the ann technique produced glacial sst in the southern gyre 1 2 c warmer than today we have revisited the issue of sea ice occurrence in the nordic seas and using the distribution of subpolar species of planktonic foraminifera in glacial samples we conclude that the norwegian sea must have been ice free during the summer

the sedimentary record of palaeoenvironments and sea level change in the gulf of carpentaria australia through the last glacial cycle abstract environmental evolution of the gulf of carpentaria region the world s largest tropical epicontinental seaway through the last glacial cycle has been determined from a series of six sediment cores these cores form the focus of a multi disciplinary study to elucidate sea level climate and environmental change in the region the sedimentary record reveals a series of facies including open shallow marine marginal marine estuarine lacustrine and subaerial exposure throughout the extent of the basin during this period the partial or complete closure of the central basin from marine waters results from sea level falling below the height of one or both of the sills that border the gulf the arafura sill to the west 53 m below present sea level bpsl and torres strait to the east 12 m bpsl the extent and timing of these closures and restriction of the shallow waterbody within are intrinsic to local ocean circulation available latent heat transport and the movement of people and animals between australia and new guinea whilst the occurrence of the palaeo lake carpentaria has previously been identified this study expands on the hydrological conditions of the lacustrine phases and extends the record through the last interglacial detailing the previous sea level highstand mis 5 5 and subsequent retreat when sea levels were low during the mis 6 glacial period the gulf was largely subaerially exposed and traversed by meandering rivers the mis 5 transgression 130 ka bp led to marine then alternating marine estuarine conditions through to mis 4 70 ka bp when a protracted lacustrine phase of varying salinity and depth area and including periods of near desiccation persisted until about 12 2 cal ka bp the lake expanded to near maximum size 190 000 km 2 following the intensification restoration of the australian monsoon at 14 ka bp this lake full phase was short lived as by 12 2 cal ka bp marine waters were entering the basin coincident with the progressive sea level rise fully marine conditions were restored by about 10 5 cal ka bp by westward connection to the arafura sea indian ocean whereas connections to the pacific ocean coral sea did not occur until about 8 cal ka bp

the timing and cause of glacial advances in the southern mid latitudes during the last glacial cycle based on a synthesis of exposure ages from patagonia and new zealand abstract glacier advances in the southern mid latitudes during the last glacial cycle ca 110 10 ka were controlled by changes in temperature and precipitation linked to several important ocean climate systems as such the timing of glacial advance and retreat can yield important insights into the mechanisms of southern hemisphere climate change this is particularly important given that several recent studies have demonstrated significant glacial advances prior to the global last glacial maximum glgm in patagonia and new zealand the cause of which are uncertain the recent increase in chronological studies in these regions offers the opportunity to compare regional trends in glacial activity here we compile the first consistent 10be exposure dating chronologies for patagonia and new zealand to highlight the broad pattern of mid latitude glacial activity over the last glacial cycle our results show that advances or still stands culminated at 26 27 ka 18 19 ka and 13 14 ka in both patagonia and new zealand and were broadly synchronous but with an offset between regions of up to 900 years that cannot be explained by age calculation or physically plausible erosion differences furthermore there is evidence in both regions for glacial advances culminating from at least 45 ka during the latter half of marine isotope stage mis 3 glacial activity prior to the glgm differed from the large northern hemisphere ice sheets likely due to favourable southern hemisphere conditions during late mis 3 summer insolation reached a minimum seasonality was reduced winter duration was increasing and sea ice had expanded significantly inducing stratification of the ocean and triggering northward migration of oceanic fronts and the southern westerly winds glacial advances in patagonia and new zealand during the glgm were probably primed by underlying orbital parameters however the precise timing is likely to have been intrinsically linked to migration of the coupled ocean atmosphere system which may account for the small offset between patagonia and new zealand due to differences in oceanic frontal migration during deglaciation advances or still stands occurred in both regions during the southern antarctic cold reversal ca 14 5 12 9 ka rather than the northern younger dryas ca 12 9 11 7 ka our findings suggest that major rearrangements of the southern hemisphere climate system occurred at various times during the last glacial cycle with associated impacts on the position and intensity of the southern westerly winds and oceanic fronts as well as wind driven upwelling and degassing of the deep southern ocean thus reconstructing the timing of glacial advance retreat using our compilation is a powerful way to understand the mechanisms of past interhemispheric climate change

oceanic surface conditions recorded on the sea floor of the southwest pacific ocean through the distribution of foraminifers and biogenic silica over 180 surface sediment samples from the southwest pacific ocean were investigated for their planktonic foraminiferal 149 m opaline and terrigenous sediment content with the aim to determine the oceanic conditions at the sea surface above the sampling sites high concentrations of biogenic opal are related to high productivity levels recognised in tropical surface waters the abundance of this biogenic opal found within the sediments on the ocean floor shows a slight decrease as one approaches the australian landmass and also poleward from the equatorial belt the distribution of major species of planktonic formainifers reflects different surface water masses q mode factor analysis of planktonic foraminiferal percentage data from 63 core tops permits identification of several characteristic formainiferal assemblages for the southwest pacific ocean four factors explain up to 95 5 of the total variance factor 1 66 is dominated by the tropical subtropical species globigerinoides sacculifer and globigerinoides ruber the transitional to subpolar species globorotalia inflata is important in factor 2 12 the temperate cool factor 3 13 is characterised by turborotalia quinqueloba and globigerinita glutinata factor 4 which explains 3 of the total variance and which is represented by several species is assigned to the high productive equatorial and coastal waters off the australian continental margin palaeoecological equations permitting an estimate of sea surface temperatures and salinities are presented the correlation coefficients between modern data adapted from literature and estimated by transfer function fp 4 transfer function for planktonic formainifers are 0 95 for temperature and 0 77 for salinity

estimates of sea surface temperature in the coral sea at the last glacial maximum the climap 1981 reconstruction of the coral sea found relatively little cooling 2 c in the low latitudes 10 s but a warming off australia at about 25 s the small low latitude changes are of interest because terrestrial pollen and snowline data from the new guinea highlands imply that surface temperatures may have been 6 to 9 c colder at the last glacial maximum lgm the purpose of this paper is to evaluate these conclusions on the basis of additional core sites new oxygen isotope stratigraphy and new sea surface temperature sst estimates using the modern analog technique mat in the northern coral sea planktonic foraminifer assemblages consist of tropical subtropical species that show little change over the past 20 kyr quantitative estimates of sst using the modern analog technique mat confirm the climap 1981 conclusion that little or no temperature change occurred in this tropical region at the lgm thus reinforcing the conflict with terrestrial evidence in the southern region 25 s two cores indicate that foraminifer faunas became more subtropical at the lgm the mat estimates for the lgm are 3 to 4 c colder than modern producing a steeper thermal gradient in the southern coral sea these data remove the warm sst anomaly along the eastern coast of australia and indicate that during the lgm cool high latitude waters were displaced northward along the coast of australia into the southern coral sea

planktonic foraminiferal flux seasonality in subantarctic sediment traps a test for paleoclimate reconstructions sediment trap moorings deployed during 1997 and 1998 in the subantarctic to polar frontal regions of the southern ocean reveal distinct seasonality in foraminiferal flux foraminiferal assemblages vary between each site yet major species exhibit very similar patterns of seasonal succession which can be associated with changes in mixed layer depth enhanced foraminiferal productivity is also associated with periods of high biogenic silica and particulate organic carbon flux on a broader scale foraminiferal assemblages are strongly delineated by temperature temperature estimates derived from the assemblages using the modern analog technique mat are mostly within 2 5 c of the satellite advanced very high resolution radiometer temperatures observed during the deployment period this indicates that core top sediments included in the mat database do reflect modern observed conditions at the sea surface providing a robust technique for estimating past temperature change from foraminiferal assemblages in southern ocean environments

comparing simulated glacial climate and paleodata a reexamination glacial sea surface temperatures ssts simulated by an atmosphere mixed layer ocean model are compared with those reconstructed by the climate long range investigation mapping and prediction climap project using planktonic microfossils two methods of comparison are employed the first is global and uses the subjectively analyzed i e hand contoured then digitized data set published by climap the second is restricted to only those discrete locations where the climap sediment cores were taken both methods indicate that many aspects of the reconstructed glacial sst changes are simulated reasonably well by the model although there are areas of disagreement the extent of the disagreement appears smaller when the ssts are sampled at discrete locations because the largest discrepancies occur in the subtropical pacific where data are sparse when examined separately for each ocean the magnitude of the disagreement in low latitudes roughly corresponds to the magnitude of the uncertainties in sst estimation using planktonic microfossils being largest in the pacific and smallest in the atlantic because the largest discrepancies occur where uncertainties in estimation are large no clear determination of whether the climate model exaggerates or underestimates low latitude climate sensitivity appears possible nonetheless sampling at discrete locations may be the best procedure for evaluating climate model performance because errors associated with extending analyses to data void areas can be avoided and uncertainties associated with inadequate spatial sampling made more evident

planktic foraminiferal and sea surface temperature record during the last 1 myr across the subtropical front southwest pacific planktic foraminiferal faunas and modern analogue technique estimates of sea surface temperature sst for the last 1 million years myr are compared between core sites to the north odp 1125 178 faunas and south dsdp 594 374 faunas of the present location of the subtropical front stf east of new zealand faunas beneath cool subtropical water stw north of the stf are dominated by dextral neogloboquadrina pachyderma globorotalia inflata and globigerina bulloides whereas faunas to the south are strongly dominated by sinistral n pachyderma 80 95 in glacials with increased g bulloides 20 50 and dextral n pachyderma 15 50 in interglacials beneath subantarctic water or saw canonical correspondence analysis indicates that at both sites sst and related factors were the most important environmental influences on faunal composition greater climate related faunal fluctuations occur in the south significant faunal changes occur through time at both sites particularly towards the end of the mid pleistocene climate transition mis18 15 e g decline of globorotalia crassula in stw disappearance of globorotalia puncticulata in saw and during mis8 5 interglacial sst estimates in the north are similar to the present day throughout the last 1 myr to the south interglacial ssts are more variable with peaks 4 7 c cooler than present through much of the early and middle pleistocene but in mis11 mis5 5 and early mis1 peaks are estimated to have been 2 4 c warmer than present these high temperatures are attributed to southward spread of the stf across the submarine chatham rise along which the stf appears to have been dynamically positioned throughout most of the last 1 myr for much of the last 1 myr glacial sst estimates in the north were only 1 2 c cooler than the present interglacial except in mis16 mis8 mis6 and mis4 2 when estimates are 4 7 c cooler these cooler temperatures are attributed to jetting of saw through the mernoo saddle across the chatham rise and or waning of the stw current to the south glacial sst estimates were consistently 10 11 c cooler than present similar to temperatures and faunas currently found in the vicinity of the polar front one interpretation is that these cold temperatures reflect thermocline changes and increased circumpolar surface water spinning off the subantarctic front as an enhanced bounty gyre along the south side of the chatham rise for most of the last 1 myr the temperature gradient across the stf has been considerably greater than the present 4 c during glacial episodes the stf in this region did not migrate northwards but instead there was an intensification of the temperature gradient across it interglacials 4 11 c glacials 8 14 c

comparison of organic uk 37 texh86 ldi and faunal proxies foraminiferal assemblages for reconstruction of late quaternary sea surface temperature variability from offshore southeastern australia several proxies have been developed to reconstruct past sea surface temperature sst but different proxies may reflect temperatures of different seasons and each proxy is characterized by certain uncertainties therefore a multiproxy approach is preferred to precisely reconstruct sst here we reconstruct sst of the ocean offshore southeastern australia murray canyons area for the last 135 ka using three independent organic proxies texh86 based on glycerol dialkyl glycerol tetraethers gdgts uk 37 based on alkenones and ldi based on long chain diols in addition to foraminiferal faunal assemblages the organic proxy records show similar trends with the highest temperature 21 c for uk 37 and texh86 and 25 c for ldi during the last interglacial and lowest temperature 8 c for texh86 10 c for uk 37 and 12 c for ldi during the last glacial maximum however the differences in absolute sst estimates obtained by the organic proxies varied over time with differences of up to 9 c between ldi and texh86 the seasonal sst reconstructions based on the modern analogue of foraminiferal assemblages also show similar trends as the organic proxies with highest temperatures during the last interglacial 23 c for the warmest month sst 20 c for mean annual and 18 c for the coolest month and lowest temperature during the last glacial maximum 14 c for the warmest month 11 c for mean annual and 9 c for the coolest month down core comparison between the reconstructed ssts of the organic and inorganic proxies shows that ldi inferred temperatures compare well with the temperature of the warmest month texh86 with the temperature of the coolest month and uk 37 with mean annual temperature an increase in texh86 sst estimates relative to those of other proxies during deglaciations and interglacials suggests that either winter temperatures rapidly warmed possibly due to an invigoration of the leeuwin current over the core site or there was a change in the growth season of the thaumarchaeota the source organism of gdgts our study shows the benefits of a multiproxy approach in the interpretation of sst proxies leading to a more robust knowledge of past ocean temperature changes

australian dust deposits modern processes and the quaternary record abstract dust raising and transport are common and important processes in australia today the aridity of the australian continent and high climatic variability result in widespread dust raising in the arid and semi arid areas and transport to the humid margins and surrounding oceans the supply of erodible particles appears to be the greatest limitation on total flux of transported dust dust raising is greatest in the lake eyre basin including the simpson desert and murray darling basin where internal drainage renews supplies of fine particles to the arid zone in the west and northwest dust entrainment is low despite considerable aridity the marine record of dust flux shows at least a threefold increase in dust flux compared with the holocene in the last glacial maximum in both tropical and temperate australia driven by weakened australian monsoon rains and drier westerly circulation respectively despite the widespread confirmation of aeolian dust deposits in southeastern and southwestern australia dated or quantified records are extremely rare the dominant model of australian dust deposits the clay rich parna is shown to be poorly substantiated while modern and ancient dust deposits examined in detail are shown to bear a strong similarity to conventional definitions of loess