holocene reef growth in torres strait the platform and fringing reefs of torres strait are morphologically similar to reefs of the northern great barrier reef to the south except that several are elongated in the direction of the strong tidal currents between the coral sea and the gulf of carpentaria surface and subsurface investigations and radiocarbon dating on yam warraber and hammond islands reveal that the initiation and mode of holocene reef growth reflect antecedent topography and sea level history on the granitic yam island fringing reefs have established in some places over a pleistocene limestone at about 6 m depth around 7000 years bp emergent holocene microatolls of porites sp indicate that the reefs have prograded seawards while sea level has fallen gradually from at least 0 8 m above present about 5800 years bp on the warraber island reef platform drilling near the centre indicated a pleistocene limestone foundation at a depth of about 6 m over which reefs established around 6700 years bp reef growth lagged behind that on yam island microatolls on the mature reef flat indicate that the reef reached sea level around 5300 years bp when the sea was around 0 8 1 0 m above present on the reef flat on the western side of hammond island bedrock was encountered at 7 8 m depth overlain by terrigenous mud a progradational reef sequence of only 1 2 m thickness has built seaward over these muds as sea level has fallen over the past 5800 years reef flat progradation on these reefs is interpreted to have occurred by a series of stepwise buildouts marked by lines of microatolls parallel to the reef crest marking individual coalescing coral heads detrital infill has occurred between these this pattern of reef progradation is consistent with the radiocarbon dating results from these reefs and with seismic investigations on the torres reefs

the fujita ziegler model a new semi quantitative technique for estimating paleoclimate from paleogeographic maps abstract the fujita ziegler model combines approaches developed by t t fujita and a m ziegler of the university of chicago to produce semi quantitative retrodictions of paleoclimates based on paleogeographic maps that include the sizes and positions of land and sea areas and the positions and extents of upland areas based on such paleogeographic maps the fujita model extrapolates past values of surface air pressure from present day relationships among air pressure land area latitude and season zonal mean air pressure for each latitude and season is hypothesized to depend on the amount of land area at that latitude and deviations from this mean over major bodies of land or water are hypothesized to depend on the area of the relevant body at that latitude fujita diagrams both illustrate these hypottheses and permit application of the model to paleogeographic maps surface air pressure maps based on these diagrams can be used to qualitatively retrodict seasonal windflow patterns and ocean currents tests of the fujita model on the recent geography suggest that most major air pressure cells are positioned accurately and that the values at the centers of cells are within 2 3 mb of measured values at low and middle latitudes and within 5 mb at the poles because the fujita model extrapolates from a partly glaciated world its retrodictions for ice free times are suspect particularly near the poles the ziegler model infers the areal and seasonal distribution of precipitation from reconstructed patterns of winds and ocean currents on paleogeographic maps retrodictions are based on 1 mechanisms that lift air including global patterns of atmospheric circulation intertropical convergence zone regional storm systems extratropical cyclones and relatively local lifting mechanisms orographic effects land sea breezes and summer convective thunderstorms 2 sources of moist air i e bodies of warm water upwind and 3 mechanisms that interfere with convection e g upwelling zones and trade wind inversions tests of the ziegler model on the recent geography accurately retrodicted seasonal precipitation at low and middle latitudes but did less well near the poles comparison with maps of the seasonality of precipitation in the recent shows that the model accurately retrodicted most ever dry and ever dry regions results emphasize the importance of accurately retrodicting the effects of orography moisture source and upwelling zones on precipitation

milankovitch forcing of fluctuations in the level of tropical lakes from 18 to 0 kyr bp an atmospheric general circulation model has been used to simulate the climates of january and july at 3 000 yr intervals from 15 kyr bp onwards the model simulates a strengthened monsoon circulation and increased precipitation in the northern hemisphere tropics culminating at 9 6 kyr bp the computed hydrological budgets were used to estimate the area of closed lakes between 8 9 and 26 6 n giving with minor exceptions results in good agreement with geological evidence

post glacial sea level rise from a coral record at huon peninsula papua new guinea dating of coral reef terraces can provide a record of changes in sea level which should be pronounced during the transition between glacial and interglacial periods cores drilled from coral reefs at barbados in the equatorial west atlantic1have revealed the sea level changes that occurred during the younger dry as event at the end of the last glacial maximum 11 000 yr bp it has not been known however whether pacific coral reefs can grow at a rate sufficient to keep up with the rise in sea level during such a transition here we report results obtained from a 52 m drill core from the post glacial reef at huon peninsula papua new guinea spanning the interval from 7 000 to 11 000 14c yr bp which show that coral growth kept pace while the relative sea level rose by 50m although the tectonic environment is very different from that at barbados the two records compare well when corrections are made for local tectonic uplift showing that sea level rise was similar at both locations the rate of rise was greatest between 9 000 and 10 00014c yr bp corresponding to the time of the younger dryas

cyclic paleo salinity changes inferred from benthic foraminiferal assemblages in the upper burdigalian lower miocene korneuburg basin austria abstract the late burdigalian karpatian korneuburg basin gives an excellent insight into the continuous modification of its paleo environments and paleo ecology and therefore into its dynamics over geological time scales the investigated outcrops provided a unique opportunity to study the change of foraminiferal assemblages in an early miocene estuarine marine system as a response to climate precipitation oscillations to this end we studied foraminiferal assemblages ostracods provided additional information paleo salinities were estimated by applying a transfer equation using modern frequency distributions of indicative foraminiferal taxa this technique is used here for the first time to reconstruct salinity in the past and may facilitate further studies in shallow water paleo environments elsewhere on the basis of the recorded benthic foraminiferal assemblages their modern distribution and several diversity indices fisher shannon dominance evenness we were able to discriminate between five paleo environments paleo salinity was the most important environmental factor that governed the distribution of taxa in the korneuburg basin low diverse brackish environments yielded ammonia and aubignyna slightly reduced salinity conditions are dominated by ammonia with additional taxa and are more diverse normal marine salinities are indicated by the dominance of heterolepa gyroidinoides or bulimina and go along with a more balanced assemblage composition hypersaline conditions are characterized by cycloforina and ammonia and an intermediate diversity distribution freshwater samples are free of benthic foraminifera environmental changes and consequent ecological stress resulted in an overall low diverse paleo ecosystem salinity variations are interpreted as being caused by freshwater influx into the system seventeen combined increases and decreases of paleo salinity indicate a coupling with obliquity cycles and a linkage to regional climate changes the estuarine system of the korneuburg basin that lasted over 700 000 years shows distinct effects of the regional climate regimes on the local micro fauna

mountains and arid climates of middle latitudes simulations from a global climate model with and without orography have been used to investigate the role of mountains in maintaining extensive arid climates in middle latitudes of the northern hemisphere dry climates similar to those observed were simulated over central asia and western interior north america in the experiment with mountains whereas relatively moist climates were simulated in these areas in the absence of orography the experiments suggest that these interior regions are dry because general subsidence and relatively infrequent storm development occur upstream of orographically induced stationary wave troughs downstream of these troughs precipitation bearing storms develop frequently in association with strong jet streams in contrast both atmospheric circulation and precipitation were more zonally symmetric in the experiment without mountains in addition orography reduces the moisture transport into the continental interiors from nearby oceanic sources the relative soil wetness of these regions in the experiment without mountains is consistent with paleoclimatic evidence of less aridity during the late tertiary before substantial uplift of the rocky mountains and tibetan plateau is believed to have occurred

a reappraisal of episodic burial metamorphism in the andes of central chile the jurassic to miocene sequences of the central andes east of santiago reputedly show repeated cycles of episodic sub greenschist facies burial metamorphism that are identified by sharp breaks in metamorphic grade at major stratigraphic boundaries this paper presents the first detailed petrochemical analysis of these low grade metamorphic sequences by examining the progressive development of secondary minerals reaction progress in mafic phyllosilicates and topological variations in the low grade assemblages as a means of testing this model the results indicate a progressive increase from zeolite facies through to close to the onset of greenschist facies from miocene to jurassic rocks combined analysis of reaction progress in mafic phyllosilicates and petrochemical relationships of chlorite pumpellyite actinolite in metabasites provides no evidence for sharp metamorphic breaks at major stratigraphic boundaries integrating the results presented here with the most recent models of stratigraphic tectonic development of the central andes shows that the metamorphism took place in two episodes and was not episodic on a 40 million year cycle an absence of sharp breaks in metamorphic grade in any part of the succession as demonstrated here shows that the original petrographic establishment of low grade facies provided insufficient resolution of changes in metamorphic conditions to establish definitive evidence of such breaks accordingly this study suggests that re assessment of metamorphic breaks reputedly developed in other areas of the andean cordillera is imperative in order to resolve the questions raised here about the origin of the low grade metamorphism

plate convergence measured by gps across the sundaland philippine sea plate deformed boundary the philippines and eastern indonesia summary the western boundary of the philippine sea ph plate in the philippines and eastern indonesia corresponds to a wide deformation zone that includes the stretched continental margin of sundaland the philippine mobile belt pmb extending from luzon to the molucca sea and a mosaic of continental blocks around the ph australia sunda triple junction the gps geodyssea data are used to decipher the present kinematics of this complex area in the philippines the overall scheme is quite simple two opposing rotations on either side of the left lateral philippine fault clockwise to the southwest and counterclockwise to the northeast transfer 55 per cent of the ph sundaland convergence from the manila trench to the northwest to the philippine trench to the southeast further south 80 per cent of the ph sunda convergence is absorbed in the double subduction system of the molucca sea and less than 20 per cent along both continental margins of northern borneo finally within the triple junction area between the sundaland ph and australia plates from sulawesi to irian jaya preferential subduction of the celebes sea induces clockwise rotation of the sulu block which is escaping toward the diminishing celebes sea oceanic space from the eastwardadvancing ph plate to the south we identify an undeformed banda block that rotates counterclockwise with respect to australia and clockwise with respect to sundaland the kinematics of this block can be defined and enable us to compute the rates of southward subduction of the banda block within the flores trench and of eastward convergence of the makassar straits with the banda block the analysis made in this paper confirms that this deformation is compatible with the eastward motion of sundaland with respect to eurasia determined by the geodyssea programme but is not compatible with the assumption that sundaland belongs to eurasia as was often assumed prior to this study

late pleistocene and holocene sea level change along the australian coast abstract tectonically the australian continent is relatively stable and as such it provides a good platform for studying late pleistocene and holocene sea level change the observations indicate that present sea level was reached at about 6000 years ago and that since then level has remained constant to within a few metres considerable spatial variability in the amplitude of the emergence and in the time at which sea levels first reached their present values have been observed spatial variability has also been observed in the sea level during the last glacial maximum and during the late phase of the holocene transgression much of this variaiblity is the result of the earth s adjustment to the glacial melting in the late pleistocene early holocene time and the concomitant distribution of this meltwater into the oceans conclusions that are drawn from matching observations with this glacio hydro isostatic model include the following 1 the mantle viscosity increases with depth the average upper mantle viscosity is about 2 3 10 20 pa s and the average lower mantle defined as below 670 km depth viscosity is about 10 22 pa s the average lithospheric thickness for the coastal and offshore region is about 70 80 km lateral variations in these mantle parameters are indicated 2 the addition of melwater into the oceans did not cease 6000 years ago but continued at a reduced rate up to more recent times adding an amount of water equivalent to a 3 m sea level rise in this interval 3 the amplitude of the holocene emergence is a function inter alia of coastal geometry and significant variations occur over distances of a few hundred kilometres and more holocene highstands of 1 2 m are generally well developed at the continental margins but are less well developed or do not developed at all at offshore islands and reefs 4 variations in the time of maximum emergence also occur being earlier at upstream tidal river sites than at coastal sites at offshore reefs or islands the sea level curve lags the coastal curves by 1000 years or more 5 considerable spatial variability occurs in the sea levels at the time of the last glacial maximum with variations of up to 30 m occurring across the continental shelves 6 there is generally no need to invoke tectonic movements to explain the sea level data along the australian coast but possible exceptions occur for the perth region and for tasmania

holocene mangrove dynamics and relative sea level changes along the tanzanian coast east africa abstract there is continued uncertainty regarding the rate timing duration and direction of holocene sea level for the indian ocean and indeed the wider tropical realm we present the first synthesis and a new chronology for holocene relative sea level rsl using a range sediment cores retrieved from mangrove ecosystems in three locations along coastal tanzania this study applies the relationship of ratios between the key mangrove taxa of sonneratia bruguiera ceriops s bc ranging from 0 to 22 9 and sonneratia rhizophora s r ranging from 0 to 2 29 vegetation and altitude to interpret mangrove dynamics and refine the vertical errors associated with relative sea level change the variations in mangrove taxa ratios in the sediment cores obtained from each site shows mangrove development at different periods during the holocene from around 7900 cal yr bp an early to mid holocene rsl rise occurred from 7900 to 4600 cal yr bp that may have reached a higher level than present a lower rsl occurred after 4600 cal yr bp resulting in mangroves retreating seaward at all three study locations before a low magnitude rsl rise occurred between 4400 and 2000 cal yr bp another rsl rise is recorded at 500 cal yr bp before falling to a level lower than present at 100 cal yr bp there is evidence of a recent rsl rise recorded from mangrove ratios during the last century in addition the sedimentation rates among sites are relatively different due to different altitudinal ranges with freshwater input sediment supply and progradation having significantly more effect in the rufiji delta 2 1 10 9 mm cal yr 1 than at the zanzibar sites 0 3 6 6 mm cal yr 1

gps measurements of crustal deformation within the pacific australia plate boundary zone in irian jaya indonesia abstract global positioning system gps measurements made in 1991 1992 and 1993 provide preliminary estimates of slip distribution between the australian and pacific plates in irian jaya indonesia we interpret the gps results with constraints from earthquake mechanisms and slip vectors recent marine surveys and geology three gps sites in southeastern irian jaya show motions that are within 10 mm yr of the expected motion of australia a coast to coast n s baseline along 140 5 e crosses all known onland regions of active deformation but reveals no more than 15 mm yr of shortening and 20 mm yr of left lateral shear in the 27 month period the remaining 40 mm yr of expected convergence between the pacific and australian plates probably occurs at the new guinea trough gps sites on the island of biak at 136 e and at sorong near the western tip of bird s head at 131 e both move 90 100 mm yr in a wsw direction relative to irian jaya but less than 15 mm yr relative to each other these sites are on either side of the sorong fault and demonstrate that it is not presently the major boundary between the australian and pacific plates instead the plate boundary is now south of the sorong and biak sites earthquakes suggest possible structures that accomodate motion between bird s head and australia but the relative importance of them remains uncertain

pollen analysis of mangrove sediments as a sea level indicator assessment from tongatapu tonga increasing necessity for precision in holocene sea level records calls for definitive sea level indicators to be assessed these are reviewed by use of examples from the s w pacific and the technique of pollen analysis of mangrove sediments evaluated as a high resolution sea level indicator example is given how a fully calibrated sea level reconstruction can be gained from holocene mangrove peat units from tongatapu tonga by application of features established from a modern analogue of surface samples to interpret fossil pollen patterns

mangrove pollen of indonesia and its suitability as a sea level indicator we investigated the mangroves of southeast sulawesi indonesia to assess their potential as proxies for reconstructing sea level during the holocene initial investigations confirmed that the mangrove species demonstrate zonations parallel to the shoreline and are dominated by the family rhizophoraceae with avicennia heritiera and sonneratia also important constituents of the mangroves we investigated the vertical distributions of pollen assemblages at three sites partial cca analysis demonstrated that at all three sites elevation was a significant control on the distribution of pollen assemblages in surface samples we combined the three contemporary transects to develop a regional transfer function to explain the relationship between the surface assemblages and elevations using the maximum likelihood ml method the developed transfer function indicated mangrove pollen can be used as a precise indicator of past sea levels with an error of 0 22 m the transfer function was applied to two fossil cores from the wakatobi marine national park and evaluated using the modern analogue technique both cores showed similar patterns in changes of palaeo mangrove elevation and had modern analogues in the contemporary training set we conclude that mangrove pollen is a suitable proxy for reconstructing sea level in tropical environments

the dynamics of mangrove ecosystems changes in sea level and the strategies of neolithic settlements along the coast of oman 6000 3000 cal bc abstract this paper focus on the holocene palaeogeography of the ja alan coast from the 6th to the 4th millennium cal bc integrating the dynamics of mangroves lagoons khors estuaries and deltas with sea level change and the evidence from neolithic shell middens the distribution and maturation of mangrove ecosystems along the arabian coasts has varied considerably affected by physical forces such as sea level changes climate tidal amplitude and duration as well as the quantity of fresh water inflow associated with the monsoon systems along the arabian coast palaeo mangroves and lagoons today replaced by large sabkhas appear to be correlated to mid holocene fossil deltas and estuaries that currently function episodically depending on the rhythm of winter rains all these parameters have determined and impacted the location of settlement networks and the economic strategies of the first arabian farmers along the eastern arabian coast the mid holocene sea level highstand stability 5th millennium bc can be considered to be an optimum period for mangrove development and can be correlated with neolithic sites around the mangroves the decline of mangroves since 3000 2500 cal bc and further degradation is mainly attributed to the prevailing arid climate that reduced summer monsoon effects in the tropical area by favouring the extension of sabkhas we discuss these aspects based on new archaeological surveys excavations and geoarchaeological studies

stratigraphic record of holocene coseismic subsidence padang west sumatra 1 stratigraphic evidence is found for two coseismic subsidence events that underlie a floodplain 20 km south of padang west sumatra along the mentawai segment 0 5 s 0 3 s of the sunda subduction zone each earthquake is marked by a sharp soil mud contact that represents a sudden change from mangrove to tidal flat the earthquakes occurred about 4000 and 3000 cal years b p based on radiocarbon ages of detrital plant fragments and seeds the absence of younger paleoseismic evidence suggests that late holocene relative sea level fall left the floodplain too high for an earthquake to lower it into the intertidal zone our results point to a brief few thousand year window of preservation of subsidence events in tidal wetland stratigraphic sequences a result that is generally applicable to other emergent coastlines of west sumatra

millennial scale vegetation dynamics in an estuary at the onset of the miocene climate optimum article i nfo pollen analyses have been proven to possess the possibility to decipher rapid vegetational and climate shifts in neogene sedimentary records herein a c 21 kyr long transgression regression cycle from the lower austrian locality stetten is analysed in detail to evaluate climatic benchmarks for the early phase of the middle miocene climate optimum and to estimate the pace of environmental change based on the coexistence approach a very clear signal of seasonality can be reconstructed a warm and wet summer season with c 204 236 mm precipitation during the wettest month was opposed by a rather dry winter season with precipitation of c 9 24 mm during the driest month the mean annual temperature ranged between 15 7 and 20 8 c with about 9 6 13 3 c during the cold season and 24 7 27 9 c during the warmest month in contrast today s climate of this area with an annual temperature of 9 8 c and 660 mm rainfall is characterized by the winter season mean temperature 1 4 c mean precipitation 39 mm and a summer mean temperature of 19 9 c mean precipitation 84 mm different modes of environmental shifts shaped the composition of the vegetation within few millennia marshes and salt marshes with abundant cyperaceae rapidly graded into taxodiaceae swamps this quick but gradual process was interrupted by swift marine ingressions which took place on a decadal to centennial scale the transgression is accompanied by blooms of dinoflagellates and of the green alga prasinophyta and an increase in abies and picea afterwards the retreat of the sea and the progradation of estuarine and wetland settings were a gradual progress again despite a clear sedimentological cyclicity which is related to the 21 kyr precessional forcing the climate data show little variation this missing pattern might be due to the buffering of the precessional related climate signal by the subtropical vegetation another explanation could be the method inherent broad range of climate parameter estimates that could cover small scale climatic changes

fluid mineral equilibria in prehnite pumpellyite to greenschist facies metabasites near flin flon manitoba canada implications for petrogenetic grids a sequence of regional metamorphic isograds indicating a range from prehnite pumpellyite to lower amphibolite facies was mapped in metabasites near flin flon manitoba the lowest grade rocks contain prehnite pumpellyite and are cut by younger brittle faults containing epidote chlorite calcite isobaric temperature xco2 and pressure temperature constant xco2 diagrams were calculated to quantify the effects of co2 in the metamorphic fluid on the stability of prehnite pumpellyite facies minerals in metabasites containing excess quartz and chlorite prehnite and to a lesser extent pumpellyite are stable only in fluids with xco2 0 002 epidote chlorite calcite assemblages are stable our calculated phase relations are consistent with regional metamorphism in the flin flon area in the presence of an h2o rich fluid and a more co2 rich fluid in the later fault zones we believe that the potential effects of small amounts of co2 in the metamorphic fluid should be assessed when considering the pressure temperature implications of mineral assemblages in low grade metabasites

hydro isostasy and the sea level isobase of 5500 b p in north queensland australia abstract previous studies of holocene sea level in north queensland have been based on a variety of sea level related deposits with interpretations of mid holocene levels ranging from near zero up to 4 m above present we report data from 8 carefully controlled new sites located from the palm group northwards and extending into the gulf of carpentaria field evidence is from coral reef flats and prograded coastal deposits the highest sea level on inner shelf islands and mainland coast occurred 5500 yrs ago the results of this and of certain previous studies are reduced to a common reference surface or isobase which varies systematically in elevation across the region the isobase correlates strongly with predicted hydro isostatic deformation caused by postglacial sea level rise

miocene fossil hydrothermal system associated with a volcanic complex in the andes of central chile abstract cenozoic deposits in the andes of central chile have been affected by very low grade burial metamorphism at about 33 s in the cuesta de chacabuco area approximately 53 km north of santiago two oligocene and miocene volcanic units form a ca 1300 m thick rock pile the miocene unit corresponds to a volcanic complex composed of two eroded stratovolcanoes secondary mineral assemblages in both units were studied petrographically and using x ray diffraction and electron microprobe analyses most of the igneous minerals are wholly or partially preserved and the ubiquitous secondary minerals are zeolites and mafic phyllosilicates the alteration pattern observed is characterized by a lateral zonation in secondary mineralogy related to a lateral increase in temperature but not to stratigraphic depth the following three zones were established mainly based on the distribution of zeolites zone i comprises heulandite thomsonite mesolite stilbite and tri smectite zone ii contains laumontite yugawaralite prehnite epidote and chlorite and zone iii comprises wairakite epidote chlorite diopside biotite and titanite for each zone the following temperature ranges were estimated zone i 100 180 c zone ii 180 270 c and zone iii 245 310 c the alteration episode was characterized by a high p fluid p total ratio ca 1 0 although slightly variable a high geothermal gradient of ca 160 c km 1 and fluid pressures below 500 bars although temperature was the main control on the mineral zonation several interrelated parameters mainly fluid composition porosity and permeability were also important hot near neutral to slightly alkaline ph alkali chloride hydrothermal fluids with very low dissolved co 2 contents deposited the secondary minerals the alteration pattern is the result of depositing fluids in outflow regions from a hydrothermal system developed inside a volcanic complex during the miocene the hydrothermal system has been eroded to a maximum depth of 1 7 km

dating of in situ longhouse dubu daima posts in the kikori river delta refining chronologies of island village occupation in the lower kikori river delta papua new guinea this paper examines the chronologies of three abandoned village sites in an attempt to refine the timing of occupation of low lying mud islands of the lower kikori river delta gulf province papua new guinea png despite evidence for varying degrees of post depositional disturbance at all three sites meaningful chronological data can be obtained from the dating of in situ longhouse posts these new data suggest that although initial delta island occupation probably began around 400e500 years ago as an initial response to new opportunities relating to the hiri trade the very large villages ethnohistorically recorded for the delta islands may only have attained their impressive sizes somewhat later 2015 elsevier ltd and inqua

transition from the zeolite to prehnite pumpellyite facies in the karmutsen metabasites vancouver island british columbia

motion of the south bismarck plate papua new guinea the absolute motion of the south bismarck plate was first estimated by tregoning et al 1998 from three site velocities estimated from global positioning system gps observations we report an improved estimate of the euler vector for this plate using site velocities derived from new gps data which include the velocity of a site located 25 km from the pole of rotation the gps velocities of madang witu jacquinot bay and finschafen can be modelled to within 3 mm yr using a single pole of rotation located at 6 75 s 147 98 e with a clockwise rotation rate of 8 11 my the known tectonic features and available geophysical data surrounding the south bismarck plate can also be explained by a rotation of the south bismarck plate about this pole

stratigraphic evidence for an early holocene earthquake in aceh indonesia abstract the holocene stratigraphy of the coastal plain of the aceh province of sumatra contains 6 m of sediment with three regionally consistent buried soils above pre quaternary bedrock or pre holocene unconsolidated sediment litho bio and chronostratigraphic analyses of the lower buried soil reveals a rapid change in relative sea level caused by coseismic subsidence during an early holocene megathrust earthquake evidence for paleoseismic subsidence is preserved as a buried mangrove soil dominated by a pollen assemblage of rhizophora and or bruguiera ceriops taxa the soil is abruptly overlain by a thin tsunami sand the sand contains mixed pollen and abraded foraminiferal assemblages of both offshore and onshore environments the tsunami sand grades upward into mud that contains both well preserved foraminifera of intertidal origin and individuals of the gastropod cerithidea cingulata radiocarbon ages from the pre and post seismic sedimentary sequences constrain the paleoearthquake to 6500 7000 cal yrs bp we use micro and macrofossil data to determine the local paleoenvironment before and after the earthquake we estimate coseismic subsidence to be 0 45 0 30 m which is comparable to the 0 6 m of subsidence observed during the 2004 aceh andaman earthquake on aceh s west coast

rainfall patterns and the distribution of coals and evaporites in the mesozoic and cenozoic abstract paleoclimatologists have adequately demonstrated over the last twenty years that the distribution of climatically sensitive sediments can be related to present day climatic zones that are roughly parallel to latitude for example coals were deposited at paleolatitudes that correspond to the present day rainy zones at the equator and at about 55 n and 55 s indicating that those zones were present in the past from this it can be concluded that atmospheric circulation has not been radically different from its present configuration despite some apparently great differences in some climatic parameters such as the equator to pole temperature gradient nevertheless the zonal model for predicting the distribution of climatically sensitive sediments is not wholly adequate although general atmospheric circulation may not have been radically altered from its present pattern it would have differed in some respects because the paleogeography was different from the present geography therefore we have constructed what we believe are more realistic maps of the distribution of rainfall through time these maps are based on maps of atmospheric circulation that have been successfully used to predict the distribution of some petroleum source beds and phosphorites we have compared the predicted distribution of rainfall to the distribution of coals and evaporites for each of seven geologic stages the circulation rainfall maps were more successful than the zonal model for predicting the distribution of evaporites and coals for times when the paleogeography would have maximized the development of a monsoonal circulation which most effectively disrupts the general zonal pattern for times when a monsoonal circulation would not have been important the zonal model adequately predicted the distribution of these rocks

mangrove swamp stratigraphy and holocene transgression grand cayman island west indies abstract the island of grand cayman in the western caribbean has an extensive mangrove swamp vegetation numerous cores have been taken in and adjacent to these swamplands and these reveal that the swamps are generally underlain by a transgressive sequence of sediments the basal unit of this sequence consists of a laminated or non laminated crust formed in a subaerial environment locally these crusts are overlain by plastic mud deposited in seasonally flooded environments mangrove peat forms the upper unit of the transgression within most of the swamplands overlying the other units where these are found and reaching thicknesses of more than 4 m the final stage of marine incursion is recorded to the east of north sound where in water depths of 10 200 cm shelly mud occurs overlying mangrove peat in contrast to this to the west of north sound there is a regressive sequence in which shelly marl underlies a localised sea grass peat and mangrove peat this regressive sequence records local progradation of mangroves into marine environments the transgressive sedimentary sequence on grand cayman is similar to transgressive sedimentary sequences described from the florida everglades mangrove complex florida bay and the belize shelf on grand cayman however the stratigraphy is less complex because there are not extensive freshwater peat forming environments or intertidal and supratidal carbonate environments samples of mangrove peat were collected from the peat bedrock interface along a surveyed profile across barkers peninsula on grand cayman radiometric dating of these implies that sea level was approximately 185 cm below the present level at least 2100 years bp comparison of these dates with dates on mangrove peat from elsewhere suggests that submergence on grand cayman has taken place at a similar rate to that in florida

mangrove vegetation changes on holocene terraces of the doce river southeastern brazil article i nfo high resolution sedimentological geochemical and pollen analysis on sediment core from the coastal plain of the doce river southeastern brazil revealed changes in the depositional system and vegetation caused by combined action of oscillations in relative sea level rsl and sedimentary supply during the holocene two main phases were discerned using sedimentary features 13 c 15 n total organic carbon toc total ni trogen n c n and cluster analysis of pollen data temporally synchronized with radiocarbon age dating the data indicates the presence of a lagoon system surrounded by a tidal plain colonized by mangroves and its sedimentary organic matter sourced from c4 plants between 8050 and 7115 cal yr bp however during the mid and late holocene the mangroves shrank and freshwater vegetation expanded c3 plants proba bly due to a marine regression during this phase the development of a lacustrine environment was followed by the colonization of herbs trees and shrubs the continuous sediment infilling into the lake allowed the ex pansion of a herbaceous plain as seen today this geomorphologic and vegetation evolution is in agreement with the mid holocene rsl maximum above present rsl and subsequent fall to the present time

low grade regional metamorphism in the mesozoic cenozoic volcanic sequences of the central andes all the mesozoic and cenozoic volcanic rocks of the central andes from southern ecuador to central chile except recent ones have been affected by episodes of regional metamorphism without change in texture and structure the metamorphism which ranges from low zeolite to greenschist facies can be classified as burial metamorphism because there is an overall increase in metamorphic grade with stratigraphic depth in the individual volcanic sequences separated by regional unconformities some sequences display metamorphic patterns transitional to ocean floor and to geothermal field types reflecting variations along and across the andes in tectonic setting and thermal gradients volcanism was closely followed by metamorphism during each cycle characterizing the geological history of the central andes the episodic nature of the metamorphism has led to breaks in metamorphic grade at regional unconformities and repetition of facies series where strata of higher grade may even overlie those of lower grade the existence of permeability controlled distribution patterns of secondary minerals within individual flows shows that gradients of chemical activity rate of reaction and pfluid were acting in addition to temperature and p tot overall gradients during the regional metamorphism the alteration is accompanied by chemical changes and disturbances of the k ar and rb sr isotope systems similarities between mesozoic facies series in the western and eastern flanks of the andes are consistent with a mechanism of ensialic spreading subsidence

holocene pollen records from caution bay southern mainland papua new guinea this study presents new palynological data from caution bay south central papua new guinea png it explores holocene mangrove transitional events along a tide dominated shoreline and expands reconstructive detail for the wider southern png lowlands coinciding with recent regional archaeological research this study also holds implications for interpretations of the holocene settlement of caution bay and long term people landscape interactions data demonstrate a late holocene mangrove to mudflat transition with vegetation patterns largely a function of low sediment loading sedimentary redistributions and salinisation upon sea level decline c 2000 cal yr bp these trends appear unique to caution bay highlighting a variety of holocene shoreline vegetation changes along the png south coast each dependent on geomorphologic setting and hydrological fluxes further work is required to elucidate vegetation change inland of the coastal zone greater understanding of burning patterns and an archaeological collaboration are required to determine more concisely dryland plant spatial and temporal variability

regional and local patterns of low grade metamorphism in the north shore volcanic group minnesota usa the north shore volcanic group in northern minnesota is part of the middle proterozoic keweenawan sequence one of the largest plateau lava provinces in the world the primary geochemistry of the basalts suggests that volcanism occurred in an intracontinental rift environment the subaerial lava flows mainly amygdaloidal olivine tholeiites and tholeiites have undergone low grade metamorphism from zeolite to lower greenschist facies on the basis of alteration phases replacing the primary magmatic minerals infilling amygdales and veins and replacing secondary minerals the following zones have been distinguished 1 thomsonite scolecite smectite 2 heulandite stilbite smectite 3 laumontitechlorite albite 4 laumontite chlorite albite prehnite pumpellyite and 5 epidote chlorite albite actinolite zone in addition to the overall zonation based on mineral parageneses zonations in the composition of the ab content of the newly formed albite replacing primary ca rich plagioclase and of the newly formed mafic phyllosilicates are observed within the sequence and within single flows mafic phyllosilicates in the upper part of the sequence mainly smectites and mixed layer smectite chlorites display high si and ca na k contents whereas in the lower part of the sequence the amounts of si and ca na k are markedly lower mainly chlorites and mixed layer chlorite smectites similar zonations are observed within the individual flows the albite content of the newly formed plagioclase is highest and the si and ca na k content of the phyllosilicates lowest in the amygdaloidal flow top while the opposite is true for the massive flow interior the above features suggest that the overall pattern is one of burial type metamorphism associated with extension in the rift setting in detail the mineral assemblages are controlled not only by the stratigraphic position but also by the flow morphology controlling permeability whose effect on the assemblages is most pronounced in the stratigraphically upper parts this suggests that at the first stages of alteration lowest grade the patterns of fluid flow were important effects in controlling the assemblages at greater burial depth assemblages are more homogeneous perhaps representative of a more even and pervasive flow pattern using the observed assemblages at face value to define grade and or facies different conditions would be assigned within the different morphological flow portions thus at low grade metamorphic conditions it is essential to integrate assemblages from different morphological flow portions in order to define satisfactorily the overall metamorphic conditions

late pleistocene and holocene sea level change in the australian region and mantle rheology summary spatial and temporal variations in sea level are produced by the melting of the late pleistocene ice and by the earth s response to the redistribution in surface loads by examining different parts of the sea level curves of the past 20 000 yr from geographically widely distributed regions it becomes possible to constrain models of the melting history of the ice sheets and of the earth s rheology observations from sites away from the former arctic ice sheets such as the australian and south pacific region are particularly important for constraining the total meltwater volumes added into the oceans in the past 20 000 yr and the rates at which this occurred these observations indicate that the antarctic ice sheets provided a significant contribution to the sea level rise at a rate that was approximately synchronous with the melting of the laurentide ice sheet except for the interval 9000 6000 yr ago when it may have lagged behind minor melting of the antarctic ice sheet appears to have continued throughout the late holocene differential observations of the late holocene sea level change recorded at sites in the same region are particularly useful for estimating parameters describing the earth s non elastic response to surface loading the effective parameters used here are a lithospheric thickness an upper mantle viscosity and a lower mantle viscosity describing the response below 670 km depth with the observations used here it is not possible to separate the lithospheric thickness h from the upper mantle viscosity and the viscosity results are based on the assumption that 50 h 100 km neither do these observations provide a resolution of the depth dependence of viscosity in the upper mantle and the resulting estimates are effective parameters only differential sea levels along continental margins and along the shores of large gulfs and bays constrain the effective upper mantle viscosity to be about 1 2 1020 pa s 1 while differential values from islands of different sizes are suggestive of a somewhat lower value the lower mantle taken to be below 670 km depth viscosity is about two orders of magnitude greater than this the estimated ice and rheological models explain many of the holocene sea level observations throughout the australian and southern pacific region the tilting of continental margins as exemplified by observations of variable amplitudes of the holocene high stands and the variable times at which sea levels first reached their present level along the north queensland coast and great barrier reef is well represented by these models differential holocene sea levels observed along the narrow spencers gulf of south australia are also well explained by the models and in neither case is it necessary to invoke tectonic motions predicted late holocene sea levels at small to medium sized islands are characterized by small amplitude high stands that reached their maximum values about 4000 2000 yr ago consistent with observations from the society cook and tuamotu islands

inversion of an oligocene volcano tectonic basin and uplifting of its superimposed miocene magmatic arc in the chilean central andes first seismic and gravity evidences abstract a new structural model is presented for the cenozoic part of the main range east of santiago a chain made up of thick miocene ignimbrites and andesitic lavas overlying primitive oligocene volcanoclastics deposited on a thin continental crust because the latter coya machali formation locally show tight folding close to the margins of the miocene volcanics they had previously been described as deformed prior to construction of the arc our field observations analysed along two profiles at 33 and 34 15 s however support the conclusion hinted at by ongoing geochronological and geochemical studies deformation of both formations is synchronous and related to late miocene inversion of the coya machali intra arc basin uplift of the rigid arc rocks and part of its volcanoclastic basement took place mainly along two northward shallowing boundary structures that seem to share a lower decollement the eastern fierro out of sequence thrust and a series of western back thrusts that resemble triangle zones seismic data obtained from el teniente porphyry copper mine 34 s rockbursts and two gravimetric profiles at the western end of the southern profile are compatible with a decollement located at that locality 2 3 km under the surface

holocene coral reef terraces and coseismic uplift of huon peninsula papua new guinea abstract as many as six levels of emerged holocene coral terraces occur along 40 km of coastline on the huon peninsula papua new guinea recording uplift history since culmination of the postglacial transgression the holocene reef crest ca 6000 yr b p is tilted down to the northwest parallel to the coast and concordant with the deformation of the last interglacial coral reef terrace and descends from 23 to 12 m in the study area the pattern and rate of deformation have been uniform in the late quaternary because average uplift rates have remained the same since the last interglaciation the holocene terraces described here are erosional features with regressive encrusting corals developed upon the holocene transgressive reef the multiple levels represent episodic probably coseismic uplift which has occurred repeatedly in the last ca 6000 yr significant longshore variation in the age of the lowest terrace from 1700 to 2500 yr b p suggests independent coseismic uplift on different sectors of the coast this is supported by age height relationships of the higher holocene terraces nonlinear uplift during the holocene with recurrence intervals increasing toward the present is clearly recorded by the regressive terraces in each subregion some of the holocene regressive terraces grade laterally into fluvial terraces capped with debris flow deposits probably reflecting seismically triggered mass movement

holocene mangrove dynamics in makoba bay zanzibar abstract pollen and charcoal analyses on sediment cores retrieved across an altitudinal transect in makoba bay zanzibar tanzania set within a chronology provided by 11 radiocarbon dates are used to reconstruct holocene mangrove ecosystem dynamics using the changing ratio of the key mangrove taxa sonneratia bruguiera ceriops s bc relative changes in past sea level are inferred the interpretation of the pollen record is guided by an initial assessment of modern pollen vegetation and vegetation to environmental relationships mangrove communities in makoba bay are recorded from at least the early holocene in what was a similar environment to the present day mangroves migrated landward probably in relation to a sea level rise until the mid holocene as the seaward and central core locations developed as a lower intertidal mangrove area a phase of lower sea level occurred from the mid holocene to 1450 1550 cal yrs bp characterised by the mangrove communities retreating seaward after 1450 1550 cal yrs bp sea level rose again and greater inundation frequency caused mangroves to shift landward gradually falling until reaching the present sea level the recent decrease of mangrove species rhizophora mucronata may result from increasing anthropogenic influences in the mangrove ecosystems during the last centuries as supported by an increase in charcoal

vegetation change following mid holocene marine transgression of the torres strait shelf a record from the island of mua northern australia the pollen and sedimentary record from a coastal backdune swamp on the island of mua torres strait australia is presented a 4 55 m core collected from the swamp centre provides a record of vegetation and landscape change spanning the postglacial marine transgression to present prior to 6000 radiocarbon years before present yr bp results show mangrove vegetation encroaching on the core site periodically displacing non mangrove taxa until the establishment of an extensive mangrove forest between 6000 yr bp and 3000 yr bp within the mangrove community a transition from lower tidal rhizophora forest to an upper intertidal ceriops community is evident this is followed by the development of the current herbaceous freshwater swamp in the late holocene the dryland vegetation record is dominated by sclerophyll and rainforest elements with strongest forest representation occurring around the mid holocene before a decline in tree density and the establishment of open woodlands in the late holocene the data suggest vegetation change accompanied marine transgression and a humid mid holocene climate before stabilization of sea levels and the initiation of dominant on shore catchment processes signalling drier climatic conditions and possible human activity

episodic burial metamorphism in the andes a viable model burial metamorphism of regional extent throughout mesozoic to cenozoic sequences in the andean mountain belt has been attributed previously to a unique model of metamorphic development involving episodic 40 m y cycles of extensional basin formation burial metamorphism and then exhumation a main premise of this model is that breaks in metamorphic grade occur at major stratigraphic unconformities so marking successive metamorphic cycles this model is tested in a mesozoic cenozoic sequence east of santiago where three metamorphic episodes have been reported on the basis of sharp breaks in metamorphic grade at two main unconformities in metabasites from this area reaction progress in mafic phyllosilicates shows a continuum across the sequence without breaks at the unconformities there are differences in mineral assemblages between the various stratigraphic units from which contrasting subgreenschist facies can be recognized however consideration of the controls on mineral paragenesis at subgreenschist facies conditions demonstrates that these different facies cannot be used as evidence of sharp breaks in metamorphic grade at unconformities as has been reported in many previous publications thus metamorphic breaks within this andean section cannot be confirmed accordingly models of andean burial metamorphism linked to episodic tectonic cycles throughout the mesozoic and cenozoic appear unfounded

holocene palynology and sea level change in two estuaries in southern irian jaya southern new guinea leads the continental australian plate into convergence to form the new guinea highlands extensive inter tidal deltas are typical of much of this low gradient equatorial coastline in two adjacent estuaries in irian jaya west papua this study uses present elevations of mangrove species zones as a finite indicator of holocene sea levels from pollen diagrams of estuarine cores all cores showed mangroves at levels well below the present tidal range with landward species zones being replaced over time by seaward zones results show tectonic subsidence in the recent period with late holocene relative sea level rise of 0 67 mm year 1

a palynological investigation of holocene vegetation change in torres strait seasonal tropics of northern australia the islands of torres strait occupy a shallow area of submerged continental shelf narrowly separating cape york peninsula australia from new guinea the human history of torres strait is unique with respect to mainland northern australia island vegetation however exhibits a strong affinity with the environments of the western lowlands regions of cape york peninsula and with the vegetation of seasonal tropical australia in general cape york peninsula is both climatically and biologically diverse yet few pollen studies have been carried out in its seasonally tropical environments a summary presentation of palynological results tracing the nature of vegetation change in torres strait offers a possible framework for vegetation changes in similar environments on mainland australia and also provides an opportunity to explore the relationship between quaternary change in humid tropical australian environments and their seasonal tropical counterparts six pollen records from torres strait provide evidence of vegetation change and fire history over approximately the last 8000 years near shore sediments reveal a holocene succession in vegetation incorporating lower tidal mangrove upper tidal mangrove saltmarsh and freshwater swamp communities extensive stable mangrove communities dominated coastal torres strait between approximately 6000 and 3000 radiocarbon years before present yr bp inland the strongest myrtaceae forest and rainforest representation occurs around the mid holocene only to be replaced by open sclerophyll woodlands as tree density and diversity decline in the last 3000 years the development of continuous island freshwater swamp conditions at the coast and inland is similarly restricted to the late holocene c 2600 yr bp and fire as a prominent feature in the torres strait environment is also a relatively recent phenomenon comparisons with regional mainland australian palynological records reveal a degree of consistency in results from torres strait suggesting a similarity in late quaternary trends through australian humid and seasonally tropical environments a number of differences however are also apparent highlighting a degree of diversity which warrants further attention

mangrove vegetation responses to holocene climate change along konkan coast of south western india abstract the pollen signatures preserved in the mangrove sediments provided records of species variation over a period of time with past climate and sea level changes the airoli profile has a late pleistocene sequence and all the other studied profiles and intervals cover the holocene only the absence of mangrove signatures during the late pleistocene interval is attributed to a relatively low sea level the ideal conditions for mangrove development along konkan prevailed during middle holocene when the first extensive mangrove swamps appeared in sindhudurg dhamapur hadi area particularly between 7220 and 4770 yrs bp this period coincides with the holocene climate optimum hco when monsoon asia witnessed much higher precipitation however the mangroves responded to environmental changes due to relative abundance of fresh water leading to change in species composition two different scenarios of mangrove response during the late holocene one in dhamapur and the other in palm beach are found to be significant the rhizophora sonneratia transition from early mid holocene to late holocene is considered to be the most distinctive feature the decline of mangroves since 3500 yrs bp and further degradation has been attributed to the prevailing arid climate and weakening trends of the monsoon until 1500 yrs bp however there seems to be a positive trend in emergence of mangroves in the least disturbed areas of south konkan attributed to strengthening of summer monsoon in the recent past

tectono stratigraphic evolution of the andean orogen between 31 and 37 s chile and western argentina fil charrier reynaldo universidad de chile facultad de ciencias fisicas y matematicas departamento de geologia chile universidad andres bello chile

a new petrogenetic grid for low grade metabasites abstract we have used internally consistent thermodynamic data to present calculated phase equilibria for the system na2o cao mgo al2o3 sio2 h2o ncmash in the range 0 500 c and 0 1 10 kbar involving the phases anorthite glaucophane grossular heulandite jadeite laumontite lawsonite paragonite prehnite pumpellyite stilbite tremolite wairakite zoisite with excess albite clinochlore quartz and pure water average activity terms derived from published mineral chemical data were included for clinochlore glaucophane prehnite pumpellyite tremolite and zoisite the new petrogenetic grid delineates stability fields and parageneses of common index minerals in zeolite prehniteactinolite prehnite pumpellyite pumpellyite actinolite blueschist and greenschist facies metabasites the stability fields of mineral assemblages containing prehnite pumpellyite epidote actinolite albite chlorite quartz were analysed in some detail using activity data calculated from five specific samples for example the prehnite actinolite facies covers a p t field ranging from about 220 to 320 c at pressures below 4 5 kbar the transition from the prehnite actinolite and pumpellyite actinolite to greenschist facies occurs at about 250 300 c at 1 3 kbar and at about 250 350 c at 3 8 kbar p t fields of individual facies overlap considerably due to variations in chemical composition

radiocarbon dating of mangrove sediments to constrain holocene relative sea level change on zanzibar in the southwest indian ocean mangrove sedimentary deposits are sensitive to changes in sea level and can be used to reconstruct mid to late holocene sea level fluctuations in intermediate and far field locations distant to t

compositional variations in mafic phyllosilicates from regional low grade metabasites and application of the chlorite geothermometer mafic phyllosilicates in metabasites affected by low grade regional metamorphism from wales and eastern north greenland show variations in their structure and chemistry these variations are related to four mineral zones in these metabasites which are recognized on the presence absence of various key calc silicate minerals and also actinolite zones 1 and 2 equate with the zeolite facies zone 3 with the prehnite pumpellyite facies or prehnite actinolite facies in rocks with appropriate bulk rock composition and zone 4 with the greenschist facies whilst variations in fe fe mg in chlorite correlate closely with fe fe mg ratios in the whole rock other chemical variations are clearly unrelated to whole rock compositions contents of aliv are seen to increase systematically in samples from zone 1 through to zone 4 which relate to an increase in temperature calibration of alteration temperatures calculated using the chlorite geothermometer based on aliv contents developed for meta andesites in the los azufres geothermal system mexico against x values an estimate of the proportion of chlorite to swelling component in the mafic phyllosilicates shows a decrease in the swelling component in passing from zone 1 to zone 4 i e with an increase in temperature calculated temperatures compare favourably with published stability estimates for the various key calc silicates and actinolite these data indicate that the chlorite geothermometer although developed for meta andesites from a hydrothermal system does show a correlation with temperatures estimated from calc silicate assemblages in metabasites affected by low grade metamorphism developed on a regional scale

mid holocene mangrove succession and its response to sea level change in the upper mekong river delta cambodia abstract middle holocene vegetation and mangrove successions are clearly evident in the palynological records of two cores from the upper mekong river delta in cambodia spanning from 9 4 to 6 3 cal ka bp the cores mainly record a transgressive sequence from floodplain freshwater marsh to tidal flat which was overlain by mangrove corresponding to the decelerated sea level rise at 8 3 cal ka bp pioneer mangrove species sonneratia alba and sonneratia caseolaris appeared in the sediments and then was replaced by regressive mangrove succession containing upward increasing abundances of rhizophora apiculata and bruguiera spp high salinity and flooding tolerant community s alba was developed at the western core site psg at 8 2 cal ka bp and the eastern core site pk at 7 5 cal ka bp the time difference of s alba appearance between the two sites might be resulted from the complexity of sedimentary environment where a higher sediment supply was provided to the western floodplain than to the eastern floodplain after 7 5 cal ka bp aggradational stacking of intertidal sediments of which the thickness is larger than the present maximum tidal range may have resulted from continuous sea level rise during 7 5 7 0 cal ka bp

subsidence of the gulf of papua in the cenozoic abstract the gulf of papua between papua new guinea and the northeastern australian margin contains thick cenozoic strata we have examined the subsidence history using data from eight wells in the gulf of papua four are in the western gulf region overlying paleozoic basement and four are in the eastern gulf near the aure trough backstripping results show two subsidence episodes for the western wells the first episode from early cenozoic to oligocene may be due to a small amount of lithospheric stretching associated with the opening of the coral sea the second from early miocene to the present has a substantially higher subsidence rate which cannot be explained by a paleocene rifting event the late oligocene late miocene episode of rapid subsidence in the aure trough to the east appears to be a significant factor affecting the subsidence of the western gulf of papua during this period to test this we computed the expected deflection from flexure due to the load of the aure trough strata and find a profile similar to that observed the model used had an effective elastic thickness similar to those for rifted continental margins thus implying a relatively weak lithosphere in addition the predicted position of the forebulge in the western gulf occurs where oligocene strata are absent suggesting post depositional uplift and hence facilitating the growth of early miocene reefs

reconciliation of late quaternary sea levels derived from coral terraces at huon peninsula with deep sea oxygen isotope records a major discrepancy between the late quaternary sea level changes derived from raised coral reef terraces at the huon peninsula in papua new guinea and from oxygen isotopes in deep sea cores is resolved the two methods agree closely from 120 ka to 80 ka and from 20 ka to 0 ka ka 1000 yr before present but between 70 and 30 ka the isotopic sea levels are 20 40 m lower than the huon peninsula sea levels derived in earlier studies new high precision u series age measurements and revised stratigraphic data for huon peninsula terraces aged between 30 and 70 ka now give similar sea levels to those based on deep sea oxygen isotope data planktonic and benthic 18o data using the sea level and deep sea isotopic data oxygen isotope ratios are calculated for the northern continental ice sheets through the last glacial cycle and are consistent with results from greenland ice cores the record of ice volume changes through the last glacial cycle now appears to be reasonably complete