late pleistocene and holocene subtropical vegetation dynamics recorded in perched lake deposits on fraser island queensland australia abstract the dune system of fraser island in subtropical queensland australia contains numerous perched lakes with organic rich sediments these lakes are located in the subtropics and their water levels are strongly influenced by precipitation the lakes act as natural rainfall gauges which make them highly sensitive to environmental change paleoecological and paleoclimatological investigations are performed on sediment cores from lake allom a small perched lake on central fraser island a detailed chronology is based on a series of closely spaced ams radiocarbon dates supplemented with sedimentological information based on extrapolation the chronology indicates an age range from 56 14c kyr bp to present with a major hiatus occurring during the last glacial maximum pollen analysis of the lake allom sediment record reveals strong changes between rainforest and open woodland vegetation the holocene portion of the record shows a stepwise vegetation development from dry conditions in the early holocene to high lake levels and increasing forest between 5 5 and 3 cal kyr bp at 3 2 cal kyr bp a large diversification occurred towards the present day heterogeneous sub tropical rainforest vegetation followed by a small rainforest decline at 0 45 cal kyr bp additionally charcoal analysis indicates increases in fire occurrence contemporaneously with periods of drier vegetation and or low lake levels part of the reconstructed vegetation changes can be related to local and regional factors including forest succession dune formation sea level rise and human impact comparison with paleoclimate records from tropical and temperate regions indicates that the temporal and spatial dynamics of vegetation changes in eastern australia are primarily controlled by climate variability particularly the increasing activity of the el nino southern oscillation enso during the late holocene caused greater climate variability in eastern australia resulting in more heterogenous vegetation cover

formation and evolution of the tancheng lujiang wrench fault system a major shear system to the northwest of the pacific ocean abstract in the northwestern peri pacific tectonic belt on the continental margin of east asia there is a series of major faults trending ne nne i e the tancheng lujiang wrench fault system this fault system extends more than 5000 km with a width of 800 1000 km in the continent and a general strike of n30 e on the basis of the results of special research on the major faults and a lot of new information about the fault system the authors discuss early mesozoic triassic jurassic period sinistral transcurrent faulting in the different regions it is suggested that in the eastern continent of east asia the e w trending tectonic pattern of the paleozoic and beginning of the mesozoic appear in the nuclei of the sino korean continent massif and the yangtze continent massif these ancient continent massifs accreted both southwards and northwards which finally led to their collision and suturing to the angura continent massif later this tectonic framework was changed greatly by the tancheng lujiang wrench fault system along which left lateral horizontal displacement of 1000 1500 km took place since the mesozoic the dislocation and deformation of horizontal displacement of the tancheng lujiang fault system produced a series of structures trending ne nne in the continental margin which have greatly transformed the ancient structures of the preceding mesozoic this is an important diktyogenese in the continent of east asia during the horizontal displacement motion of these faults the folds nappes and decollement structures pull apart basins and subductions within the continent occurred in the continent at the same time some large sinistral ductile shear zones of horizontal displacement appeared the depth of the deformed horizon of ductile shear which belongs to simple shear was controlled by the tectonic element and distance away from the continental margin whilst the ductile shear deformation occurred the fault dynamo thermal metamorphism and the fault remelting took place and magma activity appeared within the continent in the mesozoic the fault zones used to be high energy zones and recently became the seismic belts within the continent formation of the tan lu fault system was due to the collision between the southern and northern blocks its large sinistral horizontal displacement in the mesozoic was closely related to the kula plate moving northwards therefore the continent disintegrated by shearing which produced some new terranes the shear edge belt was formed between the continent and ocean the change of relative motion between the continent and pacific ocean plate transformed the tan lu fault system into first extension and then compression clarifying the characteristics of the tan lu fault system is an important key in understanding the evolution of the east asia continent since the mesozoic

beach ridges and prograded beach deposits as palaeoenvironment records abstract beach ridges are landforms commonly developed on prograded coasts with beach shorelines a sequence of beach ridges coupled with their subsurface deposits can be regarded as a time series of coastal evolution methodological advances in field surveying and chronology applicable to beach ridges have led to detailed palaeoenvironmental reconstructions to be derived from such sequences this paper reconsiders the basic aspects of beach ridges and deposits which need to be properly understood for their comprehensive interpretation in a palaeo environmental context it also reviews case studies in which beach ridge sequences have been used to unveil past sea level history catastrophic events and climate changes proposed formative processes of beach ridges include 1 progradation of sandy beach and berm formations in relation to fairweather waves coupled with aeolian foredune accumulation 2 building of gravel ridges by storm waves 3 welding of longshore bars beach ridge formation through sea level oscillation is thought to be questionable and caution is suggested for this process when undertaking palaeoenvironmental reconstruction beach deposit stratification is known to dip either landwards or seawards but landward dips are uncommon seaward dipping stratification is formed in relation to beachface progradation and is usually dissected in places by erosion surfaces resulting from episodic beach retreat the boundary between the foreshore and the underlying shoreface is well defined only in the case that longshore bars lead to complex bedding structure relative to that of the foreshore reliable chronology of beach ridges can be determined by radiocarbon and optically stimulated luminescence osl dating radiocarbon dating of articulated shells which are considered not to be extensively reworked provides robust results but osl dating is more useful as it enables direct dating of sediment grains it is noted that there are restrictions in chronological resolution and continuity inherent to beach ridge and beach deposits the plan view geomorphic expression of beach ridges typically consists of ridge sets with multi decadal intervals whereas their internal sedimentary structures define shorter time scales records of beach sedimentation and erosion are likely to be reworked by episodic high magnitude beach retreat and the resultant record of the net progradation is likely to be sporadic and discontinuous the height of sandy beach ridges is often variable due to differing degrees of aeolian sand accumulation and they are thus not used as sea level indicators unless purely wave built gravel ridge height is a relatively reliable indicator of sea level but can vary in response to storminess fluctuations subsurface sediment facies boundaries are preferred as sea level indicators and those proposed include boundaries of aeolian beach foreshore shoreface and upper lower shorefaces catastrophic events are expressed in both erosional and depositional records erosion surfaces or scarp imprints revealed in a cross section of beach deposits indicate storm or tsunami events however erosional events are likely to rework previous records of sedimentation and even other erosional events and thus the apparent history decoded from the resultant deposits tends to be biased several attempts for estimating the frequency and intensity of prehistoric cyclones rely on assumed relationships between the level of coarse sand beach ridges and cyclone inundation the formative process of coarse sand ridges remains uncertain and needs to be clarified as it constitutes the fundamental basis of these attempts the growth rates of beach ridge systems are expected to reflect fluctuations in river sediment discharge to the coast and in aeolian sand flux due to onshore winds both of which are affected by climate change assessment of the growth rate is potentially improved by ground penetrating radar survey of subsurface structure and by detailed chronology orientation of beach ridges reflects long term trends in wave direction inferred relationships between beach ridges and cyclic fluctuations of sea level and climate rely on weak assumptions and are not substantiated by rigid chronological evidence and thus remain highly questionable correlation between the inherently decadal signal of beach ridge intervals and possible climate cycles such as sunspot activity is probably coincidental as it lacks causal explanations

geometry and kinematics of adhesive wear in brittle strike slip fault zones abstract detailed outcrop surface mapping in late paleozoic cataclastic strike slip faults of coastal maine shows that asymmetric sidewall ripouts 0 1 200 m in length are a significant component of many mapped faults and an important wall rock deformation mechanism during faulting the geometry of these structures ranges from simple lenses to elongate slabs cut out of the sidewalls of strike slip faults by a lateral jump of the active zone of slip during adhesion along a section of the main fault the new irregular trace of the active fault after this jump creates an indenting asperity that is forced to plow through the adjoining wall rock during continued adhesion or be cut off by renewed motion along the main section of the fault ripout translation during adhesion sets up the structural asymmetry with trailing extensional and leading contractional ends to the ripout block the inactive section of the main fault trace at the trailing end can develop a sag or half graben type geometry due to block movement along the scallop shaped connecting ramp to the flanking ripout fault leading contractional ramps can develop thrust type imbrication and forces the humpback geometry to the ripout slab due to distortion of the inactive main fault surface by ripout translation similar asymmetric ripout geometries are recognized in many other major crustal scale strike slip fault zones worldwide ripout structures in the 5 500 km length range can be found on the atacama fault system of northern chile the qujiang and xiaojiang fault zones in western china the yalakom hozameen fault zone in british columbia and the san andreas fault system in southern california for active crustal scale faults the surface expression of ripout translation includes a coupled system of extensional trailing ramps as normal oblique slip faults with pull apart basin sedimentation and contractional leading ramps as oblique thrust or high angle reverse faults with associated uplift and erosion the sidewall ripout model as a mechanism for adhesive wear during fault zone deformation can be useful in studies of fault zone geometry kinematics and evolution from outcrop to crustal scales

deglacial sea level record from tahiti corals and the timing of global meltwater discharge the timing of the last deglaciation is important to our understanding of the dynamics of large ice sheets1 and their effects on the earth s surface2 3 moreover the disappearance of the glacial ice sheets was responsible for dramatic increases in freshwater fluxes to the oceans which probably disturbed the ocean s thermohaline circulation and hence global climate4 7 sea level increases bear witness to the melting of continental ice sheets but only two such records from barbados8 9 and new guinea10 11 corals have been accurately dated but these corals overlie active subduction zones where tectonic movements are large and often discontinuous especially in new guinea so the apparent sea level records may be contaminated by a complex tectonic component here we date fossil corals from tahiti which is far from plate boundaries and thus is likely to be tectonically relatively stable and remote from the locations of large former ice sheets the resulting record indicates a large sea level jump shortly before 13 800 calendar years bp which corresponds to meltwater pulse 1a in the barbados coral records8 9 the timing of this event is more accurately constrained in the tahiti record revealing that the meltwater pulse coincides with a short and intense climate cooling event12 15 that followed the initiation of the bolling allerod warm period12 16 but preceded the younger dryas cold event by about 1 000 years

early cenozoic two phase extension and late cenozoic thermal subsidence and inversion of the bohai basin northern china abstract the bohai basin is one of a family of early cenozoic extensional basins that lie along the eastern margin of asia from russia to vietnam initial extension was probably triggered by subduction roll back of the oceanic pacific plate from the asian continent there were two phases in the bohai basin s rift history the earlier paleocene early eocene phase resulted in the deposition of the kongdian formation and the fourth lowest member of the shahejie formation in a series of elongate half grabens these half grabens have master faults with a nne ssw orientation secondary normal faults are typically clockwise oblique to the master faults indicating a component of dextral transtension deposition was focused in the west and south of the present basin these rocks are mainly alluvial fan and fluvial red beds the architecture of the basin underwent an important change at ca 43 45 ma middle eocene beginning with the deposition of the third member of the shahejie formation in part these sediments were deposited in the same half grabens as the kongdian formation but the bozhong depression in the central part of the basin originated at this time and became the major depocentre the bozhong depression superficially resembles a pull apart basin it formed when continued transtension of the earlier tertiary fault systems to the east and west created an extensional overlap between them during this phase the basin as a whole had a geometry with elements typical of both pull apart and transtensional basins regional extension in many east asian basins ended at the end of the oligocene probably because of the onset of transpression within eastern asia caused by the collision of australia with the philippine sea plate dextral transpression caused minor inversion of some of the earlier normal faults in bohai but as a whole the basin began to subside in a post rift phase of thermal subsidence that has lasted until the present day

sedimentary evidence against large strike slip translation on the northern altyn tagh fault nw china abstract whether the oblique left reverse northern altyn tagh fault has large cumulative offset 120 km is one of the most controversial issues concerning the deformation mechanics for the northern tibetan plateau in order to obtain material constraints on its total displacement sedimentologic and bedrock provenance analysis of oligocene pleistocene strata on the northern side of the fault was conducted lithofacies analysis and 970 paleocurrent measurements show that these strata were products of fluvial systems originating from south of the fault making it possible to constrain the fault s slip history by establishing cross fault sediment source linkages identification of 5217 conglomerate clasts in the field indicates that major clast types are quartzite 30 50 schist gneiss increasing upsection from 10 to 40 50 and marble decreasing upsection from 20 30 to 30 km strike slip translation on the northern altyn tagh fault and support the model that strain induced by indian indentation has been partitioned into left slip on the altyn tagh fault and reverse dip slip on the northern altyn tagh fault

seismic characteristics and identification of negative flower structures positive flower structures and positive structural inversion negative and positive flower structures and positive inverted structures imply specific modes of formation and their distinctive characteristics make them important criteria for the identification of certain structural styles a negative flower structure from the andaman sea consists of a shallow synform bounded by upward spreading strands of a wrench fault that have mostly normal separations paralleling monoclines and oblique en echelon normal faults flank the divergent wrench fault a positive flower structure from the ardmore basin oklahoma consists of a shallow antiform displaced by the upward diverging strands of a wrench fault that have mostly reverse separations en echelon folds are present on either side of this convergent wrench fault flower structures may resemble extensional or contractional fault blocks on individual seismic profiles flower structures are identified by their unique internal fault and fold architecture by their association with a straight and throughgoing zone of deformation and by their lack of a consistent sense of separation or regional upthrown side positive structural inversion at the rambutan oil field south sumatra basin has formed a shallow anticlinorium and has partly uplifted the underlying graben deeper fault segments bounding the graben have retained their normal fault profiles but at shallow levels some of these faults have reverse separations similar changes of separation with depth may be produced by strike slip but sets of faults with listric profiles and nearby blocklike trend patterns identify the inversion as a dip slip event where correlation of reflections is uncertain or deep control is unobtainable positive inverted structures may also resemble contrational fault blocks detached normal fault assemblages and certain negative inverted structures

deep sea benthic foraminiferal recolonisation following a volcaniclastic event in the lower campanian of the scaglia rossa formation umbria marche basin central italy we studied the distribution of deep water agglutinated foraminiferal dwaf assemblages across a 15 cm thick volcaniclastic layer in the lower campanian scaglia rossa limestones of the umbria marche basin above the volcaniclastic layer which is devoid of foraminifera a remarkable pattern of recovery among dwaf has been observed the complete recovery of dwaf in terms of trophic groups and complexity of assemblages is observed in the first 5 cm above the volcaniclastic layer representing 4 8 kyr based upon the mean sedimentation rate of the campanian scaglia rossa formation in its initial stage the recovery pattern is remarkably similar to that observed following the 15 june 1991 mount pinatubo ashfall in the abyssal south china sea where various species of reophax a small organically cemented species of textularia and the calcareous species quinqueloculina seminula and bolivina difformis are the earliest recolonisers on top of the tephra layer such similarities between modern and fossil analogues strengthens the reliability of environmental reconstructions based on dwaf fl 2002 elsevier science b v all rights reserved

tectonic control for evaporite formation in wuyang sag southern north china basin abstract there is a wide distribution of thick evaporites in the he21 and he1 members of the wuyang sag southern north china basin based on drilling data previous researchers have analyzed the formation mechanism of evaporites in wuyang sag and considered that their origination stems from the insufficient provenance and dry climate of the area however other researchers have suggested that the qinling dabie mountains on the southern part of wuyang sag acted as a stable source material throughout the deposition period of the sag these contrasting hypotheses indicate that further investigation is needed to clearly identify the evaporite genesis mechanism in wuyang sag using both seismic and geologic data this paper analyzes the impact of the uplift structure of the wuyan sag area on evaporite formation this analysis is based on restoration of the southern boundary of the sag in the deposition period with respect to the largest strike slip fault taking the erosion of the lower tertiary strata at the southern boundary of the sag greatest tectonic activity as the starting point of this study and the movement of the nw strike slip fault at the eastern part of the sag the following conclusions were drawn 1 the end stage of deposition of the he22 member of the hetaoyuan formation was an important period in the base level transition for the wuyang sag during the depositional period from the he3 member to the he22 member the sag gradually expanded as the base level was rising in the depositional period from the he21 member to the he1 member the sag gradually shrank and the base level was lowered due to the influence of structural uplift in the meantime inside the sag the left lateral strike slip fault at the basement became active again and caused the eastern area of the strike slip fault to be uplifted in the depositional period from the he21 member to deposition of the liaozhuang formation 2 the structure uplift during the depositional period from the he3 member to the he22 member blocked part of the provenance to infill the wuyang sag therefore this activity resulted the sag becoming closed or semi closed leading to the deposition of evaporites

identification of wrench faults using subsurface structural data criteria and pitfalls 1 many structures imaged with reflection seismic can resemble a wrench fault system because of the great structural diversity of strike slip faults and the wide range of contractional and extensional features associated with these faults because of these resemblances numerous faults are misidentified as wrench faults by workers using subsurface structural data credible identification requires combinations of profile and map criteria 1 narrow long straight throughgoing solitary master fault or zone of deformation 2 steep to moderate dip of the master fault at depth 3 offset of the top of basement 4 changes in relative upthrown side separation sense and or fault dip direction at depth or along the strike of the master fault 5 narrow fault slices within the master fault zone that steepen and join at depth negative and positive flower structures 6 different separation sense and orientation of relative upthrown side at these fault slices and 7 coeval en echelon flanking structures the identification should be confirmed with other criteria that refute alternative interpretations the main pitfalls to a reliable identification are not considering alternative structural styles and the misinterpretation of features or patterns that superficially resemble wrench systems the profile geometries of basement involved reverse or normal faults particularly those with structural inversion can resemble the single strand of convergent or divergent wrench faults profile geometries of flower structures can be mimicked by narrow contractional horsts or narrow extensional grabens complexly faulted anticlines or synclines splay faults fault zones intruded by salt or shale and overprinted structures pitfalls in interpreting map relationships are possible when structural patterns combine several tectonic influences are controlled by rock anisotropy or include elements hat are not coeval and if the patterns characteristic of other styles are misinterpreted many erroneous identifications of wrench faults can be eliminated by demonstrating that the investigated fault or feature lacks a straight trace lateral length or throughgoing continuity

continuous 150 k y monsoon record from lake eyre australia insolation forcing implications and unexpected holocene failure our reconstructed history of lake eyre provides the first continuous continental proxy record of australian monsoon intensity over the past 150 k y this continental record s broad correspondence to the marine isotope record demonstrates that this very large catchment with its hydrology dependent on a planetary scale climate element responds to milankovitch scale climate forcing abrupt transitions from dry phases to wet phases ca 125 and 12 ka coincide with northern hemisphere winter insolation minima rather than southern hemisphere summer insolation maxima indicating that northern hemi sphere insolation exerts a dominant control over the intensity of the australian monsoon stratigraphic and dating uncertainties of other wet phases preclude conclusive correlation to specific insolation signals but within the uncertainties are consistent with northern hemisphere forcing regardless of the hemispheric forcing the low intensity of the early holocene australian monsoon by comparison with the last interglacial and particularly the last high level lacustrine event at 65 60 ka when all forcing elements were modest is an enigma that can be explained by a change in boundary conditions within australia

climates of the last three interglacials in subtropical eastern australia inferred from wetland sediment geochemistry abstract records of australian climate during marine isotope stages 5 and 7 130 71 and 243 191 ka are rare preventing detailed assessments of long term climate drivers and ecological responses across the continent over glacial interglacial timescales this study presents a geochemistry based palaeoclimate record from fern gully lagoon on north stradbroke island also known as minjerribah in subtropical eastern australia which records climates in mis 7a c mis 5 and much of the holocene in addition to mis 4 71 57 ka and parts of mis 6 mis 3 and mis 2 191 130 57 29 and 29 14 ka indicators of inorganic sedimentation from a 9 5 m sediment core focussed on high resolution estimates of sediment geochemistry supported by x radiography inorganic content and magnetic susceptibility were combined with a chronology consisting of six radiocarbon 14c and thirteen single grain optically stimulated luminescence osl ages hiatuses occurred at 178 153 ka 36 21 ka and 7 2 ka and likely result from the wetland drying low values of locally sourced aeolian materials indicate a wet mis 7a c and early mis 6 before a relatively dry mis 5 inorganic flux during the holocene was up to four times greater than during mis 5 consistent with long term interglacial drying observed in other regions most notably in central australia this study highlights the importance of employing a combination of multiple dating approaches and calibrated geochemical proxies to derive climate reconstructions and to identify depositional complexities in organic rich wetland records

physical analog modeling of pull apart basin evolution abstract pull apart basins are structural depressions formed by localized extension along strike slip fault systems typically at releasing bends or steps in the fundamental strike slip system analog modeling is used to evaluate the sequence of structural evolution of pull apart basins and factors that control their degree of structural asymmetry and geometry basin evolution internal structure and overall symmetry are investigated for oblique releasing step angles and with varying rates of displacement between brittle and ductile crust on opposing sides of the strike slip system while maintaining relative rates between brittle crust on opposing sides of the basin pull apart basin evolution is separated into three stages incipient early and mature incipient pull apart basins are characterized by formation of a normal fault bounded graben or half graben parallel to the oblique step between main strike slip zones in the early stage of formation additional normal faults form toward the basin interior from the original bounding faults and cross basin strike slip faults cut diagonally across the basin interior basin bounding normal fault systems are characterized by lateral variations of fault throw and localized relay ramps in the mature stage of evolution strike slip and normal faults join to completely bound the pull apart basin analog model results indicate that displacement associated with cross basin faults causes development of a through going strike slip fault that links the two main strike slip displacement zones ultimately resulting in a decline in normal fault activity asymmetric symmetric and hybrid pull apart basins all follow the same overall deformation sequence just described the asymmetry of a pull apart basin is controlled by the degree of decoupling between brittle and ductile crust beneath the two crustal blocks in relative motion this is modeled by maintaining a constant relative rate of motion between opposing fault blocks in all models but varying the rate between the blocks and the fixed model basement absolute rate models in which one side of the detachment is fixed with respect to the basement form asymmetric pull apart basins defined by a half graben with the master fault on the mobile side in models where opposing sides of the fault system are equally decoupled from the basement symmetrical pull apart basins form defined by horst and graben structures and master fault dominance switching sides along the length of the basin fault segmentation associated with relatively immature pull apart basins may be capable of arresting earthquake rupture late linkage of main strike slip zones by a cross basin fault could extend potential rupture area dramatically increasing the possibility for large magnitude earthquakes

analog modeling of pull apart basins scaled sandbox models have successfully simulated the geometries and progressive evolution of pull apart basins developed in a weak sedimentary cover above right stepping releasing dextral strike slip fault systems in rigid basement synkinematic basin infill was added progressively as the models were deformed vertical and horizontal sectioning of the completed models has allowed the full three dimensional architecture of the pull apart system to be analyzed we present three representative end member experiments 30 underlapping releasing sidestep 90 sharp nonoverlapping releasing sidestep and 150 overlapping releasing sidestep the pull apart basin geometries are typically sigmoidal to rhombic grabens the geometries of which are dependent upon the architecture of the underlying basement fault systems underlapping releasing sidestepping faults offset angles of 30 75 typically form elongate rhomboidal grabens 90 releasing offset sidesteps produce shorter squat rhomboid pull apart basins and overlapping releasing sidesteps 115 150 produce box like grabens with highly kinked basin sidewalls the pull apart basins are bounded by terraced oblique slip extensional sidewall fault systems that link the laterally offset principal displacement zones pdz of the main dextral strike slip faults the sidewall faults show changes in kinematics from dominantly dip slip extension in copyright 1997 the american association of petroleum geologists all rights reserved 1manuscript received june 24 1996 revised manuscript received november 20 1996 final acceptance june 10 1997 2fault dynamics project geology department royal holloway university of london egham surrey tw20 oex united kingdom supported by the fault dynamics project sponsored by arco british limited petrobras u k ltd bp exploration conoco u k limited mobil north sea limited and sun oil britain we also acknowledge additional funding from sun oil britain landsat thematic mapper data courtesy of rtz mining and exploration limited south american division jurrian reijs is thanked for field data relating to the salina del fraile pull apart basin chris elders is thanked for reviewing earlier versions of this manuscript and j crowell c morley and k biddle are thanked for constructive reviews of the manuscript the contents of this paper have been

a reconstruction of extratropical indo pacific sea level pressure patterns during the medieval climate anomaly subtropical and extratropical proxy records of wind field sea level pressure slp temperature and hydrological anomalies from south africa australia new zealand patagonian south america and antarctica were used to reconstruct the indo pacific extratropical southern hemisphere sea level pressure anomaly slpa fields for the medieval climate anomaly mca 700 1350 ce and transition to the little ice age lia 1350 1450 ce the multivariate array of proxy data were simultaneously evaluated against global climate model output in order to identify climate state analogues that are most consistent with the majority of proxy data the mean slp and slp anomaly patterns derived from these analogues illustrate the evolution of low frequency changes in the extratropics the indo pacific extratropical mean climate state was dominated by a strong tropical interaction with antarctica emanating from 1 the eastern indian and south west pacific regions prior to 1100 ce then 2 the eastern pacific evolving to the central pacific la nina like pattern interacting with a ve sam to 1300 ce a relatively abrupt shift to ve sam and the central pacific el nino like pattern occurred at 1300 a poleward equatorward shift in the subtropical ridge occurred during the mca mca lia transition the hadley cell expansion in the australian and southwest pacific region together with the poleward shift of the zonal westerlies is contemporaneous with previously reported hadley cell expansion in the north pacific and atlantic regions and suggests that bipolar climate symmetry was a feature of the mca

late quaternary milankovitch scale climatic change and variability and its impact on monsoonal australasia four pollen and charcoal records derived from marine cores around the northern perimeter of australia are examined to provide a regional picture of patterns causes and impacts of climate change over the last 100 300 ka the availability of radiocarbon dates and oxygen isotope records for the cores provides primary chronological control spectral analysis of components of these records demonstrates an overall importance of milankovitch frequencies with clear glacial interglacial cyclicity dominated by variation in precipitation in addition a number of pollen taxa as well as charcoal particles exhibit a 30 ka frequency that is considered from its relationship with biomass burning and with results of past modelling to reflect changes in the intensity of el nino southern oscillation enso variability pollen components of all records show a decline frequently stepwise in more fire sensitive vegetation and its replacement with more fire tolerant vegetation there is some evidence that this trend is linked to an onset or general increase in enso activity and perhaps also to variation in monsoon activity dating from about 300 ka bp that was caused by changes to oceanic circulation within the indonesian region the trend may have accelerated within the last 45 ka due to burning by indigenous people c 2003 elsevier b v all rights reserved

structural and sedimentary characteristics of the liangjia wangchang strike slip region yitong basin china abstract the yitong basin a typical strike slip basin is part of the northern segment of the world famous tanlu strike slip fault area in china research is needed to understand how the strike slip tectonic environment affects the development of structures and depositional systems within the basin the aim of this paper is to analyze how the right lateral strike slip movement of the northwestern boundary faults in this region controls extensional faulting and to analyze differences in two main sedimentary sequences termed sysq1 and sysq2 that result from strike slip movement the study is based on geological and geophysical data the following conclusions are drawn 1 the two periods of strike slip movement of the boundary fault generated two episodes of extensional fault inside the basin the extensional faults have a characteristically episodic activity related to the episodic strike slip movement the extensional faults have small fault throw and their activity lags behind the strike slip movement of the northwestern boundary faults 2 the strike slip movement of the boundary faults generated the extensional faults inside the basin and changed the locus of depocenters with complimentary changes in the paleogeomorphology and in the distribution of depositional facies it is this strike slip movement that caused the differences in sedimentary and structural characteristics between sequences sysq1 and sysq2

aridity in australia pleistocene records of palaeohydrological and palaeoecological change from the perched lake sediments of fraser island queensland australia abstract a quaternary sedimentary sequence ca 600 ka from a perched lake old lake coomboo depression on the world heritage listed coastal sandmass of fraser island has been analysed for dry bulk density carbonised particles pollen and chemistry a chronology has been constructed for the organic sediments using a combination of radiocarbon and uranium thorium disequilibrium analysis the lake basin is small ca 9 ha with a restricted groundwater catchment delimited by an aquitard and minimal surface runoff it therefore acts as a sensitive raingauge with the perched groundwater table and hence the sediment facies deposited within the lake reacting sensitively to any changes in the water budget the sequence passes through a series of glacial cycles demonstrating hydrologic and vegetation change the record indicates a long term three stage fall in the water table from lake full ca 600 ka to an ephemeral lake in the holocene paralleled by a shift in the vegetation composition from predominantly rainforest to sclerophyllous components the evidence for fire is minimal at the beginning of the record increases from 350 ka through the sequence culminating at or before the lgm is low during the lgm and is relatively high during the holocene succession fire and climatic change along with the accumulative effect of a series of 100 ka cycles are believed to have driven the hydrologic and vegetation change and a human factor is not required to explain the record within the overall long term increase in aridity recorded through about six glacial cycles there appears to be a variation in the dryness signal of glacial maxima suggesting some form of supercycle phenomenon this record complements and extends the information available from some of the oldest pollen analysed quaternary lake sequences in australasia such as lynch s crater in the atherton tableland of north queensland and lake george in the southern tablelands of new south wales and from some of the most sensitive lacustrine fluvial sedimentary records in the lake eyre basin signals for major environmental changes recorded in deep sea cores and the loess deposits of china may also be represented in the record the implications of the depression record if further corroborated are significant in relation to climatic modelling rainforest survival and faunal extinction

a late pleistocene and holocene vegetation and environmental record from lake wangoom western plains of victoria australia abstract pollen microfaunal and sedimentological evidence from the top 20 m of sediment in a closed volcanic crater lake is used to construct a detailed record of vegetation and environmental conditions through the holocene and a substantial part of the late pleistocene radiocarbon dating suggests that the sequence covers tha last 51 000 yr or so high lake levels and the presence of forest or woodland vegetation indicate that the holocene and the basal few thousand years of the record experienced wet and warm conditions the earliest period was succeeded by a long phase of lower but variable moisture levels before more arid conditions resulted in the replacement of forest and woodland by herbaceous vegetation and frequent lake drying periods of slight amelioration occurred between about 27 000 and 19 000 and before 15 000 radiocarbon yr ago maximum aridity occurred between about 19 000 and 10 000 yr b p a period incorporating the height of the last glacial during the pleistocene the lake became gradually more saline but has been fresh during the holocene even under low lake levels an increase in charcoal values is recorded probably around 20 000 years ago and this could have resulted from increased burning as a result of the activities of aboriginal people this may have also caused a change in understorey vegetation from one composed largely of asteraceae to grassland the record is compared with others from southeastern australia and there is good correspondence through the last 20 000 or 30 000 yr but before this problems of dating and the condensed nature of most sequences prevent detailed correlation

late holocene cliff top blowout activation and evolution in the cooloola sand mass south east queensland australia cliff top dunes are a locally important geomorphic features of sedimentary coasts they are traditionally interpreted as being sourced by or with sand derived from the beach below the cliff this paper presents the results of a stratigraphic and geochronological study of carlo sand blow a coastal blowout that has developed on top of a high sandy cliff in the cooloola sand mass south east queensland we use a combination of sedimentological pedological and geophysical techniques along with optically stimulated luminescence dating to determine the depositional history and evolution of the blowout we demonstrate that the blowout is dominantly nourished by sand eroded from its floor rather than the adjacent beach the original dune surface dates to the first half of the last glacial period c 40 70 ka and this dune was deflated in the late holocene dune activity is directly associated with cliff undercutting because of coastal retreat in the late holocene but coastal erosion on its own is not capable of maintaining aeolian activity blowout activity occurred between 2 6 and 2 3 ka and again at 0 3 ka with aeolian sand burying palaeosols both soil surfaces contained charcoal and tree stumps in growth position and our study suggests that fire is the immediate trigger for blowout reactivation it is likely that these fires were anthropogenic in origin because the site is somewhat protected from natural fire and the ages coincide with intensification of human use of coastal sites in the area

structural and stratigraphical constraints on the kinematics history of the southern tan lu fault zone during the mesozoic anhui province china abstract the tan lu fault zone tlfz extends in a nne ssw direction for more than 2000 km in eastern china it has been considered either as a major sinistral strike slip fault as a suture zone or as a normal fault we have conducted a structural analysis of the southern segment of this fault zone stlfz in the anhui province the ages triassic to palaeocene of the formations affected by the faults have been re appraised taking into account recent stratigraphical studies to better constraint the ages of the successive stages of the kinematics of the stlfz subsequently the kinematics of the faults is presented in terms of strain stress fields by inversion of the striated fault set data finally the data are discussed in the light of the results obtained by previous workers we propose the following history of the stlfz kinematics during the mesozoic at the time of collision a nne orientated tan lu margin probably connected two margins located north of the dabie and sulu collision belts during the middle late triassic the scb has been obliquely subducted below the ncb along this margin which has acted as a compressional transfer zone between the dabie and sulu continental subduction zones the stlfz has been initiated during the early jurassic and has acted as a sinistral transform fault during the jurassic following which the ncb scb collision stopped a nw trending extension related to metamorphic domes was active during the basal early cretaceous 135 130 ma it has been followed by a nw se compression and a ne sw tension during the middle late early cretaceous 127 to 105 ma possibly 95 ma at that time the tlfz was a sinistral transcurrent fault within the eastern part of the asian continent during the late cretaceous palaeocene the stlfz was a normal fault zone under a wnw ese tension

extensional fault arrays in strike slip and transtension abstract sedimentary basins developed under conditions of strike slip or transtension are subject to significant rotational strains yet faults developed in such regimes are commonly explained using simplified models that ignore rotation the heaves of extensional faults developed provide a means of quantifying this rotation for ideal strike slip simple shear the apparent stretch due to fault heaves can be related simply to shear strain at shear strains above 1 0 previously formed extensional faults begin to show inversion as reverse faults becoming fully inverted at 2 0 in transtensional basins the apparent stretch is related in addition to the initial orientation of the faults which may itself be related to the incremental strain in the stellarton basin of nova scotia canada fault heaves and orientations can be measured from subsurface mine plans measurements of these quantities indicate that strain was only mildly transtensional with a small the measurement of fault heaves potentially provides detailed information on strain wherever strike slip or transtensional basins have been explored in detail by seismic or other subsurface methods

the structural and tectonic relationships of the major fault systems of the tan lu fault zone with a focus on the segments within the north china region abstract the jiashan lujiang yishu and bohai segments have been the most tectonically active parts of the tan lu fault system since the mesozoic any analysis of faulting processes in the tan lu system is highly dependent on the relationships among the three segments here we divide the tan lu system into three styles of faulting strike slip faulting regional extensional faulting and listric normal faulting on the basis of emap data seismic profiles and geological evidence we suggest that 1 the strike slip faults which formed in the late jurassic include mainly the jiashan lujiang fault the deep parts of the chihe taihu fault and the guhe sanbing fault these three faults have had the most dramatic effect on the jiashan lujiang segment the strike slip style of faulting produced a huge positive flower structure that extends between the deep section of the chihe taihu fault and the guhe sanbing fault and overlaps with the position of the zhangbaling ductile shear zone 2 the regional extensional style of faulting whose characteristics are reflected best in the yishu fault zone is composed of the changyi dadian anqiu quxian yishui yangtou and tangwu gegou faults all of which were active during the early cretaceous these extension dominated faults extend southwards to the jiashan and hefei basins and die out in front of the dabie mountains to the north the faults penetrate the deeper parts of the weibei depression where they controlled cretaceous deposition in graben horst graben structures 3 the listric normal faults which were initiated in the paleogene generally occur around the bohai bay basin and include a series of ne trending faults in the weibei depression such as the tandong and tanxi faults these listric faults differ from the regional extensional faults in their localized occurrence and association with basin formation our study indicates that these three styles of faulting varied not only in timing and mechanical properties but developed at different levels at different locations resulting in different tectonic relationships and the formation of different geologic features in the different segments of the tan lu master system

a 25 000 year record of environmental change from welsby lagoon north stradbroke island in the australian subtropics there are few continuous australian palaeoclimate records that extend beyond the last glacial maximum lgm meaning that knowledge of regional climates before during and after this period is limited understanding late pleistocene climates of the subtropics is important because of the fundamental role the region plays in the large scale global transfer of energy from low latitudes palaeoclimate studies of subtropical regions can help define the extent of warming cooling during the large global climatic events which characterise the late pleistocene here we report the results from a multi proxy analysis of a sediment record from welsby lagoon on north stradbroke island in the eastern australian subtropics spanning the past ca 25 000 years stable c and n isotope analysis and high resolution contiguous records of macrocharcoal deposition and sediment organic content are interpreted in conjunction with a previously published pollen record sediment organic content displayed a very strong correlation with total organic carbon toc content as determined through elemental analysis and given the peaty nature of the sediment is interpreted as indicative of moisture balance the proxies reflect wet subtropical climates in the lead up to the lgm which led to an expansion of the wetland this was followed by a cool dry and windy lgm ca 22 3 19 7 000 years before present kyr bp which was punctuated by a brief wet phase ca 21 7 20 4 kyr bp a salient feature of the deglacial period is a rapid increase in toc around 15 kyr bp coincident with the antarctic cold reversal and bolling allerod warm phase increased fire frequency is evident in the holocene which is characterised by otherwise stable climate and vegetation this study supports the notion of variable climates during the lgm and finds an onset of deglacial warming in the australian subtropics that predates the holocene

sedimentary records of rift to pull apart tectonics in the miocene eoil basin se korea the miocene eoil basin se korea is a pull apart basin formed by dextral crustal deformation during the backarc opening of the east sea the gampo conglomerate the lowermost formation of the basin provides significant information on how a pull apart basin initiates and is filled by sedimentary strata the formation consists of nonmarine conglomerates sandstones mudstones and a variety of volcaniclastic deposits that were deposited in alluvial fans delta slopes braided streams mouth bars and lakes these deposits are organized into several stratal packages sp with contrasting geometries sp i at the base consists of mouth bar to delta front and volcaniclastic deposits and shows rapid facies variations along the southeastern normal fault margins sp i suggests that the early basin was bounded by multiple incipiently developed normal faults with variable displacement and accommodation creation sp ii consists of thick alluvial fan conglomerates and overlies sp i abruptly suggesting sudden input of coarse grained sediment from the uplifted footwalls it is thickest near the central part of the southeastern normal fault margins suggesting development of a large alluvial fan near a transfer zone sp iii consists mostly of mouth bar sandstones indicating abrupt subsidence of the basin and the transition from subaerial to subaqueous environments sp iv consists of braided stream conglomerates suggesting gradual progradation of coarse grained fluvial systems toward the basin when the extension and subsidence of the basin was slowed sp v shows upward deepening facies changes from braided stream to mouth bar deposits suggesting resumption of basin subsidence notably the cumulative thickness of sp iii to sp v is thickest near the northeastern and southwestern strike slip margins suggesting migration of the loci of maximum subsidence from the normal fault margins towards the strike slip margins after deposition of sp ii the change in stratal architecture suggests that the activity of the normal faults was dominant in the early stage of the basin evolution whereas the activity of the strike slip faults became more pronounced afterwards overall the stratal architecture of the gampo conglomerate appears to record the transition tectonics from rift to pull apart during the incipient stage of a pull apart basin development the eoil basin is thus interpreted to have been hybrid in nature influenced by the dynamic changes of the basin margin faults which were either normal or strike slip

structural architecture and tectonic evolution of the fangzheng sedimentary basin ne china and implications for the kinematics of the tan lu fault zone abstract the 100 km long ne sw trending fangzheng sedimentary basin is one of a series of cenozoic petroliferous depocenters along the tan lu fault zone tlfz in ne china it is delimited by the nw and se boundary faults and dissected by the basin parallel central fault all of which are part of the dextral tlfz displaying releasing and restraining bends along strike the basinal strata and its pre cenozoic basement show well developed transtensional and transpressional structures in these domains the stratigraphy in the basin consists of 5000 m thick fine to coarse grained clastic rocks and represents shallow to deep lacustrine fan delta beach bar and fluvial fluvial delta depositional settings the paleocene eocene rock units 1500 m rest along an unconformity on a mesozoic granitic basement and appear to have been accumulated in local depocenters in the hanging walls of the oblique normal nw and se boundary faults the oligocene baoquanling formation 3200 m overlies these paleogene units along a regional unconformity which indicates a period of uplift and non deposition caused by basin wide contraction in the latest eocene an abrupt increase in the stratigraphic thickness of the baoquanling formation particularly its middle oligocene second member with extensive and thick mudstone deposits suggests the development of increased accommodation space in a lacustrine environment within the fangzhen basin this event was coeval with the timing of rejuvenated intra basinal rifting caused by transtensional deformation along the central and se boundary faults oblique rifting along and across the basin during the oligocene was accompanied by mafic magmatism which produced hypabyssal diabasic intrusions and sills crosscutting the basinal strata the main mode of deformation in late miocene and younger rock units was strike slip faulting which produced oblique slip normal faults and en echelon folds the fault geometry kinematics and the related stress regime along the dextral tlfz have played a major role in the development of local depocenters including their shape size and depth and significantly affected the formation of source rocks and structural traps in the petroliferous fangzhen basin

holocene palynology of whitehaven swamp whitsunday island queensland and implications for the regional archaeological record palynological study of whitehaven swamp whitsunday island provides the first holocene palaeoenvironmental record for the whitsunday region on the central queensland coast sediment stratigraphy and radiocarbon dating indicate continuous freshwater swamp conditions since around 7000 radiocarbon years before present bp pollen and charcoal analyses provide local and regional vegetation and fire histories for the site and surrounding area varying representation of swamp elements particularly leptocarpus and cyperaceae provides evidence for phases of permanent and ephemeral swamp conditions the regional vegetation record is dominated by rainforest sclerophyll and beach strand elements strongest rainforest representation occurs around the mid holocene while sclerophyll elements increase from the late holocene to present charcoal analyses indicate that fire has been a constant component of the whitsunday environment throughout the period represented negative correlation between high charcoal and leptocarpus pollen concentrations suggests a strong local component to the charcoal record and a history of on site burning during ephemeral swamp phases the vegetation reconstruction suggests moister than present conditions at whitehaven between approximately 7000 to 4500 bp this complies with claims for a mid holocene climatic optimum based on pollen records from the atherton tableland to the north but contrasts with suggested mid holocene aridity based on a surrogate lake water level record from fraser island to the south comparisons with the regional archaeological record provide no evidence for direct links between major environmental change and archaeologically identified cultural change in particular claims for late holocene population intensification are not matched by changes in the charcoal record this may suggest that widespread vegetation burning was not a predominant feature of hunter gatherer strategies that were focused towards marine resources and or that human induced fire regimes were already well entrenched prior to intensification

pleistocene vegetation of the humid tropics of northeastern queensland australia abstract the humid tropics area of northeastern queensland has provided a substantial and detailed history of rainforest and rainforest savanna interactions from the pollen analysis of a number of sites on the volcanic atherton tableland through the latter part of the quaternary period a recent extension of the record to close to the base of the quaternary from examination of an offshore core provides a broad regional and temporal context for evaluation of the true significance of late quaternary changes it is apparent that the major sustained change in the vegetation of the region occurred relatively recently probably within the last 140 000 yr and that this change was time transgressive it involved the replacement of extensive moist rainforest by open eucalypt woodland and is considered to have been most likely caused by the burning activities of aboriginal people some aspects of the record from this region can contribute to the history of rainforest on a global scale but other features of it re inforce the unique nature of the development of australian vegetation patterns

mid to late holocene el nino southern oscillation dynamics reflected in the subtropical terrestrial realm high resolution pollen analysis of mid to late holocene peat deposits from southwest florida reveals a stepwise increase in wetland vegetation that points to an increased precipitation driven fresh water flow during the past 5 000 years the tight coupling between winter precipitation patterns in florida and the strength of the el nino southern oscillation enso strongly suggests that the paleo hydrology record reflects changes in enso intensity a terrestrial subtropical record outside the indo pacific warm pool both documents ecosystem response to the known onset of modern day enso periodicities between 7 000 and 5 000 years b p and subsequent enso intensification after 3 500 years b p the observed increases in wetness are sustained by a gradual rise in relative sea level that prevents a return to drier vegetation through natural succession

alluvial to lacustrine systems in a pull apart margin southwestern eumsung basin cretaceous korea abstract in the pull apart margin of pull apart basins sedimentation patterns are poorly known compared with those in rift basins the rhomb shaped eumsung basin cretaceous mid west korea was formed in an overstep of the kongju fault system and provides significant information on how sedimentary bodies dynamically filled the pull apart margin according to a detailed analysis of sedimentary facies palaeoflow directions clast compositions and downstream changes in clast size the southwestern basin fills comprise three facies associations representing distinctive depositional environments 1 facies association f a i volcaniclastics dominated alluvial fan 2 f a ii alluvial plain and 3 f a iii floodplain lake the matrix supported and clast supported conglomerate f a i is indicative of deposition in alluvial fans the hollow fill or sheetlike deposits encased in purple siltstone f a ii are suggestive of channel or sheetflood deposition in an alluvial plain the dominant purple and green mudstone f a iii indicates deposition in floodplain and lacustrine environments the distribution of facies associations represents a basinward change in depositional environments from alluvial fan to lacustrine systems the succession is divisible into three large scale lateral and partly vertical units the southernmost ochang 1 5 km thick the medial baeti 1 km thick and the northernmost kugokri units 0 5 km thick on the basis of basinal structure and changes in clast composition and lithofacies the ochang baeti transition reflects synchronous development of the alluvial to lacustrine systems in a pull apart margin this succession development is attributable to the basinal faults progressed during the basin development the baeti kugokri transition recorded the changes in clast composition and lithofacies which was due to the progressive shifting in basinal setting from a pull apart margin to a strike slip margin unlike that of the strike slip margins clast composition of the pull apart marginal fills reflects adjacent source rock lithology in the pull apart margin alluvial to lacustrine systems show a transverse to margin channel network 060 135 converging into the southwestern depocentre although the basin is of strike slip origin sedimentation patterns in the pull apart margin are suggestive of relatively synchronous developments of the alluvial to lacustrine systems reflecting the lithology of the adjacent source rock and subsurface structure of normal slip dominant faults

progressive changes in sedimentary facies and stratal patterns along the strike slip margin northeastern jinan basin cretaceous southwest korea implications for differential subsidence abstract in strike slip basins proximal stratal patterns are a function of displacement on basin bounding faults in order to better understand factors that control changes in sedimentary facies and stratal patterns of the northeastern part of the jinan basin cretaceous a strike slip basin we made a detailed analysis of sedimentary facies depositional architecture and paleoflows the sedimentary successions can be grouped into five facies associations representing five depositional environments 1 facies association fa i alluvial fan 2 fa ii small scale gilbert type delta 3 fa iii large scale steep delta slope 4 fa iv base of large scale steep delta slope and prodelta and 5 fa v lacustrine plain the successions are divided into two distinct sedimentary fills on the basis of facies associations depositional architecture and paleocurrents 1 marginal fill and 2 longitudinal fill the marginal fill ca 3 2 km thick is present along the strike slip basin bounding fault the lower part of the marginal fill ca 1 3 km thick consists of alluvial fan deposits fa i along the bounding fault which are transitional northward to small scale gilbert type delta fa ii and lacustrine plain fa v deposits the upper part of the marginal fill ca 1 9 km thick contains large scale steep delta slope fa iii and base of delta slope prodelta fa iv deposits accompanied with a northward change in facies associations in the marginal fill the successive alluvial fan small scale gilbert type delta and large scale steep delta prodelta deposits are overlapped shingled northeastward the longitudinal fill ca 2 km thick is characterized by eastward overlapped stacks of large scale steep delta slope fa iii and base of delta slope prodelta fa iv deposits with a westward progradation the longitudinal fill was overstepped by the marginal fill the northeastward shingled geometry of the marginal fill was most likely caused by sinistral strike slip displacements on the basin bounding fault the slightly oblique northward progradation of the marginal fill was due to the northward basin floor tilting in the marginal fill the progressive changes in facies and depositional architecture from the lower alluvial fan small scale gilbert type delta to the upper large scale steep delta prodelta are suggestive of increase in basin subsidence along the strike slip basin margin that was closely related to the variation in displacement on the basin bounding fault the sinistral strike slip movements on the bounding fault also caused the eastward overlapping of the longitudinal fill

post glacial evolution of the indo pacific warm pool and el nino southern oscillation recent research has revealed new insights into the temperature size and variability of the indo pacific warm pool ipwp and the nature of the el nino southern oscillation enso since the last glacial maximum lgm sea surface temperature sst reconstructions from foraminiferal mg ca alkenone and revised coral sr ca palaeothermometry agree that ssts in the ipwp during the lgm were similar to 3degreesc cooler than at present in the central portion of the ipwf the rapid post glacial rise in sst led the deglaciation by similar to 3000 years to produce near modern ssts by the early holocene in contrast further west and north post glacial shifts in ssts in the south china and sulu seas are synchronous with abrupt climate changes in the north atlantic new evidence for the nature of the little ice age in the tropics has been obtained from a 420 year record of coral sr ca and 6180 from the great barrier reef australia this indicates that ssts and salinity were higher in the 18th century than in the 20th century the results suggest that the tropical pacific played a role as a source region of water vapour during the global expansion of little ice age glaciers the onset of modern enso periodicities is identified by palaeo enso records throughout the tropical pacific region similar to 5000 years ago with an abrupt increase in enso magnitude similar to 3000 years ago individual enso events recorded by corals reveal that the precipitation response to el nino temperature anomalies was subdued in the mid holocene the apparent non linear onset of enso in the late holocene appears to reflect abruptly enhanced interaction between the southern oscillation and the pacific intertropical convergence zone comparisons of precipitation variability recorded by great barrier reef corals with enso indices for the last 350 years confirms that non stationarity of enso teleconnections is a natural characteristic of modern climate c 2003 elsevier ltd and inqua all rights reserved

the last glacial cycle from the humid tropics of northeastern australia comparison of a terrestrial and a marine record a detailed pollen record from the ocean drilling program site 820 core located on the upper part of the continental slope off the coast of northeast queensland was constructed to compare with the existing pollen record from lynch s crater on the adjacent atherton tableland and allow the production of a regional picture of vegetation and environmental change through the last glacial cycle some broad similarities in patterns of vegetation change are revealed despite the differences between sites and their pollen catchments which can be related largely to global climate and sea level changes the original estimated time scale of the lynch s crater record is largely confirmed from comparison with the more thoroughly dated odp record conversely the lynch s crater pollen record has assisted in dating problematic parts of the odp record in contrast to lynch s crater which reveals a sharp and sustained reduction in drier araucarian forest around 38 000 yrs bp considered to have been the result of burning by aboriginal people the odp record indicates most likely a stepwise reduction dating from 140 000 yrs bp or beyond the earliest reduction shows lack of a clear connection between araucaria decline and increased burning and suggests that people may not have been involved at this stage however a further decline in araucarian forest possibly around 45 000 yrs bp which has a more substantial environmental impact and is not related to a time of major climate change is likely at least partially the result of human burning the suggestion from the odp core oxygen isotope record of a regional sea surface temperature increase of around 4 degrees c between about 400 000 and 250 000 yrs bp may have had some influence on the overall decline in araucaria and its replacement by sclerophyll vegetation c 2000 elsevier science b v all rights reserved