core evidence of paleoseismic events in paleogene deposits of the shulu sag in the bohai bay basin east china and their petroleum geologic significance abstract the shulu sag located in the southwestern corner of the jizhong depression bohai bay basin of east china is a ne sw trending elongate cenozoic half graben basin the lowermost part of the third member of the shahejie formation in this basin is characterized by continental rudstone and calcilutite to calcisiltite facies based on core observation and regional geologic analysis seismites are recognized in these lacustrine deposits which include soft sediment deformation structures sedimentary dikes hydraulic shattering diapir structures convolute lamination load flame structures ball and pillow structures loop bedding and subsidence structures synsedimentary faults and seismoturbidites in addition mixed source rudstones consisting of the paleozoic carbonate clasts and in situ calcilutite clasts in the lowermost submember of shahejie 3 appear in the seismites suggesting an earthquake origin a complete representative vertical sequence in the lowermost part of the third member found in well st1h located in the central part of the shulu sag shows from the base to the top underlying undeformed layers synsedimentary faults liquefied carbonate rocks allogenetic seismoturbidites and overlying undeformed layers seismites are widely distributed around this well and there are multiple sets of stacked seismites separated by undeformed sediment the nearby nw trending taijiazhuang fault whose fault growth index is from 1 1 to 1 8 and the nne trending xinhe fault with a fault growth index of 1 3 1 9 may be the source of the instability to create the seismites these deformed sedimentary layers are favorable for the accumulation of oil and gas for example sedimentary dikes can cut through many layers and serve as conduits for fluid migration sedimentary faults and fractures induced by earthquakes can act as oil and gas migration channels or store petroleum products as well seismoturbidites and mixed source rudstones are excellent reservoirs due to their abundant primary or dissolved pores

changes in brachiopod body size prior to the early toarcian jurassic mass extinction abstract herein we analyze the shell length as estimation of the body size of several brachiopod assemblages recorded into the extinction interval prior to the early toarcian mass extinction they were collected from representative localities around the iberian massif spain and portugal presenting different paleoenvironmental conditions the analysis performed has revealed two different trends of spatial and temporal changes in body size 1 mean size decreases in the assemblages following an anticlockwise pattern from iberian to lusitanian basins in relation to the progressive environmental stress caused by shifts on terrigenous input and in depth this diminution results from changes in the relative abundance of bigger or smaller species in each area rather than from miniaturization of the taxa 2 some new evolved or more resilient species show increasing sizes over time along the extinction interval this increase affects both big spiriferinides in the iberian basin and small rhynchonellides and koninckinides in the lusitanian basin and runs in parallel to the drop in diversity and the progressive warming of the sea water in this interval in all the localities this increase in body size has been related to the changes in diversity that could have favored the access to resources for resilient or new evolved species the observed patterns are comparable with those detected in the end permian crisis and might indicate a generalizable response to similar biotic crises

sedimentary facies and evolution in the qiantang river incised valley eastern china abstract this paper deals with the sedimentary facies and evolution of the qiantang river qr estuary and the characteristics and formation of the incised valley sequences and the related shallow biogenic gas reservoir on the basis of analysis of over 500 cores the result shows that since the last glaciation the late quaternary formation of the qr estuary area underwent three stages 1 deep cutting stage 2 rapid filling stage and 3 burial stage the fall of global sea level during the last glacial maximum enhanced the fluvial gradient and river cutting resulting in the formation of the large scale qr and taihu incised valleys with the interfluve being exposed to air on both flanks of the incised valley fluvial terraces at the elevations are present near the present qr estuarine mouth corresponding to 60 70 90 100 and 115 125 m burial depths the valleys were filled rapidly with fluvial sediments during the post glacial period with the rise of sea level the river mouth migrated to landward and backwater and retrogressive aggradation was enhanced the qr and taihu incised valleys are associated with an early filling and transgressive channel infilling sequence formation and a late filling and transgressive floodplain estuary formation subsequently the qr valley was buried under estuarine marine and estuarine sand bar sediments from bottom to top the incised valley successions can be grouped into four sedimentary facies river channel floodplain estuary estuary shallow marine and estuary sand bar the thickness of the river channel infilling deposits is controlled mainly by base level rising backwater retrogressive aggradation and neotectonism further localized thickening took place where deeper scour pools were present in the incised valley or fluvial terraces were formed during the fall of elative sea level during the deposition of the floodplain estuary facies the conditions of sea level rise tidal regime sediment supply and accommodation space were suitable for the development of a tidal ridge system the sand lenses associated with this facies may represent a tidal ridge system in the incised valley at the later stage when the estuarine sand bars were formed the sedimentary conditions were no longer favourable resulting in absence of sand ridge deposits biogenic gas is stored in the floodplain estuary sand lenses of the incised valleys the changjiang river provides the major sediment supply for the qr estuary sand bar and the qr carried sediments constitute only a small portion of the deposits

interstadial records of the last glacial period at pantai remis malaysia two eustatic high sea stands during the last glacial period are recognised at pantai remis these highstands lower than present day sea level are tropical manifestations of the ameliorating interstadial climate during the weichselian devensian wisconsin glaciation in the northern hemisphere the earlier highstand corresponds to a sea level of 14 6 m below mean sea level msl it is interpreted as synchronous with oyxgen isotope stage 5a and is correlated with other known sea level curves in other parts of the world the younger high sea stand dated 55810 1140 to 53870 1400 yr bp indicates sea level of 4 3 m below msl it represents an interstadial equivalent that lasted for at least 2000 yr whereas the earlier interstadial period indicates a minimum duration of twice this amount or very likely even longer as reflected from the thickness of the accumulated deposits the palynological records indicate that during interstadial times climatic stability in the tropics is attained and was sufficiently long for vegetation to thrive and develop the palynofloral constituents of the earlier interstadial phase at pantai remis showed the establishment of vegetation in a coastal setting initiated by pandanus swamp forests simultaneously mangrove swamp flourished in the lower lying parts of the area hence the presence of direct tidal influence is evident both the pandanus and mangrove swamps were succeeded by mixed freshwater swamp forests of a campnosperma calophyllum assemblage subsequently a slightly open and somewhat drier mixed swamp forest prevailed marked by the increase in fern spore representation the later interstadial phase showed shorter vegetation successions which commenced on the landward edge of a mangrove swamp forest the mangrove was successively replaced by strand forest as indicated by domination of casuarina equisetifolia the palynological assemblages in both the interstadial periods indicate similarity to the present day coastal vegetation this implies that during the interstadials the climate in the lowlands of peninsular malaysia and presumably throughout the equatorial region was as that prevailing today 1997 john wiley sons ltd

sedimentary structures tentatively attributed to seismic events abstract fingerprints of earthquakes in the sedimentary record are as yet difficult to identify this is particularly true for failure phenomena dewatering slumping fault graded and turbidite structures that could have been triggered also by other kinds of energy input other promising candidates are strange biostratinomic features convex down stacking of shells current orientation in wave ripple accumulations as well as certain preservational features found in geosynclinal pelagic limestones but in every case verification of the seismic origin is still needed

a raised ois 3 sea level recorded in coastal sediments southern changjiang delta plain china abstract the distribution of marine influenced oxygen isotope stage ois 5 to ois 1 sediments was examined in several late quaternary boreholes from the southern changjiang yangtze delta plain china using different dating methods including osl u series ams 14c and paleomagnetism results demonstrate that coastal and estuarine deposition during ois 5 and ois 3 occurred throughout the study area however holocene transgressive sediments were absent on the taihu block the burial depth of intertidal to subtidal sediment deposited during ois 5e records 30 80 m subsidence caused by sediment compaction and tectonic movement since that time however coastal sediments formed during the late phase of ois 3 were buried to a depth of ca 6 15 m in the taihu lake area while the burial depth increased eastward to ca 45 60 m on the coastal plain this phenomenon combined with the distribution of holocene marine strata indicates at least 25 30 m uplift of the taihu block since the end of ois 3 we suggest that this uplift was mainly caused by the differential subsidence due to substantial amount of post glacial deposition by the changjiang and huanghe rivers on the continental shelf of east china marginal sea

absolute calibration of the greenland time scale implications for antarctic time scales and for δ14c abstract we propose a new age scale for the two ice cores grip and gisp2 that were drilled at greenland summit based on accelerator mass spectrometry 14c dating of foraminifera in core md95 2042 paleoceanography 15 2000 565 calibrated by means of recently obtained paired 14c and 230th measurements on pristine corals marine radiocarbon calibration curve spanning 10 500 to 50 000 years bp thousand years before present based on paired 230th 234u 238u and 14c dates on pristine corals geological society of america bulletin 2003 submitted for publication the record of core md95 2042 can be correlated very precisely to the greenland ice cores between 30 and 40 ka bp our scale is 1 4 ka older than the grip ss09sea time scale journal of quaternary science 16 2001 299 at the older end of marine isotope stage 3 we use published 230th dates from speleothems to calibrate the record using this scale we show a 14c record that is broadly consistent with the modelled record earth planet sci lett 200 2002 177 and with the data of hughen et al science 303 2004 202 but not consistent with the high values obtained by beck et al science 292 2001 2453 or by voelker et al radiocarbon 40 1998 517 we show how a set of age scales for the antarctic ice cores can be derived that are both fully consistent with the greenland scale and glaciologically reasonable

uniquely extensive soft sediment deformation in the rhaetian of the uk evidence for earthquake or impact the lower part of the cotham member in the penarth group latest triassic rhaetian of the uk incorporates a uniquely extensive metre scale horizon of soft sediment deformation interpreted as a seismite it shows evidence for only a single seismic event even at its thickest development it is recorded from more than forty sites across at least eight discrete sedimentary basins covering n250 000 km 2 and originally must have covered a still larger area such a widespread horizon of soft sediment deformation unique for the uk phanerozoic and implying a seismic event of exceptional magnitude is difficult to account for by conventional terrestrial mechanisms contemporaneous volcanism in the central atlantic magmatic province camp was too far distant to cause the deformation and the tectonic setting of the region was not conducive to earthquakes on this scale slump fold long axes suggest an epicentre broadly in the southern irish sea or st george s channel impact of a km scale asteroid here potentially could produce the observed sedimentological effects across the uk but any late triassic impact structure would now be concealed by a km or more of younger strata at its thickest development in northern ireland the seismite is succeeded by a rip up breccia and hummocky and wave rippled cross stratification these facies and their position immediately above the seismite are consistent with the effects of a tsunami arising directly from the seismic event tentative evidence for a tsunamite of this age has also been reported from southern france the putative tsunamite in northern ireland is succeeded by a desiccation cracked hiatus which may correlate with a similar hiatus truncating the seismite at sites in southern england the hiatus in southern england correlates closely with a 13 c isotope excursion that has been traced from eastern europe across to western north america and is associated with significant biotic changes the ultimate cause of the seismite and associated tsunamite remains unclear no impact crater of appropriate age or location is currently known and other evidence for impact at this time is at best equivocal it is considered here that impact of a km scale asteroid may have caused the observed sedimentological effects in the lilstock formation across the uk area but was not necessarily a significant contributory factor in the generation of either the isotope excursion or of the biotic changes through the triassic jurassic boundary interval

patterns of brachiopod faunal and body size changes across the permian triassic boundary evidence from the daoduishan section in meishan area south china abstract new analysis of permian triassic brachiopod assemblages and body size changes in south china provides insights into the process of the environmental crisis in the lead up to the end permian mass extinction the recently discovered daoduishan section of south china can be considered as an important auxiliary section for the study of brachiopods at the meishan section d of south china the gssp of the permian triassic boundary ptb this paper studied changes of the brachiopod assemblages and body sizes through the upper part of the changxing formation and basal yinkeng formation of daoduishan the results show that significant changes of brachiopod assemblages took place between beds 24e and 26 brachiopods prelissorhynchia sp and paracruirithyris pygmaea are the dominators in beds 14 24e while tethyochonetes pigmaea and paryphella spp are the dominators in beds 26 29 body sizes of brachiopods significantly decreased between beds 24e and 26 and then maintained smaller means in beds 27 29 studies of brachiopod morphological features indicate both tethyochonetes and paryphella had advantageous adaptations enabling them to copy with living in an anoxic dysoxic and or low productivity environment during the permian triassic crisis

seismites from a well core of palustrine deposits as a tool for reconstructing the palaeoseismic history of a fault abstract the concud fault is located at the junction between the jiloca and teruel grabens central eastern iberian chain spain the late pleistocene activity of this fault has been well logged from structural and palaeoseismological trench studies but only scattered data of the late pliocene seismic activity exist the late pliocene early pleistocene syn tectonic infill consists of an endorheic continental succession in which a 75 m long continuous well was drilled near the concud fault along the entire well core several types of soft sediment deformation structures with variable morphology size and frequency have occurred including clastic dykes load structures and slumps the rigorous analysis of the deformation structures their relationships with the involved sedimentary facies and the discrimination of possible deformation mechanisms and trigger processes allow us to interpret part of them as seismically induced structures the recognition of 21 deformed beds seismites allow the late pliocene early pleistocene seismic history of the concud fault to be reconstructed therefore 21 seismic events with m 5 and an apparent recurrence period of about 45 ka have been inferred

barriers and bridges early human dispersals in equatorial se asia past environments of equatorial se asia must have played a critical role in determining the timing and trajectory of early human dispersal into and through the region however very few reliable terrestrial records are available with which to contextualize human dispersal events this circumstance coupled with a sparse archaeological record and the likelihood that much of the archaeological record is now submerged means we have an incomplete understanding of the role that geography climate and environment played in shaping human pre history in this region from a review of the literature we conclude that there must have been a substantial environmental barrier resulting in a genetic separation between east and west sundaland that persisted even though a terrestrial connection was present for most of the pleistocene this barrier is likely to be a north south corridor of open non forest vegetation and its existence may have encouraged the rapid dispersal of early humans through the interior of sundaland and on to sahul we conclude that more reliable terrestrial palaeoenvironmental records are required to better understand the links between past environments and dispersal events we highlight avenues of particular research value such as focusing on eastern sumatra western southern borneo and the islands in the java sea where the purported savanna corridor most probably existed and including edaphic factors in palaeovegetation modelling

cultivation and human impact at 6000 cal yr b p in tropical lowland forest at niah sarawak malaysian borneo this paper describes palynological evidence for what appears to be comparatively large scale human impact in the catchment of the sungai niah in the wet tropical lowland swamp forests of sarawak malaysian borneo close to the great cave of niah pollen associated with cleared landscapes and rice cultivation is evident in the sedimentary record from before 6000 cal yr b p human activity seems to have been associated with changes in sedimentary regime with peat dominated environments being replaced diachronously by clay dominated deposition this may reflect anthropogenic soil erosion in the catchment of the sungai niah

extensive soft sediment deformation structures in the early darriwilian middle ordovician shallow marine siliciclastic sediments formed on the baltoscandian carbonate ramp northwestern estonia abstract the nearshore middle ordovician early darriwilian deposits of the baltoscandian basin formed on the flank of tectonically stable fennoscandian shield comprise numerous soft sediment deformation structures the areal extent of the deformed interval extends up to 9000 km 2 from nw estonia to se sweden the deformation structures occur within a meter scale sandstone horizon that includes load casts flame structures ball and pillow morphologies up to 2 m wide sedimentary dykes autoclastic breccias sand volcanoes and other related soft sediment deformation structures evidently these deformation structures formed during a single seismic event that caused liquefaction and fluidization of the water saturated unconsolidated shallow marine sediments within almost the entire sandstone unit pakri formation probably a unique catastrophic earthquake of magnitude 7 or higher occurred in this region penecontemporaneously with the deposition of these sediments the ultimate cause of seismic event of such magnitude in the tectonically stable baltoscandian basin is unclear however deposition and deformation of the pakri formation fall within the middle ordovician meteoritic bombardment period which resulted from the disruption of a large parent body in the asteroid belt approximately 470 ma ago this in turn suggests a potential impact origin for the single catastrophic earthquake in the tectonically stable study region although impact crater of suitable age is currently not known from the region then previous studies have documented some impact metamorphic shock lamellae i e pdfs and abundant extraterrestrial chromite grains from the deformed sediments

pedogenesis and geochemical alteration of the picture gorge subgroup columbia river basalt oregon reddened clay rich horizons between basalt flows have historically been identified as baked zones or as zones of lateral groundwater movement the reddening has been attributed to thermal or chemical alteration of the permeable portion of the basalt flow many of these red horizons are instead paleosols that record significant hiatuses in basalt flow emplacement paleosols were identified in the field on the basis of features such as horizonation ped morphology and root traces terrestrial gastropods fossil plants and peats also occur locally plots of weathering indices such as base loss are consistent with a pedogenic origin for these horizons ca na mg fe 21 and p have been extensively lost from the a and bt horizons of the paleosols consistent with modern weathering patterns k and rb have been added to the upper portions of the profiles and lost in the lower portions of the profiles relative to the parent material with rb added disproportionately historically this pattern of enrichment has been cited as evidence of k metasomatism the apparent metasomatism can be explained using a new model in which there was extensive felsic volcanism contemporaneous with pedogenesis and k and rb were likely added by windborne ash the apparent discordance between k and rb contents of the paleosols can be explained by the presence of land plants because k is an important electrolyte and rb does not serve any major biological role this model could account for apparent k metasomatism in other paleosols following the advent of land plants and may be applicable to older paleosols as well

mid to late holocene geomorphological and hydrological changes in the south taihu area of the yangtze delta plain china abstract the taihu plain of the lower yangtze valley china was a centre of rice agriculture during the neolithic period reasons for the rapid development of rice cultivation during this period however have not been fully understood for this coastal lowland which is highly sensitive to sea level change to improve understanding of the geomorphological and hydrological context for evolution of prehistoric rice agriculture two sediment cores dtx4 and dtx10 in the east tiaoxi river plain south taihu plain were collected and analysed for radiocarbon dating diatoms organic carbon and nitrogen stable isotopes 13c and 15n grain size and lithology these multiproxy analyses revealed that prior to ca 7500 cal yr bp the east tiaoxi river plain was a rapidly aggrading high salinity estuary the palaeo taihu estuary after ca 7500 cal yr bp low salinity conditions prevailed as a result of strong yangtze freshwater discharge subsequently seawater penetration occurred and saltmarsh developed between ca 7000 and 6500 cal yr bp due to accelerated relative sea level rise this transgression event influenced a large area of the taihu plain during the holocene as shown by multiple sediment records from previous studies persistent freshwater marsh or subaerial land formed due to dramatic shrinkage closure of the palaeo taihu estuary after ca 5600 cal yr bp when sea level was relatively stable we speculate that geomorphological and hydrological changes of the east tiaoxi river plain played an important role in agricultural development across the taihu plain during the neolithic period the closure of the palaeo taihu estuary and the formation of stable freshwater marsh or subaerial land after ca 5600 cal yr bp were critical preconditions encouraging the rapid rise of rice productivity in the liangzhu period 5500 4500 cal yr bp this development changed the landscape and river systems and thus provided adequate freshwater supply to the taihu plain

the applicability of the chemical index of alteration as a paleoclimatic indicator an example from the permian of the parana basin brazil abstract the chemical index of alteration cia was expressed as cia molar to become a more sensitive measure of the degree of chemical weathering the cia molar has the value of 1 for fresh feldspars and for unweathered non peraluminous igneous rocks but increases towards infinity as chemical weathering progresses the utility of this index as a humidity indicator for both modern and ancient muds was tested a database comprising 281 entries with chemical data for modern and ancient sediments deposited under arid semi arid semi humid and humid climate was assembled from the literature and used to calibrate the relationship between humidity and cia molar values for both modern and ancient sediments the histograms display a shift towards higher values with increasing geological indicators of humidity whereas sediments deposited under conditions inferred to be arid from other geological indicators show values tightly clustered around 1 the permian of the parana basin was then used as an example of the applicability of the cia molar for paleoclimatic studies major element analyses al2o3 k2o na2o cao were performed on 55 claystones and shales from three drill cores in a stratigraphic succession spanning the early to late permian the cia molar for these rocks accorded with expectations based on sedimentologic and paleontologic evidence discriminating well between arid and humid conditions in the basin independently determined from sedimentological and paleontological indicators the use of the cia molar as a paleo humidity indicator however can be limited by the presence of carbonate rich sediments the occurrence of post depositional k addition metasomatism metamorphism diagenetic illitization as well as by inheritance of clays from sedimentary rocks in the source area nevertheless with appropriate caution the cia molar is a useful tool for the assessment of the humidity conditions in the rock record

sedimentary record of seismic events in the eocene green river formation and its implications for regional tectonics on lake evolution bridger basin wyoming abstract outcrops and cores from the top of the lacustrine tipton member and the base of the wilkins peak member 51 5 ma of the eocene green river formation bridger basin in southwestern wyoming yield a wide variety of sedimentary deformation features many of which are laterally extensive for more than 50 km they include various types of folds load structures pinch and swell structures microfaults breccias and sedimentary dikes in most cases deformation is represented by hybrid brittle ductile structures exhibiting lateral variation in deformation style these occur in low energy profundal organic rich carbonate mudstones oil shales trona beds tuffs and profundal to sublittoral silty carbonate deposited in paleolake gosiute the deformation is not specific to the depositional environment because sedimentary units stratigraphically higher with similar facies show no deformation the studied interval lacks any evidence for possible trigger mechanisms intrinsic to the depositional environment such as strong wave action rapid sediment loading evaporite dissolution and collapse or desiccation so endogenic causes are ruled out thus the deformation features are interpreted as seismites and change in deformation style and inferred increase in intensity towards the south suggest that the earthquakes were sourced from the nearby uinta fault system the 22 levels exhibiting seismites recognized in cores indicate earthquakes with minimum magnitudes between 6 and 7 minimum epicentral intensity mcs of 9 and varying recurrence intervals in the seismic history of the uinta fault system with a mean apparent recurrence period of 8 1 k y using average sedimentation rates and dated tuffs in detail however there are two noticeably active periods followed by relative quiescence the stratigraphic position of these deformed intervals also marks the transition between two distinct stages in lake evolution from the balanced filled tipton member to the overlying underfilled wilkins peak member thus these seismites are evidence for regional scale changes in lacustrine sedimentation of eocene lake gosiute in response to syndepositional tectonic activity analysis of synsedimentary deformation features is therefore a promising yet under utilized tool to trace the tectonic evolution of lacustrine deposits of the green river formation and other tectonically active marine and non marine basins

a 50 000 year record of late pleistocene tropical vegetation and human impact in lowland borneo abstract there has been considerable uncertainty about the nature of pleistocene environments colonised by the first modern humans in island se asia and about the vegetation of the last glacial maximum lgm in the region here the palynology from a series of exposures in the great cave of niah sarawak malaysian borneo spanning a period from ca 52 000 to 5000 bp is described vegetation during this period was climate driven and often highly unstable interstadials are marked by lowland forest sometimes rather dry and at times by mangroves stadials are indicated by taxa characteristic of open environments or as at the lgm by highly disturbed rather open forest stadials are also characterised by taxa now restricted to 1000 1600 m above sea level suggesting temperature declines of ca 7 9 c relative to present by comparison with modern lapse rates the practice of biomass burning appears associated with the earliest human activity in the cave

nearshore offshore basin species diversity and body size variation patterns in late permian changhsingian brachiopods abstract body size is a fundamental and defining character of an organism and its variation in space and time is generally considered to be a function of its biology and interactions with its living environment a great deal of body size related ecological and evolutionary research has been undertaken mostly in relation to extant animals among the many body size related hypotheses proposed and tested the size bathymetry relationship is probably the least studied in this study we compiled a global body size dataset of changhsingian late permian ca 254 ma 252 ma brachiopod species from low latitude areas 30 s 30 n and analyzed their species diversity and body size distribution patterns in relation to the nearshore offshore basin bathymetric gradient the dataset contained 1768 brachiopod specimens in 435 species referred to 159 genera and 9 orders from 135 occurrences localities of 18 different palaeogeographic regions treating the whole of the changhsingian stage as a single time slice we divided the nearshore offshore basin bathymetric gradient into three broad depth related environments nearshore offshore and basinal environments and compared how the species diversity and body size varied along this large scale bathymetric gradient here we report an array of complex patterns first we found a clear overall inverse correlation between species diversity and water depth along the nearshore offshore basin gradient with most species concentrating in the nearshore environment second when the median sizes of all low latitude brachiopod species from the three environments were compared we found that there was no significant size difference between the nearshore and offshore environments suggesting that neither the wave base nor the hydrostatic pressure exerts a critical influence on the body size of brachiopods on the other hand the median sizes of brachiopods from the nearshore environment and to a lesser extent the offshore environment were found to be significantly larger than that of basinal brachiopods this trend of significant size reduction in basinal brachiopods mirrors the relative low species diversity in the basinal environment and neither can be easily explained by the tendency of decreasing food availability towards deeper sea environments rather both trends are consistent with the hypothesis of an expanding oxygen minimum zone omz in the bathyal slope to deepsea environments where hypoxic to anoxic conditions are considered to have severely restricted the diversification of benthos and favored the relative proliferation of small sized brachiopods finally a significant difference was also found between eurybathic and stenobathic species in their body size response to the nearshore offshore basin gradient in that eurybathic species species found in all three environments did not tend to change their body size significantly according to depth whereas stenobathic forms species restricted to a single environment exhibit a decline in body size towards the basinal environment this pattern is interpreted to suggest that bathymetrically more tolerant species are less sensitive to depth control with respect to their body size change dynamics in contrast to stenobathic species which tend to grow larger in shallower water depths

barium sio2 excess and p2o5 as proxies of biological productivity in the middle east during the palaeocene and the latest palaeocene benthic extinction event the distribution of barium and other elements related to biological productivity has been studied in two palaeocene sections from the middle east in the bathyal ben gurion section israel ba ba al2o3 15 concentrations are low in the range 0 04 to 0 3 in the lower palaeocene and very high 1 to 2 throughout most of the upper palaeocene in the neritic gebel aweina section in egypt ba values are low 0 1 throughout the entire palaeocene the ba enrichments at ben gurion and their correlations with increases in p2o5 and opaline silica and local and global 13c maxima indicate that upwelling and high productivity were important in this region during the late palaeocene the absence of ba enrichments in the shallower gebel aweina section probably reflects the strong depth dependence of biobarium deposition in the uppermost palaeocene at the level where the global benthic extinction event is registered ba concentrations in the ben gurion section increase to anomalous 6 which suggests that upwelling and possibly wind strengths intensified during this event the results speak against deep water formation in this region since downwelling and not upwelling is required

seismically triggered soft sediment deformation structures close to a major strike slip fault system in the eastern alps hirlatz cave austria abstract we investigate episodic soft sediment deformation structures cross cut by normal faults preserved in unlithified finely laminated calcite rich sediments in the hirlatz cave in the northern calcareous alps austria these sediments comprise varve like alternations of brighter carbonate quartz rich layers and darker clay mineral rich layers the deformed sediments contain abundant millimeter to centimeter scale soft sediment structures load casts ball and pillow structures sheet slumps thrust faults and folds erosive channels filled with slides and chaotic slumps after deposition and soft sediment deformation normal faults developed within the entire sedimentary succession an event that probably correlates with an offset of c 10 cm of the passage wall above the outcrop our major conclusions are i the sediments have a glacial origin and were deposited in the hirlatz cave under phreatic fluvio lacustrine conditions the deposition and the soft sediment deformation occurred most likely during the last glaciation i e around 25 ka ago ii the liquefaction and formation of the soft sediment structures in water saturated stratified layers was triggered by episodic seismic events iii the internally deformed sediments were later displaced by normal faults iv a possible source for the seismic events is the active sinistral salzach ennstal mariazeller puchberger semp strike slip fault which is located about 10 km south of the outcrop and plays a major role in accommodating the extrusion of the eastern alps towards the pannonian basin to our knowledge the described structures are the first report of liquefaction and seismically induced soft sediment deformations in quaternary sediments in the eastern alps

features and sealing mechanism of shallow biogenic gas in incised valley fills the qiantang river eastern china a case study abstract late quaternary shallow biogenic gas reservoirs have been discovered and exploited in the qiantang river qr estuary area eastern china the fall of global sea level during the last glacial maximum resulted in the formation of the qr incised valley from bottom to top the incised valley successions can be grouped into four sedimentary facies river channel facies floodplain estuarine facies estuarine shallow marine facies and estuarine sand bar facies all commercial biogenic gas pools occur in floodplain estuarine sand bodies of the qr incised valley and its branches the deeply incised valleys provided favorable conditions for the generation and accumulation of shallow biogenic gas the clay beds that serve as the direct cap beds of the gas pools are mostly restricted within the qr incised valley with burial depths ranging from 30 to 80 m remnant thicknesses of 10 30 m and porosities of 42 2 62 6 in contrast the mud beds cover the whole incised valley and occur as indirect cap beds with burial depths varying from 5 to 35 m thicknesses of 10 20 m and porosities of 50 6 53 9 the pore water pressures of clay and mud beds are higher than that of sand bodies and the difference can be as much as 0 48 mpa the pore water pressures of clay or mud beds can exceed the total pore water pressure and gas pressure of underlying sand reservoirs shallow biogenic gas can be completely sealed by the clay and mud beds which have higher pore water pressure the direct cap beds have better sealing ability than the indirect cap beds generally the pore water pressure dissipation time of clay and mud beds is conspicuously longer than that of sand beds this indicates that the clay and mud beds have worse permeability and better sealing ability than the sand beds however once the gas enters the sand lenses the pore water pressure cannot release efficiently

oxygen isotope and palaeotemperature records from six greenland ice core stations camp century dye 3 grip gisp2 renland and northgrip oxygen isotope variations spanning the last glacial cycle and the holocene derived from ice core records for six sites in greenland camp century dye 3 grip gisp2 renland and northgrip show strong similarities this suggests that the dominant influence on oxygen isotope variations reflected in the ice sheet records was regional climatic change differences in detail between the records probably reflect the effects of basal deformation in the ice as well as geographical gradients in atmospheric isotope ratios palaeotemperature estimates have been obtained from the records using three approaches i inferences based on the measured relationship between mean annual 18o of snow and of mean annual surface temperature over greenland ii modelled inversion of the borehole temperature profile constrained either by the dated isotopic profile or iii by using monte carlo simulation techniques the third of these approaches was adopted to reconstruct holocene temperature variations for the dye 3 and grip temperature profiles which yields remarkably compatible results a new record of holocene isotope variations obtained from the northgrip ice core matches the grip short term isotope record and also shows similar long term trends to the dye 3 and grip inverted temperature data the northgrip isotope record reflects i a generally stronger isotopic signal than is found in the grip record ii several short lived temperature fluctuations during the first 1500 yr of the holocene iii a marked cold event at ca 8 2 ka the 8 2 ka event iv optimum temperatures for the holocene between ca 8 6 and 4 3 ka a signal that is 0 6 stronger than for the grip profile v a clear signal for the little ice age and vi a clear signal of climate warming during the last century these data suggest that the northgrip stable isotope record responded in a sensitive manner to temperature fluctuations during the holocene copyright 2001 john wiley sons ltd

modifying the marsh evaluating early epipaleolithic hunter gatherer impacts in the azraq wetland jordan the ecological impacts of human activities have infiltrated the whole of the natural world and precipitated calls for a newly defined geological epoch the anthropocene while scholars discuss tipping points and scale viewed over the longue duree it is becoming clear that we have inherited the compounding consequences of a constructed environment with a long history of human landscape modification by linking phytolith and micro charcoal evidence from sediments in the azraq basin jordan we discuss potential early epipaleolithic 23 000 17 400 cal bp human environment interactions in this wetland our analyses reveal that during the last glacial maximum levantine hunter gatherers could have had a noticeable and increasing impact on their environment however further work needs to be undertaken to assess the range frequency intensity and intentionality of marsh disturbance events we suggest that the origin of persistent places and larger aggregation settlements in the azraq basin may have b

seismic influence on the last 1500 year infill history of lake sapanca north anatolian fault nw turkey article i nfo lake sapanca is located on the north anatolian fault zone in nw turkey it occupies a pull apart basin at the junction between the izmit sapanca fault segment the sakarya segment and the westernmost end of the mudurnu valley fault multiproxy analyses lithology loss on ignition geochemistry magnetic susceptibility and palynology of a 586 cm long sediment core taken in the centre of the lake revealed a complex history of at least five mass movement events the radiocarbon chronology suggests that the sediment sequence spans approximately the last 1500 years the bottom metre of the sequence before c ad 580 is a gley soil resulting from a large sublacustrine landslide whose origin is a collapse of the floodplain between the lake and river sakarya sedimentation related to this eastern floodplain decreases progressively until c ad 910 sedimentological and palynological indicators from sediments younger than c ad 910 document four major episodes of mass movement originating most likely from the southern slopes of the lake the landslide and the following four mass movement events are suggested to be linked to earthquakes

shell gathering from mangroves and the seasonality of the southeast asian monsoon using high resolution stable isotopic analysis of the tropical estuarine bivalve geloina erosa from the great cave of niah sarawak methods and reconnaissance of molluscs of early holocene and modern times this paper describes a reconnaissance high resolution study of stable isotopes 18o and 13c from modern shells of the estuarine bivalve geloina erosa and those dated to the early holocene that were harvested by people from mangroves near the great cave of niah on the north coast of borneo this reconnaissance study provides high resolution palaeoclimatic palaeohydrological information concerning early human activity in the region and the past character of the southeast asian monsoon laser ablation continuous flow isotope ratio mass spectrometry la cf irms on modern shells of geloina erosa revealed saw tooth stable isotopic profiles that bear a close resemblance to peaks and troughs of trends in recent local rainfall including the 1998 el nino drought highlighting the potential of geloina erosa for reconstructing seasonality of the southeast asian palaeomonsoon la cf irms analysis of prehistoric shells of geloina erosa held in the harrisson archives of the sarawak museum revealed cyclical shifts in 18o with similar amplitudes of variation as found in modern shells of geloina erosa as at the present day this probably reflects the changing seasonality of the monsoon rains with shifts to negative 18o values during periods of high runoff lighter mean 18o values of the prehistoric shells however may indicate a greater annual surplus of rainfall and possibly consistent with the early holocene strengthening of the summer monsoon at that time the similarity of the last growth increment 18o of the prehistoric shells to their mean 18o profile values suggests that gathering took place during times of moderate runoff

early mid holocene sea level change and coastal environmental response on the southern yangtze delta plain china implications for the rise of neolithic culture abstract we used a series of holocene sediment cores with ams 14c dated basal saltmarsh peat and supratidal sediment to reconstruct early mid holocene sea level change on the southern yangtze delta plain we also synthesized results for ca 150 late quaternary cores as well as archeological data to reveal the unique interplay between coastal evolution and neolithic cultural response relative sea level was ca 16 5 to 14 5 m from 8600 to 8500 cal bp and ca 6 to 4 m from 7400 to 7200 cal bp reflecting the rate of eustatic sea level rise but being ca 10 m higher possibly because of the effect of hydro istostasy three late pleistocene interfluve terraces t3 to t1 were revealed at burial depths of

clastic dykes of the devono carboniferous horton bluff formation nova scotia storm related structures in shallow lakes abstract clastic dykes are common in the late devonian to early carboniferous horton bluff formation of nova scotia where they occur in wave dominated shoreline deposits of lacustrine shoaling upward cycles the dykes typically less than 25 cm wide and 40 cm in vertical extent project downward into clayshale from broad loads at the base of elongate isolated lenses of hummocky cross stratified siltstone ptygmatic folding of the dykes reflects a shale siltstone compaction ratio of 2 3 times and maximum depth of dyke penetration prior to compaction was 1 m dyke orientation parallels the orientation of wave ripple crests and the elongation direction of the siltstone lenses dyke formation was penecontemporaneous with sedimentation dyke and load formation was probably initiated in shallow water during storms which promoted sediment failure through cyclic wave loading microseisms and rapid deposition of hcs bearing siltstone lenses reversed density gradient and uneven sediment loading from silt lenses probably promoted downward emplacement loads reflect ductile failure of surficial water rich mud whereas dykes reflect downward injection of silt following brittle failure of underlying more compacted mud the depositional slope provided a tensional stress that controlled the fracture direction orthogonal to the slope of the failed sediment

seismites as a tool in the palaeoenvironmental reconstruction of fluvial deposits the cambrian guarda velha formation southern brazil abstract soft sediment deformation ssd is widely described in the literature but there is no clear consensus regarding its origin and significance existing models for ssd in fluvial sediments do not clearly demonstrate a relationship between the structures preserved facies expression and larger scale depositional architecture in this study several types of ssd structures are recorded in cambrian fluvial deposits and these occur interbedded with undeformed strata throughout the entire stratigraphic interval the random distribution of these features in relation to primary facies types and fluvial forms indicates that they have neither a direct nor indirect relationship with any depositional processes or bedform type we propose that the relationship of ssd at the bed set scale to larger scale depositional architecture combined with tectono stratigraphic analysis allows the determination of both short term fluvial hydraulic conditions in ancient stream systems such as the nature of the flow regime responsible for depositing ancient fluvial stream successions and the long term subsidence rates in the form of mean recurrence interval of the seismic events responsible for triggering the generation of ssd in tectonically active basins

carbonate sedimentation in a permian high latitude subpolar depositional realm queensland australia high latitude carbonate rocks that formed in subpolar paleozoic oceans contain critical information about past climate but they are neither well documented nor fully understood lower and middle permian limestones that were deposited in such paleoenvironments at 45 s to 55 s along the southeastern margin of gondwana are now exposed in eastern australia such carbonates constitute a small but important and well preserved part of the siliciclastic glacigene succession in the bowen basin from southern and central queensland cleanest limestones accumulated on topographic highs in the eastern seaward parts of the basin that were isolated from siliciclastic sediment input from the western craton shallow water deposits are composed of large eurydesmid bivalves spiriferid and productid brachiopods bryozoans infaunal and epifaunal benthic foraminifers calcareous sponge spicules and abundant crinoids in the form of locally cross bedded rudstones and grainstones deeper water muddy carbonates are dominated by bryozoans crinoids and productids shells and spines deepest water sediments are argillaceous floatstones or shales containing fenestrate bryozoans thin walled productids and siliceous sponge spicules when integrated with recent studies of coeval sedimentary rocks along the 2000 km long paleocontinental margin a clear pattern of sedimentation emerges wherein deposition took place in similar settings during three discrete periods of deglaciation late sakmarian late artinskian and wordian all of the carbonates are distinguished by a low diversity high abundance heterozoan biota with no phototrophs and express a recurring deepening upward stratigraphic motif that is interpreted to reflect rising sea level accompanying glacial meltdown they also record a strong poleward gradient of increasing ice rafted debris increasing skeleton size decreasing invertebrate diversity decreasing epifaunal calcareous benthic foraminifers and reduction in crinoids glendonites are confined to siliciclastic sediments deposited during glacial periods comparison with coeval northern hemisphere carbonates indicates a strong parallelism of facies and depositional systems this study helps to establish these deposits as a template for a global paleozoic high latitude carbonate facies model

marine sediment records and relative sea level change during late pleistocene in the changjiang delta area and adjacent continental shelf abstract optically stimulated luminescence osl dating and microfossil analysis were conducted on late quaternary samples from two boreholes in the changjiang delta area successions from 12 collected boreholes revealed lithology stratigraphy and sedimentary facies of the changjiang delta area and continental shelf of the east china sea ecs these data were used to determine the chronology of two transgressions during marine isotope stage mis 5 and mis3 interpret the sedimentary facies and mechanisms of the distinctive transgression pattern and reconstruct relative sea level of the study area during late mis3 fluvial gravelly sediment deposition prevailed with limited marine influence during mis5 while muddy and sandy deposition occurs along with widespread coastal facies during mid and late mis3 in the changjiang delta area this suggests that the study area was dominated by high relief and local rivers developed with large freshwater and sediment discharge during mis5 therefore marine micro faunas may not have survived due to dominant freshwater process or strong erosion has scoured away the marine records of mis5 tectonic subsidence is indicated to occur at a rate of 1 m ka since mis5 and lower the changjiang coastal area to be invaded by seawater during mis3 the altitude of late mis3 transgressive sediments decreases from the inner delta plain seaward gradually reflecting differential tectonic subsidence of the study area abrupt sea level rise occurred and relative sea level is proposed as 5 m during late mis3

earthquake induced soft sediment deformation structures in upper jurassic open marine microbialites neuquen basin argentina penecontemporaneous decimetre scale soft sediment deformation structures are reported from the basal part of the upper jurassic lower cretaceous vaca muerta formation in the malargue las lenas area of the back arc neuquen basin mendoza province central andes the deformed interval amarillas bed is only 0 3 to 0 9 m thick but occurs in a wide area larger than 1500 km2 its age determined by ammonite biostratigraphy is early tithonian the soft sediment deformation structures were generated in finely laminated partially consolidated organicrich carbonate microbialites that were deposited in open marine poorly oxygenated settings apparently devoid of any significant slope those structures include boudins of different sizes and complexity a variety of folds normal listric dm scale faults sub horizontal detachment surfaces and other features which are part of several larger scale complex slump structures deformation was dominantly plastic but near to the ductile brittle field transition on the basis of the observed soft deformation structures their geographic distribution their lateral homogeneity and the geodynamic framework of the basin in which it was generated the amarillas bed can be tentatively attributed to a large intermediate depth earthquake that occurred within the plate that subducted beneath the andean continental margin and the neuquen back arc basin

post depositional alteration of humid tropical cave sediments micromorphological research in the great cave of niah sarawak borneo the post depositional alteration of cave sediments is of critical importance for the recognition identification and investigation of geoarchaeological and palaeoenvironmental evidence there have been relatively few studies of tropical cave sediments using micromorphology and this work represents one of the most detailed with 26 samples taken from deposits in the west mouth of the great cave of niah that cover the last 55 000 bp and contain the earliest known evidence for the remains of modern humans in southeast asia cave sediments situated in the humid tropics are subject to relatively high temperatures and moisture conditions that promote high rates of chemical alteration and geomorphic change this paper outlines those post depositional features that occurred in situ in the west mouth and include translocation and concentration bioturbation excrement bone alteration plant alteration clast alteration and guano decomposition it examines their implications for recognising past human activities e g fire altered materials the preservation of archaeological remains the nature of palaeoenvironments and of localised physical and bio geochemical processes

a late pleistocene record of climate and environmental change from the northern and southern kelabit highlands of sarawak malaysian borneo a late pleistocene vegetation record is presented using multi proxy analysis from three palaeochannels in the northern bario and southern pa dalih kelabit highlands of sarawak malaysian borneo before 50 000 cal a bp and until 47 700 cal a bp marine isotope stage 3 mis3 two of the sites were probably being influenced by energetic fluvial deposition possibly associated with strong seasonality fluvial activity declines between 47 700 and 30 000 cal a bp mis3 and may be associated with a reduction in seasonality with overall stability in precipitation the pollen record between 47 700 and 30 000 cal a bp generally shows much higher representation of upper montane taxa compared with the holocene indicating often significantly reduced temperatures after 35 000 30 000 cal a bp and until the mid holocene hiatuses appear in two of the records which could be linked to fluvial down cutting during the late mid holocene despite the jump in ages a pronounced representation of ericaceae and upper montane taxa represented both at bario and at pa dalih corresponds to a further lowering of temperatures during the last glacial maximum mis2 thick charcoal bands in the pdh 210 record also suggest periods of extreme aridity between 30 200 and 12 700 cal a bp this is followed by energetic fluvial deposition of sands and gravels and may reflect a significant increase in seasonality

abrupt environmental and climatic change during the deposition of the early permian haushi limestone oman during the late sakmarian early permian the haushi limestone was deposited in a shallow embayment of the neotethys ocean covering what is now north oman and parts of southeast saudi arabia the sea persisted through the late sakmarian but by the time of the deposition of the artinskian middle gharif member limestone deposition had ceased and generally arid fluvial and minor lacustrine palaeonvironments in a low accommodation space setting had become established analysis of three subsurface cored boreholes and other surface sections of the haushi limestone shows an upward change in microfacies from bryonoderm to molechfor associations reflecting the passage from heterozoan to photozoan communities the biotic turnover indicates cooler climate and eutrophy in the lower parts of the unit and an upward trend towards warmer climate and more oligotrophic conditions in the upper part common autochthonous algal palynomorphs and high 13corg in the lower part suggest that high nutrient levels were due to greater fluvial runoff while allochthonous pollen assemblages indicate that the climate of the hinterland became more arid through the deposition of the unit causing upward increasing seawater trends in 18ocarb several extraneous factors are likely to have contributed to this palaeoenvironmental change which was more abrupt than in other parts of post glacial early permian gondwana first the haushi sea being an embayment partially isolated by hawasina rift shoulder uplift was more vulnerable to changes in rainfall and runoff than an open sea second continued post glacial global warming and small northward movement of gondwana may have contributed to temperature increase aridity may have been caused by the onset of monsoons and the influence of rift shoulders to the northeast and southeast

redating the onset of burning at lynch s crater north queensland implications for human settlement in australia lynch s crater preserves a continuous high resolution record of environmental changes in north queensland this record suggests a marked increase in burning that appears to be independent of any known major climatic boundaries this increase is accompanied or closely followed by the virtually complete replacement of rainforest by sclerophyll vegetation the absence of any major climatic shift associated with this increase in fire frequency therefore has been interpreted as a result of early human impact in the area the age for this increase in burning on the basis of conventional radiocarbon dating was previously thought to be approximately 38000 c 14 yr bp supporting the traditional model for human arrival in australia at 40 000 c 14 yr bp here we have applied a more rigorous pre treatment and graphitisation procedure for radiocarbon dating samples from the lynch s crater sequence these new dates suggest that the increase in fire frequency occurred at 45 000 c 14 yr bp supporting the alternative view that human occupation of australia occurred by at least 45 000 55 000 cal yr bp copyright c 2001 john wiley sons ltd

uv fluorescence microscopy and the coherence of pollen assemblages in environmental archaeology and quaternary geology abstract uv fluorescence microscopy provides a powerful tool for the assessment of the coherence of pollen and organic walled microfossil assemblages in situations where recycling or the intrusion of younger pollen is suspected it also provides sensitive information about the thermal maturity of pollen important for assessing whether material has been heated examples are given from the palaeolithic sites at barnham suffolk uk stanton harcourt oxfordshire uk high lodge suffolk uk niah cave sarawak malaysian borneo and holocene sites at wadi dana jordan milldale and creswell derbyshire uk and dooncarton mountain county mayo republic of ireland

seismically induced soft sediment deformation structures in the palaeogene deposits of the liaodong bay depression in the bohai bay basin and their spatial stratigraphic distribution abstract soft sediment deformation structures ssds have been identified from well cores in the palaeogene deposits of the liaodong bay depression in the bohai bay basin china these deposits formed as interbedded sand and mud at a delta front or on the slope toe of the prodelta according to criteria proposed by previous research we established that these ssds were induced by earthquakes and that they can be divided into two groups ductile deformation structures plastic intrusions ball and pillow structures flame structures boudinage structures irregular convolute stratifications and synsedimentary faults and folds and brittle deformation structures sand dykes and autoclastic breccias based on their level of deformation size and complexity the ssds were divided into three groups from weak to strong to reflect the intensity of palaeo earthquakes with consideration of the palaeo sedimentary environment we proposed a model to account for the production and preservation of these ssds according to the classification adopted in this study and the spatial stratigraphic distribution of the ssds the tectonic activities of the tan lu faults in the bohai bay basin were investigated the a and b oilfields assumed names are located in the tectonically active zones of the west and east branches of these faults respectively the extension tectonic activities in the a oilfield region exhibit a sharply decreasing trend from e2s3 to e2s1 and increase again in e3d2 whereas the strike slip tectonic activities in the b oilfield region exhibit an increasing trend from e2s3 to e2s1 and finally reach a maximum to e3d3 the results of this study show that the method of analysis of the spatial stratigraphic distribution of ssds is suitable for determining the evolution of tectonic activity and thus it can provide a new perspective for basin analysis

quantitative paleoenvironmental and paleoclimatic reconstruction using paleosols abstract paleosols fossil soils are preserved throughout the geologic record in depositional settings ranging from alluvial systems to between basalt flows until recently paleosols were studied using primarily qualitative methods in recent years paleopedology has shifted from a largely qualitative field based on comparisons with modern analogues to an increasingly quantitative endeavor some of this change has been a result of applying existing techniques to new materials but many of the innovations have been the result of applying new techniques to new materials including thermodynamic modeling of soil formation isotope geochemistry and applications of empirical relationships derived from modern soils a variety of semi quantitative and quantitative tools has been developed to examine past weathering and pedogenesis and to reconstruct both paleoenvironmental and paleoclimatic conditions at the time that the paleosols formed though it is often not possible to achieve the same temporal resolution as with marine records for paleoclimatic reconstructions proxies based on paleosols are potentially a much more direct means of making paleoclimatic reconstructions because soils form at the earth s surface in direct contact with the atmospheric and climatic conditions at the time of their formation paleoclimatic and environmental properties that may be reconstructed using the new proxies include provenance weathering intensity mean annual precipitation and temperature during pedogenesis nutrient fluxes into and out of the paleosols the atmospheric composition of important gases including co2 and o2 the moisture balance during pedogenesis the soil gas composition reconstructed vegetative covering and paleo altitude

natural and human impacts in a 35 000 year vegetation history in central new britain papua new guinea abstract phytoliths and micro charcoal from the yombon airstrip archaeological site in central new britain papua new guinea provide the longest vegetation history record yet available for the new guinea islands the record begins about 35 kya with the first evidence for human presence at the site and with the exception of the last glacial maximum period is continuous to the present three other sites provide supplementary evidence including plant macro remains from the early holocene onwards the record is punctuated by a series of volcanic events which are reflected in the vegetation record by alternating frequencies of closed forest and regrowth elements micro charcoal is present from the oldest levels and fluctuates in frequency throughout the sequence increasing substantially from the terminal pleistocene early holocene onwards this coincides with the first appearance of panicoid grasses and a range of potential cultivars including bananas and saccharum increased levels of burning coinciding with the appearance of potential plant cultivars may indicate shifts in plant food production leading to cultivation from the early holocene onwards this compares favourably with previously reported evidence from garua island off the north coast of new britain the combination of trends in burning vegetation clearance and appearance of potential cultivars on new britain appears to parallel changes in the papua new guinea highlands at a similar time and suggests regional similarities in subsistence and vegetation management practices from before the lgm onwards further studies are needed to clarify the timing and extent of these shifts across the region and to provide a vegetation picture for the period before human colonisation of new britain

early cretaceous slumps and turbidites with peculiar soft sediment deformation structures on lingshan island qingdao china indicating a tensional tectonic regime abstract some sections on lingshan island in the yellow sea close to the city of qingdao show the early cretaceous lingshandao formation the exposed succession consists mainly of turbidites some of which show uncommon soft sediment deformation structures and contains well developed large scale slumps that consist of sets of turbidites the sediments were deposited as part of lobes of turbidites and hyperpycnites deposits of flood generated sediment laden bottom currents derived from an estuary in a deep sea environment that formed part of an inter arc basin with a tensional tectonic regime some of the slumps have dimensions of the order of metres to tens of metres they consist of the turbidites that build most of the succession the soft sediment deformation structures in the turbidites represent a wide variety of types most of which are common in subaqueous environments with a high accumulation rate the most interesting are however structures that indicate active tectonic tension these structures are boudins which are present with two subtypes the most common are pinch and swell structures sometimes leading to isolated parts of the affected sandy layer enveloped by shales of the under and overlying shale layers the second type consists of domino boudins which have as far as we are aware of not earlier been described from sediments that were still unlithified during their formation the presence of the boudins and associated structures which indicate synsedimentary stretching related to an extensional tectonic setting form an additional argument in the long lasting debate about the question of whether a compressional or an extensional tectonic regime dominated in the area during the early cretaceous

experimental soft sediment deformation structures formed by the liquefaction of unconsolidated sands and some ancient examples the effects of liquefaction in saturated sand bodies under a variety of driving forces are described from shaking table experiments and structures from the geological record are presented which are analogous to the experimental structures the collapse of sloping heaps of cross bedded sand under a gravitational body force generates low angle essentially uncontorted stratification a basal zone of shearing may be present with steepened and folded foresets stretching of foresets may be accommodated on normal faults and bottomsets may be contorted into inclined folds in natural systems the substrate may also liquefy causing deformation driven by an unevenly distributed confining load stratification in the surface bedform is flattened and stratification in the substratum contorted experiments failed to produce relative displacement at the interface between stacked sand bodies liquefaction of gravitationally unstable systems in sands generates load structures comparable to those from sand mud systems recumbent folded deformed cross bedding is formed by current shear over a liquefied bed as has been inferred from field and theoretical analyses shear of nonliquefied sand forms angular folds other deformation mechanisms such as fluidization or seepage may generate structures similar to all of these local water escape structures driven by fluidization occur in the upper parts of some liquefied sand bodies they include cusps sand volcanoes and clastic dykes transient cavities formed in some experiments and seemed to be preserved as breached cusps although the experiments tried to isolate individual driving forces driving forces may operate together and there may be a continuum between deformation driven by water escape and deformation driven by loading different structures from those described here may form where liquefaction develops in a buried layer as opposed to at the sediment surface

modern humans in sarawak malaysian borneo during oxygen isotope stage 3 palaeoenvironmental evidence from the great cave of niah abstract during recent reinvestigations in the great cave of niah in borneo the hell trench sedimentary sequence seen by earlier excavators was re exposed early excavations here yielded the earliest anatomically modern human remains in island southeast asia calibrated radiocarbon dates pollen algal microfossils palynofacies granulometry and geochemistry of the hell trench sequence provide information about environmental and vegetational changes elements of geomorphic history and information about human activity the hell sediments were laid down episodically in an ephemeral stream or pool the pollen suggests cyclically changing vegetation with forest habitats alternating with more open environments indicating that phases with both temperatures and precipitation reduced compared with the present these events can be correlated with global climate change sequences to produce a provisional dating framework during some forest phases high counts of justicia a plant which today colonises recently burnt forest areas point to fire in the landscape this may be evidence for biomass burning by humans presumably to maintain forest edge habitats there is evidence from palynofacies for fire on the cave floor in the hell area since the area sampled is beyond the limit of plant growth this is evidence for human activity the first such evidence is during an episode with significant grassland indicators suggesting that people may have reached the site during a climatic phase characterised by relatively open habitats 50 ka thereafter people were able to maintain a relatively consistent presence at niah the human use of the hell area seems to have intensified through time probably because changes in the local hydrological regime made the area dryer and more suitable for human use

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

documentation of earthquake induced disturbance of lake sediments using subbottom acoustic profiling subbottom acoustic profiling in lakes on the canadian shield and in the canadian cordillera has revealed disruptions in deltaic and lacustrine sediments that can be attributed to large historical earthquakes the timiskaming earthquake of 1935 magnitude 6 25 and the vancouver island earthquake of 1946 magnitude 7 2 triggered extensive slumping and flow of postglacial sediments in lakes located within a few tens of kilometres of the epicentres of these events there is some evidence in one of the surveyed lakes for in situ mobilization of sediment on relatively gentle slopes with minimal horizontal displacement this may be a product of liquefaction induced by coseismic shaking or displacements along faults beneath the basin in another lake widespread coseismic slumping resuspended large amounts of fine sediment which then settled out onto the lake floor to produce a texturally anomalous layer features similar to those produced by the 1935 and 1946 earthquakes can also result from a variety of non

a biomass burning record from the west equatorial pacific over the last 360 ky methodological climatic and anthropic implications abstract to reconstruct past fire activity in the west pacific east asian region we investigate a 360 ky pelagic sedimentary record from the caroline basin in the western pacific warm pool wpwp core md97 2140 2547 m water depth in the lack of standard protocol and terminology for the determination of combustion derived products in sedimentary archives three proxies were compared with other paleoceanographic proxies oxidation resistant elemental carbon orec black carbon bc and microcharcoal the mineral caco3 and organic carbon corg records of core md97 2140 generally covary with the oxygen isotope record suggesting that glacial interglacial changes in ice volume and sea level control the preservation of caco3 and terrigeneous inputs of corg in the deep sea sediments of the caroline basin the changes in orec are primarily connected to the changes in corg record in contrast the bc and charcoal records which better reflect the input of biomass burning products are tightly connected with changes in the precession band 23 ky likely through low latitude atmospheric circulation patterns a peculiar control by the competing influence of the long term el nino southern oscillation enso like forcing and the glacial interglacial cycle on the east asian summer monsoon 30 19 11 and 6 ky periods is suggested in addition large increases in bc and charcoal are observed between ca 53 43 and 12 10 ky bp these events strikingly correspond to the main late pleistocene and early holocene periods of human colonization in the region likely suggesting an additional anthropic impact on the fire activity

stratigraphic paleoecology bathymetric signatures and sequence overprint of mollusk associations from upper quaternary sequences of the po plain italy upper quaternary sequences of the po plain italy were used to assess the informative strength and sequence stratigraphic overprint of quantitative paleoecological patterns three densely sampled cores 89 samples 98 genera 23 280 specimens dominated by extant mollusk species with known environmental distributions were analyzed with detrended correspondence analysis dca the dca scores calibrated using extant genera provided outstanding estimates of bathymetry 3 m and related environmental parameters depth related successions of mollusk associations delineated by using dca were consistent with independent sequence stratigraphic interpretations and yielded insights inaccessible via routine techniques e g depth estimates for maximum flooding surfaces the dca ordination demonstrates the severity of the sequence stratigraphic overprint samples are highly uniform taxonomically during late transgressive systems tracts and highly variable during the following highstand systems tracts when analyzed across comparable systems tracts similar species associations repeat during the last and current interglacial cycles suggesting that po plain mollusk associations have remained remarkably stable over the past 125 k y the results are consistent with the bathymetric interpretation of the dc axis 1 postulated previously for the paleozoic fossil record demonstrate the sequence stratigraphic overprint of paleoecological patterns predicted by computer modeling and illustrate the utility of quantitative paleoecological patterns in augmenting sequence stratigraphic interpretations

sedimentary records of paleoseismic events in the late pleistocene sediments of the southern yangtze river deltaic plain east china and their implications for differential subsidence of the taihu block abstract drilling cores from the hangjiahu coastal plain in the southwestern corner of the southern yangtze river deltaic plain east china contain a variety of soft sediment deformation structures in the late pleistocene lacustrine and tidal sediments they include load flame structures ball and pillow structures diapir structures liquefied sand veins liquefied breccias syn sedimentary fault seismo cracks and brittle breccias sedimentary facies assessment of host deposits and development features rule out an exogenic origin of the soft sediment deformation structures such as gravity flow storm activity wave action or flood these soft sediment deformation structures in the study area are interpreted as seismites their spatial distribution suggest that the earthquakes were sourced from the intersection of the majin wuzhen fault and the huzhou jiashan fault seismites recognized in cores indicate three episodes of short and sudden seismicity magnitude 5 which are interpreted as a response to syn depositional tectonic activity and differential subsidence of the taihu block during the late pleistocene period systematic study of spatial and temporal distribution of these seismites improves the understanding of the tectonic context and evolutionary history of sedimentary basement

the potential of lake ohrid for long term palaeoenvironmental reconstructions abstract lake ohrid at the macedonian albanian border was likely tectonically formed during the tertiary and therefore is one of the oldest lakes in europe however only a few studies exist concerning the potential of lake ohrid sediments for long term palaeoenvironmental reconstructions within the scope of future potential deep drilling campaigns therefore as a first step a transect of short surface sediment cores was investigated for chronology physical properties grain size and biogeochemistry the results were compared with information derived from a shallow hydro acoustic seismic survey the investigations indicate a rather uniform and bioturbated sedimentation in the central part of the lake basin with mean sedimentation rates of ca 0 5 1 mm year the sediment composition is dominated by authigenetic carbonates diatom frustules or fragments form the major part of biogenic matter deposits as indicated by the relatively high contents of biogenic opal and low contents of total organic carbon and total nitrogen the shallow hydro acoustic seismic survey indicates that horizons of sediment redeposition occur sporadically towards the shore of the lake the sedimentation rate increases and sedimentation is increasingly influenced by local inflows or mass movement processes triggered by tectonic activities thus lake ohrid has a high potential for palaeoenvironmental reconstructions on a multi decadal scale and provides additional information concerning tectonic activity in the region

local scale proxy evidence for the presence of closed canopy forest in north western borneo in the late pleistocene bones of strategy i bats from the archaeological record of the great cave of niah sarawak abstract the limits of the distribution of closed canopy forest in southeast asia during the glacial cycles of the pleistocene are the subject of continuing debate in this context this paper reports the results of an analysis of a novel line of evidence as a local scale case study 22 dated assemblages of bat bones that were recovered from the archaeological sequences of the great cave of niah in sarawak malaysian borneo were examined by examination of the morphological characteristics of the distal articulation of the humerus seven families and nine genera were identified five species level attributions could be made these assemblages formed a time series of 14 chronological intervals 48 0 35 ky bp ky bp 103 calibrated years before present 1950 incorporating samples from the high glacial interval 26 18 ky bp and last glacial maximum 23 19 ky bp bones of bat taxa that are adapted to forage in the cluttered environments in the interior of closed canopy forest strategy i bats were employed as proxy evidence for the presence of closed canopy forested habitats in the vicinity bones of strategy i bats principally small hipposideros spp were identified in all examined assemblages and intervals in the time series statistical testing indicated no evidence of differences in the absolute frequency of distal humeri from strategy i bats in the pleistocene samples 48 11 8 ky bp or in the entire time series 48 0 35 ky bp and no significant linear trend was found in the time series to suggest an increase of the bones strategy i bat taxa with the onset of the holocene these findings suggest that closed canopy forest habitats have been a persistent component in the landscape around the great cave of niah since 48 ky bp a taphonomic hypothesis is proposed to explain the dichotomy between the findings of this study and the pollen record of the site

seismites an attempt at critical analysis and classification abstract the main types of seismites are reviewed following the proposed classification and are illustrated by our own case studies the large variety of seismites depends on the sedimentologic hydrodynamic and diagenetic characters of the deposits subject to seismic shocks on a given site generally different types of seismites cane be related to the same seismic event these peculiar but widespread sedimentary structures are not always univocal and may often be related to different causes therefore the structures discussed must necessarily be placed in a detailed geological context

late ordovician brachiopod distribution and ecospace partitioning in the tvaren crater system sweden abstract patterns of distribution and ecospace utilization of late ordovician brachiopods in a recently formed contemporary meteorite crater are described and analyzed rhynchonelliformean brachiopod communities dominated by a wide range of orthides and strophomenides colonized the newly formed crater at the crater rim communities were established early on although the crater depression was not inhabited until deposition of the upper third of the remaining crater fill the crater formed a protected but restricted microenvironment where sediments four times the thickness of the nearby basinal succession accumulated within this narrow space environments varied from shallow water to deeper waters about 200 m in depth and from well oxygenated to hypoxic such varied environments generated a rough ecological landscape facilitating niche partitioning across a relatively small geographic area analysis of the guild structure of the fauna permits explanation of a local biodiversity hotspot in otherwise low diversity strata elsewhere in the scandinavian region the tvaren impact event had an important palaeobiologic effect upon the fossil record as it served as a local pump and reservoir for biodiversity moreover the development of new community types and narrowly defined niches helped further drive both and biodiversity during a critical phase of the great ordovician biodiversification event

recognition of trigger mechanisms for soft sediment deformation in the pleistocene lacustrine deposits of the santʻarcangelo basin southern italy seismic shock vs overloading abstract the lacustrine deposits of the san lorenzo cycle belong to the infill succession of the sant arcangelo basin a pliocene to pleistocene satellite basin developed close to the front of the south apennines thrust belt the lower to middle pleistocene lacustrine succession is made up of siltstone and claystone interbedded with sandstone carbonate and volcaniclastic beds arranged in fining upward sequences the upper to middle part about 50 m thick of the succession about 200 m thick has been investigated in detail in the depocentral sector of the lacustrine basin here soft sediment deformation structures occur in fine grained sandstone and claystone alternations and show a wide morphological variability deformed laminations slumps load structures large vertical water escape structures and neptunian dykes their formation occurred during and after sedimentation with different mechanisms of deformation some structures are related to liquefaction and fluidization processes viscous fluid behaviour while others occurred when sediment had already undergone lithification and its behaviour was plastic and or brittle facies analysis and detailed morphologic study of the soft sediment deformation structures indicate that the main trigger agents for deformation were seismic shocks and overloading induced by sudden deposition of coarser sediments on clays due to the arrival of density currents thus the soft sediment deformation structures provide a continuous record of the tectonic and sedimentary processes that acted in the lacustrine basin from sedimentation until diagenesis

pennsylvanian sea level cycles nutrient availability and brachiopod paleoecology abstract as with modern organisms the spatial and temporal distribution of fossil communities was controlled by both the physical setting in which the organisms lived and by the organisms physiology and interactions by studying the sedimentological and geochemical context of fossil communities it is possible to assess the relative importance of the physical setting and the organisms physiology comparison of pennsylvanian brachiopod associations with changing sedimentological context water depth facies and nutrient availability indicates that body size is a function of water depth and nutrient availability for most spire bearing athyridids and spiriferids brachiopods but rarely for productid brachiopods spire bearing brachiopods dominate the associations in high nutrient settings and productid brachiopods dominate the associations in low nutrient settings this difference suggests that physiological differences between brachiopod orders such as lophophore filtering efficiency play an important role in controlling their distribution

palaeoecology and sedimentology of carboniferous glacial and post glacial successions in the paganzo and rio blanco basins of northwestern argentina

pollen taphonomy and airfall sedimentation in a tropical cave the west mouth of the great cave of niah in sarawak malaysian borneo abstract this paper investigates the taphonomy of predominantly biogenic sediments and pollen in the key archaeological site in the west mouth of the great cave of niah sarawak strong spatial patterning of sediments and pollen were found with a zonation related to distance into the cave near the cave mouth sedimentation is silty and derived from waters running down the cliff outside the cave with leaves from external vegetation pollen assemblages are similar to forest floor samples outside the cave and thus are of airfall or wash origin in the interior of the west mouth sedimentation is highly organic and composed largely of bird droppings pollen assemblages in the interior are strongly but regularly biased with over representation of mangrove and riverine taxa resulting from the recruitment of pollen by bats and swiftlets foraging preferentially in these zones over 7 and over 2 km from the cave respectively the significance of these findings for the understanding of humid tropical cave sequences and particularly for the current reassessment of niah cave is discussed

the late pleistocene duoi u oi cave in northern vietnam palaeontology sedimentology taphonomy and palaeoenvironments this paper describes new fossil materials recovered at the duoi u oi site in december 2003 by a vietnamese french japanese team the duoi u oi cave is located in man duc village 25 km of hoabinh city in northern vietnam it belongs to a karstic network developed in a dark grey micritic marine limestone dated from the lower to the middle triassic the sedimentary fill produced a rich mammalian fauna essentially composed of isolated teeth of middle to large sized mammals artiodactyla perissodactyla proboscidea carnivora rodentia primates and characteristic of late pleistocene the results of the duoi u oi fieldwork are of great interest for the following reasons 1 the biochronological age of the fauna is consistent with 230 th 234 u 238 u dating from the calcitic floors 6673 ka the duoi u oi fauna is thus the oldest well dated modern fauna known for the southeast asian mainland 2 in terms of sedimentology the analysis of the formation of the fossiliferous breccia and that of the processes of deposits shows a close relation between the karstic deposits inside the cave and the deposits in the alluvial terraces the observation of three levels of alluvial terraces associated with three caves situated at 62 10 and 3 m above the present alluvial plain suggests that exokarstic and endokarstic sediments evolved together 3 in terms of palaeobiogeography duoi u oi is the continental fauna showing the strongest resemblance with the late pleistocene faunas from indonesian islands punung gunung dawung lida ajer sibrambang and djambu caves this implies that at the time of duoi u oi ca 70 ka the sundaland was mainly characterised by faunas of modern aspect 4 the analysis of major taphonomic factors that led to the mammal assemblage reveals a combination of selective agents selective role of predators and porcupines selective destruction of age classes for some species selective preservation of fossils due to the deposition processes in the karstic network which contribute to the poor representation of the diversity of the fauna no arguments show that humans present at duoi u oi might have a possible role in the taphonomic process 5 the palaeoenvironmental reconstruction based on the composition of the faunal assemblage suggests a forested area and some open habitats under warm and humid conditions

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

compositional changes in sigmoidal carbonate clinoforms late tithonian eastern sardinia italy insights from quantitative microfacies analyses quantitative analysis of sediment composition was performed on a kilometre wide section of upper tithonian low relief up to 70 m gently inclined 3 to 15 sigmoidal carbonate clinoforms eastern sardinia to identify changes in sediment composition along the slope and across the studied succession these changes may reflect modifications of the carbonate factory and of processes responsible for sediment transport point count analysis of carbonate microfacies q mode r mode cluster analysis and spearman s rank provided a composition based classification of microfacies and highlighted relationships among sediment components the studied clinoforms are mainly composed of non skeletal grains 70 such as peloids and lithoclasts together with micrite and cements and only a limited contribution from coated grains 2 among skeletal grains 28 the greatest contribution derives from a coral stromatoporoid encruster reef that provided 15 of the components crinoids brachiopods and other along slope thriving biota provided nearly 5 of the allochems whilst fragments of molluscs gastropods bivalves and diceratids from the backreef sourced another 2 the contribution of platform interior biota is negligible 1 the association of composition based facies varies along the slope the upper slope beds consist of coral stromatoporoid grainstone to rudstone the middle slope deposits are dominated by encruster lithoclast grainstone and packstone at the lower slope peloidal lithoclastic packstone as well as brachiopod crinoidal wackestone prevail also the association of skeletal grains changes along the slope the encruster frame builder association typifies the upper slope whilst encrusters characterize the middle slope sediments in the lower slope encrusters are equally represented as the brachiopod crinoid association along slope compositional changes evidence a scarce downslope transport of frame builders and a progressive enrichment in along slope thriving biota quantitative analysis of microfacies allowed the sigmoidal clinoforms to be grouped into six sets each set gathers sigmoids with a similar sediment composition coated grains are dominant in the first set whilst they are lacking in the overlying sets reflecting a change in the carbonate factory other major compositional changes among the sets concern the relative amounts of peloids micrite frame builders corals and stromatoporoids and encrusters the contribution of peloids varies inversely to that of cements and micrite as evidenced in the third and fifth sets which respectively record the highest occurrence of peloids or cement and micrite variations in the amount of frame builders and encrusters are instead non linear high percentages of both frame builders and encrusters as recorded in the second and fifth sets are related to low amounts of peloids and lithoclasts that probably reflect episodes of reduced background sedimentation this study demonstrates that quantitative analysis of carbonate microfacies represents a powerful tool that can improve the reconstruction of the stacking pattern in carbonate slope successions both in outcrop and in subsurface settings

radiocarbon calibration curve spanning 0 to 50 000 years bp based on paired 230 th 234 u 238 u and 14 c dates on pristine corals abstract radiocarbon dating is the most widely used dating technique in the world recent advances in accelerator mass spectrometry ams and sample preparation techniques have reduced the sample size requirements by a factor of 1000 and decreased the measurement time from weeks to minutes today it is estimated that more than 90 percent of all measurements made on accelerator mass spectrometers are for radiocarbon age dates the production of 14 c in the atmosphere varies through time due to changes in the earth s geomagnetic field intensity and in its concentration which is regulated by the carbon cycle as a result of these two variables a radiocarbon age is not equivalent to a calendar age four decades of joint research by the dendrochronology and radiocarbon communities have produced a radiocarbon calibration data set of remarkable precision and accuracy extending from the present to approximately 12 000 calendar years before present this paper presents high precision paired 230 th 234 u 238 u and 14 c age determinations on pristine coral samples that enable us to extend the radiocarbon calibration curve from 12 000 to 50 000 years before present we developed a statistical model to properly estimate sample age conversion from radiocarbon years to calendar years taking full account of combined errors in input ages and calibration uncertainties our radiocarbon calibration program is publicly accessible at http www radiocarbon ldeo columbia edu along with full documentation of the samples data and our statistical calibration model

recurrence pattern of holocene earthquakes along the dead sea transform revealed by varve counting and radiocarbon dating of lacustrine sediments abstract a high resolution holocene seismic history of the dead sea transform dst is established from laminated sedimentary cores recovered at the shores of the dead sea radiocarbon dating and annual laminae counting yield excellent agreement between disturbed sedimentary structures identified as seismites and the historical earthquake record all recent and historical strong events of the area were identified including the major earthquakes of a d 1927 1837 1212 1033 749 and 31 b c the total of 53 seismites recognized along the entire holocene profile indicate varying recurrence intervals of seismic activity between a few and 1000 years with a conspicuous minimum rate at 2100 31 b c and a noticeable maximum during the past six to eight centuries most of the epicenters of the correlated earthquakes are situated very close to the dead sea within 150 km or up to 400 km north of it along the dst between 1000 b c and a d 1063 and from a d 1600 to recent time the epicenters are all located on the northern segment of the dst whereas prior to 1000 b c and between a d 1000 and 1600 they appear to scatter along several segments of the dst we establish how the local intensity exerts a control on the formation of seismites at historically estimated intensities greater than vii all well documented earthquakes are correlated whereas at intensities smaller than vi none are matching the periods with enhanced earthquake rate along the dst correlate with those along the north anatolian fault as opposed to the intervening east anatolian fault this may indicate some elastic coupling on plate boundary scale that may also underlie escape and extrusion tectonics typical of continental collision

site formation processes in caves the holocene sediments of the haua fteah cyrenaica libya caves have yielded some of the most globally important archaeological sequences but often their interpretation has suffered from assumptions about cave sedimentary processes caves contain distinctive sedimentary environments this has major implications for the understanding of contained archaeological materials this paper describes and analyses the holocene sediments in the haua fteah a sequence regarded as essentially continuous by the original excavator 50 years after it was first excavated the haua s epipalaeolithic to post classical chronological range and rich finds make it still the key holocene archaeological site in north africa the reassessment shows however that the sequence is strongly discontinuous and this has major implications for the reinterpretation of the site as the highly resolved archaeological record is thus likely to reflect a series of brief occupations rather than continuous human activity as with many caves the sedimentary record in the haua fteah is an extremely sensitive indicator of environments and processes in the wider landscape secure understanding of sedimentary process from analysis of the highly individual records found in caves is essential for full understanding of their contained archaeology

the cultural antiquity of rainforests human plant associations during the mid late holocene in the interior highlands of sarawak malaysian borneo 2015 elsevier ltd and inqua rainforests are often described as the world s last virgin landscapes however hunter gatherers may have been modifying these environments for over 50 000 years despite this the antiquity of early tropical forest exploitation by hunter gathers and the transition to farming are still poorly understood today globalization drives deforestation of rainforests at an unprecedented rate the forest the lives of its present day inhabitants and the archaeological evidence for their history are unlikely to survive for much longer in their present form the cultured rainforest project an interdisciplinary project involving anthropologists archaeologists and palaeoecologists was set up in 2007 to investigate the long term and present day interactions between people and the rainforest in the kelabit highlands of central borneo so as to better understand past and present agricultural and hunter gatherer lifestyles and landscapes this paper examines the environmental evidence used to investigate initial signs of plant exploitation and the transition to agriculture as well as to understand the wider significance of past plants in a changing cultural landscape results have shown that two pronounced cultural waves of human plant interactions took place in the kelabit highlands during the late holocene although tentative marks may be present on the landscape ca 7000 6000 years ago the first pronounced wave of human plant interaction begins from at least 3000 cal bp it seems to correspond with the appearance of stone mounds and open air sites recorded in the archaeological record the sago palm eugeissona plays an important role during this period a second wave of cultural activity particularly in the last 450 years is recorded in the southern kelabit highlands and is marked by rice becoming important this may be linked to the construction of a wide range of different megaliths and earthworks due to its inferred association with wealth and status in prehistoric and historic periods it is perhaps also linked to a rise in trade between the coastal regions and highlands

soft sediment deformation structures interpreted as seismites in lacustrine sediments of the prebetic zone se spain and their potential use as indicators of earthquake magnitudes during the late miocene lacustrine formations of late miocene age in the prebetic area se spain show several types of deformational structures that are interpreted as seismites they are present in both marginal and deep lacustrine facies seismites formed in marginal lake environments comprise sand dikes pillows and intruded and fractured gravels in deep lacustrine facies the seismites are represented by pseudonodules mushroom like silts protruding into laminites mixed layers disturbed varved lamination and loop bedding the measured orientations of these structures are consistent with the orientations of the main faults limiting the basins showing that their origin is clearly related to the tectonic stress field that prevailed in the region during the late miocene the magnitudes of the earthquakes that deformed the sediments have been estimated after published data from both ancient and recent lake deposits accumulated in tectonic active regions elsewhere a rank of earthquake magnitudes with two end members i e the lowest magnitudes recorded by loop bedding in laminites and the highest magnitudes represented by intruded and fractured gravels is proposed

interstratal dewatering origin for polygonal patterns of sand filled cracks a case study from late proterozoic metasediments of islay scotland sand filled cracks from the lower fine grained quartzite of dalradian late proterozoic age on the island of islay western scotland may be divided into two main types both of which form orthogonal and non orthogonal closed patterns on bedding surfaces type 1 cracks are short and lenticular in cross section contain sand which had been injected downwards and are found on the bottoms of cross laminated sandstone beds type 2 cracks cut several beds and preserve evidence of upward flow of water saturated sand both types of crack developed through the interstratal intrusion of water saturated sand into shrinkage cracks in mud or muddy sand not as previously thought as a result of sub aerial desiccation or sub aqueous cracking of the sediment surface synaeresis these cracks likely resulted from layer parallel contraction caused by compaction of mudstone layers during burial seismic shock may have provided the trigger for the preferential development of polygonal crack patterns in these layers instead of the more usual small scale dewatering structures from a detailed comparison with published descriptions of filled cracks from a number of different geological environments it is concluded that interstratal cracking is a mechanism which rivals sub aerial desiccation in importance and is more common in the geological record than is currently realized

biomass burning in indonesia and papua new guinea natural and human induced fire events in the fossil record abstract microscopic charcoal preserved in sediments from ten wetlands in the indonesian and papua new guinea region provide a proxy record of regional fire events during the last 20 000 years two periods of high regional charcoal frequency are encountered during the last glacial transition 17 000 9000 years b p and the middle to late holocene 5000 years b p to the present despite the presence of humans in the region throughout the last 20 000 years there is no suggestion that on a regional spatial scale fire frequencies were solely related to changing subsistence patterns of the human population pollen data from these same sites suggest that during times of high charcoal the rate at which vegetation changes represented by the fossil pollen spectra also increases high climate variability may promote a greater community turnover rate and in turn a more fire susceptible forest community rapid climate change and high variability during the last glacial transition and intensification of el nino related climate variability during the middle to late holocene may have been important mechanisms for promoting fire in rainforest environments and maintaining diversity of tropical rain forests

the vegetation and climate at the last glaciation on the emerged continental shelf of the south china sea studies on the dispersal mechanism and source areas of pollen from hemipelagic sediments recovered from the continental slopes of the south china sea scs reveal that vegetation existed on the exposed shelves at the last glacial maximum lgm and the latter part of the marine isotope stage 3 at the low sea level stand artemisiadominated grassland covered the northern continental shelf and tropical lowland rainforest and mangroves grew on the southern shelf sunda land consequently the climate in the northern scs must have been much colder and drier during the last glacial period compared to the present sunda land experienced only a marginally lower temperature but was not drier than today the enhanced contrast between the northern and southern parts of the scs in vegetation and climate during the lgm may be ascribed at least partly to the strengthening of winter monsoon during the last glacial period 2000 elsevier science b v all rights reserved