plant community ecology and climate on an upland volcanic landscape during the early eocene climatic optimum mcabee fossil beds british columbia canada abstract the mcabee fossil beds in south central british columbia canada provide a record of forest ecosystems within a volcanically active upland landscape during the early eocene climatic optimum eeco to assess plant community ecology and climate within this environment palynology and census style macrofossil collections were investigated from two shale horizons separated in time by likely 103 104 years an ensemble of leaf physiognomic estimates indicates a persistent warm mean annual temperature mat 10 12 c and mesic mean annual precipitation 1000 mm yr 1 climate between the horizons the plant community was similar in both horizons comprising angiosperms e g ulmus fagus alnus betula and carya and gymnosperms e g metasequoia pinus picea and larix plant diversity and the distribution of dicot leaf mass per area ma values were consistent between the two horizons despite intervals of varying tuff thickness and frequency between the horizons differences in macrofossil abundances of ulmus fagus and pinus and a lack of such differences in their respective pollen abundances might be explained by local patch dynamics influenced by spatial heterogeneity resulting from topographic diversity and disturbance ma estimates suggest dicots were predominately deciduous and the distribution of ma is similar to a modern forest in panama influenced by seasonal precipitation the diversity of dicots at mcabee despite relatively lower mean annual temperatures is comparable to fossil plant quarries of similar volume from early eocene sites in patagonia e g laguna del hunco and the denver basin with relatively warmer mats 17 25 c this is best explained by a combination of predominately frost free winters high productivity and an abiotic environment characterized by spatial heterogeneity and high rates of change the sampled paleofloras of this study showcase an eeco plant community likely representing an ecological solution to volcanic disturbance over millennial time scales

magnitude and variation in the contribution of bank erosion to the suspended sediment load of the river severn uk the wide range of studies describing the role of bank erosion in fluvial sediment supply have mostly lumped amounts of bank erosion into coarse temporal units such as years this paper investigates sediment yields from individual bank erosion events within the upper river severn uk basin area 380 km2 manual erosion pins and photo electronic erosion pins were used to estimate bank erosion and turbidity meters were used to determine suspended sediment transport at the annual time scale the silt clay fraction of bank derived sediment accounted for an equivalent of 17 per cent of the suspended load increasing to an average of 38 per cent at the monthly timescale and then to an average of 64 per cent at the event timescale this research highlighted that for an upland catchment bank erosion was an important supply of suspended sediment and that for some flood events bank erosion can supply more sediment than is transported 1997 john wiley sons ltd

terrestrial climate evolution in the southwest pacific over the past 30 million years abstract a reconstruction of terrestrial temperature and precipitation for the new zealand landmass over the past 30 million years is produced using pollen data from 2000 samples lodged in the new zealand fossil record electronic database and modern climate data of nearest living relatives the reconstruction reveals a warming trend through the late oligocene to early miocene peak warmth in the middle miocene and stepwise cooling through the late neogene whereas the regional signal in our reconstruction includes a 5 10 northward tectonic drift as well as an increase in high altitude biomes due to late neogene and pliocene uplift of the southern alps the pattern mimics inferred changes in global ice extent which suggests that global drivers played a major role in shaping local vegetation importantly seasonal temperature estimates indicate low seasonality during the middle miocene and that subsequent neogene cooling was largely due to cooler winters we suggest that this may reflect increased subantarctic influence on new zealand vegetation as the climate cooled

estimating paleoatmospheric pco2 during the early eocene climatic optimum from stomatal frequency of ginkgo okanagan highlands british columbia canada abstract estimates of p co 2 for the early paleogene vary widely from near modern day levels to an order of magnitude greater based on various proxy measures resolving the relationship between climate and p co 2 during this globally warm period is a key task in understanding climate dynamics in a warmer world here we use the stomatal frequency of fossil ginkgo adiantoides from the okanagan highlands of british columbia canada to estimate p co 2 during the early eocene climatic optimum eeco the interval of peak warmth in the cenozoic we also examine a dataset of modern ginkgo biloba leaves to critically assess the accuracy and precision of stomatal frequency as a proxy indicator of p co 2 early eocene fossil g adiantoides has significantly lower stomatal frequency than modern g biloba suggesting p co 2 levels 2 modern pre industrial values this result is in contrast to earlier studies using stomatal frequency of ginkgo that indicated near modern day levels of p co 2 in the early paleogene though not including samples from the eeco we also find that levels of p co 2 as indicated by stomatal frequency are correlated with trends in climate mean annual temperature over time at the falkland fossil locality suggesting that climate and p co 2 were coupled during the eeco hyperthermal

geomorphic changes in a complex gully system measured from sequential digital elevation models and implications for management high resolution digital elevation models dems were derived from sequential aerial photography of an active uvio mass movement gully complex in new zealand s north island east coast region to measure geomorphic changes over approximately one year the gully showed a complex behaviour combining uvial and mass movement erosion deposition and reworking of materials stored in an active debris fan during the measurement period 5200 1700 m3 of material were eroded from the 8 7 ha gully complex and 670 180 m3 from the 0 8 ha depositional fan giving a total of 5870 1710 m3 for the entire gully complex fan system the results provide a high resolution description of gully behaviour over a short time period and also demonstrate that mass movement slumping and debris ows accounted for almost 90 per cent 4660 200 m3 of the sediment generated this erosional response is described in terms of gully evolution by comparing the gully complex to other systems in the region in various stages of development the effect of gully evolution on geomorphic coupling between the gully complex and channel system is described and coupling is also shown to vary with the magnitude and frequency of rainfall events from a land management perspective the success of strategies such as tree planting to mitigate against gully erosion depends on the stage of gully development particularly on whether or not mass movement erosion has begun in contrast to gully rehabilitation efforts elsewhere basin wide afforestation in the early stages of gully incision is favoured over riparian planting given that mass movement assisted by excessive groundwater pressure is the main process leading to uncontrollable gully expansion to protect land effectively against continuing gully erosion of headwater catchments and resulting downstream aggradation it is necessary for land managers to understand the spatial and temporal variability of gully development fully so that mitigation efforts can be targeted appropriately copyright 2003 john wiley sons ltd

eocene paleo physiography and drainage directions southern interior plateau british columbia a map of reconstructed eocene physiography and drainage directions is presented for the southern interior plateau region british columbia south of 53 n eocene landforms are inferred from the distribution and depositional paleoenvironment of eocene rocks and from crosscutting relationships between regional scale geomorphology and bedrock geology of known age eocene drainage directions are inferred from physiography relief and base level elevations of the sub eocene unconformity and the documented distribution provenance and paleocurrents of early cenozoic fluvial sediments the eocene landscape of the southern interior plateau resembled its modern counterpart with highlands plains and deeply incised drainages except regional drainage was to the north an anabranching valley system trending west and northwest from quesnel and shuswap highlands across the cariboo plateau to the fraser river valley contained north flowing streams from eocene to early quaternary time other valleys dating back at least to middle eocene time include the north thompson valley south of clearwater thompson valley from kamloops to spences bridge the valley containing nicola lake bridge river valley and okanagan lake valley during the early cenozoic highlands existed where the coast mountains are today southward drainage along the modern fraser chilcotin and thompson river valleys was established after the late miocene

high co2 increases the freezing sensitivity of plants implications for paleoclimatic reconstructions from fossil floras reconstructions of coldest month mean temperature cmmt in the geologic past are important for understanding the dynamics of the climate system operating at that time a common method for estimating cmmt involves applying the climatic tolerances of modern plant species to close analogues in the fossil record the so called nearest living relative nlr approach here we show that the leaves of seven modern species commonly used as nlrs to reconstruct cmmt from the fossil record freeze at warmer temperatures when grown at high co2 800 vs 400 ppmv this co2 effect was found across all tested plant groups including palms taxodiaceous conifers and two southern hemisphere evergreen species this pervasive response indicates that many nlr derived estimates of cmmt for times of high co2 should be adjusted by at least 11 5 to 13 8c a revision of cmmt estimates toward warmer values further increases the disparity in continental interiors between cmmt indicators from the fossil record and the colder predictions from general circulation models

dating the culmination of river aggradation at the end of the last glaciation using distal tephra compositions eastern north island new zealand an extensive terrace waipaoa 1 that can be traced for about 29 km in the waipaoa valley eastern north island new zealand is underlain by at least 10 m of coarse aggradational river gravels terrace cover beds contain tephras erupted from central north island volcanoes and these provide minimum ages for the underlying gravels tephra or tephric layers occurring in the lower cover beds were investigated at five sites using a combination of stratigraphy mineralogy and the major element composition of glass shards together with discriminant function analysis dfa the basal tephra is identified as the ca 14 700 14c years old ca 17 700 cal years b p rerewhakaaitu tephra erupted from okataina volcanic centre using the stratigraphic relationship of rerewhakaaitu tephra the end of aggradation is dated at ca 15 000 14c years ca 18 000 cal years correlation with aggradational terraces elsewhere in north island and northern south island indicates that aggradation ended at the same time over a wide area and confirms a climatic origin for the terraces subsequent downcutting was apparently rapid because rerewhakaaitu tephra also occurs at the base of cover beds on a ca 15 m lower terrace the downcutting represents a major change in river dynamics and is most likely the response to climatic change and the resultant upper catchment landscape stability

channel change bankfull and effective discharges on a vertically accreting meandering gravel bed river along the lower reaches of the waipaoa river new zealand cross section survey data indicate there was a 23 per cent decrease in bankfull width and a 22 per cent reduction in channel cross section area between 1948 and 2000 as the channel responded to increased inputs of fine suspended sediment following deforestation of the headwaters in late c19 and early c20 we determined the bankfull discharge within a 39 km long reach by routing known discharges through the one dimensional mike 11 flow model the model runs suggest that the bankfull discharge varies between 800 and 2300 m3 s 1 and that the average recurrence interval is 4 2 years on the annual maximum series by contrast the effective flow 360 m3 s 1 is equaled or exceeded three times a year the variability in bankfull discharge arises because the banks tend to be lower in places where flood flows are constricted than in reaches where overbank flow is dispersed over a wide area and because scour has counteracted aggradation in some locations there is no downstream variation in shields stress or in relative shear stress within the study reach bankfull shear stress is on average five times greater than the shear stress required to initiate motion at the effective discharge it is more than twice the threshold value the effective discharge probably has more relevance than the bankfull discharge to the overall picture of sediment movement in the lower reaches of the waipaoa river but because width is constrained by the stability and resistance of the bank material to erosion during high flows that also scour the bed the overall channel geometry is likely determined by discharges at or near bankfull copyright 2006 john wiley sons ltd

modelling of the retreat process of composite riverbank in the jingjiang reach using the improved bstem bank retreat in the jingjiang reach is closely related not only to the near bank intensity of fluvial erosion but also to the composition and mechanical properties of bank soils therefore it is necessary to correctly simulate bank retreat to determine the characteristics of fluvial processes in the jingjiang reach the current version of bstem 5 4 was improved to predict riverbank retreat by inputting a dynamic water table and calculating the approximation of the distribution of dynamic pore water pressure in the soil near the river bank face and considering the depositional form of the failed blocks which is assumedly based on a triangular distribution with the slope approximately equalling the stable submerged bank slope and half of collapsed volume deposited in the bank toe region the degrees of riverbank stability at jing34 were calculated using the improved bstem the results indicate the following trends i the degrees of riverbank stability were high during the dry season and the rising stage which led to minimal bank failure and ii the stability degrees were low during the flood season and the recession stage with the events of bank collapse occurring frequently which belonged to a stage of intensive bank erosion considering the effects of bank toe erosion water table lag and the depositional form of the collapsed bank soil the bank retreat process was simulated at the right riverbank of jing34 the model predicted results exhibit close agreement with the measured data including the total bank retreat width and the collapsed bank profile a sensitivity analysis was conducted to determine the quantitative effects of toe erosion and water table lag on the degree of bank stability the calculated results for toe erosion indicate that the amount of toe erosion was largest during the flood season which was a primary reason for bank failure the influence of water table lag on the degree of stability demonstrates that water table lag was an important cause of bank failure during the recession stage

depositional setting fossil flora and paleoenvironment of the early eocene falkland site okanagan highlands british columbia the fossil flora and depositional setting of the early eocene falkland site in the southern interior of british columbia canada is reported in detail for the first time using a census sampling approach the falkland site is part of the series of okanagan highlands fossil localities in british columbia and washington state that represent relatively cool upland environments within the context of the greenhouse world of the early eocene providing microthermal mean annual temperature mat 13 c climatic conditions for the establishment of cool adapted plants geographically adjacent to subtropical elements from lowland floras plant community composition of the falkland flora is most similar to the republic washington and mcabee british columbia floras based on high sorenson similarity coefficients together forming a southern cluster of okanagan highlands sites the site is a lacustrine deposit that formed in a volcanically active landscape paleoclimate reconstructions based on leaf physiognomy

downstream fining in a rapidly aggrading gravel bed river downstream changes in particle size that occur in the waipaoa river a 104 km long gravel bed river in which rapid aggradation in the historic post 1800 period was triggered by the conversion of native forest to pasture are summarized in this paper the textural data presented are unique for a field situation not only because of the spatial resolution and extent of the sampling program but also because they provide information about the pattern of fining at different points in time they are supported by equally comprehensive topographic survey data from which local rates of aggradation can be derived despite variability induced by lateral sediment inputs there is an essentially continuous pattern of fining along the entire length of the river fining occurs in both the fine and coarse size fractions of the bed material the highest rates of fining occur in the larger percentiles of the subsurface bed material and in the surface bed material downstream fining in the waipaoa river appears to be a response to changes in flow hydraulics that are regulated by the concave configuration of the long profile the fining gradient developed rapidly in 45 years it does not appear to be influenced by the rate of aggradation nor the overall rate of sediment supply to the channel system because in the short term aggradation has a negligible impact on the inherited form of the long profile

the coexistence approach a method for quantitative reconstructions of tertiary terrestrial palaeoclimate data using plant fossils abstract the coexistence approach is introduced as a method for quantitative terrestrial palaeoclimate reconstructions in the tertiary it is based on the assumption that tertiary plant taxa have similar climatic requirements to their nearest living relatives the aim of the coexistence approach is to find for a given fossil flora and a given climate parameter the climatic interval in which all nearest living relatives of the fossil flora can coexist for this purpose we have developed a data base climbot containing for over 800 tertiary plant taxa the nearest living relatives and their climatic requirements and an algorithm for analysis climst for all types of fossil floras the coexistence approach thus allows the rapid quantitative reconstruction of 10 different climate parameters including the mean annual temperature temperature of the warmest month temperature of the coldest month mean annual precipitation maximum monthly precipitation minimum monthly precipitation precipitation of the warmest month relative humidity potential evaporation as well as the ratio of mean annual precipitation over potential evaporation the reliability and resolution of the coexistence approach are tested with various techniques and proved to be reasonably good for instance the resolution with respect to the mean annual temperature can be up to 1 c applications to various modern and fossil floras are illustrated and the advantages and disadvantages of the coexistence approach are discussed

evidence for orbital forcing of dust accumulation during the early paleogene greenhouse the accumulation of wind blown eolian dust in deep sea sediments reflects the aridity humidity conditions of the continental region supplying the dust as well as the gustiness of the climate system detailed studies of pleistocene glacial interglacial dust fluxes suggest changes in accumulation rates corresponding to orbital variations in solar insolation milankovitch cycles while the orbital cycles found in sedimentary archives of the pleistocene are intricately related to glacial growth and decay similar global orbital signals recognized in deep sea sediments of early paleogene age the last major greenhouse interval 65 45 million years ago could not have been linked to the waxing and waning of large ice sheets thus orbital signals recorded in early paleogene sediments must reflect some other climate response to changes in solar insolation to explore the potential connection between orbital forcing and the climate processes that control dust accumulation we generated a high resolution dust record for 58 myr old sediments from shatsky rise odp site 1209 paleolatitude 15 n 20 n the dust accumulation data provide the first evidence of a correlation between dust flux to the deep sea and orbital cyclicity during the early paleogene indicating dust supply responded to insolation forcing during the last major interval of greenhouse climate furthermore the relative amplitude of the dust flux response during the early paleogene greenhouse was comparable to that during icehouse climates thus subtle variations in solar insolation driven by changes in earth s orbit about the sun may have had a similar impact on climate during intervals of overall warmth as they did during glacial interglacial states

3 d seismic structure of the source area of the 1993 latur india earthquake and its implications for rupture nucleations abstract the latur earthquake mw 6 1 of 29 september 1993 is a rare stable continental region scr earthquake that occurred on a previously unknown blind fault in this study we determined detailed three dimensional 3 d p and s wave velocity vp vs and poisson s ratio structures by inverting the first p and s wave high quality arrival time data from 142 aftershocks that were recorded by a network of temporary seismic stations the source zone of the latur earthquake shows strong lateral heterogeneities in vp vs and structures extending in a volume of about 90 90 15 km3 the mainshock occurred within but near the boundary of a low vp high vs and low zone this suggests that the structural asperities at the mainshock hypocenter are associated with a partially fluid saturated fractured rock in a previously unknown source zone with intersecting fault surfaces this might have triggered the 1993 latur mainshock and its aftershock sequence our results are in good agreement with other geophysical studies that suggest high conductivity and high concentration of radiogenic helium gas beneath the source zone of the latur earthquake our study provides an additional evidence for the presence of fluid related anomaly at the hidden source zone of the latur earthquake in the scr and helps us understand the genesis of damaging earthquakes in the scr of the world

the post glacial downcutting history in the waihuka tributary of waipaoa river gisborne district implications for tectonics and landscape evolution in the hikurangi subduction margin new zealand abstract determining the spatial and temporal deliveries of sediment from the waipaoa river catchment in the post glacial period is a major goal of integrated source to sink landscape evolution studies in the region in a 2 2 km long section of the waihuka tributary 217 km 2 of the waipaoa river 2150 km 2 in eastern north island new zealand a sequence of at least ten fluvial terraces and abandoned meanders up to 45 m above the present river records rates and times of post glacial downcutting dateable organic and tephra horizons in the terrace and meander infill stratigraphy indicate that downcutting at this location on the waihuka tributary was dominated by a short lived event in the early holocene from 10 8 ka bp when as much as half of the downcutting was accomplished in only 10 15 of post glacial time the large downcutting event is interpreted to record the passing of a succession of major knickpoints or a knickzone through this tributary the initiation of knickpoint retreat in the catchment was primarily a consequence of reduction in sediment supply at the end of mis 2 based on the timing of rapid downcutting in the waipaoa river mainstem we estimate that the rate of knickpoint retreat along the waihuka tributary was about 2 km kyr in the period before and after rapid downcutting in the waihuka tributary modest incision rates averaging 1 2 mm yr probably represent the regional tectonic uplift rate

microseismicity and tectonics at the indian pacific plate boundary south east wellington province new zealand summary the seismicity structure and tectonics of part of the north island plate boundary have been studied by means of a microearthquake traverse in the south eastern part of wellington province the short term microseismicity observed in this survey is similar to the long term macroseismicity about 200 microearthquakes have been located in a four week survey microearthquakes occur mostly within the depth range 20 40 km defining a band of activity which is fairly continuous and uniform along the strike direction of the subducted pacific plate a break in seismic activity is observed below 40 km depth however in vertical sections along the direction of the dip of the subducted plate systematic differences in microearthquake activity are observed between the supposedly locked and unlocked regions of the subducted plate the sections show further how the foci deepen progressively towards the north west focal mechanisms of 115 well located microearthquakes are examined in relation to the structure and tectonics of the region the mechanisms are related to the plate interface geometry in a manner consistent with that found for other regions of plate convergence microearthquakes in the overriding plate are associated with thrust fault mechanisms while those in the subducted plate exhibit normal faulting the stress pattern is also consistent with the tectonics of the region the t axes of the normal fault mechanisms are parallel to the dip of the subducted plate whereas the p axes of the thrust fault mechanisms are nearly in the e w direction this is consistent with the suggestion that the plates are locked in the coastal part of the region in addition small but systematic differences in the thickness and dip of the benioff zone are observed in the sw the zone is about 5 km thinner and 6 less steep than in the ne on the landward side there is a bend in the benioff zone at 25 30 km depth the dip of the zone sharply increases below this depth where it enters the region of negative gravity anomaly

regional stratigraphy and structural setting of the kamloops group south central british columbia the kamloops group is redefined as an assemblage of lower to middle eocene volcanic and sedimentary rocks widespread in south central british columbia in the type area west of kamloops the basal

measurement of river bank and cliff erosion from sequential lidar and historical aerial photography abstract the methodology and errors involved in determining the meander migration rates and amount of sediment produced by river bank and cliff erosion over five decades along a 16 and 28 km reach of the waipaoa river new zealand are described the reach average meander migration rates 0 22 and 0 12 m a 1 respectively are low by international standards for rivers of comparable size suggesting considerable stability of the river planform the contribution of sediment from bank and cliff erosion 74 3 and 23 3 kt a 1 respectively to suspended sediment load is also low

a deterministic seismic hazard map of india and adjacent areas a seismic hazard map of the territory of india and adjacent areas has been prepared using a deterministic approach based on the computation of synthetic seismograms complete with all main phases the input data set consists of structural models seismogenic zones focal mechanisms and earthquake catalogues there are few probabilistic hazard maps available for the indian subcontinent however this is the first study aimed at producing a deterministic seismic hazard map for the indian region using realistic strong ground motion modelling with the knowledge of the physical process of earthquake generation the level of seismicity and wave propagation in anelastic media synthetic seismograms at a frequency of 1 hz have been generated at a regular grid of 0 2 x 0 2 by the modal summation technique the seismic hazard expressed in terms of maximum displacement d m a x maximum velocity v m a x and design ground acceleration dga has been extracted from the synthetic signals and mapped on a regular grid over the studied territory the estimated values of the peak ground acceleration are compared with the observed data available for the himalayan region and are found to be in agreement many parts of the himalayan region have dga values exceeding 0 6 g the epicentral areas of the great assam earthquakes of 1897 and 1950 in northeast india represent the maximum hazard with dga values reaching 1 2 1 3 g the peak velocity and displacement in the same region is estimated as 120 177 cm s 1 and 60 90 cm respectively

equability continentality and tertiary climate the crocodilian perspective the distributions of fossil crocodilians are used to examine north american continental paleoclimates for four time periods in the cenozoic control groups provide a qualitative means of examining the completeness of the record and thus the validity of crocodilian patterns by analogy with the range of the extant american alligator alligator mississippiensis the patterns imply that mid to high latitude continental interiors during the eocene and miocene did not undergo seasonal temperature extremes as great as those observed in such areas today this is compatible with the paleobotanical data during both the late oligocene and the pleistocene times of major glaciation crocodilians were restricted to more maritime localities

knickpoint initiation and distribution within fluvial networks 236 waterfalls in the waipaoa river north island new zealand if knickpoints transmit signals of base level fall in river networks then improvements in our understanding of their retreat rate and basin wide distribution helps constrain the transient response following perturbation many studies of knickpoint retreat focus on the response of trunk streams to base level fall here we examine the response of an entire fluvial network as recorded by 236 active knickpoints distributed within the waipaoa river on the north island of new zealand base level fall within the waipaoa catchment initiated 18 000 years ago in response to a climatically triggered and tectonically exacerbated pulse of incision using observations from field work aerial photo analysis and a digital elevation model dem we study the knickpoint positions within the network we find that 70 of the knickpoints are located at drainage areas between 1 10 5 m 2 and 1 10 6 m 2 and more than half are b1 km upstream of a large change in drainage area for the knickpoints b1 km upstream of large tributary junctions we find that the retreat distances were well correlated with the tributaries drainage areas in order to determine how a pulse of incision distributes itself throughout a fluvial network we develop two simple end member models and compare their behavior to the observed knickpoint distribution in the waipaoa in the first model we propose that a knickpoint initiated at the basin outlet retreats upstream and distributes the signal throughout the network at a rate that is a power law function of drainage area in the second model we propose that knickpoints form near a threshold drainage area below which channels cannot incise with the same efficiency as possible in downstream reaches though neither model addresses the along stream variability in substrate or knickpoint form the misfit between the modeled and the observed knickpoints along stream positions are surprisingly low b1 km 1 25 of the total stream length for knickpoints with drainage areas b1 10 6 m 2 large misfits up to 3 5 km are observed for knickpoints with present day drainage areas greater than 1 10 6 m 2 the large single step in channel elevation that characterizes knickpoints presently observed in tributaries of the waipaoa river may not characterize the base level fall signal that propagated through the trunk streams evidence for progressive rather than instantaneous incision in the trunk streams the knickpoints vicinities to tributary junctions and the equivalent success of the two end member models lead us to conclude that the present positions of the 236 observed knickpoints are largely a consequence of thresholds in channel incision at low drainage areas

ice sheet erosion and the stripping of tertiary regolith from baffin island eastern canadian arctic abstract the erosion of glaciated regions and concomitant changes in ice sheet dynamics through the pleistocene are poorly documented the baffin island landscape which has been shaped by the foxe sector of the laurentide ice sheet lis contains a variety of glacial and proximal glaciomarine sedimentary archives spanning the pleistocene we examine these records to better understand when tertiary regolith was stripped from beneath the foxe sector of the lis till on the interior plateaux of the island in areas with scoured bedrock have low chemical index of alteration cia values low meteoric 10 be 10 be met concentrations and clay mineralogy consistent with erosion from an unweathered bedrock source however in some areas in between fiord onset zones more weathered till is present containing considerably higher cia values high 10 be met concentrations and secondary clay mineral weathering products implying that the till has persisted on the landscape and weathered during successive glaciations using these weathering signatures we analyze the coastal glaciogenic deposits of the clyde foreland formation cff at two sites for evidence of tertiary regolith removal from the interior of baffin island by lis erosion provenance indicators within the cff demonstrate that pleistocene lis ice flow lines across baffin island have remained generally constant the oldest cff glaciogenic unit likely representing one of the first if not the first lis advances across baffin island had high 10 be met concentrations at the time of deposition consistent with extensive regolith erosion evidence of notably weathered sediment is absent in all younger units suggesting that tertiary regolith was likely largely stripped from the interior of the island by 1 6 0 2 ma

morphological evolution of a rural headwater stream after channelisation in recent decades stream valleys have been profoundly modified by the construction of weirs and dams and by channelisation channelisation modifies the morphology of streams and induces changes in their energy regime and sediment transport capacity these types of changes in the channel morphology have to be quantified to allow the implementation of management strategies to regulate sediment transfer however studies over an entire stream using historical comparisons remain scarce and the associated uncertainties have not yet been resolved in this study the sedimentary response to channelisation on a medium time scale 42 years of a french river known as the ligoire is investigated this river is the main channel of a small rural headwater catchment that has been channelised over 21 km we have used the historical cross sections before and after channelisation and the current ones and the objectives of this study were as follows 1 to develop a methodology of cross section superposition and the associated uncertainties 2 to quantify the erosion and aggradation processes in the bed and on the banks along the bed profile and 3 to calculate a sediment budget for the entire stream and determine the relative contributions of the banks and the streambed to this budget a comparison of the cross sections before and after the channelisation shows that the morphology of the stream has been completely altered the main channel length was reduced by 10 the bankfull width was increased on average by 63 and the slopes were smoothed a total of 60 000 m3 of sediments was excavated during the channelisation works our results indicate that erosion is the dominant process over 63 of its length the streambed was incised by 0 41 m on average and over 60 of its length the banks were eroded by 0 20 m on average the successive patterns of erosion and deposition along the stream are the result of the cumulative effects of channelisation and of the presence of weirs and artificial knickpoints in the ligoire channel the vertical uncertainty of the elevation of the historical cross section is an important parameter for controlling the areas and sediment budget values using monte carlo methods we found that 1000 sediment budgets from different profile shiftings are necessary to obtain a variation coefficient below 0 1 the overall mean stream sediment budget for the period 1970 2012 is 9358 412 m3 with 66 originating from the banks and 34 from the streambed relative to the ligoire watershed surface the stream sediment yield is 2 71 0 12 m3 km 2 y 1 the approach developed in this study is easily replicable and relatively cheap and provides an integrated quantified overview of the morphological adjustments after channelisation works on a stream

fossil biotas from the okanagan highlands southern british columbia and northeastern washington state climates and ecosystems across an eocene landscape the late early to early middle eocene okanagan highlands fossil sites spanning 1000 km north south northeastern washington state southern british columbia provide an opportunity to reconstruct biotic communities across a broad upland landscape during the warmest part of the cenozoic plant taxa from these fossil sites are characteristic of the modern eastern north american deciduous forest zone principally the mixed mesophytic forest but also include extinct taxa taxa known only from eastern asian mesothermal forests and a small number of taxa restricted to the present day north american west coast coniferous biome in this preliminary report paleoclimates and forest types are reconstructed using collections from republic in washington state usa and princeton quilchena falkland mcabee hat creek horsefly and driftwood canyon in british columbia canada both leaf margin analysis lma and quantitative bioclimatic analysis of identified nearest living relatives of megaflora indicated uppe

the okanagan highlands eocene biota environments and geological setting southern british columbia canada and northeastern washington usa climate change is a matter of concern to society decision makers and scientists as part of the debate about the science of climate change and in particular the extent to which current climate change is due to human activity or part of the natural variability of the global climate system earth scientists try to understand how climates have changed in the past and how past warming and cooling episodes affected the landscape and the plants and animals that occupied that landscape it is also clear from the fossil record that past climate change has played a role in the evolution of animal and plant lineages as well as plant and animal communities preserved in a series of lake deposits across northeastern washington state usa to smithers in north central british columbia canada the okanagan highlands fossil deposits preserve a record of a time when the world was much warmer than now because of a naturally enhanced greenhouse effect and the poles were ice free and supported great forests these s

paleoclimate and precipitation seasonality of the early eocene mcabee megaflora kamloops group british columbia early eocene fossil floras from british columbia are a rich resource for reconstructing western north american early cenozoic climate the best known of these floras reflect cooler mat 15 c upland forest communities in contrast to coeval mat 18 c forests in lowland western north american sites of particular interest is whether early eocene climates were monsoonal highly seasonal precipitation the mcabee site is a 52 9 0 83 ma 0 5 km outcrop of bedded lacustrine shale interbedded with volcanic ash in this report two historical megaflora collections that were collected independently from different stratigraphic levels and or laterally separated by 100 200 m in the 1980s university of saskatchewan and 2000s brandon university are investigated to i assess whether they represent the same leaf population ii assess whether a combined collection yields more precise climate estimates and iii reconstruct paleoclimate to assess the character of regional early eocene precipitation seas

systematics and phytogeography of selected eocene okanagan highlands plants the diverse early to middle eocene okanagan highlands floras of south central british columbia and northeastern washington reflect a time of rapid evolution and the early radiation of many dicot families that are currently significant elements of temperate floras recent studies of the republic washington flora klondike mountain formation and related okanagan floras in british columbia have documented both the earliest and sometimes the only known fossil occurrences of genera today many once more widespread taxa are restricted particularly to asian and or eastern north american refugia examples include members of the families betulaceae birch hazelnut rosaceae rose hamamelidaceae witch hazel and the endemic asian family trochodendraceae earliest occurrences are noted for neviusia rosaceae trochodendron trochodendraceae corylus and carpinus both betulaceae the first unequivocal leaf records of corylopsis and fothergilla both hamamelidaceae and two new eocene species of the extinct fruit palaeocarpinus betulaceae are also recognized today trochodendron and corylopsis are restricted to asia whereas neviusia and fothergilla genera with close asian relatives occur only in north america corylus johnsonii from republic is most similar to the extant asian species c heterophylla c wangii and c ferox neviusia leaves from one mile creek near princeton british columbia are more similar to n cliftonii an endemic from mount shasta california than to n alabamensis of southeastern north america a better documentation of the okanagan highlands floras is essential to our understanding of the evolution of north american temperate floras and the nature of asian north american disjunct taxa

the 1993 killari latur central india earthquake an example of fault reactivation in the precambrian crust the september 30 1993 killari event in central india is a rare incidence of an earthquake occurring within a precambrian craton a pertinent question concerning seismicity in such regions is whether a preexisting fault exists and if so what is its reactivation interval ourstudiesinthe1993rupturezonesuggestthatthekillariearthquakeoccurred in a region of previous seismic activity older thrust sheets and fault gouge presumably formedduringpreviousepisodes wereexposedinadeeptrench thestudiesalsoindicated an obsequent fault line scarp aligned with the current rupture zone the morphological features in the area suggest mass removal of the upper part of the hanging wall on the southwestern side of the rupture existence of a prominent northwest striking structure passing through the epicentral zone is revealed in the digital landsat data these data together with the spatial trend of historic earthquakes along the northwest striking structure reinforce the argument that the earthquake at killari is related to the reactivation of a preexisting fault

geomorphological change detection of an urban meander loop caused by an extreme flood using remote sensing and bathymetry measurements a case study of karoon river iran abstract flooding and flood inundation are key hydrological characteristics of meander loop rivers however the effects of extreme floods on river morphology and spatial patterns of erosion and deposition are poorly understood a detailed geomorphologic change detection and sediment erosion process caused by an extreme flood more than 100 year recurrence interval discharge on 14 apr 2016 was surveyed for a single urban meander loop of the karoon river iran the studied meander loop is located next to the city of the ahavz and has a centerline length of about 14 km the bathymetry in 8892 stable points was measured also the detailed bathymetry layers for before 8 apr 2016 and after 24 apr 2016 the extreme flood event were compared geomorphological change detection gcd results show that in the studied reach about 106 ha of bank erosion was detected with a total volume of approximately 450 600 m3 furthermore total volume of surface lowering and the total volume of surface rising volumes that were obtained were 95421 6 m3 and 98619 0 m3 respectively the talweg length of the studied meander loop decreased about 126 m and the average depth decreased from 3 71 m to 3 14 m after the flood event channel widening as a consequence of the extreme flood was found to be about 21 m 17 the findings of this study indicate that extreme floods play an important role in the sediment budget and morphological evolution of meandering rivers

an evaluation of surface flow types as a rapid measure of channel morphology for the geomorphic component of river condition assessments abstract riverine assessments of channel morphology and fluvial processes typically involve a time consuming survey of channel cross sections and longitudinal profiles expensive aerial imagery and or require specialised knowledge as a result geomorphic input is not widely included in multiparameter river condition assessments we were interested in determining if surface flow type observations can be used as a rapid measure of channel morphology and then subsequently be used in river condition assessments to monitor channel change over time we examined the relationship between flow types e g rippled flow no perceptible flow and channel morphology two aspects of channel morphology were assessed i within reach depth variability and ii cross section geometry e g width area froude number in a two part study each of these was correlated with flow type diversity for a range of study sites from upland and lowland environments in victoria australia we found that an increased diversity of flow types correlated with greater depth diversity based on the coefficient of variation of depth along a reach flow types also correlated well with the cross sectional froude number but less so with other geometric parameters the proportion of flow types present was also notably sensitive to discharge within the low flow range examined 70 99 flow exceedance three geo topes cross section units of a dominant flow type were found to be the most physically distinct units at this cross section scale no perceptible flow deadwater smooth boundary turbulent glide and rippled flow run riffle rippled flow is a revision to previous run riffle classifications and is identified by the presence of unbroken waves of any size with crests moving in a general downstream direction our findings indicate that flow types can provide indicative information on channel morphology along a reach when assessed at low flow levels the diversity of flow types reflects the variability of cross sectional geometry and also the diversity of the channel bed depth on this basis the inclusion of flow type observations in river condition assessments can provide meaningful information on channel morphology in a rapid and repeatable way with repeat surveys flow types could be used as a geomorphic metric to track changes in morphologic diversity over time including changes associated with processes of sediment transport scour and deposition at a reach

early eocene ypresian birds from the okanagan highlands british columbia canada and washington state usa we survey the known avian fossils from ypresian early eocene fossil sites of the north american okanagan highlands mainly in british columbia canada all specimens represent taxa that were pre

application of uav photogrammetry for the multi temporal estimation of surface extent and volumetric excavation in the sa pigada bianca open pit mine sardinia italy in open pit mines monitoring of topographic and volumetric changes through time is found to be of great importance to support excavation stages and to plan rehabilitation strategies in this work we describe a geomatic approach to assess changes in surface mine extent and to quantify excavated volume in the sa pigada open pit mine sardinia italy we performed two drone based photogrammetric surveys in 2013 and 2015 and by means of the structure from motion sfm technique we obtained related 3d dense point clouds and digital orthophotos images were georeferenced thanks to a series of ground control points surveyed with geodetic gps distances between the two clouds were estimated with the recent multiscale model to model cloud comparison m3c2 plug in included in the cloudcompare open source software starting from cloud to cloud distances we calculated the excavated volume of mineral resources between the two surveys results of the m3c2 comparison supported the analysis of the two orthophotos through which accurate limits of the 2013 and 2015 active mine areas rehabilitated area and temporary dumps were identified and drawn in a digital map results obtained in this study suggest that the applied geomatic techniques are suitable for performing accurate change detection analysis in open pit environments and represent a valid support for scientists and technicians allowing to monitor with high spatial and temporal resolutions this approach can be also considered a valid tool to reduce environmental impact from mining

eocene continental climates and latitudinal temperature gradients global climate during the mesozoic and early cenozoic is thought to have been warmer than at present but there is debate about winter temperatures paleontological data indicate mild temperatures even at high latitudes and in mid latitude continental interiors whereas computer simulations of continental paleoclimates produce winter temperatures closer to modern levels foliar physiognomy and floristic composition of 23 eocene floras from the interior of north america and australia indicate cold month means generally 2 c even where the mean annual temperature mat was

relations between postglacial fluvial incision rates and uplift rates in the north island new zealand 1 fluvial incision rates are increasingly being used as a proxy for rock uplift rates for inland settings we test the validity of this approach by comparing incision rates and rock uplift rates along the hikurangi margin new zealand postglacial fluvial incision rates were calculated by measuring the difference in altitude between the last glacial maximum lgm terrace tread 18 2 calendar ka and the present river bed for 10 major rivers catchment areas 1400 5900 km2 incision rates have thus been measured over a half glacial cycle they also represent average rates over the last 18 kyr during which time variations are likely due to processes such as knickpoint retreat rock uplift rates have been estimated from 1 altitude differences between the treads of pairs of fluvial fill terraces 55 and 18 calendar ka assumed to have formed at the same altitude i e rock uplift relative to the geoid 2 present day altitudes of late neogene paleoshoreline marker horizons 1 6 5 7 ma i e rock uplift relative to sea level and 3 present day altitudes of neogene mudstones for which maximum depth of burial has been calculated from porosity i e rock uplift relative to sea level these rock uplift rates overestimate tectonic uplift rates because they do not take into account isostatic compensation due to erosion mean incision rates range up to 11 7 mm yr 1 and mean rock uplift rates range up to 4 1 and 0 9 mm yr 1 for the three methods respectively we have made some qualitative and semiquantitative observations about nontectonic controls on postglacial incision rates and find that localized influence only is exerted by rainfall base level and bedrock lithology while negative or no correlations are shown with lgm fluvial fill thickness and stream power incision rates and uplift rates display a rough correlation with incision rates typically 1 5 5 times uplift rates this relation suggests that tectonic uplift is likely to exert an important control on fluvial incision in the hikurangi margin

paleobotanical evidence of eocene and oligocene paleoaltitudes in midlatitude western north america comparisons of the physiognomy of leaves from modern vegetation of known climates with that of eocene and oligocene fossil leaf assemblages from middle latitudes of western north america indicate paleoaltitudes comparable or higher than those at present using canonical correspondence analysis a multivariate statistical approach that includes nonlinear relationships between characters and environmental parameters we relate leaf physiognomy of fossil samples to modern vegetation of known environmental parameters including moist enthalpy of the atmosphere a thermodynamically conserved quantity of the atmosphere that varies with altitude by estimating enthalpy values for both lowland leaf assemblages and coeval interior leaf assemblages altitudes for the interior assemblages can be estimated to 890 m in northeastern washington and southern british columbia the high eocene altitudes indicate subsidence or collapse of an area undergoing crustal extension and may reflect an immediately preceding period of uplift that triggered the extension similarly other areas that have undergone cenozoic crustal extension appear to have been at least as high as they are at present three sites from the rocky mountains also indicate elevations at least as high as at present and therefore suggest subsidence either resulting from cooling of a hot upper mantle or erosion and isostatic compensation of surrounding terrain high altitudes during eocene and oligocene time in western north america appear to have been normal even in areas such as the green river basin and therefore cast doubt on the commonly inferred late cenozoic uplift of that region

regional and local vegetation community dynamics of the eocene okanagan highlands british columbia washington state from palynology palynofloras from the middle early to early middle eocene okanagan highlands northern washington state and southern british columbia are used to reconstruct vegetation across a broad upland eocene landscape in this preliminary report forest floristic composition is reconstructed using palynological analysis of sediments from republic washington localities of the allenby formation in the princeton region hospital hill one mile creek and summers creek road hat creek mcabee falkland horsefly and driftwood canyon british columbia wind dispersed taxa were dominant in all samples consistent with floras preserved in lacustrine and paludal depositional environments pseudolarix was dominant in five of the floras but abies falkland or ulmus republic corner lot site were dominant in individual samples for some floras betulaceae were dominant for mcabee alnus and allenby formation betula matching megafloral data for these sites some taxa common to most sites suggest cool conditions e g

erosion thresholds and suspended sediment yields waipaoa river basin new zealand characteristics of the suspended sediment load in the waipaoa river new zealand and in two of its tributaries mangatu and te arai rivers are examined for evidence of different dominant erosion processes in the basins upstream different shapes of the suspended sediment concentration water discharge relations lead to differences in long term average yield event yield magnitude frequency relations and relative importance of large flows and rare events in the mangatu river frequent runoff events 2 1 are relatively more important to the long term yield 11 540 t km yr half of the long term average load is transported by events with return periods less than 1 year and there is little evidence of an erosion threshold limitation on sediment supply this is consistent with the predominance in the mangatu basin of hillslope erosion processes that involve scour by surface and channelized runoff particularly gully erosion this contrasts with the te arai river where sediment concentration tends to be much lower at low and moderate flows frequent runoff events transport less of the long term yield 4600 t km 2 yr than do rarer large magnitude flood events event sediment yields are an order of magnitude lower during events with subannual return periods and half of the long term average load is transported during events with a return period of 2 years some of these characteristics appear to result in part from two populations of runoff events in the te arai basin nonetheless they are consistent with field evidence that most of the sediment supplied to the te arai stream network is generated by shallow landslides which are activated once a rainfall threshold is exceeded

fingerprinting suspended sediment sources in the catchment of the river ouse yorkshire uk statistically verified composite fingerprints and a multivariate mixing model have been employed to establish the main sources of the suspended sediment transported through the lower non tidal reaches of the river ouse and one of its main tributaries the river wharfe during the period 1994 1997 in the case of the suspended sediment samples collected from the river ouse the load weighted mean contributions from uncultivated topsoil cultivated topsoil and channel bank sources were estimated to be c 25 38 and 37 respectively while for the river wharfe these sources contributed c 70 4 and 23 respectively c 4 was derived from woodland topsoil suspended sediment samples collected during higher flows evidenced a greater contribution from channel banks than samples collected during lower flows source materials were also differentiated according to the three main geological source areas carboniferous permian and triassic and jurassic and their load weighted mean contributions were estimated to be c 24 41 and 35 for the river ouse and c 91 9 and 0 there are no jurassic rocks in this catchment for the river wharfe respectively when suspended sediment samples from tributary streams were used to characterize each geological source area the equivalent results for the river ouse were c 30 46 and 24 considering the three main tributaries that contribute to the river ouse the load weighted mean contributions from the rivers swale ure and nidd were estimated to be 82 15 and 3 respectively these values have been compared with estimates of the relative magnitude of the annual suspended sediment loads of these three rivers for the years 1995 and 1996 derived from continuous monitoring of discharge and turbidity differences between the two sets of results are ascribed to the different periods of record involved and to the timing of suspended sediment sampling relative to the overall storm hydrograph and thus the degree to which the available samples are representative of the overall suspended sediment flux although a number of limitations must be recognized the fingerprinting approach to source ascription is seen as providing valuable information regarding suspended sediment sources in the study catchments copyright 1999 john wiley sons ltd

mid latitude continental temperatures through the early eocene in western europe branched glycerol dialkyl glycerol tetraethers brgdgts are increasingly used to reconstruct mean annual air temperature maat during the early paleogene however the application of this proxy in coal deposits is limited and brgdgts have only been detected in immature coals i e lignites using samples recovered from schoningen germany 48 n palaeolatitude we provide the first detailed study into the occurrence and distribution of brgdgts through a sequence of early eocene lignites and associated interbeds brgdgts are abundant and present in every sample in comparison to modern studies changes in vegetation type do not appear to significantly impact brgdgt distributions however there are subtle differences between lignites representing peat forming environments and siliciclastic nearshore marine interbed depositional environments using the most recent brgdgt temperature calibration matmr developed for soils we generate the first continental temperature record from central western continental europe through the early eocene lignite derived maat estimates range from 23 to 26 c while those derived from the nearshore marine interbeds exceed 20 c these estimates are consistent with other mid latitude environments and model simulations indicating enhanced mid latitude early eocene warmth in the basal part of the section studied warming is recorded in both the lignites 2 c and nearshore marine interbeds 2 3 c this culminates in a long term temperature maximum likely including the early eocene climatic optimum eeco although this long term warming trend is relatively well established in the marine realm it has rarely been shown in terrestrial settings using a suite of model simulations we show that the magnitude of warming at schoningen is broadly consistent with a doubling of co2 in agreement with late paleocene and early eocene pco2 estimates

effects of hydrological events on morphological evolution of a fluvial system abstract this study quantifies morphological evolution of the dez river iran from 1955 to 2016 the approach uses a sequence of landsat images aerial photos and topographic maps in addition the hydrological data including average daily discharge and yearly maximum discharge at the dezful hydrological station for the period 1955 2016 were used the study reach was divided into 48 meander loops from upstream to downstream active channel width w was determined at 10 m intervals and changes assessed along the study reach of the dez river morphological indices including sinuosity index straight meander length centerline flow length erosion area erodible length channel migration centerline elongation and radius of curvature were calculated in the reach results showed that the study reach of the dez river changed dramatically in response to major floods although the general trend is towards a narrowing of active channel width by 38 in the period 1955 2016 results show that most of the meander loops in the study area extended and expanded between 1989 and 1995 all types of meander change were observed there was a direct correlation between the frequency of hydrological events flood days bigger than 2 years return period and elongation of bends

high resolution topography for understanding earth surface processes opportunities and challenges abstract in the last decade a range of new remote sensing techniques has led to a dramatic increase in terrain information providing new opportunities for a better understanding of earth surface processes based on geomorphic signatures technologies such as airborne and terrestrial lidar light detection and ranging to obtain high resolution topography have opened avenues for the analysis of landslides hillslope and channellization processes river morphology active tectonics volcanic landforms and anthropogenic signatures on topography this review provides an overview of the recent flourishing literature on high resolution topographic analyses underlining their opportunities and critical issues such as their limitations the goal is to provide answers to questions such as what kind of processes can be analyzed through high resolution topographic data and how to do it the review focuses on two different environments natural and engineered landscapes in both contexts high resolution topography offers opportunities to better understand geomorphic processes from topographic signatures particular attention is given to engineered landscapes in which the direct anthropic alteration of processes is significant the last part of the review discusses future challenges

an investigation into the latur earthquake of september 29 1993 in southern india abstract the devastating m w 6 2 latur earthquake of september 29 1993 in south india has claimed an estimated 11 000 human lives with an i max of viii the earthquake was felt to an average distance of 750 km more than 125 shocks were reported to have been felt during august 1992 march 1993 out of these during october november 1992 several shocks of m 2 0 were recorded at the ngri seismic station at hyderabad which is the closest 220 km to the epicentre no such shocks occurred for at least 8 months before the latur earthquake the aftershocks were monitored by a network of up to 21 stations between october 8 1993 and january 31 1994 a majority of the aftershocks occurred within a 10 km radius from the main shock on the basis of the location of aftershocks in the first few days a plane dipping at an angle of 45 towards the southwest and striking at 135 is inferred to be the fault plane which extends to a depth of 4 5 km and on projection meets the surface in the vicinity of the observed surface rupture assuming the aftershock zone to be the rupture zone the stress drop is estimated to be 7 mpa with a maximum displacement of 1 7 m for the main earthquake a unique discovery is the high concentration of helium in the soil in the immediate vicinity of the surface rupture indicating that the rupture extends to the surface from a depth of a few km a detailed broadband magnetotelluric mt investigation revealed the presence of an anomalously high conductive zone at a depth of 6 10 km observation of a pc phase lagging behind the pg phase by about 0 6 to 0 8 s in the seismograms of aftershocks indicating a low velocity zone at 7 to 10 km depth is consistent with the mt results this highly conductive low velocity layer is inferred to be fluid filled the main stress regime in peninsular india is ne compressive stress due to plate tectonic movement erosion of the basalt cover in the deccan plateau may be adding additional compressive stress in the region the existence of a low velocity highly conductive fluid filled layer will enhance stress concentrations in the uppermost brittle part of the crust causing the earthquake

assessment of river bank erosion in southern minnesota rivers post european settlement article i nfo river bank erosion is one of the major sources of sediment for many rivers around the world with the cur rent emphasis on developing total maximum daily loads tmdls for impaired waters in the united states there is heightened interest in quantifying background sediment levels in rivers in this study we assessed variations in river bank erosion over time using a combination of 1855 public land survey system plats aerial photographs from 1938 to 2009 and light detection and ranging lidar data from 2005 to 2009 for sediment impaired rivers in southern minnesota results showed that bank erosion was episodic making comparisons of erosion rates from dissimilar time intervals unreliable for comparable time intervals average river bank retreat rates 0 51 m yr 1 from 1855 to 1938 vs 0 37 m yr 1 from 1938 to 2009 were statistically similar t 2 13 p 0 14 suggesting that bank erosion rates have remained stable since european settlement comparisons over shorter time intervals of 1938 1971 and 1971 2009 also showed similar statistical trends t 0 76 p 0 45 with average river bank retreat rates of 0 57 and 0 50 m yr 1 respectively however additional 145 observations of bank retreat were found in the period 1971 2009 relative to 1938 1971 in dicating that the number of actively eroding river banks may have increased over time contrary to assump tions made in the literature bank erosion measurements using lidar data showed a poor relationship r 2

tertiary climatic changes at middle latitudes of western north america abstract a new multivariate analysis of leaf physiognomy provides the basis for estimating various climatic parameters for angiosperm leaf assemblages estimates from this climate leaf analysis multivariate program clamp are both accurate valid and precise repeatable application of clamp to fossil leaf assemblages from western north america confirms that eocene mean annual temperature mat was generally high early eocene mat 19 c at paleolat 70 n and 27 c at paleolat 45 n significant fluctuations 5 8 in mat occurred during the eocene each successive warm period was cooler than the preceding warm period mean annual range of temperature mart was generally low during the eocene especially at middle latitudes but then markedly increased by 12 13 c at 33 ma as mat decreased by 7 8 c these changes at 33 ma largely involved a decrease in cold month mean temperature which continued to decline into the early miocene but then increased significantly into the mid miocene thermal optimum warm month mean temperature changed little from the eocene through the early miocene this parameter however markedly decreased at 13 ma which coincides with the growth of the east antarctic ice sheet clamp also indicates that the coastal region of western north america had significantly higher mat than interior regions such as the great basin and rocky mountains these differences in mat appeared by or during the eocene and indicate that much of the interior had high altitudes in the paleogene these inferences have a significant bearing on global circulation models proposed for tertiary climates

fault geometry of the mw 7 7 western india intraplate earthquake constrained from double difference tomography and fault plane solutions abstract globally one of the largest intraplate earthquakes of m w 7 7 occurred on 26 january 2001 in the kachchh rift basin krb western india the continuing long aftershock sequence over decades has generated much debate on the seismogenic fault s we have analyzed more than 10 000 aftershocks m w 1 0 recorded by a 50 station broadband network in the region during 2006 2014 a total of 834 aftershocks m w 2 4 each recorded by at least eight broadband seismic stations with a minimum of eight p and six s phases are relocated in this study by double difference tomography tomodd method the relocated aftershocks and velocity images reveal a near vertical or steeply south dipping deeper structure as the source zone of the mainshock and aftershocks the structure correlates well with the geologically mapped south wagad fault swf among the other geologically known faults the kachchh mainland fault kmf and the gedi fault gf are also well identified in the seismic sections further fault plane solutions of 109 aftershocks having m w 3 5 corroborate well with the known faults the geological model and seismological observations suggest that the swf overstepped the kmf and intersects it at depth the intersecting fault zone is the source area for the deeper 10 35 km reverse faulting earthquakes in the krb at the fault end of the swf a heterogeneous velocity structure is imaged which is attributed to a fluid filled rock matrix that triggered the mainshock on the other hand the gf is reported to be a later activated fault to the north of swf it generated some shallower aftershocks 0 20 km mostly by strike slip mechanisms

changes in morphometric meander parameters identified on the karoon river iran using remote sensing data abstract river meander dynamics and mobility are important indicators of environmental change related to climate changes and anthropogenic activities at local and river basin scales the aim of the present study is to identify morphological changes of the karoon river in iran using high accuracy maps and landsat satellite images by analyses during the time period 1989 2008 in this study 20 meandering reaches were analyzed over a 128 km long river reach located in the middle part of the karoon river iran morphometric indicators such as river width w meander neck length l axis length a radius of curvature r water flow length s and sinuosity of meander c were extracted for the identified meanders the results of a paired t test showed that river width w and meander neck length l have significantly changed during the study period 1989 2008 with an increase of 3 5 m for w and a decrease of 274 m for l spearman correlation analysis has shown that meander parameter changes are highly correlated to each other the parameters that do not have significant correlation together are c with w and l w and l and l with s and a during the period of the study the flow length and river sinuosity decreased for the whole river reach by 4 77 km and 0 11 respectively analysis of land use land cover categories 1989 and 2008 using the support vector machine svm and kernel function method served as one of the tools for interpretation of the meander parameter changes these changes can be attributed not only to lu lc riparian vegetation to agriculture area ratio but also to dam construction in the upstream part of the river that leads to major hydrological regime and sediment transfer alteration sediment extraction may also be an important factor

slope control on the frequency distribution of shallow landslides and associated soil properties north island new zealand the extrapolation of results from field trials to larger areas of land for purposes of regional impact assessment is an important issue in geomorphology particularly for landform properties that show high stochastic variability in space and time such as shallow landslide erosion it is shown in this study that by identifying the main driver for spatial variability in shallow landslide erosion at field scales namely slope angle it is possible to develop a set of generic functions for assessing the impact of landslides on selected soil properties at larger spatial scales and over longer time periods research was conducted within an area of pastoral soft rock tertiary hill country in the north island of new zealand that is subject to infrequent high intensity rainfall events producing numerous landslides most of which are smaller than several hundred square metres in size and remove soil to shallow depths all landslides were mapped within a 0 6 km2 area and registered to a high resolution 2 m slope map to show that few landslides occur on slopes 24 the areal density of landslides from all historical events showed an approximately linear increase with slope above 24 integrating landslide densities with soil recovery data demonstrates that the average value of a soil property fluctuates in a saw tooth fashion through time with the overall shape of the curve controlled by the frequency of landslide inducing storm events and recovery rate of the soil property between events despite such fluctuations there are gradual declines of 7 5 in average total carbon content of topsoil and 9 5 in average soil depth to bedrock since the time of forest clearance results have application to large scale sediment budget and water quality models and to the new zealand soil carbon monitoring system cms copyright 2012 john wiley sons ltd

holocene coastal evolution and uplift mechanisms of the northeastern raukumara peninsula north island new zealand abstract the coastal geomorphology of the northeastern raukumara peninsula new zealand is examined with the aim of determining the mechanisms of holocene coastal uplift elevation and coverbed stratigraphic data from previously interpreted coseismic marine terraces at horoera and waipapa indicate that despite the surface morphology there is no evidence that these terraces are of marine or coseismic origin early holocene transgressive marine deposits at hicks bay indicate significant differences between the thickness of preserved intertidal infill sediments and the amount of space created by eustatic sea level rise therefore uplift did occur during early holocene evolution of the estuary the palaeoecology and stratigraphy of the sequence shows no evidence of sudden land elevation changes beach ridge sequences at te araroa slope gradually toward the present day coast with no evidence of coseismic steps the evolution of the beach ridges was probably controlled by sediment supply in the context of a background continuous uplift rate no individual dataset uniquely resolves the uplift mechanism however from the integration of all evidence we conclude that holocene coastal uplift of this region has been driven by a gradual aseismic mechanism an important implication of this is that tectonic uplift mechanisms do vary along the east coast of the north island this contrasts with conclusions of previous studies which have inferred holocene coastal uplift along the length of the margin was achieved by coseismic events this is the first global example of aseismic processes accommodating uplift at rates of 1 mm yr 1 adjacent to a subduction zone and it provides a valuable comparison to subduction zones dominated by great earthquakes

eocene paleontology and geology of western north america western north america preserves a rich record of eocene life and environments under globally warm climates and represents an interval where significant coal and other minerals were deposited the eocene is of interest to biologists and paleontologists for its record of the appearance and rise to dominance of many plant insect and mammal groups now typical of the temperate forests of north america admixed with groups now well represented in tropical areas or restricted to eastern asia this record is also of interest for its potential contribution to our understanding of interactions between climate the biota and the ecosystems they occupied under atmospheric carbon dioxide levels much higher than today documentation of the eocene in western north america offers insights into the effects of future greenhouse climates a special symposium held at the 2014 annual meeting of the geological society of america in vancouver british columbia brought together geologists paleontologists and biologists w

last glacial aggradation and postglacial sediment production from the non glacial waipaoa and waimata catchments hikurangi margin north island new zealand abstract the sediment flux generated by postglacial channel incision has been calculated for the 2150 km 2 non glacial waipaoa catchment located on the tectonically active hikurangi margin eastern north island new zealand sediment production both at a sub catchment scale and for the waipaoa catchment as a whole was calculated by first using the tensioned spline method within arc map to create an approximation of the aggradational waipaoa 1 surface contemporaneous with the last glacial maximum and second using grid calculator functions in the gis to subtract the modern day surface from the waipaoa 1 surface the waipaoa 1 surface was mapped using stereo aerial photography and global positioning technology fixed the position of individual terrace remnants in the landscape the recent discovery of kawakawa tephra within waipaoa 1 aggradation gravels in this catchment demonstrates that aggradation was coincidental with or began before the deposition of this 22 600 14 c year old tephra and using the stratigraphic relationship of rerewhakaaitu tephra the end of aggradation is dated at ca 15 000 14 c years ca 18 000 cal years bp the construction of the waipaoa 1 terrace is considered to be synchronous and broadly correlated with aggradation elsewhere in the north island and northern south island indicating that aggradation ended at the same time over a wide area subsequent downcutting a manifestation of base level lowering following a switch to postglacial incision at the end of glacial age aggradation points to a significant southern hemisphere climatic warming occurring soon after ca 15 000 14 c years ca 18 000 cal years bp during the older dryas interval elevation differences between the waipaoa 1 c 15 ka terrace and the level of maximum channel incision i e before aggradation since the turn of the 20th century suggest about 50 of the topographic relief within headwater reaches of the waipaoa catchment has been formed in postglacial times the postglacial sediment flux generated by channel incision from waipaoa catchment is of the order of 9 5 km 3 of which 6 6 km 3 is stored within the confines of the poverty bay floodplain thus although the postglacial period represented a time of high terrigenous sediment generation and delivery only 30 of the sediment generated by channel incision from waipaoa catchment probably reached the marine shelf and slope of the hikurangi margin during this time the smaller adjacent waimata catchment probably contributed an additional 2 6 km 3 to the same depocentre to give a total postglacial sediment contribution to the shelf and beyond of 5 5 km 3 sediment generated by postglacial channel incision represents only 25 of the total sediment yield from this landscape with 75 of the estimated volume of the postglacial storage offshore probably derived from hillslope erosion processes following base level fall at times when sediment yield from these catchments exceeded storage

accuracy assessment of georectified aerial photographs implications for measuring lateral channel movement in a gis aerial photographs are commonly used to measure planform river channel change we investigated the sources and implications of georectification error in the measurement of lateral channel movement by testing how the number 6 30 and type human versus natural landscape features of ground control points gcps and the order of the transformation polynomial first second and third order affected the spatial accuracy of a typical georectified aerial photograph error was assessed using the root mean square error rmse of the gcps as well as error in 31 independent test points the rmse and the mean and median values of test point errors were relatively insensitive to the number of gcps above eight but the upper range of test point errors showed marked improvement i e the number of extreme errors was reduced as more gcps were used for georectification using more gcps thus improved overall georectification accuracy but this improvement was not indicated by the rmse suggesting that independent test points located in key areas of interest should be used in addition to rsme to evaluate georectification error the order of the transformation polynomial also influenced test point accuracy the second order polynomial function yielded the best result for the terrain of the study area gcp type exerted a less consistent influence on test point accuracy suggesting that although hard edged points e g roof corners are favored as gcps some soft edged points e g trees may be used without adding significant error based upon these results we believe that aerial photos of a floodplain landscape similar to that of our study can be consistently georectified to an accuracy of approximately f5 m with 10 chance of greater error the implications of georectification error for measuring lateral channel movement are demonstrated with a multiple buffer analysis which documents the inverse relationship between the size of the buffers applied to two channel centerlines and the magnitude of change detected between them this study demonstrates the importance of using an independent test point analysis in addition to the rsme to evaluate and treat locational error in channel change studies d 2005 published by elsevier b v

volumetric measurement of river bank erosion from sequential historical aerial photography abstract understanding of the relative contribution of bank erosion to sediment budgets in new zealand is limited few measurements of bank erosion rates exist and this is a major limitation to the development of a locally calibrated model of bank erosion the new zealand sediment budget model sednetnz predicts bank erosion based on preliminary data and this study aims to underpin the development of an improved model for bank erosion photogrammetric techniques and lidar were used to collect data on bank erosion rates for five different river reaches ranging from 3 to 14 km in length in the kaipara catchment northland new zealand changing river channel planform between the 1950s and 2015 was assessed using four to five well spaced dates of historical aerial photographs changes in planform were combined with bank height to calculate erosion and accretion volumes which were compared with sednetnz modelled estimates erosion and accretion is relatively evenly balanced in the study sites the largest difference in terms of relative proportions of erosion and accretion are found along the tangowahine river 13 4 km reach length where 492 000 m3 of sediment eroded between 1956 and 2015 compared to 364 000 m3 of accretion lateral migration rates erosion for the five river reaches range between 0 14 m yr 1 and 0 21 m yr 1 and are comparable with those measured by previous assessments in new zealand the migration rates in channel widths per year for the three larger rivers stream order 5 6 range between 0 4 and 0 8 of channel width per year in contrast the smaller streams stream order 3 4 are retreating more rapidly with width averaged rates of 1 7 and 3 0 current sednetnz modelling tends to underestimate the bank height and greatly overestimates the migration rate

geomorphic impacts of a 100 year flood kiwitea stream manawatu catchment new zealand abstract the geomorphic impacts of a 100 year flood are assessed in the kiwitea stream 254 km 2 a tributary within the manawatu river catchment new zealand using sequential aerial photographs and reach based morphological sediment budgeting channel expansion and avulsion eroded in excess of one million cubic metres of sediment over 1 km 2 of floodplain along a 30 km long reach of kiwitea stream channel transformation was spatially discontinuous and predominantly associated with large scale bank erosion in response to a flood over 5 times bigger than the mean annual flood annual recurrence interval ari 100 years total energy expenditure of this flood in the kiwitea was 14 900 10 3 j the spatial discontinuity of channel transformation relates to valley floor and channel configurations high stream powers generated in confined channels at bends produced catastrophic channel transformation where flood flows dissipated overbank stream powers and the extent of channel transformation were reduced hydrologic hydraulic and geomorphic variables can be invoked to thus explain the variability of geomorphic impacts encountered during this event

the 1993 killari earthquake in central india a new fault in mesozoic basalt flows the mw 6 1 1993 killari earthquake in central india was one of the deadliest earthquakes to occur in a stable continental area it had a centroid 2 6 km deep and ruptured to the surface a good fit of teleseismic waveforms is obtained with a simple 4 2 s long pulse that releases a moment mo 1 8 1018 nm from a reverse fault rupture with strike dip and rake of 126 46 and 100 respectively a 10 km wide meizoseismal area is tightly defined by relative casualty count in the center of this area aftershock hypocenters baumbach et al 1994 outline a southwest dipping rupture that extends 5 5 8 km along strike and from the surface 8 10 km along dip these dimensions correspond with an average displacement of 1 5 0 8 m and a stress drop of 10 4 5 mpa respectively we mapped a 1 km long zone of compressional scarps which are spatially correlated with the rupture outlined by hypocenter in the central portion of this zone the scarps are multiple and face in opposite directions deformation features indicate north northeast directed shortening of at least 0 5 m a leveling profile of an irrigation canal about 3 km northwest of the scarps displays a one wavelength warp about 1 km long and 1 3 m in peak to peak amplitude that may reflect deformation associated with the rupture two trenches across the scarps exposed faults that offset the soil rock interface as much as 50 cm we found no convincing evidence suggesting that these faults existed prior to the earthquake in the basalt these faults reactivated exfoliation fractures in shear but were not associated with a zone of preexisting breccia and mineralization the hypothesis that the 1993 rupture is a new fault in the deccan traps is consistent with lack of geomorphic evidence of prior faulting and with the lack of accumulated deformation or tilting in basalt layers exposed as close as few tens of meters from the scarp no convincing clues about a seismogenic fault have yet been detected from either historic seismicity or geology in the 1993 source area but a burst of seismicity 1 year before the mainshock and 2 5 years after the first impounding of a nearby reservoir was interpreted by some as a possible precursor to a larger earthquake before the 1993 mainshock precursory seismicity and artificial effects that cause significant mechanical changes in the crust may provide an indication of future potentially damaging earthquakes in stable continental areas

correlation of fluvial terraces within the hikurangi margin new zealand implications for climate and baselevel controls abstract a correlation of fluvial terraces is presented for eight non glacial catchments of the eastern north island new zealand within the actively uplifting hikurangi margin using a combination of loess and tephra coverbed stratigraphy and radiocarbon and osl dating of fluvial deposits and loess coverbeds we demonstrate correlation of four fill terraces t1 t4 the available age constraints suggest t1 15 30 ka t2 31 50 ka t3 50 70 ka and t4 115 ka but the association and temporal link with loess deposits suggest correlation with cold periods and thus the refinement of t2 late mis 3 31 40 ka t3 mis 4 55 70 ka t4 mi substage 5b 90 ka 5d 110 ka or mis 6 140 160 ka the ability to correlate terraces between catchments plus the lack of independent evidence for tectonic triggering events indicates terraces have probably formed in response to either climate terrestrial or baselevel sea level control climate control is indicated by the temporal link of post glacial incision with re establishment of forest cover and of lgm aggradation with limited grass and shrub cover and periglacial processes aggradation due to increased sediment supply under reduced vegetation is dramatically demonstrated by formation of the taupo pumice alluvium terrace in response to inundation by volcanic deposits unwelded ignimbrite following the 1 8 ka taupo eruption and the response to post settlement

the 2001 bhuj earthquake tomographic evidence for fluids at the hypocenter and its implications for rupture nucleation 1 the january 26 2001 bhuj earthquake mw 7 6 is one of the most catastrophic indian earthquakes we have investigated the 3 d seismic velocity and poisson s ratio structures of the bhuj source area to understand the probable cause of triggering the earthquake we used 1948 p and 1865 s wave high quality arrival times from 331 aftershocks recorded at a temporary seismic network significant variations up to 5 in velocity and 10 in poisson s ratio are revealed in the aftershock area the mainshock is located in a distinctive zone characterized by high vp low vs and high poisson s ratio in the depth range of 20 to 30 km and extending 15 to 30 km laterally this feature is very similar to that of the 1995 kobe earthquake zhao et al 1996 the anomaly may be due to a fluid filled fractured rock matrix which might have contributed to the initiation of the bhuj earthquake

development of a new zealand sednet model for assessment of catchment wide soil conservation works abstract much hill country in new zealand has been converted from indigenous forest to pastoral agriculture resulting in increased soil erosion following a severe storm that hit the manawatu wanaganui region in 2004 and caused 62 000 landslides the horizons regional council have implemented the sustainable land use initiative slui a programme of widespread soil conservation we have developed a new zealand version sednetnz of the australian sednet model to evaluate the impact of the slui programme in the 5850 km2 manawatu catchment sednetnz spatially distributes budgets of fine sediment in the landscape it incorporates landslide gully earthflow erosion surficial erosion bank erosion and flood plain deposition the important forms of soil erosion in new zealand modelled suspended sediment loads compared well with measured suspended sediment loads with an r2 value of 0 85 after log transformation a sensitivity analysis gave the uncertainty of estimated suspended sediment loads to be approximately plus or minus 50 at the 95 confidence level it is expected that by 2040 suspended sediment loads in targeted water management zones will decrease by about 40 the expected decrease for the whole catchment is 34 the expected reduction is due to maturity of tree planting on land at risk to soil erosion the 34 reduction represents an annual rate of return of 20 on 20 million nz of investment on soil conservation works through avoided damage to property and infrastructure and avoided clean up costs

erosion process contribution to sediment yield before and after the establishment of exotic forest waipaoa catchment new zealand abstract the east coast region of the north island new zealand is well known for its severe erosion high sediment yields flooding and sedimentation following extensive deforestation of its indigenous forest during the late 19th and early 20th centuries for six decades thereafter extensive grazing cattle and sheep left a legacy of highly degraded hill country much of which has since been retired and planted in exotic forest primarily to control erosion previous studies have documented the extent of gully erosion calculated erosion rates and sediment delivery from gullies to the channel load within the study basin but this has not been quantified for the more extensive mass movement processes including slump earthflow and shallow landslides additionally the magnitude of the effect of reforestation on sediment load at subcatchment level and ultimately on sediment yield at catchment scale for this combination of erosion processes and over the time frame of a rotation of exotic forest 28 years is unknown for a 140 km 2 study basin located in the headwaters of the 2150 km 2 waipaoa river catchment we establish the contribution to basin sediment load by each of these erosion processes spanning a 50 year period that includes a 28 year reforestation effort we quantified the effectiveness of exotic reforestation as an erosion control strategy by using the mapped extent of each of the erosion processes before planting i e 1939 59 as the benchmark against which any subsequent change in eroded area km 2 was measured based on this process based erosion load was calculated for the pre planting period 1939 59 for the period 10 years after planting commenced 1960 69 and again for the period 1970 88 which marked the completion of planting within the study basin the study basin sediment load is then expressed as a proportion percentage of the measured sediment yield mt y 1 of the wider waipaoa river catchment the net area affected by erosion and erosion rates within the study basin peaked at 10 all processes combined and 28000 4000 t km 2 y 1 respectively during the early planting period 45 of study basin planted at this time gullies contributed 59 of the total sediment load at a rate of 2 3 0 3 mt y 1 slumps 34 1 3 0 2 mt y 1 shallow riparian landslides 6 0 2 0 03 mt y 1 and earthflows 1 0 05 0 08 mt y 1 although reforestation proved effective in stabilising shallow landslides and earthflows the resultant reduction in their contribution to basin sediment load and to overall catchment yield was minimal the greatest reduction in sediment load occurred during the latter part of the reforestation period 1970 88 as the numerous small to medium sized gullies stabilised coincident with canopy closure 8 10 years after planting however the larger gully mass movement complexes failed to stabilise in response to reforestation and they remained the dominant source of sediment contributing an order of magnitude more than slumps and two orders of magnitude more than shallow landslides and earthflows basin scale erosion and denudation rates all processes combined but dominated by gullies for the pre reforestation period averaged 22 000 3000 t km 2 y 1 11 mm y 1 peaked during the early reforestation period at 28 000 4000 t km 2 y 1 14 mm y 1 then decreased to 13 500 2000 t km 2 y 1 7 mm y 1 in response to reforestation and averaged 20 000 3000 t km 2 y 1 10 mm y 1 for the duration of the study period significantly the anthropogenic influence following european settlement of the study basin produced degradation rates an order of magnitude greater than the 1 mm y 1 estimated for the 17 6 cal ka bp post last glacial maximum period retirement of the most severely eroding hill country and subsequent establishment of an exotic forest covering 6 of the waipaoa catchment area effected an overall 62 reduction in the erosion affected area and a 51 reduction in the denudation and erosion rates potentially equivalent to an estimated 12 reduction in sediment yield of the waipaoa river we conclude that a greater or similar level of success could be achieved within three decades of forest establishment elsewhere in the east coast region by specifically targeting gully mass movement complexes particularly in high sediment yielding river systems such as the waiapu catchment

earthquake locations and three dimensional crustal structure in the coyote lake area central california previous work on the simultaneous inversion method has been improved and extended to incorporate iterative solution for earthquake locations and laterally heterogeneous structure approximate ray tracing and parameter separation are important elements of the improved method application of the method to p wave arrival time data recorded by stations of the u s geological survey central california network yields a three dimensional model for the velocity structure of the upper crust in an area encompassing the rupture zone of the coyote lake earthquake of august 1979 very strong correlations between the velocity model and the geology and gravity and magnetic anomalies are observed improved estimates of the locations of earthquakes in the study area are also determined the relocation of explosions indicates epicentral accuracies of the order of a kilometer or better based on the revised hypocentral locations it is concluded that the san andreas fault is vertical in this area with no actual offset between the epicenters and the fault trace in contrast the calaveras has two or more active fault surfaces one nearly vertical and another dipping 75 to the northeast

seismic tomography structure of the 1993 killari earthquake source area the aftershock sequence of the 30 september 1993 killari earthquake in central india recorded by 14 temporary seismograph stations was used for seismic tomography study of the source area about 1500 p and 1200 s phases were inverted by the local earthquake tomography method the tomography structures revealed in this study shed new light in understanding seismotectonics of the killari earthquake sequence the contact of the low velocity and high velocity zones has been the source area for the mainshock manuscript received 24 july 2001

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

gully erosion and sediment production te weraroa stream new zealand conversion to pasture early in the twentieth century was ameliorated by reforestation that commenced in 1962 estimates of sediment production were made using the change in gully area observed in sequential aerial photographs channel storage was assessed from stream cross section surveys at its peak gully erosion affected 6 of the total catchment area the amount of sediment contributed from gullies declined by 62 as the forest became established but of the 28 7 mt of sediment generated by gully erosion between 1950 and 1988 48 was stored in the channel along the lower 8 km of te weraroa stream even if the amount of sediment generated by gully erosion continues to decline it likely will be many decades before the gravel is released from storage index terms 1815 hydrology erosion and sedimentation 1824 hydrology geomorphology 1625 1878 hydrology water energy interactions keywords channel storage gully erosion sediment production citation gomez b k banbury m marden n a trustrum d h peacock and p j hoskin gully erosion and sediment production te weraroa stream new zealand water resour res 39 7 1187 doi 10 1029 2002wr001342 2003