late miocene environmental change in nepal and the northern indian subcontinent stable isotopic evidence from paleosols neogene sediments belonging to the siwalik group crop out in the himalayan foothills along the length of southern nepal carbon and oxygen isotopic analyses of siwalik paleosols from four long siwalik sections record major ecological changes over the past 11 m y the carbon isotopic composition of both soil carbonate and organic matter shifts dramatically starting ca 7 0 ma marking the displacement of largely c3 vegetation probably semi deciduous forest by c4 grasslands by the beginning of the pliocene all the flood plains of major rivers in this region were dominated by monsoonal grasslands the floral shift away from woody plants is also reflected by the decline and final disappearance of fossil leaves and the decrease in coal logs in the latest miocene a similar carbon isotopic shift has been documented in the paleosol and fossil tooth record of pakistan and in terrigenous organic matter from the bengal fan showing that the floral shift was probably continentwide the latest miocene also witnessed an average change of 4 in the oxygen isotopic composition of soil carbonate as observed previously in pakistan the reasons for this are unclear if not diagenetic a major environmental change is indicated perhaps related to that driving the carbon isotopic shift recently described pollen and leaf fossils from the surai khola section show that evergreen forest was gradually displaced by semi deciduous and dry deciduous forest between 11 and 6 ma the gradual nature of this floral shift which culminated in the rapid expansion of c4 grasses starting 7 0 m y ago is difficult to explain by a decrease in atmospheric pco2 alone cerling et al 1993 but fits well with a gradual onset of monsoonal conditions in the late miocene in the northern indian subcontinent himalayan uplift driving both monsoonal intensification and consumption of co2 through weathering may be the common cause behind major late miocene environmental change globally however the decline of effective moisture associated with monsoon development has probably slowed not increased the rate of consumption of co2 by chemical weathering of himalayan sediments

provenance of post wapiabi sandstones and its implications for campanian to paleocene tectonic history of the southern canadian cordillera late campanian to early paleocene sandstones of the alberta foothills were derived from three types of rocks i andesitic dacitic volcanic rocks that were presumably comagmatic with middle to late mesozoic plutons in the omineca crystalline belt ii low grade metamorphic rocks in the suprastructure of the omineca crystalline belt and iii sedimentary rocks in die rocky mountain thrust belt principally pelitic rocks in the western main ranges and carbonates and chert arenites in the eastern main and front ranges a paucity of quartzo feldspathic rocks fragments and potassium feldspar indicates that the core of the omineca crystalline belt was not extensively exposed at that time vertical trends in composition of the sandstones reveal five petrographic stages stage i is dominated by volcanic rock fragments and plagioclase suggesting that initial progradation of the sediment was largely a response to coeval volcanism or tectonic emplacement of older volcanic rocks stages iii and v are characterized

the stable isotopic composition of modern soil carbonate and its relationship to climate the oxygen isotopic composition of modern soil carbonate is well correlated with the isotopic composition of local meteoric water the carbon isotopic cycle for co 2 in soils can be described in terms of the proportion of biomass using the c 4 photosynthetic pathway and the co 2 respiration rate of the soil at low soil respiration rates significant atmospheric co 2 mixing can occur in general the carbon isotopic composition of soil carbonate is related to the proportion of c 4 biomass present in soil but soils that freeze to the depth of carbonate formation often have a significant atmospheric component this suggests that freezing of the soil solution should be considered as another important mechanism for soil carbonate formation because of these relationships the isotopic composition of soil carbonate may be a paleoclimatic and paleoecologic indicator in cases in which diagenetic alteration has not occurred

controls on the spatial and temporal variability of 222rn in riparian groundwater in a lowland chalk catchment radon is a powerful tracer of stream aquifer interactions however it is important to consider the source and behaviour of radon in groundwater when interpreting observations of river radon in relation to groundwater discharge here we characterise the variability in groundwater radon concentrations in the riparian zone of a chalk catchment groundwater 222rn radon concentrations were determined in riparian zone boreholes at two sites in the lambourn catchment berkshire uk over a two year period in addition borehole core material was analysed for 226ra radium and to determine radon emanation radon and radium concentrations and radon emanation were found to change with depth and temporal variations in groundwater radon concentrations were found at different scales the abundance of radium and emanation of radon increased nearer the surface leading to greater groundwater radon concentrations it is shown that seasonal changes in water table elevation can to lead to variable radon concentrations in groundwater as zones of radon production become hydraulically active groundwater radon concentrations in shallow piezometers were found to respond to both seasonal changes in the water table and individual rainfall events riparian sources of radon can be variable and are therefore potentially influential in the radon signals observed in rivers and should be properly characterised when interpreting river radon inputs

piggyback basin in the sevier orogenic belt utah implications for development of the thrust wedge timing data on a frontal thrust system indicate that the sevier thrust wedge of central utah advanced rapidly to its ultimate structural front in 30 m y between early albian and campanian time it then persisted by out of sequence thrusting for an additional 25 m y until the early eocene the key to the history of the frontal thrust is a piggyback basin that formed on the hanging wall unconformity bounded sedimentary units within the basin thin both westward and eastward onto structures generated by thrust faulting up to 860 m of upper campanian to lower eocene strata accumulated between these structures which consist of a ramp anticline in the west and a thrust duplex in the east the newly recognized interaction of coeval deposition and thrust deformation permits revised limits on the inception and longevity of the frontal thrust system

paleoatmospheric pco2 fluctuations across the cretaceous tertiary boundary recorded from paleosol carbonates in ne china abstract a dramatic change in atmospheric composition has been postulated because of global carbon cycle disruption during the cretaceous k tertiary t transition following the chicxulub impact and deccan trap eruptions here pedogenic carbonates were collected from drill core of a borehole sk 1 n straddling the late cretaceous and early paleocene strata in the songliao basin northeast china to reconstruct atmospheric co 2 concentrations using a paleosol paleobarometer our estimates for atmospheric pco 2 from paleosol carbonates range between 277 115 ppmv and 837 164 ppmv between 67 8 ma and 63 1 ma one large 66 65 5 ma and several small co 2 spikes 64 7 64 2 ma during the latest maastrichtian to earliest danian are reported here and incorporated with previously published pco 2 estimates also estimated from paleosol carbonates these co 2 spikes are attributed to one million year long emplacement of the large deccan flood basalts along with the extraterrestrial impact at the k t boundary

systematics of the equatorward diffuse auroral boundary dmsp f2 and dmsp f4 precipitating electron data are used to determine statistically the systematic variations of the equatorward diffuse auroral boundary with kp as a function of local time this work extends a previous study of dawn and dusk boundaries to the noon and midnight regions the boundaries are well ordered by kp in the night sector but show increasingly greater scatter from dawn to postnoon in the noon sector it is often the case that no diffuse aurora is discernible within detector sensitivity the equatorward diffuse auroral boundary is well fit by a circle at each activity level the center of the circle is offset from the geomagnetic pole and the radius of the circle increases with increasing magnetic activity the circular fits are projected to the ecliptic plane by using the mead fairfield magnetic field model where they are identified with the inner edge of the plasma sheet in order to make comparison with volland stern type convection electric field predictions previously found variations of the electric field with kp are confirmed including a rotation of the axis of symmetry away from the dawn dusk meridian all equatorward auroral boundaries from dmsp for 1978 were compiled using the equations for boundary variations with kp each evening sector boundary was projected to a midnight boundary the projected midnight boundary serves as an index of auroral activity and an indicator of the strength of the large scale magnetospheric convection electric field the auroral boundary index is given in monthly plots for 1978

direct observations of the evolution of polar cap ionization patches patches of ionization are common in the polar ionosphere where their motion and associated density gradients give variable disturbances to high frequency hf radio communications over the horizon radar location errors and disruption and errors to satellite navigation and communication their formation and evolution are poorly understood particularly under disturbed space weather conditions we report direct observations of the full evolution of patches during a geomagnetic storm including formation polar cap entry transpolar evolution polar cap exit and sunward return flow our observations show that modulation of nightside reconnection in the substorm cycle of the magnetosphere helps form the gaps between patches where steady convection would give a tongue of ionization toi

understanding parafluvial exchange and degassing to better quantify groundwater inflows using 222rn the king river southeast australia 222rn is an important tracer for quantifying groundwater inflows to rivers especially where groundwater and surface water have similar major ion and stable isotope geochemistry uncertainties in the 222rn mass balance arise however from not accurately estimating the degree of degassing of 222rn to the atmosphere and the extent to which interaction within the parafluvial zone provides an additional source of 222rn this study estimates both 222rn production in the parafluvial zone and degassing along a 75km stretch of the king river australia in order to more precisely quantify groundwater inflows the contribution of 222rn from the parafluvial zone fp was estimated using 222rn emanation rates from near river sediments and assessment of the residence time of water in the parafluvial zone from 222rn activities and cl concentrations in water the alluvial sediments values of fp range from 40 400bq m day in the upper king to 8500bq m day in the lower king corresponding to differences in the mineralogy and the volume of the parafluvial zone the gas transfer coefficient k was estimated by matching groundwater inflows to observed increases in river discharge during a period of low discharge k decreases from 25day 1 in the upper king to 3day 1 in the lower king these k values are higher than those from most empirical formulations probably due to the extensive pool and riffle sections that promote degassing the king river is gaining in its upper and middle sections but several of the lower reaches are losing groundwater inflows on a reach scale are as high as 10m3 m day and cumulative inflows along the 75km stretch are up to 19 000m3 day groundwater inflows increase proportional to total flow reflecting the response of both groundwater and surface water systems to rainfall uncertainties in the calculated groundwater inflows are reduced by independently estimating k from the discharge data however calculated inflows are up to 40 higher if parafluvial flow were not taken into account predicted rn activities from emanation measurements agree with those measured in groundwater contribution of rn from parafluvial zone is assessed rn degassing is independently assessed by comparison with flow gauge data rn degassing is higher than predicted from empirical formulations due to pool and riffle sections king river transitions from gaining in upper sections to losing in lower sections

sedimentation in a tectonically partitioned nonmarine foreland basin the lower cretaceous kootenai formation southwestern montana the lower cretaceous kootenai formation in southwestern montana was deposited in the nonmarine cordilleran foreland basin in the united states during a period of intensified uplift in the westward adjacent but increasingly impingent sevier fold thrust belt concurrently the foreland basin was partitioned by uplift of intra foreland structural elements and incipient plutonism kootenai fluvial and fluviolacustrine depositional systems developed and evolved in response to changing basin architecture the kootenai thus provides a case study of nonmarine sedimentary responses to tectonic partitioning in a foreland basin the following criteria for recognition of tectonic partitioning of a nonmarine foreland basin are demonstrated by the kootenai 1 complex internalized drainage patterns which locally diverge from the over all regional paleoslope direction and a typical longitudinal pattern 2 intraformational and interformational unconformities both proximal to the fold thrust belt and within the foreland basin 3 evidence for cannibalization and redistribution of foreland basin sediments 4 abrupt deflections of paleodrainage axes in response to initiation of intraforeland uplifts and 5 dramatic base level alterations and consequent changes of fluvial geomorphology as a result of tectonic partitioning and segmentation of the foreland basin kootenai sedimentation can be divided into six phases 1 a tectonic pulse in the sevier fold thrust belt produced a thin but widespread sheet of gravel alluvium referred to as the basal conglomerate member which was deposited by a shallow perhaps ephemeral gravel bed braided stream system drainage was predominantly eastward across the axis of the foreland basin 2 subsequently initial activation of intra foreland structures over the present tobacco root madison gravelly and beartooth archean blocks and the boulder batholith caused reworking of the basal conglomerate in all but the westernmost foreland basin although the topographic manifestations of these uplifts were subtle the foreland basin was effectively partitioned into at least four distinct drainage basins the resulting deposit commonly called the pryor member but here referred to as the first sandstone member was deposited by sand and gravel dominant braided stream systems in the west and east respectively paleodrainage directions in the western foreland basin were southward but over all drainage was northward 3 a period of mud dominant sedimentation followed deposition of the first sandstone probably resulting from a combination of decreased tectonism influx of siliceous volcanic ash and change in source lithology 4 renewed tectonic activity in the fold thrust belt generated a second episode of coarse grained alluvial sedimentation producing the kootenai second sandstone member basin partitioning was accentuated but drainage directions remained essentially unchanged initial activation of the blacktail snowcrest uplift dammed the southern portion of the second sandstone fluvial system base level was elevated and a major anastomosed stream system developed upstream from the structural dam downstream from the axis of the uplift a transport efficient probably entrenched meandering system developed 5 the remainder of kootenai siliciclastic deposition was dominated by muddy fluvial and fluviolacustrine systems the foreland basin configuration remained essentially unchanged as drainage became ponded in response to further elevation of base level as basin partitioning continued an extensive carbonate lacustrine interval punctuated this period of sedimentation 6 gradual southward transgression of the cretaceous sea left a transitional fluviolacustrine to marine imprint on the sedimentary record of the uppermost kootenai and overlying blackleaf formation rejuvenation of orogenesis in the fold thrust belt augmented by cratonic and major intraforeland volcanic and sedimentary lithic sources renewed the supply of coarse grained detritus to the foreland basin during deposition of the blackleaf

the implications of laboratory222rn flux measurements to the radioactivity in groundwaters the case of a karstic limestone aquifer laboratory time scale experiments were conducted on carboniferous limestone gravels from the mendip hills area england with the purpose of evaluating the release of 222 rn to the water phase the specific surface areas of the samples were 4 14 and 1 69 cm 2 g 1 which provided respectively values of 50 6 and 12 7 pci for the released rn these results allowed the calculation of the emanation coefficient of this rock matrix with respect to the release of rn where completely different values corresponding to 23 and 6 were found suggesting that the extent to which grain boundaries or imperfections in aggregates of micro crystals of calcite intersect the particle surface certainly affects the rn release they also permitted the evaluation of models for the generation of rn in rocks and transfer to water in order to interpret the radioactivity due to this gas in groundwaters from the karstic aquifer of the mendip hills area where the calculated activities in groundwater based on the values of 23 and 6 for the emanation coefficient were about 51 and 15 times higher than actually measured in groundwater therefore the emanation coefficient in nature is considerably smaller than in the lab experiment and another factor k 0 k 1 may be introduced into the equations related to the modelling with the aim of adjusting the theoretical practical results

equable climates during earth history eocene and cretaceous climate model experiments demonstrate that regardless of conditions of warm polar oceans differences in pole to equator surface temperature gradient or topography above freezing surface temperatures in winter for continental interiors at middle to high latitudes cannot be maintained continental interiors will have cold winter temperatures even during globally warm periods unless currently unrecognized forcing factors influenced past climates if model simulations of eocene and cretaceous climates are accurate the term equable as it applies to paleoclimate should be reconsidered

depth to pedogenic carbonate horizon as a paleoprecipitation indicator an analysis of 1168 modern soil profiles from the u s natural resources conservation service yields no correlation between mean annual precipitation and depth to the top of the carbonate horizon r 2 0 03 p 0 001 parent material and soil texture both play negligible roles in this regression when combined with similar published studies n 1481 r 2 improves slightly r 2 0 31 p 0 001 caution is therefore advised in using this or any previously published regression for inferring paleoprecipitation from paleosols however in the combined data set carbonate horizon bearing soils correlate with a mean annual precipitation of 760 mm p 0 05 thus the presence vs absence of pedogenic calcium carbonate is a good indicator of paleoprecipitation above or below this value

stable oxygen and carbon isotopes of pedogenic carbonate as indicators of plio pleistocene paleoclimate in southern rio grande rift south central new mexico stable oxygen and carbon isotopes of pedogenic carbonate provide a detailed record of paleoclimatic changes from late pliocene through early pleistocene in the rio grande rift of south central new mexico 30 calcic paleosols were sampled at three stratigraphic sections of the fluvial lithofacies of the camp rice formation and one calcic paleosol was sampled from fluvial sediment inset against the camp rice formation paleosols commonly consist of an argillic b horizon bt overlying a calcic bk or petrocalcic km horizon the majority of paleosols consist of state ii morphology calcic horizons although one stage v horizon and five stage iii horizons were also sampled reversal magnetostratigraphy at all four sample sites bracket the age of the paleosol bearing strata between 2 4 and 0 7 ma and allow estimates of the absolute age of individual paleosols three paleoclimatic stages are indicated by the carbon and oxygen isotopic data from south central new mexico the initial stage from 3 1 to 2 5 ma was characterized by the overall lowest values of partial derivative sup 18 o and partial derivative sup 13 c and by an increase in values with decreasing age suggesting high effective moisture and abundant winter precipitation which decreased through time and or relatively low temperature which increased throughmore time the second stage 2 5 1 4 ma displays an increase in partial derivative sup 18 o with decreasing age but no significant change in partial derivative sup 13 c with time suggesting that the effective moisture was nearly constant but that the temperature and or summer precipitation may have increased through time the final stage 1 4 0 7 ma shows an overall increase in both partial derivative sup 18 p and partial derivative sup 13 c with decreasing age corresponding to less effective moisture higher temperature and or greater summer precipitation through time 56 refs 6 figs 2 tabs less

the cretaceous tertiary boundary in the central alberta foothills i stratigraphy the cretaceous tertiary boundary in the rocky mountain foothills occurs within a continental sequence carrying economic coal deposits and known as the coalspur formation this formation occurs between the fluvial brazeau below and paskapoo formations the exact position of the boundary is located at the base of the lowest coal mynheer within the coalspur formation the initiation of coal deposition in the coalspur formation is not a unique event as it is consistent with the cyclic pattern established within the underlying brazeau formation however the magnitude and lateral continuity of coal zone development far exceed those found in the underlying formation the classic shift from a diverse late maastrichtian flora within which angiosperm and especially aquiloid pollen are prominent to a low diversity early paleocene flora dominated by gymnosperm pollen and miospores is documented deviations from most previously recognized floral events at the cretaceous tertiary boundary include 1 san angio

mixed geothermal and shallow meteoric origin of opal and calcite beds in pliocene lower pleistocene axial fluvial strata southern rio grande rift rincon hills new mexico u s a abstract exposed in upper pliocene fluvial strata in the eastern rincon hills and adjacent jornada del muerto basin southern rio grande rift new mexico usa are five laterally continuous beds 0 2 to 1 0 m thick of opal ct which straddle the east rincon hills normal fault four of these opal beds change basinward over 1 km or less to white friable lithofeldspathic sand with opal glaebules and then to microcrystalline calcite the opal and calcite generally replaced fine sand at shallow depths although two beds locally precipitated from standing water 87sr 86sr values 0 71301 to 0 71724 of the opal beds are consistent with precipitation from an advecting high temperature geothermal fluid that flowed through bedrock and or from a high temperature geothermal fluid derived from a deep crustal source carbon and oxygen isotopic values 13cpdb 7 1 to 0 6 18opdb 9 1 to 5 6 of the calcite beds lie between and overlap those of paleozoic carbonate and pliocene paleosol calcite suggesting precipitation from a mixture of a high temperature geothermal fluid that interacted with paleozoic carbonates and shallow meteoric groundwater for which paleosol calcite is a proxy the geothermal fluids are interpreted to have upwelled along the east rincon hills fault flowed laterally at or just below the surface and precipitated opal in response to rapid cooling and evaporation downflow precipitation of opal glaebules occurred as a result of decreasing silica concentrations and perhaps by mixing with shallow meteoric groundwater from which calcite precipitated probably by co2 degassing

dynamics of river aquifer interactions along a chalk stream the river lambourn uk this paper describes the spatial and temporal pattern of groundwater flow accretion to the river lambourn a 234 km2 chalk catchment of the west berkshire downs uk which has been largely unaffected by groundwater abstraction variations in the discharge measured at four fixed gauges in the catchment coupled with information on the length of flowing channel over the period 1983 2001 are used to describe regional patterns in flow accretion mean catchment accretion generally exceeds 0 15 m3 s 1 km 1 but there are significant differences between perennial reaches indicating how the combination of local structural controls and seasonal changes in the drainage net affect flow accretion data from current meter surveys were used to determine the spatial variability in flow accretion 505 paired observations along 12 reaches between 1 and 2 95 km in length indicated a consistent spatial trend in accretion accretion was high in upstream and downstream channel reaches and in middle reaches where dry valleys intersected the main valley a flow accretion index was developed to describe the relationship of flow accretion in each of the 12 study reaches to catchment discharge the relationship varied from a strong positive correlation with catchment discharge two reaches a weak positive correlation three reaches a strong negative correlation two reaches to no relationship to catchment discharge four reaches the results highlight the need to reconsider the usual assumption of uniform or uniformly increasing flow accretion in chalk catchments moreover they emphasize the importance of catchment topography and illustrate how flow accretion in individual reaches may vary between high and low groundwater levels

stable carbon and oxygen isotopes in quaternary soil carbonates as indicators of ecogeomorphic changes in the northern chihuahuan desert usa stable carbon and oxygen isotopes in soil carbonates provide an additional technique for investigating quaternary ecogeomorphic changes in arid and semiarid regions this study presents 13c and 18o values in surface and buried soils in a basin and range region of southern new mexico and west texas three landform categories were investigated for their isotopic content 1 middle piedmont slopes 2 a lower piedmont slope and adjacent playa depressions and 3 an intermontane basin floor soils of the middle piedmont slopes had greatest 13c variability ranging from 0 6 in buried soils to 11 1 pdb in surface soils soils of the basin floor had greatest variability in 18o values ranging from 0 6 to 7 6 pdb fossil pollen patterns roughly paralleled 13c shifts with cheno am pollen exhibiting greatest changes both isotope and pollen data across stratigraphic discontinuities suggest that a conversion from c4 grasses to c3 desert shrubs accompanied holocene erosion

the clumped isotope geothermometer in soil and paleosol carbonate we studied both modern soils and buried paleosols in order to understand the relationship of temperature t c 47 estimated from clumped isotope compositions 47 of soil carbonates to actual surface and burial temperatures carbonates from modern soils with differing rainfall seasonality were sampled from arizona nevada tibet pakistan and india t c 47 obtained from these soils shows that soil carbonate forms in the warmest months of the year in the late morning to afternoon and probably in response to intense soil dewatering t c 47 obtained from modern soil carbonate ranges from 10 8 to 39 5 c on average t c 47 exceeds mean annual temperature by 10 15 c due to summertime bias in soil carbonate formation and to summertime ground heating by incident solar radiation secondary controls on t c 47 are soil depth and shading site mean annual air temperature maat across a broad range 0 30 c of site temperatures is highly correlated with t c 47 from soils following the equation maat c 1 20 t c 47 0 21 72 r 2 0 92 where t c 47 0 is the effective air temperature at the site estimated from t c 47 the effective air temperature represents the air temperature required to account for the t c 47 at each site after consideration of variations in t c 47 with soil depth and ground heating the highly correlated relationship in this equation should now permit mean annual temperature in the past to be reconstructed from t c 47 in paleosol carbonate assuming one is studying paleosols that formed in environments generally similar in seasonality and ground cover to our calibration sites t c 47 0 decreases systematically with elevation gain in the himalaya following the equation elevation m 229 t c 47 0 9300 r 2 0 95 assuming that temperature varied similarly with elevation in the past this equation can be used to reconstruct paleoelevation from clumped isotope analysis of ancient soil carbonates we also measured t c 47 from long sequences of deeply buried 5 km paleosol carbonate in the himalayan foreland in order to evaluate potential diagenetic resetting of clumped isotope composition we found that paleosol carbonate faithfully records plausible soil t c 47 down to 2 5 4 km burial depth or 90 125 c deeper than this and above this temperature t c 47 in paleosol carbonate is reset to temperatures 40 c we observe 40 c as the upper limit for t c 47 in modern soils from soil depths 25 cm and therefore that t c 47 40 c obtained from ancient soil carbonate indicates substantially warmer climate regimes compared to the present or non primary temperatures produced by resetting during diagenesis if representative this limits the use of t c 47 to reconstruct ancient surface temperature to modestly buried 3 4 km paleosol carbonates despite diagenetic resetting of 47 values 18 o and 13 c values of the same deeply buried paleosol carbonate appear unaltered we conclude that solid state reordering or recrystallization of clumping of carbon and oxygen isotopes can occur in the absence of open system exchange of paleosol carbonate with significant quantities of water or other phases

possible connection of polar cap flows to pre and post substorm onset pbis and streamers 1 recent analysis of a short period of observations has led to the hypothesis that enhanced meso scale flows from well within the region of open polar cap field lines may cross the nightside polar cap boundary into the closed field line region and contribute to the triggering of equatorward earthward meso scale flows across the ionospheric equatorial portion of plasma sheet fields lines and lead to pbis and streamers this includes the streamers that have been postulated to bring new plasma equatorward earthward and lead to substorm onset meso scale structure of flow within the polar cap often studied near the dayside polar cap boundary has not previously been generally recognized as significant within the nightside polar cap here we have taken advantage of new capabilities to measure polar cap convection by the resolute bay incoherent scatter radar and the rankin inlet polardarn radar coordinated with themis all sky imager observations to study flow measurements from well within the polar cap to near the polar cap boundary we present evidence that flow structures moving from the polar cap toward the nightside polar cap boundary may be important for triggering the flows that lead to substorm onset streamers the new observations also have given evidence that the flow structures come from deep within the polar cap and have given unexpected evidence that a continuation of flow structures moving from the polar cap toward the nightside polar cap boundary after substorm onset may be important in controlling the poleward expansion and duration of post onset auroral activity

relationship between polar cap patches and field aligned irregularities as observed with an all sky airglow imager at resolute bay and the polardarn radar at rankin inlet 1 simultaneous two dimensional observations of airglow enhancement and radar backscatter from field aligned irregularities fais associated with polar cap patches were conducted the spatial structure of 630 nm airglow from polar cap patches was imaged using an all sky airglow imager at resolute bay canada while backscatter echoes from decameter scale fais were observed using the newly constructed hf polar dual auroral radar network polardarn radar at rankin inlet canada both the airglow enhancement and the radar backscatter appeared within a structured region with the spatial extent of about 500 1000 km the decameter scale fais were found to extend over the entire region of airglow enhancement associated with polar cap patches indicating that the polar patch plasma became almost fully structured soon after initiation within approximately 20 25 min these findings imply that some rapid structuring process of the entire patch area is involved in addition to the primary gradient drift instabilities

day night coupling by a localized flow channel visualized by polar cap patch propagation we present unique coordinated observations of the dayside auroral oval polar cap and nightside auroral oval by three all sky imagers two super dual auroral radar network superdarn radars and defense meteorological satellite program dmsp 17 this data set revealed that a dayside poleward moving auroral form pmaf evolved into a polar cap airglow patch that propagated across the polar cap and then nightside poleward boundary intensifications pbis superdarn observations detected fast antisunward flows associated with the pmaf and the dmsp satellite whose conjunction occurred within a few minutes after the pmaf initiation measured enhanced low latitude boundary layer precipitation and enhanced plasma density with a strong antisunward flow burst the polar cap patch was spatially and temporally coincident with a localized antisunward flow channel the propagation across the polar cap and the subsequent pbis suggests that the flow channel originated from dayside reconnection and then reached the nightside open closed boundary triggering localized nightside reconnection and flow bursts within the plasma sheet

geochemical and 222rn constraints on baseflow to the murray river australia and timescales for the decay of low salinity groundwater lenses the distribution of 222rn activities and major ion concentrations show that during low river flows characteristic of the recent drought conditions the middle reaches of the murray river northern victoria were a predominantly gaining system at low river levels may 2009 may 2010 and were variably gaining and losing at higher river levels november 2009 the location of gaining and losing reaches are partially governed by the position of the river with respect to the edge of its floodplain gaining reaches occur where the floodplain narrows or where the river is adjacent to the steep slopes at the floodplain margin cumulative inflows along this 350km stretch of the river estimated from 222rn activities were 320 1500m 3 day in november 2009 and 560 4300m 3 day in may 2010 the relatively large uncertainty reflects the heterogeneous and poorly constrained groundwater 222rn activities major ion variations notably cl concentrations and na ca ratios correlate with 222rn activities and may be used as indicators of groundwater inflows baseflow contributed 1 of the total water to this part of the river and consequently has little impact on river water quality nevertheless the groundwater inflows remove water from low salinity groundwater lenses that underlie the river and during the drought conditions these lenses were degrading these reaches of the river murray are an example of a system that transitioned from being dominantly losing to being variably gaining due to diminishing surface water flows

classification of paleosols despite increased interest in paleosols during the past decade no satisfactory classification is in current use presented here is a largely descriptive classification system that utilizes those pedogenic features that have the highest preservation potential in the rock record emphasized in the classification are morphological and mineralogical features that are easily recognizable in the field and through the petrographic microscope the classification is based on evaluation of the relative prominence in a paleosol of six pedogenic features or processes organic matter content horizonation redox conditions in situ mineral alteration illuviation of insoluble minerals compounds and accumulation of soluble minerals the most prominent of these six features processes provides the key to classifying a paleosol into one of nine orders four of the order names are borrowed from soil taxonomy histosol spodosol oxisol vertisol whereas the other five order names are presented here for the first time calcisol gypsisol gleysol argillisol protosol the orders may be preceded by one or more subordinate modifiers that describe other important features of the paleosol the classification is relatively easy to apply to the rock record and should enhance communication and aid in the standardization of terminology

a dynamical model of high latitude convection derived from superdarn plasma drift measurements 1 a discrete set of climatological patterns of high latitude ionospheric convection are derived using line of sight plasma drift data from the super dual auroral radar network superdarn the patterns are derived independently for the northern hemisphere and southern hemisphere and for varying solar wind interplanetary magnetic field imf and dipole tilt angle conditions by interpolating between discrete patterns a dynamical model of convection is obtained which can uniquely specify the high latitude electrostatic potential distribution for a wide range of solar wind imf and dipole tilt parameter values accounting for solar wind velocity dependencies in convection leads to better resolving the large scale convection pattern as compared to previous statistical models based on superdarn data it is shown that the mesoscale features of the climatological model compare favorably to the features seen in instantaneous patterns of convection observed with superdarn comparison of the model to other statistical or empirical models derived from ground and space based measurements shows good agreement with most models

assessing pedogenic calcite stable isotope values can positive linear covariant trends be used to quantify palaeo evaporation rates abstract palaeoclimate models suggest enhanced evaporation rates in subtropical regions 15 30 latitude during greenhouse world conditions however there are no empirical data to support these estimates laboratory evaporation experiments have shown that calcites precipitated from variably saturated solutions yield a positive linear covariant trend plct in 18 o calcite versus 13 c calcite values the goal of the present controlled laboratory experiments is to develop a method to quantify regional palaeo evaporation rates from palaeosol calcrete plcts samples of powdered caco 3 were dissolved in de ionized water in pressure sealed containers with a range of elevated atmospheric p co 2 concentrations for 24 h the solution was then allowed to evaporate completely from an open container within an incubator with the time of calcite crystallization noted and aliquots removed for analysis every 24 h the precipitated calcite produced an array of 18 o calcite versus 13 c calcite values that fall upon a plct projected from a theoretical meteoric calcite line mcl water analyses yielded 18 o water enrichments from an initial value of 4 75 vsmow ranging up to between 10 0 and 14 8 the experimental results show that solutions formed under higher p co 2 conditions precipitated calcite very early on during evaporation and thus have 18 o calcite and 13 c calcite values that are slightly enriched relative to the mcl the solutions that formed under low p co 2 conditions precipitated calcite after much of the fluid had evaporated and thus yield more enriched 18 o calcite and 13 c calcite values repeat trials with varying temperature and relative humidity show that the plct is steeper under both higher temperature and low relative humidity the wide range of p co 2 temperature and relative humidity conditions used simulate meteoric phreatic and meteoric vadose conditions that may affect a calcrete horizon over time during numerous dissolution precipitation reactions the results of these experiments show that a dominant factor in the precipitation of vadose calcite is the saturation state of the fluid with respect to caco 3 while the primary factors affecting the magnitude and steepness of the plct are vadose zone temperature relative humidity the starting 18 o water value and saturation state of the fluid with respect to caco 3 since the p co 2 of the rooting zone is cross controlled by the local soil and surface ecology the magnitude of the plct enrichment may not be a direct proxy for palaeo evaporation rates

cretaceous climate a comparison of atmospheric simulations with the geologic record abstract atmospheric simulations using realistic cretaceous geography 100 million years ago suggest that paleography is an important factor governing the nature of the circulation the simulated cretaceous atmospheric circulations are markedly different both from the present day atmospheric circulation and from the classical hypotheses of a weaker circulation and poleward displacement of circulation features e g the subtropical high therefore they pose specific questions which can be tested against the geologic record aspects of the cretaceous simulations are verified in comparisons with the geologic record the simulations serve to guide areas of future paleoclimatic research and to formulate better the nature of the problem of warm equable climates

climate change across continental sequence boundaries paleopedology and lithofacies of iglesia basin northwestern argentina subdivision of sedimentary rocks into genetically related sequences reflects the interaction between the extrinsic and intrinsic processes that affect a basin s accommodation potential as well as its environment in nonmarine settings sequence bounding surfaces are often difficult to locate and several causal mechanisms for sequences e g tectonism climate change and autogenic variability combine in complex and still poorly understood ways here we draw upon paleosols as sources of evidence for causes of sequence boundaries in the upper miocene lower pliocene continental iglesia wedgetop basin san juan province argentina stable isotope compositions 13c and 18o clay mineralogy inorganic carbon weight percentages and micromorphologic features of paleosols that span 9 0 4 6 ma reveal environmental conditions concurrent with the development of ten continental stratigraphic sequences charaetcristics of compound pedofacies and regionally recognizable abrupt vertical lithofacies changes suggest fluctuations in both accumulation rate and climate across sequence boundaries and between structural subbasins we interpret that the iglesia basin strata accumulated under conditions that were generally semiarid with seasonal precipitation isotopic ratios and soil inorganic carbon weight percentages indicate increased aridity at 6 9 and 5 2 ma each a time of sedimentary hiatus notable enrichment of the 13c signal at 6 9 ma also suggests the onset of dominance of c4 plant biomass in northwestern argentina in combination with seismic data we interpret that four of the ten sequence boundaries formed during intervals of marginal surface uplift concurrent with greater aridity circumstances that led to erosion of proximal strata and starved the central basin of sediment input resulting in hiatuses in sediment accumulation

the behavior of u and th series nuclides in groundwater groundwater has long been an active area of research driven by its importance both as a societal resource and as a component in the global hydrological cycle key issues in groundwater research include inferring rates of transport of chemical constituents determining the ages of groundwater and tracing water masses using chemical fingerprints while information on the trace elements pertinent to these topics can be obtained from aquifer tests using experimentally introduced tracers and from laboratory experiments on aquifer materials these studies are necessarily limited in time and space regional studies of aquifers can focus on greater scales and time periods but must contend with greater complexities and variations in this regard the isotopic systematics of the naturally occurring radionuclides in the u and th decay series have been invaluable in investigating aquifer behavior of u th and ra these nuclides are present in all groundwaters and are each represented by several isotopes with very different half lives so that processes occurring over a range of time scales can be studied table 1 within the host aquifer minerals the radionuclides in each decay series are generally expected to be in secular equilibrium and so have equal activities see bourdon et al 2003 in contrast these nuclides exhibit strong relative fractionations within the surrounding groundwaters that reflect contrasting behavior during release into the water and during interaction with the surrounding host aquifer rocks radionuclide data can be used within the framework of models of the processes involved to obtain quantitative assessments of radionuclide release from aquifer rocks and groundwater migration rates the isotopic variations that are generated also have the potential for providing fingerprints for groundwaters from specific aquifer environments and have even been explored as a means for calculating groundwater ages view this table table 1 radionuclides important in groundwater studies the highly fractionated nature of the

gps scintillation and irregularities at the front of an ionization tongue in the nightside polar ionosphere in this paper we study a tongue of ionization toi on 31 october 2011 which stretched across the polar cap from the canadian dayside sector to svalbard in the nightside ionosphere the toi front arrived over svalbard around 1930 ut we have investigated gps scintillation and irregularities in relation to this toi front this is the first study presenting such detailed multi instrument data of scintillation and irregularities in relation to a toi front combining data from an all sky imager the european incoherent scatter svalbard radar the super dual auroral radar network hankasalmi radar and three gps scintillation and total electron content tec monitors in longyearbyen and ny alesund we observe bursts of phase scintillation and no amplitude scintillation in relation to the leading gradient of the toi spectrograms of 50hz phase measurements show highly localized and variable structuring of the toi leading gradient with no structuring or scintillation within the toi or ahead of the toi

geochemical model of δ18o of pedogenic calcite versus latitude and its application to cretaceous palaeoclimate abstract in the absence of a systematic global data base on the 18 o composition of modern soil calcite predicted isotopic values are calculated as a function of latitude between 60 and 20 using 18 o of summer and winter meteoric water ambient soil temperature equal to either measured values in asia or mean annual temperature and 0 10 20 and 30 evaporation of soil water the results show overall higher isotopic values for summer versus winter precipitation but steeper positive slopes for the winter precipitation curves where soil temperature is equated to mean annual temperature the summer precipitation curves are nearly flat at high latitudes and have a negative slope at low latitudes in all cases the 18 o values increase with increasing percent evaporation of soil water oxygen isotopic data for early aptian and late maastrichtian cretaceous palaeosol calcite as a function of palaeolatitude of the western interior of north america plot in the modern winter precipitation field which along with vertic features may suggest a winter wet palaeoclimate steeper positive slopes for the cretaceous curves compared to the modern curves may be attributable to greater latitudinal gradients in mean annual temperature and soil temperature in the cretaceous compared to today and or to a greater degree of evaporation in cretaceous soils at low latitudes compared to the modern earth distinguishing between these possibilities will require a more complete understanding of the variables that affect oxygen isotopes in pedogenic calcite as well as better cretaceous terrestrial palaeoclimate proxies with which to compare the isotopic data

shifts in late paleozoic atmospheric circulation over western equatorial pangea insights from pedogenic mineral δ18o compositions the d 18 o values of pedogenic calcites phyllosilicates and iron oxyhydr oxides from fossil soils throughout the southwestern united states show systematic paleolatitudinal and temporal trends that indicate a significant change in soil moisture conditions and atmospheric circulation patterns over southwestern euramerica throughout latest pennsylvanian and early permian time a progressive depletion of as much as 6 in mineral 18 o values with increasing distance northward to 108 of the paleoequator indicates a weakening or disruption of zonal easterly flow over the study area by latest pennsylvanian time furthermore elevated d 18 o values suggest a proximal source of paleoprecipitation over the study area perhaps due to initiation of reversed equatorial flow over tropical southwestern euramerica coupling of the geographic and temporal trends defined by pedogenic mineral d 18 o values with those defined by climatically sensitive paleosol pedotypes in the study area along with overall elevated mineral d 18 o values provides some of the strongest evidence that northern hemisphere monsoonal circulation was well established over pangea by early permian time

an isotopic study of paleosol carbonates from olduvai gorge the isotopic composition of paleosol carbonates from olduvai gorge can be used to give estimates of the paleoclimatic history of east africa during the plio pleistocene oxygen isotopes are indicative of major changes in the isotopic composition of meteoric water while carbon isotopes are indicative of major changes in the fraction of biomass using the hatch slack c4 photosynthetic pathway three major periods of climatic change in this terrestrial setting occurred at about 1 67 1 3 and 0 6 myr these involved major changes in flora as well as major changes in the isotopic composition of meteoric water overall the climate has become warmer and more arid over the past 2 2 myr

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

oxygen and carbon stable isotope composition of authigenic carbonates in loess sequences from the carpathian margin and podolia as a palaeoclimatic record abstract samples were collected from the outcrops situated in the north and east of the carpathian margin in the transition zone between the area of loess covers of eastern and western europe the chosen localities include two zones of temperate climate with slightly different prevailing wind directions these loess palaeosol sequences formed and develop in different time intervals early quaternary epoch podolia ukraine and late quaternary epoch carpathian foothills poland the isotopic analysis was carried out on many types of authigenic soil carbonates including nodules rhizoliths rhizocretions calcified root cells and bioclasts the carbon isotopic compositions 13 c of different types vary markedly these differences seem to be more important than the variations within one type of carbonate at a particular section the 13 c values for authigenic carbonate cements rhizoliths rhizocretions and nodules vary in a narrow range from about 11 to 8 suggesting that calcite cements were precipitated under roughly similar conditions with a considerable supply of co 2 derived from biomineralization of organic matter predominantly from c 3 plants the 18 o record of the calcite cements within the upper quaternary deposits exhibits relatively slight variability suggesting that 18 o values in soil water were homogeneous the significant depletion of 13 c as well as 18 o in calcite from calcified root cells 12 and 7 respectively and to a lesser extent from calcitic globules with respect to calcite cements points to different environments of formation the morphology of calcite crystals replacing root cells and their carbon and oxygen isotopic composition indicate that they may precipitate inside the root cells from fluids with organic compounds in general the temperature reconstructions yield an average mat about 11 c for the upper quaternary sediments deposited during mis 2 the estimated mat for sediments of mis 3 5 range from 12 to 14 c mean annual temperatures estimated for the lower quaternary of podolia fall in the range from 9 to 11 c with two single minimums about 7 c probably corresponding to short lived environmental changes the mat curve throughout the lower part of lower quaternary is more variable and shows several local shifts up to 3 c

radon in groundwater a tool to assess infiltration from surface waters to aquifers we measured the concentrations of natural 222rn half life 3 8 days in groundwater at three sites in switzerland here groundwater is recharged mainly by river water upon infiltration and movement in the ground the radon concentration in the water increases by more than two orders of magnitude to reach a steady state this increase was found at two of the three sites at the site of main interest we used the ingrowth of radon between the river and nearby observation wells to estimate groundwater residence times of up to about four half lives we assumed that the ingrowth of radon can be described by the growth law of radioactivity that the progenitors of radon 226ra 238u are homogeneously distributed in the aquifer and that the freshly infiltrated water is not mixed significantly with older groundwater a linear regression through the data at the site of main interest yielded an average flow velocity of 4 6 m 1 which confirms earlier tracer observations radon accumulates to higher concentrations when the top soil layer is frozen or exhibits a high moisture content during these conditions the radon data cannot be used for dating purposes

structural kinematics and depositional history of a laramide uplift basin pair in southern new mexico implications for development of intraforeland basins the kinematic and erosional history of the rio grande uplift a large northwest trending basement involved thrust bounded block uplift of laramide age latest cretaceous early tertiary in south central new mexico is documented by clastic rocks that accumulated in the complementary love ranch basin the synorogenic to postorogenic mcrae and love ranch formations are as much as 1460 m thick they filled the love ranch basin and onlapped the rio grande uplift present outcrops of the two formations cover an area of 100 km2 and reveal the stratigraphic architecture of the basin fill in three dimensions lithofacies distribution clast size and composition paleoflow data syndepositional structures nature of the basal unconformities and ages of basin fill provide essential data for constraining uplift history laramide shortening began between campanian and latest maastrichtian time and initially created open symmetrical northwest trending folds as well as a broad approximately symmetrical uplift this incipient rio grande uplift was capped by upper cretaceous volcanic rocks of intermediate and silicic composition which were the primary source of volcanic detritus in the latest cretaceous paleocene mcrae formation at this stage of uplift the northeastern flank dipped gently northeastward away from the crest and served largely as a sediment transport surface mcrae strata accumulated only on distal parts of the surface in an embryonic love ranch basin to the northeast following an interruption in tectonism lasting as much as 10 m y renewed shortening in paleocene time elevated the rio grande uplift and formed the love ranch basin at least 900 m of upward fining clastic love ranch strata of paleocene eocene age accumulated in the basin the love ranch lithofacies record a gradual southwestward shift of alluvial fan depocenters which resulted from growth of basin margin structures and increasing basin asymmetry syndepositional synclines and angular unconformities record the growth of both intrabasinal folds and basin margin thrusts clast compositions document progressive erosional unroofing of the rio grande uplift from upper cretaceous volcanic rocks into precambrian granite and metamorphic rocks canyons 0 4 km deep locally drained the uplift and maximum topographic relief may have approached 2 km by late eocene time love ranch piedmont slope deposits onlapped the uplift burying all but the higher granite peaks at this stage the love ranch basin broadened and was the site of broad alluvial plains crossed by braided rivers draining to saline lakes our analysis of syntectonic sedimentary rocks in the love ranch basin supports recent models of evolution of laramide basement involved block uplifts in which early stages produce approximately symmetrical structures and sediment derived from the uplift is transported across most of the uplift flank to be deposited in a distal setting at this stage the future footwall of uplift boundary faults dips basinward in a ramp like fashion providing a sediment transport surface as boundary thrust faults and fault propagation folds evolve and grow basin asymmetry rapidly develops causing depocenters to shift toward footwall positions near the overthrust margins this evolution from symmetrical to asymmetrical structures is reflected in an overall upward fining sequence in the basin fill

in situ measurement of a newly created polar cap patch 1 the investigation of cusp irregularities 2 sounding rocket was launched 5 december 2008 at 1035 ut we present an overview of the associated solar wind and auroral conditions and we look in detail at the relationship between poleward moving auroral forms pmafs and the creation of polar cap patches using ground based optical and radar data as well as in situ data from the rocket payload the solar wind was found to be dominated by a stable interplanetary magnetic field imf bz 0 situation the aurora was characterized by a series of pmafs throughout the period of interest associated with each pmaf were polar cap patches seen to emerge from the most poleward location of the pmafs on the basis of the available data we present a conceptual model explaining the creation of the polar cap patches under the given solar wind and ionospheric conditions

first in situ measurements of hf radar echoing targets 1 the sounding rocket investigation of cusp irregularities 2 ici 2 was launched into the cusp ionosphere over svalbard to investigate the production of decameter scale irregularities in the electron plasma associated with hf radar backscatter the main mission objective was to obtain high resolution measurements of decameter scale electron plasma irregularities and to quantify the growth rate for the gradient drift instability gdi at the 5 7 khz sampling rate of the absolute density measurements ici 2 has provided the first documentation in terms of absolute electron density measurements of how 10 m structures are located on km scale electron density gradients ici 2 traversed a cusp electron density structure created by ongoing soft precipitation 10 m scale irregularities were generated at km scale density gradients the estimated growth time for the gdi process was 10 50 seconds

the mechanism of 234u238u activity ratio enhancement in karstic limestone groundwater departamento de petrologia e metalogenia universidade estadual paulista campus de rio claro unesp sao paulo

upper jurassic lower cretaceous morrison and cedar mountain formations ne utah nw colorado relationships between nonmarine deposition and early cordilleran foreland basin development abstract sedimentologic stratigraphic and petrologic analysis of the upper jurassic lower cretaceous morrison and cedar mountain formations of utah and colorado provides information on the timing and nature of early cordilleran foreland basin development the morrison formation can be subdivided into three depositional facies assemblages 1 lower progradational shallow marine lacustrine fluvial and eolian facies deposited during oxfordian kimmeridgian retreat of the stump sundance sea 2 a middle assemblage containing sandy gravelly braided fluvial deposits which are overlain by meandering fluvial channel and overbank facies and 3 an upper assemblage of laterally stable low sinuosity fluvial channel facies deposited during tithonian early neocomian time the upper part of this assemblage shows evidence of alteration and early diagenesis related to development of an early cretaceous unconformity the overlying cedar mountain formation is subdivided into two facies assemblages 1 the neocomian buckhorn conglomerate was deposited by northeast trending sandy gravelly braided rivers that were incised into the underlying morrison formation 2 an upper assemblage containing laterally stable low sinuosity fluvial channel facies deposited during late neocomian albian time the base of the unit contains a thick calcrete zone that formed during an unconformity following buckhorn deposition morrison and cedar mountain formation sandstones contain three petrofacies a feldspar rich lower morrison petrofacies qmflt 70 19 11 and chert rich upper morrison and buckhorn cedar mountain petrofacies qmflt 54 5 41 and 69 4 27 respectively sandstone composition and paleocurrent data indicate a cordilleran source area composed of proterozoic paleozoic and mesozoic sedimentary rocks the morrison formation and buckhorn conglomerate were deposited in the back bulge depozone of the late jurassic cordilleran foreland basin system and onlapped a flexural forebulge located in central utah late neocomian eastward migration of the forebulge uplifted areas in eastern utah producing an unconformity while the foredeep in central utah underwent flexural subsidence the upper part of the cedar mountain formation represents overfilling of the foredeep and deposition above the forebulge

magnetostratigraphic chronology of cretaceous to eocene thrust belt evolution central utah usa the axhandle basin in central utah is a piggyback basin that formed above the gunnison thrust system the basin contains 1 km of upper cretaceous to eocene strata of the north horn and lower flagstaff limestone formations a significantly more exact chronology based on magnetic polarity stratigraphy has been developed for the basin filling strata the new data provide a detailed temporal framework for the interpretation of the depositional and tectonic evolution of the basin during chrons 33 21 75 49 ma tectonic subsidence curves and stratigraphie relations along the eastern basin margin define two episodes of motion on the gunnison thrust system the majority of tectonic shortening on the system occurred between 83 75 ma and caused widespread non deposition within the axhandle basin a second episode of motion in detail comprising of four separate periods of backthrusting occurred between 70 60 ma the canyon range pavant and nebo thrust sheets were emplaced 30 50 km to the west of the axhandl

hydrodynamics of floodplain wetlands in a chalk catchment the river lambourn uk variations in floodplain channel water levels and valley floor groundwater levels measured in piezometers and boreholes are examined at selected points along the course of the river lambourn a chalk river in southern england a local alluvial gravel aquifer in the valley bottom is associated with numerous small wetlands that extend over much of the river s perennial profile variations in hydraulic gradient between local borehole levels and or floodplain channel water levels are described for three sites in the seasonal section of the channel at bockhampton east garston and west shefford the results indicate that observed groundwater levels are closely associated with flows from discrete springs at the margins of the channel and floodplain however as the floodplain widens and the alluvial gravel aquifer increases in size the gravel aquifer accounts for a substantial down valley component of groundwater flow with a diffuse vertical water flux in the lower catchment the exchange of flows between the gravel aquifer and the river enables some attenuation of floodplain water table variability providing a stable hydrological regime for valley bottom wetlands catchment controls upon the local valley bottom wetland regime are demonstrated with the application of a simple groundwater model developed using modflow the model is used to simulate groundwater discharge to the river in the upper and lower catchment in addition to the water level regime at selected points in the valley bottom in the lower catchment the results demonstrate the importance of taking catchment scale water flow into account when managing isolated wetlands in a permeable catchment

decay of polar cap patch 1 we report an event in which a polar cap patch was detected with an all sky imager asi at resolute bay canada 74 73 n 265 07 e aacgm latitude 82 9 on the nightside the patch stopped its antisunward motion associated with a northward turning of interplanetary magnetic field and stayed within the field of view of the asi for more than 1 h when the patch stagnated its luminosity decreased gradually which allows us to investigate how the patch plasma decayed in a quantitative manner the decay of the patch can be quantitatively explained by the loss through recombinations of o with ambient n2 and o2 molecules if we assume the altitude of the optical patch to be around 295 km the derived altitude of the patch around 295 km is much higher than the nominal value at 235 km obtained from the msis e90 and iri 2007 models indicating that climatological models such as iri are not suitable for describing the actual density profile of patches this is probably because the loss process was much faster in the lower altitude part of the patch thus the peak altitude of the patch increased as it traveled across the polar cap because of rapid recombination at the bottomside of the f region this suggests that we should employ higher emission altitude when we investigate optical patches transported deep into the nightside polar cap such information is important when we compare the optical data with other instruments such as coherent radars and gps scintillation measurements by mapping the all sky image on the geographic coordinate system with an assumption of the patch emission altitude

radon in chalk streams spatial and temporal variation of groundwater sources in the pang and lambourn catchments uk summary variations in dissolved 222 rn radon concentrations in rivers and groundwater are observed in the cretaceous chalk catchments of the pang and lambourn stream radon concentrations and flow data were used to model radon inputs to rivers from groundwater with the modelled radon input concentrations c i varying between 0 2 bq l 1 and 3 8 bq l 1 consistent with measured groundwater values groundwater in both catchments was found to have higher and more variable radon concentrations 2 12 bq l 1 in the near surface weathered horizons compared to a consistent 1 bq l 1 from the solid chalk the variations in c i can be related to flow generation pathways and hydrological events in the lambourn the radon budget is controlled by diffuse groundwater inputs supporting the hypothesis that the alluvial aquifer plays a greater role during periods of high accretion the pang is more complex than the lambourn having a combination of diffuse and point source inputs with spring inputs dominating both flow and radon signatures in the lower part of the catchment significant temporal and spatial variations were determined for c i in both catchments reflecting their differing geologies and flow regimes one use of radon in hydrology is the determination of groundwater discharges to rivers but the observed variations in c i mean this approach may not be appropriate to all situations and that changes in source need further evaluation nonetheless radon is shown to be a useful tracer of flow paths and processes within these catchments

using 222rn to examine groundwater surface discharge interaction in the rio grande de manati puerto rico 222rn was used in the karst drainage basin of the rio grande de manati in puerto rico to study groundwater surface flow relationships locations of groundwater influx along two sections of the rio grande de manati were identified the 222rn measurements were used together with stream discharge data in a mass balance equation to quantify the groundwater inputs the investigation established that both of the sections of the rio manati surveyed not only gained groundwater but lost surface flow it was calculated that the river gained about 1 2m3s 1 and lost 0 5m3s 1 to the aquifer between ciales and united states geological survey gauging station 5 between united states geological survey gauging stations 6 and 7 groundwater influx and stream flow loss occurred simultaneously with groundwater inputs equalling surface discharge losses of 4m3s 1 the study successfully demonstrated the innovative application of 222rn as a geochemical tracer in examining groundwater surface flow relationships in a karst system

plasma convection in the vicinity of the dayside cleft experiments conducted with the chatanika alaska incoherent scatter radar observed the ionospheric convection pattern equatorward of the noontime cleft there plasma transport is characterized by low speed convergence toward a meridian centered somewhat before noon and rotation of the flow into a poleward direction at higher latitudes for undisturbed conditions there is only weak convection at noon at these latitudes but the eastward electric field reaches a maximum of 15 mv m 2 4 hours before and after noon at latitudes between 70 and 74 during active conditions at the peak of the solar cycle the ionospheric cleft was located within the chatanika field of view on several occasions a longitudinally narrow region of rapid poleward convection near noon was not observed rather poleward flow occurred over a 3 4 hour spread of local time for disturbed conditions the prenoon and postnoon regions of plasma entry into the polar cap were enhanced and an eastward electric field of 25 mv m was seen across the 2 hours of local time around noon high density f region plasma was observed convecting poleward through the cleft from a source at lower latitudes in the afternoon sector such plasma seen at very high latitudes within the polar cap serves as a tracer of the convection pattern away from the cleft

quantifying groundwater discharge to cockburn river southeastern australia using dissolved gas tracers 222rn and sf6 groundwater discharge to the cockburn river southeast australia has been estimated from comparison of natural 222rn activities in groundwater and river water interpreted using a numerical flow model that simulates longitudinal radon activities as a function of groundwater inflow hyporheic exchange evaporation gas exchange with the atmosphere and radioactive decay an injection of sf6 into the river to estimate the gas transfer velocity assisted in constraining the model previous estimates of groundwater inflow using 222rn activities have not considered possible input of radon due to exchange between river water and water in the hyporheic zone beneath the streambed in this paper radon input due to hyporheic exchange is estimated from measurements of radon production by hyporheic zone sediments and rates of water exchange between the river and the hyporheic zone total groundwater inflow to the cockburn river is estimated to be 18500 m 3 d although failure to consider hyporheic exchange would cause overestimation of the volume of groundwater inflow by approximately 70 copyright 2006 by the american geophysical union

storm time plasma transport at middle and high latitudes associated with the large scale enhancement of the ionospheric convection electric field during disturbed geomagnetic conditions solar produced f region plasma is transported to and through the noontime cleft from a source region at middle and low latitudes in the afternoon sector as a result of the offset between the geomagnetic and geographic poles the afternoon sector region of strong sunward convection is shifted to increasingly lower geographic latitude throughout the interval between 12 ut and 24 ut a snowplow effect occurs in which the convection cell continually encounters fresh corotating ionospheric plasma along its equatorward edge producing a latitudinally narrow region of storm enhanced plasma density sed and increased total electron content which is advected toward higher latitudes in the noon sector the millstone hill incoherent scatter radar regularly observes sed as a spatially continuous large scale feature spanning local times between noon and midnight and at latitudes between the polar cap and its mid or low latitude source region for local times away from noon the latitude of most probable sed occurrence moves equatorward by 6 for an increase of 2 in the kp index during strong disturbances the topside sed is observed to be convecting sunward at 750 m s 1 with a flux of 1014 m 2 s 1 this feature accounts for the pronounced enhancement of ionospheric density near dusk at middle latitudes observed during the early stages of magnetic storms called the dusk effect and constitutes a source for the enhanced f region plasma observed in the polar cap during disturbed conditions

late paleocene high laramide ranges in northeast wyoming oxygen isotope study of ancient river water abstract the distribution and initial timing of the establishment of high surface elevations in the rocky mountains during the early cenozoic remain controversial despite the importance of these data in testing tectonic models for this region we track the timing and distribution of high elevation in the rocky mountains during the late cretaceous early eocene by examining annual and seasonal 18o values of the ancient river water which are calculated from the 18o values of well preserved freshwater bivalve shells in the powder river basin of the eastern laramide province the 18o values of the ancient river water vary between 23 0 and 8 0 smow in both seasonal and annual records in the late paleocene early eocene the large variation suggests that the ancient rivers were fed yearly or seasonally by snowmelt from highlands of 4 5 1 3 km this can be explained by the existence of the bighorn mountains and black hills with a drainage pattern similar to the present in northeast wyoming the 18o values of ancient river water along the front of the sevier thrust belt generally follow a trend from lower values in north 14 2 1 4 in the early paleocene crazy mountains basin to higher values in south 11 1 0 8 in the late paleocene bighorn basin and 7 1 1 6 in the early eocene washakie basin the variations within each basin are relatively small these rivers most likely rise in the sevier thrust belt and may reflect highland elevation of 1 2 km the 18o values in the alberta foreland and williston basin are very low 20 5 in the late cretaceous indicating the rivers were fed by snowmelt from the canadian rocky mountains of 4 3 1 0 km high the attainment of high elevation in the eastern laramide province prior to the western province could be explained by southwestward progression of back thrusts soled into an earlier east directed master detachment which may be formed by the westward rollback of subducted shallow slab

mapping and quantifying groundwater inflows to deep creek maribyrnong catchment se australia using 222rn implications for protecting groundwater dependant ecosystems abstract understanding groundwater inflows to rivers is important in managing connected groundwater and surface water systems and for protecting groundwater dependant ecosystems this study defines the distribution of gaining reaches and estimates groundwater inflows to a 62 km long section of deep creek maribyrnong catchment australia using 222 rn during summer months deep creek ceases to flow and comprises a chain of ponds that 18 o and 2 h values major ion concentrations and 222 rn activities imply are groundwater fed during the period where the river flows the relative contribution of groundwater inflows to total river discharge ranges from 14 at high flow conditions to 100 at low flows that the predicted groundwater inflows account for all of the increase in discharge at low flow conditions lends confidence to the mass balance calculations near continuous 27 week 222 rn monitoring at one location in the middle of the catchment confirms the inverse correlation between river discharge and relative groundwater inflows and also implies that there are limited bank return flows variations in groundwater inflows are related to geology and topography high groundwater inflows occur where the river is at the edge of its floodplain adjacent to hills composed of basement rocks or flowing through steep incised valleys understanding the distribution of groundwater inflows and quantifying the contribution of groundwater to deep creek is important for managing and protecting the surface water resources which support the endangered yarra pygmy perch

the correlation between 18o 16o ratios of meteoric water and surface temperature its use in investigating terrestrial climate change over geologic time abstract correlations between mean annual temperature mat and the weighted average oxygen isotope composition of yearly precipitation 18opt are well known but the utility of modern relations to make reliable estimates of temperature change over geological time is uncertain this question has been addressed by using seasonal subsets of the global data base of temperature and isotopic measurements to represent two different climate modes a comparison of middle to high latitude 18opt temperature relations for each climate mode reveals 1 a significant offset between them and 2 a difference in the strength of their correlations the offset in relations is due to differences in temperature and water vapor budget in the tropics and can lead to serious underestimates of temperature change differences in the strength of correlations arise from the influence of climate mode specific non temperature factors on 18opt the overall result is that no single relation can be used in all cases to make unambiguous temperature estimates using a temporal record of 18opt values one way to overcome these problems is to reconstruct 18opt temperature relations for the time periods being investigated if an appropriate proxy for 18opt is available it may also be possible to estimate temperature without relying on 18opt temperature relations a promising alternative to these options is to use records of 18opt to test predictions of global climate models an approach that may allow a reliable and more complete reconstruction to be made of climate change over geologic time

sedimentological and palynological evidence of regional climatic changes in the campanian to paleocene sediments of the rocky mountain foothills canada abstract evidence of paleoclimatic variations in the upper campanian to lower paleocene post wapiabi sequence of strata is visible both laterally between the central and southern foothills and vertically in the stratigraphic record these differences are expressed by the distribution of climatically sensitive sediments i e coal and caliche and associated palynological assemblages within floodplain facies as well as by changes in the style of fluvial channels the interpretation of a semi arid environment for mature caliche paleosols is supported by the impoverished character of the associated palynological assemblages both in terms of diversity and the number of specimens recovered and by the conspicuous presence of classopollis the lateral extent of the semiarid floodplain facies and associated broad and mobile channel deposits is limited to the southern part of the basin no signs of a caliche facies have been found in the post wapiabi strata of the central foothills instead some of the floodplain deposits associated with meandering streams in this part of the basin contain numerous thick coal bearing intervals the relative climatic differences between the more humid central part and the drier southern part of the basin prevailed throughout the entire post wapiabi interval as this cannot be satisfactorily explained by the position of the sea shore or by orographic influences alone there was probably another external factor this could have been the pattern of atmospheric circulation such as that responsible for the present day climatic differences existing between the southern and central foothills semiarid floodplain facies occur at two levels in the stratigraphic column of the southern foothills in the late campanian belly river formation and in the upper maastrichtian to lower paleocene willow creek formation they correspond to regressive episodes of the epicontinental seaway intervening between these semiarid floodplain facies are the marine shales of the bearpaw formation and both overlying and underlying them thin coal beds these represent recurrent periods of swamp growth and peat accumulation in back barrier environments lagoon fill and supratidal marsh respectively because of the proximity of these swamps to the sea shore it is difficult to assess the influence of climate on the relative humidity of these settings on strictly sedimentological grounds however the terrestrial components of the palynological assemblages recovered from these marginal marine settings and correlative lacustrine sediments containing fresh water stromatolites but no coal in the central foothills are in sharp contrast with the impoverished assemblages known from the caliche facies the former are prolific diverse and contain a number of triprojectate pollen species which indicate a relatively humid climate during the latest campanian time

carbon dioxide dynamics driven by groundwater discharge in a coastal floodplain creek summary dissolved carbon dioxide co 2 may be highly enriched in groundwater however the contribution of groundwater discharge as a source of co 2 to rivers estuaries and coastal waters is poorly understood we performed high resolution measurements of radon 222 rn a natural groundwater tracer and the partial pressure of co 2 p co 2 in a highly modified tidal creek and estuary north creek richmond river new south wales australia to assess whether co 2 in surface waters was driven by groundwater discharge a spatial survey revealed increasing 222 rn activities up to 17 3 dpm l 1 and p co 2 up to 11 151 atm in the upstream direction the enrichment occurred in a drained coastal acid sulphate soil wetland upstream of a mangrove forest time series experiments 24 h were performed at two stations upstream and downstream of the p co 2 enrichment area upstream measurements demonstrated a significant correlation between p co 2 and 222 rn while downstream values resulted in a significant inverse relationship between p co 2 and dissolved oxygen apparently as a result of respiration in nearby mangroves measurements taken 2 days after a 245 mm precipitation event revealed the highest recorded 222 rn activities up to 86 1 dpm l 1 and high p co 2 up to 11 217 atm showing a strong groundwater influence after flooding these observations imply that groundwater discharge drove co 2 dynamics at the upstream station while multiple complex processes drove co 2 at the downstream station a 222 rn mass balance model demonstrated that groundwater discharge accounted for about 76 of surface water in this floodplain creek the co 2 evasion rates 799 225 mmol m 2 d 1 were driven primarily by currents rather than wind groundwater derived co 2 fluxes into the creek averaged 1622 mmol m 2 d 1 a value twice as high as atmospheric co 2 evasion and consistent with carbon uptake within the creek and downstream exports these results demonstrate that groundwater seepage was a major factor driving co 2 evasion to the atmosphere from the creek groundwater discharge should be accounted for in co 2 budgets in coastal systems

estimating drift velocity of polar cap patches with all sky airglow imager at resolute bay canada 1 highly sensitive all sky airglow imager has been operative at resolute bay canada 74 73 n 265 07 e aacgm latitude 82 9 since january 2005 we present as a first result from the imager an event of polar cap patches drifting anti sunward during the southward imf conditions magnitude and direction of patch drift velocities are computed with a temporal resolution of 2 min by using the newly developed patch tracking algorithm based on 2d cross correlation analysis it is well visualized that the patches change their moving speed and direction drastically in a short time scale a few minutes speed of the patch is primally controlled by the imf bz dawn dusk component of the patch drift velocities is well correlated with the imf by in agreement with published by dependence of the nightside polar cap convection however response of the patch drift direction to the imf by is found to be much slower 20 min than that of the drift speed to the imf bz almost instantaneous

intermediate scale plasma irregularities in the polar ionosphere inferred from gps radio occultation we report intermediate scale plasma irregularities in the polar ionosphere inferred from high resolution radio occultation ro measurements using gps global positioning system to cassiope cascade smallsat and ionospheric polar explorer satellite radio links the high inclination of cassiope and the high rate of signal reception by the gps attitude positioning and profiling ro receiver on cassiope enable a high resolution investigation of the dynamics of the polar ionosphere with unprecedented detail intermediate scale scintillation producing irregularities which correspond to 1 to 40 km scales were inferred by applying multiscale spectral analysis on the ro phase measurements using our multiscale spectral analysis approach and satellite data polar operational environmental satellites and defense meteorological satellite program we discovered that the irregularity scales and phase scintillations have distinct features in the auroral oval and polar cap we found that large length scales and more intense phase scintillations are prevalent in the auroral oval compared to the polar cap implying that the irregularity scales and phase scintillation characteristics are a function of the solar wind and magnetospheric forcings

paleosols as an indicator of climatic change at the early late cretaceous boundary southwestern new mexico abstract cretaceous aptian to lower campanian alluvial paleosols in southwestern new mexico suggest that a paleoclimatic change from arid or semi arid to humid or subhumid occurred near the boundary between early and late cretaceous lower cretaceous paleosols of the hell to finish lower aptian and mojado upper albian formations are primarily aridisols characterized by a dark reddish brown pedoturbated bw horizon underlain by a bk horizon composed of calcareous nodules and tubules or a massive calcareous bkm horizon retention of carbonate in the paleosol profiles suggests that annual precipitation was less than 60 cm in contrast upper cretaceous paleosols consist of non calcic alfisols and inceptisols inceptisols consist of two types 1 a gleyed variety displaying a bg and bc or cg horizons in the satten formation uppermost albian to lowermost cenomanian and in the crevasse canyon formation upper coniacian to lower campanian and 2 a non gleyed variety consisting of a bw and c horizons in the moreno hill and tres hermanos formations middle turonian and in the crevasse canyon formation in addition alfisols in the tres hermanos and crevasse canyon formations are composed of a e bt bc and c horizons the argillic b horizons bt contain kaolinite and mixed layer clay and display blocky peds vertical clay filled root traces and argillans indicative of relatively well drained woodland soils modern counterparts of the upper cretaceous alfisols exist in humid and subhumid regions receiving greater than 75 cm yr precipitation comparison of the data resented in this study with paleosol and paleobotanical data from other locations in the western interior of the u s suggests that the paleoclimatic change proposed for southwestern new mexico may have been of regional extent

use of radon 222 and calcium as tracers in a three end member mixing model for streamflow generation on the west fork of walker branch watershed genereux d p hemond h f and mulholland p j 1993 use of radon 222 and calcium as tracers in a three end member mixing model for streamflow generation on the west fork of walker branch watershed j hydrol 142 167 211 measurements of naturally occurring radon 222 222 rn and calcium ca in surface and subsurface waters on the west fork ef walker branch suggest that a simple three end member mixing model provides a realistic and useful framework for streamflow generation over a wide range of flow conditions the three end members are vadose zone water soil groundwater and bedrock groundwater bedrock groundwater was distinguished from the soil end members on the basis of its high ca content 222 rn concentration was the basis for the distinction between vadose zone water low 222 rn and soil groundwater high 222 rn the behavior of the end members with changing flow was consistent with a wide variety of environmental observations including temperature and flow variations at springs water table responses the general lack of saturated zones on hillslopes and even near the stream in some places and the importance of water movemen t through bedrock variability in the chemistry of the end members precluded using other solutes na k and so4 to test the mixing fractions derived from 222 rn and ca data during those times of year when the soil temperature is most different from that of the underlying bedrock late summer and late winter temperature may be a useful tracer for distinguishing between water from the soil end members and that from bedrock the mixing model provides a simple framework for analyzing the essential features of streamflow generation in this highly heterogeneous terrain

hydrological processes in the chalk unsaturated zone insights from an intensive field monitoring programme as part of the nerc lowland catchment research programme locar the pang lambourn catchments berkshire uk have been extensively instrumented to provide an improved understanding of the hydrological processes in the unsaturated zone of the chalk a subject of much debate over the past 30 years to quantify the movement of water through the unsaturated zone it is necessary to measure matric potential and water content as well as input and output fluxes from precipitation evapotranspiration and groundwater recharge previous studies have indicated the need for fine temporal resolution data to monitor this system effectively due to the challenges faced in meeting this objective a monitoring scheme was designed that combines a variety of instrumentation to provide the required range accuracy and spatial and temporal resolution of data this paper firstly presents an overview of the monitoring programme and a critical discussion of the instrumentation used subsequently the field data are used to characterise the hydrological properties of the unsaturated zone and to gain insight into recharge processes the interpretation of the data presented in this paper indicate that in the chalk unsaturated zone at west ilsley matrix flow is the dominant recharge mechanism

climatic and environmental indications of carbon and oxygen isotopes from the lower cretaceous calcrete and lacustrine carbonates in southeast and northwest china abstract carbon and oxygen isotopic ratios were determined from 100 lower cretaceous samples from four carbonate bearing facies in southeast se and northwest nw china for palaeoclimatic and palaeoenvironmental analyses the samples were interpreted as sediments within sublithofacies of distal alluvial ponds sf1 open shallow lakes sf2 littoral lakes sf3 and marshes sf4 results of analyses show in se china 13c values range between 5 0 and 3 0 with a negative trend through time and 18o values are all negative 19 3 7 4 in nw china 13c values range from 4 0 to 4 0 with periodic change and 18o values range between 18 0 and 1 5 both relatively heavy values and pronounced covariances of most 13c and 18o indicate semiarid climate and domination of closed brackish lakes marshes and ponds in nw and se china during the early cretaceous of them positive 13c 0 0 to 4 0 and relatively heavy 18o 5 0 to 1 5 values suggest interruptions of arid evaporation in intermittences of the early hauterivian in sw fujian of the middle aptian in west jiuquan basin of the late aptian in sw ordos basin and of the late aptian early albian in liupanshan basin in a short interval of the early aptian the hot and humid climate occurred in local sw zhejiang by high kaolinite content and in west jiuquan basin by warm flora could be an exception particularly extremely negative 18o values mainly 19 0 9 0 indicate relatively low temperature in se fujian in the berriasian barremian in liupanshan basin in the late aptian in sw ordos basin in the late albian and in west jiuquan basin in the mid late aptian which is supposed to attribute to the presence of 2500 m 4500 m in elevation more positive values and more covariance ratios of 13c and 18o in nw china than in se china and in mainland china than in america indicate a arider climate in former than in later probably attributing to the palaeogeography in distance to sea a tentative correlation of the early cretaceous 13c value excursion of calcretes shows a good compatibility between marine oaes and terrestrial carbonate sediments and between nw china and america continents implying a global response to carbon cycle in both marine and terrestrial environments the feature suggests the potential of global correlation and application of terrestrial calcrete 13c excursions in pre cenozoic