planetary surface dating from crater size frequency distribution measurements partial resurfacing events and statistical age uncertainty abstract we describe the procedure to fit a cumulative production function polynomial to a partial crater size frequency distribution the technique is of particular use in deriving ages for surfaces which have undergone partial resurfacing events namely erosional or depositional events which have affected a limited diameter range of the crater population we demonstrate its use in obtaining times for both the surface formation and the resurfacing event we give a practical outline of the method for making age measurements from crater counts and how to identify resurfacing effects in the results we discuss the conversion of production function polynomials between common presentations and the statistical uncertainty of the determined ages with respect to the non linear chronology function and a minor refinement of data binning

cassini imaging science initial results on phoebe and iapetus the cassini imaging science subsystem acquired high resolution imaging data on the outer saturnian moon phoebe during cassini s close flyby on 11 june 2004 and on iapetus during a flyby on 31 december 2004 phoebe has a heavily cratered and ancient surface shows evidence of ice near the surface has distinct layering of different materials and has a mean density that is indicative of an ice rock mixture iapetus s dark leading side cassini regio is ancient heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief local albedo variations within and bordering cassini regio suggest mass wasting of ballistically deposited material the origin of which remains unknown

application of multi isotope ratios to study the source and quality of urban groundwater in metro manila philippines abstract to characterize water quality in terms of dissolved elements and to investigate both the origin of the water and the source and behavior of groundwater contaminants in metro manila 33 water groundwater and surface water samples were analyzed for ion and element concentrations h and o isotope ratios d h2o and 18o h2o so 4 2 isotope ratios 34s so 4 2 and 18o so 4 2 and sr isotope ratio 87sr 86sr the chemical measurements showed that the primary important environmental concerns within metro manila are groundwater salinization for both shallow and deep aquifers and as concentrations up to 22 5 g l in shallow groundwaters comparison of so 4 2 and sr isotope values with possible source materials revealed that contamination by man made materials such as fertilizers and detergents are present in some shallow groundwaters shallow groundwater having higher d h2o and 18o h2o values av 44 5 6 and 6 8 0 6 respectively n 15 than deep groundwater av 48 4 4 and 7 4 0 7 respectively n 7 suggests that the origins of h2o in both groundwaters are different from each other since the mixing of shallow and deep groundwater does not commonly occur under metro manila the contaminants in the shallow aquifers are unlikely to be transported into the deep aquifers sulfate reduction by bacterial activity was observed for some groundwaters resulting in a maximum elevation in 34s so 4 2 values of around 10 by using so 4 2 isotope ratios as an indicator of changes in redox conditions and sr isotope ratio as a source indicator it was shown that as was dissolved from unconsolidated sedimentary deposits of volcanic origin which enclose shallow unconfined aquifers but was not the result of changes in redox conditions the study demonstrated that multi isotope ratios are useful for evaluating water quality problems in urban groundwaters

the ac 5 fejokoo quadrangle of ceres geologic map and geomorphological evidence for ground ice mediated surface processes abstract nasa s dawn spacecraft arrived at ceres on march 6 2015 and has been studying the dwarf planet through a series of successively lower orbits throughout these mission phases dawn obtained photographic mineralogical elemental abundance and gravity data ceres is the largest object in the asteroid belt with a mean diameter of 940 km the dawn science team conducted a geologic mapping campaign for ceres similar to the one that was implemented on the asteroid vesta dawn s previous target including production of a survey and high altitude mapping orbit hamo based global map and a series of 15 low altitude mapping orbit lamo based quadrangle maps in this paper we present the lamo based geologic map of the ac 5 fejokoo quadrangle 21 66 n and 270 360 e and discuss its implications the ac 5 quadrangle is primarily composed of ancient cratered terrain punctuated with several moderately fresh impact craters of geologic interest six large tholi that are possibly cryovolcanic in origin and an abundance of flows that well represent the full spectrum of mass wasting features observed on ceres the fejokoo quadrangle hosts the majority of oxo crater the site of the first spectroscopic detection of h2o ice on the surface of ceres the h2o detection is closely related to two distinctive morphological units interpreted as possible high water ice content landslides these observations and interpretations are consistent with ground ice mediated surface processes on ceres

isotopic trace element and nutrient characterization of coastal waters from ubatuba inner shelf area south eastern brazil abstract stable isotopes tritium radium isotopes radon trace elements and nutrients data were collected during two sampling campaigns in the ubatuba coastal area south eastern brazil with the aim of investigating submarine groundwater discharge sgd in the region the isotopic composition d 18o 3h of submarine waters was characterised by significant variability and heavy isotope enrichment the stable isotopes and tritium data showed good separation of groundwater and seawater groups the contribution of groundwater in submarine waters varied from a few to 17 spatial distribution of 222rn activity concentration in surface seawater revealed changes between 50 and 200 bq m 3 which were in opposite relationship with observed salinities time series measurements of 222rn activity concentration in flamengo bay from 1 to 5 kbq m 3 obtained by in situ underwater gamma spectrometry showed a negative correlation between the 222rn activity concentration and tide salinity this may be caused by sea level changes as tide effects induce variations of hydraulic gradients which increase 222rn concentration during lower sea level and opposite during high tides where the 222rn activity concentration is smaller the estimated sgd fluxes varied during 22 26 november between 8 and 40 cm d 1 with an average value of 21 cm d 1 the unit is cm3 cm2 per day the radium isotopes and nutrient data showed scattered distributions with offshore distance and salinity which implies that in a complex coast with many small bays and islands the area has been influenced by local currents and groundwater seawater mixing sgd in the ubatuba area is fed by coastal contaminated groundwater and re circulated seawater with small admixtures of groundwater which claims for potential environmental concern with implications on the management of freshwater resources in the region

in flight calibration of the dawn framing camera we present a method for calibrating images acquired by the dawn framing camera fc that is based on the results of an in flight calibration campaign performed during the cruise from earth to vesta we describe this campaign and the data analysis in full both the primary camera fc2 and the backup camera fc1 are radiometrically and geometrically calibrated through observations of standard stars star fields and solar system objects the calibration in each spectral filter is accurate to within a few percent for point sources geometric distortion small by design is characterized with high accuracy dark current monitored on a regular basis is very low at flight operational temperatures out of field stray light was characterized using the sun as a stray light source in field stray light is confirmed in narrow band filter images of vesta its magnitude and distribution are scene dependent and expected to contribute significantly to images of extended objects description of a method for in field stray light correction is deferred to a follow up paper as is a discussion of the closely related topic of flat fielding

fresh and saline groundwater discharge to the ocean a regional perspective 1 studies of groundwater flow in coastal aquifers often focus strongly on freshwater and investigate flow in a narrow 5 km zone surrounding the coastline this work was designed to place coastal flow in a regional context and to compare fresh and saline submarine groundwater discharge sgd for regional flow systems numerical flow and transport models were developed to estimate sgd associated with topography driven flow seawater recirculation and geothermal convection in a passive margin setting simulations were based on two cross sections of north carolina and sensitivity studies were used to explore the impact of varying hydraulic and transport parameters results suggest that saline flow associated with seawater recirculation and geothermal convection should be considered in studies of sgd studies limited to shallow topography driven flow may be justified in using small study areas but flow systems contributing to sgd may span at least 20 km surrounding the coast and continental slope

viscous flow rates of icy topography on the north polar layered deposits of mars we investigate the importance of viscous flow in shaping topography at the north polar layered deposits npld of mars by using finite element modeling to calculate the distribution of stresses and flow velocities present day impact craters on thenpldare too small and cold for viscous relaxation tohavebeen an important mechanism in controlling their current dimensions this effect may be ignored when analyzing crater size frequency distributions scarps at the npldmargins where avalanches of dust and carbon dioxide frost occur are sufficiently steep high andwarm to experience significant viscous flow we find flow velocities at the base of these steep scarps on the order of tens to hundreds of cm yr which are fast enough to significantly affect their slopeover kiloyear timescales alternatively the scarps could be close to steady state in which observed block falls provide a competing effect to viscous flow

spring sapping on the lower continental slope offshore new jersey undersea discharge of ground water during periods of lower sea level may have eroded valleys on part of the lower continental slope offshore new jersey steep headed basins cliffed and terraced walls and irregular courses of these valleys may have been produced by sapping of exposed near horizontal tertiary strata joints in eocene calcareous rocks would have localized ground water movement some karstlike features of the submarine topography and the outcrops suggest that solution of the calcareous rocks also took place

the avalanche lake rock avalanche mackenzie mountains northwest territories canada description dating and dynamics at avalanche lake located in the backbone ranges of the mackenzie mountains about 200 106 m3 of massive devonian carbonate rock slid down remarkably planar bedding surfaces dipping at 30 and c

composition and structure of the shallow subsurface of ceres revealed by crater morphology the dwarf planet ceres is thought to have an ice rich layer in its shallow subsurface the morphologies of craters however suggest little relaxation by viscous flow has occurred and instead indicate a subsurface that is less than 40 ice

age determination of linear surface features using the buffered crater counting approach case studies of the sirenum and fortuna fossae graben systems on mars buffered crater counting bcc offers a possibility to determine ages of linear curvilinear surface features that provide no or only very limited surface areas for the conventional crater counting approach in this study we applied the bcc analysis to two tectonic fault systems fortuna fossae and a subsection of sirenum fossae we compared bcc results with age estimates derived from conventional crater counting on the surrounding geologic units and investigated to what extent crater ejecta blankets can be used for determining the stratigraphic placement of craters pre or post dating the formation of linear features furthermore we introduce a new functionality of the cratertools software for arcgis which allows for a user friendly semi automatic application of the otherwise time consuming procedure of bcc analysis the software provides the resulting crater size frequency data in a standard format which can be read and analyzed in the craterstats analysis software our case studies showed that the bcc approach provides equivalent or even more precise age results compared to the conventional stratigraphic approach here we found that the investigated section of sirenum fossae is younger than previously thought the derived formation age from the bcc analysis is 3 44 0 25 0 1ga which corresponds to late instead of early hesperian fortuna fossae formed shortly after the emplacement of its now fractured geologic host unit late hesperian ages derived from bcc analysis vary between 3 53 0 11 0 06ga and 3 50 0 11 0 07ga furthermore we recommend the use of crater ejecta blankets to position them in the stratigraphic sequence in order to improve crater statistics however the accuracy of the results depends on the extent and preservation state of the continuous ejecta blankets in the region of interest thus the applied buffer width has to be chosen carefully according to investigated crater sizes and local observations

identification of sources and causes of leakage on a zoned earth dam in northern taiwan hydrological and isotopic evidence abstract seepage through an earth dam body must be regulated as a well planned process if it is not properly managed the abnormal seepage may cause dam failure this study employed stable isotopic and statistical methods to identify the source and cause of an abnormal leakage on the zoned earth dam of the xin shan reservoir located in northern taiwan water samples from the dam area over a 2 a period were collected and analyzed for their stable o and h isotope compositions in addition a 4 a period of hydrological data including rainfall reservoir level well level seepage of filter drainage and leakage were statistically analyzed with a stepwise multiple regression approach both the stable isotopic and hydrological results indicate that the abnormal leakage on the dam shell comes from the filter drainage in the dam the reason for abnormal leakage is due to unexpected and significant precipitation sourced water flowing into the dam s body the dam filter fails to drain out the incoming water sufficiently thus generating the abnormal seepage in addition the defect in the dam filter may also cause the drainage filter to drain off reservoir seepage inadequately therefore it is suggested that checking the filter function and preventing excessive precipitation sourced water from flowing into the dam are the two top priorities for the follow up remedial strategy of the dam

introduction the geologic mapping of vesta the purpose of this paper is to introduce the geologic mapping of vesta special issue section of icarus which includes several papers containing geologic maps of the surface of vesta made to support data analysis conducted by the dawn science team during the vesta encounter july 2011 september 2012 in this paper we briefly discuss pre dawn knowledge of vesta provide the goals of our geologic mapping campaign discuss the methodologies and materials used for geologic mapping review the global geologic context of vesta discuss the challenges of mapping the geology of vesta as a small airless body and describe the content of the papers in this special issue section we conclude with a discussion of lessons learned from our quadrangle based mapping effort and provide recommendations for conducting mapping campaigns as part of planetary spacecraft nominal missions

transformation of dilative and contractive landslide debris into debris flows an example from marin county california abstract the severe rainstorm of january 3 4 and 5 1982 in the san francisco bay area california produced numerous landslides many of which transformed into damaging debris flows the process of transformation was studied in detail at one site where only part of a landslide mobilized into several episodes of debris flow the focus of our investigation was to learn whether the landslide debris dilated or contracted during the transformation from slide to flow the landslide debris consisted of sandy colluvium that was separable into three soil horizons that occupied the axis of a small topographic swale failure involved the entire thickness of colluvium however over parts of the landslide the soil a horizon failed separately from the remainder of the colluvium undisturbed samples were taken for density measurements from outside the landslide from the failure zone and overlying material from the part of the landslide that did not mobilize into debris flows and from the debris flow deposits the soil a horizon was contractive and mobilized to flows in a process analogous to liquefaction of loose granular soils during earthquakes the soil b and c horizons were dilative and underwent 2 to 5 volumetric expansion during landslide movement that permitted mobilization of debris flow episodes several criteria can be used in the field to differentiate between contractive and dilative behavior including lag time between landsliding and mobilization of flow episodic mobilization of flows and partial or complete transformation of the landslide

in situ creep properties in ice rich permafrost soil an in situ analysis of naturally occurring creep has been carried out at the proposed canadian arctic gas pipeline crossing of great bear river in the northwest territories this is the third of fo

periodical changes of submarine fluid discharge from a deep seafloor suiyo sea mountain japan 1 semi diurnal variations of the fluid discharge from the deep sea bottom were found at the water depth of 1360 m suiyo sea mountain ogasawara japan by using newly developed automated seepage meters a temperature depth profile of the pore water under the seabed also suggests heat is transported due to advection by the upward fluid flow upward fluid fluxes estimated from the type curve method using heat conduction convection theory agreed well with the values obtained by automated seepage meter

partition of suspended and riverbed sediments related to the salt wedge in the lower reaches of a small mountainous river a month long comprehensive field experiment during the beginning of the flood season of a small mountainous river in southern taiwan was carried out in 2004 the major goal of the study was to investigate the effect of hydrodynamic sorting related to the salt water intrusion on the spatial variability of suspended and riverbed sediments and their coupling of different sizes the experiment included the deployment of an instrumented tetrapod near the river mouth with an upward looking adcp and two ctds mounted at 50 and 100 cm above the bed cmab respectively on three different days along the river turbidity salinity and temperature of the water column were profiled and water samples were taken from the surface and near the bed at different stations additionally one sediment sample was also taken from the riverbed suspended sediment concentrations ssc were analyzed for five different sizes i e 500 250 500 63 250 10 63 and 1 2 10 m by filtration for each riverbed sample the size composition was analyzed for the subsample that contained lithogenic and nonlithogenic components and the subsample having major nonlithogenic components organic matter carbonates and biogenic opal was removed the grain size frequency distributions of the riverbed samples were analyzed using a laser particle analyzer the results were grouped into the following size classes 473 249 473 62 249 10 62 and 10 m for comparison with those of the suspended sediments near the riverbed some suspended sediment samples were analyzed for poc and pon some riverbed samples were analyzed for toc statistical methods of linear regression and empirical orthogonal eigen function eof were used in the data analysis two layered estuarine circulation pattern was observed at the tetrapod site the tidally driven salt water intrusion is the major factor influencing the hydrodynamics of the gaoping river which in turn affect the longitudinal and vertical distribution of the suspended sediments and the longitudinal distribution of the riverbed sediments during the flood the intrusion front of the salt wedge creates a dynamic barrier upriver from this barrier the riverbed substrate is coarser composed of sediments mostly coarser than 249 m within the salt wedge the riverbed substrate is finer consisting of mostly mud 62 m the barrier creates a trap on the riverbed immediately seaward from the intrusion front retaining higher percentages of clay sized sediments and toc the barrier also creates partition in the terrestrial and marine sources of organic matter in the suspended and riverbed sediments within the salt wedge the major contributor of riverbed toc is the clay sized marine sediment transport upriver by the intruding seawater the terrestrial poc is a minor contributor to the riverbed toc the riverbed and suspended sediments are coupled most size classes in corresponding suspended and riverbed sediments have a reciprocal relationship negative feedback through resuspension and deposition on the water bed interface the only size class of 62 473 m on the riverbed and 63 250 m in the suspension are co varying positive feedback this size class contains largely a transient floc population that is formed and disintegrated in situ both on the riverbed and in the suspension in the course of a tidal cycle

stable isotope studies of precipitation and river water in the lake biwa basin japan the 18o and d in 17 river waters flowing into and out of lake biwa the lake water itself and precipitation at 11 locations in the lake biwa basin were observed from october 1996 to september 1997 to evaluate the origin of river waters and the effect of irrigation water from the lake on the river waters flowing into lake biwa the regional difference and altitude effect of the stable isotopes in precipitation and river water were found in the basin the 18o in the rivers which are located in the eastern and the southern areas in the basin is heavier than that of the other rivers due to the effect of irrigation for the nearby paddy fields evaporation from lake biwa and the inflow rate into the lake estimated from the 18o balance agree well with the results of previous studies which used water balance methods the stable isotopes can enable us to evaluate not only water balance but also the origin of the water and the water flow system copyright 2000 john wiley sons ltd

the geomorphology of ceres introduction observations of ceres the largest object in the asteroid belt have suggested that the dwarf planet is a geologically differentiated body with a silicate core and an ice rich mantle data acquired by the dawn spacecraft were used to perform a three dimensional characterization of the surface to determine if the geomorphology of ceres is consistent with the models of an icy interior rationale instruments on dawn have collected data at a variety of resolutions including both clear filter and color images digital terrain models have been derived from stereo images a preliminary 1 10 m scale geologic map of ceres was constructed using images obtained during the approach and survey orbital phases of the mission we used the map along with higher resolution imagery to assess the geology of ceres at the global scale to identify geomorphic and structural features and to determine the geologic processes that have affected ceres globally results impact craters are the most prevalent geomorphic feature on ceres and several of the craters have fractured floors geomorphic analysis of the fracture patterns shows that they are similar to lunar floor fractured craters ffcs and an analysis of the depth to diameter ratios shows that they are anomalously shallow compared with average ceres craters both of these factors are consistent with ffc floors being uplifted due to an intrusion of cryomagma kilometer scale linear structures cross much of ceres some of these structures are oriented radially to large craters and most likely formed due to impact processes however a set of linear structures present only on a topographically high region do not have any obvious relationship to impact craters geomorphic analysis suggests that they represent subsurface faults and might have formed due to crustal uplift by cryomagmatic intrusion domes identified across the ceres surface present a wide range of sizes 100 km basal shapes and profiles whether a single formation mechanism is responsible for their formation is still an open question cryovolcanic extrusion is one plausible process for the larger domes although most small mounds 10 km diameter are more likely to be impact debris differences in lobate flow morphology suggest that multiple emplacement processes have operated on ceres where three types of flows have been identified type 1 flows are morphologically similar to ice cored flows on earth and mars type 2 flows are comparable to long runout landslides type 3 flows morphologically resemble the fluidized ejecta blankets of rampart craters which are hypothesized to form by impact into ice rich ground conclusion the global trend of lobate flows suggests that differences in their geomorphology could be explained by variations in ice content and temperature at the near surface geomorphic and topographic analyses of the ffcs suggest that cryomagmatism is active on ceres whereas the large domes are possibly formed by extrusions of cryolava although spectroscopic analysis to date has identified water ice in only one location on ceres the identification of these potentially ice related features suggests that there may be more ice within localized regions of ceres crust figure 1 dawn high altitude mapping orbit imagery 140 meters per pixel of example morphologic features a occator crater arrows point to floor fractures b linear structures denoted by arrows c a large dome at 42 n 10 e visible in the elevation map d a small mound at 45 5 s 295 7 e e type 1 lobate flow arrows point to the flow front analysis of dawn spacecraft framing camera image data allows evaluation of the topography and geomorphology of features on the surface of ceres the dwarf planet is dominated by numerous craters but other features are also common linear structures include both those associated with impact craters and those that do not appear to have any correlation to an impact event abundant lobate flows are identified and numerous domical features are found at a range of scales features suggestive of near surface ice cryomagmatism and cryovolcanism have been identified although spectroscopic analysis has currently detected surface water ice at only one location on ceres the identification of these potentially ice related features suggests that there may be at least some ice in localized regions in the crust 1 pending yes

long runout landslides and the long lasting effects of early water activity on mars reply long runout subaerial landslides 50 km are rare on earth but are common features shaping mars valles marineris troughs in this study we investigated the highly debated emplacement mechanisms of these martian landslides by combining spectral and satellite image analyses our results suggest that hydrated silicates played a decisive role in facilitating landslide transport by lubricating the basal sliding zone this new understanding implies that clay minerals generated as a result of water rock interactions in the noachian and hesperian 4 1 3 3 ga exert a long lasting influence on geomorphic processes that shape the surface of the planet

a carbon isotope method to quantify groundwater discharge at the land sea interface we present a new method to characterize and quantify groundwater discharge to estuaries and the coastal ocean using data from the pages creek estuary in the cape fear region of southeastern north carolina we show that the concentration and carbon isotopic composition d 14 c and d 13 c values of dissolved inorganic carbon dic can provide a tracer of a single well defined component of the surface water groundwater system in coastal regions the integrated freshwater discharge to an estuary from confined aquifers groundwater from the two shallowest confined aquifers in the cape fear region the castle hayne and the peedee has dic d 14 c values ranging from 2282 to 2829 significantly lower than the radiocarbon content of surficial water table groundwater rivers and streams and seawater in the area d 14 c 52 38 to 197 dic additions from salt marsh decomposition and dic removal via photosynthesis and gas evasion can influence estuarine dic concentrations and dic d 13 c values however none of these processes results in strongly depleted dic d 14 c values because artesian springs are the only significant low d 14 c dic input to the pages creek estuary flood ebb 14 c budgets provide a direct measure of the fraction of the total freshwater inputs to the pages creek estuary that is derived from artesian discharge with this method we have observed a striking range in the relative contribution of artesian flow to the pages creek estuary freshwater budget during november 1999 and april 2001 both periods of low precipitation in southeastern north carolina artesian groundwater discharge could account for essentially all of the pages creek freshwater inputs in contrast during july 2000 a period of high precipitation in this region artesian groundwater made a negligible contribution to the creek s freshwater budget

using hydrogen oxygen and tritium isotopes to identify the hydrological factors contributing to landslides in a mountainous area central taiwan over a 1 year period 343 samples including precipitation creek pond and groundwater were collected from june 2003 to may 2004 analyses were performed for stable oxygen and hydrogen isotope compositions selected samples were also analyzed for tritium the goal was to identify possible hydrologic factors contributing to a severe landslide in the li shan area central taiwan the isotope characteristics indicate that groundwater from fu shou shan farm located up slope from the landslide area is a major source for slope groundwater in addition to precipitation the groundwater is mainly recharged by pond water at fu shou shan farm according to the calculation of a two end member equation with 18o the contribution of farm groundwater to slope groundwater is significantly higher than that of precipitation up to a factor of five the estimated drainage efficiency of the existing system is only 23 draining off the slope groundwater in the up slope region to decrease farm groundwater flow into the slope area is a feasible strategy to effectively reduce the risk of landslide

groundwater seawater interactions off the coast of southern taiwan evidence from environmental isotopes abstract we have conducted detailed hydrochemical surveys off the pingtung plain coast sw taiwan using environmental isotope compositions d 18 o 13 c dic tritium and 14 c as the main tracers to investigate groundwater seawater interactions in the region the 18 o values of seawater in this area show significant variability with heavy isotope enrichment relatively to groundwater the d and 18 o data also confirmed that submarine groundwater discharge sgd originated from meteoric water and were mixed with seawater due to an overdraft of groundwater seawater has intruded inwardly through the offshore outcrops for both the unconfined and confined aquifers at a depth of 300 m however 18 o depleted layer is found along deep parts of kaoping canyon this result provides evidence for sgd in this region this phenomenon is also reflected in depleted 13 c dic and lower 14 c values in deep canyon water than in adjacent seawater and indicating that the discharge zone extends over a considerable distance to the offshore area 25 km based on these three parameters 18 o 13 c dic and 14 c we used two end member mixing model to estimate that fresh submarine groundwater constitute the submarine fresh groundwater contributed about 3 and the estimated submarine fresh groundwater discharge was calculated as 4 5 10 9 m 3 per year this result is comparable with groundwater annual loss in the pingtung plain as documented by the isotopic composition of the collected samples detailed results show that sgd in the pingtung coastal zone raises a potential environmental concern and provides implication for the management of groundwater resource in the region

thermal stability of ice on ceres with rough topography the dwarf planet ceres may have an ice rich crust and subsurface ice exposed by impacts or endogenic activity would be subject to sublimation we model surface and subsurface temperatures on ceres to assess lifetimes of water ice and other volatiles topographic shadowing allows a small but non negligible fraction 0 4 of ceres surface to be perennially below the 110 k criterion for 1 gyr of stability these areas are found above 60 latitude other molecules ch3oh nh3 so2 co2 may be cold trapped in smaller abundances a model for the transport gravitational escape and photoionization of h2o molecules suggests net accumulation in the cold traps buried ice is stable within a meter for 1 gyr at latitudes higher than 50 an illuminated polar cap of water ice would be stable within a few degrees of the poles only if it maintained a high albedo 0 5 at present obliquity if the obliquity exceeded 5 in the geologically recent past then a putative polar cap would have been erased at latitudes 0 30 ice is stable under solar illumination only briefly 10 100 yr unless it has high albedo and thermal inertia in which case lifetimes of 104 yr are possible finally a small hemispheric asymmetry exists due to the timing of ceres perihelion passage which would lead to a detectable enhancement of ice in the northern hemisphere if the orbital elements vary slowly relative to the ice accumulation rate our model results are potentially testable during the dawn science mission

environmental isotopes to test hypotheses for fluid mud mud bank generation mechanisms along the southwest coast of india abstract occurrence of fluid mud mud banks in the southwest coast of india is an enigma for the scientific community over the years several multi disciplinary studies were conducted and various hypotheses were postulated on the occurrence and sustenance of fluid mud nevertheless none of them could be proved or disproved with field data in the present study an attempt was made to assess the validity of some of the prevailing hypothesis on its occurrence such as subterranean conduit flow of mud water from a coastal lagoon submarine groundwater discharge river flows etc by integrating field surveys refining the hydrogeological understanding of the area and application of environmental isotopes 222 rn 18 o 2 h and 3 h in the alappuzha mud bank region kerala during its formation in the southwest monsoon period in situ 222 rn monitoring survey in the coastal waters of pallana showed that 222 rn activities in the fluid mud region were negligible compared to the suspected continental end members such as pamba river vembanad lagoon shallow and deep groundwater indicating that there was no freshwater inputs from these sources comparison of the characteristic stable isotopic signatures of 18 o and 2 h in the samples from the fluid mud region and the suspected continental end members implied that there was no mixing of these water sources with the seawater 3 h results indicated that the shallow groundwater is modern and recharged annually from precipitation while deep groundwater in the warkali aquifer within the study area is old 50 years it also indicated that there is no vertical interconnection between the vembanad lagoon and the deep warkali aquifers hence from the study it appears that river flows submarine groundwater discharge or subterranean conduit flow flow from the vembanad lagoon may not be responsible for the occurrence and sustenance of fluid mud in pallana coast alappuzha

localized sources of water vapour on the dwarf planet 1 ceres the largest asteroid of the solar system 1 ceres has been thought to have an icy surface here it is observed to be emitting water vapour the presence of hydrated minerals on the surface of ceres the largest body in the solar system s main asteroid belt suggested that there may be water there too now infrared spectra obtained by esa s herschel space observatory provide unambiguous evidence that there is water ice at or near the surface of ceres water vapour is issuing at a rate of at least 1026 molecules per second from sources on ceres localized to mid latitude regions the water evaporation could be due to comet like sublimation or to cryo volcanism in which volcanoes erupt volatiles such as water instead of molten rocks this finding supports models that propose that the icy bodies such as comets may have migrated into the asteroid belt from beyond the notional snowline dividing the early solar system into a dry inner and icy outer regions the snowline conventionally divides solar system objects into dry bodies ranging out to the main asteroid belt and icy bodies beyond the belt models suggest that some of the icy bodies may have migrated into the asteroid belt1 recent observations indicate the presence of water ice on the surface of some asteroids2 3 4 with sublimation5 a potential reason for the dust activity observed on others hydrated minerals have been found6 7 8 on the surface of the largest object in the asteroid belt the dwarf planet 1 ceres which is thought to be differentiated into a silicate core with an icy mantle9 10 11 the presence of water vapour around ceres was suggested by a marginal detection of the photodissociation product of water hydroxyl ref 12 but could not be confirmed by later more sensitive observations13 here we report the detection of water vapour around ceres with at least 1026 molecules being produced per second originating from localized sources that seem to be linked to mid latitude regions on the surface14 15 the water evaporation could be due to comet like sublimation or to cryo volcanism in which volcanoes erupt volatiles such as water instead of molten rocks

northern mid latitude glaciation in the late amazonian period of mars criteria for the recognition of debris covered glacier and valley glacier landsystem deposits lobate debris aprons lda and lineated valley fill lvf have been known to characterize the mid latitude regions of mars since documented by viking their flow like character suggested that deposition of ice in talus pile pore space caused lubrication and flow during an earlier climatic regime a number of factors have remained uncertain however including the detailed structure and texture of lda lvf the relationships between them their direction of flow the origin and abundance of the lubricating agent and their exact mode of origin e g ice assisted rock creep ice rich landslides rock glaciers debris covered glaciers we use new high resolution stereo camera hrsc image and topography data in conjunction with a range of other post viking data sets and new insights provided by cold based terrestrial glacial analogs to assess the characteristics of lda lvf in the northern mid latitudes of mars we find evidence that the characteristics and flow patterns of the lda and lvf are most consistent with late amazonian debris covered glacial valley landsystems the broad distribution and integrated characteristics of the lda lvf systems suggest that earlier in the amazonian climatic conditions were such that significant snow and ice accumulated on mid latitude plateaus and in valleys producing integrated glacial landsystems the remnants of which are preserved today beneath residual sublimation till derived from adjacent valley walls atmospheric general circulation models suggest that these climatic conditions occurred when mars was at a spin axis obliquity of 35 and the atmosphere was relatively dusty glacial flow modeling under these conditions produces patterns similar to those documented in the lda lvf and sharad radar data suggests that significant amounts of ice remain sequestered below the sublimation lag today

large submarine groundwater discharge sgd from a volcanic island 1 we measured seepage rates of coastal groundwater from a volcanic island standing in the south sea of korea the seepage rates measured along the sandy coast were in the range 50 300 m yr which are much higher than those reported from typical continental coast the 18o tracer in potential seeping waters signifies that they are mixtures of basal groundwater and pristine seawaters on the eastern coast of jeju almost all groundwater discharge is attributed to recirculating seawater while fresh groundwater contributes about 20 of the total submarine groundwater discharge sgd on the western coast of jeju thus sgd appears to be important for the management of water resources in western jeju the measured radionuclides 228ra 226ra and 222rn and nutrients in the groundwater suggest that the discharge of both fresh and recirculated seawater will have a significant influence on the budget of coastal nutrients and other chemical constituents in this region

in flight calibration of the dawn framing camera ii flat fields and stray light correction abstract the nasa dawn spacecraft acquired thousands of images of asteroid vesta during its year long orbital tour and is now on its way to asteroid ceres a method for calibrating images acquired by the onboard framing camera was described by schroder et al schroder et al 2013 icarus 226 1304 however their method is only valid for point sources in this paper we extend the calibration to images of extended sources like vesta for this we devise a first order correction for in field stray light which is known to plague images taken through the narrow band filters and revise the flat fields that were acquired in an integrating sphere before launch we used calibrated images of the vesta surface to construct simple photometric models for all filters that allow us to study how the spectrum changes with increasing phase angle phase reddening in combination with these models our calibration method can be used to create near seamless mosaics that are radiometrically accurate to a few percent such mosaics are provided in jvesta the vesta version of the jmars geographic information system

mass movement on vesta at steep scarps and crater rims the quadrangles av 11 and av 12 on vesta are located at the northern rim of the giant rheasilvia south polar impact basin the primary geologic units in av 11 and av 12 include material from the rheasilvia impact basin formation smooth material and different types of impact crater structures such as bimodal craters dark and bright crater ray material and dark ejecta material av 11 and av 12 exhibit almost the full range of mass wasting features observed on vesta such as slump blocks spur and gully morphologies and landslides within craters processes of collapse slope instability and seismically triggered events force material to slump down crater walls or scarps and produce landslides or rotational slump blocks the spur and gully morphology that is known to form on mars is also observed on vesta however on vesta this morphology formed under dry conditions

ceres evolution and current state 1 we modeled several thermal evolution scenarios for ceres to explore the nature of large wet protoplanets and to predict current day evidence that might be found by close inspection such as by the dawn mission the density for ceres is near 2 1 suggesting a water content between 17 and 27 by mass short and long lived radioactive nuclide heating is considered even if only long lived radionuclide heating is assumed the water ice in ceres melts quickly and a water mantle forms but an approximately 10 km crust does not melt the circulating warm water would alter the silicates as heat is lost by conduction through the frozen crust water begins to freeze out at the base of the crust solid state convection begins and transports more heat as well as perhaps material dissolved or entrained in the water to or near the surface ceres water layer eventually but perhaps not entirely freezes forming a layered density structure with perhaps some liquid water remaining today our differentiated models are in agreement with the recently measured difference between the equatorial and polar radii we find that ceres existence and evolution depend critically on it containing water at formation and this depends strongly on the combination of when it accreted and the amount of 26al present in the pre ceres 1 km sized objects slightly more 26al or earlier accretion produces a dry vesta like object melting and freezing plus mineralization would lead to several dimensional changes over time creating topographic features zones of weakness and perhaps disruptions in the crust

glaciation in the andes during the lateglacial and holocene this review updates the chronology of andean glaciation during the lateglacial and the holocene from the numerous articles and reviews published over the past three decades the andes which include some of the world s wettest and driest mountainous regions offer an unparalleled opportunity to elucidate spatial and temporal patterns of glaciation along a continuous 68 degree meridional transect the geographic and altitudinal extent of modern glaciers and the sensitivity of both modern and former glaciers to respond to changes in specific climatic variables reflect broad scale atmospheric circulation and consequent regional moisture patterns glaciers in the tropical andes and in the mid latitude andes are likely to have been far more sensitive to changes in temperature than glaciers in the dry subtropical andes broad scale temporal and spatial patterns of glaciation during the lateglacial are apparent in the southernmost andes the lateglacial chronology appears to have a strong antarctic signature with the best dated moraines correlating closely with the antarctic cold reversal the southernmost andes do not appear to have experienced a significant ice advance coeval with the younger dryas yd climatic reversal at the other end of the andes from w 0t o 9 n a stronger yd connection may exist but critical stratigraphic and geochronologic work is required before a yd ice advance can be fully demonstrated in the central andes of peru well dated moraines record a significant ice readvance at the onset of the yd but ice was retreating during much of the remaining yd interval the spatial temporal pattern of holocene glaciation exhibits tantalizing but incomplete evidence for an early to mid holocene ice advance s in many regions but not in the arid subtropical andes where moraines deposited during or slightly prior to the little ice age lia record the most extensive advance of the holocene in many regions there is strong evidence for neoglacial advances in the interval between 1 0 and 2 5 ka moraines that correlate with the lia of the northern hemisphere are seen in all presently glacierized mountain ranges most of these date to within the past 450 years outboard of these moraines in many regions are moraines of a slightly more extensive advance that occurred several hundred years prior to the onset of the lia priorities for future work include filling in several prominent spatial gaps in the distribution of chronologic studies for the lateglacial these gaps include the arid regions of northern chile and argentina the southern peruvian andes between 11 5 and 13 5 s and the andes of northern peru and

18o and 226ra in the minjiang river estuary china and their hydrological implications abstract in this work the 2h 18o and 226ra values in groundwater and surface water in the minjiang river estuary were investigated in the dry and wet seasons the 18o values in the dry season were always higher than those in the wet season in both groundwater and surface water because of the presence of evaporation in the water cycle process during the dry season the 18o values in groundwater on the southern bank of the minjiang river are much higher than those on the northern bank because evaporation is more intense in the farmland of the southern bank than in the urbanized northern bank the 18o values in the estuarine water exhibit a good positive correlation with salinity with a coefficient of 0 96 p 0 05 in both seasons the 226ra activities in the estuarine water increase with increasing salinity because of desorption from riverine suspended particles the 226ra activity reaches a peak value at a salinity of 20 5 based on a three endmember model the average proportions of the estuarine water are calculated to be 0 02 for groundwater 0 39 for river water and 0 59 for seawater from this mixing ratio the groundwater discharge into the estuary is estimated to be 9 31 106 m3 d 1 in the wet season

the intrusion of water masses into the sea southwest of taiwan characteristics of water masses were analyzed to study the kuroshio intrusion into the sea southwest of taiwan hydrographic data were obtained from ctd conductivity temperature and depth casts during two cruises in may and august 1986 in may remnants of water intruding from the kuroshio were found on the continental slope south of the penghu channel by august these were replaced by water from the south china sea during this period water from the kuroshio also appeared near the southern tip of taiwan the intrusion current reached a depth of at least 500 m and was probably part of a cyclonic circulation in the northern south china sea the results support the hypothesis of a seasonal pattern of the intrusion process intrusion of water from the kuroshio begins in late summer intensifies in winter and ceases by late spring when south china sea waters again enter this region

crater formation and modification on the icy satellites of uranus and saturn depth diameter and central peak occurrence depth diameters d d for fresh craters on the intermediate sized icy satellites of uranus and saturn have been determined using photoclinometry and shadow lengths and are compared with similar measurements on the terrestrial planets simple bowl shaped craters on icy satellites including those on miranda for which the highest resolution data are available are systematically 20 40 shallower than on the terrestrial planets this pronounced difference between crater depths on icy and rocky surfaces indicates that differences in impact velocity or surface gravity are not as important as the differences in mechanical properties between ice and rock in controlling simple crater morphology experimental impact studies indicate that differences in material properties such as angle of internal friction can control crater depth alternatively breccia lenses may be thicker in icy satellite simple craters complex craters on the icy satellites become significantly deeper with increasing crater diameters unlike complex craters on terrestrial planets which are nearly constant in depth central peaks and hence floor rebound are also volumetrically and morphologically more prominent than wall slumping rim collapse on the icy satellites the magnitude of viscous relaxation of very large craters e g herschel and odysseus on the icy satellites can be estimated from extrapolation of the d d fits at smaller crater diameters the transition diameter from simple to complex morphology is inversely correlated with gravity as it is on the terrestrial planets but at significantly smaller diameters than would be expected from a simple extrapolation of the terrestrial trend thus crater modification especially floor rebound is easier to initiate on icy satellites estimated effective cohesions for shocked icy material are lower by a factor of 10 20 relative to rock although estimated effective viscosities are similar the distinct systematic differences between crater morphology on icy and rocky worlds indicate that gross material property differences between rock and ices play a key role in crater formation and modification but gravity is still the primary driving force

neotectonic architecture of taiwan and its implications for future large earthquakes the disastrous effects of the 1999 chi chi earthquake in taiwan demonstrated an urgent need for better knowledge of the island s potential earthquake sources toward this end we have prepared a neotectonic map of taiwan the map and related cross sections are based upon structural and geomorphic expression of active faults and folds both in the field and on shaded relief maps prepared from a 40 m resolution digital elevation model augmented by geodetic and seismologic data the active tandem suturing and tandem disengagement of a volcanic arc and a continental sliver to and from the eurasian continental margin have created two neotectonic belts in taiwan in the southern part of the orogen both belts are in the final stage of consuming oceanic crust collision and suturing occur in the middle part of both belts and postcollisional collapse and extension dominate the island s northern and northeastern flanks both belts consist of several distinct neotectonic domains seven domains kaoping chiayi taichung miaoli hsinchu ilan and taipei constitute the western belt and four domains lutao lanyu taitung hualien and ryukyu make up the eastern belt each domain is defined by a distinct suite of active structures for example the chelungpu fault source of the 1999 earthquake and its western neighbor the changhua fault are the principal components of the taichung domain whereas both its neighboring domains the chiayi and miaoli domains are dominated by major blind faults in most of the domains the size of the principal active fault is large enough to produce future earthquakes with magnitudes in the mid 7 values