stratigraphic architecture and infill history of a deglaciated bedrock valley based on georadar seismic profiling and drilling the sediment fill of a silled bedrock valley in western norway has been investigated with respect to stratigraphy and infill history using a combination of mapping georadar seismic profiling and drilling a small outlet glacier occupies the head of the valley that displays a stepwise down valley profile and terminates in a lake at 29 m above sea level the valley is surrounded by high steep bedrock slopes and is characterized by a series of filled basins each limited by sills of bedrock or moraine accumulations till glacial outwash and or rockslide deposits fill in the lower half of the two larger basins fan delta deposits fringed by the deposits of alluvial fans and colluvial cones dominate the upper fill of most basins fan delta deposits interfinger downstream with lake sediments in the larger basins and fluvial deposits comprise the top fill the overall infill pattern was controlled by deglaciation as well as basin size and shape an overall decreasing sediment supply following deglaciation is shown in the fill of a larger basin down valley whereas a recently increasing sediment supply during glacier growth is reflected primarily in an upstream basin only the lowermost basin was exposed to a sea level drop from 75 m above sea level to the present lake level associated with incision and river migration this observation is in contrast to the basins above marine influence where incision has been limited due to fixed downstream sills resulting in insignificant erosion except for some fan head entrenchment it follows that the fills of these small valley basins display progradational and aggradational trends of deposition and paraglacial reworking has been limited additionally the study demonstrates that georadar profiling combined with other methods is very useful for comprehensive investigation of valley basins

late glacial cirque glaciation in parts of western norway younger dryas cirque glaciers are known to have existed beyond the scandinavian ice sheet in parts of western norway at krakenes on the outermost coast a cirque glacier formed and subsequently wasted away during the younger dryas no glacier existed there during the allerod large cirque moraines some with marine deltas and associated fans extend into the western part of sykkylvsfjorden comparison with existing late glacial sea level curves shows that the uppermost marine sediment in these features was deposited well above younger dryas sea level demonstrating that the cirques were occupied by glaciers before the younger dryas during the younger dryas the cirque glaciers expanded and some advanced across the deltas depositing till and supplying the sediment to form lower level fans and deltas controlled by younger dryas sea level the extent of the younger dryas advance of some of the glaciers was at least in part controlled by grounding on material deposited before the younger dryas the depositional history of the glacial marine deposits in the sykkylven area indicates that cirque glaciers existed throughout late glacial time and only expanded during the younger dryas the sediment sequence in glacial lakes beyond cirque moraines and reconstructions of glacier equilibrium lines indicate that this was true for most cirques in western norway only on the outermost coast were new glaciers formed in response to younger dryas climate cooling 1998 john wiley sons ltd

glacial remobilization cycles as revealed by lateral moraine sediment bodalsbreen glacier foreland western norway the proglacial area of bodalsbreen glacier in western norway contains nine moraine ridges formed at the maximum of the little ice age ad 1755 and during the subsequent glacier retreat ad 1767 2000 the frontal moraines are composed of a sandy diamicton whereas the lateral ones consist of only boulder sized clasts without any matrix these lateral moraines seemingly are composed of a very high proportion of mature clasts a notion supported by detailed clast roundness and shape analyses furthermore there is evidence for a decline in clast maturity between the outer older three and the inner younger three moraine ridges this decline is interpreted as a change from recycled to freshly plucked clasts thus the more mature clasts in the outer moraines are thought to consist of sediment that has been recycled in the glacial system whereas the less mature clasts on the inner moraine ridges comprise younger glacially freshly plucked material the holocene glacial history of the study area with a

injection induced fracturing process in a tight sandstone under different saturation conditions to investigate the influence of local hydraulic condition on the water injection induced fracture behavior in tight sandstone injection tests under triaxial compression were conducted on samples collected from the sichuan basin china by means of acoustic emission ae monitoring the fracturing behaviors of two samples of different water saturation patterns partly saturated the middle part was dry and fully saturated are investigated experiment results indicate that the local hydraulic condition plays a governing role in the mechanical properties ae productivity fracture nucleation and the geometry of the shear fracture zone during axial loading stage the partly saturated sample demonstrated 35 higher elastic modulus than the fully saturated sample during the injection induced fracturing stage progressively increasing ae activity and dilatancy with increasing injected water volume were observed preceding the dynamic fracture in the partly saturated sample demonstrating a positive feedback between damage growing and fluid flow more aes were located in the dry or partially saturated regions at water front and thus produced dilatancy however the fully saturated sample shows very low ae activity 5 of that in partly saturated sample which was initiated immediately before the dynamic fracture phase due to the very low permeability 0 001 md volume of water injected into the fully saturated sample during the loading and creep stages is very limited indicating the observed large dilatancy is governed by pore pressure increasing due to stress compaction ae hypocenters demonstrated that an irregular shear fracture zone was created in the partly saturated sample while a relatively flat shear plane was formed in the fully saturated sample

features of co2 fracturing deduced from acoustic emission and microscopy in laboratory experiments we conducted hydraulic fracturing hf experiments on 170 mm cubic granite specimens with a 20 mm diameter central hole to investigate how fluid viscosity affects hf process and crack properties in experiments using supercritical carbon dioxide sc co2 liquid carbon dioxide l co2 water and viscous oil with viscosity of 0 051 336 6 mpa s we compared the results for breakdown pressure the distribution and fracturing mechanism of acoustic emission ae and the microstructure of induced cracks revealed by using an acrylic resin containing a fluorescent compound fracturing with low viscosity fluid induced three dimensionally sinuous cracks with many secondary branches which seem to be desirable pathways for enhanced geothermal system egs shale gas recovery and other processes

western norwegian fjord sediments age volume stratigraphy and role as temporary depository during glacial cycles abstract the sediments in the western norwegian fjords are described chronologically qualitatively and quantitatively by means of seismic profiling and correlation with dated terrestrial sediments along the fjords five chronostratigraphic units i v are proposed for the fjord sediments using the well established quaternary stratigraphy in the area sediment volumes of the main fjords are calculated using a dense seismic grid combined with map analyses approximately 150 km 3 of sediments are present in the fjords between 59 63 n ninety percent of this material is considered to be deposited during deglaciation of the last weichselian ice sheet less than ten percent of the fjord sediments in this area is older than the last glacial weichselian maximum both glacial and glaciofluvial processes are active in emptying the fjord basins and transporting the sediments to the continental shelf and slope during glaciations

correlation of late quaternary moraines impact of climate variability glacier response and chronological resolution abstract the last decade has seen a global surge in the number and resolution of well dated geomorphological reconstructions of mountain glacier fluctuations and former ice sheet extents this has been facilitated by the widespread deployment of large samples of terrestrial cosmogenic nuclide dating tcnd allowing more sophisticated probability analyses for reducing the statistical uncertainty of moraine ages and testing of correlations at local regional and hemispheric scales geochronological advances in the field laboratory and on model calibration have taken place in parallel with modelling of palaeoclimate based on glacier reconstructions and of glacier sensitivity to temperature and precipitation forcing in spite of these advances basic conceptual issues remain this review questions whether the technical leap forward in dating has encouraged us to over reach our interpretive limits particularly in terms of the concept and practice of correlation we propose that to enable reliable correlation glacier chronologies should first be examined for their climatic integrity spatial coherence and chronological robustness even with excellent dating interpretive complexity remains due to complex climate signals and glacier response characteristics and to erosion censoring of the landform record all are issues which must be addressed to avoid either spurious lumping correlation or splitting differentiation of glacier chronologies and thus misinterpretation of the climatic significance of reconstructed glacier advances we suggest that the reliability of correlation is no better than the weakest link in the chain of reasoning which connects climatic fluctuations with dated landforms and sediments improved dating means that poor chronological resolution is less likely to be the limiting factor for correlation but shifts the focus onto other less quantifiable sources of uncertainty these conceptual statements are exemplified with reference to holocene glacial chronologies of contrasting mid latitude environments in southern norway iceland and new zealand

erosion rate of a younger dryas cirque glacier at krakenes western norway an erosion rate of 0 5 to 0 6 mm a 1 is deduced for a younger dryas cirque glacier the erosion period of 700 a was determined from the laminated glaciolacustrine sediments in a small lake just outside the end moraine of the cirque and radiocarbon dates obtained below and above these sediments the volume of eroded bedrock was calculated from measurements of the deposited sediments of which the end moraine the glaciofluvial delta and the glaciolacustrine sediments are most important with a constant erosion rate the cirque could have formed in 83 to 125 000 a

debris transport by loch lomond readvance glaciers in northern scotland basin form and the within valley asymmetry of lateral moraines moraines in six cirques in northern scotland are shown to be asymmetrically developed being larger below north or east facing valley sides moraine asymmetry is strongly correlated with the distribution of free faces in the valleys a relationship that is interpreted as the result of variation in slope retreat rates analysis of clast form and roundness demonstrates that following initial release from bedrock debris entered both passive high level glacial transport and tractive transport at the ice bed interface the importance of glacier velocities and medial moraines on debris flux is discussed consideration is also given to the implications of process asymmetry to long term landform development

a revised approach to discriminating sediment transport histories in glacigenic sediments in a temperate alpine environment a case study from fox glacier new zealand clast shape measurements have developed into a standard method for reconstructing the transport histories of sediments in glacial environments the majority of studies use the ra c40 covariance approach with some researchers routinely including clasts of varying lithologies within their samples the corollary is that variable lithological properties may control clast form and roundness rather than debris transport mechanisms despite this the role of lithology on clast shape in glacial environments has rarely been analysed furthermore some studies have reported difficulties in using the ra c40 co variance plot in discriminating clasts that have undergone subglacial transport and clasts that have been modified by fluvial activity results from a glacierized valley in a temperate alpine setting indicate that detailed analysis of clast shape where samples are of uniform lithology although time consuming is a useful tool in the investigation of deposits in glaciated environments copyright 2012 john wiley sons ltd

small scale earthquake mechanisms induced by fluid injection at the enhanced geothermal system reservoir soultz alsace in 2003 using alternative source models the geothermal reservoir at soultz sous forets is a valuable natural laboratory for understanding the mechanisms of microearthquakes generated during stimulations and circulation tests an ongoing effort currently exists regarding the retrieval of mechanisms aimed to indicate the type of fracturing of the rock massif as a default a moment tensor description has been applied nevertheless the retrieval of the mode of fracturing still remains ambiguous recent studies indicate a prevailing shear slip but rarely a non shear pattern has also been observed the moment tensor used today as a universal tool for descriptions of the mechanism captures general balanced dipole sources however in the case of small scale earthquakes the moment tensor need not always be reliably determined in an effort to fit the data there may be notable non shear components caused by the low quality of input data constraining the source model to directly determine a simpler one is convenient for describing the physical phenomena expected for a particular focus an opening of new fractures can be described to a first approximation by a tensile crack optionally combined with a shear slip such an alternative model is called a shear tensile crack stc source model the combination is practical and can be used to both identify events that reflect purely mode i tensile failure and to determine the dilation angle of the fracture undergoing shear the latter is particularly important in enhanced geothermal system reservoirs such as soultz where shear related dilation is believed to be the primary mechanism underpinning permeability creation during stimulation injections we performed a synthetic case study by simulating seismic data as recorded by the actual seismic array installed at soultz sous forets synthetic p and s amplitudes for several shear tensile source models were inverted for several types of station coverage the analysis explored how results were influenced by mislocation mismodeling and noise contamination of data in most cases the orientation of the mechanism was well resolved determination of shear vs non shear content within the mechanism was more difficult from all of the factors influencing resolution that we explored the quality of the monitoring system the number of stations and their distribution with respect to the focus and noise contamination were of the highest impact the stc source model yielded considerably less spurious non shear fracture components than the moment tensor from the bulk of the seismicity recorded during the stimulation in 2003 we concentrated on the first phase of the injection when only a single borehole at the site was stimulated we processed thirteen small earthquakes with magnitudes larger than 1 4 that were not treated in previous studies we determined that their source mechanisms were dominantly pure shear slips on pre existing faults just as the earthquakes investigated earlier were the results were also in agreement with the stress pattern from in situ measurements

geomorphological consequences of a glacier advance across a paraglacial rock avalanche deposit abstract glacial reworking of paraglacial rock slope sediment has been inferred from long deglaciated terrains to contribute significantly to glacial sediment transfer at feegletscher switzerland we provide the first description of the geomorphological consequences of glacier advance across paraglacial rock avalanche sediment this produced a small arcuate end moraine that encloses a zone of hummocky debris the sedimentology of these landforms is conditioned by rock avalanche sediment and can be differentiated from purely glacial sediments indicating that the contribution of glacially reworked rock avalanche debris may be recognisable in deglaciated terrain remarkably much of the overridden rock avalanche debris has maintained its angularity and delicate brecciation features despite up to 40 years of glacial action we suggest that the surface carapace facies of the rock avalanche deposit comprising large openwork blocks limited the effectiveness of glacial erosion processes the carapace facies will have resisted significant erosion by the relatively thin glacier because of its high shear strength and because it was able to transmit subglacial meltwater efficiently thus enhanced debris transfer associated with reworking of paraglacial rock avalanche sediment should not necessarily be expected during the initial stages of glacier advance

the lacustrine sedimentary sequence in sygneskardvatnet western norway a continuous high resolution record of the jostedalsbreen ice cap during the holocene abstract two lacustrine sediment cores from sygneskardvatnet sunndalen confirm that at least the northern part of the jostedalsbreen ice cap melted away during the atlantic chronozone between 6475 and 5300 14 c yr bp 7340 and 6150 cal bp possibly interrupted for short intervals of glacier activity around 6000 and 5800 14 c yr bp 6900 and 6700 cal bp prior to this periods of glacier expansion culminated at ca 8500 8400 8200 7750 7600 and 7400 cal bp the 8400 8200 cal bp advances are correlated with the widespread 8200 event finse event recorded in greenland ice cores lacustrine and proglacial sites and marine sediments during the early part of the holocene periods of glacier contraction culminated at ca 8450 8300 7900 7500 and 6250 cal bp of which the last represents climatic optimum conditions lowest supply of minerogenic sediments and or highest organic production the sedimentary record also shows that the ice cap has existed continuously since 5300 14 c yr bp 6150 cal bp neoglaciation involved three main phases 1 6150 4500 cal bp 2 4500 2700 cal bp 3 2700 cal bp to the present and a series of low amplitude glacier advances which occurred at 6000 5800 5700 5600 5500 5200 5100 4900 4800 4700 4550 4450 4300 4200 4150 4050 4000 3900 3800 3550 3300 2550 2450 2350 2250 2150 2000 1800 1700 1600 1400 1300 1150 1050 and the 1000 cal bp including the little ice age loss on ignition analyses indicate however that episodes of less glacier activity occurred during the mid and late holocene at around 5900 5800 5550 5450 5300 5050 4850 4750 4500 4400 4100 3950 3700 3450 3100 2650 2500 2400 2300 2200 1850 1700 1550 1350 1250 1050 1000 cal bp and during the twentieth century altogether the lacustrine record from sygneskardvatnet indicates that the holocene has been interrupted by 41 periods of increased glacier activity mean return period of ca 150 years and by 36 events of glacier contraction mean return period of 210 years spectral analysis of the loi data show peaks at periods of about 50 85 110 250 285 500 and 2000 calendar years the mean time resolution in core sygneskardvatnet 2 is ca 20 yr cm 1 while the mean sedimentation rate is 0 5 mm yr 1

seismicity induced by hydraulic fracturing in shales a bedding plane slip model passive seismic monitoring of microseismic events induced in oil or gas reservoirs is known as microseismic monitoring microseismic monitoring is used to understand the process of hydraulic fracturing which is a reservoir stimulation technique we use a new geomechanical model with bedding plane slippage induced by hydraulic fractures within shale reservoirs to explain seismicity observed in a typical case study of hydraulic fracturing of a shale gas play in north america microseismic events propagating from the injection point are located at similar depths within the uncertainty of their locations and their source mechanisms are dominated by shear failure with both dip slip and strike slip senses of motion the prevailing dip slip mechanisms have one nearly vertical nodal plane perpendicular to the minimum horizontal stress axis while the other nodal plane is nearly horizontal such dip slip mechanisms can be explained by slippage along bedding planes activated by the aseismic opening of vertical hydraulic fractures the model explains the observed prevailing orientation of the shear planes of the microseismic events as well as the large difference between seismic and hydraulic energy

observations on terminal moraine ridge formation during recent advances of southern norwegian glaciers abstract the formation of terminal moraines dating from glacier advances during the a d 1990s was investigated at six temperate glaciers in the jostedalsbreen and jotunheimen regions of southern norway morphological and sedimentological information was analysed and combined with detailed observations photographic evidence and length variation measurements bulldozing pushing of proglacial sediments was the predominant process at the low lying glacier termini of the debris free outlets of the jostedalsbreen ice cap evidence for bulldozing includes the relocation and rotation of boulders and the presence of lichen covered boulders in the distal slopes of moraines differences in moraine sedimentology between the individual sites are attributed to variations in the pre existing material pushed up rather than to specific processes in jotunheimen several modes of moraine ridge formation were active dumping of supraglacial debris and the marginal freezing on and subsequent melting out of subglacial sediment slabs were more important than bulldozing at some sites and in some years low air temperatures in winter at the higher altitude glacier termini enabled freezing on to occur however the forelands are below the lower limit of discontinuous permafrost and evidence of thrusting is absent whereas discrete terminal moraine ridges at jostedalsbreen are related to seasonal advances the less dynamic glaciers of jotunheimen allow the accretion of successive ridges during consecutive years no single regional mode of moraine formation is characteristic for southern norway several processes are involved depending on individual glacier morphology and dynamics the glaciological regime and environmental conditions especially climate on the glacier forelands the importance of specific processes varies within and between glacier forelands thus spatial and temporal variation and local individuality has to be taken into account in the interpretation of moraine ridge formation similar variability is likely to have been characteristic of terminal moraines deposited during the little ice age and earlier in the quaternary

an improved method for seismic moment tensor inversion of acoustic emissions through assessment of sensor coupling and sensitivity to incidence angle 1 introductionae analysis is frequently used in laboratory experiments asa method to describe the spatio temporal evolution of damage furthermore characterization of the ae sources provides insightinto the micromechanical processes involved in the initiation andcoalescence of cracks in rock samples 1 ae source mechanismanalysis provides additional information on the orientation andmechanisms of individual cracks during nucleation and formationof a fracture 2 simple techniques estimating the faultingmechanisms are based on average polarities 3 using dilatationaland compressional rst p wave motions this allows separatingrecorded aes into tensile shear and compaction sources themoment tensor mt represents a measure of the deformation inthe seismic source 4 it is commonly used to provide informationon fault plane parameters strike dip and rake of the fault thedecomposition of the mt allows estimating the ratio of the volu metric and non volumetric strain in the seismic source e g 5 themt inversion carries information on non double couple ndc anddouble couple dc components in earthquake sources providinginformation onprocesses involved in uid induced seismicity 6 10 and mining induced seismicity 11 13 collins et al 14 investi gated the source mechanisms of seismic events related to fracturingof tunnel walls sixteen ae sensors frequency band 40 400 khz were used to calculate seismic mts of extremely small seismicevents m

reconstructing the transport history of glacigenic sediments a new approach based on the co variance of clast form indices abstract two indices are used to describe the aggregate shape and roundness characteristics of glacially transported clasts the c40 index the percentage of clasts with c a ratios 0 4 and the ra index the percentage of very angular and angular clasts in a sample analysis of the between and within sample co variance of these indices provides a powerful tool for discriminating actively and passively transported clasts in glacigenic deposits use of these indices is illustrated in an analysis of the form characteristics of clasts from lateral and frontal moraines at storbreen jotunheimen these fall between those of actively transported clasts in basal till low c40 and ra values and those of unmodified frost weathered clasts high c40 and ra values both indices decline down moraine within sample analyses of clast shape demonstrates that these aggregate clast form gradients reflect changes in the relative proportions of actively and passively transported debris on the moraines rather than progressive modification of actively transported clasts these analyses also indicate that actively transported clasts form the dominant component of the moraines particularly near the former glacier terminus further applications of the approach developed here are suggested

very low inheritance in cosmogenic surface exposure ages of glacial deposits a field experiment from two norwegian glacier forelands terrestrial cosmogenic nuclide dating has been widely used to estimate the surface exposure age of bedrock and boulder surfaces associated with deglaciation and holocene glacier variations but the

little ice age variations of outlet glaciers from the jostedalsbreen ice cap southern norway a regional lichenometric dating study of ice marginal moraine sequences and their climatic significance complex moraine ridge sequences in front of seven outlet glaciers of the jostedalsbreen ice cap austerdalsbreen bergsetbreen fabergstolsbreen lodalsbreen stegaholbreen tuftebreen bodalsbreen are dated using families of lichenometric dating curves established previously at an eighth outlet nigardsbreen applicability of the nigardsbreen curves at the regional level is tested using independent historical evidence moraines deposited during the present century are dated to an accuracy of 9 4 yr 16 0 and most of them are dated to an accuracy of 5 5 yr 9 4 results from the moraine sequences are combined to form a composite jostedalsbreen record median predicted dates for moraine ridges cluster around ad 1939 2 yr 1929 3 1908 3 1886 5 1875 2 1867 4 1855 3 1842 5 1822 5 1807 4 and 1785 5 at least four glaciers reached their little ice age maxima prior to ad 1780 two nigardsbreen and bodalsbreen at ca 1750 one fabergstolsbreen at ca 1705 stegaholbreen attained its maximum ca 1863 since the little ice age maximum and despite large differences in glacier size frontal variations of the various outlets have exhibited a high degree of synchroneity which suggests that the moraine sequences contain a sensitive record of high frequency climatic variations over the last ca 250 yr during the early twentieth century measured readvances of the order of 5 150 m over 1 10 yr led to moraine formation dendroclimatic evidence indicates that since the late eighteenth century moraine ridges formed about 5 yr after summer temperature minima and correlate with runs of cool summers temperature depression of 0 5 1 0 c below the ad 1700 1950 average almost simultaneous glacier advances appear to have been caused by reduced ablation this near immediate response to climatic variation by glacier tongues that descend to relative low altitudes is superimposed upon the longer term dynamic response of the ice cap to climate

organic geochemistry of the eagle ford group in texas a comprehensive regional organic geochemical study was performed on outcrop and core samples from the eagle ford group with the aim of determining variations in organic matter source thermal maturity and depositional environments total organic carbon toc and rock eval pyrolysis parameters show that the eagle ford group has excellent hydrocarbon source rock potential and is dominated by type ii kerogen distributions of regular steranes hopanes and monoaromatic steroids confirm a marine carbonate depositional environment aryl isoprenoid ratios suggest the occurrence of intermittent photic zone anoxia the n alkane and sterane distributions and the presence of pregnanes homopregnanes and gammacerane suggest deposition under hypersaline conditions particularly in west and east texas in east texas biomarkers indicate that the eagle ford group was partially sourced from terrigenous organic matter and deposited under oxic suboxic conditions thermal maturity parameters including the temperature at which the peak corresponding to the compounds produced from the thermal degradation of kerogen in the rock eval chromatogram maximizes tmax vitrinite reflectance and biomarker ratios indicate that in west and central texas the eagle ford group is immature to marginally mature in southwest texas it is in the oil to dry gas window and in east texas the eagle ford is in the main stage of oil generation geochemical logs of biomarker ratios show that the lower eagle ford formation has the highest toc and hydrogen index particularly in the lozier canyon member experienced stronger anoxic conditions during deposition and has lower clay content compared with the upper eagle ford formation geochemical parameters show that the latter may have received an additional siliciclastic and terrigenous organic matter input under oxic dysoxic conditions isotope data indicate a marine organic matter source for the eagle ford group but surprisingly 13c values do not show significant organic facies depositional environment or thermal maturity variations

contemporary suspended sediment transfer and accumulation processes in the small proglacial saetrevatnet sub catchment bodalen western norway a combination of different process monitoring lake sediment coring and sediment analysis methods and techniques was applied in the 17 5 km2 saetrevatnet sub catchment in the upper bodalen drainage basin nordfjord western norway in order to define hydro meteorological controls on runoff suspended sediment transfer and sediment accumulation and to determine the role of lake saetrevatnet within the drainage basin wide sediment routing system the proglacial system shows the typical seasonal and weather depended runoff variations for glacierized drainage basins significant suspended sediment transport is associated to summer glacier melt when 61 9 of the annual suspended sediment yield was recorded in 2010 as well as to single rainfall events when 19 8 of the annual suspended sediment yield was recorded in 2010 the intensity of atmospheric energy input and the frequency of heavy rainfall events were found to be critical for the rate of suspended sediment transport within the saetrevatnet sub catchment the computed annual suspended sediment yield from the proglacial area was 24 2 t km 2 which is notably lower as compared with a number of other glacierized basins worldwide delta accumulations rates from 2009 4 cm yr 1 and 2010 3 cm yr 1 as well as average annual delta advance ranging from 3 8 m to 4 6 m confirm the calculated high annual lake sedimentation rate of 1 7 cm yr 1 lake saetrevatnet 0 02 km2 currently traps about 80 85 of the sediments delivered from the upstream located glacial system highlighting the importance of small ephemeral proglacial lakes within larger valley fjord sediment routing systems

holocene glacier fluctuations of flatebreen and winter precipitation changes in the jostedalsbreen region western norvay based on glaciolacustrine sediment records the history of holocene glacier variations of flatebreen an independent glacier close to the sw part of the jostedalsbreen ice cap has been reconstructed from lacustrine sediments in the proglacial lake jarbuvatnet the sedimentary succession shows evidence of three maini episodes of holocene glacier expansion the first is recorded in the basal part of the core up to 370 cm according to the age depth relationship in the sediment core based on 12 ams radiocarbon dates this glacier expansion episode terminated about 10200 cal yr bp the second major glacier phase lasted from 8400 to 8100 cal yr bp while the third was initiated around 4000 cal yr bp and has continued up to the present at 43 cm in the core the medium silt content increases significantly accompanied by a minor increase in the sand content this textural change is interpreted as the first time that the tenninus of flatebreen extended inlto an upstream lake at 1083 m a s l the age model suggests that this event took place around