schmidt hammer exposure age dating shd performed on periglacial and related landforms in opplendskedalen geirangerfjellet norway implications for mid and late holocene climate variability schmidt hammer exposure age dating shd was applied to a variety of boulder dominated periglacial landforms in an attempt to establish a local mid late holocene chronology for the geirangerfjelle

the impact of landscape change on the significance of political centres along the lower elbe river in the 10th century a d abstract the hohbeck an insular elevation in the middle of the vast elbe river floodplain was a strategically important place in the early and high middle ages this is reflected in an unusually high density of strongholds the meetschow site was of major importance for several centuries even when political power changed saxons franks slavs and germans all kept their main fortification at this place obviously because of its topographical position controlling the intersection of a water route and a land route the significance of meetschow ended with the end of the 10th c and was declining until the final abandonment lenzen on the other bank of the river took over the functions of meetschow and developed into the administrative and political centre of the region geoarchaeological research revealed evidence for a short phase of heavy natural flooding events sometime between 950 and ca 980 a d its impact on the topographical situation around the hohbeck is discussed in the light of the political situation the paper focuses on the coincidences in the history of strongholds and flood activity in the 8th 10th c at the hohbeck it is stressed that the documented large scale natural events should be possible to detect in a wider area of northern europe

analysis of gully dimensions and sediment texture from southeast australia for catchment sediment budgeting abstract catchment scale sediment budgeting models are increasingly being used to target remediation works aimed at controlling erosion and improving water quality gully erosion is often a major sediment source and needs to be accounted for in such models in a manner consistent with the scale of analysis and available data using 130 measurements of gully cross sectional area and 45 measurements of gully wall sediment texture the variability in gully dimensions and particle size distribution for the lake burragorang catchment in australia is examined the distribution of gully cross sectional area measurements is log normally distributed and modelling indicates a representative value of 23 m 2 be used in catchment sediment budgeting applications the proportion of gully eroded sediment contributing to the bedload budget defined as particles 63 m diameter of a river link is approximately half though may be higher in igneous landscapes a continental scale spatially distributed subsoil texture dataset provided limited capacity to predict the finer scale spatial variation in the proportion of sediment contributing to bedload from gully erosion within the lake burragorang catchment

cosmic ray labeling of erosion surfaces in situ nuclide production rates and erosion models a number of in situ cosmogenic radionuclides and stable nuclides have been measured in natural exposed rock surfaces with a view to study their in situ production and rock erosion rates 1 the in situ radionuclides can be used for a high resolution tomography of the erosional history of an exposed surface two stable nuclides 3he 21ne and five radionuclides 10be 26al 36cl 14c 39ar having half lives in the range of 300 1 5 106 yr half life are measurable in many rock types a prerequisite for the application of the in situ nuclides for the study of erosional histories of surfaces is a knowledge of their production rates under different irradiation conditions altitude latitude irradiation geometry and shielding relative nuclide production rates can be determined fairly accurately using the extensive available data on cosmic ray neutrons 2 absolute nuclide production rates cannot generally be predicted with any accuracy because of lack of data on excitation functions of nuclides unless some normalization is possible as was done in the case of several cosmic ray produced isotopes in the atmosphere 3 based on a recent natural calibration experiment in which erosion free surfaces exposed to cosmic radiation for 11 000 yrs were sampled the absolute production rates of 10be and 26al in quartz have been accurately estimated for mountain altitudes in sierra nevada 4 the absolute production rates of 10be and 26al in quartz can therefore be estimated fairly accurately for any given latitude and altitude some measurements of 14c in rocks of low erosion rate 5 similarly allow an estimate of its production rate attempts made to measure the in situ production rates of 3he in rocks have not yet led to a convergent production rate in view of the importance of knowing the production rates of isotopes of he ne and ar i present here theoretical estimates of their production rates based on available cross section data i discuss the information that can be extracted from the study of the in situ nuclides in rocks useful parameters characterizing the exposure history of a rock surface are 1 the effective surface exposure age and 2 the time averaged erosion rate the implications of these parameters for single and multiple nuclide studies are discussed in terms of the erosion models considered

the influence of paleogeography in epicontinental seas a case study based on middle devonian strata from the mackenzie basin northwest territories canada abstract the history of middle devonian sea level changes are recorded in the chinchaga formation lonely bay formation horn plateau formation and the horn river formations that originated in the mackenzie basin which is located in the southern northwest territories canada these strata record an almost consistent sea level rise throughout the middle devonian with punctuated deepenings deposition began in the mackenzie basin in the eifelian with restricted shallow water evaporites and dolomites of the chinchaga formation overlying the chinchaga formation are the open marine carbonates belonging to the lonely bay formation which were overlain by the horn plateau formation buildups pelagic shales of the horn river formation in the late givetian early frasnian later covered these buildups during the early and middle devonian many continental basins in north america had limited interactions with open ocean waters these restricted shallow water basins were vulnerable to the effects of clastic shedding and evaporitic drawdown that commonly caused local lowstands several of these shallow basins including the mackenzie basin have been used to construct devonian sea level curves comparison of the middle devonian strata that formed in the mackenzie basin with well established sea level curves shows that the late givetian regression interpreted from some of those successions is not evident in the succession found in the mackenzie basin this probably reflects the fact that the mackenzie basin was directly linked to the open ocean and was not influenced by the changes in sea level that affected many of the enclosed basins

geomorphology and weathering characteristics of erratic boulder trains on tierra del fuego southernmost south america implications for dating of glacial deposits abstract erratic boulder trains ebts are a useful glacial geomorphological feature because they reveal former ice flow trajectories and can be targeted for cosmogenic nuclide exposure dating however understanding how they are transported and deposited is important because this has implications for palaeoglaciological reconstructions and the pre exposure and or erosion of the boulders in this study we review previous work on ebts which indicates that they may form subglacially or supraglacially but that large angular boulders transported long distances generally reflect supraglacial transport we then report detailed observations of ebts from tierra del fuego southernmost south america where their characteristics provide a useful framework for the interpretation of previously published cosmogenic nuclide exposure dates we present the first comprehensive map of the ebts and analyse their spatial distribution size and physical appearance results suggest that they were produced by one or more supraglacial rock avalanches in the cordillera darwin and were then transported supraglacially for 100 s of kilometres before being deposited rock surface weathering analysis shows no significant difference in the weathering characteristics of a sequence of ebts previously hypothesized to be of significantly different age i e different glacial cycles we interpret this to indicate that the ebts are much closer in age than previous work has implied this emphasises the importance of understanding ebt formation when using them for cosmogenic nuclide exposure dating

the 21ne production rate in quartz revisited abstract i have revised our earlier production rate determination of 21ne in terrestrial quartz s niedermann th graf j s kim c p kohl k marti and k nishiizumi 1994 earth planet sci lett 125 341 355 taking account of improved knowledge about the exposure age of samples used in that work and applying distinct procedures for scaling to sea level and high latitudes the corrected value of 19 0 3 7 atoms g 1 a 1 is in excellent agreement with expectations based on nuclear properties j masarik and r c reedy 1995 earth planet sci lett 136 381 395 and closely corresponds to the present day production rate in the case of substantial variations of the geomagnetic field in the past as proposed by several studies the revised value can consistently be used with suitable correction methods

development of gullies and sediment fans in last glacial areas on the example of the suwalki lakeland ne poland abstract the density of gully network in the suwalki lakeland northeastern poland with typical last glaciation relief is 0 2 km km2 on average and locally reaches 1 2 km km2 most gullies are isolated but sporadically they create dendritic patterns the larger gullies are developed along dellies bowl shaped dry valleys or melt out valleys the smaller and shorter gullies occur on the slopes of melt out depressions and tunnel valleys ages of peat covered by fans at the mouths of larger gullies indicate that gully erosion started between 3520 70 to 2240 100 bp two different units build the fans and infilled the gullies the older unit in the lower part of fans is up to 5 m thick contains sand and gravel that generally originated from the bottom and bank erosion of the gullies and resembles alluvium the younger unit about 2 3 m thick consists of colluvium the fans at the mouths of smaller and shorter gullies are mainly built of colluvium the maximal grain diameter in both units is similar which testifies to a similar intensity of extreme rainfalls the analysed sediments have different characteristics which indicate that the source material and depositional changes are linked to forest clearance and farmland expansion starting in the 7th century ad and continuing in the middle ages

gully morphology hillslope erosion and precipitation characteristics in the appalachian valley and ridge province southeastern usa this study investigates gully erosion on an east tennessee hillslope in a humid subtropical climate the study area is deeply gullied in ultisols acrisol according to the world reference base for soil with thirty years of undisturbed erosional history with no efforts to correct or halt the erosion the objectives are 1 to examine how different gully morphologies channel sidewall and interfluve behave in response to precipitation driven erosion and 2 to identify an appropriate temporal scale at which precipitation driven erosion can be measured to improve soil loss prediction precipitation parameters total accumulation duration average intensity maximum intensity extracted from data collected at an on site weather station were statistically correlated with erosion data erosion data were collected from erosion pins installed in four gully systems at 78 locations spanning three different morphological settings interfluves channels and sidewalls kruskal wallis non parametric tests and mann whitney u tests indicated that different morphological settings within the gully system responded differently to precipitation p 0 00 for channels and sidewalls regression models relating erosion and precipitation parameters retained antecedent precipitation and precipitation accumulation or duration r2 0 50 p 0 00 for channels r2 0 28 p 0 00 for sidewalls but precipitation intensity variables were not retained in the models for interfluves less than 20 of variability in erosion data could be explained by precipitation parameters precipitation duration and accumulation including antecedent precipitation accumulation were more important than precipitation intensity in initiating and propagating erosion in this geomorphic and climatic setting but other factors including mass wasting and eolian erosion are likely contributors to erosion high correlation coefficients between aggregate precipitation parameters and erosion indicate that a suitable temporal scale to relate precipitation to soil erosion is the synoptic time scale this scale captures natural precipitation cycles and corresponding measurable soil erosion

surface and sub surface schmidt hammer rebound value variation for a granite outcrop this study presents rock strength variations at granite outcrops and in subsurface vertical profiles in the jizerske hory mountains czech republic schmidt hammer rebound values in subsurface profiles change gradually from the bedrock surface downward an exponential relation has been observed between the r values and depth in rock outcrops to a depth of around 4 5 m the exponential nature of the curve indicates that rock hardness increases more rapidly with depth in the uppermost 1 m section of the rock profile a detailed study of rebound values obtained from both intact and polished rock exposures reveal effects of surface grinding on results of the schmidt hammer method the range of data collected increases after grinding allowing more precise discrimination of rock surfaces in respect of age and weathering the schmidt hammer method may be used effectively as a relative age dating tool for rock surfaces that originated during the late pleistocene it is concluded that this time limitation can be significantly mitigated by surface grinding before measurement copyright 2010 john wiley sons ltd

downstream hydraulic geometry and channel adjustment during a flood along an ephemeral arid region drainage in september 1997 a dissipating tropical storm caused a flood with an estimated maximum discharge of 240 m 3 s along yuma wash an ephemeral braided system draining 186 km 2 in southwest arizona older high water marks that record a flood peak of 1280 m 3 s provide a reasonable estimate for the probable maximum flood along the wash detailed channel crosssectional surveys during 1995 and again in 1998 6 months after the 1997 flood facilitated examination of downstream hydraulic geometry and channel adjustment during the flood channel width increased substantially downstream exponent of 0 78 presumably because of low bank resistance whereas hydraulic depth and velocity had modest downstream increases 0 15 and 0 14 respectively channel aggradation generally occurred along wider braided reaches moreover degradation occurred in narrow reaches with fewer channels aggradation and degradation also appeared to be governed by a threshold relationship between flow depth and vegetated bars degradation occurred where flow was confined within a channel or subchannel at discharges sufficiently high to overtop vegetated bars greater roughness facilitated sediment deposition and channels aggraded a discriminant function correctly classified nearly 90 of the cross sections as scoured or filled using a single hydraulic variable maximum depth of flow during the dissipating tropical storm d 2002 elsevier science b v all rights reserved

distinguishing allogenic from autogenic causes of bed elevation change in late quaternary alluvial stratigraphic records abstract allogenic and autogenic mechanisms both cause changes in the bed elevation of rivers and thereby influence the characteristics of alluvial stratigraphic records asrs allogenic forcing mechanisms can be grouped into five categories whose relative influence varies with timescale climate tectonism base level land use land cover and direct human modification of channels late quaternary asrs are influenced by the greatest range of allogenic forcing variables with climate among the most important autogenic mechanisms of bed elevation change are ubiquitous throughout fluvial systems and are always time transgressive autogenic bed elevation change propagates through drainage networks at predictable rates and results in a time space envelope within which its effects are capable of operating asrs that can be correlated over geographical areas large enough and time intervals small enough to exist outside this envelope most likely result from allogenic forcing this formulation represents a quantitative and geographic set of threshold criteria for distinguishing between autogenic and allogenic mechanisms over late quaternary timescales 10 2 to 10 5 years in tectonically stable regions climate change is the dominant allogenic mechanism and therefore the first order control on the morphology sedimentology pedologic characteristics and chronology of alluvial stratigraphic records that meet or exceed the threshold criteria for demonstrating allogenic causality

influence of climate and dolomite composition on dedolomitization insights from a multi proxy study in the central oman mountains abstract dedolomitization is an important diagenetic process that can yield information on the history of paleo fluids in a given aquifer or outcrop and by extension it offers a window into past hydrologic conditions dedolomitization is also relevant economically as it can alter the porosity and permeability of carbonates thus affecting reservoir quality despite considerable research the process of dedolomitization is still not entirely understood here new findings from the central oman mountains highlight the importance of dolomite chemistry and fluctuating climate on dedolomitization petrographic mineralogical and geochemical data from both altered and pristine dolomite hosted in jurassic carbonate rocks from the sahtan group and outcropping at wadi mistal in the jebel akhdar tectonic window reveal two dolomite bodies with different characteristics stratabound and fault related dolostone the ferroan dolomite crystals are larger in the fault related dolostone whereas the non ferroan dolomite crystals are smaller in the stratabound dolostone petrography reveals a complex suite of alteration textures including pristine dolomite recrystallized dolomite and calcitized dolomite dedolomite iron oxides are present pervasively in the altered rocks and different alteration textures co occur in the same sample relative to unaltered dolomite in this outcrop the recrystallized dolomite is characterized by similar positive carbon isotope values but less negative oxygen isotope values and the calcitized dolomite is characterized by even less negative oxygen isotope values and more negative carbon isotope values based on field data and petrography two phases of alteration are evident an earlier dedolomitization event affecting the stratabound dolomite only and a more pervasive pleistocene holocene alteration phase associated with surface weathering that affected both the fault related dolomite and to a lesser extent the stratabound dolomite stable isotope results further suggest that the more recent subaerial weathering phase happened under two alternating climate regimes dedolomitization was triggered by meteoric fluids that interacted with soil related carbon during humid climatic period s whereas recrystallization of ferroan fault related dolomite happened during more arid climatic period s with less developed soils and lower fluid rock interaction these results suggest that weathering of ferroan fault related dolomite can lead to formation of goethite and recrystallized non stoichiometric dolomite with a reset stable oxygen isotope signature and sometimes to dedolomitization

cosmic ray produced 21ne in terrestrial quartz the neon inventory of sierra nevada quartz separates the study of cosmic ray produced radioactive and stable nuclides on the surface of the earth can provide relevant geomorphological and glaciological information at present the cosmic ray production rates of stable 21ne are not well known this study attempts to remedy the situation by determining the production rate ratio of 21ne and 26al p21p26 in quartz 26al concentrations and p26 rates have previously been investigated for quartz separates of sierra nevada rocks which were brought to the surface by glacial scouring during the tioga period at the end of the last ice age 1 we used splits of the same samples for our studies and found that ne in these rocks represents a mixture of several components trapped ne nucleogenic 21ne and 22ne produced by n reactions in oxygen and fluorine respectively as well as cosmic ray produced ne which is the component of interest in this study the trapped component was substantially lost in one sample w86 12 by crushing and by a density separation of the grain sizes 38 90 m and 90 125 m permitting the resolution of the in situ produced 21ne into cosmic ray spallation and n produced components and the determination of a lower limit to p21p26 in a second sample w86 8 one split contained small enough amounts of nucleogenic 21ne to permit the determination of a reasonable upper limit to p21p26 the two ratio determinations are consistent within error limits and the value adopted 0 65 0 11 2 agrees with ratios observed in extraterrestrial matter apparently p21p26 is thus not very sensitive to the neutron spectrum however the observed production rate ratio is substantially larger than theoretical estimates for si targets reflecting poorly known neutron excitation functions the above p21p26 value coupled to the observed 26al production rate 1 corresponds to a 21ne production rate of p21 21 atoms g 1 a 1 in quartz or to p21 45 atoms g si 1 a 1 at sea level and high latitudes this rate is based on an adopted exposure age of 11 000 yr for our quartz samples

age determination of glacially transported boulders in ireland and scotland using schmidt hammer exposure age dating shd and terrestrial cosmogenic nuclide tcn exposure age dating schmidt hammer exposure age dating shd was applied at 15 sites with glacially transported granite boulders in parts of northern and western ireland and southwest scotland that had been exposed by retreat of the last british irish ice sheet biis or younger dryas yd ice masses seven of these surfaces had previously been dated using terrestrial cosmogenic nuclide tcn exposure age dating application of the granite calibration equation of tomkins et al 2018c indicated a close correspondence between the shd ages and the tcn ages within 1 or 2 uncertainties these findings demonstrate that shd ages can be of comparable accuracy precision and reliability to tcn ages and are a strong argument for the more extensive use of shd in some quaternary dating projects however surface ages obtained by both shd and tcn dating should not be accepted uncritically they must be assessed in relation to the wider geological geomorphological and geochronological evidence evaluation of eight shd ages for which corresponding tcn ages are not available indicate that most are consistent with current theory and field evidence but some anomalous age estimates occur

orogenic pulses in the alberta rocky mountains radiometric dating of major faults and comparison with the regional tectono stratigraphic record radiometric ages from regionally distributed thrust fault gouge show that the eastward propagation of the southern rocky mountain fold and thrust belt in canada occurred in four orogenic pulses that correlate with tectonic events of the cordilleran interior and with depositional patterns in the adjacent foreland in the main ranges the pyramid 163 0 ma simpson pass 161 7 ma and johnson creek 145 7 ma thrusts were related to the initiation of thin skinned deformation from jurassic terrane accretion and were partly contemporaneous with development of the first clastic wedge in the foreland basin in the front ranges the emplacement of the greenock thrust 103 1 ma and broadview snake indian thrust 99 2 ma was contemporaneous with development of cenomanian deltaic deposits in the immediate foreland three thrusts in the front ranges rocky pass 74 8 ma sulfur mountain 75 6 ma and clearwater 74 2 ma thrusts define a campanian phase of tectonic loading that led to the last major transgression in the southern portion of the alberta foreland along the eastern margin of the front ranges the mcconnell thrust 54 0 ma together with the muskeg 52 4 ma brule 53 9 ma and nikanassin 52 1 ma thrusts in the foothills recorded the last phase of regional contraction the late jurassic mid cretaceous late cretaceous and early eocene deformation pulses are separated by relatively long periods 40 m y 20 m y and 10 m y of tectonic quiescence these spatially and temporally restricted fault motion pulses contrast with gradual forward fault propagation while regional eastward progression of deformation is preserved

burial dedolomite in the mississippian madison limestone wyoming and utah thrust belt abstract calcitization of dolomite in sedimentary carbonate sequences is often interpreted as a near surface process reflecting either an erosional unconformity within a sequence or late postburial weathering in the madison group of the western overthrust belt there is evidence of widespread dedolomitization petrographic isotopic and trace element analyses of madison dedolomite indicate that multiple phases of calcitization have occurred in several different diagenetic environments isotopic trends in replacement calcite suggest progressive burial interrupted by tectonic thrusting fracturing and uplift burial dedolomite in the madison limestone is characterized by depleted oxygen 8 0 18o pdb and carbon 8 6 to 17 5 13c pdb isotopic compositions relative to other replacive calcite phases introduction of depleted carbon into the system via hydrocarbon alteration is suggested by the depleted carbon isotopic composition of burial replacive calcite trace element data also indicate diverse origins for the various dedolomite phases the bu ial related dedolomite has low iron and manganese fe 200 ppm mn 30 ppm and moderate strontium sr 350 ppm while other replacive components have higher iron and manganese and trace levels of strontium

dolomitization of the middle devonian winnipegosis carbonates in south central saskatchewan canada the middle devonian winnipegosis carbonate unit in south central saskatchewan is partially to completely dolomitized two major types of replacive dolomite are distinguished microcrystalline to finely crystalline dolomite type 1 displays nonplanar a to planar s textures mimetically replaces the precursor limestone accounts for about four fifths of dolomite phases volumetrically and mainly occurs in the winnipegosis mounds and the lower winnipegosis member directly underlying the mounds medium crystalline dolomite type 2 shows planar s to planar e textures commonly occurs in the lower winnipegosis and brightholme members and decreases upward in abundance the 87 sr 86 sr ratios of type 1 dolomite 0ae70795 to 0ae70807 fall within the estimated sr isotopic range for middle devonian marine carbonates stratigraphic petrographic and geochemical data constrain the formation of type 1 dolomite to hypersaline sea water in a near surface environment after marine cementation and sub aerial diagenesis and prior to precipitation of the middle devonian leofnard salts movement of dolomitizing fluids could be driven by density differences and elevation head the shift to lower d 18 o values of type 1 dolomite 7ae 4t o 5ae1 vienna pee dee belemnite vpdb is interpreted as the result of recrystallization at elevated temperatures during burial type 2 dolomite has higher 87 sr 86 sr ratios 0ae70809 0ae70928 suggesting that the dolomite probably formed from basinal fluids with an increased richness in the radiogenic sr isotope in type 2 dolomite sr 2 concentrations are lower and fe 2 and mn 2 concentrations are higher compared with the associated limestone and type 1 dolomite type 2 dolomite is interpreted as having been formed from upward migrating basinal fluids during latest devonian and carboniferous period

from valley to marginal glaciation in alpine type relief lateglacial glacier advances in the piec stawow polskich roztoka valley high tatra mountains poland abstract the piec stawow polskich roztoka valley in the high tatras western carpathians features typical alpine type relief with a deeply incised glacial trough and large compound trough head cirque the prominent hypsographic maximum in the valley 1680 2000 m along with a broad cirque bottom had provided a vast space for recording glacial and periglacial landforms specifically the most recent lateglacial advances the valley has been intensively studied before in the context of glacial chronology in this paper we re establish the post last glacial maximum lgm glacial chronology of the valley via detailed geomorphologic mapping equilibrium line altitude ela reconstruction and schmidt hammer sh dating along with a critical review of previously published cosmogenic exposure age data 36 cl and lacustrine sediment chronology our results indicate that the first four of the five distinguished lateglacial stages roztoka i iii pusta i occurred before the bolling allerod b a interstadial thus virtually the entire valley became deglaciated in course of the oldest dryas cold phase a distinct reorganization of deglacial patterns from valley type to marginal type occurred before b a warming when the ela increased above the valley hypsographic maximum concentrated at the cirque bottom elevation it shows that noticeable deglaciation step can be caused due to topographic reason with a minimal climate forcing this points also to an important role of glaciated valley hypsography in regulating the distribution of moraines which is rarely taken into account in paleoglaciological reconstructions we infer that glaciers vanished in the tatra mountains during the b a interstadial later a renewed advance during the younger dryas pusta ii formed a nearly continuous festoon shaped pattern of moraines and rock glaciers in close distance to cirque backwalls furthermore we discus some paleoenvironmental significance of the geomorphological record in the valley as well the applicability of sh dating in constructing glacial chronology

long term pedolithogenic rhythms in the holocene abstract soil sedimentary series in subordinate accumulative and trans accumulative landscapes represent the most complete and detailed record of the development of soils topographic forms and local geosystems in the holocene a new conception of centuries long rhythms of soil formation and erosion is offered on the basis of literature analysis and original data on 80 pits within the east european plain supplied with 180 radiocarbon dates it is established that the holocene the last 10 500 years comprises seven stages of soil formation alternating with stages of intensive erosion and sediment accumulation 450 950 2300 2700 4200 4700 6300 6600 7700 8100 9500 10 200 bp the intervals of 450 150 1050 2300 2800 4200 4700 6200 6600 7700 8300 9500 and 10 200 10 400 bp correspond to the formation of soils in the geochemically subordinate footslopes gully bottoms floodplains landscapes the erosion lithogenetic stages are characterized by humid warm and cold and also arid cold climatic conditions the pedogenetic stages in subordinate landscapes of the forest steppe and forest zones fall mainly into arid warm and sometimes humid warm and arid cold climatic phases of the 2000 year long rhythm known as the shnitnikov rhythm

early diagenetic dolomitization and dedolomitization of late jurassic and earliest cretaceous platform carbonates a case study from the jura mountains nw switzerland e france early diagenetic dolomitization is a common feature in cyclic shallow water carbonates throughout the geologic record after their generation dolomites may be subject to dedolomitization re calcification of dolomites e g by contact with meteoric water during emersion these patterns of dolomitization and subsequent dedolomitization frequently play a key role in unravelling the development and history of a carbonate platform on the basis of excellent outcrops detailed logging and sampling and integrating sedimentological work high resolution sequence stratigraphic interpretations and isotope analyses o c conceptual models on early diagenetic dolomitization and dedolomitization and their underlying mechanisms were developed for the upper jurassic lower cretaceous jura platform in north western switzerland and eastern france three different types of early diagenetic dolomites and two types of dedolomites were observed each is defined by a distinct petrographic isotopic signature and a distinct spatial distribution pattern different types of dolomites are interpreted to have been formed by different mechanisms such as shallow seepage reflux evaporation on tidal flats and microbially mediated selective dolomitization of burrows depending on the type of dolomite sea water with normal marine to slightly enhanced salinities is proposed as dolomitizing fluid based on the data obtained the main volume of dolomite was precipitated by a reflux mechanism that was switched on and off by high frequency sea level changes it appears however that more than one dolomitization mechanism was active pene contemporaneously or several processes alternated in time during early diagenesis percolating meteoric waters obviously played an important role in the dedolomitization of carbonate rocks that underlie exposure surfaces cyclostratigraphic interpretation of the sedimentary succession allows for estimates on the timing of early diagenetic de dolomitization these results are an important step towards a better understanding of the link between high frequency probably orbitally forced sea level oscillations and early dolomitization under mesozoic greenhouse conditions

morphology and land use of floodplains in the western part of sandomierz basin southern poland central europe in the roman period abstract the roman period settlement zone east of krakow extends for 30 km along the vistula river valley settlement was closely related to morphological hydrological situations sites were located close to the terrace edge between ecosystems of the loess terrace and the floodplain with optimal conditions for multidirectional economic activities both agricultural and non agricultural moreover loess terrace flats were very convenient for land communication in contrast to the not easy accessible floodplain the vistula river served as a water route while small creeks supplied water to inhabitants although the same natural resources were available for inhabitants they were not utilized in the same way related to different settlement models in the roman period especially in the 3rd 4th cent ad an important role apart from developed agriculture was played by various non agricultural activities settlement sites can be divided into two zones according to results of the most recent wide scale research stable settlement also encompassed floodplains settlement in the vistula valley and on the raba alluvial fan was influenced by changing natural conditions subboreal deep 3 4 m incision of the vistula bed and channels of its tributaries resulted in development of a narrow lower floodplain the incision also produced good drainage of the higher floodplain occupying almost the whole valley bottom the effects of frequent floods were limited to intensive shaping of the lower floodplain on the higher level flood waters filled oxbows and backswamps the point bars and old meander belts remained unflooded and the settlement there was undisturbed beneficial for settlement in the floodplain was abundance of grazing ground for cattle access to oak wood used in buildings and other non agricultural activities and availability of material required in pottery production agricultural progress from introducing new improved tools enabled exploitation of more difficult fluvisols people living on loess terraces used small streams existing under the terrace edge in contrast access to water for inhabitants of floodplains was more difficult due to the lack of creeks and with relatively deeper water tables incision of river beds and draining of higher floodplains for that reason inhabitants of desert like floodplains had to dig wells stable and long standing settlement on the loess terrace developed non agricultural production dependent on resources acquired from the floodplain oak wood good quality loams and miocene clay from the outcrops on river banks used in pottery production the raba river valley in the vicinity of the workshops supplied materials of lower quality for pottery production

magnitude and chronology of extreme floods in the last 2 ka based on the stratigraphy of a riverine archeological site schurovo settlement middle oka river central european russia

new pollen data from paleosols in the moskva river floodplain nikolina gora natural and anthropogenic environmental changes during the holocene abstract in the floodplain of the moskva river near nikolina gora 3 well developed buried soils have been revealed the lower soil of boreal atlantic age a chernozem contains pollen of steppe plants but no pollen of conifers subboreal and subatlantic soils have light humus eluvial horizons subatlantic soils also have a well developed bt horizon the pollen data shows the distribution of the spruce forests in the second half of the holocene some signs of economic activities such as the pollen of ruderal plants and coal appear at the end of the formation of the atlantic soil and correspond to the neolithic in the subatlantic soils there are many traces of intensive development of the floodplain associated with the economic activity of the population of iron age and early middle ages the pollen and soil characteristics indicate deforestation of the floodplain and the continued existence of anthropogenic grasslands and meadows within a radius of 1 km from the settlements

erosion and sedimentation on the russian plain part 1 contemporary processes during the 1970s and 1980s the techniques of tillage and the area of cultivation on the russian plain remained virtually unchanged therefore it is possible to assess both the rate and forms of erosion and sedimentation over almost all of the plain for this period of several decades using the shi model and usle with coefficients derived for russian conditions observed gully density area and volume and a morphogenetic classification of streams it has been possible to produce an assessment of the current state of erosion and sedimentation the geographic patterns of both the rates and types of erosion and sedimentation are presented and partially explained this assessment will be of considerable value as a baseline against which to assess future changes as the area of cultivation and the methods of farming change as well as to assess historical erosion and deposition copyright 2003 john wiley sons ltd

rapid assessment of gully sidewall erosion rates in data poor catchments a case study in australia knowledge of erosion rates and sediment yields from gullies is critical for the effective prioritisation of management efforts aimed at reducing the impact of gully derived sediments on water quality this paper describes a rapid assessment method for estimating sidewall gully erosion rates for already established gully networks it combines a conceptual empirical model of the cycle of gully initiation and stabilisation with an easy to apply technique for assessing gully extent and dimensions the method is illustrated using a case study of the avon richardson catchment of north central victoria australia it is estimated that a total of 4 6 106tonnes of sediment have been generated in that catchment from gully erosion since the latest major phase of gullying in the mid 1800s this is equivalent to 8 9tha 1y 1 if sediment generation was evenly distributed spatially and temporally across the 3300km2 catchment over 160years prior to 2010 current rates of gully erosion are estimated to be 4700ty 1 equivalent to 1 4tha 1y 1 the results are comparable with observed rates of sidewall erosion in the avon richardson catchment further testing is required to build confidence in its applicability to assess sediment yields and for assisting regional authorities to plan remediation efforts

the schmidt hammer weathering and rock surface roughness measures of the differential relief of adjacent feldspar and pyroxene grains provide the first clear negative correlation of schmidt hammer rebound r values and degree of weathering however weathering and roughness are intimately related so the latter cannot be seen simply as a source of error limiting the utility of the schmidt hammer only where surfaces had similar textures prior to weathering can r values be compared directly even where surface texture is well controlled differences in r values should be viewed critically rather than assigned indiscriminately to differences in degree of weathering

the role of rock surface hardness and internal moisture in tafoni development in sandstone the development of cavernous weathering features such as tafoni remains poorly understood in particular the roles played by internal moisture and case hardening remain unclear in this study electric resistivity tomography ert has been used to map moisture distribution within inner walls of tafoni developed in sandstone and an equotip device used to measure rock surface hardness as a proxy measure of the degree of weathering and case hardening seven large tafoni in the golden gate highlands national park south africa varying in size and degree of development have been monitored a dynamic relationship between surface hardness degree of weathering and internal moisture regimes has been found we propose a new conceptual model which illustrates the complex interaction between case hardening and internal moisture and suggests a new direction for cavernous weathering research copyright 2011 john wiley sons ltd

dedolomitization and other early diagenetic processes in miocene lacustrine deposits ebro basin spain abstract a variety of meteoric diagenetic features reveal the development of a syngenetic karst on lacustrine deposits of the ebro basin diagenetic processes that operated on lacustrine laminated and stromatolitic carbonates include the following 1 a first syndepositional stage with processes such as dolomitization desiccation and related breccia formation and sulphate precipitation either as lenticular gypsum crystals or nodules this stage took place under progressive evaporation due to lake level fall when the previous carbonate deposits became exposed as a supra littoral fringe surrounding saline mud flats of adjacent sulphate depositional environments 2 a second early diagenetic stage in which processes such as sulphate dissolution and collapse brecciation dedolomitization calcite spar cementation and silicification occurred as a result of meteoric water input that caused a progressive rise in lake level light isotopic compositions 13 c and 18 o of diagenetic calcites versus heavier compositions in primary laminated and stromatolitic limestones confirm a meteoric influence the syngenetic karst is best developed at the boundary between two allostratigraphic units and coincided with one of the extensive stages of sulphate deposition at the end of the early miocene the karst facies occurred in an area that was a low relief barrier that separated two sites of sulphate deposition during low lake levels this indicates that the karst development was controlled by topographic changes within the basin and record a shift from arid to wetter climatic conditions as suggested by the overlying freshwater carbonate deposits the presence of diagenetic features such as those described in the central ebro basin affecting saline lacustrine carbonates is relevant because they can be used as indicators of subaerial exposure periods in terrestrial environments and they also reveal important palaeogeographic and palaeoclimatic events of basinal extent

methods for measuring rock surface weathering and erosion a critical review studies of rates processes and modes of rock surface and near surface deterioration and also hardening are central to rock weathering and building stone research conservation and management there is a need to measure and monitor weathering at the rock atmosphere interface to facilitate understanding of climatic environmental and lithological controls on the evolution and development of surface weathering features this paper reviews long established and recently developed field and laboratory methods used by geomorphologists to monitor and measure the impact of weathering and erosion on physical and mechanical properties of exposed rock surfaces and their immediate subsurface key advances are highlighted their application to multi scalar understanding and modelling of rock surface weathering in different contexts is discussed and potential future advances to provide new insights into rock weathering durability and materials conservation are identified in highlighting key advantages and disadvantages of a wide range of methods to the broader earth science community the paper aims to contribute to further innovative thinking across disciplines to develop new methods for measuring and monitoring rock weathering

buried late holocene luvisols of the oka and moskva river floodplains and their anthropogenic evolution according to soil and pollen data abstract according to radiocarbon dating the ages of the four major soils developed on the floodplains are as follows 1 modern 2 2500 800 cal bp 3 4700 3000 cal bp and 4 7000 5300 cal bp the late holocene soil 2 is usually defined as albeluvisol or luvisol it has a developed profile with clearly expressed argic horizons bt it is markedly different from the underdeveloped soil 1 fluvisol and soil 4 phaeozem or chernozem that have a dark humus mollic chernic horizon soil 2 has a typical light gray color of the humus horizon and is characterized by the accumulation of clay fraction in the bt horizon as compared with the overlying e horizon micromorphological data indicate that the bt horizon has well developed clay films on pore walls and on the surface of aggregates cultural layers belonging to the iron age or early middle ages are sometimes located in soil 2 pollen analysis of this soil attests to its development under forest vegetation which corresponds to the genesis of luvisols and albeluvisols however in some places near ancient settlements characteristic features of the e and bt horizons become weakly pronounced and a well developed dark humus umbric horizon is diagnosed in the soil profiles these soils are marked by the abundance of pollen of herbs including cultivated cereals and weeds this is evidently related to the anthropogenic activity and the propagation of secondary grassy and ruderal vegetation that replaced forests on the floodplains floodplain environments are considered unsuitable for the development of luvisols and albeluvisols within a larger part of the holocene these soils appeared on the floodplains in the late holocene in relation to the propagation of forest vegetation and extremely low floods within a relatively long time

the schmidt hammer in rock material characterization the schmidt hammer provides a quick and inexpensive measure of surface hardness that is widely used for estimating the mechanical properties of rock material however a number of issues such as hammer type normalization of rebound values specimen dimensions surface smoothness weathering and moisture content and testing data reduction and analysis procedures continue to influence the consistency and reliability of the schmidt hammer test results this paper presents a a critical review of these basic issues and b the results of tests conducted on granitic rocks of various weathering grades in the light of the conclusions of this review it was found that a very good correlation exists between l and n hammer rebound values and that both hammers are fairly sensitive to the physical properties particularly to dry density though less so to effective and total porosities the n hammer producing a lesser scatter in the data proved to be more efficient than the l hammer in predicting uniaxial compressive strength and young s modulus the exponential form of the correlation curves was found to reflect microstructural changes during the course of weathering and the differences in the probing scales or mechanisms in the means of measuring these mechanical properties and could be generalized to other crystalline igneous rocks the possibility of predicting weathering grades from rebound values was also explored the changes in the rebound values during multiple impacts at a given point produced a better indication of the weathering grade than a single impact value it was concluded that increasing the impact energy and plunger tip diameter should significantly reduce the scatter in coarse grained weathered rocks and hence improve the reliability of the schmidt hammer as a rock material characterization tool

past hydrological events reflected in holocene history of polish rivers abstract a database of 335 radiocarbon dates from holocene fluvial sediments in poland has been compiled each sample is characterized by 25 parameters all samples were grouped into one of 7 regions characterized by hydrological regime and one of 8 depositional environments statistical analysis was used to enhance the palaeoenvironmental data and 17 phases may be distinguished 10 of which have a distinct sharp peak abandoned paleochannels 149 dates clearly reflect the major wetter phases of the holocene an opposite picture is presented by overbank aggradation 86 dates connected mainly with expansion of agriculture preliminary correlations are made on peat bog records changes in vegetation lake water level rates calcareous tufa and speleothems growth landslides phases and debris flow phases these show many convergences explained by climatic fluctuations during the holocene

measurement and calibration of weathering using the schmidt hammer on wave washed moraines on the upper norrland coast sweden the schmidt hammer has for some years been used to measure the hardness of different rock surfaces and to date relatively boulders in moraine deposits in this paper applications on isostatically raised boulder beaches and rocky shores are described the research area is the northern swedish bothnian coast where present isostatic uplift is between 0 8 1 0 cm year 1 elevations above sea level can be converted to a timescale rebound values r of the schmidt hammer are correlated with the altitude and the degree of rock weathering can be estimated for each site eight sites with boulder beaches and nine sites with rocky shores have been analysed for boulder beaches correlation coefficients of 0 82 0 97 for weathering values r and the elevations above sea level were obtained for the rocky shores these values were calculated to 0 75 0 97 this method has applications in both geomorphology and archaeology for example a deep layer of weathered dolerite in the nordingra region which previously has been regarded as a post weichselian formation can be shown to be of pre weichselian origin several archaeological applications are also mentioned in the paper

dolomite calcitization and cement zonation related to uplift of the raisby formation zechstein carbonate northeast england abstract the raisby formation is the basal zechstein carbonate of northeast england it has undergone a complex diagenetic history during burial including multiphase dolomitization and replacement by sulphates upon uplift meteoric derived fluids have dissolved this replacive sulphate and precipitated calcite cements in the resultant porosity study of these cements by cathodoluminescence and trace element geochemistry shows that they are zoned and different cathodoluminescence zones correlate well with iron and manganese geochemical changes demonstrating a gradual increase in oxygenation of the precipitating fluids through time major diagenetic processes during cement growth include precipitation of anhydrite fluorite and barite calcitization of dolomite and internal sedimentation relating these processes to cement zonation allows this complex diagenesis to be explained in terms of uplift under the influence of meteoric derived groundwaters of constantly changing geochemical and electrochemical characteristics

age assessment and implications of late quaternary periglacial and paraglacial landforms on muckish mountain northwest ireland based on schmidt hammer exposure age dating shd abstract schmidt hammer exposure age dating shd was applied to a variety of late quaternary periglacial and paraglacial landforms composed of coarse rock debris on muckish mountain northwest ireland landform ages were determined using a linear high precision age calibration curve derived from young and old control surfaces of known age on the same rock type the shd ages represent maximum estimates of the time elapsed since the boulders stabilised and the landforms became inactive most ages are also minimum estimates for the start of landform development because older boulders are buried beneath the sampled surface boulders ages and 95 confidence intervals obtained for blockfield boulder lobes and talus indicate these features were likely active during several of the early holocene cold events evidenced in greenland ice cores and north atlantic sediment records activity ceased at different times 9 7 ka bp these landforms are the first indication of a geomorphological response to early holocene cooling in the oceanic mountains of ireland late holocene ages obtained for rock slope failure run out debris and debris cone boulders overlap with shifts to cooler and or wetter conditions including the little ice age geomorphological impacts associated with these changes in climate have not previously been recorded in the irish uplands the shd results indicate that previously implied timings for the stabilisation of some accumulations of coarse rock debris on mountain slopes are in need of revision

the schmidt hammer as a relative age dating tool and its potential for calibrated age dating in holocene glaciated environments the schmidt hammer is a relatively cheap portable sturdy instrument with proven value over the last two decades or so in rapidly dating coarse inorganic deposits of diverse origins early views were that its dating role was limited to distinguishing recently exposed from much older typically either a few sites of possibly different ages or occasional older surfaces amongst many young sites were studied more recently calibration curves based on individual r value means from small numbers 2 4 of sites of known ages have been used to estimate the ages of undated sites we present schmidt hammer rebound r values from 28 little ice age and younger 23 preboreal and 7 younger dryas glaciated surfaces in southern norway in order first to test rigorously the robustness of the instrument as a relative age dating tool despite being obtained from different surfaces moraines glaciofluvial deposits and bedrock and varied metamorphic lithologies the r value overall means and 95 confidence intervals for the little ice age preboreal and younger dryas age categories respectively 60 0 1 6 41 6 1 4 and 34 2 2 0 are statistically significantly different only two outlying sites in the two younger age categories have overlapping confidence intervals demonstrating remarkable robustness in differentiating early and late holocene surfaces the distinction between preboreal and younger dryas sites with terminal dates 2000 years apart is less clear but still statistically significant though possibly partly because of enhanced weathering conditions at the predominantly well vegetated younger dryas sites second we examine the feasibility and desirability of controlling non age related factors including some previously considered critical instrument wear operator bias initial rock surface texture which emerge either as less important than previously argued or as relatively unimportant together with others previously unreported e g long term changes in lichen soil snow and vegetation covers third we investigate the potential for calibrated age dating by applying exploratory linear rates of r value decline to selected combinations of sites the results suggest that error limits of ca 700 to 1600 years should be achievable over the holocene timescale this improved dating capability however will require adequate numbers of site means not only for each age category used to define these curves but also for each set of test surfaces of the same ages recommendations are made for a suitable sampling protocol for developing further the schmidt hammer as a calibrated age dating tool

holocene river activity analysing 14c dated fluvial and colluvial sediments from germany records of fluvial dynamics in response to long term changes of climate and land use impacts are rare therefore cumulative probability functions cpfs of 401 14c ages originating from german rivers and hillslopes were compiled to reconstruct phases of increased geomorphic activity and stability during the holocene an improved analytical method is suggested to normalise cpfs and eliminated the effects of wiggles of the calibration curve and the young age bias nine periods of activity are identified peaking at 7050 6250 5525 3690 2250 1350 820 325 bc and since 875 ad and are compared with climatic palaeohydrological and human impact proxy data until 2250 bc events of geomorphic activity are mainly coupled to wetter and or cooler climatic phases due to growing population and intensive agricultural activities during the bronze age the increased geomorphologic activity between 1300 and 820 bc cannot unequivocally be related to climate since 875 ad the growing population density is considered as the major external forcing differential geomorphic activity of hillslopes and floodplains suggest that the hillslope channel coupling during the holocene is mainly controlled by human impact with a strong increased coupling after 1500 bc

depositional character and preservation potential of coarse grained sediments deposited by flood events in hyper arid braided channels in the rift valley arava israel abstract four coarse grained braided channels undergoing rapid deposition in the hyper arid arava rift valley have been studied to determine the dynamics of strata deposition by monitored flood events and to ascertain the sedimentologic character of these event deposits the systems span granule sand to sandy gravel bed material having longitudinal bars with simultaneously increasing grains size slope and bed relief scour and fill were monitored along cross sections using scour chains and repeat surveys while event strata fill were described with reference to sediment calibre type of support grading thickness and location unlike many previous investigations of gravel sedimentology the source of information for this study involves not only stratigraphic description but also observation of the concomitant dynamics of the channel bed as expressed by the extent of event deposition the texture of the deposited sediment generally coarsens in sympathy with the surface bed texture of the studied channels the thickness of event deposited sediments increases as the magnitude of flow events increases the stratigraphic record is characterized by 1 sub parallel stratification 2 no grading 3 clast supported gravel infilled with sand granule matrices and 4 rapid sedimentation rates this character is hypothesized to mirror the elevated bedload fluxes in this hyper arid fluvial setting lacking densely vegetated banks the proximal braidplain of this arid environment often contains no extensive fine textured floodplain successions the depth of fill as well as the extent of strata obliteration increase with flood magnitude explaining the increased preservation potential of event strata with increase in flood magnitude it also explains why most event strata including large ones are only partially preserved

zonal assessment of environmental driven settlement abandonment in the trans tisza region central europe during the early phase of the little ice age abstract this investigation focuses on the transformation of the settlement pattern of a lowland landscape as a social response to the hydrological challenges emerging in the late 13th century c overture of the little ice age lia results of the applied zonal analysis suggested a strong spatial connection between the geomorphological conditions the agro ecological suitability good excellent medium and low and the stability or instability of settlement patterns the elevation means of archaeological sites in the deserted zones proved significantly lower than those in zones with permanent settlement pattern brunner munzel test p 0 01 n 377 additionally the late medieval 14th mid 16th centuries site group was situated on average significantly higher than the high medieval late 10th 13th centuries site group within the permanent zones brunner munzel test p 0 01 n 219 these outcomes statistically confirm that not only did low lying inhabited areas shrink significantly but they also displaced vertically in the first phase of the lia when analysing the relation of settlement pattern to soil conditions the proportion of areas with good excellent agro ecological suitability proved 1 5 2 times higher in the permanent zones than in the deserted and uninhabited settlement suitability zones using the linear model different regression coefficients appeared between the extension of the high and medium agro ecological suitability zones and the number of high and late medieval settlements the different coefficients in the studied two periods suggest that the issue of agroecological suitability in the high middle ages did not bear such importance as in the late middle ages the findings of the paper may contribute to answering the question why the relatively dense settlement pattern of the deserted zones was abandoned almost completely by the end of the 13th c in areas where flood proneness and weak agro ecological suitability both meant a serious risk for human communities finally we presumed that if hydro climatic changes increased water levels they must have changed the plant composition of the studied landscape as well chi squared test of macrofossil plant remains narchaeological site 55 ntaxon 330 shows that the second part of the 13th c saw the ratio of species from humid habitat types grow 7 81 df 1 p 0 02 comparison of the two studied processes indicates a broad synchronism between the shrinkage of inhabited areas and the increasing proportion of plants with humid environment tolerance during the second part of the 13th c the reconstructed transformations in the composition of plant remains and settlement structure signal not a mere transitional change but a longue duree structural transformation of the landscape

non destructive testing for the assessment of granite decay in heritage structures compared to quarry stone several types of granite found in two architectural heritage monuments were assessed with two non destructive portable techniques schmidt hammer rebound and ultrasound velocity vp similar assessments were conducted on the rock from which the granite was originally quarried for comparison the results obtained which revealed the existence of a direct correlation constitute a useful indication of decay particularly if the approximate dates of construction are known and conversely if they are not such stone assessments may provide a rough estimate of when the structure was built both of these convenient portable and non destructive techniques may be used as reliable indicators of the degree of stone decay

fluvial chronology in the east european plain over the last 20 ka and its palaeohydrological implications abstract a database containing 983 absolute ages of fluvial deposits was interpreted in palaeohydrological terms and 646 dates were found associated with 754 local palaeofluvial events geomorphic or sedimentological traces of changing fluvial activity combined probability density functions of high and low activity dates were used to detect time intervals of different palaeohydrological status after low fluvial activity during lgm two palaeohydrological epochs were designated extremely high activity in the end of mis 2 ca 18 11 7 ka before ce 2000 b2k and much lower activity in the holocene within the holocene two hierarchical levels of hydroclimatic variability were designated according to their duration and magnitude regional palaeohydrological phases centuries to few millennia and regional palaeofluvial episodes decades to few centuries tendency is rather clear of activity lowering in the first half and rise in the second half of the holocene extremes within the palaeohydrological phases were designated as 19 palaeofluvial episodes 7 high activity ha episodes 8 low activity stability la episodes and 4 contrast or complex ca episodes in most cases changes of fluvial activity were most likely induced by changing amounts of spring snowmelt runoff most distinct correlation of temperature and hydrological regimes was found in the late holocene high fluvial activity corresponded to cold climatic phases little ice age low activity to warm phases medieval climatic optimum current climate warming the suggested fluvial chronology was compared with independent hydroclimatic archives such as palaeosoils and lake levels correlation with soil formation alluviation epochs was found very close with some exceptions in the early holocene correspondence of fluvial activity to the caspian sea level changes is rather high in the second part of the holocene and is poor before 4 5 ka b2k which can be explained by insufficient data behind both types of reconstructions correlation of changes in fluvial activity within a west east transect over europe revealed relatively poor correlation in the early and mid holocene and much higher synchronism since 3 0 ka b2k which may indicate increasing role of westerlies in controlling european climates in the late holocene throughout the whole holocene changes of fluvial activity over eep were governed by natural climate forcing until the last few centuries when land use changes induced accelerated hillslope and gully erosion

scaling factors for the rates of production of cosmogenic nuclides for geometric shielding and attenuation at depth on sloped surfaces abstract the decrease in rates of production of cosmogenic nuclides occurs because of shielding of cosmic rays by mountains sloped surfaces and local rock formations that block them when a large part of the sky is blocked this correction is large and requires detailed model calculations this paper considers three geometries a rectangular obstruction a triangular obstruction and a sloped surface other geometries can be considered as a combination of these the results are presented in terms of formulas and graphs so that the reader can easily apply them to common field situations any use of cosmogenic nuclides in the study of geomorphic processes or forms must consider factors that introduce variations in the production of nuclides

multi phase dolomitization and recrystallization of middle triassic shallow marine peritidal carbonates from the mecsek mts sw hungary as inferred from petrography carbon oxygen strontium and clumped isotope data abstract shallow marine to peritidal carbonates of the triassic csukma formation in the mecsek mts of sw hungary are made up of dolomites limestones and dolomitic limestones that show evidence of a complex diagenetic history integration of petrographic conventional stable oxygen and carbon isotope clumped isotope and strontium isotope data with the paleogeography paleoclimate and burial history of the region revealed four major diagenetic stages stage 1 the peritidal carbonates were dolomitized penecontemporaneously during the middle triassic by refluxing evaporatively concentrated brines stage 2 increasing burial during the late triassic jurassic resulted in recrystallization of the kan dolomite member in an intermediate burial setting stage 3 during the early cretaceous seawater was drawn down and circulated through rift related faults causing renewed recrystallization of the kan dolomite member as well as dolomitization of the kozar limestone member and the underlying limestones in a deep burial setting but only in the vicinity of the faults stage 4 during the late cretaceous and cenozoic thrusting resulted in tectonic expulsion of basinal fluids and precipitation of multiple saddle dolomite cement phases near the faults the results of this study imply that the clumped isotope method integrated with other geochemical data can successfully be applied to identify the nature and potential sources of extra formational diagenetic fluids responsible for dolomitization and recrystallization this study provides conclusive evidence for multi phase dolomitization and dolomite recrystallization over several millions of years middle triassic through early cretaceous and several thousands of meters of burial in the csukma formation in sw hungary furthermore this study is the first to identify fault controlled dolomitization by circulating cretaceous seawater within triassic carbonates of central europe further supporting the viability of the interpretation of dolomitization by seawater initially drawn down and then geothermally circulated through faults in extensional basins

roman and early medieval habitation patterns in a delta landscape the link between settlement elevation and landscape dynamics settlement locations in delta landscapes change through time because of cultural and natural dynamics we assessed the impact of natural landscape dynamics on settlement location shifts for the rhine meuse delta in the netherlands during the roman and early medieval periods 12 bce 450 ce and 450 1050 ce respectively during this time interval major landscape and cultural changes occurred in this area with river avulsions and changes in flooding frequency coinciding with changing settlement patterns in the delta plain the relatively high and dry alluvial ridges of abandoned or active rivers were most favourable for habitation settlement location and elevation patterns were reconstructed in these landscape units using a high resolution elevation map of the alluvial ridges by integrating high resolution palaeo environmental and archaeological datasets for this period we were able to spatially analyse the trends and to assess the effect of environmental changes on habitation results show that settlements progressively shifted towards higher areas between 250 and 750 ce on average by 20 cm over this period deltawide which was coeval with an increased frequency of severe rhine floods the observed spatial differences demonstrate that this trend is most notable in the least elevated segments of the study area in areas where new large river branches developed settlements show a strong shift towards higher elevated parts of the landscape or even became completely abandoned the river probably caused floods to be more frequent and more severe in these areas despite the clear link between changing settlement positions and floods during the studied time interval floods do not seem to have caused long term abandonment of major parts of the study area

comparative analysis of coatings on granitic substrates from urban and natural settings nw spain abstract rock coatings are frequent on natural rock outcrops and even more on stone surfaces of historical buildings and monuments they are interesting as some of them have a protective effect against erosion in the last 30 years research on rock coatings has been performed separately on either buildings or natural outcrops this paper studies and compares thin coatings found on granitic rock surfaces of historical buildings with coatings found on natural granite outcrops in a same climatic area nw spain by analysing their surface and cross sections as rock surfaces of buildings have known age they can be used to assess rates of weathering and coating growth this is the first comparative study of formation of coatings on natural and built surfaces in the same region both endogenous rock characteristics and exogenous factors climatic conditions air pollution that could affect the coatings formation are considered to assess the origin and formation of coatings x ray diffraction xrd and x ray fluorescence xrf analyses of the underlying rocks xrd analyses of the coatings and scanning electron microscopy sem observations of surface and cross sections of the coatings performing energy dispersive spectrometry eds and x ray maps were carried out to establish their composition fieldwork and results indicate that natural outcrops are widely covered by biological coatings or coatings formed due to rock weathering while coatings found on rock ashlars are highly variable with air pollution other building materials organic droppings and micro environmental factors contributing to coatings on rock ashlars in a more significant way than substrate characteristics and exposure time

landform transformation and long term sediment budget for a chernozem dominated lowland agricultural catchment abstract the loess hilly lands of the south west foreland of the west carpathians are characterized by favorable climatic conditions smooth topography fertile soils and a long settlement history for the first time we document changes to human induced landforms in a small zero order dry valley 0 28 km2 with calcic chernozem soils and develop a long term sediment budget the original surface was reconstructed based on interpreting records of erosion and deposition from 185 soil cores and six valley cross sections the topography inherited from the pleistocene was transformed through lowering of hillslope ridges and convexities along with infilling of shallow depressions within the original valley bottom on convex convex landforms had an average net erosion of 0 32 0 01 m while average net accumulation in the valley bottom was estimated at 0 20 0 01 m the correlation between change in soil profile depth with profile curvature 0 51 p

application of schmidt hammer relative age dating to late pleistocene moraines and rock glaciers in the western tatra mountains slovakia abstract in order to evaluate the potential of the schmidt hammer for relative age dating of late pleistocene moraines and rock glaciers rebound r values were collected at 38 sites in two formerly glaciated valleys in the western tatras in northern slovakia a large statistical population of measurements obtained from moraine and rock glacier surfaces was used to analyze the variability of mean r values in the same lithology and overall southern valley exposition four separate sets of glacial periglacial morphosystems are present at different positions in the western tatras starting from valley outlets to the highest cirques which represent successive phases of deglaciation r value means and 95 confidence intervals for selected last glacial maximum lgm and late glacial lg 1 lg 2 and lg 3 stages respectively 40 1 1 1 46 0 5 53 5 1 0 and 60 5 0 3 are significantly statistically different and values for each age category are comparable for the two analyzed valleys the results of weathering indexes used in conjunction with geomorphological relationships were taken together to reconstruct the pattern of deglaciation on southern tatra slopes it is stated that the schmidt hammer technique may be successfully used as a relative age dating tool for late pleistocene glacial and periglacial deposits and with this method it is possible to differentiate between late glacial moraines and rock glacier systems of different age

dedolomitization and calcite cementation in the middle devonian winnipegosis formation in central saskatchewan canada limestone consisting of finely to medium crystalline calcite mosaics is present in the upper part of the winnipegosis formation on the east central margin of the elk point basin where the overlying prairie evaporite deposits have been removed this type of crystalline limestone is interpreted as dedolomite based on petrographic observations the 18o and 13c values of the winnipegosis dedolomite vary from 12 8 to 11 9 vpdb vienna pee dee belemnite and from 0 5 to 1 7 vpdb respectively both values are significantly lower than those for the corresponding dolomite the 87sr 86sr ratios of the dedolomite are significantly higher between 0 7082 and 0 7087 the spatial distribution and geochemical data of the winnipegosis dedolomite suggest that dedolomitization was related to an influx of fresh groundwater and dissolution of the prairie evaporite anhydrite during the latest mississippian to the early cretaceous when the basin was subjected to uplift and erosion the winnipegosis dedolomite displays a series of replacement fabrics showing progressive calcitization of dolomite including the occurrence of dedolomite restricted along fractures and adjacent areas dolomite patches floating in the dedolomite masses and massive dedolomite with sparsely scattered dolomite relicts however the characteristic fabrics resulting from dedolomitization documented in the literature have not been observed in the winnipegosis dedolomite coarsely to very coarsely crystalline subhedral to euhedral calcite cement is restricted in the dedolomite the petrographic features isotopic compositions and homogenization temperatures coupled with the burial history of the winnipegosis formation constrain the precipitation of the calcite cement from a mixing of basinal brines and fresh groundwater during late cretaceous to neogene time the more negative c isotopic signatures of the calcite cement 5 3 to 2 3 vpdb probably reflect a hydrocarbon derived carbon

origin of disconformity dedolomite in the martin formation late devonian northern arizona abstract calcitized dolomite dedolomite occurs along a prominent disconformity in the upper martin dolomite of north central arizona petrography stable isotopes and field associations were used in an effort to constrain the origin and timing of the dedolomite 18 o 16 o and 13 c 12 c ratios of the dedolomite show significant depletions relative to unaltered dolomite above and below the disconformity this depletion trend and dedolomitization are interpreted to have resulted from a subaerial exposure and an influx of 18 o depleted meteoric water or b descending groundwater from paleoaquifers in the lower pennsylvanian sedimentary features consistent with a subaerial exposure include detrital filled desiccation cracks and an accumulation of iron rich residual clays features suggestive of dedolomitization by paleogroundwater include calcite replaced evaporite nodules and the great volume of water inferred to have been associated with extensive continental lower pennsylvanian karstification of overlying younger carbonate units

influence of relief characteristics and landscape connectivity on sediment redistribution in small agricultural catchments in the forest steppe landscape zone of the russian plain within european russia abstract sheet rill and gully erosion occurring in the snowmelt period march april and rainfall season may september is the main factor of soil degradation and mobilized hillslope sediment redistribution within cultivated lands of the russian plain the evaluation of sediment redistribution for the period since 1986 within catchment sediment cascades was done based on an integrated approach for some representative dry valley catchments located in the western the plava river basin tula oblast russian federation and eastern the temeva rechka creek catchment the myosha river basin republic of tatarstan russian federation sectors of the forest steppe landscape zone of the russian plain all the catchments studied are characterized by a high proportion within the range of 60 80 of cultivated lands the modified version of the universal soil loss equation usle the russian state hydrological institute s erosion model and the landsoil erosion model were applied to calculate soil losses within the cultivated lands the morphological classification of interfluve slopes and hollow slope catchments in combination with the sediment delivery ratio sdr assessment for slopes and hollow slope catchments of different configuration were used to assess sediment transfer from the cultivated lands the chernobyl derived 137cs isotope was applied as a chronomarker for sediment dating in different sediment sinks located along pathways from cultivated slopes to river valley bottoms we found that the morphological features of the dry valley catchments including a pattern of the dry valleys of different hortonian orders dry valley and hollow density dry valley incision depth and proportion of slopes and hollow slope catchments of different configurations are the main parameters that determined a proportional input of the different sediment sinks to the sediment interception along the pathways from the cultivated slopes to the river valley bottoms the land use cover features are mostly responsible for the pattern of buffer zones within the interfluve parts of the catchments the quantitative assessment of the sediment budget allowed us to conclude that the mean sdr coefficients for the dry valley catchments of second third and fourth hortonian orders are 0 56 0 33 and 0 07 respectively the extrapolation of the study results of sediment redistribution evaluation obtained from the studied catchments located within the plava river basin to the entire basin of the river also allowed us to evaluate the mean value of hillslope to river valley bottom sdr 0 27

assessing the age weathering correspondence of cosmogenic 21ne dated pleistocene surfaces by the schmidt hammer the schmidt hammer sh method is used to quantify the rock weathering degree and has been proposed as a relative dating tool terrestrial cosmogenic nuclide tcn methods provide absolute exposure ages for erosive surfaces few works combine both methods for surfaces older than the holocene we compare data obtained by both methods for c 150 ka bp glacial and fluvial erosive granite surfaces from northwest spain rebound values r have been firstly compared with the rock density to assess the correlation with the rock strength independently from influence of factors such as wetness and roughness in the r values for erosive glacial surfaces older than 100 ka r values are confined in a narrow range with no differences within errors stepped fluvial surfaces of 700 m to 70 m above present sea level show an inverse correspondence between tcn ages and r values although no age predictions can be done on the basis of the r values thus age inferences exclusively based on r values may not be realistic but sh studies could be a useful tool for selecting surfaces for tcn dating copyright 2009 john wiley sons ltd

techniques for measuring rock weathering application to a dated fan segment sequence in southern tunisia there are a number of techniques for estimating the amount of weathering a clast has undergone these usually have the objective of establishing an ordinal chronology of geomorphological surfaces or investigation of site specific conditions affecting weathering rates three such techniques are applied to a dated sequence of alluvial fan segments in southern tunisia two of these techniques depend on measuring surface roughness the micro roughness meter and a displacement approach and one uses the structural weakening of the rock fabric schmidt hammer the micro roughness meter enables calculation of standard deviation of surface height variation root mean square roughness and surface autocorrelation function of these techniques schmidt hammer rebound values standard deviation root mean square roughness and the displacement technique show systematic changes on the three fan segments which are statistically significant at the 0 05 level however the amount of variance in all datasets is very large indicating the need for caution in application of these techniques for relative dating 1998 john wiley sons ltd

events episodes and phases signal from noise in flood sediment archives major floods have increased in frequency in many parts of the world and this is often attributed to anthropogenic climate change because of the short length of most gauged records 50 yr it is unclear whether these events represent a short term anomaly or a shift to a prolonged flood rich period in this paper we use event scale paleoflood records from upland and lowland floodplains to demonstrate the relationship between individual flood events clusters of events in multiyear episodes and multidecadal to centennial scale flood rich phases catchment and regional scale data show that individual events and episodes generally fall within extended flood rich phases controlled by climate furthermore contrary to recent suggestions that environmental signals may be rendered incomplete in fluvial systems by autogenic processes from a multidecadal and longer perspective it is clear that floodplain environments can register and preserve a useful multiscale hydromorphic signal of climate change

erosion and sedimentation on the russian plain ii the history of erosion and sedimentation during the period of intensive agriculture the processes of sheet rill and gully erosion on the slopes of the russian plain are controlled by the same factors as elsewhere cover erodibility erosivity and landform the combination of land use history and variations in these bio physical factors produced a history of erosion that is unique to this area the most eroded soils occur in the non black earth area especially where there are soddy podzolic soils over the entire russian plain 99 109 m3 of soil have been lost from the slopes since ad 1696 on the arable land a layer 40 cm has been eroded about 2 106 gullies more than 300 m in length have formed during the last 300 years mobilizing about 4 109 m3 of sediment about 97 of this vast amount of soil has been redeposited on the plain rather than transported to the oceans the effect of the sediment on stream channels has been greatest in the headwaters where large numbers of low order channels have been completely infilled up to 5 6 m of sediment has accumulated in some of these small valleys copyright 2003 john wiley sons ltd

the schmidt hammer as a holocene calibrated age dating technique testing the form of the r value age relationship and defining the predicted age errors most recent developments of schmidt hammer exposure age dating shd as a calibrated age dating tool have been limited by the use of locations at two age control points this has necessitated 1 making assumptions about a linear r value age relationship and 2 basing predictions of age errors only on r value variance at the two age control points this paper analyses 9900 r values obtained from multiple age control points on a sequence of glacio isostatically raised shorelines with well constrained ages skuleskogen high coast world heritage site and environs gulf of bothnia northern sweden ranging from modern to 10 5 ka in age the sampling design involved 30 measurements on granite beach boulders from 30 sites at 11 age control points the r value age relationship is best described by a linear function ordinary least squares ols with an r 2 of 0 89 p 0 0001 predicted age errors are calculated using two approaches 1 ols regression which takes account of the uncertainties associated with the regression line and the age control points and 2 weighted total least squares wtls regression which in addition takes account of possible shoreline age errors and the heteroscedasticity of r value residuals with increasing age with both approaches 95 predicted age errors are relatively modest 355 455 years and 300 515 years respectively with larger r value variance and hence uncertainty for older surfaces and the possibility of further improvement from a more selective field sampling scheme that differentiates between age related and non age related rock surface variability our results also indicate that for certain lithologies and weathering environments it is possible to construct reliable calibrated age curves from relatively few age control points

authigenic fluorite in dolomitic rocks of the floridan aquifer fluorite in eocene carbonate mudstone of florida is reported for the first time fluorite occurs within primary gypsum nodules at a depth of 235 240 m below the surface water chemistry indicates undersaturation for gypsum and fluorite and their survival is attributed to a lack of groundwater circulation fluorite probably formed penecontemporaneously with gypsum in a sabkha environment from seawater concentrated brine an additional source of fluoride may have been fluvial transport of salts weathered from appalachian volcanic rocks

the geochemistry of carbonate diagenesis the past present and future stable carbon and oxygen isotopes 18o and 13c values and trace elements have been applied to the study of diagenesis of carbonate rocks for over 50 years as valuable as these insights have been many problems regarding the interpretation of geochemical signals within mature rocks remain for example while the 18o values of carbonate rocks are dependent both upon the temperature and the 18o value of the fluid and additional information including trace element composition aids in interpreting such signals direct evidence of either the temperature or the composition of the fluids is required such information can be obtained by analysing the 18o value of any fluid inclusions or by measuring the temperature using a method such as the clumped isotope technique such data speak directly to a large number of problems in interpreting the oxygen isotope record including the well known tendency for 18o values of carbonate rocks to decrease with increasing age unlike the 18o 13c values of carbonates are considered to be less influenced by diagenesis and more a reflection of primary changes in the global carbon cycle through time however many studies have not sufficiently emphasized the effects of diagenesis and other post depositional influences on the eventual carbon isotopic composition of the rock with the classic paradigm that the present is the key to the past being frequently ignored finally many additional proxies are poised to contribute to the interpretation of carbonate diagenesis although the study of carbonate diagenesis is at an exciting point with an explosion of new proxies and methods care should be taken to understand both old and new proxies before applying them to the ancient record

a holocene alluvial sequence in the lower tyne valley northern britain a record of river response to environmental change palaeoenvironmental investigations have been made of late quaternary sediments infilling the lower tyne valley at scotswood newcastle upon tyne 18 km upstream from the mouth of the river attention has focused on the holocene alluvial sedimentary sequence using sedimentological geochemical and palynological analyses holocene valley floor development from c 7500 bp has been largely dominated by a tendency towards river aggradation with some limited lateral and vertical reworking of sediments four alluvial fills have been identified and dated to 1 c 7500 4800 bp 2 from c 2590 bp up to the early first millennium ad and possibly as late as medieval times 3 between the medieval period and the early seventeenth century and 4 between the seventeenth and nineteenth centuries episodes of incision are dated to c 4800 2590 bp and to the period following the early seventeenth century marked variations in the rates and nature of sedimentation and erosion appear to coincide with rising post glacial

isotope signatures associated with early meteoric diagenesis the environments in which carbonate diagenesis proceeds have been documented in previous studies of holocene and late pleistocene sediments and limestones on barbados west indies variations in the carbon and oxygen isotopic composition of limestones produced during early freshwater diagenesis have been observed in this study to occur in specific patterns six potentially useful patterns emerge when one views stable isotope data within a stratigraphic framework 1 the subaerial exposure surface is characterized by strongly 12c enriched limestones 13c compositions of underlying limestones grow progressively heavier with increasing depth 2 the subaerial exposure surface may also be marked by slight 18o enrichment 3 an abrupt shift in 18o values may differentiate sediments above the exposure surface from those below 4 sediments altered in the marine meteoric mixing zone may be characterized by positive covariance between their 18o and 13c compositions 5 the vadose phreatic boundary may be marked by a sharp increase in 13c values in the seaward portions of a fresh groundwater system and 6 samples contemporaneously altered in a single fresh groundwater system within an areally restricted region should display a narrow range of 18o and a wide range of 13c compositions analysis of samples from five palaeozoic and mesozoic formations which contained petrographic evidence of early freshwater diagenesis showed that isotope patterns similar to those observed in barbados limestones have been preserved in rocks as old as mississippian these isotope patterns could prove to be useful for identifying diagenetically induced porosity trends in carbonate rocks they might be used to identify limestones diagenetically altered in meteoric environments to identify mixing zone cements and dolomites and to trace the regional and vertical distributions of early meteoric groundwater systems in ancient carbonate formations

the origin and evolution of saline formation water lower cretaceous carbonates south central texas u s a abstract land l s and prezbindowski d r 1981 the origin and evolution of saline formation water lower cretaceous carbonates south central texas u s a in w back and r letolle guest editors symposium on geochemistry of groundwater 26th international geological congress j hydrol 54 51ndash 74 systematic chemical variation exists in formation water collected from a dip section through lower cretaceous rocks of south central texas chemical variation can be explained by an interactive water rock diagenetic model the cyclic lower cretaceous shelf carbonates of the edwards group dip into the gulf of mexico coast geosyncline and can be considered to a first approximation as part of a complex aquifer contained by paleozoic basement beneath and by relatively impermeable upper cretaceous clay and chalk above the hydrodynamic character of this carbonate system is strongly controlled by major fault systems major fault systems serve as pathways for vertical movement of basinal brines into the lower cretaceous section formation water movement in this sytem has strong upfault and updip components the parent na ca cl brine originates deep in the gulf of mexico basin at temperatures between 200 and 250 c by the reaction halite detrital plagioclase quartz water albite brine other dissolved components originate by reaction of the fluid with the sedimentary phases k feldspar calcite dolomite anhydrite celestite barite and fluorite significant quantities of pb zn and fe have been mobilized as well as the brine moves updip out of the overpressured deep gulf of mexico basin and encounters limestones of the stuart city reef trend the buried platform margin small amounts of galena precipitate in late fractures continuing to rise upfault and updip the brine becomes progressively diluted on encountering significant quantities of dolomite in the backreef facies the ca rich brine causes dedolomitization although thermochemical consideration suggests that small amounts of several authigenic phases should precipitate most have yet to be found minor amounts of several kinds of calcite spar are present however as the brine evolves by dilution and by cooling no systematic changes in any cation cl ratio occur except for regular updip gain in mg as a result of progressive dedolomitization the formation water highly diluted by meteoric water eventually discharges along faults as hot mineral water

the history of soil erosion and fluvial deposits in small catchments of central europe deciphering the long term interaction between humans and the environment a review abstract during the last few decades many case studies focused on the dynamics of fluvial systems in response to hillslope erosion land use impact and climate changes this paper will review the current state of knowledge of the dynamics of past soil erosion and gullying in small catchments

inside out dolomite abstract inside out dolomite crystals are unusual because their cores are younger than their encasing cortices in the cayman formation middle miocene of grand cayman they developed diagenetically from zoned dolomite crystals that have cores formed of high ca calcian dolomite hcd 55 mol caco3 and outer cortical zones formed of low ca calcian dolomite lcd 3 or oscillatory zoned lcd hcd the cores of these crystals labeled as type i have a euhedral rhombic outline with no embayments or angular reentrants and commonly contain calcite inclusions and or micropores hollow dolomite crystals evolved from these crystals as preferential dissolution removed all or part of the hcd core later calcite or dolomite cement was precipitated inside the hollow crystals the former produced dolomite crystals with a calcitic core i e dedolomite whereas the latter produced inside out dolomite crystals that have a dolomite core lcd or hcd encased by a dolomite cortex the cores of the inside out dolomite crystals labeled as type ii have an irregular outline characterized by angular reentrants and or embayments micropores that are usually larger than those in the type i cores but few calcite inclusions the cortical zones have a euhedral rhombic motif irrespective of the type of core development of insideout dolomite crystals may significantly alter the average ca of the dolostones as hcd is lost to dissolution and lcd or hcd cement is precipitated in its place the 18o may also change inasmuch as it is thought to covary with ca in some tertiary dolostones the genesis of inside out dolomite crystal may offer an alternative explanation for the textures e g clotted cathodoluminescence patterns in some ancient dolomite crystals that have been attributed to replacement and or recrystallization

erosion rates of alpine bedrock summit surfaces deduced from in situ 10be and 26al we have measured the concentration of in situ produced cosmogenic 10be and 26al from bare bedrock surfaces on summit flats in four western u s mountain ranges the maximum mean bare bedrock erosion rate from these alpine environments is 7 6 3 9 m my 1 individual measurements vary between 2 and 19 m my 1 these erosion rates are similar to previous cosmogenic radionuclide crn erosion rates measured in other environments except for those from extremely arid regions this indicates that bare bedrock is not weathered into transportable material more rapidly in alpine environments than in other environments even though frost weathering should be intense in these areas our crn deduced point measurements of bedrock erosion are slower than typical basin averaged denudation rates 50 m my 1 if our measured crn erosion rates are accurate indicators of the rate at which summit flats are lowered by erosion then relief in the mountain ranges examined here is probably increasing we develop a model of outcrop erosion to investigate the magnitude of errors associated with applying the steady state erosion model to episodically eroding outcrops our simulations show that interpreting measurements with the steady state erosion model can yield erosion rates which are either greater or less than the actual long term mean erosion rate while errors resulting from episodic erosion are potentially greater than both measurement and production rate errors for single samples the mean value of many steady state erosion rate measurements provides a much better estimate of the long term erosion rate

gully erosion impacts factors and control gully erosion attracts increasing attention from scientists as reflected by two recent international meetings poesen and valentin eds catena 50 2 4 87 564 li et al 2004 gully erosion under global change sichuan science technology press chengu china 354 pp this growing interest is associated with the increasing concern over off site impacts caused by soil erosion at larger spatial scales than the cultivated plots the objective of this paper is to review recent studies on impacts factors and control of gully erosion and update the review on dgully erosion and environmental change importance and research needst poesen et al 2003 catena 50 2 4 91 134 for the farmers the development of gullies leads to a loss of crop yields and available land as well as an increase of workload i e labour necessary to cultivate the land gullies can also change the mosaic patterns between fallow and cultivated fields enhancing hillslope erosion in a feedback loop in addition gullies tend to enhance drainage and accelerate aridification processes in the semi arid zones fingerprinting the origin of sediments within catchments to determine the relative contributions of potential sediment sources has become essential to identify sources of potential pollution and to develop management strategies to combat soil erosion in this respect tracers such as carbon nitrogen the nuclear bomb derived radionuclide 137 cs magnetics and the strontium isotopic ratio are increasingly used to fingerprint sediment recent studies conducted in australia china ethiopia and usa showed that the major part of the sediment in reservoirs might have come from gully erosion gullies not only occur in marly badlands and mountainous or hilly regions but also more globally in soils subjected to soil crusting such as loess european belt chinese loess plateau north america and sandy soils sahelian zone north east thailand or in soils prone to piping and tunnelling such as dispersive soils most of the time the gullying processes are triggered by

calcitization dedolomitization of jurassic dolostones lebanon results from petrographic and sequential geochemical analyses calcitized jurassic dolostones from central mount lebanon kesrouane formation are discussed utilizing petrographic mineralogical and geochemical data in particular two sequential extraction methods for both major trace elements and stable isotope analyses provide results that support and refine conventional bulk analyses data the new data demonstrate that the major dedolomitization phase of the investigated jurassic carbonates occurred as a result of the migration of karst related meteoric waters characterized by soil derived carbon and estimated 18ov smow composition between 7 2 and 3 4 into previously dolomitized horizons within the limestone rock during the final uplift and emergence of mount lebanon after palaeogene time the study demonstrates that in this case the mechanisms of dedolomitization and their resulting fabrics are controlled primarily by the texture of the original dolomite rock pervasively dolomitized rocks where the micritic matrix is entirely dolomitized show calcitization mainly through dissolution precipitation by contrast the rock textures that still include a considerable amount of limey micritic matrix spared from dolomitization are more prone to mole per mole and mimic replacement of the dolomite crystals by calcite

nature and origin of collapse breccias in the zechstein of ne england local observations with cross border petroleum exploration and production significance across the north sea

subglacial recharge into the western canada sedimentary basin impact of pleistocene glaciation on basin hydrodynamics brine springs discharging from devonian carbonates of the western canada sedimentary basin have distinct water chemistry from brines in laterally equivalent units deeper in the basin stable isotope data suggest that the brine springs originated as pleistocene meltwater these waters are interpreted to originate as an influx of subglacial meltwater related to a reversal of the basin scale flow system caused by the overriding ice sheet esker distribution shows a notable relationship between shield and sedimentary rocks an integrated sedimentary basin ice sheet model supports the interpretation that high permeability carbonate units acted as preferential subglacial drains that in turn affected esker development the fluid flow history of the western canada sedimentary basin is characterized by back and forth movement through geological time in response to changing boundary conditions modern day flow systems may not then be indicative of historic movement of economic fluids through the basin

scaling factors for production rates of in situ produced cosmogenic nuclides a critical reevaluation abstract new scaling factors are presented describing the altitude and latitudinal dependence of production rates for in situ produced cosmogenic nuclides the new factors incorporate the influence of the non dipole contributions to the geomagnetic field on the cosmic ray flux the currently used scaling factors of lal earth planet sci lett 104 1991 424 439 are based on the assumption of a dipole field the overall strategy used in deriving the new scaling factors is however very similar to that of lal and relies on the same and or similar nuclear data in this reevaluation data are only used if the effective geomagnetic parameters inclination horizontal field strength can be reconstructed for the time of measurement the absorption free pathlengths for cosmic rays selected for this study are based on observational data at altitudes relevant for exposure age dating sea level to 7000 m at sea level and latitudes between 20 and 40 the new factors are up to 18 lower and at high altitudes more than 30 higher than those of lal in addition to accounting for the influence of the effective geomagnetic field and providing more applicable estimates of the new factors also allow for correction for the significant deviations from the standard pressure altitude relationship that exist in the atmosphere 10

oxygen isotope evolution of biogenic calcite and apatite during the middle and late devonian oxygen isotope ratios of well preserved brachiopod calcite and conodont apatite were used to reconstruct the palaeotemperature history of the middle and late devonian by assuming an oxygen isotopic composition of 1 v smow for devonian seawater the oxygen isotope values of eifelian and early givetian brachiopods and conodonts give average palaeotemperatures ranging from 22 to 25 c late givetian and frasnian palaeotemperatures calculated from 18o values of conodont apatite are close to 25 c in the early frasnian and increase to 32 c in the latest frasnian and early famennian oxygen isotope ratios of late givetian and frasnian brachiopods are significantly lower than equilibrium values calculated from conodont apatite 18o values and give unrealistically warm temperatures ranging from 30 to 40 c diagenetic recrystallization of shell calcite different habitats of conodonts and brachiopods as well as non equilibrium fractionation processes during the precipitation of brachiopod calcite cannot explain the 18o depletion of brachiopod calcite moreover the 18o depletion of brachiopod calcite with respect to equilibrium 18o values calculated from conodont apatite is too large to be explained by a change in seawater ph that might have influenced the oxygen isotopic composition of brachiopod calcite the realistic palaeotemperatures derived from 18o apatite may suggest that biogenic apatite records the oxygen isotopic composition and palaeotemperature of palaeozoic oceans more faithfully than brachiopod calcite and do not support the hypothesis that the 18o 16o ratio of devonian seawater was significantly different from that of the modern ocean

dating fluvial terraces with and profiles application to the wind river wyoming abstract fluvial strath terraces provide a record of river incision and the timing of climatic perturbations to the fluvial system dating depositional surfaces like terraces that are older than the range of 14 c however is difficult we employ a cosmogenic radionuclide crn profile technique that addresses a major problem of crn dating on such surfaces nuclide inheritance by measuring 10 be and 26 al profiles we constrain the exposure age and the mean crn inheritance for the deposit the crn profile also yields a self check on the assumptions underlying the method we report our attempts to date terraces along the wind river wy like many sequences of western north american fluvial terraces these are inferred to reflect oscillation between glacial and interglacial conditions in the headwaters previous dating of some of these terraces and the associated terraces and glacial deposits makes this a unique location to compare dating methods dates from five sites along the bull lake glacial correlative terrace wr 3 are 118 125 ka which agrees with dates on bull lake age moraines and independent age estimates on the terrace and is consistent with the model of terrace glacial relationship crn inheritance is significant and highly variable requiring it be considered despite the additional sampling complexity assuming all inheritance in wr 3 deposits arises during exhumation in the headwaters we obtain minimum mean rates of exhumation of 13 130 m my for the source rocks alternatively assuming the crns are inherited during clast transport the time of fluvial transport from source to terrace is 10 ka it increases downstream and is lower for sand than cobbles the crn ages for older terraces wr 7 300 ka and wr 15 510 ka are lower by 50 than previous estimates based on tephrochronology the most plausible explanation is eolian deflation of a once thicker loess cover on the terrace surfaces mean thicknesses of loess of 0 5 1 5 m are required to reconcile these concentrations of crn with the previous estimates of age difficulty in dating the older terraces emphasizes that geologic caution independent estimates of age and multiple sample sites should still be part of dating depositional surfaces with crns even when employing the inheritance correction technique

the use of the schmidt hammer and equotip for rock hardness assessment in geomorphology and heritage science a comparative analysis rapid field based measurements of rock hardness are of use in investigating many geomorphological and heritage science problems several different methods are now available for taking such measurements but little work has been done to assess their comparability and strengths and weaknesses we review here the capabilities of two types of schmidt hammer classic n type and silver schmidt bl type alongside two types of equotip standard type d and piccolo for investigating rock hardness in relation to rock weathering on various types of sandstone and limestone as well as basalt and dolerite whilst the two schmidt hammers and the two equotips show comparable results when tested at 15 individual sites interesting differences are found between the equotip and schmidt hammer values which may reveal information about the nature of weathering on different surfaces operator variance is shown to be an issue in particular for the equotip devices which also exhibit higher variability in measurements and necessitate larger sample sizes carborundum pre treatment also has varying effects on the data collected depending on the nature of the surface studied the equotip devices are shown to be particularly useful on smaller blocks and in situations where edge effects may affect schmidt hammer readings we conclude that whilst each device contributes to geomorphological research they do not necessarily produce comparable information indeed using schmidt hammer and equotip in combination and looking at any differences in results may provide invaluable insights into the structure of the near surface zones and the nature of weathering processes copyright 2010 john wiley sons ltd

schmidt hammer exposure age dating shd of late quaternary fluvial terraces in new zealand schmidt hammer sh r values are reported for surface clasts from numerically dated holocene and pleistocene fluvial terraces in the south island of new zealand the r values are combined with previously obtained weathering rind radiocarbon terrestrial cosmogenic nuclide and luminescence terrace ages to derive sh r value chronofunctions for greywacke clasts from four distinct locations our results show that different weathering rates affect the form of the sh r value versus age curve however a fundamental dependency between the two remains constant over timescales ranging from 102 to 105 years power law scaling constants suggest changes in clast weathering rates are primarily affected by climatic precipitation and temperature and sedimentologic variables source terrane petrology age uncertainties of 22 of the surface age suggest that schmidt hammer exposure age dating shd is a reliable calibrated age dating technique for fluvial terraces copyright 2013 john wiley sons ltd

mass spectrometric identification of cosmic ray produced neon in terrestrial rocks with multiple neon components studies of cosmic ray produced nuclides in terrestrial rocks are expected to provide important geomorphological and glaciological information such as surface exposure ages erosion rates and extent of glacial cover in the case of the stable nuclide21ne the cosmic ray produced component may represent but one of several components and a component resolution based on three isotope correlations is essential we developed analytical techniques which permit accurate corrections for all interfering ions we show for our modified nier source that corrections for doubly charged species based on constant charge state ratios are not satisfactory the improved techniques permit isotopic studies of 106 atoms of21ne the spallation ratio 22ne 21ne c from si was calibrated using a quartz separate from an allan hills sandstone and yields a value of1 243 0 022 this ratio is expected to be essentially constant for terrestrial quartz samples and should be useful in component resolutions the stepwise release of ne at increasing temperatures shows that cosmic ray produced ne is released from quartz at rather low temperatures this permits an estimate of the activation energy for ne diffusion in quartz 90 10 kj mol

glacier variations in breheimen southern norway dating little ice age moraine sequences at seven low altitude glaciers moraine sequences in front of seven relatively low altitude glaciers in the breheimen region of central southern norway are described and dated using a multi proxy approach to moraine stratigraphy lichenometric dating based on the rhizocarpon subgenus is used to construct a composite moraine chronology which indicates eight phases of synchronous moraine formation ad 1793 1799 1807 1813 1845 1852 1859 1862 1879 1885 1897 1898 1906 1908 and 1931 1933 although the existence of a few cases of older moraines possibly dating from earlier in the eighteenth or late in the seventeenth centuries cannot be ruled out by lichenometry schmidt hammer r values from boulders on outermost moraine ridges suggest an absence of holocene moraines older than the little ice age twenty three radiocarbon dates from buried soils and peat associated with outermost moraines at three glaciers tverreggibreen storegrovbreen and greinbreen also indicate that the little ice age glacier maximum was the neoglacial maximum at most if not all glaciers several maximum age estimates for the little ice age glacier maximum range between the fifteenth and seventeenth centuries with the youngest from a buried soil being ad 1693 a pre little ice age maximum cannot be ruled out at greinbreen however where the age of buried peat suggests the outermost moraine dates from ad 981 1399 at variance with the lichenometric evidence glaciofluvial stratigraphy at tverreggibreen provides evidence for minor glacier advances about ad 655 963 and ad 1277 1396 respectively copyright 2003 john wiley sons ltd

karstification without carbonic acid bedrock dissolution by gypsum driven dedolomitization aggressive karstification can take place where dolomite and gypsum are in contact with the same aquifer gypsum dissolution drives the precipitation of calcite thus consuming carbonate ions released by dolomite lake banyoles in northeastern spain is a karst lake supplied by sublacustrine springs and karstic collapse is occurring in the immediate vicinity of the lake lake water is dominated by mg ca and so 4 hco 3 and is supersaturated with calcite that is actively accumulating in lake sediments water chemistry sulfur isotope composition local stratigraphy and mass balance modelling suggest that the primary karst forming process at at lake banyoles is dedolomitization of basement rocks driven by gypsum dissolution karstification takes place along the subsurface contact between the gypsiferous beuda formation and the dolomitic perafita formation this process is here recognized for the first time to cause karstification on a large scale this is significant because it proceeds without the addition of soil generated carbonic acid gypsum driven dedolomitization may be responsible for other karstic systems heretofore attributed to soil generated carbonic acid