multi proxy evidence of holocene climate variability in volhynia upland se poland recorded in spring fed fen deposits from the komarow site radiocarbon dated spring fed fen deposits from the komarow site volhynia upland se poland with its multi proxy data macrofossils molluscs geochemistry pollen stable isotopes of oxygen and c

isotope geochemistry of fluid inclusions in permian halite with implications for the isotopic history of ocean water and the origin of saline formation waters abstract d and 18o values have been determined for fluid inclusions in 45 samples of permian halite the inclusions are enriched in 18o relative to the meteoric water line but are depleted in d relative to ocean water inclusions with the more positive values coincide with the isotopic composition expected for evaporating sea water which follows a hooked trajectory on a d 18o diagram inclusions with more negative values may represent more highly evaporated sea water but probably reflect synsedimentary or diagenetic mixing of meteoric water with evaporite brines the isotope systematics in these inclusions are sufficiently similar to those of a modern evaporite pan to indicate that permian sea water was isotopically similar to modern sea water connate evaporite brines can have negative values because of the probable hooked isotope trajectory of evaporating sea water and or synsedimentary mixing of evaporite brines with meteoric waters subsurface formation waters composed of mixtures of remnant primary evaporite brines and later meteoric waters may be more common than previous isotopic evidence has suggested

age and sr isotopic signature of the catoctin volcanic province implications for subcrustal mantle evolution variations in chemical and sr isotopic signatures of a series of basaltic flows have been correlated with newly mapped stratigraphic sections in the upper precambrian catoctin flood basalts in the central appalachians element mobility through fluid interaction is commonly observed in flows with a well developed fabric but some samples with more massive textures commonly in the cores of thicker flows still retain relict clinopyroxene and igneous textures and show only minor element redistribution five whole rock samples with relict igneous textures and a clinopyroxene mineral separate yield an isochron with an age of 570 36 ma 2sigma and a strontium initial ratio of 0 7035 1 this age is consistent with recent paleontological evidence for a latest precambrian time for catoctin volcanism and along with isotopic age determinations of 680 710 ma for other rift related magmatism suggests either a two stage or a very long protracted episode of continental rifting paleogeographic reconstruction indicates that the original site of eruption for the lavas must have been at least 56 km to the east in the same geographic location from which the mesozoic appalachian tholeiite terrane evolved variations in sr isotopic signatures and differences in major element abundances between these two sequences suggest mantle heterogeneitiesmore that must have developed beneath the eastern north american craton during the interim 400 m y less

palaeohydrology fires and vegetation succession in the southern baltic during the last 7500 years reconstructed from a raised bog based on multi proxy data we present the first 7500 yr long multi proxy record from a raised bog located at the southern baltic coast poland testate amoebae plant macrofossils pollen and microscopic charcoal were used to reconstruct environmental changes in pomerania northern poland kaszuby lakeland from a 7 m thick peat archive of st zki bog dated 5500 bc ad 1250 we obtained a record of proxies representing different spatial scales regional vegetation changed simultaneously with local vegetation and testate amoebae showed a pattern of change similar to that of pollen and plant macrofossils on the basis of the combined proxies we distinguished three hydroclimatic stages moist conditions 5500 3450 bc drier conditions with regionally increased fires up to 600 bc and again moist conditions from 600 bc onward during the drier interval a first climatic shift to wetter conditions at 1700 bc is indicated by regional pollen as the replacement of corylus by carpinus and locally by e g the increase of hyalosphenia elegans and mire plants such as sphagnum sec cuspidata furthermore we observed a correlation since 600 bc among the re expansion of carpinus after a sudden decline ca 950 bc increased peat accumulation increase of hyalosphenia species and fewer fires suggesting lower evapotranspiration and a stable high water table in the bog fagus started to expand after ad 810 gradually replacing carpinus which was possibly due to a gradually more oceanic climate though we cannot exclude human impact on the forests peat accumulation determined by radiocarbon dating varied with bog surface wetness the hydroclimatic phases found in st zki peatland are similar to moisture changes recorded in other sites from poland and europe this is the first detailed record of hydroclimatic change during the holocene in the southern baltic region so it forms a reference site for further studies on other southern baltic bogs that are in progress

compilation of non annually resolved holocene proxy climate records stacked holocene peatland palaeo water table reconstructions from northern britain abstract the number and range of holocene palaeoclimate reconstructions from various regions of the world have increased dramatically over the last decade the data density for many regions and proxies now offers the potential of robust regional scale reconstructions that avoid the problems of records from individual sites and improve communication between palaeoclimate subdisciplines and climate modellers however there are problems with chronological uncertainties and quantification of proxies which make compilation of multiple records difficult here we explore a stacking and tuning approach to the derivation of regional records from peatland climate proxies to test its applicability to non annually resolved terrestrial records twelve individual records from northern britain based on water table reconstructions from testate amoebae analysis were divided into four regions records were detrended normalised and compared within regions to identify clear correlative events the original chronologies of the records were tuned using both these events and independent age markers the stacked record for northern britain indicates pronounced changes to wet conditions at 3600 2760 and 1600 cal yr bp with more minor changes at 3060 2050 1260 860 550 and 260 cal yr bp the main wet phases are highly correlated with mid european lake highstands wider north atlantic climate change inferred from ocean and ice core records and solar variability tuning and stacking of non annual terrestrial palaeoclimate records is a new approach to the compilation and reconciliation of individual records within coherent climatic regions and provides a tool for upscaling of palaeoclimate records for climate model data comparisons

the holocene palaeoenvironmental changes reflected in the multi proxy studies of lake slone sediments se poland abstract multi proxy data from the lake slone sediments se poland yielded information on the holocene changes of lake slone in a karst region changes of limnological conditions and vegetation reconstructions correspond to high resolution multi proxy records from north central europe ostracods showed several small oscillations most significant changes occurred at 12300 cal yr bp younger dryas preboreal transition and between 11800 and 11100 cal yr bp preboreal oscillation lowering of the water table at around 11100 10800 cal yr bp was probably connected with abrupt warming at ca 11000 cal bp temperature and water depth fell at about 8400 8100 cal yr bp 8200 cal yr bp the atlantic period was generally warm and is divided into two parts an older one with comparatively stable water level and a second one between 7000 and 6300 cal yr bp with two phases of higher water level separated by lowering at 6800 cal yr bp at the transition from the atlantic to the subboreal 6200 5950 cal yr bp the dry period is more pronounced than changes in the second half of the atlantic since the beginning of the subboreal an increase in human activity in central europe was the main factor shaping the landscape and changing the limnic regimes

origin and recharge model of the late cretaceous evaporites in the khorat plateau abstract evaporites commonly occur in the mesozoic cenozoic tethyan domain which characterized by extensive late cretaceous potash deposits in the lanping simao basin lsb in southwestern china and in the khorat plateau kp in thailand and laos the lsb and the kp are located in the eastern tethyan tectonic belt the origin of the late cretaceous evaporites in these basins is controversial possibilities include marine continental or hydrothermal origins in addition the recharge model for the major solutes into these evaporitic basins is inadequate whether it is from the kp to the lsb or from the qiangtang to the lsb to the kp in this study 34 gypsum anhydrite and halite samples from two sediment cores collected from the kp were analyzed to determine their stable b sr s isotopic compositions this is the first time that 11b values have been reported for the anhydrite in the study area the origin and evolutionary relationships of these evaporitic basins were investigated based on the geochemical data sedimentary features mineral sequences and stratigraphic ages of the evaporites in the lsb and kp the tectonic evolution and stratigraphic comparisons during the triassic cretaceous in the eastern tethyan domain were systematically reviewed and summarized in order to determine a preferred recharge model for the evaporites in the kp the following conclusions were reached 1 the reconstructed 11b values 38 20 to 51 23 of the parent solution which were based on those of the anhydrite 8 20 to 21 23 and the isotopic fractionation levels 30 2 to 32 7 87sr 86sr ratios 0 70743 0 70846 and 34s values 14 39 to 15 94 of the anhydrite and halite in the kp overlap with those of late cretaceous seawater suggesting a marine origin 2 the similar mineral sequences and b sr s isotopic signatures and the comparable sedimentary features and inherited ore forming ages indicate that evaporites in the lsb and kp have similar solute sources and evolutionary relationships 3 the tectonic evolution and stratigraphy demonstrate that during the late cretaceous paleoseawater from the shan boundary ocean the eastern segment of the meso tethys ocean most likely passed through the southwestern part tengchong baoshan block of sibumasu and preferably recharged marine solutes into the lsb and kp

paleomagnetic evidence for clockwise rotation of the simao region since the cretaceous a consequence of india asia collision samples were collected for paleomagnetic analysis from 36 sites from six formations west of the red river fault in southwestern yunnan province china on the simao block 23 4 n 100 8 e in an attempt to examine the effects of the india asia collision on the asian continent paleomagnetic results from rocks ranging from cretaceous to miocene in age indicate a large clockwise rotation of these sites with respect to stable eurasia since the late cretaceous the tectonic corrected data from cretaceous samples mean direction of two formations are d 112 6 i 34 7 95 7 5 k 9 1 n 45 for eocene samples the data are d 84 7 i 38 9 95 7 6 k 12 0 n 32 and for miocene samples they are d 21 1 i 35 5 95 7 1 k 15 3 n 29 the samples from the paleocene and pliocene are either remagnetized or too weak to provide stable directions the cretaceous sites were sampled from folded beds and these sites pass the fold test the amount of rotation seen in this study r 86 1 9 9 as a mean value for the cretaceous r 76 8 11 for the eocene and r 14 7 10 0 for the miocene is significantly larger than that documented in previous studies from the lower cretaceous of northwestern and central yunnan province and may indicate that differential rotation has taken place in the region this rotation can be explained by the northward motion and collision of india with asia in the paleocene which caused continuous deformation of southwestern china in the form of strike slip faulting and clockwise rotation it is concluded that the rotation and deformation resulting from this collision probably continued from the paleocene until at least the miocene

structure of the crust and upper mantle beneath the great valley and allegheny plateau of eastern pennsylvania 1 comparison of linear inversion methods for sparse wide angle reflection data we use p data extracted from a small number of wide angle recordings of quarry blasts to construct averaged one dimensional velocity models of the crust beneath portions of the great valley newark basin valley and ridge and allegheny plateau of the central appalachians of pennsylvania using the linear form of the equations for p in terms of slowness depth structure we compare inversion results for the extremal backus gilbert and generalized least squares methods although the uncertainties are large the models do show a well constrained increase in midcrustal velocities and crustal thickness beneath the allegheny plateau inversion of precritical reflections from the moho suggests bounds of 7 1 7 6 km s on p wave velocity and 3 9 4 2 km s on s wave velocity near the base of the crust p wave velocity models for the great valley show a crustal thickness between 40 and 45 km with an average velocity between 6 4 and 6 6 km s models for the allegheny plateau show a larger crustal thickness 47 52 km and a much higher average velocity 6 8 6 9 km s estimates of average shear wave velocities for the great valley range from 3 6 to 3 8 km s with crustal thickness estimates between 37 and 44 km for the relatively small number of singular values retained standard errors in depth for models derived by generalized least squares range from 1 to 2 km for the p wave slowness models and from 2 to 4 km for the s wave models extremal depth bounds in general are 2 to 3 times as wide corresponding uncertainties in interval velocity estimated from resolving kernels in slowness range from 0 15 to 0 45 km s for p wave models and from 0 15 to 0 40 km s for s wave models t2 x2 inversion of pmp data gives similar estimates for total crustal thickness and average velocity after correction for refraction effects t2 x2 inversion of pmp data for a fourth profile suggests the possibility of a slight thickening of the crust 47 48 km directly beneath the axis of the great valley gravity low estimates of average vp vs for the crust based on average velocities for models derived by generalized least squares inversion range from 1 73 to 1 77 estimates based on travel time ratios for events interpreted as p wave and s wave reflections from the moho lie between 1 75 and 1 79 for a crust in which the effects of velocity anisotropy can be neglected these estimates correspond to crustal averages between 0 25 and 0 27 for poisson s ratio the one dimensional velocity models derived here provide estimates of the long wavelength component of velocity structure besides demonstrating the maximum resolving power inherent in a limited p data set these averaged models can be used for migrating reflection data and as starting models for determining two dimensional velocity structure

rich fen development in ce europe resilience to climate change and human impact over the last ca 3500 years here for the first time in se poland we document the long term development of a rich fen and assess its sensitivity to climate change and human impacts over the last ca 3500 years our results are based on a high resolution continuous plant macrofossil remains mollusc and pollen record complemented by geochemical mineral magnetic and physical characterisation and radiocarbon dating from bagno serebryskie rich fen located in se poland based on the palaeoecological data we distinguished five stages of wet habitat conditions 5000 3300 2800 2150 1600 1100 750 230 150 10 cal yr bp and five dry periods at ca 3300 2800 2150 1600 1100 750 230 150 10 to 64 cal yr bp the pollen and geochemistry records particularly pb show that the first human activity in the study area occurred ca 3200 cal yr bp and increased markedly from 500 cal yr bp affecting local plant development including the population size of cladium mariscus our study has shown that despite human impact drainage fire bagno serebryskie peatland has hosted rare presently protected species such as cladium mariscus for hundreds of years we conclude that in common with ombrotrophic bogs rich fen ecosystems can provide a reliable source of palaeoclimatic and palaeohydrological data our study also shows that a large peatland 376 ha can be as sensitive a palaeohydrological archive as smaller mires

700 ma rift event in the blue ridge province of virginia a unique time constraint on pre iapetan rifting of laurentia discovery of compositionally distinctive rhyolites produced from a peralkaline volcanic center within the late neoproterozoic robertson river batholith and which are intercalated with terrestrial deposits of the previously undated mechum river formation indicates that rift related sedimentation and magmatism were ongoing at 702 705 ma about 130 m y before the breakup of laurentia recognition of late neoproterozoic age rhyolites in central virginia indicates that rift related magmatism was more widespread along the incipient eastern present coordinates margin of laurentia than previously thought neoproterozoic rifting in the blue ridge province of virginia appears to have been part of a broad scale process that affected most if not all of the preserved margins of laurentia the association of similar extension related terrestrial deposits and compositionally distinctive felsic rocks elsewhere may provide a unique marker for testing proposed predrift configurations of the late neoproterozoic supercontinent rodinia

holocene climate variability as reflected by mid european lake level fluctuations and its probable impact on prehistoric human settlements abstract a data set of 180 radiocarbon tree ring and archaeological dates obtained from sediment sequences of 26 lakes in the jura mountains the northern french pre alps and the swiss plateau was used to construct a holocene mid european lake level record the dates do not indicate a random distribution over the holocene but form clusters suggesting an alternation of lower and higher climatically driven lake level phases they provide evidence of a rather unstable holocene climate punctuated by 15 phases of higher lake level 11 250 11 050 10 300 10 000 9550 9150 8300 8050 7550 7250 6350 5900 5650 5200 4850 4800 4150 3950 3500 3100 2750 2350 1800 1700 1300 1100 750 650 cal bp and after 1394 ad a comparison of this mid european lake level record with the gisp2 polar circulation index pci record the north atlantic ice rafting debris ird events and the 14 c record suggests teleconnections in a complex cryosphere ocean atmosphere system correlations between the gisp2 pci the mid european lake level the north atlantic ird and the residual 14 c records suggest that changes in the solar activity played a major role in holocene climate oscillations over the north atlantic area

macrofossil evidence of late holocene presence of aldrovanda vesiculosa l in central eastern europe poland and east africa tanzania to date the seeds of waterwheel plant aldrovanda vesiculosa were only found in europe in sediments of the eemian and mazovian interglacials the absence of a vesiculosa seeds in european holocene deposits is probably due to unfavorable climatic conditions i e lower temperature during this period in temperate zones a vesiculosa reproduces mainly in a vegetative way it rarely blooms and only occasionally produces seeds in this paper subfossil seeds of a vesiculosa were identified in two peat bogs one sucha kobyla in se poland and another one kyambangunguru in sw tanzania single seeds of this plant were found in a peat layer from the polish site formed after 1600 ad as well as in sediments accumulated around 440 ad in the tanzanian one to our knowledge this is the first time that seeds of a vesiculosa are found in holocene deposits in the world our findings provide new data on the distribution of a vesiculosa over the late holocene

the remaking of the mengyejing potash deposit in yunnan china evidence from rb sr isotopic systematics abstract the mengyejing potash deposit mpd is the first significant ancient potash deposit ever found in china and it was considered to have formed during the middle to late cretaceous the 87 sr 86 sr ratios of potash bulk samples suggest that both bedded and veined potash orebodies of the mpd have been affected by igneous activity resulting from decompression melting of a metasomatically altered depleted mantle from 16 ma to present the rb sr isotopic systematics of the potash bulk samples define several apparent isochrons ranging from 0 609 0 026 to 14 23 0 63 ma with the maximum age being consistent with previous k ar ages of the k bearing minerals from the mpd such isotopic signatures imply that the mpd may have been affected by multiple stage fluid flow events since the mid miocene consisting of hydrothermal fluids continental fresh water and or hot spring water it is very likely that the mpd is still affected by fluid flow events in modern times the mineral assemblage of halite sylvite with minor amounts of carnallite was formed due to the recrystallization and diagenetic modification by hydrothermal fluids some characteristics of halite photomicrographs and inclusions and the lack of original halite chevron patterns are also supportive of the hypothesis that the deposit has undergone a diagenetic modification and dissolution recrystallization processes

the lackawanna synclinorium pennsylvania a salt collapse structure partially modified by thin skinned folding the lackawanna synclinorium is a 110 km long structural trough in the appalachian foreland of northeastern pennsylvania in map view its hinge displays a concave to the foreland i e concave toward the west curve historically the entire synclinorium was thought to be an alleghanian thin skinned contractional structure that formed similarly to the fold trains of the central appalachian valley and ridge province interpretation of seismic reflection data across the structure however suggests that the synclinorium formed primarily by the removal of salt the trend of the central and northern synclinorium reflects the location of upper silurian salina salt in the southern synclinorium the salt collapse structure translated northwestward over a thrust ramp joining detachments in the cambrian waynesboro formation and the salina group interpretation of seismic reflection data also suggests that the basement cover contact deepens westward and that basement penetrating reverse faults and a neoproterozoic rift basin are present beneath the synclinorium we speculate that 1 partial barriers due to sedimentation and or reef formation and 2 localized subsidence over a neoproterozoic rift zone may have formed a late silurian restricted basin that allowed thick accumulations of salina salt regional scale salt shale flow and or foreland directed i e westward fluid migration during the alleghanian orogeny might have removed as much as 700 m of salt the removal of this salt caused the overlying strata to collapse downward and form the synclinorium only in the southern synclinorium was the collapse structure modified significantly by decollement tectonics thus the map view curvature of the structure reflects greater tectonic shortening and westward translation toward the foreland in the southern synclinorium compared to the northern synclinorium

geothermometry from brine analyses lessons from the gulf coast u s a abstract geothermometers based on mineral water equilibria are of limited use at temperatures characteristic of hydrocarbon production from sedimentary basins metastable detrital phases such as alkali feldspars and plagioclase persist to temperatures characteristic of the deepest wells sasmpled approaching 200 c and equilibria involving stable phases such as albite illite and quartz are not commonly achieved empirical relations such as that between mg and li are more successful in predicting subsurface formation water temperatures than are equilibrium relations involving quartz carbonates or feldspars the concentrations of most components in saline formation waters seem to be governed by kinetic rather than by equilibrium considerations

sedimentology of the cretaceous maha sarakham evaporites in the khorat plateau of northeastern thailand abstract evaporites of the cretaceous to early tertiary maha sarakham formation on the khorat plateau of southeast asia thailand and laos are composed of three depositional members that each include evaporitic successions each overlain by non marine clastic red beds and are present in both the khorat and the sakon nakhon sub basins these two basins are presently separated by the northwest trending phu phan anticline the thickness of the formation averages 250 m but is up to 1 1 km thick in some areas in both basins it thickens towards the basin centre suggesting differential basin subsidence preceding or during sedimentation the stratigraphy lithological character and mineralogy of the evaporites and clastics are identical in both basins suggesting that they were probably connected during deposition evaporites include thick successions of halite anhydrite and a considerable accumulation of potassic minerals sylvite and carnallite but contain some tachyhydrite and minor amounts of borates during the deposition of halite the basin was subjected to repeated inflow of fresher marine water that resulted in the formation of anhydrite marker beds sedimentary facies and textures of both halite and anhydrite suggest deposition in a shallow saline pan environment many halite beds however contain a curious sieve like fabric marked by skeletal anhydrite outlines of gypsum precursor crystals and are the product of early diagenetic replacement by halite of primary shallow water gypsum the 34s isotopic values obtained from different types of anhydrite interbedded with halite range from 14 3 to 17 0 cdt suggesting a marine origin for this sulphate bromine concentration in the halite of the lower member begins around 70 ppm and systematically increases upward to 400 ppm below the potash rich zone also suggesting evaporation of largely marine waters in the middle member the initial concentration of bromine in halite is 200 ppm rising to 450 ppm in the upper part of this member the bromine concentration in the upper member exhibits uniform upward increase and ranges from 200 to 300 ppm the presence of tachyhydrite in association with the potassic salts was probably the result of 1 the large volumes of halite replacement of gypsum on a bed by bed basis releasing calcium back into the restricted waters of the basin and 2 early hydrothermal input of calcium chloride rich waters the borates associated with potash rich beds likely resulted from erosion and influx of water from surrounding granitic terrains however hydrothermal influx is also possible interbedded with the evaporites are non marine red beds that are also evaporative with displacive anhydrite nodules and beds and considerable amounts of displacive halite the 34s isotopic values of this anhydrite have non marine values ranging from 6 4 to 10 9 cdt these data indicate that the khorat and sakhon nakhon basins underwent periods of marine influx due to relative world sea level rise but were sporadically isolated from the world ocean

climate change vegetation development and lake level fluctuations in lake purwin ne poland during the last 8600 cal bp based on a high resolution plant macrofossil record and stable isotope data δ13c and δ18o abstract this paper presents a history of the vegetation in lake purwin ne poland and its catchment along with water level changes for the last 8600 cal bp the reconstructions are based on a high resolution plant macroremains analysis and the stable isotope record in authigenic carbonates a fine fraction that is precipitated within the epilimnion of the lake the stable isotope records suggest that the lake had throughflow during the holocene and that isotope data can therefore be used in palaeoclimatic reconstructions the 18o values record the thermal maximum of the holocene and the subsequent cooling of the upper holocene water level changes and the history of the lake s productivity are both recorded in the 13c values a chronology is established using radiocarbon dating of terrestrial plant macrofossils the vegetation and water levels in lake purwin reflect regional climate changes the combination of the lithology along the sedimentary sequence the results of the plant macroremains analysis and the isotope data allowed several alternating periods of high 8600 7300 6500 5200 4400 3500 and 3000 950 cal bp and low 7300 6500 5200 4400 3500 3000 and 950 to 59 cal bp water stands to be distinguished in lake purwin low water levels are indicated by sediments that are enriched in coarse plant detritus seeds of rubus ideaus fruits of uritca dioica and more macroremains of alnus glutinosa and rushes

a delayed climatic response to solar forcing at 2800 cal bp multiproxy evidence from three irish peatlands multiproxy palaeohydrological records from three raised bogs in northern ireland indicate that a major shift to wetter cooler climatic conditions postdated the rapid decrease in solar activity at 2800 cal bp by 100 years this event is bracketed by two wiggle match radiocarbon dated cryptotephra layers in each profile enabling a high degree of chronological precision these replicated data corroborate previous findings based on irish peat humification profiles and may indicate spatial complexity in the climatic response to solar activity between oceanic and continental areas

reactivity of evaporites during burial an example from the jurassic of alabama the jurassic louann salt was the first significant sedimentary unit to accumulate in the gulf of mexico sedimentary basin br cl and sup 87 sr sup 86 sr ratios of halite from a single core into the top of the formation record the evaporation of normal seawater to bittern stage the bittern zone today consists of intergrown halite and sylvite the br and rb contents of the solid phases along with sup 87 sr sup 86 sr ratios and rb sr systematics are inconsistent with precipitation of the existing phases from seawater evaporated in jurassic time rather petrography and fluid inclusion and solid phase chemistry from the bittern zone is consistent with postdepositional water rock interaction which diagenetically modified a marine bittern assemblage to halite sylvite the chemistry of the br and rb rich saline formation waters characteristic of this area today likewise may reflect water evaporite interaction during burial

response of a spring fed fen ecosystem in central eastern europe nw romania to climate changes during the last 4000 years a high resolution multi proxy reconstruction we document the long term development of a spring fed fen assessing its sensivity to climate changes over the last ca 4000 years our investigation is based on high resolution continuous plant macrofossil remains and mollusc records complemented by pollen geochemical analysis and radiocarbon dating of valea morii located in the feleac hills transylvanian depression in nw romania central eastern europe based on our palaeocological data we have distinguished three stages of wet habitat conditions two stages between 4000 and 2450 cal yr bp and one in the last 800 cal yr bp and one dry stage between ca 2450 and 800 cal yr bp these local habitat conditions appear to reasonably reflect regional climate characteristics high resolution analysis of two replicated cores documented a mostly comparable pattern of local plant and mollusc succession and stable isotope values from ca 500 cal yr bp the appearance of c mariscus during the last two centuries may be related to increased wetness and associated active caco3 precipitation which allowed this plant to colonise the spring fed fen studied however it can be not excluded that the occurrence and spread of a cladium mariscus population at this site during the last two centuries might have been partly favoured by the warming of the climate after the little ice age the potential of carbonate oxygen stable isotope values as an indicator of major trends in climatic change both temperature and humidity in mountain spring fed fen deposits is shown carbon isotopes in the carbonates were found to be useful in reconstruction of changes in vegetation soil development and the dissolution of bedrock carbonates primarily as a reaction to changes in climate humidity

evidence from northwest european bogs shows little ice age climatic changes driven by variations in solar activity fluctuations in holocene atmospheric radiocarbon concentrations have been shown to be due to variations in solar activity analyses of both 10 be and 14 c nuclides cone rm that production ratechanges during

palaeozoic and mesozoic tectonic evolution and palaeogeography of east asian crustal fragments the korean peninsula in context east and southeast asia comprises a complex assembly of allochthonous continental lithospheric crustal fragments terranes together with volcanic arcs and other terranes of oceanic and accretionary complex origins located at the zone of convergence between the eurasian indoaustralian and pacific plates the former wide separation of asian terranes is indicated by contrasting faunas and floras developed on adjacent terranes due to their prior geographic separation different palaeoclimates and biogeographic isolation the boundaries between asian terranes are marked by major geological discontinuities suture zones that represent former ocean basins that once separated them in some cases the ocean basins have been completely destroyed and terrane boundaries are marked by major fault zones in other cases remnants of the ocean basins and of subduction accretion complexes remain and provide valuable information on the tectonic history of the terranes the oceans that once separated them and timings of amalgamation and accretion the various allochthonous crustal fragments of east asia have been brought into close juxtaposition by geological convergent plate tectonic processes the gondwana derived east asia crustal fragments successively rifted and separated from the margin of eastern gondwana as three elongate continental slivers in the devonian early permian and late triassic late jurassic as these three continental slivers separated from gondwana three successive ocean basins the palaeo tethys meso tethys and cenotethys opened between these and gondwana asian terranes progressively sutured to one another during the palaeozoic to cenozoic south china and indochina probably amalgamated in the early carboniferous but alternative scenarios with collision in the permo triassic have been suggested the tarim terrane accreted to eurasia in the early permian the sibumasu and qiangtang terranes collided and sutured with simao indochina east malaya in the early middle triassic and the west sumatra terrane was transported westwards to a position outboard of sibumasu during this collisional process the permo triassic also saw the progressive collision between south and north china with possible extension of this collision being recognised in the korean peninsula culminating in the late triassic north china did not finally weld to asia until the late jurassic the lhasa and west burma terranes accreted to eurasia in the late jurassic early cretaceous and proto east and southeast asia had formed palaeogeographic reconstructions illustrating the evolution and assembly of asian crustal fragments during the phanerozoic are presented d 2005 international association for gondwana research published by elsevier b v all rights reserved

origin of a boreal birch bog woodland and landscape development on a warm low mountain summit at the carpathian pannonian interface we analysed two peat cores of late glacial origin from a bog woodland in the male karpaty mts sw slovakia using plant macrofossil pollen peat chemistry and charcoal analyses to trace local successional patterns regional vegetation development and occurrence of rare species

a paleoweathering profile from griqualand west south africa evidence for a dramatic rise in atmospheric oxygen between 2 2 and 1 9 bybp a core drilled near wolhaarkop in griqualand west south africa intersected highly oxidized kuruman iron formation below red beds of the gamagara formation the lateral equivalents of the kuruman iron formation in this drill hole consist largely of siderite ankerite magnetite greenalite and quartz the oxidation of the kuruman iron formation in wol 2 occurred almost certainly during weathering prior to the deposition of the gamagara formation the date of this weathering episode is bracketed between about 2 2 and 1 9 bybp by the age of the ongeluk lavas in the transvaal sequence below the unconformity and by the age of the hartley lavas in the olifantshoek group above the unconformity the ratio of iron to sio2 in the several facies of the weathered kuruman iron formation in wol 2 is nearly the same as that in their unweathered equivalents since sio2 loss during weathering was almost certainly minor the similarity of the fe sio2 ratio in the weathered and unweathered bif indicates that nearly all the feo in the kuruman iron formation was oxidized and retained as feo3 during weathering such a high degree of iron retention is best explained by an o2 content of the atmosphere or 0 03 atm at the time of weathering such an o2 pressure is very much greater than that suggested by the composition of paleosols developed on basalt or 2 2 bybp but is consistent with the highly oxidized nature of the 1 85 by flin flon paleosol the new data suggest that po2 rose dramatically from about 1 percent pal present atmospheric level to or 15 percent pal between 2 2 and 1 9 bybp

three dimensional seismic imaging of a protoridge axis in the main ethiopian rift models of continental breakup remain uncertain because of a lack of knowledge of strain accommodation immediately before breakup our new three dimensional seismic velocity model from the main ethiopian rift clearly images mid crustal intrusions in this active transitional rift setting supporting breakup models based on dike intrusion and magma supply the most striking features of our velocity model are anomalously fast elongate bodies velocity v p 6 5 6 8 km s extending along the rift axis interpreted as cooled mafic intrusions these 20 km wide and 50 km long bodies are separated and laterally offset from one another in a right stepping en echelon pattern approximately mimicking surface segmentation of quaternary volcanic centers our crustal velocity model combined with results from geologic studies indicates that below a depth of 7 km extension is controlled by magmatic intrusion in a ductile middle to lower crust whereas normal faulting and dike intrusion in a narrow zone in the center of the rift valley control extension in the brittle upper crust this zone is inferred to be the protoridge axis for future seafloor spreading

seismicity seismic reflection gravity and geology of the central virginia seismic zone part 3 gravity bouguer gravity anomalies at 1 870 locations on the central piedmont of virginia from 37 37 n to 37 52 n and 77 44 w to 78 23 w display patterns of variation produced by upper crustal density contrasts and thickening of the crust in a west northwest direction no other deep sources are evident upper crustal density contrasts are associated with rock units known from geologic mapping the subsurface distribution of these rock units interpreted from seismic reflection data was confirmed by measured variations in gravity a two dimensional model analysis indicates the following average in situ density values for the principal formations arvonia formation 2 77 gm cc columbia granite 2 75 gm cc tonalite and 2 73 gm cc pegmatite chopawamsic volcanics 2 77 gm cc felsic units and 2 79 gm cc malic units catoctin lynchburg evington 2 82 gm cc maidens gneiss 2 78 gm cc and grenville basement 2 71 gm cc gravity anomalies are consistent with the existence of a major thrust fault at depths between 9 km and 16 km that probably separates grenville basement rocks from younger catoctin lynchburg rocks these anomalies confirm that the slight eastward dip of this thrust fault beneath the western part of the area increases significantly east of 78 05 w

structure and origin of holocene cold events abstract the present interglacial the holocene spans the period of the last 11 700 years it has sustained the growth and development of modern society the millennial scale decreasing solar insolation in the northern hemisphere summer lead to northern hemisphere cooling a southern shift of the intertropical convergence zone itcz and a weakening of the northern hemisphere summer monsoon systems on the multidecadal to multicentury scale periods of more stable and warmer climate were interrupted by several cold relapses at least in the northern hemisphere extra tropical area based on carefully selected 10 000 year long time series of temperature and humidity precipitation as well as reconstructions of glacier advances the spatiotemporal pattern of six cold relapses during the last 10 000 years was analysed and presented in form of a holocene climate atlas hoclat see http www oeschger unibe ch research projects holocene atlas a clear cyclicity was not found and the spatiotemporal variability of temperature and humidity precipitation during the six specific cold events 8200 6300 4700 2700 1550 and 550 years bp was very high different dynamical processes such as meltwater flux into the north atlantic low solar activity explosive volcanic eruptions and fluctuations of the thermohaline circulation likely played a major role in addition internal dynamics in the north atlantic and pacific area including their complex interaction were likely involved

orogenic bending around a rigid proterozoic magmatic rift beneath the central appalachian mountains abstract the transition zone between the modern northern and southern appalachian mountains is located in pennsylvania where the structural orientation of the fold and thrust belt changes from north south to east west and the orogeny narrows significantly vintage studies of wide angle reflection and temporary broadband seismic data suggest that the crust beneath the 8 km of foreland basin sequences was thickened and heavily intruded around the margins of and beneath a failed neoproterozoic rift we use receiver function analysis of broadband seismic data recorded by additional and permanent stations along with forward and inverse modeling of bouguer gravity data to constrain the geometry and depth extent of mafic intrusion and underplating in the rift as well as the role of this proterozoic heterogeneity on the location and geometry of the curvature of the appalachian orogen the receiver function analyses suggest that the crust is 47 49 km thick beneath the ancient rift about 5 7 km thicker than the surrounding area inverse models of gravity data indicate that the 300 km long zone of thickened high density crust is bounded on both the nw and se sides by steep contacts its shorter ne and sw margins are also steep contacts interpreted as crustal scale faults forward modeling of the gravity data constrained by the receiver function crustal thickness estimates sparse seismic reflection data and euler deconvolution solutions implies that the proterozoic rift has been heavily intruded as well as thickened by a 7 10 km mafic underplate its margins appear to have been sheared along ne striking fault zones that parallel appalachian thrust sheet transport directions these combined results suggest that the mid and lower crust of the proterozoic rift was enriched with pyroxene which strengthened the crust locally and localized compressional strain along its margins during the north american african collision compressional strain in the pre appalachian crystalline crust to the southwest and northeast of the proterozoic rift may have been more distributed leading to the formation of oblique slip faults orthogonal to the axes of folds and leading to the curvature in the pennsylvania salient additionally the thrust sheets are stacked most thickly in front of the rift suggesting that the rift served as a backstop during collision

the role of fire in landscape dynamics an example of two sediment records from the rodna mountains northern romanian carpathians fire is an important disturbance agent worldwide and one of the major causes of geomorphological change dependent on its characteristics size duration temperature fire induces changes in soil stability modifying infiltration and promoting soil erosion here we employ a suite of physical mineral magnetic loss on ignition geochemical xrf derived elemental data biological macro charcoal pollen proxies and dating measurements ams 14c 210pb and 137cs to examine the relationship between fire activity sedimentary characteristics and geomorphological change over the holocene our results highlight that fire events imprint a magnetic signature characterised by secondary ferrimagnetic assemblage particularly very fine superparamagnetic sp magnetite and maghemite in lake buh iescumare the early holocene is characterised bymoderate fire activity and coarser sediment particle size indicating a relatively unstable catchment affected by burning events which activated erosional processes subsequently the late holocene 4 000 0 cal yr bp is marked by intermittently variable fire activity with sporadic increases between 3 400 and 3 200 cal yr bp and around 2 000 cal yr bp when burning was strong enough to lead to the magnetic enrichment of topsoil and detrital inputs to the lake in our high resolution record lake tiol the interval 2 500 700 cal yr bp and also the last 100 years are characterised by intense burning that coincides with sustained surface soil erosion and magnetic enrichment the fire erosion landscape relationship varies over time being highly dependent on fire behaviour fire temporal and spatial distribution and landscape features slope soil type vegetation cover

pennsylvania salient of the appalachians a two azimuth transport model based on new compilations of piedmont data new compilations of geometry and tectonic transport in the pennsylvania salient suggest that these features continue uninterrupted from the piedmont through the valley and ridge provinces these data are the basis for a new two azimuth transport model for origin of the curvature edge geometry of an eocambrian craton and a thickened stratigraphy acted as templates for alleghanian regional decollement first as reading prong n35 w motion followed by n68 w blue ridge motion both displacements involved some drag rotation and overprinting in a central zone this model avoids the problem of minimal tangential stretching explains the anthracite basins as trailing edge graben and basin structures against the autochthonous pocono plateau and produces the nittany juniata culmination as an overprinted pileup of duplexes in the central zone the model of detachment followed by changing azimuth of motion of a megadecollement sheet may apply to other salients throughout the world

drought as a stress driver of ecological changes in peatland a palaeoecological study of peatland development between 3500 bce and 200 bce in central poland abstract we reconstructed 3300 years 3500 bce and 200 bce of the development history of the r bien peatland located in central poland using pollen macrofossil testate amoebae cladocera chironomidae and geochemistry central europe particularly poland is characterised by a transitional climate that is influenced by continental and atlantic air masses which makes this region very sensitive to climate change our results demonstrate the high potential of the r bien peat record to reconstruct palaeohydrological dynamics the studied time interval is characterised by two pronounced dry periods from 2500 to 1700 bce and from 700 to 500 bce and two significant increases in the water table from 1000 to 800 bce and from 500 to 250 bce the timing of the wet shift at 600 bce corresponds to wet periods at different sites in central and eastern europe our investigation reveals a more complicated and complex than previously assumed set of climatic relationships in europe between 3500 bce and 200 bce which might be linked through complex teleconnections of atmospheric circulation patterns only reconstructions that are based on an understanding of current observations from peatlands and lake ecosystems may lead to a better interpretation of past climate changes

the jinshajiang ailaoshan suture zone china tectonostratigraphy age and evolution abstract the jinshajiang suture zone is important for enhancing our understanding of the evolution of the paleo tethys and its age tectonic setting and relationship to the ailaoshan suture zone have long been controversial based on integrated tectonic biostratigraphic chemostratigraphic and isotope geochronological studies four tectono stratigraphic units can be recognized in the jinshajiang suture zone the eaqing complex the jinshajiang ophiolitic melange the gajinxueshan group and the zhongxinrong group isotope geochronology indicates that the redefined eaqing complex composed of high grade metamorphic rocks might represent the metamorphic basement of the jinshajiang area or a remnant micro continental fragment eaqing complex protolith rocks are pre devonian and probably of early middle proterozoic age and are correlated with those of the ailaoshan complex two zircon u pb ages of 340 3 and 294 3 ma separately dated from the shusong and xuitui plagiogranites within the ophiolitic assemblage indicate that the jinshajiang oceanic lithosphere formed in latest devonian to earliest carboniferous times the oceanic lithosphere was formed in association with the opening and spreading of the jinshajiang oceanic basin and was contiguous and equivalent to the ailaoshan oceanic lithosphere preserved in the shuanggou ophiolitic melange in the ailaoshan suture zone the latter yielded a u pb age of 362 41 ma from plagiogranite the re defined gajinxueshan and zhongxinrong groups are dated as carboniferous to permian and latest permian to middle triassic respectively on the basis of fossils and u pb dating of basic volcanic interbeds the gajinxueshan group formed in bathyal slope to neritic shelf environments and the zhongxinrong group as bathyal to abyssal turbidites in the jinshajiang ailaoshan back arc basin latest permian earliest middle triassic synorogenic granitoids with ages of 238 18 and 227 5 255 8 ma respectively and an upper triassic overlap molasse sequence indicate a middle triassic age for the jinshajiang ailaoshan suture formed by collision of the changdu simao block with south china

high resolution reconstruction of wetness dynamics in a southern boreal raised bog finland during the late holocene a quantitative approach a high resolution plant macrofossil analysis was applied to investigate wetness dynamics in a southern finnish boreal bog kontolanrahka during the last 5000 years the chronological control and the age depth model were based on 40 ams radiocarbon dates pollen analysis provided information on regional scale vegetation changes macrofossil analysis revealed prominent changes in vegetation assemblages during the late holocene indicating fluctuations in water table the reconstruction suggests that at the coring point which nowadays is a relatively wet lawn habitat type has repeatedly varied between transient communities similar to those currently represented in dry hummocks very wet lawns and even hollows in order to quantify historical changes in water table generalized additive models gam were used to investigate the current relationships between surface plant species and water table depth modern water table measurements and a survey of associated plant communities along moisture gradients prov

bog burst in the eastern netherlands triggered by the 2 8 kyr bp climate event the nature and cause of the so called 2 8 kyr bp event have been a subject of much debate peat sequences have provided much of the evidence for this event but the process link between climate and peatland response is not well understood multiproxy high resolution analysis of a core from bargerveen in the eastern netherlands based on pollen non pollen palynomorphs testate amoebae and geochemistry identified an abrupt shift from relatively dry to extremely wet conditions radiocarbon based wiggle match dating wmd and biostratigraphy based on the pollen record show that this shift in local hydrology occurred around 2800 cal yr bp we interpret an erosional hiatus lasting up to 950 years immediately prior to this as the effect of a bog burst after excessive rainfall this phenomenon was not limited to our sampling location but occurred over a large part of the former bargerveen peat at the hiatus contains microfossils that reflect temporary eutrophication as a consequence of local fires and secondary decomposition because of increased drainage after the erosion event our data show how detailed multiproxy analyses can elucidate the past response of peatlands to changing climate and suggest that the climatic change in northwest europe at this time caused major non linear disruption to these ecosystems

fluid inclusion evidence for the deposition and diagenesis of the patience lake member of the devonian prairie evaporite formation saskatchewan canada abstract low bromine concentrations radiometric ages textural relations and large scale dissolution and collapse features in devonian potash deposits of the elk point basin in southern saskatchewan indicate that diagenetic processes and late influxes of water have variably recrystallized the salts lack of correlation between homogenization temperature th d or 18o values of fluid inclusions in the salt with stratigraphic position further indicates that the sequence is not primary the stable isotopic compositions of fluid inclusion waters including those in chevron texture halites are not those expected for primary crystallization waters and in conjunction with th indicate recrystallization occurred at temperatures of 35 70 c from water originating in formations above the prairie evaporite formation using th as an estimate of the depth of burial and stable isotopes as indicators of the source of fluids three major recrystallization events related to the evolution of the elk point basin can be recognized

early holocene succession of vegetation and molluscs in lake jaczno east central europe abstract here we present results of high resolution palaeoecological studies of the organic deposits accumulated in lake jaczno located in the north eastern poland plant macrofossils and malacological analyses complimented by radiocarbon dating ams were undertaken to reconstruct early holocene succession of the pioneer wetland plants and molluscs in the lake ecosystem numerous presence of charcoal pieces 1 mm and fungal remains sclerotia in the peat layer accumulated on the mineral ground document dry habitat what coincides with warm and dry climate conditions in the early holocene recorded in this part of europe change to lacustrine environment documented by accumulation of the carbonate gyttja on the highly decomposed peat layer took place ca 10 500 cal yr bp the current morphology of lake jaczno in which several basins can be distinguished suggests that different age of sediments accumulated at the bottom part at our sampling sites might result from different sizes of the buried dead ice blocks and their heterochronous final melting the first aquatic plants that appeared in lake jaczno were chara sp ceratophyllum demersum and nymphaea alba the appearance of cladium mariscus in lake jaczno ca 9400 cal yr bp was synchronous with the substantial spread of this plant in this region which coincided with increased climate humidity the first molluscan species that colonized the lake ecosystem were gyraulus crista and bithynia tentaculata species living on macrophytes and valvata piscinalis typical for habitats characterized by a thick layer of plant detritus

reconstructing climate change and ombrotrophic bog development during the last 4000 years in northern poland using biotic proxies stable isotopes and trait based approach article i nfo in this study we present a record spanning the last 4000 years from a baltic bog kusowskie bagno in northern poland using numerous biotic and abiotic proxies such as testate amoebae depth to water table reconstruc tions stable carbon isotopes 13 c plant macrofossils proxies for local vegetation and mire surface wetness pollen and spores proxies for regional vegetation and human impact we reconstructed and identified the re gional hydro climatic signal of kusowskie bagno bog and compared it to other bog records around the baltic sea our aims were to 1 combine the species traits of bryophytes and testate amoebae and more common proxies isotopes plant micro and macro remains to infer past peatland development 2 compare the hydro climatic signal of kusowskie bagno bog to existing records around the baltic sea we found that kusowskie bagno bog was very wet during the last 4000 years and even drainage and peat exploitation had not disturbed its hydrology in northern part in the last 200 years carbon isotopes and plant macrofossils were significantly re latedtospecifictraitsoftestateamoebae whichinturnreflectedthewatertablechangesoverthelast4000years kusowskie bagno recorded at least the following wet shifts ad 250 550 850 1250 and 1700 while wet condi tions occurred during the migration period at ca ad 550 furthermore the testate amoeba based quantitative wetness reconstruction in kusowskie bagno bog resembles the pattern observed in other sites around the baltic i e estonia finland ireland northernbritainandthe7500 yearrecordfromthe st zkibog northern poland our results provided statistically validated evidence that interactions between plant and microbe need to be more considered further to reconstruct past hydrological this is the first study of past hydro climatic changes in peatlands based upon a trait based approach

the age and timing of folding in the central appalachians from paleomagnetic results comparison of the paleomagnetic pole positions of late paleozoic secondary magnetizations with a time averaged reference apparent polar wander path for north america shows that sedimentary rocks within the central appalachians were remagnetized in the later half of the permian between ca 255 and 275 ma ages of remagnetization do not vary for sites distributed along or across strike of the central appalachian fold and thrust belt or across the appalachian plateau in new york nor do they vary with stratigraphic position of the host rocks however the pattern of folding relative to remagnetization across the valley and ridge and great valley in pennsylvania maryland and west virginia shows a distinct temporal variation individual fold tests yield postfolding magnetizations near the hinterland margin of the fold and thrust belt synfolding magnetizations in the central part of the belt and prefolding magnetizations near the foreland because of the similar age of the late paleozoic magnetization we conclude that rocks across the central appalachians were remagnetized in a relatively short period of time as folding and thrusting propagated more slowly toward the foreland we interpret this pattern to indicate that older folds near the hinterland grew prior to remagnetization folds in the central region grew during remagnetization and folds near the foreland grew after remagnetization rapid remagnetization relative to folding is also evident from the physical characteristics and magnetic properties of secondary hematite in remagnetized synfolding folds in such folds rocks were apparently remagnetized during an increment of fold growth in which there was partial and possibly negligible fold limb rotation collectively these results may constrain the mechanism for basinal fluid mobilization during deformation current models for remagnetization involve the migration of chemically active brines into the foreland during tectonism if realistic our results bear on this model by suggesting that brine migration was not directly related to the successive emplacement of individual thrust sheets as has been suggested for other fold and thrust belts

continental scale temperature variability during the past two millennia past global climate changes had strong regional expression to elucidate their spatio temporal pattern we reconstructed past temperatures for seven continental scale regions during the past one to two millennia the most coherent feature in nearly all of the regional temperature reconstructions is a long term cooling trend which ended late in the nineteenth century at multi decadal to centennial scales temperature variability shows distinctly different regional patterns with more similarity within each hemisphere than between them there were no globally synchronous multi decadal warm or cold intervals that define a worldwide medieval warm period or little ice age but all reconstructions show generally cold conditions between ad 1580 and 1880 punctuated in some regions by warm decades during the eighteenth century the transition to these colder conditions occurred earlier in the arctic europe and asia than in north america or the southern hemisphere regions recent warming reversed the long term cooling during the period ad 1971 2000 the area weighted average reconstructed temperature was higher than any other time in nearly 1 400 years

euler deconvolution using differential similarity transformations of gravity or magnetic anomalies euler deconvolution of gravity and magnetic anomalies can be used to estimate the coordinates of a simple point source and the level of a constant background in the deconvolved field by testing a series of structural indices by using differential similarity transformations dsts joint estimations of the source coordinates the structural index and the coefficients of a linear background trend become possible dsts calculated from the derivatives of the interpreted field depend on the position of a chosen central point of similarity with respect to the source position on this basis techniques for euler deconvolution of anomalous fields are presented the theoretical formulations of dst and the deduced sets of equations for euler deconvolution are tested and verified on model and field examples of magnetic anomalies caused by one point and two point sources such as thin and thick dikes semi infinite and finite sills contacts steps faulted beds etc the possibility of an optimum estimation of the structural index can be used to define a second acceptance criterion along with the criterion of relative standard deviations the joint application of these two criteria ensures the selection of reliable results the suggested dst techniques are suitable for initial rapid estimations of the source type depth and plane location they may be applied to either profile or gridded data acquired from onecomponent measurements as well as from gradient or three component measurements additional data on the density or magnetization of the sources are not necessary

lake sediment records of atmospheric pollution in the romanian carpathians abstract short lake sediment cores from ten lakes in the romanian carpathians have been characterised both mineral magnetically and geochemically providing an assessment of the potential of these mountain lakes sediment records as a retrospective indicator of atmospheric pollution mineral magnetic characteristics suggests that recent sediments have been affected by atmospheric particulate pollution associated with fossil fuel combustion and vehicle emissions although the properties may also reflect within lake processes metal enrichment factors for contemporary sediments reveal that remote mountain lakes in this region appear to have been impacted by the long range atmospheric transport of metallic pollutants the results suggest that sites in the southern mountains are most impacted although trace metal levels are relatively modest initial findings suggest that some sites have the potential to provide lake sediment based pollution histories that will thereby contribute to a fuller europe wide understanding of the impact of atmospheric pollutants in upland regions

late proterozoic rift control on the shape of the appalachians the pennsylvania reentrant the pennsylvania reentrant the most prominent deviation in the trend of the appalachians is the product of late proterozoic rifting the peters creek formation pennsylvania maryland piedmont contains rift gene rated deep water turbidite deposits of late proterozoic cambrian age these rocks are an extension of the westminster terrane and lie well to the northeast of the southern appalachian late proterozoic cambrian rift basin lynchburg chilhowee group basin the basin into which the peters creek formation was deposited may have connected the southern rift basin with one to the north the preservation of the peters creek formation and other age equivalent units within the pennsylvania reentrant indicates that the new york promontory acted as a buttress to paleozoic orogenic activity

multiproxy surface wetness records from replicate cores on an ombrotrophic mire implications for holocene palaeoclimate records ombrotrophic mires can provide records of palaeoclimate over the mid to late holocene in several areas of the world their potential is currently partly limited by difficulties with scaling indices based on plant macrofossils and humification and the need to account for the internal variability of the mire system this paper explores the use of testate amoebae analysis as a third technique and assesses the minimum within site variability by comparing results from two closely spaced cores reconstruction of surface wetness changes was carried out on cores from the centre of an intermediate raised blanket mire coom rigg moss northumberland by analysis of testate amoebae plant macrofossils and humification surface wetness changes were expressed as mean annual water table changes inferred from testate amoebae assemblages two separate indices based on plant macrofossils and percentage transmission of humification extracts comparisons between the proxies suggest good agreement of general trends in sphagnum peats but some differences in monocot and ericaceous peats the magnitude of surface wetness changes also differs within sphagnum peats the records from the separate cores converge over time and replicability between cores is best in the last 1000 yr changes over this period are similar to those shown by estimates based on documentary sources good agreement is obtained between a normalised plant macrofossil index and normalised reconstructed water table values and it is suggested that this approach could form the basis for improved composite multiproxy records from peatlands copyright 1999 john wiley sons ltd

the origins of the mengye potash deposit in the lanping simao basin yunnan province western china abstract the lanping simao basin lsb is a mesozoic cenozoic continental margin rift basin in western china it formed during the opening and closing of the tethys ocean this basin is also known as a metal belt as it hosts several metal deposits besides the mengye potash deposit however the exact dates of the formation either in the paleocene or the cretaceous and thus the origins of the marine continental or mixed origins of the mengye deposits remain disputed based on the basin s evolution materials of marine origin and or remnant seawater should be present but instead the salt layers of the mengye potash deposit present typically continental lithological features this study examines and reviews evaporative minerals br cl and i cl molar ratios and isotopes of s b and sr i and i cl data for this area has not been previously reported the basin s evaporative minerals are dominated by halite and sylvite the amounts of anhydrite chlorocalcite langbeinite glaserite tachyhydrite and glauberite are small all of these form in both marine and continental environments the values of i and the i cl molar ratios of halite and sylvite are from 0 07 to 0 27 ppm and from 0 03 to 0 11 10 6 respectively dependent on organic substances br and molar br cl values are from 89 08 to 555 45 ppm and from 0 06 10 3 to 0 38 10 3 respectively all of the br cl molar ratios are lower than those of seawater and most of them are 34 s 11 b and 87 sr 86 sr values for evaporative minerals indicate a continental origin for the mengye potash deposit however materials of hydrothermal origin are widely distributed in the basin and may have played an active role for the formation of the potash deposit thus the mengye potash deposit could be of continental origin with a remnant seawater trace

use of magnetic and radiometric measurements to investigate erosion and sedimentation in a british upland catchment in response to the potential shortcomings of single technique strategies in the investigation of erosion and sedimentation a combined magnetic and radiometric 13cs and 210pb approach has been undertaken in the upland watershed lake system of howden reservoir derbyshire by combining these techniques some assessment of sediment sources and the erosion status of the catchment has been achieved alone each approach would have been unable to determine unequivocally sediment provenance furthermore the parallel use of these measurements has highlighted limitations and or uncertainties in both the magnetic and 137cs techniques these problems reflect the particular soil characteristics and drainage conditions of this upland catchment despite the documented severity of peat erosion in the region howden reservoir has a mixture of sediment sources and a relatively moderate rate of sedimentation sediment yields total 127 7 t km 2 yr 1 including organic fraction 31 3 t km 2 yr 1 are however higher than in other british upland areas