geomorphic and biological indicators of paleoseismicity and holocene uplift rate at a coastal normal fault footwall western corinth gulf greece abstract the westernmost part of the gulf of corinth greece is an area of very fast extension and active normal faulting accompanied by intense coastal uplift and high seismicity this study presents geomorphic and biological evidence of holocene coastal uplift at the western extremity of the gulf where such evidence was previously unknown narrow shore platforms benches and rare notches occur mainly on holocene littoral conglomerates of uplifting small fan deltas they are perhaps the only primary paleoseismic evidence likely to provide information on earthquake recurrence on coastal faults in the specific part of the rift whereas dated marine fauna can provide constraints on the average holocene coastal uplift rate the types of geomorphic and biological evidence identified are not ideal and there are limitations and pitfalls involved in their evaluation in a first approach 5 uplifted paleoshorelines may be identified at 0 4 0 7 1 0 1 3 1 4 1 7 2 0 2 3 and 2 8 3 4 m a m s l probably forming after 1728 or 2250 cal b p a most conservative estimate for the average coastal uplift rate during the late holocene is 1 6 or 1 9 mm yr minimum with different amounts of reservoir correction some of the obtained radiocarbon ages of lithophaga sp allow for much higher holocene uplift rates of the order of 3 4 mm yr which cannot be discarded but require further research that the identified paleoshoreline record corresponds to episodes of coastal uplift only cannot be demonstrated beyond all doubt yet it appears the most likely interpretation given the geological and active tectonic context and present knowledge on eustatic sea level fluctuations in the mediterranean proving that the documented uplifts were abrupt i e arguably coseismic is equally difficult but rather probable five earthquakes in the last ca 2000 yr on the coastal fault zone that is responsible for the uplift compare well with historical seismicity and the results of recent on fault paleoseismological studies at the nearby eliki fault zone exact amounts of coseismic uplift cannot be determined precisely unless the rate of non seismic uplift of northern peloponnesus at the specific part of the corinth rift is somehow constrained

crustal structure and surface zonation of the canadian appalachians implications of deep seismic reflection data in 1986 1181 km of marine seismic reflection data was collected to 18 20 s of two way traveltime in the gulf of st lawrence area the seismic profiles sample all major surface tectono stratigraphic zones of the canadian appalachians they complement the 1984 deep reflection survey northeast of newfoundland together the seismic profiles reveal the regional three dimensional geometry of the orogen three lower crustal blocks are distinguished on the seismic data they are referred to as the grenville central and avalon blocks from west to east the grenville block is wedge shaped in section and its subsurface edge follows the form of the appalachian structural front the grenville block abuts the central block at mid crustal to mantle depths the avalon block meets the central block at a steep junction that penetrates the entire crust consistent differences in the seismic character of the moho help identify boundaries of the deep crustal blocks the moho signature varies from uniform over extended di

coastal uplift on active normal faults the eliki fault greece the eliki fault forms part of a system of major normal fault segments that borders the southern margin of the gulf of corinth half graben radiocarbon dating of elevated marine fossils reveals broadly uniform holocene coastal uplift at a time averaged rate of 1 5 mm yr both along the eliki fault and in the transfer zone that separates it from the neighbouring fault segment coseismic uplift increments are considered to account for only a minor part of the 6 m of emergence recorded here in the last 3000 years reappraisal of shoreline data from the perachora peninsula at the eastern end of the gulf of corinth indicates a similar though less rapid 0 7 mm yr pattern of uniform holocene emergence as these holocene coastal records embody both coseismic and interseismic deformation they can be used to characterise long term tectonic strain

holocene and quaternary uplift in the central part of the southern coast of the corinth gulf greece abstract the southern coast of the gulf of corinth greece has long been recognized as an area of rapid quaternary uplift in a normal faulting environment but the amplitude dating and significance of this uplift remain a matter of debate mainly due to the scarcity of reliable and detailed estimates of holocene and longer term uplift evidence of holocene emergence is analysed for two sites in the most uplifted area of the southern coast of the gulf of corinth at mavra litharia the uppermost holocene marine limit has been identified at 9 3 m and dated about 7100 14 c years bp near platanos where the holocene marine limit is above 12 5 m in situ infralittoral boring shells at 11 5 m have been dated about 4800 14 c years bp average uplift rates can be estimated between 2 9 and 3 5 mm year at mavra litharia and possibly even greater ca 2 1 2 7 mm year near platanos the pattern of the variation of holocene uplift along the coast seems to mimic the pattern of late quaternary terraces well constrained in the eastern pattern of the gulf corinth xylokastro area

geophysical studies of the structure of the appalachian orogen in the atlantic borderlands of canada results of 6000 km of crustal seismic profiling are presented with gravity and aeromagnetic maps for the appalachian orogen in eastern canada wide angle seismic surveys show that the central mobile belt of the orogen has a thinner crust than its margins high velocity lower crust attributed to underplating is found below the former laurentian continental margin in newfoundland and below the magdalen basin potential field data are used to trace the surface zones of the orogen from the northeast newfoundland shelf to cape breton but extrapolation to new brunswick and quebec is unclear because of late paleozoic basin development the central mobile belt of the orogen is only a few tens of kilometres wide in southwest newfoundland and cape breton but broadens substantially to around 200 km elsewhere reflection images show a strong deep crustal fabric that runs along the orogen with a margin that crosses into the avalon zone in southern newfoundland but coincides with the avalon gander zone boundary el

crustal strain in central greece from repeated gps measurements in the interval 1989 1997 summary a 66 station gps network spanning central greece first observed in 1989 has been occupied fully on three occasions june 1989 october 1991 and may 1993 subsets of this network bounding the gulf of korinthos have also been occupied in june 1995 october 1995 may 1996 and september october 1997 the first three occupations were processed using a fiducial gps methodology whereas later surveys were processed using code precise orbits combination of data from different surveys to yield smooth site velocities requires global network translations at each epoch to compensate for errors in the realization of the reference frame this method provides a posteriori estimates of the relative coordinate errors and reference frame noise only one earthquake the 1995 june 15 egion event has caused significant local coseismic displacement and its effects on the interseismic velocity field are removed using an elastic dislocation model we constrain the orientation of the 100 yr triangulation gps velocity estimates of davies et al 1997 using 14 sites common to the two networks the goodness of fit of this transformation indicates that the short term and 100 yr geodetic estimates of deformation are highly compatible we infer that short term geodetic studies are capable of determining longer term deformation rates provided that transient local effects can be modelled from the combined velocity field we estimate principal strains and rigid body rotation rates at points on a regular grid using data from neighbouring sites strain rates are high within the gulf of korinthos and much lower elsewhere the extension rate across the gulf of korinthos increases from east to west comparison of the extension rate with historical and recent rates of seismic release of strain reveals significant medium term seismic hazard in the western gulf of korinthos and may also indicate long term aseismic strain

seismicity deformation and seismic hazard in the western rift of corinth new insights from the corinth rift laboratory crl this paper presents the main recent results obtained by the seismological and geophysical monitoring arrays in operation in the rift of corinth greece the corinth rift laboratory crl is set up near the western end of the rift where instrumental seismicity and strain rate is highest the seismicity is clustered between 5 and 10 km defining an active layer gently dipping north on which the main normal faults mostly dipping north are rooting it may be interpreted as a detachment zone possibly related to the phyllade thrust nappe young active normal faults connecting the aigion to the psathopyrgos faults seem to control the spatial distribution of the microseismicity this seismic activity is interpreted as a seismic creep from gps measurements which shows evidence for fast continuous slip on the deepest part on the detachment zone offshore either the shallowest part of the faults is creeping or the strain is relaxed in the shallow sediments as inferred from the large ns strain gradient reported by gps the predicted subsidence of the central part of the rift is well fitted by the new continuous gps measurements the location of shallow earthquakes between 5 and 3 5 km in depth recorded on the on shore helike and aigion faults are compatible with 50 and 60 mean dip angles respectively the offshore faults also show indirect evidence for high dip angles this strongly differs from the low dip values reported for active faults more to the east of the rift suggesting a significant structural or rheological change possibly related to the hypothetical presence of the phyllade nappe large seismic swarms lasting weeks to months seem to activate recent synrift as well as pre rift faults most of the faults of the investigated area are in their latest part of cycle so that the probability of at least one moderate to large earthquake m 6 to 6 7 is very high within a few decades furthermore the region west to aigion is likely to be in an accelerated state of extension possibly 2 to 3 times its mean interseismic value high resolution strain measurement with a borehole dilatometer and long base hydrostatic tiltmeters started end of 2002 a transient strain has

the north american late wisconsin ice sheet and mantle viscosity from glacial rebound analyses abstract observations of sea level and crustal response to glacial loading cycles provide constraints on the mantle rheology function e and as well as on the ice load i with the latter being largely free from a priori glaciological or climate assumptions and appropriate therefore for testing any such hypotheses this paper presents new results for both continental mantle e and i for the late wisconsin ice sheet using geological evidence for relative sea level change rsl and tilting of palaeo lake shorelines complemented with loose constraints from observations of present day radial crustal displacement across north america the focus is on evidence from near or within the former maximum ice margins and the resulting earth response is representative of sub continental mantle conditions the inversion of the sea level information has limited resolution for earth rheology and simple three layer models characterized by depth averaged effective lithospheric thickness h and upper and lower mantle viscosities um and um respectively adequately describe the response function yielding parameters earth model e 6 of h 102 85 120 km um 5 1 1020 3 5 7 5 x1020 lm 1 3 1022 0 8 2 8 x1022 where the numbers in parenthesis are 95 confidence limits the details of the ice sheet with one exception are not strongly dependent on the rheological assumptions within this range the exception is the lower mantle viscosity that remains correlated with the magnitude scaling of the ice sheet a link that is largely broken by introducing constraints from glacial loading effects on the earth s rotation and dynamic flattening the difference between the continental um and the comparable estimate of 1 2 5 x1020 for ocean mantle is statistically significant shoreline gradient information from glacial lakes mcconnell agassiz algonquin and ojibway provide strong constraints on the response within the interior of the ice sheet and the resulting ice sheet model lw 6 is characterized by multiple ice domes from at least 17 18 ka onwards the resolution for earlier periods is largely constrained by global ice volume considerations the two principal domes are over southern nunavut the keewatin dome and over quebec labrador both of 3500 m thickness separated by an ice ridge some 1500 m lower than the domes the latter a requirement imposed by the gradient information over western canada ice thickness gradients east of the cordilleras are partly constrained by the shoreline data for former lake mcconnell as is the lateglacial ice thickness of the keewatin dome and indicate that any ice free corridor between the laurentian and cordilleran components is unlikely to have existed before 13ka reconstructions of the glacial lakes are consistent with the locations and timing of the observational evidence for the four major lake systems with the likely drainage routes identified the evolution of the lw 6 ice volume function expressed as equivalent sea level is characterized by a rapid decrease in ice volume from 15 to 14 5 ka corresponding to the bolling allerod period in the main from rapid ice retreat along the southern margin with further contributions from drainage through the st lawrence river valley and from ice retreat from the major northern straits and gulfs but not hudson strait where the rsl data point to late removal of ice after 10 ka the contribution of the drainage of the lakes to global sea level rise is small

recent controversies in predicting post glacial sea level change abstract we compare recent developments in the numerical prediction of post glacial sea level changes and comment on the controversies associated with these developments we conclude that 1 the broad shelf effect discussed by peltier and drummond 2002 in the context of water load modelling at migrating shorelines is incorporated into the sea level algorithms of johnston 1993 and milne et al 1999 and 2 the procedure used by yokoyama et al 2000 to infer an ice equivalent post lgm sea level rise of 130 135 m is technically sound

holocene sea level changes along the mediterranean coast of israel based on archaeological observations and numerical model local sea level curves reflect global eustatic changes regional isostatic adjustments of the crust to changing ice and ocean volumes and tectonically controlled crustal movements in this study we evaluate the relative contribution of each of these factors to the holocene sea level curve of the mediterranean coast of israel we use archaeological data as constraints on palaeo sea levels and we then compare the observational limits with isostatic models for sea level change across the region the isostatic model includes the contribution arising from the relative minor increase in ocean volumes for the past 6000 years due to residual melting of ice sheets the effect of the changing shape of the ocean basin the time dependence of shorelines as sealevel changes and the changing surface area occupied by ice sheets differences if significant between the observed and predicted change are interpreted as being of tectonic origin the archaeological observations and the model sea level curve along the mediterranean coast of israel were found to be generally consistent and any discrepancies lie within the uncertainties of both values our model predicted that 8000 years ago sea level at the israel coast was at about 213 5 2 m whereas the archaeological data place it at 216 5 1 m by 7000 bp the predicted level has risen to about 27 1 m consistent with the archaeological evidences according to both observations and predictions sea level was still lower than 2 3t o24 5 m at 6000 bp and remained below its present level until about 3000 2000 bp the comparison between the model sea level curve and the archaeological observations also enable to conclude that the average rate of vertical tectonic movement for the last 8000 years at the carmel coast israel has been less than 0 2 mm year q 2001 elsevier science b v all rights reserved

eustatic and tectonic controls upon quaternary coastal sedimentation in the corinth basin greece the late quaternary sedimentology and palaeogeography of the corinth isthmus in central greece is re interpreted a series of beach to shoreface sub sequences are seen each characteristically having an overall fining up character these occur within a coastal facies belt which has prograded to the west computer modelling illustrates the interaction of tectonic displacements and eustatic sea level variation as controls of facies patterns late pleistocene holocene facies geometries are predicted on the basis of published sea level data over that time interval on coastlines undergoing tectonic uplift such as the isthmus of corinth depositional patterns may be characterized by transgressive wedges these sub sequences merge basinwards below sea level minima each transgression relates to a major eustatic sea level peak such first order models are modified by variations in the rate of tectonic deformation the second control on relative sea level position modelled facies patterns are tested on the basis of new 230 th 234 u dates obtained from sclerac tinian corals of the corinth canal area dated sub sequence sediments correspond in age to late pleistocene eustatic highs and observed facies patterns correlate with the major late pleistocene holocene eustatic transgressions of c 100 ka periodicity episodes of intrabasinal normal faulting are isolated from a structural history otherwise dominated by uplift across the isthmus quantification of post depositional vertical tectonic displacements is achieved constraining the eustatic base level at the time of deposition of a dated horizon by reference to the global late quaternary sea level curve the original depositional level is then subtracted from the present outcrop level using available 230 th 234 u dates to establish syn depositional base levels minimum uplift rates of the order of 0 3 m ka 1 are calculated across the area averaged through the late pleistocene and holocene

the seismic velocity structure of northern appalachian crust around western newfoundland the crustal velocity structure beneath western newfoundland is constrained by a reanalysis of older regional refraction profiles together with an analysis of one new profile initial interpretation of the older data gave inconsistent and discontinuous structures that are difficult to reconcile with more recent deep reflection profiles we also show that traveltimes predicted by the earlier models often do not yield acceptable fits to the original observations our reinterpretation reveals a simpler pattern in which the crust is characterized by a persistent high velocity lower crustal hvlc layer this layer has velocities of 7 0 7 9 kmls and thicknesses of 5 23 km it is thickest beneath the grenville crustal block east of the appalachian structural front and thins or is possibly absent within the central block analysis of the new much higher resolution profile off western newfoundland confirms the existence of the hvlc layer with a velocity of 7 2 kmls and thicknesses of 11 19 km increasing to

the helice fault the site of the ancient greek city of helice which was destroyed by an earthquake in 373 bc has never been found we propose that it was submerged as the result of seismic slip on a normal fault traceable se of egion and that the fault was reactivated in 1881 when schmidt reported a fresh scarp 2 m high and 13 km in length at the same locality earlier movements on the fault are inferred from lithophaga borings on coastal sectors of the footwall which yield 14c ages representing over 6 5 m of uplift in the last 4880 years

a charcoal rich horizon at o69 greenland evidence for vegetation burning during the norse landnam it is often assumed that the colonisation of greenland by norse settlers in c a d 985 had a sudden and dramatic effect on the environment involving substantial vegetation clearance and environmental degradation consequently it has been argued that charcoal rich horizons visible in many sections in greenland represent the initial burning of the vegetation by norse farmers to create land suitable for agriculture in this study a charcoal rich layer visible in a modern drainage ditch beside the norse farm of o69 was analysed using archaeobotany sedimentary analysis and radiocarbon dating to test the date and formation processes of the horizon it is demonstrated that the charcoal rich layer at o69 was not derived from in situ vegetation burning in the 10th century and concluded that the layer was probably formed by the addition of midden material to the infields around o69 in the 13th and 14th centuries cal ad perhaps as part of a soil amendment strategy it is argued that caution must be exercised when interpreting charcoal rich horizons as time specific chronological markers in palaeoenvironmental sequences in greenland

holocene sea ice variations in greenland onshore evidence the oldest dated driftwood log from northern greenland is c 9300 cal years old which is about 2000 years younger than the beginning of the last deglaciation and 2000 years younger than the oldes

volcanic forcing of climate over the past 1500 years an improved ice core based index for climate models 1 understanding natural causes of climate change is vital to evaluate the relative impacts of human pollution and land surface modification on climate we have investigated one of the most important natural causes of climate change volcanic eruptions by using 54 ice core records from both the arctic and antarctica our recently collected suite of ice core data more than double the number of cores ever used before reduces errors inherent in reconstructions based on a single or small number of cores which enables us to obtain much higher accuracy in both detection of events and quantification of the radiative effects we extracted volcanic deposition signals from each ice core record by applying a high pass loess filter to the time series and examining peaks that exceed twice the 31 year running median absolute deviation we then studied the spatial pattern of volcanic sulfate deposition on greenland and antarctica and combined this knowledge with a new understanding of stratospheric transport of volcanic aerosols to produce a forcing data set as a function of month latitude and altitude for the past 1500 years we estimated the uncertainties associated with the choice of volcanic signal extraction criteria ice core sulfate deposition to stratospheric loading calibration factor and the season for the eruptions without a recorded month we forced an energy balance climate model with this new volcanic forcing data set together with solar and anthropogenic forcing to simulate the large scale temperature response the results agree well with instrumental observations for the past 150 years and with proxy records for the entire period through better characterization of the natural causes of climate change this new data set will lead to improved prediction of anthropogenic impacts on climate the new data set of stratospheric sulfate injections from volcanic eruptions for the past 1500 years as a function of latitude altitude and month is available for download in a format suitable for forcing general circulation models of the climate system

active faulting within the offshore western gulf of corinth greece implications for models of continental rift deformation discrimination between different lithospheric extension models focusing on the roles of low angle vs high angle faulting and how strain is distributed requires high fidelity imaging of brittle deformation high resolution seismic reflection and multibeam bathymetric data in the western gulf of corinth continental rift were collected to establish the contribution of offshore faults to extension onshore fault slip here is significantly less than expected from geodetic strain rates the rift at this location is a half graben tilted to the north by s dipping faults within the uppermost crust a basement horst on the northern margin is uplifted by the north and south eratini faults and the axial channel is fault controlled subsided lowstand shorelines in the hanging wall of the north eratini and the well studied aigion fault suggest that the faults have similar displacements summed extension from the four major faults across this part of the rift eliki subchannel south eratini north eratini is 8 16 mm yr thereby reconciling geologic and geodetic data sets distributed deformation across isolated multiple faults can model this part of the rift without recourse to and potentially incompatible with an underlying low angle detachment

coincident seismic wave velocity and reflectivity properties of the lower crust beneath the appalachian front west of newfoundland we have determined the seismic velocity structure of the crust in the vicinity of the appalachian deformation front off western newfoundland and the adjacent gulf of st lawrence these measurements

on post glacial sea level i general theory summary modern analyses of sea level changes due to glacial isostatic adjustment gia are based on the classic sea level equation derived by farrell clark 1976 geophys j r astr soc 46 647 667 the connection between global sea level variations and changes to ocean height that is assumed within this equation breaks down in the presence of a time varying shoreline geometry we present a generalized sea level equation that overcomes this difficulty we also derive analytic expressions for and present schematic illustrations of the error in the ocean height change over finite time intervals introduced in published efforts to incorporate shoreline evolution into the theory of gia induced sea level change this comparison includes studies of shoreline migration due to either local sea level changes or the growth and ablation of marine based ice we conclude that the theories applied by johnston 1993 geophys j int 114 615 634 milne 1998 phd thesis university of toronto toronto and co workers are more accurate than the procedure advocated by peltier 1994 science 265 195 201 1998a geophys res lett 25 3955 3958 1998b rev geophys 114 615 634 although an improvement in the latter has recently been reported peltier drummond 2002 geophys res lett 29 10 1029 2001gl014273 our generalized theory is valid for any earth model in a companion paper we derive the equations necessary to treat the special case of a spherically symmetric linear viscoelastic and rotating earth and we quantify errors associated with previous work

a multiple profile approach to the palynological reconstruction of norse landscapes in greenland s eastern settlement acknowledgments the leverhulme trust is thanked for financial support gordon cook provided radiocarbon dates thanks are also due to andy mcmullen for botanical identifications and assistance in the field and to sikuu motzfeld for hospitality during fieldwork we are also grateful to emilie gauthier mike kaplan pete langdon and alan gillespie for their comments

water load definition in the glacio hydro isostatic sea level equation abstract models of glacio hydro isostatic rebound and the concomitant sea level change have been progressively improved over the past three decades recently the procedures used by the group at the australian national university anu for the hydro isostatic component of the theory have been questioned quat sci rev 21 2002 409 although the details of the anu group s procedures have not been published because they are mainly computational in nature rather than representing significant conceptual advances because of this criticism we set out here in detail the procedures that have been used for the treatment of the migration of shorelines as sea levels rise and fall the effect of retreat and advancing grounded ice on shelves and shallow seas and the transitions from grounded to floating ice and vice versa we conclude that there is no basis for the criticism that these formulations and their implementation provide a high resolution and complete description of both sea level change and of the estimates of volumes of ice exchanged with the oceans the results from this formulation are confirmed by the entirely independent analyses of milne et al quat sci rev 21 2002 361 and mitrovica and milne geophys j int 2002 submitted for publication who conclude that our formulation is significantly more accurate than the procedure advocated by peltier science 265 1994 195 rev geophys 36 1998a 603 geophys res lett 25 1998b 3955

crustal thickness under the gulf of st lawrence northern appalachians from gravity and deep seismic data we have determined crustal thickness in the gulf of st lawrence an area that corresponds to an offset of the main northern appalachians units a complete bouguer anomaly was calculated from recent depth to basement compilations and sediment densities from well data the moho surface was obtained by inverting the bouguer anomaly assuming a single density contrast at depth and using an average depth provided by deep reflection seismic data the resulting crustal model shows a moho depth of 42 44 km beneath the grenville craton north of the appalachian deformation front south of this front the depth to moho displays a pronounced thinning of the crust beneath the carboniferous magdalen basin this is in striking contrast to the deep seismic data which give a moho depth of about 43 km the modelling of the bouguer anomaly in the magdalen basin taking into account the seismic reflection and refraction data reconciles these different results and suggests that a 43 km deep moho beneath the basin is as

rates of uplift investigated through 230th dating in the gulf of corinth greece abstract the sr u and th isotope compositions of fourteen coral samples from raised terraces on the south side of the gulf of corinth greece have been analysed by high precision mass spectrometry 234u 230th ages of pure coral aragonite together with 87sr 86sr determinations provide the basis for an investigation of tectonic uplift rates in the w aegean over the last 350 ka the corinth basin is a continental fault bounded depression formed by crustal extension northeast of subduction along the hellenic trench and in the vicinity of the aegean volcanic arc the sr isotope composition of present day seawater in the gulf of corinth is indistinguishable from that in the north atlantic but this was not the case during earlier high stands 120 190 and 240 ka ago when 87sr 86sr ratios as estimated from the corals were apparently significantly lower than the ratios of their open ocean counterparts although the cause of the earlier discrepancy between the two reservoirs is unknown it is likely to result from one of two processes either circulation between the gulf of corinth and the open ocean may have been restricted at certain earlier highstands or the lower sr isotope compositions could be the result of diagenetic effects the latter hypothesis is favoured by large variations in the initial 234u 238u ratio of the corals by their unusually high th contents and by the observation that the underlying massive miocene carbonate is severely altered the ages of the corals as determined by mass spectrometry ranges between 70 2 and 385 5 ka for samples from terraces at elevations of 7 to 65 m above present sea level a mean uplift rate for this area of 0 3 mm yr over the last 350 ka has been estimated by combining the coral ages with terrace heights allowing for changes in sea level during this period the uplift here is probably caused by footwall uplift adjacent to large normal faults and put constraints on likely fault slip rates extension rates and the timescales of earthquake recurrence

tectono stratigraphic terranes in cape breton island nova scotia implications for the configuration of the northern appalachian orogen cape breton island is divided into four terranes on the basis of contrasts in pre carboniferous geology the blair river complex in the north is an exposure of north american grenvillian basement analogous to the humber zone basement in newfoundland ordovician to devonian metavolcanic metasedimentary gneissic and granitic rocks of the aspy terrane are correlative with parts of the gander terrane of newfoundland and new brunswick the bras d9or terrane characterized by low pressure gneisses a carbonate clastic platform sequence and late precambrian early cambrian plutons may be correlative with units previously included in the gander terrane in southern newfoundland and the avalon terrane in southern new brunswick the mira terrane in southeastern cape breton island including late precambrian to early cambrian volcanic and sedimentary sequences and fossiliferous cambrian ordovician units is clearly part of the avalon terrane therefore with the exception of the dunnage terrane which is not represented in cape breton island the terranes of newfoundland continue through cape breton island they are offset to the northwest to the mainland part of the appalachian orogen in new brunswick

rates of tectonic uplift in the corinth and megara basins central greece we present evidence of the rates of late quaternary tectonic uplift that have affected parts of central greece during this period of active extension and basin formation dual lines of evidence indicate upper pleistocene to holocene uplift rates of the order of 0 3 mm yr 1 for the corinth and megara basins first u series disequilibrium ages of acropora sp corals from uplifted marine sediments are used to derive minimum average rates of vertical displacement since deposition second the geometries of cyclical transgressive sequences and of erosional terraces are consistent with the radiometric evidence and the known history of late quaternary sea level fluctuations two types of uplift are distinguished on the basis of structural relationships 1 fault block rotation about a horizontal axis tilting in response to footwall uplift on the active normal fault bounding the alkyonides gulf and 2 a more regional uplift which affects the corinth basin and peloponnesos to the south the results of u series dating are discussed in the light of initial 234u 238u activity ratios derived from the coral samples which are higher than for average marine waters 1 17 1 31 compared to 1 14 these values may be related to a variable freshwater input to the structurally confined gulf of corinth or alternatively they may reflect a previously higher global 234u 238u activity ratio in marine waters or post mortem enrichment in 234u although the mechanism of the latter is not yet understood

glacial rebound and relative sea level variations a new appraisal summary late pleistocene and holocene changes in sea level at technically stable shorelines contain information on the melting history of the ice sheets and on the response of the earth to changes in surface loads on time scales of 104yr some separation of parameters defining the ice loads and the earth s response can be achieved by examining sea level change at different sites around the world and at different epochs this paper examines the mathematical requirements for obtaining satisfactory solutions for the sea level equation rather than emphasizing results for the earth s response to the surface loads an examination of the equation expressing the sea level variation on a viscoelastic earth indicates that careful consideration needs to be given to both the definition of the ice load and the geometry of the redistributed water load if geophysically significant earth response parameters are to be deduced from observations of relative sea level the spectrum of the 5 x 5 area mean description of the ice load widely used in glacial rebound studies contains significant power at high degrees n 30 and can result in substantial spatial variations in sea level unless a thick lithosphere is introduced in the earth s response function a smoothed 1 1 description of the ice model avoids these high degree oscillations in relative sea level and produces satisfactory sea level results without requiring a thick lithosphere at far field sites the holocene sea levels are sensitive to the earth s response to the meltwater loading in the vicinity of the site and a high degree spatial resolution of coastline geometry is required to model the mantle flow driven by the differential loading about the site at some sites convergence of the solution to the sea level equation is not obtained even when the solution is expanded to degree 180 convergent solutions at lower degrees can be achieved by introducing earth models with a moderately thick lithosphere if high resolution ice and meltwater load models are not used then the tendency will be to overestimate the effective elastic thickness of the lithosphere estimates of mantle viscosity are also of questionable value if these high resolution models are not used a preliminary examination of sea levels at sites in both the near and far field places an upper limit of about 50 80 km on the effective lithospheric thickness these sea level observations are also consistent with an upper mantle viscosity of about 1021 pas with a lower mantle viscosity in the range of 1021 1023pa s

lithoprobe onshore seismic reflection transects across the newfoundland appalachians vibroseis seismic reflection data have been recorded to 18 s two way traveltime along three transects across the island of newfoundland the upper crust has both steep and subhorizontal reflectors consistent with a ramp flat style of deformation whereas the middle and lower crust are largely free of regional flats reflectors descend through ca 20 km of vertical section in the middle and lower crust to flatten into the moho or perhaps cut through it in places the moho is interpreted to be no younger than the dipping reflectors reflection fabrics interpreted to be indicators of dominantly mid ordovician to mid silurian strain show consistent orientations among the transects and divide the crust into two blocks a northwestern block is characterized by upper and middle crustal reflectors dipping mostly southeast at variable angles this block is underlain to the southeast by supposedly younger and dominantly northwesterly dipping reflectors that define a northwest tapering wedge shaped block floored

quaternary evolution of the corinth rift and its implications for the late cenozoic evolution of the aegean summary we present geological and morphological observations at different scales to constrain rates of faulting and the distribution of deformation in the seismically active aegean region we focus first on the 130 km long corinth rift an asymmetric graben where a flight of terraces of marine origin are uplifted we show that the edges of the terraces lie in the footwall of the normal fault bounding the corinth rift and correspond to sea level highstands of laic pleistocene age using a detailed analysis of aerial and spot imagery supported by field observations we have mapped 10 terrace platforms and strandlines ranging in elevation from 10 to 400 m over distances of 2 to 20 km from the fault the elevation of the terraces inner edges was estimated at 172 sites with an error of 5m this data set contains a precise description of the uplift and flexure of 10 different palaeohorizontal lines with respect to the present sea level to date the deformation we correlate the corinth terraces with late pleistocene oxygen isotope stages of high sea level stands and with global sea level fluctuations using a thick elastic plate model consistent with our current understanding of the earthquake cycle and a boundary element technique we reproduce the geometry of the shorelines to constrain both mechanical parameters and the slip on the fault we show that the seismogenic layer behaves over the long term as if its elastic modulus were reduced by a factor of about 1000 all the terraces are fitted for fault slip increasing in proportion to terrace age and the component of regional uplift is found to be less than 0 3 mm yr 1 the best fits give a slip rate of 11 3 mm yr 1 on the main rift bounding fault over the last 350 kyr other geological and morphologic information allows us to estimate the total age of the main fault 1 ma and to examine the mechanical evolution of the corinth rift the minimum observed sediment thickness in the gulf places an extreme check on the results of the modelling and a lower bound on slip rate of 6 7 mm yr 1 40 per cent less than estimated with modelling even this slip rate is nearly 10 times higher than for comparable features in most of the aegean and elsewhere in the world at a larger scale the spacing and asymmetry of the rift systems in the aegean suggest strain localization in the upper mantle with slow extension starting 15 myr ago or earlier the more recent 1 myr rapid phase of rifting in corinth partly reactivated this earlier phase of extension the younger faulting in corinth appears to result from its present location in the inhomogeneous stress field process zone of the south westward propagating tip of the southern branch of the north anatolian fault we extend these relations to propose a mechanical model for the late cenozoic evolution of the aegean as the arabia europe collision progressed in eastern turkey it caused anatolia to move to the west and the north anatolian fault to propagate into the aegean where the early slow extension started to be modified about 5 ma ago the process of propagation dramatically increased the activity of some but not all of the earlier rifts the model we present is compatible with tectonic observations as well as with the seismicity the palaeomagnetic rotations and the displacement field now observed with gps and slr

corinth rift margin uplift new evidence from late quaternary marine shorelines 1 new evidence for uplift of the southern margin to the corinth rift one of the world s most rapidly extending continental regions defines an area of uniform uplift separating a more rapidly uplifting western rift flank from a slowly backtilting eastern flank this major tectonic boundary coincides with geophysical evidence for a junction between flat underlying subducted oceanic plate and steep subduction we propose that trench rollback by the anatolian plate over the subducting african plate has led to differential uplift and possible migration of active faulting at the southern rift margin in the last few million years

a reevaluation of the position of the baie verte brompton line in the quebec appalachians the influence of middle devonian strike slip faulting in gaspe peninsula the baie verte brompton line bbl the surface expression of the taconian suture in the canadian appalachian orogen extends from southern quebec to the northeast end of newfoundland in the que

underestimation of volcanic cooling in tree ring based reconstructions of hemispheric temperatures a large volcanic eruption in ad 1258 1259 is expected to have caused substantial climate cooling but evidence for this effect is absent from tree ring based temperature reconstructions numerical modelling of tree growth shows that the lack of cooling is probably an artefact caused by low sensitivity to cooling in trees growing near the treeline

palaeoecological and historical evidence for manuring and irrigation at garðar igaliku norse eastern settlement greenland palaeoenvironmental data are presented from the site of gar ar modern igaliku the location of the cathedral and the bishop s farm in the norse eastern settlement of greenland the latter was founded from c ad 985 and abandoned some time during the fifteenth century inspection of drainage ditches located in close proximity to the settlement ruins revealed inter alia an organic rich unit containing cultural debris worked wood animal bone stone and charcoal dated by ams radiocarbon dates on seeds to the period c ad 1110 1370 fossil insect and pollen assemblages contained within the deposit appear representative of natural environments primarily wet eutrophic meadows but are mixed with high frequencies of a range of synanthropic insects including human and animal ectoparasites that could only derive from indoor habitats this is strongly indicative of the manuring of fields with waste from houses and byres in order to increase yields of hay large amounts of hay would have been necessary to prov

environmental change in eastern greenland during the last 1300 years evidence from foraminifera and lithofacies in nansen fjord 68 n lithofacies and benthic foraminiferal analyses of two sediment cores bs1191 k13b and k14 from nansen fjord eastern greenland show evidence of changing oceanographic and sea ice conditions from

the effect of spatially non uniform water loads on prediction of sea level change summary numerical modelling of postglacial rebound predics a spatially variable pattern of sea level change yet many previous models predicting late pleistocene sea level change either neglect the load of water added to the oceans or assume a spatially uniform time dependent load over the whole ocean this is a poor approximation of the load near the former ice sheet since sea level change varies geographically in addition the coastline goemetry changes through time a spectral technique has been used to solve the sea level equation on an earth model with axisymmetric distribution of ice and oceans and also for a realistic ice ocean configuration the axisymmetric model is useful for demonstrating the fundamental physics involved in sea level changes caused by changes in surface loads in particular it can be seen that the elastic and gravitational response to the load is spread over a great distance whereas the viscous response is more localized a realistic ice ocean configuration has been used to demonstrate that neglect of the melt water load underestimates the amount of uplift in fennoscandia and other regions where rebound occurs in the ocean as previously noted by wu peltier 1983 in hudson bay and that movement of the coastlines and spatially varying water loads must both be included in calculations for the north sea and other near field regions with shallow seas sea level calculations including these effects and careful analysis of the sea level and ice melting record are required to determine modifications to the viscosity profile and ice model inferred by previous inaccurate models of the ocean load in the near field

the seismic velocity structure of the newfoundland appalachian orogen the deep structure of the newfoundland appalachian orogen is investigated by analyses of three intersecting seismic refraction wide angle reflection profiles which traverse the gander and dunnage zones or central mobile belt of newfoundland a simultaneous travel time inversion for velocity and interface was applied to the in line seismic refraction wide angle reflection data and constrained by synthetic amplitude models the results of the modeling procedure show a subhorizontally layered crust with upper crustal velocities ranging from 5 4 to 6 2 km s a midcrustal velocity of 6 25 6 35 km s and a lower crustal velocity of 6 7 0 2 km s the top of the lower crust is marked by a series of prominent reflections between 18 and 23 km depth which suggest a complex layered velocity interface strong laterally coherent moho reflections indicate a sharp crust mantle transition at 35 3 km the uppermost mantle has a velocity of 8 0 0 2 km s and a reflecting horizon at 55 km depth suggests an increase to velocities approaching 8 5 km s normal moveout corrections applied to fan profiles provide constraining evidence for the reflecting horizon at the top of the lower crust and laterally continuous moho reflections at 11 12 s two way travel time comparisons with a coincident deep seismic reflection profile show that the refraction and reflection mohos match to better than 2 3 km bulk poisson s ratios of 0 23 0 24 for the whole crust calculated from pmp sms travel times suggest a crust dominated by quartzofeldspathic lithologies and a notable absence of voluminous mafic additions to the lower crust the absence of a deep crustal root coupled with the bulk intermediate composition inferred for the lower crust from the seismic refraction wide angle data implies that the crust beneath central newfoundland has undergone multiple periods of reactivation and equilibration following successive orogenic episodes

new insights into the uplifted roman harbour at mavra litharia n peloponnese greece in the geodynamic context of the southern margin of the corinth gulf abstract recent archaeological excavations at mavra litharia in the area of aigeira n peloponnese have brought to light the eastern landward extension of a jetty the erosion of the cliff along the modern coast and the excavations at the inner side of the northern coastal section of the jetty provided a clearer picture of its structure significantly different than this presented in previous studies the harbour installations are assigned to between the 2nd century and the first half of the 3rd century ad according to the study of the structure the mobile findings and the epigraphic data biomarkers attached to the structure define the sea level during its operation and demonstrate the current uplift position the observed damage that has sustained the structure of the ancient jetty suggests that its destruction was co seismic and reveals the direction of seismic waves from the west reconstruction of the displaced blocks of the jetty in their original position archaeological interpretation and dating of the structure biomarker information and glacio isostatic modelling determine the sea level since the function of the harbour and the uplift of the ancient jetty as 5 35 0 37 m the age of the biological indicators 1686 cal p 264 ad is consistent with archaeological dating and the period of the sudden abandonment of the under reconstruction nearby theatre of ancient aigeira mid 3rd century ad the uplift of the roman harbour occurred at least in two phases initially by 4 35 m around 1686 bp and subsequently by 1 0 m around 657 bp the mean tectonic uplift rate of 2 81 0 20 mm yr for the coast in mavra litharia similar to these for the entire western part of the south shore of the corinth gulf is higher than the mean uplift rate of 1 21 0 28 mm yr in the easternmost edge the westernmost edge at the rio antirio strait presents very high subsidence rate of 5 17 0 47 mm yr

environmental impacts around the time of norse landnam in the qorlortoq valley eastern settlement greenland abstract palynology radiocarbon dating and open section stratigraphies from archaeological trenches are used to examine the impact of human activity around the time of norse landnam on vegetation and landscape associated with a small farm o34 in the qorlortoq valley eastern settlement greenland 61 n 45 w peat deposits from a mire abutting the norse ruins revealed a discontinuous palaeoenvironmental record containing a possible hiatus from ca ad 410 1020 palaeovegetational data were recovered either side of this period pollen assemblages suggest that open salix scrub dominated the landscape during the pre settlement phase the later phases of landnam resulted in the creation of hay fields and heavily grazed grassy heath site abandonment is reflected by a re expansion of salix this occurs shortly before the onset of deposition of a sphagnum peat dated to cal ad 1420 1630 2 and reflecting an increase in mire surface wetness probably in response to a deteriorating climate radiocarbon dates were obtained on peat and plant macrofossils sampled from either side of the proposed hiatus at two different but closely spaced landnam period cal bc 2130 1770 and cal ad 240 410 respectively but near synchronous dates for the recommencement of peat growth cal ad 890 1150 for peat and a probably more reliable interval of cal ad 1020 1190 based on plant macrofossils it is suggested that this hiatus may represent the first direct evidence for peat cutting in norse greenland

seismic refraction data in the gulf of saint lawrence implications for the lower crustal blocks a refined model for the wide angle reflection refraction profile 88 3 that crosses the foreland basin of the appalachian orogen is presented the two major layers of the cratonic crust have velocities of 6 2 and 6 7 km s 1 with low gradients near the exposed north american craton the 6 7 km s 1 velocity appears at the shallow depth of 13 km and the m discontinuity at greater than 40 km depth towards the orogen a southeastward dipping ramp is developed at mid crustal levels at the top of the 6 7 km s 1 layer near the appalachian front lower crustal velocities typical of the grenville are replaced with a velocity of 7 2 km s 1 the collinear reflection profile confirms the southward dipping ramp the shallowing m discontinuity and the lateral changes in the lower crust refraction profiles combined with reflection and gravity data are used to distinguish the grenville lower crustal block the grenville lower crustal block is defined as a pattern of lower crustal and upper mantle reflectivity with associated velocities and a more negative gravity anomaly than lower crustal blocks of the appalachian terranes the grenville block terminates northwest of the coast of newfoundland near the appalachian front thus this lower crustal province does not underlie the humber tectono stratigraphic zone this is different than the relationship of the edge of the grenville lower crustal block to surface zones in new england a thick skinned tectonic style with basement involved deformation appears to be typical of the newfoundland appalachians in contrast a thin skinned structural style is observed in new england the change in structural styles occurs in the bend of the appalachian orogen across the gulf of st lawrence

fuel resource utilisation in landscapes of settlement one little understood aspect of the settlement and colonisation of iceland is fuel resource use in this paper we identify fuel ash residues from temporally constrained middens at two contrasting settlement age sites in m vatnssveit northern iceland one high status the other low status and ultimately abandoned fuel residues derived from experimental combustion of historically defined fuel resources are used to provide control for thin section micromorphology and complementary image analyses of fuel residue materials found in the midden deposits the results suggest that fuel resources utilised at the time of settlement were for both low temperature and high temperature use and included a mix of birch and willow wood peat mineral based turf and cow dung there are however marked variations in the mix of fuel resources utilised at the two sites this is considered to reflect social regulation of fuel resources and socially driven changes to local and regional environments that may have contributed to the success or failure of early settlement sites in iceland

late pleistocene and holocene sea level change in greece and south western turkey a separation of eustatic isostatic and tectonic contributions summary sea level change during late pleistocene and holocene times is a combination of eustatic isostatic and tectonic contributions in the central mediterranean sea region of greece and western turkey the isostatic components are important due to the changing gravitational potential of the earth the readjustment of the crust upon the removal of the large ice sheets and the addition of the meltwater into the oceans including the mediterranean changes in relative sea level due to these glacio hydro isostatic adjustments have reached amplitudes of 1 mm yr 1 during the last few thousand years a model for the isostatic contribution to sea level change including the movement of shorelines due to the combined eustatic isostatic changes is developed based on earth model and ice sheet parameters estimated from sea level observations from other areas comparisons of this model with observations of sea level change permit rates of vertical movement to be estimated for late holocene time allowance for the isostatic factors makes a significant difference to these rates the plains of argolis lakonia messinia and navarine in the southern peloponnese for example appear to be tectonically stable on time scales of a few thousand years and longer consistent with the position of the last interglacial shoreline close to the present day sea level the observations here of a rising sea level are largely the consequence of the glacio hydro isostasy and not of a long term tectonic process crete as a whole is subject to tectonic uplift but at variable rates and forms part of an arcuate zone of uplift extending from rhodes and karpathos in the east to kithera in the west at rates that locally exceed 4 mm yr 1 the southern shore of the gulf of corinthos is also subject to uplift at rates approaching 1 5 mm yr 1 these isostatically corrected estimates for the past few thousand years are in agreement with longer term estimates based on the position of the last interglacial shoreline only on the perachora peninsula do the tectonic rates over these two time intervals appear to be in disagreement with the late holocene rates being much higher than the long term rates

rupture creep lamellae and crocodiles happenings in the continental crust from the observation of certain seismic reflectivity patterns in phanerozoic continental crusts a relationship is suggested between 1 rupture and seismicity generally restricted to the upper crust 2 crocodile tectonics a kind of vertical indentation observed by diverging plane reflectors preferably in the middle crust 3 creep and the formation of reflecting lamellae in the lower crust based on these observations and on viscosity depth estimates a conceptual model for the above mentioned structures is presented which is also compatible with observations in older crusts boundary conditions are given for rupture as well as for lamellae forming creep

archaeological and geomorphological indicators of the historical sea level changes and the related palaeogeographical reconstruction of the ancient foreharbour of lechaion east corinth gulf greece abstract study of the architectural morphological and constructional features of the coastal harbour installations of the ancient foreharbour of lechaion indicates that they were built or rebuilt during the period of the roman domination of corinth and has facilitated the reconstruction of the vertical movements and the palaeogeography of the coast on the basis of the current position of the sea level indicators including beachrocks fossilized uplifted and submerged marine notches and ancient coastal harbour installations and the relationship between them the sea level during the roman operation of the harbour was determined to be 0 90 m lower than at present furthermore the subsequent abandonment of the harbour and the siltation of its constructions were determined during two successive tectonic subsidence co seismic events the sea level rose by 2 0 m in total 1 60 m during the first event and 0 40 m during the second one a strong uplift tectonic event followed and the sea level dropped by 1 10 m this regression of the sea was responsible for the present shoreline morphology determination of the sea level fluctuation at the shore of the ancient harbour of lechaion allowed the palaeogeographical reconstruction of the coast in different stages related to these changes

on postglacial sea level summary an exact method is presented for calculating the changes in sea level that occur when ice and water masses are rearranged on the surface of elastic and viscoelastic non rotating earth models the method is used to calculate the instantaneous elastic and delayed vi scoelastic sea level changes following the partial melting of late quaternary ice sheets we find that there can be large errors in the usual assumption that changes in sea level are uniform over the ocean basins if a quantity of ice equivalent to a uniform 100 m rise in sea level melts from the laurentide and fennoscandian ice sheets then in the south pacific the instantaneous rise in sea level can be as large as 120m in the north atlantic the instantaneous rise is always less than 100 m there is a zone in the north atlantic with almost no sea level change and near greenland and norway the sea level falls rather than rises by over 100 m one thousand years after the melting a forebulge migrating towards the ice loads causes water to flow from the south pacific into the north pacific suggesting that raised beaches should occur in the south pacific the gravitational attraction of an ice mass upon a nearby ocean tends to hold sea level high in the vicinity of the ice this extra load near the ice may have a significant influence on postglacial isostatic adjustment

the egion june 15 1995 6 2m l earthquake western greece on june 15 1995 at 00 15 gmt a devastating earthquake 6 2m l occurred in the western end of the gulf of corinth this was followed 15 min later by the largest aftershock 5 4m l the main event was located by the university of patras seismological network patnet at the northern side of the gulf of corinth graben the second event 5 4m l was located also by patnet near the city of egion on a fault parallel to the eliki major fault that defines the south bound of the gulf of corinth graben a seismogenic volume that spans the villages of akrata se and rodini nw and extends to eratini ne was defined by the aftershock sequence which includes 858 aftershocks of magnitude greater than 2m l that occurred the first seventeen days the distribution of hypocentres in cross section does not immediately suggest a planar distribution but rather defines a volume about 15 km depth by 35 km nw se and by 20 km ne sw

a collisional crustal fabric pattern recognised from seismic reflection profiles of the appalachian caledonide orogen abstract deep seismic reflection profiles across the appalachians and across the once contiguous caledonides around britain and ireland show a broadly similar pattern of crustal reflection fabrics the pattern is of two adjacent fabric domains each characterized by dips towards the other bounded by an interface which dips in conformity with one of the fabrics the domain interface strikes parallel to the orogen suggesting a genetic relationship between the fabrics and the orogen from the north sea to the long island platform the domain boundary dips to the northwest in the southern appalachians the pattern appears with less consistency between the charlotte and carolina slate belts the pattern appears with the same polarity as further north but below the coastal plain it occurs with opposite polarity the interface dips to the southeast an attractive but not exclusive hypothesis for explaining the fabric domain contrast is that it results from detachment of all or most of the crust from underlying mantle lithosphere during collisional orogenesis

episodic uplift deduced from holocene shorelines in the perachora peninsula corinth area greece four raised shorelines between 1 1 m and 3 5 m have been identified at two localities on the perachora peninsula and were dated by ams 14c to between 6400 and 1500 calibrated years ago uplift movements seem to have occurred in increments of 0 8 0 3 m with a return period of about 1600 years the last uplift coincided with a regional tectonic paroxysm which has already been documented in several areas of the eastern mediterranean the average uplift rate was probably faster during the holocene than the average since the last interglacial period no important vertical displacement occurred in this area at the time of or after the 1981 earthquake but a new episode of coseismic uplift may be in preparation

relationship between the aspy and bras d or terranes in the northeastern cape breton highlands nova scotia according to previous interpretations the eastern highlands shear zone separates ordovician silurian volcano sedimentary rocks to the west cheticamp lake gneiss of the aspy terrane from late precambrian sedimentary rocks and dioritic tonalitic plutons and early ordovician granite to the east bras d or terrane new mapping discovered a basal conglomerate of the cheticamp lake gneiss that rests on deformed diorite of the bras d or terrane and contains clasts similar or identical to rocks of the bras d or terrane the late precambrian rocks of the bras d or terrane are also overlain by a volcano sedimentary sequence of silurian age clyburn brook formation these observations suggest that rocks of the aspy terrane lie unconformably on those of the bras d or terrane the eastern highlands shear zone is therefore not a terrane boundary the ordovician silurian rocks of the aspy terrane are interpreted to have formed in an arc back arc basin system the back arc basin is interpreted to h

grenvillian basement in the northern cape breton highlands nova scotia the northernmost cape breton highlands are underlain by the blair river complex a distinctive assemblage of basement rocks including felsic and mafic gneisses foliated gabbroic to granitic rocks

geometry and kinematics of active faults and their seismotectonic significance in the western corinth patras rift greece abstract the western part of the corinth patras rift is formed in an area which is being uplifted rifted domains have subsided relative to the adjacent areas in nw peloponnesus and sterea hellas but subsidence rates rarely exceed uplift rates extension is mainly accomplished by wnw trending active faults with lengths up to 25 km most of these faults show an along strike segmentation and often terminate against transfer faults displacement analysis along 170 mesoscopic faults and 36 mappable faults has been carried out to assess slip rates and to estimate the magnitudes and recurrence time intervals of earthquakes occurring along them earthquake magnitude ranges between 5 and 6 7 only eight faults appear to be capable of producing earthquake magnitudes larger than 6 recurrence times of these large earthquakes vary between 80 and 1690 years upper crustal deformation in the western corinth graben can be described by six large asymmetric grabens which are inferred to bottom out to a n dipping curved ramp the asymmetric shape of most wnw trending rifts in the hellenic peninsula including the corinth patras rift promotes the simple shear model of extension against the pure shear model in the upper crustal layer

the aegean sea we summarize briefly the main features of a kinematic model of evolution of the aegean area since 13 ma the formation of the aegean sea by extensional tectonics is related to the subduction of the mediterranean floor below the hellenic arc we then make a quantitative estimate of vertical movements in the aegean area on the basis of geological data and demonstrate that the outer arc was built since the beginning of this episode of subduction by vertical uplift the easiest way to explain the uplift is by underplating finally we discuss briefly the dynamics of the subduction marginal sea formation processes in this continental collision framework

vertical land movements and sea level changes along the coast of crete greece since late holocene abstract geomorphological survey along the coasts of crete revealed widespread evidence of uplifted and submerged tidal notches different phases of beachrock formation and many relics of ancient coastal constructions about 1 6 ka bp when the sea level was at 1 25 0 05 m the western tectonic block of the island uplifted by 9 15 0 20 m in its westernmost extremity and by 2 00 m approximately in its eastern boundary and tilted southeastward repeated preceding episodes of subsidence submerged the western part of the island by 1 60 m in a period of 2300 years along the western coast the younger phase of the submerged beachrocks was identified and measured at nineteen locations together with the submerged tidal notches and archaeological remains land subsidence by 1 25 0 05 m subsequent to the uplift of the western part occurred after the late venetian occupation period ad 1600 coincident with the submersion of the eastern part of the island in central and eastern crete the relative sea level change evidence from tidal notches and beachrocks revealed five distinct sea level stands at 6 55 0 55 m 3 95 0 35 m 2 70 0 15 m 1 25 0 05 m and 0 55 0 05 m the lowest sea level stand can be identified with the oldest dated tidal notch of western crete between 4200 90 b p and 3930 90 b p two subsequent sea levels can be linked with the protopalatial 1900 1700 b c or 1600 b c and neopalatial period 1600 1450 b c of the minoan civilization according to submerged prehistoric morphologies and inundated minoan constructions the change of sea level from 2 70 0 15 m to 1 25 0 05 m is placed between 1450 b c and the fourth century bc the dating of 1 25 0 05 m sea level stand was based on the measurement and interpretation of ancient coastal installations built along the coast of central and eastern crete during classical hellenistic roman byzantine and venetian periods historical sources report a relative sea level rise by 0 70 m during the ad 1604 paroxysmal event over the last 400 years the relative sea level rose by 0 55 m the uplift of the coast of western crete and the submersion in its central and eastern coast indicate that during the ad 365 paroxysmal event the island was split along a tectonic boundary identified with the neotectonic graben of spili and its northern and southern prolongation

a 2500 year record of natural and anthropogenic soil erosion in south greenland the environmental impact of the norse landnam in greenland has been studied extensively but to date no study has quantified the soil erosion that norse agricultural practices are believed to have caused to resolve this problem a high resolution sedimentary record from lake igaliku in south greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use an accurate chronology allows for the estimation of detritic fluxes and their uncertainties land clearance and the introduction of grazing livestock by the norse around 1010 ad caused an acceleration of soil erosion up to 8 mm century in 1180 ad which is two fold higher than the natural pre landnam background from 1335 ad to the end of the norse eastern settlement in the mid fifteenth century the vegetation began to recover from initial disturbance and soil erosion decreased after an initial phase of modern sheep breeding similar to the medieval one the mechanization of agriculture in the 1980s caused an unprecedented soil erosion rate of up to 21 mm century five times the pre anthropogenic levels independently a suite of biological and geochemical proxies including ti and diatom concentrations c n ratio 13c and 15n of organic matter confirm that the medieval and modern anthropogenic erosion far exceeds any natural erosion over the last 2500 years our findings question the veracity of the catastrophic scenario of overgrazing and land degradation considered to have been the major factor responsible for norse settlement demise they also shed light on the sustainability of modern practices and their consequences for the future of agriculture in greenland

northeastern extension and crustal expression of terranes from cape breton island nova scotia based on geophysical data the narrowest section of the appalachian orogen in atlantic canada from grenville age basement in the west to the avalon terrane in the east is preserved in cape breton island where components of four terranes display distinctive stratigraphic igneous metamorphic aeromagnetic and gravity characteristics the blair river complex of northwestern cape breton island is a fragment of grenvillian rocks that is similar to units in western newfoundland the aspy terrane is characterized by mid paleozoic granitic rocks and high pressure paragneisses and appears to continue across the cabot strait as the gander terrane of the hermitage flexure in newfoundland the bras d or terrane is composed of hadrynian to early cambrian low pressure metasedimentary units and dioritic to granitic plutonic rocks as indicated by aeromagnetic anomalies this terrane continues across the laurentian channel to the south coast of newfoundland where it may be terminated by the hermitage fault the avalon terrane of southeaster

an integrated geochemical and palynological study of human impacts soil erosion and storminess from southern greenland since c ad 1000 abstract an integrated pollen analytical and geochemical study is presented from qinngua kangilleq southwest greenland this site was formerly one of the largest farms in the eastern settlement of norse greenland the study is the first to determine what link if any exists between norse landnam early settlement vegetation change soil erosion climate change and peat geochemistry the data suggest that fluxes in lithogenic elements supplied to a peat column by terrestrial sources and atmospheric deposition were coupled to the pattern of local norse settlement beginning cal ad 1020 a severe phase of soil erosion is indicated which is coincident with the landnam horizon this may represent proxy evidence for the stripping of turf for the construction of turf and stone buildings at the farm radiocarbon dates suggest the presence of a hiatus in the sediment column spanning cal ad 1380 1950 following the recommencement of sediment accumulation the geochemical data indicate a critical change in site conditions which may be consistent with the well known change in northern hemisphere atmospheric circulation that started between c ad 1400 and 1420 bromine br and chlorine cl concentrations are demonstrably higher in the sediments dating to the 20th century relative to the pre 15th century deposits rising halogen concentrations at qinngua appear to be correlated with increased levels of na sea salt sodium precipitation in the gisp2 ice core which earlier studies have interpreted as indicative of increased north atlantic storminess

high resolution paleoenvironmental and chronological investigations of norse landnam at tasiusaq eastern settlement greenland abstract high resolution paleoenvironmental data from a peat profile with a small pollen source area are used to reconstruct the impacts of landnam on vegetation and soils at a norse farm complex 2 at tasiusaq comprising two farms in the eastern settlement of greenland analyses include the ams 14c dating of plant macrofossil samples and the use of bayesian radiocarbon calibration to construct improved age depth models for norse cultural horizons the onset of a regional landnam may be indicated by the clearance of betula pubescens woodland immediately prior to local settlement the latter is dated to ad 950 1020 2 and is characterised by possible burning of betula glandulosa scrub to provide grassland pasture for domestic stock clearance and grazing resulted in accelerated levels of soil erosion at a westerly farm this was followed by an easterly migration of settlement and agriculture site constraints prevent an assessment of the demise of the easterly farm but pressures of overgrazing and land degradation may have been the major factors responsible for the abandonment of the earlier farm