the interrelation of glaciotectonic and glaciodepositional processes within the glacial environment abstract in recent years it has been recognised that ice sediment coupling occurred beneath the quaternary ice sheets that advanced over the soft sediments of lowland areas this paper looks in detail at the effects of this coupling on the sediments which results in glaciotectonic deformation and also discusses the interaction of deformation and deposition within the subglacial environment two types of glaciotectonic deformation are discussed that are produced by the active movement of ice 1 proglacial tectonics at the margin which include compressive fold styles such as listric thrusts and faults and open folding 2 subglacial tectonics formed beneath the glacier which include fold styles resulting from simple shear and represent a soft rock purely dynamic shear zone styles of deformation associated with stagnant ice are also investigated we argue that glaciotectonic deformation is a common phenomenon and an integral part of geological record from continental ice sheets it is suggested that zones of deformation within the sediment are related to similar zones of strain in the ice sheet and complex deformation sequences are produced by the superimposition of these differing styles upon one another as the ice sheet advances and retreats it is also argued that subglacial deposition and deformation are related and that on soft beds underformed till is rare whilst deformed till is very common

striated clast pavements products of deforming subglacial sediment studies of modern glaciers have recently drawn attention to the importance of subglacial sediment deformation to glacier dynamics and processes inferences regarding the probable shear strength of this sediment imply that large clasts may in some cases sink to underlying rigid sediment where abrasion by overlying deforming sediment could occur this scenario provides a formative mechanism for striated clast pavements commonly described from the base of fine grained massive diamictons associated with the late pleistocene laurentide ice sheet such a mechanism indicates that at the time of formation of clast pavements overlying diamictons associated with pavements had a low yield strength 0 5 kpa and were deforming mechanically like a debris flow clast pavements may therefore be an important criterion for recognition of sediments deposited by subglacial deformation transport

styles of subglacial glaciotectonic deformation within the context of the anglian ice sheet a substantial proportion of the glacial sediments of east anglia england are chaotic and highly deformed this has been attributed to a direct glaciotectonic deformation or b slumping of glaciomarine sediments we show that interpretation a leads to a classification of subglacial glaciotectonic deposits into sites of constructional deformation where little or no erosion of the preglacial deposits has occurred and styles of deformation are preserved moving up in the sequence and excavational deformation where substantial erosion of preglacial sediments has occurred and deformational styles are superimposed on each other by using glaciological and geotechnical theory we show that the expression of these deformational styles in east anglia is a natural response to the stress fields imposed by the ice sheet and that in consequence their spatial relationships are explicable the depth of deformation is related to the geotechnical properties of till and substrate the stress and effective stress fields and found to be consistent with observations

neogene quaternary slow coastal uplift of western europe through the perspective of sequences of strandlines from the cotentin peninsula normandy france abstract the cotentin peninsula normandy france displays sequences of marine terraces and rasas the latter being wide late cenozoic coastal erosion surfaces that are typical of western european coasts in portugal spain france and southern england remote sensing imagery and field mapping enabled reappraisal of the cotentin coastal sequences from bottom to top the n cotentin sequence includes four previously recognized pleistocene marine terraces t1 to t4 at elevations

climate and vegetation variations since the lgm recorded by biomarkers from a sediment core in the northern south china sea variations in stable carbon isotopic compositions of n alkanes 13calk and n alkane proxies cpi c31 c27 and acl from core md05 2905 20 08 17 n 117 21 6 e in the northern south china sea scs provided evidence of biological responses on adjacent land areas in the form of changes in terrestrial vegetation and provenance of the remains of land plants during and since the last glacial maximum lgm decreased values of n alkane proxies and 13calk over the last 28 ka marked the transition from glacial to interglacial conditions and indicated a greater extent of herbaceous vegetation at the lgm than present and an increased abundance in woody vegetation during the holocene relatively larger 13calk values at the lgm indicated that n alkanes of terrestrial herbs in the sediment core were not only from the leaf waxes of c3 plants such as herbs of artemisia growing on proximate parts of the exposed continental shelf but also from c4 grasses likely from subtropical parts of southeastern china and taiwan island reconstructed sea surface temperatures ssts based on data from the same core revealed that temperatures were 3 c lower than present during the lgm with abrupt variations during both glacial and interglacial periods during the lgm lower temperature and sea level and greater aridity relative to present resulted in an expansion of herbaceous vegetation over an enlarged extent of exposed continental shelf following deglaciation warming and enhanced summer monsoonal activity led to increased humidity and to an expansion of woody vegetation mostly c3 plants during the holocene results also revealed rapid oscillations in c31 c27 ratios over millennial scales with lower values associated with cold stages these low c31 c27 ratios indicated increased input of woody plant material possibly from more extensive gallery forest and greater transport of their plant debris to the coring site perhaps facilitated by enhanced runoff under a strengthened northern hemisphere winter monsoon during short duration cold events copyright 2012 john wiley sons ltd

the chronology palaeogeography and archaeological significance of the marine quaternary record of the west sussex coastal plain southern england u k abstract the quaternary sediments of the west sussex coastal plain have produced a wide range of floral faunal and archaeological remains these sediments consist of marine sands and gravels exhibiting transgressive and regressive trends which occur from present day sea level to c 43 0 m o d and are overlain by terrestrial silts and cold climate periglacial sediments at the present day coastline channel fill deposits occur below modern beach levels new field observations coupled with a re investigation of old sites and literature suggest that five discrete high stands of sea level may be preserved in the area of the west sussex coastal plain age estimates for these deposits suggest that they span large parts of the middle and upper pleistocene oxygen isotope stages 13 to 5 conformable relationships between many of the marine and terrestrial sediments suggest that the potential exists within the area to correlate the marine and terrestrial quaternary stratigraphic records in addition sediments associated with two of these high sea level stands are associated with extensive buried landsurfaces covering large areas of the coastal plain at some locations these intact landsurfaces are associated with evidence for human activity and represent stratigraphic and cultural resources of international importance

acoustic emission uncovers thermal damage evolution of rock abstract the thermal damage evolution of rock closely relates to many important scientific and engineering problems such as the mechanisms of earthquake and the effective extraction of deep geothermal energy however there is lack of rational thermal damage evolution model and the mechanisms of thermal damage are still unclear especially during cooling by use of a specially designed acoustic emission ae test system we explored the thermal damage evaluation in a rock and established a thermal damage evolution model which takes into account both heating and cooling processes the mechanisms of rock damage caused by heating and cooling were analyzed by using a lattice spring model and two different microstructural explanations were found i e heterogeneous microstructure and microdefect structure the damage evolution model can be used for more accurate modeling of these problems which involve rock thermal damage such as induced seismic activity during deep geothermal exploration

u series and amino acid dates from jersey understanding of the raised beach and other interglacial sequences in the southern part of the british isles has been improved through use of the amino acid racemization technique this method has permitted correlation of these isolated and fragmentary marine deposits1 2 which except for the portland site are located around the shores of the bristol channel1 by applying this technique with the u series method we have obtained a geochronometric date from the 8 m raised beach of the belle hougue cave jersey channel islands our results suggest that the 8 m raised beach of the channel should be correlated with isotope stage 5 and that raised beaches above this altitude in the area may pre date this stage and thus also the ipswichian interglacial which forms part of it

modeling the development of marine terraces on tectonically mobile rock coasts abstract a mathematical model was used to study the effect of glacially induced fluctuations in sea level on the formation of wave cut terraces on tectonically mobile rock coasts two deep water wave sets were used to calculate breaker height and depth which along with surf zone width bottom roughness and the gradient of the submarine slope dictated the force exerted at the shoreline an erosional force threshold was employed to represent the variable strength of the rocks the model also considered tidal range the time that the water level spent at each intertidal elevation and the protective effect of debris accumulation at the cliff foot three hundred runs were made with constant sea level and with different rates of rising and falling relative sea level rates of erosion increased with the rate of rising and falling sea level but eventually decreased in some runs with very rapid changes in relative sea level fifty five longer runs were also made with a quaternary sea level model that consisted of 26 glacial cycles representing the period from 2 million to 0 9 million years ago and nine cycles of approximately twice the amplitude and wavelength in the last 0 9 million years these runs were made on a landmass experiencing slow 0 11 mm yr 1 or fast 0 74 mm yr 1 positive or negative changes in the elevation of the land it was found that on rising landmasses erosional coastal terraces are formed during interglacial stages and on subsiding landmasses during glacial stages the number of terraces increased with the rate of uplift and subsidence and with the slope of the hinterland terrace gradient increased with tidal range and decreased with rock resistance the was an inverse relationship between terrace width and the strength of the rock

sediment deformation beneath glaciers rheology and geological consequences experiments beneath breidamerkurjokull in iceland have led to development of flow laws for the subglacial till relating strain rate to shear stress and effective pressure and assuming either bingham fluid or nonlinearly viscous fluid behavior water pressures in the till are less than ice pressures and it is suggested that this may lead to infiltration of ice into the sediment which inhibits sliding at the ice sediment interface where water pressures are equal or near to ice pressures infiltration does not occur and sliding may result a one dimensional theory of subglacial deformation is developed in which the empirical flow law is coupled with a model of subglacial hydrology and consolidation this predicts stable states in which subglacial sediment either does not deform or a dilatant deforming horizon forms with positive effective pressures at the ice bed interface or unstable states where zero or negative effective pressures are predicted time dependent analyses show that response times following perturbations of the system may be of the order of 103 years and thus that unsteady behavior may be normal on glaciers flowing over unlithified sediment beds it is suggested that the natural variability of material properties in subglacial sediment beds leads to the development of drumlins on the glacier bed it is suggested that unstable deformation at zero or negative effective stress leads to piping in subglacial sediments at the glacier terminus and the growth of sediment floored subglacial tunnels their frequency is that which is sufficient to draw down subglacial water pressures so as to prevent unstable deformation where they discharge large water volumes subglacial sediments flow laterally toward them producing tunnel valleys this sediment is then removed by water flowing along the axial tunnel tunnel valleys can be regarded as the equivalent in soft sediment areas of eskers in bedrock areas

subglacial drainage eskers and deforming beds beneath the laurentide and eurasian ice sheets glaciological theory predicts that the subglacial drainage network at the base of gently sloping ice sheets resting on deforming sediment should consist of many wide shallow probably braided canals distributed along the ice sediment interface rather than an arborescent network of relatively few large tunnels as would develop over a rigid substrate a corollary prediction examined here is that eskers which form in large subglacial tunnels should be rare where subglacial bed deformation occurred but they may be relatively common where the bed was rigid bed deformation would be most likely where subglacial till was relatively continuous fine grained and of low permeability that is in regions where till is derived primarily from underlying sedimentary bedrock but unlikely where discontinuous coarse grained high permeability till was derived from underlying crystalline bedrock the observed distribution of eskers in areas covered by the laurentide and eurasian british scandinavian and barents sea ice sheets during the last glaciation shows that most eskers occur over crystalline bedrock overlain by discontinuous high permeability till but are rare or absent over sedimentary bedrock overlain by fine grained low permeability till thus matching reasonably well our prediction glaciological theory and geologic evidence indicate that esker systems on a subcontinental scale are time transgressive sedimentological evidence for a canal drainage system appears to be present in fine grained tills where eskers are largely absent

a 20 m middle pleistocene sea level highstand bermuda and the bahamas due to partial collapse of antarctic ice marine deposits at 20 3 m on the tectonically stable coastlines of bermuda and the bahamas support the hypothesis of a partial collapse of the antarctic ice sheet during the middle pleistocene beach sediments fill a sea cave at 22 m in bermuda and horizontal fenestrae filled beds crop out on platforms at two sites as high as 21 m in eleuthera bahamas carbonate beach sands are bound by an early generation of isopachous fibrous cement that is characteristic of a phreatic marine environment amino acid racemization and tims thermal ionization mass spectrometry dates constrain the age of the deposits to between 390 and 550 ka while proxy evidence supports a correlation with oxygen isotope stage 11 this direct geologic evidence of a 20 decrease in polar ice during the middle pleistocene has important implications for the stability of ice sheets during warm interglaciations

zoophycos cyclicity during the last 425 ka in the northeastern south china sea evidence for monsoon fluctuation at the milankovitch scale in a deep sea piston core covering the last 425 ka from the northeastern south china sea power spectrum analysis of several core data from sediment parameters has been conducted and compared with

small to medium sized glacitectonic structures in till and in its substratum and their comparison with mass movement structures abstract ductile and brittle deformation structures have been observed in till of various origins particularly in subglacial till and flowtill and in the substratum beneath subglacial till although some of the glacitectonic structures have been claimed to be palimpsest structures from debris rich glacier ice such a preservation is not proven to be very common however deformation structures are found in megablocks and other clasts that occur in melt out till and in deformation till most glacitectonic deformation structures are formed in the substratum or in the already deposited subglacial till by an actively moving glacier for instance recumbent folds shears boudins thrusts hook folds diapirs tension fractures till wedges fissility glacitectonic breccia conjugate sets of fractures structures similar to those reported from subglacial primary till and its substratum occur also in flowtill and other mass movement deposits but deformations are less common in the substratum beneath them the orientation of the deformations in flowtill is unrelated to the direction of glacial movement the shapes of some shears and folds are different in flowtill when compared with those in subglacial till and its substratum still the flow and shear structures alone are not sufficient to distinguish certain varieties of till fir instance subglacial primary till from flowtill but they are useful as local directional indicators of stress and as genetic criteria in combination with other features particularly with directional glacial erosion marks and fabric

pleistocene marine and periglacial deposits of the english channel the pleistocene marine and associated periglacial deposits of the coasts of southern england from cornwall to sussex the british channel islands and northern france from brittany and normandy to the pas de calais are described the deposition of almost all marine deposits is ascribed to temperate conditions although large igneous erratic boulders may have been emplaced by shore ice rafting at the end or beginning of cold stages the balance of the evidence from a variety of dating methods including u series dating amino acid geochronology and biostratigraphy of associated terrestrial formations indicates that deposits of the last three pre holocene temperate marine oxygen isotope stages stages 9 7 and substage 5e can readily be identified along much of both coastlines of the channel deposits attributable to stages 11 and 13 are uncommon and best seen in the staircase of marine terraces backing the hampshire sussex coastal plain and perhaps in western brittany and the boulonnais the height above modern sea level of the marine deposits is thought to be the result of slow uplift of the coastal zone caused by the isostatic response to sediment unloading during accelerated phases of erosion in cold stages although deep seated tectonics also may have been partly responsible for uplift however the height above modern sea level of a deposit alone is not on its own an indicator of age periglacial head deposits are mainly exposed along the coasts with the sections showing frost shattered debris moved downslope by cryoreptation frost creep the age of these deposits is uncertain although they appear to be principally of marine oxygen isotope stages 4 and 2 in age some remnants of marine oxygen isotope stage 6 or 8 head deposits are present both in england and northern france in a few places with good dating control head deposits dating to the marine oxygen isotope stage 12 can be recognised the age of the head deposits in most sections is based on their stratigraphical relationship with loess palaeosols and on the dating of the underlying raised beaches copyright 2003 john wiley sons ltd

till fabric associated with deformable beds this paper investigates the development of till fabric associated with glaciers overlying deformable beds first the till fabrics from both modern and ancient soft bed and hard bed subglacial environments are investigated and then soft bedded sites with specific strain histories are examined the results indicate that lodgement tills had a strong fabric whilst there is a wide range of much weaker fabric strengths associated with soft bed tills it is suggested from a theoretical study of soft bed till deposition that longitudinal and vertical processes in the subglacial deforming layer are important in fabric development field sites were chosen to isolate these two factors and fabrics investigated in areas of known relative shear strain and known relative thickness of the deforming layer the results indicate that 1 for a fixed deforming layer fabric strength does increase with increasing deformation except at very high strains where the development of a transverse fabric can lead to a reduction in the overall fabric strain and 2 lodgement tills and soft bed tills associated with a thin deforming layer have a high fabric strength whilst soft bed tills associated with a thick deforming layer have a low fabric strength where the deforming layer is thin clasts are oriented parallel with the glacier direction either by lodging against a hard bed or ploughing against a soft bed however where the deforming layer is thicker and shear strains are high melt out processes encourage a parallel fabric but the increased shear strain and changes in the deforming layer thickness cause the clasts to develop both a parallel and transverse fabric these processes combine to reduce the overall fabric strength till fabric studies are a further sedimentological technique to separate the depositional processes associated with a homogeneous till

neotectonics and glacial deformation in the karakoram mountains and nanga parbat himalaya abstract the karakoram mountains and the nanga parbat himalaya are one of the most rapidly rising mountain areas in the world with uplift rates in the order of 2 mm yr large scale regional warping is the most likely form of uplift with the greatest rates around the nanga parbat haramosh massif only two active faults have been recognised in the pakistan karakoram the rakhiot and the misgar valley fault the rakhiot fault zone is a neotectonic expression of the rapid uplift centred around the nanga parbat syntaxis deformation structures in quaternary and recent sediments in the rakhiot area are not produced solely by neotectonic processes but also by processes in the glacial depostional environment and slope related processes structures present vary from neotectonic shear zones folds thrusts and high angled faults glacially produced folds thrusts shears and joints and debris slides bounded by discrete shear zones the distinction between these structures is vital in making valid neotectonic models for high active mountain belts

coastal staircase sequences reflecting sea level oscillations and tectonic uplift during the quaternary and neogene many coasts feature sequences of quaternary and neogene shorelines that are shaped by a combination of sea level oscillations and tectonics we compiled a global synthesis of sea level changes for the following highstands mis 1 mis 3 mis 5e and mis 11 also we date the apparent onset of sequences of paleoshorelines either from published data or tentatively extrapolating an age for the uppermost purported oldest shoreline in each sequence including the most documented mis 5e benchmark we identify 926 sequences out of which 185 also feature holocene shorelines six areas are identified where elevations of the mis 3 shorelines are known and 31 feature elevation data for mis 11 shorelines genetic relationships to regional geodynamics are further explored based on the elevations of the mis 5e benchmark mean apparent uplift rates range from 0 01 0 01 mm yr hotspots to 1 47 0 08 mm yr continental collision passive margins appear as ubiquitously uplifting while tectonic segmentation is more important on active margins from the literature and our extrapolations we infer ages for the onset of formation for 180 coastal sequences sea level fingerprinting on coastal sequences started at least during mid miocene and locally as early as eocene whether due to the changes in the bulk volume of seawater or to the temporal variations in the shape of ocean basins estimates of eustasy fail to explain the magnitude of the apparent sea level drop thus vertical ground motion is invoked and we interpret the long lasting development of those paleoshore sequences as the imprint of glacial cycles on globally uplifted margins in response to continental compression the geomorphological expression of the sequences matches the amplitude and frequency of glacial cyclicity from middle pleistocene to present day moderately fast 100 000 yrs oscillating sea levels favor the development of well identified strandlines that are distinct from one another pliocene and lower pleistocene strandlines associated with faster cyclicity 40 000 yrs are more compact and easily merge into rasas whereas older cenozoic low frequency eustatic changes generally led to widespread flat lying coastal plains

tectonic eustatic and climatic significance of raised beaches of val de saire cotentin normandy france detailed mapping morphostratigraphical and geochronological analyses were undertaken in the val de saire cotentin normandy northern france these studies have identified a series of middle and upper pleistocene age deposits overlying four wave cut platforms pf iv pf i which can be associated with temperate high sea level events and equated with mis 11 9 7 and mi substage 5e a sea level stand recorded at 20 m ngf at the la mondree site seems to correspond to mi substage 5c or 5a the completeness of the val de saire record and particularly the width of platform iv mis 11 has so far no equivalent on the south coast of the english channel this study provides contribution to an understanding of the impact of the interglacial glacial cycles in a coastal intraplate situation the cyclicity of the morphogenesis is explained by interaction between eustatic variations and strongly expressed activity of slow uplift ca 60 mm kyr through the middle pleistocene several osl dates from the gravel to sand sequence of the eemian weichselian cycle indicate that these deposits represent the marine regression of the end of the last interglacial

pleistocene raised marine terraces of the spanish mediterranean and atlantic coasts records of coastal uplift sea level highstands and climate changes detailed geological mapping morphostratigraphic palaeontological and geochronological uranium series analyses were undertaken on the raised marine terraces and interbedded terrestrial deposits along the spanish peninsular and insular atlantic and mediterranean coasts several sets of pleistocene shallow marine to coastal deposits exposed in a staircase arrangement are interpreted as being emplaced during sea level highstands coeval with interglacials or interstadials correlating with marine oxygen isotopic stages ois 5a 5c 5e 7 9 11 and older up to three highstands have been identified in deposits formed during ois 5e close to the end of ois 5e there is a record of sudden changes in sea surface conditions and climate marked by the disappearance of a major proportion of the warm senegalese fauna switches from oolitic to non oolitic facies and accumulation of boulder beaches dating of the coral cladocora caespitosa found in a layer that also contains strombus bubonius confirms the occurrence of warm fauna in the mediterranean basin during ois 7 as previously suggested by hillaire marcel et al 1986 goy et al 1986a b zazo and goy 1989 also the occurrence of warm faunas in deposits corresponding to an older interglacial probably ois 9 or 11 in the balearic islands suggests similar oceanographic conditions sea surface temperature assuming constant salinity during the last interglacial and at least two interglacials of the middle pleistocene in the western mediterranean a 2002 elsevier science b v all rights reserved

whole rock aminostratigraphy and quaternary sea level history of the bahamas abstract the surficial geology of the tectonically stable bahamian archipelago preserves one of the most complete records of middle to late quaternary sea level highstand cycles in the world however with the exception of deposits from marine isotope substage mis 5e fossil corals for radiometric dating of this rich stratigraphic sequence are rare this study utilizes the previously published independent lithostratigraphic framework as a testing ground for amino acid racemization in whole rock limestone samples at least six limestone soil couplets provide a relative age sequence of events that encompass as many interglacial glacial cycles d alloisoleucine l isoleucine data fall into six clusters or aminozones on the basis of independent dating and the inferred correlation with global mis the ages of several aminozones are known while the ages of others are calculated from calibrated amino acid geochronology this study demonstrates the utility of the whole rock aminostratigraphy method for dating and correlating widespread emergent marine deposits constitutes the first regional geochronological framework for the bahamas and highlights major sea level events over the past half million years

melt out till in the edmonton area alberta canada till at two localities in the edmonton area alberta was formed mainly by passive melt out from glacier ice and not by lodgment by active ice or as a result of supraglacially derived flows this interpretation is based on the implications of in situ stratified glacial sediment below and within till and of large unlithified clasts of sediment derived from subtill deposits the interpretation is also supported by more general regional stratigraphic and structural observations such associated properties as subtill deformation a sharply planar till preglacial sediment contact sole marks and fabric support formation by melt out or illustrate local exceptions to this process regionally consistent preferred orientation of clasts is interpreted to represent preferred englacial orientation collective analysis of the principal eigenvectors of individual englacial fabrics and flow or resedimented till fabrics from a modem glacial environment and similar analysis for till at villeneuve near edmonton show the edmonton till to occupy the intermediate position in terms of orientation strength predicted by the melt out hypothesis in places preferred orientation is considered to have been disturbed by flow and diapirism induced by the process of thaw consolidation thus preferred clast orientation in till may show considerable deviation from a regional trend stratigraphy and sedimentology are used to classify the till and to relate individual exposures to regional environments of deposition

surface ocean temperatures in the north east atlantic during the last 500 000 years evidence from foraminiferal census data changes in north atlantic sea surface temperature sst are regarded as a key element of the climate during the quaternary however there are relatively few long term records providing quantitative sst estimates from this region using planktic foraminiferal derived ssts together with changes on species level and iceberg rafted debris the last 500 ka were studied pronounced sst changes as determined from the last glacial interglacial cycle characterize most colder periods peak interglacial temperatures were found for marine isotope stages mis 1 5e and 11 the latter two being the warmest the warm substages within mis 7 and 9 are marked by enhanced dissimilarity coefficients indicating that ssts obtained for these times appear to be overestimated this is corroborated by differences within the species assemblage which show enhanced cold water components it is therefore concluded that detailed analysis down to species level is a crucial prerequisite to better reconstructions of sst

late quaternary uplift rate inferred from marine terraces shimokita peninsula northeastern japan a preliminary investigation of the buried shoreline angle after estimating tectonic uplift rates along the northern part of the northeast japan forearc the overriding plate in the northeast japan subduction zone by mapping the elevation of the inner edges of marine terrace surfaces we refined this estimate through elevation measurements of the buried shoreline angle beneath well dated marine terrace surfaces from which we could derive more accurate paleo sea levels the uplift rate initially inferred from the inner edge of marine terrace t4 correlated with marine isotope stage mis 5e by tephrochronology increases eastward from 0 11 0 22 m ky 1 around the backarc volcanic front to 0 17 0 32 m ky 1 in the forearc on the peninsula of shiriyazaki we refined the uplift rates for t4 on the basis of the shoreline angle elevation from the reconstructed profile of the paleo sea cliff and wave cut platform on a rocky coast and the reconstructed profile of the swash zone sediments and terrace deposits on a sandy coast the refined uplift rates were 0 14 0 25 m ky 1 on the rocky coast and 0 14 0 23 m ky 1 on the sandy coast slightly slower than the rates we inferred from the height of t4 and about one half to three fourths of previously reported rates by extrapolation from the example of the sandy coast the refined uplift rate around the volcanic front was 0 09 0 18 m ky 1 the vertical deformation across the forearc of the shimokita peninsula since mis 5e is possibly associated with regional isostatic uplift of 0 09 0 18 m ky 1 and anticlinal deformation by an offshore fault interpreted from acoustic profiles of 0 05 0 07 m ky 1

a revised morpho and chronostratigraphy of the late and middle pleistocene coral reef terraces on southern barbados west indies the barbados coral reef terraces are one of the few type localities worldwide that provide insights into interglacial sea level change during the late and middle pleistocene several sea level estimates have been established since the late 1960s and each has contributed to the barbados model of sea level change this paper presents new morpho and chonostratigraphic data from the barbados coral reef terraces developed over the last 12 years the work is based on significant advances in electron spin resonance esr dating of fossil coral air photo interpretation and a greatly improved geomorphic map of preserved fossil beach formations and reef terraces above present sea level the need for a revision of past published morpho and chronostratigraphies is best demonstrated on the southern part of the island the morpho and chronostratigraphic sequence in this region is both more complex and diverse than has been assumed so far the revised morphostratigraphy presented here includes a differentiation of coral reef terraces wave cut platforms and other erosive features such as notches and cliffs our study of these geomorphic features combined with new numeric dating results esr u th enable a revised estimate of the spatial and temporal variation in tectonic uplift rate within south barbados these new rates are an essential requirement for more precise glacio eustatic sea level reconstructions during the late and middle pleistocene from this region

flow in the lower continental crust as a mechanism for the quaternary uplift of south east england constraints from the thames terrace record abstract the sequence of terraces of the river thames in south east england has been shown to date from the early pleistocene onwards and to provide an indication of the quaternary uplift history of the region using this evidence supplemented by altitudes of pliocene and early pleistocene marine sediments we have determined the pliocene and quaternary uplift histories of five representative localities clacton colchester and dartford for the lower thames and cookham and reading for the middle thames these uplift histories have been modelled using a physics based technique which calculates the isostatic response involving flow in the lower continental crust induced by cyclic loading at the earth s surface our results suggest that the late pliocene and early pleistocene part of the uplift history of our study region was initiated following the deterioration in climate starting at 3 1 ma which marked the start of upland glaciation elsewhere in europe the later increase in uplift rates in the middle pleistocene followed the start of intensified cyclic loading by very large continental ice sheets during and after oxygen isotope stage ois 22 at 0 87 ma dartford cookham and reading in the interior of south east england are all shown to have begun to uplift quite rapidly at rates of up to 0 1 mm a 1 following the start of forcing at 3 1 ma they have since uplifted by distances which increase gradually westward from 200 to 250 m of which a uniform 70 m has occurred since ois 22 at 0 87 ma in contrast clacton and colchester near the present north sea coastline experienced slow subsidence until the late early pleistocene but have nonetheless uplifted since ois 22 by similar distances to the other sites

dem and gis analysis of the stream gradient index to evaluate effects of tectonics the normandy intraplate area nw france computer based geomorphometry using a dem digital elevation model allows the analysis of the three dimensional properties of landscape this methodology is particularly useful in an intraplate region like western europe where the simple visual inspection of the topography cannot resolve the evolutionary trends of landforms in these domains the morphologies of the topographic surface may be controlled mainly by climate under a low rate of tectonic deformation among the geomorphometric parameters the stream length index sl has been used to characterize fluvial systems in relation to tectonics movements this work develops an algorithm to derive and map the sl index using a dem and gis to investigate its spatial variations in a broad area the algorithm is applied to a zone of weak intraplate deformation the coastal lowlands of normandy france the obtained spatial distributions of sl point to anomalous zones with high sl values these zones are adjacent to mapped fault scarps and characterized by changes in flow direction a kruskal wallis test shows that the bedrock lithology has no impact on the sl value therefore the sl variations can be related mainly to a differential uplift due to quaternary tectonic forcing quaternary sea level fluctuations may also be responsible for high sl values in a part of the coastal lowland

fluted moraine formation and till genesis below a temperate valley glacier slettmarkbreen jotunheimen southern norway clast fabric and morphological data have been used to determine the origin of fluted subglacial tills exposed by recent retreat of the slettmarkbreen glacier norway a new method for the interpretation of clast fabric data allows aspects of the strain and depositional history of the till to be reconstructed the till formed by a combination of lodgement and subsole deformation by slip along discrete shear planes lodgement was dominant for the larger size fractions 125 mm while the smaller material was more susceptible to deformation the fluted till surface reflects the tendency for the till matrix to deform into regions of low confining pressure in the lee of lodged boulders downglacier components of till flow are thought to have resulted in significant sediment transfer towards the margin

lithofacies types and vertical profile models an alternative approach to the description and environmental interpretation of glacial diamict and diamictite sequences abstract increased knowledge of modern glacial depositional environments has resulted in rapidly evolving classifications of glacial tills these are based to a large degree on theoretical considerations of likely depositional processes the classifications are sophisticated and more advanced than the establishment of simple field criteria whereby individual till facies can be identified in quaternary and pre quaternary successions this situation is compounded in many quaternary terrains by the continued description of tills in terms of laboratory derived analytical data only reflecting a traditional interest in stratigraphic correlation rather than reconstruction of depositional environment detailed sedimentological logging of lithofacies is rarely undertaken there is thus considerable confusion as to what is being described or sampled when analytical data are presented for many pleistocene tills the same remarks apply to pre pleistocene tillites a lithofacies code is presented here for the rapid description and visual appraisal of field sequences or drill cores containing unconsolidated diamicts or lithified diamictites the term till is not used as it has a strict genetic definition referring to direct aggregation and deposition by glacier ice use of a four part code in conjunction with codes already published for fluvial sediments allows fundamental field properties to be depicted independent of genetic terminology and provides a firm basis for subsequent environmental interpretation and analytical work the value of this approach is illustrated by comparing a representative suite of vertical profiles of diamict assemblages deposited by modern grounded glaciers with a classic late pleistocene glacigenic sequence at scarborough bluffs ontario

consolidation of sediments by glaciers relations between sediment geotechnics soft bed glacier dynamics and subglacial ground water flow a theory of subglacial consolidation is developed which shows how the meltwater flux beneath a glacier leaves a consolidation signature from which many important glacier dynamic properties can be inferred conditions under which water is discharged through channels or in a thin film at the ice bed interface or by ground water flow are discussed and it is concluded that glaciers flowing over aquifers of high transmissibility can induce deep circulation patterns quite different from non glacial circulation

uplift driven valley incision and river terrace formation in southern england outside the limits of middle pleistocene glaciation the river basins of southern england contain long cenozoic terrestrial sedimentary records of greatest importance are the river terrace sequences which contain biostratigraphical and sedimentary evidence that testifies to the high amplitude climatic changes of the quaternary however trends in valley development cannot easily be accommodated within the framework of quaternary climatic change it is argued in this paper that episodic incision and terrace development result from uplift a consequence of the interplay between continuing alpine orogenic movements and erosion driven isostasy using a simple linear model height age an uplift rate of ca 7 cm ka 1 is estimated for the terrace sequence in the upper thames valley this preliminary model is evaluated using the records of adjacent basins 1997 john wiley sons ltd

luminescence chronology of late pleistocene raised beaches in southern italy new data of relative sea level changes abstract littoral sediments forming terraces along the crotone peninsula coast southern italian have been investigated using sedimentological analysis and luminescence dating techniques and adopting assessments from previous work on fossil assemblages all sediment layers analysed were deposited in the nearshore environment between 20 m below and few metres above sea level during the falling sea level of a temperate warm climate interval the restoration of almost identical environmental conditions occurred in oxygen isotope substages 5e and 5a and in oxygen isotope stage 3 limits given by luminescence physics prevented accurate dating of the uppermost lying terrace former crotonian stage terrace and the presence of a substage 5c terrace is masked by the lack of suitable material for dating constraints on the positions of relative sea level from the reliable data set show that the sea level fell from 2 m during substage 5e to 29 m during substage 5a and then rose to 15 m during stage 3 observations for oxygen isotope stage 3 sea level at the crotone peninsula coast are inconsistent with those at the huon peninsula new guinea and in the western pacific the disagreement highlights the lack of knowledge concerning mediterranean thermohaline circulations and sea water exchanges between the atlantic and mediterranean seas during glacial cycles

stratigraphy and sedimentology of devensian dimlington stadial glacial deposits east yorkshire england the stratigraphy and sedimentology of the glacial deposits exposed along the coast of east yorkshire are reviewed critical sections at filey brigg barmston and skipsea are examined to reassess the stratigraphy of devensian dimlington stadial glacial deposits in the light of recent developments in glacial sedimentology sedimentary and glaciotectonic structures studied in the field and by using scanning electron microscopy are emphasised two hypotheses are considered for the genesis of the interbedded diamictons and stratified sediments the first involves the deposition of lodgement till and or deformation till followed by meltout till which was overridden to produce more deformation till reflecting periods of ice stagnation punctuated by glacier thickening the second hypothesis which is favoured on the basis of field evidence and micromorphology involves the vertical accretion of a deforming till layer associated with cavity channel or tunnel valley fills beneath active ice at barmston the upper part of the diamicton contains elongate pendant structures containing gravels indicating that the diamicton was saturated and able to flow the diamictons therefore represent a complex sequence of tills deposited and deformed by active ice during the dimlington stadial previously published stratigraphical schemes involving classifications of multiple tills in east yorkshire should be simplified and it is more appropriate to assign these to a single formation the skipsea till formation rhythmic glaciolacustrine and proglacial glaciofluvial sediments overlie the tills at barmston and skipsea these were deposited in sag basins during deglaciation as the tills settled and deformed under thickening sediment and as buried ice melted out extensive sands and gravels cap the succession and were deposited on a sandur during the later stages of deglaciation

active tectonics seismicity and geomorphology with special reference to normandy france integrated studies based on tectonic seismotectonic and geomorphological analyses indicate that normandy northwest france has been an active area during the quaternary topography and landform discontinuities reflect the dislocation and differential uplift of a late cenozoic platform the tectonic activity is represented by i active faults indicated by linear scarps and seismic activity ii offsetting of pre existing surfaces iii plio pleistocene sedimen tation restricted within narrow subsiding zones and iv morphometric properties of drainage basins that indicate zones of differential uplift the inferred strain pattern involves i a shortening direction that strikes nw se as expected in the european context of alpine compression and ii a ne sw trending extension accommodated by nw se normal faults the geomorphological systems encountered in normandy preferentially record differential vertical displacements copy right 2000 john wiley sons ltd

the timing of high sea levels over the past 200 000 years the 230 th ages and 234 u 238 u ratios were determined for barbados corals that grew during periods of high sea level within the last 200 000 years the similarity of the initial 234 u 238 u ratios of some of the corals to the modern marine value suggests that these samples are pristine and that the marine 234 u 238 u ratio 83 000 and 200 000 years ago was within 2 per mil of the modern value the accuracies of the 230 th ages are evaluated on the basis of the 234 u 238 u values and a model of the behavior of uranium and thorium isotopes during diagenesis for the last three interglacial and two intervening interstadial periods sea level peaked at or after peaks in summer insolation in the northern hemisphere this overall pattern supports the idea that glacial interglacial cycles are caused by changes in earth9s orbital geometry the sea level drop at the end of the penultimate interglacial the last interglacial and a subsequent interstadial period lagged behind the decrease in insolation by 5 000 to 10 000 years

interglacial sea levels abstract isotopic curves have been used as approximative estimators of global sea level calculations of the amplitude of sea level variations during interglacials especially for the last interglacial are based on the study of emerged coral terraces the application of different dating methods shows great uncertainty about the length of each interglacial and also about the number chronology and altitude of the different highstands that occur during each interglacial data of raised marine terraces from areas with different geodynamic behaviour bermudas bahamas peru chile italy and spain are summarized in order to analyze the relationships between sea level and interglacial stages two interglacials have been identified for the early pleistocene represented by two marine terraces with different highstands during the early middle pleistocene an interglacial with several highstands is recorded in uplifted areas during isotopic stage 11 at least one highstand with sea level equal or higher than present has been recorded similar sea level behaviour can be suggested for isotopic stage 9 all the analyzed areas record two highstands during isotopic stage 7 when warm equatorial fauna migrate into the mediterranean during isotopic substage 5e at least two highstands took place with evidence of lowstands between them and at least one highstand during substage 5c with similar sea level height above present msl except in barbados and bermuda during substage 5a at least one highstand has been recorded

accurate determination of the pleistocene uplift rate of the ne japan forearc from the buried mis 5e marine terrace shoreline angle abstract we used tephra and phytolith stratigraphy to refine pleistocene marine terrace chronology with reference to reported eustatic sea levels associated with the dated marine terraces and estimated uplift rates along the northern part of the northeast ne japan forearc the overriding plate in the northeast japan subduction zone by using elevation measurements of the buried shoreline angle beneath well dated marine terrace surfaces to derive more accurate paleo sea levels on the kamikita plain northernmost honshu island the t4 and t3 marine terraces were correlated to marine isotope stage mis 5e and mis 7c or 7e respectively by the stratigraphic positions of the tephras toya mis 5d and wp mis 7b the t2 terrace surface which had previously been assigned to mis 7 is buried by loess correlated to mis 8 by its phytolith assemblage therefore this terrace can be reasonably re correlated to mis 9 the reported optically stimulated luminescence ages for middle pleistocene terrace deposits tend to be younger than these refined terrace ages we used the buried shoreline angle elevation determined from the reconstructed profile of the marine terrace deposits and paleo sea cliff to refine the uplift rate of t4 since mis 5e the accurate rate thus determined 0 18 0 26 m ky is slower than the rates initially inferred from the inner edge of t4 but faster than the reported rate 0 14 0 19 m ky as recalculated here inferred from the assumed mis 5e shoreline elevation in addition it is roughly compatible with the rate inferred by using the top of t2 lagoon deposits to determine the shoreline elevation during mis 9 therefore during the last 300 ka the uplift rate of the kamikita plain has been constant at about 0 2 m ky this pleistocene uplift is probably attributable to a combination of moment release on the megathrust isostatic uplift driven by crustal thickening and reverse faulting of the upper crust

high resolution stratigraphic correlation of benthic oxygen isotopic records spanning the last 300 000 years abstract in order to compare the response of different oceanographic regions to global climate change very detailed stratigraphic techniques are required the global signal of ice volume changes recorded in the oxygen isotopic composition of foraminifera can provide the tool for developing the necessary high resolution stratigraphy in order to evaluate the resolution of a stratigraphy based on detailed isotopic records two techniques are used to correlate a set of benthic oxygen isotope records from seven piston cores taken in the north and south atlantic the indian and the equatorial and north pacific oceans the first technique was modified from the graphic correlation procedure of shaw 1964 this procedure requires the identification of isotopic events that are correlated from core to core detailed correlations for intervals of the cores between events are provided by a series of straight line segments connecting all common events the second technique developed by martinson et al 1982 uses inverse procedures to define a continuous non linear mapping function that correlates the isotopic records the mapping function maximizes the correlation coefficient between data sets being compared the techniques are independent in that they rely on different criteria for correlating the data series stratigraphic correlations obtained by these procedures are in excellent agreement the mean difference between the correlations is on the order of the sampling intervals of each core and when corrected for sedimentation rates suggests that benthic isotope records from the suite of seven cores can be correlated to a resolution of 2000 to 4000 yrs

the earliest occupation of north west europe a coastal perspective recent discoveries from pakefield and happisburgh britain have provided clear evidence for an unexpectedly early hominin occupation of north west europe the sites found in the deposits of interglacial rivers and estuaries on the southern rim of the ancient north sea coast span the older and younger parts of the cromerian complex stage the older of these sites pre date 0 5 ma based on the presence of a mimomys micromammal fauna and may be as old as 0 78 1 0 ma on the european continent stone artefacts unambiguously as old derive from the mediterranean the earliest archaeological evidence that has been discovered inland in europe north of the alps is associated with an arvicola fauna younger than 0 5 ma and was deposited in temperate conditions near rivers that flowed into the north sea only after the cromerian complex is there evidence for hominin activity in cooler conditions and also in locations east of the rhine valley this spatial and temporal pattern in site distribution occurs despite the long history of research in north west europe and the presence of deposits of the same age from both the coast and rivers this paper explores the idea that the changes in site distribution before and after the cromerian complex signal that early hominin occupation in northern europe during the earlier period was an atlantic phenomenon i e restricted to the milder temperate climates in the coastal continental regions dispersal to more inland habitats originated in the coastal regions the conditions explaining preservation of the oldest sites from a geological perspective are investigated providing a geographical climatological and habitat context for the wider surroundings of the sites because of differences in the potential for preserving archaeology in fluvial and coastal contexts poor long term preservation of coastal depositional contexts and low numbers of sites it is difficult to disentangle the influence of hominin habitat preference or even tolerance from habitat preservation however the hypothesis that the earliest hominins in europe were restricted to the temperate atlantic parts of europe provides a testable framework for evaluating future archaeological discoveries and makes it possible to formulate research strategies for locating new hominin occupation sites in europe especially its atlantic regions

an absolute chronology for the raised beach and associated deposits at sewerby east yorkshire england the raised beach sediments revealed in the cliffs at sewerby east yorkshire are widely regarded as ipswichian in age previously reported evidence for this dating is reviewed and new results from a range of luminescence dating techniques applied to the blown sand deposit overlying the raised beach are reported these provide the first absolute date for the sewerby site of 120 84 11 82 ka which places the blown sand at the boundary between oxygen isotope stages ois 5e and 5d as the underlying raised beach is little older than the blown sand it probably formed during ois stage 5e as suggested by the faunal evidence

comprehensive characterization of elevated coastal platforms in the north iberian margin a new template to quantify uplift rates and tectonic patterns abstract the cantabrian margin at the northern iberian peninsula shows elevated coastal platforms extending from west to east for 200 km these erosional surfaces are several kilometers wide and are bounded inland by a paleoshoreline and towards the sea by the retreating current cliff the origin and evolution of these geomorphologic markers remains controversial one of the main challenges arising from the difficulties in correlating the patchy distribution of the platforms and their variable heights along the margin due to lithological differences local tectonism and varying degrees of preservation with the aim of understanding recent coastal evolution a systematic quantitative gis analysis of lidar elevation models 5 m resolution was carried out along 4 000 km2 of the cantabrian coast between 4 15 w and 7 30 w longitude the coastline runs parallel to the cantabrian mountains which are supported by an orogenic root present only beneath the eastern half of the coastline under study the integration on the gis template of the crust mantle boundary as a controlling factor of landscape development has helped in the understanding of the recent evolution of the coastal platforms and in the interpretation of previously unexplained features of their distribution the two main outcomes of this multiscale approach are 1 the correlation of most of the fragmented rasas as part of an original unique coastal platform along the cantabrian margin and 2 the differentiation of two sectors separated by a highly tectonized area associated to the ventaniella fault the western sector has one main continuous surface showing a 0 08 tilt towards the west sometimes interrupted by local and recent minor faults with net slips of meters to tens of meters the eastern sector has several steps of erosional surfaces spread out at various heights without tilt the ventaniella fault separating both sectors produces an apparent vertical offset of 50 m in the main erosional surface our study shows that this fault also separates two distinct evolutions in the elevation of the coastal platform 1 the western coast which has risen continuously probably in response to a lateral gradient in crustal thickness and 2 the eastern coast where uplift is discontinuous over time since several of these surfaces formed below the main paleoshoreline the cantabrian coast captures the influence that crustal structure has on the expression and evolution of geomorphologic markers at the surface and vice versa landform features at the surface can be very sensitive to differential crustal thickness while responding to the same external and climatic forces in the context of the western european framework our work provides a regional template within which future absolute geochronological dating can be based to improve our knowledge of the recent evolution of the atlantic margins

the pleistocene rivers of the english channel region the pleistocene history of river systems that enter the english channel from northern france and southern england is reviewed during periods of low sea level cold stages these streams were tributaries of the channel river in southern england the largest the river solent is an axial stream that has drained the hampshire basin from the early pleistocene or late pliocene other streams of southern england may be of similar antiquity but their records are generally short and their sedimentary history have been destroyed as in northern brittany by coastal erosion and valley deepening as a consequence of tectonic uplift in northern france the seine and somme rivers have very well developed terrace systems recording incision that began at around 1 ma the uplift rate deduced from the study of these terrace systems is of 55 to 60 m myr 1 since the end of the early pleistocene generally the facies and sedimentary structures indicate that the bulk of the deposits in these rivers accumulated in braided river environments under periglacial climates in all the area around the channel evolution of the rivers reflects their responses to climatic change local geological structure and long term tectonic activity in this context the middle somme valley is characterised by a regular pattern in which incision occurs at the beginning of each glacial period within a general background of uplift nevertheless the response of the different rivers to climatic variations uplift and sea level changes is complex and variable according to the different parts of the river courses copyright 2003 john wiley sons ltd

high level shore features of jersey channel islands and adjacent areas abstract past marine surfaces occur between present low tide and 45 m mean sea level msl in the channel islands and along adjacent french coasts particularly on jersey a detailed historical review of the early work concerned with the mapping of the range of marine surfaces is supported by detailed levelling surveys including a new one of the cove of le pulec in jersey the importance of the very large tidal ranges in parts of the area that between guernsey and the baie du mont saint michel being the largest in the world for relatively open sea is shown to have an effect on the height range of present and former sea levels this information is applied to make estimates of past tidal ranges related to the outcrop evidence of the high marine surfaces the survey results are applied to develop a sequence of high marine surfaces which differ in some important respects from those published to date for both the channel islands and adjacent french coasts discussion of the factors that may affect the altitude and age of the marine surfaces includes consideration of the current debates surrounding the origins of the uplift whether of purely neotectonic or combined neotectonic and climatically induced factors

rapid sea level changes at the close of the last interglacial substage 5e recorded in bahamian island geology rapid and abrupt relative sea level changes within the last interglacial substage 5e are recorded in the island geology of the tectonically stable bahamas from 132 to 118 ka reef growth reached a maximum elevation near 2 m as indicated by fossil reef elevation across the platform whereas bioeroded notches are incised in coastal cliffs as high as 6 m the end of the interval is characterized by voluminous eolianites exhibiting palm tree and frond impressions it is inferred that sea level for most of the interval remained near 2 m restraining reef growth and that the notch at 6 m represents a rapid and brief excursion just before the close of the substage the subsequent fall must have been rapid in order to leave the notch profile intact and mobilize windward lagoon ooids into dunes before cementation could anchor them in order to explain the rapid rise to 6 m glacial surging is invoked the subsequent fall also rapid may be a consequence of the surge flooding high latitudes and providing enough moisture to initiate reglaciation and drawdown

sea level and deep water temperature changes derived from benthic foraminifera isotopic records we show that robust regressions can be established between relative sea level rsl data and benthic foraminifera oxygen isotopic ratios from the north atlantic and equatorial pacific ocean over the last climatic cycle we then apply these regressions to long benthic isotopic records retrieved at one north atlantic and one equatorial pacific site to build a composite rsl curve as well as the associated confidence interval over the last four climatic cycles our proposed reconstruction of rsl is in good agreement with the sparse rsl data available prior to the last climatic cycle we compute bottom water temperature changes at the two sites and at one southern indian ocean site taking into account potential variations in north atlantic local deep water 18o our results indicate that a last glacial maximum lgm enrichment of the ocean mean oxygen isotopic ratio of 0 95 is the lowest value compatible with unfrozen deep waters in the southern indian ocean if local deep water 18o did not increase during glacials with respect to present such a value of the lgm mean ocean isotopic enrichment would impose a maximum decrease in local bottom water 18o at the north atlantic site of 0 30 during glacials

relative sea level fall since the last interglacial stage are coasts uplifting worldwide the growing interest in quantification of vertical ground motion stems from the need to understand in detail how the earth s crust behaves for both scientific and social reasons however only recently has the refinement of dating techniques made possible the use of paleoshorelines as reliable tools for tectonic studies although there are many local studies of quaternary vertical motions of coastlines we know of no comprehensive worldwide synthesis here we provide a compilation of 890 records of paleoshoreline sequences with particular emphasis on the last interglacial stage marine isotopic stage mis 5e 122 ka the quality of dating mis 5e makes it a reliable marker to evaluate vertical ground motion rates during the late quaternary on a global scale the results show that most coastal segments have risen relative to sea level with a mean uplift rate higher than 0 2 mm yr i e more than four times faster than the estimated eustatic drop in sea level the results also reveal that the uplift rate is faster on average for active margins than for passive margins neither dynamic topography nor glacio hydro isostasy may explain sustained uplift of all continental margins as revealed by the wide distribution of uplifted sequences of paleoshorelines instead we suggest that only plate tectonic processes reconcile all observations of quaternary coastal uplift we propose that long term continental accretion has led to compression of continental plates and uplift of their margins therefore this study concludes that plate tectonics processes impact all margins and emphasizes the fact that the notion of a stable platform is unrealistic these results therefore seriously challenge the evaluation of past sea levels from the fossil shoreline record

sea level highstands over the last 500 000 years evidence from the ironshore formation on grand cayman british west indies abstract the ironshore formation up to 19 m thick in the rogers wreck point area of grand cayman is divided into the unconformity bounded units a b c and d the unconformities are highlighted by caliches and or terra rossa th u dates from aragonitic corals indicate that unit a formed at 400 ka unit b 346 ka unit c 229 ka and unit d 131 ka these ages correlate with the highstands of the last four interglacial periods and probably represent marine isotope stages 5 unit d 7 unit c 9 unit b and 11 unit a the limestones in units a d which have similar biotic and lithologic characteristics represent deposition in shallow water on a narrow coastal shelf unit a has a high faunal diversity and was deposited in open marine conditions whereas units b c and d were deposited in quieter water lagoons that probably had fringing reefs along their sea ward edges although grand cayman is located on the cayman ridge close to an active spreading center and transform fault the island has undergone little or no vertical movement over the last 500 ky available evidence indicates that sea level at the time of deposition of each unit relative to present sea level was unit a 9 0 to 5 5 m unit b 3 0 to 0 5 m unit c 2 5 to 1 1 m and unit d 2 5 to 6 0 m these data are good estimates of eustatic sea level highstands over the last 500 ky