environmental impacts of baltim and ras el bar shore parallel breakwater systems on the nile delta littoral zone egypt this study evaluates the impacts resulting from the construction of two large scale detached breakwater systems on the nile delta coast of egypt at baltim and ras el bar beaches 18 3 km shoreline length the two protective systems were installed in a water depth of between 3 and 4 m and consist of 17 units in total each 250 m long a comprehensive monitoring program spanning the years 1990 to 2002 was implemented and included beach nearshore profiles grain size distribution of seabed sand and information related to the background coastal processes evaluation of these systems concentrates on the physical impacts on coastal morphodynamics mitigation and their design implications the beach and nearshore sedimentation erosion accretion patterns and grain texture of seabed sediment in the study areas have been substantially disrupted due to the interruption of longshore transport by the shore parallel detached breakwaters rate of shoreline and seabed changes as well as alongshore sediment volume have been substantially affected resulting in accretion in the breakwater landward sides tombolo or salient followed by downdrift erosion the preconstruction beach erosion at baltim 5 m year and at ras el bar 6 m year has been replaced respectively by the formation of sand tombolo 35 m year and salient 9 m year on the other hand beach erosion has been substantially increased in the downdrift sides of these protective systems being 20 m year at baltim and 9 m year at ras el bar further seaward the two protective systems at baltim and ras el bar have accumulated seabed sand at maximum rates of 30 and 20 cm year and associated with downdrift erosion of 45 and 20 cm year respectively strong gyres and eddies formed in the breakwater gabs have drastically affected swimmers and subsequently caused a significant number of drownings each summer averaging 35 and 67 victims year at baltim and ras el bar beaches respectively this study provides baseline information needed to help implement mitigation measures for these breakwater systems

paleoseismology along the southern kuril trench inferred from diatom based sea level reconstructions 1 2 3 3 400 500 1

diatom records and sedimentary responses to sea level change during the last 8000 years in roudsea wood northwest england diatom biostratigraphies are recorded in close stratigraphical intervals from two sites in roudsea wood northwest england these diatom sequences are used to reconstruct sediment surface elevation which is then compared with the mid and late holocene sea level history of the region four new sea level index points are added to the sea level data base for the region and the sea level history is subjectively divided into three time periods for discussions the established model of sediment surface elevation for roudsea wood suggests that the sedimentary responses to the changing sea level have varied through time and appeared as site dependent in roudsea wood valley a site sheltered from the estuary the sedimentary equilibrium was not reached until the end of the first period around 6200 yr bp coincided with the development of a sand barrier across the mouth of the valley in roudsea marsh a site opened to the estuary the sedimentary equilibrium was reached as late as the end of the second period aro

processes of selective grain transport and the formation of placers on beaches placers are found on many beaches of the oregon coast in the beach that is the focus of this study the principal placer minerals are ilmenite 22 0 epidote 20 0 garnet 18 7 augite 15 5 hypersthene 8 1 hornblende 5 8 and zircon 2 0 the ilmenite fraction actually being partly chromite a series of beach face sand samples was obtained along a profile when sand was being eroded from the upper beach and transported to offshore bars since the processes of grain selective sorting leading to placer formation were probably most active at such a time the landward most sample contained 96 heavy minerals being part of the placer this concentration systematically decreased offshore to a 6 heavy mineral content in the seaward most sample 54 m offshore determinations of individual heavy mineral concentrations revealed that although they all tended to become concentrated within the placer with light quartz and feldspar dominating the offshore transport the sorting processes were m

holocene relative sea level change and rate of sea level rise from coastal deposits in the toyooka basin western japan this study presents relative sea level rsl change from 11 200 to 500 cal bp in the toyooka basin western japan diatom assemblage and sedimentary sulfur analyses were performed for 32 sediment

nature and human impact on nile delta coastal sand dunes egypt this paper deals with the types distribution and origin of recent sand dunes in the coastal sector extending between el burullus lake and the damietta nile river branch egypt sand samples were studied for grain size distribution and mineralogical composition it has been found that most of the dunes in the study area have been subjected to deterioration and removal due to the construction of summer resort buildings and making the international coastal highway the remnant constitutes a belt of foredunes on the shore of baltium extending westward to burg el burullus village

detecting temporal shoreline changes and erosion accretion rates using remote sensing and their associated sediment characteristics along the coast of north sinai egypt the variation during 15 years in the shoreline along the north sinai coast has been determined by analysing tm and etm true colour landsat images from 1986 to 2001 the analyses identified erosion and accretion patterns along the coast the shoreline has advanced west of el bardawil inlet1 el bardawil inlet2 and el arish harbour where the wave induced littoral transport has been halted by jetty construction and beach growth rates are 20 681 69 855 and 20 160 m2 year respectively on the downdrift side of the constructed jetties to the east the shoreline is retreating and beaches erode at rates of 71 710 69 968 and 11 760 m2 year respectively sedimentological analyses of beach sediment samples have indicated selective transport of heavy minerals according to their densities and grain sizes a general correspondence has been found between variation in grain size sorting and heavy mineral content of beach sand and the patterns of shoreline changes

the stratigraphy depositional environment and dating of a possible tidal surge deposit in the beauly firth area northeast scotland the stratigraphic setting pollen and diatom content and radiocarbon age of a thin minerogenic layer predominantly composed of grey micaceous silty sand are described from two sites located near the head of the beauly firth scotland the layer resulted from a short lived incursion of marine water which flooded subtidal intertidal saltmarsh and reedswamp environments during the mid holocene comparisons with other sites in eastern scotland indicate this incursion may have been caused by a north sea storm surge event of considerable magnitude

spatial and temporal variability of titanomagnetite placer deposits on a predominantly black sand beach abstract titanomagnetite forms rich placer deposits along the northwest coast of new zealand these deposits were sampled along 3 shore normal transects spaced over the southern 2 km of a dissipative high energy beach on the west coast in 5 field campaigns covering one year the percentage of opaque minerals mainly titanomagnetite was extremely high in the upper 30 m of the beach face extending seaward where these opaque minerals were gradually replaced with variable amounts of lighter augite hornblende and plagioclase the pattern appeared to be divided into two regions a lower seaward and an upper landward region separated by a point where either marine dominated over aeolian processes or where swash dominated over breaking processes in the seaward region the percentage of opaques increased and particle size fined landward as undertow removed the lighter larger particles seaward in the landward region the percentage of opaques and particle size were more constant or even showed the reverse pattern as wind transported the lighter material shoreward or swash asymmetry transported the heavier material seaward the similarity of settling velocities over the whole beach face suggests that sorting by size rather than weight plays a dominant role in separating the mineral assemblages considerable variations existed between transects this could be explained by the spatial changes in surfzone waves and currents that were associated with proximity to the southern headland and various rip current channels that characterised this dissipative site surprisingly the percentage of opaques decreased when the wave conditions of the day of sampling were more energetic in contrast to many other placer deposits these deposits are abundant on the beach face forming an armouring layer during lower wave energy conditions during higher wave conditions the surface layer erodes allowing lighter augite plagioclase and hornblende to be released from the sediments below

patterns of erosion sedimentation heavy mineral concentration and grain size to interpret boundaries of littoral sub cells of the nile delta egypt abstract analyses have been undertaken of 68 beach nearshore profiles spanning the years 1971 1995 to interpret sub littoral cells of the nile delta that developed during cross shore and alongshore sediment transport bottom sediments of these profiles taken along the 240 km length of the delta coastline have been analyzed to determine seabed level changes textural and heavy mineral concentration distributions the spatial distribution of seabed depth changes linked with the heavy mineral concentration allows identification of three zones of erosion source areas associated with accretion sink areas erosion zones occur off the nile promontories at rosetta 20 to 50 cm yr burullus and damietta 0 to 20 cm yr accretion ranging from 0 to 40 cm yr occurs between erosion zones at abu quir bay the rosetta saddle gamasa embayments and along the western side of the jetty at the suez canal entrance port said this pattern was generally induced from the temporal variability in the direction and intensity of the incoming waves currents orientation of coastline seafloor morphology and local protective structures the correspondence among patterns of seabed depth change heavy mineral concentration and to some extent the texture of seabed sediments refine boundaries of littoral sub cells of the nile including sediment paths sources sinks nodal points and zones of sediment transport convergence and divergence this correspondence is not strongly correlated as might be expected in this deltaic system where sediment has been recycled between recent and relict seabed settings moving in the alongshore and cross shore directions nevertheless the present investigation shows that the relationship between seabed level changes heavy mineral concentration and to some extent mean grain size of the littoral zone can be practically applied in other deltaic settings to interpret sediment transport pathways particularly where there are less relict sediments

mineralogy of the pennsylvanian coal seam in the datanhao mine daqingshan coalfield inner mongolia china genetic implications for mineral matter in coal deposited in an intermontane basin abstract this paper deals with the mineral matter in the coal and associated strata from the datanhao mine daqingshan coalfield which is closely located to the previously reported adaohai and hailiushu mines of the same coalfield the coal from the datanhao mine is mainly high ash and low sulfur bituminous the mineral assemblage in the coal is dominated by quartz kaolinite with varying proportions of carbonates calcite ankerite and siderite small proportions of muscovite illite pyrite and anatase the associated non coal claystone samples have similar mineral assemblage except that most non coal samples contains less quartz than the adjacent coal plies although deposited in the same intermontane basin of the orogenic belt the yinshan upland the datanhao coal seam shows different mineralogical characteristics from those of the nearby adaohai and hailiushu mines this may reflect the different sediment source regions during the peat accumulation stage the sediment source for the datanhao coal was probably the ordovician quartz rich sandstone or the sinan quartzite in the surrounding sub uplifts high proportions of quartz in the datanhao coal suggest intense terrigenous input into the paleomire and a short distance from the sediment source region different mineralogical characteristics of the coals from the three mines datanhao hailiushu and adaohai of the daqingshan coalfield are probably due to the different source material in their respective surrounding subuplifts within the intermontane basin kaolinite displaying graupen tabular and vermicular textures and the common presence of quartz in the intra seam non coal bands from the datanhao coal seam indicate that most of these bands are tonsteins altered airborne volcanic ash the original magma is probably high level volatile rich silicic in composition

synsedimentary volcanic ash derived illite tonsteins in late permian coal bearing formations of southwestern china abstract illite claystones tonsteins of late permian coal bearing formations are well developed and extensively distributed in southwestern china over the past decades it has been recognized that they are synsedimentary volcanic ash falls in origin altered tuff beds based on the data derived from the comprehensive investigations on their stratigraphic and geographic distribution petrographic types chemical composition accessory mineral assemblage as well as on their morphological characteristics recently mineralogical and petrological identifications and x ray diffraction analyses on these peculiar tonsteins further suggest that they can be classified mainly into three categories based on their clay mineral constitution kaolinitic kaolinitic illitic transitional type and illitic as coal partings in most cases these different types of tonsteins show a distinct zonal distribution on a regional scale their mineral constitution is profoundly modified by the combined effects of many factors during deuterogenic diagenesis as indicated by the variation in volatile component percentage vm of the adjacent coal seams vm is calculated on a combustible component basis those tonsteins intercalated in coal with a vm 10 are dominated by kaolinite but they contain increasing amount of illite at the expense of kaolinite when vm of coal decreases from 10 to 8 when vm declines to less than 8 the clay minerals in these tonsteins are almost entirely illite with some sort of accompanying chloritization it is clear that from a regional point of view the variation in clay mineral constitution of these tonsteins is in response to the continual and progressive change in geological processes in addition to the temperature and pressure conditions the existence of a certain amount of alkali metal ions and ferrous ions in solution is one of the controlling factors

shoreline changes along the rosetta nile promontory monitoring with satellite observations abstract a study to test the effectiveness of satellite data for monitoring shoreline change is reported the rapidly changing rosetta promontory of the nile delta egypt being selected as the study area landsat multispectral scanner mss image data in the near infrared 0 8 1 1 m 80 m resolution covering a 15 year period 1972 1987 at roughly 3 year intervals were compiled these were digitally overlain registered and differenced relative to the initial 1972 shoreline and composite changes erosion and accretion are mapped the area studied is one undergoing both aggradation and degradation depending on location sediment supply and man made barriers it was found that the general trend of the regional processes can be monitored with landsat imagery due to its repetitive coverage and good spectral contrast of land and sea improved satellite imagery with higher resolution should be a valuable tool for complementing traditional shoreline monitoring surveys in easily eroded lowlying areas such as the nile delta

late holocene land and sea level changes in the british isles implications for future sea level predictions abstract four decades of palaeosea level research in the british isles have produced a large dataset of age altitude curves of postglacial sea level changes patterns of late holocene relative sea level change reveal the persistent influence of the british irish ice sheet and the larger scandinavian ice sheet on contemporary rates of vertical land movements the shennan and horton 2002 map of late holocene relative land movements has been used in future sea level rise predictions by the united kingdom climate impact programme in their 2002 assessment ukcip02 but has been mistaken for a map of absolute land movements in this paper land motion data for britain are extracted from the shennan and horton 2002 relative sea level data and a new map of crustal land movements is presented which also includes ireland this procedure takes into account the regional 20th century sea level rise 0 14 m and the process of ocean syphoning i e a global fall in sea level of 0 3 mm yr due to gia induced ocean floor lowering and re distribution of ocean mass the calculated land motion rates also depend on the global late holocene ice equivalent sea level change given by the intergovernmental panel on climate change as 0 0 0 2 mm yr accounting for these processes reduces the misfit between geological observations of vertical land motion and those independently derived from gravity aligned global positioning system ag gps measurements and shows that ukcip02 has underestimated land subsidence in southern britain and over estimated land uplift in scotland both by 0 1 0 2 mm yr a best fit between gps and geological estimates of land movements in britain is achieved for a global long term eustatic sea level fall of ca 0 2 mm yr suggesting some global ice expansion in the late holocene rather than melt if this is correct uplift rates in scotland would be lower and subsidence rates in southern britain would be faster by 0 4 0 5 mm yr than estimated by ukcip02 more high quality late holocene relative sea level data are required to quantify vertical land motion as accurately as possible especially near large coastal population centres for input into regional scenarios of future sea level rise

recent morphological changes of the yellow river huanghe submerged delta causes and environmental implications abstract the yellow river huanghe submerged delta yrsd has been under the threat of erosion and retreat during the anthropocene due to dramatic climatic and anthropogenic changes in the yellow river basin the analysis of field data shows that over the period of 1977 2005 the changes in climate decrease in precipitation and increase in air temperature and human interventions increase in water diversion projects throughout the watershed have resulted in the sharp reductions of river flow and sediment discharges into the bohai sea consequently over the decadal timescale morphological evolution of the yrsd has gone through three stages i e rapid accumulation 5 77 10 8 m 3 year in 1977 1985 moderate accumulation 3 80 10 8 m 3 year in 1986 1995 and slow accumulation 0 91 10 8 m 3 year in 1996 2005 climatic change within the catchment characterized by the rapid increase of air temperature contributed significantly to the transitions from the rapid accumulation to the moderate accumulation and to the subsequent slow accumulation the decadal morphological changes of the yrsd also show peculiar deposition erosion characteristics over the medium timescale under river input reduction within the three decades the patterns of the main sedimentary body exhibit irregular ellipses with the long axis parallel to the 5 or 10 m isobaths and short axis perpendicular to the isobaths the depocentres of the yrsd are located between the 10 and 15 m isobaths close to the respective river mouths with a high vertical accretion rate of 1 20 m year the time series data of annual volumetric change of the yrsd and river sediment load from 1977 to 2005 further demonstrate significant linear positive relationships between deltaic geomorphic change and fluvial input over shorter timescales annual and 3 year the critical sediment discharges for maintaining the deposition erosion equilibrium state of the yrsd over the annual and 3 year timescales are found to be 1 79 10 8 t year and 1 29 10 8 t year respectively the analysis from the latest hydrological data 2006 2015 suggests that over the decadal timescale the evolution state of the yrsd currently has transitioned from constructive to destructive due to the weakened fluvial input moreover there exists a close quantitative link between the progradation of the yellow river subaerial delta yrad and the yrsd over the five year timescale indicating that every 1 10 8 m 3 year increase of the yrsd s yearly volumetric change will result in a 3 28 km 2 year increase of the yrad s yearly land accretion area and the yrad will reach the extension retreat balance state when yearly morphological change of the yrsd is at 0 73 10 8 m 3 year

evolutionary trends of the niger delta shoreline during the last 100 years responses to rainfall and river discharge article there is growing evidence that the world river deltas are influenced by climate change and anthropogenic activ ities in this study shoreline changesalong the niger delta coastofthegulf ofguinea northatlanticoceaninthe last ten decades were investigated the relationships between these changesand hydrometeorologic variables of rainfall and river discharge were considered topographic maps and satellite imagery in addition to rainfall and hydrological data from the lower niger river basin were used for the study the results show two distinct shoreline dynamics patterns phases first mobility with high net retreat between 1923 and 1987 interval and second mobility with low net progradation from 1987 to 2013 during the first phase shoreline retreat is mainly concentrated on the western and arcuate sections of the delta in the second phase all sections of the niger delta coast prograded seaward strong correlations between shoreline change and the river discharge r 2 0 95 shoreline change and rainfall variability r 2

implications of delta retreat on wave propagation and longshore sediment transport guadalfeo case study southern spain abstract the influence of both natural and human induced changes on the evolution of worldwide deltas has been widely addressed however the variations of the submerged morphology of the delta and their implications on coastal dynamics have received limited attention this work details the spatial and temporal variability of the mouth of the guadalfeo river southern spain and focuses on the influence of submerged morphological changes partly due to watershed regulation in 2004 on wave propagation and longshore sediment transport bathymetric measurements were carried out over a 15 year period 1999 2014 a wave propagation model was calibrated and applied and an updated expression for longshore sediment transport was applied using downscaling techniques to obtain the complete littoral drift time series the results show that the river damming led to coastline retreat and bed level erosion up to 3 m along a 1 km section around the river mouth with maximum erosion rates in excess of 760 m 3 m these subtidal morphological changes reduced wave refraction and led to higher breaking wave energy variations in wave climate during the study period have also played a role in influencing the coastline dynamics although the erosion around the river mouth has decreased since 2008 partly due to a sediment pulse in 2010 eastward longshore sediment transport rates under westerly storm wave conditions have significantly increased since then this has led to the propagation of the sediment deficit towards the east of the mouth endangering urban developments at this location this paper provides insights into the shift from wave river dominated deltas towards deltaic coasts increasingly controlled by wave directionality and longshore sediment transport and represents an advance on the understanding of the dynamics of many worldwide deltas where the river sediment supply has decreased due to human activities

erosion of a sandy coast continuous follow up of the coastal groynes of protection in boumerdes algeria the waterfront of boumerdes saw a development in 2005 which consisted of the construction from west to east of two groynes perpendicular to the coast and a shaped spike of t further east these groynes of 50 m in length are constructed of concrete in the middle of the building and are protected by rockfill blocks of metamorphic rocks type our aim is to control the work and make a complete sedimentological study to determine the different sources of sediment supply to follow their distribution at the beach and finally to know the particle trapping zones along the coastal geomorphological entity between boumerdes stream and corso stream before and after the construction of these groynes we have determined fattening areas or depletion sand erosion along the beach which is followed since 1986 we also used heavy minerals as natural tracers to determine the transit directions of sediment supply reaching the study area and their deposition this study will draw up a report on the functioning of the groynes and make a correction in some areas with high risk of erosion after the construction of the groynes

spatial variations in heavy minerals and patterns of sediment sorting along the nile delta egypt abstract sand samples were collected along 34 beach profiles spanning the 240 km length of the nile delta in order to examine the sorting patterns of heavy minerals that develop during cross shore and alongshore sediment transport factor analysis of the heavy mineral contents shows that two mineral factors or groups result from sorting due to the contrasting densities and sizes of the grains one factor is dominated by augite hornblende and epidote while the second factor consists of opaques garnet zircon rutile and monazite minerals of factor 1 are of lower densities and coarser sizes and represent the grains that are selectively entrained by waves and currents in areas of beach erosion and preferentially transported to zones of beach accretion where they are deposited the higher density minerals of factor 2 tend to become concentrated in areas of beach erosion accounting for the formation of black sand placers where the erosion has been greatest the spatial distributions of these two factors reflect the grain sorting patterns of the heavy minerals which coincide with the general trends of shoreline erosion versus accretion that exist along the length of the delta there is also a distinctive pattern of cross shore sorting with factor 2 containing the denser minerals being best developed within the inner surf zone generally with a maximum at the shoreline its development corresponds to the formation of black sand concentrates on the beach face where erosion has been greatest implying that grain sorting has taken place mainly within the swash zone there is a general decrease in factor 2 relative to factor 1 toward the offshore often with oscillations that are congruent with the beach topography factor 1 with the lower density minerals is greatest over offshore bars where deposition has prevailed

abu quir bay a sediment sink off the northwestern nile delta egypt abstract sectors undergoing erosion and or sediment accretion in abu quir bay off the northwestern nile delta egypt are identified by distribution patterns of grain size carbonate content and heavy minerals in beach and surficial bay and shelf samples these data are used to interpret sediment dispersal patterns and to provide information on provenance of recent and relict sediments including those from the canopic distributary the canopic is a former major nile distributary which once flowed in the western part of abu quir bay heavy mineral suites comprising opaques hornblende epidote garnet and zircon are concentrated in areas subject to erosion including the rosetta promontory abu quir headland and the idku lagoon inlet the latter is close to the mouth of the former canopic branch proportions of these minerals diminish away from high energy zones and toward the center of abu quir bay conversely proportions of augite increase toward the center of the bay distributions of texture carbonate content and heavy minerals indicate sediment dispersal by both contour following bottom and cross shelf seaward trending currents petrologic patterns define flow divergence away from high energy along the bay margins and areas of flow convergence toward the center of the bay and northward on the shelf textural and mineralogical distributions are attributable to processes that erode the mouth of the modern rosetta branch transport carbonate sediments derived from the abu quir carbonate ridge and rework relict sediment from the former canopic channel and its subdelta transport patterns interpreted on the basis of petrology complement information determined from measurement of bottom currents and longshore transport together this information indicates that much of modern abu quir bay is a sediment sink on the nile delta margin

beach response to a sequence of extreme storms abstract a sequence of daily beach surveys acquired over one month covering an area larger than 100 000 m 2 was analyzed to study morphological changes resulting from a cluster of storms the beach response was highly variable in both the cross and alongshore a cumulative storm effect was not observed despite one storm being characterized by a 10 year return period that had significant wave height h s of 8 1 m and a peak wave period t p of 17 s instead storms that can potentially cause significant erosion in terms of h s had a limited effect on the morphology because the large wave height was coupled to either neap tides normally incident short waves f 0 04 hz or low levels of infragravity 0 004 f

evolution of the modern nile delta promontories development of accretional features during shoreline retreat the active accretional features that have developed along the modern nile delta promontories during shoreline retreat are analysed using topographic maps remote imagery ground and hydrographic surveys together providing 15 time slice maps 1922 2000 at rosetta and 14 time slice maps 1909 2000 at damietta small double sandy spits developed and persisted at rosetta between 1986 and 1991 at damietta a much larger single spit 9 km long formed approximately east of the mouth of the damietta nile branch between 1955 and 1972 although its source has now been depleted both the rosetta and damietta inlets are associated with submerged mouth bars that accumulated prior to the damming of the nile but that continue to contribute to local sedimentation problems particularly at rosetta the development of the active accretional features along the nile promontories reflects a combination of factors including sediment availability transport pathways from source areas a decrease in the magnitude of nile flood discharges as well as the impact of protective structures at the river mouths

la icp ms u pb dating of carboniferous ash layers in the cantabrian zone n spain stratigraphic implications seven centimetre thick volcanic ash fall layers interbedded within the thick carboniferous successions of the cantabrian zone in northern spain were dated by u pb zircon laser ablation inductively coupled plasma mass spectrometry across an interval ranging from visean to kasimovian thus covering most of the carboniferous period all these ash layers occur in fossiliferous successions allowing us to insert the radiometric data within a well constrained biostratigraphic framework considering the analytical uncertainty the obtained ages match the ages inferred from the conodont biostratigraphy established in the mississippian succession which hosts the oldest two ash layers visean in age and the fusuline and mega and microflora data from the strata hosting the moscovian and kasimovian westphalian stephanian tonsteins the age of a langsettian tonstein along with data provided by several papers stating that in the cantabrian zone langsettian floras were contemporaneous with lowermost moscovian fusulines suggest that langsettian floras could have been younger in spain than in other areas our absolute ages provide new constraints not only for the correlation of the carboniferous successions of the cantabrian zone with time equivalent reference successions in other parts of the world but also for calibrating the carboniferous global chronostratigraphic units based on marine fossils with the west european regional units supplementary material stratigraphic position and biostratigraphic information on the studied ash fall layers analytical methods and geochronological results are available at https doi org 10 6084 m9 figshare c 3768701

patterns of isostatic land uplift during the holocene evidence from mainland scotland preliminary results of a lengthy and detailed investigation into middle and late holocene raised shorelines in mainland scotland indicate that three shorelines are sufficiently widely distributed to permit an examination of their extent and of the patterns of uplift which they indicate the shorelines are the storegga tsunami shoreline reached at c 7100 14c years bp at the culmination of the main postglacial transgression and the blairdrummond shoreline reached after the main postglacial shoreline at c 2000 4200 14c years bp at the time of a tsunami believed to have been caused by the second storegga submarine slide the main postglacial shoreline reached at c 5800 6850 14c years bp the main postglacial shoreline previously believed to be the highest holocene raised shoreline in scotland is now believed to be overlapped around the periphery of the uplifted area by the later blairdrummond shoreline isobase models based upon quadratic trend surface analysis of available comparable height dat

long term shoreline changes and the concentration of heavy minerals in beach sands of the nile delta egypt abstract analyses have been undertaken of shoreline positions established from beach profile surveys at 65 positions along the coastline of the nile delta spanning the years 1971 to 1990 the analyses identify long term linear trends as well as any cycles in the horizontal movement of shoreline positions the results reveal longshore patterns wherein erosion along a stretch of coast gives way to accretion in an adjacent stretch defining a subcell within the overall littoral system of the delta the rate of shoreline retreat has been greatest along the rosetta promontory 106 m yr and damietta promontory 10 4 m yr significant erosion has also occurred along the central bulge of the delta coast but at a lesser rate 6 5 m yr areas of accretion exist within the saddles or embayments between the promontories with the maximum shoreline advance averaging about 13 m yr the identified patterns of erosion versus accretion along the delta reflect the natural processes of wave induced longshore currents and sediment transport associated with this longshore sediment movement is a selective transport of different minerals according to their densities and grain sizes with the light minerals quartz and feldspar having the highest advection rates and the dense opaque minerals the lowest rates tending to remain behind as a lag within the erosion areas as a result of this longshore grain sorting paralleling the patterns of shoreline erosion versus accretion there are correlations between the rates of shoreline change and the heavy mineral contents and mean grain sizes of the beach sediments these large scale delta wide patterns are affected somewhat by local shoreline changes and mineral variations induced by the construction of jetties or shoreline protection structures

tidal wetland record of holocene sea level movements and climate history abstract paleontological geochemical and lithological indicators of former marine and nonmarine influence are correlated between 13 cores from a tidal wetland wolfe glade on the southeast coast of delaware bay twenty new radiocarbon dates are used to establish the chronostratigraphy of marsh facies sediment iron content weight loss on ignition and remains of plants diatoms and foraminifera known to tolerate specific tidal inundation cycles are used to describe cored facies originating from supratidal intertidal and subtidal salt marsh subenvironments pollen assemblages are used to infer local holocene climate fluctuations and to reconstruct paleoenvironments during marsh evolution the record of paleoclimatology suggests the atlantic chron was warm with variable humidity in the region whereas the subboreal was dominated by cool and humid conditions the subatlantic was warmer and initially dryer with a cool humid phase prior to about 1 ka returning to warmer humid conditions in the last several centuries local relative sea level movements are characterized by five rapid short term episodes when the rate of sea level rise accelerated relative to the rate of marsh aggradation these episodes are recorded by transgressive facies contacts at 5 3 0 2 ka 4 4 0 2 ka 3 25 0 2 ka and 1 8 0 2 ka sidereal years an earlier transgressive facies contact dated 6 9 0 2 ka is probably not the product of a true sea level movement sea level movements are recorded throughout the marsh as palustrine or high marsh peats or peaty overlain by lower intertidal or subtidal marine deposits several features suggest that these episodes are local relative transgressions produced by short term accelerations in the rate of sea level rise relative to marsh aggradation the contemporaneity and apparent suddenness of marine inundations the sequence of facies indicating marine drowning the presence of similar events in marshes elsewhere in delaware bay and the marsh wide extent of indicative facies transitions we propose that the rapid and frequent sea level movements observed in wolfe glade are the result of surges and relaxations in the gulf stream and associated spin up and partial collapse of the north atlantic gyre in response to winds generated by changes in the north atlantic atmospheric thermal gradient associated with holocene climate fluctuations

the pyroclastic tonsteins of the sabero coalfield north western spain and their relationship to the stratigraphy and structural geology abstract the sabero coalfield comprises a succession of strata of over 2000 m of late barruelian to early stephanian b sensu carmaux age proposals have earlier been made to base the boundary stratotype for the top of the barruelian on a section in the lower half of the sabero succession ten different tonstein bands have been located in the principal coal bearing lithostratigraphic units raposa formation sucesiva formation herrera beds and the unica beds material from over 50 sample locations from both surface outcrops and from underground coal workings has been studied by means of microscope thin sections supported by x ray diffraction spectrometry xrd analysis and whole rock chemical analysis on a small number of selected samples all of the 10 bands occur as kaolinite coal tonstein in which the main constituent is kaolinite both as matrix and as abundant fragmentary crystals and phenocrysts the latter predominantly comprising pseudomorphs after biotite and feldspar graupen and irregular kaolinite masses occur in some cases conserving relict structures of volcanic glass feldspars have been identified in the range anorthite albite potassic feldspars are in general absent quartz occurs as acicular splinters and as form and paraform with magmatic re absorption embayments and glass inclusions tridymite has been identified in two bands other accessory primary constituents include idiomorphic apatite and zircon the composition and petrographical features are entirely consistent with a pyroclastic origin locally some apparently secondary alteration of kaolinite to illite is observed and one band shows a lateral progression from kaolinite tonstein through kaolinite illite tonstein to illite tonstein which is apparently coincident with increased intensity of tectonisation a number of the bands have served as the means of resolving structural and stratigraphic problems in the sabero coalfield in particular the identification of level 31 has permitted the reinterpretation of paquete central one of the traditionally principal areas of coal working previously considered to comprise some five or six seams and now recognised as a series of three or more structural repetitions of two workable seams only the overall thickness interpreted for the herrera beds is correspondingly reduced the relatively common presence of ca plagioclase phenocrysts in some bands suggests a rather more dacitic magmatic origin than for the otherwise closely comparable tonsteins of the massif central of france the sabero tonstein bands are closely similar in character and composition with those known in the cinera matallana coalfield and a similar area of origin is surmised although further stratigraphical and petrological work is required before firm correlations can be achieved

late holocene higher sea level indicators from eastern australia abstract new age data from intertidal organisms exposed on coastal cliffs in northern new south wales suggest that in that area sea level was slightly more than 1 m higher about 3420 yrs b p and may have fallen to its present level since 1780 yrs b p these findings if regionally significant are important because they indicate that the tidally constructed zonations of organisms on high energy rocky coast could provide a more precise record of sea level behaviour than the study of constructional geomorphic features often related to storm events such as beach ridges chenier plains tidal deltas etc or mangrove peats

瀬戸内海中部 出崎海岸 岡山県玉野市 における埋没泥炭層の再検討 特に完新世中期の相対的海水準変動との関係について

patterns of beach sand sorting and shoreline erosion on the nile delta abstract rapid erosion has occurred on the beaches of the nile delta in response to dam construction that has cut off the river sediment supply this erosion is greatest adjacent to the two distributary mouths with shoreline retreat rates up to 60 m per year the eroded sand is carried alongshore away from the river mouths and deposited in areas of shoreline accretion these patterns of shoreline erosion and deposition are reflected in the mineralogy of the beach sands on a delta wide scale high density opaques garnet and zircon are concentrated in the erosion areas to form black sand placers lower density hornblende as well as quartz and feldspars are preferentially transported out of the erosion areas and deposited in the stretches of accreting shoreline a detailed analysis of these sorting patterns has been undertaken with beach samples from abu quir bay at the western end of the delta concentrations of opaques zircon rutile and garnet decrease exponentially with longshore distance from the river mouth while augite and hornblende increase exponentially the coefficients in the exponential equations are found to be a function of mineral density demonstrating the importance of this grain property in mineral sorting leading to the observed compositional variations along the shores of the nile delta

sedimentary evolution of the north norfolk barrier coastline in the context of holocene sea level change holocene sediments of the north norfolk coast nnc between weybourne and hunstanton have been studied using geophysical sedimentological biofacial and dating techniques new cores and refraction seismic data have defined the topography of the pre holocene surface and show that the nnc sediment prism is underlain by an east west trending quaternary trough probably a palaeo river valley the age of the holocene fill has been dated using radiocarbon and luminescence dates while sedimentation rates were constrained by and compared with modern rates using radionuclide data the holocene sediments are divided into a sandy barrier lithofacies association lfa and a muddy silty peat back barrier lfa the oldest holocene sediments are peats formed on an undulating till surface these peats were forming by 11 10 cal ka bp and continued to form until at least 7 cal ka bp in a number of places as holocene sea level rose marine mudflat and saltmarsh environments began to form between 7 and 6 cal ka bp east of holkham and around 6 cal ka bp or younger west of holkham a marked erosion surface between the barrier and back barrier lfa in the holkham to burnham overy area is imperfectly dated at 3 cal ka bp but suggests the sediment prism has thinned by about 3 km over 6 to c 3cal ka bp this surface probably records the westward progress of laterally migrating tidal channels that caused back barrier sediment erosion along with shoreface processes as sea level rose small scale regressive and transgressive saltmarsh sequences occur at different elevations along strike but cannot be correlated suggesting that the control on saltmarsh and mudflat development is autocyclic rather than allocyclic generally transgressive and regressive events are related to disposition of coastal barriers and these are superimposed on a general facies evolution governed by regional sea level change predictions about how this barrier coastline might respond to increased rates of regional sea level change caused by global warming or climatic events like increased storminess require an understanding of how specific segments of the coastline have responded over millennial time scales this longer term evolution provides the baseline information for decision making and management strategy it is likely that sandy sediment supply is limited on the nnc and this implies that the barriers will continue to move landward probably at increased rates relative to today suggesting that parts of the nnc will become more vulnerable to erosion and flooding

late holocene coastal plain stratigraphy and sea level history at hanalei kauai hawaiian islands abstract fluvial marine and mixed fluvial marine deposition on the coastal plain of hanalei bay on the north shore of kauai hawaii records a middle to late holocene fall of relative sea level radiocarbon dating of the regression boundary preserved in the stratigraphy of the coastal plain documents a seaward shift of the shoreline beginning at least 4800 4580 cal yr b p and continuing until at least 2160 1940 cal yr b p marine sands stranded in the backshore and coastal plain environment are buried by fluvial floodplain and channel sands silts and muds in places erosion at the regression contact exposed older marine sands thus increasing the hiatus at the regression disconformity the shoreline regression is best explained as the result of a fall in relative sea level the age and elevation of the cored regression boundary at sites that have not been influenced by erosion are consistent with a middle to late holocene highstand of relative sea level as predicted by geophysical models of whole earth deformation related to deglaciation

evaluation of holocene crustal movement in the ako plain western japan holocene sea level observations have been obtained from the ako plain in western japan in this coastal area the holocene crustal movements have been evaluated except the crustal response due to the last deglaciation by comparing observations and theoretical predictions of relative sea level rsl variations analyses of diatom assemblages and sedimentary sulphur in core sediments were used along with radiocarbon dates to derive the rsl variations a crustal movement rate between 0 2 mm and 0 2 mm per year corrected for the prediction fits well with the observed rsl index points owing to the constraint of the reconstructed palaeo mean sea level pmsl at 7300 cal bp the coast of the ako plain may have the best estimate of a tectonic subsidence rate of 0 0 2 mm yr the tectonic uplift rates along the tectonically active coast of western kobe were derived to be 0 3 0 7 mm yr and 0 11 0 45 mm yr for tarumi and tamatsu respectively relative to ako over the period concerned the relative uplift along the traverse from ako to western kobe is primarily the result of the crustal movement resulting from the active faulting of the rokko awaji fault system rfs

influence of shoreline erosion and accretion on texture and heavy mineral compositions of beach sands of the burullus coast north central nile delta egypt shoreline changes result from shoreline orientation and jetty construction are investigated at the central sector of the nile delta on the basis of systematic beach profile surveys spanning the years 1971 to 1992 maximum accretion 4 9 m yr occurs along the western barrier due to construction of the west jetty on the burullus lagoon inlet whereas greatest erosion 5 5 m yr about 3 km east of the burullus inlet dominated along the unprotected sector of the eastern barrier beach sand composition is in part relict reflecting an alongshore mineral sorting of sediments of former sebennitic branch two heavy mineral groups factors were obtained by applying q mode factor analysis on the heavy mineral data of the beach sand one factor group is dominated by augite hornblende and epidote whereas the second consists of opaques garnet zircon rutile and monazite these two factors are influenced by both the selective sorting of heavy minerals and point sources of relict sediment factor 1 is associated with the accreted coarse grained sand west of the jetty derived from the rosetta branch farther west whereas factor 2 tends to concentrate in fine grained sands at eroded beach related in part to the former sebennitic beach the identified pattern of deposition on the updrift side near the west jetty and erosion near and at greater distance from the east is reflected in sand size and mineral composition of beach sand these patterns reflect the natural processes of wave induced longshore current and sediment transport there are correlation between the rates of shoreline change and the heavy mineral groups and mean grain sizes of the beach sediments

morphological drainage and eolian controls on the microtidal patara beach sediments eastern mediterranean textural geochemical and mineralogical investigations abstract the effects of dominant hydrodynamic morphological fluvial and hinterland geological source conditions on the texture and composition of the microtidal and dissipative patara beach mediterranean coast of sw turkey sediments were investigated at 47 locations patara beach sediments are composed entirely of sand fine sand 5 94 was more abundant in the northwestern section while medium sand contents 2 94 increased in the central and southeastern sections moderately to well sorted mostly 0 3 0 7 o sediments tend to show overall better sorting towards the southeast in the net longshore current direction terrigenous carbonate grains derived from the hinterland constituted 6 50 as caco3 with varying tendencies to increase or decrease within sections alongshore total heavy mineral concentrations in bulk sediments 1 17 mostly

mid and late holocene sea level changes in roudsea marsh northwest england a diatom biostratigraphical investigation diatoms vascular vegetation sediment data and water salinity from contemporary intertidal environ ments in roudsea marsh northwest england are used to define altitudinal relationships between diatom assem blages and reference water levels comparison of these data with the high resolution diatom biostratigraphy of a fossil marsh sequence allows identification of fluctuations of relative sea level in the mid and late holo cene two oscillations in relative sea level are recorded a rise in sea level 0 6 m led to the inundation of the site after 6000 bp and was followed by a fall in sea level c 1 m around 4700 bp a second rise in sea level 0 5 m occurred before 2420 bp and was followed by a relatively stable or smaller rise of sea level during the last millennium the use of diatom groups based on marsh altitude was successful

evolution of a tide dominated abandoned channel a case of the abandoned qingshuigou course yellow river abstract deltaic river systems including both active channels and abandoned channels are of significant importance to understand the deltaic morphology as well as to the coastal management and ecosystem maintenance however the healing process of the abandoned channel has not yet been well understood based on the sedimentary record and hydrographic surveys the deposit architecture and sediment dynamics of a tide dominated abandoned channel the abandoned qingshuigou channel of the yellow river are investigated the abandoned qingshuigou channel has been fully disconnected from the main river channel since an artificial diversion completed in 1996 twenty years after the abandonment sedimentation with an average thickness of 20 cm was identified in the abandoned channel illustrating a prominent seaward thickening trend from middle to lower channel at the present river mouth of the abandoned channel sedimentation layer with a thickness of 38 cm well matched the sedimentation rates derived from both chronological framework 1 85 cm yr derived from 210pb and sedimentary facies 1 90 cm yr these deposits are composed by fine grained sediment and enriched with organic matters differing largely from the river dominated deposits before abandonment tidal delivery of the sediment resuspended in the shallow water nearby qingshuigou river mouth dominated the refilling process of the abandoned channel meanwhile severe erosion near the abandoned river mouth shortened the channel 23 5 km in 1996 versus 14 5 km in 2018 and induced a lateral migration of the tidal inlet due to seasonally varying hydrodynamics the tide dominated abandoned qingshuigou channel converts from a sediment sink in summer seasons to both a source and a sink in winter seasons

diatom and stable isotope records of late holocene lake ontogeny at indrepollen lofoten nw norway a response to glacio isostasy and neoglacial cooling borg indrepollen is a coastal lake on the island of vestvagoy lofoten nw norway a sedimentary sequence spanning the last 4500 cal yr bp was analysed for diatom c n and stable isotopes 13c and 15 n the record provides clear evidence of glacio isostatic rebound in the lofoten region five distinct lithostratigraphic geochemical zones i v and four major diatom zones a d were identified the early record i iii a biii 4500 550 cal yr bp contains coarse sedimentary material and diatoms indicative of more marine conditions the correlation between the isotopic data high 13c and low c n and trends in the biological data marine brackish flora suggest the marine influence on the indrepollen basin is a controlling factor of the source of organic material the latter part of the record iv c 550 cal yr 550 226 indicates a transitional phase from marine dominated diatom to brackish taxa and is coincident with a section of microlaminations in the core the youngest zone v d 226 cal yr bp

holocene sedimentation on the north norfolk barrier coast in relation to relative sea level change fourteen distinct sedimentary environments have been recognised in the surface sediments of the intertidal zone of the north norfolk coast nine of these can be distinguished in borehole samples on the basis of sedimentological and micro palaeontological characteristics they comprise gravel channel sand intertidal sand intertidal silty sand intertidal mud and marsh creek lower salt marsh upper salt marsh dune sand and peat sediment accumulations have been penetrated to a depth of 8 m od and basal peats dated by 14c back to 8410 50 years bp an overall rate of sediment accumulation and subsidence of about 1 m per thousand years is indicated there is considerable persistence of sedimentary environments in the same areas during up building but some erosion and roll over of the coastal barrier system has occurred evidence of positive and negative sea level tendencies are present in the record but the main development of the tract is determined by sediment supply to the beach and marshes positive sea level tendencies occur at c 6610 5970 4630 and 2790 bp negative sea level tendencies occur at 4520 to 4450 and possibly 3470 bp

holocene uplift derived from relative sea level records along the coast of western kobe japan abstract mid to late holocene sea level observations have been obtained from tamatsu and tarumi in western kobe japan in this tectonically active area we evaluate the local tectonic effect during the holocene by comparison between observations and predictions of sea level variations for the purpose of this study we analysed the diatom assemblages and carried out sulphur analysis of sediments these were used along with radiocarbon dates to derive relative sea level variations for the sites a rate of tectonic uplift of between 0 1 and 0 3 mm per year corrected for the prediction fits well with relative sea level rsl index points of tamatsu at 6415 5320 cal bp depending on the altitude of the rsl index point at about 5700 cal bp the best estimate of the rate of tectonic uplift for tamatsu is calculated as 0 11 0 25 mm yr over the period concerned a rate of tectonic uplift between 0 3 and 0 5 mm per year is derived for tarumi at about 7300 and 3835 3365 cal bp these values may explain the height distributions of the late pleistocene marine terraces along the coast of the western kobe providing a first approximation for rates of local crustal movements during the late quarternary

selective entrainment of sediment graded by size and density under waves the influence of near bed sorting processes on heavy mineral content in suspension is discussed sediment concentrations above a rippled bed of mixed quartz and heavy mineral sand were measured under regular nonbreaking waves in the laboratory using the traditional gradient diffusion process settling velocity would be expected to strongly affect sediment distribution this was not observed during present trials in fact the vertical gradients of time averaged suspension concentrations were found to be similar for the light and heavy minerals despite their different settling velocities this behavior implies a convective rather than diffusive distribution mechanism between the nonmoving bed and the lowest suspension sampling point light and heavy mineral concentration differs by two orders of magnitude this discrimination against the heavy minerals in the pickup process is due largely to selective entrainment at the ripple face bedform dynamics and the nature of quartz suspension profiles are found to be little affected by the trialed proportion of overall heavy minerals in the bed 3 8 22 1

planform and mobility in the meaipe maimba embayed beach on the south east coast of brazil the meaipe maimba embayed beach mmeb on the south east coast of brazil has been subject to anthropogenic pressures since the 70 s in this study we discuss the adequacy and contribution of the parabolic planform model to determine the planform and variability of the mmeb taking into consideration variation in wave conditions the role of different controlling conditions on the planform variability is analyzed as well as the morphological and planform mobility mmeb exhibited a new configuration in response to the construction of a harbor which interrupted the longshore sediment transport after four decades three particular morphodynamic sectors have been recognized along the beach the central sector is more exposed to normal wave incidence and cross shore processes predominate the northern and southern sectors are influenced by wave diffraction processes around the headlands and port respectively in the northern sector the presence of secondary headlands and inner islands imposed a geomorphological control on beach morphology and coastal processes the use of the parabolic planform model provided useful insights for the assessment of potential planform mobility since the decadal shoreline evolution combined with beach profiles and sediment characteristics allowed understanding of the beach mobility processes and supported the interpretation of modeling results

longshore size grading on a boulder beach abstract longshore size sorting on boulder beaches has not previously been reported in a boulder beach comprising beachrock slabs we report systematic longshore clast size grading the boulder beach at mission rocks south africa is deposited on an elevated 3 m msl shore platform and comprises imbricated clasts up to 5 m in the a axis dimension 9 tonnes the clasts are derived from adjacent intertidal beachrock and eolianite outcrops and are emplaced during high magnitude wave events four distinct downdrift fining cells are present each is 40 50 m long the sorting is attributed to post emplacement clast redistribution in which the smallest clasts are transported most frequently by lower magnitude storms and therefore travel farthest downdrift the updrift cell boundary is marked by boulders 5 m in length that exceed the transport threshold for all but the most energetic of storms while the downdrift limit contains clasts 0 3 m in length this mechanism of longshore size sorting does not rely on variations in longshore wave power as does cell development on sand and gravel beaches the alongshore sorting via multiple high and variable magnitude events over a period of time distinguishes these coarse clast deposits from those of single extreme events whether storms or tsunamis

identifying coseismic subsidence in tidal wetland stratigraphic sequences at the cascadia subduction zone of western north america tidal wetland stratigraphy reveals that great plate boundary earthquakes have caused hundreds of kilometers of coast to subside at the cascadia subduction zone however determining earthquake recurrence intervals and mapping the coastal extent of past great earthquake ruptures in this region are complicated by the effects of many sedimentologic hydrographic and oceanographic processes that occur on the coasts of tectonically passive as well as active continental margins tidal wetland stratigraphy at many cascadia estuaries differs little from that at similar sites on passive margin coasts where stratigraphic sequences form through nonseismic processes unrelated to coseismic land level changes methods developed through study of similar stratigraphic sequences in europe provide a framework for investigating the cascadia estuarine record five kinds of criteria must be evaluated when inferring regional coastal subsidence due to great plate boundary earthquakes the suddenness and amount of submergence the lateral extent of submerged tidal wetland soils the coincidence of submergence with tsunami deposits and the degree of synchroneity of submergence events at widely spaced sites evaluation of such criteria at the cascadia subduction zone indicates regional coastal subsidence during at least two great earthquakes evidence for a coseismic origin remains equivocal however for the many peat mud contacts in cascadia stratigraphic sequences that lack 1 contrasts in lithology or fossils indicative of more than half a meter of submergence 2 well studied tsunami deposits or 3 precise ages needed for regional correlation paleoecologic studies of fossil assemblages are particularly important in estimating the size of sudden sea level changes recorded by abrupt peat mud contacts and in helping to distinguish erosional and gradually formed contacts from coseismic contacts reconstruction of a history of great earthquakes for the cascadia subduction zone will require rigorous application of the above criteria and many detailed investigations

late quaternary sea level changes and crustal movements in eastern england and eastern scotland an assessment of models of coastal evolution abstract the most comprehensive records of late quaternary coastal environmental change in eastern england and eastern scotland are obtained from the intercalated semi terrestrial peats and intertidal silts clays and sands that have accumulated in estuaries and coastal lowlands radiocarbon dated sea level index points from sites in north east england are evaluated with reference to first a conceptual model of coastal sedimentary environments and second a model of pollen assemblages in holocene coastal environments analysis of these new data indicates differential crustal uplift within north east england of ca 0 2 mm yr for the last 4000 to 5000 radiocarbon years this pattern of uplift is consistent with models of holocene crustal deformation in scotland and england the uplift is attributable to the combined effects of ice unloading and water loading

relative sea level changes and crustal movements in britain and ireland since the last glacial maximum abstract the new sea level database for britain and ireland contains 2100 data points from 86 regions and records relative sea level rsl changes over the last 20 ka and across elevations ranging from 40 to 55 m it reveals radically different patterns of rsl as we move from regions near the centre of the celtic ice sheet at the last glacial maximum to regions near and beyond the ice limits validated sea level index points and limiting data show good agreement with the broad patterns of rsl change predicted by current glacial isostatic adjustment gia models the index points show no consistent pattern of synchronous coastal advance and retreat across different regions 100 500 km scale indicating that within estuary processes rather than decimetre and centennial scale oscillations in sea level produce major controls on the temporal pattern of horizontal shifts in coastal sedimentary environments comparisons between the database and gia model predictions for multiple regions provide potentially powerful constraints on various characteristics of global gia models including the magnitude of mwp1a the final deglaciation of the laurentide ice sheet and the continued melting of antarctica after 7 ka bp

sediment yield determination using uranium series radionuclides the case of the wash and fenland drainage basin eastern england abstract water and sediment samples were collected from the fenland drainage basin to assess the fluvial contribution to the sediment budget of the wash on the east coast of england using the uranium series disequilibrium found in the products of the weathering system river sediment and water the ratio of material carried in solid form to that dissolved u s u w was assessed and the total flux of weathered material sediment yield was quantified the results show that the u s u w ratio is controlled to a degree by catchment geology and hydrology and that there is a marginal seasonal increase from between 3 28 3 95 and 4 60 0 44 summer mean and weighted mean to between 5 35 3 05 and 6 07 0 63 winter mean and weighted mean the best estimate of annual sediment flux from the fenland to the wash is between 2800 and 17 700 tonnes yr 1 equivalent to a rate of 0 22 1 42 tonnes km 2 yr 1 this is lower than previous estimates for the region but reinforces the argument that sediment reworking within the wash and erosion of the adjacent coasts and sea beds are important sources of sediment for the intertidal flats and salt marshes

changing pattern of accretion erosion of the modern yellow river huanghe subaerial delta china based on remote sensing images abstract the yellow river shifted from the diaokou course to the qingshuigou course in 1976 and shifted again at the north bank of the qingshuigou course in 1996 as a result the entire modern yellow river delta has experienced complicated patterns of erosion and accretion multitemporal remote sensing data of landsat mss and tm from 1976 to 2000 totaling twenty scenes were used to examine the changing pattern of accretion and erosion of the modern yellow river subaerial delta with gis tools during the period 1976 to 2000 the maximum erosion occurred at the head of the last two abandoned promontories diaokou and shenxiangou promontories where the coastline retreated landward over 7 and 4 5 km respectively with mean net erosion rates of 0 29 and 0 19 km a respectively in contrast the maximum accretion occurred at the head of the qingshuigou promontory where the coastline advanced seaward over 20 km with a mean net accretion rate of 0 83 km a the coastline at the head of the q 8 promontory also advanced seaward 7 km with a mean net accretion rate of 0 29 km a during the period 1996 to 2000 total area of the diaokou and shenxiangou promontories was reduced by 141 3 km 2 with a mean net erosion rate of 6 03 km 2 a total area of the qingshuigou and q 8 promontories increased by 384 16 and 11 88 km 2 respectively with mean net accretion rates of 16 4 and 3 03 km 2 a respectively relative to the diaokou shenxiangou and qingshuigou promontories the west area of the diaokou promontory and south area of the qingshuigou promontory were relatively stable although minor erosion occurred the general pattern of accretion and erosion of the modern yellow river subaerial delta was divided into three stages rapid accretion stage 1976 1984 accretion erosion adjustment stage 1985 1995 and slow erosion stage 1996 present the factors affecting the pattern of erosion and accretion over the yellow river delta such as structural geology the yellow river sediment discharge coastal processes meteorological conditions human activity sea level rise and land subsidence were summarized the cumulative area of increase over the entire subaerial delta is closely correlated with the cumulative yellow river sediment discharge wave induced longshore current is the major driving force to transport sediment from eroded areas along the last two abandoned promontories diaokou and shenxiangou promontories mostly westerly and partially easterly together with these coastal processes is the geographical shift of the yellow river course associated with its discharge regime after 1976 leading to the accretion along the present qingshuigou promontory and then the q 8 promontory

magnetic mineral and sediment porosity distribution on a storm dominated shelf investigated by benthic electromagnetic profiling bay of plenty new zealand abstract magnetic susceptibility and electric conductivity within the uppermost meter of the seafloor were measured with high resolution along 33 coast normal profiles in the bay of plenty new zealand using the recently developed electromagnetic benthic profiler marum neridis iii these parameters are used to determine magnetic mineral concentration and porosity of mostly volcanoclastic sediments between 2 and 35 m water depth to investigate distribution and formation of magnetic mineral enrichments on a storm dominated shelf in general magnetic mineral concentration susceptibility is inversely correlated to porosity conductivity along profiles susceptibility maxima and conductivity minima were commonly found on bathymetrical elevations such as dune and ripple crests cores and grab samples show the highest degree of enrichment in the uppermost 20 cm of the seafloor complementing petromagnetic analysis indicates a spectrum of feti oxides in the sediment ranging from magnetite and hematite over titanomagnetite tm40 and tm60 to titanohematite likely th80 and th95 three distinct zones of magnetic mineral enrichment could be identified a coast parallel structure with low porosity in recent fine sand between 5 and 20 m water depth a widespread structure with low porosity in older transgressionally reworked coarse sand in up to 30 m water depth and third structure coarse sand with high porosity located mostly below 30 m while the fine sand structure is interpreted as the result of an active process the other two appear to be relics sorting by grain size selective entrainment appears to be the major formation mechanism this study demonstrates how electromagnetic benthic profiling in combination with environmental magnetic laboratory analysis provides reliable highly interpretable data that allow insight into sorting processes within the boundaries of established lithofacies that are difficult to detect using a classical sedimentological approach

developing detailed records of relative sea level change using a foraminiferal transfer function an example from north norfolk uk this paper provides a brief overview of the transfer function approach to sea level reconstruction using the example of two overlapping sediment cores from the north norfolk coast uk the advantages and limitations of the transfer function methodology are examined while the selected cores are taken from different sites and display contrasting patterns of sedimentation the foraminiferal transfer function distils comparable records of relative sea level change from both sequences these reconstructions are consistent with existing sea level index points from the region but produce a more detailed record of relative sea level change transfer functions can extract sea level information from a wider range of sedimentary sub environments this increases the amount of data that can be collected from coastal deposits and improves record resolution the replicability of the transfer function methodology coupled with the sequential nature of the data it produces assists in the compilation and analysis of sea level records from different sites this technique has the potential to bridge the gap between short term instrumental and long term geological or geophysical records of sea level change

coastal and sea level changes during the holocene in bangladesh abstract the aim of the study is to reconstruct the holocene sea level history along a section of the coast of bangladesh detailed litho bio and chronostratigraphic techniques have been applied to unveil the nature of sedimentary sequences in association with the events of the holocene marine transgressions and regressions samples were collected from panigati near khulna the study provides evidence of five periods of marine transgression each followed by a regression during the holocene each minerogenic sediment layer indicates a marine episode and the sediments were deposited under intertidal to estuarine conditions each peat layer is in situ and indicates a regression of the sea it is difficult to separate the regional eustatic components contributing to these relative sea level movements although processes operating locally and regionally are clearly evident a sea level curve together with possible error ranges has been proposed for this part of bangladesh since the early to mid holocene an average relative sea level rise of 1 07 mm yr has been estimated

gradation effects in sediment transport to determine the effects of grain size and density gradation in oscillatory sheet flow experiments are conducted in an oscillating water tunnel a formal derivation of a schematised transport model shows that the transport rates per sediment fraction can be determined with and without the assumption of an active layer a technique that measures sediment composition from natural occurring radionuclides is used to determine the transport rates without that assumption of an active layer the measurements on total sediment transport rates and suspended sediment concentrations show that effects of gradation are present the effects of size gradation are mainly in the increased transport rates of the coarse fraction with respect to the uniform coarse material and the availability at the bed under similar conditions the experiments on density graded sediments indicate that total mass transport rates are larger than the mass transport rates of quartz material whilst the transport rates of the quartz fraction show that this fraction is not hindered by the availability at the bed

on the postglacial isostatic adjustment of the british isles and the shallow viscoelastic structure of the earth summary observations of postglacial relative sea level rsl history at sites beyond the margins of the main accumulations of wu rm wisconsin devensian ice may be invoked to test the accuracy of global models of the glacial isostatic adjustment process the existing database of rsl time series for the british isles forms a continuous network of sites that sample the coasts of scotland england and wales fairly uniformly and which may be especially important in this regard not only are these 14c data for the holocene epoch of very high quality in terms of our knowledge of the coastal environment and relationship to palaeo sea level of each age measurement but they are especially numerous and relate to an island that was itself partly glaciated in the north essentially ice free in the south and located well outboard of the massive ice sheet that covered fennoscandia at the last glacial maximum lgm taken together the time series from 55 distinct locations allow us to perform a fairly stringent test of the recently formulated ice 4g vm2 global model of the isostatic adjustment process even without modification this model has been shown to fit most of the time series in the uk data set rather well in order to satisfy very recently published a priori constraints on the maximum thickness of the scottish ice sheet however we find that the lithospheric thickness the feature of the radial viscoelastic structure to which the rebound data from scotland are most sensitive must be somewhat reduced whereas the assumed thickness of the lithosphere in ice 4g vm2 was near to 120 km best fits to the scottish data require a lithospheric thickness near to 90 km this reduced value for lithospheric thickness agrees exceedingly well with the latest estimates of this earth property based on the inversion of oceanic geoid and topography data as the asymptotic thickness characteristic of the oldest ocean floor this would appear to be the best possible a priori estimate for the thickness of the cratonic lithospheres upon which the largest ice sheets of the late pleistocene are known to have rested we also demonstrate explicitly that inferences of the shallow viscoelastic structure beneath the british isles are strongly influenced by the details of the history of deglaciation at remote locations at antarctica in particular

analysis and interpretation of holocene sea level data the geography of the geoid1 and the lack of an acceptable methodology and definition of terms for sea level studies have impeded the realization of the objectives of the international geological correlation programme project 61 on holocene sea level changes2 these were to establish a graph of the trend of mean sea level over the globe and the relationship between sea level climate change and the global ice budget2 a solution to the problems of correlation is proposed here the use of terms transgression and regression has been a major cause of misinterpretation2 and the terms transgressive overlap and regressive overlap have been proposed as descriptive lithostratigraphic terms in which no process is implied3 5 the processes involved in the development of coastal stratigraphical sequences are dependent on the position and rate of change of sea level and these sequences contain evidence of tendencies of sea level6 8 the application of the concept of sea level tendency permits meaningful correlations between rising and subsiding areas and introduces an objectivity to correlation schemes showing transgression sequences 9 10

downstream lightening and upward heavying experiments with sediments differing in density sorting and selective transport of particles by material density is important for understanding a wide range of processes including the formation of mineral placers deposition of mine tailings and routing of tracers and contaminants this article describes an experimental study of the transport of mixtures of particles of differing density in a sediment feed flume during the runs a downstream prograding wedge shaped deposit was formed results show two sorting processes i longitudinal sorting characterized by preferential deposition of heavy particles in the upstream part of the deposit downstream lightening and ii vertical sorting with less dense particles preferentially deposited in the lowermost portion of the migrating front upward heavying downstream lightening is the analogue of the well known downstream fining observed in the more studied case of mixtures of heterogeneous size with the same density in both cases the lighter particles are carried further downstream than the heavier particles upward heavying is unexpected when compared with deposits of heterogeneous size and same density particles where the heaviest i e coarsest particles are deposited in the lowermost part of the front the physical mechanism underlying this upward heavying might be related to the physics of gravity driven granular flows the front of the deposit acts like a dense granular flow down an inclined plane in this case the denser particles settle away from the free surface and at the top of the heap while the lighter particles flow to the bottom as the front of the deposit advances this progressively gives rise to an upward heavying pattern the application of classical surface based fractional bedload transport models suggests that equal mobility is not approached in the case of mixtures of particles with uniform size and different densities this study hypothesizes that other mechanics related to the physics of the segregation processes in these systems contribute to these results

holocene relative sea level movements along the north norfolk coast uk abstract relative changes in holocene sea level are reconstructed from foraminiferal assemblages in seven cores recovered from the intertidal zone of north norfolk eastern england a total of 33 radiocarbon and infra red stimulated luminescence dates provide a detailed chronological framework for these changes a transfer function approach developed from modern uk foraminiferal datasets establishes a series of 21 new sea level index points for this coastline which are combined with 18 existing index points and a further number of limiting values errors associated with changing tidal ranges through the holocene are reduced by adopting recently developed tidal models for this period this new approach allows the use of foraminiferal assemblages to be extended from the upper saltmarsh environment traditionally used for sea level studies to lower elevations in the tidal frame and include clastic detrital sediments the results confirm the previously observed trend of continuously rising sea levels in this area during the last 10 000 years which is consistent with a glacial isostatic adjustment model relative sea level rsl rises from an observed minimum of approximately 13 50 m od at about 7500 cal bp to approximately 4 0 m at about 5300 cal bp which equates to a mean rise of c 4 3 mm yr 1 subsequently rsl rose gradually to present levels although there is evidence that a minor reverse in this trend occurred between 4000 and 2000 cal bp when sea level fell by about 1 m to c 3 5 m the rate of land subsidence for north norfolk is 0 54 0 03 mm yr 1 inverse of late holocene sea level rise

dramatic beach and nearshore morphological changes due to extreme flooding at a wave dominated river mouth abstract record flooding on the santa clara river of california usa during january 2005 injected 5 million m3 of littoral grade sediment into the santa barbara littoral cell approximately an order of magnitude more than both the average annual river loads and the average annual alongshore littoral transport in this portion of the cell this event appears to be the largest sediment transport event on record for a southern california river over 170 m of local shoreline mean high water mhw progradation was observed as a result of the flood followed by 3 years of rapid local shoreline recession during this post flood stage linear regression determined shoreline change rates are up to 45 m a 1 on the subaerial beach mhw and 114 m a 1 on the submarine delta 6 m isobath starting approximately 1 km downdrift of the river mouth shoreline progradation persisted throughout the 3 year post flood monitoring period with rates up to 19 m a 1 post flood bathymetric surveys show nearshore 0 to 12 m depth erosion on the delta exceeding 400 m3 m a 1 more than an order of magnitude higher than mean seasonal cross shore sediment transport rates in the region changes were not constant with depth however sediment accumulation and subsequent erosion on the delta were greatest at 5 to 8 m and accretion in downdrift areas was greatest above 2 m thus this research shows that the topographic bulge or wave of sediment exhibited both advective and diffusive changes with time although there were significant variations in the rates of change with depth the advection and diffusion of the shoreline position was adequately reproduced with a simple one line model although these modeling techniques miss the important cross shore variations observed in this area this study illustrates the importance of understanding low frequency high volume coastal discharge events for understanding short and long term sediment supply littoral transport and beach and nearshore evolution in coastal systems adjacent to river mouths

shipboard magnetic field noise reveals shallow heavy mineral sediment concentrations in chesapeake bay abstract shipboard magnetic field data collected over chesapeake bay exhibit low amplitude short wavelength anomalies that most likely indicate shallow concentrations of heavy mineral sediments piston core layers and black sand beach samples exhibit enhanced magnetic susceptibilities and carry remanent magnetization with mineralogical analyses indicating ilmenite and trace magnetite and or maghemite and hematite the anomalies are subtle and would be filtered as noise using traditional approaches but can instead be highlighted using spectral methods thus providing nearly continuous coverage along survey tracks the distribution of the anomalies provides constraints on relevant sorting mechanisms comparisons to sonar data and previous grab samples show that two of three areas surveyed exhibit short wavelength anomalies that are clustered over sand covered areas suggesting initial sorting through settling mechanisms this is supported by a correlation between core magnetic susceptibility and grain size near the choptank river where sediment resuspension is wave dominated anomalies show a sharp decrease with seafloor depth that cannot be explained by signal attenuation alone in pocomoke sound where both tidal currents and wave action impact sediment resuspension anomalies show a more gradual decrease with depth near the mouth of the bay where there is a higher influx of sediments from the continental shelf short wavelength anomalies are isolated and do not appear to represent heavy mineral sand concentrations these combined observations suggest the importance of further sorting by erosional processes in certain parts of the bay additionally comparisons of these data to cores sampling pre holocene sediments suggest that the sorting of heavy minerals in higher energy shallow water environments provides a mechanism for correlations between core magnetic susceptibility and sea level changes

a 16 000 year record of near field relative sea level changes northwest scotland united kingdom abstract isolation basins raised tidal marshes coastal wetlands and dune systems around arisaig in northwest scotland produce a 16 000 year record of relative sea level rsl change from the time of local deglaciation following the last glacial maximum lgm to the present new sea level index points from mointeach mhor north define the culmination of the mid holocene rsl highstand to 7600 7400 cal yr bp and 6 74 0 2 m above present numerous sea level index points indicate that the rsl highstand persisted more than 1000 years before the onset of any significant rsl fall this points to a gradual cessation of melting of the laurentide and antarctic ice sheets rather than an abrupt termination isolation basin evidence from a marine limit 34 to 38 m above present down to sites close to current sea level constrain the acceleration of eustatic sea level rise during meltwater pulse 1a to 30 mm yr 1 or 11 km 3 yr 1 meltwater discharge comparison of rsl observations with glacial isostatic adjustment gia model predictions show differences in the pattern of residuals dependent upon the gia model used changes to the far field ice model components can partly explain the patterns of residuals

preliminary study of tonsteins of the pastora formation stephanian b of the cinera matallana coalfield northwestern spain abstract the correlation of seams of the pastora formation in the cinera matallana basin is affected by facies changes seam discontinuities such as seam splitting and joining and tectonic features exploratory drillings in the matallana syncline and in an underground exposure at the northern flank of the llombera syncline prove for the first time the existence of six tonsteins the investigation provided three kaolin tonsteins one kaolinite illite transition tonstein and two illite tonsteins which are described in detail the determination of coal rank gives evidence that there is no strict co incidence with the degree of diagenesis or metamorphosis of the original volcanic ashes thus further reasons for the alteration have to be considered such as varying compositions of the original volcanic ashes biochemical and chemical processes after deposition local hydrothermal metasomatism caused by the intrusion of basic magma or tectonic stress besides known faunal and facies marker horizons these newly detected tonsteins represent first class markers within the pastora formation the possibility of using these layers for the correlation of strata and for palaeomorphological studies depends on the successful continuation of the search for additional tonsteins as well as on the compilation and evaluation of subsequent investigations

mineralogic evidence for the remnant sebennitic promontory on the continental shelf off the central nile delta abstract heavy mineral compositions of closely spaced bottom samples off the central nile delta are evaluated to determine provenance dispersal patterns and sediment sources of a former branch the sebennitic q mode factor analysis applied to heavy mineral data of 83 samples yields two factors factor 1 augite and hornblende and factor 2 opaques garnet zircon monazite rutile epidote the two factors correlate negatively with each other the observed mineralogic pattern is attributable to selective transport processes of the sediments related to a former subdelta they probably originated from extensive progradation of the remnant promontory of the extinct sebennitic branch which flowed across the subaerially exposed continental shelf during the last holocene sea level low stand grain sorting patterns of heavy minerals provide additional proof for the presence of a large sebennitic channel extending across the continental shelf off the central nile delta

holocene environmental change in the inner severn estuary uk an example of the response of estuarine sedimentation to relative sea level change holocene sediments of the wetlands around the inner severn estuary uk demonstrate a consistent stratigraphy of a single woody peat layer up to at least 4 5 m thick capped with a grey silty cla

loch lomond stadial and flandrian shorelines in the inner moray firth area scotland morphological mapping and stratigraphical investigations have identified surface and buried relict marine features in the inner moray firth area the features consist of a buried gravel layer formed during the loch lomond stadial a buried beach of early flandrian age and surface beaches and estuarine flats of mid late flandrian age analysis of the altitudes of morphological features has identified two buried and five possibly six surface glacio isostatically tilted raised shorelines the steepest shoreline is associated with the buried gravel layer and slopes down towards n20 e at a gradient of 0 20m km younger shorelines have lower gradients between 0 16 0 03m km the shoreline sequence combined with published data defines relative sea level movements in the area during the last 11000 years the inner moray firth shorelines are correlated with similar features in other areas of scotland which include the main lateglacial main buried and main postglacial shorelines

hydraulic sorting of heavy mineral grains by swash on a medium sand beach abstract hydraulic sorting of detrital mineral grains in the swash zone was investigated using data on sedimentology and flow dynamics obtained from fishermans beach on the east coast of australia the beach is characteristically reflective displaying a steep beach face composed of medium sand and virtually no surf zone samples were taken from two beds enriched in heavy minerals and from the adjacent beds above and below the mineralogy of the samples was determined and measurements of grain size and settling velocity were obtained the heavy mineral grains had both a smaller intermediate diameter and a smaller settling velocity than the light mineral grains the difference between the two mineral types was typically in the range 0 25 0 50 and 2 0 2 5 cm s 1 respectively on the basis of these sedimentological measurements alone any one of three mineral sorting mechanisms could provide a feasible explanation for the development of the heavy mineral enriched beds suspension sorting entrainment sorting or shear sorting a numerical model for swash based on the nonlinear shallow water wave theory is used to provide a quantitative description of flow dynamics in the swash zone at the time the heavy mineral enriched beds were formed for the probable wave height responsible for producing the enriched beds modeled maximum flow velocity and bed shear stress at the mid swash position reached 3 5 m s 1 and 79 51 dynes cm 2 respectively given the shallow water depths and the lack of sorting in the horizontal direction of flow suspension sorting does not seem to be of overriding importance at fishermans beach the large bed shear stresses seem to also preclude entrainment sorting because for most of the time all mineral types are predicted to be in motion this contrasts with previous studies on finer grained beaches where entrainment sorting was favored and suggests that beach type may play a role in determining the sorting mechanism operating at a particular location shear sorting was found to be feasible within the modeled flow constraints at fishermans beach but it does not provide an entirely satisfactory explanation for the observed mineral sorting patterns we contend that the inability to unequivocally identify the true sorting mechanism is more a reflection of our poor understanding of the operation of these sorting mechanisms particularly within the swash zone rather than an indication that any of these mechanisms are physically inoperative in the swash zone

changes in coastal sediment transport processes due to construction of new damietta harbour nile delta egypt abstract a combination of remote sensing field surveys and sedimentological analysis of beach sands is used to assess changes of the shorelines consequent to the construction of a harbour at damietta on the nile delta the results indicate that harbour construction and in particular the construction of two jetties that extend out from the harbour entrance have created a discontinuity in the eastward moving littoral drift imagery from landsat thematic mapper provides crude assessments of the rate of up drift accretion and down drift erosion of the shorelines despite the relatively coarse pixel size 30 m and short time scale of the monitoring period 1984 1987 1991 conventional bathymetric surveys highlight changes in the nearshore environment associated with the growth of the updrift accretionary wedge and siltation of the harbour access channel beach sediments also provide a record of the changes in erosion and accretion dominated process domains on both sides of the harbour entrance the accretionary beaches west of the western jetty having a finer mean grain size with a tendency to poorer sorting skewed to the finer fraction and preferential increase in the assemblage of low density non opaque heavy minerals the beach sands of the erosional shoreline east of the eastern jetty are characterised by coarser mean grain size with a tendency to better sorting skewed to the coarser fraction and heavy mineral assemblages dominated by opaques and high density non opaques the synergistic use of remote sensing bathymetric surveying and sedimentology provides evidence that changes have affected a much larger area than predicted at the time of harbour construction

late devensian and holocene relative sea level changes in northwestern scotland new data to test existing models abstract pollen diatom lithostratigraphic and radiocarbon data from five sites in northwestern scotland provide new data from an area previously devoid of reliable and precise information on late devensian and holocene sea level changes the sites cover a range of palaeoenvironments indicative of diversity in coastal evolution since deglaciation for each site and palaeoenvironment the reference water tide level indicative range age and tendency of sea level movement of all sea level index points are quantified to enable correlation of the diverse coastal environments the data record patterns of relative sea level change and tendencies of sea level movement from 12 ka bp to 1 ka bp this is the longest and most comprehensive published record of relative sea level change from the area the information is used to test the accuracy of existing models of relative sea level change the results are only broadly consistent with a quantitative rebound model and there is significant disagreement with empirical models during the late devensian and the early holocene

monitoring changing position of coastlines using thematic mapper imagery an example from the nile delta coastline movement due to erosion and deposition is a major concern for coastal zone management very dynamic coastlines such as sections of the nile delta coast pose considerable hazards to human use and development and rapid replicable techniques are required to update coastline maps of these areas and monitor rates of movement the synoptic capability of landsat thematic mapper imagery enables monitoring of large sections of coastline at relatively coarse 30 m spatial resolution by comparing positions of the nile delta coast in 1984 1987 and 1990 1991 mapped using a region growing image segmentation technique areas of rapid change can be identified and targeted for more detailed monitoring in the field or using higher resolution images rates of erosion and deposition can be estimated crudely and areas where change appears to be accelerating can also be identified areas of severe erosion along the nile delta coast are found to be confined to the promontories of the present day mouths of the nile at rosetta and damietta eroding shorelines are mostly flanked by accreting shorelines showing that some of the eroded material is redistributed along the coast the technique outlined here has potential to augment conventional field based surveying for monitoring shoreline changes over short timescales

diagenetic quartz and amorphous silica in new zealand coals new zealand coal seams late cretaceous miocene lignite semi anthracite contain numerous and varied occurrences of diagenetic quartz and amorphous silica early diagenetic silicifications include sub horizontal and laterally extensive quartz mineralized bands micro and megascopic euhedral quartz crystals dispersed or concentrated in layers and silicified in situ tree stumps late diagenetic forms include sub horizontal quartz mineralized bands mostly 1 m in length and fracture infillings the origins of the silica remain uncertain but leached basement rocks and coal measure sediments and siliceous phytoliths within the coal forming plants are possible sources the silicification of coal seams may have significant implications for exploration mining and geological studies

coalification history of the stephanian cinera matallana pull apart basin nw spain combining anisotropy of vitrinite reflectance and thermal modelling the stephanian cinera matallana basin of nw spain comprises 1 500 m of alluvial to lacustrine coal bearing sediments which were deposited in a late variscan transtensional transpressional pull apart setting the relationship between coalification pattern and rock deformation was evaluated by measurements of the anisotropy of vitrinite reflectance avr the avr ellipsoids reveal both pre tectonic elements related to the bedding fabric and syn tectonic elements related to folding producing biaxial ellipsoid shapes with the maximum reflectance parallel to fold axes the mean coalification gradient for the stephanian succession is about 0 62 rr km calculations of the mean palaeo geothermal gradient are presented on the basis of three different empirical equations a palaeo geothermal gradient of 85 c km is considered the most realistic with an overburden of about 1 000 m 1 d numerical modelling of the burial history results in two possible scenarios the most preferable involving a palaeo heat flow of 150 mw m2 and an overburden of ca 1 050 m these results indicate that maximum coalification was related to a localised but high palaeo heat flow geothermal gradient the anisotropy of vitrinite reflectance highlights the interactive and transitional nature of sedimentary compaction and rock deformation on the maturation of organic material within strike slip fault zones

holocene sea level changes and crustal movements in morecambe bay northwest england holocene stratigraphy from skelwith pool on the northern side of morecambe bay is described diatom and pollen analyses and radiocarbon dating have been undertaken for three sampling sites from which eight sea level index points have been obtained these index points come from a small homogeneous area and similar palaeoenvironments some published sea level index points from morecambe bay have been re evaluated and validated by means of diatom analysis an enhanced sea level database with 28 index points has been used for the reconstruction of holocene sea level history relative sea level rose rapidly around 6870 6510 bc at a maximum rate of 36 7 mm yr 1 subsequently the rate of sea level change has varied between 8 mm yr 1 and 12 mm yr 1 the rate of relative sea level changes for the last 3500 years is not clear uplift driven by deglaciation is believed to have been interrupted in the early holocene by a rapid rise in relative sea level uplift restarted at 6510 bc but soon declined as glacio isostatic recovery ended around 3800 bc in the morecambe bay area since then crustal movements in the morecambe bay area have been minimal factors affecting the attitudes of the index points such as sediment compaction of the basal peat and variations in palaeotidal range during the holocene have been considered 1996 john wiley sons ltd

relative sea level changes glacial isostatic modelling and ice sheet reconstructions from the british isles since the last glacial maximum while contributing 1 m equivalent eustatic sea level rise the british isles ice sheet produced glacio isostatic rebound in northern britain of similar magnitude to eustatic sea level change or global meltwater influx over the last 18 000 years the resulting spatially variable relative sea level changes combine with observations from far field locations to produce a rigorous test for quantitative models of glacial isostatic adjustment local ice sheet history and global meltwater influx after a review of the attributes of relative sea level observations significant for constraining large scale models of the isostatic adjustment process we summarise long records of relative sea level change from the british isles and far field locations we give an overview of different global theoretical models of the isostatic adjustment process before presenting intercomparisons of observed and predicted relative sea levels at sites in the british isles and far field for a range of earth and ice model parameters in order to demonstrate model sensitivity and the resolving power available from using evidence from the british isles for the first time we show a good degree of fit between relative sea level observations and predictions that are based upon global earth and ice model parameters independently derived from analysis of far field data with a terrain corrected model of the british isles ice sheet that includes extensive glaciation of the north sea and western continental shelf that does not assume isostatic equilibrium at the last glacial maximum and keeps to trimline constraints of ice surface elevation we do not attempt to identify a unique solution for the model lithosphere thickness parameter or the local scale detail of the ice model in order to provide a fit for all sites but argue that the next stage should be to incorporate an ice sheet model that is based on quantitative glaciological model simulations we hope that this paper will stimulate this debate and help to integrate research in glacial geomorphology glaciology sea level change earth rheology and quantitative modelling copyright 2006 john wiley sons ltd

climate and induced changes in relation to shoreline migration trends at the nile delta promontories egypt abstract an analysis of changing shoreline positions has been conducted for the rosetta and damietta nile promontories the analysis was based on several shoreline positions over the 19th and 20th centuries the shoreline positions were determined from ground surveys maps and aerial and satellite photos generally the analysis reveals two remarkable shoreline migration trends prograding shorelines during the 19th century and a more recent retrograding shoreline trend during the 20th century a relationship exists between shoreline changes nile hydrology and rainfall indicators which indicates that the change from progradation to retrogression was partly controlled by the annual fluctuation of high or low nile floods in early historical times because of climatic changes precipitation and partly by human induced changes differences in precipitation patterns in east africa altered the hydrology of the nile including the sediment load the water level and discharge a remarkable difference occurred in the nile hydrology around 1900 the prograding shoreline trends coincided with higher nile floods during the 19th century the retrograding shorelines with low floods during the 20th century

flandrian sea level changes in the fenland ii tendencies of sea level movement altitudinal changes and local and regional factors stratigraphic micropalaeontologic and radiocarbon data show that since c 6500 bp the fenland has been influenced by 7 periods of positive sea level tendencies and by 6 periods of negative sea level tendencies despite the numerous problems associated with the reconstruction of past altitudes of sea level the periods of positive sea level tendencies were clearly characterised by a rise in sea level the development of transgressive overlaps and a landward movement of the coastline the periods of negative sea level tendencies were characterised by the development of regressive overlaps a seaward movement of the coastline and a reduced or negative rate of sea level rise the various altitudinal errors do not permit the incontrovertible distinction of periods of falling sea levels all changes within the fenland were not synchronous and local factors influenced the exact nature of each sea level indicator dominant regional and local factors have been identified for different areas and different time periods the chronological and spatial characteristics of the sequences within the fenland are best explained by a palaeocoastline without supratidal barriers controlling sedimentation the data indicate an average crustal subsidence in the fenland of 0 9m 1000 years since c 6500 bp and the pattern of positive and negative tendencies of sea level movement is also seen in the chronologies for north west england and north east scotland

patterns of nearshore sediment transport along the nile delta egypt abstract the nearshore sediment transport system along the nile delta has been determined from the response of beaches to the construction of engineering structures from the forms of geomorphological shoreline features from large scale changes in shoreline orientations due to erosion and accretion and from longshore variations in beach sand mineralogy and grain sizes the analyses reveal local patterns of erosion and accretion that have resulted from the interruption of the longshore sediment transport by jetties and groins as well as the major erosion of the promontories adjacent to the mouths of the rosetta and damietta branches of the nile river brought about by the cutoff of the supply of river sand by construction of the high aswan dam major zones of shoreline accretion are positioned to the east of the eroding promontories demonstrating that there are strong longshore gradients in the quantities of the eastward sand transport the variation east of the rosetta branch has been quantitatively evaluated from the patterns of erosion and accretion based on sediment continuity considerations a similar delta wide comparison is made between the patterns of longshore sediment movements found in this study and those calculated by others from wave refraction diagrams based on the various lines of evidence for beach erosion longshore sediment transport and shoreline accretion four nearly self contained cells have been identified in the littoral zone of the nile delta abu quir bay the eastern flanks of the rosetta and damietta promontories and the burullus central delta region