sediment transport predictions for the english channel using numerical models output from an hydrodynanmic numerical model salomon breton 1991 a b has been combined with various empirical formulae to derive sediment transport rates and directions the predictions are compared with radioactive sand tracer experiments demonstrating the applicability of gadd et al s 1978 expression the derived bedload transport pattern for the area is consistent with sedimentological and geomorphological evidence but provides improved resolution a bedload parting zone is identified for the central english channel this is well defined for sand movement but seabed material present over this area gravel is not predicted to move significantly the area is non erosive over which fine grained sediments are being transported a bedload convergence is located to the southwest of the dover strait not in the strait itself as proposed previously a transport pathway bypassing the convergence along the french coastline which is supported by radioactive tracer experiments could be responsible for sand transfer from the english channel to the southern north sea

common millennial scale variability of antarctic and southern ocean temperatures during the past 5000 years reconstructed from the epica dome c ice core measurements of the two water stable isotopes dd and d18o along epica european project for ice coring in antarctica dome c ice core are combined with simple isotopic modelling distillation models to reconstruct the variability of both the site temperature east antarctica and the moisture source temperature nowadays probably the subantarctic indian ocean we discuss the difference between the reconstructed site and source temperature pro les with respect to the initial isotopic data we show that i the early holocene optimum appears rst in antarctica and 800 years later in the southern ocean and ii during the last 5000 years the site and source temperatures co vary at the centennial timescale an 833 year periodicity is observed only on deuterium and site temperature and therefore probably of local origin

revisiting the late permian coal from the huayingshan sichuan southwestern china enrichment and occurrence modes of minerals and trace elements abstract the late permian coals from the huayingshan coalfield of southwestern china are significantly enriched in zr 695 g g nb 75 9 g g se 6 99 g g hf 10 1 g g and rare earth elements and y 1423 g g previous studies showed that the sediment source region for these coals was the kangdian upland which was formed at an early stage of the late permian period the source rocks have a basalt composition and those studies attributed the enrichment of the above high field strength elements hfses to derivation from the kangdian upland geochemical and mineralogical data presented in this study show that the dominant sediment source regions for the coal and roof strata of the huayingshan coalfields are the dabashan uplift hannan upland and leshan longnvsi uplift the highly elevated concentrations of hfses in the coals are due to hydrothermal fluids three tonstein layers derived from alkali rhyolite were identified these tonsteins are characterized by highly enriched hfses and by strong negative eu anomalies in the rare earth element distribution patterns the major carriers of the rare earth elements in the coal are rhabdophane and silicorhabdophane the latter of which is also enriched in zr zirconium however mainly occurs in zircon rhabdophane and silicorhabdophane in the coal are mainly distributed along the bedding planes and occur as cell fillings zircon in the coal occurs as cell fillings and is of authigenic origin anatase in the partings and coals contains nb and occurs as fracture filling and colloidal forms the modes of occurrence of the above minerals indicate that they were derived from hydrothermal fluids mercury and se mainly occur in sulfide minerals pyrite and marcasite

holocene climate in the atlantic sector of the southern ocean controlled by insolation or oceanic circulation abstractthe holocene climate of the southern ocean is not well un derstood mainly because of the lack of high resolution reconstruc tions of ocean surface properties here we present a 12 500 yr long decadal scale record of holocene sea surface temperatures and sea ice presence from the polar front of the east atlantic southernocean the record shows gradual climate change with no abruptneoglacial cooling and an unprecedented late holocene warming the dominant forcing factor appears to be precessional insolation northern hemisphere summer insolation correlates to at least theearly to middle holocene climate trend spectral analysis revealscentennial scale cyclic climate changes with periods of 1220 1070 400 and 150 yr the record shows good correlation to east ant arctic ice cores and to climate records from south georgia andbunger oasis however the record shows out of phase behaviorwith regard to climate records from the western antarctic penin sula and the peru chile current such behavior hints at a climaticdivide through patagonia the drake passage and between westand east antarctica keywords southern ocean paleoclimate diatoms modern analogtechnique holocene insolation antarctic polar front introductionthe holocene climate variability has received less attention thanthe more dramatic changes during the last glacial period the holoceneis generally assumed to be a stable interglacial period when climatechanges in the north atlantic are transmitted to the rest of the worldthrough a strong thermohaline circulation imbrie et al 1992 thelarge uctuations of the last glacial period appear to continue into thisinterglacial although in a subdued manner bond et al 2001 the southern ocean has received even less attention than the highnorthern latitudes oceanic records are few and coarse they generallydisplay a warm early holocene followed by cooling labracherie etal 1989 pichon et al 1992 hodell et al 2001 similar to northatlantic climate e g koc and jansen 1994 high resolution recordsare restricted to antarctic ice cores which mostly display little climatevariability during the holocene jouzel et al 2001 an exception isthe taylor dome deuterium record in which the holocene appears tobe split by an abrupt cooling event ca 5 5 5 ka steig et al 1998 this cooling appears to t the late holocene global cooling trend por ter 2000 as a nonlinear response from the climate system to insolationchanges demenocal et al 2000 hodell et al 2001 high resolution holocene records available for southern oceanclimate reconstruction are rarely from the antarctic circumpolar cur rent proper e g domack et al 2001 stenni et al 2001 lamy et al 2002 with the exception of a multiproxy approach to holocene cli mate that includes a high resolution description of lithic fragments hodell et al 2001 we present data from site tn057 17 near the polar front in theeast atlantic southern ocean it is based on quantitative estimates ofsummer sea surface temperature ssst and sea ice presence sip utilizing the down core variability of diatom assemblages the recordshows good correlation to antarctic ice cores but a gradual change inphase relationships during the early holocene the record shows anin phase relationship with the ross sea region ice cores during thelate holocene the record shows an in phase relationship with the eastantarctic region ice cores antarctic polar frontthe antarctic polar front apf fig 1 is an important climateboundary in terms of air sea uxes and the heat and salt budgets ofthe oceans at the surface the apf is a steep sea surface temperaturegradient while the subsurface expression is the southern limit for sub duction of cold fresh antarctic surface water below warmer and moresaline subantarctic surface water orsi et al 1995 globally the apfcould be the southern limit of synchrony with northern hemisphereclimate broecker 1996 the apf is subject to large spring and sum mer blooms of diatoms fischer et al 2002 and achieves the largestbiogenic sedimentation rates of the diatom ooze belt of the southernocean burckle and cirilli 1987 it is these high sedimentation ratesof diatomaceous oozes and the sensitivity of diatoms especially to lightand temperature that make sites in the apf region suitable for pro ducing high resolution records of climate change

organic and inorganic associations of rare earth elements in central appalachian coal abstract coal contains trace amounts of rare earth elements ree they are either in the form of discrete minerals or chemically bound to organic matter methods of distinguishing the organic and inorganic associations of ree in coal have been mostly based on the correlations between the ree concentrations and the ash yields quantitative characterization of organically associated ree is still very challenging in this work we confirm the existence of organically associated ree in coal and present an approach to quantifying its mass fraction the coal sample used in this study was a cleaned low ash coal collected from a coal preparation plant in kentucky usa and originally from the central appalachian basin coal region the results from particle size and density separations of the coal suggested that the ree are associated with both organic and inorganic matters it was found that as the ash yield increases both the total ree concentration on the whole coal basis and the lree hree ratio increase while the total ree concentration on the ash basis reduces dramatically the results also suggested that the organic matter is relatively enriched in hree based on these observation and findings a method was developed to quantitatively determine the distribution of ree in the organic and inorganic phases of the coal it was found that the total ree concentrations in the organic and inorganic phases are 31 ppm and 1141 ppm respectively the results also showed that in the low ash appalachian coal sample used in this work 25 of the ree is associated with the organic matter the method developed in this work for quantitative evaluation of the organic inorganic mode of occurrence may be applied to other coal samples and for many other trace elements in coals

deglacial seasonal and sub seasonal diatom record from palmer deep antarctica the antarctic peninsula is one of the most sensitive regions of antarctica to climate change here ecological and cryospheric systems respond rapidly to climate fluctuations a 4 4m thick laminated diatom ooze deposited during the last deglaciation is examined from a marine sediment core odp site 1098 recovered from basin i palmer deep western antarctic peninsula this deglacial laminated interval was deposited directly over a glaciomarine diamict hence during a globally recognised period of rapid climate change the ultra high resolution deglacial record is analysed using sem backscattered electron imagery and secondary electron imagery laminated to thinly bedded orange brown diatom ooze near monogeneric hyalochaete chaetoceros spp resting spores alternates with blue grey terrigenous sediments open water diatom species these discrete laminae are interpreted as austral spring and summer signals respectively with negligible winter deposition sub seasonal sub laminae are observed repeatedly through the summer laminae suggesting variations in shelf waters throughout the summer tidal cycles high storm intensities and or intrusion of circumpolar deep water onto the continental shelf introduced conditions which enhanced specific species productivity through the season

late pleistocene and holocene sedimentation on the george v continental shelf east antarctica abstract climatically controlled glaciological and oceanographic environmental changes off the george v coast during the late pleistocene and holocene have been reconstructed from changes in sedimentation processes the evolution of a sediment drift deposit mertz drift located in the deep trough on the shelf has been assessed using a sedimentological approach up to 5 5 m long cores have been collected four late pleistocene to holocene sediment units have been distinguished on the basis of their physical properties grain size distributions geochemical characteristics and ages the basal unit 1 is a grey sandy clayey diamicton 27 37 wt sand deposited before 14 000 14 c yr before present 14 c yr bp unit 1 represents a late pleistocene sub ice shelf water lain till overlain by a thin current winnowed sandy sub unit unit 2 is a massive siliceous sandy mud 11 30 wt sand rich in ice rafted debris deposited between about 14 000 and 5000 14 c yr bp it likely represents an open marine setting proximal to a retreating ice front where strong bottom currents were frequent the overlying unit 3 is a laminated siliceous mud and diatomaceous ooze with less terrigenous material 4 5 wt average sand deposited between 5000 and 3000 14 c yr bp the low wet bulk density values 3 and mass specific magnetic susceptibility values 8 m 3 kg of sediments of unit 3 are a consequence of the high content of biogenic material c org content 1 wt biogenic opal averaging 55 wt unit 3 is probably related to a phase of increased sediment accumulation on the drift site and low bottom current activity on the shelf with a stratified upper water column that could have lead to an enhanced primary productivity occurrence of crossed lamination indicates episodes of slightly enhanced bottom currents probably with velocities up to 3 5 cm s the top unit 4 is a bioturbated siliceous sandy mud on average 50 cm thick deposited under an energetic bottom current regime after about 3000 14 c yr bp this regime is probably related to the activation of a brine rejection mechanism and is linked to the formation of high salinity shelf water hssw in a coastal polynya which causes winnowing of the shelf deposits in contrast the mid holocene setting was characterised by weaker bottom currents that together with high inputs of organic material from the photic zone allowed for the deposition of thick fine grained sediments of unit 3 resulting in an anoxic environment

long term marine bedload segregation and sandy versus gravelly holocene shorelines in the eastern english channel abstract retreating cliffs comprising fringing gravel or sandy beaches line much of the english and french coasts in the eastern english channel locally gravel has formed significant barrier accumulations overlying thick finer grained deposits although sandy deposits are abundant on the bed of the eastern channel significant aeolian dunes are restricted to embayments on the west facing french coast between the somme estuary and cape gris nez these embayments show holocene continuity of deposition of relatively homogenous sand with the dunes overlying beach washover and estuarine sediments it is argued that the occurrence of gravelly shorelines or of sandy shorelines exhibiting significant aeolian dunes largely reflects a combination of three factors 1 the inherited coastal lithology and morphology characterised by soft rock cliffs with or without embayments that were potential holocene sediment sinks 2 coastal orientation relative to large scale tide and wind driven marine bedload segregation processes that operated during the holocene and have led to preferential sand concentrations in the eastern corner of the channel and possibly concomitant relative enrichment in nearshore gravel elsewhere 3 coastal orientation relative to the synoptic westerly wind field responsible for significant aeolian dune building where such sand concentrations occurred the only coast where these three conditions were met favourably for significant aeolian dune building is the west facing french coast north of the somme estuary which benefitted during the holocene from large scale eastward advection of sand from the bed of the channel this sand was concentrated along a well defined coast parallel transport pathway driven by tidal currents enhanced by coriolis forcing and especially by the coast orthogonal synoptic westerly winds as sea level rise slowed or stabilised following the middle holocene the sand was piled onshore in embayments to form aeolian dunes by these coast orthogonal winds leaving no scope for the formation of gravel shorelines this coastal sand transport pathway is still operational elsewhere the inherited coastal morphology and orientation in terms of both the coriolis effect and westerly wind forcing have not favoured similar large scale sand trapping in coastal sinks as a result the shorelines are characterised by retreating cliffs and fringing beaches with a few major gravel barriers formed in local downdrift sinks and comprising clasts reworked by storms from offshore gravel deposits on the bed of the channel and from cliff retreat the sharp change in facies from fine grained sediments to overlying gravel within these barriers may have been enhanced by sand depletion caused by the large scale holocene bedload segregation processes that operated in the eastern channel it is suggested that if the permanence of the present day 3 d morphology of the eastern english channel and the same hydrodynamic forcing notably the same wind field as during the holocene are accepted then the suggested model of coastal sedimentation involving preferential large scale drift of channel bed sand towards the north south oriented french coast north of the somme estuary would also predict permanent dominantly gravelly high sea level beach sedimentation on the opposite english coast

antarctic sea ice and palaeoproductivity variation over the last 156 000 years in the indian sector of southern ocean abstract antarctic sea ice plays a vital role in global climate via its impact on ocean circulation biological productivity and co2 partitioning between the ocean and the atmosphere however very little is known about its past history especially in the southwestern indian sector of the southern ocean so we here provide new quantitative records of winter sea ice concentration wsic and duration wsid sea surface temperatures sst and productivity in sediment core sk 200 33 55 s 45 e from the permanently open ocean zone over the last 156 000 years the new records combined with regional records indicate that the hydrological structures migrated northward by a few degrees of latitude during all glacial periods with the southern antarctic circumpolar current front reaching the core site the antarctic polar front located at 46 s and the winter sea ice wsi probably extending to 49 s in contrast hydrological fronts and wsi edge migrated poleward by a couple of degrees of latitude during the early holocene and last interglacial comparison to sst and wsi records from different sectors of the so suggests higher amplitude variations in wsi in the atlantic sector as compared to the indian and western pacific sectors over the last glacial interglacial cycle which we attribute to the presence of the weddell gyre transporting far to the north the sea ice produced in the weddell sea the new records also suggest a drop in productivity in the pooz during glacial periods probably related to greater wsi extent and reduced growing season

deglacial ocean and climate seasonality in laminated diatom sediments mac robertson shelf antarctica the palaeoceanography and climate history of the east antarctic margin eam are less well understood than those of west antarctica yet the eam plays an important role in deep ocean circulation and the global ocean system and has likely done so in the past deglacial age marine sediments from the eam provide clues about its past role during this critical period of rapid climate change several deep basins across the eam such as iceberg alley 67 s 63 e on the mac robertson shelf mrs accommodate thick marine sequences that archive the deglaciation in the form of diatom rich continuously laminated varved sediments these laminated sediments are pristinely preserved and contain seasonal and long term information on the cryospheric and palaeoceanographic changes associated with the rapid retreat of the glacial ice sheet across the mrs we present results of microfabric analysis of the lower 2 m of deglacial varves from jumbo piston core jpc43b iceberg alley backscattered electron imagery bsei of polished thin sections and scanning electron microscope secondary electron imagery sei of lamina parallel fracture surfaces are used to analyze the varves one hundred and ninety two laminations are investigated and their nature and temporal significance are discussed in terms of seasonal deposition and cyclicity of diatom species our high resolution palaeodata record exceptionally high diatom production and silica flux associated with the retreat of the east antarctic ice sheet and seasonal sea ice changes along the eam this information is invaluable for assessing cryospheric oceanographic variation and therefore the local and regional response to this period of rapid climate change varves are made up of lamina couplets comprising i thickly laminated to thinly bedded orange orange brown very pure diatom ooze dominated by hyalochaete chaetoceros spp vegetative cells and resting spores and ii brown blue grey terrigenous angular quartz sand silt and clay with an abundant mixed diatom flora the colour variation between these two types of lamination is striking using floristic and textural information we interpret the diatom oozes as spring flux and the terrigenous laminae as summer flux each couplet pair represents one annual cycle and reflects seasonal changes in nutrient availability and stratification associated with the cyclical advance and retreat of seasonal sea ice the diatom oozes can reach up to 7 5 cm in thickness indicating enormous silica flux to the sea floor associated with ice sheet retreat

late pleistocene holocene marine conditions in the ross sea antarctica evidence from the diatom record statistical analyses of diatom assemblages from radiocarbon dated sediment cores were used to reconstruct changing palaeoceanographic conditions in the western and west central ross sea antarctica from c 12 14c kyr bp to the present data from three kasten cores support a north to south time transgressive glacial interglacial transition assemblages at the base of each core suggest that glacial processes affecting frustule preservation were significant during the late pleistocene increasing biogenic silic and decreasing per centages of reworked species suggest that upper water column productivity instead of preservational processes increasingly dominates diatom assemblages during grounding line recession c 12to c 6 14c kyr bp a warm ing during the middle to late holocene c 6to c 3 14c kyr bp may have resulted in a spring sea ice melting prior to the annual inception of the ross sea polynya in the west central ross sea and b increased plateletice delivery due to increased melting beneath t

analysis origin and significance of mineral matter in coal an updated review abstract the material classed as mineral matter in coal embraces crystalline mineral materials as well as a range of inorganic elements that occur in non crystalline form this review outlines the methods that may be used to evaluate the percentage of mineral matter for a coal sample as opposed to the ash yield and to identify the minerals their individual percentages and their modes of occurrence within the coal the principal techniques include low temperature oxygen plasma ashing quantitative evaluation of x ray diffraction data observation using optical microscopy and a combination of observation chemical analysis and in some cases mapping based on scanning electron microscopy and related methods a range of other techniques may also be used to provide additional information on particular mineral matter components processes responsible for mineral matter formation include detrital input biogenic activity and authigenic precipitation at different stages of the coal s depositional and post depositional history differential migration of non mineral inorganic elements may also occur in lower rank coals and expulsion of non mineral inorganics may take place with rank advance knowledge of the mineral matter may be of assistance in understanding the modes of trace element occurrence with implications for assessing possible environmental impacts and also the potential for recovery of economic products from coal the behaviour of different mineral matter components at high temperatures is also discussed as well as methods for mineralogical analysis of ashes and other coal utilization products information from mineral matter studies may provide an improved basis for understanding coal formation and for evaluating the response of particular coals to different combustion gasification and coking processes

abrupt cooling of antarctic surface waters and sea ice expansion in the south atlantic sector of the southern ocean at 5000 cal yr b p antarctic surface waters were warm and ice free between 10 000 and 5000 cal yr b p as judged from ice rafted debris and microfossils in a piston core at 53 s in the south atlantic this evidence shows that about 5000 cal yr b p sea surface temperatures cooled sea ice advanced and the delivery of ice rafted detritus ird to the subantarctic south atlantic increased abruptly these changes mark the end of the hypsithermal and onset of neoglacial conditions they coincide with an early neoglacial advance of mountain glaciers in south america and new zealand between 5400 and 4900 cal yr b p rapid middle holocene climate changes inferred from the taylor dome ice core antarctica cooling and increased ird in the north atlantic and the end of the african humid period the near synchrony and abruptness of all these climate changes suggest links among the tropics and both poles that involved nonlinear response to gradual changes in northern hemisphere insolation sea ice expansion in the southern ocean may have provided positive feedback that hastened the end of the hypsithermal and african humid periods in the middle holocene

mineralogical and geochemical anomalies of late permian coals from the fusui coalfield guangxi province southern china influences of terrigenous materials and hydrothermal fluids abstract the late permian coal in the fusui coalfield of southern china is characterized by high fe sulfide and organic sulfur contents 2 60 and 2 94 respectively trace elements including zr 354 g g on average hf 9 18 g g y and rare earth elements rey 302 g g li 97 9 g g and cs 7 02 g g are significantly enriched in these coals in addition to hg and se enrichment in the roof and floor of the coal fluorine mo and u are enriched in the roof the floor is rich in cl s fe pb and cd compared to the upper continental crust rey in the parting and coal bench samples are characterized by heavy rey and light rey enrichment respectively the coals partings and host rocks roof and floor have negative eu anomalies the coal benches have higher ratios of u th yb la nb ta and zr hf and more abundant heavy rare earth elements than their adjacent partings these geochemical anomalies are attributed to the composition of terrigenous materials derived from the yunkai upland multi stage syngenetic and epigenetic hydrothermal fluid activities and intensive leaching and re distribution of lithophile elements from partings to the underlying coal benches both the organic and sulfide sulfur are also derived mainly from the hydrothermal fluids rather than the marine influence the minerals in the samples studied including kaolinite quartz and ree bearing minerals are of both terrigenous and hydrothermal origin al oxyhydroxides crystalline feso 4 oh water bearing fe oxysulfate and goyazite were derived from the hydrothermal activity kaolinite quartz ree bearing minerals and apatite from the sediment source region were also subjected to destruction by hydrothermal fluid leaching

last glacial sea surface temperatures and sea ice extent in the southern ocean atlantic indian sector a multiproxy approach 1 on the basis of the quantitative study of diatom radiolarian and planktic foraminiferal assemblages we estimated summer sea surface temperature ssst and sea ice extent at 50 sediment core localities in the atlantic and western indian sector of the southern ocean to reconstruct the last glacial environment at the glamap 18 to 15 ka equal to 21 500 to 18 000 calendar cal years bp and epilog 19 5 to 16 0 ka equal to 23 000 to 19 000 cal years bp time slices stratigraphic identification of the time slices was accomplished by a combination of ams 14c measurements benthic isotope and siliceous microfossil abundance records while the ssst estimates reveal greater surface water cooling than reconstructed by climap 1981 reaching a maximum in the area of the present subantarctic zone the sea ice reconstruction indicates that climap overestimated the expansion of the antarctic sea ice field especially for austral summer during winter the sea ice field was expanded by 60 70 compared to the present last glacial summer sea surface isotherms indicate a northward shift of the zonal bands of the antarctic circumpolar current and a relative expansion of the cold water realm south of the subantarctic front by 5 in latitude this coincides with a northward displacement of the zone of enhanced biogenic silica deposition and iceberg occurrence as a result of northward expansion of antarctic cold waters and a relatively small displacement of the subtropical front thermal gradients were steepened during the last glacial in the area of the present subtropical front the northward displacement of antarctic cold waters and the related deflection of southern ocean waters along the eastern boundary of south america may have resulted in a weakened cold water route across the drake passage in contrast the transport of warm and salty surface water from the indian into the atlantic ocean via the warm water route was not blocked allowing continuous but reduced import of heat into the south atlantic

recent shoreline mobility and geomorphologic evolution of macrotidal sandy beaches in the north of france abstract this paper examines shoreline mobility and sediment budget conditions on a sandy macrotidal coast with a well developed foredune aerial photographs and bunker archaeology covering the last 50 years were analysed in order to determine the meso scale evolution of le touquet beach in northern france both methods show that shoreline retreat has been negligible or very slow and has been accompanied by an elevation of the foredune dgps cross shore profiles show a balanced sediment budget over the last 7 years only a slight change of the beach face profile 0 2 0 5 m rise or fall was observed while the foredune exhibited a sharper change the french coast of the eastern english channel differs from that of the french atlantic coast which is currently being strongly eroded the balanced sediment budget of the former is attributed to sand inputs from nearshore banks which compensate exports due to longshore drift and to foredune development

holocene paleoclimate change in the antarctic peninsula evidence from the diatom sedimentary and geochemical record abstract holocene marine deposition in lallemand fjord antarctic peninsula is reinterpreted using statistical analyses cluster analysis analysis of variance nonmetric multidimensional scaling and multiple regression to compare diatom assemblages and the primary sedimentological proxies the assemblages have been deposited in a variable sea ice zone over the last ca 10 500 yr bp in response to a climate change in the late pleistocene early holocene 10 580 7890 yr bp a sea ice diatom assemblage was deposited in the presence of a retreating ice shelf at the head of the fjord in the mid holocene 7890 3850 yr bp an open water assemblage was deposited and sea ice cover was at a minimum we associate the assemblage with climatic warming which characterizes much of the antarctic peninsula during this time a second sea ice assemblage different from that deposited in the early holocene has been deposited in lallemand fjord since the late holocene

seasonal and subseasonal climate changes recorded in laminated diatom ooze sediments adelie land east antarctica a 40 m long sediment core covering the 1000 9600 years bp period was retrieved from the dumont d urville trough off adelie land east antarctica during the md 130 images x cado cruise this sedimentary sequence allows the documentation of changes in climate seasonality during the holocene here we show preliminary results of diatom communities lithic grain distribution and titanium content measured on two 30 cm long sequences of thin sections the two sequences originate from two different climate regimes the colder neoglacial and the warmer hypsithermal proxies were measured at microscale resolution on 25 laminations for the neoglacial and 14 laminations for the hypsithermal the two sequences reveal alternating light green and dark green laminae light laminae result from low terrigenous input and high sea ice edge diatom fluxes and are interpreted to represent the spring season dark laminae result from high terrigenous input mixed with a diversified open ocean diatom flora and are interpreted to represent the summer autumn season the two sequences therefore resolve annual couplets composed of one light plus one dark lamina variations in the relative thickness of laminations and annual couplets associated with diatom assemblage changes are observed in each sequence and between the two sequences giving information on interannual to millennial changes in environmental conditions

productivity cycles of 200 300 years in the antarctic peninsula region understanding linkages among the sun atmosphere oceans sea ice and biota compared to the rest of the world9s oceans high resolution late holocene paleoclimatic data from the southern ocean are still rare we present a multiproxy record from a sediment core retrieved from a deep basin on the western side of the antarctic peninsula that reveals a dramatic perspective on paleoclimatic changes over the past 3700 yr analyses completed include measurement of magnetic susceptibility and granulometry bed thickness particle size percent organic carbon bulk density and microscopic evaluation of diatom and benthic foraminiferal assemblages and abundances downcore variability of these parameters demonstrates the significance of both short term cycles which recur approximately every 200 yr and longer term events 2500 yr cycles that are most likely related to global climatic fluctuations in the upper 600 cm of the core lower values of magnetic susceptibility ms are correlated with lower bulk density the presence of thinly laminated units specific diatom assemblages and generally higher total organic carbon content below 600 cm magnetic susceptibility is uniformly low though variability in other parameters continues the magnetic susceptibility signal is controlled primarily by dilution of ferromagnetic phases with biosiliceous material this signal may be enhanced further by dissolution of magnetite in the magnetic susceptibility lows high total organic carbon the role of variable primary productivity and its relationship to paleoclimate is assessed through the diatom data in particular magnetic susceptibility lows are characterized by higher than normal abundances of chaetoceros resting spores corethron criophilum and or rhizosolenia spp also are found as is a higher ratio of the most common species of fragilariopsis versus species of thalassiosira these assemblages are indicative of periods of high primary productivity driven by the presence of a meltwater stabilized water column the 200 yr cyclicity noted in other paleoclimatic records around the world suggests a global forcing mechanism possibly solar variability in addition to the cyclic changes in productivity overall elevated productivity is noted below 600 cm or prior to ca 2500 yr b p this increased productivity may represent the tail end of a holocene climatic optimum which is widely recognized in other parts of the world but as yet is poorly documented in antarctica

geochemistry of rare earth elements in permian coals from the huaibei coalfield china abstract the rare earth elements rees in coals are important because of a ree patterns can be an indicator of the nature of source rocks of the mineral matter as well as sedimentary environments b rees abundance in coal may have industrial significance in this study a total of thirty four samples of permian coal partings roof and floor were collected from the huaibei coalfield anhui province china abundances of rare earth elements rees and other elements in the samples were determined by inductively coupled plasma mass spectrometry icp ms and inductively coupled plasma atomic emission spectrometry icp aes the results show that the rees are enriched in coals in the huaibei coalfield as compared with chinese and u s coals and the world coal average coals in the lower shihezi formation no 7 5 and 4 coals and upper shihezi formation no 3 have higher ree abundances than the coals in shanxi formation no 10 magmatic intrusion resulted in high enrichment of rees concentrations in no 5 and 7 coals the ree abundances are positively correlated with the ash content the mineral matter in these coals is mainly made up of clay minerals and carbonates the rees are positively correlated with lithophile elements including si al ti fe and na which are mainly distributed in clay minerals indicating that rees are contained mainly in clay minerals the ree abundances in coals normalized by the ash are higher than that in partings rees abundances of coals cannot be accounted for by the ree content in the mineral matter and some rees associated with organic matter in coals

rare earth elements in bituminous coals and underclays of the sydney basin nova scotia element sites distribution mineralogy abstract bituminous coals of the sydney basin nova scotia canada contain some 30 ppm of rare earth elements ree dispersed in illite clay and macerals or concentrated in fossil apatite and resistate minerals monazite florencite xenotime zircon for high ash coals the bulk of ree are derived from suspended river sediments low ash bituminous coals contain some heavy ree complexed with the organic phase or adsorbed by authigenic clays and derived largely from dissolved river load the concentration of ree in coal ash 72 to 483 ppm is similar to that of roof and seat clays except for slight local enrichments in heavy ree individual seams have diverse ree distribution patterns that reflect the depositional and diagenetic mineralogy or reveal enrichment at seam margins by organic complexing or fossil apatite uptake chondrite normalized profiles range from light ree enriched to heavy ree enriched highly pyritized bands yield ash low in ree with flat profiles clay rich bands yield ash with distribution patterns similar to shales with light ree enrichment a weak negative eu anomaly and a profile slope correlated to al content rare earth element partitioning between organic and mineral phases or between coals and associated strata differs over the coalfield reflecting the combined effects of sedimentation water chemistry ion exchange and chelation coal seam correlation using ree distribution is limited by geochemical facies distribution patterns must be interpreted with caution because of analytical problems inherent to coal

antarctic sea ice and the control of pleistocene climate instability a hypothesis is presented for the origin of pleistocene climate instability based on expansion of antarctic sea ice and associated changes in the oceans salinity structure the hypothesis assumes that thermohaline overturning is dominated by the reconfigured conveyor of toggweiler and samuels 1993b in which deepwater upwelling is restricted to high southern latitudes the reconfigured conveyor is shown to be potentially stabilized in an on mode by precipitation at high southern latitudes and potentially destabilized into on and off modes by the counteracting influence of antarctic sea ice the mechanism is clarified by the use of a hydraulic analogue we hypothesize that this mechanism accounts for dominant patterns of thermohaline overturning and climate instability between pleistocene warm and cold periods the hypothesis is shown to be consistent with a range of paleoceanographic evidence and to potentially account for details of observed rapid climate changes during glacial and interglacial periods including aspects of interhemispheric timing

late quaternary sea ice history in the indian sector of the southern ocean as recorded by diatom assemblages abstract a modern analog technique mat5201 31 has been applied to fossil diatom assemblages to provide down core estimates of february sea surface temperatures ssts and of sea ice duration over the past 220 000 years at 56 40 s 160 14 e at the core location sea ice progression lagged the sst drop by 1 ka at interglacial glacial transitions and sea ice retreat was almost synchronous to the sst increase at glacial interglacial terminations sea ice increased continuously during glacial periods to reach its maximum extent at the end of glacial times although ssts were almost constant during glacials this indicates that ssts are the major parameter determining the advance and retreat of sea ice at transitions but that the sea ice advance during glacial conditions may be related to positive feedbacks of the ice on albedo air temperature and meridional wind stress the strong correlation r 0 75 between sea ice duration at the core location and the vostok co2 record argues for a control of antarctic sea ice extent on atmospheric co2 concentration via the modification of the ocean to atmosphere gas balance

the southern ocean surface between marine isotope stages 6 and 5d shape and timing of climate changes summer sea surface temperature ssst and sea ice extent obtained at millennial to centennial resolution are presented for seven cores recovered in the atlantic and western indian antarctic zone from termination ii and the last interglacial s s i e marine isotope substage mis 5e the diatom based ssst estimates show that during the late mis 6 intensified export of cold waters from the weddell sea resulted in sssts close to 0 c in the central and eastern atlantic sector due to northward expansion of the winter sea ice edge by 3 5 latitude the sea ice seasonality was reduced such conditions have great potential for efficient year round reduction in air sea gas exchange and glacial co2 draw down the warming at termination ii started at 132 131 ka marked by rapid retreat of the sea ice edge the ssst increased within a few thousands of years to reach maximum interglacial summer temperatures ranging between 2 5 and 3 5 c in the earliest mis 5e 128 125 ka besides a distinct cold reversal around 129 5 ka the warming was punctuated by short lived temperature rebounds with amplitudes of 1 1 5 c occurring at 200 300 yr frequency thus in the range of the periodicity of solar input increased chaetoceros spp abundance suggests meltwater events as the primary cause of the coolings the ssst optimum characterised by strongly enhanced biogenic sedimentation rates ended at ca 125 ka with the full re establishment of the global conveyor belt and beginning of the northern hemisphere climatic optimum at this time sssts decreased stepwise and stabilised on values slightly warmer than today showing in the following period of mis 5e only low amplitude oscillations during mis 5d a northward expansion of the sea ice field took place but sssts only slightly colder than modern ones and a weakened meridional temperature gradient indicate that the southern ocean did not fall in a true glacial mode the tight correlation between southern ocean ssst and winter sea ice records and vostok atmospheric temperature and co2 records support the idea that the antarctic winter sea ice and southern ocean temperature exert a primary control on the atmospheric ocean co2 exchanges and hence on global climate reduction of the antarctic sea ice field and increase of ssst at the onset of termination ii could have been triggered by precessional changes influencing southern high latitude summer insolation positive feedback mechanisms reduction of surface albedo and release of co2 into the atmosphere and changes in global ocean circulation affected by a collapse or strong reduction in north atlantic deep water nadw production could have induced further reinforcement of the southern ocean warming

interpretation of recent antarctic sea ice variability 1 trends in the satellite derived antarctic sea ice concentrations 1979 2002 show pronounced increase decrease in the central pacific sector bellingshausen western weddell sector by 4 10 per decade confidence levels for these regional trends exceed 95 positive polarities of the antarctic oscillation aao lead to more less ice in the eastern ross amundsen sector bellingshausen northern weddell sector which are qualitatively opposite to the impacts of positive polarities of the el nino southern oscillation enso the mechanisms responsible for the covariability between the ice and the a aao and b enso are demonstrated over the last 24 years a positive aao trend and a slightly negative enso trend produce a spatial pattern of ice changes similar to the regional ice trends however the magnitude of the ice changes associated with the aao and enso is much smaller than the regional ice trends more local or less understood large scale processes should be investigated for the explanations

climate evolution at the last deglaciation the role of the southern ocean abstract two sediment sequences recovered close to and south of the present polar front 50 53 s in the atlantic sector of the southern ocean were analysed in order to evaluate the environmental evolution of the southern ocean surface over the last deglaciation and the holocene our reconstruction is based on radiocarbon dated records of diatom based sea surface temperature and sea ice proxies and planktic foraminiferal stable isotopes the onset of the deglacial warming and gradual southward retreat of the winter sea ice field between 18 and 17 cal kyr bp occurrence of a thermal reversal centered at ca 13 cal kyr bp antarctic cold reversal or acr and early holocene occurrence of the climatic optimum well correlate with climatic reconstructions available from the indian southern ocean and from antarctic ice cores time correspondence of southern ocean warming and heinrich event 1 in the north atlantic is compatible with the transmission of the climate signal from the northern to the southern hemisphere through the bipolar seesaw our data support modeling results suggesting that the northern hemisphere bolling warming and turn on of the north atlantic deep water formation are triggered by gradual warming and sea ice retreat in the southern ocean meltwater shedding into the southern ocean associated with the acr may maintain northern hemisphere warming during the allerod the development of sea surface warming and sea ice retreat is compatible with a southern ocean control on the atmospheric co2 increase during the deglaciation during the early holocene 9 7 cal kyr bp our southern core records renewed surface ocean cooling and northward readvance of the winter sea ice field such early holocene cooling is common to cores from the high latitude atlantic sector and might be brought about by expansion of the weddell gyre circulation at that time

rare earth elements in a sampled coal from the pirin deposit bulgaria abstract rare earth elements la ce sm eu tb yb and lu in a columnar section of the coal of the pirin deposit bulgaria have been determined by neutron activation analyses the ree content in the coals is lower than the average ree content of shales from north america europe and the soviet union the ree abundances increase with the increasing ash content of the coals the bottom of the seam is slightly enriched in ree the trend being more pronounced in hree tb yb lu the ree content depends on the thickness of the coal layers the thin coal layers are enriched in ree as compared to the thick ones the chondrite normalized distribution patterns are very uniform they are characterized by a negative eu anomaly whose mean value is 0 30 varying in the individual samples from 0 21 to 0 49 and a positive lu anomaly it is supposed that the eu anomaly is inherited from the source rocks the shale normalized distribution patterns show a distinct relative enrichment in hree and a negative eu anomaly the relative enrichment in hree is a specific feature of the ree geochemistry in the pirin deposit the lree hree ratio is lower than that of composite shale it increases with the increasing ash content of the coals and from the bottom to the top of the coal bed ree are bound predominantly to the aluminosilicates of the mineral matter in the coals all ree are positively correlated to the ash si al fe and na the source of ree in coals is mainly the suspended terrigenous material the specific enrichment of ree in the ash of low ash coals is a result of the interaction between the dissolved ree and the products of disintegration and decay of organic substances mainly the humic acids

mineralogical and geochemical compositions of the pennsylvanian coal in the adaohai mine daqingshan coalfield inner mongolia china modes of occurrence and origin of diaspore gorceixite and ammonian illite abstract aluminum hydroxide boehmite rich pennsylvanian coals of high volatile a bituminous rank were found previously in the jungar coalfield inner mongolia china this paper reports new results on 48 bench samples of the cp2 coal from the adjacent adaohai mine daqingshan coalfield inner mongolia and provides new insights into the origin and modes of occurrence of the minerals and elements present in the cp2 coal compared to the same coal in the adjacent mines the cp2 coal in the adaohai mine has a higher rank ro ran 1 58 which is attributed to igneous intrusions during the late jurassic and early cretaceous epochs the proportion of inertinite 35 3 in the coal is higher than that in other late paleozoic coals in northern china but lower than that in the jungar coals minerals in the cp2 coal include diaspore boehmite gorceixite calcite dolomite siderite clay minerals kaolinite and ammonian illite and trace amounts of anatase fluorapatite quartz and pyrite based on mineral proportions in the coal bench samples the cp2 coal may be divided into four zones i to iv from bottom to top the major mineral in zones i and iv is kaolinite zones ii and iii are mainly composed of ammonian illite diaspore boehmite gorceixite calcite dolomite and siderite diaspore boehmite and gorceixite forming materials were derived from oxidized bauxite in the weathered crust of the benxi formation in the sediment source region during peat accumulation however gorceixite may have formed earlier than diaspore the diaspore was derived from gibbsite that was subjected to dehydration by the heat of the igneous intrusions the ammonian illite may have been formed at a relatively high temperature by interaction of kaolinite with nitrogen released from the organic matter in the coal during metamorphism caused by the igneous intrusion the calcite and dolomite occur as epigenetic cell and fracture fillings and were probably derived from the igneous fluids compared to the common chinese and world coals the cp2 coal is enriched in cao 1 69 mgo 0 32 p2o5 0 214 f 207 g g ga 16 3 g g zr 446 g g ba 276 g g hg 0 33 g g and th 12 4 g g but has a lower sio2 al2o3 ratio due to the higher proportions of diaspore boehmite and gorceixite in the coal the f occurs mainly in gorceixite and fluorapatite the major carriers of ga are diaspore and kaolinite but not gorceixite barium mainly occurs in gorceixite and barite mercury was probably derived from the igneous intrusion and is distributed in both the organic matter and the minerals the elements are classified into five associations by cluster analysis groups a b c d and e group a represents a ree be y se ga ge sc in pb bi nb ta tio2 w hg sb zr hf th u association most of the elements in group a are lithophile elements that occur in aluminosilicate minerals group b sn te zn cd v as cr cu mo ni re is weakly correlated with ash yield and is associated with unidentified trace sulfide minerals elements in group c ad na2o al2o3 sio2 li k2o rb cs tl association probably occur in the clay minerals and diaspore group d consists of p2o5 ba f sr s and cl and with the exception of s they occur in minerals gorceixite and fluorapatite oxides of fe2o3 mno cao mgo make up group e and mainly occur in the carbonate minerals the coals are enriched in light rees and the lrees hrees have been highly fractionated with an average la yb n of 8 71 the heavy rees in the coals have a stronger organic affinity than the lrees

quantitative coal mineralogy of the sydney coalfield nova scotia canada by scanning electron microscopy computerized image analysis and energy dispersive x ray spectrometry automated image and x ray analysis with a scanning electron microscope has been used to fingerprint mineral particles in bituminous coals of the sydney coalfield and catalogue their chemical class and size distribution four seams hub harbour phalen and gardiner were analyzed quantitatively for some 32 000 mineral particles these analyses revealed particle size and weight distributions for 27 chemical classes manual searches augmented the computer automated scans covering eight seams and recording a total of 35 mineral species their paragenesis and sites for 28 elements sydney seam mineralogy is dominated by pyrite and kaolinite but illite chlorite siderite ankerite and quartz are locally prominent these are accompanied by a large variety of accessory minerals zircon rutile apatite barite gypsum rare earth phosphates and ore minerals and alteration products goethite and hydrated sulphates individual column benches show geochemical fades with different mineral suites resultin

coal deposits as potential alternative sources for lanthanides and yttrium abstract this paper presents data on widespread abnormal accumulations of lanthanides and yttrium rey in many coal deposits worldwide high rey contents 0 1 have been found in coal seams and coal ashes as well as in the host and basement rocks of some coal basins for a preliminary evaluation of coal ashes as an rey raw material not only the abundance but also the individual rey compositions were taken into account in this paper three rey distribution patterns for high rey coal ashes are fixed with lrey lan lun 1 mrey lan smn 1 and hrey lan lun

mineralogical and geochemical compositions of late permian coals and host rocks from the guxu coalfield sichuan province china with emphasis on enrichment of rare metals abstract this paper reports the geochemical and mineralogical compositions of the late permian no 25 coal semi anthracite and its host rocks roof and floor strata from the guxu gulin xuyong coalfield sichuan province china the coal is characterized by medium sulfur content average 2 73 and has an average ash yield of 20 95 in contrast to other late permian coals from southwestern china that are enriched in sc v cr co ni and cu the no 25 coal does not contain an abundance of these transition elements but is rich in lithophile elements be y nb zr hf and u the elevated concentrations of trace elements in the no 25 coal were probably derived from the felsic intermediate rocks at the top of the emeishan basalt sequence rather than from the emeishan mafic basalts the floor strata of the no 25 coal can be divided into two sub sections the upper sub section of the sequence immediately below the no 25 coal consists of material with a felsic intermediate composition probably derived from terrigenous sources and the lower sub section is composed of mafic tuff the terrigenous mineral matter in the no 25 coal appears to have the same sediment source region as the upper sub section of the floor strata based on their similar geochemical compositions the roof strata of the no 25 coal are more quartzose and were probably derived from a different sediment source region the mineral matter in the coal is dominated by kaolinite and to a lesser extent calcite and pyrite the roof and floor strata each have quite different mineralogy with kaolinite dominant in the latter and illite kaolinite and quartz in the former pyrite contents are variable both in the coal and in the host rocks the floor strata and the coal have been affected by hydrothermal solutions leading to the enrichment of rare earth elements and yttrium rey nb ta zr hf and u the rey in the coal and floor strata as well as the nb ta zr hf and u in the floor strata represent potentially economic rare metal resources

enrichment of u re v cr se and rare earth elements in the late permian coals of the moxinpo coalfield chongqing china genetic implications from geochemical and mineralogical data abstract rare metals in coal deposits have attracted much attention in recent years because of their potential economic significance this paper reports the abundance and enrichment origin of rare metals in the late permian coals k1 and k2 coals of the moxinpo coalfield chongqing southwestern china the k1 coal is characterized by highly elevated concentrations of u re v cr se and nb ta zr hf ree assemblages the latter assemblage is also enriched in the k2 coal the high temperature ash 815 c of the k1 coal is enriched in v cr se re u and ree the ash of the k2 coal and also the floor strata of each seam are enriched in ree potentially making all of the units economically viable sources for these elements the minerals in the k1 coal are mainly represented by kaolinite illite and mixed layer illite smectite and pyrite while the minerals in the k2 coal consist mainly of kaolinite and tobelite nh 4 k al 2 alsi 3 o 10 oh 2 authigenic roscoelite k v 3 al 2 alsi 3 o 10 oh 2 is commonly observed in the k1 coal under the sem and was probably formed by interaction of kaolinite with v derived from permeating u re v cr se rich solutions during early diagenesis the tobelite enriched in the k2 coal was formed by reaction between kaolinite already present in the coal and nh 4 derived from decomposition of the organic matter during hydrothermal alteration at a relatively high temperature the mafic tuffs directly underlying the k1 coal and containing limestone residual breccias not only served as the substrate for coal accumulation but also as the source of sediment from the uplifted areas around the coal basin the latter is indicated by low al 2 o 3 tio 2 ratios from 10 09 to 14 24 positive eu anomalies enrichment of medium rare earths relative to upper continental crust and detrital calcite of terrigenous origin the highly elevated concentrations of u re v cr se assemblages in the coal were derived from exfiltrational hydrothermal solutions and were then deposited in a euxinic environment the terrigenous materials in the k2 coal however were derived from felsic intermediate rocks at the top of the kangdian upland although the elevated concentrations of nb ta zr hf ree assemblages are attributed to the input of hydrothermal solutions

laminations from the palmer deep a diatom based interpretation 1 highly laminated holocene age diatomaceous sediments are characteristic of the palmer deep western antarctic peninsula ocean drilling program odp leg 178 site 1098 from 10 000 years b p to the present laminations are comprised of several groups of diatoms chaetoceros resting spores the dominant laminae former result from intense spring blooms rhizosolenia proboscia thalassiothrix and corethron are common also the consequence of summer production marked by a well stratified water column each lamination represents a single productivity event but laminations are not necessarily annual high concentrations of a subpolar form of eucampia antarctica in laminations between 9000 and 6700 years b p suggest early holocene warmth a consequence of southward intrusion of more subpolar waters the glacial interglacial transition is distinguished by pairs of laminae most likely deposited annually laminations with an overwhelming dominance of chaetoceros resting spores alternate with more terrigenous laminae representing alternation of intense spring blooms with more mixed deposition during the summer proximity to retreating glacial ice results in the supply of silt and sand that provides a marker bed between successive blooms

diatom distribution in southern ocean surface sediments atlantic sector implications for paleoenvironmental reconstructions abstract a study of 230 surface sediment samples collected in the atlantic sector of the southern ocean between the southernmost weddell sea and the subtropical zone documents the modern distribution of diatoms revealing patterns of paleoenvironmental significance estimations of diatom valves per gram dry sediment display numbers of 50 200 106 in the zone of high opal burial located between the mean position of the winter sea ice edge and the polar front and maximum values of greater than 200 106 in the near shore sedimentary basins off the antarctic peninsula lowest diatom concentrations and assemblages strongly affected by dissolution were encountered in the weddell basin despite alteration of the diatom assemblages prior to their incorporation into the sediment record the biogeographic distribution and the abundance pattern of most of the 35 studied diatom species shows a close relationship with the surface hydrography water temperature these relationships can be used to estimate past surface water temperatures based on statistical treatments of the assemblages or on simple relations of species occurrences in the geological record another close link occurs between the distribution of sea ice and sea ice related diatoms

mineralogical and geochemical compositions of the coal in the guanbanwusu mine inner mongolia china further evidence for the existence of an al ga and ree ore deposit in the jungar coalfield abstract aluminum hydroxide boehmite and diaspore ga rey rare earth elements and y and al rich pennsylvanian taiyuan formation coals have previously been found in the jungar and daqingshan coalfields inner mongolia china gallium rey and al are potentially extractable and usable elements in combustion residues derived from these coals this paper reports new results on 50 bench samples of the no 6 coal from the guanbanwusu mine jungar coalfield inner mongolia and provides new data and evidence for the existence of an al ga rey ore deposit in the unique jungar coalfield the no 6 coal in the guanbanwusu mine has a low rank ro ran 0 56 and a low sulfur content st d 0 58 the proportion of inertinite in the coal 56 7 mineral free basis is higher than that of vitrinite 31 the minerals in the coal are mainly represented by kaolinite boehmite and chlorite along with variable proportions in some samples of calcite ankerite siderite and goyazite boehmite goyazite and part of the kaolinite were derived from bauxite in the weathered surface of the sediment source region ankerite calcite and siderite in the coal are of authigenic origin the chlorite in the guanbanwusu coals appears to have a chemical composition intermediate between cookeite and chamosite this mineral mainly occurs as cell fillings also indicating an authigenic origin and was probably derived from hydrothermal fluids a new mineral phase mainly composed of ti cl and fe is probably a ti bearing oxychloride or hydroxychloride compared to other chinese coals and to world hard coals the coal from the guanbanwusu mine is enriched in al2o3 9 34 p2o5 0 126 li 175 g g f 434 g g cl 1542 g g ga 12 9 g g sr 703 g g and th 12 9 g g but has a lower sio2 al2o3 ratio 0 74 due to the higher proportions of boehmite and goyazite in the coal the major carrier of p2o5 and sr is goyazite lithium mainly occurs in the chlorite cf cookeite kaolinite and possibly to a lesser extent illite fluorine in the coal has a major boehmite affinity but a small proportion may also occur in the organic matter and chlorite gallium in the coal largely occurs in goyazite chlorine is independent of other elements in the coal associated neither with moisture nor with organic matter but possibly occurring in molecular form cl2 and in the ti bearing oxychloride or hydroxychloride thorium in the coal occurs in the clay and accessory minerals and was mainly derived from detrital materials of the source region rare earth elements and y have a mixed organic and inorganic affinity largely occurring in goyazite group minerals and to a lesser extent boehmite and organic matter most coal benches and partings have either an l type or h type of rey enrichment owing respectively to the weathered bauxite source region and groundwater effects the al2o3 ga rey and possibly li in the guanbanwusu coals like those in coals from the jungar and adjacent daqingshan coalfields are industrially useful metals that could potentially be recovered from the relevant coal combustion residues it is suggested that if ga in ash 50 g g rey 800 900 g g sio2 al2o3 40 in ash and coal thickness 5 m the coal combustion residues would be expected to be suitably enriched in al2o3 and can be considered for al2o3 ga and rey recovery

holocene climate evolution in the high latitude southern hemisphere simulated by a coupled atmosphere sea ice ocean vegetation model the holocene climate is simulated in a 9000 yr long transient experiment performed with the ecbilt clio vecode coupled atmosphere sea ice ocean vegetation model this experiment is forced with annually varying orbital parameters and atmospheric concentrations of co2 and ch4 the objective is to study the impact of these long term forcings on the surface temperature evolution during different seasons in the high latitude southern hemisphere we find in summer a thermal optimum in the mid holocene 6 3 ka bp with temperatures locally 3 degrees c above the preindustrial mean in autumn the temperatures experienced a long term increase particularly during the first few thousand years the opposite trend was simulated for winter and spring with a relatively warm southern ocean at 9 ka bp in inter up to 3 5 degrees c above the preindustrial mean and a warm continent in spring 3 degrees c followed by a gradual cooling towards the present these long term temperature trends can be explained by a combination of 1 a delayed response to orbital forcing with temperatures lagging insolation by i to months owing to the thermal inertia of the system and 2 the long memory of the southern ocean this long memory is related to the storage of the warm late winter spring anomaly below the shallower summer mixed layer until next winter sea ice plays an important role as an amplifying factor through the ice albedo and ice insulation feedbacks our experiments can help to improve our understanding of the holocene signal in proxies for instance the results suggest that in contrast to recent propositions teleconnections to the northern hemisphere appear not necessarily to explain the history of southern hemisphere temperature changes during the holocene

rare earth element bearing coals from the russian far east deposits abstract coal seams up to 10 m in thickness with high rare earth element ree concentrations 300 1000 ppm were detected in some of the russian far east deposits this paper reports on the ree composition of the coals from a number of deposits the ree bearing coals are subdivided into three geochemical types studies of ree distributions across the coal seams examination of gravitation fractions and sem edx studies have revealed that the enriched coals seams contain ree mainly as sorbed forms by organic matter and clay particles and fine grained authigenic minerals the ree coals formed in 1 erosion tectonic depressions with wide spread weathering crusts in their basins and 2 volcano tectonic grabens in which coal accumulation occurred simultaneously with bimodal volcanism in the former case ree are thought to originate from the borderland in the second case from chambers of subalkaline magma the ree accumulation in the organic material occurred mostly during the peat stage due to mineralized ree bearing water coming to the basins the high ree contents up to 1 0 and even more of the combustion wastes their low lree hree ratios and the considerable estimated resources all place the ree bearing coals of the russian far east among new and very promising mineral resources for y and heavy lanthanoids as by products

palaeoclimatic significance of late quaternary diatom assemblages from southern windmill islands east antarctica abstract the late quaternary palaeoenvironmental history of the southern windmill islands east antarctica has been reconstructed using diatom assemblages from two long well dated sediment cores taken in two marine bays the diatom assemblage of the lowest sediment layers suggests a warm climate with mostly open water conditions during the late pleistocene during the following glacial the windmill islands were covered by grounded ice preventing any in situ bioproductivity following deglaciation a sapropel with a well preserved diatom assemblage was deposited from 10 500 cal yr bp between 10 500 and 4000 cal yr bp total organic carbon corg and total diatom valve concentrations as well as the diatom species composition suggest relatively cool summer temperatures hydrological conditions in coastal bays were characterised by combined winter sea ice and open water conditions this extensive period of glacial retreat was followed by the holocene optimum 4000 to 1000 cal yr bp which occurred later in the southern windmill islands than in most other antarctic coastal regions diatom assemblages in this period suggest ice free conditions and meltwater stratified waters in the marine bays during summer which is also reflected in high proportions of freshwater diatoms in the sediments the diatom assemblage in the upper sediments of both cores indicates neoglacial cooling from 1000 cal yr bp which again led to seasonally persistent sea ice on the bays the holocene optimum and cooling trends in the windmill islands did not occur contemporaneously with other antarctic coastal regions showing that the here presented record reflects partly local environmental conditions rather than global climatic trends

sea ice seasonality during the holocene adelie land east antarctica abstract thin sections of laminated cores from different antarctic coastal areas have demonstrated the potential of diatom species to document climate change at the seasonal scale here we present the relative abundances of four diatom species and species groups fragilariopsis curta group as a proxy for yearly sea ice cover f kerguelensis as a proxy for summer sea surface temperature chaetoceros hyalochaete resting spores as a proxy for spring sea ice melting and the thalassiosira antarctica group as a proxy for autumn sea ice formation in core md03 2601 retrieved off adelie land on the antarctic continental shelf these abundances were compared to surface temperatures and sea ice cover modelled over the last 9000 years both the marine records and the simulated climate demonstrated a cooler early holocene 9000 7700 years bp a warmer mid holocene 7700 4000 years bp and a colder late holocene 4000 1000 years bp yearly sea ice cover followed an inverse pattern to temperatures with less sea ice during the mid holocene hypsithermal than during the late holocene neoglacial however diatom census counts and model output indicate that sea ice spring melting happened earlier in the season as expected but that autumn sea ice formation also occurred earlier in the season during the hypsithermal than during the colder neoglacial thereby following seasonal changes in local insolation

high and low latitude climate control on the position of the southern peru chile current during the holocene 1 we reconstructed changes of temperature salinity and productivity within the southern peru chile current during the last 8000 years from a high resolution sediment core recovered at 41 s using alkenones isotope ratios of planktic foraminifera biogenic opal and organic carbon paleotemperatures and paleosalinities reached maximum values at 5500 years ago and thereafter declined to modern values whereas paleoproductivity continuously increased throughout the last 8000 years we ascribe these long term holocene trends primarily to latitudinal shifts of the antarctic circumpolar current acc the concurrence with shifts in the position of the southern westerlies points to a common response of atmospheric and oceanographic circulation patterns off southern chile millennial to centennial scale fluctuations of paleotemperatures and paleosalinities on the other hand lag displacements in the position of the southern westerlies but reveal a significant correlation to short term temperature changes in antarctica indicating a high latitude control of the acc at these timescales

disposition of solar radiation in sea ice and the upper ocean a one dimensional sea ice model with an ice thickness distribution is presented to examine the disposition of the incoming surface shortwave radiation within the sea ice and the upper ocean the sea ice model consists of 15 different ice thickness categories and an open water leads category ice growth melting on horizontal and vertical surfaces meltwater pond growth and drainage and snow accumulation evolve independently for each of the ice categories leads melt ponds and thinner ice categories are of particular interest as these features account for nearly all of the solar energy that is transmitted into the upper ocean beneath the ice pack also examined is the surface reflection and absorption internal ice absorption and lateral melting for ponded and pond free ice area averaged results show that 69 of the total annual solar energy is reflected 15 is absorbed by the snow cover 12 is absorbed by the ice and 4 is transmitted to the ocean mixed layer through thin ice and leads

relationship between antarctic sea ice and southwest african climate during the late quaternary here we compare late quaternary southwest african climate records from the west coast of southern africa published winter rainfall and trade wind intensity records from a core off the coast of namibia to records of antarctic sea ice extent this comparison reveals coherent changes between antarctic sea ice extent and the southwest african winter rain region since 45 k y b p with enhanced winter rainfall and trade wind vigor during periods of increased sea ice presence we propose an oceanic and atmospheric coupling between antarctic sea ice and the winter rainfall zone of southwest africa that may lead to increased desertification in the region if global warming persists

aspects of the geochemistry of rare earth elements in coal an experimental approach abstract many coals worldwide are slightly enriched in heavy rare earth elements hree relative to light rare earth elements lree as compared with chondrites and shales a factor contributing to this fractionation could be the ability of the hree to form complexes with organic compounds which are more stable than those of the lree in order to test this hypothesis experiments on the sorption of several light and heavy rare earth elements la ce sm eu gd ho er lu on xylain and humic acids were performed the sorption on xylain was found to be ph and time dependent maximum quantity was sorbed in the range of ph 3 to 5 sorption equilibrium was reached in 5 to 7 days the shape of the sorption isotherms for all ree studied were similar the maximum content sorbed for each ree was about 0 2 meq 0 5 g xylain when all ree were present in equal concentration in the initial solution the quantity sorbed was also 0 2 meqv 0 5 g xylain nearly the same quantity of na k ca and mg were displaced from the sorbent these results suggest a cation exchange mechanism in which na k ca and mg bound to cooh and oh groups were replaced by the ree cations the capacity of humic acids leached from xylain was found to be about 0 05 meq ree on 0 250 mg humic acids ha the individual ree were sorbed in nearly equal quantities

modeling of antarctic sea ice in a general circulation model a dynamic thermodynamic sea ice model is developed and coupled with the melbourne university general circulation model to simulate the seasonal cycle of the antarctic sea ice distribution the model is efficient rapid to compute and useful for a range of climate studies the thermodynamic part of the sea ice model is similar to that developed by parkinson and washington the dynamics contain a simplified ice rheology that resists compression the thermodynamics is based on energy conservation at the top surface of the ice snow the ice water interface and the open water area to determine the ice formation accretion and ablation a lead parameterization is introduced with an effective partitioning scheme for freezing between and under the ice floes the dynamic calculation determines the motion of ice which is forced with the atmospheric wind taking account of ice resistance and rafting the simulated sea ice distribution compares reasonably well with observations the seasonal cycle of ice extent is well simulated in phase as well as in magnitude simulated sea ice thickness and concentration are also in good agreement with observations over most regions and serve to indicate the importance of advection and ocean drift in the determination of the sea ice distribution

the biogeography of major diatom taxa in southern ocean sediments 2 open ocean related species diatoms from 228 southern ocean core top sediment samples were examined to determine the geographic distributions of 32 major diatom species taxa preserved in the sediments of three zonally distinct regions sea ice open ocean and the tropical subtropical in the first of three papers 14 species taxa occurring in the region where sea ice covers the ocean surface on an annual basis are geographically documented comparisons are drawn between the diatom abundances on the sea floor sea ice parameters annual duration and concentration in february and september and february sea surface temperature such parameters are commonly used in reconstructing past oceanographic conditions in the sea ice and open ocean zones analysis of the geographic patterns and sea surface parameter correlations reveals species specific distributions regulated primarily by sea ice coverage and sea surface temperature which support the use of diatom remains for the estimation of these past seasurface environmental parameters comparison with reliable accounts of the 14 species from the sediments or plankton also provides the first glimpses into species specific ecology and habitat linkages d 2005 elsevier b v all rights reserved

geochemistry of rare earth elements in a marine influenced coal and its organic solvent extracts from the antaibao mining district shanxi china twenty six samples including roof bottom and coal plies of a marine influenced coal bed were collected from the antaibao mining district shanxi china the rare earth elements rees were determined in solids and organic solvent extracts the distribution pattern showed three distinct patterns shale like lree rich and hree rich this is attributed to the variable microenvironment of peat forming swamp the degree of marine influences and different ree sources rees in the coal are mainly controlled by detrital minerals but also affected by seawater the chondrite normalized ree patterns of the organic solvent extracts are distinctly different from those of corresponding original coal samples which show a negative eu anomaly a depletion of middle rees and an enrichment of hrees the lrees in coal extracts are likely adsorbed by hydrogen containing functional groups and hrees are likely bonded to carbon atoms

bioaccumulation record and paleoclimatic significance in the western bransfield strait the last 2000 years abstract two gravity cores a 3 and a 6 from the western basin of the bransfield strait antarctica were recovered during the bio hesperides expedition fruela 96 both cores consist mainly of hemipelagic and laminated muds with black layers rich in sand sized volcanic ash geochemical analyses toc and opal radiometric dating techniques ams 14 c and 210 pb and micropaleontological analyses diatoms were performed on both cores ams analyses on toc yielded 14 c ages older than expected 3960 50 yr bp for the core top of a 3 and 3410 50 yr bp for a 6 210 pb analyses revealed that core top age for both gravity cores could be estimated to be about 100 15 yr bp the results of diatom analyses were related to the sequence of neoglacial events that have occurred over the last two millennia the abundance patterns of chaetoceros rs the biogenic silica content and the abundance of diatom valves agree with the high productivity values previously reported for the bransfield strait waters the significant recent reduction in resting spores of the diatom chaetoceros suggests as a reduction in surface productivity trend differences between chaetoceros resting spore abundance and toc contents are explained in terms of organic matter preservation diatom communities from the bransfield strait did not play an important role in the global co 2 cycle during cold periods bio and geochemical changes have an overprinted high frequency cyclicity at about 200 300 yr which might be related to the 200 yr solar cycle

seismo stratigraphic analysis of the wilkes land continental margin east antarctica influence of glacially driven processes on the cenozoic deposition abstract multichannel seismic reflection data were collected from the wilkes land continental margin and particularly focusing on the lower rise area by the international wilkes basin glacial history wega project existing lower resolution seismic data also are used to understand the relationship between the basement and the sedimentary cover and to correlate the evolution of the rise and the shelf on the basis of the acoustic character and the internal geometry we recognise nine different sequences named wl s1 wl s9 from the deepest to the shallowest within the sedimentary section sequence wl s1 represents syn rift sediments deposited within tilted blocks of sedimentary crystalline and volcanic basement sequences wl s2 wl s9 represent the post rift sediments that show quite a complex architecture sequence wl s2 is a well developed wedge downlapping onto the break up unconformity sequences wl s3 wl s7 are parts of a margin prograding aggrading sequence during which large sediment ridges were deposited on the slope and rise in particular sequences wl s5 wl s7 began with the deposition of a turbidite fan system sequence wl s5 that developed in a braided channel levee complex wl s6 wl s7 dominated by downslope flows indirect correlation of the sequences wl s4 wl s6 with dsdp 269 about 600 km north of the study area suggests an early late miocene age sequences wl s8 and wl s9 represent the smoothing and filling of the pre existing morphology in a generally low energy environment with reduced bottom current activity during this time most of the sediment is deposited on the shelf and slope while the rise is generally starved differences in downslope current energy and in sediment load are interpreted to reflect variation of the terrigenous input from the shelf to the rise through time we suggest that channel levee systems on the rise reflect an increase in sediment supply from the continental shelf during the early miocene marking the growth of wet based temperate ice sheet on the near continent the youngest sequences on the rise and shelf reflect decreased sediment supply to the rise that may be related to the transition from a temperate to a polar glacial system

quantification of the modes of occurrence of 42 elements in coal abstract a series of 20 coal samples were subjected to sequential leaching with ammonium acetate hydrochloric acid hydrofluoric acid and nitric acid to quantify the modes of occurrence of about 42 elements the results indicate that within a coal rank the leaching behavior of many elements are broadly similar however the behavior of many elements varies between bituminous and subbituminous coals while the leaching behavior of most elements is consistent with previous mode of occurrence interpretations there were a number of unanticipated results about 75 of the arsenic in bituminous coals appears to be associated with sulfides probably pyrite however only 40 of the arsenic in the low rank coals appears to be associated with pyrite in the bituminous coals we interpret that about 60 of the beryllium is associated with silicates but in the low rank coals only 30 is silicate associated in the bituminous coals 25 of the magnesium is associated with carbonates but in the low rank coals 75 of the magnesium is in the carbonates fifty five percent of the molybdenum was associated with the sulfides in the bituminous coals and in the low rank coals 65 was in the silicates in the bituminous coals the rare earth elements ree are predominantly in the phosphate minerals 70 for the light ree and 50 for the heavy ree but in the low rank coals the ree 50 60 are associated with the clays sodium is predominantly 80 associated with silicates in the bituminous coals and with the organics 65 in the low rank coals titanium appears to occur more in the clays 65 bituminous 70 low rank than in oxides 35 bituminous 15 low rank tungsten is in the sulfides 50 in the bituminous coals but in the clays 60 in the low rank coals uranium is associated with the silicates 40 and insoluble phases such as zircon 30 in the bituminous coals but is associated with the organics 55 in the low rank coals many of these rank differences reflect a higher detrital input and greater sulfide mineralization of the bituminous coals

southern ocean sea ice control of the glacial north atlantic thermohaline circulation 1 a coupled model simulates a shallower and weaker north atlantic deep water circulation at the last glacial maximum compared to the modern with an enhanced intrusion of antarctic bottom water into the north atlantic these circulation changes are caused by the enhanced antarctic bottom water formation which is triggered by the enhanced equatorward sea ice transport ultimately by increased westerlies in the southern ocean at the last glacial maximum

a 13 200 year history of century to millennial scale paleoenvironmental change magnetically recorded in the palmer deep western antarctic peninsula abstract a 13 200 yr record of magnetic parameters from the palmer deep western antarctic peninsula records a sequence of five distinct shifts in glacimarine sedimentation coupled with century scale variations in paleoproductivity the five major shifts are manifested as abrupt order of magnitude changes in low field magnetic susceptibility accompanied by changes in magnetic particle size and mineralogy the late holocene 3 4 0 ka the early holocene 11 5 9 ka and the last glacial maximum prior to 13 2 ka are intervals of strong low field magnetic susceptibility and are characterized by multi domain md magnetite md magnetite is associated with zones of abundant gravel grains and is interpreted here as an indicator of material transported as ice rafted debris deglaciation 13 2 11 5 ka and the middle holocene 9 3 4 ka were times of enhanced productivity the middle holocene marks the onset of century scale productivity cycles seen in high field magnetic susceptibility which is responding to variations in biogenic silica deglaciation and the middle holocene interval contain pseudo single domain magnetite and titanomagnetite respectively these observations are surprising given the abundance of coarse md magnetite available in local source rocks the magnetic mineral assemblage in the deglaciation interval however can be explained by density sorting in meltwater plumes during the middle holocene the magnetic mineral assemblage suggests the reduction or cessation of locally derived terrigenous sediment and by inference the reduction or cessation of iceberg generation the early holocene middle holocene shift in terrigenous sedimentation may be responding in part to sea level which controls the position of the grounding line the palmer deep late holocene interval coincides with the neoglacial period a time of glacier re advances worldwide

application of modern analog technique to marine antarctic diatoms reconstruction of maximum sea ice extent at the last glacial maximum modern analog technique mat applied to antarctic diatoms is a new approach for quantitative sea ice paleoreconstructions in the southern ocean in a first step we show that mat is a better approach than the imbrie and kipp method to reconstruct the modern sea ice pattern we then use this approach to reconstruct sea ice presence in number of months per year during the last glacial maximum lgm at this time sea ice presence was greater than today leading to a shorter diatom growing season the maximum sea ice extent inferred from quantitative values of sea ice presence was located 5 8 north of its actual position leading to double the surface of modern winter sea ice this greater sea ice extent may have played a significant role on atmospheric and surface oceanic circulations and therefore on southern mid latitude and high latitude climates it may also have reduced the amount of heat moisture and co2 from the ocean to the atmosphere thus participating in the lowering of atmospheric co2 during the lgm

phytoplankton biomass and photosynthetic competency in the summertime mertz glacier region of east antarctica abstract vertical profiles of water temperature salinity beam transmission density pressure wind speed wind direction phytoplankton biomass chlorophyll a chl a plus phaeophytin a and photosynthetic competency by fast repetition rate fluorometry are presented for the mertz glacier region east antarctica for a 3 week period during the austral summer 2000 2001 injection of low salinity water from the melting of the ice pack formed a shallow ca 25 m mixed layer offshore two distinct deep mixing features were observed associated to varying degrees with high chlorophyll levels and high photosynthetic competency along the adelie land coast a deep mixing layer 1400 m with chl a concentrations of 386 mg m 2 and elevated fv fm 0 5 was observed at the eastern end of the study area along a seaward extension of fast ice a bloom of phaeocystis antarctica bloom formed within a shallow 24 m mixed layer with surface chl a concentrations of ca 8 mg m 3 and elevated fv fm 0 5 this feature also had high surface salinity 34 and was contiguous with a deep mixing feature 236 m frrf parameters fv fm and psii were strongly suppressed in surface waters

a review of anomalous rare earth elements and yttrium in coal abstract coal deposits have attracted much attention in recent years as promising alternative raw sources for rare earth elements and yttrium rey not only because the rey concentrations in many coals or coal ashes are equal to or higher than those found in conventional types of rey ores but also because of the world wide demand for rey in recent years has been greater than supply in addition to anomalies of enrichment or depletion of light medium and heavy rey in coal deposits normalized to upper continental crust post archean australian shale or north american shale composite anomalies of redox sensitive ce and eu and in some cases of non redox sensitive la gd and y could be used as geochemical indicators of the sediment source region sedimentary environment tectonic evolution and post depositional history of coal deposits factors controlling rey anomalies in coal deposits include the geochemistry of terrigenous source rocks ingress of hydrothermal fluids influence of marine environments percolating natural waters volcanic ashes and sedimentary environments of peat formation additionally the smoothness of a normalized rey distribution pattern provides a simple but reliable basis for testing the quality of rey chemical analyses for coal and other sedimentary rocks

geomorphology and dynamics of a traveling cuspate foreland authie estuary france abstract cuspate forelands or salients occur all over the world in lakes estuaries and on ocean shores yet there have been few studies conducted on traveling cuspate forelands or salients that is forelands that migrate or travel alongshore this paper presents a study of a traveling foreland in the authie estuary france termed the bec du perroquet historical shoreline changes may be traced from the 1200 s ad and the region has experienced both marked intertidal subtidal accretion extending from the south and massive erosion in the north since this period an analysis of aerial photographs from 1947 until the present shows that the original bec foreland was established at the mouth of the authie estuary but gradually disappeared by the 1960 s and a new foreland developed in the middle of the northern central portion of the bay this foreland was composed of a suite of foredune ridges which have been successively eroded on the northern margin and initiated on the southern margin as the foreland traveled or migrated southwards as the foreland traveled south from 1947 to 2009 the northern part of the bay retreated more than 350 m while mid bay the coastline retreated 215 m as the foreland evolves and migrates incipient foredunes can develop rapidly e g 18 ridges formed in an 11 week period while at other times the ridges form slowly and may be eroded and disappear two or more foredune ridges may blend into a single ridge over time depending on the initial degree of vegetation cover on the ridge and swale set aeolian processes in dune swales are much more important in this system than in typical prograding foredune plain systems due to the sometimes marked lack of vegetation colonization in the swales following foredune ridge development and aeolian deflation of the swales along with blowout development is important particularly when they become open conduits to the beach as erosion of the nw foreland proceeds the ages of each of the surviving ridges on the foreland in 2009 have been determined and the evolutionary path of the ridges ascertained formerly intact relatively stable continuous ridges evolve to erosional knobs turrets and nebkha over time foredune ridges and swales can be extremely arcuate to semi circular in form where the foreland and especially the spit extension are exposed to a wide range of wind directions and where the shoreline trends through an arc of at least 270 this study illustrates a remarkable cycling of the formation destruction and reformation travel of a cuspate foreland over a 50 year period

holocene climate variability in antarctica based on 11 ice core isotopic records a comparison is made of the holocene records obtained from water isotope measurements along 11 ice cores from coastal and central sites in east antarctica vostok dome b plateau remote komsomolskaia dome c taylor dome dominion range d47 km105 and law dome and west antarctica byrd with temporal resolution from 20 to 50 yr the long term trends possibly reflect local ice sheet elevation fluctuations superimposed on common climatic fluctuations all the records confirm the widespread antarctic early holocene optimum between 11 500 and 9000 yr in the ross sea sector a secondary optimum is identified between 7000 and 5000 yr whereas all eastern antarctic sites show a late optimum between 6000 and 3000 yr superimposed on the long time trend all the records exhibit 9 aperiodic millennial scale oscillations climatic optima show a reduced pacing between warm events typically 800 yr whereas cooler periods are associated with less frequent warm events pacing 1200 yr

notes on southern ocean hydrography sea ice and bottom water formation abstract the southern ocean circulation and sea ice distribution is briefly described the formation of extremely cold bottom water in the weddell sea and its relation to the floating ronne filchner ice shelves is discussed it is shown that a concentrated swift eroding bottom current with anomalous low 18 o ratio transports the cold and dense ice shelf water from the shelf towards large depths comments are made on possible implications of this process for the large scale deep water circulation and for the interpretation of sediment cores

post glacial seasonal diatom record of the mertz glacier polynya east antarctica an ultra high resolution post glacial laminated sediment record from mertz ninnis trough east antarctic margin eam has been analysed using sem backscattered electron imagery secondary electron imagery and quantitative diatom abundance laminations are classified using visually dominant diatom species and terrigenous content four biogenic diatom ooze laminae types one diatom bearing terrigenous lamina type and one diatom bearing terrigenous sub lamina type have been identified diatom ooze lamina types comprise near monogeneric hyalochaete chaetoceros spp resting spore laminae laminae characterised by corethron pennatum laminae characterised by rhizosolenia spp and mixed diatom assemblage laminae diatom bearing terrigenous lamina and sub lamina types comprise mixed diatom assemblage terrigenous laminae and sub laminae characterised by porosira glacialis resting spores formation of each of these lamina types is controlled by seasonal changes in nutrients oceanographic regimes and the mertz glacier polynya dynamics

the reconstruction of late quaternary antarctic sea ice distribution the use of diatoms as a proxy for sea ice the study of annual diatom transfer from the southern ocean surface to the sea floor using time series sediment traps combined with the mapping of diatom assemblages from surface sediments results in the definition of a proxy for past variations of sea ice extent the application and robustness of the proposed proxy are demonstrated by the study of late pleistocene sediment cores recovered from different environmental regimes in the southern ocean relative amounts of the sea ice indicator diatoms fragilariopsis cylindrus and fragilariopsis curta of 3 in diatom assemblages preserved in sediments are representative of the presence of seasonal winter sea ice summer sea ice occurrence is signalled by a distinct drop in biogenic sedimentation rate as a result of strongly reduced biogenic export in the presence 3 of diatom assemblage of the deep temperature diatom fragilariopsis obliquecostata the spatial and temporal distribution pattern of the sea ice proxy indicates significant sea ice variations during marine isotope stages 1 and 5 in the present antarctic zone of the southern ocean during glacial maxima the antarctic winter sea ice was extended into the present polar front zone while the antarctic summer sea ice was most probably expanded into the area of the present winter sea ice edge during the short climatic optima at the onset of interglacial periods the winter sea ice extent was distinctly reduced

occurrence modes and cleaning potential of sulfur and some trace elements in a high sulfur coal from pu an coalfield sw guizhou china in this research a float sink test was applied to a late permian high sulfur coal collected from pu an coalfield southwest in guizhou china to investigate the occurrence modes and the mobility of various trace elements as well as the cleaning potential of some harmful elements in density separation coal quality parameters and concentrations of 46 elements of 7 density fractionated samples were determined and statistically analyzed results show that larger size and higher density fractions have higher total sulfur content and ash yield than the smaller and lower ones in fact most 74 39 of the total sulfur occurs in the inorganic matter affinity and correlation analysis show that mo and ni have apparently strong organic affinity whereas rh cs sr co nb zr v ga sc be ge hf th u ag as in cu cd ta li ti and ba are mostly in the heavy fractions rare earth element ree patterns for the seven density fractions present good uniformity and show that they are of right inclined pattern type characterized by light ree lree la eu enrichment relative to heavy ree hree gd lu and pronounced negative eu anomalies this suggests that ree was mainly derived from basalt weathered materials lrree hree ratio variations reveal that lree has stronger affinity with the organic matter relative to the hree while high lrree hree in heavy fractions may be related to pyrite supposing the maximum sulfur content of the cleaned coal is 1 00 the theoretical removal ratios of co ti and ba are as high as 90 94 93 73 and 92 29 respectively while those of as ni and mo are only 56 33 48 85 and 45 05 respectively as these figures change with different maximum sulfur contents required for the cleaned coal not only the decrease of sulfur and ash in coal washing but also the mobility of some harmful trace elements should be taken into consideration

microfossil and stable isotope evidence for changes in late holocene palaeoproductivity and palaeoceanographic conditions in the prydz bay region of antarctica microfaunal and microfloral data from two gravity cores and stable isotope results from one of these cores taken on fram bank near prydz bay antarctica indicate changes in sea ice patterns and oceanographic conditions which may have been linked to regional and global climate changes that occurred over the past 8000 yr modern diatom assemblages indicative of ice free conditions 1 2 months of the year and dominated by nitzschia species became prevalent some time around 2000 2700 yr b p the occurrence of chaetoceros spp diatom spore dominated assemblages and increased abundances of benthic and planktonic foraminifera ostracods and diatoms coupled with carbon and oxygen isotope changes around 2700 3400 yr b p strongly suggests that this area of the shelf experienced conditions conducive to increased productivity during this time period based on diatom assemblage associations recognized in modern environments the upper water column of fram bank shelf waters was probably stratified during that time due to the presence of low salinity melt water and a very shallow mixed layer protected from storms with sea ice cover for less than 10 months per year the close correspondence of 13c and 18o values from n pachyderma r2 0 74 throughout one core suggests that whatever oceanographic conditions influenced 18o also influenced 13c changes in prydz bay microfossil abundances and isotopes may result from alterations in circulation patterns upwelling conditions or sea ice patterns which significantly affected benthic and planktonic productivity in the area the environmental conditions indicated by older sediments in the cores are less clear but an ice tongue may have been in place 3200 3800 yr b p and minor fluctuations in productivity are indicated around 6000 and 7000 7500 yr b p the lower 100 cm of both cores may not represent in situ deposition but if the corrected ams dates reflect the actual age of the sediments analyzed microfossil and isotope data indicate that productivity and oceanographic conditions were very variable around 8500 8600 yr b p the chronology adopted herein must be regarded as tentative until further study of the area has been undertaken

mineralogy and geochemistry of boehmite rich coals new insights from the haerwusu surface mine jungar coalfield inner mongolia china abstract boehmite rich coal of pennsylvanian age was discovered earlier at the heidaigou surface mine jungar coalfield inner mongolia china this paper reports new results on 29 bench samples of the no 6 coal from a drill core from the adjacent haerwusu surface mine and provides new insights into the origin of the minerals and elements present the results show that the proportion of inertinite in the no 6 coal is higher than in other late paleozoic coals in northern china based on mineral proportions boehmite to kaolinite ratio and major element concentrations in the coal benches of the drill core the no 6 coal may be divided into five sections i to v major minerals in sections i and v are kaolinite sections ii and iv are mainly kaolinite with a trace of boehmite and section iii is high in boehmite the boehmite is derived from bauxite in the weathered surface benxi formation in the sediment source region the no 6 coal is rich in al2o3 8 89 tio2 0 47 li 116 g g f 286 g g ga 18 g g se 6 1 g g sr 350 g g zr 268 g g rees 172 g g pb 30 g g and th 17 g g the elements are classified into five associations by cluster analysis i e groups a b c d and e group a ash sio2 al2o3 na2o li and group b ree sc in y k2o rb zr hf cs u p2o5 sr ba ge are strongly correlated with ash yield and mainly have an inorganic affinity the elements that are negatively or less strongly correlated with ash yield with exceptions of fe2o3 be v and ni are grouped in the remaining three associations group c se pb hg th tio2 bi nb ta cd sn group d co mo tl be ni sb mgo re ga w zn v cr f cu and group e s as cao mno fe2o3 aluminum is mainly distributed in boehmite followed by kaolinite the high correlation coefficients of the li ash li al2o3 and li sio2 pairs indicate that li is related to the aluminosilicates in the coal the boehmite rich coal is high in gallium and f which occur in boehmite and the organic matter selenium and pb are mainly in epigenetic clausthalite fillings in fractures the abundant rare earth elements in the coal benches were supplied from two sources the bauxite on the weathered surface of the benxi formation and from adjacent partings by groundwater leaching during diagenesis the light rare earth elements lrees are more easily leached from the partings and incorporated into the organic matter than the heavy rees leading to a higher ratio of lrees to hrees in the coal benches than in the overlying partings