hydrocarbon potential and depositional environments of oligo miocene rocks in the eastern carpathians vrancea nappe romania abstract the oligocene to early miocene fine grained succession in the eastern carpathians includes from base to top the lower menilite lmm bituminous marl bmm lower dysodilic shale ldsm and upper dysodilic shale udsm members these stratigraphic units constituting the main hydrocarbon source rocks in the eastern carpathians have been studied in an outcrop section to determine its depositional environment and hydrocarbon potential the lmm contains high amounts of toc but because of low thickness its source potential is limited the organic matter of the overlying bmm is mainly derived from autochthonous marine organisms including bacterial biomass toc contents are moderate because of dilution by carbonate minerals calcareous nannoplankton dates the bmm into nannoplankton zones np21 22 salinity and redox conditions varied from reduced to slightly enhanced and from strictly anoxic to dysoxic the ldsm contains carbonate free black shale and sandstone beds deposited in a depositional lobe under anoxic conditions despite of high hi values land plants form a significant part of the organic matter channel fill sediments form the top of the ldsm the lower part of the early miocene udsm accumulated in a lobe whereas its upper part represents a basin plain setting mttc ratios reflect a trend from slightly enhanced to slightly decreased normal marine salinity the presence of aryl isoprenoids suggests a temporary photic zone anoxia controlled by salinity variations both marine and terrestrial biomass contributed to the organic matter a major change towards oxic conditions occurred at the boundary between the udsm and the overlying gura soimului formation the studied succession can generate 6 t of hydrocarbons per square meter all members are oil prone but yield oil with different biomarker characteristics this allows the identification of oil generated from different lithostratigraphic units

organic matter in oligocene menilite formation rocks of the ukrainian carpathians palaeoenvironment and geochemical evolution abstract the ukrainian carpathians form the middle sector of the carpathian arc the menilite black shale formation oligocene early miocene is the youngest part of the flysch sequence and occurs in a wide depth range the anaerobic bacterial processes during early diagenesis led to formation of 13 c rich carbonate concretions and 13 c depleted organic matter black shales contain type ii kerogen with high source rock potential in the upper 4 km of the sequence the rocks preserved their pre overthrusting level of maturity close to the beginning of the oil window while at greater depths the maturity increases under the influence of present day heat flow

stratigraphic and geochemical study of the organic rich black shales in the tarcău nappe of the moldavidian domain carpathian chain romania an integrated stratigraphic analysis has been made of the tarc u nappe moldavidian domain eastern romanian carpathians coupled with a geochemical study of organic rich beds two main sequence boundaries early oligocene and near to the oligocene aquitanian boundary respectively divide the sedimentary record into three depositional sequences the sedimentation occurred in the central area of a basin supplied by different and opposite sources the high amount of siliciclastics at the beginning of the miocene marks the activation of the foredeep stage the successions studied are younger than previously thought and they more accurately date the deformation of the different miocene phases affecting the moldavidian basin the intervals with black shales identified are related to two main separate anoxic episodes with an age not older than late rupelian and not before late chattian the most important organic rich beds correspond to the lower menilites bituminous marls and lower dysodilic shales members interval 2 these constitute a good potential source rock for petroleum with homogeneous type ii oil prone organic matter highly lipidic and thermally immature the deposition of black shales has been interpreted as occurring within a deep periodically isolated and tectonically controlled basin

oil oil and oil source rock correlations in the carpathian foredeep and overthrust south east poland abstract the chemical composition of 35 crude oils and the extracts of potential source rock samples from south east poland were studied in detail by geochemical methods in order to understand their genetic relationships twenty six oils including three seep samples were collected from cretaceous to oligocene reservoirs within the carpathian overthrust nine oils originated from carboniferous to miocene reservoirs within the carpathian foredeep the rock samples studied were selected after rock eval pyrolysis screening of a large suite of samples and consist of one lower cretaceous sample and five oligocene menilite shale samples from three different outcrop locations all within the carpathian overthrust geochemical fingerprinting indicates at least two families of crude oils the first represented only by one oil has no specific characteristics except for a light carbon isotope composition the second family is characterized by the presence of 28 30 dinor hopane oleanane and a highly branched isoprenoid c25 alkane within this latter family four subfamilies were recognized a 19 oils having the aforementioned characteristics b seven oils similar to subfamily a but with a relatively high sulphur content c one oil with high abundance of higher plant derived triterpanes and d seven oils with abundant 28 30 dinor hopane although maturity influences the relative abundance of 28 30 dinor hopane it suggested that subfamilies a b and c had an initial low 28 30 dinor hopane content whereas subfamily d an initial high 28 30 dinor hopane content only one oil of subfamily a could potentially be a high maturity counterpart of subfamily d a palaeozoic source rock is suggested for the first family and the second family including the majority of the pils from the carpathian foredeep is most likely derived from the oligocene menilite shales an oil source rock relationship with the menilite shale is supported by the presence although not in all samples studied of 28 30 dinor hopane oleanane or its precursors and the highly branched isoprenoid alkane the strong facies variations observed within this shale gave rise to the different types of crude oils in the second family

diagenetic and catagenetic products of isorenieratene molecular indicators for photic zone anoxia a wide range of novel diagenetic and catagenetic products of the diaromatic carotenoid isorenieratene a pigment of the photosynthetic green sulphur bacteria chlorobiaceae has been identified in a number of sedimentary rocks ranging from ordovician to miocene compound identification is based on nmr mass spectrometry the presence of atropisomers and stable carbon isotopes atropisomers contain an axially chiral centre which in combination with other chiral centres results in two or more diastereomers that can be separated on a normal gc column chlorobiaceae use the reverse tca cycle to fix carbon so that their biomass is enriched in 13c high 13c contents of isorenieratene derivatives therefore support their inferred origins isorenieratene derivatives include c 40 c 33 and c 32 diaryl isoprenoids and short chain aryl isoprenoids with additional aromatic and or s containing rings c 33 and c 32 compounds are diagenetic products of c 33 and c 32 carotenoids formed from isorenieratene during early diagenesis through expulsion of toluene and m xylene respectively cyclisation of the polyene acyclic isoprenoid chain can proceed via an intramolecular diels alder reaction followed by aromatisation of the newly formed ring sulphurisation is also an important process during early diagenesis competing with expulsion and cyclisation sulphur bound isorenieratane is released during progressive diagenesis due to cleavage of relatively weak ss and cs bonds cleavage of c c bonds during aromatisation of newly formed rings and during catagenesis yields short chain compounds the inherent presence of a conjugated double bond system in carotenoids implies that similar diagenetic and catagenetic reactions can occur with all carotenoids chlorobiaceae live at or below the oxic anoxic boundary layer and require both light and h 2s the presence of isorenieratene or its diagenetic and catagenetic products in ancient sedimentary rocks and crude oils is therefore an excellent indication for photic zone anoxia in the depositional environment diagenetic and catagenetic products of isorenieratene are expected to find applications in reconstruction of palaeoenvironments and in oil oil and oil source rock correlation studies their presence in several petroleum source rocks suggests that anoxia is an important environmental parameter for the preservation of organic matter

a new approach to interpreting rock eval s2 and toc data for kerogen quality assessment abstract a simple method for application in source potential mapping is used to assess the original oil and gas potentials in source rock horizons based upon rock eval potential s 2 and total organic carbon toc values the method assumes that kerogens consist of mixtures of end members with assigned hydrogen index values based on suggested algorithms the average amounts of oil prone gas prone and inert organic material over source rock intervals are determined in toc units the method uses regression lines from plots of remaining hydrocarbon potentials s 2 versus total organic carbon toc and quick look transparent overlays are used to read the appropriate kerogen mixture mineral matrix effects during pyrolysis when strong can cause erroneous results this effect which occurs for oil prone kerogens and adsorptive minerals can cause problems particularly for lean samples s 2 0 3 mg hc g rock whilst the errors for richer samples are less the method is applied on three sections of upper jurassic organic rich rocks from the danish north sea sector which are at different maturity stages one of these sections is dominated by gas prone material one is dominated by oil prone material and the third section contains a mixture of oil and gas prone material the method has been compared with other methods that split kerogens in oil and gas generating potential and has given reasonable results experience using the method and a presented example suggest that sedimentological system tract information may be derived from s 2 to toc cross plots a constructed modelling example suggests that the end member concept used in this approach may be used in forward type source rock prediction models when combined with sedimentological models the resulting s 2 toc plots can be used in order to check the forward modelling results against observed values

an 11 year record of mass balance of brewster glacier new zealand determined using a geostatistical approach recognising the scarcity of glacier mass balance data in the southern hemisphere a mass balance measurement programme was started at brewster glacier in the southern alps of new zealand in 2004 evolution of the measurement regime over the 11 years of data recorded means there are differences in the spatial density of data obtained to ensure the temporal integrity of the dataset a new geostatistical approach is developed to calculate mass balance spatial co variance between elevation and snow depth allows a digital elevation model to be used in a co kriging approach to develop a snow depth index sdi by capturing the observed spatial variability in snow depth the sdi is a more reliable predictor than elevation and is used to adjust each year of measurements consistently despite variability in sampling spatial density the sdi also resolves the spatial structure of summer balance better than elevation co kriging is used again to spatially interpolate a derived mean summer balance index using sdi as a co variate which yields a spatial predictor for summer balance the average glacier wide surface winter summer and annual balances over the period 2005 15 are 2484 2586 and 102 mm w e respectively with changes in summer balance explaining most of the variability in annual balance

investigation of late holocene moraines in the western southern alps new zealand applying schmidt hammer exposure age dating chronological studies applying schmidt hammer exposure age dating shd were performed on six glacier forelands in the western part of the southern alps new zealand although lithological heterogeneity prevented a regional age calibration curve to be established local age calibration curves for la perouse glacier and strauchon glacier could be derived they show similar linear equations and trends slopes and enabled a preliminary assessment of the representativeness of individual 10be terrestrial cosmogenic nuclide dating tcnd ages obtained from the other forelands no mid and early holocene advance periods were detected clusters of moraine ages date around 2800 1850 1450 and 1100 900 years ago followed by the little ice age commencing c 500 years ago there is no good agreement with earlier radiocarbon based studies and recently published tcnd chronologies as it will be outlined this partly could be the result of different approaches to the palaeoclimatic interpretation of the dated samples

relationships between synoptic scale atmospheric circulation and glacier mass balance in south western canada during the international hydrological decade 1965 74 on recherche la correlation entre la circulation atmospherique a l echelle synoptique et le bilan glaciaire dans la cordillere du sud ouest canada des techniques de caracterisation synoptiques objectives sont appliquees a des donnees glacio meteorologiques provenant du peyto glacier en alberta et sentinel glacier en colombie britannique et a des releves climatologiques emanant des stations meteorologiques voisines au niveau de 500 mbar on a analyse et compare deux echelles de cartes meteorologiques synoptiques l une est plus petite avec de nombreuses fluctuations l autre est plus grande avec des traits plus generaux

source rock habitat and hydrocarbon potential of oligocene menilite formation flysch carpathians southeast poland an organic geochemical and isotope approach geochemical and isotope methods have been used to analyse the hydrocarbon potential and petroleum generation characteristics of the oligocene menilite formation the most important petroleum source rock in the overthrust part of the carpathian foreland basin in se poland the data show a large variability in quantity up to 18 toc quality type ii and ii iii and carbon isotope composition of the organic matter in samples of different lithology and from different stratigraphic and tectonic settings these differences reflect distinct sedimentary and tectonic histories of individual sub basins the maturity in the outer tectonic units is very low tmax 420 c ro 0 35 but increases towards the inner nappes and also laterally to the se the variability of the kinetic parameters indicates the likely occurrence of multiphase hydrocarbon generation the menilite formation forms a very good source rock in the complex petroleum system of the carpathian overthrust belt

behaviour of new zealand glaciers and atmospheric circulation changes over the past 130 years there is renewed interest as to the impact of future climate change on temperate alpine glaciers because of their role as indicators of past and ongoing changes and due to their possible involvement in sea level rise substantial changes in termini of new zealand glaciers since the nineteenth century are compared with variations in atmospheric circulation patterns over the southwest pacific region reconstructed sea level pressure patterns are used back to 1911 atmospheric circulation indices obtained from pressure differences between appropriate stations are extended back to the 1860s circulation anomalies are examined for winter related to glacier accumulation and for summer related to glacier ablation behaviour of glacier termini is found to be strongly linked with circulation changes especially in summer latitudinal shifts in the southern margin of the subtropical high pressure zone are identified as important an advance of some glaciers since 1980 is consistent with circulation changes over the new zealand region induced by two large el nino events

the little ice age climate of new zealand reconstructed from southern alps cirque glaciers a synoptic type approach little ice age lia austral summer temperature anomalies were derived from palaeoequilibrium line altitudes at 22 cirque glacier sites across the southern alps of new zealand modern analog seasons with temperature anomalies akin to the lia reconstructions were selected and then applied in a sampling of high resolution gridded new zealand climate data and global reanalysis data to generate lia climate composites at local regional and hemispheric scales the composite anomaly patterns assist in improving our understanding of atmospheric circulation contributions to the lia climate state allow an interrogation of synoptic type frequency changes for the lia relative to present and provide a hemispheric context of the past conditions in new zealand an lia summer temperature anomaly of 0 56 c 0 29 c for the southern alps based on palaeo equilibrium lines compares well with local tree ring reconstructions of austral summer temperature reconstructed geopotential height at 1 000 hpa z1000 suggests enhanced southwesterly flow across new zealand occurred during the lia to generate the terrestrial temperature anomalies the mean atmospheric circulation pattern for summer resulted from a crucial reduction of the hse blocking synoptic type highs over and to the west of nz largely settled conditions and increases in both the t and sw trough synoptic types lows passing over nz enhanced southerly and southwesterly flow relative to normal associated land based temperature and precipitation anomalies suggest both colder and wetter than normal conditions were a pervasive component of the base climate state across new zealand during the lia as were colder than normal tasman sea surface temperatures proxy temperature and circulation evidence were used to corroborate the spatially heterogeneous southern hemisphere composite z1000 and sea surface temperature patterns generated in this study a comparison of the composites to climate mode archetypes suggests lia summer climate and atmospheric circulation over new zealand was driven by increased frequency of weak el nino modoki in the tropical pacific and negative southern annular mode activity

sedimentology of latero frontal moraines and fans on the west coast of south island new zealand exposures through the lgm latero frontal moraine loops at sites along the west coast of south island new zealand reveal a depositional environment that was dominated by the progradation of steep fronted debris flow fed fans manifest in crudely stratified to massive diamictons arranged in sub horizontal to steeply dipping clinoforms and containing discontinuous bodies of variably sorted stratified sediment lfa 1 the fans were constructed by debris covered glaciers advancing over outwash plains as recorded by well stratified and horizontally bedded gravels sands and diamicts lfa 0 the ice contact slopes of the fans are offlapped by retreat phase deposits in the form of glacilacustrine depo centres lfa 2 which record the existence of moraine dammed lakes interdigitation of lake rhythmites and subaerial to subaqueous sediment gravity flow deposits documents intense debris flow activity on unstable moraine fan surfaces glacier readvances in all catchments are documented by glacitectonic disturbance and localized hydrofracturing of lfa 2 followed by the emplacement of schist dominated debris flow fed fans lfa 3 inside and over the top of the earlier latero frontal moraine fan loops contorted and disturbed bedding in lfa 3 reflects its partial deposition in supraglacial positions clast lithologies in lfas 1 and 3 reveal that two distinct transport pathways operated during moraine construction with an early period of latero frontal fan construction involving mixed lithologies and a later period of ice contact supraglacial fan construction dominated by schist lithologies from the mountains these two periods of deposition were separated by a period of moraine abandonment and paraglacial reworking of ice contact slopes to produce lfa 2 the occurrence of lfa 3 at all sites indicates that the glacier readvance phase responsible for its deposition was not localized or glacier specific and involved the transfer of large volumes of schist possibly due to rock slope failures onto glacier surfaces the absence of any sediment that could be unequivocally classified as subglacial till reflects the dominance of debris flow and glacifluvial processes in latero frontal moraine construction in this hyper humid west coast setting

study of physical and chemical properties of vitrinites inferences on depositional and coalification controls abstract a detailed study of petrological geochemical textural and coking properties was carried out on vitrains from the puertollano blanzy montceau asturias and teruel the objective was to determine in depth the physical and chemical properties of a series of natural and pure vitrinites of different rank and the influence that the sedimentary and post sedimentary conditions had on them it is demonstrated that although vitrains are almost entirely made up of the huminite vitrinite maceral group they have a different composition thermal behaviour and physical properties thus geochemical and textural properties of blanzy montceau vitrains can be considered to be representative of the telinite the major component in both samples 75 vol at the beginning of the bituminization stage subbituminous high volatile c bituminous coals the characteristics of the puertollano vitrains described here can also be attributed to the telocollinite 80 vol for the high volatile c bituminous coal variations in physico chemical properties between puertollano and blanzy montceau vitrains are due to the differences in the initial composition of organic matter slight differences i e bed moisture content or porosity between vitrains from the two coal seams in the same basin can be attributed to their stratigraphic position several parameters such as s 2 hi oil and extraction yield and fluorescent properties suggest that the puertollano and blanzy montceau vitrains have a lower hydrocarbon potential the relationships between geochemical and textural properties make it possible to distinguish between normal and perhydrous vitrains the two different hydrogen enrichment processes that occur in vitrains from the teruel and asturias basins can be distinguished from the extraction yield data

methane and sulfide fluxes in permanent anoxia in situ studies at the dvurechenskii mud volcano sorokin trough black sea the dvurechenskii mud volcano dmv is located in permanently anoxic waters at 2060 m depth sorokin trough black sea the dmv was studied during the rv meteor expedition m72 2 as an example of an active mud volcano system to investigate the significance of submarine mud volcanism for the methane and sulfide budget of the anoxic black sea hydrosphere our studies included benthic fluxes of methane and sulfide as well as the factors controlling transport consumption and production of both compounds within the sediment the pie shaped mud volcano showed temperature anomalies as well as solute and gas fluxes indicating high fluid flow at its summit north of the geographical center the anaerobic oxidation of methane aom coupled to sulfate reduction sr was repressed in this zone due to the upward flow of sulfate depleted fluids through recently deposited subsurface muds apparently limiting microbial methanotrophic activity consequently the emission of dissolved methane into the water column was high with an estimated rate of 0 46 mol m 2 d 1 on the wide plateau and edge of the mud volcano surrounding the summit fluid flow and total methane flux were lower allowing higher sr and aom rates correlated with an increase in sulfate penetration into the sediment here between 50 and 70 of the methane flux 0 07 0 1 mol m 2 d 1 was consumed within the upper 10 cm of the sediment the overall amount of dissolved methane released from the entire mud volcano structure into the water column was significant with a discharge of 1 3 107 mol yr 1 the dmv maintains also high areal rates of methane fueled sulfide production and emission of on average 0 05 mol m 2 d 1 this is a difference to mud volcanoes in oxic waters which emit similar amounts of methane but not sulfide however based on a comparison of this and other mud volcanoes of the black sea we conclude that sulfide and methane emission into the hydrosphere from deep water mud volcanoes does not significantly contribute to the sulfide and methane inventory of the black sea

oil source rock correlations in the polish flysch carpathians and mesozoic basement and organic facies of the oligocene menilite shales insights from hydrous pyrolysis experiments the oligocene menilite shales in the study area in the polish flysch carpathians are organic rich and contain varying mixtures of type ii type iis and type iii kerogen the kerogens are thermally immature to marginally mature based on atomic h c ratios and rock eval data this study defined three organic facies i e sedimentary strata with differing hydrocarbon generation potentials due to varying types and concentrations of organic matter these facies correspond to the silesian unit and the eastern and western portions of the skole unit analysis of oils generated by hydrous pyrolysis of outcrop samples of menilite shales demonstrates that natural crude oils reservoired in the flysch sediments appear to have been generated from the menilite shales natural oils reservoired in the mesozoic basement of the carpathian foredeep appear to be predominantly derived and migrated from menilite shales with a minor contribution from at least one other source rock most probably within middle jurassic strata definition of organic facies may have been influenced by the heterogeneous distribution of suitable menilite shales outcrops and producing wells and subsequent sample selection during the analytical phases of the study

extractable organic material in fault zones as a tool to investigate frictional stress abstract the detection of a frictional heating signature is an attractive but elusive way to measure frictional stress on exhumed faults with no evidence of melting we present a new paleothermometer for fault zones that utilizes the thermal maturity of extractable organic material to determine the maximum frictional heating experienced by the fault because there are no retrograde reactions in these organic systems maximum heating is preserved we investigate the punchbowl fault an ancient strand of the san andreas fault in southern california according to the methylphenanthrene index for thermal maturity there is no differential heating between the fault and off fault samples indicating that the fault did not get hotter than the surrounding rock during slip additionally the thermal maturity of the rocks falls within the range of heating expected from the bounds on burial depth and time and adds some constraint to the burial depth range simple heating models indicate that the fault must have had either 1 an extremely low shear stress during slip 2 an active slipping zone thicker than 1 mm or 3 earthquakes smaller than m6 to lack a differential heating signature after 44 km slip

the oligocene maikop series of lahich eastern azerbaijan paleoenvironment and oil source rock correlation abstract the maikop formation deposited in eastern azerbaijan during oligocene and early miocene represents a prolific source unit for the oils found within the southern gobustan area and the kura depression based on biomarker characteristics the oils are believed to have originated from a clastic source rock deposited in an anoxic to suboxic transitional marine environment with low to moderate input of terrigenous organic matter however due to the thermal immaturity of accessible maikop rocks oil source rock correlation based on biomarker fingerprints is hampered the results from a sedimentary succession sampled in the shemakha gobustan area near the village of lahich revealed the presence of marginally mature rr 0 6 0 7 maikop rocks based on lithology geochemical data and paleontological analyses the sampled section contains upper eocene and lower oligocene sediments palynological analyses of dinoflagellate cysts indicate an early rupelian to early chattian oligocene age for the upper part of the investigated maikop succession however the stratigraphic position of the middle and lower part of the succession remains unclear maceral composition as well as biomarker and stable isotope c n data indicate a major contribution of aquatic organisms and variable inputs from macrophytes and land plants to organic matter deposition during the oligocene microbial communities most probably included heterotrophic bacteria and cyanobacteria as well as green sulfur bacteria higher inputs of terrigenous organic matter occurred during deposition of the lower part of the succession increased remineralisation of organic matter in the water column is suggested to result in low toc and hydrocarbon contents as well as 15n enriched total nitrogen of the eocene to earliest oligocene sediments organic carbon accumulation during the oligocene occurred in a stratified episodically euxinic environment this is indicated by low toc s ratios and higher contents of aryl isoprenoids in several samples from the upper units a moderate to good oil source rock correlation with oils from the kura depression is indicated by sterane and triterpane fingerprints as well as carbon isotopic composition of hydrocarbon fractions

characteristics of collisional orogens with low topographic build up an example from the carpathians sequence stratigraphy in the hinterland kinematic analysis of thin skinned thrusting in the foreland and thermochronological tracking of exhumation in the orogenic core are combined to quantify the mechanics of an orogen with low topographic build up the carpathian system demonstrates that collisional deformation can couple and thicken the lower orogenic plate along reverse faults that dip more steeply than the subduction zone defining a foreland coupling type of collision near the surface this is expressed by wide antiforms in the upper plate and the thin skinned orogenic wedge a sequence stratigraphic analysis of the back arc transylvanian basin demonstrates that the sedimentary architecture records orogenic uplift pulses with both short and long wavelengths these correspond to the activation of individual thrust sheets in the thin skinned wedge and to lower plate coupling events respectively

hydrothermal breccia related cumoau mineralization in late precambrian granites western cape province south africa abstract hydrothermal breccia bodies with cu mo au mineralization are present in a leucogranite related to the precambrian cape granite suite the host rock is typical of anorogenic a type associations ranging in composition from quartz syenite to alkaligranite the quartz syenites contain na ca amphiboles and range from amphibole to biotite amphibole and leucoratic syenites a major hydrothermal event affecting the alkaligranite took place at 450 c co 2 overpressure caused the first brecciation event the breccias are present in the alkaligranite and on the contact of alkaligranite and quartz syenites at least three stages of brecciation are recognizable the latter stage typical of low temperature epithermal conditions and siderite enrichment cu mineralization is restricted mainly to the breccias and highest values are obtained in sheeting zones bordering the intensely brecciated areas au and mo mineralization is erratic and although the breccias are generally enriched in these two elements high values are typically found in alkaligranite not affected by brecciation

correlation of late quaternary moraines impact of climate variability glacier response and chronological resolution abstract the last decade has seen a global surge in the number and resolution of well dated geomorphological reconstructions of mountain glacier fluctuations and former ice sheet extents this has been facilitated by the widespread deployment of large samples of terrestrial cosmogenic nuclide dating tcnd allowing more sophisticated probability analyses for reducing the statistical uncertainty of moraine ages and testing of correlations at local regional and hemispheric scales geochronological advances in the field laboratory and on model calibration have taken place in parallel with modelling of palaeoclimate based on glacier reconstructions and of glacier sensitivity to temperature and precipitation forcing in spite of these advances basic conceptual issues remain this review questions whether the technical leap forward in dating has encouraged us to over reach our interpretive limits particularly in terms of the concept and practice of correlation we propose that to enable reliable correlation glacier chronologies should first be examined for their climatic integrity spatial coherence and chronological robustness even with excellent dating interpretive complexity remains due to complex climate signals and glacier response characteristics and to erosion censoring of the landform record all are issues which must be addressed to avoid either spurious lumping correlation or splitting differentiation of glacier chronologies and thus misinterpretation of the climatic significance of reconstructed glacier advances we suggest that the reliability of correlation is no better than the weakest link in the chain of reasoning which connects climatic fluctuations with dated landforms and sediments improved dating means that poor chronological resolution is less likely to be the limiting factor for correlation but shifts the focus onto other less quantifiable sources of uncertainty these conceptual statements are exemplified with reference to holocene glacial chronologies of contrasting mid latitude environments in southern norway iceland and new zealand

holocene and latest pleistocene alpine glacier fluctuations a global perspective abstract alpine glacier fluctuations provide important paleoclimate proxies where other records such as ice cores tree rings and speleothems are not available about 20 years have passed since a special issue of quaternary science reviews was published to review the worldwide evidence for holocene glacier fluctuations since that time numerous sites have been discovered new dating techniques have been developed and refined climatic hypotheses have been proposed that contribute to a better understanding of earth s climate system this special volume includes 12 papers on holocene and latest pleistocene alpine glacier fluctuations that update the seven review papers from 1988 major findings of these 12 papers include the following many but certainly not all alpine areas record glacier advances during the younger dryas cold interval most areas in the northern hemisphere witnessed maximum glacier recession during the early holocene with some glaciers disappearing although a few sites yield possible evidence for advances during the 8 2 ka cooling event in contrast some alpine areas in the southern hemisphere saw glaciers reach their maximum post glacial extents during the early to middle holocene in many parts of the globe glaciers reformed and or advanced during neoglaciation beginning as early as 6 5 ka neoglacial advances commonly occurred with millennial scale oscillations with many alpine glaciers reaching their maximum holocene extents during the little ice age of the last few centuries although the pattern and rhythm of these glacier fluctuations remain uncertain improved spatial coverage coupled with tighter age control for many events will provide a means to assess forcing mechanisms for holocene and latest pleistocene glacial activity and perhaps predict glacier response to future impacts from human induced climate change

the temporal significance of transitions from melting to calving termini at glaciers in the central southern alps of new zealand termini of valley glaciers in the central southern alps are undergoing a three phase sequence of retreat that began in the 1950s an initial phase of melting and slow downwasting under thickening supraglacial debris mantles is associated with stationary or slowly retreating termini this is followed by a transitional phase of disruption of insulating debris mantles allowing the rapid growth of shallow thermokarst lakes the shape and location of which vary according to glacier gradient and marginal topography a third phase of rapid calving retreat of ice cliffs into deepening proglacial lakes develops from the transitional phase at no stage are terminal responses simply related to climate present transitions to calving retreat are related to the morphology of glacier termini particularly to large outwash heads landform evidence indicates that similar calving phases do not appear to have occurred since late pleistocene deglaciation so that present changes to glacier termini are of great significance

a novel series of benzohopanes widespread in sediments abstract a novel series c 31 c 35 of benzohopanes cyclized at the c 16 position has been characterized by gas chromatography mass spectrometry and nmr structural elucidation of the usually predominant c 31 member the 4 methylbenzo 16 17 21 22 29 30 trinorhop 16 ene isolated from the messel shale germany these biological markers of bacterial origin seem to be widely distributed in sediments and to show low specificity with regard to the depositional environment although they are well represented in evaporites up to now they have been detected only in thermally immature samples which could reflect either a relative fragility or other possibilities of transformation as compared to the regular benzohopanes cyclised at c 20

temperature sensitive tree ring width chronologies of pink pine halocarpus biformis from stewart island new zealand abstract long instrumental or proxy climatic records are scarce for the southern hemisphere relative to many northern regions but are essential for a global perspective of past climate variability in this paper we describe two tree ring width chronologies of pink pine which are the first published for stewart island new zealand 47 s 168 e one of the southernmost forested land masses on the globe a chronology for western central stewart island doughboy rakeahua extends from 1682 to 1990 the other for southern stewart island pegasus from 1690 to 1991 both series are positively correlated with warm season surface air temperatures for southern new zealand and vicinity although there are shorter intervals of comparable warmth the highest 20 year periods of growth during the past 300 years occurred during the middle 1950s 1970s coinciding with record warming since around 1950 in new zealand chronologies developed from two related species silver pine lagarostrobus colensoi from ahaura western south island new zealand and huon pine lagarostrobus franklinii from tasmania also indicate recent warming which is unusual although not statistically unprecedented within the contexts of the past 642 and 2290 years of record respectively

a detailed 31 000 year record of climate and vegetation change from the isotope geochemistry of two new zealand speleothems abstract uranium series dating and stable isotope analyses of two speleothems from northwest nelson new zealand record changes in regional climate and local forest extent over the past 31 000 years oxygen isotope variation in these speleothems primarily represents changes in the meteoric waters falling above the caves possibly responding to latitudinal changes in the position of the subtropical front in the tasman sea seven positive excursions can be identified in the oxygen isotope record which coincide with periods of glacier advance known to be sensitive to northward movement of the subtropical front four glacier advances occurred during oxygen isotope stage 2 with the most extreme glacial conditions centered on 19 000 cal yr b p 2 an excursion in the oxygen isotope record from 13 800 to 11 700 cal yr b p provides support for a previously identified new zealand glacier advance at the time of the younger dryas stade but suggests it began slightly before the younger dryas as recorded in greenland ice cores carbon isotope variations in the speleothems record changes in forest productivity closely matching existing paleovegetation records on the basis of vegetation changes stage 2 glacial climate conditions terminated abruptly in central new zealand from 15 700 to 14 200 cal yr b p evidence of continuous speleothem growth at one site suggests that depression of the local treeline was limited to 600 700 m below its present altitude throughout the last 31 000 years

depositional environment and hydrocarbon source potential of the oligocene ruslar formation kamchia depression western black sea abstract the oligocene ruslar formation is a hydrocarbon source rock in the kamchia depression located in the western black sea area depositional environment and source potential of the predominantly pelitic rocks were investigated using core and cuttings samples from four offshore wells in these wells the ruslar formation is up to 500 m thick based on lithology and well logs the ruslar formation is subdivided from base to top into units i vi dysoxic to anoxic conditions and mesohaline to euhaline salinities prevailed during deposition of the ruslar formation relatively high oxygen contents occurred during early solenovian times lower part of unit ii when brackish surface water favoured nannoplankton blooms and the deposition of bright marls solenovian event anoxic conditions with photic zone anoxia were established during late oligocene times units iii and iv and probably reflect a basin wide anoxic event in the eastern paratethys during kalmykian times organic carbon content in the ruslar formation is up to 3 autochthonous aquatic and allochthonous terrigenous biomass contribute to the organic matter relatively high amounts of aquatic organic matter occur in the lower part of the ruslar formation units i and ii and in its upper part unit vi diatoms are especially abundant in the lower part of unit vi the kerogen is of type iii and ii with hi values ranging from 50 to 400 mghc gtoc units i and ii pshekian lower solenovian are characterized by a fair to good potential to produce gas and oil but potential sources for gas and oil also occur in the upper oligocene units iv vi

sensitivity of biomarker properties to depositional environment and or source input in the lower toarcian of sw germany abstract a sequence of lower toarcian sediments which are highly contrasting in their depositional environment over a 5 m depth interval has been investigated in detail for the variability of geochemical properties which are used for source characterization and oil to source correlation lower liassic marls are representative of a well aerated shallow water environment in contrast to the immediately overlying bituminous shales which are deposited under extremely reducing conditions various properties have been found to vary considerably within these two units amongst the most important are carbon isotopic composition of the kerogen the pristane phytane ratios nickel as opposed to vanadyl porphyrins and the c27 dia regular steranes although maturation within the profile does not change some of the maturation dependent biomarker properties such as the monoaromatic steroid side chain cracking and the tm ts ratio exhibit large changes which can be assigned to diagenetic processes another maturation dependent property the 20s 20r epimerization of c29 steranes exhibits smaller changes which could also be due to early diagenetic processes the study suggests that reducing and oxidizing conditions i e eh and ph in the sediment exert an influence on several biomarker precursor product pathways in maturation studies initial variations due to depositional conditions have therefore to be taken into account

late holocene climate variability from lake pupuke maar auckland new zealand abstract spectral analyses of quasi annual organo diatomaceous laminae couplets in an auckland maar lake indicate brief sub decadal scale episodes with strong spectral power and long periods of weak to no spectral power between c 1700 to c 550 cal yr bp laminae couplet thickness appears to be a function of changes in wind flow over the basin with enhanced wind flow deepening the mixing zone and providing additional nutrients for laminae formation aeolian dust from australia amplifies the wind signal spectral signals in the high power episodes are focused in

assessment of multispectral glacier mapping methods and derivation of glacier area changes 1978 2002 in the central southern alps new zealand from aster satellite data field survey and existing inventory data we have measured the glacier area changes in the central southern alps new zealand between 1978 and 2002 and have compiled the 2002 glacier outlines using an image scene from the advanced spaceborne thermal emission and reflection radiometer aster three automated classification methods were tested 1 band ratio 2 normalized difference snow index and 3 supervised classification the results were compared with the glacier outlines photo interpreted from the aster data and were further validated using gps aided field mapping of selected test glaciers the aster 3 4 band ratio provided the best results however all the classification methods failed to extract extensive debris covered parts of the glaciers therefore the photo interpreted 2002 outlines were used when comparing with the existing 1978 glacier inventory derived from aerial photographs our results show a 17 reduction of glacier area mainly driven by the retreat of the large valley glaciers despite the large climatic gradient from west to east glaciers on both sides of the main divide lost similar percentages of area except franz josef and fox glaciers which advanced smaller glaciers were found to have changed very little in the study period

a 22 month record of surface meteorology and energy balance from the ablation zone of brewster glacier new zealand multi annual records of glacier surface meteorology and energy balance are necessary to resolve glacier climate interactions but remain sparse especially in the southern hemisphere to address this we present a record from the ablation zone of brewster glacier new zealand between october 2010 and september 2012 the mean air temperature was 1 2 c at 1760 m a s l with only a moderate temperature difference between the warmest and coldest months 8 c long term annual precipitation was estimated to exceed 6000 mm a 1 with the majority of precipitation falling within a few degrees of the freezing level the main melt season was between november and march 83 of annual ablation but melt events occurred during all months annually net radiation was positive a source of energy and supplied 64 of the melt energy driven primarily by net shortwave radiation net longwave radiation was often positive during cloudy conditions in summer demonstrating the radiative importance of clouds during melt turbulent sensible and latent heat fluxes were directed towards the surface in the summer months accounting for just over a third of the energy for melt 34 the energy gain associated with rainfall was small except during heavy events in summer

the southern hemisphere westerlies in the australasian sector over the last glacial cycle a synthesis abstract the southern hemisphere westerlies in the southwest pacific are known to have waxed and waned numerous times during the last two glacial cycles though even semi continuous histories of the westerlies extend back no more than about 20 000 years we have good evidence for at least three scales of events a westerly maximum occurs at the last glacial maximum there is less conclusive evidence for another westerly maximum in the late holocene and for a minimum at ca 11 ka it is too early to ascribe even a cycle to these data but there are grounds to suggest that milankovitch precessional forcing may underlie the observed pattern there is also a quasi 2600 year cycle present in antarctic ice cores that appears to correlate to variation in westerly flow there is strong centennial scale variability in historical times the little ice age lia ca 1400 1850 was associated with a poleward shift in the circumpolar trough in the southern ocean strengthened westerly circulation over tasmania and a strengthening of southwesterly circulation and neoglaciation in southern new zealand while the preceding period 800 1400 ad was less certainly marked by reduced westerly flow from modern records we know that decadal and inter annual variability is important e g pacific decadal oscillation high latitude mode also known as the antarctic oscillation el nino southern oscillation only a minority of the proxies examined can identify changes on these temporal scales but data from tree rings ice cores and laminated lake sediments do indicate systematic changes in these phenomena through time rossby wave patterns are shown to play a critical role in long duration events as well as at the synoptic scale we conclude that westerly circulation is as strong now as at any time in the last glacial cycle in addition changes in latitudinal boundaries in the westerlies may be nearly as large in inter annual zonal shifts ca 2 maximum as in glaciation interglaciation movements ca 3 4 there is however reasonable evidence of strengthening weakening across much of the westerly belt at westerly maxima minima such as the lia early holocene

a cosmogenic nuclide chronology of the last glacial transition in north west nelson new zealand new insights in southern hemisphere climate forcing during the last deglaciation we present a new glacial chronology for the last glacial interglacial transition c 20 to 10 ka from the cobb valley nw nelson new zealand based on a suite of 10be and 26al cosmogenic exposure ages this chronology describes one of the most comprehensive deglaciation sequences from a late quaternary valley system in the southern hemisphere we chronicle the decay from the last local glacial maximum as follows onset of the last deglaciation that commenced no earlier than 18 19 ka followed by numerous short term still stands and or minor re advances over the ensuing 3 4 kyr and complete evacuation of ice by 14 ka we find no evidence to indicate a late glacial re advance commensurate with the northern hemisphere younger dryas chronozone the absence of a major glacial re advance in this valley during the latter stages of the last glacial interglacial transition lgit precludes a thermal decline in excess of about 3 c and suggests no decline the absence of late lgit re advances in the mountains of north west nelson while deglacial readvances occurred in the main ranges of the southern alps can be best explained if westerly wind forcing rather than large scale thermal decline is the primary control on glacier fluctuations at least during the deglaciation these findings challenge models of global climate change predicated on synchrony of millennial scale glacial transitions due to thermal changes between northern and southern hemispheres

evidence against a significant younger dryas cooling event in new zealand pollen records of deglacial sequences from northwest nelson new zealand demonstrate that there was no significant temperature decline associated with the younger dryas in new zealand records of glacial advances at this time were either the product of increased snow accumulation under enhanced precipitation regimes or random variation rather than the result of a regional thermal decline this finding supports those models of younger dryas initiation that require neither enhanced westerly circulation nor significant thermal decline in the southern hemisphere

lateglacial landscape and vegetation change and the younger dryas climatic oscillation in new zealand abstract lateglacial sequences in new zealand show progressive afforestation and landscape stabilization reflecting a warming climate between 14 500 bp and 11 500 bp afforestation and landscape stability was achieved throughout most of the north island and the northwest sector of the south island in the south island scrub and tree ferns were replacing previous grasslands in the east by 11 000 bp and broadleaved forest was spreading in the west no significant reversals of these trends occurred and afforestation was complete by 9500 bp glaciers of the high central part of the southern alps made a series of advances between 14 000 and 9000 bp most of these advances are poorly dated but two moraines are of younger dryas age glacial advances in the face of the general lateglacial warming trend may have been driven by stronger westerly winds increasing snowfall on high altitude neves and by reduced ablation as a consequence of moist cloudy low insolation summers the cause of the northern hemisphere younger dryas cooling is still uncertain and expected southern hemisphere responses may differ according to the mechanism proposed for the cooling poor chronological resolution and apparent conflict between the various types of evidence for climatic change make detection of an unambiguous younger dryas in new zealand problematical

catastrophic landslides glacier behaviour and moraine formation a view from an active plate margin the influence of large bedrock landslides rock avalanches on the behaviour of glaciers is incompletely recognised here we present an example from an active tectonic margin in south island new zealand where large earthquakes leave a significant imprint on glacial records we demonstrate that terminal moraines on the western side of the southern alps record both ordinary i e climate driven and landslide initiated glacial advances following consideration of the processes involved in rock avalanche initiated moraine construction we suggest ways of determining the nature of the advance that built the terminal moraine the implications of these observations are important in breaking the conventional linkage of individual terminal moraines with climate forcing

water column structure during deposition of middle devonian lower mississippian black and green gray shales of the illinois and michigan basins a biomarker approach abstract the extractable organic matter of organic rich black shales and associated organic poor bioturbated green gray shales of the illinois and michigan basins of north america is analyzed to constrain the water column structure during their deposition all black shale samples contain derivatives of the biomarker isorenieratene a diaromatic carotenoid pigment produced exclusively by the brown strain of the green sulfur bacteria chlorobiaceae chlorobiaceae are phototrophic organisms requiring euxinic anoxic and sulfidic conditions to survive and the presence of isorenieratene derivatives indicates that the middle devonian early mississippian epeiric seas of north america experienced bottom water euxinic conditions during black shale deposition analysis of green gray shales also reveals the presence of isorenieratene derivatives and in some cases isorenieratane the highly bioturbated fabric of these sediments indicates the presence of oxygen in bottom waters during their deposition thus we suggest that short term shoaling of the oxycline across the basin slope may have occurred during their deposition though they were deposited predominantly under an oxygenated water column i e above the chemocline most green gray shales contain three pseudohomologous series of branched alkanes with quaternary substituted carbon atoms baqcs which are absent in black shale samples recent studies suggest that baqcs are produced by benthic chemoautotrophs dwelling at the redox boundary separating anoxic sediments from moderately oxygenated waters comparison of the biomarker content i e regular isoprenoid baqcs between black and green gray shales indicates different sources of organic matter and suggests that phytoplanktonic productivity in the upper water column was enhanced during black shale deposition the results of this study indicate that the alternation of green gray and black shales in these basins results from the vertical fluctuations of the chemocline these fluctuations seem to be driven by changes in phytoplanktonic productivity our data when associated to previous studies of other black shales from canada and europe confirm that photic zone euxinia was a widespread feature of low latitude epeiric seas during the middle devonian lower mississippian

new data on the vrancea nappe moldavidian basin outer carpathian domain romania paleogeographic and geodynamic reconstructions a study has been performed on the cretaceous to early miocene succession of the vrancea nappe outer carpathians romania based on field reconstruction of the stratigraphic record mineralogical petrographic and geochemical analyses extra basinal clastic supply and intra basinal autochthonous deposits have been differentiated appearing laterally inter fingered and or interbedded the main clastic petrofacies consist of calcarenites sub litharenites quartzarenites sub arkoses and polygenic conglomerates derived from extra basinal margins an alternate internal and external provenance of the different supplies is the result of the paleogeographic re organization of the basin margins system due to tectonic activation and exhumation of rising areas the intra basinal deposits consist of black shales and siliceous sediments silexites and cherty beds evidencing major environmental changes in the moldavidian basin organic matter rich black shales were deposited during anoxic episodes related to sediment starvation and high nutrient influx due to paleogeographic isolation of the basin caused by plate drifting the black shales display relatively high contents in sub mature to mature type ii lipidic organic matter good oil and gas prone source rocks constituting a potentially active petroleum system the intra basinal siliceous sediments are related to oxic pelagic or hemipelagic environments under tectonic quiescence conditions although its increase in the oligocene part of the succession can be correlated with volcanic supplies the integration of all the data in the progressive reorientation of convergence direction carpathian model and their consideration in the framework of a foreland basin led to propose some constrains on the paleogeographic geodynamic evolutionary model of the moldavidian basin from the late cretaceous to the burdigalian

have the southern westerlies changed in a zonally symmetric manner over the last 14 000 years a hemisphere wide take on a controversial problem the prevailing view in the palaeoclimate literature of the last 20 years is that the southern westerly winds sww were intensified over southern australia and tasmania during the warmer than present early holocene 11e8 ka at similar latitudes on the opposite side of the southern mid latitudes palaeoclimate studies have suggested a poleward shift of the northern edge of the westerlies and focusing at 49 s in southern south america this zonal asymmetry contrasts with the modern day zonal symmetry displayed by the sww and poses a formidable challenge to an understanding of the modes of climatic variability of the southern extra tropics this paper presents an updated synthesis of continuous radiocarbon dated palaeoenvironmental data from the westerlies zone of influence in all southern hemisphere continents synchronous multi millennial trends in moisture vegetation fire and hydrologic balance are remarkably consistent with the way the sww changes impact upon the climate in southern hemisphere landmasses in the modern climate considering the modern relationships between local precipitation and zonal wind speeds it is suggested that the sww changed in a zonally symmetric manner at multi millennial scale between 14 and 5 ka regional asymmetry develops after 5 ka across the southern hemisphere with a pattern of precipitation anomalies akin to the modern functioning of el nino e southern oscillation which started w6200 years ago

organic matter maturity and hydrocarbon potential of the lower oligocene menilite facies in the eastern flysch carpathians tarcău and vrancea nappes romania abstract bulk organic geochemical and molecular composition data have been used to analyse the hydrocarbon potential and organic matter maturity of the lower oligocene menilite facies from two adjacent tectonic units of the eastern flysch carpathians tarc u and vrancea nappes romania due to the importance of these source rocks in hydrocarbon exploration in entire paratethys realm the data show strong variability in organic matter quantity and quality organic carbon content reaches peak values in the siliceous facies of the lower menilite member up to 8 6 wt toc which contains type ii kerogen with increasing contribution of flysch sedimentation mixed type ii iii kerogen gains importance the biomarker distribution reveals strong variation in the supplied organic matter common for flysch influenced sedimentary environments terrigenous input is marked by epicuticular wax imprint in n alkane distribution and occurrence of conifer biomarkers while marine organic matter origin is expressed by the occurrence of short chain n alkanes and hopanes especially in the siliceous facies thus these source rocks can be classified as oil prone and subordinately mixed oil gas prone the maturity in the outer tectonic unit vrancea is low t max 425 c r o 0 4 but increases towards the inner tarc u nappe t max 430 c r o 0 5 reaching onset of hydrocarbon generation the studied rocks have good petroleum potential but hydrocarbons were generated only in more mature tarc u nappe where solid bitumen veins were observed bitumen impregnation of numerous vitrinite grains possibly suppressed vitrinite reflectance thus leading to more accurate maturity assessment based on molecular proxies biomarker maturity indices the observed difference in maturity levels between the nappes results from the more inner position of the sampled tarc u nappe succession within the orogen relative to the vrancea unit this is related to different burial histories as well as variation in subsequent erosion and exhumation levels the actual hydrocarbon potential in the studied area varies due to local interplay of these critical factors

atmospheric circulation and variations in scandinavian glacier mass balance abstract mountain glaciers in scandinavia are currently advancing while most of the monitored mountain glaciers of the world are retreating we examine atmospheric circulation variability and compare changes in air pressure indices to changes in the mass balance of glaciers in the northeastern part of the atlantic ocean the glacier mass balance correlates well with the strength of maritime flow in both winter and summer the presence of high pressure over the barents sea being a critical factor in summer the advance of scandinavian glaciers is due partly to persistently strong westerlies over the northeastern atlantic during post 1980 winters and partly to cold summertime flow which together have helped maintain positive glacier net balance by decreasing ablation since 1980

effects of source thermal maturity and biodegradation on the distribution and isomerization of homohopanes in petroleum abstract the distributions of c31 c35 17 21 h homohopanes in marine petroleums can be used to describe redox conditions in the source rock depositional environment for example high c35 homohopane indices c35 c31 c35 are typical of petroleums generated from source rocks deposited under anoxic marine conditions where the c35 backbone of the precursor bacteriohopanetetrol is preferentially preserved homohopane distributions have been used to distinguish petroleums from different organic facies of the same source rock homohopane distributions are altered by secondary processes for example the c35 homohopane index decreases with increasing api gravity and thermal maturity of related oils from the monterey formation offshore california similar decreases in the homohopane index are observed for expelled oils from monterey source rock during hydrous pyrolysis biodegradation can result in selective loss of high or low molecular weight homologs apparently depending on the bacterial population in the reservoir bacterial demethylation of homohopanes appears necessary to explain 25 norhopanes in at least one biodegraded oil hydrous pyrolysis studies of the phosphatic and siliceous members in the monterey formation show that identical heating conditions result in different homohopane c 22 epimer ratios furthermore a reversal in the trend of the epimer ratio at high experimental temperatures is observed for the phosphatic but not for the siliceous lithology this could be caused by the combined effects of isomerization and differential thermal destruction of epimers at high temperatures possibly mediated by rock mineralogy

the early twentieth century arctic high fact or fiction reconstructions of monthly mean sea level grid point pressure from station pressure data over the arctic region using an objective technique have revealed two serious errors in the gridded data first all gridded data from the u s historical weather map series for the arctic ocean area away from the north atlantic sector appears to be between 4 and 6 mb too high before about 1931 the semi permanent arctic high produced in the early historical map series was the result of a lack of basic station data and the belief amongst many north american meteorologists of the 1920s and 1930s of the existence of a polar or glacial anticyclone the second error affects only north western north america for the years 1899 1909 here pressure is again too high compared with reconstructed data the cause of this error is not immediately apparent but is probably the result of an erroneous correction to sea level for stations in the region both errors seriously affect the homogeneity of the gridded arctic series the objective scheme used to reveal the errors can also be used to derive correction factors for the gridded data prior to 1931

the last glacial interglacial transition lgit in south westland new zealand paleoecological insight into mid latitude southern hemisphere climate change abstract high resolution pollen stratigraphy from three peat cores located within 20 km of lateglacial moraines in south westland new zealand provide detailed records of climate change during the last glacial interglacial transition lgit the pollen record shows the replacement of grassland by shrubland prior to ca 15 300 14 c yr bp 18 300 cal yr bp followed by the progressive development of broadleaf shrubland and scattered forest prior to ca 12 000 14 c yr bp 14 400 cal yr bp local vegetation changes around the time of the younger dryas chronozone 11 10 ka 14 c bp are evident but are not necessarily a result of regional climate cooling vegetation changes between ca 12 000 and 10 000 14 c yr bp 14 400 and 11 400 cal yr bp indicate a period of increased precipitation tall podocarp forest similar to that of the contemporary forest was well established by ca 10 000 14 c yr bp 11 400 cal yr bp a period of increased westerly circulation over southern new zealand is considered to be the most likely mechanism for causing the increased precipitation between ca 12 000 and 10 000 14 c yr bp 14 300 and 11 400 cal yr bp increased precipitation would also provide a mechanism for initiating lgit ice advance in the area data from these records show some support for global climate change models that propose inter hemispheric linkage but may be more supportive of a climate change model that incorporates an increased westerly circulation over southern new zealand during the lgit

facies evolution and stratigraphic correlation in the early oligocene tard clay of hungary as revealed by maceral biomarker and stable isotope composition abstract hydrocarbon source rocks i e tard clay formation containing type ii organic matter were deposited in the hungarian paleogene basin during lower oligocene a major contribution of aquatic organisms green algae dinoflagellates chrysophyte algae and minor inputs from macrophytes and land plants to organic matter accumulation is indicated by n alkane distribution patterns composition of steroids and 13c of hydrocarbon biomarkers microbial communities included heterotrophic bacteria cyanobacteria chemoautotrophic bacteria as well as green sulphur bacteria the presence of methanotrophic bacteria is indicated by 13c depleted hop 17 21 ene higher inputs of terrestrial organic matter occurred during deposition of the lower and uppermost units of the tard clay formation the terpenoid hydrocarbon composition argues for angiosperm dominated vegetation in the area of the hungarian paleogene basin diterpenoid hydrocarbons derived from the resins of conifers are about 2 3 enriched in 13c compared to the angiosperm biomarkers environmental conditions changed from marine to brackish accompanied by oxygen depletion in the lower parts of the water column organic carbon accumulation during this period was a consequence of stagnant bottom water conditions in the hungarian paleogene basin due to salinity stratification this is indicated by low pristane phytane ratios varying from 0 27 to 1 44 enhanced ratios of dimethylated versus trimethylated mttcs 0 14 0 59 and the presence of aryl isoprenoids from 0 4 to 14 1 g g toc a major marine incursion is evidenced by stable isotope ratios of organic matter and carbonates in the uppermost member of the tard clay a transition from brackish towards normal marine conditions is proposed up to 3 anoxic cycles are recognized in the drill core sections separated by minima in pristane phytane ratios and maxima in the depth trends of di tri methylated mttcs and aryl isoprenoid concentrations in combination with the position of maxima of 13c of carbonate and organic matter and an abrupt decrease in perylene concentrations the cycles can be used for intra formational correlation of the tard clay