dinoflagellate cysts sea level changes and planktonic foraminifers across the cretaceous tertiary boundary at el haria northwest tunisia abstract dinoflagellate cysts and planktonic foraminifers have been studied from the cretaceous tertiary k t boundary interval at el haria northwest tunisia a high resolution integrated biostratigraphy is presented the k t boundary is drawn at the level of extinction of cretaceous planktonic foraminifers and is coincident with the first occurrence of the dinoflagellate cyst species danea californica the final extinction of planktonic foraminifers is foreshadowed by a reduction in their total abundance some 5 kyr earlier at the base of the boundary clay this reduction is coeval with reported anomalies in siderophyle elements and 13 c values in the same area dinoflagellate cysts do not show accelerated rates of extinction at k t time associations of dinoflagellate cysts however change drastically and parallel changes in relative numbers of sporomorphs spores and pollen and in the quantity of land derived organic matter jointly these changes reflect a rapidly falling sea level during the final 17 kyr of the mesozoic which culminates at the level of the k t boundary this steep sea level fall at k t time represents a peak regressive pulse at the end of the well documented latest cretaceous regressive trend this short term sea level fall might show to be a wide spread phenomenon which could have caused an excess shrinking of the already reduced areal extent of marginal seas since deep waters in cretaceous oceans were primarily produced in shallow marginal seas the rate of formation of deep water might have been minimized at k t time minimum rates of formation of deep water might have curtailed the slow upward mixing of relatively cool and nutrient rich deeper water through which the thermocline weakened and surficial waters became depleted in nutrients consequently phytoplankton productivity rapidly diminished which in combination with a weakened thermal gradient pushed the highly depth stratified cretaceous planktonic foraminiferal fauna to extinction over a period of time of some 5 kyr guembelitria cretacea was the sole planktonic foraminifer which could accommodate to the low productivity conditions the oscillating rise in sea level at the beginning of the cenozoic reinforced the upward mixing of relatively cool and nutrient rich deeper water steepened the thermocline and replenished the photic layer with nutrients concomitant niche differentiation in the photic layer progressively stimulated morphological innovation amongst early cenozoic planktonic foraminifers the final return of normally sized planktonic foraminifers and of stable and well balanced dinoflagellate cyst associations at about 125 kyr after the k t boundary seems to indicate that primary productivity and niche differentiation in the photic layer begin to revert to optimum levels the earliest cenozoic planktonic foraminiferal species globoconusa minutula and parvularugoglobigerina fringa are thought to have developed from a benthic foraminiferal species rather than having a planktonic ancestry

timing of the acadian orogeny in northern new hampshire abstract new u pb geochronology constrains the timing of the acadian orogeny in the central maine terrane of northern new hampshire sixteen fractions of one to six grains each of zircon or monazite have been analyzed from six samples 1 an early syntectonic diorite that records the onset of the acadian 2 a schist a migmatite and two granites that together record the peak of the acadian and 3 a postkinematic pluton that records the end of the acadian zircon from the syntectonic wamsutta diorite gives a 207pb 206pb age of circa 408 ma the time at which the boundary between the deforming orogenic wedge and the foreland basin was in the vicinity of the presidential range this age agrees well with the emsian position of the northwest migrating acadian orogenic front and records the beginning of the acadian in this part of the central maine terrane we propose a possible acadian tectonic model that incorporates the geochronologic structural and stratigraphic data monazite from the schist migma

late eocene to early oligocene dinoflagellate cysts from the priabonian type area northeast italy biostratigraphy and paleoenvironmental interpretation abstract marginal marine late eocene through early oligocene dinoflagellate cyst successions have been studied from the type area of the priabonian stage northeast italy the results allow the recognition of dinoflagellate zones previously defined in bio and magnetostratigraphically well calibrated pelagic sequences from central italy thus providing a first order correlation of the priabonian stage to the standard chronostratigraphic scale with unprecedented precision within this detailed biostratigraphic framework successive shifts in the composition of the dinoflagellate cyst assemblages are interpreted in terms of sea level and sea surface temperature sst fluctuations the evaluation of ecologically and sedimentary controlled changes in the composition of dinoflagellate cyst assemblages in combination with sequence stratigraphic analysis allows the reconstruction of third and fourth order sea level fluctuations the third order sea level fluctuations appear to correspond to exxon cycles ta4 1 4 5 the stratigraphically and palaeoenvironmentally important late eocene dinoflagellate cyst species glaphyrocysta priabonensis sp nov is formally described

paleocene coccoliths and coccospheres in deposits of the maastrichtian stage at the type locality and type area in se limburg the netherlands abstract three so called tertiary newcomer coccoliths cruciplacolithus primus neobiscutum parvulum and neobiscutum romeinii were found in what are generally believed to be upper maastrichtian deposits at the enci quarry st pietersberg near maastricht the curfs quarry near houthem and from the maastrichtian part of the k t boundary section of the cave system at geulhemmerberg near valkenburg southeastern limburg the netherlands the mentioned species appear already far below the berg en terblijt horizon at the curfs quarry and geulhemmerberg which is actually supposed to mark the k t boundary at the enci quarry they range throughout the maastricht formation above the horizon of lichtenberg the specimens are well preserved and originate from undisturbed sediment layers thus it seems that they were not transported into the maastrichtian sediments by water circulation or burrowing effects the state of preservation and the presence of intact coccospheres indicate that they are autochthonous c primus n romeinii and n parvulum are extremely small in size 800 nm to 2 0 m implying that a scanning electron microscope sem must be set at least to 3 k magnification in order to detect them with a light microscope lm at 1 k they cannot be classified which is probably the reason why previous investigators who studied the same sections based on lm did not mention these species from the upper maastrichtian they furthermore appear in very low numbers contributing to around 1 of an associated calcareous nannoflora which is equivalent to the assemblage of the cc26 nephrolithus frequens zone of cepek and hay 1969 the biostratigraphic setting of the enci quarry curfs quarry and geulhemmerberg have been the subject of a long and controversial discussion whether the exposed sediments still belong to the upper maastrichtian or represent the lower tertiary reworking of macrofossils and microfossils or autochthony of index fossils had been discussed and used to support the different opinions about the chronostratigraphy of these sections up to now there has not been any contribution which might lead to convincing data if c primus n romeinii and n parvulum are indeed tertiary newcomer coccoliths the sediments exposed above the horizon of lichtenberg at the enci quarry and the sediments below the berg en terblijt horizon studied at curfs quarry and geulhemmerberg do belong to the np 1 biantholithus sparsus zone which means they are of early paleocene age however if these coccoliths already originate in the late maastrichtian the definition of the k t boundary by calcareous nannoflora must be revised

dynamics of outgassing and plume transport revealed by proximal unmanned aerial system uas measurements at volcan villarrica chile volcanic gas emissions are intimately linked to the dynamics of magma ascent and outgassing and on geological timescales constitute an important source of volatiles to the earth s atmosphere measurements of gas composition and flux are therefore critical to both volcano monitoring and to determining the contribution of volcanoes to global geochemical cycles however significant gaps remain in our global inventories of volcanic emissions particularly for co2 which requires proximal sampling of a concentrated plume for those volcanoes where the near vent region is hazardous or inaccessible unmanned aerial systems uas provide a robust and effective solution to proximal sampling of dense volcanic plumes in extreme volcanic environments here we present gas compositional data acquired using a gas sensor payload aboard a uas flown at volcan villarrica chile we compare uas derived gas timeseries to simultaneous crater rim multi gas data and uv camera imagery to investigate early plume evolution so2 concentrations measured in the young proximal plume exhibit periodic variations that are well correlated with the concentrations of other species by combining molar gas ratios co2 so2 1 48 1 68 h2o so2 67 75 and h2o co2 45 51 with the so2 flux 142 17 t day from uv camera images we derive co2 and h2o fluxes of 150 t day and 2850 t day respectively we observe good agreement between time averaged molar gas ratios obtained from simultaneous uas and ground based multi gas acquisitions however the uas measurements made in the young less diluted plume reveal additional short term periodic structure that reflects active degassing through discrete audible gas exhalations

the structure dynamics and chemical composition of noneruptive plumes from mount st helens 1980 1988 abstract from may 1980 to september 1988 more than 1000 fixed wing aircraft flights were made with a correlation spectrometer to measure the sulfur dioxide flux from mount st helens volcano these flights also provided valuable data on the structure and dynamics of noneruptive plumes emanating from mount st helens during 1980 and part of 1981 an infrared spectrometer was also used to measure carbon dioxide emission rates at distances up to 25 km from mount st helens plume widths can range up to 20 km or more with width thickness ratios from 3 to about 30 maximum sulfur dioxide concentrations in these plumes depend on wind speed and are typically under 5 ppm and usually 1 ppm or less close examination of the plume data reveals that the characteristics of quiescent plumes from mount st helens are strongly affected by certain meteorological conditions such as thermal and wind stratification in the troposphere as well as by the topography of the volcano

rainwater and ash leachate analysis as proxies for plume chemistry at soufriere hills volcano montserrat chloride and sulphate concentrations in rainwater and water soluble leachates from volcanic ash samples track the compositions of gas emissions at the soufriere hills volcano montserrat from 1996 to 2001 there are both systematic spatial and temporal variations in the chloride sulphate ratio expressed as the equivalent hcl so2 mass ratio in rainwater and ash leachates temporal variations reflect changes in eruption rate and eruptive style mass ratios of hcl so2 in ash leachates correspond closely with those obtained by open path fourier transform infrared op ftir spectroscopy and reflect changes in volatile emissions throughout the eruption both leachate and op ftir spectroscopic analyses show mass ratios of hcl so2 1 during dome growth and hcl so2 1 during non eruptive periods the hcl so2 mass ratios in rainwater samples from 1996 and 1997 show temporal variations that correlate with changes in extrusion rate the hcl so2 ratios in plume affected rainwater and ash leachates from june and july 2001 correlate positively with increasing rockfall energy and with increasing eruption rate prior to a dome collapse event the hcl so2 mass ratios in water soluble ash leachates and rainwater samples collected at the same time and from the same sites are linearly correlated with rainwater hcl so2 ratios systematically two to three times higher than ash leachate ratios spatial patterns of rainwater ph and hcl so2 in rainwater and ash leachates are principally influenced by the proximity of the sampling sites to the active dome and to the typical pattern of dispersion of the plume by tropospheric winds these results demonstrate that rainwater chemistry and ash leachate analysis provides a useful indicator of volcanic activity and represents a valuable supplement to volcano surveillance efforts

new radiometric ages on gneisses of the oliverian domes in new hampshire and massachusetts gneissic plutons of the oliverian domes mantled by ammonoosuc volcanics are located along the axis of the bronson hill anticlinorium from new hampshire to connecticut the contacts between the plutonic and volcanic rocks appear to be concordant on a regional scale but gneiss intrudes the volcanics in several domes available radiometric and fossil evidence suggests that the ammonoosuc volcanics have a middle ordovician age but are somewhat older than the oliverian gneisses new u pb zircon data from oliverian gneisses of six domes plot on a concordia diagram as an almost colinear array that yields an upper intercept age of about 444 m y the plotted data vary from nearly concordant to moderately discordant the degree of discordance correlating with sup 207 pb sup 206 pb ages that range from 459 to 415 m y the pattern of discordance does not relate to the uranium contents of the zircons nor to the geographic distribution of the domes if sup 207 pb sup 206 pb ages are considered individually without an assumed consanguinity of the units however they do not find particular support in geologic relationships thus they prefer the concordia intercept age of 444 8 m y for the suite as the best estimate for the time of crystallizationmore of the oliverian gneisses possibly the whitefield gneiss in the jefferson dome represents a 10 to 15 m y older unit although they are cautious about claiming such resolution with the present data less

towards quantitative environmental reconstructions from ancient non analogue microfossil assemblages ecological preferences of paleocene eocene dinoflagellates abstract we explore a novel approach towards quantification of paleo ecological signals from non analogue microfossil assemblages by quantifying relations between assemblages and high quality geochemical and sedimentological data from sedimentary archives we test this approach using one group of microfossils the organic cysts of dinoflagellates dinocysts which are widely used in shelf and open marine settings for biostratigraphy and reconstructions of past environments and environmental change similar to other microfossil groups dinocysts can be used to reconstruct environments with relatively high confidence for recent time periods as species affinities can be derived from observational and instrumental data in the absence of such data the ecology of extinct species is much less certain and as a result reconstructions in deep time are often limited to qualitative interpretations to explore if quantitative empirical relations between extinct dinocysts and high quality geochemical data can be established we study a major event of climate change the paleocene eocene thermal maximum petm 56 ma ago the petm is a particularly suitable period for this exercise as there is a multitude of large environmental perturbations associated with the transient global warming such as deoxygenation sea level rise and an accelerated hydrological cycle the synthesized published dataset exhibits better spatial and temporal coverage compared to any other period in deep time we extract empirical relations for the abundance of previously proposed paleoecological groups as a function of independent environmental proxies for example sea surface temperature and terrestrial organic matter input the results unequivocally illustrate that many dinocysts show relations to several of the reconstructed environmental variables notably we show that one genus apectodinium and an ecogroup epicystal goniodomidae required sea surface temperatures in excess of 20 c and 25 c respectively while one species florentinia reichartii was only abundant between 30 and 35 c other groups apparently favored either a limited spiniferites or high senegalinium terrestrial input to the study site relating to salinity nutrient levels or suspended sediment load i e murkiness crucially our work shows that the validation and quantification of ecological signals by independent environmental proxy data provides the opportunity to extract more quantitative information from a wide range of non analogue microfossil assemblages while this approach is not limited to any specific group of microfossils or macrofossils we stress that proper calibration datasets high quality sedimentological and geochemical proxy records are needed and should ideally have decent geographical coverage and include one or more environmental perturbations using this approach such empirical relations can be established for a wide range of microfossil groups that have highly complementary geological records which increases the value of existing data and ensures future application of microfossil based paleoecology

classification and analysis of palynodebris from the palaeocene sediments of the forties field sedimentary organic matter behaves as sedimentary particles and this study attempts to interpret its occurrence in the palaeocene sands and mudstones of the forties field of the north sea new nomenclature and classification of this palynodebris are presented and are used to make quantitative counts of the palynodebris from nearly 600 samples of known sedimentary character the new categories are further refined by objective testing of the data by principal components analysis and cluster analysis it is argued that two types of sedimentary organic matter are of particular value because they are preferentially deposited in different environments palynowafers are most commonly deposited in the submarine fan lobes and channel complexes and amorphous matter occurs mostly in the lower energy basin plain sediments

supplemental material zircon and monazite geochronology in the palmer zone of transpression south central new england usa constraints on timing of deformation high grade metamorphism and lithospheric foundering during late paleozoic oblique collision in the northern appalachian orogen analytical methods for zircon u pb and monazite th pb sims geochronology zircon u pb la icp ms geochronology data tables and supporting previous work

oxygen and carbon stable isotope records of marine vertebrates from the type maastrichtian the netherlands and northeast belgium late cretaceous abstract stable isotope analysis of marine skeletal carbonates is an important tool for palaeoenvironmental reconstructions however in mesozoic sedimentary sequences diagenetic alteration often overprints the original skeletal carbonate isotope values yet even if carbonate diagenesis did occur in such sequences the original oxygen isotope values can still be preserved in enamel or bone phosphate of vertebrate fossils here are analysed the isotope compositions of tooth enamel structural carbonate and phosphate of various late maastrichtian and early palaeocene shark and ray taxa as well as carapace bone of a late maastrichtian marine turtle allopleuron hofmanni from the type area of the maastrichtian stage in the southeast netherlands and northeast belgium no correlation is observed between 18osc and 18op suggesting diagenetic alteration of at least one fraction in comparison to modern shark teeth oxygen isotope ratios of the maastrichtian palaeocene structural carbonate 18osc are significantly lower 5 as expected from previous isotope studies of calcitic fossils from the maastrichtian type area we believe the 18osc values to have been altered by meteoric diagenesis the oxygen isotope ratios of phosphate 18op in maastrichtian palaeocene shark and ray teeth are relatively wide ranging 16 9 to 25 0 vs vsmow with median values matching data for extant shark teeth 18op suggesting retention of the in vivo 18op signal similarly the 18osc in the cheloniid turtle a hofmanni is apparently overprinted by meteoric diagenesis while the cortical compact bone of the carapace is interpreted to reflect the in vivo 18op isotope composition using a phosphate water fractionation equation for biogenic apatite and median isotope values of late maastrichtian early palaeocene shark and ray teeth a seawater temperature of 19 7 c is calculated this is in good agreement with temperatures expected for the maastrichtian of this area carbon isotope analyses 13c of structural carbonate in shark teeth have yielded isotope ratios that agree well with those of modern subtropical sharks suggesting the in vivo carbon isotope signal to have been retained a comparison of a hofmanni bone carbonate 13c values with those of extant marine turtle species suggests a hofmanni to have had a carnivorous lifestyle also a hofmanni shows 13c values that are 10 lower than the average 13c of sharks and rays more similar to sympatric mosasaurs this distribution is interpreted to be the effect of respiratory physiology on 13c fractionation

the cretaceous palaeogene boundary succession at stevns klint denmark foraminifers and stable isotope stratigraphy the cretaceous palaeogene boundary exposed at stevns klint denmark provides an important location for the investigation of the end cretaceous event in this work we have used a number of sections across the boundary including the little described expanded stratigraphic sequence at kulstirenden which is located 7 km north of hojerup where most published work is derived using stratigraphical micropalaeontological and stable isotope 18o and 13c data we have shown that there is clear evidence of shallowing in the latest maastrichtian prior to and across the cretaceous palaeogene boundary there are significant changes in sea water temperature including an important cooling event in the very latest maastrichtian the 13c record in the expanded boundary clay fish clay sequence at kulstirenden indicates a number of significant excursions of decreasing magnitude up section the evidence from the distribution of the foraminifers has been incorporated with previous work to develop a sequence stratigraphical interpretation for the succession that can be compared to other cretaceous palaeogene boundary successions in europe

the use of cyclic stratigraphic pattern of peridinioid and gonyaulacoid dinoflagellate cysts in differentiating potential thick monotonous carbonate reservoirs a possible ecostratigraphic tool under test abstract the current work used the conventional peridinioid gonyaulacoid ratio p g to devise a new concept of dinoflagellate cyst zonation called the dinoflagellate ecological zone dez which is based here on the peridinioid ecological zone pez and gonyaulacoid ecological zone gez the pez and gez were used successfully to further divide the thick monotonous carbonate succession mid cenomanian to campanian in q 72 1x well in the eastern desert of egypt into smaller ecozones pez and gez are practical and easy to use in subdividing large conventional biozones of the carbonate reservoirs into distinguishable smaller ecozones when a finer resolution is necessary on a reservoir scale for production demands this tool is suggested to be used in the hydrocarbon exploration industry with minimum knowledge of the taxonomy of the dinoflagellate cysts the proposed pez and gez are related to local ecological conditions within the basin hydrocarbon field i e can be traced out laterally in an intra basinal scale this tool can be applied to any carbonate reservoirs in any petroliferous basin worldwide moreover the p g ratio the relative abundances of the dinoflagellate cyst assemblages and other palynological parameters were used successfully to reveal the palaeodepositional settings of the identified pez and gez alternating transgressive and regressive phases were identified although a dissimilar species composition is observed in each of these ecozones environments were interchanging between the regressive marginal marine to proximal inner neritic and the transgressive distal inner to middle shelf settings three peridiniacean dinoflagellate cyst peaks were recorded the middle cenomanian subtilisphaera peak the middle coniacian isabelidinium chatangiella and manumiella peak and the middle santonian isabelidinium peak

metamorphic thermal and tectonic evolution of central new england mountain skitchewaug and big staurolite nappes reactivation of a new detailed tectonic model is presented for the acadian orogenic this fabric during thrusting is recorded in some rocks of the big belt of central new england vermont and new hampshire that staurolite nappe by rotated garnets that grew during near isothermal accounts for a wide range of petrological and structural observations loading only the sillimanite isograd crosses the fall mountain three belts are considered the eastern vermont merrimack and skitchewaug nappe boundary metamorphic breaks across the skitintervening bronson hill belts specific observations in eastern chewaug big staurolite nappe boundary at the base of the big vermont that are accounted for in the model include the following staurolite nappe and at the margin of the keene and alstead domes p t paths are clockwise with maximum pressures near the athens require post metamorphic thrusting when p t conditions were in chester and strafford domes of 8 11 kbar but with maximum the greenschist facies these observations can be explained by a pressures decreasing to 3 5 kbar at the boundary with the bronson relatively simple model involving in sequence thrusting from east to hill belt differential exhumation of the vermont domes relative to west commencing in central new hampshire at 400 410 ma the rocks in easternmost vermont is required by the recorded differences preservation of the low grade belt along the vermont new hampin maximum pressure 5 6 kbar 15 20 km and the present day shire border requires that crustal thickening in vermont was not geographical separation 7 10 km specific observations in new caused by emplacement of new hampshire nappes onto eastern hampshire that are explained include the following p t paths in vermont and that the nappes of western new hampshire had time the merrimack belt are counter clockwise with maximum pressures to cool before final juxtaposition against the low grade belt cooling of 4 5 kbar and are related to high regional heat flow and heat ages constrain this final juxtaposition to have occurred in the transfer by early acadian plutons p t paths in the bronson hill carboniferous suggesting that the acadian was a prolonged event belt are intimately associated with structural position an early spanning as much as 100 myr contact metamorphism is evidenced in the skitchewaug and fall mountain nappes near contacts with the early acadian bethlehem gneiss 400 410 ma peak metamorphic temperature rises upwards in the nappe sequence an inverted metamorphic sequence

dinoflagellate cysts from the upper campanian upper cretaceous of hornby island british columbia canada with implications for nanaimo group biostratigraphy and paleoenvironmental reconstructions abstract thirty mudstone samples from coastal exposures of the northumberland formation on hornby island british columbia canada yielded diverse dinoflagellate cyst and terrestrial sporomorph assemblages a late campanian age for the formation has been well defined through magnetostratigraphy macrofossil biostratigraphy and geochemical studies of the hornby island section dinoflagellate cyst taxa corresponding to 61 genera are exceptionally well preserved and include specimens referable to at least 68 formally established species the earliest occurrences of canninginopsis maastrichtiensis druggidium cf discretum phanerodinium belgicum renidinium cf vitilaire senegalinium simplex spiniferella cornuta and xenicodinium delicatum sensu slimani et al are reported along with the most recent occurrence of senoniasphaera protrusa extending their stratigraphic ranges into the upper campanian the palynomorph assemblages support a late campanian age two dinoflagellate cyst ecozones are recognized ecozone 1 and ecozone 2 assemblages suggest sediment deposition in an inner shelf environment with moderate to high nutrient input and primary productivity

recognition of cyclic and non cyclic environmental changes in the mediterranean pliocene a palynological approach the interval between 2 8 and 2 3 ma b p from the south italian singa section has been investigated for its dinoflagellate cyst and sporomorph contents in order to facilitate palaeoenvironmental interpretation the following curves are derived from the data the ratios sporomorphs dinoflagellate cysts protoperidinioid gonyaulacoid dinoflagellate cysts warm cold water indicating dinoflagellate cysts inner neritic oceanic dinoflagellate cysts outer neritic oceanic dinoflagellate cysts and the reworked dinoflagellate cysts per gram of sediment furthermore the already available 18o curve has been used calibration of changes in the sporomorph dinoflagellate ratio against the computed astronomical insolation curve leads to an improved age assessment for the section frequency analysis on the curves shows the 23 41 and 100 ka frequency components to be most important phase and amplitude differences between the filtered 23 41 and 100 ka frequency components are used for environmental interpretation the 23 ka frequency band is best explained by changes in runoff induced transport the 41 ka frequency components are classified in a group with short response time to orbital forcing and a group with longer response time those signals having a short response time are attributed to local precipitation induced changes in runoff those signals having a longer response time are mainly attributed to changes in global temperature and to a lesser extent to changes in global ice volume finally longer term cyclic and non cyclic changes are mainly attributed to temperature and sea level variation

a mesozoic time scale we present an integrated geomagnetic polarity and stratigraphic time scale for the triassic jurassic and cretaceous periods of the mesozoic era with age estimates and uncertainty limits for stage boundaries the time scale uses a suite of 324 radiomenc dates including high resolution 40 ar 39 ar age estimates this framework involves the observed ties between 1 radiometric dates biozones and stage boundaries and 2 between biozones and magnetic reversals on the seafloor and in sediments interpolation techniques include maximum likelihood estimation smoothing cubic spline fitting and magnetochronology

the cretaceous paleogene boundary foraminifera sea grasses sea level change and sequence stratigraphy abstract the tsunami generated by the chicxulub impact eroded the uppermost cretaceous surface of the gulf coast region u s a forming a distinctive topography that was previously interpreted as a sequence boundary at more distal sites such as stevns klint denmark there appears to be no sequence boundary at the cretaceous paleogene boundary but there is one within the uppermost maastrichtian between the sigerslev and hojerup members and another in the lowermost paleocene top of zone p1a both of these surfaces are identified by distinctive phosphatized and incipient hardgrounds the changes in sea level involved in the generation of uppermost cretaceous sequences are thought to have been minimal as in the gulpen and maastricht formations of the maastricht area netherlands the presence of sea grasses and their associated foraminifera would indicate that the chalk sea floor remained within the range of water depth that would allow photosynthesis

ftir remote sensing of fractional magma degassing at mount etna sicily abstract the chemical composition of volcanic gas emissions from each of the four summit craters of mount etna was measured remotely in may 2001 using a fourier transform infrared ftir spectrometer operated on the upper flanks of the volcano the results reveal constant hci hf ratio but distinct so2 hc1 and so2 hf ratios in the emitted gases which in the light of melt inclusion data for etna basalts can be interpreted in terms of escape of gases from partially and variably degassed magma at different depths beneath the summit gases released from the three main summit craters bocca nuova voragine and northeast had an identical composition controlled by bulk degassing of a single magma body that had previously lost c 25 0 of its original sulphur the similar gas composition at all three main craters suggests that these are connected to a central conduit system that branches at relatively shallow depth measurements of the bulk volcanic plume on the same day c 7 km downwind show that degassing from these craters dominated the total gas output of the volcano and that no significant chemical evolution occurred within the plume over a time scale of c 12 min weaker gas emissions from the southeast crater were comparatively depleted in so2 so2 hc1 and so2 hf ratios a factor of two lower implying that this crater is fed either by a separate conduit or by a branch of the central conduit whose geometry favours solubility controlled volatile fractionation still lower so2 hc1 and so2 hf ratios measured for residual degassing of a lava flow erupted from the southeast crater verify the lower solubility and earlier escape of sulphur compared to halogens at etna fractional magma degassing is also implied by strong chemical contrasts between the bulk volcanic plume and fissure gas emissions measured during the july august 2001 flank eruption these results highlight the ability of ftir spectrometry to detect fine spatial and temporal variations in magma degassing processes and thereby constrain models of shallow plumbing systems introduction magmas contain dissolved volatiles h20 co2 s c1 f etc with differing solubility behaviom which gradually reach a saturation pressure and exsolve into a separate gas phase bubbles during magma ascent and crystallization this volatile phase plays a central role in magmatic and volcanic processes e g anderson 1975 and its chemical composition changes from depth to the surface according to the pressure controlled solubility behaviour of each volatile species but also as a function of the dynamics of magma supply and ascent sparks 2003 this volume in fact gas bubbles may rise with either the same velocity as surrounding magma allowing continuous gas melt equilibration and single step bulk gas emission at the surface or with a higher velocity thereby reaching the surface independently of the parental magma batch e g sparks 1978 vergniolle jaupart 1986 in the latter case chemical equilibrium between gas and magma may be inhibited sustained high gas fluxes in excess of lava production on basaltic volcanoes such as etna and stromboli typically require a separated bubble flow and in the long term convective renewal of volatile rich magma from depth francis

dinoflagellate biostratigraphy and sequence stratigraphy of the type maastrichtian upper cretaceous enci quarry the netherlands abstract the upper maastrichtian strata in enci quarry contain rich assemblages of marine palynomorphs especially dinoflagellate cysts a quantitative study shows that a marked change from dinoflagellate dominated assemblages to assemblages dominated by the acritarch genus paralecaniella occurs at the base of the lanaye member indicating a change from open marine to marginal marine conditions a sequence stratigraphic breakdown into systems tracts based on an interpretation of the changes in the palynological assemblages and lithology suggests the presence of parts of four sedimentary cycles in the enci section three of the cycles may be correlated with the third order cycles uza 4 5 ta 1 1 and ta 1 2 of haq et al 1988 the fourth cycle is probably of higher order three dinoflagellate cysts are new laciniadinium aquiloniforme schioler et al sp nov leberidocysta verrucosa schioler et al sp nov and pulchrasphaera minuscula schioler et al gen et sp nov the description of rottnestia wetzelii is emended and the new combination cribroperidinium wilsonii slimani schioler et al comb nov is proposed the triblastula utinensis zone isabelidinium cooksoniae zone and the palynodinium grallator zone with its two subzones tanyosphaeridium magdalium subzone and thalassiphora pelagica subzone can be recognized in the enci section

depletion rates of sulfur dioxide in tropospheric volcanic plumes the tropospheric sulfur cycle has been closely studied from the standpoint of anthropogenic emissions but less so with respect to volcanic sources we document here evidence for wide variation in lifetimes of volcanic so2 in the troposphere at one extreme our observations of the plume associated with the lavadome eruption of soufriere hills volcano montserrat suggest loss of gaseous so2 at rates exceeding 10 3 s 1 while this efficent so2 depletion reflects unusual environmental factors published measurements for mount etna s plume approach these rapid rates in such cases source strengths of so2 must significantly exceed apparent fluxes measured several kilometres downwind this implies that meteorological and geographic factors as well as volcanic degassing rates should be considered in the interpretation of fluxes of so2 measured beyond source vents with ramifications for volcano monitoring and eruption prediction furthermore since most calculations of global volcanic fluxes of sulfur and other species to the troposphere are based on extrapolation of so2 flux data they may underestimate true source strengths finally we consider that fast sulfur chemistry may also prevail in convecting eruption columns resulting in partial tropospheric scrubbing of sulfur from stratosphere bound plumes

a rare garnet tourmaline sillimanite biotite ilmenite quartz assemblage from the granulite facies region of south central massachusetts a rare lithology consisting of garnet tourmaline sillimanite biotite ilmenite quartz has been found within the granulite facies region of south central massachusetts the homogeneous ti rich oxy dravitic tourmaline x mg mg mg fe 0 72 0 77 falls into the alkali group and is similar in composition to lower grade tourmaline found in corresponding metapelitic rocks in maine charge balancing calculations and binary diagrams suggest that like biotite in the region tourmaline has undergone deprotonation by means of the exchange vectors alor 1 oh 1 and tio 2 r 1 oh 2 where r represents fe mg the restriction of a concordant tourmaline rich horizon in otherwise tourmaline free rocks of this granulite facies region suggests that either 1 b released during prograde fluid absent dehydration reactions of muscovite and biotite was locally available in a fluid phase or melt for later crystallization near the peak of granulite facies metamorphism along pathways that provided a conduit for fluid migration or 2 that this is simply a b rich compositional horizon tourmalinite that survived anatexis and granulite facies metamorphism and that records the incipient conditions of tourmaline breakdown and subsequent recrystallization near or post peak metamorphism

plume chemistry provides insights into mechanisms of sulfur and halogen degassing in basaltic volcanoes abstract this paper deals with sulfur chlorine and fluorine abundances in the eruptive volcanic plume of the huge october 2002 january 2003 eruption of mount etna aiming at relating the relevant compositional variations observed throughout with changes in eruption dynamics and degassing mechanisms the recurrent sampling of plume acidic volatiles by filter pack methodology revealed that during the study period s cl and cl f ratios ranged from 0 1 6 8 and 0 9 5 6 respectively plume s cl ratios increased by a factor of 10 as volcanic activity drifted from paroxysmal lava fountaining mid and late november to passive degassing and minor effusion early january and then decreased to the low values s cl 0 1 typical of the final stages of the eruption parallel variations in chlorine to fluorine ratios were also observed a theoretical model is proposed for quantitative interpretation of these changes in plume composition the model calculates the composition of a volatile phase exsolving from an ascending etna magma based on knowledge of solubilities and abundances in the undegassed melt of sulfur and halogens t m gerlach eos 72 1991 249 254 255 according to this model degassing of etnean basaltic melt at high pressures and depths 100 mpa 3 km is likely to release a co2 h2o rich vapor phase with s cl molar ratios 1 extensive sulfur and chlorine degassing from the melt would take place at shallower depth p

scales of equilibrium and disequilibrium during cleavage formation in chlorite and biotite grade phyllites se vermont detailed electron microprobe analyses of phyllosilicates in crenulated phyllites from south eastern vermont show that grain scale zoning is common and sympathetic zoning in adjacent minerals is nearly universal we interpret this to reflect a pressure solution mechanism for cleavage development where precipitation from a very small fluid reservoir fractionated that fluid multiple analyses along single muscovite biotite and chlorite grains 30 200 m in length show zoning patterns indicating tschermakitic substitutions in muscovite and both tschermakitic and di trioctahedral substitutions in biotite and chlorite using cross cutting relationships and mineral chemistry it is shown that these patterns persist in cleavages produced at metamorphic conditions of chlorite grade chlorite grade overprinted by biotite grade and biotite grade zoning patterns are comparable in all three settings requiring a similar cleavage forming mechanism independent of metamorphic grade moreover the use of 40ar 39ar geochronology demonstrates this is true regardless of age furthermore samples with chlorite grade cleavages overprinted by biotite porphyroblasts suggest the closure temperatures for the diffusion of al si mg and fe ions are greater than the temperature of the biotite isograd 400 c parallel and smoothly fanning tie lines produced by coexisting muscovite chlorite and muscovite biotite pairs on compositional diagrams demonstrate effectively instantaneous chemical equilibrium and probably indicate simultaneous crystallization these results do not support theories suggesting cleavages form in fluid dominated systems if crenulation cleavages formed in systems in which the chemical potentials of all major components are fixed by an external reservoir then the compositions of individual grains defining these cleavages would be uniform on the contrary the fine scale chemical zoning observed probably reflects a grain scale process consistent with a pressure solution mechanism in which the aqueous activities of major components are defined by local dissolution and precipitation thus the role of fluids was probably limited to one of catalysing pressure solution and fluids apparently did not drive cleavage development

organic facies as a tool for recording eustatic variations in marine fine grained carbonates example of the berriasian stratotype at berrias ardeche se france abstract sediments of the berriasian stratotype in southeastern france consist of marine fine grained carbonates deposited on an outer shelf at the western edge of the vocontian trough the limestones are monotonous but display some erosional surfaces and a condensed interval they are well dated by ammonites and calpionellids except at the base of the section where the boundary with the tithonian is not clearly established despite their very high carbonate content the limestones yielded enough organic residue to allow a study of palynofacies variations in time organic content consists of two fractions one is made of terrestrial components represented essentially by humic fragments of the inertinite and vitrinite maceral groups and accessorily by pollen and spores the other comprises marine components essentially dinocysts and accessorily foraminiferal linings absence of amorphous organic matter and the oxidized nature of dinocysts observable in uv light indicate that aerobic conditions prevailed throughout the berriasian probably associated with a low sedimentation rate the following qualitative and quantitative criteria indicating distal proximal trends were used to convert palynofacies observations into a tentative palaeoenvironmental curve ratio of continental to marine organic constituents diversity of dinocysts degree of biodegradation affecting humic fragments proportion of blade shaped inertinite and finally size sorting and rounding of equidimensional inertinite particles the palaeoenvironmental curve derived from organic matter shows oscillations between more proximal i e shallower water and more distal i e deeper water conditions these variations combined with biostratigraphic information and the few significant sedimentological data can be interpreted in terms of sequence stratigraphy and compared with the global sea level curve published earlier the fairly good correlation between this global curve and that established from palynofacies demonstrates the influence of relative sea level on the organic facies of the berriasian carbonates and the contribution of palynofacies studies to sequence stratigraphy

petrology of the regional sillimanite zone west central new hampshire u s a with implications for the development of inverted isograds abstracr sillimanite from the regional sillimanite zone in west central new hampshire is fibrolitic and overprints f2 folds nappe stage of earlier mica foliation regional sillimanite zone samples show no evidence for earlier staurolite parageneses despite the fact that staurolite is abundant at lower grade because sillimanite was produced directly from garnet chlorite by the prograde heating reaction garnet chlorite muscovite quartz sillimanite biotite h20 the pressure at which this reaction occurs is sensitive to the mno and cao contents of garnet and phase equilibrium arguments reveal that at the regional pressures of west central new hampshire 2 4 kbar staurolite parageneses are only possible in rocks with low mno cao the inferred p t path is counterclockwise with nearly isobaric initial heating at 2 kbar followed by loading t heating to a peak metamorphic temperature of 600 t 25 c at 4 kbar followed by nearly isobaric cooling garnets were compositionally homogenized near the metamorphic peak but subsequent cooling was rapid 100 c m y these data argue against the folded isotherm model of chamberlain 1986 instead the present distribution of metamorphic grades is interpreted to be the result of regional stacking of high grade thrust sheets on lower grade rocks followed by depression of high grade rocks to lower structural levels

les debits de co2 et de so2 volcaniques dans l atmosphere la contribution des volcans a l atmosphere est reevaluee a 5 107 tonnes de so2 et 108 tonnes de co2 par an

h2s fluxes from mt etna stromboli and vulcano italy and implications for the sulfur budget at volcanoes abstract we present here new measurements of sulfur dioxide and hydrogen sulfide emissions from vulcano etna and stromboli italy made by direct sampling at vents and by filter pack and ultraviolet spectroscopy in downwind plumes measurements at the f0 and fa fumaroles on vulcano yielded so 2 h 2 s molar ratios of 0 38 and 1 4 respectively from which we estimate an h 2 s flux of 6 to 9 t d 1 for the summit crater for mt etna and stromboli we found so 2 h 2 s molar ratios of 20 and 15 respectively which combined with so 2 flux measurements suggest h 2 s emission rates of 50 to 113 t d 1 and 4 to 8 t d 1 respectively we observe that source and plume so 2 h 2 s ratios at vulcano are similar suggesting that hydrogen sulfide is essentially inert on timescales of seconds to minutes this finding has important implications for estimates of volcanic total sulfur budget at volcanoes since most existing measurements do not account for h 2 s emission

so2 flux measurements at mount etna sicily since 1987 over 220 measurements of the so2 flux at mount etna have been carried out using a correlation spectrometer cospec with different measuring techniques mainly with cospec mounted on a ground based vehicle this paper reports and analyzes the data obtained between october 1987 and december 1991 during this period three distinct time intervals characterized by particular so2 emission patterns were identified the first interval a showed a mean so2 flux of 5500 t d associated with relatively quiet summit crater eruptive activity the second interval b included two eruptive periods september october 1989 and january february 1990 associated with high fluxes reaching 10 000 25 000 t d the third interval c started in concert with a regional earthquake december 13 1990 and showed first a decrease and then an increase of so2 emissions before the onset of the major 1991 1993 flank eruption analysis of the data reveals a cyclic pattern to the so2 emissions over prolonged periods a nearly constant supply of so2 from the volcano s main feeder system especially evident in the long term a two to fivefold increase above mean flux values from 10 000 to 25 000 t d when occurring with paroxysmal eruptive activity and minimal flux values 1000 t d about 1 month prior to important eruptive events

a high resolution north sea eocene dinocyst zonation abundant dinoflagellate cysts dinocysts from eocene strata of the north sea exhibit a consistent succession of events based on the analysis of 120 wells from quadrant 3 in the north to quadrants 21 and 22 in the south these events have a constant relationship with stratigraphic sequences and subsequences throughout the area eight eocene dinocyst zones and 23 subzones and the uppermost palaeocene apectodinium augustum biozone are defined by last occurrence or abundance events the north sea dinocyst succession is similar to that in denmark northwest germany belgium the netherlands and southern england permitting correlation with calcareous nannoplankton zones for sections in these areas and hence allowing correlation of north sea stratigraphy with northwest european and worldwide events

in situ measurements of tropospheric volcanic plumes in ecuador and colombia during tc4 a nasa dc 8 research aircraft penetrated tropospheric gas and aerosol plumes sourced from active volcanoes in ecuador and colombia during the tropical composition cloud and climate coupling tc 4 mission in july august 2007 the likely source volcanoes were tungurahua ecuador and nevado del huila colombia the tc 4 data provide rare insight into the chemistry of volcanic plumes in the tropical troposphere and permit a comparison of so 2 column amounts measured by the ozone monitoring instrument omi on the aura satellite with in situ so 2 measurements elevated concentrations of so 2 sulfate aerosol and particles were measured by dc 8 instrumentation in volcanic outflow at altitudes of 3 6 km estimated plume ages range from 2 h at huila to 22 48 h downwind of ecuador the plumes contained sulfate rich accumulation mode particles that were variably neutralized and often highly acidic a significant fraction of supermicron volcanic ash was evident in one plume in plume o 3 concentrations were 70 80 of ambient levels downwind of ecuador but data are insufficient to ascribe this to o 3 depletion via reactive halogen chemistry the tc 4 data record rapid cloud processing of the huila volcanic plume involving aqueous phase oxidation of so 2 by h 2o 2 but overall the data suggest average in plume so 2 to sulfate conversion rates of 1 2 h 1 so 2 column amounts measured in the tungurahua plume 0 1 0 2 dobson units are commensurate with average so 2 columns retrieved from omi measurements in the volcanic outflow region in july 2007 the tc 4 data set provides further evidence of the impact of volcanic emissions on tropospheric acidity and oxidizing capacity

dinoflagellate species and organic facies evidence of marine transgression and regression in the atlantic coastal plain abstract palynological evidence is used to date and interpret depositional environments of sediments of campanian maestrichtian and early danian ages cored in three wells from south carolina and georgia the evidence is usefil for distinguishing environments which lithofacies evidence indicates a range from nonmarine to coastal to inner neritic shallow shelf numerous dinoflagellate species and an organic facies defined abundant amoprphous debris amorphous debris facies distinguish shallow shelf sediments deposited during marine transgression the nearshore amorphous debris facies of late campanian age consists of heterogenous assemblages dominated by palaeohystrichophora infusorioides deflandre or hystrichosphaerina varians may the farther offshore amorphous debris facies of late early maestrichtian to late maestrichtian age consists of heterogenous assemblages dominated by glaphyrocysta retiintexta cookson and or areoligera medusettiformis wetzel the larger number of dinoflagellate species in the offshore facies represents the maximum transgression detected in the investigated interval a multiple occurrence datum defined by the combination of first appearance klast appearances and sole occurrence of dinoflagellate species at the base of each interval distinguished by the amorphous debris facies provides the first evidence of marine transgression relatively small organic residues consisting of intertinite and few or no palynomorphs define the inertinite facies in nonmarine deltaic and in coastal lagoonal tidal flat interdistributary bary sediments dinocyt s are absent in the nonmarine sediments and are represented by few species and few specimens in the coastal inertinite faceis a third organic facies vascular tissue facies is defined by the abundance of land plant tissue sporomorph species including those of the normapolles pollen group and of pteridophyte spores comprise a large proportion of the total palynomorph flora in the inertinite and vascular tissue facies the vascular tissue facies occurs in the proximal prodelta and nearshore shallow shelf lithofacies of early maestrichtian age baed in the sequence of organuic facies dinoflagellate species abundance and lithofacies in the investigated wells the nonmarine and coastal inertinite facies was first deposited and was followed during the late campanian by a marine trangression when the nearshore amorphous debris facies was deposited this was followed in the early maestrichtian by the influx of terrigenous organic matter vascular tissue facies in response to deltaic progradation on the shallow shelf a marine regression occured towards the close of the early maestrichtian emplacing the coastal inertinite facies the major marine transgression occured near the end of the early maestrichtian developing a farther offshore amorphous debris facies on an expanded continental shelf which persisted through the late maestrichtian the inertinite facies returned during marine regression in the approximate position of the maestrichtian danian boudnary

palaeoecology and palaeoenvironments of the lower palaeogene succession offshore west greenland the microfossil and palynofloral assemblages of the paleocene to middle eocene succession offshore west greenland have been investigated several taxa which are believed to reflect specific palaeoenvironments were selected and their relative abundances measured subsequently an interpretation of the changing depositional settings in the hellefisk 1 ikermiut 1 kang miut 1 nukik 1 and nukik 2 boreholes through the lower palaeogene has been made

probing the depths of oliverian magmas implications for paleozoic tectonics in the northeastern united states oliverian magma series gneisses 442 454 ma in the cores of domes in southwestern new hampshire have an igneous mineralogy that crystallized at pressures p of 9 11 kbar and temperatures t of 650 775 c whereas the cover ammonoosuc volcanics has the same formation age 453 2 ma yet is clearly extrusive a significant crustal section 30 km thick must have originally separated the two units a recognition that demands tectonic reinterpretation of this classic orogen acadian age ca 400 ma metamorphism at p 4 6 kbar t 625 c is well documented in the cover but the absence of expected diffusional reequilibration in oliverian garnets indicates that they never exceeded 550 c after formation juxtaposition of the oliverian magma series gneisses and their cover must have occurred after the cover had cooled below 550 c and was likely via either neo acadian or alleghanian thrusting

palynofacies analysis and organic walled dinoflagellate cysts in late holocene sediments from igaliku fjord south greenland this study characterizes late holocene past 3300 years variations in organic matter deposition in the outer part of igaliku fjord south greenland and uses this information to assess palaeohydrographic conditions except for two all residues were characterized by abundant organic matter with amorphous material dominating the late holocene sediments in the deeper parts of the outer igaliku fjord have generally been deposited under anoxic to suboxic conditions with relatively low terrestrial freshwater influx the organic walled dinoflagellate cyst assemblages suggest the continuous presence of water masses derived from the east greenland current while changes in sea surface temperature during the last 3300 years have also been interpreted terrestrial influx was reflected by the continuous occurrence of leaf tissue which increased in abundance in sediments younger than ad 960 pseudo amorphous phytoclasts occurred in sediments older than ad 770 and sporomorphs were rare throughout acritarchs and o

dip domain method applied to the mesozoic connecticut valley rift basins this paper presents a new approach to structural analysis of u s east coast mesozoic basins a contoured compilation of numerical values of dip data for the connecticut valley rift basins reveals distinct domains related to their broader tectonic development additional more standard geologic constraints are then used to interpret the dip domain patterns most of the tilt deformation involved and hence postdated early jurassic basaltic flow units and overlying jurassic thick alluvial deposits normal drag characterizes the attitude of mesozoic strata along the western border fault of the main hartford basin whereas reverse drag is common along its larger listric eastern border fault strata within the basin mostly along its eastern margin include several subgrabens and or strongly tilted zones associated with early subbasins marked by local changes in strike of the early border fault the meriden cross graben may be a similar structure that extended much farther southwestward across the basin within the hartford basin linear domains of steeper dips are interpreted as surface expressions of the edges of a 5 to 15 km wide late stage central graben that trends n15 e diagonally across the basin possibly a reflection of very late strike slip stress systems

dinoflagellate based sea surface temperature reconstructions across the cretaceous tertiary boundary abstract quantitative analysis of organic walled dinoflagellate cyst dinocyst assemblages from closely spaced samples across the cretaceous tertiary boundary ktb at el kef nw tunisia caravaca se spain and stevns klint e denmark allows for reconstructions of sea surface temperature sst trends the combined dinocyst based sst curves indicate relatively stable warm conditions during the latest maastrichtian in contrast to strongly fluctuating and on average cooler conditions during the earliest danian in detail the results indicate cooling across the ktb immediately followed by an interval of pronounced warming the latter recorded in all studied sections two more cooling pulses may be recognized in the overlying interval followed by a gradual return to stable relatively warm conditions our data furthermore show that these ktb related climatic changes invoked distinct migration among organic walled cyst producing dinoflagellates a group not pushed to extinction at the ktb recordable in both hemispheres recent models predict periods varying between several months to 8 13 yr of global cooling impact winter and reduced solar transmission as a direct result of the chicxulub ktb impact followed by relatively long term excess co 2 related global warming our results are in line with such models but suggest that the impact related cooling phase may have lasted longer and that marked climatic instability continued to some 100 000 yrs following the ktb event s

palynofacies and sea level changes in the middle coniacian late campanian late cretaceous of the east coast basin new zealand abstract a palynofacies analysis of four sections through the paton and herring formations of the east coast basin in southern marlborough indicates that the two formations were deposited on the inner to mid shelf in a marine environment with conspicuous input of plant material from adjacent land area the paton formation was deposited on the inner to mid shelf under oxic conditions and in proximity to a river delta possibly in a deltafront setting its lower part is clearly less marine than its upper part pointing to an overall deepening trend with time the deposition of the herring formation took place farther offshore on the mid shelf in a mud dominated environment under poorly oxygenated conditions at the sediment water interface following a landward shift of shoreline a stratigraphic analysis of changes in palynofacies and lithology through the four sections allows a breakdown of the succession into seven depositional sequences separated by unconformities or their correlative conformities a regional sea level curve for the middle coniacian upper campanian in the east coast basin is proposed on the basis of the inferred sequences and chronostratigraphic control from dinoflagellate biostratigraphy the sea level cycles thus inferred for the east coast basin show a poor correlation with the re scaled haq cycle chart suggesting that regional tectonics rather than eustasi controlled the east coast basin sequences

latest cretaceous climatic and environmental change in the south atlantic region latest maastrichtian climate change caused by deccan volcanism has been invoked as a cause of mass extinction at the cretaceous paleogene k pg boundary 66 0 ma yet late maastrichtian climate and ecological changes are poorly documented in particular on the southern hemisphere here we present upper maastrichtian lower danian climate and biotic records from the bajada del jaguel bj shelf site neuquen basin argentina employing the tex86 paleothermometer marine palynology dinoflagellate cysts and micropaleontology foraminifera these records are correlated to the astronomically tuned ocean drilling program site 1262 walvis ridge collectively we use these records to assess climatic and ecological effects of deccan volcanism in the southern atlantic region both the tex86 based sea surface temperature sst record at bj and the bulk carbonate 18o based sst record of site 1262 show a latest maastrichtian warming of 2 5 4 c at 450 to 150 kyr before the k pg boundary coinciding with the a large deccan outpouring phase benthic foraminiferal and dinocyst assemblage changes indicate that this warming resulted in enhanced runoff and stratification of the water column likely resulting from more humid climate conditions in the neuquen basin these climate conditions could have been caused by an expanding and strengthening thermal low over the south american continent biotic changes in response to late maastrichtian environmental changes are rather limited when compared to the major turnovers observed at many k pg boundary sites worldwide this suggests that environmental perturbations during the latest maastrichtian warming event were less severe than those following the k pg boundary impact

constraining the sulfur dioxide degassing flux from turrialba volcano costa rica using unmanned aerial system measurements abstract observed sulfur dioxide so 2 mixing ratios onboard unmanned aerial systems uas during march 11 13 2013 are used to constrain the three day averaged so 2 degassing flux from turrialba volcano within a bayesian inverse modeling framework a mesoscale model coupled with lagrangian stochastic particle backward trajectories is used to quantify the source receptor relationships at very high spatial resolutions i e 2 variations when using a first order closure non local planetary boundary layer pbl scheme the optimized so 2 degassing fluxes vary from 0 59 0 37 to 0 83 0 33 kt d 1 depending on the pbl scheme used these fluxes are in good agreement with ground based gas flux measurements and correspond to corrective scale factors of 8 12 to the posteruptive so 2 degassing rate in the aerocom emission inventory the maximum a posteriori solution for the so 2 flux is highly sensitive to the specification of prior and observational errors and relatively insensitive to the so 2 loss term and temporal averaging of observations our results indicate relatively low degassing activity but sustained sulfur emissions from turrialba volcano to the troposphere during march 2013 this study demonstrates the utility of low cost small uas platforms for volcanic gas composition and flux analysis

environmental change across the paleocene eocene transition from eastern new zealand a marine palynological approach abstract recent improvements in the resolution and calibration of dinoflagellate cyst dinocyst bioevents across the paleocene eocene p e transition in new zealand allow better understanding of the relation between dinocyst variations and environmental change in southern mid high latitudes during this greenhouse climate combining information from land spore pollen assemblages with coeval dinocyst records allows evaluation of plant changes in a marine based timeframe palynological associations at tawanui and moeraki hampden eastern new zealand fluctuate across the p e transition and local palynological phases are recognized the onset of major fluctuations in dinocyst assemblages coincide with the intense warmth and excess carbon of the initial eocene thermal maximum ietm changes in sea surface temperature sst appear to have been the main environmental factor that affected dinoflagellates short lived intervals of higher ssts suggested by a high relative abundance of the apectodinium complex are seen during the ietm and lower eocene abundant cysts of probable heterotrophic dinoflagellates suggest surface waters remained relatively eutrophic for up to 0 5 myr after the onset of the ietm perhaps in response to enhanced terrigenous input related to changes in the character and pattern of continental weathering in contrast to dinocysts spore pollen assemblages suggest plant communities remained rather stable across the p e transition vegetation was dominated by a mesothermal conifer dominated multistratal rainforest and low latitude nypa mangroves were established by the uppermost paleocene plants in this region show no clear response to the ietm and the predominant vegetation change may have occurred at least 1 5 myr later characterized by an increase in mesothermal megathermal angiosperm plants

mutual exsolution in hornblende and cummingtonite compositions lamellar orientations and exsolution temperatures exsolved pairs of hornblende and cummingtonite from two localities in southern new england u s a have been studied using transmission electron microscopy tem to measure the crystallographic orientation of the exsolution lamellae both the cummingtonite and the hornblende show multiple generations or stages of exsolution electron microprobe analyses gave compositions of the pre exsolved averages and the coarsest exsolved amphiboles in amphiboles two orientations of lamellae are usually present and nearly parallel to loa and lot of the host the observed lamellar orientations are consistent with orientations predicted by the optimal phase boundary opb theory and are a function of small differences in a c and 3of the host and exsolved amphiboles a ahost alamella 3 3host 3lamella and c chost clamella because these lattice parameters vary with t and composition the precise orientations of the lamellae are controlled by these variables the widths of determined exsolution lamellae varied from microscopic micrometer size to submicroscopic nanometer size the tem images show in some cases multiple generations of lamellae with lamellar orientations near lot differing up to 4 1 whereas orientations near loa differed up to 4 for two pairs of coexisting amphiboles the t dependence of the lattice parameters from 25 to 600 c was measured using a guinier camera the opb calculations indicate that for all the samples the different lamellar generations formed between about 780 and 300 c t80 c on the basis of maximum errors of the lattice parameter determinations lamellae of the same generation all showed nearly the same width exsolution temperatures could not be derived from the 100 lamellae because relatively small variations in c which controls exact orientation of the 100 lamellae could not be measured accurately enough

progressive evolution from uplift to orogen parallel transport in a late acadian upper amphibolite to granulite facies shear zone south central massachusetts fabrics within a 1 km wide shear zone along the eastern margin of the bronson hill anticlinorium in central massachusetts provide important information on the regional tectonic development during the devonian acadian orogeny two distinct mineral lineations observed within the zone are each defined by alignment of coarse sillimanite needles and elongated quartz and feldspar grains and aggregates both lineations are associated with shearing and development of mylonitic fabrics the character of the two lineations and related fabrics differs mainly in orientation and in the relationship of each lineation to the local orientation of quartz c axis fabrics the interpreted earlier lineation has a steep west plunge and the later lineation has a shallow plunge and north south to southwest trend parallel to the regional trend of the orogen extensive dynamic recrystallization of feldspar the possible activity of prism slip in quartz and the mineral assemblages in apparent equilibrium during deformation suggest that both lineations probably formed under upper amphibolite facies conditions just after the thermal peak of acadian metamorphism a progressive change between the two deformation fabrics is suggested by evidence of overlap between the two by their striking similarity in style and metamorphic conditions of formation and by the similarity in orientation of their bulk strain axes with a change only in the transport direction between them kinematic indicators associated with each phase of lineation development are consistent throughout the shear zone the earlier phase has a west side up sense of shear and the later phase indicates west side north movement these phases are correlated with the regional backfold and dome stages of acadian deformation the kinematics and relationships between them suggest a revised tectonic model for the later part of the acadian orogeny and for development of orogen parallel lineations in this region in this model uplift and thickening of basement gneisses in the bronson hill anticlinorium during the backfold stage was impeded by gravitational instability in a thermally weakened crust this led to a change from subvertical to subhorizontal extension east west acadian shortening was still in progress constraining this extension to a north south direction parallel to the trend of the orogen

the kearsarge central maine synclinorium of southeastern new hampshire and southwestern maine stratigraphic and structural relations of an inverted section

sulfur emissions from mt etna in the course of three measuring trips to the mt etna volcano sicily field measurements and measurements by aircraft were carried out in the plume of the volcano to determine the concentration distributions and emission rates for the sulfur compounds h2s so2 and so42 furthermore the removal of h2s and so2 and the production of so42 in the dispersing plume were investigated the dispersion of the plume was studied by simultaneous tracer measurements of the co2 concentration h2s was additionally measured at the crater rims of stromboli and vulcano the sulfur source strength of mt etna was considerably dependent on the activity phase which was post eruptive and pre eruptive respectively the emission rates were found to vary between 142 1600 t so2 d 1 10 t h2s d and 182 232 t so42 d oxidation rates of 1 7 5 0 10 4 s 1 for so2 and 2 1 10 4 s 1 for h2s could be determined by the application of two different theoretical models which are described in detail

reaction softening by dissolution precipitation creep in a retrograde greenschist facies ductile shear zone new hampshire usa we describe strain localization by a mixed process of reaction and microstructural softening in a lower greenschist facies ductile fault zone that transposes and replaces middle to upper amphibolite facies fabrics and mineral assemblages in the host littleton schist near claremont new hampshire here na poor muscovite and chlorite progressively replace first staurolite then garnet and finally biotite porphyroblasts as the core of the fault zone in approached across the transect higher grade fabric forming na rich muscovite is also progressively replaced by fabric forming na poor muscovite the mineralogy of the new phyllonitic fault rock produced is dominated by na poor muscovite and chlorite together with late albite porphyroblasts the replacement of the amphibolite facies porphyroblasts by muscovite and chlorite is pseudomorphic in some samples and shows that the chemical metastability of the porphyroblasts is sufficient to drive replacement in contrast element mapping shows that fabric forming na rich muscovite is selectively replaced at high strain microstructural sites indicating that strain energy played an important role in activating the dissolution of the compositionally metastable muscovite the replacement of strong high grade porphyroblasts by weaker na poor muscovite and chlorite constitutes reaction softening the crystallization of parallel and contiguous mica in the retrograde foliation at the expense of the earlier and locally crenulated na rich muscovite defined foliation destroys not only the metastable high grade mineralogy but also its stronger geometry this process constitutes both reaction and microstructural softening the deformation mechanism here was thus one of dissolution precipitation creep activated at considerably lower stresses than might be predicted in quartzo feldspathic rocks at the same lower greenschist facies conditions this article is protected by copyright all rights reserved

palynofacies analysis and organic walled dinoflagellate cysts as indicators of palaeo hydrographic changes an example from holocene sediments in skalafjord faroe islands abstract this study documents holocene variations in organic matter deposition from ca 6350 cal yr bc to ad 1430 in skalafjord faroe islands and uses this information to assess palaeo hydrographic conditions the chronology of the interval studied is based on five ams 14 c ages based on the total sedimentary organic content the sediments dating to ca 6350 cal yr bc to ad 160 have been deposited under dysoxic bottom water conditions suggesting good ventilation in the water column the sediments dating to ca ad 160 1090 have been deposited under decreasing oxygen availability from ad 1090 to 1430 suboxic bottom water conditions characterised the fjord high terrestrial influx characterised most sediments in the study interval however moderate terrestrial influx was recorded in sediments dating to ca 6350 5670 cal yr bc based on the dinoflagellate cyst assemblages changes in the nutrient availability were inferred in the waters of the fjord over the study period the nutrients were minimal at ca 6350 5670 cal yr bc they increased in the interval ca 5670 685 cal yr bc and became very abundant at ca 685 cal yr bc to ad 1260 a decreasing trend in nutrient availability was inferred in sediments of age ca ad 1260 1430 a qualitative approach was used for the reconstruction of holocene sea surface temperature conditions based on dinoflagellate cyst and acritarch assemblages the estimated sea surface parameters highlighted the mid holocene final stage of the climatic optimum ca 6350 5300 cal yr bc the neo glaciation period ca 5300 cal yr bc to ad 260 a general climatic amelioration during the period ca ad 260 1090 and a cooling at ca ad 1090 1260

the metamorphic environment of the sgurr beag slide a major crustal displacement zone in proterozoic moine rocks of scotland new evidence from the sw northern highlands of scotland establishes the southerly extension of the sgurr beag slide interpretation of changes in the mineralogy of calcsilicate rocks particularly the use of the anorthite content of plagioclase feldspar as an index of metamorphic grade together with consideration of the texture and mineralogy of pelitic rocks suggests that the slide juxtaposes crustal segments of different metamorphic grade and history movement on the slide post dates a major phase of regional metamorphism and two phases of regional deformation of precambrian age was synchronous with a regional fold forming event and regional metamorphism at or before c 467 ma caledonian and was followed by regional folding models of the thermal effects of displacement across syn metamorphic shear zones are investigated with particular reference to the roles of thermal relaxation and levels of shear strain a model based on the development of a ductile syn metamorphic asymmetric shear zone best explains the metamorphic patterns associated with the sgurr beag slide an original low to moderate easterly dip is implied with north westerly upthrusting of the eastern crustal block

calcareous nannofossil and dinoflagellate stratigraphy across the cretaceous tertiary boundary at hor hahar israel in israel the cretaceous tertiary k t boundary at hor hahar occurs within the interval from the top of the ghareb formation maastrichtian to just below the horizon of dark marl and clay within the overlying taqiye formation paleocene the studied interval contains all the calcareous nannofossil zones micula prinsii latest maastrichtian markalius inversus np1 earliest paleocene andcruciplacolithus tenuis np2 early paleocene they correlate in sequence with theabathomphalus mayaroensis p0 p1a p1b and p1c planktic foraminiferal zones the palynological assemblages consist mainly of dinocysts with only few pollen grains and spores these assemblages are used to interpret five stratigraphic phases of environmental change across the k t boundary in the hor hahar section in the latest maastrichtian there is an overwhelming dominance of the nannofossilmicula decussata which probably reflects environmental stress preceding the terminal cretaceous mass extinction a nearshore marine environment at the boundary is suggested by the increase in number of specimens of the dinocystcyclonephelium and by the predominance of terrigenous organic matter sediment there followed two episodes of transgression and regression the calcareous cyst producing dinoflagellatethoracosphaera futterer 1976 becomes dominant in two episodes at the boundary and approximately one meter above it it alternates in abundance with the organic walled dinoflagellates which suggests that different environmental parameters were operating for each group maastrichtian dinocysts decline in abundance toward the k t boundary they reach greatest abundance and species diversity at the same strata where foraminiferids recover after their mass extinction at the boundary calcareous nannofossils recover only later in the early paleocene changes in 13c and total organic carbon as as well as dinocyst and nannofossil composition indicate an episode of strong ecological stress about one meter above the boundary

limited global change due to the largest known quaternary eruption toba 74 kyr bp abstract the 74 kyr bp super eruption of toba volcano in sumatra is the largest known quaternary eruption on the basis of preserved deposits the eruption magnitude has been estimated at 7 10 15 kg 2800 km 3 of dense magma the largest sulphate anomaly in the greenland ice sheet project 2 core has been identified as fallout from toba s stratospheric aerosol veil correlation of the sulphate and oxygen isotope stratigraphy of the ice core suggests that the toba eruption might have played a role in triggering a millennium of cool climate prior to dansgaard oeschger event 19 although a comparable stadial preceded event 20 a possible 6 yr duration volcanic winter immediately following the eruption has also been proposed as the cause of a putative bottleneck in human population supporting in a general way the garden of eden model for the origin of modern humans however along with counter arguments regarding the timing of any demographic crash there remain major gaps in our understanding of the 74 kyr bp toba eruption that hinder attempts to model its global atmospheric and climatic and hence human consequences the tephra record reveals basic aspects of the eruption style but calculations of the duration and hence intensity and plume height of the event are poorly constrained furthermore estimates of the sulphur yield of the erupting magma central to predictions of its atmospheric and climatic impacts vary by two orders of magnitude 3 5 330 10 10 kg previous estimates of globally averaged surface cooling of 3 5 c after the eruption are probably too high a figure closer to 1 c appears more realistic the volcanological uncertainties need to be appreciated before accepting arguments for catastrophic consequences of the toba super eruption

ten years of satellite observations reveal highly variable sulphur dioxide emissions at anatahan volcano mariana islands satellite remote sensing enables continuous multiyear observations of volcanic activity in remote settings anatahan mariana islands is a remote volcano in the western north pacific available ground based measurements of sulphur dioxide so2 gas emissions at anatahan place it among thelargest volcanic so2 sources worldwide these ground based measurements however are restricted to eruptive intervals anatahan s activity since 2003 has been dominated temporally by prolonged periods of quiescence using 10 years of satellite observations from omi airs sciamachy and gome 2 we report highly variable so2 emissions within and between eruptive and quiescent intervals at anatahan we find close correspondence between levels of activity reported at the volcano and levels of so2 emissions detected from space eruptive so2 emission rates have a mean value of 6400 t d 1 but frequently are in excess of 20 000 t d 1 conversely so2 emissions during quiescent intervals are below the detection limit of space based sensors and therefore are not likely to exceed 300 t d 1 we show that while anatahan occupies a quiescent state for 85 of the past 10 years only 15 of total so2 emissions over this interval occur during quiescence with the remaining 85 released in short duration but intense syn eruptive degassing we propose that the integration of multiyear satellite data sets and activity histories are a powerful complement to targeted ground based campaign measurements in better describing the long term degassing behavior of remote volcanoes

volcanic plume monitoring at mount etna by diffusive passive sampling 1 this paper reports the use of diffusive tubes in determining hf hcl and so2 in the volcanic plume of mount etna in an attempt to highlight the potential of this method in studying volcanoes in a first application a network of 18 diffusive tubes was installed on etna s flanks aimed at evaluating the atmospheric dispersion of the volcanic plume on a local scale results showed a monotonic decrease in volatile air concentrations with distance from the craters hf from 0 15 to 0 003 mol m 3 hcl from 2 to 0 01 mol m 3 and so2 from 11 to 0 04 mol m 3 revealing the prevalently volcanic contribution matching of so2 hcl and hcl hf volatile ratios with contemporaneous measurements at the summit craters validated the use of diffusive tubes in tracing the chemical features of a volcanic plume from remote locations a first tentative assessment of dry deposition rates of volcanogenic acidic gases was also made yielding 2 5 74 t d 1 so2 0 6 17 t d 1 hcl and 0 02 0 6 t d 1 hf and revealing the potential environmental impact of gas emissions in a second experiment carried out during the recent october 2002 to february 2003 eruption of etna diffusive tubes provided a continuous record of the chemical composition of the eruptive plume from a safe distance of 1 km from the vents thus considerably decreasing the risks involved in sampling this highlighted a clear time decrease in so2 concentrations and so2 hcl ratios which was interpreted as due to progressive exhaustion of volatile degassing and eruption energy

geochemical and palynological sea level proxies in hemipelagic sediments a critical assessment from the upper cretaceous of the czech republic geochemical and palynological records are presented for an expanded turonian coniacian hemipelagic succession in the central bohemian cretaceous basin a high resolution stratigraphic framework is provided by biostratigraphy and organic carbon stable isotope 13corg chemostratigraphy a short term 100 kyr sea level curve has been derived from high resolution transgressive regressive maxima shore proximity data established from basin wide sediment geometries the viability of geochemical and palynological parameters as potential sea level proxies is tested against this independently derived sea level record elemental chemostratigraphy is demonstrated to offer a reliable means of identifying medium to long term 0 4 2 4 myr sea level trends manganese maxima are associated with periods of high sea level and troughs with intervals of low sea level falling mn contents accompany regression and rising values transgression major transgressive events associated with medium term sea level change are marked by sharp increases in ti al ratios but short term 100 kyr sea level cycles are not consistently identified long term 13corg variation and dinoflagellate cyst species richness are positively correlated and show similarities to the sea level curve baseline trends have a cycle duration close to the 2 4 myr long eccentricity cycle dinocyst species richness closely follows short term changes in sea level with marked increases in dinocyst diversity coincident with most short term flooding events periods of rapid sea level rise caused an influx of a more diverse outer shelf assemblage into the study area together with the addition of shallower water species some of which may have been transported into the central basin by hypopycnal flows changes in the proportion and abundance of peridinioid dinoflagellate cysts principally palaeohystrichophora infusorioides were controlled principally by changing nutrient levels proximity proxies derived from geochemical and palynological data are not always consistent with the independent sea level model this exemplifies the need to understand all factors influencing elemental geochemical and palynological proxies before making simplistic sea level interpretations

first synoptic analysis of volcanic degassing in papua new guinea we report the first satellite based survey of volcanic sulphur dioxide so2 degassing in papua new guinea using ozone monitoring instrument omi data omi is sensitive to low level passive degassing these observations are useful for volcano monitoring hazard assessment particularly aviation hazard and assessment of arc geochemical budgets and are of immense value in remote regions with little ground based instrumentation such as papua new guinea we identify bagana manam rabaul ulawun and langila as the active sources of volcanic so2 in papua new guinea with bagana being the largest source we present an omi so2 time series for 2005 2008 and a total detected regional output of 1 8 109 kg so2 about 40 of emissions were released by major eruption events at manam january 2005 bagana june 2006 and rabaul october 2006 over the past century however we estimate that major explosive eruptions contribute 5 of the arc scale so2 emission budget ground based doas measurements of so2 degassing at five of papua new guinea s volcanoes are compared with our omi observations the total omi so2 output is only 20 of the total extrapolated from doas a discrepancy which we demonstrate is consistent with other volcanic arcs therefore the true total regional so2 output may be considerably higher than that detected by omi uncertainties in the omi so2 data include the effects of in plume chemical processing and dilution of so2 prior to the satellite overpass omi s reduced sensitivity to low levels of so2 in the planetary boundary layer and interference by meteorological clouds