volatile induced magma differentiation in the plumbing system of mt etna volcano italy evidence from glass in tephra of the 2001 eruption mount etna volcano was shaken during the summer 2001 by one of the most singular eruptive episodes of the last centuries for about 3 weeks several eruptive fractures developed emitting lava flows and tephra that significantly modified the landscape of the southern flank of the volcano this event stimulated the attention of the scientific community especially for the simultaneous emission of petrologically distinct magmas recognized as coming from different segments of the plumbing system a stratigraphically controlled sampling of tephra layers was performed at the most active vents of the eruption in particular at the 2 100 m cal and at the 2 550 m lag scoria cones detailed scanning electron microscope and energy dispersive x ray spectrometer sem eds analyses performed on glasses found in tephra and comparison with lava whole rock compositions indicate an anomalous increase in ti fe p and particularly of k and cl in the upper layers of the lag sequence mass balance and thermodynamic calculations have shown that this enrichment cannot be accounted for by classical differentiation processes such as crystal fractionation and magma mixing the analysis of petrological features of the magmas involved in the event integrated with the volcanological evolution has evidenced the role played by volatiles in controlling the magmatic evolution within the crustal portion of the plumbing system volatiles constituted of h2o co2 and cl complexes originated from a deeply seated magma body dbm their upward migration occurred through a fracture network possibly developed by the seismic swarms during the period preceding the event in the upper portion of the plumbing system a shallower residing magma body abt had chemical and physical conditions to receive migrating volatiles which hence dissolved the mobilized elements producing the observed selective enrichment this volatile induced differentiation involved exclusively the lowest erupted portion of the abt magma due to the low velocity of volatiles diffusion within a crystallizing magma body and or to the short time between volatiles migration and the onset of the eruption furthermore the increased amount of volatiles in this level of the chamber strongly affected the eruptive behavior in fact the emission of these products at the lag vent towards the end of the eruption modified the eruptive style from classical strombolian to strongly explosive

application of near real time radial semblance to locate the shallow magmatic conduit at kilauea volcano hawaii 1 radial semblance is applied to broadband seismic network data to provide source locations of very long period vlp seismic energy in near real time with an efficient algorithm and adequate network coverage accurate source locations of vlp energy are derived to quickly locate the shallow magmatic conduit system at kilauea volcano hawaii during a restart in magma flow following a brief pause in the current eruption the shallow magmatic conduit is pressurized resulting in elastic radiation from various parts of the conduit system a steeply dipping distribution of vlp hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the halemaumau pit crater the distinct hypocenters suggest the shallow plumbing system beneath halemaumau consists of a complex plexus of sills and dikes an unconstrained location for a section of the conduit is also observed beneath the region between kilauea caldera and kilauea iki crater

eocene monsoon prevalence over china a paleobotanical perspective abstract proxy based quantitative estimates of eocene climates can be made from marine isotope records for ocean conditions or fossil plants for terrestrial environment however our understanding about eocene terrestrial climates is derived mainly from north america and europe and little is known about east asia previous qualitative paleoclimate studies briefly revealed three climatic regimes across china during the eocene with a planetary wind dominated subtropical to tropical arid zone in the central part i e the subtropical highs which was flanked by the subtropical climate zone in the north and tropical climate zone in the south but such a pattern of paleoclimatic zonation still requires a test from quantitative study based on analyses of 66 plant assemblages carefully selected from 37 fossil sites throughout china we here report the first large scale quantitative climatic results and discuss the eocene climatic patterns in china our results demonstrate that the eocene monsoonal climate must have been more or less developed over china judging from the presence of apparent seasonality of both temperature and precipitation revealed by our quantitative estimation this appears not to support the previously claimed eocene planetary wind dominated climate system at least in the region of eastern china in addition the research indicates that with a slight declining trend of mat during the eocene the winter temperature substantially dropped in tropical southern china during the middle to late eocene interval this might be related to the development of a weak eocene kuroshio current in the southwestern pacific and or a significantly enhanced paleo winter monsoon from siberia

the evolution of miocene climates in north china preliminary results of quantitative reconstructions from plant fossil records the miocene climate evolution in north china is preliminarily discussed by means of comparisons in seven climate parameters quantitatively reconstructed by the coexistence approach on 34 selected macro and microfloras over north china the miocene temperatures show no great difference in the western and eastern part of north china temperature fluctuations particularly in mean annual temperature are found within floras from several sites the fluctuation pattern from a climate optimum in the mid miocene to cooling decline in the late miocene is generally consistent with the global trend of miocene temperature change the reconstructed precipitation from all the sites studied shows much wetter conditions in north china during the miocene than at present which corroborates the results from paleoprecipitation proxy of fossil mammals like the situation in paleo temperature the miocene precipitation from north china shows no distinct difference between the western and eastern regions it is suggested that north china particularly in the western part was by no means under an arid or semi arid environment during the miocene north china is an ideal region for study of the impact of the east asian monsoon system however the pattern of precipitation change derived from the monsoon index msh and mean annual precipitation map shows contradictory results therefore there appears no definite conclusion on when the east asian summer monsoon intensified possible reasons for inconsistency in temperature and precipitation changes are discussed directions of future work to improve the resolution of climate evolution are also pointed out c 2010 elsevier b v all rights reserved

precipitation patterns in the miocene of central europe and the development of continentality abstract understanding climate patterns with their decisive influence on plant distribution and development is crucial to understanding the history of vegetation patterns in europe during the miocene this paper presents the detailed analyses of several precipitation parameters including monthly precipitation of the wettest driest and warmest months for five miocene stages in conjunction with seasonality of temperature those parameters provide a meaningful measure of continentality and can help to document miocene climate changes and patterns and their possible influence on vegetation climate reconstructions provided here are entirely based on palaeobotanical material in total 169 miocene floras were selected including 14 burdigalian 41 langhian 40 serravallian 36 tortonian and 38 messinian localities all floras were analysed using the coexistence approach the analysis of several precipitation parameters the statistical inter correlation of results and the comparison with modern patterns provides a comprehensive account on miocene precipitation miocene climatic changes after the mid miocene climatic optimum mmco are evidenced in our data set by three major factors i e 1 increasing seasonality of temperature 2 changes in the annual distribution of precipitation towards a precipitation peak in summer and 3 a late increase of longitudinal gradients of precipitation parameters evidence of continental climate in eastern europe first appears during the messinian in addition to changes in temperature shifts in the annual distribution of precipitation may have played a major role in post langhian climate changes however the most significant climatic transformations occurred later from the end of miocene through to the present several authors have described patterns of vegetation development in europe that are in good agreement with our finding of the first evidence for continental climate in eastern europe during the messinian our data do not support an onset of opening of vegetation during the tortonian or even earlier as has been described for some parts of eastern and southern europe possibly either non climatic parameters influenced such an early development or our data lack the required resolution and or spatial coverage to fully decipher the influence of continentality on vegetation and to correlate climate and vegetation statistically nevertheless climatic data that quantify continentality can provide a sound basis for explaining the expansion of grassland in eurasia

mount etna geochemical signals of magma ascent and unusually extensive plumbing system fiveyearsofgasmonitoringfromselectedsitessuggestthatmtetna splumbingsystemismuchmoreextensivethanpreviously reported it extends at least 40 km sw from thevolcano s boundary along the ne sw regional fault whereit discharges about 200 tons day of gas containing heliumwith mantle type isotopic composition synchronousvariations of

reconstruction of neogene zonal vegetation in south china using the integrated plant record ipr analysis abstract reconstructions of past vegetation are crucial for our understanding of palaeoenvironments however we still lack good quantitative reconstructions for the neogene vegetation of china this geological time is key for the development of the modern vegetations in china because it corresponds to the establishment and evolution of the south east asian monsoon system the present study uses integrated plant record ipr vegetation analysis for the first time on the chinese neogene data including 71 palaeobotanical sites from five time intervals early early miocene aquitanian early burdigalian late early to early middle miocene late burdigalian early langhian late middle miocene late langhian serravalian late miocene to earliest pliocene tortonian messinian early zanclean and pliocene late zanclean piacenzian based on the ecophenological type of the nearest living relative to the fossils ipr analysis reconstructs six types of vegetation broad leaved deciduous forests mixed mesophytic forests broad leaved evergreen forests subhumid sclerophyllous forests xeric open woodlands and xeric grasslands or steppe the geographic distribution of reconstructed palaeovegetation shows a distinct latitudinal gradient which is congruent with the latitudinal temperature gradient recognised from previous studies throughout the neogene the broad leaved deciduous bld component is greater in the more northern regions whereas the broad leaved evergreen ble component is greater in the more southern areas during the pliocene there was a further rise of the ble component in the southern areas indicating an increasingly warm and moist climate an episodic longitudinal aridity gradient was also recorded during the neogene the more western areas were drier than the eastern ones in the early miocene but this gradient vanished in the late miocene with all areas having a balanced supply of moisture a second episode of aridification of the western regions occurred in the pliocene

late cenozoic genus fupingopollenites development and its implications for the asian summer monsoon evolution an extinct palynomorph fupingopollenites was used as the basis for a discussion of the late cenozoic asian summer monsoon asm evolution and its possible driving forces based on the spatial and temporal variations in its percentages across inner and east asia we found that fupingopollenites mainly occurred in east asia with boundaries to the ne of ca 42 degrees n 135 degrees e and nw of ca 36 degrees n 103 degrees e during the early miocene ca 23 17 ma this region enlarged westwards reaching the eastern qaidam basin ca 36 degrees n 97 5 degrees e during the middle miocene ca 17 11 ma before noticeably retreating to a region bounded to the nw at ca 33 degrees n 105 degrees e during ca 11 5 3 ma the region then shrank further in the pliocene with the ne boundary shrinking southwards to about 35 degrees n 120 degrees e the area then almost disappeared during the pleistocene 2 6 0 ma the flourishing and subsequent extinction of fupingopollenites is indicative of a narrow ecological amplitude with a critical dependence on habitat humidity and temperature most likely mean annual precipitation map 1000 mm and mean annual temperature mat 10 degrees c therefore the fupingopollenites geographic distribution can indicate the humid asm evolution during the late cenozoic revealing that the strongest asm period occurred during the middle miocene climate optimum mmco similar to 17 14 ma after which the asm weakened coincident with global cooling we argue that the global cooling played a critical role in the asm evolution while the tibetan plateau uplifts made a relatively small contribution c 2015 international association for gondwana research published by elsevier b v all rights reserved

the neogene of eurasia spatial gradients and temporal trends the second synthesis of neclime article i nfo this volume represents the second synthesis of the international open research network neclime neogene climate evolution in eurasia that was established in 2000 to study climate change in eurasia during the neogene and its impact on ecosystems the main objectives of neclime research are 1 proxy data based quantitative reconstructions of neogene climate in eurasia by means of standardised techniques 2 the modelling of atmospheric and oceanic circulation and of biomes using neogene boundary conditions and 3 the analysis of the interaction between palaeogeography vegetation and climate presently 94 scientists from 34 countries are neclime members contributing with their published data to a collective data base integrating proxies from various sources such as palaeobotany vertebrate palaeontology and geology the following core topics are addressed in the volume precipitation patterns and landscape opening the asian monsoon systems the potential of past climates for the evaluation of future climate change scenarios as well as short term change and variability of climate highlights of the single contributions are summarised in a proxy data section and in a modelling section respectively it is shown that the integrative approach presented in this volume brings about a much better and much more detailed understanding of neogene climate dynamics in eurasia than previously achieved even though neogene climate changes may have regional aspects differing considerably from each other and from the general global trend the results from the various proxy and modelling studies consistently show that later neogene cooling implicated more pronounced latitudinal and longitudinal gradients on the other hand the issue reveals a number of problems and questions resulting from the contrary nature of palaeozoological and palaeobotanical palaeoclimate proxies and modelling results mainly at a more regional level the models can not yet explain the relatively warm high latitudes during the neogene and we still do not sufficiently understand the role of the various boundary conditions such as co2 palaeogeography and palaeovegetation in the observed neogene climate change and its regional differentiation these apparent uncertainties underline the importance of the study of palaeo scenarios in order to enhance the reliability of future climate projections

chronological sequence and subdivision of chinese neogene mammalian faunas six land mammal ages are recognized for the neogene of east asia the ages are based upon updated large and small mammal faunas and replace or redefine the land mammal stages erected by li et al 1984 comparisons and correlations are made to faunas in europe northern and southern asia and north america in addition methods of utilizing mammalian faunal data to define and recognize geochronologic ages are discussed

unravelling the processes controlling gas emissions from the central and northeast craters of mt etna abstract we measured volcanic gas emissions from the northeast crater nec and central crater cc of mount etna on 21st july 2008 and 3rd and 31st august 2009 using a novel lightweight open path fourier transform infrared spectrometry op ftir in active mode with a portable infrared lamp contemporaneously we measured the so2 flux of the total gas emission released by the combined summit craters 14 km downwind and the so2 flux emitted by the nec measured at the summit combining these data we determined the flux of the major volcanic components h2o co2 so2 hcl and hf emitted individually from cc and nec craters the results reveal similar so2 hcl ratios but distinct co2 so2 ratios 1 3 and 10 9 for nec and cc respectively and an order of magnitude greater co2 flux from the cc compared with the nec a simple model in which the nec branches from a central feeding conduit at a depth of 2 km can reproduce these observations we highlight that in such a system short term variations in co2 so2 ratios at each crater can occur due to minor variations in the magma gas flux entering each conduit at the branch without an overall change in magma supply co2 so2 variations measured at individual craters may therefore be unrepresentative of the volcanic system and require cautious interpretation monitoring of the total co2 and so2 fluxes emitted from each crater is on the contrary an optimal monitoring strategy and can be achieved using a combination of co2 so2 instruments and so2 imaging cameras

reappraisal of miocene eolian deposition in tianshui basin china based on an investigation of stratigraphy and provenance eolian deposition in china is intimately related to asian desertification the fine grained sediments in the cenozoic basins along the northeastern tibetan plateau are increasingly reported as eolian deposits due to their loess like characteristics thus extending the onset time of asian desertification from the late miocene to the early miocene however the basin scale stratigraphic correlation and geographic origin of these fine grained sediments remain poorly investigated limiting any interpretation of the transportation and paleoclimatic conditions responsible for their emplacement this study combines analyses of detrital zircon u pb geochronology and heavy mineral assemblages to present the first comprehensive stratigraphic and provenance study of miocene sediments in the tianshui basin in northeastern tibet comparison of results from 64 sand sized and silt sized samples from various sedimentary beds across the basin reveals that the main stratigraphic packages can be correlated basin wide confirming that the silt sized sediments were a natural part of the basin fill statistical visualizations of the large data set from northern and western china clearly shows that the west qinling mountains are the main source of the tianshui basin silts contribution estimates corroborate this conclusion and eliminate the likelihood of substantial contributions from other mountains and drylands moreover the significant differences between the tianshui basin silts and the chinese loess plateau red clay are reflected by their heavy mineral compositions and euhedral zircon u pb ages these provenance analyses strongly contradict the previous assumption of desert origin for the tianshui basin silts moreover the northward transport of the tianshui basin silts conflicts with the prevailing dust pathway driven by the asian westerlies and winter monsoons which do not support the eolian interpretation for their formation consequently we suggest that the miocene tianshui basin silts cannot be used as an indicator of extensive desertification in contrast with the suggestions of previous studies this proposal undermines the corresponding hypothesis of an early miocene onset of asian interior desertification and further raises questions about the validity of prevalent paleoclimatic interpretations drawn from fine grained basin sediments

evidence of deep magma degassing and ascent by geochemistry of peripheral gas emissions at mount etna italy assessment of the magmatic reservoir pressure 1 five gas discharges in the area of mount etna volcano italy and in the near hyblean plateau have been monitored since 1996 all the emissions displayed low contributions from crustal fluids whereas magmatic gases were the main component selective dissolution of these gases into hydrothermal aquifers has been recognized and modeled allowing us to calculate the original composition of the magma released gases the inferred composition of the magmatic gases exhibits synchronous variations of he ne and he co2 ratios which are coherent with the magma degassing process on the basis of numerical simulations of volatile degassing from etnean basalts we have computed the initial and final pressures of the magma batches feeding the emissions we thus can define the levels of the etna plumbing system where magmas are stored pressure values were around 360 and 160 mpa for initial and final stages respectively meaning related depths of about 10 and 3 km below sea level matching those obtained by geophysical investigations for the deep and shallow magma reservoirs in addition we have been able to recognize episodes of magma migration from the deeper reservoir toward the shallow one an important magma injection into the shallow storage volume was detected during the onset of the 2001 eruption 17 july no further injection had taken place during this period until september 2001 providing a possible reason for the quick exhaustion of the eruption in view of this we suggest that the sampled emissions are a powerful geochemical tool to investigate the etna s plumbing system and its magma dynamics as well as the development of eruptive events

asynchronous responses of east asian and indian summer monsoons to mountain uplift shown by regional climate modelling experiments it has been demonstrated in climate models that both the indian and east asian summer monsoons ism and easm are strengthened by the uplift of the entire asian orography or tibetan plateau tp i e bulk mountain uplift such an effect is widely perceived as the major mechanism contributing to the evolution of asian summer monsoons in the neogene however geological evidence suggests more diachronous growth of the asian orography i e regional mountain uplift than bulk mountain uplift this demands a re evaluation of the relation between mountain uplift and the asian monsoon in the geological periods in this study sensitivity experiments considering the diachronous growth of different parts of the asian orography are performed using the regional climate model cosmo clm to investigate their effects on the asian summer monsoons the results show that different from the bulk mountain uplift the regional mountain uplift can lead to an asynchronous development of the ism and easm while the ism is primarily intensified by the thermal insulation mechanical blocking effect of the southern tp zagros mountains the easm is mainly enhanced by the surface sensible heating of the central northern and eastern tp such elevated surface heating can induce a low level cyclonic anomaly around the tp that reduces the ism by suppressing the lower tropospheric monsoon vorticity but promotes the easm by strengthening the warm advection from the south of the tp that sustains the monsoon convection our findings provide new insights to the evolution of the asian summer monsoons and their interaction with the tectonic changes in the neogene

subduction like fluids in the genesis of mt etna magmas evidence from boron isotopes and fluid mobile elements abstract new whole rock b sr nd isotope ratios and 87sr 86sr on clinopyroxenes have been collected to study the enrichment of fluid mobile elements fmes observed in mt etna volcanics etna volcano one of the most active in the world is located in an extremely complex tectonic context at the boundary between colliding african and european plates the analytical work focuses on current 1974 1998 and historic 1851 1971 eruptive activity including some key prehistoric lavas in order to interpret the secular shift of its geochemical signature to more alkaline compositions boron is used as a tool to unravel the role of fluids in the genesis of magmas revealing far reaching consequences beyond the case study of mt etna small variations are observed in 11b 3 5 to 8 0 87sr 86sr 0 70323 0 70370 and 143nd 144nd 0 51293 0 51287 moreover temporal evolution to higher 11b and 87sr 86sr and to lower 143nd 144nd is observed in the current activity defining a regular trend sr isotopic equilibrium between whole rock and clinopyroxene pairs indicates the successive introduction of three distinct magma types into the etna plumbing system over time these are characterized by differing degrees of fme enrichment in addition certain lavas exhibit evidence for country rock assimilation magma fluid interaction or magma mixing in the shallow feeding system at times these processes apparently lowered magmatic 11b and or induced sr isotopic disequilibrium between whole rock and clinopyroxene the regular increase of 11b values is correlated with nb fme and 87sr 86sr ratios these correlations are consistent with simple mixing between the mantle source and aqueous fluids derived from nearby ionian slab the best fit of mt etna data is obtained using an enriched morb mantle source and a fluid phase with 11b of about 2 and 87sr 86sr of 0 708 we argue that the slab window generated by differential roll back of subducting ionian lithosphere with respect to sicily allows the upwelling of asthenosphere from below the subduction system and provides a suitable path of rise for subduction related fluids the increasing geochemical signature of fluid mobile elements enrichment to mt etna lavas is considered a consequence of the progressive opening of slab window through time

validation of temperature precipitation based aridity index paleoclimatic implications abstract water availability in the ecosystem is one of the most crucial environmental factors that determines global terrestrial biome distribution however aridity humidity conditions in the geologic past are difficult to quantify mainly owing to the lack of a proper parameter by using modern global climatic data we here examine five selected previously proposed aridity indices ais in which the climatic variables involved including both precipitation and temperature are simple and likely available in studies of paleoclimatology and paleoecology although with different degrees of uncertainty they were first evaluated along the modern climatic zones of eastern china with the main metric of thornthwaite humidity index hi and with the supplementary reference of soil moisture index smi and near ground atmospheric relative humidity rh then ais and the mean annual precipitation map were further statistically compared with hi smi and rh respectively based on 1189 monitored data sets from meteorological stations over the world the results show that the koppen aridity index aikoppen expressed as mean annual precipitation divided by mean annual temperature plus a constant of 33 is the most accurate and precise index among all selected indices supported by the highest correlation coefficient respectively to hi smi and rh three widely employed major indicators sensitive to hydrological dynamics in climatology and meteorology specifically aikoppen does well mirror corresponding hi along four representative transects from north america south america africa and australia which cover the typical arid and humid climates and span the main terrestrial biome types moreover our results also distinctly reveal that as also shown by many studies on modern climate precipitation alone is inadequate to measure the hydrological condition because both temperature and evapotranspiration are two other critical factors that strongly influence water balance in the ecosystem meanwhile evapotranspiration is mainly affected by temperature based on the validated aikoppen we briefly discuss the aridity humidity condition in china during the middle miocene the results demonstrate that moisture did decrease westward but it is also clear that western china in the middle miocene appears not to have been as dry as previously thought indicated by the aikoppen values representing a sub humid to humid climate

late miocene and pliocene large land mammals and climatic changes in eurasia the fossil teeth of land mammals offer a powerful tool to map the regional details of past climate change in the terrestrial realm we use meanplant eaterhypsodonty molarcrownheight oflateneogenemammallocalitiestomaplatemioceneandpliocenepalaeoprecipitation on the eurasian continent and with higher temporal resolution in europe the results show that the mid latitude drying in eurasia affected thecentral parts ofthecontinentfirst and thatthedrying of western europeafter about7 8maseemstohavecoincidedroughlyintimewith a return to more humid conditions in eastern asia with a return to a drier east and more humid west in the pliocene within europe the hypsodonty based palaeoprecipitation maps suggest that the sequence from mn 9 to mn 12 ca 11 1 6 8 ma was dominated by an east west continental marine humidity gradient which gradually intensified and with a shift of dryer conditions eastwards in mn 12 ca 7 5ma thiswaspartlyoverlainfrommn13onwardsbyanorth southorientedgradient whichpersistedatleasttotheendofthepliocene the maps for both the earliest late miocene mn 9 ca 11 1 9 7 ma and the earliest pliocene mn 14 ca 4 9 4 2 ma show very low regional differentiation possibly suggesting perturbed phases in the evolution of the mammal communities analysis of hypsodonty and dietary structure of the mammalian plant eater community in europe during the entire interval shows that the miocene pliocene boundary was marked by a strong decrease in mesodont species and mixed feeders and an increase in brachydont species and omnivores in this view the shift in the latest miocene from east west to partly north south polarised hypsodonty patterns corresponds mainly to an increase in hypsodont species and grazers it seems probable that the east west gradient was primarily driven by precipitation while the north south gradient would also have been strongly influenced by temperature related effects of humidity

the interplay between climate and tectonics during the upward and outward growth of the qilian shan orogenic wedge northern tibetan plateau abstract mountains grow upward and outward when the accretion of material outpaces its removal mountain building is synergistically influenced by geodynamics internal structures crustal and lithospheric and climate the northward growth of the qilian shan which occupies a transition zone between the 4500 m high central tibetan plateau and the adjacent

developing a radiometrically dated chronologic sequence for neogene biotic change in australia from the riversleigh world heritage area of queensland abstract radiometric u pb ages are presented for the riversleigh world heritage fossil mammal site in northwestern queensland australia the ages are determined on speleothems which are generally found in intimate or well documented association with fossil remains and thus can be assumed to record the age of the latter with a high degree of confidence the new ages encompass the early 18 2 16 5 ma and middle miocene 15 1 13 5 ma deposits at riversleigh in addition to the younger rackham s roost site which returns early pleistocene ages together these provide a robust chronological framework for the interpretation of neogene biotic change in australia that has until now relied almost entirely upon biocorrelative techniques in particular they permit closer investigation of links between other regions faunas and allow comparison with other records of climatic and environmental change this is the first documented example of a methodology that has widespread potential application across many continents and throughout much of earth history

investigation of the he solubility in h2oâco2 bearing silicate liquids at moderate pressure a new experimental method we have designed the first available experimental method capable to investigate the solubility of inert gases in h2o co2 bearing silicate melts in a large range of pressures the method overcomes the difficulties imposed by the physical state of volatiles at room conditions experiments were done by using an internally heated pressure vessel where sealed capsules containing the sample are introduced the peculiarity of the method consists in the capability of loading in accurately known proportions even lower than ppm volatiles in a gaseous state at room conditions gas is loaded as a weighed amount of a gas bearing glass which was previously prepared by using the same gas as a pressure medium of a superliquidus experimental run by analyzing the gas concentration in the prepared glass the glass itself can be used as a gas source we applied this method in order to investigate the helium solubility in silicate melts having dissolved volatile mixtures mostly composed of h2o and co2 in a range of pressure suitable to provide useful information regarding pre eruptive magma degassing our results indicate that helium solubility is strongly affected by the h2o content in silicate liquid displaying an increase by about a factor three as a consequence of the addition of 3 wt h2o to the melt taking into account the physical mechanism of he dissolution the sites of the silicate melt structure where noble gases can be accommodated drastically increase by adding modest aliquots of h2o the influence of dissolved co2 on helium solubility is not certain although few signs would suggest an opposite effect with respect to h2o at least in basalt melts on the basis of the obtained results we could reasonably expect that the helium behavior during the degassing of h2o co2 bearing magmas is sensibly different with respect to a h2o co2 free silicate liquid therefore the effect of the major volatiles on noble gas solubility in magmas should be taken into account in the investigation of several geological processes such as magma genesis ascent and degassing or mantle evolution

the 1989 1990 activity of etna magma mingling and ascent of h2oclsrich basaltic magma evidence from melt inclusions abstract the melt inclusions in olivine phenocrysts from basaltic tephra erupted by etna volcano during the 1989 1990 eruptive period were investigated for major elements cl and s by electron microprobe fluorine by pigme particule induced gamma ray emission and h 2 o by sims the results indicate the ascent of basaltic magmas with different k 2 o concentrations possibly related to different feeding dykes lk basaltic melt inclusions rich in cl s and h 2 o are trapped in olivine fo 84 from the 1990 tephra and represent the early crystallization stage their composition in major elements is quite similar to those of most of the historic and even pre etnean alkali basalts but significantly lower in k 2 o compared with the 1989 1990 lavas only scarce hk basaltic melt inclusions were observed in the outer rim fo 79 6 of reversely zoned olivine phenocrysts and correspond to late crystallization stage at low pressure high sulfur concentration s 0 3 wt is a general characteristic of the etnean basaltic magmas with h 2 o s ratio as high as 7 the volatile abundances of the etna primitive basalts were computed at 1 45 wt for h 2 o 0 17 wt for cl and 0 047 wt for f with a high cl f ratio close to 3 6 the 1989 lava samples with cl at 660 90 ppm and f at 770 30 ppm have suffered a significant cl loss the possible behaviour of the volatile phase as co 2 h 2 o even cl is discussed with h 2 o and chlorine late degassing and an active role of h 2 o during the lava fountaining activity

composite minor intrusions as windows into subvolcanic magma reservoir processes mineralogical and geochemical evidence for complex magmatic plumbing systems in the british tertiary igneous province the rudh a chromain sill is a composite minor intrusion emplaced into jurassic sandstones on the south coast of the ross of mull nw scotland and is part of a suite of basic silicic sheets associated with the early development of the 58 56 ma mull central igneous complex new whole rock major and trace element data combined with sr nd pb isotope data indicate that two distinct magma end members were involved in the formation of the sill a tholeiitic basaltic andesite magma generated by contamination and fractional crystallization of regionally available olivine tholeiite basaltic magma and a rhyolitic magma produced predominantly through crustal melting of basement metasediments intermediate compositions at the gradational boundaries between the basic margins and silicic interior of the sill formed by high temperature diffusive hybridization within a compositionally zoned magma reservoir prior to sheet emplacement the basic portions of the sheet are replete with a large variety of crustal xenoliths as well as numerous gabbroic and noritic cumulate fragments the rudh a chromain sill therefore preserves evidence for the complex interplay between a number of magmatic processes which when combined with data from the remainder of the suite suggests that the magmatic plumbing system which fed the sill complex was not simply one large long lived magma chamber but rather a plexus of variably connected sheet like magma reservoirs

significant mid latitude aridity in the middle miocene of east asia abstract the east asian climate history during the neogene is a complicated and contentious issue in particular because of its bearing on the development of the east asian monsoon and tibetan uplift chronology here we present a paleoprecipitation analysis based on mean molar tooth height hypsodonty of large herbivorous mammals to investigate the spatial pattern of climate zonation in east asia during the middle miocene we show a generally humid and uniform situation before the late middle miocene replaced by a mid latitude arid belt from the late middle miocene into the earlier part of the late miocene these findings are concordant with the global phenomena of the middle miocene climate optimum and the subsequent cooling and suggest that the predominant climate in east asia for most of the miocene was planetary rather than monsoonal our results support a late initiation of the east asian summer monsoon coincidentally with the beginning of eolian red clay deposition in the later late miocene at 7 8 ma

faulting on the western flank of mt etna and magma intrusions in the shallow crust surface deformations on the western flank of mt etna volcano spanning 1980 2004 have been analysed as they pertain to stress interactions between magma intrusions within the shallow crust along the s se rift and faulting sensitivity during this period an accurate analysis of strain parameters computed by inversion of sw electro optical distance data suggested that the observed strong displacements on this flank of the edifice can also be related to dextral shear movements along a roughly ne sw buried fault crossing the area covered

elemental and isotope covariation of noble gases in mineral phases from etnean volcanics erupted during 2001 2005 and genetic relation with peripheral gas discharges abstract during 2001 2005 mount etna was characterized by intense eruptive activity involving the emission of petrologically different products from several vents which involved at least two types of magma with different degrees of evolution we investigated the ratios and abundances for noble gas isotopes in fluid inclusions trapped in olivines and pyroxenes in the erupted products we confirm that olivine has the most efficient crystalline structure for preserving the pristine composition of entrapped gases while pyroxene can suffer diffusive he loss both the minerals also experience noble gas air contamination after eruption helium isotopes of the products genetically linked to the two different magmas fall in the isotopic range typical of the etnean volcanism this result is compatible with the metasomatic process that the etnean mantle is undergoing by fluids from the ionian slab during the last ten kyr as previously inferred by isotope and trace element geochemistry significant differences were also observed among olivines of the same parental magma that erupted throughout 2001 2005 with 3he 4he ratios moving from about 7 0 ra in 2001 volcanites to 6 6 ra in 2004 2005 products changes in he abundances and isotope ratios were attributed to variations in protracted degassing of the same magma bodies from the 2001 to the 2004 2005 events with the latter lacking any contribution of undegassed magma the decrease in 3he 4he is similar to that found from measurements carried out every fifteen days during the same period in gases discharged at the periphery of the volcano to our knowledge this is the first time that such a comparison has been performed so in detail and provides strong evidence of the real time feeding of peripheral emissions by magmatic degassing

monsoon variability over peninsular india during late pleistocene signatures of vegetation shift recorded in terrestrial archive from the corridors of western ghats abstract the fossil flora recovered from the kangvai well ratnagiri district maharashtra 17 53 41 n 73 12 23 e has been used to reconstruct the monsoon variations and seasonal rainfall pattern during the late pleistocene 44 020 390 years bp by using the coexistence approach the reconstruction suggests that the southwest sw and northeast monsoons ne contributed 64 and 18 of the total rainfall respectively moreover the pre monsoon showers were responsible for about 15 of the annual rainfall as both sw and ne monsoons were very active along with the pre monsoonal rainfall the length of rainy season increased and extended up to 9 months in a year favouring the evergreen continuum and prevalence of wet evergreen forests until the late glacial maximum or slightly prior to it however due to the weakening of ne and pre monsoon rainfall later in the late pleistocene and early holocene the area experiences only four months of rainy season now on account of the present day sw monsoon these changes resulted in the extinction of wet evergreen taxa which are now endemic to the wetter parts of western ghats from the fossil locality our reconstruction agrees with the previous studies from the western ghats suggesting that the wet evergreen taxa require

east asian summer monsoon weakening after 7 5 ma evidence from combined planktonic foraminifera mg ca and δ18o odp site 1146 northern south china sea abstract the monsoon system represents one of the basic elements of global atmospheric circulation its evolution and variability over long periods of geologic time play a significant role in our understanding of global climate in this study we focus on the late miocene interval from 10 ma to 6 ma a period of postulated profound ecological and environmental shifts in east and south asia the combined approach of measuring planktonic foraminiferal mg ca ratios and stable oxygen isotopes from ocean drilling program odp site 1146 enabled us to reconstruct temperature independent seawater 18o i e proxy for sea surface salinity variations in order to reconstruct the hydrography in the northern south china sea located offshore the pearl zhujiang river or its predecessor the location of odp site 1146 is considered to provide a most sensitive record for detecting potential changes in freshwater input river run off as a result of changes in continental humidity and hence changes in east asian summer monsoon easm climate local seawater 18o reconstructions reveal that monsoon development during the late miocene can be regarded as an abrupt weakening in the easm around 7 5 ma we suggest that an easm weakening was most likely the driving force for decreasing aridity in east and south asia at 8 6 ma leading to widespread ecosystem changes in east and south asia

mount etna dense array local earthquake p and s tomography and implications for volcanic plumbing inversion for the three dimensional velocity structure of mount etna is performed with a data set of arrival times of p and s waves of local earthquakes from temporary dense arrays of three component seismographs a high v p body revealed by the original tomography without nearby stations is confirmed and its image is sharpened using new velocity constraints provided by refraction data synthetic tests of v p and v p v s and comparison with an independent artificial source tomography with a fundamentally different geometry consistently calibrate the significance threshold of the resolution indicators the trustworthy part of the image shows a high v p body centered under the southern part of valle del bove above the 6 km below sea level deep basement which extends towards sea level and may be rooted in or through the crust it has a large contrast of over 1 km s with the surrounding sediments and sharp lateral limits and can thus be regarded as made of intrusive material of magmatic origin the massive high v p body is heterogeneous in v p v s the regions inside it where v s is relatively low can then be suspected of containing a proportion of melt or be fractured and act as pressure links or transport zones such features may be structurally linked and appear to be activated in eruptive phenomena by taking into account the heterogeneities in structure and physical state retrieved by seismic tomography a succession of seismic events deformational episodes and geochemical variation in lavas can be discussed with respect to the well observed eruptions

the coexistence approach theoretical background and practical considerations of using plant fossils for climate quantification the coexistence approach was established by mosbrugger and utescher 1997 as a plant based method to reconstruct palaeoclimate by considering recent climatic distribution ranges of the nearest living relatives of each fossil taxon during its existence for over more than 15 years its basics have been tested and reviewed in comparison with other terrestrial and marine climate reconstruction techniques and climate modelling data however some controversies remain about its underlying data or its applicability in general in view of these controversies this paper discusses the power and limitations of the coexistence approach by summarising past results and new developments we give insights into the details and problems of each step of the application from the assignment of the fossil plant to the most suitable nearest living relative the crucial consideration of the usefulness of specific taxa towards their climatic values and the correct interpretation of the software based suggested palaeoclimatic intervals furthermore we reflect on the fundamental data integrated in the coexistence approach by explaining different concepts and usages of plant distribution information and the advantages and disadvantages of modern climatic maps additionally we elaborate on the importance of continually updating the information incorporated in the database due to new findings in e g palaeo botany meteorology and computer technology finally for a transparent and appropriate use we give certain guidelines for future applications and emphasize to users how to carefully consider and discuss their results we show the coexistence approach to be an adaptive method capable of yielding palaeoclimatic and palaeoenvironmental information through rime and space c 2014 elsevier b v all rights reserved

a new dyke intrusion style for the mount etna may 2008 eruption modelled through continuous tilt and gps data after a recharge phase that began in 2007 on 13 may 2008 a new eruption started on mt etna volcano the final intrusion was very fast accompanied by a violent seismic swarm and marked by ground deformation recorded at permanent tilt and gps stations the violence of the eruptive event generated concern that the eruptive fissures might propagate downslope towards populated areas the ground deformation modelling explains both the mechanism of the intrusion as well as the attempt of the dyke to propagate in the shallower part of the northern sector of the volcano we show that the 2008 intrusion was characterized by a mechanism which is new and different to the ones modelled in previous eruptions following the path of the central conduit in the first part of the intrusion below 1 6 km and then breaking off towards the east in the last shallow part

melt inclusions track pre eruption storage and dehydration of magmas at etna at mount etna italy vigorous gas rich eruptions in a d 2001 2002 and 2003 were followed by gas poor eruptions in 2004 2006 and 2007 analyses of volatile co2 h2o s cl f semivolatile cu and involatile nb la elements trapped in olivine hosted melt inclusions from these latest eruptions reveal the effects of the sustained interaction between a percolating gas phase and the stored magma melt inclusion compositions indicate that magmas erupted from 2004 to 2007 were residual from the 2001 2003 eruptions and show significant evolution in the volatile content of the melt these melt inclusion observations and variations in the c s of volcanic gases can be accounted for if melts reequilibrated with co2 rich gases during storage and prior to entrapment as melt inclusions sustained gas percolation caused loss of water and enhancement of co2 in the evolving melt and may strongly influence the behavior of cu which potentially partitions into the gas phase vapor melt interactions during magma storage are important controls on magma evolution at persistently degassing volcanoes

a new view of the he ar co2 degassing at mid ocean ridges homogeneous composition of magmas from the upper mantle abstract deep sea exploration is rapidly improving our understanding of volatiles geochemistry in mid ocean ridge igneous products it is also placing greater constraints on degassing processes of the earth s mantle with the result that degassing models based on vapour melt equilibrium are no longer able to explain the increasing number of data in fact such models force to postulate an upper mantle strongly heterogeneous at any scale and cannot account for the widespread carbon supersaturation of the recovered igneous products here we review the global he ar co 2 dataset of fluid inclusions in mid ocean ridge glasses using the framework of advanced modelling of multicomponent bubble growth in magmas we display that non equilibrium fractionations among he ar and co 2 driven by their different diffusivities in silicate melts are common in most of the natural conditions of magma decompression and their signature strongly depends on pressure of degassing due to the comparable ar and co 2 diffusivity magma degassing at low pressure fractionates both the he ar and he co 2 ratio by a similar extent while the slower co 2 diffusion at high pressure causes early kinetic effects on ar co 2 ratio and dramatically changes the degassing path on this ground the very different geochemical signatures among suites of data coming from different ridge segments mainly depend on the depth of the magma chamber where the melt was stored besides the variations inside a single suite highlight variable ascent speed and cooling rate of the emplaced lava the large variations in both the he co 2 and ar co 2 ratios at almost constant he ar displayed in glasses coming from the mid atlantic ridge 24 30 n segment and the rodriguez triple junction are therefore interpreted as a high pressure signature in contrast the simultaneous increase in both he co 2 and he ar of the east pacific rise pito seamount and south east indian ridge data sets suggests the dominance of low pressure fractionation implying that the shallow magma chambers are at a lower depth than those of the mid atlantic ridge 24 30 n and rodriguez triple junction our conclusions support the presence of a relationship between spreading rate and depth of high temperature zones below ridges and are consistent with the depth of magma chambers as suggested from seismic studies non equilibrium degassing explains the volatile systematics of mid ocean ridge basalts by starting from a single mantle derived magma dispensing with the supposed need for heterogeneities in abundance ratios of volatiles in the mantle below oceanic ridges

miocene vegetation and climatic changes reconstructed from a sporopollen record of the tianshui basin ne tibetan plateau abstract the miocene vegetation and climate history of western china remains unclear however widely distributed miocene sediments of the tianshui basin in the ne tibetan plateau provide a great potential for deciphering the miocene vegetation and climate history of this region this paper presents first sporopollen record from these sediments covering the period from 17 1 to 6 1 ma sporopollen data reveal that temperate warm temperate broad leaved forest of quercus ulmus and betula dominated the tianshui region between 17 1 and 14 7 ma which was replaced by forest or forest steppe of ulmus artemisia and betula between 14 7 and 11 7 ma after a return to a broad leaved forest of betula and quercus during 11 7 8 5 ma the forest decreased rapidly and was replaced mostly by steppe vegetation mainly composed of artemisia chenopodiaceae and poaceae after 8 5 ma we interpret the observed vegetation changes as a result of global climate change which is characterized by global cooling development of arctic ice sheets and permanent el nino state after the middle miocene climatic optimum the rapid development of steppe at about 8 5 ma suggested a permanent drying of the asian interior at this time coinciding with the onset of the well known hipparion red clay deposition in north china

the cenozoic cooling continental signals from the atlantic and pacific side of eurasia a b s t r a c t the evolution of cenozoic continental climate signals from the atlantic and pacific side of eurasia can be assessed for the first time by comparing climate records obtained for two mid latitudinal regions for the west a detailed climate record over the past 45 ma based on palaeofloras from two northern german cenozoic basins mosbrugger et al 2005 r evealed major trends and shorter term events throughout the cenozoic cooling thus testifying the close correlation of continental and marine temperature evolution as derived from oxygen isotopes zachos et al 2008 using the same methodology we analyze a total of 14 floral horizons originating from continental strata of southern primory e russia in order to study the evolution at the eastern side of the continent the primory e record spans the middle eocene to early pleistocene as the coeval record for the atlantic side it reflects major global signals of cenozoic climate change such as the temperature decline throughout the late eocene coinciding with the growth of antarctic ice sheets warming during the mid miocene climatic optimum and step wise cooling throughout the later neogene the comparison of both records reveals differing regional patterns the considerable longitudinal temperature gradient currently existing between both study areas already began to evolve during the aquitanian and was very significant during the mid miocene climatic optimum the temperature offset between east and west is likely attributable to an effective north atlantic current already operational from the late early miocene onwards bringing about mild winters and low seasonality in western europe while in primory e seasonality steadily increased from the late oligocene on the strong late pliocene decline of cold month mean temperatures recorded in primory e is supposed to coincide with the establishment of the siberian high as semi permanent structure of the northern hemisphere circulation pattern when comparing the precipitation records obtained for both study areas an unexpected co variability at the longer term in the order of 5 20 ma is noted pointing to continent wide hydrological changes the steady decline of mean annual precipitation in the primory e record beginning in the bartonian and culminating in the aquitanian coincides with an aridity increase reported from coeval chinese inland localities of the mid latitudes the seasonality patterns of rainfall point to progressive intensification of the east asian summer monsoon in primory e since the later tortonian while the post zanclean decline of the precipitation of the dry season can be related to an increasing impact of the winter monsoon 2015 elsevier b v all rights reserved

variation of h2o co2 and co2 so2 ratios of volcanic gases discharged by continuous degassing of mount etna volcano italy 1 we applied the multi gas technique to measure compositions of the volcanic plumes continuously discharged from summit craters of voragine northeast and bocca nuova at mount etna in an attempt to estimate compositions of the source volcanic gases the estimated co2 so2 and h2o co2 ratios of the volcanic gases show a large variation ranging from 0 6 to 30 and from 1 to 18 respectively this variability overlaps with the compositional range of dissolved volatiles in melt inclusions and their coexisting bubbles in a magma chamber and can be caused by the low pressure degassing of a magma with variable bubble content ranging from 0 3 to 15 wt the variable bubble content in the magma is likely a result of supply of deep derived co2 rich gas phase to the chamber and subsequent bubble magma differentiation by bubble ascent in the magma chamber in contrast the variation of volcanic gas composition can also be caused by changes of degassing pressure gas magma separation pressure ranging from 0 to 100 mpa as a result of changes in the depth of the top of the convecting magma in volcanic conduits both mechanisms can cause similar compositional variations however the two mechanisms will result in contrasting correlations between the so2 emission rates and the gas compositions that can be examined by parallel observations of the emission rates and compositions in the future

the role of supercritical fluids in the potassium enrichment of magmas at mount etna volcano italy abstract the enrichment in potassium shown by the basic lavas erupted at mount etna volcano after 1971 k2o max 2 2 wt has been considered by previous researchers to be too high to be related to simple crystal fractionation and instead linked this high k2o content to either crustal assimilation or changes in the magma source unfortunately all existing models for the post 1971 k2o enrichment fail to explain the phenomenon satisfactorily leaving the question still open we present a critical re examination of published data for major elements 633 whole rock analyses trace elements 376 whole rock analyses and isotopic ratios 136 87sr 86sr analyses for historical and pre historical lavas potassium enrichment is not limited to the products of the last 35 years a comparable increase in potassium is noticed in lavas erupted during the pre historic phase of the recent mongibello k2o max 2 5 wt and in lavas related to the early phase of the ancient mongibello k2o max 3 wt moreover data from melt inclusions in olivines from the 2001 and 2002 eruptions reveal that potassium contents remain constant for melts with entrapment pressure between 490 to 100 mpa and increase significantly in melts entrapped at pressures below 100 mpa we propose that supercritical fluids coming from deeper magmas and carrying alkali cl complexes migrate through basic to intermediate magmas residing in the shallow feeding system as chlorine exsolves and leaves the system alkalis are released contributing to the observed potassium enrichment of the shallow magma fluctuations of the volatiles influx throughout time are likely related to the magma supply rate considering that the amount of magma entering a plumbing system is determined by the rate of regional extension the flux of alkali cl complexes entering the melt might be related to an extensional regime acting in the etnean area

first 13c 12c isotopic characterisation of volcanic plume co2 we describe analytical details and uncertainty evaluation of a simple technique for the measurement of the carbon isotopic composition of co2 in volcanic plumes data collected at solfatara and vulcano where plumes are fed by fumaroles which are accessible for direct sampling were first used to validate the technique for both volcanoes the plume derived carbon isotopic compositions are in good agreement with the fumarolic compositions thus providing confidence on the method and allowing its application at volcanoes where the volcanic component is inaccessible to direct sampling as a notable example we applied the same method to mount etna where we derived a 13c of volcanic co2 between 0 9 0 27 and 1 41 0 27 bocca nuova and voragine craters the comparison of our measurements to data reported in previous work highlights a temporal trend of systematic increase of 13c values of etna co2 from 4 in the 1970 s and the 1980 s to 1 at the present time 2009 this shift toward more positive 13c values matches a concurrent change in magma composition and an increase in the eruption frequency and energy we discuss such variations in terms of two possible processes magma carbonate assimilation and carbon isotopic fractionation due to magma degassing along the etna plumbing system finally our results highlight potential of systematic measurements of the carbon isotopic composition of the co2 emitted by volcanic plumes for a better understanding of volcanic processes and for improved surveillance of volcanic activity

recent seismicity and tomographic modeling of the mount etna plumbing system the monitoring of seismic activity in eastern sicily southern italy has been recently improved in the framework of the poseidon project to investigate both tectonics and volcanic processes of mount etna this effort has produced a homogeneous and complete data set which we use to image the deep structure of the volcano and to define the space and time distribution of the recent seismicity encompassing the 1995 eruption diffuse eruptions between 1995 and 1997 a further magma intrusion started in 1997 and an increase of volcanic activity in july 1998 we inverted p wave arrival times from 307 selected local earthquakes to obtain a three dimensional velocity model of the volcano with a simultaneous inversion for hypocenters and velocity parameters the new tomographic images permit us to define the structure beneath the volcano from the surface down to 18 km depth the main structural feature revealed by our inversion is a high velocity body located beneath the central craters whose lateral extent increases from 6 km between 18 and 9 km depth to 12 km between 9 and 3 km depth near the surface the fast anomaly branches in two separate high vp regions which are located below the summit craters and the eastern flank valle del bove respectively the high velocity features are interpreted as high density cumulates of solidified magma that intruded the shallow crust we hypothesize that magma ascends the crust within the relatively small high velocity conduit below 9 km depth and is stored at depth shallower than 9 km within the broad high velocity region as also suggested by petrological data a sharp increase of seismicity in 1997 with earthquakes occurring at the border of the high velocity body suggests that mount etna sustained recent episodes of intrusions which possibly herald future eruptions no large low velocity anomaly interpretable as a melted magma chamber is imaged in the upper 18 km of the crust while a broad low velocity anomaly in the uppermost mantle revealed by regional seismic data possibly indicates the magma source region at depth earthquake occurrence from the deep source to the shallow intrusive area helps to trace the magma migration and the feeding of the volcanic system

dating vertebrate microfaunas in the late neogene record of northern china abstract chinese paleontologists have ordered neogene strata in time on the basis of their contained fossils small mammals in particular but biochronology alone attains limited accuracy in a biogeographically restricted system the chronology of terrestrial sediments can be refined when sound systematics of the contained fossils is combined with paleomagnetic data the geomagnetic polarity time scale has proven to be a useful independent reference system for dating the biochronology of continental deposits in north china long composites of successive microfaunas with faunal correlation at times of low endemism and age estimation through paleomagnetic correlation yield robust biochronologies that are well constrained in time the yushe basin shanxi province sequence which has magnetostratigraphic control provides a key reference for the late neogene of north china data from yushe basin identify the microfauna characteristic at the time of the miocene pliocene boundary in northern china the assemblage from near the village of jiayucun strongly resembles the rich microfauna of ertemte inner mongolia and occurs at the base of a reversed magnetozone correlated with chron c3r early gilbert chron latest miocene successive pliocene age assemblages from yushe basin resemble the jingle and youhe local faunas which were formerly used as reference faunas for north china nihewan like assemblages are correlated with the matuyama chron some being pre olduvai subchron and therefore pliocene in age by current definition later pleistocene time is represented in yushe basin by fossil sites in loam deposits the well known loess sequence of central china and other plio pleistocene reference faunas yield a date of ca 1 ma for a reddish loam microfauna from yushe basin

the coexistence approach a method for quantitative reconstructions of tertiary terrestrial palaeoclimate data using plant fossils abstract the coexistence approach is introduced as a method for quantitative terrestrial palaeoclimate reconstructions in the tertiary it is based on the assumption that tertiary plant taxa have similar climatic requirements to their nearest living relatives the aim of the coexistence approach is to find for a given fossil flora and a given climate parameter the climatic interval in which all nearest living relatives of the fossil flora can coexist for this purpose we have developed a data base climbot containing for over 800 tertiary plant taxa the nearest living relatives and their climatic requirements and an algorithm for analysis climst for all types of fossil floras the coexistence approach thus allows the rapid quantitative reconstruction of 10 different climate parameters including the mean annual temperature temperature of the warmest month temperature of the coldest month mean annual precipitation maximum monthly precipitation minimum monthly precipitation precipitation of the warmest month relative humidity potential evaporation as well as the ratio of mean annual precipitation over potential evaporation the reliability and resolution of the coexistence approach are tested with various techniques and proved to be reasonably good for instance the resolution with respect to the mean annual temperature can be up to 1 c applications to various modern and fossil floras are illustrated and the advantages and disadvantages of the coexistence approach are discussed

middle miocene climate and vegetation models and their validation with proxy data abstract the miocene is a relatively recent epoch of the earth s history with warmer climate than today particularly during the middle miocene climatic optimum mmco approximately 17 15 ma although the cause of the warming is probably not only attributable to co2 but also to changes in orography and configuration of ocean gateways this time interval represents an ideal case study to test the ability of climate models to simulate warm climates comparable to those that the earth may experience in the near future however even with higher than present day co2 concentrations the mmco warming inferred from terrestrial proxy data has been difficult to reproduce in climate models since fossil flora do not provide direct information on climate but on flora and vegetation climate model results are generally compared to climate reconstructions obtained from the fossil flora in this study we apply an alternative method by simulating palaeovegetation from the outputs of the climate model using a dynamic vegetation model model vegetation reconstruction can then be compared to the vegetation cover indicated by the fossil flora record at the various localities provided that a common classification of plant functional types pfts is used for the data and the model here we reconstruct the vegetation of the middle miocene with the global dynamic vegetation model caraib using the climatologies derived from five atmospheric general circulation models the reliability of the simulations is examined on a presence absence basis of pfts by comparison of vegetation reconstructions to palaeoflora data recorded in the northern hemisphere and the tropics this comparison provides an overall agreement around 60 between model and data when all sites and tree types are considered three model simulations out of five show to be better at predicting the absence than the presence the presence of warm temperate mixed forests in the middle latitudes dominated by broadleaved deciduous warm temperate and subtropical trees is generally well reproduced in caraib simulations however poor agreement is obtained for the presence of tropical pfts out of the tropics and for warm pfts at latitudes northward of 50 n where climate models remain too cold to produce assemblages of trees consistent with the data nevertheless the model data comparison performed here highlights several mismatches that could result not only from missing feedbacks in the climate simulations but also from the data the results of the likelihood analysis on presence absence of pfts illustrate the uncertainties in the pft classification of the neogene floral records the coexistence of some pfts in the palaeovegetation data is impossible to reproduce in the vegetation model simulations because of the climatic definition of the modern pfts this result indicates either a bias in the identification of modern analogues for fossil plant taxa or a possible evolution of environmental requirements of certain plants

new insights into magma dynamics during last two eruptions of mount etna as inferred by geochemical monitoring from 2002 to 2005 two distinct eruptive events characterize the volcanic activity at mount etna during the 2002 to 2005 period we identified signals of magma ascent preceding these eruptions by geochemical monitoring of both chemical composition and he isotope ratio of gas emissions from five locations in the peripheral area of the volcano the geochemical signals are interpreted using the models proposed by caracausi et al 2003a 2003b and allow identification of episodes of magma ascent and estimation of the pressures of degassing magma as observed for the 2001 eruption caracausi et al 2003b magma ascent probably triggered the onset of the 2002 2003 eruption and minor events of magma ascent were observed between may and december 2003 in contrast to the previous two eruptions the 2004 2005 eruption was not preceded by significant geochemical signals of volcanic unrest suggesting that this eruption was mainly triggered by the failure of the upper portion of the volcanic edifice under the magmatic hydrostatic pressure in the conduits high 3he 4he ratio revealed new volatile rich magma accumulation the 2002 2003 eruption was preceded by a much shorter period of new magma accumulation from deep levels of the feeding system few minor signals of magma migration were detected at some of the sites during the months preceding the 2004 2005 eruption suggesting that the degassed 3he depleted magma resident in the volcanic conduits was not replaced by new volatile rich magma this is in agreement with the lack of explosive activity during the 2004 2005 eruption and with petrologic observations that the parent magma probably erupted in 2000 and 2001 new geochemical signals of magma ascent from the deep reservoir have been identified since june 2005 indicating that the volcanic activity of mount etna is evolving toward new pre eruptive conditions

how old is the asian monsoon system palaeobotanical records from china the recent discovery of monsoon records in early miocene raised a question of the time when the east asian monsoon system initiated a distinguishing feature of the modern monsoon system is its geographic distribution which disturbs the zonal pattern indigenous to the planetary climate system and the appearance of the monsoonal climate pattern in the geological records should signify the onset of the monsoon system here we present the results of a compilation of palaeobotanical and lithological data from 125 sites over china that has revealed two completely different patterns of climate zones the palaeogene pattern with a broad belt of aridity stretched across china from west to east and the neogene pattern with the arid zone restricted to northwest of china which has persisted until today the reorganization of the climate system around the oligocene miocene boundary provides evidence for the establishment of the modern east asian monsoon since then the neogene has witnessed significant variations of the monsoon system including enhancement of aridity and monsoon intensity at about 15 13 my around 8 my and 3 my the new data do not support the onset of the asian monsoon system around 8 my rather the new data led to a hypothesis that the transition to the monsoon climate system in east asia occurred in the latest oligocene

geochemical evidence for mixing between fluids exsolved at different depths in the magmatic system of mt etna italy abstract a 4 year geochemical survey of some fumaroles at the voragine summit crater of mt etna was performed in combination with synchronous monitoring of peripheral gas emissions at the base of the volcano this was the first geochemical study at mt etna to have included the abundances of ar he and c isotopes once the effects of postmagmatic shallow processes were identified and quantitatively removed the he ar co 2 systematics of the voragine crater fumaroles and peripheral gas emissions described the same degassing path combining the carbon isotope composition with information about noble gases provided evidence that the crater fumaroles are fed from a two endmember mixture composed of a deep member coming from pressures between 200 and 400 mpa depending on time and a shallower one exsolved at 130 mpa similar mixing processes probably also occur in gases from peripheral vents the simultaneous assessment of 13 c co2 and he ar values of crater fumaroles over time has identified simple changes in the mixing proportion between the two endmembers and moreover periods during which the exsolution pressure of the deep fluid increased these periods seem to be linked to pre eruptive phases of the volcano the identified open system degassing processes are indicative of efficient bubble melt decoupling at depth whereas the mixing process requires a convective transfer of the deeply exsolved fluids toward shallower levels of magma where further vapor is exsolved in agreement with the most recent geophysical and petrological data from mt etna these observations allow inferences about a deep portion of the plumbing system 5 to 12 km b s l comprising sill like reservoirs connected by small vertical structures and a main reservoir at 2 3 km b s l that is probably fluxed by magmatic volatiles

impacts of tectonic changes on the reorganization of the cenozoic paleoclimatic patterns in china abstract geologic studies have illustrated that the planetary wind dominant climate in the paleogene is changed into the monsoon dominant one near the oligocene miocene boundary in china the evolution is marked by the changes of regional aridity humidity contrasts the contrasts occur between the south and the north part of china in the eocene and then between east china and central asia near the oligocene miocene boundary indicating the onset of monsoon dominant climate in china the impacts of the himalaya tibetan plateau uplift and or the paratethys sea retreat on the asian monsoon have been well demonstrated however whether or not other factors have affected the above reorganization of paleoclimatic patterns remains a question to be addressed additional factors that should be addressed at least include the indian peninsular drift the south china sea expansion and the east china sea transgression here we use the iap agcm to explore their roles in the above paleoclimatic evolution our experiments demonstrate that the south china sea expansion is another major forcing in addition to the important roles of the paratethys retreat and the himalaya tibetan plateau uplift on the contrary the impacts of the indian peninsular drift and the east china sea transgression are relatively subordinate the himalaya tibetan plateau uplift plays a crucial role in the magnification of the aridity humidity contrasts between the south and the north part of china the paratethys retreat the himalaya tibetan plateau uplift and the south china sea expansion coact to cause the formation of the aridity humidity contrasts between east china and central asia the retreat and the uplift favor the dynamic condition and the expansion provides the water vapor condition for the monsoon dominant climate in china

melt inclusion record of the conditions of ascent degassing and extrusion of volatile rich alkali basalt during the powerful 2002 flank eruption of mount etna italy 1 two unusual highly explosive flank eruptions succeeded on mount etna in july august 2001 and in october 2002 to january 2003 raising the possibility of changing magmatic conditions here we decipher the origin and mechanisms of the second eruption from the composition and volatile h2o co2 s cl content of olivine hosted melt inclusions in explosive products from its south flank vents our results demonstrate that powerful lava fountains and ash columns at the eruption onset were sustained by closed system ascent of a batch of primitive volatile rich 4 wt basaltic magma that rose from 10 km depth below sea level bsl and suddenly extruded through 2001 fractures maintained opened by eastward flank spreading this magma the most primitive for 240 years probably represents the alkali rich parental end member responsible for etna lavas evolution since the early 1970s few of it was directly extruded at the eruption onset but its input likely pressurized the shallow plumbing system several weeks before the eruption this latter was subsequently fed by the extrusion and degassing of larger amounts of the same but slightly more evolved magma that were ponding at 6 4 km bsl in agreement with seismic data and with the lack of preeruptive so2 accumulation above the initial depth of sulphur exsolution 3 km bsl we find that while ponding this magma was flushed and dehydrated by a co2 rich gas phase of deeper derivation a process that may commonly affect the plumbing system of etna and other alkali basaltic volcanoes

the middle miocene climatic transition east antarctic ice sheet development deep ocean circulation and global carbon cycling abstract the middle miocene represents a major change in state in cenozoic climatic evolution following the climax of neogene warmth in the late early miocene at 16 ma the early stage of this climatic transition from 16 to 14 8 ma was marked by major short term variations in global climates east antarctic ice sheet eais volume sea level and deep ocean circulation in the later stage from 14 8 to 12 9 ma climatic developments included major growth of the eais and associated antarctic cooling a distinct increase in the meridional temperature gradient large fluctuations in sea level followed by a global sea level fall and important changes in deep water circulation including increased production of southern component water east antarctic ice sheet growth and polar cooling also had large effects on global carbon cycling and on the terrestrial biosphere including aridification of mid latitude continental regions increased stability of the eais after 14 8 ma represents a crucial step in the establishment of late neogene global climate systems what controlled these changes in polar climates and the east antarctic ice sheet deep ocean circulation changes probably played a major role in the evolution and variation in polar climates as they have throughout the cenozoic oxygen and carbon isotopic evidence for warm saline deep water production in the eastern tethyan northern indian ocean indicates that meridional heat transport to the antarctic inhibited cenozoic polar cooling and eais growth during the early middle miocene from 16 to 14 8 ma inferred competition between warm low latitude sources derived from the eastern tethyan northern indian ocean and a cold high latitude source southern component water from 16 to 14 8 ma may have been associated with instability in the antarctic climate and cryosphere reduction of warm saline deep water flow to the southern ocean at 14 8 ma may have decreased meridional heat transport to the antarctic cooling the region and leading to increased production of southern component water these middle miocene climatic and cryospheric changes in the antarctic had profound effects on marine and terrestrial climates as the meridional surface temperature gradient increased boundaries between climatic zones strengthened leading to increased aridification of mid latitude continental regions in australia africa and north and south america enhancing the development of grasslands and stimulating the evolution of grazing mammals

hydrothermal processes governing the geochemistry of the crater fumaroles at mount etna volcano italy article i nfo we investigated the geochemistry of the fumaroles at the summit area of mt etna including sulfur speciation and the content of acidic gases the carbon isotope composition of the etnean plume was also measured in order to compare it to that of fumaroles two types of fumaroles were identified i low temperature fumaroles which are dominated by co2 with minor amounts of so2 and h2s and negligible chlorine contents and ii high temperature fumaroles which are strongly air contaminated and characterized by appreciable amounts of volcanogenic carbon sulfur and chlorine as recognized by martelli et al 2008 both groups of fumaroles are fed by the degassing of an underlying magma nevertheless compositional data clearly show that secondary processes affect the composition of the fluids once they leave the magma body here a model of cooling and condensation of fluids is proposed to explore such postmagmatic processes the model which uses etnean plume geochemistry as starting composition of fluids exsolved from magma shows that so2 and h2s control the redox conditions of the gas mixture during the cooling until the reactions involving co co2 and h2 h2o ratios are fully quenched at temperatures around 350 450 c the dissolution of gases in water subsequent to condensation must occur at thermobaric conditions over 50 bar and 260 c which allows a total removal of hcl b partial removal of sulfur species while preserving the so2 h2s ratio and c the c s ratio to increase by almost 10 fold relative to that in the plume the observed ch4 co2 ratios are higher than those calculated for the etnean magmatic gas and hence they provide evidence of modest contributions from peripheral hydrothermal fluids during the migration of magmatic gases toward the surface in both low and high temperature fumaroles due to the peculiar thermodynamic conditions the model predicts that carbon isotopes do not experience any postmagmatic fractionation and hence the isotopic composition of the fumaroles is representative of magmatic carbon measurements of the carbon isotope composition of the plume corroborate these findings

geochemistry of gases and waters discharged by the mud volcanoes at paterno mt etna italy approximately 20 km south of mt etna craters at the contact between volcanic and sedimentary formations three mud volcanoes discharge co2 rich gases and na cl brines the compositions of gas and liquid phases indicate that they are fed by a hydrothermal system for which temperatures of 100 150 c were estimated by means of both gas and solute geothermometry the hydrothermal system may be associated with co2 rich groundwaters over a large area extending from the central part of etna to the mud volcanoes numerous data on the he ch4 co2 composition of the gases of the three manifestations sampled over the past 5 years indicate clearly that variations are due to separation processes of a co2 rich gas phase from the liquid the effects of these processes have to be taken into account in the interpretation of the monitoring data collected for the geochemical surveillance of etna volcano

roots of etna volcano in faults of great earthquakes abstract results from several seismic methods allow us to sketch the deep structure of etna and its ionian margin under etna a volume of high velocity material is found in a structurally high position the emplacement of this suggests spreading of the surrounding medium just offshore down to the east normal faults penetrate through the upper crust the deeper crustal structure beneath appears upwarped from the basin towards etna juxtaposed with the crust of sicily a thinner crust reaches from the ionian basin under etna and the mantle is upwarped in such a structure magma can then be viewed as a melted lens capping a mantle upwarp at shallow depth rather than in an intracrustal chamber this reduces the conflict between estimates of its volume from excess output of volatiles and short residence times a link in time is indicated between volcanic and seismic activity at a large scale over the millennium the reported ends of episodes of high output rates of magma are followed by the reported occurrences of magnitude 7 earthquakes which caused destruction in southeastern sicily several steep active normal fault have been imaged to a depth of 10 km the crust up to 30 km offshore of the cities of catania and augusta which may be fault planes for such large earthquakes they expand and prolongate the system of the timpe faults on the eastern flank of etna thus linking large scale tectonics offshore with the volcano etna developed together with normal faulting upwarp and spreading during the recent evolution of the former ionian subduction activation of the material at depth at the lateral edge of the slab by vertical motion with extension above could produce the peculiar type of etna magmatism

stable carbon and oxygen isotopic evidence for late cenozoic environmental change in northern china abstract stable carbon and oxygen isotope ratios of 311 enamel samples from a diverse group of herbivorous mammals including equidae rhinocerotidae bovidae rodentia and ochotonidaewere were analyzed in order to reconstruct the late cenozoic history of vegetation and environmental change in the yushe basin in north china the 13c values of bulk and serial enamel samples from large mammals show a wide range of variation from 13 3 to 1 4 with a mean of 7 4 3 5 n 294 this indicates that large herbivorous mammals in the area had a variety of diets since 6 5 ma ranging from pure c3 to mixed c3 c4 and pure c4 diets in contrast the 13c values of small mammals vary from 11 9 to 7 6 with a mean of 9 7 1 1 n 17 indicating that rodents and ochotonids were feeding mostly on c3 plants variations in 13c values within and between species reflect the variations in the habitat and the vegetation consumed by the animals in general horses had higher amounts of c4 grasses in their diets than other contemporary taxa such as bovids rhinos rodents and deer suggesting that horses exploited more open habitats such as grasslands while deer rhinos and rodents may have preferred more c3 vegetation which is more indicative of forested environments the carbon isotope data show that c4 grasses have been an important component of horses diets and of local ecosystems since 6 5 ma confirming that the late miocene c4 expansion occurred in north china as it did in africa indian subcontinent and the americas this supports a global factor as a main driver of the late miocene c4 expansion the combined carbon and oxygen isotope data reveal major shifts in climate to drier and or warmer conditions after 5 8 4 1 3 3 and 2 5 ma and significant shifts to relatively wetter and or cooler conditions after 6 4 5 3 5 ma the shifts to drier and or warmer climate after 5 8 ma and 2 5 ma coincide with two major fauna turnover events intra tooth 13c and 18o values are negatively correlated within individual modern teeth and some fossil teeth displaying the characteristic pattern of the summer monsoon regime and confirming a strong monsoon influence in the area since at least the early pliocene the data also suggest that the c4 abundance in the area has fluctuated over the past 6 5 ma in response to changes in climate with more c4 grasses during warmer and or drier periods and a reduced c4 component at cooler and or wetter times

2001 flank eruption of the alkali and volatile rich primitive basalt responsible for mount etna s evolution in the last three decades abstract since the early 1970s enhanced eruptive activity of mount etna has been accompanied by selective geochemical changes in erupted lavas among which a gradual increase of alkalis whose origin is still debated here we provide further insight into the origin of this recent evolution based on a detailed study of the chemistry and dissolved volatile content of melt inclusions trapped in olivine crystals of unusual plagioclase poor primitive basalt that was extruded during a highly explosive flank eruption in july august 2001 two types of lava were erupted simultaneously along a n s fracture system trachybasalts from the upper vents 2950 2700 m were simply drained out by fracturing of the central volcanic conduit they are identical to summit crater lavas and contain mg poor olivines fo 70 72 with evolved and volatile poor melt inclusions that represent late stage crystallisation during shallow open conduit degassing in contrast plagioclase poor basalt 80 of total extruded through the lower vents 2550 2100 m derived from lateral dyke intrusion of a more primitive and volatile rich magma across the sedimentary basement this primitive melt is best preserved in rare fo 82 4 80 5 skeletal olivines present in lapilli deposits from the most powerful activities at the 2550 m vent its high dissolved contents of h 2 o 3 4 wt co 2 0 11 to 0 41 wt s 0 32 wt cl 0 16 wt and f 0 094 wt point to its closed system ascent from 400 to 250 mpa 12 to 6 5 km depth b s l however the predominance of euhedral olivine phenocrysts with common reverse zoning cores fo 76 78 and rims fo 78 80 and decrepited inclusions shows that most of the erupted basalt derived from a slightly more evolved crystallizing body of the same magma that was invaded by the uprising primitive melt prior to erupting the few preserved inclusions in these olivines indicate pre eruptive storage of that magma body at about 5 km depth b s l in coherence with seismic data we propose that the 2001 flank eruption resulted from gradual overpressuring of etna s shallow plumbing system due to the influx of volatile rich primitive basalt that may have begun several months in advance we find that this basalt is much richer in alkalis 2 0 wt k 2 o and has higher s cl 2 0 but lower cl k and cl f ratios than all pre 1970s etnean lavas 1 4 wt k 2 o s cl 1 5 as further exemplified by melt inclusions in entrained olivine xenocrysts combining these new observations with previously published data we argue that the 2001 basalt represents a new alkali rich basic end member feeding mt etna only few amount of which had previously been extruded during a 1974 peripheral eruption and more recently during brief paroxysmal summit events over the last three decades this new magma has progressively mixed with and replaced the former k poorer trachybasalts filling the plumbing system leading to extrusion of gradually more primitive and alkali richer lavas its geochemical singularities cannot result from shallow crustal contaminations instead they suggest the involvement of an alkali richer but cl poorer arc type component during recent magma genesis beneath etna

geochemical precursors to volcanic activity at mount st helens usa the importance of the interplay between degassing and crystallization before and after the eruption of mount st helens washington usa in 1980 is well established here we show that degassing occurred over a period of decades to days before eruptions and that the manner of degassing as deduced from geochemical signatures within the magma was characteristic of the eruptive style trace element lithium and short lived radioactive isotope lead 210 and radium 226 data show that ascending magma stalled within the conduit leading to the accumulation of volatiles and the formation of lead 210 excesses which signals the presence of degassing magma at depth

sensitivity of east asian monsoon climate to the uplift of the tibetan plateau abstract using the cola center for ocean land atmosphere studies general circulation model a series of numerical experiments were conducted to examine the impact of uplift of the tibetan plateau on the evolution of the monsoon climate in east asia an attempt was made to isolate the effect of the plateau uplift from the changes in other forcing mechanisms we examined the spatial and temporal variation patterns of a variety of climatic variables and indices including monsoon intensity sea level pressure surface and upper air winds temperature at different levels precipitation air humidity and soil moisture our results suggest that the evolution of the east asia monsoon may be more sensitive to the uplift of the tibetan plateau than that of the south asia monsoon moreover the effect of the plateau uplift on the east asia winter monsoon is more significant than that on the summer monsoon in the northern part of east asia north china the formation of the monsoon climate is marked mainly by the establishment of the northerly winds in winter or the winter monsoon system corresponding to the uplift of the plateau when the height reaches approximately 50 of its current elevation on the other hand the establishment of the monsoon climate in the southern part of east asia the yangtze river valley and the area south of it may be much earlier than that in the northern part

correlation of himalayan exhumation rates and asian monsoon intensity although most data suggest that the india eurasia continental collision began 45 55 myr ago the architecture of the himalayan tibetan orogen is dominated by deformational structures developed in the neogene period 23 myr ago the stratigraphic record and thermochronometric data indicate that erosion of the himalaya intensified as this constructional phase began and reached a peak around 15 myr ago it remained high until 10 5 myr ago and subsequently slowed gradually to 3 5 myr ago but then began to increase once again in the late pliocene and pleistocene epochs here we present weathering records from the south china sea bay of bengal and arabian sea that permit asian monsoon climate to be reconstructed back to the earliest neogene these indicate a correlation between the rate of himalayan exhumation as inferred from published thermochronometric data and monsoon intensity over the past 23 myr we interpret this correlation as indicating dynamic coupling between neogene climate and both erosion and deformation in the himalaya although the india eurasia collision initiated 50 myr ago major deformation and exhumation of the himalaya did not begin until the early neogene 23 myr ago this coincides with the increased intensity of the asian monsoons as indicated by weathering records from the south china sea bay of bengal and arabian sea and hints at a dynamic coupling between climate and both erosion and deformation in the himalaya

paleogene temperature gradient seasonal variation and climate evolution of northeast china abstract continental paleogene climates have been well studied in europe and north america but very little is known from asia because paleoclimatic results have only been reported from particular geological intervals here based on 29 plant assemblages from 8 well age controlled fossiliferous sites we quantitatively reconstruct the climates through most of the paleogene of northeast china and discuss related seasonal variations our results demonstrate that the mean annual temperature mat gradient was fairly shallow 0 27 c 1 latitude during the paleocene throughout this region in the eocene seasonality was high in the region indicated by marked differences in both temperature and precipitation between winters and summers of the sites the paleo east asian monsoon must have had intensified at least in the late mid eocene shown by apparent differences in annual precipitation distribution at all the sites regarding the paleogene climatic evolution of northeast china our quantitative results suggest that mat overall declined from warm in the paleocene and eocene to moderate in the oligocene generally consistent with the trend of marine records but with some distinctions two significant cooling events are recognized in the early and mid eocene with mat 3 4 c and 3 8 c lower and winter temperature 5 8 c and 4 7 c lower respectively in similar magnitudes to corresponding variations in europe and north america furthermore the present results show that mat rebounded in the late mid eocene and then decreased until the oligocene a similar pattern demonstrated in europe during the mid eocene to oligocene interval

petrologic evidence of a complex plumbing system feeding the july august 2001 eruption of mt etna sicily italy after the major 1991 1993 eruption mt etna resumed flank activity in july 2001 through a complex system of eruptive fissures cutting the ne and the s flanks of the volcano and feeding effusive activity fire fountains strombolian and minor phreatomagmatic explosions throughout the eruption magmas with different petrography and composition were erupted the vents higher than 2 600 m a s l hereafter upper vents uv erupted porphyritic plagioclase rich trachybasalt typical of present day summit and flank activity differently the vents located at 2 550 and 2 100 m a s l hereafter lower vents lv produced slightly more primitive trachybasalt dominated by large clinopyroxene olivine and uncommon minerals for etna such as amphibole apatite and orthopyroxene and containing siliceous and cognate xenoliths petrologic investigations carried out on samples collected throughout the eruption provided insights into one of the most intriguing aspects of the 2001 activity namely the coeval occurrence of distinct magmas we interpret this evidence as the result of a complex plumbing system it consists in two separate magma storage systems a shallow one feeding the activity of the uv and a deeper and more complex storage related to the activity of lv in this deep storage zone which is thermally and compositionally zoned the favourable conditions allow the crystallization of amphibole and the occurrence of cognate xenoliths representing wall cumulates throughout 2001 eruption uv and lv magmas remain clearly distinct and ascended following different paths ruling out the occurrence of mixing processes between them furthermore integrating the 2001 eruption in the framework of summit activity occurring since 1995 we propose that the 2001 magma feeding the vents lower than 2 600 m a s l is a precursor of a refilling event which reached its peak during the 2002 2003 etna flank eruption

paleoclimatic estimation reveals a weak winter monsoon in southwestern china during the late miocene evidence from plant macrofossils the late miocene xianfeng flora of yunnan province southwestern china was chosen to reconstruct the paleoclimate and the intensity of the asian monsoon three available quantitative climate reconstruction methods from fossil plants i e leaf margin analysis lma the climate leaf analysis multivariate program clamp and the coexistence approach ca were used in this study mats mean annual temperatures resulting from these three approaches i e lma 17 2 2 38 degrees c clamp 15 43 1 25 degrees c ca 17 2 21 7 degrees c appear to have been higher than the present 14 9 degrees c suggesting a much warmer climate in the late miocene both the growing season precipitation gsp from clamp 1908 7 217 7 mm and mean annual precipitation map from ca 1206 0 1613 0 mm estimates are higher than modern values 1003 2 mm gsp and 1038 mm map respectively indicating a more humid climate during the late miocene by comparing these with climates reconstructed from neighboring late miocene floras we conclude that the general late miocene climate appears warmer and more humid than present conditions in southwestern china furthermore the evident differences in estimated monthly temperatures between the summer and winter and precipitations between the humid and dry seasons indicate the existence of seasonality though not as strong as that of today difference in precipitation of dry season indicates a marked strengthening in the winter monsoon since the late miocene a new monsoon intensity index has also been defined based on precipitation seasonality to investigate the intensity of the asian monsoon c 2012 elsevier b v all rights reserved

buoyancy controlled eruption of magmas at mt etna buoyancy controls the ability of magma to rise its ascent rate and the style of the eruptions geophysical geological and petrological data have been integrated to evaluate the buoyancy of magmas at mt etna the density difference between host rocks and magmas is mainly related to the amount of h2o dissolved in the magma and to the bubble liquid separation processes in the depth interval 22 2 km b s l highly hydrated h2o 3 basaltic magmas or mixtures of bubbles liquid have positive buoyancy and rise rapidly conversely bubble depleted liquids with an intermediate h2o content 1 5 having neutral buoyancy will spread out and form magmatic reservoirs at different depths until cooling crystallization further modify composition and density these different processes account for the magma compositions location of magmatic reservoirs as determined by geophysical methods and the complex eruptive cycles slow effusions fire fountains and plinian eruptions that have been observed in the history of the volcano

neogene stratigraphy and paleoenvironments of china abstract neogene deposits are widely distributed in north and west china whereas in southeast china they are confined to isolated basins the neogene in china is predominated by non marine facies and marine deposits are limited to the leizhou peninsula some islands and continental shelves although miocene brackish water deposits were encountered in xinjiang northwest china and a very brief marine transgression took place in north china near the end of the pliocene non marine neogene deposits in china are largely fluvial and lacustrine in origin and composed of mudstones sandstones and conglomerates with local occurrences of lignites and diatomites the maximum thickness may exceed 2000 m e g the qaidam basin a rich fauna and flora have been found in many localities and the most famous are the middle miocene diatomites at shanwang shandong province with unusually well preserved vertebrate and plant fossils a total of 7 mammal stages have been distinguished in china 5 in the miocene 2 in the pliocene and tentatively correlated with the european stages a major realignment of climatic zones occurred before the paleogene neogene boundary when the paleogene climatic zones with a nw trending broad arid zone across the whole of china was eliminated and the arid zone moved to northwest china presumably indicating the onset of the monsoon circulation system during the last few years the marine neogene has been intensively studied in the leizhou peninsula and the three major sedimentary basins off the south china coast the beibu gulf gulf of tonkin basin the zhujiangkou pearl river mouth basin and the yinggehai basin this sequence is over 3000 m thick ranges from the oligocene to the pleistocene and consists of grey mudstones sandstones and conglomerates interbedded with biogenic deposits such as reef limestones and sandy chalk at least 6 foraminiferal assemblages can be recognized in the three basins the psudohastigerina micra assemblage from the oligocene the globigerina ciperoensis cassigerinella chipolensis assemblage from the lower miocene the globoratalia siakensis orbulina suturalis assemblage from the middle miocene the globigerina nepenthes globorotalia acostaensis assemblage from the upper miocene and or lower plicoene the globorotalia tosaensis globigerinoides extremus assemblage from the upper pliocene and the globorotalia truncatulinoides assemblage from the quaternary the nannofossil succession and larger foraminiferal faunas confirm the ages the tropical nature of the neogene faunas is revealed by the occurrences of large foraminifers and warm water species of other groups the transgression cycles are controlled by tectonic processes during the oligocene and early miocene but later by eustatic movements

what controlled mid late miocene long term aridification in central asia global cooling or tibetan plateau uplift a review abstract debate continues over whether global cooling or uplift of the tibetan plateau provided the first order driver for the aridification moisture levels of central asia throughout the mid late miocene between about 17 and 5 ma this review attempts to throw new light on the relations between the aridification and these two key factors this paper examines the evolution of miocene climate both moisture and temperature within five separate regions of eurasia to help understand the large scale controls of long term moisture in central asia the five regions include 1 europe 2 high latitude asia 3 the east asian monsoon region 4 the south asian monsoon region and 5 central asia itself because moisture reaching central asia has to firstly cross at least one of the other four regions temperature proxy data compiled from these five regions correlate with ocean temperatures from the global deep sea oxygen isotope records furthermore compiled moisture proxy data from the four regions surrounding central asia co vary and correlate with each other this can be explained by positive feedbacks between drying and cooling and supports the assumption that global cooling provides a dominant driving factor for the drying of eurasia global cooling reduces the amount of water vapor held in the atmosphere and thereby can cause terrestrial drying however in central asia the moisture evolution shows less similarity with its surroundings the uplift of the tibetan plateau including the tianshan mountains could provide a possible explanation for this difference the changing topography resulting from uplift events over time and space strongly influenced the moisture patterns in central asia during miocene times future research on the spatial timing and amplitude of tibetan plateau uplift should be useful to understand the moisture processes in central asia during the miocene

multiple fluvial styles in late miocene post rift successions of the offshore bohai bay basin china evidence from a seismic geomorphological study abstract during the late miocene river systems exhibiting different planform styles caused accumulation in the post rift offshore bohai bay basin in china these changes in the fluvial style have profound implications for the evolution of the bohai sea shelf and the late miocene monsoon controlled climate using three dimensional 3d seismic data and well and mud logging data seismic and well based fluvial sequence stratigraphic analyses have been untaken the lower minghuazhen member can be subdivided into four fourth order sequences sqm1 to sqm4 each of which contains low and high accommodation systems tracts five fluvial styles including wide trunk incised valleys narrow medium incised tributary valleys medium trunk channels narrow medium low sinuosity channels and narrow high sinuosity channels are recognized based on seismic expressions and well log patterns the seismic geomorphological study of selected stratal slices indicates the temporal change in the fluvial styles from low to high sinuosity channels between last and hast as shift in drainage direction from ssw to see occurs between sqm1 and sqm2 which may be attributed to the lateral migration of the late miocene paleo luan river and the paleo qinglong river that originated from yanshan mountain to the north the development of wide incised braided trunk channels together with some narrow medium incised tributary systems at the base of sqm3 and sqm4 can be interpreted as a response to climate induced enhanced sediment supply in addition the paleoclimate reconstruction based on the palynological analysis reveals that the late miocene fluvial transition from a meandering river to a braided river occurring at sqm3 and sqm4 could be linked to multiple periods of short lived intensification of the east asian summer monsoon easm during the late late miocene within an overall declining trend this might have been conducive to triggering seasonal braided rivers under the higher monsoon rainfall

magma transport through the crust via interconnected sill complexes three dimensional seismic data from the volcanic margin offshore norway have been used to map the complex three dimensional geometry of two major sill complexes these data show that the complexes consist of bowl shaped or inclined sheetlike discordant sills that intersect with one another over a vertical distance of 8 12 km and transect basement and sedimentary rocks of the middle to upper crust using a simple graphical technique we demonstrate the interconnectedness of the sill complex and hence the maximum time for sill emplacement we show that sills are interconnected by junctions occurring systematically at the lowest points of the overlying sills and hence that the sill complex could have acted as a single throughgoing magmatic plumbing system transporting mafic melts from mid lower crustal depths to near surface based on this imaging of the magmatic plumbing system we conclude that sills can form viable and efficient conduits for crustal magma transport in volcanic margins and may play a role in feeding large extrusive complexes

quantitative climate reconstructions of the late miocene xiaolongtan megaflora from yunnan southwest china the late miocene xiaolongtan megaflora from kaiyuan in southeast yunnan 23 degrees 48 45 n 103 degrees 11 52 e 1050 m a s l was chosen for palaeoclimatic reconstruction using three quantitative techniques i e the coexistence approach ca leaf margin analysis lma and the climate leaf analysis multivariate program clamp the reconstructed climatic parameters are also compared with those of the two adjacent miocene floras currently available in yunnan i e the early to middle miocene carpological mangdan flora 24 degrees 24 n 97 degrees 49 e 1620 m a s l and the late miocene luhe palynoflora 25 degrees 10 n 101 degrees 22 e 1930 m a s l quantitative analyses of the xiaolongtan flora supports the previous qualitative results of a southern humid subtropical climate being more humid and having a slightly higher mean annual temperature mat than today the mats calculated by ca lma and clamp overlap 16 7 19 2 degrees c 22 3 2 05 degrees c 18 1 1 2 degrees c respectively and are close to the present day value 19 7 degrees c the overlapping of temperatures derived using the three techniques is unusual and probably related to the low latitude of the xiaolongtan area and the southern subtropical nature of its vegetation both the mean temperatures of the warmest month wmt and of the coldest month cmt reconstructed by ca wmt 25 4 26 0 degrees c cmt 7 7 8 7 degrees c and clamp wmt 25 9 1 6 degrees c cmt 10 8 1 9 degrees c are similar to those of today wmt 24 3 degrees c cmt 12 8 degrees c but great changes appear in the mean annual precipitation map the clamp results suggest a higher precipitation 1964 335 9 mm than ca 1215 1639 mm but they are much higher than the present map 820 5 mm this is consistent with results from the luhe palynoflora which also developed under a warmer subtropical climate with higher precipitation 803 6 1254 7 mm than that of today 815 9 mm in contrast the mangdan flora situated in a more complicated topographic region to the west of xiaolongtan and near the sino myanmar border implies a slightly lower precipitation 1170 1300 mm than that of today 1300 1400 mm overall the wetter climate during the late miocene around the xiaolongtan area suggests that the himalayas had not yet uplifted to its present altitudes at that time c 2009 elsevier b v all rights reserved

the late miocene and pliocene climate in east asia as recorded by grain size and magnetic susceptibility of the red clay deposits chinese loess plateau abstract grain size characteristics of the aeolian red clay sediment series in china demonstrate the existence of warm cool alternations during the late miocene and pliocene from the dissimilarity between the temporal patterns of grain size and magnetic susceptibility it is inferred that the finest grain size fraction in the red clay clay and very fine silt is transported by the wind as is the case of the coarser silty component relatively cool climatic conditions are indicated by increased loess supply represented by the silty component from the nw caused by a stronger winter monsoon as in the overlying quaternary system it is striking that at the same time the amounts of clay also increased probably due to transportation by intensified westerly circulation relatively warm periods are characterized by opposite grain size properties these warm cool alternations on the asian continent dated by palaeomagnetic analyses correlate well with already established changes in sea level and ice sheet volumes up to 6 ma in addition time series analysis of the grain size signal points to an orbitally forced climatic cyclicity precession eccentricity and weak obliquity

forecasting etna eruptions by real time observation of volcanic gas composition it is generally accepted but not experimentally proven that a quantitative prediction of volcanic eruptions is possible from the evaluation of volcanic gas data by discussing the results of two years of real time observation of h2o co2 and so2 in volcanic gases from mount etna volcano we unambiguously demonstrate that increasing co2 so2 ratios can allow detection of the pre eruptive degassing of rising magmas quantitative modeling by the use of a saturation model allows us to relate the pre eruptive increases of the co2 so2 ratio to the refilling of etna s shallow conduits with co2 rich deep reservoir magmas leading to pressurization and triggering of eruption the advent of real time observations of h2o co2 and so2 combined with well constrained models of degassing represents a step forward in eruption forecasting

soil and fumarole gases of mount etna geochemistry and relations with volcanic activity abstract between 1993 and 1996 gas samples were collected on mt etna volcano from both high and low temperature fumaroles and from soils in areas of anomalous degassing located on the flanks of the volcanic edifice the chemical composition of all the emitted gases is consistent with their magmatic origin during their transport to the surface they would undergo shallow mixing processes mostly with air locally as in the case of a point in the lower southwestern flank of the volcano p39 very high contents of he and ch4 indicate that deep gases mainly interact with ground waters and also with a hydrocarbon reservoir the isotopic composition of carbon in co2 from these gases also suggests its primary magmatic origin with inferred 13 c values of magmatic co2 in the range 2 to 1 vs pdb such values significantly more positive than those measured in morbs are in the typical range measured at the other mediterranean volcanoes 5 to 0 more negative values can be explained by shallow interactions between magmatic and organic co2 and or between the former and cold t 120 c ground waters both chemical and isotopic gas geothermometers agree in indicating calculated temperatures ranging from 180 to 270 c for the soil gases collected from low temperature fumaroles near the summit and temperatures around 150 c for the cold gases from p39 thus confirming the presence of a hydrothermal aquifer beneath this point a chemical geothermometer applied on the gases collected from the high temperature fumaroles near the summit craters shows equilibrium temperatures ranging from 385 to 690 c lastly many of the studied parameters showed anomalous variations in time during the studied period the most important of these concerned the flux of co2 through the soil and the concentration of soil h2 which were closely correlated with strong increases in the volcanic activity of etna

late miocene vegetation dynamics under monsoonal climate in southwestern china to better understand vegetation dynamics and the asian monsoonal climate in the neogene we reconstructed the vegetational succession and climate of wenshan basin in southwestern china during the late miocene 11 62 5 33 ma we used newly available palynological data and the results of a quantitative bioclimatic analysis the late miocene palynoflora in wenshan basin resembles that of modern evergreen broadleaf vegetation in subtropical east asia based on pollen elements and reconstructed palaeoclimates in 72 samples we found the composition of the vegetation in the wenshan basin fluctuated during the late miocene and was likely driven by natural climate variability quantitative estimates suggest that the mean annual temperature mat ranged from 16 6 to 17 5 degrees c the mean annual precipitation map was similar to 1500 mm and the monsoon intensity index msi ranged from 11 3 to 17 1 our results indicate that the wenshan basin experienced a warm wet and temperate to subtropical climate by comparison with other late miocene sites in yunnan we show that temperatures differed slightly from region to region and overall annual and seasonal precipitation levels were higher in the late miocene than at present but with a weaker monsoon intensity than in the wenshan basin today c 2015 elsevier b v all rights reserved

carbon dioxide solubility and carbon isotope fractionation in basaltic melt abstract carbon dioxide solubility and isotope fractionation data for a morb composition at 1200 1400 c and 5 20 kbar have been obtained using piston cylinder apparatus and stepped heating mass spectrometry carbon dioxide solubility in basalt melt at 5 10 and 20 kbar is 0 15 0 17 0 45 0 51 and 1 49 respectively values for co 2 vap co 2 3 basalt melt obtained from the difference between the isotopic compositions of coexisting vapour and melt vary from 1 8 to 2 2 a review of measured and estimated values for carbon isotope fractionation between co 2 vapour and carbon dissolved in basic melts shows variation from 1 8 to 4 6 results of this study and other considerations favour relatively small equilibrium co 2 vapour melt fractionation factors around 2

palaeoclimate and vegetation change in serbia during the last 30 ma abstract in the present study 14 published megafloras from the serbian cenozoic are analyzed with respect to vegetation type palaeoclimate and palaeogeographic settings the floras cover a time span from the oligocene to the late miocene the results obtained are compared with continental climate records from other parts of europe and discussed in the context of global climate change to obtain a quantitative palaeoclimate record a total of seven different climate variables is calculated for each of the floras using the coexistence approach it is shown that basic patterns of vegetation change such as the immigration of arcto tertiary deciduous floristic elements during the early miocene and the decreasing diversity of laurophyllous taxa during the late miocene are ruled by climate change and a changing palaeogeography the serbian cenozoic climate record shows a steep cooling gradient during the oligocene that is most probably is connected to a northward movement of tectonic plates the globally observed middle miocene climate optimum and the late miocene cooling are well reflected according to the palaeotemperatures calculated a warm temperate climate existed in serbia throughout the time span examined the late miocene cooling is most pronounced in winter temperatures and is connected to increasing seasonality precipitation rates obtained for the serbian cenozoic especially those of the warmest and wettest months tend to be lower when compared to the central european cenozoic according to climate analysis and the interpretation of vegetational data there is evidence for regionally drier conditions and increased seasonality of precipitation in the time span from the late badenian to the early sarmatian

late miocene vegetation of the pannonian basin abstract the pannonian basin system provides sufficient data to study local and regional vegetation in the context of palaeoclimate and palaeogeography the present study attempts to make use of the latest results in stratigraphy and track vegetation change throughout the late miocene vegetation layers are reconstructed for five time slices from 10 8 ma to 6 5 ma and placed in a palaeogeographic context plant functional types and their distribution frequently applied in ecological studies and biome modelling serve as a tool for reconstructing palaeovegetation units a classification system is introduced considering non zonal elements as well in order to represent the neogene floral record the pft spectra obtained from fossil leaf assemblages indicate the presence of mainly broadleaved deciduous vegetation throughout the regarded time span with variable diversities of conifers and broadleaved evergreen vegetation components during the late miocene the lowland vegetation of the pannonian realm seemed to be more homogeneous than reported in other reconstructions which is in line with the persistence of overall warm and humid climate conditions the existence of distinctly dry periods as partly suggested by other proxies is not supported at the same time data suggest the coeval declining trend of the broadleaved evergreen component in the study area and its final complete disappearance from the north of the pannonian basin in the younger time slices constantly humid conditions might have existed along the northern border of the lake possibly connected to uplift pulses of the alps and carpathians

cenozoic climate gradients in eurasia a palaeo perspective on future climate change abstract recent studies in the frame of the neclime neogene climate evolution in eurasia network provide a comprehensive inventory of continental palaeoclimate data for various time slices reconstructed from the palaeobotanical record the integrative analysis of spatial gradients and patterns observed from the proxy data together with data obtained from numeric modelling studies considerably improved our knowledge about the functioning of the climate system in the cenozoic when compared to the present an overall warmer more humid climate existed cenozoic climates are characterized by warm high latitudes shallow latitudinal and longitudinal gradients and wet continental interiors while concentration of greenhouse gases was about at the present day level or considerably higher thus these past climates potentially are valuable to better understand future climate change because they allow empirical access to climate situations that do not or not yet exist today in the present study continental climate data calculated from micro and macrofloras using the coexistence approach are analysed in order to compare past gradients and patterns and their anomalies relative to present day conditions with future climate change scenarios for the case study three time intervals are selected the mid eocene represents a very warm period of the cenozoic exemplifying greenhouse conditions with high atmospheric co 2 of over 1 100 ppmv the mid miocene is known as outstanding warm time interval as well the concentration of greenhouse gases is still controversially discussed but was certainly below the eocene level a third interval selected the tortonian represents a time span of subsequent cooling with the beginning of arctic glaciation for this period a pre industrial co 2 level is assumed it is shown that the study of past climate patterns provides important clues when evaluating modelling results for future scenarios anomalies predicted under global warming partly coincide with the palaeoclimate data sets as an example for greenhouse conditions the mid eocene data also show a strong warming of the high latitudes and a significant positive anomaly of winter temperatures in the continental interior as in the model study for the future scenario however for the tortonian where a pre industrial co 2 can be assumed data show the best agreement with predicted patterns

quantitative reconstruction of the late miocene monsoon climates of southwest china a case study of the lincang flora from yunnan province the miocene lincang leaf assemblage is used in this paper as proxy data to reconstruct the palaeoclimate of southwestern yunnan sw china and the evolution of monsoon intensity three quantitative methods were chosen for this reconstruction i e leaf margin analysis lma climate leaf analysis multivariate program clamp and the coexistence approach ca these methods however yield inconsistent results particularly for the precipitation as also shown in european and other east asian cenozoic floras the wide range of the reconstructed climatic parameters includes the mean annual temperature mat of 18 5 24 7 degrees c and the mean annual precipitation map of 1213 3711 mm compared with the modem lincang climate mat 17 3 degrees c map 1178 7 mm the miocene climate is slightly warmer wetter and has a higher temperature seasonality a detailed comparison on the palaeoclimatic variables with the coeval late miocene xiaolongtan flora from the eastern part of yunnan allows us to investigate the development and interactions of both south asian and east asian monsoons during the late miocene in southwest china now under strong influence of these monsoon systems our results suggest that the monsoon climate has already been established in southwest yunnan during the late miocene furthermore our results support that both southeast asian and east asian monsoons co occurred in yunnan during the late miocene c 2010 elsevier b v all rights reserved

carbon dioxide transport in crustal magmatic systems abstract the volatile chemistry of juvenile volcanic glasses has suggested that shallow stored crustal magmas often suffer the open system addition of a carbon dioxide rich fluid from below probably from a mantle derived basaltic source carbon dioxide fluxing however the actual mechanism of such a fluid transport is poorly understood to constrain the volatile transport mechanism we formulated this phenomenon as a reactive transport process and clarified the fundamental characteristics of chemical exchange in the system the model assumes that a carbon dioxide rich fluid is introduced into a water rich rhyolitic magma column from below and ascends at a constant velocity whilst a volatile exchange takes place between the fluid and melt two types of exchange modes were examined one is the equilibrium mode where the volatile exchange is instantaneously achieved at all column depths the second is the diffusive mode where the volatile exchange is rate limited by diffusion in the equilibrium mode the extent of re equilibration of the entire column is controlled solely by the mass ratio of the integrated fluid to the melt in the diffusive mode the extent of re equilibration is controlled by the damkohler number a dimensionless parameter representing the ratio of the advection time to the diffusion time when the damkohler number for carbon dioxide exceeds 10 the diffusive exchange becomes indistinguishable from the equilibrium exchange both exchange modes produce a negative correlation between the concentrations of carbon dioxide and water in the melt which cannot be explained by conventional degassing models without significant crystallisation the fluid emitted from the column as a volcanic gas changes its composition from carbon dioxide rich to water rich and the emission rate decreases monotonically during fluxing the simulation enables us to constrain the mechanism of fluid transport for the melt inclusion data from the bishop tuff wallace et al 1999 anderson et al 2000 fluid velocity in this magma was estimated to be 10 6 10 7 m s the corresponding mechanism of fluid transport may include permeable flow with a permeability of 10 15 m 2 or a buoyant ascent of individual bubbles with a radius of 4 7 mm

patterns in the recent 2007 2008 activity of mount etna volcano investigated by integrated geophysical and geochemical observations 1 seismic deformation and volcanic gas observations offer independent and complementary information on the activity state and dynamics of quiescent and eruptive volcanoes and thus all contribute to volcanic risk assessment in spite of their wide use there have been only a few efforts to systematically integrate and compare the results of these different monitoring techniques here we combine seismic volcanic tremor and long period seismicity deformation gps and geochemical volcanic gas plume co2 so2 ratios measurements in an attempt to interpret trends in the recent 2007 2008 activity of etna volcano we show that each eruptive episode occurring at the southeast crater sec was preceded by a cyclic phase of increase decrease of plume co2 so2 ratios and by inflation of the volcano s summit captured by the gps network these observations are interpreted as reflecting the persistent supply of co2 rich gas bubbles and eventually more primitive magmas to a shallow depth of 1 2 8 km asl magma storage zone below the volcano s central craters ccs overpressuring of the resident magma stored in the upper ccs conduit triggers further magma ascent and finally eruption at sec a process which we capture as an abrupt increase in tremor amplitude an upward 2800 m asl and eastward migration of the source location of seismic tremor and a rapid contraction of the volcano s summit resumption of volcanic activity at sec was also systematically anticipated by declining plume co2 so2 ratios consistent with magma degassing being diverted from the central conduit area toward sec

onset of asian desertification by 22 myr ago inferred from loess deposits in china the initial desertification in the asian interior is thought to be one of the most prominent climate changes in the northern hemisphere during the cenozoic era1 2 3 4 but the dating of this transition is uncertain partly because desert sediments are usually scattered discontinuous and difficult to date here we report nearly continuous aeolian deposits covering the interval from 22 to 6 2 million years ago on the basis of palaeomagnetic measurements and fossil evidence a total of 231 visually definable aeolian layers occur as brownish loesses interbedded with reddish soils this new evidence indicates that large source areas of aeolian dust and energetic winter monsoon winds to transport the material must have existed in the interior of asia by the early miocene epoch at least 14 million years earlier than previously thought3 5 regional tectonic changes and ongoing global cooling are probable causes of these changes in aridity and circulation in asia

a lancefieldian graptolite from the lake district large dictyonema species including d pulchellum t s hall have been collected from beds in the uldale fells northern lake district below strata yielding didymograptus protobalticus monsen they suggest the presence there of graptolitic beds transitional from lancefieldian to bendigonian in age approximately tremadoc arenig and suggest that the area may yet provide an internationally correlatable base to the arenig series in britain

evolution and variability of the asian monsoon system state of the art and outstanding issues the asian monsoon is comprised of the indian and east asian subsystems these two components are linked to one another in varying degrees by regions of strong sensible heating indo asian landmass and strong latent heat export the western pacific warm pool and the southern subtropical indian ocean variability within the indian and east asian subsystems interactions among them and the extent to which they interact with other climate phenomena e g enso are current topics of modern and paleoclimate research this work provides an overview of past and current paleomonsoon research on tectonic to interannual time scales with a primary focus on marine sediment records while past and current work has contributed greatly to our understanding of paleomonsoon variability at all time scales additional efforts are required to make further progress in two critical areas 1 additional efforts are needed in terms of proxy development and evaluation requiring concerted efforts at long term sediment trap deployments in key monsoon influenced regions as well as development of adequate and widely available core top databases these are necessary to assess the impact of modern oceanographic and seafloor processes on potential monsoon proxies 2 additional effort is also needed in acquiring a sufficient geographic distribution of downcore records to assess linkages among the subsystems and their role in the context of extratropical climate change these records should have high sedimentation rates including varved sections this requires substantial survey support to identify the most appropriate coring and drilling targets c 2004 elsevier ltd all rights reserved