the llamas de cabrera gold district a new discovery in the variscan basement of northwest spain a fluid inclusion and stable isotope study the northwest of the iberian massif is well known to host numerous gold mineralizations which were exploited during roman times this study presents a multidisciplinary approach leading to the mineralogical fluid inclusions and geochemical characterization of the recently rediscovered roman gold district of llamas de cabrera gold occurs in extensional quartz veins hosted in the upper layers of the lower to middle ordovician armorican quartzite and occasionally in the overlaying middle ordovician slates from luarca formation the veins are characterized by multistage ore deposition developed along three hydrothermal stages as fe i as fe ii and au zn cu pb followed by late supergene alteration processes the fluid inclusion study undertaken on mineralized quartz revealed the presence of three types of fluids 1 co2 ch4 fluid inclusions 2 aqueous carbonic fluid inclusions dominated by co2 and subordinate ch4 related to quartz arsenopyrite pyrite deposition and 3 aqueous fluid inclusions related to the au sulfide deposition in conjunction with arsenopyrite geothermometry and fluid inclusion data an attempt was made to determine the p t conditions of ore formation changes occurred in the p t conditions fromarsenopyrite and pyrite deposition in quartz veins from aqueous carbonic fluids at 300 390 c and 200 220 mpa towards 180 310 c and b200 mpa at the stage of gold from aqueous fluids mixing of two aqueous fluids of relatively contrasted salinity were favorable factors for decreasing gold solubility and could allow gold deposition the 34s values are similar for the two as fe stages 8 0 to 16 3 and 9 0 to 19 5 respectively and for the post s1 pyrites from siliciclastic luarca formation suggesting a comparable sulfur source combining calculated 18o values of fluids of 6 7 to 9 4 with fluid inclusion data indicates that fluids of unknown origin are largely equilibrated withmetamorphic lithologies at medium high temperatures the ascent of some late variscan magmatic bodies not exposed at the present day erosion level provides the heat source for convective water circulation gold quartz veins from llamas de cabrera display similar features and processes to related deposits of similar type elsewhere in the variscan belt of western europe northwest and central western iberia french massif central bohemianmassif however llamas de cabrera shows certain differences such as the non appearance of igneous rocks in the area and the absence of sb rich minerals compared to some variscan sb au deposits including northern central and western iberia this last could probably be due to a greater depth of formation for the as au veins in comparison to sb au veins

discriminating fluid source regions in orogenic gold deposits using b isotopes abstract the genesis of orogenic gold deposits is commonly linked to hydrothermal ore fluids derived from metamorphic devolatilization reactions however there is considerable debate as to the ultimate source of these fluids and the metals they transport tourmaline is a common gangue mineral in orogenic gold deposits it is stable over a very wide p t range demonstrates limited volume diffusion of major and trace elements and is the main host of b in most rock types we have used texturally resolved b isotope analysis by secondary ion mass spectrometry sims to identify multiple fluid sources within a single orogenic gold ore district the loulo mining district in mali west africa hosts several large orogenic gold ore bodies with complex fluid chemistry associated with widespread pre ore na and multi stage b metasomatism the gara deposit as well as several smaller satellites formed through partial mixing between a dilute aqueous carbonic fluid and a hypersaline brine hydrothermal tourmaline occurs as a pre ore phase in the matrix of tourmalinite units which host mineralization in several ore bodies clasts of these tourmalinites occur in mineralized breccias disseminated hydrothermal and vein hosted tourmaline occur in textural sites which suggest growth during and after ore formation tourmalines show a large range in 11 b values from 3 5 to 19 8 which record a change in fluid source between paragenetic stages of tourmaline growth pre mineralization tourmaline crystals show heavy 11 b values 8 19 8 and high x site occupancy na ca 0 69 1 apfu suggesting a marine evaporite source for hydrothermal fluids syn mineralization and replacement phases show lighter 11 b values 3 5 to 15 1 and lower x site occupancy 0 62 0 88 apfu suggesting a subsequent influx of more dilute fluids derived from devolatilization of marine carbonates and clastic metasediments the large overlapping range in isotopic compositions and a skew toward the opposing population in the 11 b data for both tourmaline groups reflects continual tourmaline growth throughout mineralization which records the process of fluid mixing a peak in 11 b values at 8 largely controlled by tourmalines of syn to post ore timing represents a mixture of the two isotopically distinct fluids this paper demonstrates that b isotopes in tourmaline can be instrumental in interpreting complex and dynamic hydrothermal systems the importance of b as an integral constituent of orogenic ore forming fluids and as a gangue phase in orogenic gold deposits makes b isotope analysis a powerful tool for testing the level of source region variability in these fluids and by extension that of metal sources

syndeformational fluid trapping in quartz determining the pressure temperature conditions of deformation from fluid inclusions and the formation of pure co2fluid inclusions during grain boundary migration observations and microthermometric data on fluid inclusions from a terrane that underwent deformation following peak metamorphic conditions show that grain boundary migration recrystallization favours the entrapment of carbonic inclusions whereas microfracturing during brittle deformation favours the infiltration and eventual entrapment of aqueous fluids our results imply that pure co2 fluid inclusions in metamorphic rocks are likely to be the residue of deformation recrystallization process rather than representing a primary metamorphic fluid where the temperature of deformation can be deduced by other means the densities of fluid inclusions trapped during recrystallization which we call recrystallization primary fluid inclusions can be used to constrain the ambient pressure during deformation using these constraints the data imply that the post metamorphic hercynian exhumation in sardinia brought rocks at 300 c to within 3km of the surface this conclusion is similar to that described for the rapidly uplifted southern alps in new zealand

the presence of carbonic dominant volatiles during the crystallization of sulfide bearing mafic pegmatites in the north roby zone lac des iles complex ontario mafic pegmatites in the platinum group element pge mineralized roby zone lac des iles complex northwest ontario canada comprise dikes veins and irregular pods of coarse grained magnesiohornblende pyroxene and labradorite andesine with minor biotite apatite fe ti oxides and intercumulus quartz that grades into massive quartz or graphic quartz base metal sulfide vysotskite pd ni s intergrowth at their cores quartz apatite and magnesiohornblende host primary and secondary assemblages of one or two phase carbonic fluid co 2 up to 10 ch 4 minor h 2 o n 2 inclusions that contain ore metals ni cu pd bi te fe rare trails of late stage high salinity aqueous fluid inclusions are secondary in origin and therefore unrelated to the crystallization of the pegmatites assemblages of primary carbonic fluid inclusions show considerable variation in mode and temperature of homogenization reflecting large fluctuations in confining pressure at the time of quartz crystallization of as much as 1 kbar in single quartz crystals and 2 8 kbars all data independent thermobarometric methods constrain conditions for the following two stages of pegmatite formation and carbonic fluid entrapment 1 the crystallization of magnesiohornblende plagioclase intergrowth at t 650 to 850 c and p 1 to 3 kbars and 2 the crystallization of quartz at t 535 to 650 c and p 0 4 to 3 2 kbars setting the maximum depth of emplacement of the lac des iles complex north roby zone magma at 10 to 12 km the results indicate that aqueous dominant volatile phases were absent during the crystallization of pegmatitic gabbroic rocks at the lac des iles complex and that water poor carbonic fluid entrapment persisted to well below solidus conditions a role played by carbonic fluid as a potential transport medium for ligands involved in the precipitation and remobilization of the pge and base metals is strongly suggested and warrants further investigation

statistical microthermometry of synthetic fluid inclusions in quartz during decompression reequilibration fluid inclusion microthermometric data are often reported as homogenization temperature frequency histograms interpretation of such histograms for a single fluid inclusion assemblage fia of non reequilibrated fluid inclusions is usually straightforward and provides an accurate determination of the original density th of that fia however interpretation of such histograms for reequilibrated inclusions is more problematic decompression experiments using synthetic inclusions in natural quartz and conducted at 2 5 kbar and 600 700 c with a maximum internal overpressure of 2 kbar indicate that histogram shape reflects the sample s p t history our results further indicate that the mean mode range standard deviation extreme values etc all have a significance with respect to the p t history of the sample thus a mound shaped unimodal histogram with low range is indicative of a nearly isochoric cooling p t path a unimodal histogram that is slightly skewed to the right and with a low standard deviation but high range results from inclusion deformation in the plastic regime high temperature low strain rates fluid inclusions deformed plastically show no correlation between size and density histogram outliers should not be ignored and may be used to determine an isochore that passes close to the conditions of entrapment minimum th or close to the final reequilibration conditions maximum th the histogram mean th value corresponds to an isochore that represents the internal overpressure about 1 kbar that can be maintained over geologic time by a majority of reequilibrated fluid inclusions a multimodal histogram with high range and high standard deviation indicates inclusion brittle deformation low temperature high strain environments fluid inclusions deformed in a brittle manner show strong positive correlation between size and density histograms produced in the laboratory show many similarities to histograms for natural samples offering the hope that laboratory results may be used to interpret p t histories of natural samples

comparison of lignin phenols and branched isoprenoid tetraethers bit index as indices of terrestrial organic matter in doubtful sound fiordland new zealand abstract the branched isoprenoid tetraether bit index has recently been proposed as a qualitative proxy for the relative amounts of soil and marine derived organic matter om in marine sediments we compare bit values with lignin phenol cuo oxidation products and bulk om proxies in surface sediment samples from doubtful sound a fjord in the southwestern end of new zealand s south island as well as in soils and leaf litter from the local pristine temperate rainforest watershed the region has extreme rates of annual rainfall 7 m year 1 and large mass wasting soil and vegetation events on fjord slopes which results in relatively high fluxes of terrestrial organic matter om terr to fjord sediments sediments contained up to 11 4 w w organic carbon oc with terrestrial to a mixture of terrestrial marine 13 c 24 3 to 28 7 and c n 14 7 36 8 signatures bit values ranged from 0 24 to 0 93 lignin abundance in sediments reported as 8 values mg 8 lignin phenols 100 mg oc 1 ranged from 2 7 to 11 2 a weak correlation was found between concentrations of lignin phenols and bit values r 2 0 313 the likely cause of the differences between the two proxies is differences in the relative amounts of soil om om soil and vegetation intact and detrital transported to the fjord by episodic mass wasting events and gradual accumulation from overland leaching by rainfall and riverine sources interestingly the bit index correlated significantly with bulk sedimentary om om sed proxies 13 c r 2 0 774 c n r 2 0 629 while lignin phenol values 8 exhibited a much weaker correlation with 13 c values r 2 0 320 and no correlation with c n values r 2 0 005 this suggests that om soil represents the dominant fraction of om terr delivered to fjord sediments

oceanic propagation of a potential tsunami from the la palma island 1 the likelihood of a large scale tsunami from the la palma island is considered small by most nevertheless the potential catastrophic consequences call for attention here we report on numerical simulations of a tsunami that might result from the extreme case of a flank collapse of the cumbre vieja volcano at the la palma island done by combining a multimaterial model for the wave generation with boussinesq models for the far field propagation our simulations show that the slide speed is close to critical effectively generating an initial wave of several hundred meters height our main focus is the wave propagation which is genuinely dispersive in the far field propagation becomes increasingly complex due to the combined effects of dispersion refraction and interference in the direction of propagation constructive interference of the trailing waves are found to decrease the decay of the maximum amplitude with distance compared to classical asymptotic theory at transatlantic distances thus the commonly used hydrostatic models fail to describe the propagation consequences of the la palma scenario would be largest at the canary islands but our findings also suggests that the whole central atlantic would face grave consequences however the largest surface elevations are smaller than the most pessimistic reports found in literature we also find undular bores towards the shorelines of america

morphology of fore reef slopes and terraces takapoto atoll tuamotu archipelago french polynesia central pacific the tectonic sea level and coral growth control abstract a dataset of 41 bathymetric profiles detected by satelline imagery and echo sounding to a maximum depth of 38 m along the fore reef slopes of takapoto atoll tuamotu plateau french polynesia central pacific were qualitatively and quantitatively analyzed in order to identify the main geomorphological features in addition scuba diving investigations from a selected site resulted in defining coral composition and cover rate six distinct fore reef sectors were morphologically differentiated on the basis of seaward extension and slope gradient only the north end and a restricted area of the mid south east side extend seawards over an average distance of 150 m with a relatively low gradient 23 38 most of the outer slope areas are narrow 10 m high outer reef crest like reliefs 0 5 m 1 5 m high pinnacles 2 m 17 m high coral heads

fluid inclusion studies of the abawso gold prospect near the ashanti belt ghana the major ghanaian lode gold deposits are preferentially aligned along the western and eastern contacts of the kumasi basin with the ashanti and sefwi belts respectively the investigated area of the abawso small scale concession covering the workings of the old ettadom mine is situated 3 km west of the lithological contact of the birimian metavolcanic rocks of the akropong belt in the east with the birimian metasedimentary rocks of the kumasi basin in the west the rocks of the abawso concession represent a steeply nw dipping limb of a se verging anticline with an axis plunging to the sw quartz veining occurs predominantly in the form of en echelon dilatational veins along nne ssw striking shear zones of a few metres width and shows evidence of brittle and ductile deformation also stockwork style quartz veining occurs in the vicinity of the main shaft of the old ettadom mine hydrothermal alteration includes sericitisation sulphidation and locally carbonatisation the auriferous quartz veins mainly follow the trend of brittle to ductile deformed quartz veins however some occur in stockwork fluid inclusion studies reveal a large number of h2o inclusions along intragranular trails in auriferous quartz vein samples as well as an overall dominance of h2o and h2o co2 inclusions over co2 inclusions textural observations and physico chemical fluid inclusion properties indicate post entrapment modifications for all quartz vein samples due to grain boundary migration recrystallisation this process is interpreted to be responsible for the generation of the co2 inclusions from a h2o co2 parent fluid in comparison with mineralisation at the ashanti and prestea deposits which are characterised by co2 n2 inclusions the observed inclusion assemblage may be due to a shallower crustal level of mineralisation or different degrees and styles of recrystallisation or a less pronounced development of laminated quartz veins due to comparably restricted pressure fluctuations furthermore the microthermometric observations allow the reconstruction of a possible retrograde p t path depicting near isothermal decompression in the p t range of the brittle ductile transition

origin of the co2 only fluid inclusions in the palaeoproterozoic carara vein quartz gold deposit ipitinga auriferous district se guiana shield brazil implications for orogenic gold mineralisation abstract the carara gold deposit located in the ipitinga auriferous district south eastern portion of the guiana shield northern brazil is a typical orogenic greenstone hosted auriferous quartz vein mineralisation was post metamorphic and syn tectonic in relation to the host palaeoproterozoic ca 2 03 ga shear zone developed close to the tectonic boundary between a palaeoproterozoic continental arc and an archaean block the deposit style is very simple consisting of a quartz vein and its hydrothermal envelope which is composed of muscovite and tourmaline sulphides are rare muscovite and tourmaline in addition to gold fill small fractures in the quartz vein the fluid inclusion assemblage trapped in high and low grade portions of the au quartz vein is rather enigmatic consisting of one phase co 2 inclusions with no visible water at room or sub zero temperatures although small amounts of water have been detected by micro raman analysis in this aspect carara differs from the other gold showings in the same district which are characterized by abundant aqueous carbonic fluid inclusions the carbonic fluid is composed predominantly of co 2 in addition to 2 and traces of ch 4 and c 2 h 6 the carbonic fluid show very variable densities which is interpreted to result from post entrapment re equilibration inclusions in the high grade quartz are the densest 0 89 to 1 07 g cm 3 and with less effects of re equilibration these inclusions approximate the physico chemical characteristics of the parental fluid that started to be trapped at least around the amphibolite facies metamorphic conditions and then followed a retrograde path most of the inclusions appear to have been trapped and or re equilibrated at 350 to 475 c and 1 8 to 3 6 kbar which implies a 7 to 12 km depth of vein formation and gold mineralisation both phase separation of a carbonic aqueous fluid x co 2 0 8 and the existence of an originally co 2 dominated fluid could account for the observed fluid inclusion properties and the absence of h 2 o bearing inclusions in the mineralised vein the fluid inclusion characteristics combined with published geological and isotopic information indicate a deep seated source for co 2 that could be mantle magmatic or metamorphic in origin we suggest that the likely sources are fluid produced by the 2 07 ga old charnockites that occur in the region and or the coeval high grade metamorphism that is widespread in the guiana shield

twin tsunamis triggered by the 12 january 2010 haiti earthquake on 12 january 2010 a magnitude m w 7 0 earthquake occurred 25 km west southwest of haiti s capital port au prince causing an estimated 316 000 fatalities thereby exceeding any previous loss of life from a similar size earthquake in addition tsunami waves triggered by the earthquake caused at least three fatalities at petit paradis due to a complete lack of tsunami awareness the international tsunami survey team itst was deployed within weeks of the event and covered the greater bay of port au prince and more than 100 km of hispaniola s southern coastline the collected survey data include more than 21 tsunami heights along with observations of coastal land level change maximum tsunami heights of 3 m have been measured for two independently triggered tsunamis

fluid evolution and chemical controls in the fazenda maria preta fmp gold deposit rio itapicuru greenstone belt bahia brazil the fazenda maria preta fmp gold deposit is confined to two regional scale sinistral oblique brittle ductile shear zones which are located in a greenschist facies metamorphosed volcano sedimentary sequence in the northern sector of the lower proterozic rio itapicuru greenstone belt ne brazil alteration is pervasive throughout the shear zones and characterized by carbonatization and sericitization of intermediate volcanic volcaniclastic and sub volcanic rocks the orebodies are mainly shear veins hosted by or directly associated with highly deformed carbonaceous volcaniclastic rocks breccia and stockwork systems or disseminations in felsic and mafic sub volcanic bodies native gold appears as free grains finely disseminated in the quartz veins or closely related to arsenopyrite pyrite pyrrhotite sphalerite and fe chlorite in the carbonaceous wallrocks fluid inclusion studies by microthermometry and laser raman microspectroscopy revealed that the vein quartz is largely dominated by primary pseudosecondary and rarely secondary populations of co2 ch4 n2 inclusions type i whereas primary groups of low salinity 6 wt eq nacl h2o co2 ch4 n2 inclusions type ii comprise the dominant inclusion type in only a few veins the thco2 l v l data indicated a variation in the co2 density of 1 05 to 0 60 g cm3 for the type i inclusions and conversely a narrower range of 0 76 0 73 g cm3 for the type ii inclusions the broader variation of the co2 density for the co2 rich fluid could have been the result of trapping of the vein fluid under a variable pressure regime or by its re equilibration during continuous deformation within the shear zone domains and reduction of the overburden pressure during uplift the co2 rich fluid inclusions provide no evidence that they have been the result of h2o loss either during infiltration e g hydration reactions or after trapping of an original h2o co2 fluid accordingly the co2 ch4 n2 and the h2o co2 ch4 n2 fluids are considered as representatives of two distinct fluid regimes which were active during the gold mineralizing events within the shear zones both types of ore fluids are interpreted as part of a deep metamorphic magmatic hydrothermal system in which i a co2 rich fluid probably originated in the mantle was transported to and released in higher structural levels mainly by tonalitic granodioritic and alkaline magmas whereas ii a h2o co2 fluid generated by devolatilization reactions during the regional metamorphism was either directly channeled into favorable structural sites i e metamorphic fluid or absorbed and later exsolved by the crystallization of felsic magmas i e magmatic fluid sensu lato in this context gold deposition occurred between 320 c and 420 c and 2 1 to 4 4 kb and calculated values of fo2 between 10 26 5 and 10 32 4 bar reveal the relatively reducing nature of the mineralizing fluids the ore paragenesis constrains fs2 to the range of 10 10 1 10 6 5 bar for these fluids under such conditions the gold was transported mainly as bisulfide complexes by the h2o co2 fluid but in the case of the co2 rich fluid the role of thiocomplexes or some other types of ligands is obscured by the lack of high temperature experimental data deposition of the metal occurred in response to redox changes which accompanied fluid carbon interaction particularly a decrease in fo2 and fs2 of the fluid on a microscopic scale phisisorption and chemisorption processes at the fluid iron sulfide interface may have further enhanced the deposition of the gold particularly on the surfaces of precipitating pyrite and arsenopyrite

high co2 content of fluid inclusions in gold mineralisations in the ashanti belt ghana a new category of ore forming fluids a reply fluid inclusions were studied in samples from the ashanti konongo southern cross prestea abosso damang and ayanfuri gold deposits in the ashanti belt ghana primary fluid inclusions in quartz from mineralised veins of the ashanti prestea konongo southern cross and abosso damang deposits contain almost exclusively volatile species the primary setting of the gaseous i e the fluid components co2 ch4 and n2 fluid inclusions in clusters and intragranular trails suggests that they represent the mineralising fluids microthermometric and raman spectroscopic analyses of the inclusions revealed a co2 dominated fluid with variable contents of n2 and traces of ch4 water content of most inclusions is below the detection limits of the respective methods used aqueous inclusions are rare in all samples with the exception of those from the granite hosted ayanfuri mineralisation here inclusions associated with the gold mineralisation contain a low salinity co2 and low salinity 6 eq wt nacl however fluid inclusions in quartz from the gold mineralisations in the ashanti belt point to distinctly different fluid compositions specifically the predominance of co2 and co2 h2o have to be emphasized fluid systems with this unique bulk composition were apparently active over more than 200 km along strike of the ashanti belt fluids rich in co2 may present a hitherto unrecognised new category of ore forming fluids

numerical modeling of tsunami waves generated by the flank collapse of the cumbre vieja volcano la palma canary islands tsunami source and near field effects 1 in this work we study waves generated by the potential collapse of the west flank of the cumbre vieja volcano cvv la palma canary island spain through numerical simulations performed in two stages i the initial slide motion and resulting free surface elevation are first calculated using a 3d navier stokes model ii generated waves are then input into a 2d horizontal boussinesq model to further simulate propagation to the nearby islands unlike in earlier work on cvv besides a similar extreme slide volume scenario of 450 km3 in our simulations i we consider several slide scenarios featuring different volumes i e 20 40 80 km3 which partly result from a geotechnical slope stability analysis ii we use a more accurate bathymetry and iii an incompressible version of a multiple fluid material navier stokes model we find wave trains for each scenario share common features in terms of wave directivity frequency and time evolution but maximum elevations near cvv significantly differ ranging from 600 to 1200 m for increasing slide volume additionally our computations show that significant energy transfer from slide to waves only lasts for a short duration order 200 s which justifies concentrating our best modeling efforts on the early slide motion phase the anticipated consequences of such wave trains on la palma and other canary islands are assessed in detail in the paper

a novel proxy for terrestrial organic matter in sediments based on branched and isoprenoid tetraether lipids we propose a novel tracer for terrestrial organic carbon in sediments based on the analysis of tetraether lipids using high performance liquid chromatography mass spectrometry hplc ms analysis of terrestrial soil and peats shows that branched tetraether lipids are predominant in terrestrial environments in contrast to crenarchaeol the characteristic membrane lipid of non thermophilic crenarchaeota which is especially abundant in the marine and lacustrine environment based on these findings an index was developed the so called branched and isoprenoid tetraether bit index based on the relative abundance of terrestrially derived tetraether lipids versus crenarchaeol this bit index was applied to surface sediments from the angola basin where it was shown to trace the outflow of the congo river furthermore analyses of particulate organic matter from the north sea showed relatively higher bit indices in water column particulate organic matter near large river inputs a survey of globally distributed marine and lacustrine surface sediments shows that the bit index in these environments correlates with the relative fluvial input of terrestrial organic material making this index generally applicable the new proxy allows the rapid assessment of the fluvial input of terrestrial organic material in immature sediments up to 100 ma old

the december 22 2018 anak krakatau indonesia landslide and tsunami preliminary modeling results on the evening of december 22 2018 the coasts of the sunda strait indonesia were hit by a tsunami generated by the collapse of a part of the anak krakatau volcano hundreds of people were killed thousands were injured and displaced this paper presents a preliminary modeling of the volcano flank collapse and the tsunami generated based on the results of a 2d depth averaged coupled model involving a granular rheology and a coulomb friction for the slide description and dispersive effects for the water flow part with a reconstructed total volume subaerial and submarine of the landslide of 150 million hbox m 3 inferred from pre and post collapse satellite and aerial images the comparison of the simulated water waves with the observations tide gauges located all around the strait photographs and field surveys is satisfactory due to the lack of information for the submarine part of the landslide the reconstructed submarine slope is assumed to be approximately constant a significant time delay on the results and particularly in the bandar lampung bay could be attributed to imprecisions of bathymetric data the sensitivity to the basal friction and to dispersive effects is analyzed through numerical tests results show that the influence of the basal friction angle on the simulated wave heights decreases with distance and that a value of 2 circ gives consistent results with the observations the dispersive effects are assessed by comparing water waves simulated by a shallow water model and a boussinesq model simulations with frequency dispersion produce longer wave periods and smaller wave amplitudes in the sunda strait and particularly in deep waters

dense water production on the northern okhotsk shelves comparison of ship based spring summer observations for 1996 and 1997 with satellite observations for the northern okhotsk sea polynyas five russian ctd surveys taken during 1995 to 1997 are used to examine the evolution of the polynya dense water the surveys show that consistent with other investigations the largest potential densities are 26 99 and the densest water occurs in sakhalin and shelikhov bays the surveys also suggest that the shelikhov water drains directly into the deep okhotsk while on the northern shelves gravity currents transport the dense water west to sakhalin bay for comparison determination of the polynya sizes and ice production from satellite passive microwave and meteorological observations shows that polynyas occur on the northwest shelf nws between ayan and okhotsk city on the northern shelf between okhotsk city and magadan and in shelikhov bay in contrast the observations show that sakhalin bay is a region of land fast ice with no polynyas so that the dense water observed here cannot form locally for all polynyas the satellite observations show that the nws contributes 60 to 70 of the total ice production and due to the warmer 1997 air temperatures the 1996 production is about 1 5 times the 1997 value an estimate of the ice production from the surveys shows a similar regional distribution and enhancement of the 1996 production with the satellite and ship estimates in agreement within their error bars finally analysis of the dense water outflow shows that the upper okhotsk sea mode water has a renewal time of about 4 years the lower part about 14 years

processes controlling the advance and retreat of sea ice in the sea of okhotsk using defense meteorological satellite program dmsp special sensor microwave imager ssm i sea ice data and meteorological data we investigate processes controlling the advance and retreat of sea ice in the sea of okhotsk for this investigation we apply a new algorithm to the ssm i data which is capable of calculating ice concentration and distinguishing sea ice types this algorithm is confirmed by comparison with national oceanic and atmospheric administration noaa advanced very high resolution radiometer avhrr imagery our investigations show that there exists a locality for the areas of new ice formation and the ice formation near the ice edge always occurs as a recovery after sea ice has retreated suddenly we also reveal that the speed of ice edge advance fairly coincides with that predicted by 2 of the geostrophic wind furthermore there exists a good correspondence between the times when the overall advance and retreat of ice cover begin and the decrease and increase of air temperature begin we conclude that the advance of the ice cover in the sea of okhotsk occurs primarily through ice advection by wind and that the interannual variation in the maximum sea ice extent can be interpreted by that in wind and air temperature conditions

an empirical oxygen and hydrogen isotope geothermometer for quartz tourmaline and tourmaline water abstract oxygen isotope equilibration temperatures of coexisting quartz muscovite illite chlorite and biotite from a variety of geologic environments have been used in conjunction with the 18o and d values of associated tourmaline to formulate empirical quartz tourmaline and tourmaline water isotope fractionation factors over temperatures from 200 to 600 c the fractionation factors determined using this method are as follows 1 1 1000 in quartz tourmaline 1 0 0 17 10 6 t 2 0 39 0 44 oxygen 2 2 1000 in tourmaline water 27 2 4 4 10 6 t 2 28 1 9 8 hydrogen 350 600 c the isotopic properties of tourmaline are nearly identical to those of muscovite and illite despite the significant differences in their crystal structures similarities in the oxygen and hydrogen isotope systematics of tourmalines and micas imply that the dominant controls on the isotopic properties of these minerals are the vibrational energies of the al si o and si o bonds however the bo3 groups in the tourmalines may have some effect on oxygen isotopic properties as there are minor differences between the 18o values of coexisting tourmalines and micas d values of coexisting tourmalines and micas are generally concordant to within 10 chemical compositions indicate that varying fe mg ratios in the tourmalines appear to have only a minor control on their d values there is a discontinuity in the 1000 in tourmaline water values for hydrogen at temperatures between 200 c and 300 c suggesting that the hydroxl groups in tourmaline are affected by hydrogen bonding and changes in the properties of water near its critical point as are some other hydrous minerals

slope failures on the flanks of the western canary islands abstract landslides have been a key process in the evolution of the western canary islands the younger and more volcanically active canary islands el hierro la palma and tenerife show the clearest evidence of recent landslide activity the evidence includes landslide scars on the island flanks debris deposits on the lower island slopes and volcaniclastic turbidites on the floor of the adjacent ocean basins at least 14 large landslides have occurred on the flanks of the el hierro la palma and tenerife the majority of these in the last 1 million years with the youngest on the northwest flank of el hierro as recent as 15 thousand years in age older landslides undoubtedly occurred but are difficult to quantify because the evidence is buried beneath younger volcanic rocks and sediments landslides on the canary island flanks can be categorised as debris avalanches slumps or debris flows debris avalanches are long runout catastrophic failures which typically affect only the superficial part of the island volcanic sequence up to a maximum thickness of 1 to 2 km they are the commonest type of landslide mapped in contrast slumps move short distances and are deep rooted landslides which may affect the entire thickness of the volcanic edifice debris flows are defined as landslides which primarily affect the sedimentary cover of the submarine island flanks some landslides are complex events involving more than one of the above end member processes individual debris avalanches have volumes in the range of 50 500 km3 cover several thousand km2 of seafloor and have runout distances of up to 130 km from source overall debris avalanche deposits account for about 10 of the total volcanic edifices of the small relatively young islands of el hierro and la palma some parameters such as deposit volumes and landslide ages are difficult to quantify the key characteristics of debris avalanches include a relatively narrow headwall and chute above 3000 m water depth on the island flanks broadening into a depositional lobe below 3000 m debris avalanche deposits have a typically blocky morphology with individual blocks up to a kilometre or more in diameter however considerable variation exists between different avalanche deposits at one extreme the el golfo debris avalanche on el hierro has few large blocks scattered randomly across the avalanche surface at the other icod on the north flank of tenerife has much more numerous but smaller blocks over most of its surface with a few very large blocks confined to the margins of the deposit icod also exhibits flow structures longitudinal shears and pressure ridges that are absent in el golfo the primary controls on the block structure and distribution are inferred to be related to the nature of the landslide material and to flow processes observations in experimental debris flows show that the differences between the el golfo and icod landslide deposits are probably controlled by the greater proportion of fine grained material in the icod landslide this in turn relates to the nature of the failed volcanic rocks which are almost entirely basalt on el hierro but include a much greater proportion of pyroclastic deposits on tenerife landslide occurrence appears to be primarily controlled by the locations of volcanic rift zones on the islands with landslides propagating perpendicular to the rift orientation however this does not explain the uneven distribution of landslides on some islands which seems to indicate that unstable flanks are a weakness that can be carried forward during island development this may occur because certain island flanks are steeper extend to greater water depths or are less buttressed by the surrounding topography and because volcanic production following a landslide my be concentrated in the landslide scar thus focussing subsequent landslide potential in this area landslides are primarily a result of volcanic construction to a point where the mass of volcanic products fails under its own weight although the actual triggering factors are poorly understood they may include or be influenced by dyke intrusion pore pressure changes related to intrusion seismicity or sealevel climate changes a possible relationship between caldera collapse and landsliding on tenerife is not in our interpretation supported by the available evidence

hydrodynamic modeling of tsunamis from the currituck landslide article i nfo article history accepted 24 september 2008 tsunami generation fromthe currituck landslide offshore northcarolina and propagation of waves towardthe u s coastline are modeled based on recent geotechnical analysis of slide movement a long and intermediate wave modeling package coulwave based on the non linear boussinesq equations are used to simulate the tsunami this model includes procedures to incorporate bottom friction wave breaking and overland flow during runup potential tsunamis generated from the currituck landslide are analyzed using four approaches 1 tsunami wave history is calculated from several different scenarios indicated by geotechnical stability and mobility analyses 2 a sensitivity analysis is conducted to determine the effects of both landslide failure duration during generation and bottom friction along the continental shelf during propagation 3 wave history is calculated over a regional area to determine the propagation of energy oblique to the slide axis and 4 a high resolution 1d model isdeveloped to accuratelymodel wavebreakingand the combined influence of nonlinearity and dispersion during nearshore propagation and runup the primary source parameter that affects tsunami severity for this case study is landslide volume with failure duration having a secondary influence bottom friction during propagation across the continental shelf has a strong influence on the attenuation of the tsunami during propagation the high resolution 1d model also indicates that the tsunami undergoes nonlinear fission prior to wave breaking generating independent short period waves wave breaking occurs approximately 40 50 km offshore where a tsunami bore is formed that persists during runup these analyses illustrate the complex nature of landslide tsunamis necessitating the use of detailed landslide stability mobility models and higher order hydrodynamic models to determine their hazard published by elsevier b v

magma mixing and gold mineralization in the maevatanana gold deposit madagascar abstract the maevatanana gold deposit in madagascar is hosted by archean metamorphic rocks in quartz sulfide veins that are structurally controlled by nnw sse trending shear zones fluid inclusion data show that the trapping conditions in quartz range from 0 87 to 2 58 kbar at temperatures of 269 362 c laser raman spectroscopy confirms that these inclusions consist of co 2 so 2 and h 2 o the 34 s values of the pyrites range from 1 7 to 3 6 with an average of 2 25 supporting a magmatic origin noble gases he ne ar ke xe are chemically inert thus will not be involved in chemical reactions during geological processes also due to the low concentration of he in the atmosphere and the low solubility of he in aqueous fluids the atmosphere derived he is unlikely to significantly affect he abundances and isotopic ratios of crustal fluids ensures that he production should have the typical crust 3 he 4 he ratios the 3 he 4 he ratios of fluid inclusions in pyrite from the deposit range from 0 06 to 0 12 ra while the 40 ar 36 ar ratios range from 6631 to 11441 we infer that the ore forming fluids could have been exsolved from a granitic magma the oxygen and hydrogen isotope compositions of the ore forming fluids 1 5 18 o h2o 7 8 72 d 117 indicate they were derived from a granitic magma four pyrite samples from the gold deposit yield a precise re os isochron age of 534 13 ma given that the post collisional granites in northern and central madagascar were derived by melting of sub continental lithospheric mantle and formed between 537 and 522 ma we can state that the gold metallogenesis was coeval with the crystallization age of these parental magmas these data could be accounted for the formation of the maevatanana gold deposit first the shear zones hosting the deposit formed around 2 5 ga when the madagascan micro continental blocks collided with other continental blocks triggering large scale tectono magmatic activity and forming nnw sse trending shear zones the gold mineralization at maevatanana is coeval with the crystallization age of the cambrian post collisional a type granitoid plutons in northern and central madagascar implying that this deposit is associated with extensional collapse of the east african orogen this extension in turn induced asthenospheric upwelling melting of sub continental lithospheric mantle these magmas underplated the lower crust generating voluminous granitic magmas by partial melting of the lower crust the mixing magma during tectono thermal reactivation of the east african orogen produced large volumes of volatiles that extracted gold from the granitic magma and produced au s complexes e g au hso 3 2 the shear zones which were then placed under extensional collapse of the east african orogen in the cambrian formed favorable pathways for the magmatic ore forming fluids these fluids then precipitated gold sulfides that form the maevatanana gold deposit

traveltime delay relative to the maximum energy of the wave train for dispersive tsunamis propagating across the pacific ocean the case of 2010 and 2015 chilean tsunamis

different carbon reservoirs of auriferous fluids in african archean and proterozoic gold deposits constraints from stable carbon isotopic compositions of quartz hosted co 2 rich fluid inclusions stable carbon and when present nitrogen isotope ratios of fluid inclusions in quartz from selected gold deposits in ghana and zimbabwe have been analyzed using a crushing device interfaced to an isotopic ratio mass spectrometer irms in order to constrain possible sources of the auriferous fluids the study revealed a striking difference in stable carbon isotopic compositions of co2 in quartz hosted fluid inclusions from archean and paleoproterozoic orogenic gold deposits and points to diverse sources of co2 in the studied deposits whether this finding can be generalized for other archean and proterozoic orogenic gold deposits worldwide remains open however a significant co2 contribution by mantle degassing can be ruled out for every deposit studied devolatilization of greenstone belt rocks is the most likely source for co2 in some archean au deposits in zimbabwe whereas co2 in proterozoic vein type au deposits in the west african craton is most likely derived from corg bearing metasedimentary rocks the 13cco2 values of high density co2 rich water poor inclusions hosted in quartz pebbles from the world class au bearing conglomerate deposits at tarkwa ghana differ considerably from the 13cco2 values of similar high density co2 rich inclusions in vein quartz from the giant ashanti deposit ghana and disprove the idea of derivation of the tarkwaian quartz and gold from an older equivalent to the ashanti vein type gold deposit

link between gold provinces low salinity high temperature 200 degrees c reducing fluids are poorly represented in ore forming processes yet appear to account for 90 percent of the primary gold mined to date such fluids have been implicated in the formation of many archcan greenstone witwatersrand slate belt and epithermal gold deposits these low salinity auriferous fluids occur in variable time space lithological sequence and tectonic settings and are most easily explained by metamorphic devolatilization of mafic and or graywacke successions metamorphism of chlorite calcite albite quartz assemblages e g mafic or graywacke at the greenschist amphibolite facies boundary occurs around 480 degrees or 20 degrees c for 3 5 kbars and produces large volumes of low salinity h 2 o co 2 fluid similar in composition to those recorded in many gold deposits widespread pyrite in the above assemblage typically leads to elevated levels of dissolved sulfur such conditions are ideal for gold transport as a molecular au s complex and can lead to deposits rich in gold relative to silver and base metals deposition of gold occurs in the temperature range of 250 degrees to 400 degrees c and can be facilitated by lower temperature lower sulfur activity and changes in oxygen activity lower sulfur activity is most readily achieved by fluid interaction with fe rich host rocks with the formation of pyrite or pyrrhotite whereas lower oxygen activity is readily achieved by interaction with carbonaceous metasediments low salinity fluids produced by metamorphic devolatilization provide a common theme embracing the formation of many archcan greenstone slate belt witwatersrand and potentially epithermal gold deposits it involves the common features of high geothermal gradient low salinity fluid high au ag high au base metals and broad synchroneity with metamorphism it also accounts for the considerable variability in hosting structures detailed timing relations host rocks alteration assemblages and geologic age of different deposits interestingly the similarities are explained by deeper processes the differences by processes at or near the depositional sites

origin of co2 rich fluid inclusions in synorogenic veins from the eastern mount isa fold belt nw queensland and their implications for mineralization synorogenic veins from the proterozoic eastern mount isa fold belt contain three different types of fluid inclusions co2 rich aqueous two phase and rare multiphase inclusions of co2 without a visible h2o phase are particularly common the close association of co2 rich inclusions with aqueous two phase and possibly multiphase inclusions suggests that phase separation of low to moderate salinity co2 rich hydrothermal fluids led to the selective entrapment of the co2 microthermometric results indicate that co2 rich inclusions homogenize between 15 5 and 29 9 c which corresponds to densities of 0 99 to 0 60 g cm 3 the homogenization temperatures of the associated aqueous two phase inclusions are 127 397 c with salinities of 0 5 to 18 1 wt nacl equivalent the rarely observed multiphase inclusions homogenize between 250 and 350 c and have salinities ranging from 34 6 to 41 5 wt nacl equivalent evidence used to support the presence of fluid immiscibility in this study is mainly derived from observations of coexisting h2o rich and co2 rich inclusions in groups and along the same trail in addition these two presumably unmixed fluids are also found on adjacent fractures where monophase co2 rich inclusions are closely related to h2o rich inclusions similar co2 rich inclusions are widespread in mineral deposits in this region which are simply metal enriched synorogenic veins therefore we argue that fluid immiscibility caused volatile species such as co2 and h2s to be lost from liquid thus triggering ore deposition by increasing the fluid ph and decreasing the availability of complexing ligands

numerical modeling of the june 17 2017 landslide and tsunami events in karrat fjord west greenland on june 17 2017 the western coast of greenland was the site of a tsunami which flooded several villages killing 4 people and destroying 11 houses in the village of nuugaatsiaq this tsunami was triggered by a subaerial landslide which occurred in a fjord 32 km ene of nuugaatsiaq this paper presents the numerical modeling of this landslide of sim 50 million hbox m 3 and of the tsunami propagation from its source to nuugaatsiaq the landslide is considered as a granular flow under gravity forces and the water waves generated are related to the displacement of the sea bottom the results obtained are similar in amplitude to our inferences from videos i e three water waves between 1 and 1 5 m arriving at nuugaatsiaq with a period of roughly 3 min and are also in general agreement with the amplitude 1 m resulting from deconvolution of oscillations recorded on a horizontal seismogram operating at nuugaatsiaq nuug according to the field survey performed by fritz et al egu general assembly conference abstracts vol 20 of egu general assembly conference abstracts p 18345 2018a on july 2017 a second mass next to the landslide is threatening karrat fjord a sensitivity study is realized on its volume with 2 7 14 and 38 million hbox m 3 reaching the sea the shape of the water waves is found to be independent of volume and linearity is observed between the volume and the water wave heights finally the orientation of the slide does not seem to influence either the period or the shape of the generated water waves

introduction to global tsunami science past and future volume ii twenty two papers on the study of tsunamis are included in volume ii of the pageoph topical issue global tsunami science past and future volume i of this topical issue was published as pageoph vol 173 no 12 2016 eds e l geist h m fritz a b rabinovich and y tanioka three papers in volume ii focus on details of the 2011 and 2016 tsunami generating earthquakes offshore of tohoku japan the next six papers describe important case studies and observations of recent and historical events four papers related to tsunami hazard assessment are followed by three papers on tsunami hydrodynamics and numerical modelling three papers discuss problems of tsunami warning and real time forecasting the final set of three papers importantly investigates tsunamis generated by non seismic sources volcanic explosions landslides and meteorological disturbances collectively this volume highlights contemporary trends in global tsunami research both fundamental and applied toward hazard assessment and mitigation

fundamental mechanisms for tsunami generation by submarine mass flows in idealised geometries tsunami generation from submarine gravity mass flows is investigated using linear two dimensional analytical models a simplified slide geometry and a prescribed sub critical slide velocity slide characteristics as maximum slide velocity initial acceleration slide length and thickness are all found to determine the characteristics of the tsunami effects of dispersion usually turn out to be of minor practical importance tsunamis due to retrogressive slides are generally smaller than for a similar fixed shaped slide with the same characteristics due to an increased duration of slide mass mobilisation however above the rear of the slide the surface elevation can also be increased for small time lags

fluid inclusions in charnockites from the bjerkreim sokndal massif rogaland southwestern norway fluid origin and in situ evolution fluid inclusions and mineral associations were studied in late stage charnockitic granites from the bjerkreim sokndal lopolith rogaland anorthosite province because the magmatic and tectonic evolutions of this complex appear to be relatively simple these rocks are a suitable case for investigation of the origin and evolution of granulitic fluids fluid inclusions primarily contained in quartz can be divided into four types carbonic type i n2 bearing type ii co2 h2o type iii and aqueous inclusions type iv for each type the role of leakage and fluid mixing are discussed from microthermometric and raman spectrometric data the most striking features of co2 rich inclusions the predominant fluid is the presence of graphite in numerous trail bound inclusions ib and its absence in a few isolated very dense d 1 16 pure co2 inclusions ia and in the late carbonic inclusions ic fluid chronology and mineral assemblages suggest that carbonic ia inclusions represent the first fluid pure co2 trapped at or close to magmatic conditions t 780 830 c fo2 10 15 atm and p 7 4 1 kb outside the graphite stability field in contrast type ib inclusions enclosed graphite particles from a channelized fluid during retrograde rock evolution p 3 4 kb and t 600 c decreases in t fo2 could explain a progressive evolution from a co2 rich fluid to an h2o rich fluid in a closed c o h system however graphite destabilization observed in type ic inclusions implies some late introduction of external water during the last stage of retrogression the main results of this study are the following 1 a carbonic fluid was present in an early stage of rock evolution probably in the charnockitic magma and 2 this granulite occurrence offers good evidence of crossing the graphite stability field during post magmatic evolution

extreme runup from the 17 july 2006 java tsunami 1 the 17 july 2006 magnitude mw 7 8 earthquake off the south coast of western java indonesia generated a tsunami that effected over 300 km of coastline and killed more than 600 people with locally focused runup heights exceeding 20 m this slow earthquake was hardly felt on java and wind waves breaking masked any preceding withdrawal of the water from the shoreline making this tsunami difficult to detect before impact an international tsunami survey team was deployed within one week and the investigation covered more than 600 km of coastline measured tsunami heights and run up distributions were uniform at 5 to 7 m along 200 km of coast however there was a pronounced peak on the south coast of nusa kambangan where the tsunami impact carved a sharp trimline in a forest at elevations up to 21 m and 1 km inland local flow depth exceeded 8 m along the elevated coastal plain between the beach and the hill slope we infer that the focused tsunami and runup heights on the island suggest a possible local submarine slump or mass movement

fluid immiscibility in natural processes use and misuse of fluid inclusion data ii interpretation of fluid inclusion data in terms of immiscibility abstract phase equilibrium analysis of the relevant systems together with the application of the principles of chemical equilibrium put severe constraints on the interpretation of fluid inclusion data in terms of immiscibility in part i following from that point the major limits on the accuracy and even the validity of fluid inclusion quantitative data and their interpretation in terms of fluid composition and density are briefly discussed the practical implications of the general constraints temperature pressure topology of the fluid systems are envisaged emphasis is laid on some important consequences such as the use of isochore intercepts and the possible resulting interpretation of fluid mixing rather than unmixing the case of highly saline inclusions the identification and interpretation of heterogeneous trapping the composition and density constraints on coexisting fluids are presented and illustrated by natural examples taking into account all the measurable parameters in fluid inclusions volume temperature and nature of phase transitions more or less complete individual spectroscopic analyses all the available experimental data and all the theoretical constraints may be long and difficult however it is most generally very informative and productive although part of these data is often sufficient to deny unmixing nevertheless a final example on metamorphic fluids demonstrates how such an approach can prove and also characterize a fluid unmixing during a geologic process

tectono metamorphic evolution of the karakoram terrane constrained from p t t fluid history of garnet bearing amphibolites from trans himalaya ladakh india abstract this study presents new data sets on the petrological fluid inclusion and u pb zircon geochronological aspects of the garnet bearing amphibolites from the eastern karakorum pangong tso ladakh to delineate the p t t fluid evolution and its tectonic implications the calculated phase equilibria in the model system nckfmashto reveal that the peak metamorphism occurred at 8 5 9 5 kbar 630 655 c and retrograde metamorphism crossed a stage at 5 5 5 7 kbar 620 630 c monophase primary and secondary carbonic and carbonic aqueous fluid inclusions occur in garnet and quartz trapping of the primary inclusion occurred at pressures lower than the estimated peak p t conditions 5 8 6 1 kbar 629 638 c indicative of partially re equilibrated fluid inclusions during exhumation the primary inclusions were original as carbonic aqueous fluid derived from prograde decarbonation of the amphibolite s protolith or adjacent carbonate rich rocks and h2o leached out during deformation leaving a pure co2 fluid u pb dating of zircons yielded two age groups i at 128 to 131 ma interpreted as the age of detrital zircons of sedimentary derivation and constrain the maximum depositional age of the sedimentary protolith at 131 ma and ii at 114 0 38 ma is interpreted as the age of peak metamorphism remarkably similar to the metamorphic age of the surrounding metapelites this metamorphic stage corresponds to the well known cretaceous phase of crustal thickening and heating along the active continental margin of south asia

relationship between co2 dominated fluids hydrothermal alterations and gold mineralization in the red lake greenstone belt canada abstract the red lake greenstone belt is one of the foremost au mining camps in canada and hosts the world class campbell red lake au deposit belt scale hydrothermal alteration is characterized by proximal ferroan dolomite zones associated with au mineralization surrounded by distal calcite zones both being accompanied by potassic alterations sericite muscovite and biotite at the campbell red lake and cochenour deposits au mineralization in particular high grade ore is associated with silica and sulfides especially arsenopyrite that replace carbonate quartz veins and the host rocks the prevalence of carbonic fluid inclusions and rare occurrence of aqueous bearing inclusions in carbonate quartz au veins in the campbell red lake deposit and the consistency of homogenization temperatures of carbonic inclusions within individual fluid inclusion assemblages fia have been interpreted to indicate that h2o poor co2 dominated fluids were responsible for the carbonate veining and au mineralization further studies of fluid inclusions in carbonate quartz veins within and outside the deformation zone hosting the campbell red lake deposit the red lake mine trend including the cochenour au deposit the redcon au prospect and outcrops in the distal calcite zone also reveal the dominance of carbonic fluid inclusions in vein minerals these studies indicate that co2 dominated fluids were flowing through fractures during carbonate vein formation and au mineralization both within and outside major structures the carbonic fluid may have been initially undersaturated with water or it may have resulted from phase separation of an h2o co2 nacl fluid in the latter case phase separation modeling indicates that the initial fluid likely had x co 2 values larger than 0 8 calculations based on hydrothermal mineral assemblages indicate x co 2 values in the host rocks from 0 025 to 0 85 reflecting a change from co2 dominated fluids in the fractures veins to h2o dominated fluids in the host rocks away from the fractures the co2 dominated fluids were likely advected from granulite facies in the deeper crust whereas the h2o dominated fluids were derived from the ambient host rocks of amphibole to greenschist facies calculations based on co2 requirements and source constraints indicate that the mineralizing fluids were likely two orders of magnitude more enriched in au than the commonly assumed values of a few g l which may explain why the campbell red lake deposit has a very high grade of au average 21 g t for the whole deposit and 81 g t for the goldcorp high grade zone fluid inclusion data suggest that the carbonate veining and au mineralization likely took place at depths from 7 to 14 km the development of crustiform colloform structures in the carbonate quartz veins which was previously interpreted to indicate relatively shallow environments may alternatively have been related to extremely high fluid pressures and the co2 dominated nature of the fluids which could have enhanced the brittle properties of the rocks due to their high wetting angles

full paleostress tensor reconstruction using quartz veins of panasqueira mine central portugal part i paleopressure determination abstract paleostress tensor restoration methods are traditionally limited to reconstructing geometrical parameters and are unable to resolve stress magnitudes based on previous studies we further developed a methodology to restore full paleostress tensors we concentrated on inversion of mode i fractures and acquired data in panasqueira mine portugal where optimal exposures of mineralized quartz veins can be found to carry out full paleostress restoration we needed to determine 1 pore paleo pressure and 2 vein attitudes the present contribution focuses specifically on the determination of pore pressure to these aims we conducted an extensive fluid inclusion study to derive fluid isochores from the quartz of the studied veins to constrain p t conditions we combined these isochores with crystallisation temperatures derived from geochemical analyses of coeval arsenopyrite we also applied the sphalerite geobarometer and considered two other independent pressure indicators our results point to pore pressures of 300 mpa and formation depths of 10 km such formation depths are in good agreement with the regional geological evolution the obtained pore pressure will be merged with vein inversion results in order to achieve full paleostress tensor restoration in a forthcoming companion paper

bicarbonate rich fluid inclusions and hydrogen diffusion in quartz from the libcice orogenic gold deposit bohemian massif abstract unusual paleofluid composition is reported for the libcice orogenic type gold deposit located in the central bohemian plutonic complex cbpc czech republic unexpected bicarbonate rich fluids and their complex chemistry variations characterize primary fluid inclusions from the main gold bearing quartz vein a detailed microthermometry laser raman micro spectroscopy lrms and sem cathodoluminescence study was used to understand the complex chemistry and p t x history the results indicate the presence of h 2 o and h 2 o co 2 ch 4 n 2 h 2 s fluids the latter displaying variations of the co 2 ch 4 ratio in the gaseous phase from 6 8 to 0 06 variation of the ch 4 content across single grains and between different levels of the mine was recorded the presence of nahcolite h 2 up to 6 mol and ethane 0 0 2 mol in the fluids were also discovered by lrms potential models for the formation of different types of fluids present in the deposit are discussed including the genesis of hco 3 rich fluids as well as h 2 and c 2 h 6 presence in the primary fluid inclusions the potential influence of organic matter bearing sediments as well as the impact of the intrusion of cbpc re equilibration and or re speciation of fluid inclusions during the post entrapment history is considered to have the main impact on the complex paleofluid chemistry based on the thermodynamic modeling h 2 diffusion into the fluid inclusions was shown to be the main reason for the ch 4 variation on the scale of a single grain as well as across the whole vein although the exact processes of production formation of hco 3 and h 2 at the libcice deposit remain open to discussion reactions in the c o h system are considered to be a possible formation mechanism this work also contributes to our understanding of the importance of post entrapment modifications and reactions in the c o h system on interpretation deciphering the processes in orogenic type deposits

the 1979 submarine landslide generated tsunami in mururoa french polynesia this paper aims at best describing the submarine landslide which induced partial submersion of the atolls of mururoa and fangataufa in 1979 more precisely waves propagated along the south coast of mururoa atoll and penetrated into its lagoon some minutes after the landslide triggering t 0 s whereas a train of eight water waves reached the runway located on the north east coast of fangataufa 40 km south of mururoa between t 7 min 30 s and t 20 min a numerical model based on shallow water equations is used to simulate the landslide as well as the associated tsunami saint venant equations are used to propagate the tsunami in coastal areas whereas the offshore propagation is simulated by solving weakly nonlinear boussinesq equations low and high resolution nested grids are used to simulate the tsunami propagation in deep sea and in shallow waters respectively several scenarios have been tested to reproduce the observed water and run up heights in the near and far fields the best scenarios correspond to a landslide with a volume in the range 75 90 mm3 for a basal friction angle of 35 and with a basal friction angle in the range 30 40 for a volume of 80 mm3 these results have been completed by a parametric study on the slide parameters

the origin and significance of non aqueous co2 fluid inclusions in the auriferous veins of bin yauri northwestern nigeria non aqueous co2 and co2 rich fluid inclusions are found in the vein quartz hosting mesothermal gold sulphide mineralization at bin yauri northwestern nigeria although mineralizing fluids responsible for gold mineralization are thought to be co2 rich the occurrence of predominantly pure to nearly pure co2 inclusions is nevertheless unusual for a hydrothermal fluid system many studies of similar co2 rich fluid inclusions mainly in metamorphic rocks proposed preferential loss leakage of h2o from h2o co2 inclusions after entrapment in this study however it is proposed that phase separation fluid immiscibility of low salinity co2 rich hydrothermal fluids during deposition of the gold mineralization led to the loss of the h2o phase and selective entrapment of the co2 the loss of h2o to the wallrocks resulted in increasing oxidizing effects there is evidence to suggest that the original co2 rich fluid was intrinsically oxidized or perhaps in equilibrium with oxidizing conditions in the source rocks the source of the implicated fluid is thought to be subducted metasediments subjected to dehydration and devolatilization reactions along a transcurrent anka fault shear system which has been described as a pan african 450 750 ma crustal suture

enrichment of co2 in fluid inclusions in quartz by removal of h2o during crystal plastic deformation abstract ductile strain induced leakage of h 2 o from mixed co 2 h 2 o fluid inclusions in quartz is proposed as a mechanism for producing occurrences of pure co 2 fluid inclusions in metamorphic rocks the h 2 o needed for hydrolytic weakening of quartz under stress may be provided by the h 2 o in fluid inclusions with dislocation creep as dislocations nucleate on the walls of fluid inclusions or intersect them h 2 o can be transported with the dislocations from the inclusion to the grain boundaries the process should continue so long as there is stress on the host quartz and the inclusion contains h 2 o the h 2 o taken to the grain boundaries would due to its wetting properties be wicked out along the grain boundaries if the h 2 o is totally removed from an inclusion by a flux of dislocations through the quartz during the crystal plastic flow then a residual inclusion bearing components other than water should remain a mixed co 2 h 2 o inclusion would as a consequence of the process become a pure co 2 fluid inclusion during dynamic recrystallization the co 2 would collect at grain boundary triple junctions and following grain boundary migration would become incorporated into the recrystallized quartz as fluid inclusions this mechanism of generating pure co 2 inclusions could result in co 2 fluid inclusions having densities appropriate for the pressure temperature conditions during deformation using estimates of temperature of deformation the total confining pressure during deformation could be determined from the density of the co 2 fluid in these inclusions

refined numerical modeling of the 1979 tsunami in nice french riviera comparison with coastal data 1 the 16 october 1979 landslide at nice airport france produced tsunami waves observed in several harbors and the city of antibes was significantly flooded a new simulation of this event is presented in this paper to assess the sensitivity of the tsunami to the properties of the slide and to evaluate how local bathymetry and harbor resonance influence the effects of the tsunami at the coast a study of slide viscosity and water incorporation is performed using a detailed numerical model with a single initial volume of about 107 m3 the propagation of the tsunami is then simulated with a multigrid finite difference code using high resolution bathymetry in the harbors to a greater level of detail than previous studies we show that while the slide parameters are of great importance to properly model the later stages of the slide the initial volume and early dynamics of the slide are the relevant factors for determining the characteristics of the tsunami numerical results are compared with tide recordings in nice and villefranche as well as a mapping of the flood computed maximum elevation maps are compared with witness reports highlighting a focusing of the waves on antibes which explains its vulnerability this kind of focusing pattern should be considered when assessing the tsunami hazard for coastal regions calculated resonant periods in nice villefranche port vauban and la salis are matched with components present in both observed and computed waveforms most of the observed waves in nice and villefranche can be attributed to resonance

carbonic fluid inclusions in south indian granulites evidence for entrapment during charnockite formation field evidence and fluid inclusion studies on south indian incipient charnockites suggest that charnockite formation occurred during a decompressional brittle regime following the peak of metamorphism and regional deformation the most abundant type of inclusions in quartz and garnet grains in these charnockites contain high density carbonic fluids although lower density fluids occur in younger arrays of inclusions discrete fluid inclusion generations optically are observed to decrepitate over well defined temperature intervals and quantitative measurements of co2 abundance released from these inclusions by stepped thermal decrepitation show up to a four fold increase by volume in the incipient charnockites relative to the adjacent gneisses from which they are derived studies based on optical thermometry visual decrepitation and stepped heating inclusion release together indicate that entrapment of carbonic fluids coincided with charnockite formation we confirm that an influx of carbon dioxide rich fluids is associated with the amphibolite granulite transition as recorded by the incipient charnockites the remnants of which are commonly preserved as the earliest generation of high density fluid inclusions

the origin of fluids and nature of fluid rock interaction in mid crustal auriferous mylonites of the renco mine southern zimbabwe geothermometric constraints on auriferous shear zones of the renco mine in the northern marginal zone of the late archaean granulite facies limpopo belt in southern zimbabwe indicate that deformation and associated mineralization occurred at temperatures of at least 600 c up to more likely 700 c mid to upper amphibolite facies conditions during mineralization correspond to the regional scale retrogression of granulite facies wall rocks during the late archaean thrusting of high grade metamorphic rocks of the northern marginal zone onto low to medium grade granite greenstone terrains of the zimbabwe craton mineral assemblages indicate that the ore fluid was moderately oxidized with log fo2 values between 10 17 and 10 18 bars with high h2s activities of 0 25 0 75 elements enriched in the shear zones include au s fe cu mo bi te ni co and h2o au and cu being the most enriched geochemically au correlates with cu but not with s which together with the fact that gold is only rarely intergrown or in direct contact with sulfides possibly indicates a transport of gold as a chloride complex the siting of gold along fractures or within implosion breccias suggests that gold was precipitated due to fluid immiscibility induced by catastrophic fluid pressure drops during seismic slip events fluid inclusions are predominantly co2 ch4 n2 rich but petrographic work indicates that fluid inclusions have undergone extensive post entrapment modifications due to the pervasive recrystallization of mineral textures in the high temperature shear zones the mineralized shear zones are enriched in 18o compared to wall rock enderbites which is interpreted to represent an influx of externally derived fluids of probably metamorphic origin based on temporal and spatial relationships between mineralization late archaean overthrusting of the northern marginal zone onto the zimbabwe craton and coeval amphibolite facies hydration of granulites we suggest that the renco mineralization formed in a mid crustal environment from metamorphic fluids that were generated from dehydration of subcreted greenstone terrains of the zimbabwe craton

physical modeling of tsunamis generated by three dimensional deformable granular landslides 1 tsunamis generated by deformable granular landslides are physically modeled in a three dimensional tsunami wave basin based on the generalized froude similarity the dynamic landslide impact characteristics were controlled by means of a novel pneumatic landslide generator the wave amplitudes periods and wavelengths are related to the landslide parameters at impact with the landslide froude number being a dominant parameter between 1 and 15 of the landslide kinetic energy at impact is converted into the wave train energy the wave amplitudes decay in radial and angular directions from the landslide axis the first wave crest mostly travels with speeds close to the theoretical approximation of the solitary wave speed the measured tsunami wave profiles were either of the nonlinear oscillatory or nonlinear transition type depending primarily on the landslide froude number and relative slide thickness at impact the generated waves range from shallow to deep water depth regimes with the majority being in the intermediate water depth regime wave characteristics are compared with other two and three dimensional landslide tsunami studies and the results are discussed

raman spectroscopic densimeter for pure co2 and co2 h2o nacl fluid systems over a wide p t range up to 360 c and 50 mpa abstract density of fluid inclusions is one of the most important parameters to reconstruct the p t conditions of entrapment of geo fluids co existing with microthermometry methods raman spectroscopy also became a useful tool to determine the density of co2 bearing inclusions via fermi diad splitting in this study a new co2 densimeter which takes into account the effects of temperature pressure and h2o nacl on fermi diad splitting was built from experiments using a high pressure optical cell raman spectra of co2 were collected in the range 20 to 360 c and 0 51 to 50 mpa i e a density range from 0 0057 to 1 1600 g cm 3 our results show that temperature and pressure have significant impact on density relationship with lower by up to about 0 5 cm 1 with increasing pressure and temperature at a given density on the contrary dissolved h2o nacl had no effect on the density relationship so the function defined for pure co2 system can also be applied to calculate the density of co2 h2o nacl system up to 360 c 50 mpa and 20 35 wt nacl the new densimeters presented in this study provide a useful tool to determine the pressure of co2 rich fluid inclusions all along the isochoric path for any water concentration

does gold in orogenic deposits come from pyrite in deeply buried carbon rich sediments insight from volatiles in fluid inclusions the origin of volatiles in fluid inclusions was reviewed for testing the involvement at depth of carbonaceous pyritic sedimentary rocks as the source for orogenic gold mineralization fluid inclusions from selected deposits were analyzed by solid probe mass spectrometry fluids are mostly aqueous carbonic with variable amounts of n 2 ch 4 c 2 h 6 ar h 2 s h 2 and he for fluids with ch 4 and c 2 h 6 their ratios c 1 c 2 range from 2 6 to 25 5 indicating that c 2 h 6 is sourced from thermally degraded organic matter proportions of co 2 ch 4 c 2 h 6 and h 2 are highly variable and can be explained by hydrothermal reactions where c 2 h 6 is degraded to co 2 by water consumption such reactions may account for the problematic co 2 rich h 2 o poor fluids associated with some of the richest gold districts conditions needed for c 2 h 6 degradation are also fundamental for forming gold deposits such as hs enriched fluids for carrying gold and local weakly oxidizing conditions for promoting gold precipitation the c 2 h 6 content is recorded in fluids from mesoarchean to cretaceous gold deposits providing support for a general model where fluids and gold were sourced from deeply buried carbon rich and pyrite gold bearing sedimentary rocks

the coupling of a submarine slide and the surface waves which it generates underwater landslides are a common source of small scale tsunamis in coastal areas they have been the object of only a few theoretical and experimental studies a numerical model is developed to study the coupling of a submarine landslide and the surface waves which it generates a formulation of the dynamics of the problem is presented where the landslide is treated as the laminar flow of an incompressible viscous fluid and the water motion is assumed irrotational long wave approximation is adopted for both water waves and the mudslide the resulting differential equations are solved by a finite difference method we present the numerical results which contrast the behavior of the mud flow under a fixed surface in the presence of one way coupling bottom deformations affect the free surface and with full coupling surface pressure gradients react on the mud flow it is found that three main waves are generated by a landslide starting from rest on a gentle uniform slope the first wave is a crest which propagates away from the mudslide site into deeper water this crest is followed by a trough in the form of a forced wave which propagates with the speed of the mudslide front the third wave is a relatively small trough which propagates shoreward two major parameters dominate the interaction between the slide and the waves it produces the density of sliding material and the depth of water at the mudslide site the two way interactions are significant for the cases of a smaller mud density and shallower waters for the cases of larger mud density and shallower waters the two way interactions are small but the waves generated are very large for larger initiation depth of the mudslide the interactions are weak and the waves generated are small we also examined the possibility of a resonance between the slide and the waves our numerical results indicate that a resonance is not expected in many practical cases

fluid evolution of indus basin ladakh north west himalaya india constraint from fluid inclusion and oxygen isotope thermometry fluid inclusions and oxygen isotope thermometry were carried out on quartz calcite veins of the indus basin in indus suture zone isz of northwest ladakh himalaya to constrain fluid evolution history of the basin three types of veins are identified as fault fill network and sigmoidal in the study area the fault fill veins microstructures of calcite and quartz suggest the deformation temperature of veins between 250 and 400 c and oxygen isotope thermometry provide the range between 192 and 359 c the network type veins microstructures of calcite revel deformation temperature in the range of 170 250 c and oxygen isotope thermometry indicate vein temperature range between 144 and 276 c stable isotopic values of sigmoidal and network type veins suggest the magmatic source of fluid the fault fill veins display magmatic to the marine fluid signature microstructures and isotope data set advocate the formation of veins from the wall rocks by leaching processes fluid inclusion microthermometric dataset indicates that veins were formed at a maximum depth of 20 km at 700 c the co2 fluids were trapped below 6 2 kbar at 700 c ch4 fluid was trapped at a shallower depth between 4 2 kbar 650 c and 2 3 kbar 381 c the primary aqueous fluids were trapped below 3 0 kbar up to 2 3 kbar at 594 to 382 c and secondary aqueous fluids were trapped between 2 9 and 1 5 kbar at 359 to 197 c the p t path for the entrapment defines an initial isothermal decompression itd itd is also supported by decrepitated and stretched inclusions texture as well as c shaped or hook like fluid inclusions morphology which collectively points towards fast basin uplift

nature of ore forming fluids wallrock alteration and p t conditions of gold mineralization at hira buddini hutti maski greenstone belt dharwar craton india abstract gold mineralization at hira buddini deposit in hutti maski greenstone belt of dharwar craton india is associated with quartz veins and hydrothermal alteration formed during a brittle ductile deformation episode the vein minerals quartz and plagioclase exhibit microstructures of dynamic recrystallization intracrystalline deformation estimated temperature and pressure condition during mineralization is around 500 c and 2 05 4 36 kbar respectively carbonic inclusions are the most abundant type of fluid inclusions found in quartz grains of mineralized veins such abundance of carbonic inclusions must be due to preferential loss of water from original fluid inclusions during intracrystalline deformation of quartz rock fluid interaction led to enrichment of sio2 in the form of quartz veins k pb s and loi in the auriferous lode it is inferred that the hydrothermal fluids involved in gold mineralization were of both metamorphic and magmatic origin deposition of gold has been attributed to phase separation as well as wall rock sulfidation

co 2 rich fluid inclusions with chalcopyrite daughter mineral from the fenghuangshan cu fe au deposit china implications for metal transport in vapor co2 rich fluid inclusions containing opaque mineral crystals were found in the fenghuangshan skarn porphyry cu fe au deposit in tongling anhui china these inclusions show variable co2 contents and are accompanied by aqueous inclusions both occurring as secondary inclusions in quartz and being locally associated with chalcopyrite mineralization laser raman microspectroscopic analyses confirm the predominance of co2 in the vapor and the presence of h2s as high as 8 mol and identify the opaque mineral with yellow reflectance color in the inclusions as chalcopyrite more than half of the co2 bearing inclusions contains chalcopyrite whereas few of the associated aqueous inclusions do so the chalcopyrite occupying less than 1 volume of the inclusions is interpreted to be a daughter mineral and calculated cu concentrations in the inclusions range from 0 1 to 3 4 wt copper is inferred to have been transported in co2 dominated fluids as hs complexes the occurrence of chalcopyrite daughter crystals in co2 rich fluid inclusions indicates that co2 rich vapor has the capacity of transporting large amounts of cu and possibly au this finding has significant implications for metal transport and mineralization in hydrothermal systems enriched in co2 such as orogenic type and granitic intrusion related gold deposits

terrestrial organic carbon contributions to sediments on the washington margin elemental and stable carbon isotopic compositions and biomarker concentrations were determined in sediments from the columbia river basin and the washington margin in order to evaluate geochemical approaches for quantifying terrestrial organic matter in marine sediments the biomarkers include an homologous series of long chain n alkanes derived from the surface waxes of higher plants phenolic and hydroxyalkanoic compounds produced by cuo oxidation of two major vascular plant biopolymers lignin and cutin all marine sediments including samples collected from the most remote sites in cascadia basin showed organic geochemical evidence for the presence of terrestrial organic carbon using endmember values for the various biomarkers determined empirically by two independent means we estimate that the terrestrial contribution to the washington margin is 60 for shelf sediments 30 for slope sediments and decreases further to 15 in basin sediments results from the same geochemical measurements made with depth in gravity core 6705 7 from cascadia seachannel suggest that our approach to assess terrestrial organic carbon contributions to contemporary deposits on the washington margin can be applied to the study of sediments depositing in this region since the last glacial period

fluid inclusion study of the ore quartz veins at haftcheshmeh porphyry copper mo deposit ahar arasbaran magmatic belt nw iran abstract the haftcheshmeh porphyry copper deposit in alborz arasbaran magmatic belt aamb of northwestern iran is hosted by i type granitoids of calcalkaline series of eocene to miocene age the mineralization consists of chalcopyrite molybdenite rare amounts of covellite pyrite and magnetite that are commonly found in silicified veins of the potassic sericitic alteration zones in the host quartzdiorite quartzmonzonite and granodiorite porphyries the obtained fluid inclusion data t mco 2 57 5 to 60 5 c in ore quartz veins shows enrichment in co 2 the coexistence of cu sulfide daughter crystals together with halite crystals and the co 2 bearing fluid inclusions suggest the presence of two immiscible fluids a high salinity co 2 rich magmatic fluid with high metal contents 31 1 and 48 4 wt nacl equivalent t h 169 to 500 c and a low salinity fluid 0 88 and 11 1 wt nacl equivalent t h 242 to 418 c whereas the presence of liquid and gaseous co 2 implies fluid immiscibility measured first melting temperatures of 21 to 40 c in fluid inclusions of the ore quartz veins at haftcheshmeh deposit are below the eutectic point of nacl h 2 o indicating the presence of bivalent cations including the copper salt cucl 2 4h 2 o in the ore solution the salinity of the magmatic fluids in the a type quartz veins 31 8 to 43 1 wt nacl equivalent is close to the salinities in the d type quartz veins 31 1 to 48 4 wt nacl equivalent and the homogenization temperatures of lv inclusions in the a type quartz veins 242 to 327 c are only slightly lower than in the d type quartz veins 261 to 387 c these data together with the very close homogenization temperatures of vl inclusions in the a type 302 to 418 c and the d type quartz veins 300 to 395 c suggest similar ore fluid sources for both quartz vein types the 18 o values of the ore quartz veins showing a typical magmatic fluid and suggests that the early fluid inclusions were of magmatic origin it is envisaged that co 2 degassing in the primary magma at haftcheshmeh could have led to separation of the vapor phase and destabilization of the metal transporting complexes and the ore formation

a parametric study of tsunamis generated by submarine slides in the ormen lange storegga area off western norway tsunami generation by submarine slides have been a major concern in the risk assessment for the ormen lange gas field off western norway tsunamis are analysed with a numerical model supplemented by an analytical one both models show how slide extensions and slide dynamics influence the tsunamigenic potential for a large region several combinations of slide parameters were tested and the product of initial acceleration and the volume of the slide gave the best correlation with the maximum surface elevation for the near coastal domain

the landslide generated tsunami of november 3 1994 in skagway harbor alaska a case study we examine the origin and behavior of the catastrophic tsunami that impacted skagway harbor at the head of taiya inlet alaska on november 3 1994 geomorphologic and tide gauge data combined with numerical simulation of the event reveal that the tsunami was generated by an underwater landslide formed during the collapse of a cruise ship dock undergoing construction use of a fine grid model for skagway harbor and a coarse grid model for taiya inlet enables us to explain many of the eyewitness accounts and to reproduce the dominant oscillations in the tide gauge record including the persistent 1 h 3 min oscillation in skagway harbor the occurrence of the landslide is linked to critical overloading of the slope materials at a time of extreme low tide

on the characteristics of landslide tsunamis this review presents modelling techniques and processes that govern landslide tsunami generation with emphasis on tsunamis induced by fully submerged landslides the analysis focuses on a set of representative examples in simplified geometries demonstrating the main kinematic landslide parameters influencing initial tsunami amplitudes and wavelengths scaling relations from laboratory experiments for subaerial landslide tsunamis are also briefly reviewed it is found that the landslide acceleration determines the initial tsunami elevation for translational landslides while the landslide velocity is more important for impulsive events such as rapid slumps and subaerial landslides retrogressive effects stretch the tsunami and in certain cases produce enlarged amplitudes due to positive interference in an example involving a deformable landslide it is found that the landslide deformation has only a weak influence on tsunamigenesis however more research is needed to determine how landslide flow processes that involve strong deformation and long run out determine tsunami generation

emplacement depth and carbon dioxide rich fluid inclusions in intrusion related gold deposits phanerozoic intrusion related gold deposits have many consistent characteristics such as a spatial temporal and geochemical association with moderately reduced predominantly ilmenite series i type intrusions the deposits exhibit a range of characteristics that vary over a wide range of emplacement depths 7 km deposits in shallow crustal settings 5 km have characteristics of mesothermal environments and are hosted by plutons containing sheeted veins greissen and disseminated gold fluid characteristics also vary with depth deposits in shallow environments contain high temperature 350 c immiscible brine 30 wt nacl equiv and low salinity 5 wt nacl equiv vapor that commonly contains carbon dioxide deposits in deeper environments contain abundant low salinity carbon dioxide rich aqueous fluids 10 wt nacl equiv that in some deposits are postdated by moderate to high salinity brines 10 40 wt nacl equiv these contrasting fluid types are interpreted to be magmatic in origin and are the result of the complex interplay between exsolution of different volatiles carbon dioxide water and chlorine from felsic magmas emplaced at different crustal levels experimental studies have shown that carbon dioxide will exsolve from felsic magmas at much higher pressures than water and chlorine due to its lower solubility in the melt thus deposits formed from felsic magmas in deeper environments will contain abundant carbon dioxide rich fluids subsequent fluids released from the magma are likely to be water rich and more saline felsic magmas in shallow environments will contain lower concentrations of carbon dioxide that will partition into the vapor phase during phase separation between brine and vapor

lignin phenols and bit index distributions in the amur river and the sea of okhotsk implications for the source and transport of particulate terrestrial organic matter to the ocean delta and coastal regions play a key role in the global carbon cycle as the main repository of inputs of terrestrial organic matter delivered by rivers to marine sediments the amur river system is one of the largest in asia and supplies organic matter to the sea of okhotsk and the north pacific ocean we measured lignin phenols a proxy for terrestrial plant derived organic matter and the branched and isoprenoidal tetraether bit index a proxy for riverborne soil organic matter in soils and river bed sediments from the amur river basin and surface sediments from the sea of okhotsk to study the source transport and deposition of fluvial particulate organic matter to the ocean concentrations of lignin phenols are relatively high in sediments from the shallow continental shelf compared to that of the deep offshore basin for the first time we report a spatial distribution of the bit index which shows a similar pattern to that of lignin phenol concentrations with relatively high values in the coastal sites the highest values of both lignin concentrations and bit values are observed in a site proximal to mouth of amur river these results indicate that terrestrial organic matter deposited in the sea of okhotsk mostly originates from soil organic matter supplied from amur river spatial distributions of lignin phenols toc lp toc and the bit index in the sea of okhotsk and comparison with s v a contribution index of angiosperm vs gymnosperms and c v ratios indicative of the relative contribution of non woody tissue vs woody tissue between the amur river basin and okhotsk sea samples suggest that amur river fluvial organic matter is supplied and deposited to the northwestern continental shelf furthermore s v values from our amur river and okhotsk sea continental shelf sediment samples are consistent with the reported s v ratio 0 32 of particulate organic matter in the north pacific intermediate water npiw layer 750 m depth hence our study supports previous studies from the nw pacific ocean which suggest inputs of terrestrial organic matter from the amur river via the sea of okhotsk as a major source of particulate organic matter to the north pacific ocean

disentangling marine soil and plant organic carbon contributions to continental margin sediments a multi proxy approach in a 20 000 year sediment record from the congo deep sea fan abstract a 20 kyr long sediment sequence from the congo deep sea fan core geob 6518 1 one of the world s largest deep sea river fans has been analysed for bulk and molecular proxies in order to reconstruct the marine soil and plant organic carbon oc contributions to these sediments since the last glacial maximum the bulk proxies applied c n ratio and 13 c org ranged from 10 to 12 5 and from 24 5 to 21 vpdb respectively as molecular proxies concentrations of marine derived alkenones and terrestrial derived odd numbered n alkanes were used which varied between 0 2 and 4 g g dry weight sediment in addition the branched vs isoprenoid tetraether bit index a proxy for soil organic matter input was used which varied from 0 3 to 0 5 in this core application of binary mixing models based on the different individual proxies showed estimates for terrestrial oc input varying by up to 50 due to the heterogeneous nature of the oc application of a three end member mixing model using the 13 c org content the c n ratio and the bit index enabled the distinction of soil and plant organic matter as separate contributors to the sedimentary oc pool the results show that marine oc accounts for 20 to 40 of the total oc present in the deep sea fan sediments over the last 20 kyr and that soil oc accounts for about half 45 on average of the oc present this suggests that soil oc represents the majority of the terrestrial oc delivered to the fan sediments accumulation rates of the plant and soil oc fractions over the last 20 kyr varied by a factor of up to 5 and are strongly related to sediment accumulation rates they showed an increase starting at ca 17 kyr bp a decline during the younger dryas peak values during the early holocene and lower values in the late holocene this pattern matches with reconstructions of past central african humidity and congo river discharge from the same core and revealed that central african precipitation patterns exert a dominant control on terrestrial oc deposition in the congo deep sea fan marine oc accumulation rates are only weakly related to sediment accumulation rates and vary only little over time compared to the terrigenous fractions these variations are likely a result of enhanced preservation during times of higher sedimentation rates and of relative small fluctuations in primary production due to wind driven upwelling

the 2006 july 17 java indonesia tsunami from satellite imagery and numerical modelling a single or complex source summary the mw 7 8 2006 july 17 earthquake off the southern coast of java indonesia has been responsible for a very large tsunami causing more than 700 casualties the tsunami has been observed on at least 200 km of coastline in the region of pangandaran west java with run up heights from 5 to more than 20 m such a large tsunami with respect to the source magnitude has been attributed to the slow character of the seismic rupture defining the event as a so called tsunami earthquake but it has also been suggested that the largest run up heights are actually the result of a second local landslide source here we test whether a single slow earthquake source can explain the tsunami run up using a combination of new detailed data in the region of the largest run ups and comparison with modelled run ups for a range of plausible earthquake source models using high resolution satellite imagery spot 5 and quickbird the coastal impact of the tsunami is refined in the surroundings of the high security permisan prison on nusa kambangan island where 20 m run up had been recorded directly after the event these data confirm the extreme inundation lengths close to the prison and extend the area of maximum impact further along the nusa kambangan island about 20 km of shoreline where inundation lengths reach several hundreds of metres suggesting run up as high as 10 15 m tsunami modelling has been conducted in detail for the high run up permisan area nusa kambangan and the pltu power plant about 25 km eastwards where run up reached only 4 6 m and a video recording of the tsunami arrival is available for the permisan prison a high resolution dem was built from stereoscopic satellite imagery the regular basin of the pltu plant was designed using photographs and direct observations for the earthquake s mechanism both static infinite and finite kinematic ruptures are investigated using two published source models the models account rather well for the sea level variation at pltu showing a better agreement in arrival times with the finite rupture and predict the permisan area to be one of the regions where tsunami waves would have focussed however the earthquake models that match the data at ptlu do not predict that the wave heights at permisan are an overall maximum and do not predict there more than 10 m of the 21 observed hence our results confirm that an additional localized tsunami source off nusa kambangan island such as a submarine landslide may have increased the tsunami impact for the permisan site this reinforces the importance for hazard assessment of further mapping and understanding local potential for submarine sliding as a tsunami source added to usual earthquake sources

lituya bay landslide impact generated mega tsunami 50th anniversary on july 10 1958 an earthquake mw 8 3 along the fairweather fault triggered a major subaerial landslide into gilbert inlet at the head of lituya bay on the southern coast of alaska the landslide impacted the water at high speed generating a giant tsunami and the highest wave runup in recorded history the mega tsunami runup to an elevation of 524 m caused total forest destruction and erosion down to bedrock on a spur ridge in direct prolongation of the slide axis a cross section of gilbert inlet was rebuilt at 1 675 scale in a two dimensional physical laboratory model based on the generalized froude similarity a pneumatic landslide tsunami generator was used to generate a high speed granular slide with controlled impact characteristics state of the art laser measurement techniques such as particle image velocimetry piv and laser distance sensors lds were applied to the decisive initial phase with landslide impact and wave generation as well as the runup on the headland piv provided instantaneous velocity vector fields in a large area of interest and gave insight into kinematics of wave generation and runup the entire process of a high speed granular landslide impact may be subdivided into two main stages a landslide impact and penetration with flow separation cavity formation and wave generation and b air cavity collapse with landslide run out and debris detrainment causing massive phase mixing formation of a large air cavity similar to an asteroid impact in the back of the landslide is highlighted a three dimenional pneumatic landslide tsunami generator was designed constructed and successfully deployed in the tsunami wave basin at osu the lituya bay landslide was reproduced in a three dimensional physical model at 1 400 scale the landslide surface velocities distribution was measured with piv the measured tsunami amplitude and runup heights serve as benchmark for analytical and numerical models

twentieth century proxy records of temperature and soil organic matter input in the drammensfjord southern norway abstract the drammensfjord in southern norway is an enclosed anoxic basin with a laminated sedimentary record the fjord is a transition area between the marine and terrestrial environments and thus its sedimentary archive contains information on both environments in order to reconstruct recent environmental changes in southern norway two sediment cores covering the last 90 years were analyzed we used the branched versus isoprenoid tetraether bit index as an indicator of terrestrial organic mater input and compared it to the stable carbon isotopic composition of total organic carbon 13 c toc the 13 c toc and bit index show opposing trends with 13 c toc indicating an increase in terrestrial input while the bit index suggests a decrease towards the present this contradiction is probably due to the different sources reflected by 13 c toc vegetation soil and anthropogenic input and the bit index only soil organic matter input in addition an increase in the recycling of respired co 2 within the fjord s water column could have depleted the 13 c toc of the marine component towards more negative values thus seemingly indicating an increase in terrestrial input whilst the bit index could have been affected by a reduction of riverine input and or an increase in archaeal biomass production the tetraether index of lipids with 86 carbons tex 86 was determined as a proxy for past water surface temperatures while some of the signal could be coming from the chemocline our results suggest that tex 86 indicates surface upper 25 m temperatures moreover tex 86 temperature patterns seem to follow variations in the historical record of averaged spring to fall oslo air temperature relatively closely suggesting the signal is produced during this period therefore tex 86 temperature records of fjord sediment cores can potentially be a useful tool in reconstructing past variations of coastal climates

prodigious submarine landslides on the hawaiian ridge the extensive area covered by major submarine mass wasting deposits on or near the hawaiian ridge has been delimited by systematic mapping of the hawaiian exclusive economic zone using the side looking sonar system gloria these surveys show that slumps and debris avalanche deposits are exposed over about 100 000 km2 of the ridge and adjacent seafloor from kauai to hawaii covering an area more than 5 times the land area of the islands some of the individual debris avalanches are more than 200 km long and about 5000 km3 in volume ranking them among the largest on earth the slope failures that produce these deposits begin early in the history of individual volcanoes when they are small submarine seamounts culminate near the end of subaerial shield building and apparently continue long after dormancy consequently landslide debris is an important element in the internal structure of the volcanoes the dynamic behavior of the volcanoes can be modulated by slope failure and the structural features of the landslides are related to elements of the volcanoes including rift zones and fault systems the landslides are of two general types slumps and debris avalanches the slumps are slow moving wide up to 110 km and thick about 10 km with transverse blocky ridges and steep toes the debris avalanches are fast moving long up to 230 km compared to width and thinner 0 05 2 km they commonly have a well defined amphitheater at their head and hummocky terrain in the lower part oceanic disturbance caused by rapid emplacement of debris avalanches may have produced high level wave deposits such as the 365 m elevation hulopoe gravel on lanai that are found on several islands most present day submarine canyons were originally carved subaerially in the upper parts of debris avalanches subaerial canyon cutting was apparently promoted by the recently steepened and stripped slopes of the landslide amphitheaters

numerical modelling of a landslide generated tsunami the 1979 nice event on the 16th of october 1979 a part of the nice new harbour extension close to the nice international airport french riviera slumped into the mediterranean sea during landfilling operations a submarine slide with initial volume close to seashore of about 10 millions m3 which could have evolved later into an avalanche was followed by a small tsunami noticed by several witnesses in the baie des anges the maximum tsunami effects were observed 10 km from the slide location near antibes city which was inundated previous analyses used rough approximate methods and produced models which did not conveniently fit data in this paper both the slide and the generated water waves are numerically simulated on the basis of the shallow water approximation the landslide is assimilated to a heavy newtonian homogeneous fluid downslope under gravity water waves are generated by sea bottom displacements induced by the landslide taking into account a very accurate multibeam bathymetric map the nice slide of 10 millions m3 is simulated by this model the numerical results are generally consistent with the observed hydraulic local effects in front of the nice airport however they are not in agreement in the far field a larger and deeper landslide 2 km off nice airport is tested to quantitatively study the effects of the landslide volume on water waves generation

near field modeling of the july 17 1998 tsunami in papua new guinea modest earthquakes may trigger large submarine landslides responsible for disastrous tsunami waves as demonstrated by the papua new guinea event of july 17 1998 the relatively small earthquake was followed by unexpectedly high waves up to 15 m wiping out 3 villages and killing more than 2200 people numerical simulations show that seismic dislocation sources are not energetic enough to reproduce the observed tsunami along the coast tsunami generation by a submarine landslide has been simulated by a finite difference model assimilating the landslide to a flow of granular material long wave approximation is adopted for both water waves and the slide numerical results show that observed inundation heights are well reproduced for a volume of 4 km located 20 km offshore sliding downslope with a coulomb type friction

distribution and formation of okhotsk sea intermediate water an analysis of isopycnal climatological data 1 in order to clarify the distribution and formation of okhotsk sea intermediate water osiw an isopycnal climatological data set based on all of the available historical observations is developed and examined the isopycnal maps clearly show that there are two direct ventilation sources for osiw dense shelf water dsw with cold and fresh properties influenced by sea ice formation in the northwest shelf region and forerunner of soya warm current water fscw which has warm and saline properties originating in the japan sea the cold and fresh water extends southward from the northwest shelf to the shelf slope off sakhalin island it suggests that dsw is transported southward by the east sakhalin current the dsw enters the kuril basin and mixes with fscw and western subarctic water wsaw originating from the north pacific to form osiw the annual mean production rate of dsw estimated from the total volume of dsw over the shelf in spring and summer is 0 67 sv 1 sv 106 m3 s the annual mean volume transport of fscw is estimated to be 0 08 sv on the basis of its cross section area and the current speed assumption of isopycnal mixing yields a mixing ratio of 1 1 0 1 among dsw wsaw and fscw to form osiw we estimate the annual production rate of osiw to be 1 4 sv the corresponding osiw s renewal time is 7 years continued assumption of isopycnal mixing yields a mixing ratio of 0 6 0 4 between wsaw and osiw to form oyashio intermediate water oyiw

ore fluids of orogenic gold deposits of the gurupi belt brazil a review of the physico chemical properties sources and mechanisms of au transport and deposition

fluid inclusion and stable isotope o h c and s constraints on the genesis of the serrinha gold deposit gurupi belt northern brazil the serrinha gold deposit of the gurupi belt northern brazil belongs to the class of orogenic gold deposits the deposit is hosted in highly strained graphitic schist belonging to a paleoproterozoic 2 160 ma metavolcano sedimentary sequence the ore zones are up to 11 m thick parallel to the regional nw se schistosity and characterized by quartz carbonate sulfide veinlets and minor disseminations textural and structural data indicate that mineralization was syn to late tectonic and post metamorphic fluid inclusion studies identified early co2 ch4 n2 and co2 ch4 n2 h2o nacl inclusions that show highly variable phase ratios co2 homogenization and total homogenization temperatures both to liquid and vapor interpreted as the product of fluid immiscibility under fluctuating pressure conditions more or less asso ciated with postentrapment modifications the ore bearing fluid typically has 18 33mol of co2 up to 4mol of n2 and less than 2mol of ch4 and displays moderate to high densities with salinity around 4 5wt nacl equiv mineralization occurred around 310 to 335 c and 1 3 to 3 0 kbar based on fluid inclusion homogenization temperatures and oxygen isotope thermometry with estimated oxygen fugacity indicating relatively reduced conditions stable isotope data on quartz carbonate and fluid inclusions suggest that veins formed from fluids with 18 oh2o and dh2o 310 335 c values of 6 2 to 8 4

the structure of shear related vein type gold deposits a review abstract the structure of vein type gold deposits is defined by the shapes and geometrical relationships of mineralized bodies the form of the mineralization making up these bodies and the sequence of vein forming events most mineralized zones occur within or are spatially associated with shear zones especially shear zones in larger systems of intersecting shear zone sets they range in shape from tabular to linear and in form from disseminated to breccia to stockwork or sheeted veinlet zones to single veins there typically is a complex history of mineral deposition which overlaps and is genetically related to the deformation that generated the host structural zone the purpose of this paper is to consider the structural features of vein type deposits in relation to the geometrical properties and evolution of veinhosting fractures particularly shear zones the evidence indicates that veins are localized by tectonically generated dilatancy in an environment of low mean stress caused by high fluid pressure it is proposed that a major cause of tectonic dilation of shear zones is the interference between intersecting shears during bulk inhomogeneous flattening by movement on systems of intersecting shear zone sets

source discriminants for near field tsunamis summary we present numerical simulations of tsunami run up in the near field for a data set of 72 models of sources involving both seismic dislocations and landslides by varying one by one the parameters describing the source and the receiving beach we are able to separate their individual influence on the amplitude and distribution of run up which we characterize by forming several dimensionless parameters principally the ratio i 2 of its maximum amplitude to its lateral extent along the beach we find that i 2 remains less than 10 4 for seismic dislocation sources but is greater than this threshold for all physically realistic models of underwater landslides thus it can be used as a discriminant for the nature of the source of a near field tsunami for seismic dislocations we also consider the ratio i 1 of maximum run up to seismic slip on the fault plane and validate numerically the previously suggested rule of thumb that this ratio cannot be much greater than 1 in the case of underwater landslides we show that the distribution of near field run up is primarily controlled by the 2 d wall of water displaced on the ocean surface as an initial condition to the simulation and is practically independent of its extension in the third dimension perpendicular to the beach we apply this approach to nine profiles of tsunami run up obtained experimentally during recent field surveys and show that our method successfully identifies the 1998 papua new guinea tsunami as having been generated by an underwater landslide thus confirming the results of shipboard and hydroacoustic investigations it also strongly suggests a similar mechanism for the generation of the near field aleutian tsunami of 1946 april 1