factors affecting the magnetic susceptibility of baked rocks above a burned coal seam abstract magnetic susceptibility was determined for ninety nine mixed sandstone siltstone and shale samples collected above a burned coal seam near kemmerer wyoming magnetite is the predominant ferrimagnetic mineral present magnetic susceptibility of unbaked sedimentary rocks from this location is quite low o 2 10 5 atm in contrast the massive siltstones with low permeabilities have larger magnetic susceptibilities because the oxidizing gases do not penetrate the rocks large magnetic susceptibilities were also recorded along the edges of the burns and in vents used by escaping volatiles and were probably caused by reduction of hematite during the final stages of combustion in response to a decrease in the oxygen fugacity

nd and sr isotopic variations in acidic rocks from japan significance of upper mantle heterogeneity initial nd and sr isotopic ratios have been measured for cretaceous acidic and related intermediate rocks 24 volcanic and two plutonic rocks from the inner zone of southwest japan izswj to investigate the genesis of acidic magmas the initial nd and sr isotopic ratios for these rocks show three interesting features 1 end values for acidic rocks 2 to 9 are negatively correlated with esr values 10 to 90 together with those for intermediate rocks end 3 to 8 esr 0 to 65 2 the end values for silica rich rocks 60 sio2 correlate with the longitude of the sample locality decreasing from west to east in a stepwise fashion four areas characterized by uniform end values are discriminated 3 low silica rocks 60 sio2 in a certain area have distinctly different end values from those of the high silica rocks in the same area

nd and sr isotope systematics of miocene to holocene volcanic rocks from southwest japan volcanism since the opening of the japan sea isotope nd and sr and geochemical data for twelve volcanic rocks from the shimane oki san in region of southwest japan give some insight into the miocene recent volcanic history of southern japan since rifting from the asian mainland the oldest rocks examined dolerites and ushikiri formation were erupted during the opening of the japan sea at about 15 ma and comprise arc tholeiites derived from a depleted source end 0 esr 0 interpreted in terms of a depleted mantle source modified by a slab derived fluid volcanics of oki dozen island in the japan sea are alkalic derived from an enriched mantle plume isotopically distinct from nearly oki dogo island eruption of the calc alkaline wakurayama andesite early pliocene and both arc and within plate type basalts 1 ma show that magmas were tapped from a variety of sources taking into account plate tectonics and seismic data the subduction influence until the quaternary was the pacific plate with philippines sea plate subduction affecting quaternary and younger volcanics

liquefaction resistance of soils from shear wave velocity a simplified procedure using shear wave velocity measurements for evaluating the liquefaction resistance of soils is presented the procedure was developed in cooperation with industry researchers and practitioners and evolved from workshops in 1996 and 1998 it follows the general format of the seed idriss simplified procedure based on standard penetration test blow count and was developed using case history data from 26 earthquakes and 70 measurement sites in soils ranging from fine sand to sandy gravel with cobbles to profiles including silty clay layers liquefaction resistance curves were established by applying a modified relationship between the shear wave velocity and cyclic stress ratio for the constant average cyclic shear strain suggested by r dobry these curves correctly predicted moderate to high liquefaction potential for 95 of the liquefaction case histories and are shown to be consistent with the standard penetration test based curves in sandy soils a case study is provided to illustrate application of the procedure additional data are needed particularly from denser soil deposits shaken by stronger ground motions to further validate the simplified procedure

nonlinearity liquefaction and velocity variation of soft soil layers in port island kobe during the hyogo ken nanbu earthquake clear nonlinear behavior is analyzed from the acceleration records of the 1995 hyogo ken nanbu earthquake at port island kobe from four triaxial in struments placed at four different depths the surficial effects during strong ground motions were compared with those during weak motions before and after the main shock we used a spectral ratio technique and a nonlinear inversion for velocity structure to analyze the data from the spectral analysis we observed a large variation of the spectral ratios between the surface and different depths during the strong ground motions and during the liquefied state the spectral ratios after the mainshock i e after the liquefied state are different from those before the mainshock the peak frequencies in the spectral ratios after the mainshock are shifted to lower fre quencies with respect to those in the spectral ratios before the mainshock we in verted the s wave velocities using a genetic algorithm technique to determine the velocity structure before during and after the mainshock the s wave velocity struc ture before and after the mainshock was found to be different specifically the s wave velocity of the second layer 5 m to 16 m depth after the mainshock was 20 lower than before our analysis shows that the liquefied state remains at least 3 hr after the mainshock but no more than 24 hr the rigidity of the soil decreased close to zero when liquefaction happened and later increases gradually following a trend that resembles a consolidation curve the strong influence of nonlinearity during the mainshock yielded a big reduction of the horizontal surface ground motions so that the observed horizontal peak acceleration was only about 25 of the peak acceler ation expected from the linear theory however the nonlinear effects in the vertical peak acceleration were not significant

origin of high magnesian andesites in the setouchi volcanic belt southwest japan ii melting phase relations at high pressures melting phase relations of an augite olivine high magnesian andesite and an augite olivine basalt from the miocene setouchi volcanic belt in southwest japan have been studied under water saturated water undersaturated and under anhydrous conditions both the andesite and the basalt are characterized by low feo mgo ratios 0 86 and 0 76 in weight respectively and qualify as primary magmas derived from the upper mantle the andesite melt coexists with olivine orthopyroxene and clinopyroxene at 15 kbar and 1030 c under water saturated conditions and at 10 kbar and 1070 c under water undersaturated conditions 7 wt h2o in the melt the basalt melt also coexists with the above three phases at 11 kbar and 1305 c under anhydrous conditions and at 15 kbar and 1205 c in the presence of 4 wt water present studies indicate that high magnesian andesite magmas may be produced even under water undersaturated conditions by partial melting of mantle peridotite it is suggested that two types of high magnesian andesites in the setouchi volcanic belt augite olivine and bronzite olivine andesites were produced by different degrees of partial melting augite olivine andesite magmas whose mantle residual is lherzolite were formed by lower degrees of partial melting than bronzite olivine andesite magmas which coexist with harzburgite the basalt magmas which were often extruded in close proximity to the high magnesian andesite magmas are not partial melting products of a mantle peridotite which had previously melted to yield high magnesian andesite magmas

two case histories demonstrating the effect of past earthquakes on liquefaction resistance of silty sand abstractthe paper compares two liquefaction case histories in california 1 the response of the wildlife site in the imperial valley to the 2010 el mayor cucapah earthquake mw 7 2 amax 0 15 g

evaluation of liquefaction resistance for gravelly sands using gravel content corrected shear wave velocity abstractthe current practice of evaluating the liquefaction resistance of gravelly soils with shear wave velocity relies on the assumption that liquefiable gravelly soils behave as sandy ones recent laboratory tests on gap graded gravelly sands show that the cyclic resistance is dominated by the packing conditions of the sand matrix while the shear wave velocity is affected by the gravel content taking these findings into account the gravel content corrected shear wave velocity is derived based on the time average equation of lumped gravel particles and the sand matrix based on analyses of case histories a three step procedure which includes screening of gravelly sands computation of stress normalized gravel content corrected shear wave velocity and cyclic resistance evaluation using the modified correlation between the corrected shear wave velocity and the cyclic resistance is proposed for evaluating the cyclic resistance ratio of gravelly sands comparisons with case histories show that the p

accounting for soil aging when assessing liquefaction potential it has been recognized that liquefaction resistance of sand increases with age due to processes such as cementation at particle contacts and increasing frictional resistance resulting from particle rearrangement and interlocking as such the currently available empirical correlations derived from liquefaction of young holocene sand deposits and used to determine liquefaction resistance of sand deposits from in situ soil indices standard penetration test spt cone penetration test cpt shear wave velocity test vs are not applicable for old sand deposits to overcome this limitation a methodology was developed to account for the effect of aging on the liquefaction resistance of old sand deposits the methodology is based upon the currently existing empirical boundary curves for holocene age soils and utilizes correction factors presented in the literature that comprise the effect of aging on the in situ soil indices as well as on the field cyclic strength crr this paper describes how to combine currently recorded spt cpt and vs values with corresponding crr values derived for aged soil deposits to generate new empirical boundary curves for aged soils the method is illustrated using existing geotechnical data from four sites in the south carolina coastal plain sccp where sand boils associated with prehistoric earthquakes have been found these sites involve sand deposits that are 200 000 to 450 000 years in age this work shows that accounting for aging of soils in the sccp yields less conservative results regarding the current liquefaction potential than when age is not considered the modified boundary curves indicate that old sand deposits are more resistant to liquefaction than indicated by the existing empirical curves and can be used to evaluate the liquefaction potential at a specific site directly from the current in situ properties of the soil

crustal history of the rae and hearne provinces southwestern canadian shield saskatchewan constraints from geochronologic and isotopic data abstract the cree lake zone hearne province and western granulite domain rae province in northern saskatchewan are contrasting parts of the variably reworked upper plate western hinterland of the paleoproterozoic trans hudson orogen their junction is defined by the virgin river shear zone a part of the more extensive snowbird tectonic zone subsurface extension of the 2 0 ga thelon orogen lies west of the western granulite domain we present u pb zircon ages sm nd and rb sr isotopic data from the cree lake zone and western granulite domain and from the junction granite which intrudes the virgin river shear zone data from the western granulite domain indicate that prevalent granulite facies metamorphism occurred between 2 3 and 2 0 ga but is imposed on archean protoliths 2 8 3 0 ga old low amphibolite facies retrogression which increases toward the virgin river shear zone probably postdates 2 1 ga data from the cree lake zone also yield archean protolith ages as old as 3 0 ga and some rocks yield interpreted high grade metamorphic overprint ages of 2 3 2 0 ga however two samples yield data indicating hudsonian high grade metamorphic overprint 1 87 to 1 81 ga the junction granite has a u pb zircon age of 1 82 0 30 ga but relict zircons and sm nd data show that it was derived by melting of archean crust high grade mid crustal thermal resetting in the western granulite domain may be coeval with the 1 9 2 0 ga thelon orogen although the data do not preclude an earlier event or events similar 2 3 2 1 ga reworking extends into the cree lake zone but high grade hudsonian 1 87 1 84 ga reworking is also evident in parts of this zone well to the west of the wollaston domain and may extend entirely across the zone to the virgin river shear zone relative importance of the thelon and hudsonian overprints in cree lake zone is unknown data from the junction granite and western granulite domain suggest that all recorded high strain events in the virgin river shear zone postdate 2 3 ga and are thus unrelated to deep crustal archean granulite facies mylonites in the tantato black lake segment of the snowbird tectonic zone north of the athabasca basin

centrifuge modeling of the effect of preshaking on the liquefaction resistance of silty sand deposits abstractfield observations suggest that preshaken natural sands in some seismic regions have high liquefaction resistance as a result of geologic aging and or preshaking this paper focuses on the young silty sand deposits located in the imperial valley of california recent deposition and intense seismic activity in the valley suggest that preshaking is the main cause of their increased liquefaction resistance the first part of the paper examines the liquefiable layer at the wildlife site which may have been deposited by flooding approximately between 1905 1907 the site was instrumented with accelerometers and piezometers in 2005 providing data over the last 10 years the following conclusions are reached from this and from the catalog information on earthquakes before 2005 1 since 1907 the wildlife layer has been subjected to approximately 60 70 earthquakes having amax 0 1 g at the site which caused pore pressure buildup in the layer 2 most of these earthquakes generated excess pore pressur

comparison of methods to estimate the rate of co2 emissions and coal consumption from a coal fire near durango co abstract subsurface fires in coal beds consume coal resources and contribute to the global emissions of co2 and air pollutants many of these fires are found in china india indonesia and the united states combustion product gases at these coal fires exit through surface fissures that form over fires these fissures are created when subsurface subsidence causes preexisting fractures in the area to widen fissures act as both inlets for air and exhaust for combustion gases while remote sensing approaches have been used to quantify the rate of coal consumption and co2 emissions at large scale fires that extend over large distances methods for estimating the coal consumption and co2 emissions values based on surface observations are less well established in this paper a coal fire near durango co is described a combination of fissure mapping thermocouple temperatures and a cesium vapor magnetometer survey was used to delineate the aerial extent of the current combustion zone and previously burned zones three methods were then used to estimate combustion rates at an active region at the site in the first method time lapse high resolution topographic surveys were used to relate surface volumetric losses over the active region to coal consumption and rates of co2 emission in the second method measured temperatures gas compositions and dimensions of an exhaust fissure were used in a simple natural convection chimney model to estimate rate values the third method estimated coal consumption and co2 emission rates by measuring the velocity of exhaust gases gas compositions and exhaust fissure dimensions for the second and third methods 13c isotope signatures were used to determine the fractions of co2 that were emitted from coal and ch4 combustion or from co2 in the native gas in the coal seam a flux accumulation chamber was also used to quantify co2 leakage rates from non fissured regions over an active fire region the three methods produced roughly consistent estimates of coal combustion and co2 emission rates

structural metamorphic evolution of late proterozoic ophiolites and precambrian basement in the central asian foldbelt of mongolia abstract the late proterozoic and palaeozoic central asian foldbelt is regarded as one of the best examples which demonstrates that processes of lateral crustal growth and obduction accretion tectonics took place since at least late precambrian times in mongolia the precambrian and early cambrian rocks were formed in two different environments continental and oceanic the archaean to early proterozoic complexes are autochthonous and constitute a metamorphic continental basement the late proterozoic to early cambrian ophiolite complexes represent remnants of obducted oceanic crust and occur as intensely deformed nappes and tectonic melanges overthrust on the older basement during the caledonian orogeny distinctly differentiated tholeiitic calc alkaline and boninite rocks series together with the lithological characteristics of associated volcanogenic sedimentary formations indicate that the mongolian ophiolite complexes were generated in a forearc marginal basin setting the culmination of ophiolite formation occurred in late precambrian to early cambrian time five phases of progressive regional metamorphism have been identified in the basement complex and overlying ophiolite association each of these was accompanied by folding and granitoid plutonism and is characterised by a distinct composition of fluid inclusions

comparing cpt and vs liquefaction triggering methods abstractsignificant developments have taken place over the past 20 years to evaluate the liquefaction potential of soils using in situ tests the cone penetration test cpt is now commonly used to evaluate liquefaction potential in soils there have also been significant developments to evaluate liquefaction potential based on in situ shear wave velocity vs measurements liquefaction methods base on shear wave velocity have the advantage that they are essentially independent of soil characteristics such as fines content but often lack the stratigraphic detail obtained using the cpt liquefaction methods based on the cpt have the advantage of continuous repeatable measurements but require corrections based on soil characteristics that can be significant in soils with high fines content comparing the most recent vs based method with a cpt based method provides an independent evaluation of the associated corrections applied to the cpt based method this paper compares the current vs based method with

laboratory investigation on assessing liquefaction resistance of sandy soils by shear wave velocity shear wave velocity vs offers engineers a promising alternative tool to evaluate liquefaction resistance of sandy soils and the lack of sufficient in situ databases makes controlled laboratory study very important in this study semitheoretical considerations were first given based on review of previous liquefaction studies which predicted a possible relationship between laboratory cyclic resistance ratio crrtx and vs normalized with respect to the minimum void ratio confining stress and exponent n of hardin equation undrained cyclic triaxial tests were then performed on three reconstituted sands with vs measured by bender elements which verified this soil type dependent relationship further investigation on similar laboratory studies resulted in a database of 291 sets of data from 34 types of sandy soils based on which the correlation between liquefaction resistance and vs was established statistically and further converted to equivalent field conditions with well defined parameters reve

numerical modeling for analyzing thermal surface anomalies induced by underground coal fires abstract coal seams burning underneath the surface are recognized all over the world and have drawn increasing public attention in the past years frequently such fires are analyzed by detecting anomalies like increased exhaust gas concentrations and soil temperatures at the surface a proper analysis presumes the understanding of involved processes which determine the spatial distribution and dynamic behavior of the anomalies in this paper we explain the relevance of mechanical and energy transport processes with respect to the occurrence of temperature anomalies at the surface two approaches are presented aiming to obtain insight into the underground coal fire situation in situ temperature mapping and numerical simulation in 2000 to 2005 annual temperature mapping in the wuda inner mongolia pr china coal fire area showed that most thermal anomalies on the surface are closely related to fractures where hot exhaust gases from the coal fire are released those fractures develop due to rock mechanical failure after volume reduction in the seams the measured signals at the surface are therefore strongly affected by mechanical processes more insight into causes and effects of involved energy transport processes is obtained by numerical simulation of the dynamic behavior of coal fires simulations show the inter relation between release and transport of thermal energy in and around underground coal fires our simulation results show a time delay between the coal fire propagation and the observed appearance of the surface temperature signal additionally the overall energy flux away from the burning coal seam into the surrounding bedrock is about 30 times higher than the flux through the surface this is of particular importance for an estimation of the energy released based on surface temperature measurements finally the simulation results also prove that a fire propagation rate estimated from the interpretation of surface anomalies can differ from the actual rate in the seam

fissure formation and subsurface subsidence in a coalbed fire abstract coalbed fires are uncontrolled subsurface fires that occur around the world these fires are believed to be significant contributors to annual co 2 emissions although many of these fires have been burning for decades researchers have only recently begun to investigate physical mechanisms that control fire behavior one aspect of fire behavior that is poorly characterized is the relationship between subsurface combustion and surface fissures at the surface above many fires long wide fissures are observed at a coalbed fire near durango colorado these fissures form systematic orthogonal patterns that align with regional joints in the upper cretaceous fruitland formation understanding the mechanisms that form these fissures is important as the fissures are believed to play vital roles in sustaining the combustion in the subsurface in some of the coalbed fire simulation models available today these fissures are treated as fixed boundary conditions we argue using data collected field observations and simulation result that there exists a relationship between the location and magnitude of subsidence caused by the fire and the opening of fissures the results presented suggest that fissures are believed to open when subsurface subsidence gives rise to tensile stresses around pre existing joints

cpt based liquefaction case history from the 2012 emilia earthquake in italy abstractsignificant and widespread liquefaction phenomena were observed after the main shock of the emilia earthquake italy on may 20 2012 a considerable number of surveys were subsequently performed to accurately test the susceptibility to liquefaction of soil deposits affected by the most severe liquefaction induced effects and damage ground surface morphology was defined in detail by means of lidar survey results subsoil stratigraphy and water table level were inferred from cpt tests and soundings physical properties and mechanical parameters of soils were obtained from laboratory tests or indirectly inferred from the results of a large number of cpt tests carried out in the area two main sandy layers susceptible to liquefaction were identified and appropriately characterized seismic loading induced by the main shocks of the sequence was carefully estimated from the peak ground acceleration map produced by the national institute of geophysics and volcanology more than 90 sites were examined i

response of heterogeneous rainfall variability in east asia to hadley circulation reorganization during the late quaternary abstract the quaternary east asian summer rainfall evolution reconstructed with the chinese speleothem 18o records shows the consistency throughout the region of east asia and has long been considered equivalent to the monsoon intensity its variation and teleconnection with global climate were usually interpreted by the meridional shift of the intertropical convergence zone itcz however many other proxy records climate simulations and meteorological observations suggest the inconsistent rainfall patterns in the different regions of east asia on multi timescales such spatial heterogeneity in quaternary east asian summer rainfall indicates that the hydroclimate in this region is not fully paced by the migration of the itcz here we report a sediment record of rainfall evolution during the last 400 ka in the northern east china sea and this record in combination with a transient climate model simulation indicates an out of phase relationship between rainfall over middle southeastern east asia and northern and southwestern east asia on the precession band with high boreal summer insolation corresponding to the increased rainfall intensity in the northern and southwestern east asia however decreased rainfall intensity in the middle east asia we attribute this regional heterogeneity in east asian rainfall to the reorganization of the hadley circulation including shifts in the ascending branch itcz and descending branch subtropical westerly jet in response to changes in the hemispheric meridional temperature gradient our results highlight the crucial role of the hadley circulation in the east asian hydroclimate and have important implications for future climate projections

nd and sr isotopic constraints on the origin of igneous rocks resulting from the opening of the japan sea southwestern japan strontium and nd isotopic compositions and trace element abundances were determined for cretaceous to late cenozoic igneous rocks from the japan sea side of southwest japan in order to investigate the effect of the opening of the japan sea on igneous activity the 87sr 86sr ratios for both high and low silica rocks decrease with decreasing age since the middle miocene when the opening occurred similarly 143nd 144nd values for these rocks increase with decreasing age and are negatively correlated with 87sr 86sr ratios a two component mixing process can best account for these isotopic and chemical characteristics one end member is likely the subcontinental lithospheric mantle sclm and its derivative mafic to intermediate materials which had nd values of around 3 the other endmember consists of mafic to intermediate rocks with low nd values e g 8 probably located in the lower crust the mantle upwelling associated with the opening of the japan sea did not supply typical morb or morb source materials to the crust but did provide the heat that caused the melting of lithospheric mantle and lower crust

liquefaction potential assessment of a region using different techniques tepebasi eskisehir turkey abstract eskisehir is a city in turkey that is located primarily on the porsuk river alluvium deposits hence the probability of liquefaction is a geotechnical problem in this city in this study the liquefaction potential was investigated using a standard penetration test spt and downhole geophysical test menard pressuremeter tests were also performed in order to modify liquefaction analysis methods with this test laboratory tests were performed on standard penetration split sampler samples collected from the boreholes liquefaction analysis was performed considering different scenarios the first peak horizontal acceleration value was determined from the earthquake that occurred in 1956 which was 6 4 mw the second peak horizontal acceleration value was determined from cukurhisar sultandere fault which is approximately 40 km long and may create a 6 94 mw earthquake with a peak horizontal acceleration of amax 0 48 g there are some differences between spt n method and vs method but both the spt n method and the vs method are harmonious with each other in general for determination of the liquefable soils the vs method particularly results in a continuous profile for the liquefaction determination there is no regional liquefaction potential in the study region but locally liquefiable silty sand layers were determined the liquefable layer thickness increases with increasing peak horizontal acceleration a liquefaction analysis method using the menard pressuremeter test is suggested in this study both the cyclic resistance ratio crr chart and the equation are modified for liquefaction analysis using the menard pressuremeter test

liquefaction at moss landing during loma prieta earthquake a study of liquefaction at five sites in the moss landing area during the 1989 loma prieta earthquake is presented results of this case history study include 1 a large set of cone penetration test cpt data for sites where evidence of liquefaction was and was not observed 2 information regarding the influence of thin soil strata on overall site behavior 3 inclinometer data on deformations at depth due to lateral spreading of a shoreline 4 a description of the apparent liquefaction of a marshland clayey silt deposit 5 seismic shear wave velocity data at sites where evidence of liquefaction was and was not observed and 6 an evaluation of how interpretation methods affect the development and use of cpt based liquefaction correlations

existence of andesitic primary magma an example from southwest japan a high magnesian andesite sio2 58 50 mgo 9 47 occurs at teraga ike in southwest japan it belongs to the setouchi volcanic rocks of middle miocene age and carries olivine and bronzite as phenocrysts 4 2 and 1 4 modal percent respectively this andesite is characterized by mg values as high as 75 suggesting that it may be a primary andesite olivine phenocrysts fo87 91 are in equilibrium with the groundmass liquid on the basis of fe mg exchange partitioning between olivine and liquid and they have high nio contents up to 0 45 chromite inclusions in olivine and rarely bronzite have high cr2o3 contents max 54 87 these features strongly suggest that the teraga ike andesite keeps the chemical composition of the primary magma generated in the upper mantle and therefore verify the existence of primary andesite magmas

open system magmatic evolution of andesites and basalts from the salmon creek volcanics southwestern idaho u s a abstract the salmon creek volcanics scv comprise 31 26 ma orogenic andesites and mildly alkaline basalts detailed petrologic and geochemical studies of two thick continuous sections of scv lavas reveal cyclic compositional variations apparently produced by a systematic progression of magmatic processes through time the earliest phase of scv activity produced basalts with trace element and isotopic compositions indicating an asthenospheric source enriched in subduction related components following eruption of these basalts an andesitic magma chamber was established within the continental crust near the base of the thickest andesite section compositions of the lavas become more mafic upsection indicating high rates of magma recharge relative to crystallization wall rock assimilation was most significant in the earliest stages of magma chamber initiation and growth as shown by the sharp increase in alkalies and covariant changes in sr pb and nd isotopes in the lowermost andesite lavas further upsection compositional variations in the andesites are more consistent with fractional crystallization as the predominant magmatic process observed phenocryst assemblages in the andesites and mass balance calculations indicate that crystallization was dominated by kaersutitic hornblende with relatively little plagioclase hornblende dominated assemblages suggest that the magmas were hydrous 2 h 2 o in the melt and evolved at moderate pressures in the lower to middle crust 3 15 kbar

earthquake induced liquefaction features in a late quaternary fine grained lacustrine succession fucino lake italy implications for microzonation studies abstract the fucino lacustrine basin in central italy is a large flat area mostly devoted to agriculture with urbanization along the perimeter of the ancient lake in 1915 a strong earthquake struck the area mw 7 0 producing large damages and geological effects including surface faulting ground failures and liquefaction a channel excavated in the lacustrine sediments exposed ground failure with dykes of fine grained sediment that we interpret as the result of earthquake induced liquefaction we present the results of a multidisciplinary work aimed at characterizing in detail the geology of the buried stratigraphic succession its susceptibility to liquefaction and the likely source of the fine grained liquefied material the succession down to 20 m deep is formed by fine grained sediments younger than 170 180 kyrs mostly late pleistocene holocene prevailingly silt or silt clay mixtures the geological field analysis indicates that the dykes are filled by prevailing silt liquefied and transported by upward directed flow of short duration as for earthquake induced liquefaction tilting and lateral spreading accompanied the process the overall liquefaction potential derived from the simplified methods is high correlations of x ray powder diffraction mineralogy of samples from drilling cores with those from dykes allowed us to identify the most likely source layer filling dykes corresponding to a silt layer at 7 8 m depths this layer and the dykes lack illite and montmorillonite clay particles these results contribute to improve studies of liquefactions in sediments that differ from typical liquefiable loose sands they have also implications for microzonation studies most samples show grain size curves that do not fit within the field of potentially liquefiable soils suggesting that criteria based on grain size can be poorly significant in seismic microzonation studies of recent late pleistocene holocene lacustrine fine grained successions

anisotropy of small strain stiffness in ticino sand comprehensive tests performed in a large calibration chamber and consisting of the propagation of seismic body waves in dry ticino silica sand are presented by virtue of the fact that both shear and constrained compression waves have been propagated in vertical horizontal and oblique directions five independent constants of the cross anisotropic elasticity model of the test have been established the tests have also made it possible to evaluate the influence of the structural inherent and stress induced anisotropy on the velocity of the propagated seismic body waves the influence of the principal effective stresses on the velocity of these waves is also described de nombreux essais realises dans une grande chambre d etalonnage et consistant en la propagation d ondes sismiques dans des sables siliceux et sec de ticino sont presentes les ondes de cisaillement et de compression ayant w emises dans des directions verticales horizontales et obliques les 5 constantes independantes du modele eastique

cyclic shear strain needed for liquefaction triggering and assessment of overburden pressure factor kσ abstractthis paper has two objectives the first is to evaluate the cyclic shear strain needed to trigger liquefaction cl in clean and silty sands in the field during earthquakes as an alternative to the currently used cyclic resistance ratio crr the second objective is to explore the effect of a high effective overburden pressure v0 on the value of crr the first objective is accomplished mainly by using an equation relating cl and crr valid for shear wave velocity based liquefaction charts this equation is supplemented with laboratory results from undrained cyclic strain controlled tests as well as large scale and centrifuge model shaking experiments it is shown that for recent uncompacted clean and silty sand deposits and earthquake magnitude mw 7 5 cl 0 03 with this value increasing to cl 0 3 in some cases to 0 6 in denser and overconsolidated preshaken and compacted sands these small values of cl in the field are controlled by two factors excess pore pressure buildup in the

shear wave velocity as function of cone penetration test measurements in sand and silt mixtures abstract a database of research quality piezocone test cptu results and shear wave velocity v s measurements assembled in the context of an ambitious research project carried out at the treporti test site venice italy has been interpreted in order to study the seismic response of the predominantly silty sediments forming the venetian lagoon basin as well as to explore potential correlations for such intermediate soils the experience gained so far with the treporti database and other field data collected in the lagoon area has shown that the mechanical behavior of venetian soils cannot be easily interpreted using the existing and well established cptu based approaches hence the interest in examining whether or not the seismic response of these sediments expressed in terms of shear wave velocity follows the framework published for other soils the applicability to the available data of a number of existing correlations originally developed either for sands or fine sediments has been first investigated and updated relationships have been then suggested furthermore the small strain stiffness calculated from v s measurements has been compared with the field stiffness derived from the observed performance of a full scale test embankment built in the treporti site so as to verify common design assumptions the verification and calibration of existing approaches are likely to constitute a useful contribution to the practice of geotechnics not only in the venetian lagoon area but also in the silty deposits usually present in the surrounding alluvial plain and other similar depositional environments allowing rapid estimates of seismic soil classification as well as small strain stiffness properties for preliminary design or at sites where only cone penetration data are available

origin of high magnesian andesites in the setouchi volcanic belt southwest japan i petrographical and chemical characteristics high magnesian andesites of middle miocene age occur in southwest japan forming an obvious volcanic belt these andesites have low feo mgo ratios 0 546 0 931 and are rich in ni 101 312 ppm co 30 0 45 1 ppm and cr 208 756 ppm they are relatively aphyric phenocrysts 10 vol and the phenocrysts of magnesian olivine fo88 are in equilibrium with the host high magnesian andesite magmas on the basis of the fe mg exchange partitioning these features suggest that the high magnesian andesites are not differentiated or accumulative they appear to represent primary andesites generated in the upper mantle these southwest japanese high magnesian andesites are rich in incompatible elements and show light rare earth enrichment relative to boninites suggesting that the former is derived from a less depleted mantle source than the latter

nd and sr isotopic study of volcanic rocks from japan two older granitic rocks and some selected quaternary volcanic rocks from the japanese islands were analyzed in a reconnaissance study for the purpose of examining the relationships between nd and sr isotopic abundances and the megatectonic structure around the japanese islands model ages of 0 9 ae were determined by the nd and sr methods on a paleozoic gneiss which confirms that a relatively ancient acidic basement exists in the japanese islands the nd and sr isotopic data show that the cretaceous granodiorite is the result of partial melting of older crust the nd of tholeiitic rocks from the izu arc gives e nd ranging from 8 3 to 9 3 and with the corresponding e sr from 14 5 to 18 5 these results are identical to those found for the mariana arc these values are distinctly lower than typical morb by around 1 2 eu this difference in e nd between arcs and morb is attributed to the contribution of oceanic sediments to the partial melts produced during subduction of oceanic crust the hakone volcano is clearly confirmed as belonging to an oceanic source by nd isotopic results e sr e nd values of the volcanics from a section along the fossa magna show a clear indication that they are a blend of oceanic mantle material and continental crustal material the crustal component clearly increases in going from south to north volcanics across the northeast japan arc also show a distinct correlation of e sr e nd related to the position relative to the active subduction zone but with the opposite trend these relationships of the present isotopic pattern and the zonal arrangement relative to the subduction zone suggest the former existence of a local spreading center in the japan sea in general there appear to be regular isotopic relationships between the izu mariana oceanic island arc and the continental island arc of japan which indicates that partially melted or assimilated older continental basement is admixed with young rising oceanic arc magmas

a contribution of slab melts to the formation of high mg andesite magmas hf isotopic evidence from sw japan 1 hf isotope ratios were measured for high mg andesites hma and basalts from the setouchi volcanic belt southwest japan in order to examine whether fluid or melt from subducted slabs act as metasomatic agents for hma magma genesis since hf is one of the incompatible elements that may not be readily transported by aqueous fluids hf isotopes should provide strong constraints on the origin of such slab derived components setouchi hmas and basalts are distinct in their lower 176hf 177hf ehf 13 suggesting significant contribution of subducted sediments to setouchi magma genesis it should be further stressed that hf isotopes are well correlated with sr nd isotopes and la nb ratios among the setouchi magmas geochemical modeling suggests that such characteristics can be best explained by addition of slab derived components with sediment melts rather than aqueous fluids to the hma source

coal fires revisited the wuda coal field in the aftermath of extensive coal fire research and accelerating extinguishing activities abstract the wuda coal mining area in inner mongolia autonomous region china is one of the largest coal fire areas world wide at the same time it is also one of the most extensively researched ones the sub surface coal fires raging in the underground coal seams of the syncline are located directly west of the town of wuda the fires have been mapped in situ based on remote sensing data as well as based on geo physical survey all throughout the years 2001 to 2005 numerous publications depict the situation during that time in the present study we assess the current situation in wuda coal field five years after the last field campaigns under nowadays on going and accelerating extinguishing activities we present the results of coal fire dynamics assessment based on in situ mappings between 2004 and 2010 the analyses of changes in mining infrastructure between 2005 and 2012 as well as land cover change in the area from 2005 to 2012 newest high resolution multispectral and panchromatic quickbird data as well as time series of quickbird data supported this endeavor we furthermore present the result of semi structured interviews undertaken with members of the local mine directorate of the wuda syncline all jointly analyzed data indicate that the wuda coal fires tend to move eastwards within the syncline meaning that they move along the dip of the coal seams to greater depths furthermore mining related infrastructure is clearly moving from the west to the east as well despite large funds spent on fire extinguishing only few fires remain permanently extinct while other fire areas increase in size the former land cover structure in the arid syncline does not exist anymore extinguishing activities have led to a complete turn over of all material in the region the coal fire problem in wuda area remains a pressing one

reinitiation of subduction and magmatic responses in sw japan during neogene time southwestern japan during paleogene time was affected by subduction of the kula and pacifi c plates beneath the eastern margin of eurasia followed by a brief episode of transform faulting to allow the shikoku basin to open at 27 15 ma subsequent opening of the japan sea back arc basin in middle miocene time broke japan away from eurasia and sw japan rotated clockwise 45o as it drifted south 17 15 ma southward drift required subduction of the philippine sea plate beneath sw japan leading to the formation of a magmatic arc subduction of the hot shikoku basin lithosphere and spreading ridge resulted in distinctive volcanism in the sw japan forearc between 17 and 12 ma this volcanism included midoceanic ridge basalt morb like intrusions and oceanic island basalt oib type alkali basalts felsic plutons in the accretionary prism and high magnesium andesites along the setouchi forearc basin mafi c magmas in the outermost forearc originated from the subducted shikoku basin spreading ridge whereas setouchi high magnesium andesites hma may have resulted from the interaction of melts of the subducted philippine sea plate with the overlying mantle felsic magmas in the forearc resulted from melting of shimanto belt sediments caused by intrusion of hma magmas persistent rear arc volcanism was caused by upwelling asthenosphere associated with opening of the sea of japan rear arc volcanism began ca 25 ma as rift fi ll low alkali tholeiite volcanism and was replaced gradually after 12 ma by alkali basalt volcanism upwelling related alkali volcanism continues up to the present whereas forearc volcanism ceased at 12 ma the volcanic arc narrowed with time as the philippine sea slab descended and slowly cooled adakitic dacites erupted after 1 7 ma above the 100 km depth contour of the subducted philippine sea plate suggesting that melting resulted from interaction of the slab with upwelling asthenosphere interactions between upwelled rear arc asthenosphere and subduction of the hot philippine sea slab appear to have been the main controls of magmatism for the neogene sw japan arc

anomalous intra plate high mg andesites in the choshi area chiba central japan produced during early stages of japan sea opening abstract geochemical and isotopic data are reported for 20 ma high magnesian andesite hma lavas erupted on the forearc side of central japan in the choshi coastal area chiba rarely olivine phyric 345 ppm high sr 520 ppm high sr y ca 30 and high la yb n 8 conforming to the definition of low silica adakites transitional in character to hma however despite slight negative nb and ta troughs in a few samples their incompatible element distribution patterns appear closer to those of intra plate basalts apparently confirming previous suggestions that terms such as hma and adakite cover a diverse range of compositions enriched in radiogenic sr and nd ca 0 7040 to 0 7043 and 0 5128 to 0 51275 respectively the choshi hma shows relatively low 206pb 204pb 18 25 to 18 35 and 208pb 204pb 38 37 to 38 48 ratios resembling those of late miocene intra plate basalts in the japan sea and sw japan in this regard the choshi hma differs from those of the classic middle miocene 14 to 12 ma hma described from the setouchi volcanic belt e g tatsumi 1981 a short distance to the west which also shows relative high k contents although hmas have been generally attributed to subduction related processes the lack of high field strength element hfse depletions cf large ionic lithophile elements lile in most choshi hma suggests an absence of so called subduction signatures accordingly we suggest that the choshi hma probably tapped a fertile asthenospheric region of the convecting mantle wedge primitive melt products having acquired hma like character as a result of shallow level modification by interaction with lithospheric components aided by thermal input resulting from mantle extrusion during the early stages of japan sea opening 23 15 ma

neodymium isotopic composition of quaternary island arc lavas from indonesia abstract 143 nd 144 nd ratios measured in quaternary lavas from java and the banda arc of indonesia range from 0 51242 to 0 51280 and exhibit an inverse correlation with 87 sr 86 sr isotopically the indonesian samples resemble andean rather than island arc lavas the samples from java plot either within or adjacent to the mantle array towards higher 87 sr 86 sr ratios samples from the banda arc and the anomalous calc alkaline volcano papandajan are characterized by relatively low 143 nd 144 nd and high 87 sr 86 sr ratios these characteristics are consistent with the interpretation that subducted terrigenous material was involved in the genesis of these lavas furthermore the banda arc samples appear to lie on a mixing line between isotopic compositions characteristic of the mantle and upper continental crust a high k trachyte from the alkaline volcano muriah java has isotopic characteristics of the mantle 143 nd 144 nd 0 51270 87 sr 86 sr 0 70424 which implies that the extreme enrichment in large ion lithophile elements in its source must have occurred only shortly before its formation the inferred 143 nd 144 nd ratio of the unmodified mantle beneath java and the banda arc is lower than that observed in mid ocean ridge basalt which may have important implications for a better understanding of the geochemical structure of the mantle

magnetometer measurements to characterize a subsurface coal fire underground coal fires pose a threat to the environment and the health of those living in their proximity and can result in economic losses if these fires occur at mining areas design of methods to extinguish these fires requires that the extent of the subsurface fire be delineated a conceptual picture of the workings of a subsurface coal fire near durango co is presented first which shows how the overburden above the burning coal seam can become heated in high temperature and low o2 conditions the heating of the overburden leads to the formation of magnetite and its presence and the alignment of magnetic moments can be detected by a magnetometer magnetometer surveys allow high resolution areal mapping that differentiates among previously burned currently burning and unburned coal seam areas the current and previous locations of the subsurface fire regions that are delineated by the magnetometer survey conducted at a fire on the southern ute indian reservation are consistent with various supporting data such as gas composition temperature and snowmelt data

nd sr systematics of the setouchi volcanic rocks southwest japan a clue to the origin of orogenic andesite abstract twenty three volcanic rocks from the setouchi volcanic belt southwest japan were analyzed for nd and sr isotopic compositions for the purpose of examining the genetic relationships among the basalt high magnesium andesite hma and evolved porphyritic andesite the andesites have higher 87 sr 86 sr 0 70487 0 70537 and lower 143 nd 144 nd 0 512509 0 512731 than the basalts i e 0 70408 0 70468 and 0 512691 0 512830 respectively this result confirms earlier conclusions obtained from petrologic study that the andesites cannot be fractionation products of basaltic magma but that the andesitic and basaltic magmas were generated independently on the basis of melting experiments for hma and basalt it is inferred that there is an isotopically stratified mantle beneath southwest japan evolved porphyritic andesites have essentially identical sr and nd isotopic ratios to hma and can be derived by fractionation of primary andesitic magma a model to produce orogenic andesite is proposed on petrologic experimental and isotopic bases

mantle derived archaean monozodiorites and trachyandesites the 2 680 2 750 myr old1 5 intrusive granite greenstone terranes6 8 in the rainy lake region ontario and in and adjacent to the vermilion district minnesota of the superior province in north america include a wide variety of volcanic and intrusive rocks with initial pb sr and nd isotope ratios close to those for the mantle4 5 9 12 the isotopic constraints require the production of large volumes of silica oversaturated magmas from silica undersaturated mantle within 100 200 myr we present here geochemical data on monzodiorites and trachyandesites from the rainy lake area which are strongly enriched in large ion lithophile elements lile we conclude that they are derived by direct melting of the mantle at depths of 50km in either anhydrous or hydrous conditions their rare earth element ree abundances and initial 143nd 144nd ratios suggest that their mantle sources were enriched in lile shortly before melting the monzodiorites trachyandesites and their granodioritic derivatives may comprise up to 20 of the exposed igneous rocks in the rainy lake region and vermilion district if these rocks are as abundant in other archaean terranes a significant part of the early continental crust could have formed by direct melting of lile enriched mantle

esmeralda bank geochemistry of an active submarine volcano in the mariana island arc esmeralda bank is the southernmost active volcano in the izu volcano mariana arc this submarine volcano is one of the most active vents in the western pacific it has a total volume of about 27 km3 rising to within 30 m of sea level two dredge hauls from esmeralda recovered fresh nearly aphyric vesicular basalts and basaltic andesites and minor basaltic vitrophyre these samples reflect uniform yet unusual major and trace element chemistries mean abundances of tio2 1 3 and feo 12 6 are higher and cao 9 2 and al2o3 15 1 are lower than rocks of similar silica content from other active mariana arc volcanoes mean incompatible element ratios k rb 488 and k ba 29 of esmeralda rocks are indistinguishable from those of other mariana arc volcanoes on a ti zr plot esmeralda samples plot in the field of oceanic basalts while other mariana arc volcanic rocks plot in the field for island arcs

geomorphology of coal seam fires abstract coal fires occur in underground natural coal seams in exposed surface seams and in coal storage or waste piles the fires ignite through spontaneous combustion or natural or anthropogenic causes they are reported from china india usa south africa australia and russia as well as many other countries coal fires lead to loss of a valuable resource coal the emission of greenhouse relevant and toxic gases and vegetation deterioration a dangerous aspect of the fires is the threat to local mines industries and settlements through the volume loss underground surface collapse in coal fire areas is common thus coal fires are significantly affecting the evolution of the landscape based on more than a decade of experience with in situ mapping of coal fire areas worldwide a general classification system for coal fires is presented furthermore coal seam fire geomorphology is explained in detail the major landforms associated with and induced by these fires are presented the landforms include manifestations resulting from bedrock surface fracturing such as fissures cracks funnels vents and sponges further manifestations resulting from surface bedrock subsidence include sinkholes trenches depressions partial surface subsidence large surface subsidence and slides additional geomorphologic coal fire manifestations include exposed ash layers pyrometamorphic rocks and fumarolic minerals the origin evolution and possible future development of these features are explained and examples from in situ surveys as well as from high resolution satellite data analyses are presented the geomorphology of coal fires has not been presented in a systematic manner knowledge of coal fire geomorphology enables the detection of underground coal fires based on distinct surface manifestations furthermore it allows judgments about the safety of coal fire affected terrain additionally geomorphologic features are indicators of the burning stage of fires finally coal fire geomorphology helps to explain landscape features whose occurrence would otherwise not be understood although coal fire induced thermal anomalies and gas release are also indications of coal fire activity as addressed by many investigators no assessment is complete without sound geomorphologic mapping of the fire induced geomorphologic features

melting experiments on a high magnesian andesite abstract melting experiments were conducted on a high magnesian bronzite olivine andesite teraga ike andesite which is considered to be a primary andesite the high magnesian andesite magma is in equilibrium with both olivine and orthopyroxene at about 15 5 kbar and 1080 c under h2o saturated conditions and at lower pressure and higher temperature under h2o undersaturated conditions this suggests that high magnesian andesites could be generated by the partial melting of upper mantle peridotite containing a small amount of h2o

shear wave velocity based probabilistic and deterministic assessment of seismic soil liquefaction potential abstractshear wave velocity vs offers a means to determine the seismic resistance of soil to liquefaction by a fundamental soil property this paper presents the results of an 11 year international project to gather new vs site data and develop probabilistic correlations for seismic soil liquefaction occurrence toward that objective shear wave velocity test sites were identified and measurements made for 301 new liquefaction field case histories in china japan taiwan greece and the united states over a decade the majority of these new case histories reoccupy those previously investigated by penetration testing these new data are combined with previously published case histories to build a global catalog of 422 case histories of vs liquefaction performance bayesian regression and structural reliability methods facilitate a probabilistic treatment of the vs catalog for performance based engineering applications where possible uncertainties of the variables comprising both the seismic demand an

nd and sr isotopic variations in acidic rocks formed under a peculiar tectonic environment in miocene southwest japan initial nd and sr isotopic ratios were obtained for middle miocene igneous rocks as well as for related rocks from the outer zone of southwest japan to investigate the petrogenesis of acidic magmas and their relation to a peculiar tectonic environment bearing on the back arc spreading of the japan sea on the nd sr diagram data points for the acidic rocks fall in the nd sr quadrant occupying different positions from those for sedimentary and old crustal rocks and seem to define several subparallel lines which extend towards the lower righthand sedimentary field the s type acidic rocks occupy an intermediate position between i type rocks and sedimentary ones a fact suggesting mixing of an igneous component and a sedimentary one the linear mixing trend observed on the nd sr diagram can be attained in the restricted case that the igneous component has similar sr nd concentration ratios to that of the sedimentary one which implies an intermediate to acidic composition for the igneous component inconsistency between the elemental and isotopic variations observed may be reconciled by considering that mixing probably in the relatively deep part of the crust might have occured prior to chemical differentiation processes the episodic igneous activity and the high heat energy required to melt such materials involving sedimentary rocks may be explained by a model in which a hot mantle region probably corresponding to the rising part of the mantle convection supplied the heating energy to the outer zone of southwest japan when passing beneath southwest japan in the course of movement of the hot rising part from the shikoku basin areas to the japan sea area

correlation between liquefaction resistance and shear wave velocity of granular soils a micromechanical perspective the shear wave velocity method has become an increasingly popular means to evaluate the liquefaction potential of granular soils understanding the fundamental mechanism underlying existing empiric

correcting liquefaction resistance of unsaturated soil using wave velocity abstractexplicit empirical relationships for correcting liquefaction resistance of unsaturated soil below the groundwater table using compression wave velocity vp and shear wave velocity vs are derived and evaluated in this paper the relationships are derived using published laboratory test data for four different sands and one silt material the laboratory test data based on vp exhibit less scatter than the test data based on the ratio vp vs for this reason the vp based relationship is recommended for correcting the liquefaction resistance of unsaturated soil the influence of loading cycles and relative density on the recommended relationship is investigated from a review of 40 field case history sites it is found that in the critical layers at 20 of the sites average vp is less than 1 400 m s indicating unsaturated conditions liquefaction resistances computed for eight field case histories with vp 1 200 m s in the critical layers are corrected and plotted on penetration and vs based lique

geochemical provenance of sediments from the northern east china sea document a gradual migration of the asian monsoon belt over the past 400 000 years abstract the reconstruction of the long term evolution of the east asian monsoon remains controversial in this study we aim to give a new outlook on this evolution by studying a 400 kyr long sediment record u1429 from the northern east china sea recovered during iodp expedition 346 neodymium isotopic ratios and rare earth element concentrations of different grain size fractions reveal significant provenance changes of the sediments in the east china sea between east asian continental sources mainly yellow river and sediment contributions from the japanese archipelago these provenance changes are interpreted as the direct impact of sea level changes due to the reorganization of east asian river mouth locations and ocean circulation on the east china sea shelf and latitudinal shifts of the intertropical convergence zone itcz from the interior of asia to the western north pacific ocean our data reveal the dominance of winter and summer monsoons during glacial and interglacial periods respectively except for glacial mis 6d 150 180 ka during which unexpected summer monsoon dominated conditions prevailed finally our data suggests a possible strengthening of the interglacial summer monsoon rainfalls over the east asian continent and japan throughout the past 400 kyr and between mis 11 and mis 5 in particular this could result from a gradual northward migration of the itcz

origin of the granodiorite in the forearc region of southwest japan melting of the shimanto accretionary prism abstract in the forearc region of southwest japan felsic to intermediate volcano plutonic complexes of middle miocene age intruded into the shimanto accretionary complex possibly in association with megatectonic events such as the opening of the japan sea and resultant underthrusting of the newly borne shikoku basin philippine sea plate beneath the southwest japan arc activities of mantle derived magmas are also distinct in the forearc of middle miocene southwest japan tholeftic basalts are closely related to igneous activity of the shikoku basin and high mg andesites probably formed under anomalously high temperature conditions caused by the opening of japan sea two plutons uwajima and miuchi were chosen for understanding the origin of felsic magmas in the forearc region of southwest japan all granitic rocks of the plutons show enriched isotopic characteristics with higher 87 sr 86 sr and lower 143 nd 144 nd tha bulk earth which suggests that the contribution of crustal materials has a magma source however they have lower 87 sr 86 sr and higher 143 nd 144 nd than shimanto sediments and hence an additional component with lower 87 sr 86 sr and higher 143 nd 144 nd than granitic rocks must be required possible candidates for such components are coeval mantle derived magmas mass balance modelling between mantle derived magmas and shimanto sediments on the basis of their sr nd isotopic compositions suggested that mixing of anatectic melt of the shimanto sediments and porphyritic andesite magma evolved from high mg andesite as a possible mechanism of the origin of the granodiorites of the uwajima pluton injection of high mg andesite into the shimanto accretionary prism may triggered the melting of sediments calculated composition of anatectic melt of the shimanto sediment and p t condition of the gneissose enclave in the granodiorite suggest that the melting of sediments may have occurred at higher temperature conditions than those of the melting reactions involving biotite breakdown