hydrothermal alteration and fluid chemistry of the endako porphyry molybdenum deposit british columbia hydrothermal alteration and fluid chemistry data of the early cretaceous endako porphyry molybdenum deposit british columbia provide new information on the hydrothermal fluids associated with low fluorine molybdenite mineralization molybdenite mineralization and hydrothermal alteration occur as early quartz molydenite stockwork veins with k feldspar bearing selvages and paragenetically later quartz molybdenite ribbon veins with sericite bearing selvages late hydrothermal alteration is associated with the development of kaolinite and postore tertiary age calcite veins fluid inclusions in early formed quartz molybdenite stockwork veins with k feldspar bearing alteration assemblages are dominated by moderate salinity 5 to 15 wt nacl equiv liquid rich type 1 and rare high salinity 30 to 45 wt nacl equiv halite bearing type 3 fluid inclusions type 1 and type 3 fluid inclusions in early veins homogenize between 390 and 430 c and 375 and 420 c respectively secondary fluid inclusions type 2 of low salinity 1 to 5 wt nacl equiv in these early veins are minor and homogenize between 130 and 285 c fluid inclusions in quartz molybdenite ribbon veins with sericite bearing alteration assemblages are dominated by moderate salinity liquid rich type 1 inclusions with minor type 2 fluid inclusions type 1 fluid inclusions of ribbon veins homogenize between 360 and 400 c fluid inclusions in postore calcite veins are of only type 2 fluid inclusions which homogenize at 209 c hydrothermal fluids recorded by type 1 and type 3 fluid inclusions in early veins were trapped under lithostatic to hydrostatic conditions between 0 3 and less than or equal to 2 0 kbar and 360 and 560 c postore fluids recorded by type 2 fluid inclusions were trapped under conditions less than or equal to 0 5 kbar and between 190 and 300 c quartz stockwork and ribbon veins possess 18o values of 8 4 0 2 n 9 and 8 4 0 6 n 13 respectively hydrothermal k feldspar and biotite from k feldspar alteration assemblages possess 18o values of 6 8 0 4 n 7 and 3 5 0 8 n 8 respectively oxygen isotope geothermometry of quartz biotite and quartz k feldspar pairs from k feldspar alteration assemblages yield temperatures between 200 and 490 c which is similar to the trapping temperatures of hydrothermal fluids determined from fluid inclusion studies associated with molybdenite mineralization the development of kaolinite and calcite veins the oxygen isotope temperatures of the quartz biotite and quartz k feldspar pairs suggest that k feldspar and biotite either record the approximate 18o composition of hydrothermal fluids associated with k feldspar alteration or have undergone 18o exchange with late stage hydrothermal fluids hydrogen isotope composition of quartz stockwork and ribbon veins fluid inclusion waters range between 105 and 173 per mil solute chemistry studies of fluid inclusion waters indicate that ore forming fluids from endako have low br cl and br na ratios and high i cl and i br ratios in comparison to porgera epithermal babine lake porphyry cu and st austell capitan pluton vein deposits associated with magmatic processes na k ratios of fluid inclusion waters yield temperatures 308 to 429 c similar to those determined from type 1 and type 3 fluid inclusions and stable isotope thermometry results from fluid inclusion and solute chemistry studies indicate the involvement of hydrothermal fluids exsolved from a crystallizing melt in the formation of the endako molybdenum deposit however oxygen and hydrogen isotope values deviate from the generally accepted magmatic compositions which suggests the early involvement of meteoric water in the ore forming fluids and ore genesis

metallogeny of the handagai skarn fe cu deposit northern great xing an range ne china constraints on fluid inclusions and skarn genesis abstract the newly discovered handagai skarn fe cu deposit is located in the northern great xing an range of ne china and is hosted by the ordovician luohe formation the orebodies that form the deposit are generally concordant with the bedding within these sediments and are spatially related to areas of skarn development the fe cu mineralization in this area records four stages of paragenesis namely prograde skarn retrograde skarn quartz sulfide and quartz carbonate stages the handagai deposit is a calcic skarn that is dominated by an andradite diopside epidote actinolite assemblage the mineralogy and geochemistry of the skarn indicate that it formed from a hydrothermal fluid that altered the carbonate units in this area to a garnet and42 95grs4 53 and pyroxene di71 78hd22 29jo0 2 bearing skarn the epidote within the skarn has an epidote end member composition with the chlorite in the skarn dominantly fe rich indicating that these minerals formed in an fe rich environment the petrographic microthermometric and raman spectroscopic analysis of fluid inclusions within garnet epidote actinolite quartz and calcite precipitated at different stages of formation of the handagai deposit indicate that mineralization related fluid inclusions are either liquid rich two phase h2o nacl type i gas rich two phase h2o nacl type ii three phase liquid vapor solid h2o nacl type iii or co2 h2o nacl inclusions type iv the early stages of mineralization are associated with all four types of inclusion whereas the later stages of mineralization are only associated with type i and ii inclusions inclusion homogenization temperatures vary between the four stages of mineralization 370 c 530 c and 600 c 210 c 290 c 190 c 270 c and 150 c 230 c from early to late respectively with salinities also varying between the earlier and later stages of mineralization 11 18 and 45 7 15 6 9 and 3 7 wt nacl equivalent equiv respectively the majority of the inclusions within the handagai deposit have homogenization temperatures and salinities of 200 c 350 c and 4 14 wt nacl equiv respectively indicating that this is a medium high temperature and medium low salinity type deposit the fluid inclusions were trapped at pressures of 11 to 72 mpa corresponding to depths of 0 4 to 2 9 km the geology mineralogy geochemistry and fluid inclusions microthermometry indicate that the handagai deposit formed as a result of contact infiltration metasomatism with the deposition of ore minerals resulting from a combination of factors that include boiling as a result of reduced pressure cooling and fluid mixing

the evolution of tungsten sources in crustal mineralization from archean to tertiary inferred from lead isotopes lead isotope compositions of 31 tungsten bearing mineral occurrences worldwide with ages ranging be tween archean and tertiary have been determined to assess the evolution of tungsten sources in crustal min eralization through time the data indicate that tungsten of crustal mineralization was mainly supplied by the mantle between 3 0 and 2 4 ga the possibility of increasing contributions from the newly formed crust to tungsten mineralization throughout the archean is suggested by the available data although this suggestion needs to be tested by additional measurements the tungsten occurrences of proterozoic age contain mature crustal lead reflecting their association with crustal reworking through metamorphism and magmatism in the proterozoic mobile belts from 0 5 ga onward tungsten mineralization displays a renewed mantle lead con tribution owing to the direct or indirect association of post 0 5 ga tungsten occurrences with subduction re lated magmatic rocks of the phanerozoic orogenic cycles the data presented also suggest that several tungsten mineralization pulses may have recycled tungsten from older reservoirs

quantifying measurement uncertainty of thirty meter shear wave velocity thirty meter shear wave velocity v s 30 is commonly used to estimate near surface conditions for site classification seismic site response liquefaction analysis and other geotechnical earthquake engineering application quantifying the uncertainty in v s 30 measurements is important for determining the accuracy and precision of this geophysical test this study gathers existing available comparative and blind shear wave velocity tests to evaluate the apparent or observable intra and intermethod variability presented in this article are estimates of v s 30 uncertainty for the invasive methods of downhole suspension logging and seismic cone penetration testing the noninvasive method of spectral analysis of surface waves and the method of shear wave velocity correlated geologic units discussed is the issue of soil disturbance with respect to invasive methods and how this may result in measurement bias results of this study indicate that uncertainty of shear wave velocity measurements are on the order of 1 3 coefficient of variation standard deviation mean for downhole suspension logging and seismic cone penetration testing 5 6 coefficient of variation for spectral analysis of surface waves and 20 35 coefficient of variation for shear wave velocity correlated geologic units presented here are procedures for propagating the uncertainty and or bias in forward analyses

fluid chemistry structural setting and emplacement history of the rosario cu mo porphyry and cu ag au epithermal veins collahuasi district northern chile the rosario cu mo ag deposit is located in the collahuasi district of northern chile it comprises high grade cu ag au epithermal veins superimposed on the core of a porphyry cu mo orebody rosario has mining reserves of 1 094 million metric tons mt at 1 03 percent copper an additional 1 022 mt at 0 93 percent copper occurs in the district at the nearby ujina and quebrada blanca porphyry deposits the rosario reserve contains over 95 percent hypogene ore whereas supergene sulfide ores dominate at ujina and quebrada blanca mineralized veins are hosted within lower permian volcanic and sedimentary rocks lower triassic granodiorite and late eocene porphyritic quartz monzonite the rosario fault system a series of moderate southwest dipping faults has localized high grade cu ag au veins at cerro la grande similar high grade cu ag au veins are hosted in north northeast trending sinistral wrench faults normal movement in the rosario fault system is interpreted to have been synchronous with sinistral strike slip deformation at la grande hydrothermal alteration at rosario is characterized by a k feldspar core focused in the rosario porphyry that grades out to a secondary biotite albite magnetite assemblage paragenetic relationships indicate that magnetite was the earliest formed alteration product but has been replaced by biotite albite vein crosscutting relationships indicate that k feldspar formed during and after biotite albite alteration chalcopyrite and bornite were deposited in quartz veins associated with both k feldspar and biotite albite assemblages the early hydrothermal fluid was a hypersaline brine 40 45 wt nacl that coexisted with vapor between 400 degrees and 600 degrees c weakly mineralized illite chlorite intermediate argillic alteration of the early k and na silicate assemblages was caused by moderate temperature 250 degrees 350 degrees c moderate salinity brines 10 15 wt nacl molybdenite was precipitated in quartz veins that formed between the potassic and intermediate argillic alteration events these fluids were 350 degrees to 400 degrees c with salinities between 10 and 15 wt percent nacl porphyry style ore and alteration minerals were overprinted by structurally controlled quartz alunite pyrite pyrophyllite dickite and muscovite quartz phyllic alteration assemblages the quartz alunite pyrite alteration formed at 300 degrees to 400 degrees c from fluids with a salinity of 10 wt percent nacl the pyrophyllite dickite assemblage formed between 250 degrees and 320 degrees c from dilute 5 wt nacl fluids an upward flared zone of muscovite quartz pyrite altered rocks surrounds the fault controlled domain of advanced argillic alteration thick veins 0 5 2 m wide of fault hosted massive pyrite chalcopyrite and bornite precipitated brines with a salinity of 30 wt percent nacl at temperatures of 250 degrees to 300 degrees c pressure depth estimates indicate that at least 1 km of rock was eroded at rosario between formation of the k na silicate and advanced argillic assemblages this erosion was rapid occurring over a period of 1 8 m y the rosario porphyry intruded immediately after the incaic tectonic phase implying that it was emplaced as the domeyko cordillera underwent gravitational collapse expressed as normal faults in the upper crust gravitational sliding potentially accelerated exhumation and helped to promote telescoping of the high sulfidation environment onto the rosario porphyry the hydrothermal system responsible for porphyry cu mineralization at rosario was partially exhumed prior to the formation of high sulfidation ore and alteration assemblages this implies that emplacement of a second blind intrusion occurred somewhere beneath the rosario and cerro la grande high sulfidation vein systems and is supported by the fault geometry and zoning of precious metals and sulfosalts at the district scale

the role of magmatic sulfides and mafic alkaline magmas in the bingham and tintic mining districts utah this paper reports the existence of abundant magmatic sulfides in introduction latite lava vitrophyres and vent facies dikes from the bingham and the eruption of sulfur rich magmas from el chichon tintic districts in central utah these dikes and flows appear to luhr et al 1984 and mt pinatubo westrich gerlach be comagmatic with the ore related monzonite intrusions in addition 1992 in recent years has attracted attention to the limited analytical data suggest that the magmatic sulfides contain most of solubility of sulfur in intermediate magmas and the factors the cu and ag present in the latites magmatic sulfides are preserved potentially responsible for the formation of magmatic only in the least oxidized and least degassed lavas and vitrophyres sulfides and anhydrite however the occurrence of magpetrography of comagmatic dikes and intrusions suggests that matic sulfides in intermediate magmas is not universal resorption and oxidation s degassing of the globules may make many volcanic suites appear to be sulfide unsaturated the metal content available to a magmatic ore fluid minette and inasmuch as magmatic sulfides may sequester chalcophile shoshonite lavas occur in subordinate amounts in the latitic volcanic metals what would their presence signify in magmatic fields associated with latite monzonite intrusions and hydrothermal systems that formed porphyry cu and mesothermal vein ore deposits of the tintic ag pb zn cu au and bingham deposits do they sequester a significant portion of the porphyry cu au mo districts utah the ages chemical and magmatic cu pb zn ag and au thereby restricting modal compositions and field relations of the mafic alkaline lavas metal availability of subsequent ore forming fluids suggest that such magmas mixed and fractionated at shallow crustal we have examined the volcanic rocks from the tintic levels to form the ore related latites and monzonites the unaltered and bingham mining districts fig 1 utah and found mafic alkaline lavas in these districts are some of the most cu rich that almost all of the volcanic units contain magmatic lavas in the great basin province sulfides some quenched dikes and intrusion margins also have preserved magmatic sulfides comparable with those in the volcanic rocks several lines of evidence indicate that the volcanic and intrusive rocks are comagmatic keith et al 1989 1991 waite 1996 the tintic district and east tintic sub district in utah have recorded over

episodic fluid evolution in the formation of the large scale luoyang fe deposit fujian eastern china abstract the luoyang fe skarn deposit is located in the yong an meizhou depression belt in fujian province eastern china skarn alteration and mineralization are concentrated in a zone adjacent to an early yanshanian granite porphyry 146 ma within limestone of the upper carboniferous chuanshan and lower permian qixia formations petrographic observations reveal five paragenetic stages of skarn formation and ore deposition stage 1 early skarn andradite stage 2 diopside magnetite stage 3 late skarn actinolite chlorite tremolite magnetite pyrite stage 4 quartz calcite fluorite pyrite hematite sphalerite galena chalcopyrite and stage 5 calcite quartz we analyzed fluid inclusions in garnet diopside calcite and quartz from stages 1 2 4 and 5 and measured h o isotopic compositions of fluid inclusions in garnet magnetite and quartz from stages 1 2 and 4 observations of fluid compositions and phase assemblages allow three types and two subtypes of fluid inclusions to be distinguished halite bearing type 1a and hematite bearing type 1b vapor rich type 2 and liquid rich aqueous inclusions type 3 in stage 1 garnet contains type 1a 1b and 2 primary fluid inclusions which comprise two immiscible phases that formed through boiling in stage 2 diopside contains type 1a and 2 fluid inclusions that also record boiling which resulted in the precipitation of magnetite in stage 4 quartz contains type 3 primary inclusions that are related to sulfide mineralization in stage 5 calcite and quartz contain type 3 fluid inclusions which represent the post sulfide mineralization fluids microthermometric and h o isotopic data indicate that multiple episodes of fluid flow occurred in the luoyang deposit during the early skarn stage an initial supercritical fluid that exsolved during crystallization of the parent granitic magma ascended and underwent a first boiling event at 488 c 536 c and 380 438 bar lithostatic pressure which produced two fluids with differing salinities represented by type 1a and 2 inclusions this stage of boiling resulted in minor magnetite precipitation and type 1b fluid inclusions associated with this stage contain hematite the magnetite stage was associated with a second episode of fluid ascent as the parent magma cooled to 454 c 498 c which triggered a second boiling event and abundant magnetite precipitation at 336 449 bar lithostatic pressure the sulfide stage is associated to a third period of fluid ascent and occurred at 220 c 261 c at the same pressure conditions as the second boiling event 380 bar this stage included the input of meteoric water which resulted in sulfide precipitation late stage carbonate crystallization involved the influx of further meteoric water at lower temperatures 144 c 193 c and the same pressure 380 bar representing the collapse of the skarn system these observations suggest that the luoyang deposit formed at a shallower depth than the makeng deposit which is located within the same belt variations in skarn alteration and magnetite mineralization are ascribed to the difference in depth between the two skarn systems

direct evolution of w rich brines from crystallizing melt within the mariktikan granite pluton west transbaikalia uneconomic tungsten mineralization associated with the mariktikan granite pluton of the transbaikalian igneous province eastern siberia is confined to a marginal part of the pluton referred to as the andreyevsky body this is composed of rocks similar to those of the main pluton but is likely to be an autonomous although kindred body on the basis of cross cutting relationships between rock varieties and their textural features the crystallization history is subdivided into three stages of unequal duration melt and fluid inclusions related to each of them have been studied using microthermometric and micro analytical procedures including a technique for atomic emission spectroscopy of individual fluid inclusions opened by a laser microprobe during the main crystallization stage 1045 1012 c more than 70 of the parental magma is believed to have crystallized at the level studied resulting in the formation of a crystalline framework rigid enough for the appearance of fractures within which some portion of the intercrystalline melt accumulated giving rise to thin aplite veins almost complete crystallization of intercrystalline and fracture hosted melt occurred during the late stage 1012 990 c whereas during the final stage only small bunches of schlieric sometimes miarolitic pegmatite were formed from a few pockets of residual melt 990 917 c in spite of the low water content of the melt about 1 wt fluid separation took place from the onset of crystallization during the main crystallization stage the exsolved fluid divided into two immiscible phases co2 rich gas and salt rich liquid brine however it was homogeneous thereafter major ore components of the brine mn fe w displayed different behaviour as crystallization progressed w concentration was below 0 1 wt at the main stage attained 1 wt during the late stage and increased to 1 8 wt at the final stage comparison of these data with calculations carried out using estimated parameters for the parental magma enables us to infer that obtained concentration values are reasonable for the special case studied here however they are unlikely to be attainable if the magma is h2o enriched and lacks an anomalously high w content in the andreyevsky body of the mariktikan pluton the following features of the parental magma made possible the generation of w rich solutions 1 high liquidus temperature 1045 c and elevated cl content c 0 15 wt that resulted in enlargement of the fluid melt distribution coefficient c 10 2 low water content c 1 and elevated w content c 0 001 wt that provided a relatively high w h2o ratio within the system at the same time because of the low water content of the magma the total mass of w bearing solutions has proved to be insufficient for the production of large scale mineralization a reduced w content of the great bulk of the exsolved brine may have had an unfavourable effect as well

evolution of the mo rich scheelite skarn mineralization at kozbudaklar western anatolia turkey evidence from mineral chemistry and fluid inclusions abstract the kozbudaklar scheelite skarn deposit in the tavsanli zone located approximately 22 km southeast of bursa is hosted by the triassic calcic inonu marble and eocene topuk pluton at least four stages have been recognized through skarn evolution scheelite skarn distributed close to the topuk pluton occurred during the early stage 1 and late stage 2 prograde substages the early prograde endo and exoskarn are composed of hedenbergite hd 96 joh 4 plagioclase an 55 64 and hedenbergite hd 61 94 joh 4 7 accompanied by calcic garnet grs 38 94 sps 1 5 alm 0 and scheelite pow 1 6 the second stage represents a relatively oxidized mineralogy dominated by diopside hd 16 48 joh 0 9 subcalcic garnet grs 24 92 sps 0 11 alm 0 31 and scheelite pow 7 32 the stage 3 and 4 mineral assemblages are characterized by few hydrous minerals in the retrograde stage and intense fracturing fluid inclusions from skarn rocks are indicative of multiple fluid events 1 low moderate salinity 5 16 wt nacl equiv inclusions homogenized dominantly by a high temperature 308 c to 600 c liquid phase in stage 1 fluid inclusions in an early garnet homogenized over a similar temperature range 440 c and 459 c into both liquid and vapor phases eutectic temperatures ranging from 61 7 c to 35 0 c that indicate the presence of h 2 o nacl mgcl 2 cacl 2 co 2 solutions 2 coexisting daughter mineral bearing high salinity 29 5 70 wt nacl equiv and vapor rich moderate salinity 11 5 16 7 wt nacl equiv inclusions that homogenized in the liquid phase by the disappearance of the vapor phase at a similar temperature range 308 c to 600 c in stage 2 eutectic temperatures range from 67 9 c to 51 8 c that shows the presence of h 2 o nacl co 2 ch 4 n 2 solutions 3 low moderate salinity 12 5 7 6 wt nacl equiv and temperature 320 c to 215 c inclusions homogenized by the liquid phase in stage 3 eutectic temperatures range from 59 5 c to 44 2 c indicating the presence of h 2 o nacl mgcl 2 cacl 2 co 2 solutions 4 inclusions of low salinity 9 9 0 9 wt nacl equiv and homogenization temperature 183 c to 101 c in stage 4 these data show that the kozbudaklar skarn deposit was formed in a magmatic hydrothermal system in this model carbonaceous fluids may have been exsolved from the plutonic rock during its emplacement and crystallization fluid inclusion data indicate that fluid boiling and immiscibility occurred at temperatures between 440 c and 459 c and pressures ranging from 50 mpa to 60 mpa based on hydrostatic considerations early scheelite was precipitated with relatively reduced mineral compositions as a result of depressurization mo rich scheelite with oxidized minerals formed via high salinity and vapor rich inclusions the second scheelite mineralization occurred in a normal hydrothermal system by an infiltration mechanism at pressures between approximately 40 and 1 5 mpa at shallow depths

a terrain based site conditions map of california with implications for the contiguous united states abstract we present an approach based on geomorphometry to predict material properties and characterize site conditions using the v s 30 parameter time averaged shear wave velocity to a depth of 30 m our framework consists of an automated terrain classification scheme based on taxonomic criteria slope gradient local convexity and surface texture that systematically identifies 16 terrain types from 1 km spatial resolution 30 arcsec shuttle radar topography mission digital elevation models srtmdems using 853 v s 30 values from california we apply a simulation based statistical method to determine the mean v s 30 for each terrain type in california we then compare the v s 30 values with models based on individual proxies such as mapped surface geology and topographic slope and show that our systematic terrain based approach consistently performs better than semiempirical estimates based on individual proxies to further evaluate our model we apply our california based estimates to terrains of the contiguous united states comparisons of our estimates with 325 v s 30 measurements outside of california as well as estimates based on the topographic slope model indicate our method to be statistically robust and more accurate our approach thus provides an objective and robust method for extending estimates of v s 30 for regions where in situ measurements are sparse or not readily available

mineralogical and metasomatic evolution of the jurassic baoshan scheelite skarn deposit nanling south china abstract the baoshan scheelite deposit located in the nanling region south china is a skarn type tungsten ore deposit orebodies occur in the contact zone between carboniferous limestone and baoshan granitic pluton the pluton consists mostly of coarse grained porphyritic and fine grained biotite granites which have zircon u pb ages of 172 4 0 3 ma 166 6 0 3 ma and 156 6 1 4 ma respectively these rocks have similar geochemical characteristics with high sio2 total alkalis high differentiation indexes and high rb sr ratios of s type granites formed by partial melting of upper continental crust the porphyritic granites display the highest degree of fractionation and are most closely associated with the formation of skarn ores the skarns are zoned mineralogically outward from garnet through clinopyroxene to wollastonite and overprinted by retrograde minerals three stages of skarnization are recognized early prograde late prograde and retrograde the early prograde stage is mainly composed of al rich garnet grs60 76 and mg rich clinopyroxene di41 62 with subordinate mo rich scheelite sch59 86 all of which are typically overgrown by late prograde assemblages of fe rich garnet and67 95 fe rich clinopyroxene hd81 87 and mo depleted scheelite sch97 98 the retrograde stage is characterized by al rich garnet grs40 66 and pure scheelite sch100 accompanied by hydrous and sulfide minerals minor subcalcic garnet with magnetite sometimes occurs in the limited endoskarns fluid inclusions of the early prograde minerals homogenize at 390 5 to 550 c and one inclusion in wollastonite has a salinity of 13 0 equiv wt nacl inclusions in minerals of the late prograde and retrograde stages have homogenization temperatures of 196 9 377 4 c and 160 4 291 4 c respectively their salinities 2 4 19 0 equiv wt nacl and 1 4 11 6 equiv wt nacl respectively accordingly the high temperature and moderate to high salinity fluids in the early skarn stages are typical of magmatic fluids originating granites whereas the lower temperature and variable salinity in the later stages suggest mixing with meteoric water

geology chronology fluid inclusions and h o s isotopic compositions of the hongyuntan magnetite deposit eastern tianshan nw china abstract the hongyuntan magnetite deposit which is located in the aqishan yamansu belt of eastern tianshan xinjiang is hosted within carboniferous submarine volcanic sedimentary sequences the deposit is characterized by five metallogenic stages stage i garnet diopside stage ii magnetite tremolite chlorite pyrite stage iii magnetite quartz albite actinolite stage iv pyrite quartz epidote and stage v hematite limonite pyrite associated with magnetite formed during the stage ii has a re os isochron age of 324 31 ma four types of fluid inclusions were observed in the mineral assemblages namely two phase liquid and vapor inclusions multi phase daughter mineral bearing inclusions multi phase co2 bearing inclusions and monophase vapor inclusions microthermometry data reveal that the ore forming fluids evolved from high temperature average 532 5 c and high salinity average 26 9 wt nacleqv fluids to moderate low temperature average 203 6 c and low salinity 5 07 wt nacleqv fluids magnetite precipitation may have been greatly assisted by mixing and boiling in stage ii and stage iii respectively the hydrogen and oxygen isotopic values of stage i garnet dv smow 107 9 to 76 7 18ofluid 6 4 10 7 and stage iii quartz dv smow 85 5 to 83 2 18ofluid 3 8 4 7 indicate that the ore forming fluids were dominated by magmatic water whereas fluid mixing occurred during stage ii dv smow 117 3 to 112 6 18ofluid 3 3 5 7 and stage iv dv smow 115 2 to 58 5 18ofluid 1 3 to 4 5 the variable 34s values of pyrite 3 8 to 4 7 and 18omgt values of magnetite 0 6 to 4 1 suggest that they were not sourced from a single reservoir the hongyuntan magnetite deposit is spatially and temporally associated with volcanism and may be genetically related to it the fluid inclusions and isotopic compositions of this deposit indicate that its ore forming fluid was derived from the exsolution of deep seated magmas and that fluid mixing could have effectively triggered the deposition of ore forming materials multiple periods of volcanic activity could have incorporated additional heat and ore metals into the ore forming system based on our data we conclude that the origin of the hongyuntan magnetite deposit is related to the volcanism in the carboniferous period

genesis and evolution of the leimengou porphyry mo deposit in west henan province east qinling dabie belt china constraints from hydrothermal alteration fluid inclusions and stable isotope data abstract the leimengou mo deposit is located in the east qinling dabie metallogenic mo belt located at the southern margin of the north china craton the deposit is hosted within the mesozoic leimengou granite porphyry pluton and at the contact between the granite and late archean gneisses in light of mineral assemblage and crosscutting relationships among veinlets the mineralization and alteration can be classified in four distinct stages 1 a mo barren pre mineralization stage of alteration characterized by massive k feldspar alteration of the granite porphyry 2 a k feldspar quartz vein stage that formed veinlets with minor molybdenite 3 a quartz sulfide veinlet stage which is the main stage of mineralization and 4 post mineralization quartz calcite vein stage stage 1 alteration is associated with fluid inclusions of low medium salinity 2 4 13 1 wt naclequiv that homogenized at medium to high temperatures 238 476 c stage 2 mineralization is associated with fluid inclusions that homogenized at 201 389 c and that have salinities of 2 0 13 6 wt naclequiv fluid inclusions that formed during stage 3 have homogenization temperatures of 205 370 c and corresponding salinities of 1 0 17 6 wt naclequiv to 31 4 40 6 wt naclequiv indicative of fluid immiscibility and mixing of hydrothermal fluids with meteoric water stage 4 h2o nacl fluids were trapped at lower temperatures 148 246 c and have salinities of 1 7 7 9 wt naclequiv stages 1 to 4 have calculated 18ofluid values of 3 6 4 3 2 7 2 8 0 6 2 3 and 3 2 to 3 8 respectively with dfluid values of 72 to 80 83 to 90 68 to 82 and 81 to 90 respectively these results are consistent with the fluid inclusion data outlined above and suggest that early fluids were exsolved from the granitic magma and underwent progressive mixing with meteoric water molybdenum was initially transported from the crystallizing magma in a hot alkaline and oxidized fluid while decreasing temperatures and ph water rock interaction and fluid immiscibility during fluid ascent resulted in its precipitation and deposition

geology mineralization and fluid inclusion characteristics of the koitash redox intermediate w mo skarn and w au stockwork deposit western uzbekistan tien shan the koitash w mo skarn deposit in the tien shan gold belt contained resources of 60 kt wo3 in altered skarn averaging 0 56 wo3 and 0 029 mo and an additional 42 kt wo3 in separate zones of phyllic alteration averaging 0 30 wo3 0 97 g t au 0 67 cu and 0 02 bi it is related to an early permian multiphase granodiorite granite leucogranite pluton that is composed of medium to high k transitional metaluminous to peraluminous weakly oxidized weakly reduced ilmenite titanite series granitoids the pluton was emplaced in a tectonic domain with inferred ancient continental crust the latter coupled with possible ascent of hot asthenospheric material has likely defined a distinct w mo au metallogenic assemblage forming in a post collisional environment the deposit includes redox intermediate prograde and retrograde pyroxene garnet skarns partially overprinted by propylitic and phyllic alteration assemblages comprising scheelite molybdenite cu bi ag te sulfides and sulfosalts as well as native bi and au compositional similarities between w mo deposits containing au w cu bi mineralization in late alteration assemblages and coeval intrusion related au dominant with minor w bi etc deposits in the region support their possible genetic links fluid inclusion data indicate the involvement of carbonic free moderately saline 10 5 15 0 to 8 0 11 7 wt nacl eq high pressure 2000 to 1500 bars hot 550 600 c aqueous fluid which was sourced from crystallizing magma and formed prograde calcic skarn this fluid was followed by moderately saline ca rich 14 16 wt nacl 19 21 wt cacl2 lower pressure 800 bars fluids toward the retrograde skarn stage with the deposition of scheelite in association with pyrrhotite and molybdenite locally with minor fluorite propylitic quartz amphibole chlorite oligoclase calcite with scheelite pyrrhotite locally molybdenite assemblages formed from boiling high methane aqueous carbonic fluids at temperatures of 370 400 c and pressures of 950 1000 bars phyllic quartz sericite fe carbonate locally with albite fluorite chlorite scheelite molybdenite and other sulfides also bi and au minerals alteration assemblages initially formed from homogeneous and then from boiling aqueous carbonic low salinity fluids at temperatures of 365 370 to 300 315 c and pressures of 2000 bars 34s increases from retrograde skarn 34s 2 0 to 2 3 through propylitic 34s 3 0 to 3 4 to phyllic alteration 34s 4 2 to 4 7 stages

influence of a sedimentary basin infilling description on the 2 d p sv wave propagation using linear and non linear constitutive models numerical modelling is a useful tool to understand the role of different parameters site geometry impedance contrast material properties constitutive model input motion governing site effects we focus here on the 2 d p sv seismic wave propagation in a simple shaped asymmetric model we consider two ways of describing the sedimentary infilling properties the basin is either composed of distinct homogeneous geological layers or is described through properties progressively changing as a function of depth smooth model in order to study the wave propagation in the two basins with similar soil properties p and s velocities of the layered basin are deduced from the smooth basin ones making both models compatible in a kinematic point of view p and s velocities globally increase with depth following epri non linear properties are considered as constant in layers for the two basins we assess the influence of the model choice on the wave propagation while taking into account linear and non linear constitutive models we test the influence of the input motion by propagating two different input motions the first being a simple impulsive one and the second a real complex accelerogram we find that transfer functions computed in each basin are quite similar irrespective of the soil constitutive behaviour and the input motion moreover we show that the maximum shear strain spatial distribution depends on the input motion frequency content and maximum values depend on the input motion strength and complexity maximum shear strains are generally higher for superficial layers than for deeper ones we show that the highest shear strain values are located above discontinuities where velocities are lower and the soil is more non linear than in the underlying layer regardless of the input motion indeed in a layered basin the shear strain is higher above interfaces for all the soil constitutive models that were used in the smooth visco elastoplastic model a kind of layering appears absent in a viscoelastic model due to the different non linear properties in each layer moreover no matter what the model structure and the input motion used maximum shear strain levels are higher in the visco elastoplastic soil than in the viscoelastic one such a numerical study helps to understand the non linearity location and therefore the consequences of a model choice when performing a site specific study

a bayesian approach for determining velocity and uncertainty estimates from seismic cone penetrometer testing or vertical seismic profiling data conventional processing methods for seismic cone penetrometer data present several shortcomings most notably the absence of a robust velocity model uncertainty estimate we propose a new seismic c

gold and metal enrichment in natural granitic melts during fractional crystallization metal evolution in a composite granitic pluton was tracked by analyzing melt inclusions in 11 quartz samples from 7 zones at the timbarra gold deposit australia we present the first quantitative microanalyses of gold au in granitic silicate melt inclusions using laser ablation inductively coupled plasma mass spectrometry and show how au and other metals become enriched during fractional crystallization in a granite intrusion au was enriched during fractionation from a monzogranite to a highly fractionated alkali feldspar granite similar enrichment behavior for other metals implies that no gold enriched precursor melt is required and fractional crystallization can enrich the au concentration to economic levels the low content of accessory oxides and sulfides the absence of early cl bearing fluids the volatile content in the melt and a prolonged crystallization constitute important factors for extensive metal enrichment during crystal fractionation these characteristics play a crucial role in felsic highly fractionated plutons and their associated deposits such as intrusion related au deposits the gold enrichment during fractionation also implies that au is directly sourced from the granites

geology mineralization and fluid inclusion characteristics of the chorukh dairon w mo cu skarn deposit in the middle tien shan northern tajikistan abstract the chorukh dairon deposit is part of the metallogenic belt of w mo cu mo au w and au deposits along the late paleozoic active continental margin of the tien shan it is related to the late carboniferous multiphase pluton with successive intrusive phases of early monzogabbro through monzonite quartz monzonite to monzogranite and leucogranite and the latest lamprophyre dikes the deposit is an example of complex w mo cu magmatic hydrothermal system related to magnetite series shoshonitic igneous suite it contains zones of w cu mo oxidized prograde and retrograde skarns with abundant scapolite plagioclase k feldspar andradite garnet magnetite as well as molybdoscheelite and minor chalcopyrite and molybdenite skarns are overprinted by hydrosilicate alteration assemblages with amphibole chlorite epidote quartz calcite scapolite albite scheelite and chalcopyrite and are cut by quartz carbonate barite fluorite sulfide veins the fluid evolution included a release of high temperature 400 500 c high pressure 900 1100 to 700 800 bars high salinity magmatic hydrothermal aqueous chloride fluid with its direct separation from crystallizing magma and formation of prograde and retrograde skarns fluid enrichment in ca up to 15 22 wt cacl 2 at the retrograde skarn stage was possibly related to magmatic differentiation and provided intense molybdoscheelite deposition from a homogenous fluid in contrast hydrosilicate alteration assemblages were formed at lower temperatures 350 400 c initially from a homogenous and then from a boiling ca rich 20 22 wt cacl 2 magmatic hydrothermal fluid with the latter contributing to the most intense scheelite deposition the stable isotope data 13 c co 2 3 0 0 5 and 18 h 2 o 6 5 0 5 34 s 7 5 to 7 7 obtained for the hydrosilicate stage minerals suggest significant fluid sourcing from magmatic and meteoric waters as well as from sedimentary rocks enriched in seawater sulfate possibly evaporites although a strongly homogenous character of the isotopic composition reveals intense isotope homogenization in a magmatic chamber some light sulfur isotope enrichment of sulfides from the quartz carbonate barite fluorite sulfide veins 34 s 6 0 to 6 1 may be linked to the evolution of the magmatic source toward more mantle related sulfur species as these veins were formed after emplacement of the late mafic lamprophyre dikes

geology mineralization and fluid inclusion characteristics of the kashkasu w mo cu skarn deposit associated with a high potassic to shoshonitic igneous suite in kyrgyzstan tien shan toward a diversity of w mineralization in central asia abstract the kashkasu deposit is part of the subduction related late paleozoic late carboniferous metallogenic belt of tien shan it is associated with a multiphase monzodiorite monzonite granodiorite granite pluton of the magnetite series high k calc alkaline to shoshonitic igneous suite the deposit contains zones of w mo cu oxidized prograde and retrograde skarns with abundant andraditic garnet magnetite locally scapolite and k feldspar as well as scheelite chalcopyrite and molybdenite skarns are overprinted by quartz carbonate sericite phyllic alteration zones with scheelite and sulfides prograde calcic skarn and initial retrograde skarns were formed from a high temperature 650 c to 450 550 c high pressure 2000 bars to 600 900 bars magmatic hydrothermal low to high salinity aqueous chloride fluid the gradual fluid evolution was interrupted by the intrusion of granodiorite and likely associated release of low salinity 7 8 wt nacl equiv fluid ascent of this fluid to shallower levels and or its cooling to 400 500 c has resulted in phase separation into low salinity 2 1 3 1 wt nacl equiv vapor and coexisting brine 35 40 wt nacl equiv the boiling was coincident with most intense scheelite deposition in retrograde skarn later retrograde skarn assemblages were formed from a gaseous low to moderate salinity 3 4 8 1 wt nacl equiv fluid and then from high salinity 37 42 wt nacl equiv aqueous chloride fluids the latter being enriched in ca 17 20 wt cacl2 that could also affect scheelite deposition another cycle of fluid exsolution from crystallizing magma corresponded to quartz carbonate sericite scheelite sulfide phyllic alteration stage with the early low salinity 5 3 8 4 wt nacl equiv fluid followed by later high salinity 33 5 38 2 wt nacl equiv fluid the sulfur isotope data 34s 5 1 to 9 0 suggest significant sulfur sourcing from sedimentary rocks enriched in seawater sulfate possibly evaporites

origin and evolution of ore forming fluids of the larong w mo deposit eastern tibet constraints from fluid inclusions h o isotopes and scheelite geochemistry abstract the larong porphyry w mo deposit formed in the main collisional orogenic stage of lhasa and qiangtang terranes is the first discovered giant w mo deposit in the leiwuqi zogang metallogenic belt sanjiang region the w mo mineralization occurs as veins and stock works mainly hosted in the granodiorite porphyry monzogranite porphyry biotite granite porphyry and surrounding schist four types of fluid inclusions fis including pc type pure vapor co2 c type co2 h2o w type aqueous two phase and l type pure liquid h2o fis have been identified from stage i quartz scheelite alkaline feldspar veins stage ii including three sub stages quartz molybdenite pyrite chalcopyrite veins and stage iii quartz calcite pyrite veins the total homogenization temperatures of fis vary widely 187 437 c with multiple peaks indicating multistage fluid activities the ore forming fluids of the main mineralization stages are characterized by co2 enrichment high medium temperature 270 440 c and medium low salinity 2 4 14 4 wt nacl equiv the homogenization temperature of w type inclusions is obviously higher than that of c type inclusions and the salinity is relatively lower implying multiple immiscibility of fluids with continuous escape of co2 h o isotopic compositions suggest that the primary ore forming fluids dominantly originated from magma water mo concentrations and eu values in scheelite indicate a decreasing trend of redox state of ore fluids from stage i to stage ii to stage iii the relatively higher temperature co2 rich and oxidized fluids gradually evolved into relatively lower temperature co2 poor and reduced fluids here we propose that the decrease of temperature and oxygen fugacity and increase of s2 activity and ph values of the ore fluids caused by continuous fluid rock interaction and loss of co2 could account for the successive mineralization of w and mo at the larong deposit

architecture and mineral deposit settings of the altaid orogenic collage a revised model abstract the altaids are an orogenic collage of neoproterozoic paleozoic rocks located in the center of eurasia this collage consists of only three oroclinally bent neoproterozoic early paleozoic magmatic arcs kipchak tuva mongol and mugodzhar rudny altai separated by sutures of their former backarc basins which were stitched by new generations of overlapping magmatic arcs in addition the altaids host accreted fragments of the neoproterozoic to early paleozoic oceanic island chains and neoproterozoic to cenozoic plume related magmatic rocks superimposed on the accreted fragments all these assemblages host important many world class late proterozoic to early mesozoic gold copper molybdenum lead zinc nickel and other deposits of various types in the late proterozoic during breakup of the supercontinent rodinia the kipchak and tuva mongol magmatic arcs were rifted off eastern europe siberia and laurentia to produce oceanic backarc basins in the late ordovician the siberian craton began its clockwise rotation with respect to eastern europe and this coincides with the beginning of formation of the mugodzhar rudny altai arc behind the kipchak arc these earlier arcs produced mostly cu pb zn vms deposits although some important intrusion related orogenic au deposits formed during arc arc collision events in the middle cambrian and late ordovician the clockwise rotation of siberia continued through the paleozoic until the early permian producing several episodes of oroclinal bending strike slip duplication and reorganization of the magmatic arcs to produce the overlapping kazakh mongol and zharma saur valerianov beltau kurama arcs that welded the extinct kipchak and tuva mongol arcs this resulted in amalgamation of the western portion of the altaid orogenic collage in the late paleozoic its eastern portion amalgamated only in the early mesozoic and was overlapped by the transbaikal magmatic arc which developed in response to subduction of the oceanic crust of the paleo pacific ocean several world class cu mo porphyry cu pb zn vms and intrusion related au mineral camps which formed in the altaids at this stage coincided with the episodes of plate reorganization and oroclinal bending of magmatic arcs major pb zn and cu sedimentary rock hosted deposits of kazakhstan and central asia formed in backarc rifts which developed on the earlier amalgamated fragments major orogenic gold deposits are intrusion related deposits often occurring within black shale bearing sutured backarc basins with oceanic crust after amalgamation of the western altaids this part of the collage and adjacent cratons were affected by the siberian superplume which ascended at the permian triassic transition this plume related magmatism produced various deposits such as famous ni cu pge deposits of norilsk in the northwest of the siberian craton in the early mesozoic the eastern altaids were oroclinally bent together with the overlapping transbaikal magmatic arc in response to the northward migration and anti clockwise rotation of the north china craton the following collision of the eastern portion of the altaid collage with the siberian craton formed the mongol okhotsk suture zone which still links the accretionary wedges of central mongolia and circum pacific belts in the late mesozoic a system of continent scale conjugate northwest trending and northeast trending strike slip faults developed in response to the southward propagation of the siberian craton with subsequent post mineral offset of some metallogenic belts for as much as 70 400 km possibly in response to spreading in the canadian basin india asia collision rejuvenated some of these faults and generated a system of impact rifts

fluid inclusions in skarns carbonate replacement deposits fluid inclusions in ore skarn minerals reflect the physiochemical nature of the solutions present during the skarn forming process because of the dense nature of skarn minerals and the dynamic processes operative during skarn genesis sufficient primary fluid inclusions are usually present ore skarn solutions as opposed to metamorphic skarn or ore vein solutions have much higher cacl2 contents and usually very high formation temperatures 500 c and salinities 40 wt t d s temperatures and salinities generally decrease away from the solution source both in time and space the gradients found at greater distances from the source in distal far from contact skarns tend to be less e g 210 350 c for a particular skarn stage to that in proximal near contact skarns e g 400 650 c this information is useful for delineating the parts of such a hydrothermal system temperatures also tend to decrease with time which is reflected by the superimposition of various overprinting retrograde mineral stages in a few areas e g naica mexico intermittent boiling of ore solutions occurs periodically elevating both temperatures and salinities but commonly boiling only occurs early in skarn genesis just after an early commonly lower temperature phase most fluid inclusions represent a mix of exhaust or reacted solutions with minor unreacted or new pre ore solution components limited data on the distribution of elements present in fluid inclusions that do not normally take part in skarn genesis na k and cl indicate that their proportions reflect the nature of the associated pluton high kc1 contents are found in skarns adjacent to high k granitoids whereas high nacl contents are found in skarns adjacent to calcic granitoids in many examples daughter minerals present in minor proportions in opened fluid inclusion cavities reflect the metal characteristics of the ore solution small rare earth metal tungsten zinc and copper daughter minerals have been identified the temperature and or salinity data for skarns of different metal or geological type is not particularly useful to delineate whether a skarn locality is part of a more complex as yet unexplored system solutions in pb zn skarns tend to be lower temperature 150 400 c and more dilute 30 wt t d s than in other skarn types but exceptions occur

earthquake response and sliding displacement of submarine sensitive clay slopes abstract many submarine landslides occur through marine sensitive clay layers and the strain softening behavior plays a key role the changing soil properties induced by various disturbances will have marked impact on earthquake performance of submarine clay slopes in the present study undrained triaxial compression tests on reconsolidated samples of a soft sensitive marine clay were conducted and a soil disturbance dependent simple constitutive model is proposed for describing post peak nonlinear strain softening behavior of sensitive clays based on experimental results and then is implemented in quiver code to perform one dimensional seismic response analysis of mild infinite slopes to address the relative importance of soil disturbance effect on the site response and sliding displacement of submerged slopes during seismic loading detailed laboratory test descriptions and results of a soft sensitive marine clay model formulations and comprehensive computational efforts are presented parametric study of site response analysis focusing on the effects of soil disturbance degree and depth on generic clay grounds with varying sloping angles subjected to harmonic and earthquake loadings are performed the predicted acceleration amplification maximum shear strains and permanent displacements provide insight of earthquake performance of submarine sensitive clay slopes the main findings are drawn based on several key concepts first undisturbed sensitive clay is typically stiffer and stronger than disturbed clay consolidated at the same stress level and hence unless strain softening is triggered structured sensitive clay will perform better than insensitive clay of the same residual strength second post peak softening at shallow depth will lead to strain localization on a thin layer which is the main cause of sudden change of upward wave propagation characteristics and large permanent displacement at seabed surface of mild submarine clay slope thirdly soil disturbance degrees and depths have very marked effects on seismic response and displacement performance of sensitive clay slopes and such effect will be further enhanced by slope angle or earthquake intensity which should be cautiously treated in engineering design

repeatable process for seismic microzonation using 1 d site specific response spectra assessment approaches application to the city of nice france abstract we are testing three different approaches to assess the site effects based on 1d soil column data the first method follows the eurocodes 8 ec8 approach based on the determination of vs30 soil classes the second one is based on an empirical relationship between vs30 and the fundamental resonance frequency of the site f0 with a response spectra amplification function proposed by cadet et al 2013 and the last one is the application of a 1 d equivalent linear simulation then we propose a repeatable methodology to define the zonation and the associated surface response spectrum from individual results this methodology uses a shape recognition algorithm to build homogeneous response spectra zones and the definition of a specific ec8 like response spectrum adjusted to the distribution of the response spectra in each zone this has been applied to downtown nice a city located on the french riviera that faces the highest seismic hazard in the french mainland area the city is built on two different sedimentary valleys that are prone to lithological site effects the ground acceleration around 1 8 hz can be 20 times higher in the valleys than the one recorded on the surrounding jurassic rock outcrop we defined a 3d geotechnical model composed of 9 homogenous soil layers the surface elastic response spectra in pseudo acceleration obtained with the three methods are compared on the whole city the results indicate that the amplification functions methodology proposed by cadet et al 2012b provides results closer to the numerical simulations compared to ec8 in addition in five sites of the french permanent accelerometric network rap resif located in the valley of nice the site to reference response spectra ratio from the numerical simulations and the spectra amplification function proposed by cadet et al 2012b were compared to earthquake recordings data although the spectra amplification functions are closer to the observations both evaluations underestimate the amplification as they could not capture complex site geometry using the repeatable zonation process on the response spectra from the amplification function three different zones are defined the associated specific response spectra are significantly different from the recommended ec8 response spectra

some metallogenic features of gold and copper deposits related to alkaline rocks and consequences for exploration porphyry copper gold skarn copper gold sediment hosted carlin style gold breccia pipe low sulphidation epithermal gold pluton related mesothermal or orogenic gold vein and volcanogenic massive sulphide deposits associated with alkaline rocks are commonly broadly similar to those hosted by their calc alkaline counterparts in contrast porphyry molybdenum gold deposits are confined to alkaline igneous centres alkaline suites are notably deficient in high sulphidation epithermal gold deposits and even in the advanced argillic lithocaps which host them this is surprising given that the required oxidised sulphur species are seemingly more abundant than in calc alkaline igneous centres highly efficient buffering of acidic fluid by metasomatised alkaline rocks may offer a viable explanation all types of intrusion related zinc deposits also appear to be poorly developed in alkaline provinces the characteristics of several gold and copper deposits associated with alkaline rocks including the giant porgera cripple creek ladolam olympic dam and phalaborwa examples are judged to diverge appreciably from their most closely related deposit types rendering them arguably unique most of these aberrant mineralisation styles may be due to variations in magmatic fluid compositional and liberation characteristics consequent upon the extreme diversity of ore related alkaline magmas most types of gold and copper deposits developed in calc alkaline provinces also constitute exploration targets in and around alkaline igneous centres although porphyry copper gold and low sulphidation epithermal gold deposits are considered to possess the greatest potential perhaps of even greater interest however is the possibility of encountering unconventional giant gold and copper deposits which lack closely analogous examples if already defined aberrant deposits are truly unique then exploration designed specifically to detect additional examples is pointless furthermore exploration for new unique deposits is difficult because their defining geological parameters are unknown alkaline rocks within or behind calc alkaline arcs at convergent plate boundaries probably offer the greatest exploration potential although anorogenic intracontinental extensional settings should not be ignored

liquefaction case studies of gravelly soils during the 2008 wenchuan earthquake abstract the 2008 wenchuan earthquake caused widespread liquefaction of gravelly soils i e gravelly sands and sandy gravels which phenomena show many differences compared to those of typical sands to study the liquefaction mechanism and triggering evaluation of gravelly soils during this event comprehensive case studies with measurement of shear wave velocity on both liquefied and non liquefied sites were carried out according to a suite of recommended procedures for site investigation field testing and data processing three typical cases were provided to illustrate the distinct characteristics of ground motion liquefaction manifestation soil profiles and field testing and explore the possible mechanisms of liquefaction eighty one well identified case histories were obtained which feature the updated estimation of ground motion parameters from the usgs shakemap and the probabilistic treatment of the datasets the preliminary analyses on liquefaction triggering boundary curves shear wave velocities of these case histories and the applicability of the ishihara criterion 1985 indicate that the gravel content plays a key role in the liquefaction mechanism and the consequences of gravelly soil deposits and the liquefaction evaluation of gravelly sands and sandy gravels should be treated separately

some new data on the genesis of the linghou cu pb zn polymetallic deposit based on the study of fluid inclusions and c h o s pb isotopes abstract the linghou deposit located near hangzhou city of zhejiang province eastern china is a medium sized polymetallic sulfide deposit associated with granitic intrusion this deposit is structurally and lithologically controlled and commonly characterized by ore veins or irregular ore lenses in this deposit two mineralization events were identified of which the former produced the cu au ag orebodies while the latter formed pb zn cu orebodies silicification and calc silicate skarn type phyllic and carbonate alternation are four principal types of hydrothermal alteration the early cu au ag and late pb zn cu mineralizations are characterized by quartz sericite pyrite chalcopyrite bornite au ag minerals magnetite molybdenite and calcite dolomite sphalerite pyrite chalcopyrite galena respectively calcite clusters and calcite quartz vein are formed during the late hydrothermal stage the nacl h 2 o co 2 system fluid coexisting with nacl h 2 o system fluid and showing the similar homogenization temperatures 385 c and 356 c respectively and different salinities 16 89 21 68 wt nacl eqv and 7 70 15 53 wt nacl eqv suggests that fluid immiscibility occurred during the cu au ag mineralization stage and might have given rise to the ore metal precipitation the ore forming fluid of the pb zn cu mineralization mainly belongs to the nacl h 2 o co 2 system of high temperature 401 c and mid high salinity 10 79 wt nacl eqv fluids trapped in the quartz chalcopyrite vein cu au ag ores pb zn cu ores and calcite clusters yielded 18 o h2o and d values varying from 5 54 to 13 11 and from 71 8 to 105 1 respectively indicating that magmatic fluids may have played an important role in two mineralization events the 13 c pdb values of the calcite change from 2 78 to 4 63 indicating that the co 3 2 or co 2 in the ore forming fluid of the pb zn cu mineralization was mainly sourced from the magmatic system although dissolution of minor marine carbonate may have also occurred during the ore forming processes the sulfide minerals have homogeneous lead isotopic compositions with 206 pb 204 pb ranging from 17 958 to 18 587 207 pb 204 pb ranging from 15 549 to 15 701 and 208 pb 204 pb ranging from 37 976 to 39 052 indicating that metallic elements of the linghou deposit came from a mixed source involving mantle and crustal components based on geological evidence fluid inclusions and h o c s pb isotopic data the linghou polymetallic deposit is interpreted as a high temperature skarn carbonate replacement type two types of mineralization are both related to the magmatic hydrothermal system with the cu au ag mineralization having a close relationship with granodiorite

synthetic fluid inclusions vi quantitative evaluation of the decrepitation behaviour of fluid inclusions in quartz at one atmosphere confining pressure the decrepitation behaviour of fluid inclusions in quartz at one atmosphere confining pressure has been evaluated using pure h2o synthetic inclusions formed by healing fractures in natural quartz three different modes of non elastic deformation referred to as stretching leakage or partial decrepitation and total decrepitation have been observed the internal pressure required to initiate non elastic deformation is inversely related to inclusion size according to the equation internal pressure kbar 4 26 d 0 423 where d is the inclusion diameter in microns regularly shaped inclusions require a higher internal pressure to initiate non elastic deformation than do irregularly shaped inclusions of similar size heating inclusions through the quartz inversion results in mechanical instability in the quartz crystal and leads to mass decrepitation of inclusions owing to structural mismatches generated by pressure gradients in the quartz around each inclusion long term heating experiments 2 years suggest that the internal pressure required to initiate non elastic deformation does not decrease significantly with time and indicates that short lived thermal fluctuations in natural systems should not alter the inclusion density and homogenization temperature inclusions that do exhibit decreased density higher homogenization temperature are however always accompanied by a change in shape from irregular to that of a negative crystal observations of this study are consistent with elasticity theory related to fracture generation and propagation around inclusions in minerals these results indicate that an inclusion will not be influenced by a neighbouring inclusion or other defect in the host phase as long as the distance between the two is 2 4 diameters of the larger of the two inclusions

regional correlations of vs30 and velocities averaged over depths less than and greater than 30 meters using velocity profiles from sites in japan california turkey and europe we find that the time averaged shear wave velocity to 30 m vs30 used as a proxy for site amplification in recent ground motion prediction equations gmpes and building codes is strongly correlated with average velocities to depths less than 30 m vsz with z being the averaging depth the correlations for sites in japan corresponding to the kik net network show that vs30 is systematically larger for ag ivenvsz than for profiles from the other regions the difference largely results from the placement of the kik net station locations on rock and rocklike sites whereas stations in the other regions are generally placed in urban areas underlain by sediments using the kik net velocity profiles we provide equations relating vs30 to vsz for z ranging from 5 to 29 m in 1 m increments these equations and those for california velocity profiles given in boore 2004b can be used to estimate vs30 from vsz for sites in which velocity profiles do not extend to 30 m the scatter of the residuals decreases with depth but even for an averaging depth of 5 m a variation in logvs30 of 1 standard deviation maps into less than a 20 uncertainty in ground motions given by recent gmpes at short periods the sensitivity of the ground motions to vs30 uncertainty is considerably larger at long periods but is less than a factor of 1 2 for averaging depths greater than about 20 m we also find that vs30 is correlated with vsz for z as great as 400 m for sites of the kik net network providing some justification for using vs30 as a site response variable for predicting ground motions at periods for which the wavelengths far exceed 30 m online material estimates of vs30 at k net stations

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

processes and ore genesis at the yaochong mo deposit henan province china abstract the yaochong mo deposit in henan province is located in the dabie orogen and its orebodies primarily occur as numerous veinlets hosted in the contact zone of the yaochong stock with the dabie complex based on vein crosscutting relationships mineral assemblages and paragenetic sequence the mineralization is divided into four stages a quartz k feldspar magnetite hematite stage a quartz k feldspar molybdenite stage a quartz polymetallic sulfide mineral stage and a quartz carbonate stage three types of fluid inclusions have been recognized in the quartz co 2 bearing fluid inclusions h 2 o rich fluid inclusions and solid bearing fluid inclusions microthermometric analyses of the fluid inclusions suggest that the fluids evolved gradually during the ore forming process in stages 1 2 3 and 4 the homogenization temperatures varied in the ranges 264 400 c 175 487 c 171 433 c and 119 172 c respectively and the salinities varied in the ranges 4 34 7 70 wt nacl equiv 2 77 32 49 wt nacl equiv 2 20 30 70 wt nacl equiv and 1 06 7 73 wt nacl equiv respectively the calculated 18 o h2o values of stages 1 2 3 and 4 ranged from 2 2 to 3 9 0 9 to 1 7 0 8 to 0 1 and 1 3 to 0 6 respectively and the 18 d values varied from 68 to 62 73 to 64 75 to 65 and 68 to 65 respectively these results show that the ore forming fluids of the yaochong molybdenum deposit were mainly derived from magmatic water which likely included a small component of meteoric water the 34 s values of pyrite and molybdenite varied from 2 9 to 1 8 and 2 7 to 1 6 respectively and the 206 pb 204 pb 207 pb 204 pb and 208 pb 204 pb values of the sulfide minerals ranged from 16 193 to 16 818 15 105 to 15 288 and 36 698 to 37 307 respectively the sulfur and lead isotope compositions indicated that the ore forming constituents were derived from a deep igneous source originating in the lower crust the yaochong porphyry mo deposit may have formed in a post collision extensional setting the mo mineralization in the yaochong deposit occurred at depths of 0 87 1 68 km and phase separation and immiscibility of the ore forming fluids were critical for the formation of the deposit

reconciling fluid inclusion types fluid processes and fluid sources in skarns an example from the bismark deposit mexico the bismark deposit 8 5 mt at 8 zn 0 5 pb 0 2 cu and 50 g t ag located in northern mexico is an example of a stock contact skarn end member of a continuum of deposit types collectively called high temperature carbonate replacement deposits the deposit is hosted by massive sulfide within altered limestone adjacent to the bismark quartz monzonite stock 42 ma and the bismark fault alteration concurrently developed in both the intrusion and limestone the former contains early potassic alteration comprising k feldspar and biotite which was overprinted by kaolinite rich veins and alteration and later quartz sericite and pyrite with minor sphalerite and chalcopyrite prograde exoskarn alteration in the limestone consists of green andradite and diopside and transitional skarn comprising red brown andradite green hedenbergite and minor vesuvinite calcite fluorite and quartz the main ore stage post dates calc silicate minerals and comprises sphalerite and galena with gangue pyrite pyrrhotite calcite fluorite and quartz the entire hydrothermal system developed synchronously with faulting fluid inclusion studies reveal several distinct temporal compositional and thermal populations in pre syn and post ore quartz fluorite and calcite the earliest primary fluid inclusions are coexisting vapor rich type 2a and halite bearing type 3a type 3b contain sylvite brine inclusions 32 to 60 total wt salts that occur in pre ore fluorite trapping temperatures are estimated to have been in excess of 400 c under lithostatic pressures of 450 bar 1 5 km depth primary fluid inclusions trapped in syn ore quartz display critical to near critical behavior type 1c have moderate salinity 8 4 to 10 9 wt nacl equiv and homogenization temperatures th ranging from 351 to 438 c liquid rich type 1a and 1b calcite bearing inclusions occur as primary to secondary inclusions predominantly in fluorite and show a range in th 104 336 c and salinity 2 7 11 8 wt nacl equiv which at the higher th and salinity ranges overlap with type 1c inclusions oxygen isotope analysis was carried out on garnet quartz and calcite plus carbon isotopes in pre syn post ore and peripheral veins pre ore skarn related garnets have a 18omineral range between 3 9 and 8 4 quartz from the main ore stage range between 13 6 and 16 0 calcite from the main ore stage has 13c values of 2 9 to 5 1 and 18o values of 12 3 to 14 1 which are clearly distinct from post ore veins and peripheral prospects that have much higher 18o 16 6 27 3 and 13c 1 3 3 1 values despite the numerous fluid inclusion types only two fluid sources can be inferred namely a magmatic fluid and an external fluid that equilibrated with limestone furthermore isotopic data does not indicate any significant mixing between the two fluids although fluid inclusion data may be interpreted otherwise thus the various fluid types were likely to have formed from varying pressure temperature conditions through faulting during exsolution of magmatic fluids late stage hydrothermal fluid activity was dominated by the non magmatic fluids and was post ore

refraction microtremors data analysis and diagnostics of key hypotheses surface wave methods are quite popular for site characterization in geotechnical earthquake engineering among these techniques a particular role is taken by passive methods for their ability to yield information on the low frequency range and consequently on large depths one such passive method the refraction microtremors remi technique has been proposed as a simple alternative to 2d array techniques to estimate surface wave dispersion by using linear arrays of geophones the technique owes its name to the use of widely available instruments also adopted for seismic refraction the basic hypotheses underlying remi are that noise is distributed isotropically in azimuth or is aligned exactly with the array these conditions often are not met and in most cases they are not verified because such analysis requires an accurate approach to data processing that is rarely applied we have developed an algorithm that verifies remi s basic hypotheses by analyzing experimental data in addition we have propo

geological characteristics tectonic setting and preliminary interpretations of the jilau gold quartz vein deposit tajikistan the southern tien shan metallogenic province of central asia hosts a number of important gold resources including the jilau gold quartz vein system in western tajikistan these deposits were formed at the late stages of continent continent collision in association with subduction related magmatism metamorphism and continental margin deformation attributed to the central asian hercynian orogeny jilau is hosted by a hercynian syntectonic granitoid intrusive that was emplaced into bituminous dolomite country rocks economic mineralisation is associated with a dilational jog within a high angle oblique dextral reverse slip shear zone that was undergoing brittle ductile deformation the orebody takes the form of shear zone subparallel quartz veins and lenses that emanate from a steeply plunging ore shoot of veins and stringers within a silicified and sulphidised granodiorite core it is thought to have formed by a dynamic process in which fluid flow was governed by a fault valve mechanism numerous cycles of fluid pressure build up fault failure jog dilation fluid flow phase separation of low salinity h2o co2 ch4 n2 fluids and sealing took place gold appears together with scheelite and bismuth minerals predominantly as inclusions in arsenopyrite in quartz veins and altered wall rock and is mainly associated with quartz containing fluid inclusions enriched in ch4 the correlation between high gold grades and high ch4 concentrations suggests that components of the mineralising fluids were derived from or passed through the reducing carbonaceous rocks in the contact aureole of the intrusive the occurrence of au and w in an adjacent hercynian skarn deposit and in the jilau orebody infers that the ore metals in both these systems were ultimately derived from a magmatic source

geology mineralization and fluid inclusion characteristics of the lermontovskoe reduced type tungsten cu au bi skarn deposit sikhote alin russia abstract the lermontovskoe deposit 48 kt wo 3 average 2 6 wo 3 0 24 cu 0 23 g t au is situated in a w sn au metallogenic belt that formed in a collisional tectonic environment this tungsten skarn deposit has a w au as bi te sb signature that suggests an affinity with reduced intrusion related au deposits the deposit is associated with an intrusion that is part of the ilmenite series high k peraluminous granitoid granodiorite to granite suite these rocks formed via mantle magma induced melting of crustal sources the deposit comprises reduced type pyroxene dominated prograde and retrograde skarns followed by hydrosilicate amphibole chlorite pyrrhotite scheelite quartz and phyllic muscovite sericite carbonate albite quartz scheelite sulfide with abundant apatite alteration assemblages fluid inclusions from the skarn assemblages indicate high temperature 500 c high pressure 1400 1500 bars and high salinity 53 60 wt nacl equiv magmatic hydrothermal fluids they were post dated by high carbonic methane dominate low salinity fluid at the hydrosilicate alteration stage these fluids boiled at 360 380 c and 1300 1400 bars the subsequent phyllic alteration started again with a high temperature 450 c high pressure 1000 1100 bars and high salinity 42 47 wt nacl equiv fluid with further incursion of high carbonic methane dominated low salinity fluid that boiled at 390 420 c and 1150 1200 bars the latest phyllic alteration included the lower temperature 340 360 c lower pressure 370 400 bars high carbonic methane dominated but with higher co 2 fraction low salinity fluid and then the low temperature 250 300 c h 2 o co 2 ch 4 nacl fluid with both fluids boiled at the deposit level the high salinity aqueous fluids are interpreted to have come from crystallizing granitoid magma whereas the reduced high carbonic fluids probably came from a deeper mafic magma source both of these fluids potentially contributed to the w au as bi te sb metal budget decreasing temperatures coupled with high aca 2 and fluid boiling promoted scheelite deposition at all post skarn hydrothermal stages the deposit is characterized by limited downdip extent of mineralized zones and abundant coarse grained muscovite quartz apatite scheelite aggregates that formed at the phyllic alteration stage together with presence of high temperature high pressure and high salinity fluids directly exsolving from crystallizing magma this suggests a root level of the mineralized magmatic hydrothermal system of reduced w skarn deposits

fluid inclusion and isotopic c h o s and pb constraints on the origin of late mesozoic vein type w mineralization in northern guangdong south china abstract northern guangdong of south china occurs many large tungsten deposits including shirenzhang meiziwo and yaoling quartz vein type wolframite deposits in this study we carried out a detailed study on fluid inclusions and c h o s pb isotopic analyses of mineral separates for these three deposits in order to resolve the origin and evolution of ore forming fluids and the ore deposition mechanism the ore veins in these deposits present a similar mineral paragenesis that could be divided into three stages i pre ore stage ii syn ore stage and iii post ore stage the pre ore stage is the magmatic hydrothermal transition stage which is marked by fluid exsolution from the highly fractionated granites accompanied with potassic alteration and greisenization the syn ore stage can be further divided into two stages silicate oxide stage stage ii 1 that is characterized by significant tin tungsten mineral deposition and sulfide stage stage ii 2 that is characterized by abundant sulfide minerals deposition the post ore stage is dominated by quartz and fluorite the three deposits show similar temperature and salinity variations for syn ore and post ore stages in the shirenzhang deposit the fluid temperature and salinity range from 239 to 301 c and 1 4 to 8 7 wt nacl equiv in stage ii 1 from 206 to 256 c and 1 4 to 7 0 wt nacl equiv in stage ii 2 and from 186 to 236 c and 1 4 to 8 6 wt nacl equiv in stage iii in the meiziwo deposit the fluid temperature and salinity range from 242 to 310 c and 1 1 to 8 6 wt nacl equiv in stage ii 1 from 196 to 252 c and 1 4 to 8 1 wt nacl equiv in stage ii 2 and from 188 to 234 c and 1 2 to 7 3 wt nacl equiv in stage iii in the yaoling deposit the fluid temperature and salinity range from 230 to 304 c and 1 2 to 9 0 wt nacl equiv in stage ii 1 from 203 to 258 c and 1 4 to 6 5 wt nacl equiv in stage ii 2 and from 184 to 231 c and 1 6 to 8 3 wt nacl equiv in stage iii the ore forming fluids in the three deposits belong to a medium temperature low salinity h2o nacl system with trace amounts of volatile components including co2 ch4 and n2 the c h o isotope data 13cco2 18 9 to 6 7 18owater 1 1 to 6 3 dh2o 78 to 55 indicate that the ore forming fluids were mainly magmatic water which might be modified by fluid rock interaction and mixing with meteoric water sulfur 34s 7 0 to 0 3 and pb isotope data 206pb 204pb 18 531 18 693 207pb 204pb 15 728 15 753 208pb 204pb 38 902 39 081 suggest that the ore metal and sulfur are of magmatic origin the involvement of both organic matter in metasedimentary rocks during fluid rock interaction and oxidized meteoric water may have been responsible for the negative 34s and 13c values fluid boiling fluid rock interaction and minor input of meteoric water might have been effective factors for the precipitation of wolframite cassiterite and scheelite the sulfide precipitation may have resulted from cooling and dilution of magmatic fluids by mixing with meteoric water

geology mineralization and fluid inclusion study of the kuru tegerek au cu mo skarn deposit in the middle tien shan kyrgyzstan the kuru tegerek cu au mo deposit is situated in a system of late carboniferous subduction related magmatic arcs of the middle tien shan which together constitute a metallogenic belt of cu au mo w porphyry with local skarns deposits the deposit is related to magnetite series gabbro diorite to tonalite intrusion it contains prograde magnesian and calcic skarns with abundant magnetite associated with gabbro diorite and retrograde skarn with cu mineralization formed after intrusion of tonalite subsequent propylitic alteration introduced abundant chalcopyrite and pyrrhotite and native au culminating in zones overprinting magnetite and garnet skarn later quartz muscovite carbonate veins formed after intrusion of late mafic quartz monzogabbro dikes contain chalcopyrite pyrite arsenopyrite and other sulfides and sulfosalts tellurides and native au the earliest retrograde skarn garnet contains gaseous low salinity 1 7 3 4 wt nacl eq fluid inclusions homogenizing at 460 500 c into vapor indicating that the early fluid released from crystallizing magma was a low density vapor it was followed by more saline 4 0 5 0 wt nacl eq high temperature 400 440 c aqueous fluid as fluid release from the magma progressed boiling of this fluid at temperatures of 420 to 370 c and a pressure of 350 300 bar produced a low salinity 0 6 1 2 wt nacl eq essentially gaseous and high salinity from 39 to 31 wt nacl eq brine with possible metal including cu partitioning into both gaseous and aqueous saline phases boiling was coeval with sulfide deposition in the retrograde skarn the latest episode of the retrograde skarn stage included direct separation of saline 40 42 wt nacl eq fluid from crystallizing magma the separation of saline 40 to 14 wt nacl eq fluids from a crystallizing magmatic melt continued during the propylitic stage when fluid cooling from 370 to 320 c together with decreasing fo2 caused cu and especially au precipitation a new influx of possibly magma derived low salinity 4 5 6 7 wt nacl eq aqueous and then nacl co2 h2o fluids corresponds to the phyllic quartz muscovite carbonate sulfide stage these fluids may have a deeper source associated with the late mafic quartz monzogabbro dikes fluid cooling from 340 to 255 c and boiling of the nacl co2 h2o fluid together with increased fs2 increased the au endowment

a transect of 200 shallow shear velocity profiles across the los angeles basin this study assesses a 60 km north northeast south southwest transect along the san gabriel river for shallow shear velocities in san gabriel valley and the los angeles basin of southern california we assessed a total of 214 sites 199 along the transect at 300 m spacing during a one week field campaign with the refraction microtremor remi technique the transect9s maximum 30 m shear velocity vs30 occurs in coarse alluvium of san gabriel valley where the san gabriel river exits the san gabriel mountains at 730 m sec upper national earthquake hazards reduction program nehrp site class c much of the northeast section of the transect in san gabriel valley is also nehrp class c or near the cd class boundary the section of the transect south from whittier narrows to seal beach shows nehrp d velocities in active alluvium the transect9s lowest vs30 230 m sec at the alamitos bay estuary is also classed as nehrp d an increase toward the nehrp cd class boundary occurs at the shoreline beach outside alamitos bay confirmed by additional measurements on seal beach our measured vs30 values generally show good correlation with published site classification maps and existing borehole data sets there is no evidence in our data for an increase in velocity predicted by wills et al 2000 at their cd to bc site classification boundary at the san gabriel mountains front nor for any decrease at their d to de class boundary at alamitos bay very large vs30 variations exist in soil and geologic units sampled by our survey the vs30 variations we measured are smaller than vs30 variations of 30 or more we found between closely spaced

faster better shear wave velocity to 100 meters depth from refraction microtremor arrays current techniques of estimating shallow shear velocities for assessment of earthquake site response are too costly for use at most construction sites they require large sources to be effective in noisy urban settings or specialized independent recorders laid out in an extensive array this work shows that microtremor noise recordings made on 200 m long lines of seismic refraction equipment can estimate shear velocity with 20 accuracy often to 100 m depths the combination of commonly available equipment simple recording with no source a wavefield transformation data processing technique and an interactive rayleigh wave dispersion modeling tool exploits the most effective aspects of the microtremor spectral analysis of surface wave sasw and multichannel analysis of surface wave masw techniques the slowness frequency wavefield transformation is particularly effective in allowing accurate picking of rayleigh wave phase velocity dispersion curves despite the presence of waves propagating across the linear array at high apparent velocities higher mode rayleigh waves body waves air waves and incoherent noise two locations illustrate the application of this technique in detail coincident with a large accelerometer microtremor array in reno nevada and atop a borehole logged for shear velocity in newhall california refraction equipment could duplicate microtremor results above 3 hz but could not estimate velocities deeper than 100 m refraction microtremor cannot duplicate the detail in the velocity profile yielded by a suspension logger but can match the average velocity of 10 to 20 m depth intervals and suggest structure below the 100 m logged depth of the hole eight additional examples from southern california and new zealand demonstrate that the refraction microtremor technique quickly produces good results from a wide range of hard and soft sites

evaluation of site effect within the tectonic basin in the northern side of ankara abstract this study mainly concentrates on the determination of site effects for the plio quaternary and especially alluvial soils of the cubuk district and its close vicinity in ankara turkey in the study area particularly in the vicinity of the asymmetric graben that has formed due to the tectonic activities along the ne sw trending normal faults a microtremor survey was implemented to identify the local site response under a possible seismic event the results were compared and correlated by using passive and active surface wave measurements engineering geological and geotechnical deep borehole logs along with information on local geology and geological tectonic setting regarding the microtremor results larger fundamental periods were acquired than expected over the area and the effect of the tectonic deformation on the stiffness of the soils was also observed at either the h v curves or the shear wave velocity profiles the results have demonstrated that geotechnical information down to a depth of 30 m may not be compared with the h v parameters the h v amplitudes were not always accompanied with the higher periods in the quaternary sediments this could be due to the basin and basin edge effects observed particularly at the center and boundary of the basin respectively additionally the microtremor survey showed that the spectral ratio amplitudes derived by the h v ratio are debatable and are not a direct indicator of local soil behavior under a seismic excitation

geology and structural evolution of the muruntau gold deposit kyzylkum desert uzbekistan abstract the muruntau gold deposit in the kyzylkum desert of uzbekistan is the largest single deposit 1100 tonnes of gold of the class of low sulfide syndeformation synigenous gold deposits formed in the brittle ductile transition zone of the crust within transpressional shear zones hosted by the cambrian to ordovician besopan suite the ores were deposited in pre existing thrust fault and metamorphism related permeabilities and in synmineralization dilational zones created in a large fault related fold the besopan suite is a 5 000 m thick sequence of turbiditic siltstones shales and sandstones the ore is primarily localized at the base of the besopan 3 unit which is a 2 000 m thick series of carbonaceous shales siltstones sandstones and cherts initial gold deposition took place within the sangruntau tamdytau shear zone which was developed along the stratigraphic contact between the besopan 3 and besopan 4 units during the mineralization process folding of the besopan suite and a left step adjustment in the sangruntau tamdytau shear zone were caused by two concurrent events 1 the activation of the left lateral muruntau daugyztau shear zone that developed at nearly a 90 angle to the preceding shear zone and 2 the intrusion of granitoid plutons these structural events also resulted in the refocusing of hydrothermal fluid flow into new zones of permeability

mineral deposits of canada a synthesis of major deposit types district metallogeny the evolution of geological provinces and exploration methods wayne d goodfellow editor 1 068 pp geological association of canada mineral deposits division special publication no 5 2007 hardcover isbn 13 978 1 897095 24 9 price members cdn 60 00 non members cdn 80 00 following in the footsteps of other landmark reviews of major ore producing countries such as australia hughes 1990 solomon and groves 1994 and south africa anhaeusser and maske 1986 this substantial 1 000 pages monograph is a great achievement that should be in every geologic research library in the world in many ways it sets a new standard most notably in that all figures and photographs are in color and that the entire volume is available in electronic form both as an included dvd and mostly on the gac website it is common in such compendia to have a spectacular cover photo or frontispiece to catch the reader s attention and this book does not disappoint the frontispiece photo is of a 61 8 kg sample from the dome mine timmins ontario and is stated to contain 20 wt percent gold at today s prices the gold alone would be worth 1 5 million dollars

geology mineralization and fluid inclusion characteristics of the kensu w mo skarn and mo w cu au alkalic porphyry deposit tien shan kyrgyzstan the kensu deposit is located within a large metallogenic belt of w mo cu mo w au au and pb zn deposits along the late paleozoic active continental margin of tien shan the deposit is related to a small late carboniferous to early permian multiphase gabbro monzonite syenite granite pluton representing an alkaline potassic shoshonitic suite the igneous rocks are related to a deep rooted magmatic source but the pluton emplacement corresponds to shallow porphyry levels the deposit represents an example of a complex w rich alkalic magmatic hydrothermal system that complements the typical mineral deposits related to shoshonitic igneous suites it contains large bodies of w mo skarn of the oxidized type with abundant andradite garnet scapolite k na feldspars and fe oxides magnetite hematite the skarns are overprinted and surrounded by extensive halos of stockwork disseminated porphyry style mo w mo w cu pb zn and au w mineralization with propylitic chlorite amphibole epidote dominated and phyllic quartz sericite carbonate sulfide alteration assemblages consistent with the oxidized nature of the major mineral assemblages the deposit may represent the oxidized lithophile w mo cu au metallogenic type the hydrothermal stages alternate with magmatic phases and fluid inclusion data show the predominance of high temperature 550 450 c high pressure 1 200 700 bars and high salinity 60 45 wt nacl equiv magmatic hydrothermal fluid at prograde and early retrograde skarn stages with its possible direct exsolution from crystallizing magma the general trend of cooling and dilution was complicated by the influx of higher temperature and higher salinity fluid that correlates to the intrusion of quartz monzonite and the initial stages of its degassing and cooling this more advanced phase of magmatic differentiation likely corresponded to the enrichment of residual melt and related magmatic fluids in w and mo intense fluid boiling and phase separation triggered the deposition of molybdoscheelite in skarns that formed at t 625 500 c and p 510 300 bars and continued to a nonboiling fluid at t 420 370 c and p 1 150 750 bars mineralization in propylitic alteration zones was formed by highly to moderately saline nonboiling fluids late quartz sericite carbonate sulfide stage involved both high to low salinity aqueous fluids and co2 rich fluids under decreasing temperature from 400 c to 200 300 c and varying pressure from 1 200 bars to 750 600 bars

formation of anhydrous and hydrous skarn in cu au ore deposits by magmatic fluids most skarn ore deposits are characterized by two distinctly different alteration styles an early prograde stage with anhydrous minerals such as garnet and pyroxene forms from relatively high temperature hypersaline liquid a later retrograde stage with hydrous minerals such as epidote amphibole and chlorite plus sulfide ore minerals forms from lower temperature lower salinity fluids these two alteration stages commonly have been thought to reflect a dominance of magmatic and meteoric water respectively with relevance to the source of ore metals we report data from two different skarn systems one being part of the world s largest cu au resource stable isotope compositions of anhydrous and hydrous alteration minerals from both deposits indicate a magmatic source for both the prograde and retrograde stages 18o averages 5 0 per mil for garnet range 3 4 7 2 6 5 per mil for pyroxene 4 3 8 2 and 7 1 per mil for amphibole 4 3 8 7 the d values of late amphibole are more complex with magmatic values 77 to 78 for one deposit and both magmatic and lighter values for another deposit that could be explained either by magmatic degassing or by limited mixing with meteoric water we conclude that the differences in fluid composition prograde versus retrograde stages resulted from a magmatic fluid that intersected its solvus during the early stage creating vapor and hypersaline liquid whereas in the later stage this magmatic fluid did not intersect its solvus because it followed a different cooling path this late low salinity liquid only boiled once its vapor pressure curve was reached causing sulfide ore to precipitate during the retrograde stage

influence of the vs profiles beyond 30 m depth on linear site effects assessment from the kik net data site effects may be assessed using a standard soil classification parameter vs30 the harmonic average shear wave velocity in the first 30 m however this index does not account for the complexity of the velocity profile especially its variability at depth in the present study in addition to vs30 we propose consideration of the gradient of the vs profile from 0 to 30 m depth denoted b30 a lower gradient value means low velocity increases with depth a higher gradient indicates a rapid velocity increase with depth in the shallow layers in addition we consider the fundamental resonance frequency of the soil f0 which has been shown to be a relevant parameter for site effect assessment and which is obtained from the empirical site response using the japanese kik net database we analyze the variability of the vs profiles and the empirical borehole site responses of selected sites through the vs30 the velocity gradient b30 and f0 we select 289 sites for which the 1d linear numerical modeling is close to the empirical site response and a vs at the downhole station is greater than 1000 m s for a given vs30 class b30 and f0 can be used to distinguish between two types of sites deep sedimentary sites and sites with high velocity contrast at shallow depths we find that even if the gradient is calculated using shallow information its use improves the site amplification characterization compared to using only vs30 by reducing the intersite site response variability as expected however this improvement is limited for deep sedimentary sites on the other hand f0 is able to reduce the intersite response variability for deep sedimentary sites even though it is limited to specific vs30 classes thus the combined use of vs30 b30 and f0 improves the assessment of linear site amplification

a predictive equation for the vertical to horizontal ratio of ground motion at rock sites based on shear wave velocity profiles from japan and switzerland abstract ratios of vertical to horizontal v h ground motion are important for the computation of scenario compatible vertical design spectra they are therefore a crucial aspect of seismic hazard analysis we characterize the v h ratio at rock sites in terms of the recording site s average quarter wavelength velocity a predictive equation is presented which can be used for reconstructing the expected v h ratio of the 5 damped response and fourier spectra for rock sites given a known shear wave velocity profile the equation is based on the regression analysis of two datasets one from switzerland and one from japan the two datasets allow us to analyze well characterized hard rock sites in switzerland using small earthquakes m w 2 while the magnitude range is increased up to events of m w 7 3 using strong motion recordings from japan s kik net seismic network it is shown that a correlation exists between the quarter wavelength velocity at a given frequency and the v h ground motion ratio small differences possibly due to velocity measurement bias or topographical and basin effects existed when analyzing the individual regional datasets apart from near source distances r v h no clear magnitude or distance dependence of the v h ratios is present in either of the datasets of earthquake recordings we show that the same correlation exists for response spectra and fourier spectra of recorded ground motion a similar correlation was derived for ambient vibrations recorded at swiss station sites resulting in larger values of v h at a given frequency and thereby indicating that v h is sensitive to the composition of the wave field finally uncertainties in the v h models are presented we separate the sources of uncertainty into source and site specific components and present the single site sigma uncertainty measure for site specific hazard analyses

determining phase volumes of mixed co 2 h 2 o inclusions using microthermometric measurements a new graphical technique has been developed which permits the composition and volumetric properties of mixed co2 h2o inclusions to be determined using microthermometric measurements if the values of only two of the four variables 1 density of the co2 phase derived from the temperature and mode of partial homogenization 2 temperature and mode of total homogenization 3 volume fraction of the co2 phase at 40 c and 4 molar fraction of co2 of a mixed co2 h2o inclusion are known the values of the other two variables can be taken from a diagram depicting the relationships between all four variables the diagram can be used to derive the volume fraction of the co2 phase from measurements of the partial and total homogenization temperature it can also be employed in the opposite sense for determining the theoretical homogenization temperature of an inclusion which decrepitates before reaching total homogenization provided a good visual phase volume estimate is available the graphical technique can also be applied to mixed co2 h2o inclusions which contain 6 wt nacl

metallogeny of the saryjaz ore district eastern kyrgyz tien shan abstract the saryjaz ore district relates to the tien shan metallogenic belt in the eastern part of the kokshal segment of the tien shan collisional belt the regional structure is known as the saryjaz syntaxis also partially capturing the middle and south tien shan the ore district was formed during multiple changes of tectonic regimes in relation to subduction of the turkestan ocean in the silurian to the carboniferous to the collision of the kazakh and tarim continents in the late carboniferous to the early permian and to postcollisional permian geological events a distinctive feature of the tectonic evolution of the region is the transition from the subduction of the oceanic crust to the continental subduction of the tarim continent under the kazakh continent followed by the impact of the tarim mantle plume after the collision sinistral strike slip tectonics caused by oblique collision between the tarim and kazakh continents led to formation of postcollisional transcrustal fault zones of great importance as the main magma and ore controlling conduits these fault zones penetrated into the mantle and controlled the distribution of heat and fluid flows as well as localization of granite plutons and mineralization in the consolidated crust the metallogenic zoning of the ore district reflects its geological and structural heterogeneity relationship features of mineralization and magmatism and the varying depth of formation of mineral deposits within the south tien shan portion of the district mineralization is associated with late postcollisional permian a type granites related to a one petrogenetic series namely granite rapakivi biotite leucogranite li mica leucogranite rapakivi granites of the jangart suite were formed in the course of exhumation and melting of overheated continental slabs of the tarim craton previously subducted into the mantle leucogranite uchkoshkon complex and leucogranite li mica granite inylchek complex were formed during complex interaction of the rapakivi magma fractionation with further melting of the continental crust under the influence of the tarim mantle plume at the bottom of the collisional edifice the megamelange terrain includes togolok gold deposit and several rare tin occurrences associated with rapakivi granites of the jangart complex within the lower and middle thrust sheets the leucogranite plutons of the uchkoshkon complex control a large uchkoshkon tin deposit and a medium sized sarybulak tin polymetallic deposit within the upper thrust sheet the leucogranite li mica granite plutons of the inylchek complex control a large trudovoe tungsten tin deposit and a small atjailau tin deposit within the middle tien shan portion of the district neoproterozoic carbonaceous shales intensively deformed in a thick thrust zone accommodated a giant kumtor orogenic gold deposit it has no proven links with granites it is structurally controlled by a system of postcollisional transcrustal fault zones the spatial proximity and synchronism of permian magmatic activity in tarim 300 272 ma and a types granites in the saryjaz ore district 299 269 ma as well as the age of kumtor gold deposit 288 284 ma support a hypothesis about the influence of the tarim mantle plume upon the formation of the ore district

halogen and trace element analysis of carbonate veins and fe oxyhydroxide by la icpms implications for seafloor alteration atlantis bank sw indian ridge halogens are critical elements for transporting metals in hydrothermal solution and tracing the sources of fluids and volatiles in subduction zones this study tested the suitability of la icpms for simultaneous measurement of cl br and i with selected trace elements in altered gabbros recovered from the atlantis bank core complex close to the sw indian ridge the aim was to better understand the causes of i enrichment in low temperature carbonate and fe oxyhydroxide alteration which is intensely developed in core recovered from between 100 and 600 mbsf down hole u1473a drilled during expedition 360 of the international ocean discovery program iodp the analysis of reference materials including scapolites durango apatite usgs and nist reference glasses and volcanic glasses demonstrate cl br and i can be measured in most minerals but accuracy is limited by matrix dependent laser backgrounds false signals of cl br and i generated during sample ablation silicate reference glasses define reproducible laser backgrounds of 320 g g cl and 1 7 g g br that point to limits of quantification of 200 g g cl and 1 g g br in silicate glasses after correction for laser backgrounds in contrast laser backgrounds are much lower and possibly negligible for carbonate suggesting limits of quantification as low as 50 g g cl and 0 1 g g for br dependent on instrument sensitivity laser backgrounds for i varied between minerals and analytical sessions there was no laser background for i in apatite and under favourable conditions silicate glasses have laser backgrounds of 1 g g in addition to the laser backgrounds we report a correction for interference of doubly charged rare earth elements on br measurement which significantly improves data quality for some samples the atlantis bank alteration minerals investigated include calcite veins and fe oxyhydroxide which is intermixed with and cut by veinlets of calcite and smectite the fe oxyhydroxide contains 100 s 1000s g g cl 10s g g br and 5 30 g g i and it is strongly enriched in other trace elements including b and as most calcite veins contain 100 200 g g cl 0 4 0 9 g g br and 5 26 g g i among the halogens i is uniquely correlated with divalent cations in calcite including mg and sr consistent with its incorporation into the carbonate lattice as iodate in most cases smectite contains less i than coexisting calcite or fe oxyhydroxide but three smectite grains in one sample are exceptionally enriched with 150 240 g g i the in situ analyses support the attribution of exceptional iodine enrichment of atlantis bank lithologies to preferential adsorption of iodate over halides by fe oxyhydroxides and subsequent remobilisation with preferential fixing of iodate in carbonate dominated alteration the data demonstrate the utility of la icpms for in situ halogen studies iodine in carbonate veins can provide information about fluid oxidation state and fluid rock reaction history however further work is required to test if cl and br in carbonate can provide information about fluid sources

constraints on magma degassing beneath the far southeast porphyry cu au deposit philippines k silicate alteration in the far southeast fse porphyry cu au introduction deposit formed at 1 4 ma concentric to dikes of quartz diorite magmas become saturated with volatile components as porphyry at 2 km paleodepth the hydrothermal system consisted they ascend in the crust and either erupt or crystallize of magmatic hypersaline liquid and vapor at 550 c and 50 at depth saturated magmas that remain at depth exsolve mpa lithostatic pressure advanced argillic alteration formed at an aqueous fluid that forms a hydrothermal system on the same time over the deposit at 1 km paleodepth from acidic separation from the magma chamber burnham 1979 condensates of the vapor at 1 3 ma k silicate alteration was although part of the exsolved fluid a low density vapor overprinted by 350 c magmatic liquid 5 wt nacl equiv may discharge to the surface from passively degassing at hydrostatic pressure sericite alteration and much of the cu au volcanoes hedenquist 1995 part will remain at depth mineralization formed at this later stage evolution of the magmatic and this dense residual magmatic liquid may be asfluid composition was simulated with a magma chamber cryssociated with hydrothermal mineralization in the portallization model homogeneous crystallization during early stage phyry ore environment hedenquist lowenstern convection is assumed whereas at 50 vol crystals the chamber 1994 becomes stagnant and crystallizes from rim to core over a narrow in this paper we use evidence from a porphyry ore crystallization interval the model calculation based on a magma deposit in the philippines to determine the composition chamber with 2 km thickness at 6 km depth 150 mpa and of the fluid that exsolved from the deeper parent magma 800 c saturated melt composition at 30 vol crystals 5 the evolving composition of the magmatic fluid at the wt h2o 0 2 wt cl and dd of 40 can reproduce the depth of the ore body can then be used to place constraints chemical and isotopic compositions of the early and late magmatic on the nature of the evolved magma chamber far below fluids the most critical factor controlling the compositional evolution the porphyry ore body this approach differs from that of the model hydrothermal system is the transition from convective of other studies where a portion of the parent magma to stagnant magma chamber crystallization there is also a sharp chamber is available to study directly e g at yerington decrease in the rate of fluid exsolution associated with this transition nevada dilles 1987 which can account for the thermal collapse of the fse porphyry the far southeast fse porphyry cu au deposit system from k silicate to sericite alteration and overlying lepanto epithermal cu au ore body are

direct evolution of brine from a crystallizing silicic melt at the questa new mexico molybdenum deposit molybdenum mineralization in the southwest orebody at the questa deposit is associated with crystallization of aplite porphyry explosive brecciation and exsolution of magmatic hydrothermal fluids quartz k feldspar fluorophlogopite and molybdenite precipitated from exsolving aqueous fluids and cemented aplite porphyry and andesite wall rock clasts forming a magmatic hydrothermal breccia ore fluid inclusions in quartz in the breccia matrix trapped aqueous fluids that transported and precipitated molybdenum two fluid inclusion populations associated with molybdenite mineralization were identified the largest population commonly contains liquid vapor halite sylvite and one or more opaque daughter crystals these inclusions homogenize between 200 degrees and 500 degrees c and have a prominent mode at 360 degrees to 400 degrees c salinities vary from 31 to 57 wt percent nacl equiv low first ice melting temperatures suggest that additional fluid components possibly calcium or magnesium chlorides may be present approximately 80 percent of these inclusions homogenize by halite dissolution phase equilibria constraints require that these inclusions trapped fluids in the vapor absent field the remaining saline inclusions homogenize to liquid at temperatures above halite dissolution temperatures significantly the saline fluid did not coexist with a low density aqueous fluid a second population of inclusions contains fluids with salinities of 2 7 to 25 0 wt percent nacl equiv and homogenizes by vapor bubble disappearance vapor bubble expansion or critical behavior textural relationships and phase behavior during microthermometry indicate that these inclusions constitute a single population which formed as pressure and temperature fluctuated at near critical conditions pressure changes related to brecciation followed by crystallization and system resealing produced the observed fluids saline fluids were trapped as the system sealed following a major brecciation event these high salinity fluids were produced as the melt under pressure that increased from hydrostatic to lithostatic partitioned increasing amounts of chlorine into the exsolving aqueous fluid renewed fracturing and abrupt pressure decrease to hydrostatic conditions reduced the mass of chlorine partitioning to the exsolving fluid lower salinity fluids exsolved at near critical conditions and were trapped by inclusions that homogenize to liquid to vapor or by critical behavior the lack of cogenetic liquid and vapor rich fluid inclusions and phase equilibria constraints indicate that high salinity fluids or 57 wt nacl equiv were generated directly by the crystallizing magma and were not a product of aqueous fluid immiscibility

characterization of spectral analysis of surface waves shear wave velocity measurement uncertainty the spectral analysis of surface waves sasw method is a nondestructive test for characterization of the variation with depth of the shear modulus of soils while the testing procedure is well developed only one preliminary study has investigated measurement uncertainty associated with sasw and the methods utilized to quantify measurement uncertainty were prohibitive to routine assessment knowledge of this uncertainty and ability to include its assessment in routine testing would allow for inclusion of sasw results in reliability based design and in assessment of the spatial variability of shear modulus in this study a large sample of test data was collected from two test sites characteristic statistics statistical distribution and measurement uncertainty were determined for each phase of sasw using the empirical statistical properties and measurement uncertainty results as validation criteria an analytically based uncertainty assessment system was developed phase angle inverse phase angle and phase velocity data typically display a coefficient of variation cov of 2 and the cov for combined phase velocity data is typically 1 5 the cov for shear wave velocity is typically between 5 and 10 and thus the inversion appears to magnify measurement uncertainty phase angle inverse phase angle phase velocity and combined phase velocity data are normally distributed shear wave velocity samples at a given depth are generally normally distributed using a small sample of experimental data and the analytically based process developed in this study the measurement uncertainty of sasw test results can be assessed as part of routine testing

volatile exsolution at the dinkidi cu au porphyry deposit philippines a melt inclusion record of the initial ore forming process immiscible phases derived from degassing silicate magmas are considered to be precursors of metal bearing hydrothermal fluids in porphyry deposits the development of melt inclusion techniques provides a window into this critical period of porphyry formation when the cooling decompression and crystallization of silicate melts result in the formation of immiscible phases the record of magmatic to hydrothermal evolution is presented using inclusions in clinopyroxene phenocrysts from the syenitic balut dike one of the host rock lithologies for mineralization at the dinkidi cu au porphyry deposit philippines primary inclusions include silicate glass multiphase aggregates comprising salts silicates sulfates carbonates sulfides and oxides and highly saline aqueous fluids various analyses including in situ laser ablation inductively coupled plasma mass spectrometry of the multiphase inclusions determined elevated concentrations of cl s as tl k na and a number of metals including those that form ore grade deposits e g cu and those that do not e g mo pb zn and w at the dinkidi porphyry deposit silicate melt and multiphase salt rich inclusions in clinopyroxene are interpreted as having originally formed as immiscible phases at magmatic temperatures

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

controls on skarn mineralization and alteration at the cadia deposits new south wales australia the cadia fe cu au skarns in eastern new south wales australia are associated with the late ordovician shoshonitic cadia intrusive complex which hosts the largest mineralized intrusion related system in eastern australia both the big cadia and little cadia skarns are developed within a 40 m thick volcanic derived calcareous sandstone and adjacent units which represent the most important control on skarn formation the ore zones have undergone postore displacement along steeply dipping predominantly reverse faults without significant remobilization of ore chalcopyrite and minor native gold formed in intimate association with epidote chlorite quartz calcite and in the interstices of bladed hematite and magnetite aggregates the age of the au cu mineralizing event at cadia is constrained by 40ar 39ar dating of accompanying muscovite at 438 2 4 2 ma 1 gold to copper ratios within the skarns are generally lower than for porphyry au cu deposits at cadia particularly the high tonnage low grade cadia hill deposit ore and calc silicate gangue mineralogy are similar to other oxidized fe cu au skarns associated with porphyry deposits iron skarn at big cadia occurs several hundred meters distant from the margin of a mineralized intrusion of quartz monzonite porphyry magmatic dominated fluids reacted with carbonate in the wall rocks and produced classic skarn zonation over an 800 m interval from the intrusive contact located at cadia quarry toward more distal environments at big cadia skarn zonation comprises 1 proximal garnet pyroxene 2 intermediate garnet pyroxene scapolite and 3 distal fe au cu skarn alteration of noncalcareous metavolcanic rock units fine grained pyroxene phyric volcanic rocks and volcaniclastic rocks adjacent to the mineralizing quartz monzonite porphyry includes hydrothermal biotite k feldspar quartz hornfels and magnetite quartz biotite hornfels gold copper mineralization formed adjacent to garnet bearing veins peripheral to the main garnet rich zone indicating that garnet forming fluids carried the ore metals at little cadia and cadia east mineralization and skarn zonation similar to big cadia developed above additional intrusions of quartz monzonite porphyry retrograde hydrous alteration replaced much of the prograde garnet dominant mineralogy at cadia with the strongest overprint at little cadia the styles and distribution of alteration and mineralization suggest that the big cadia skarn formed from fluids that migrated laterally within calcareous units from strongly altered quartz monzonite phases of the cadia intrusive complex at cadia quarry at little cadia skarn formation was probably related to fluids derived from the cadia intrusive complex that migrated vertically and laterally within permeable calcareous units structural controls were important in focusing fluids and localizing the emplacement of late mineralizing phases of the cadia intrusive complex

blind shear wave velocity comparison of remi and masw results with boreholes to 200 m in santa clara valley implications for earthquake ground motion assessment multichannel analysis of surface waves masw and refraction micro tremor remi are two of the most recently developed surface acquisition techniques for determining shallow shear wave velocity we conducted a blind comparison of masw and remi results with four boreholes logged to at least 260 m for shear vel ocity in santa clara valley california to determine how closely these surface meth ods match the downhole measurements average shear wave velocity estimates to depths of 30 50 and 100 m demonstrate that the surface methods as implemented in this study can generally match borehole results to within 15 to these depths at two of the boreholes the average to 100 m depth was within 3 spectral amplifi cations predicted from the respective borehole velocity profiles similarly compare to within 15 or better from 1 to 10 hz with both the masw and remi surface method velocity profiles overall neither surface method was consistently better at matching the borehole velocity profiles or amplifications our results suggest masw and remi surface acquisition methods can both be appropriate choices for estimating shear wave velocity and can be complementary to each other in urban settings for hazards assessment

comparison of p and s wave velocity profiles obtained from surface seismic refraction reflection and downhole data high resolution seismic reflection refraction data were acquired on the ground surface at six locations to compare with near surface seismic velocity downhole measurements measurement sites were in seattle wa the san francisco bay area ca and the san fernando valley ca we quantitatively compared the data in terms of the average shear wave velocity to 30 m depth vs30 and by the ratio of the relative site amplification produced by the velocity profiles of each data type over a specified set of quarter wavelength frequencies in terms of vs30 similar values were determined from the two methods there is 15 difference at four of the six sites the vs30 values at the other two sites differ by 21 and 48 the relative site amplification factors differ generally by less than 10 for both p and s wave velocities we also found that s wave reflections and first arrival phase delays are essential for identifying velocity inversions the results suggest that seismic reflection refraction data are a fast non invasive and less expensive alternative to downhole data for determining vs30 in addition we emphasize that some p and s wave reflection travel times can directly indicate the frequencies of potentially damaging earthquake site resonances a strong correlation between the simple s wave first arrival travel time apparent velocity on the ground surface at 100 m offset from the seismic source and the vs30 value for that site is an additional unique feature of the reflection refraction data that could greatly simplify vs30 determinations

testing the applicability of correlations between topographic slope and vs30 for europe in the past few years a series of articles have been published concerning the use of topographic slope from digital elevation models dems constructed through remote sensing satellite imaging to give first order estimates of national earthquake hazards reduction program nehrp site classes based on the average shear wave velocity in the top 30 m vs30 wald and allen 2007 we evaluate the potential applicability of these methods taking advantage of a large 706 sites new database of measured and estimated vs30 values and their topographic slopes for locations in europe and the middle east novel statistical tests are performed to evaluate the predictive power of the procedure in this region we evaluate the percentage of sites correctly classified misclassified for each site class for active and stable regimes we also analyze the marginal distributions of the input vs30 and slope values and their impact on the vs30 slope correlations and we evaluate whether the method performs better than does chance we also consider the surface geology of sites and investigate whether differences in geology can help explain why certain sites are poorly classified by the method finally we use the city of thessaloniki greece as a test case for comparison between the results of a recent microzonation and the site classes predicted by vs30 slope correlations our results show that the method does a better job than blind chance for all site classes in active regions but only for class b rock and to a lesser extent class c stiff soil sites located in stable areas although the conclusions for stable areas are based on limited data we recommend that site classifications based on the vs30 slope correlations proposed by wald and allen 2007 be used only for regional or national and not local or site specific first order studies in active parts of europe and only in the absence of other more detailed information excluding sites inside small basins or those with special geological conditions that may affect results e g flat lying volcanic plateaus carbonate rocks continental glaciated terrain or a coastal location if slope is not calculated using bathymetric data

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

comparison of phase velocities from array measurements of rayleigh waves associated with microtremor and results calculated from borehole shear wave velocity profiles shear wave velocities vs are widely used for earthquake ground motion site characterization vs data are now largely obtained using borehole meth ods drilling holes however is expensive nonintrusive surface methods are inex pensive for obtaining vs information but not many comparisons with direct borehole measurements have been published because different assumptions are used in data interpretation of each surface method and public safety is involved in site character ization for engineering structures it is important to validate the surface methods by additional comparisons with borehole measurements we compare results obtained from a particular surface method array measurement of surface waves associated with microtremor with results obtained from borehole methods using a 10 element nested triangular array of 100 m aperture we measured surface wave phase veloci ties at two california sites garner valley near hemet and hollister municipal air port the garner valley site is located at an ancient lake bed where water saturated sediment overlies decomposed granite on top of granite bedrock our array was deployed at a location where seismic velocities had been determined to a depth of 500 m by borehole methods at hollister where the near surface sediment consists of clay sand and gravel we determined phase velocities using an array located close to a 60 m deep borehole where downhole velocity logs already exist because we want to assess the measurements uncomplicated by uncertainties introduced by the inversion process we compare our phase velocity results with the borehole vs depth profile by calculating fundamental mode rayleigh wave phase velocities from an earth model constructed from the borehole data for wavelengths less than 2 times of the array aperture at garner valley phase velocity results from array measure ments agree with the calculated rayleigh wave velocities to better than 11 mea surement errors become larger for wavelengths 2 times greater than the array aper ture at hollister the measured phase velocity at 3 9 hz near the upper edge of the microtremor frequency band is within 20 of the calculated rayleigh wave veloc ity because shear wave velocity is the predominant factor controlling rayleigh wave phase velocities the comparisons suggest that this nonintrusive method can provide vs information adequate for ground motion estimation

titanite in situ sims u pb geochronology elemental and nd isotopic signatures record mineralization and fluid characteristics at the pusangguo skarn deposit tibet the pusangguo skarn is a newly discovered cu pb zn deposit in the gangdese metallogenic belt tibet in order to constrain the age of the deposit and the source of hydrothermal fluids various types of titanite and coexisting minerals in the pusangguo deposit were studied the titanite occurring interstitially in fresh granodiorite is magmatic and characterized by high ree y mn and lu hf ratios and high crystallization temperatures 700 to 750 c the titanite growing with or included in diopside in the prograde endoskarn or occurring with epidote calcite and quartz in the retrograde exoskarn is hydrothermal titanite characterized by low ree y mn and lu hf ratios the titanite in the retrograde exoskarn typically contains a ree enriched early core characterized by a negative eu anomaly and an overgrowth ree depleted rim with a positive eu anomaly the secondary ion mass spectrometry u pb dating of titanite drilled from thin sections of retrograde exoskarn shows intercept ages of 14 91 0 31 ma which are consistent with the granodiorite age 14 63 0 30 ma indicating coeval emplacement of granodiorite and skarn mineralization at 14 7 ma in addition in situ epidote and calcite sr isotopes and titanite nd isotopes all analyzed in the same retrograde exoskarn thin section show similar sr nd isotopic compositions to magmatic plagioclase and granodiorite whole rock indicating that the retrograde hydrothermal fluids were directly derived from or had the same origin as the granodiorite

source of copper in the giant shimensi w cu mo polymetallic deposit south china constraints from chalcopyrite geochemistry and oxygen fugacity of ore related granites abstract porphyry type copper mineralization is generally considered to be related to ore forming fluid exsolution from oxidized magnetite bearing intermediate to felsic magmas however copper deposits associated with ilmenite bearing per aluminous evolved granites also exist and their origin remains obscure the shimensi w cu mo polymetallic deposit located in the northern segment of the jiangnan orogen south china composed mainly of the neoproterozoic shuangqiaoshan group meta sediments volcanic rocks and biotite granite is one of the largest tungsten deposits in the world the w cu mo polymetallic orebodies occur at the contact zone between the mesozoic ilmenite bearing fluorite bearing f rich highly fractionated granite and the neoproterozoic granite the reason for the accompanying cu mineralization within ilmenite bearing granites is unclear in this paper we present a detailed study of chalcopyrite geochemistry including s pb isotopes trace elements and nd isotopes and oxygen fugacity fo2 of ore related granites in the shimensi deposit to constrain the origin of copper sulfur isotope values of the sulfides give a narrow 34s interval of 3 3 to 0 5 mean 1 5 n 32 suggesting the ore forming fluid is of magmatic origin the similarity of pb isotopes of the majority of sulfides and k feldspars from mesozoic granites indicates their genetic relationship however chalcopyrite samples show a wider range of pb isotopic compositions than that of k feldspars suggesting an extra source for the ore forming fluids chalcopyrite from the ore deposit show features of lree enriched patterns variable eu negative anomalies eu eu 0 26 0 75 and la sm n values 0 77 5 93 while the two figures for the mesozoic f rich evolved granites are eu eu 0 18 0 45 and la sm n 2 42 4 09 this along with and the larger range of end values 12 4 to 2 7 of the chalcopyrites than for the mesozoic granites and neoproterozoic granite therein 8 6 to 6 2 suggest that the ore forming fluids cannot be attributed to the mesozoic granites alone the local cu enriched neoproterozoic shuangqiaoshan group rocks should have contributed to the mineralization the low bulk rocks fe3 fe2 ratios 0 02 1 00 average 0 22 fe2 enriched biotite compositions fe2 fe3 5 64 143 average 22 combined with the low ce4 ce3 ratios 3 509 average 142 negative eu anomalies eu eu 0 05 0 56 average 0 25 and low fo2 fmq 3 4 1 9 fmq 1 5 1 7 for the mesozoic magmatic zircons suggest that the granites in the shimensi deposit are relatively reduced the low oxygen fugacity below nno of granites is favorable for significant tungsten mineralization accompanying by minor cu mineralization

geology mineralization and fluid inclusion characteristics of the kumbel oxidized w cu mo skarn and au w stockwork deposit in kyrgyzstan tien shan the kumbel deposit is located within a metallogenic belt of w mo cu mo au w and au deposits along the late paleozoic active continental margin of tien shan the deposit is related to a late carboniferous multiphase pluton with successive intrusive phases from early olivine monzogabbro through monzonite quartz monzonite to granodiorite and granite with the latest monzogabbro porphyry dikes the deposit represents an example of a complex w cu mo au magmatic hydrothermal system related to magnetite series high k calc alkaline to shoshonitic igneous suite it contains large bodies of w cu mo oxidized prograde and retrograde skarns with abundant andradite garnet magnetite and especially hematite as well as k feldspar molybdoscheelite chalcopyrite and molybdenite with transitions to zones of intense quartz k feldspar with minor andradite and hematite veining the skarns are cut by quartz carbonate adularia sericite veins locally sheeted and stockworks bearing scheelite and minor cu zn pb sulfides as well as au bi te and as mineralization the association of these veins with the oxidized skarns and magnetite series intrusion is consistent with the general oxidized intrusion related w mo cu au type of deposit with an affinity to the alkalic silica saturated cu au mo porphyry deposits the fluid inclusion data show the predominance of magmatic hydrothermal aqueous chloride fluid during the formation of skarns and quartz carbonate scheelite sulfide veins the high fluid pressures 1 750 bars together with their high temperature up to 600 c and high salinity 50 60 wt nacl equiv suggest the formation of skarns and quartz k feldspar andradite hematite veins under conditions typical of magmatic hydrothermal transition depth of 4 5 km of intrusion related mineralized system possibly by exsolution of the fluids from crystallizing magma the auriferous quartz carbonate scheelite sulfide veins formed from high to moderate salinity from 40 to 20 wt nacl equiv and high pressure from 1 200 bars to 850 900 bars aqueous chloride fluids under decreasing temperature from 370 to 120 c the massive deposition of molybdoscheelite in retrograde skarn and scheelite in quartz carbonate scheelite sulfide veins could correspond to enrichment of fluids in ca up to 18 25 wt cacl2 likely from crystallizing magma

multiscale site response mapping a case study of parkfield california the scale of previously proposed methods for mapping site response ranges from global coverage down to individual urban regions typically spatial coverage and accuracy are inversely related we use the densely spaced strong motion stations in parkfield california to estimate the accuracy of different site response mapping methods and demonstrate a method for integrating multiple site response estimates from the site to the global scale this method is simply a weighted mean of a suite of different estimates where the weights are the inverse of the variance of the individual estimates thus the dominant site response model varies in space as a function of the accuracy of the different models for mapping applications site response models should be judged in terms of both spatial coverage and the degree of correlation with observed amplifications performance varies with period but in general the parkfield data show that 1 where a velocity profile is available the square root of impedance sri method outperforms the measured v s 30 30 m divided by the s wave travel time to 30 m depth and 2 where velocity profiles are unavailable the topographic slope method outperforms surficial geology for short periods but geology outperforms slope at longer periods we develop new equations to estimate site response from topographic slope derived from the next generation attenuation nga database

in situ estimate of shear wave velocity using borehole spectral analysis of surface waves tool in situ field testing has been performed over the past several years at a silty sand site in austin tex using the borehole spectral analysis of surface waves sasw tool to develop the technique and assess the validity of the method the borehole sasw tool is an inflatable pressuremeterlike device that allows surface wave measurements to be performed along the wall of an uncased borehole while varying the in situ states of stress field results demonstrate the applicability of borehole sasw testing as a method to characterize soil sites and provide information about in situ shear wave velocity and the relationship between shear wave velocity and state of stress results from a borehole sasw test conducted at the austin site are presented herein to demonstrate the applicability and validity of the method