organic molecules formed in a primordial womb primordial organic molecules may have evolved in seafloor hydrothermal systems by mineral catalysis most organic compounds decompose in 300 c vent fluid however we show that smectite type clays can protect and promote development of diverse organic compounds that may be precursors to biomolecules smectite provides a safe haven for the synthesis of organic molecules essentially like a primordial womb our experiments simulated seafloor hydrothermal conditions 300 c 100 mpa and reacted common clays montmorillonite saponite illite with dilute methanol as a source of c montmorillonite reacts under these conditions to illite while the other clays do not change we observed increased organic synthesis over time with montmorillonite during mineralogical reaction approaching equilibrium smectite contracts and organic molecules are expelled organic compounds unstable in hot fluid where the smectite reacts may survive in cooler waters outside the vent

graphitization of carbonaceous matter during metamorphism with references to carbonate and pelitic rocks of contact and regional metamorphisms japan this study is an attempt to correlate the graphitization process of carbonaceous matter during metamorphism with metamorphic grade graphitization can be parameterized using crystal structure and chemical and isotopic compositions the extent of graphitization could be characterized mainly by temperature duration of metamorphism and rock composition we compared the graphitization trends for two metamorphic terrains a contact aureole of the kasuga area and a regional metamorphic terrain of high temperature low pressure type of the ryoke metamorphic terrain in northern kiso area central japan and for two different lithologies carbonate and pelite using x ray diffractogram dta tg analysis and chemical and stable isotope analyses during contact metamorphism graphitization and carbon isotopic exchange reactions proceeded simultaneously in pelitic and carbonate rocks the decreases in basal spacing d 002 of the carbonaceous matter in carbonate rocks is greatly accelerated at temperatures higher than about 400 c furthermore carbon isotopic ratios of graphite in carbonate rocks also change to 13c enriched values implying exchange with carbonates the beginning of this enrichment of 13c in the carbonaceous matter coincides with an abrupt increase of the graphitization processes carbon isotopic shifting up to 5 in pelites could be observed as metamorphic temperature increased probably by about 400 c carbonaceous matter in pelitic rocks is sometimes a mixture of poorly crystallized organic matter and well crystallized graphite detritus dta tg analysis is an effective tool for the distinction of detrital graphitic material two sources for the original carbon isotopic composition of carbonaceous matter in pelites in the kasuga contact aureole can be distinguished about 28 and 24 regardless of the presence of detrital graphite and were mainly controlled by depositional environment of the sediments graphitization in limestones and pelitic rocks in regional metamorphism proceeds further than in a contact aureole in the low temperature range the differences in extent of graphitization between the two metamorphic regions is large however at temperatures higher than 600 c the extent of graphitization in both regions is indistinguishable the degree of graphitization is different in limestones and pelitic rocks from the ryoke metamorphic terrain we demonstrate that the graphitization involves a progressive re construction process of the crystal structure the sequence of the first appearance of crystal inter planar spacing correlates with the metamorphic grade and indicates the crystal growth of three dimensional structured graphite

textures in layered silicates progressive changes through diagenesis and low temperature metamorphism abstract phyllosilicates in samples from gulf coast cores and the martinsburg formation near lehigh gap pennsylvania which together represent a continuous sequence from mudstone to slate are shown by tem studies to possess imperfections on a massive scale and to exhibit a progressive increase in perfection through diagenesis and low grade metamorphism in shallow portions 1 750 and 2 450 m of the gulf coast core smectites have irregular and curved layers with high dislocation densities and many small angle grainlike boundaries in both the deeper portion 5 500 m of the gulf coast sediments and in the martinsburg mudstone samples gram perfection increases in illites but a complex mosaic structure with small angle grain boundaries and edge dislocations still prevails in the martinsbu g slate phyllosilicates exhibit layers which are continuous and straight and have few imperfections original clays which form at low temperatures have highly imperfect and metastable structures changes with increasing diagenesis are akin to annealing processes with increasing perfection of grains being an approach to a more stable strain free structure temperature pore water time and other variables affecting these changes act only to promote reaction rates to the defect free stable structures

halogen bearing minerals in syenites and high grade marbles of dronning maud land antarctica monitors of fluid compositional changes during late magmatic fluid rock interaction processes meta sedimentary rocks including marbles and calcsilicates in central dronning maud land cdml in east antarctica experienced a pan african granulite facies metamorphism with peak metamorphic conditions around 830 20 c at 6 8 0 5 kbar which was accompanied by the post kinematic intrusion of huge amounts of syenitic charnockitic magmas at 4 5 0 7 kbar the marbles and calcsilicates may represent meta evaporites as indicated by the occurrence of metamorphic gypsum anhydrite and cl rich scapolite that formed in the presence of saline fluids with x nacl in the range 0 15 0 27 the marbles and calcsilicates bear biotite tremolite and or hornblende and humite group minerals clinohumite chondrodite and humite which are inferred to have crystallized at about 650 c and 4 5 kbar the syenitic intrusives contain late magmatic biotite and amphibole formed between 750 and 800 c as well as relictic magmatic fayalite orthopyroxene and clinopyroxene two syenite and two calcsilicate samples contain fluorite corona textures in the marbles and calcsilicates suggest very low fluid rock ratios during the formation of the retrograde 650 c assemblages biotite in all but two syenite samples crystallized at log f h 2 o f hf ratios of 2 9 0 4 while in the calcsilicates both biotite and humite group minerals indicate generally higher log f h 2 o f hf values of up to 5 2 a few samples though overlap with the syenite values log f h 2 o f hcl derived from biotite covers the range 0 5 2 6 in all rock types within a single sample the calculated values for both parameters vary typically by 0 1 to 0 8 log units water and halogen acid fugacities calculated from biotite olivine orthopyroxene feldspar quartz equilibria and the above fugacity ratios are 1510 2790 bars for h2o 1 3 5 3 bars for hf and 7 600 bars for hcl the results are interpreted to reflect the reaction of relatively homogeneous magmatic fluids in terms of log f h 2 o f hf derived from the late magmatic stages of the syenites with both earlier crystallized still hotter parts of the syenites and with adjacent country rocks during down temperature fluid flow fluorine is successively removed from the fluid and incorporated into f bearing minerals close to the syenite into metamorphic fluorite in the course of this process log f h 2 o f hf increases significantly chlorine preferably partitions into the fluid and hence log f h 2 o f hcl does not change markedly during fluid rock interaction

shear velocity structure in the aegean area obtained by inversion of rayleigh waves summary the purpose of this work is to derive a 3 d tomographic image of the shear wave velocity structure of the crust uppermost mantle in the aegean area using the group velocities of rayleigh wave fundamental mode the database consists of 185 regional earthquakes recorded at broad band stations that were installed for a period of 6 month in the aegean area within the framework of a large scale experiment in a previous work karagianni et al 2002 an averaged group velocity has been determined using the method of frequency time analysis ftan for each epicentre station ray path and the data were used in order to determine the local group velocities for different periods over the area covered by the seismic ray paths taking into account additional resolution results obtained for the local group velocities a grid of 0 5 was adopted for the aegean area and a local dispersion curve was defined for each gridpoint more than 80 local dispersion curves were finally inverted using a non linear inversion approach deriving the corresponding 1 d shear velocity models the interpolation of these models resulted in a 3 d s wave tomographic image of the crust and uppermost mantle in the broader aegean area as expected as a result of the complex tectonic setting of the aegean area strong lateral variations of the s wave velocities of the crust and uppermost mantle of the studied area are found in the southern aegean sea as well as in a large part of the central aegean sea a thin crust of approximately 20 22 km is observed whereas the remaining aegean sea area exhibits a crustal thickness less than 28 30 km on the contrary a crustal thickness of 40 46 km is observed in western greece along the hellenides mountain range whereas in the eastern continental greece the crust has a typical thickness of approximately 30 34 km for shallow depths 10 km low s wave velocities are observed under the sedimentary basins of the north aegean sea the gulf of thermaikos axios basin and western greece at depths ranging from 10 to 20 km low s wave velocities are mainly found in western greece under peloponnesus as well as in rhodes this low velocity zone seems to extend along the hellenic arc and can be correlated to the hellenides mountain range and the alpine orogenesis in agreement with previous p wave tomographic results in the southern aegean sea very low s wave velocities 3 6 4 0 km s 1 are observed at depths of approximately 30 40 km just below the moho discontinuity while in the rest of the inner aegean sea and continental greece the uppermost mantle is characterized by velocities around 4 3 4 4 km s 1 this low velocity zone in the southern aegean sea can be associated with the high temperatures and the presence of significant percentage partial melt in the mantle wedge of the southern aegean subduction zone in agreement with previous studies

seismic source parameter relations for earthquakes in greece a data set of nineteen mainly shallow moderate to large earthquakes which occurred in the aegean and the surrounding area has been used to derive empirical relations for kinematic fault parameters thus the relations between seismic momentm 0 and magnitudem s andm b and betweenm 0 andm s and fault dimensionss andl have been determined from these relations and theoretical ones it was deduced that earthquakes in the aegean and the surrounding events chiefly interplate are characterized by low average stress drop values values of ranging from 1 to 30 bar are consistent with the data it was also found that in general terms most of the data obey the geometrical similarity conditionl 2w wherel is the fault length measured along the strike andw is its width measured along the dip for strike slip faults however the conditionl 4w seems to hold

interstratification of graphene like carbon layers within black talc from southeastern china implications to sedimentary talc formation large deposits of unusual black talc interstratified with dolostone layers of the late neoproterozoic dengying formation were discovered in guangfeng county jiangxi province southeastern china the black talc ore exhibits primarily oolitic structures and consists mainly of talc 30 70 wt dolomite and quartz with trace amounts of pyrite and apatite the ooids are composed of nearly pure black talc crystals most of which consist of ultrafine nano plates the black talc contains small amounts of carbon which causes the black coloring raman spectra and x ray photoelectron spectroscopy xps results indicate structural disorder and chemical impurities within bonds e g sp 3 hybridized carbon and c o bonds in the carbonaceous material instead of perfectly structured graphite or graphene isolated graphene like carbon interlayers are present in the talc nano crystals as shown by z contrast transmission electron microscope tem imaging based on previous studies on mg silicate precipitation from surface water we propose a sedimentary formation mechanism for the black talc in which tetrahedral octahedral tetrahedral t o t layers of mg silicates 1 2 unit cells thick co precipitated with abundant organic matter derived from microorganisms thriving in locally al depleted sea water with high concentrations of mg 2 and sio 2 aq in a shallow marine or lagoonal environment the involvement of organic matter may have facilitated the precipitation of mg silicate further diagenesis and re crystalliztion of the biomass coated precursor resulted in the formation of graphene like layers between neighboring talc nano crystals with same orientation

direct evidence for organic carbon preservation as clay organic nanocomposites in a devonian black shale from deposition to diagenesis abstract the burial of marine sourced organic carbon oc in continental margin sediments is most commonly linked to oceanographic regulation of bottom water oxygenation anoxia and or biological productivity here we show an additional influence in the devonian woodford shale in which oc occurs as nanometer intercalations with specific phyllosilicate minerals mixed layer illite smectite that we term organo mineral nanocomposites high resolution transmission electron microscopic hrtem images provide direct evidence of this nano scale relationship while discrete micron scale organic particles such as tasmanites algal cysts are present in some lamina a strong relation between total organic carbon toc and mineral surface area msa over a range of 15 toc indicate that the dominant association of organic carbon is with mineral surfaces and not as discrete pelagic grains consistent with hrtem images of nanocomposites where periods of oxygenation are indicated by bioturbation this relationship is modified by a shift to lower oc loading on mineral surfaces and reduced msa variability likely resulting from biological mixing and homogenization of the sediment oxidative burn down of oc and or stripping of oc from minerals in animal guts the toc msa relationship extends across a range of burial depths and thermal maturities into the oil window and persists through partial illitization where illitization occurs the loss of mineral surface area associated with the collapse of smectite interlayer space results in a systematic increase in toc msa and reorganization of organic carbon and clays into nano scale aggregates while the woodford shale is representative of black shale deposits commonly thought to record heightened marine productivity and or anoxia our results point to the importance of high surface area clay minerals for oc enrichment given that the vast majority of these clay minerals are formed in soils before being transported to continental margin settings their mineralogy and attendant preservative potential is primarily a function of continental climate and provenance making these deposits a sensitive recorder of land as well as oceanographic change

structural evolution of a quartz sillimanite vein and nodule complex in a late to post tectonic leucogranite western adirondack highlands new york abstract quartz sillimanite veins and nodules within the carapace of a late to post tectonic leucogranite crosscut one another as well as calcsilicate schlieren these relationships document a fracture related and hydrothermal origin of the vein and nodule complex two dominant orientations n50e n20e are observed with the former being the oldest and most deformed both of these sets have undergone deformation including boudinage of veins to produce nodules zircon geochronology fixes the emplacement age of the leucogranite at 1035 1 3 8 ma and late crosscutting pegmatites at 1034 10 ma hence the vein nodule complex must fall within this interval late dikes of leucogranite truncate the complex and document the continued presence of magma during vein nodule formation anisotropy of magnetic susceptibility ams in the leucogranite carapace reveals an approximately horizontal flow direction within a plane striking n49e and dipping moderately to the northwest in this regime quartz sillimanite veins formed initially as tension fractures in subvertical nne orientations either as a result of high fluid pressures or rapid sinistral shear along the n50e contact progressive sinistral shear rotated the veins counterclockwise causing buckling followed by boudinage and rotation of fragments into near parallelism with the n50e contact strain was accommodated by slip between crystals and melt migration with an estimated melt fraction of at least 30 multiple episodes of fracturing and vein formation appear to have occurred final deformation of the carapace and the vein nodule complex is envisioned as a flattening against the contact perhaps as a result of pluton inflation melt was still present after this event as evidenced by post vein granite and pegmatite dikes commonly with sinistral shear along the dike margin

carbonaceous material in pelitic schists of the sanbagawa metamorphic belt in central shikoku japan abstract carbonaceous material in pelitic schists of the sanbagawa metamorphic belt in central shikoku japan was separated from the host rocks and its x ray diffraction and chemical composition were studied its crystal structure and chemistry change continously with increasing metamorphic grade and approach those of well ordered graphite near the biotite isograd as graphitization is a rate process the temperature of complete graphitization differs from one metamorphic terrain to another as a function of the duration of metamorphism in an individual metamorphic terraan however the degree of graphitization is a useful indicator of relative metamorphic temperature in lower grade rocks

graphitization of organic matter and fluid deposited graphite in palaeoproterozoic birimian black shales of the kaya goren greenstone belt burkina faso west africa palaeoproterozoic black shales form an essential part of the birimian volcanosedimentary belt in burkina faso west africa the mean rmax values and the atomic h c values of the bulk carbonaceous matter bcm together with rock structures and mineral assemblages indicate that these carbon rich rocks were metamorphosed to sub greenschist and low grade greenschist facies x ray diffraction reveals that the 002 graphite peak width in half maximum fwhm ranges from 0 43 to 0 71 2 in sub greenschist facies and from 0 27 to 0 41 2 in greenschist facies rocks but the d 002 values in both groups of rocks are approximately the same 3 35 a the bcm of individual samples is composed of particles with very variable shape reflectance and raman spectra type i particles that predominate in sub greenschist facies are fine grained irregular or elongate bodies 1 to 3 m in size their maximum reflectance rmax ranges between 2 5 and 8 2 and raman parameters r1 and r2 range from 0 5 to 1 4 and 0 5 to 0 8 respectively type ii particles are lath shaped up to 40 m large bodies commonly arranged parallel to white mica flakes the number of these particles increases from sub greenschist to greenschist facies maximum reflectance varies between 6 and 11 2 and r1 and r2 raman parameters range from 0 05 to 0 7 and from 0 1 to 0 5 respectively type iii particles occur in hydrothermally altered and sheared rocks these are nodular aggregates composed of grains up to 10 m in size this type of particles has very high reflectance rmax 11 15 and its raman spectra indicate a very high degree of structural ordering corresponding to well ordered graphite type i particles represent original organic matter in the metasediments type ii particles are believed to have been formed either in situ by solid state transformation of type i particles or by crystallization from metamorphic fluids gradual graphitization of the type i organic particles and the growth of lath shaped type ii particles from a fluid phase is assumed to have taken place under the peak metamorphic conditions associated with the burial of birimian sediments during thrust tectonism progressive tectonic accretion and crustal thickening during the d1 event of the eburnean orogeny the growth of equant high reflectance postkinematic nodular aggregates of type iii particles is ascribed to the reduction of co2 rich fluids during a hydrothermal event associated with late eburnean d2 exhumation and strike slip movements type i carbonaceous particles were only slightly affected by high temperature low pressure contact metamorphism during intrusion of late eburnean magmatic bodies whereas formation of type ii or iii particles was not recorded in contact metamorphosed rocks at all

seismic faults in the aegean area abstract reliable fault plane solutions of shallow earthquakes and information on surface fault traces in combination with other seismic geomorphological and geological information have been used to determine the orientation and other properties of the seismic faults in the aegean and surrounding area thrust faults having an about nw se strike occur in the outer seismic zone along western albania westernmost part of mainland of greece ionian sea south of crete south of rhodes the inner part of the area is dominated by strike slip and normal faulting strike slip with an about ne sw slip direction occurs in the inner part of the hellenic arc along the line peloponnesus cyclades dodecanese southwest turkey as well as along a zone which is associated with the northern aegean trough and the northwesternmost part of anatolia all other regions in the inner part of the area are characterized by normal faulting the slip direction of the normal faults has an about sw ne direction in crete n38 e and an about e w direction n81 e in a zone which trends n s in eastern albania and its extension to western mainland of greece in all other regions central greece southern yugoslavia and bulgaria western turkey the slip of the normal faults has an about n s direction

mineralogy and mineral chemistry of detrital heavy minerals from the rhine river in germany as evidence to their provenance sedimentary and depositional history focus on platinum group minerals and remarks on cassiterite columbite group minerals and uraninite in the course of studying the gold bearing heavy mineral spectrum of sediments from the upper rhine river a distinct suite of detrital grains comprising platinum group minerals pgm cassiterite columbite group minerals and uraninite was identified and investigated using conventional and modern analytical methods this study aimed to characterize the selected mineral groups mineralogically and geochemically in order to identify possible source areas and to reconstruct different aspects of the complex sedimentary history of the rhine river sediments the pgm assemblage is dominated by grains of ru os ir alloys 70 followed by pt fe alloys sperrylite and rare other pgm accordingly this pgm assemblage represents highly mature physically and chemically extremely resistant compounds which may have experienced and survived repeated reworking during their sedimentary history pt fe alloys and sperrylite may originate from various sources however the predominant ru os ir alloy grains point to an origin from ophiolite sequences of unknown age but likely pre alpine variscan or older the exact locations of the primary sources and the complex prolonged sedimentary history of the detrital pgm with possibly multiple intermittent storages remain unknown detrital cassiterite grains were dated by the u pb method using la icp ms the age dates of cassiterite largely overlap with zircon age distributions by peaking distinctly at ca 325 ma majority of ages thereby implying a predominantly variscan age of the cassiterite grains and possible derivation from mineralization in the black forest area columbite group minerals are dominantly tapiolite originating from pegmatites rare uraninite grains attest that this mineral experienced rapid erosion transport and deposition in a reducing environment

raman observations on individual interplanetary dust particles abstract this paper reports the first raman study of a representative set of interplanetary dust particles idps belonging to different infrared spectral classes six different groups of raman spectra can be discerned among the 20 idps studied all particles except the four belonging to group 6 exhibit the raman signature of poorly crystallized carbonaceous material the degree of disorder of this material as evidenced by the width and relative strength of the two first order raman bands at 1360 relative cm 1 and 1600 relative cm 1 varies among particles from different spectral groups increasing from group 1 to group 5 the most ordered carbonaceous material with an estimated upper crystallite size limit of 60a group 1 is found in particles that tend to show deuterium depletions and that have infrared spectra characteristic of olivines raman spectra of particles belonging to groups 2 3 and 4 none of which have ftir spectra characteristic of olivines show clear evidence for the presence of carbonaceous material although the degree of order is noticeably less than for carbons in group 1 particles all seven particles with documented deuterium enrichments 1 2 fall into these three intermediate raman groups this relationship of the hydrogen isotopic compositions with the raman data suggests different carbonaceous carrier phases for deuterium depletions and enrichments particles from raman groups 5 and 6 whose spectra show little or no evidence for the presence of carbonaceous material show deuterium abundances within the range of terrestrial rocks in general there is no obvious relationship between raman groups and infrared classes which are based on the 10 m absorption band due to silicates in part this is due to the fact that no raman bands for silicates are seen although silicates are known to be present from infrared and analytical electron microscopic measurements the lack of silicate bands indicates that the silicate grains are coated with and or imbedded in a carbonaceous material which is presumably the reason that the particles look black in the visible several particles also show broad visible laser induced photoluminescence which is also probably produced by a carbonaceous component

spatial variations in temperature and composition of greisen forming fluids an example from the variscan triberg granite complex germany tin granites that host greisens have been extensively studied but surprisingly little work has been carried out on the properties of the fluids during greisen formation in the triberg granite complex southwestern germany it has been possible to reconstruct part of the chemical and physical evolution of these greisen forming fluids this granite complex contains an area of about 30 km 2 with cassiterite bearing greisen assemblages and beryl bearing pegmatites that have been locally affected by the greisen forming fluids the cassiterite occurs in narrow veins and in miarolitic cavities and is disseminated in parts of the granite in places beryl bearing pegmatites which are hosted by the same granite unit and texturally predate the greisen interacted with the greisen forming fluids production of secondary beryl albite phenakite bertrandite and kaolinite is associated with the replacement of the primary beryl in the pegmatites the systematic variation of mineral assemblages in different parts of the leucogranitic part of the triberg granite complex indicated temperature and chemical gradients in the fluids calculations of mineral stabilities and fluid inclusion studies on cassiterite and beryl support the existence of the gradients that were inferred from the field observations estimated pressure and salinity were nearly constant pressure was estimated to be 1 500 bars and the measured salinity was 4 to 5 wt percent nacl equiv from the interior to the margin of the study area the temperature decreased from 550 degrees to about 250 degrees c and the concentration of hydrofluoric acid hf in the fluid decreased from 0 06 to 0 002 moles l the best explanation of the greisen formation is a model that postulates a source of the mineralizing fluids in the center of the mineralized area these fluids may have been released from a fluid trap in a cupolalike structure and may have penetrated radially outward into the cooled granite where they formed the greisen assemblages affected beryllium pegmatites and caused thermal and chemical gradients

the role of carbonaceous indicator slates in the genesis of lode gold mineralization in the western lachlan orogen victoria southeastern australia indicator slates have long been considered to represent a useful exploration guide for turbidite hosted mesothermal lode gold mineralization in central victoria this assumption has been based on an apparent close spatial relationship between high gold grades and the proximity of thin commonly pyritic and carbon rich marker units detailed studies in a number of gold deposits throughout central victoria however reveal that highest gold grades do not necessarily coincide with the presence of carbonaceous units in many places where gold mineralization is associated with carbon rich matter the high c accumulations are the result of epigenetic remobilization during hydrothermal alteration and ore genesis petrographic geochemical and stable isotope c o s investigations into the origin and nature of the carbonaceous matter mainly amorphous bitumens and pyrobitumen of organic origin with biological fragments and rare graphite of both detrital and metamorphic origin demonstrate that black shales within the cambro ordovician succession in central victoria lacked the vital constituents to provide 1 a primary sink for precious metals and 2 whereas the presence of carbonaceous matter was likely to affect the evolution of epigenetic hydrothermal fluids and locally may have facilitated gold enrichment carbon rich sedimentary rocks were not crucial for ore genesis on the deposit scale instead the size of the hydrothermal cell physicochemical conditions of the ascending fluids and dynamic fault valve behavior played far more significant roles in controlling gold precipitation the importance of these processes has implications for exploration targeting sediment hosted lode and disseminated style gold mineralization in the western lachlan orogen and in slate belt provinces elsewhere

properties of the 1979 monte negro southwest yugoslavia seismic sequence focal properties of the monte negro earthquake 15 april 1979 m 7 1 and its seismic sequence foreshocks and aftershocks which occurred near the southwestern coast of yugoslavia are investigated fault plane solutions of the main shock and its largest aftershock 24 may 1979 m 6 3 and the spatial distribution of the shocks of this sequence show that the seismic fault strikes about southeast northwest parallel to the coast and dips northeast towards the continent it is a strike slip left lateral fault with a considerable thrust component its length is 95 km and its width 12 km an aseismic belt which separated the aftershock foci into two groups the northwestern and southeastern is interpreted as a section of the fault that slipped smoothly during the main shock the aftershock foci were barriers where stress had been induced one of these barriers broke later and produced the largest aftershock of 24 may

fault structure and related basins of the north aegean sea and its surroundings 1 fault structure and basin evolution in the northern aegean sea and its surroundings have been investigated using bathymetry available onshore and offshore seismic profiles onshore fault patterns from ne greece nw turkey three islands in the aegean sea surface ruptures associated with the 1978 thessaloniki earthquakes gps measurements from north aegean islands and a number of earthquake focal plane solutions and historic seismicity bathymetric and isopach data show that the north aegean trough can be divided into the sporades basin and the saros trough post miocene sediment thickness differences in these basins offset of distinct horizons and frequent seismicity along basin bounding faults indicate that sediment accumulation in the area is fault controlled offshore seismic profiles show that the basin bounding faults are dominantly characterized by apparent normal components as well as strike slip components inferred from typical fault zone profiles additional evidence for existence of strike slip faulting comes from earthquake focal plane solutions we refined the pattern and kinematics of the faults controlling the basins and classified them into two major groups the faults in the first group trend ne sw and ene wsw and are here interpreted to be dominantly right lateral strike slip with normal or reverse components these faults accommodate a similar amount of deformation like the ganos fault and thus represent the westernmost extension of the north anatolian fault zone the faults in the second group trend nw se and are dominantly normal faults with an occasional left lateral component these faults are believed to manifest the termination of the north anatolian fault zone because of the segmentation of the right lateral strike slip faults and the preexisting ne trending tectonic grain the basins are compartmentalized into smaller depocenters basins are orientated with their long axes either parallel to the ne sw to ene wsw trending echelon strike slip faults or in the zone north of the strike slip faults parallel to the nw se trending normal faults the interpretations regarding the kinematics of the faults are consistent with the data compiled from the islands near the faults and from the land in ne greece and nw turkey the northern aegean basins and their spatial relationships to the fault architecture representing the diffused termination of the north anatolian fault system are consistent with the mechanical principles of the strike slip tectonics

coarse muscovite veins and alteration in porphyry systems abstract coarse muscovite veins and alteration occur in porphyry copper and porphyry molybdenum copper systems within the laramide arc in arizona as well as at the yerington district in nevada this work describes coarse muscovite in veins and altered wall rock in porphyry systems in this region and documents mineral assemblages mineral compositions spatial and temporal relationships and hydrogen isotopic compositions coarse hydrothermal muscovite is documented in the roots of porphyry cu mo systems as well as in and above the ore bodies in porphyry mo cu systems and it is compared to coarse hydrothermal muscovite greisen in lode sn w mo systems basin and range extension has exposed coarse hydrothermal muscovite in several laramide and jurassic porphyry cu mo systems at paleodepths of 3 to 12 km miami inspiration sierrita esperanza copper basin crown king granite mountain roots of the ray porphyry system gunnison texas canyon stock grayback kelvin riverside district sycamore canyon the new cornelia mine ajo district and two systems in the yerington district muscovite is the dominant mica in these coarse muscovite veins and associated alteration with common k feldspar and albite an00 06 common accessory hematite rutile pyrite and apatite and rare accessory chalcopyrite fluorite molybdenite wolframite and scheelite coarse hydrothermal muscovite yields d compositions that suggest formation from fluids that are dominantly magmatic hydrothermal in origin whole rock compositions of coarse hydrothermal muscovite show common gains in k and loss of ca na coarse muscovite veins and alteration in porphyry copper systems postdate mineralized potassic veins and form too deeply to overlap with shallower acidic forms of alteration sericitic advanced argillic variation in mineral assemblage mineral compositions and mineralization of coarse hydrothermal muscovite correlate with the composition of laramide stocks porphyry mo cu systems contain coarse muscovite alteration assemblages with the highest mineral diversity and trace element enrichment coarse muscovite veins and alteration in porphyry mo cu systems related to stocks ranging from quartz monzonite to granite in composition form at shallower paleodepths and occur within and above the associated orebodies in contrast coarse muscovite veins and alteration associated with subalkaline porphyry copper systems occur at deeper levels in some cases overlapping with the bottom of potassic alteration and the ore body but extending well into the roots of the system in the underlying granitoid cupola in these latter systems zones of coarse muscovite alteration typically are poorly mineralized and mineral assemblages are less varied these characteristics suggest that coarse muscovite forming fluids are predominately of magmatic hydrothermal origin and exsolved from late stage fractionated magmas of the larger pluton that sourced porphyry stocks and dikes responsible for porphyry copper mineralization in some instances however the exposed coarse muscovite alteration is associated with a petrologically unrelated commonly more felsic later intrusion rather than being related to late exsolution of fluid from the same crystallizing stock or batholith

kinematics and deformation of central and southwestern greece from historical triangulation data and implications for the active tectonics of the aegean abstract changes in the coordinates of 38 stations 32 of which were common to three historical triangulation surveys 1889 1905 1927 1930 and 1950 1970 in central greece were computed based on conventional adjustment techniques and the assumption of a nearly fixed baseline length some of the calculated coordinate changes are significant against the a posteriori network adjustment errors and are likely to indicate tectonic motions consistent with those deduced from geological and geophysical data and other geodetic studies comparison of the first survey network with gps data more explicitly the historical geodetic data confirm the rotational character of the deformation in the area but they show that the strain pattern is likely to have changed after 1930 between 1890 and 1930 strain was changing smoothly as if no strain discontinuities existed while the peloponnesus was under contraction from the northeast probably reflecting accommodation of strain from the arc significant left lateral shear in the gulf of corinth and n s extension in the whole of the study area were observed only after 1930 estimates of strain are consistent with those deduced from comparison of historical triangulation and gps data corrected for the scale error that exists in the terrestrial geodetic data in greece and estimates of strain from seismological data the change in the kinematic pattern after 1930 seems to be confirmed by changes in the shear strain computed directly from changes in observed angles between stations and from changes in the seismicity rates such changes although not unusual in the geological record are not easy to explain but may reflect elastic rebound effects in area with an extremely complicated tectonic fabric or hysteresis in the accommodation of e w compression from the arc by n s stretching

a microearthquake study in the gulf of patras region western greece and its seismotectonic interpretation summary the seismicity of the gulf of patras region was monitored from 1983 may to 1984 april by a six station microearthquake network with 30 km aperture over 650 events were located using the revised version of the hypo71 computer program for determining hypocentral locations of these a subset of 73 well located events was identified for detailed study analysis of these 73 events reveals a local pattern of seismicity with two main features firstly a gap in seismicity in the central and western parts of the gulf despite the local presence of active faulting affecting the seabed secondly a zone of high seismicity in the northeast part of the gulf where offshore seismic surveys reveal a zone of intense structural complexity a northeast dipping diffuse zone of seismicity extending to a depth of about 25 km has been identified in the northeastern corner of the gulf centred on the rio antirrio channel between the gulfs of patras and corinth it is postulated that the active faults in the central part of the gulf which are apparently aseismic are linked via a shallow decollement surface under the gulf to a deep wnw ese trending fault zone defining the southern margin of the corinth graben and extending westwards to trichonis lake the dipping zone of seismicity is related to the latter fault zone and aseismic faulting in the gulf of patras is attributed to the shallow surface of decollement into which the faults sole a transfer fault zone trending approximately ne sw is postulated to account for the offset of the corinth and patras grabens

a study of the 1980 summer seismic sequence in the magnesia region of central greece summary properties of the seismic sequence foreshocks and aftershocks of the 1980 july 9 m 6 5 earthquake in the magnesia region of central greece are investigated fault plane solutions of the three major shocks of the sequence distribution of epicentres geological data and field observations show that the seismic fault is a normal trending ene wsw and dipping sse evidence that its dip angle decreases with depth is presented the parameter b in the frequency magnitude relation was found equal to 0 84 for the foreshocks and equal to 1 28 for the aftershocks while the decay parameter p of the time distribution of the aftershock frequency was found equal to 0 72 the frequency of foreshocks which started on july 4 increased till july 6 but after that decreased till the occurrence of the main shock while their average magnitude decreased continuously between july 4 and 9 a striking similarity between the focal properties of shocks of this sequence and of shocks of two other sequences which occurred in 1978 and 1981 in the back arc aegean area is attributed to tensional forces acting in this area since the middle pleistocene

non pegmatitic deposits of beryllium mineralogy geology phase equilibria and origin non pegmatitic occurrences of be minerals constitute a diverse set of geologic environments of considerable mineralogical and petrological interest they currently provide the majority of the world s be ore and emeralds and they contain the greatest resource of these commodities of the approximately 100 be minerals known see chapter 1 by grew appendix a most occur in hydrothermal deposits or non pegmatitic igneous rocks where their distribution varies systematically with the setting and origin table 1 fig 1 view this table table 1 beryllium minerals in non pegmatitic deposits formulas use and occurrence 1 figure 1 chemography of the principal solid phases in the beo al2o3 sio2 h2o f2o 1 bash system with the projected positions of helvite group and alkali be silicates also shown are generalized fields for some of the major types natural of occurrences cf table 1 fig 4 see text for discussion beryllium minerals are best known from geologic systems associated with felsic magmatism they also occur in a variety of settings that lack evident igneous associations environments range from the surface to the deep crust and host rocks range from feldspathic to carbonate to ultramafic in composition genetically related igneous rocks are felsic and share low calcium and high f contents but are diverse in composition setting and origin compositions range from strongly peraluminous to peralkaline and can be silica undersaturated beryllium minerals also occur in metamorphic and basinal environments and are redistributed by surface processes table 2 summarizes the types and significance of major groups of occurrences by their lithologic associations figure 2 shows the global distribution of some important examples and regional belts for most types at least one example has been described in some detail and can be used to help evaluate general patterns however

raman spectrum of carbonaceous material a possible metamorphic grade indicator for low grade metamorphic rocks raman spectral analyses of carbonaceous material cm extracted from pelitic samples along two sections traversing the metamorphic belt of taiwan were carried out in the present study the results show similar spectral variations of cm with metamorphic grade as those documented in the literature however continuous sampling from zeolite facies through prehnite pumpellyite facies to greenschist facies metamorphic rocks in the present study does reveal some interesting features on the raman spectra of cm that were not noted before both the raman d disordered o ordered peak area i e integrated intensity ratio and the d o peak width i e full width at half maximum fwhm ratio of the cm decrease with progressive metamorphism but the most prominent change in the d o peak area ratio occurs in samples of lower greenschist facies metamorphic grade while the most significant decrease in the d o peak width ratio occurs in samples near the boundary of prehnite pumpellyite facies and greenschist facies this phenomenon is interpreted as a result of the decoupling of the changing rates of in plane crystallite size and degree of defects of cm with progressive metamorphism it is postulated that the raman spectrum of cm can serve as a metamorphic grade indicator to distinguish samples of prehnite pumpellyite facies metamorphic grade from those of greenschist facies metamorphic grade

the winter 1991 1992 earthquake sequence at cephalonia island western greece properties of the earthquake sequence of the 23 january 1992 5 8 ms earthquake in cephalonia island western greece are investigated the parameter b in the frequency magnitude relation is found equal to 1 084 while the decay parameter p of the time distribution of the aftershock sequence is found equal to 0 991 the principal parameters method is applied to the aftershock sequence and the average strikes of n156 e 20 and n61 e 10 were obtained denoting also very small dips the major strike which resulted from the aftershock epicentre distribution was nw se similar to miocene neogene basins on cephalonia island

focal mechanism solutions for albanian earthquakes for the years 1964 1988 abstract focal mechanism solutions for 175 albanian earthquakes of albania for the years 1964 1988 were obtained by using an interactive computer technique the results obtained are elaborated upon by applying fisherian statistical analysis to obtain parameters for the mean stress direction in five zones to explain the results a wedging model in the interaction zone between the adria microplate and albanian orogen is suggested

interstratification of carbonaceous material within illite we here report the first recognized natural occurrence of a clay mineral with interstratified carbonaceous material that in places approaches graphite in its structural ordering using high resolution transmission electron microscopy hrtem we found that carbonaceous material in an early stage of graphitization occurs in extremely thin 100 aa domains both between and interstratified within illite crystals this material could have been trapped during the growth of the illite or have been inherited from precursor clay minerals in the host sediments during diagenesis and metamorphism graphitization in low grade rocks involves complicated microstructural changes in the carbonaceous material as a result of its fine scale intergrowth with clay minerals in addition this study demonstrates that by utilizing ion milled specimens in situ structures and textures of fine grained carbonaceous samples can be investigated without the unavoidable disruption produced by crushing or grinding

coseismic crustal deformation on a fault zone defined by microseismicity in the pavliani area central greece summary pavliani is an area of high microseismicity in northern central greece there is no evidence in the historical record of large damaging earthquakes in this area since at least 600 bc we examine contemporary crustal deformation in this area using microearthquake data recorded during 1983 84 by the volos seismic network principally and to a lesser extent by the patras seismic network the microseismicity 1 4 6 ml defines an approximately vertical fault zone trending wsw ene of 55 km length and 25 km depth the fault plane solution for the 4 6 m earthquake shows a strike consistent with the trend of the microseismicity zone and an extension direction consistent with many large earthquakes in central greece associated with the extensional greater aegean spectra of the microearthquakes are estimated using p waves obtained by selective windowing designed to exclude other p phases from the coda seismic moments in the range 1 95 x 10 n m are obtained accompanied by estimates of seismotectonic source parameters including source radii average stress drop and average coseismic slip of prime utility is an excellent correlation found between seismic moment and magnitude and with coseismic slip this allows heterogeneity in the distribution of individual microearthquake source parameters to be mapped onto the vertical fault zone plane and the history of coseismic deformation for the whole seismicity observed during 1983 84 to be examined using cumulative slip and moment release rate peaks of high moment release rate occur in the east and centre of the fault zone that in the east is dominated by a few large moment release events that in the centre by a large number of small events both moment release rate peaks despite their different component seismicity are associated with high cumulative coseismic slip only the eastern peak is also associated with high stress drop it is also shallower and therefore any surficial interaction is less likely to be attenuated the surface projection of this peak is within 3 km of a mapped normal fault coincident with an alpine thrust front delineated by a major scarp of mesozoic limestone surface evidence of recent movement on this normal fault is only slight friable fault gouge is seen at a few localities displacement could not be determined because the limestone surfaces are deeply weathered and lack kinematic indicators however considering the whole fault zone as a cohesive entity and using a brune estimate of slip at the current moment release rate throughout the present extensional tectonic regime suggests a total vertical displacement of order 175 m similar to the elevation of the scarp

tectonic stages along a traverse cross cutting the rhodopian zone greece in a cross section along the rhodopian zone from the greece bulgarian border through the postalpine basins in the xanthi area to thasos island detailed structural mapping and collection of field data enable us to determine a sequence of tectonic stages that affected this area this allows us to propose a model of continental collision during the early eocene ne sw directed movements produced a southwest facing pile of crystalline nappes with internal deformation comprising nw and ne trending isoclinal folds and a ne sw trending stretching lineation after a short time interval nappe movements started again under brittle deformation conditions and produced composite thrust sheets wnw and nne trending chevron folds and thick cataclasite late erogenic uplift and extension caused the formation of nw and ne trending normal faults these faults bounded the oligocene flysch and molasse basins and provided pathways for voluminous magmatic suites this tectonic process was interrupted at the oligocene miocene boundary by a late orogenic compression reflected in nw open folds and dissolution cleavages subsequently differential uplift and subsidence associated with nw and ne trending normal faults has continued up to the present time from the early pliocene new fragmentation and thinning of the crust reflected in wnw listric faults and nne transfer faults has affected the southern parts of the rhodopian zone nappe forming movements are the result of a progressive collisional process involving a kimmerian microcontinent lying between the eurasia and apulia continents in the final stages of this collision uderplating processes led to regional uplift and extension additional extensional movements were related to the formation of the aegean back arc basin caused by the late cenozoic hellenic subduction zone