earthquake generated tsunamis in the mediterranean sea scenarios of potential threats to southern italy italian civil defense project development of new technologies for the protection of the italian territory from natural hazards funded by the italian ministry of university and research

first archaeomagnetic field intensity data from ethiopia africa 1615 12 ad abstract first archaeointensity determinations have been obtained from ethiopia seven bricks 34 specimens from the dabsan archaeological remains were subjected to archaeointensity determination by means of classical thellier thellier experiment including tests for magnetic anisotropy and magnetic cooling rate dependency the age of the dabsan palace is well controlled by historical information between 1603 when land grants were conceded to the jesuits and the catholicism was established as the official religion in ethiopia and the age of the palace foundation in 1626 27 successful archaeointensity determinations were obtained in 27 specimens from five individual bricks revealing an average field value of 33 5 1 1 t which is 11 26 lower than expected values from global geomagnetic models based on historical and archaeomagnetic data global models for 1615 ad predict a low in central southern africa related to past location of the present southern atlantic anomaly saa our results suggest that the field intensity in central africa may have been slightly lower than global model predictions this would indicate that the low could be probably more extended towards central eastern africa or more intense than previously considered further data from this region are especially welcome to delineate the evolution of the saa

karelian shungite an indication of 2 0 ga old metamorphosed oil shale and generation of petroleum geology lithology and geochemistry abstract the ca 2 0 ga old 600 m thick upper zaonezhskaya formation near lake onega nw russia contains unusually high concentrations of corg up to 98 averaging around 25 the formation contains an estimated 25 1010 tonnes of organic carbon accumulated within an area of 9000 km2 organic material is represented by shungite which forms a black dense amorphous or nanocrystalline mass consisting of c with traces of n o s and h autochthonous shungite occurs as disseminated organic material 0 1 50 corg which when mixed with migrated bitumen now pyrobitumen appears as coal like seams and lenses of semilustrous and semimat layer shungite rocks oil shales 50 75 corg the migrated bitumen originally petroleum represented by the lustrous vein and layer shungite conformably fills interbedding spaces or cross cutting joints and usually contains 80 98 corg the shungite bearing rocks of the upper zaonezhskaya formation represent one of the most richest accumulations of organic material reported from the palaeoproterozoic and one of the geologically earliest stages of petroleum generation the sediments of the zaonezhskaya formation were initially deposited in brackish water in a non euxinic lagoonal environment the high c s ratio 8 1000 with a zero intercept on the c s cross plot indicates that deposition occurred in sulphur poor water intensive synchronous volcanism may have contributed to both the enhanced delivery of nutrients and elevated sedimentation rate and eventually to the high degree of preservation of organic material the integrated data suggest that the organic material has a biogenic origin most likely algal or bacterial the organic material suffered complex catagenetic and metamorphic alteration which is reflected in 1 the four modal distribution of corg content with maxima at 5 30 65 and 95 2 highly variable 13 c org 45 to 17 3 bimodal distribution of 13 c org with maxima at 28 and 39 and 4 low h c ratios 0 005 0 2 abundant diagenetic carbonates associated with shungite rocks 13 c carb 5 to 26 and the presence of pyrite 34 s 22 to 31 reflects substantial loss of organic matter via bacterial reduction of sulphate during diagenesis the shungite rocks are characterised by a further substantial loss 50 of biologically produced organic material in the course of thermal maturation and by a depletion in 12 c 10 the isotopic composition of carbonate concretions does not indicate the involvement of fermentative diagenesis conservative estimates give 13corg of 34 as the best value of the initial biomass lustrous vein and layer shungite containing more than 80 corg are considered to be allochthonous migrated bitumen originally petroleum the semilustrous and semimat layer shungite rocks containing 55 75 corg represent oil shales with both migrated bitumen originally petroleum and autochthonous kerogen residues the oil source rocks were apparently hosted in the zaonezhskaya formation the generated oil has migrated both vertically and laterally with the highest concentration in cupola structures the locality at shunga represents the most significant volume of trapped petroleum from the study area

geoscience of ancient mediterranean harbours abstract although much has been written on the subject of ancient mediterranean harbours the relatively new area of harbour geoarchaeology remains dispersed in the geoscience and archaeological literature over a decade of research has amassed rich and varied datasets of anthropogenically forced coastal evolution with a remarkable number of between site analogies this new research field also shows the rich potential of geoscience to reconcile important archaeological questions no single publication however has yet drawn on these geological patterns to yield a detailed overview suitable for geoscientists and environmental archaeologists the aim of this review article is to 1 discuss how ancient harbours have come to be preserved in the geological record 2 expound the basic principles and palaeoenvironmental tools underpinning ancient harbour geoarchaeology 3 outline some of the most significant research advances made and 4 discuss a new chrono stratigraphic model applicable to harbour sequences

the search for fullerenes in rocks from the ries impact crater since their discovery fullerenes have been reported from various geological environments one group of these findings has been related to bolide impacts e g the sudbury crater and the k t and p t boundaries impact rocks of the ries crater germany including samples of suevites metamorphosed crystalline clasts and glass bombs have been collected in the otting altebrg and seelbronn quarries no fullerenes in concentrations above 1 ppb have been found in analyzed samples laser desorption time of flight mass spectrometry ld tof ms confirmed the absence of fullerenes in the analyzed samples these results support the concept that the ries impactor was a stony meteorite

river terrace development by concurrent fluvial processes and climatic changes abstract along the usui river in central japan three well developed terrace levels are observed each terrace is subdivided into two segments a filltop terrace along the upper reach and a strath terrace along the lower one three valley fillings with coarse gravel beds in the upper reach correspond to the last three glacial ages the positions of these valleysfills migrated upstream from the older terrace to the younger one to clarify the response of fluvial systems to climatic change terrace sediments were interpreted from the viewpoint of paleohydraulics using the grain diameter of terrace sediments paleo tractive forces were evaluated based on the correlation between tractive force and grain diameter of the sediment on the present river bed the valley filling was caused by the diminution in tractive force related to the decrease in heavy rain produced by typhoons during the glacial ages during the interglacial ages the reverse responses occurred due to the increased incidence of typhoons from another aspect of the development of river landforms the decrease in the liver channel gradient during the interglacial ages caused the transportational and or depositional area of coarse gravels to migrate upstream in the subsequent glacial ages

the role of organic matter in the metallogeny of the bohemian massif formations rich in organic matter occurred throughout most of the geologic history of the bohemian massif accumulation of organic matter was connected with basic submarine volcanic activity with transgressive sedimentary regimes and with limnic and paralic environments the largest carbon rich marine sediment accumulation occurred in late proterozoic and early paleozoic time in these periods substantial concentrations of trace elements and sulfur accumulated in black claystones where the metal associations were determined mostly by synchronous volcanicity in spite of the substantial amount of accumulated trace elements only subeconomic concentrations of pyrite pyrrhotite and u v sb au mineralizations were formed in association with proterozoic stromatolites subsequently cadomian and variscan metamorphic processes caused substantial remobilization of metals and sulfur in black claystones and produced disseminated gold and uranium deposits during the emplacement of postkinematic variscan granitoids organic matter and some metals were leached from the surrounding low metamorphic carbon rich sediments by hydrothermal solutions of deep crustal origin a typical feature of these deposits is the presence of isotopically light bitumens delta 13 c pdb 40 8 to 56 5ppm and the biological tracers phytane and pristane indicating a biogenic origin as a reducing agent organic carbon graphite controlled the localization of variscan hydrothermal uranium mineralization which occurs in graphitized shear zones in the highly metamorphosed basement of the bohemian massif the crystallinity of the graphitized organic matter decreases sharply in these zones probably due to hydrothermal decomposition of the graphite lattice the low crystallinity of graphite and anomalously light isotopic composition of the hydrothermal carbonates in this type of deposit delta 13 c pdb 6 to ppm indicate that graphitized organic matter was involved in the reduction of uranium bearing hydrothermal solutions during the formation of sandstone type uranium deposits in the carbon rich platform sediments of the bohemian massif the organic matter of host rocks became oxidized by the action of oxygen dissolved in ore bearing solutions this process gave rise to organic polymers similar to humic acids which reacted with uo super 2 2 to form insoluble uranium organic compounds

hydrothermal petroleum genesis migration and deposition in guaymas basin gulf of california hydrothermal activity and seabed mounds have been explored in guaymas basin by the deep sea drilling project dsdp piston coring dredging and diving with the deep submersible research vessel dsrv alvin sedimentary organic matter derived primarily from immature degraded microbial detritus is easily converted to petroleum under the hydrothermal regime these petroleums are mature and migrate in the fluids and by diffusion to the seabed the fluid migration is aided by near critical aqueous solution and supercritical carbon dioxide and hydrocarbons petroleum compositions vary from condensates to naphthenic to waxy all with significant amounts of asphaltenes and hydrothermal products such as olefins and toxic polynuclear aromatic hydrocarbons pah the heavy ends condense at the seabed depositing mainly as a cement with the sulfides and other minerals and to a lesser extent as entrapped oil and crystalline wax in vugs and conduits of the mounds the pah are high temperature resynthesis aromatiza

occurrence of natural fullerenes in low grade metamorphosed proterozoic shungite from karelia russia abstract we report on the occurrence of fullerenes in proterozoic shungite 2 ga from the shungite mine kondopoga karelia russia 62 12 n 34 17 e the presence of fullerenes has been confirmed by mass spectrometry with peaks at 360 and 720 amu atomic mass unit powder x ray diffraction showing ten diffraction peaks corresponding to the fullerite structure with a 1 4201 5 nm and 13 c nuclear magnetic resonance nmr spectroscopic studies showing a peak at 143 2 ppm in the kondopoga shungite mine fullerenes occur in silty shales that have experienced greenshist facies metamorphism

floodplain occupation and landscape modification in early rome abstract the site of rome in central italy provided many opportunities for the development of a city access to natural resources defensible terrain a ford in the tiber river among others in addition to these advantages the environment and landscape also presented numerous challenges to early inhabitants this ecological dichotomy is especially observable in the forum boarium a region situated in the tiber s floodplain at the base of the capitoline and palatine hills by the archaic period 7th 6th centuries bce this vital gateway for trade and communication was operating as a river port equipped with a harbor temple periodic flooding of the tiber river however consistently jeopardized these commercial and cult pursuits in the forum boarium as a result this region became the focus of early endeavors at landscape modification which helped to protect and facilitate the growth of urban infrastructure in the floodplain in order to explore geoarchaeological conditions in the floodplain a multi disciplinary research project was undertaken in the forum boarium between 2013 and 2015 this paper presents preliminary results from this recent investigation including evidence on the natural topography of the river valley floods and sedimentation as well as building techniques in a flood prone region in archaic and early republican rome it is argued that in response to varied and prolonged environmental stress landscape modification and continuous management became important prerequisites to rome s urbanization process in this way ecological pressures directly influenced the development of the city s built landscape this research not only represents a significant step towards a paleoenvironmental reconstruction of early rome but also demonstrates the advantages of coring survey in urban areas where access to deeply buried archaeological and geological stratigraphy is restricted

origins of fullerenes in rocks this article is a technical comment and author response to the the discovery of naturally occuring fullerenes in shunga rock samples the commenting researchers did not find detectable amounts of fullerenes in a variety of carbon rich rocks they hypothesize that the fullerenes found in the shunga sample were probably a localized event the original researchers buseck and tsipursky provide a rebuttal with further comments including parallels to other minerological occurences all agreed that more data are needed 10 refs

testing for fullerenes in geologic materials oklo carbonaceous substances karelian shungites sudbury black tuff comment and reply reply buseck et al s 1992 1 discovery of fullerenes in fractures in a shungite sample enclosed in diabase from russian karelia has been followed by several substantiating reports see buseck 2002 2 p 785 as well as by conflicting reports e g ebbesen et al 1995 3 mossman et al

multiple generations of carbonaceous material deposited in apex chert by basin scale pervasive hydrothermal fluid flow abstract the pilbara craton in western australia contains the best preserved and most complete record of archean rocks in the world as such they are some of the most studied rocks in the world paleontologists isotopic geochemists geologists and geobiologists have all investigated these rocks for clues about the early biosphere and atmosphere here we show using high resolution transmission electron microscopy that the carbonaceous material found in the apex chert and potentially in other associated units was formed by multiple processes such as abiotic catalytic synthesis and or biological synthesis we use these data as well as the geological history of the craton to demonstrate that when the rocks of the pilbara craton experienced a high degree of post depositional hydrothermal alteration carbonaceous material could have been remobilized and redeposited as the carbonaceous material within the apex chert samples was formed over nearly a billion years bulk chemistry even at the micron level will be unable to unambiguously delineate the presence of life in these ancient rocks although nanoscale observations may provide a way forward in the search for ancient life

an occurrence of coked bitumen raton formation purgatoire river valley colorado u s a abstract numerous examples of coke produced by igneous intrusion into coal have been reported in the spanish peaks region of south central colorado however in a recent study of an intruded section of the raton formation upper cretaceous paleocene along the purgatoire river near medina plaza co coked bitumen has been observed this material occurs in fingers hexagonally jointed bodies in a shaley xenolith within a lamprophyre sill and in carbonaceous type iii shale directly below the sill the coke fingers are characterized by a remarkable flow mosaic texture high vitrinite coke reflectance average random reflectance between 8 and 9 but with maximum readings around 14 15 high anisotropy abundant devolatilization vacuoles and an absence of inertinite inclusions within the underlying shales the coked bitumen occurs as pore void and fracture linings and fillings geochemically the coke in the fingers has low s1 and s2 values these observations suggest that the coke found in this study was not formed by the direct coking of coal but from a mobile phase bitumen or pitch that was subsequently coked by the intrusion this bitumen was either derived from the abundant coal within the section above the sill or from the organic matter contained within the type iii carbonaceous shales or both unaltered type iii shale sampled at this site has a hi of 350 mg hc g toc suggesting some albeit limited capacity to generate petroleum we suggest that bitumen was generated prior to or during the time of intrusion and was subsequently coked by the high temperatures of the emplaced sill as the bitumen pooled adjacent to the sill rapid heating led to the development of mesophase resulting in a highly anisotropic ribbon mosaic texture on cooling and vaporization of gases that subsequently condensed along pores vacuoles and fractures as pyrolytic carbon and spherulitic pyrolytic carbon bitumen within the underlying silty shales was also coked but to a lesser degree the texture of this coked bitumen looks very much like commercially produced petroleum coke this coked bitumen differs from other reports of coked bitumen in its mode of occurrence coke fingers in a xenolith ribbon mosaic structure and extremely high anisotropy and reflectance

organic geochemistry of precambrian shales and schists bohemian massif central europe abstract the composition and the structure of kerogens and subgraphitic materials from upper proteroic regionally metamorphosed black shales were investigated by different physico chemical method the isotopic composition of carbon changes with the intensity of the regional metamorphism kerogens from low grade metasediments have averaged 13 c values 35 kerogens from chlorite and biotite zones 31 samples display high diversity of primary sedimentary materialos details were obtained using transmission electron microscopy tem crystalline order improves with the intensity of the regional metamorophism turbostratic carbonacveous matter is described from low grade metasediments graphite occurs at the end of the biotite zone however both metallogenetic and contact metamorphic processes can be involved in some samples the second form of graphite has been identified probably of detrital origin inherited from some high grade metamorphic area existing at the time of sedimentation of primary rocks

testing for fullerenes in geologic materials oklo carbonaceous substances karelian shungites sudbury black tuff comment and reply the presence of low concentrations of fullerenes has been reported from numerous terrestrial and meteoritic sources buseck 2002 1 in a recent paper mossman et al 2003 2 present mass spectra of carbonaceous substances using laser desorption ionization ldi and high resolution electron

evidence for fullerenes in solid bitumen from pillow lavas of proterozoic age from mitov bohemian massif czech republic abstract andesitic pillow lavas containing biogenic solid bitumen sb are a constituent of a neoproterozoic volcanosedimentary sequence tepla barrandian unit bohemian massif in the mitov area of the czech republic a black shale formation that is crosscut by these andesitic basalts is 565 ma old carbon disulfide extracts of two powdered samples of sb contain 0 2 and 0 3 ppm of c 60 respectively as determined by high pressure liquid chromatography the peak assignment based on retention time is fully supported by high resolution electron ionization mass spectrometry ei ms no c 70 was detected nor was c 60 found in two other sb samples from this locality other investigated carbonaceous samples from bohemia coals and anthracites of upper paleozoic age and anthraxolite graphitoids and graphite of upper proterozoic age did not contain fullerenes at concentrations above the detection limit of 0 01 ppm the absence of c 60 in these samples was confirmed by ei ms the proposed mechanism of fullerene formation involves a primary algal phase generation of a hydrocarbonaceous mixture in the course of thermal evolution of the sedimentary series and their high temperature transformation related to the extrusion of basalt an important feature for fullerene conservation was the enclosure of fullerenes in sb with a structure similar to glasslike carbon where the fullerene was protected against oxidation

effect of anigneous intrusion on oil shale at rundle australia abstract elemental analyses x ray diffraction thermal and isotopic analyses gas chromatography mass spectrometry electron spin resonance nuclear magnetic resonance spectroscopy and demineralizing techniques have been used to evaluate the effect of a small igneous intrusion on rundle oil shale each set of results contributes to an overall appreciation of how in situ pyrolysis of a highly aliphatic kerogen occurs as in previous studies application of a range of methods gives a better understanding than any of the techniques on its own significant conclusions are as follows 1 the shale samples closest to the intrusion contain the least organic matter 2 a micro reservoir for expelled volatiles was identified 1 m below the intrusion 3 the hydrogen deficient carbonaceous residue remaining close to the intrusion produces no oil on further heating and 4 the major effect of the intrusive event was the in situ pyrolysis of the oil shale the severity of alteration decreasing with distance from the contact

eastern mediterranean tectonics and tsunami hazard inferred from the ad 365 earthquake historical accounts describe an earthquake and tsunami on 21 july ad 365 that destroyed cities and drowned thousands of people in coastal regions from the nile delta to modern day dubrovnik the location and tectonic setting of this earthquake have been uncertain until now here we present evidence from radiocarbon data and field observations that western crete was lifted above sea level by up to 10 m synchronously with the ad 365 earthquake the distribution of uplift combined with observations of present day seismicity suggest that this earthquake occurred not on the subduction interface beneath crete but on a fault dipping at about 30 within the overriding plate calculations of tsunami propagation show that the uplift of the sea floor associated with such an earthquake would have generated a damaging tsunami through much of the eastern mediterranean measurement of the present rate of crustal shortening near crete yields an estimate of 5 000 yr for the repeat time of tsunamigenic events on this single fault in western crete but if the same process takes place along the entire hellenic subduction zone such events may occur approximately once every 800 yr in the year ad 365 an earthquake and tsunami destroyed much of the eastern mediterranean coastal regions the distribution of uplift at the time suggests that the earthquake occurred on a fault within the overriding plate at the subduction zone beneath crete and not on the subduction interface itself

nanominerals and ultrafine particles in sublimates from the ruth mullins coal fire perry county eastern kentucky usa abstract mineral sublimates from the ruth mullins fire in abandoned underground and surface mines in the high volatile a bituminous middle pennsylvanian hazard no 7 coalbed perry county kentucky were examined by optical mineralogy x ray diffraction xrd and high resolution transmission electron microscopy hr tem optical examination revealed the presence of salammoniac and a fine unidentified fibrous mineral xrd also showed the presence of salammoniac along with trace amounts of quartz kaolinite and possibly phengite both cubic and dendritic salammoniac forms were observed with hr tem gypsum jarosite with cubic pseudomorphs after pyrite and fe minerals including cr bearing hematite in association with jarosite were observed with hr tem dehydration of jarosite can lead to the formation of less hydrous fe sulfates and hematite

geochemical markers of the cretaceous tertiary boundary event at brazos river texas usa the cretaceous tertiary boundary sites around the gulf of mexico are close to the chixculub impact site and are relatively well studied yet much remains to be learned about them therefore the first integrated study of carbon soot and fullerenes in a cretaceous tertiary boundary section was undertaken at the brazos 1 site on the brazos river in texas at the most complete section of end cretaceous and basal paleocene deposits on the texas segment of the gulf coast area up to 409 ppm of native sulfur so were serendipitously discovered in a spherule bearing unit of the br 1 section and lesser amounts were found in spherule bearing units of nearby brazos riverbed sections in a section on darting minnow creek the isotopic composition 33s 12 97 34s 24 89 and 36s 46 4 implies that this so cannot have come to earth by the impactor that formed the chicxulub crater but most likely was produced by sulfate reducing bacteria during a local transient bacterial bloom for which the sulfate was provided by caso4 bearing spherules carbon and soot were determined in twelve samples representing all units of br 1 from the cretaceous corsicana kemp formation to the tertiary kincaid formation a significant increase of c and soot contents up to 2 2 104 ppm and 1 4 104 ppm respectively occurs in a sandy bed at the top of the kt complex fullerenes were determined in fifty four samples from all units of the same br 1 section less than 1 ppb was reliably detected at the same sandy bed where the strongest ir anomaly of the section is known to occur it is suggested here that the chicxulub impact 65 ma ago ignited local wildfires that produced c soot and fullerene which settled onshore or near shore whence they were transported to the brazos site by coastal flooding and associated sediment laden water plumes moving offshore

thermal alteration of cretaceous black shale by diabase intrusions in the eastern atlantic ii effects on bitumen and kerogen abstract the thermal effects of three one major and two minor miocene diabase intrusions on cretaceous black shales from dsdp site 41 368 have been analyzed a concentration gradient was observed especially for the hydrocarbons decreasing towards the major intrusion and between the three sills the thermally altered samples in the proximity of and between the sills contained elemental sulfur and an excess of thermally derived pristane over phytane whereas the unaltered sediments contained no elemental sulfur and more phytane than pristane a maximum yield of the extractable hydrocarbons was observed at a depth of 7 m below the major sill two classes of molecular markers were present in this bitumen suite the first was sesqui di and triterpenoids and steranes which could be correlated with both terrigenous and autochthonous sources they were geologically mature and showed no significant changes due to the thermal stress the second class was found in the altered samples which contained only polynuclear aromatic hydrocarbons with low alkyl substitution and sulfur and oxygen heterocyclic aromatic compounds these compounds were derived from pyrolytic reactions during the thermal event kerogen was isolated from all of these samples but only traces of humic substances were present the h c n c 13 c 34 s and d all exhibit the expected effects of thermal stress the kerogen becomes more aromatized and richer in 13c 34s and d in the proximity of and between the sills maturation trends were also measured by the vitrinite reflectance and electron spin resonance where the thermal stress could be correlated with an elevated country rock temperature and an increased degree of aromaticity the effects of in situ thermal stress on the organic rich shales resulted in the generation and expulsion of petroliferous material from the vicinity of the sills

oily old ores evidence for hydrothermal petroleum generation in an archean volcanogenic massive sulfide deposit oil is formed in some modern seafloor vent systems after rapid thermal maturation of sedimentary organic matter by hydrothermal fluids although most of this petroleum escapes into the ocean some hydrocarbons may be trapped as fluid inclusions in hydrothermal precipitates or as bituminous residues in cavities however the geological record lacks evidence of this phenomenon which is unfortunate because it could be significant for understanding the history of petroleum genesis the processes of hydrothermal mineralization and perhaps the origin and early evolution of life from the pilbara craton of australia we report the discovery of pyrobitumen and oil in an early archean ca 3235 ma deep sea volcanogenic massive sulfide deposit the oil occurs in fluid inclusions within hydrothermal barite and pyrobitumen is intergrown with polymetallic sulfides petrographic textures show that the oil was emplaced and thermally altered coked before late stage sulfide mineralization the results demonstrate that subseafloor hydrothermal petroleum generation was active during the early archean possibly providing an energy and carbon source for a subsurface microbiota metabolizing hydrothermal sulfur species

environment human relationships in historical times the balance between urban development and natural forces at leptis magna libya abstract the relationships between human modification of the environment and natural events in the roman city of leptis magna unesco world heritage western libya are analyzed for the first time the history of leptis magna is tested against a geomorphological and stratigraphical reconstruction and radiocarbon dating historical and archaeological interpretations or analyses indicate the occurrence of different extreme natural events as the cause of the town s decline earthquakes flooding and tsunami geological and geomorphological surveys investigated the dynamics of the nearby wadi lebda a major dryland stream that forms the depositional and erosional systems of the settlement area alluvial phases were studied by applying traditional stratigraphic analyses of outcrops and hand cores additionally the mapped flights of inset terrace surfaces provided insights into the human modifications of the natural depositional erosional environment during historical times and the following alluvial phases affecting the leptis magna harbor the results integrate the archaeological knowledge by providing some independent chronological constraints and indicate that leptis magna history was tightly linked to the wadi lebda aware of the hazards related to devastating flooding the romans were able to cope with the threat posed by the wadi by performing engineering defensive hydraulic works around the town dam and artificial channels once the economic decay began and the society could no longer guarantee the ongoing maintenance of these structures the decline of the settlement started and the occurrence of destructive floods reclaimed the populated areas conversely the occurrence of a large earthquake 365 ce or of a tsunami that caused the disruption of the hydraulic systems and the infill of the harbor has been discarded as primary cause of the decline of leptis magna

an extraterrestrial impact at the permian triassic boundary becker et al 1 presented geochemical evidence that suggests that the largest mass extinction in earth history at the permian triassic boundary ptb 250 million years ago ma coincided with an extraterrestrial impact comparable in size to the one that likely caused the end cretaceous extinctions 65 ma 2 although becker et al analyzed material from sections in hungary japan and china the hungarian section yielded no extraterrestrial signature and their identification of the ptb in the japanese section is questioned in the accompanying comment by isozaki below thus only their analyses of the chinese section provide hitherto uncontested evidence for an impact at the boundary in the form of data on the abundance and composition of fullerenes in the boundary clay a volcanic ash layer called bed 25 at meishan china 3 although fullerenes may be purely terrestrial see e g 4 becker et al report that the fullerenes from the meishan ash carry extraterrestrial noble gases in the cage structure rich in 3 he and with distinctive 3 he 36 ar and 40 ar 36 ar ratios and that this signature therefore derived from a bolide impact here we report that we are able to detect fullerene hosted extraterrestrial 3 he neither in aliquots of the same meishan material analyzed by beckeret al nor any in samples of a second chinese ptb section and that we thus find no evidence for an impact

precambrian vein pyrobitumen evidence for petroleum generation and migration 2 ga ago abstract isotopic optical reflectance and chemical analyses of large pure samples of lower proterozoic vein pyrobitumens anthraxolite and thucholite of older reports collected from five widely separated localities in the great lakes region of the united states and canada suggest that in the lower proterozoic oil was generated from kerogen and migrated in much the same way as during the phanerozoic furthermore maturation and organic metamorphism followed the same successive stages that mark the generation and destruction of phanerozoic petroleum kerogens derived from algae and bacteria were deposited with subaqueous muds that ultimately became black shales or slates some of the kerogen however yielded petroleum which migrated into fractures and subsequently became pyrobitumen the 13c values average 32 6 pdb this value compares favorably with those from phanerozoic petroleum and asphaltites and is consistent with the proposition that the carbon isotopes were fractionated by biological activity reflectance values of the pyrobitumens range from 0 9 for elliot lake ontario to 9 5 for iron river michigan and h c ratios range from 0 6 for elliot lake to 0 1 for sudbury ontario when compared with the stages of petroleum maturation these values indicate maturation which ranges from the catagenesis stage through the metagenesis stage of petroleum generation and metamorphism

organic matter and the concentration of metals in precambrian stratiform deposits of the bohemian massif abstract organic matter is preserved in unmetamorphosed and low grade metamorphic pyrite and or mn bearing black shales pyrite mn stratiform ores cherts and siliceous stromatolites of proterozoic age in the barrandian area of the bohemian massif this organic matter consists mostly of kerogen with an isotopic composition and relative concentration of free radicals which depend on the metamorphic grade of the host rock 13 c pdb 30 7 to 36 9 nrel 0 161 to 0 132 enrichment of the kerogen in the light isotope of carbon a marked isotopic shift towards more positive 13c values with increasing metamorphic grade and the very low crystallinity of the incipient graphite lattice reflect the original aliphatic alicyclic character and algal origin of the kerogen its composition is similar to that of shungite chiefly aliphatic and alicyclic hydrocarbons were identified in the solvent extracts of these proterozoic rocks alkane patterns differ according to host rock type indicating their possible syngenetic origin other identifiable organic compounds amino acids carboxylic acids phenols and aromatic aldehydes are probably a result of later contamination the concentrations of u th v cr sb ag au zn and cu in pyrite and pyrite mn ores are relatively low in contrast stratiform concentrations of u v and chiefly au ag sb and zn are confined to siliceous stromatolites rich in kerogen or to adjacent jaspilites from a palaeogeographic viewpoint the highest concentrations of metals occur at the boundary between the oxidic facies stromatolites jaspilites and intercalations of other rocks and the reduced facies black shales where a syndiagenetic geochemical barrier developed mineralization was significantly influenced by subalkaline volcanism stromatolites of an intertidal type apparently formed where volcanoes rose to sea level stromatolitic breccias are intruded by chromium rich green quartz veins and locally covered by tuffs

the ad 365 crete earthquake and possible seismic clustering during the fourth to sixth centuries ad in the eastern mediterranean a review of historical and archaeological data abstract historical and archaeological data are used to test geological claims that in the fourth to sixth centuries ad the eastern mediterranean experienced an unusual clustering of destructive earthquakes the early byzantine tectonic paroxsym a review of historical accounts of a notable earthquake at this time that of 21 july ad 365 indicates that this event destroyed nearly all the towns in crete and was followed by a tsunami which devastated the nile delta the ad 365 event was also probably responsible for reported or observed destruction in ancient towns of west cyprus and libya this earthquake is most likely to be identified with a hellenic arc subduction zone event of great m 8 magnitude as testified by up to 9 m of uplift in western crete dated by previous geological studies to around this time historical and archaeological data also support the hypothesis that the fourth to sixth centuries ad was a period of abnormally high seismicity in the eastern mediterranean the high seismicity rates of this period may reflect a reactivation of all plate boundaries in the region dead sea transform east anatolian fault north anatolian fault hellenic arc cyprus arc fault

geological fullerenes review and analysis abstract fullerenes have been reported from numerous terrestrial and meteoritic sources but only at low concentrations the occurrences are associated with localized energetic events such as lightning impacts of extraterrestrial objects and wildfires great interest has also been generated by a series of papers that report noble gases with anomalous isotopic compositions encapsulated within fullerenes in spite of all of the published work many unresolved questions remain about the identity and formation of fullerenes in geological environments

deposition models for chronological records abstract long term sedimentary sequences provide a wealth of useful information for research into the palaeo environment especially in relation to past climate change shorter records provide similar information in many archaeological contexts however if such records are to be used to provide precise timing of events and more critically the relative timing between different records methods are needed to provide accurate and precise age depth models for these sequences given the imprecision of individual calibrated radiocarbon determinations it is necessary to use the information we have about the deposition process to refine our chronologies and also to provide interpolation between dated levels in any sequence even with layer counted chronologies the uncertainties are sometimes hard to quantify this paper outlines a range of bayesian models for deposition which have been implemented in the computer programme oxcal these models can be used to combine information from the sediments themselves with radiocarbon or other direct dating information such models have the potential to integrate information between different records and provide a coherent chronology on which to base environmental or archaeological research