evaluation of fault slip potential due to shearing of fault asperities1 mining activities in underground mines could induce fault slip that inflicts devastating damage to mine openings thus enhancing current knowledge about fault slip taking place in underground mines is of paramount importance in this study static and dynamic analyses are performed using mine wide models encompassing a fault running parallel to a steeply dipping tabular orebody in the static analysis modelled stopes within the orebody are extracted and backfilled in accordance with a sublevel stoping method dynamic analyses may be performed depending on the stress states at the end of each mining stage during the static analysis to simulate fault slip induced by a stress drop resulting from asperity shear selected seismic source parameters of the simulated fault slip are then computed for each mining stage the relation between d h where d is distance between the fault and the orebody and h is height of the mined out ore and seismic source parameters is examined it is shown that seismic moment

a meteorological analysis of the 2013 alberta flood antecedent large scale flow pattern and synoptic dynamic characteristics abstractthe 19 21 june 2013 alberta flood was the costliest cad 6 billion natural disaster in canadian history the flood was caused by a combination of above normal spring snowmelt in the canadian rockies large antecedent precipitation and an extreme rainfall event on 19 21 june that produced rainfall totals of 76 mm in calgary and 91 mm in the foothills as is typical of flash floods along the front range of the rocky mountains rapidly rising streamflow proceeded to move downhill eastward into calgary a meteorological analysis traces an antecedent rossby wave train across the north pacific ocean starting with intense baroclinic development over east asia on 11 june subsequently downstream rossby wave development occurred across the north pacific a 1032 hpa subtropical anticyclone located northeast of hawaii initiated a southerly atmospheric river into alaska which contributed to the development of a cutoff anticyclone over alaska and a rex block ridge to the north cyclone to the south in

geochemistry and mineralogical residences of trace elements in oil shales from julia creek queensland australia abstract abundances and mineralogical residences have been determined for a comprehensive range of trace elements in julia creek oil shale many trace elements are well above normal abundances in shales of these elements v and mo are potentially useful by products whereas as se mo cd tl and u are of possible environmental or occupational health concern samples from a stratigraphic reference bore core through the toolebuc formation near julia creek in queensland were chemically analysed using the multi element techniques of neutron activation analysis and spark source mass spectrometry inter element correlation techniques selective leaching procedures and electron microprobe analyses were used to establish geochemical associations and specific mineralogical residences for a full range of elements the results provide a definitive chemical and mineralogical characterization of the oil shale and identify the major mineralogical residences of the important trace elements v occurs mainly in a mixed layer mica montmorillonite clay mineral and to a lesser extent in kerogen whereas most trace elements of environmental concern are resident in the sulphide minerals pyrite and sphalerite u is concentrated in the fluorapatite of fish debris a sound basis is established for understanding the inorganic chemistry involved in oil shale processing and waste disposal

diagenesis provenance and reservoir quality of triassic tagi sandstones from ourhoud field berkine ghadames basin algeria the triassic tagi trias argilo greseux inferieur fluvial sandstones are the main oil reservoirs in the berkine basin algeria nonetheless their provenance and diagenesis and their impact on reservoir quality are virtually unknown samples from the ourhoud field representing the lower middle and upper tagi subunits were studied using a combination of petrographic mineralogical and geochemical techniques the lower tagi sandstones have an average framework composition of q98 3f0 6r1 1 and 95 of the quartz grains are monocrystalline by contrast the middle upper tagi sandstones have an average framework composition of q88 3f9 8r1 9 and 79 7 of the quartz grains are monocrystalline the lower tagi quartz arenites derived from paleozoic siliciclastic rocks whereas the middle upper tagi subarkoses originated mainly from metamorphic terrains this change in provenance is a potential criterion for correlation within the tagi also this change has contributed to the significantly different diagenetic paths followed by the lower tagi quartz arenites and the middle upper tagi subarkoses grain coating illitic clays are abundant in the lower tagi where they exert a critical control on reservoir quality these clays are interpreted as pedogenic and or infiltrated in origin and to have had in part smectitic precursors shallow burial fe dolomite cementation was favored in the downthrown block of the field bounding fault where it contributed to the poor reservoir quality magnesite siderite cements are multiphase the earliest generation is composed of fe rich magnesite that precipitated during shallow burial from hypersaline fluids with high mg ca ratios probably refluxed residual brines associated with the liassic evaporites later magnesite siderite generations precipitated during deeper burial from waters with progressively higher fe mg ratios authigenic vermicular kaolin largely consists of dickite that replaced previously formed kaolinite dickitization was followed by late stage illitization related to the dissolution of detrital and authigenic k feldspar quartz the most abundant cement was mainly sourced by the pressure or clay induced dissolution of detrital quartz and is a critical factor controlling the reservoir quality overall quartz cement is more abundant in the lower tagi than in the middle upper tagi and this increase correlates with a decrease in average porosity within the lower tagi quartz cement abundance is stratigraphically very variable which is in part related to facies controlled variations in grain coating clay resulting in major vertical variations in reservoir quality anhydrite and barite cements postdate quartz overgrowth the sulfate necessary for their formation was likely sourced by deep subsurface dissolution of late triassic liassic evaporites

opaque minerals as keys for distinguishing oxidising and reducing diagenetic conditions in the lower triassic bunter sandstone north german basin abstract the diagenetic evolution in red and white drab parts of the bunter sandstone from outcrops and wells in the north german basin was unraveled by a detailed petrographical mineralogical and chemical study the diagenetic sequences for the red and white drab parts differ in the degree of alteration of iron bearing detrital minerals and in the authigenic opaque minerals in the white drab parts one typically sees reduction of red mica dissolution of hematite and magnetite and alteration of ilmenite and titanomagnetite to leucoxene in contrast the red parts commonly display oxidation of glauconite red zonation in ooids hematisation of magnetite biotite and magnetite host in titanomagnetite and leucoxene replacement of the ilmenite lamellae in titanomagnetite the red colour of the red bed host is due to red coatings of goethite needles and or hematite needles goethite needles precipitated in the prevailing oxidising conditions present shortly after deposition whereas pseudomorphous replacement by hematite occurred during the burial process the white drab colour of the reduced areas is the original colour of the sediment the black core in reduction spots is due to mineralization uranium and vanadium minerals coffinite montroseite and v illite in reduction spots are located close to carbonate fragments which probably contained organic matter isolated reduction spots may have formed immediately after deposition inside these were clasts eroded from algal mats formed in the sabkha environment the copper minerals typically occur in areas with high porosity reflecting the importance of access to chloride rich brines which transported dissolved copper when these brines reached reducing environments chalcocite and chalcopyrite were precipitated possibly by replacement of pyrite in the red areas these saline brines may also have promoted the second stage alteration of ilmenite in which leucoxene the first stage alteration product was impregnated with iron oxide hydroxide needles this study emphasises the importance of opaque minerals especially fe ti oxides and authigenic opaques as diagnostic for the diagenetic environment of the bunter sandstone which can thus be divided into primary reduced primary oxidised secondary reduced and secondary oxidised diagenetic environments furthermore the influence of saline brines can be detected using the opaque mineral assemblage

the continuous alteration of ilmenite through pseudorutile to leucoxene ore microscopic examinations and microprobe analyses show the alteration of ilmenite by leaching to be a continuous process proceeding from leached ilmenite through pseudorutile to leucoxene in this process which takes place near the surface and requires the presence of water a temperature of 50 c is not exceeded therefore diffusion processes are of no importance there are continuous phase transitions between ilmenite and its successive products pseudorutile with its iron poor members leached pseudorutile in particular is unstable and decomposes into leucoxene as a result of this and also of leucoxenic changes brought about by recrystallization there are sharp grain boundaries towards other alteration products simulating discontinuous leaching processes ilmenite leucoxene and their intermediate products are well distinguishable from each other by ore microscopic and subordinate also by x ray methods with ore microscopic studies enabling this distinction to be made faster and more easily water is the main agent in the leaching process which keeps going on as long as there is iron present that is able to migrate the continuous alteration of ilmenite can be expressed in terms of two reactions a 3fe2 tio3 fe3 x2 fe 23 x3 13 x ti3o9 in this equation x 0 3 x 0 corresponds to ilmenite x 3 to pseudorutile in the range of x 0 2 1 leached ilmenite occurs reaction a is established by oxidation and leaching of iron b fe23 ti3o9 fe2 y3 ti3o9 3y oh 3y in this equation y 0 2 y 0 corresponds to pseudorutile y 2 to leucoxene the range of y from 0 8 1 4 is identical with leached pseudorutile reaction b can be explained by hydrolization and leaching of iron whereas reaction a includes all phases representing oxides with different fe2 fe3 ratios reaction b comprises all phases with iron occurring in its trivalent state and the o oh ratio increasing as the fe3 content is decreasing

processes controlling the structure and longevity of two quasi linear convective systems crossing the southern new england coast abstractthis paper explores the structural evolution and physical processes that explain the modification of two quasi linear convective systems qlcss that encountered the densely populated new york city atlantic coastal region one qlcs on 31 may 2002 traversed the atlantic coastal boundary with little change in its intensity producing widespread severe wind damage across new york city and long island during this event warm air advection at 925 hpa helped destabilize the layer above this level over the coastal zone while the marine boundary layer deepened below this level the 0 3 km line perpendicular vertical wind shear was relatively strong which supported ascent along the leading edge of the diabatically generated cold pool the surface based convective system became slightly elevated as it moved over the marine waters in contrast the 23 july 2002 qlcs decayed upon encountering the atlantic coastline despite its coincidence with a surface cold front the most unstable cape values during thi

deducing source rock lithology from detrital rutile geochemistry an example from the erzgebirge germany abstract this study evaluates the applicability of rutile trace element geochemistry to provenance studies the study area is the erzgebirge in eastern germany where metamorphic rocks ranging from lower greenschist facies conditions up to granulite facies conditions are exposed we collected sand and rock samples from small catchment areas for a comparative analysis of rutile geochemistry using wavelength dispersive electron microprobe our results show that rutile geochemistry is a powerful tool in provenance studies allowing for the identification of source lithologies and an evaluation of the host orogen s metamorphic history the log cr nb ratio has proven to be decisive in discriminating between mafic and metapelitic lithologies it is also useful for identifying different source rocks when plotted versus a third element or proxy furthermore our results suggest that rutile thermometry can be applied to a much wider range of lithologies than previously assumed a quantification of temperature populations within single sand samples shows that at high grade metamorphic conditions such as those found in the erzgebirge more than 65 of rutiles do not re equilibrate during retrograde metamorphism and thus retain their peak temperature chemistry such samples which have equilibrated at recent metamorphic conditions can be identified by their 2 standard deviations of less than 120 c below 550 600 c no complete equilibration is reached rutiles from greenschist facies and lower metamorphic conditions in the erzgebirge still inherit relict temperatures from a former metamorphic cycle they partly record very high temperatures 950 c and supposedly derive from erosion of the west african craton in ordovician time

organization and environmental properties of extreme rain producing mesoscale convective systems this study examines the radar indicated structures and other features of extreme rain events in the united states over a 3 yr period a rainfall event is defined as extreme when the 24 h precipitation total at one or more stations surpasses the 50 yr recurrence interval amount for that location this definition yields 116 such cases from 1999 to 2001 in the area east of the rocky mountains excluding florida two kilometer national composite radar reflectivity data are then used to examine the structure and evolution of each extreme rain event sixty five percent of the total number of events are associated with mesoscale convective systems mcss while a wide variety of organizational structures as indicated by radar reflectivity data are seen among the mcs cases two patterns of organization are observed most frequently the first type has a line often oriented east west with training convective elements it also has a region of adjoining stratiform rain that is displaced to the north of the line the second type has a back building or quasi stationary area of convection that produces a region of stratiform rain downstream surface observations and composite analysis of rapid update cycle version 2 ruc 2 model data reveal that training line adjoining stratiform tl as systems typically form in a very moist unstable environment on the cool side of a preexisting slow moving surface boundary on the other hand back building quasistationary bb mcss are more dependent on mesoscale and storm scale processes particularly lifting provided by storm generated cold pools than on preexisting synoptic boundaries

facies and provenance analysis of upper carboniferous to lower permian fan sequences at a convergent plate margin using phyllosilicates heavy minerals and rock fragments erbendorf trough f r g the erbendorf trough is a narrow permo carboniferous graben in the northeast bavarian crystalline basement at the saxothuringian moldanubian plate edge its elastic and volcanic rocks reflect a complex story of alluvial fan progradation and retreat unit i precambrian gneissic bedrock is followed by units ii to v a wet mixed fan debris stream flows braided streams peat swamps organic lake units vi to x reflect a retrogradational dry fan braided streams calcretes flood plain deposition with tuffaceous interbeds units xi to xii are acid extrusive rocks the uppermost part hydrothermally altered and units xiii to xiv denote a progradational dry fan the wet fan at the base is characterized by a predominance of illite stable to intermediate heavy mineral associations zircon and garnet and a clast community pointing to medium pressure metamorphic rocks in the variscan nappe the following dry fan contains various 14 a phyllosilicates besides white mica its heavy mineral suite contains more labile constituents apatite and amphibole gneissic pebbles accompany those from acid volcanic and plutonic rocks the volcanogenic rocks contain expandable 14 a phyllosilicates formed by devitrification anatase and brookite dominate the heavy minerals tio2 associated with phosphate indicates hydrothermal alteration of host rock whereas detrital tio2 and a high ztr zircon tourmaline rutile index reflect paleosol formation as shown at the wet dry fan boundary fan progradation occurred under semi arid conditions with kaolinization and formation of illite partly detrital and a moderately stable heavy mineral association apatite dominated owing to the kaolinization only quartz bearing gneisses were preserved the facies succession reflect the evolution from a fault bordered basin with various fan sections proximal vs distal preserved into a caldera like volcanotectonic depression regionally the grain size intervals reflect a passage from recycled orogen into a transitional arc which accords with the late variscan horizontal gliding of the moldanubian plate over the saxothuringian plate and basement uplift proximal to this suture

rock mechanical investigations of seismic events in a deep longwall coal mine seismic events i e fractures in rock that radiate detectable seismic waves are a worldwide phenomena associated with mining and reservoir exploitation longwall mining in german coal mines often causes seismic events which can be felt at surface where they can lead to a considerable annoyance of residents and sometimes even lead to minor damages of buildings and infrastructure strong seismic events are in a large part responsible for a more and more decreasing community acceptance of mining the mines therefore have to investigate the local conditions which cause the generation of seismic events to find ways of avoiding strong mining induced seismic events this paper describes the research on mining induced seismicity around a specific active longwall at 1100 m depth under several previously mined longwall panels seismic events are recorded by a local network featuring 15 surface and six subsurface stations location and fault plane solutions show the occurrence of at least three different event types which are characterized by distinct modes of failure underground core drilling and an extensive rock testing program are used to build up a rock mechanical model featuring a multi layer strata for use with numerical analyses the numerical model is able to explain the different failure mechanisms as fault activation remnant pillar punching and beam failure the use of rock mass classification rock mass strength criteria and in situ stresses together with 2d and 3d numerical analyses facilitates the evaluation of the results from seismology approaches and makes future analysis of longwall related seismic events possible

moist dynamics and orographic precipitation in northern and central california during the new year s flood of 1997 abstract the dynamics of moist orographic flows during the january 1997 floods in northern and central california are investigated using numerical simulations computed with the fifth generation pennsylvania state university national center for atmospheric research psu ncar mesoscale model mm5 early in the event 31 december 1996 1 january 1997 the low level winds offshore of california s central coast were blocked by the topography of the santa lucia range and the low level winds in the central valley were blocked by the topography of the central sierra nevada range in contrast moisture laden winds along the northern coast ranges and the northern sierra nevada flowed over topographic barriers as the core of humid air migrated to the south over 24 h the low level barrier jets weakened as the atmospheric stability decreased bringing heavy rainfall to the central and southern sierra nevada at the end of the event the heavy precipitation during this event was largely controlled by the interactio

numerical simulations of the 2013 alberta flood dynamics thermodynamics and the role of orography abstractthe 19 21 june 2013 alberta flood was the second costliest 6 billion cad natural disaster in canadian history trailing only the 2016 fort mcmurray alberta canada wildfires one of the primary drivers was an extreme rainfall event that resulted in 75 150 mm of precipitation in the foothills west of calgary canada here the mesoscale dynamics and thermodynamics that contributed to the extreme rainfall event are elucidated through high resolution numerical model simulations in addition terrain reduction model sensitivity experiments using gaussian smoothing techniques quantify the importance of orography in producing the extreme rainfall event it is suggested that the extreme rainfall event was initially characterized by the formation of a surface cyclone on the eastern side of the canadian rockies due to quasigeostrophic qg mechanisms orographic processes and diabatic heating feedbacks maintained the surface cyclone throughout the event extending the duration of both easterly upslope

using tropopause maps to diagnose midlatitude weather systems the use of potential vorticity pv allows the efficient description of the dynamics of nearly balanced atmospheric flow phenomena but the distribution of pv must be simply represented for ease in interpretation representations of pv on isentropic or isobaric surfaces can be cumbersome as analyses of several surfaces spanning the troposphere must be constructed to fully apprehend the complete pv distribution following a brief review of the relationship between pv and nearly balanced flows it is demonstrated that the tropospheric pv has a simple distribution and as a consequence an analysis of potential temperature along the dynamic tropopause here defined as a surface of constant pv allows for a simple representation of the upper tropospheric and lower stratospheric pv the construction and interpretation of these tropopause maps which may be termed isertelic analyses of potential temperature are described in addition techniques to construct dynamical representations of the lower tropospheric pv and near surface potential temperature which complement these isertelic analyses are also suggested case studies are presented to illustrate the utility of these techniques in diagnosing phenomena such as cyclogenesis tropopause folds the formation of an upper trough and the effects of latent heat release on the upper and lower troposphere

provenance of the carboniferous hochwipfel formation karawanken mountains austria slovenia geochemistry versus petrography this study focuses on the carboniferous sediments of the karawanken mountains austria slovenia to identify possible source areas and their geotectonic setting provenance analyses have been applied using petrographical and geochemical approaches what also lead to an evaluation of the used methods within the hochwipfel formation five stratigraphic related petrofacies groups can be defined using the sandstone component inventory homogenous provenance results based on major element and trace element data suggest an active continental margin continental island arc with probably an intraplate signature provenance analyses of light minerals point to source areas with basement rocks mainly metamorphic arc material and sedimentary rocks in combination the rapid and highly variable change of provenance signatures within the stratigraphic succession of the petrofacies types excludes a single provenance in the western part of the karawanken mountains additionally changes in composition of the individual petrofacies groups correlate with the stratigraphy in the eastern part varying contents of garnet chromite hornblende and epidote within the sedimentary succession of the hochwipfel sandstones can partly be attributed to geodynamical changes in the hinterland the chemical compositions of garnets tourmalines and chromites confirm the results of both geochemistry and sediment petrography in a quantitative approach based on petrography we can see an equal mixture of all source areas whereas quantification with a geochemical approach results in c 11 of material that can be attributed to a passive continental margin source 28 to 37 to an active continental margin c 44 to a magmatic arc setting and 16 to 19 to an oceanic within plate source area the resulting model for the geodynamical setting of the hochwipfel basin during the late palaeozoic can be best explained by a forearc basin in the eastern part and various pull apart basins in the western part connected through bypasses at the continental margin of gondwana and the palaeotethys as an additional outcome this study clarifies that geochemically derived provenance results based on bulk rock and mineral composition recognize best complex geodynamical settings and a mixture of sources since they incorporate best the provenance significant lithic components on the other hand it points out that an application of additional petrological approaches does not necessarily lead to further information and an elimination of errors but could be essential to define general information of the investigated stratigraphy like the correlation of deposits with stratigraphy petrofacies groups

appalachian cold air damming abstract appalachian cold air damming is investigated by means of 1 a 50 yr monthly climatology 2 a synoptic case study of the event of 21 23 march 1985 and 3 an investigation of the flow structure and force balance within the cold dome the climatology reveals cold air damming is a year round phenomenon in the southern appalachians with the most frequent prolonged and intense events occurring in winter particularly december and march when three five events per month can be expected cold air damming is least frequent and intense in july the synoptic case study reveals that cold air damming is critically dependent upon the configuration of the synoptic scale flow the cold dome can be identified by a u shaped ridge trough in the sea level isobar thermal patterns and the 930 mb height temperature fields representative of conditions at the base of the inversion overlying the cold dome differential horizontal and vertical thermal advection as well as adiabatic and evaporative cooling are r

the permian triassic boundary in the central european basin magnetostratigraphic constraints some stratigraphic interpretations concerning correlation of the permian triasssic transition beds from the central european boreal and tethyan basins are inconsistent with the existing magnetostratigraphic data in addition the suggestion that the permian triassic boundary is located in the lower part of the calvorde formation of the central european basin cannot be supported by magnetostratigraphic data results of magnetostratigraphic correlation show that in the polish part of the central european basin the permian triassic boundary is close to the boundary between the uppermost zechstein and the lower buntsandstein it is located within the reversed magnetozone pzr1 identified in the upper part of the rewal formation in the german part of the central european basin the permian triassic boundary can be located within the reversed magnetozone zrz that covers most of the brockelschiefer a higher stratigraphic location of this boundatry i e inside the lowermost buntsandstein requires a reversed polarity record to be found within the basal triassic normal polarity zone

formation and composition of rhabdophane bastnasite and hydrated thorium minerals during alteration implications for geochronology and low temperature processes abstract an investigation of accessory minerals in plutonic rocks from central madagascar reveals local very low grade alteration of the primary ree and th bearing phases monazite lree th po4 allanite careefe2 al2 sio7 sio4 o oh and thorite thsio4 all examples are found in relatively fresh looking samples in which alteration occurs on the micron to submicron scale the alteration occurs associated with micro fissures and predominantly affects the accessory minerals one type of alteration is replacement of thorite and monazite by thorogummite th u sio4 oh 4 and rhabdophane reepo4 h2o some of these secondary phases grow topotactically on the original magmatic crystals during development of rhabdophane pb and th can be transferred from the monazite precursor to rhabdophane resulting in similar apparent ages for both phases a second type of alteration has been investigated in two granites where bastnasite reeco3f forms at the expense of allanite which requires a fluid containing h2o co2 and f in either type of alteration mass transport of pb is deduced from galena development in the vicinity of the altered mineral in other examples mass transport of ree is assumed based on ree fractionation in secondary phases th rich minerals th rich monazite thorite are more affected by alteration than th poor phases this may be due to chemical disequilibrium at low temperatures or partial metamictization before alteration overlooking such alterations can lead to pitfalls during dating

dynamic model validation using blast vibration monitoring in mine backfill abstract sublevel stoping mining methods with delayed backfill are employed for mining steeply dipping ore deposits at deeper horizons cemented rockfill crf is used as a backfilling material for open stopes formed during mining in primary secondary mining sequence blast vibrations are induced in crf during the extraction of adjacent stopes higher magnitude of blast vibrations may destabilize crf causing failure and dilution of precious ore this paper presents a methodology for calibrating a flac3d numerical model encompassing mine backfill with blast induced vibration data recorded from field instrumentation two flac3d models are prepared one for simulating the blasting process and the other is prepared for backfill stability analysis the first model resulted in load vectors to be applied to backfill and rock interface the second model showed that the backfill fails under the blast vibrations induced by the adjacent production stope the results of the back analysis of fill failure are presented and discussed the methodology may serve as numerical model calibration procedure for mine backfill

authigenic heavy minerals a clue to unravel supergene and hypogene alteration of marine and continental sediments of triassic to cretaceous age se germany abstract siliciclastic continental marine sediments of triassic through jurassic age resting unconformably on the crystalline rocks of the central european variscides and marine deltaic sediments of cretaceous age deposited in a narrow embankment are well exposed in the wackersdorf area se germany these sediments were investigated for their variegated spectrum of authigenic heavy minerals hm and heavy mineral hm aggregates the majority of which belongs to the semi opaque group of minerals using petrographic and ore microscopy supplemented by sem edx and by empa these hms originated from supergene weathering diagenesis and hypogene alteration hydrothermal processes related to faults and unconformities the physical and chemical conditions during which these authigenic minerals developed are discussed by means of eh ph diagrams under different temperature conditions ilmenite pseudorutile anatase series may be used as a measure for the intensity of supergene alteration under rising oxygen fugacity pseudorutile and anatase also formed during hypogene alteration and developed different crystal morphologies compared with their supergene counterparts found in the above series the authigenic hm fluorite barite niccolite acanthite silver bravoite ni marcasite pyrite sphalerite galena chalcopyrite chalcocite and rhabdophane ce were produced by hypogene hydrothermal processes the hypogene mineralization in the mesozoic foreland sediments belongs to two types 1 epi mesothermal ree f mineralization controlled by the structural reactivation along a deep seated lineamentary fault zone and 2 epithermal ni cu zn as s mineralization related to the geohydraulic plane of the late variscan unconformity permo triassic peneplain

influence of terrain resolution on banded convection in the lee of the rocky mountains abstracton 16 17 february 2007 snowbands formed in the lee of the rocky mountains in wyoming colorado and nebraska on the anticyclonic shear side of a midlevel jet streak two types of bands were prevalent a longer wider band associated with frontogenesis along an equatorward moving cold front major band and multiple shorter narrower bands farther poleward minor bands to understand how the upstream terrain affected the occurrence and intensity of the bands multiple mesoscale model simulations were performed in which the terrain was incrementally smoothed the evolutions of the synoptic patterns were similar in all simulations that included topography but the synoptic pattern differed and no bands developed in a simulation with a flat land surface these results allowed a focus on the changes to the banded precipitation due to the terrain resolution remarkably although the exact location of the bands differed from run to run the bands in all simulations with topography were in roughly the s

sequence stratigraphic framework of the german triassic abstract the sequence stratigraphic methodology can be readily applied to the cratonic basin fill of the classic german triassic consisting of shallow marine to terrestrial mixed carbonate siliclastic rocks the whole triassic succession represents a second order transgression regression cycle built by third order depositional sequences systems tracts and parasequences many bounding surfaces represent widely used marker beds long used in classical lithostratigraphy using a synthesis of outcrop well log and literature data on stratal geometry facies cycle stacking patterns and paleogeography a regional chart of coastal onlap was constructed within the limitations of the presently available biostratigraphic data the observed cycles appear to correlate fairly well with those in other areas but include a number of additional sequences not included in the haq et al 1988 chart comparative analysis of regional onlap curves from different globally spread triassic basins together with an improved biostratigraphy will be necessary to relate the accommodation changes to eustatic versus tectonic and climatic controls and to produce a refined eustatic chart the german basin could provide a favourable reference point for such an analysis

quantifying sand provenance and erosion marsyandi river nepal himalaya we use petrographic and mineralogical data on modern sediments to investigate erosion patterns in the marsyandi basin of the central himalaya a privileged natural laboratory in which a series of multidisciplinary geomorphological sedimentological geochemical and geochronological studies have been recently carried out to unravel the interrelationships between tectonic climatic and sedimentary processes in high relief orogenic belts although relative erosion patterns are effectively constrained by analyses of replicate samples along six successive tracts of the marsyandi river uncertainties are caused by potential compositional variation between the monsoon and post monsoon season estimates of erosion rates are significantly affected by poor knowledge of total sediment flux through the basin ourresults support focusederosion of the southern tectonically lower part of the greater himalayain the hangingwall of the mct zone where thesummer monsoon reachesitspeak intensity up to 5 m a andsediment yieldsanderosion ratesreach14 100 3400t km 2 and 5 1 1 2 mm a erosion rates sharply decrease southward in low relief lesser himalayan units 1 6 0 6 mm a and also progressivelydecreasenorthwardsinthehigh altitude tectonically upperpartofthegreaterhimalaya whererainfalldecreasesrapidly to b2 m a even areas of extreme topography such as the manaslu granite are characterized by relatively low erosion rates 2 4 0 9 mm a because precipitations become too scarce to feed significant ice flux and glacial activity monsoonal rainfall decreases further tob0 5 m a in the tethys himalayan zone farther north where erosion rates are 1 mm a coupling between erosion and peak monsoonal rainfall along the southern front of the greater himalaya is consistent with both channel flow models of tectonic extrusion

numerical simulation of rock mass vibrations induced by nearby production blast it is of importance to understand the effect of production blasts on the surrounding rock formations in underground mines this study presents a numerical procedure to simulate stress waves resulting from nearby production blasts first the damping coefficient and peak borehole pressure are calibrated using a dynamic numerical model of a single blast hole the resulting time varying particle velocities in the surrounding rock mass at the specified points are calculated these are then used as input parameters in a three dimensional mine wide model considering a positional relationship between the blast hole and the specified points on the wall rock the mine wide model encompasses a fault running parallel to a steeply dipping tabular ore deposit dynamic analysis simulating the effect of production blasts is conducted after the extraction of mining blocks with static analysis in this study variations of stresses along the fault due to blast induced stress waves are examined results demonstrate that