petrographic constraints on the diversity of chondrule reservoirs in the protoplanetary disk abstract chondrules from different chondrite groups show characteristic properties including abundances of different chondrule textural types chondrule sizes oxygen isotope compositions chondrule bulk compositions and petrographic properties of type i and type ii chondrules including abundances of relict grains overall it can be argued that each chondrite group sampled a unique chondrule reservoir and that chondrite groups may represent fractions of larger reservoirs that are represented by chondrite classes these observations provide constraints for models of the early solar system in which it is necessary to establish multiple separate chondrule reservoirs and maintain them over extended time periods models for accretion of chondrite parent bodies must be able to account for localized accretion of chondrules that were formed in spatially or temporally separated reservoirs

application of two dimensional gravity models as input parameters to balanced cross sections across the margin of the east european craton in se poland abstract our paper demonstrates how two dimensional density models can deliver critical constraints that permit construction and validation of geological models in an underconstrained subcropped fold and thrust belt as a case study we use a newly discovered thrust and fold belt developed above the margin of the east european craton eec in se poland a geological model constructed using gravity data resolved the basement cover interface and a top cambrian horizon this model was used as a framework for cross section construction employing at this step also borehole and seismic evidence two cross sections were created to address a source of uncertainty related to non uniqueness of gravity modelling with different emphasis on gravimetric vs geological evidence model 1 strictly obeys the top cambrian derived from gravity modelling that was treated as an envelope of deeper structures model 2 allowed for local departures from the gravity model especially in the case of conflicts with formation thicknesses the comparison between the present structure and restorations allowed for separating effects of caledonian and variscan shortening although the fit of both models to the gravity data is satisfactory model 2 better complies to geological constraints resolving the long discussed problem concerning the distribution and intensity of caledonian tectonics across the sw periphery of the eec

abundances of presolar silicon carbide grains in primitive meteorites determined by nanosims abstract it has been suggested that the matrices of all chondrites are dominated by a common material with ivuna like ci abundances of volatiles presolar grains and insoluble organic matter iom e g alexander 2005 however matrix normalized abundances of presolar silicon carbide sic grains estimated from their noble gas components show significant variations in even the most primitive chondrites huss and lewis 1995 huss et al 2003 in contradiction to there being a common chondrite matrix material here we report presolar sic abundances determined by nanosims raster ion imaging of iom extracted from primitive members of different meteorite groups we show that presolar sic abundance determinations are comparable between nanosims instruments located at three different institutes between residues prepared by different demineralization techniques and between microtomed and non microtomed samples our derived sic abundances in cr chondrites are comparable to those found in the ci chondrites 30 ppm and are much higher than previously determined by noble gas analyses the revised higher cr sic abundances are consistent with the crs being amongst the most primitive chondrites in terms of the isotopic compositions and disordered nature of their organic matter similar abundances between cr1 cr2 and cr3 chondrites indicate aqueous alteration on the cr chondrite parent body has not progressively destroyed sic grains in them a low sic abundance for the reduced cv3 rbt 04133 can be explained by parent body thermal metamorphism at an estimated temperature of 440 c minor differences between primitive members of other meteorite classes which did not experience such high temperatures may be explained by prolonged oxidation at lower temperatures under which sic grains formed outer layers of sio2 that were not thermodynamically stable leading to progressive degassing destruction of sic

variscan to alpine heterogeneous palaeo stress field above a major palaeozoic suture in the carpathian foreland southeastern poland abstract the tectonic evolution of the region adjacent to the sw border of the east european craton is crucial for understanding the palaeozoic amalgamation of europe and its later evolution we present a structural analysis of the brittle deformation fault slip data inversion and folding carried out in the cambrian to cenozoic rocks of the european platform in se poland to characterize the late palaeozoic maastrichtian palaeocene and miocene tectonics of this region the variscan late carboniferous palaeo stress pattern was characterized by n s to nne ssw oriented compression as inferred from the folding of the palaeozoic mainly devonian rocks the compression was associated with the northwesterly present day coordinates motion of gondwana towards the northerly situated laurussia subsequently the mid polish trough mpt developed in an extensional regime the stress regime changed to compressional at the maastrichtian palaeocene transition in response to the africa europe plate kinematics the compressional regime induced the tectonic inversion of the mid polish trough the stress pattern was characterized by ne sw oriented compression in the holy cross mts hcm area and in the radomsko high folds and faults in the mesozoic cover revealed a sinistral reactivation of the holy cross fault hcf and of nw se trending faults the alpine stress patterns were related to the subduction of the european platform beneath the carpathian orogen the flexural bending of the subducted lithosphere induced a homogeneous middle miocene n s extension in the carpathian foreland subsequently the northward propagation of the carpathian front resulted in late middle miocene n s compression restricted to the proximal area of the frontal thrusts implied by a strain partitioning at a low friction contact between the carpathian nappes and the european platform since the palaeozoic the teisseyre tornquist zone ttz behaved as lithospheric weak zone which has been reactivated during the maastrichtian palaeocene change in stress regime it resulted in the tectonic inversion of the polish trough inherited faults conditioned superficial stress perturbations and focused the deformation

geophysical constraints on the crustal structure of the east european platform margin and its foreland based on the polcrust 01 deep reflection seismic profile abstract a new 240 km long deep seismic reflection profile polcrust 01 was recently acquired in se poland crossing the east european platform eep margin south east of the north german polish caledonides ngpc here we document geophysical field work and subsequent data processing and modeling results obtained from reflection seismic data are augmented by results of the first arrival tomography applied to co located extended offset refraction data as well as potential field modeling and comparison with the available wide angle reflection refraction data our preferred model of the crustal structure derived by integrating seismic potential field and geological data is composed of crustal blocks terranes separated by nearly vertical faults these are i intact part of the eep ii ysogory terrane iii malopolska terrane and iv carpathian mts with their basement reflective lower crust of the eep can be an inherited feature of crustal extension rifting or compressional tectonics acting at the cratonic margin the teisseyre tornquist zone ttz is depicted as a caledonian transcurrent accretion zone corresponding with the near vertical tomaszow fault bounding the ysogory terrane to the east the crust of the ysogory terrane suggests eep affinity although its middle lower crust thickness is highly reduced the malopolska terrane seems to be internally subdivided into blocks of different magnetic properties of the lower crust the carpathian frontal thrust is associated with a change in the rock properties in the deep basement an unknown crustal block which is not visible in seismic data alone the interpreted structure of the caledonian terranes and their tectonic boundaries favors a transcurrent style of a crustal accretion along the central and se polish segments of the ttz implying a very complex nature of the caledonian accretionary belt of central europe from an array of terranes displaced along the ttz to an accretionary wedge of the collisional ngpc orogen between nw poland and southern north sea area

physical properties of chondrules in different chondrite groups implications for multiple melting events in dusty environments chondrite groups cv ck cr with large average chondrule sizes have low proportions of rp plus c chondrules high proportions of enveloping compound chondrules high proportions of chondrules with thick igneous rims and relatively low proportions of type i chondrules containing sulfide in contrast chondrite groups cm co oc r eh el with smaller average chondrule sizes have the opposite properties equilibrated ck chondrites have plagioclase with relatively low na equilibrated oc r eh and el chondrites have more sodic plagioclase enveloping compound chondrules and chondrules with igneous rims formed during a remelting event after the primary chondrule was incorporated into a dustball repeated episodes of remelting after chondrules were surrounded by dust would tend to produce large chondrules rp and c chondrules formed by complete melting of their precursor assemblages remelting of rp and c chondrules surrounded by dust would tend to produce porphyritic chondrules as small dust particles mixed with the melt providing nuclei for crystallizing phenocrysts this process would tend to diminish the numbers of rp and c chondrules correlations among these chondrule physical properties suggest that chondrite groups with large chondrules were typically surrounded by thick dust rich mantles that formed in locally dusty nebular environments chondrules that were surrounded by thick dust mantles tended to cool more slowly because heat could not quickly radiate away slow cooling led to enhanced migration of sulfide to chondrule surfaces and more extensive sulfide evaporation these chondrules also lost na the plagioclase that formed from equilibrated ck chondrites was thus depleted in na

different modes of the late cretaceous early tertiary inversion in the north german and polish basins several selected seismic lines are used to show and compare the modes of late cretaceous early tertiary inversion within the north german and polish basins these seismic data illustrate an important difference in the allocation of major zones of basement thick skinned deformation and maximum uplift within both basins the most important inversion related uplift of the polish basin was localised in its axial part the mid polish trough whereas the basement in the axial part of the north german basin remained virtually flat the latter was uplifted along the sw and to a smaller degree the ne margins of the north german basin presently defined by the elbe fault system and the grimmen high respectively the different location of the basement inversion and uplift within the north german and polish basins is interpreted to reflect the position of major zones of crustal weakness represented by the wnw ese trending elbe fault system and by the nw se striking teisseyre tornquist zone the latter underlying the mid polish trough therefore the inversion of the polish and north german basins demonstrates the significance of an inherited basement structure regardless of its relationship to the position of the basin axis the inversion of the mid polish trough was connected with the reactivation of normal basement fault zones responsible for its permo mesozoic subsidence these faults zones inverted as reverse faults facilitated the uplift of the mid polish trough in the order of 1 3 km in contrast inversion of the north german basin rarely re used structures active during its subsidence basement inversion and uplift in the range of 3 4 km was focused at the elbe fault system which has remained quiescent in the triassic and jurassic but reproduced the direction of an earlier variscan structural grain in contrast n s oriented mesozoic grabens and troughs in the central part of the north german basin avoided significant inversion as they were oriented parallel to the direction of the inferred late cretaceous early tertiary compression the comparison of the north german and polish basins shows that inversion structures can follow an earlier subsidence pattern only under a favourable orientation of the stress field a thick zechstein salt layer in the central parts of the north german basin and the mid polish trough caused mechanical decoupling between the sub salt basement and the supra salt sedimentary cover resultant thin skinned inversion was manifested by the formation of various structures developed entirely in the supra salt mesozoic cenozoic succession the zechstein salt provided a mechanical buffer accommodating compressional stress and responding to the inversion through salt mobilisation and redistribution only in parts of the ngb and mpt characterised by either thin or missing zechstein evaporites thick skinned inversion directly controlled inversion related deformations of the sedimentary cover inversion of the permo mesozoic fill within the mid polish trough was achieved by a regional elevation above uplifted basement blocks conversely in the north german basin horizontal stress must have been transferred into the salt cover across the basin from its sw margin towards the basins centre this must be the case since compressional deformations are concentrated mostly above the salt and no significant inversion related basement faults are seismically detected apart from the basin margins this strain decoupling in the interior of the north german basin was enhanced by the presence of the elbe fault system which allowed strain localization in the basin floor due to its orientation perpendicular to the inferred late cretaceous early tertiary far field compression

tracing tectonic deformation using the sedimentary record an overview tectonic activity on a range of scales is a fundamental control on sedimentary activity the range of structural deformation within a region extends from the plate tectonic scale governing for example rift initiation to the basin scale with the formation of basin bounding faults internal basin configuration is also strongly influenced by tectonic activity however the relationship between tectonic activity and sedimentation is a complex one given the many additional factors which can also influence sedimentary activity including erosion sediment transport source area lithology groundwater chemistry range of depositional environments climate eustasy and the relative location of an area and its distality to marine influences in this paper we provide a selective overview of the issues associated with the interlinked themes of tectonics and sedimentation examining the main basin types forming in both extensional and compressional plate settings we then review the various models of sedimentation in the selected basins both on a local and a basinal scale finally we look to the future providing a series of possible research areas almost exclusively multidisciplinary which would help to improve existing models of interlinked sediment tectonics systems

spatiotemporal relationship between temperature and precipitation in inland china from meteorological data and paleoclimatic implications for lacustrine oxygen records abstract the factors controlling climate in china s western interior are numerous and quite complex these vary on seasonal to multi millennial time scales as a result of changing dominance of influence from the westerlies and the asian and indian monsoon systems these in turn respond to additional factors such as the dynamics of the walker and hadley circulation in the pacific and indian ocean basins the strength of the siberian and northwest pacific highs and on long timescales to changes in the distribution of solar insolation resulting from orbital forcing here we use the empirical orthogonal function eof analysis to investigate the spatiotemporal patterns of climate in china s western interior during the last 15 ka as revealed from a suite of 17 lacustrine carbonate 18o records based on similarities to the eof analysis of the modern data we interpret the first two leading eigenmodes of the paleodata sets as p and t respectively other climatic proxy data from this region appear to agree well with this interpretation our analysis reveals a discrete change in the spatial eof patterns occurring at circa 7 5 6 ka bp with respect to the patterns observed prior to this these patterns suggest that the arid nw region of the study area became significantly wetter following this juncture but that the asian monsoon influenced se region of the study area along the eastern flank of the tibetan plateau became drier a more complex pattern of change is revealed by the second rank eof interpreted as temperature this shows a discrete change at 7 5 6 ka bp from cooler to hotter temperatures on the central tibetan plateau but slightly cooler temperatures in the lowland monsoon affected area se after 6 ka bp we interpret both these sets of changes to result from more persistent high pressure over the tibetan plateau during boreal summer with a resultant enhancement of moisture transport by the westerlies and diminished monsoonal flow following 6 ka bp

introduction geological and geophysical studies in the trans european suture zone the trans european suture zone tesz is the boundary between ancient precambrian lithosphere of the east european craton eec and the younger lithosphere beneath the latest neoproterozoic palaeozoic mobile belts of western europe the former is characterized by a thick crust c 45 km low heat flow and a tectono thermal age of about 3000 to 800 ma the latter by a thinner crust c 30 km higher heat flow and a tectonothermal age of 560 to 290 ma these contrasting types of crust were juxtaposed during the caledonian and variscan orogenic episodes the crystalline basement of the tesz is largely concealed by sedimentary basins controlled by the reactivation of structures within the suture zone during permian mesozoic extension and cenozoic inversion the pre permian evolution of the craton and the mobile belts and the location of the sutures is inferred from isolated outcrops hundreds of boreholes and geophysical evidence existing seismic data demonstrates that the tesz is rather narrow and has an expression at all levels of the lithosphere and deep into the asthenosphere teleseismic studies have demonstrated that the differences in the velocity structure of the asthenospheric and lithospheric mantle across the tesz persist to depths of c 400 km zielhus nolet 1994

the drowning of a carbonate platform an example from the devonian carboniferous of the southwestern holy cross mountains poland the broad middle devonian carbonate platform of the holy cross mountains was fragmented during the frasnian and afterwards submerged as isolated blocks and transformed into a topographic depression the section exposed in the ostrowka quarry illustrates a well documented drowning of the last small fragment seamount of this carbonate platform which submerged during late devonian and early carboniferous times the recognized facies succession reflects a progressive stepwise lowering of the sediment surface through time from a peritidal lagoonal environment to a deep water anoxic basin the frasnian shallow water carbonate platform is represented by lagoonal facies with peritidal sediments small scale deepening upward cycles punctuated with emersion surfaces are a feature of this stage they resulted from a combination and continuous balance between carbonate production subsidence and low order eustatic sea level fluctuations the carbonate platform aggraded at rates around 100 125 m ma the shallow water peritidal carbonates are separated from the post platform deposits by an unconformity surface developed during subaerial exposure the flooding of the faulted block of galezice in the pre late marginifera time and the subsequent initial drowning resulted primarily from a rapid sea level rise small dimension of the seamount and its cemented upper surface were the most important factors that facilitated the sediment removal and thus suppressed the sediment accumulation a condensed section was deposited on the top of the seamount its stratigraphic succession and rare cephalopod storm beds account for a model of redistribution of sediment over the swell disintegrated by small scale faulting during drowning the seamount traversed down through the photic zone at an average rate not higher than 20 25 m ma transformation of the swell into a basin accelerated in the late tournaisian anchoralis zone it is manifested by an increase of deposition rate and by a lithology of alternating limestones and clays with participation of fine grained calciturbidites the associated tephra deposits and syndepositional ferruginous hydrothermal mineralization were the result of extensional tectonics on the facies evolution the drowning was completed in the visean with deposition of black siliceous shales in the starved basin the death of the devonian carbonate platform in the galezice area illustrates well the famed paradox of drowned platforms as the subsidence rate was much slower during the drowning than during the phase of the platform aggradation

assessment of thermal evolution of paleozoic successions of the holy cross mountains poland abstract poland is considered the most prospective country for shale gas production in europe hydrocarbon generation expulsion scenarios drawn in the latest intensive exploration phases tend to overestimate maturation levels when compared with brand new data acquired after recent drillings we tested an integrated workflow to correlate published and original thermal maturity datasets for the paleozoic to jurassic successions cropping out in the holy cross mountains these successions when preserved in subsurface host the major source rocks in the area the application of the workflow allowed us to highlight the burial and thermal evolutionary scenarios of the two tectono stratigraphic blocks of the holy cross mountains ysogory and kielce blocks and to propose this approach as a tool for reducing levels of uncertainty in thermal maturity assessment of paleozoic successions worldwide in particular published datasets including colour alteration indexes of paleozoic microfossils conodont acritarchs and vitrinite and graptolite reflectance data show differences in levels of thermal maturity for the ysogory mid mature to overmature and kielce immature to late mature blocks original data derived from optical analysis pyrolysis and raman spectroscopy on kerogen and x ray diffraction on fine grained sediments mostly confirm and integrate published data distribution 1d thermal models constrained by these data show burial and exhumation events of different magnitude during the late cretaceous for the ysogory maximum burial depths of 9 km and kielce burial depths of 6 km blocks that have been related to the holy cross fault polyphase activity in the end palynomorph darkness index and raman spectroscopy on kerogen for llandoverian and cambrian rocks turned out to be promising tools for assessing thermal maturity of paleozoic organic facies devoid of vitrinite macerals

determination of planetary basalt parentage a simple technique using the electron microprobe many basaltic meteorites are being discovered in old and new meteorite suites including those from cold deserts e g antarctica and hot desert environments it is important to establish the specific planetary body source proven techniques for establishing planetary parentage include stable isotopic signatures especially oxygen certain elemental ratios in bulk samples and certain elemental ratios in specific minerals some of these techniques are expensive require considerable sample preparation and are adversely affected by weathering processes on the parent body or on earth we have been seeking key major and minor elemental ratios in pyroxene olivine and feldspar that can be measured by the electron microprobe on standard thin sections these ratios may be preserved in unweathered portions of mineral grains and thus see through weathering processes in addition if the sample is too small to provide a representative bulk composition it may still have key information recorded in individual minerals we have found that some of the most useful chemical parameters are fe mn atomic in olivine or pyroxene and the percent anorthite an in plagioclase solid solutions a plot of fe mn in pyroxene and or olivine verses an defines compositional fields that are significantly different for earth mars moon 4 vesta and the angrite parent body this method may be especially powerful when combined with oxygen isotope data

oxygen isotopic constraints on the origin of magnesian chondrules and on the gaseous reservoirs in the early solar system abstract we report in situ ion microprobe analyses of the oxygen isotopic composition of the major silicate phases olivine low ca pyroxene silica and mesostasis of 37 magnesian porphyritic type i chondrules from cv vigarano usnm 477 2 vigarano uh5 mokoia and efremovka and cr eet 92042 eet 92147 eet 87770 el djouf 001 mac 87320 and gra 95229 carbonaceous chondrites in spite of significant variations of the modal proportions of major mineral phases in cr and cv chondrules the same isotopic characteristics are observed i olivines are isotopically homogeneous at the level within a chondrule although they may vary significantly from one chondrule to another ii low ca pyroxenes are also isotopically homogeneous but systematically 16o depleted relative to olivines of the same chondrule and iii all chondrule minerals analyzed show 16o enrichments relative to the terrestrial mass fractionation line enrichments that decrease from olivine spinel to low ca pyroxene and to silica and mesostasis the observation that in most of the type i chondrules studied the coexisting olivine and pyroxene crystals and glassy mesostasis have different oxygen isotopic compositions implies that the olivine and pyroxene grains are not co magmatic and that the glassy mesostasis is not the parent liquid of the olivine the 18o and 17o values of pyroxene and olivine appear to be strongly correlated for all the studied cr and cv chondrules according to 18 o pyroxene 0 72 0 16 0 13 18 o olivine 1 21 0 54 0 79 17 o pyroxene 0 81 0 15 0 13 17 o olivine 0 60 1 00 0 95 these correlations are consistent with mass balance of oxygen isotopes calculated in the case of chondrule formation according to the following gas melt mineral reactions mg 2 sio 4 olivine sio 2 melt mg 2 si 2 o 6 pyroxene sio 2 melt sio gas 1 2 o 2 gas these equations imply that 2 3 of the oxygen incorporated by low ca pyroxene during its crystallization in the melt is derived from the dissolution of precursor olivine and 1 3 from the addition of chemical components such as sio from the nebular gas the composition of the nebular gaseous reservoir in which type i cr and cv chondrules formed is determined from the present data set to be 18o gas 3 6 1 and 17o gas 1 8 1 this isotopic composition is in excellent agreement with that of the gaseous reservoir previously inferred from the oxygen isotope systematics of bulk chondrules from various chondrite groups i e cv cr unequilibrated ordinary and eh thus the oxygen isotopic systematic strongly supports the idea that most of the olivines in type i chondrules are relict grains and that gas melt interaction played a major role in the formation of type i chondrules

opaque assemblages in cr2 graves nunataks gra 06100 as indicators of shock driven hydrothermal alteration in the cr chondrite parent body we have studied the petrologic characteristics of sulfide metal lodes polymineralic fe ni nodules and opaque assemblages in the cr2 chondrite graves nunataks gra 06100 one of the most altered cr chondrites unlike low petrologic type cr chondrites alteration of metal appears to have played a central role in the formation of secondary minerals in gra 06100 differences in the mineralogy and chemical compositions of materials in gra 06100 suggest that it experienced higher temperatures than other cr2 chondrites mineralogic features indicative of high temperature include 1 exsolution of ni poor and ni rich metal from nebular kamacite 2 formation of sulfides oxides and phosphates 3 changes in the co ni ratios and 4 carbidization of fe ni metal the conspicuous absence of pentlandite may indicate that peak temperatures exceeded 600 c opaques appear to have been affected by the action of aqueous fluids that resulted in the formation of abundant oxides fe rich carbonates including endmember ankerite and the sulfide silicate phosphate scorzalite we suggest that these materials formed via impact driven metamorphism mineralogic features indicative of impact metamorphism include 1 the presence of sulfide metal lodes 2 the abundance of polymineralic opaque assemblages with mosaic like textures and 3 the presence of suessite initial shock metamorphism probably resulted in replacement of nebular fe ni metal in chondrules and in matrix by ni rich co rich fe metal al ti cr rich alloys and fe sulfides while subsequent hydrothermal alteration produced accessory oxides phosphates and fe carbonates an extensive network of sulfide metal veins permitted effective exchange of siderophile elements from pre existing metal nodules with adjacent chondrules and matrix resulting in unusually high fe contents in these objects

variscan tectonics in the holy cross mountains poland and the role of structural inheritance during alpine tectonics abstract the present study was carried out in the holy cross mountains hcm of south central poland and includes computation of palaeostresses following angelier s method and field structural analysis the palaeozoic basement of the hcm comprises two tectonic units separated by the major wnw ese striking holy cross fault hcf fold analysis indicates a n s to nne ssw direction of variscan shortening micro structures and fold analysis from upper devonian rocks further reveal 1 a brittle tectonic event due to a nw se compression preceding folding that could be related to pre late carboniferous tectonics due to block transport within the tornquist teisseyre zone ttz and 2 polyphase variscan folding comprising a an early stage of n s shortening marked by north verging ramps b a main folding event and axial cleavage formation involving n s to nne ssw shortening and c a late stage of shortening deforming older folds and cleavage a mainly extensional tectonic regime dominated from the permian until the cretaceous during which time the hcf was reactivated as a normal fault large nw se faults bordering the mid polish trough mpt developed subsequent tectonic inversion of the mpt resulted in basin uplift mid polish swell mps palaeostress computations from mesozoic strata suggest a ne sw direction for the main maastrichtian paleocene shortening phase in addition to two minor brittle events resulting from n s and e w compression analysis of local folds in the mesozoic cover indicates a causal relationship with the maastrichtian paleocene reactivation of older faults in particular en echelon folds in the radomsko elevation suggest a sinistral reactivation of the palaeozoic hcf folds in the southwestern part of the hcm argue for reactivation in the reverse mode of a nw se trending fault bordering the mps that originated in the mesozoic in palaeozoic strata post variscan brittle deformation and micro fault reactivation are attributed to the tectonic events of maastrichtian paleocene age reactivation of n s fractures is demonstrated in the rzepka quarry where fractures in devonian dolomites are filled by calcite probably formed during a late variscan event and by younger late permian early triassic sediments they were subsequently reactivated as dextral strike slip faults during the ne sw maastrichtian paleocene compression

the formation and alteration of the renazzo like carbonaceous chondrites iii toward understanding the genesis of ferromagnesian chondrules to better understand the formation conditions of ferromagnesian chondrules from the renazzo like carbonaceous cr chondrites a systematic study of 210 chondrules from 15 cr chondrites was conducted the texture and composition of silicate and opaque minerals from each observed feo rich type ii chondrule and a representative number of feo poor type i chondrules were studied to build a substantial and self consistent data set the average abundances and standard deviations of cr2o3 in feo rich olivine phenocrysts are consistent with previous work that the cr chondrites are among the least thermally altered samples from the early solar system type ii chondrules from the cr chondrites formed under highly variable conditions e g precursor composition redox conditions cooling rate with each chondrule recording a distinct igneous history the opaque minerals within type ii chondrules are consistent with formation during chondrule melting and cooling starting as s and ni rich liquids at 988 1350 c then cooling to form monosulfide solid solution mss that crystallized around olivine pyroxene phenocrysts during cooling fe ni metal crystallized from the s and ni rich liquid and upon further cooling mss decomposed into pentlandite and pyrrhotite with pentlandite exsolving from mss at 400 600 c the composition texture and inferred formation temperature of pentlandite within chondrules studied here is inconsistent with formation via aqueous alteration however some opaque minerals fe ni metal versus magnetite and panethite present in type ii chondrules are a proxy for the degree of whole rock aqueous alteration the texture and composition of sulfide bearing opaque minerals in graves nunataks 06100 and grosvenor mountains 03116 suggest that they are the most thermally altered cr chondrites

tectonic evolution of the mid polish trough modelling implications and significance for central european geology abstract the polish basin forms the easternmost part of the permian mesozoic northwest european basin the depocentral axis of the polish basin the mid polish trough mpt is superimposed on the boundary between the west european phanerozoic and east european proterozoic crustal domains within the trans european suture zone the presence of this fundamental crustal boundary may be paramount in structurally controlling the position of the mpt concentrating stresses during post variscan wrench and extensional tectonics in central europe tectonic subsidence analysis of the preserved and reconstructed stratigraphic record of the polish basin indicates the occurrence of an initial late permian early triassic 255 241 ma rifting phase that was followed by subsequent episodes of increased tectonic subsidence during the oxfordian kimmeridgian 157 152 ma and beginning in the cenomanian 97 ma the oxfordian kimmeridgian episode is interpreted as corresponding to a second extensional event which correlated with intersified rifting and wrench activity within the arctic north atlantic rift system and along the northern tethyan margin while the cenomanian may be considered a precursor of compressional deformations in the basin which culminated in basin inversion in the latest cretaceous and paleocene forward modelling results in view of existing geophysical interpretations which show the presence of a deep moho and a very velocity lower crustal layer beneath thempt suggest that permo mesozoic basic development may be related at least in part to the intrusion of mantle material into and densification of the lower crust rather than exclusively to crustal extension and thinning

palaeoenvironments of the eifelian dolomites with earliest tetrapod trackways holy cross mountains poland abstract the eifelian dolomites in the zachelmie quarry holy cross mountains poland contain trackways and tracks of tetrapods 390 391 ma old and thus the oldest known so far the environments of the trackway bearing beds have been investigated using sedimentological palaeontological geochemical and palaeomagnetic methods the reconstructed tetrapod habitats comprised shallow water lagoons separated from an open marine basin by sparsely vegetated islands and spits the lagoonal waters were well aerated and a few metres deep at most undergoing periodic desiccation the dolomitic sediments primarily of microbial origin formed in tropical waters of slightly modified marine composition oxygen isotope data obtained from the dolomicrites suggest water temperatures around 30 c the seasonal semi arid to sub humid climate deduced from paleosol characteristics was probably of a tropical monsoonal type the degree of restriction of the lagoonal system evolved from relatively open evaporation dominated towards increasingly closed freshwater influenced the detailed observations of the footprint bearing beds as well as the characteristics of the tracks indicate that they were formed mostly under subaqueous conditions by wading walking on the bottom or swimming animals lack of tidal indicators in the restricted zachelmie lagoons argues against previous concept that tidal flats served as a food source for the early tetrapods nor is a hypothesis of flooded woodlands confirmed as a habitat promoting the fish to tetrapod transition we propose that functional limbs emerged among aqueous animals that acquired their locomotional capabilities in a shallow lagoonal water before attempting longer excursions on land

principal characteristics of the upper silesian block and malopolska block border zone southern poland the upper silesian and malopolska blocks are situated near the southwestern boundary of the east european platform within the trans european suture zone the lower palaeozoic lithologies of the blocks reveal different stratigraphic and diastrophic development in the upper silesian block unmetamorphosed and gently folded lower cambrian to ordovician sedimentary rocks rest on a cadomian basement the lower cambrian is represented by an older sub holmia borzeta formation and a younger holmia goczalkowice formation the thickness of the cambrian lithologies increases from the southwest towards the lateral part of the block in the malopolska block palaeozoic and precambrian lithologies are represented by regionally metamorphosed and intensely folded lower cambrian vendian clastic rocks which are unconformably overlain by ordovician lower silurian carbonates and upper silurian clastic rocks the crystalline basement of the malopolska block has yet to be recognized the lower palaeozoic sediments of both blocks are overlain by devonian and carboniferous rocks the blocks are in direct contact along a narrow tectonic zone a part of the largely concealed hamburg krakow fault zone in which tectonic evolution has taken place spasmodically with strike slip movements predominating

intraplate brittle deformation and states of paleostress constrained by fault kinematics in the central german platform abstract the structural evolution of central europe reflects contrasting tectonic regimes after the variscan orogeny during mesozoic cenozoic time the brittle deformation related to each tectonic regime is localized mainly along major fault zones creating complex fracture patterns and kinematics through time with diverging interpretations on the number and succession of the causing events by contrast fracture patterns in less deformed domains often provide a pristine structural inventory we investigate the brittle deformation of a relatively stable wide area of the central german platform using fault slip data to identify the regional stress fields required to satisfy the data in a non classical approach and in order to avoid local stress variations and misinterpretations the fault slip data are scaled up throughout the study area into subsets of consistent kinematics and chronology for sedimentary cover and crystalline basement rocks direct stress tensor inversion was performed through an iterative refining process and the computed stress tensors were verified using field based observations criteria on relative tilt geometry and indicators of kinematic change suggest a succession of events which begins with a post triassic normal faulting regime with 3 axis trending ne sw the deformation then follows by strike slip and thrust faulting regimes with a change of 1 axis from n s to ne sw supposedly in the late cretaceous two younger events are characterized by cenozoic normal and oblique thrust faulting regimes with nw se trending 3 and 1 axes respectively the fracture patterns of both the cover and basement rocks appear to record the same states of stress

the significance of the variscan orogeny in the świetokrzyskie mountains mid polish uplands the wietokrzyski horst created during the laramide phase is situated in the central part of the mid polish uplands it is composed of folded paleozoic rocks partly covered by mesozoic sediments in this area two tectonostratigraphic units can be distinguished the kielce unit to the s and the ysogory unit to the n

fayalitic halos around inclusions in forsterites from carbonaceous chondrites abstract spindle shaped fayalitic halos occur in forsterites of the allende kaba mokoia vigarano and ningqiang carbonaceous chondrites the halos have 1 ellipsoidal or less commonly rounded shapes 2 long axes parallel to each other within given host crystals 3 round bleb like inclusions of ni rich metal and sulfide in their centers and 4 compositional gradients that are most fe rich near the inclusions the fe and mg compositional profiles are well approximated by the error function which in combination with halo shapes indicates a diffusional origin the high ni contents relative to kamacite of the metal inclusions suggest fe loss we propose that the halos formed by oxidation of the fe ni metal in the inclusions and fe 2 diffusion into adjoining forsterite the halo dimensions suggest they formed between 1000 and 1250 k carbonaceous chondrites are characterized by among other features minerals and some organic molecules that are only stable at relatively low temperatures probably less than 500 k and certainly lower than 800 k the conditions required to form the fayalitic halos by diffusion are inconsistent with such low temperatures this combination leads us to conclude that the halos formed prior to their incorporation in the parent body ies of their host meteorites possibilities are that the halos formed in the nebula or within a prior parent body from which material was dispersed and reaggregated

mineralogy and texture of fe ni sulfides in ci1 chondrites clues to the extent of aqueous alteration on the ci1 parent body to better understand the role of aqueous alteration on the ci1 parent body we have analyzed the texture composition and mineral associations of iron nickel sulfides in four of the five known ci1 chondrites the most commonly occurring sulfide present in the ci1 chondrites is the iron deficient fe ni sulfide pyrrhotite fe ni 1 xs that has a composition close to that of stoichiometric troilite fes three of the ci1s alais ivuna and tonk also contain pentlandite fe ni 9s8 although pentlandite is a rare phase in ivuna cubanite cufe2s3 was found in both alais and ivuna in this study although it has also been reported in orgueil macdougall and kerridge 1977 the pyrrhotite grains in all four chondrites form hexagonal rectangular or irregular shapes and show no evidence of ni or co zoning the pyrrhotite grains in orgueil and ivuna are in general smaller and show more corrosions or embayments than those in alais or tonk we suggest that the precursor sulfide present in the ci1 chondrites was troilite which during brecciation and oxidation on the parent body at a temperature of 100 c or less converted the troilite to magnetite and pyrrhotite with pentlandite inclusions subsequently continued alteration on the parent body removed pentlandite partially from alais tonk and ivuna completely from orgueil leaving behind pyrrhotite with spaces corrosions where the pentlandite had been ni derived from the pentlandite was incorporated into ferrihydrite onto the surface of which the ni na sulfate ni bloedite formed based on the size and abundant corrosions within pyrrhotite grains combined with observations from other authors we conclude that orgueil and ivuna have undergone a greater degree of alteration than alais and tonk further work is needed to assess the conditions under which pentlandite would be dissolved preferentially to pyrrhotite as the study of terrestrial literature indicates that the latter mineral is preferentially removed

devonian cretaceous repeated subsidence and uplift along the teisseyre tornquist zone in se poland insight from seismic data interpretation abstract the teisseyre tornquist zone that separates the east european craton from the palaeozoic platform forms one of the most fundamental lithospheric boundaries in europe devonian to cretaceous paleogene evolution of the se segment of this zone was analyzed using high quality seismic reflection data that provided detailed information regarding entire palaeozoic and mesozoic sedimentary cover with particular focus on problems of late carboniferous and late cretaceous paleogene basin inversion and uplift two previously proposed models of development and inversion of the devonian carboniferous lublin basin seem to only partly explain configuration of this sedimentary basin a new model includes late devonian early carboniferous reverse faulting within the cratonic area ne from the kock fault zone possibly first far field effect of the variscan orogeny this was followed by late carboniferous inversion of the lublin basin inversion tectonics was associated with strike slip movements along the ursynow kazimierz fault zone and thrusting along the kock fault zone possibly triggered by deeper strike slip movements late carboniferous inversion related deformations along the ne boundary of the lublin basin were associated with some degree of ductile quasi diapiric deformation facilitated by thick series of silurian shales during mesozoic extension and development of the mid polish trough major fault zones within the lublin basin remained mostly inactive and subsidence centre moved to the sw towards the nowe miasto zawichost fault zone and further to the sw into the present day holy cross mts area late cretaceous paleogene inversion of the mid polish trough and formation of the mid polish swell was associated with reactivation of inherited deeper fault zones and included also some strike slip faulting the study area provides well documented example of the foreland plate within which repeated basin inversion related to compressive transpressive deformations was triggered by active orogenic processes at the plate margin i e variscan or carpathian orogeny and involved important strike slip reactivation of crustal scale inherited fault zones belonging to the teisseyre tornquist zone

karst systems analyzed using borehole logs devonian carbonates of the świetokrzyskie holy cross mountains central poland abstract the methodological assessment of the quality and the usefulness of borehole logs for karst analysis versus the use of data obtained via direct observation is the first objective of this paper the second objective of the paper is to present in the form of a case study regional analysis of karst in devonian carbonates of the wietokrzyskie holy cross mountains south central poland the subjects of the discussion are karst evolution stages karst horizons and their relationship to relief development the analyzed examples sites presented herein where the reliability of borehole data has often been verified by field observations prove that descriptions of borehole logs can be used for karst analysis however borehole log data analysis is subject to many limitations and requires extensive validation the basic condition that has to be met is the explicitness of the descriptions of karst forms in borehole logs the number and the length of logs macro records as well as the number and the size of karst forms micro records are other important factors that affect log interpretation quality nevertheless the principal general advantage of borehole log analysis is the representative nature of the obtained information the formation of karst horizons independent of the lithology and the stratigraphy of the kowala fm in the wietokrzyskie mountains but controlled by external morphological factors suggests an isotropic character of this formation two general vertical types of karst systems are distinguished in this formation 1 karst horizons and 2 extensive karst development without distinct differentiation the former could have been connected with fluvial base levels whereas the latter represents systems formed within the vadose zone

fe mn systematics of type iia chondrules in unequilibrated co cr and ordinary chondrites we have examined fe mn systematics of 34 type iia chondrules in eight highly unequilibrated co cr and ordinary chondrites using new data from this study and prior studies from our laboratory olivine grains from type iia chondrules in co chondrites and unequilibrated ordinary chondrites uoc have significantly different fe mn ratios with mean molar fe mn 99 and 44 respectively olivine analyses from both these chondrite groups show well defined trends in mn versus fe afu and molar fe mn versus fe mg diagrams in general type iia chondrules in cr chondrites have properties intermediate between those in uoc and co chondrites in most uoc and cr type iia chondrules the fe mn ratio of olivine decreases during crystallization whereas in co chondrites the fe mn ratio does not appear to change it is difficult to interpret the observed fe mn trends in terms of differing moderately volatile element depletions inherited from precursor materials instead we suggest that significant differences in the abundances of silicates and sulfides metals in the precursor material as well as open system behavior during chondrule formation were responsible for establishing the different fe mn trends using fe mn mg systematics we are able to identify relict grains in type iia chondrules which could be derived from previous generations of chondrules including chondrules from other chondrite groups and possibly chondritic reservoirs that have not been sampled previously

magnetic susceptibility and selected geochemical mineralogical data as proxies for early to middle frasnian late devonian carbonate depositional settings in the holy cross mountains southern poland abstract the magnetic susceptibility ms and other petromagnetic features of early to middle frasnian carbonates from the holy cross mountains southern poland were studied they were correlated with the eovariscan tectonic activity and palaeoenvironmental changes the ms logs were compared with the available geochemical and mineralogical data a substantial paramagnetic contribution to the ms of the frasnian carbonates is evidenced by a poor correlation of this parameter with the isothermal remanent magnetization values and by a decrease of ms values at low temperatures an estimation of paramagnetic input indicates the dominance of this contribution to the magnetic susceptibility in 60 of studied samples the ms low widely documented in samples through the palmatolepis punctata zone is particularly due to limited input of paramagnetic mineral particles into the basin where also amounts of larger detrital grains of quartz hematite and goethite were significantly reduced this depression corresponds well to anomalously high carbon isotope 13c values for carbonates nevertheless a transient ms rise across the e mf boundary linked with an increase in detrital quartz content suggests together that both the initiation and termination phases of the punctata event indeed coincided with increased terrigenous eolian input from uplifted lands the ms high identified in the lower part of the palmatolepis hassi zone coincides with higher content of detrital quartz hematite and goethite being accompanied by low 13c values in spite of similar ms stratigraphic signatures in other basins the increased detrital input of proximal provenance is likely connected with the first variscan tectonic events that spread over the region and subsequently led to gradual closing of the saxothuringian ocean segments with basement uplift in the area of the mid german crystalline high