decorrelation in interferometric radar echoes a radar interferometric technique for topographic mapping of surfaces implemented utilizing a single synthetic aperture radar sar system in a nearly repeating orbit is discussed the authors characterize the various sources contributing to the echo correlation statistics and isolate the term which most closely describes surficial change they then examine the application of this approach to topographic mapping of vegetated surfaces which may be expected to possess varying backscatter over time it is found that there is decorrelation increasing with time but that digital terrain model generation remains feasible the authors present such a map of a forested area in oregon which also includes some nearly unvegetated lava flows such a technique could provide a global digital terrain map

origin of biotite apatite rich enclaves achala batholith argentina the achala batholith of argentina contains very unusual layered enclaves containing up to 30 apatite and 50 biotite in some layers this modal mineralogy produces bulk rock compositions that cannot represent liquids having as little as 29 sio2 and up to 8 p2o5 nor can the enclaves represent metasedimentary xenoliths because 1 none of the precambrian wall rocks has these compositions 2 none of the metasedimentary xenoliths present within the batholith shows any degree of transition to the mica apatite rich enclaves 3 the compositions and textures in the enclaves are inconsistent with metasediments 4 a geochronological study of zircon from an enclave gives an age of 368 2 ma the exact age of zircons in the granitic host rocks for these reasons we conclude that the enclaves are neither xenoliths of precambrian wall rocks nor restite of a precambrian source the identical age of the enclave and the host granites coupled with textural mineralogical and bulk rock characteristics of the enclaves indicates that the enclaves are magmatic segregations i e cumulates the f rich nature of the stubby shaped apatites and biotites indicates a high f content of the magma parental to the enclaves we infer that the viscosity of the melt was lowered sufficiently to allow cumulates to form in spite of the granitic composition of the melt

the genesis of coal from the viewpoint of coal petrology abstract the genesis of the microscopic constituents of coal macerals and of maceral associations microlithotypes representing various coal facies is discussed in the light of recent advances that have been made in the study of coals and modern peats peat microscopy especially promoted the understanding of humification and biological gelification both of which are decisive for the genesis of huminites vitrinites in brown coals and hard coals respectively microbial activity during peatification has been documented by chemists microbiologists and petrologists and recently by electron microscopical observations in coals this activity leads to the incorporation of lipid substances into the humic matter and later influences the chemical physical and technological properties of vitrinites geochemical gelification transforms the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal in this process the hydrogel brown coal is transformed to the bitumogel bituminous coal coal as a source rock for oil has become an important research subject for coal petrologists and oil exploration the formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to the coalification jumps of the macerals especially liptinites and vitrinites and to the generation of secondary macerals like exsudatinite bitumen and micrinite dead carbon bituminization in coal has been revealed by the use of fluorescence microscopy which also found the presence of new liptinite macerals bituminite fluorinite and exsudatinite and suggests a higher proportion of algal material in coals than was thought earlier the genesis of various types of inertinite macerals will probably become an increasingly important subject of research especially with regard to rank inertinites that seem to attain their high inertinitic reflectance initially during coalification besides the origin of macerals the origin of various coal facies in terms of maceral associations is considered in relation to the palaeogeographic depositional milieu the peat forming vegetation palaeoclimate water and nutrient supply acidity marine and calcareous influence and fire with examples from euramerican carboniferous coals gondwana coals and tertiary brown coals vegetation water and oxygen supply eh conditions are most important for the generation of coal facies vegetation has been reconstructed with the help of palaeobotany including palynology cuticular analysis and wood anatomy in brown coals and with the study of petrified permineralized peats preserved in coal balls the microscopical investigations of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative however the results of palynological and cuticular analyses should be evaluated with caution considering the varying resistance of palynomorphs and cuticles and in the case of palynomorphs their possible extrapaludal origin microscopical studies of modern peats that were derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies especially in brown coals the much disputed origin of brown coal lithotypes is considered in detail for hard coals there seems to be agreement that coal layers rich in vitrites and liptinite poor clarite were deposited in wet forest swamps that microlayered liptinite rich clarites are sub aquatic humic muds and that inertinite rich durites represent oxidized peats the origin of liptinite rich durites is controversial either subaquatic muds or oxidized peats the latter perhaps from raised bogs a recent trend in the literature is the assumption that many if not all mineable coal seams have been deposited in raised bogs under ombrogenous oligotrophic conditions although raised bogs with a dense arborescent vegetation are known from borneo it seems not probable that most seams which were deposited in foredeeps or steadily sinking graben zones are of ombrogenous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for occasional seams but as in modern peats striking changes of coal facies are commonly caused by hydrological events e g inundations as a consequences of crevasses or of fires that burned the peat the origin of the inertinite rich gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub arctic peats is recommended coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite as well as by hydrogen rich vitrinites with a relatively low reflectance and high fluorescence all due to a strong bacterial activity in peats of low acidity proposals for further research are made in the conclusions

flank instability of stromboli volcano aeolian islands southern italy integration of gb insar and geomorphological observations abstract stromboli is characterized by frequent explosions of variable energy and periodically interrupted by more energetic blasts emitting large volumes of material the pressurization of a volatile poor high porphyritic magma column that is gas recharged by the deep seated volatile rich low porphyritic magma precedes such events and produces deformations on the nw flank of the volcano sciara del fuoco by integrating geomorphological observations with long term displacements from ground based interferometric radar since december 2007 we identified two landslides whose movements are strongly related with volcanic activity movement patterns obtained through a novel long term analysis of gb insar data permitted us to hypothesize the type of movement and depth for both landslides furthermore their position allowed us to affirm that the effusive vent formed in 2007 at 400 m a s l was the result of the deflection of a feeder dike caused by landslide fractures thus showing the important role of geomorphological discontinuities in volcanic environments

the famatina complex nw argentina back docking of an island arc or terrane accretion early palaeozoic geodynamics at the western gondwana margin

permanent scatterers analysis for atmospheric correction in ground based sar interferometry ground based synthetic aperture radar gb sar interferometry has already been recognized as a powerful tool complementary or alternative to spaceborne sar interferometry for terrain monitoring and for detecting structural changes in buildings it has been noted that in spite of the very short range compared with the satellite configuration in gb sar measurement the disturbances due to atmospheric effects cannot be neglected either the analysis of the interferometric phases of very coherent points called permanent scatterers pss allows the evaluation of the atmospheric disturbance and the possibility of removing it in this paper the ps analysis is carried out both on a test site facility and on a real campaign citrin valley italy that provided data with a temporal baseline of about ten months

terrane processes at the margins of gondwana the process of terrane accretion is vital to the understanding of the formation of continental crust accretionary orogens affect over half of the globe and have a distinctively different evolution to wilson type orogens it is increasingly evident that accretionary orogenesis has played a significant role in the formation of the continents the pacific margin of gondwana preserves a major orogenic belt termed here the australides which was an active site of terrane accretion from neoproterozoic to late mesozoic times and comparable in scale to the rockies from mexico to alaska or the variscan appalachian orogeny the new zealand sector of this orogenic belt was one of the birthplaces of terrane theory and the australide orogeny overall continues to be an important testing ground for terrane studies this volume summarizes the history and principles of terrane theory and presents 16 new works that review and synthesize the current state of knowledge for the gondwana margin from australia through new zealand and antarctica to south america examining the evolution of the whole gondwana margin through time

fault controlled carboniferous a type magmatism in the proto andean foreland sierras pampeanas argentina geochemical constraints and petrogenesis abstract the intrusion of granitoids into the eastern sierras pampeanas in the early carboniferous took place after a long period of mainly compressional deformation that included the famatinian ordovician and achalian devonian orogenies these granitoids occur as small scattered plutons emplaced in a dominant extensional setting within older metamorphic and igneous rocks and many of them are arranged along a reactivated large shear zone a set of 46 samples from different granitic rocks huaco granitic complex san blas pluton and the la chinchilla stock from the sierra de velasco zapata granitic complex from sierra de zapata and the los arboles pluton from sierra de fiambala display high and restricted sio 2 contents between 69 2 and 76 4 wt on both feo feo mgo vs sio 2 and na 2 o k 2 o cao vs sio 2 plots the samples plot in the ferroan and alkaline calcic to calco alkaline fields feo feo mgo 0 88 1 0 na 2 o k 2 o cao 6 3 8 3 thus showing an a type granitoid signature the high concentrations for the high field strength elements hsfe such as y nb ga ta u th etc and flat ree patterns showing significant negative eu anomalies are also typical features of a type granites our petrogenetic model supports progressive fractional crystallization with dominant fractionation of feldspar and a source mineral assemblage enriched in plagioclase biotites have distinctive compositions with high feo mgo ratios 7 8 61 5 f 360 5610 ppm and cl 120 1050 ppm the feo mgo ratios together with the f and cl content of igneous biotites seem to reflect the nature of their parental host magmas and may be useful in identifying a type granitoids the isotopic data rb sr and sm nd confirm that the a type granites represent variable mixtures of asthenospheric mantle and continental crust and different mixtures lead to different subtypes of a type granite illustrating the lack of consensus about a type magma origin we conclude that prominent shear zones play an important role in providing suitable conduits for ascending asthenospheric material and heat influx in the crust a hypothesis that is in accord with other recent work on a type granites

integrating radar and laser based remote sensing techniques for monitoring structural deformation of archaeological monuments ground based synthetic aperture radar interferometry gbinsar and terrestrial laser scanning tls were purposely integrated to obtain 3d interferometric radar point clouds to facilitate the spatial interpretation of displacements affecting archaeological monuments the paper describes the procedure to implement this integrated approach in the real world situations of surveillance of archaeological and built heritage targeted tests were carried out on the case study of the domus tiberiana sited along the northern side of the palatino hill in the central archaeological area of rome italy and displacements of the monument were monitored over almost one year of acquisition the gbinsar tls integration provided updated information about the condition of the archaeological structures in relation to their history of instability mechanisms and did not highlighted a general worsening for the stability of the entire monument point wise and prompt detection of displacement anomalies and or sudden changes in displacement trends proved the suitability of the method to support early warning procedures also to evaluate effects on the masonry due to human activities

generation of metaluminous a type granites by low pressure melting of calc alkaline granitoids melting experiments on two calc alkaline rocks a tonalite and a granodiorite demonstrate that shallow dehydration melting of hornblende and biotite bearing granitoids generates metaluminous a type granitic melts profuse crystallization of calcic plagioclase orthopyroxene during low pressure p 4 kbar incongruent melting explains all of the major and trace element characteristics of a type granites e g their low al ca mg sr and eu contents and high ga al and k na ratios as well as their common association with anorthositic and mangeritic rocks the residual assemblage produced during melting of the same rocks in the deep crust p 8 kbar is dominated by clinopyroxene and as a consequence most of the chemical features diagnostic of a type granites are lost the high temperatures 900 c and low h 2 o contents 4 wt that are characteristic of a type magmas are adequately explained by the h 2 o poor nature of the granitoid source materials and require neither a granulitic nor a f rich source previous attempts to explain the origin of a type granites have focused on the nature of the source material these experiments show that pressure of melting is at least as important as source composition in engendering a type melts

review and update of the applications of organic petrology part 1 geological applications abstract organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry coal petrology was then considered a branch of coal science later with the development of specialized nomenclature classification of coal components and the standardization and improvement of analytical microscopical methods this discipline expanded in interests and name becoming organic petrology organic petrology carries a broader context being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources at present organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences throughout the 20th century several important monographs have been published on the discipline of organic petrology including stach s textbook of coal petrology 1st edition 1935 2nd 1975 3rd 1982 updated as the more general organic petrology by taylor et al 1998 more recently the text applied coal petrology the role of petrology in coal utilization was published by suarez ruiz and crelling 2008 this review is the first in a two part review series that describes and updates the role of organic petrology in geosciences a second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow

temporal analysis of a landslide by means of a ground based sar interferometer a ground based synthetic aperture radar gb sar interferometer is used to retrieve the velocity field of a landslide high resolution images are obtained by means of a time domain sar processor an in depth analysis of the sequence of sar interferograms enables the recognition of a slowly deforming upper scarp in the scene and a debris flow that feeds the accumulation zone of the landslide where a fast change in terrain morphology is observed the estimated deformation map is in agreement with the available measurements obtained by means of global positioning system receivers results show that gb sar interferometry is a cost effective solution for the monitoring of landslides the proposed method is shown to be a valid complement to space and airborne sar and to the traditional geodetic instruments

can we measure snow depth with gps receivers 1 snow is an important component of the climate system and a critical storage component in the hydrologic cycle however in situ observations of snow distribution are sparse and remotely sensed products are imprecise and only available at a coarse spatial scale gps geodesists have long recognized that snow can affect a gps signal but it has not been shown that a gps receiver placed in a standard geodetic orientation can be used to measure snow depth in this paper it is shown that changes in snow depth can be clearly tracked in the corresponding multipath modulation of the gps signal results for two spring 2009 snowstorms in colorado show strong agreement between gps snow depth estimates field measurements and nearby ultrasonic snow depth sensors because there are hundreds of geodetic gps receivers operating in snowy regions of the u s it is possible that gps receivers installed for plate deformation studies surveying and weather monitoring could be used to also estimate snow depth

early evolution of the proto andean margin of south america from a detailed study of a 500 km transect in the sierras pampeanas central west argentina two pre silurian tectono magmatic episodes are recognized and defined each culminating in micro continental collisions against the proto andean margin of gondwana the pampean orogeny started in early cambrian time with short lived subduction indicated by ca 535 ma calc alkaline granitoids following pampean terrane collision burial to granulite facies conditions ca 9 kbar generated widespread migmatites and ca 520 ma highly peraluminous granites in the eastern sierras pampeanas after brief quiescence a second major episode the famatinian orogeny started with subduction ca 490 ma forming a wide continental arc and ensialic backarc basin this heralded the approach of laurentia to gondwana during which the precordillera terrane separated from the southern appalachian region finally colliding with gondwana in silurian devonian time

retrieval of wet snow by means of multitemporal sar data an algorithm has been developed for mapping wet snow in mountainous terrain using repeat pass synthetic aperture radar sar images as a basis for algorithm development backscattering properties of snow free and snow covered alpine surfaces were investigated using ers sar data and field measurements at test sites in the austrian alps the incidence angle dependence of backscattering derived from sar data is compared with simulations for snow free surfaces and for surfaces covered by dry snow and wet snow significant seasonal changes of backscattering are observed which are mainly caused by variations of the snow liquid water content and of the surface roughness the importance of surface roughness for backscattering of wet snow is demonstrated by a surface roughness experiment the algorithm for mapping wet snow applies change detection using ratios of wet snow versus snow free or dry snow surfaces the main steps include coregistration speckle reduction thresholding of ratio images geocoding and optionally combination of crossing passes to reduce the loss of information due to layover a threshold of 3 db was found to be appropriate for both radarsat and ers sar to separate wet snow from other surfaces postprocessing steps based on historic snow maps or topographic information are used to correct for dry snow areas at high elevations effects of imaging geometry are investigated by comparing ers sar images with a look angle of 19 spl deg and radarsat sar beam mode s7 images with a look angle of 40 spl deg the comparison of snow maps from sar and landsat 5 thematic mapper images shows good agreement in areas of closed snow cover whereas near the snow line sar tends to slightly underestimate the snow extent

structural interplay between plutons during the construction of a batholith cerro aspero batholith sierras de cordoba argentina magnetic fabric patterns and microstructures of granitic rocks provide evidence of structural modifications as a result of the coalescence of two plutons alpa corral and talita during the construction of a large granitic batholith cerro aspero in the sierras pampeanas of cordoba argentina the alpa corral granite is a small and nearly circular pluton while the larger talita pluton displays a marked n s elongation the nw quadrangle of the alpa corral pluton underwent a deformation resulting in foliation trajectories that outline a crescent moon pattern whose inner arc is concordant with the alpa corral talita contact the highest values for the magnetic susceptibility and its anisotropy are concentrated in the coalescence zone between both plutons the magmatic and sub magmatic nature of the microstructures demonstrates that such a deformation was caused by the southward overriding of the largest talita pluton while the alpa corral pluton was not yet fully crystallized rb sr geochronology indicates that this process took place 369g9 ma ago long after the famatinian ordovician to early devonian deformation of the country rocks which confirms a synmagmatic rather than a regional deformational event q 2006 elsevier ltd all rights reserved

partitioning of fluorine and chlorine between biotite and granitic melt experimental calibration at 200 mpa h 2 o experiments from 640 to 680 c 200 mpa h2o at fo2 nno employing a natural f rich vitrophyric rhyolite from spor mountain utah assessed the effect of variable mg 100mg mg mn fe on the partitioning of fluorine and chlorine between biotite bt and melt over this temperature interval bt fluorite quartz is the sole liquidus phase partition coefficients for fluorine between biotite and glass dfbt melt show a strong dependence on the mg of bt dfbt melt varies from 1 5 to 7 2 over the range of mg from 21 to 76 a strong linear correlation between dfbt melt and mg has a slope of 9 4 and extrapolates through the origin i e dfbt melt 0 at mg 0 an annite siderophyllite solid solution in these experiments dclbt melt values 1 to 6 in the same experiments vary inversely with mg the al content of biotite does not vary with the aluminum saturation index asi molar al2o3 alkali and alkaline earth oxides of melt but two exchange mechanisms involving al appear to operate in these micas 1 alvi aliv siiv mgiv and mgiv 2aliv 2siiv iv the effects of other components such as li or other intensive parameters including fo2 have yet to be evaluated systematically at comparable mg of bt however the spor mountain rhyolite yields higher dfbt melt values than an li rich strongly peraluminous melt previously investigated the results indicate that the mg of bt exerts the principal control on halogen partitioning with asi and t as second order variables the experimental partition coefficients compare well with other experimental results but not with most volcanic rocks magmatic bt from most rhyolites records higher dfbt melt due to reequilibration with degassed h2o depleted magma and perhaps with f2o 1 exchange that may accompany oxidation fe3 o fe2 oh 1 this behavior is evident in magmatic biotite from a zoned peraluminous rhyolite complex near morococala bolivia bt is sharply zoned with f rich rims but bt core melt inclusion pairs fall on our experimental curve for dfbt melt these experimental data can be used in part to assess the preservation of magmatic volatile contents in plutonic or volcanic silicic rocks for plutonic rocks the actual f content of melt not a relative activity ratio involving hf species can be reasonably estimated if the mica has not undergone subsolidus reequilibration this information is potentially useful for some shallow level ca poor magmas that are thought to be rich in f e g a and s type granites but do not conserve f well as rocks

using a ground based sar interferometer and a terrestrial laser scanner to monitor a snow covered slope results from an experimental data collection in tyrol austria in this paper we report on an experimental activity aimed at investigating the potential of two terrestrial remote sensing techniques namely ground based sar gb sar interferometry and terrestrial laser scanning in order to retrieve snow depth sd measurements in mountainous regions terrestrial laser scanning is a more consolidated technique based on the measurement of the optical near infrared reflectivity and it is affected by the surface of the snow layer a temporal data sequence allows us to estimate the absolute sd variation recent use of sar interferometry to evaluate snow mass characteristics is based on relating the measured interferometric phase shift to a change in the snow mass interferometric gb sar measurements and terrestrial laser scanner scans were collected together with pointwise conventional measurements of physical snow parameters during the winters of 2005 2006 and 2006 2007 the experiment was carried out in the wattener lizum a high alpine area at about 2000 m elevation north of the main ridge of the austrian alps in tyrol notwithstanding the difficulty of providing both lengthy data record in dry snow conditions and detailed knowledge of the observed snow characteristics the obtained results confirmed the presence of a clearly measurable interferometric phase variation in relation to the growing height of the snow layer a comparison of the sd maps obtained through the two techniques shows differences partly due to the different nature of the two observations

a review of terrestrial radar interferometry for measuring surface change in the geosciences this paper presents a review of the current state of the art in the use of terrestrial radar interferometry for the detection of surface changes related to mass movement different hardware types and acquisition concepts are described which use either real or synthetic aperture for radar image formation we present approaches for data processing procedures paying special attention to the separation of high resolution displacement information from atmospheric phase variations recent case studies are used to illustrate applications in terrestrial radar interferometry for change detection applications range from detection and quantification of very slow moving millimeters to centimeters per year displacements in rock walls from repeat monitoring to rapid processes resulting in fast displacements 50 m yr acquired during single measurement campaigns with durations of only a few hours fast and episodic acting processes such as rockfall and snow avalanches can be assessed qualitatively in the spatial domain by mapping decorrelation caused by those processes a concluding guide to best practice outlines the necessary preconditions that have to be fulfilled for successful application of the technique as well as in areas characterized by rapid decorrelation empirical data from a ku band sensor show the range of temporal decorrelation of different surfaces after more than two years for rock surfaces and after a few seconds to minutes in vegetated areas during windy conditions the examples show that the displacement field can be measured for landslides in dense grassland ice surfaces on flowing glaciers and snowpack creep copyright 2014 john wiley sons ltd

determination of minimum detectable deformation of terrestrial laser scanning based on error entropy model terrestrial laser scanning tls is a widely used remote sensing technique which can produce very dense point cloud data very promptly and is particularly suited for surface deformation monitoring deformation magnitude is typically estimated by comparing tls scans over the same area but at different time epochs of interest however there is an issue related to such a method which is not clear that whether the difference between two successive surveys results from the surface deformation hence it is vital to determine the minimum detectable deformation mdd by a tls device with a given registration and point cloud error level in this paper the mdd is determined based on the computation of the point cloud error entropy the performance of the proposed method is extensively evaluated numerically using simulated plane board deformation point clouds under a range of distances and incidence angles this proposed method was also successfully applied to deformation monitoring of one landslide test site located in the wuhan university of technology the experimental results demonstrate that the theoretical mdd has a good match with the actual deformation and the deformation greater than mdd can be accurately detected by the tls device

lower carboniferous post orogenic granites in central eastern sierra de velasco sierras pampeanas argentina u pb monazite geochronology geochemistry and sr nd isotopes the central eastern part of the sierra de velasco sierras pampeanas nw argentina is formed by the large huaco 40 30 km and sanagasta 25 15 km granite massifs and the small la chinchilla stock 2 2 km the larger granites intrude into ordovician metagranitoids and crosscut devonian mylonitic shear zones whereas the small stock sharply intrudes into the huaco granite the two voluminous granites are biotitic muscovitic and biotitic porphyritic syeno to monzogranites they contain small and rounded tonalitic and quartz dioritic mafic microgranular enclaves the small stock is an equigranular zinnwaldite and fluorite bearing monzogranite the studied granites are silica rich sio2 70 potassium rich k2o 4 ferroan alkali calcic to slightly calk alkalic and moderately to weakly peraluminous a cnk 1 06 1 18 huaco granite 1 01 1 09 sanagasta granite 1 05 1 06 la chinchilla stock they have moderate to strong enrichments in several lil li rb cs and hfs nb ta y th u elements and low sr ba and eu contents u pb monazite age determinations indicate lower carboniferous crystallization ages 350 358 ma for the huaco granite 352 7 1 4 ma for the sanagasta granite and 344 5 1 4 ma for the la chinchilla stock the larger granites have similar nd values between 2 1 and 4 3 whereas the younger stock has higher nd of 0 6 to 1 4 roughly comparable to the values obtained for the carboniferous san blas granite 1 4 to 1 7 located in the north of the sierra the huaco and sanagasta granites have a mainly crustal source but with some participation of a more primitive possibly mantle derived component the main crustal component can be attributed to ordovician peraluminous metagranitoids the la chinchilla stock derives from a more primitive source suggesting an increase with time in the participation of the primitive component during magma genesis the studied granites were generated during a post orogenic period in a within plate setting possibly as a response to the collapse of the previous famatinian orogen extension of the crust and mantle upwelling they are part of the group of middle devonian lower carboniferous granites of the sierras pampeanas the distribution and u pb ages of these granites suggests a northward arc parallel migration of this mainly post orogenic magmatism with time

radar measurements of snow experiment and analysis this paper considers two specific types of experiments conducted to improve the authors understanding of radar backscatter from snow covered ground surfaces the first experiment involves radar backscatter measurements at cand x band of artificial snow of varying depths the relatively simple target characteristics combined with an exhaustive ground truth effort make the results of this experiment especially amenable to comparison with predictions based on theoretical methods for modeling volume scattering media it is shown that both conventional and dense medium radiative transfer models fail to adequately explain the observed results a direct polarimetric inversion approach is described by which the characteristics of the snow medium are extracted from the measured data the second type of experiment examined in this study involves diurnal backscatter measurements that were made contemporaneously with detailed measurements of the snow wetness depth profiles of the observed scene these data are used to evaluate the capability of a recently proposed algorithm for snow wetness retrieval from polarimetric synthetic aperture radar sar measurements which has hithertofore been applied only to data from very complex and extended mountainous terrains

u pb th pb and ar ar geochronology from the southern sierras pampeanas argentina implications for the palaeozoic tectonic evolution of the western gondwana margin

ground based radar interferometry for landslides monitoring atmospheric and instrumental decorrelation sources on experimental data the application of ground based radar interferometry for landslide monitoring is analyzed a case study based on an experimental campaign carried out in italy during 2002 is discussed interferometric data obtained from coherent synthetic aperture radar sar images acquired by means of c band ground based equipment are analyzed the campaign was aimed at retrieving potential terrain movements of a small landslide observed hundreds of meters away critical aspects related to spatial and temporal decorrelation are discussed the use of optical photogrammetry as a technique for evaluating mechanical stability and correcting geometric distortion is presented results also confirmed that the application of ground based radar interferometry can be attractive and effective if the acquired sar images maintain an adequate coherence on different dates

ordovician metamorphism and plutonism in the sierra de quilmes metamorphic complex implications for the tectonic setting of the northern sierras pampeanas nw argentina towards unravelling the geodynamic setting of the northern sierras pampeanas nw argentina we describe the tectono metamorphic and geochronologic evolution of sub greenschist to granulite facies metamorphic sediments granitoid plutons and pegmatites in the ordovician sierra de quilmes metamorphic complex the protoliths of the metasediments are represented by a sequence of turbidites and minor calcsilicate rocks of the neoproterozoic to cambrian puncoviscana formation the metamorphic complex consists of four zones including the 1 chlorite 2 biotite muscovite 3 garnet cordierite sillimanite and 4 orthopyroxene zones zones 3 and 4 show an increasing degree of anatexis reaching large scale diatexis in the orthopyroxene zone at p t conditions exceeding 800 c and 600 mpa at or shortly after the metamorphic peak the granitic to tonalitic cafayate pluton intruded approximately along the boundary between anatectic and non anatectic rocks retrograde near isobaric cooling of the middle crust was accompanied by non penetrative ductile shearing at granulite to amphibolite facies p t conditions evidence for significant prograde deformation is absent in the sierra de quilmes metamorphic complex monazite and titanite u pb isotopic data constrain the metamorphic peak in migmatites and calcsilicate rocks to be at or slightly prior to 470 ma retrograde amphibolite facies mineral reactions led to continuous formation of monazite and titanite during slow cooling between 470 ma and 455 ma u pb data the composite cafayate pluton intruded over a time interval of several million years between 477 ma sm nd isochron and 460 ma monazite and titanite u pb isochron followed by pegmatites a younger group of pegmatites was emplaced in the country rocks at the end of the ordovician 440 ma rb sr mineral isochrons postdating most of the retrograde shear zones resetting of the muscovite k ar and 40ar 39ar system in weakly deformed pegmatites and crystallisation of new muscovite in low grade metamorphic sediments at 400 416 ma is attributed to minor late greenschist and sub greenschist facies metamorphism and deformation the massive early ordovician heat transfer the absence of major prograde deformation and subsequent prolonged phases of non penetrative deformation in the high grade metamorphic zones during slow near isobaric cooling contradict crustal thickening and continent collision models as have been proposed for the southern sierras pampeanas we suggest continuous or stepwise extensional tectonics in a back arc or a mobile belt tectonic environment for the ordovician sierra de quilmes and the northern sierras pampeanas in general an extensional setting of the northern sierras pampeanas in the ordovician is in agreement with the coeval formation of marine extensional sediment basins in vicinity of the sierras pampeanas in northwestern argentina and southern bolivia

the las chacras potrerillos batholith pampean ranges argentina structural evidences emplacement and timing of the intrusion within the southern part of the sierra pampeanas the sierra de san luis argentina a series of extensive intrusive bodies are regarded to post date the famatinian cycle but were emplaced during the achalian a period of heterogeneous deformation along crustal scale fault zones the largest of those is the las chacras potrerillos batholith that is situated at the northern end of the transpressive sinistral guzman shear zone this composite pluton exhibits three sub domains that comprise two granitoid sub units each the southern potrerillos stock muscovite bearing red granite and biotite bearing red granite and the central biotite porphyritic granite and giant porphyritic granite and northern domain equigranular granite and porphyritic granite of the las chacras stock the crystallisation ages of the biotite porphyritic granite is around 381 ma u pb on zircons and pb pb on sphene while the host rock was already cooled below 350 c at 420 ma thermal modelling approaches favour a pulsed intrusion with a duration of 1 5 ma the emplacement was followed by rapid cooling below the muscovite cooling temperature biotite cooling ages in different sub units reflect either a long lasting cooling history of approximately 30 ma which is supported by the modelling or a reheating effect at around 350 ma devonian age determinations on the fault rocks and granitoids point to a syn tectonic emplacement of the batholith the pluton is interpreted to be positioned at the crossover of sinistral shear zones the origin of this nne directed extensional setting in a transpressive regime seems to be related to the transfer of displacement along a secondary set of nnw trending sinistral faults the final emplacement is due to a subsequent ballooning of the batholith following the direction of space creation this model is based on the relative timing of the emplacement sequence and macroscopically visible planar fabrics in the field as well as magnetic fabric data our results indicate that the emplacement is syn kinematic with respect to the achalian deformation event

insar for estimation of changes in snow water equivalent of dry snow this paper describes the theoretical relation between interferometric phase and changes in snow water equivalent swe and show results from experiments using ers 1 2 tandem data the main scattering contribution from a dry snow cover is from the snow ground interface however the radar wave will be refracted in the snow thus only small changes in the snow properties between two interferometric synthetic aperture radar sar images will change the interferometric phase this phase change is shown to introduce a significantly increase in the digital elevation model dem height error although no effects are observed on the degree of coherence the phase change is also shown to affect the differential interferometric results and may wrongly be interpreted as range displacement the presented theory and results implies that light snowfall and or small changes in snow properties between interferometric sar insar image acquisitions may introduce significant height errors in dem derived from glaciers ice sheets or bare ground even in the case of high degree of coherence thus meteorological observations in addition to degree of coherence must be considered when generating dem in areas covered with snow or where snow fall is likely to have occurred

the proto andean margin of gondwana an introduction a basic background is presented for the discussion of the early palaeozoic geology of western argentina covered by this book this includes the definition and terminology of orogenic cycles on this part of the gondwana margin represented by the eastern sierras pampeanas the pampean orogeny early cambrian relates to an intense but short lived period of terrane collision predating the rifting of the precordillera terrane from laurentia the famatinian cycle is predominantly represented by intense subductionrelated magmatism of early middle ordovician age developed on the continental margin of gondwana during the rifting and drifting of the precordillera terrane the grenvillian basement of the latter is further exemplified by a new rb sr whole rock isochron age of 1021 12 ma for orthogneisses from the western sierras pampeanas a mid ordovician granite in this area dated at 481 6 ma by u pb ion microprobe data may be related to rifting while the precordillera terrane was still attached to laurentia a divergence of opinion is pointed out between some authors in this book who favour mid ordovician collision of the precordillera with gondwana and others who place it much latter in silurian or devonian times

experimental determination of crystal melt partitioning of ga and ge in the system forsterite anorthite diopside the crystal liquid partitioning of ga and ge has been measured experimentally between forsterite diopside anorthite and spinel and melts in the pseudoternary system forsterite anorthite diopside at one atmosphere pressure and 1300 c gallium is incompatible with forsterite and diopside d ga 0 024 and 0 19 respectively is only slightly incompatible in anorthite d ga 0 86 and is highly compatible in spinel d ga 4 6 the partition coefficient for ge is within a factor of two of unity for forsterite diopside and anorthite d ge 0 62 1 4 and 0 51 respectively but ge is incompatible in spinel d ge 0 1 the coefficients for the exchange of ga and al and the exchange of ge and si between minerals and melts generally are within a factor of two of unity as is expected from the geochemical coherence of these element pairs in natural samples the application of our results to the interpretation of natural basaltic and mantle samples from the earth and basalts from the moon and the shergottite parent body demonstrates that it is possible to discriminate between different mantle source compositions using ga al and ge si ratios the ge variation among lunar mare basalts may be indicative of a heterogeneous lunar mantle the substantial depletion of ge in chassigny relative to the other snc meteorites may be evidence of either a heterogeneous shergottite parent body spb mantle or of different geochemical behavior for ge in the spb