structure emplacement and tectonic setting of late devonian granitoid plutons in the tepla barrandian unit bohemian massif the st novice and cista granodiorite tonalite plutons are small 27 and 38 km2 respectively intrusions that are largely discordant to regional ductile structures in the center of the upper crustal tepla barrandian unit bohemian massif their whole rock and trace element compositions are consistent with medium k calc alkaline magma generated above a subducted slab in a continental margin arc setting the u pb zircon age of the st novice pluton newly determined at 375 2 ma using the laser ablation icp ms technique is within the error of the previously published pb pb age of 373 1 ma for the cista pluton the two plutons also share other characteristics that are typical of concentrically expanded plutons ceps such as elliptical cross section in plan view steep contacts inferred downward narrowing conical shape faint normal zoning and margin parallel magmatic foliation decoupled from the regional host rock structures we interpret the st novice and cista plutons as representing the initial late devonian stage of much more voluminous early carboniferous arc related plutonism represented most typically by the central bohemian plutonic complex in the upper crust of the central bohemian massif these two plutons are important tectonic elements in that they indicate an overall shift of the arc related plutonic activity from the nw to the se accompanied with a general compositional trend of the magmas from medium k calc alkaline to shoshonitic ultrapotassic such a pattern is compatible with se directed subduction of the saxothuringian ocean beneath the tepla barrandian overriding plate as a cause of arc related magmatism in this part of the bohemian massif

convective momentum transport associated with the madden julian oscillation based on a reanalysis dataset abstracta better understanding of multiscale interactions within the madden julian oscillation mjo including momentum exchanges is critical for improved mjo prediction skill in this study convective momentum transport cmt associated with the mjo is analyzed based on the noaa climate forecast system reanalysis cfsr a three layer vertical structure associated with the mjo as previously suggested in the mesoscale momentum tendency profile based on global cloud resolving model simulations is evident in the subgrid scale momentum tendency from the cfsr positive negative subgrid scale momentum tendency anomalies are found near the surface negative positive anomalies are found in the low to midtroposphere and positive negative anomalies in the upper troposphere are found within and to the west east of the mjo convection this tends to damp the mjo circulation in the free atmosphere while enhancing mjo winds near the surface in addition it could also reduce the mjo eastward propagation

quasi geostrophic dynamics in the presence of moisture gradients the derivation of a quasi geostrophic system from the rotating shallow water equations on a midlatitude plane coupled with moisture is presented condensation is prescribed to occur whenever the moisture at a point exceeds a prescribed saturation value it is seen that a slow condensation time scale is required to obtain a consistent set of equations at leading order further since the advecting wind fields are geostrophic changes in moisture and hence precipitation occur only via non divergent mechanisms following observations a saturation profile with gradients in the zonal and meridional directions is prescribed a purely meridional gradient has the effect of slowing down the dry rossby waves through a reduction in the equivalent gradient of the background potential vorticity a large scale unstable moist mode results on the inclusion of a zonal gradient by itself or in conjunction with a meridional moisture gradient for gradients that are are representative of the atmosphere the most unstable moist mode propagates zonally in the direction of increasing moisture matures over an intraseasonal time scale and has small phase speed

eastward propagating intraseasonal oscillation represented by chikira sugiyama cumulus parameterization part ii understanding moisture variation under weak temperature gradient balance abstractthe eastward propagating intraseasonal oscillation represented by the chikira sugiyama cumulus scheme in a general circulation model was investigated focusing on the variation of the free tropospheric humidity the net effect of the vertical advection and cloud process amplifies the positive moisture anomaly in the mature phase supporting the moisture mode theory the horizontal advection causes the eastward propagation of the field the variation of the moisture profile is accurately understood by using environmental vertical velocity outside cumuli the velocity is regulated by a thermodynamic balance under a weak temperature gradient a nondimensional parameter plays an important role in the moisture variation which characterizes the efficiency of moistening drying induced by external heating cooling in the middle and lower troposphere the major moistening factor is the radiative warming anomaly which induces the upward environmental vertical velocity anomaly the reevaporation of th

laboratory measurements of elastic anisotropy parameters for the exposed crustal rocks from the hidaka metamorphic belt central hokkaido japan summary to study crustal rock seismic anisotropy and its effect on seismic wave propagation we measure the seismic velocity anisotropy of two amphibolites one biotite gneiss and one biotite schist from the hidaka metamorphic belt in central hokkaido japan under confining pressures up to 150 mpa the rock microstructures show foliation and lineation characterized by lattice preferred orientation lpo of hornblende or biotite p and two s wave velocities are measured along the direction perpendicular to the foliation plane and two directions in the foliation plane perpendicular and parallel to the lineation we assume orthorhombic symmetry based on the rock microstructures and obtain tsvankin s anisotropic parameters an extension of thomsen s parameters for orthorhombic symmetry p and s wave phase velocity surfaces are calculated from anisotropy parameters and compared with the measured velocities along particular directions and with the velocity contour maps calculated from the voigt averages of singlecrystal elastic constants based on the orientation of measured lpo data qualitatively the measured velocity anisotropy agrees with the velocity contour calculated from the lpo data although large quantitative differences exist between them all anisotropy patterns can be approximated as transverse isotropy or its modification appearing as orthorhombic symmetry biotite schist containing 30 per cent volume ratio biotite shows strong s wave anisotropy and the phase velocity surfaces of p waves show a large deviation from ellipticity in the plane perpendicular to the foliation and parallel to the lineation in the same plane s waves show a singularity due to a large bulge of the sv velocity surface

an idealized semi empirical framework for modeling the madden julian oscillation abstractthe authors present a simple semi empirical model to explore the hypothesis that the madden julian oscillation can be represented as a moisture mode destabilized by surface flux and cloud radiative feedbacks the model is one dimensional in longitude the vertical and meridional structure is entirely implicit the only prognostic variable is column water vapor w the zonal wind field is an instantaneous diagnostic function of the precipitation field the linearized version of the model has only westward propagating relative to the mean flow unstable modes because wind induced surface latent heat flux anomalies occur to the west of precipitation anomalies the maximum growth rate occurs at the wavelength at which the correlation between precipitation and surface latent heat flux is maximized this wavelength lies in the synoptic to planetary scale range and is proportional to the horizontal scale associated with the assumed diagnostic wind response to precipitation anomalies the nonlinear version

late precambrian thrust and wrench zones in northern brittany france abstract brioverian units of northern brittany armorican massif france were deformed and metamorphosed during a late precambrian tectonic episode the cadomian orogeny kinematic study strain and displacement in the st cast st brieuc area shows that this tectonic episode was characterized by the obduction of a back arc basin over a continental margin around 580 590 ma ago strain pattern analysis reveals a constant interaction between ssw directed imbricated thrust zones and ductile sinistral wrench zones trending n 50 e the arcuate pattern of cadomian structures in this area results from such an interaction thickening as a result of the thrusts induced migmatization and the development of a high temperature belt around 540 ma in the st malo guingamp area

a unified moisture mode framework for seasonality of the madden julian oscillation abstractthe madden julian oscillation mjo exhibits pronounced seasonality while it is largely characterized by equatorially eastward propagation during the boreal winter mjo convection undergoes marked poleward movement over the asian monsoon region during summer producing a significant modulation of monsoon rainfall in classical mjo theories that seek to interpret the distinct seasonality in mjo propagation features the role of equatorial wave dynamics has been emphasized for its eastward propagation whereas coupling between mjo convection and the mean monsoon flow is considered essential for its northward propagation in this study a unified physical framework based on the moisture mode theory is offered to explain the seasonality in mjo propagation moistening and drying caused by horizontal advection of the lower tropospheric mean moisture by mjo winds which was recently found to be critical for the eastward propagation of the winter mjo is also shown to play a dominant role in operating t

intraseasonal variability in a cloud permitting near global equatorial aquaplanet model abstractrecent studies have suggested that the madden julian oscillation is a result of an instability driven mainly by cloud radiation feedbacks similar in character to self aggregation of convec

omphacite fabric variation in the cabo ortegal eclogite nw spain relationships with strain symmetry during high pressure deformation petrostructural study of cabo ortegal eclogite tectonites provides an insight into the relationships between omphacite lattice preferred orientation and the fundamental deformation parameters in particular strain symmetry microstructural evidence is consistent with a tectonic origin of eclogite fabrics by coeval pyroxene plastic deformation and recrystallization under eclogite facies metamorphic conditions omphacite shape fabrics and garnet spatial distributions are anisotropic and representative of the fields of either apparent flattening or constriction omphacite lattice preferred orientations are dominated by 010 axis maxima normal to the foliation s type or flattening fabrics by 001 axis maxima parallel to the lineation l type or constriction or correspond to other fabric patterns described in the literature omphacite crystallographic fabrics are consistently asymmetric with respect to the structural framework defined by foliation and lineation this suggests that non coaxial deformation components either simple or general shear accompanied eclogite fabric development in addition to any flattening or constriction strain paths and permit shear sense determination these petrostructural features were acquired in the course of eo hercynian ductile deformation probably during deep subduction under 1 5 1 7 gpa confining pressure temperatures above 600 700 c low differential stress 15 20 mpa and slow strain rate 10 12 10 15s 1

mjo propagation shaped by zonal asymmetric structures results from 24 gcm simulations abstracteastward propagation is an essential characteristic of the madden julian oscillation mjo yet simulation of mjo propagation in general circulation models gcms remains a major challenge and understanding the causes of propagation remains controversial the present study explores why the gcms have diverse performances in mjo simulation by diagnosis of 24 gcm simulations an intrinsic linkage is found between mjo propagation and the zonal structural asymmetry with respect to the mjo convective center the observed and realistically simulated mjo eastward propagations are characterized by stronger kelvin easterly waves than rossby westerly waves in the lower troposphere which is opposite to the gill pattern where rossby westerly waves are 2 times stronger than kelvin easterly waves the gcms simulating stronger rossby westerly waves tend to show a stationary mjo mjo propagation performances are robustly correlated with the quality of simulated zonal asymmetries in the 850 hpa equatorial zonal w

a comparison of mineral grain fabrics and finite strain in amphibolites from eastern finland fabrics in amphibolite rocks from the kuopio area eastern finland are described and compared with results of finite strain analysis the area consists of mantled gneiss domes which are deep seated diapiric structures results concern the cover rocks of the domes strain ellipsoids range in shape from prolate to oblate 0 67 v 0 52 strain intensities vary strongly preferred orientations of hornblende have been measured by x ray texture goniometry and corresponding fabric ellipsoids calculated using an eigenvalue method the same has been done for biotite where present fabric ellipsoids obtained for biotite are all oblate 0 04 vf 0 76 those obtained for hornblende range from prolate to oblate 0 60 vf 0 73 intensities of hornblende fabric are weaker than those of biotite fabric local variations of results are induced by grain scale factors such as grain size or original fabrics no simple correlation is found between intensities of fabric and strain in general increasing stra

passive rotation of hematite during deformation a comparison of simulated and natural redbeds fabrics abstract a simulation model is used to generate pole figures assuming strain induced passive rotation of hematite crystals comparison of simulated and natural hematite fabrics allows us to distinguish between dominant passive rotation and other grain scale deformation mechanisms two natural examples are discussed redbeds from the french maritime alps and pyrenean redbeds fabrics indicate that passive rotation is the dominant reorientation mechanism of primary hematite grains during progressive deformation of redbeds

change in dominant mechanisms for phyllosilicate preferred orientation during cleavage development in the kitakami slates of ne japan abstract selected slates from the kitakami mountains of ne japan were studied by means of finite strain measurement x ray texture goniometry optical microscopy back scattered sem and x ray fluorescence and diffraction analyses finite strain recorded by radiolarians in slates although not equivalent to bulk strain shows a positive correlation with strength of phyllosilicate basal plane fabrics however there is a possible difference between the fabric pattern and radiolarian strain ellipsoid shape as well as a difference in fabric pattern between chlorite and illite mica these relationships between phyllosilicate fabrics and finite strains suggest that strain estimation from phyllosilicate fabrics based on the march model may be unreliable unless their relationship is established in each case optical and back scattered sem studies revealed a change in microstructures in accordance with increasing fabric strength in slates with weak fabric strength cleavage domains are dark to opaque in appearance and characterized by a concentration of insoluble residues such as carbonaceous matter sphene ilmenite rutile epidote and apatite as well as phyllosilicates phyllosilicates in cleavage domains are oriented subparallel to cleavage whereas those in intercleavage domains are variously oriented as fabric strength increases cleavage domains become transparent and composed mainly of phyllosilicates phyllosilicates become finer grained and more uniform in grain size they are well oriented in both cleavage and intercleavage domains as fabric strength further increases phyllosilicates tend to coarsen these lines of microstructural evidence suggest that the dominant mechanism for phyllosilicate preferred orientation changes as cleavage develops from pressure solution transfer through syntectonic crystallization recrystallization and possibly to oriented grain growth because fabric strength increases with increasing illite crystallinity metamorphic grade mainly temperature must be one of the major factors which control the dominance of phyllosilicate preferred orientation mechanisms

the relationship of strain and preferred orientation of phyllosilicate grains in rocks a review abstract the calculation of strain from the preferred orientation of platy phyllosilicate grains taking strain to be homogeneous is surprisingly often successful from a pragmatic point of view although numerous theoretical objections to this procedure can be and have been raised for the calculation to succeed the original distribution of mica or clay mineral grains must be known or assumed the usual assumption that the starting distribution was random and therefore nearly uniform implies that the strain history of pelitic sediments is taken to start when the watery sediment was last stirred by waves or bioturbation or if it was laid down in still anoxic waters from the moment of first deposition it therefore includes compaction as part of the strain history which is usually neglected by structural geologists originally random distribution of clay flake orientations has been observed in recently deposited sediments in many instances and has been theoretically explained in various ways exceptions probably exist but their frequency has not been estimated biologically disturbed sediments may be brought nearer to a state of random orientation of clay flakes than they were at deposition with the exception of whole beds or concretions in which pores are early filled with cement mudrocks are almost always compacted by the weight of later deposits the strain so induced is axially symmetric about the vertical and thus about the pole of the bedding planes compaction acts on soft unconsolidated rocks but may continue with increasing overburden on rocks strengthened by cementation and by increasing interlocking of grains tectonic deformation may start early before the rock is fully compacted or it may begin only much later and the mechanisms of deformation increase in complexity with the increasing temperature and hydrostatic stress of deeper burial up to a certain level of mild metamorphism however phyllosilicate grains seem to be rather permanent if not as mineral species then at least by preservation of their constituent sheets of silica tetrahedra given this permanence the mechanisms of rock deformation whether intergranular slip cataclasis or dissolution and reprecipitation and various intragranular processes in the non phyllosilicate matrix hardly matter as far as the recording of strain is concerned even a certain amount of stress solution at especially heavily loaded points of the phyllosilicate grains themselves does not destroy their value as strain markers as long as the dissolved material is disposed of mainly by crystallographically continuous overgrowth on existing grains the same holds for local dissolution of phyllosilicates in portions of old grains that have become thermodynamically unstable by bending widespread irregular or random nucleation and growth of newly nucleated phyllosilicate grains at intermediate or high grades of metamorphism can reduce the reliability of the strain record and so can domainal structure of the deformed rock if both the volume fraction of phyllosilicate grains and the intensity of total strain differ sharply from one domain to another if distinct domains are not equant and have themselves a strong preferred orientation of shape nevertheless rocks containing an anastomosing network of zones rich in phyllosilicate grains as slates and other deformed mudrocks commonly do have in many cases been found to have average preferred orientations of mica or chlorite which if used to estimate the strain give results similar to those obtained from independent strain markers in the same rocks thus the most significant verification of the usefulness of strain estimates by measurement of preferred orientation is the mutual confirmation with independently determined strain the limit to such verification is the rarity of strain markers so that the coexistence of two independent ones is exceptionally rare for this reason however it is important to make full use of the orientation of phyllosilicate grains where they are available the alternative to have no strain measurements at all causes structural geologists to miss potential information

eastward propagating intraseasonal oscillation represented by chikira sugiyama cumulus parameterization part i comparison with observation and reanalysis abstractthe eastward propagating intraseasonal oscillation represented by the chikira sugiyama cumulus parameterization in an atmospheric general circulation model is compared with observations and reanalyses the scheme is characterized by state dependent entrainment rates that vertically vary affected by the environment the zonal wavenumber frequency power spectrum shows a strong signal corresponding to the madden julian oscillation the eastward propagating feature of the convective region and accompanying anomalous zonal wind structure is well extracted by the first and second modes of the combined empirical orthogonal function ceof with a reasonable explained variance for the first mode though the second mode is not sufficiently reproduced the basic features of the composited anomalous fields including moisture temperature and vertical and zonal winds resemble those of the reanalysis in both the free troposphere and surface air the anomalous free tropospheric moisture exhibits its westward ti

evaluating mjo event initiation and decay in the skeleton model using an rmm like index the madden julian oscillation mjo skeleton model is a low order dynamic model that is capable of simulating many of the observed features of the mjo this study develops a model based mjo index that is similar to the well known real time multivariate mjo rmm index to better facilitate comparison between the skeleton model and observational data multivariate and univariate empirical orthogonal function eof analyses were performed on the convective heating and zonal wind data taken from the skeleton model for simulations forced with an idealized warm pool and observed sea surface temperatures ssts the leading eof modes indicated a wave number 1 convectively coupled circulation anomaly with zonal asymmetries that closely resembled the observed rmm eofs especially when the model was forced with observed ssts the rmm like index was used to compute an mjo climatology and document the occurrence of primary continuing and terminating mjo events in the skeleton model the overall amount of mjo activity and event lengths compared reasonably well to observations for such a simple model attempts at reconciling the observed geographic distribution of individual mjo initiation and termination events were not successful for the stochastic simulations though stochasticity is necessary in order to produce composite mjos that initiate and decay with time scales similar to observations finally analysis indicates that the existence of slow moving eastward traveling waves with higher wave numbers k 12 embedded within the large scale flow often precedes mjo termination in the skeleton model

the mantled gneiss domes of kuopio finland interfering diapirs abstract finite strain data from the kuopio mantled gneiss domes are described synclines located between two domes have flattening type strains while those situated between more than two domes exhibit constrictional strains cleavage trajectory patterns show that cleavage tends to parallel the dome boundaries and encloses characteristic points termed cleavage triple points at junctions of synclines the stretching lineation is generally steeply plunging in a mean southwest direction folds range from inclined to reclined their asymmetry is apparently related to irregularities in the cover basement boundary two shear components of the deformation have been deduced from available data the major one is steeply plunging and is well exhibited by cleavage fans steeply plunging lineations and finite strain gradients the second shear component is horizontal as deduced from asymmetric folds and other small scale structures and is controlled by bosses and dimples in the cover basement boundaries the described structural features are explained in terms of interference between progressively inflating neighbouring diapirs furthermore some of these features such as cleavage triple points flattening between two domes and constriction between three or more domes and horizontal shear components controlled by cover basement boundary irregularities could be used as criteria of diapirism a model of progressive dome interference is presented in which each dome inflates and interacts with neighbours such a model could possibly be applied to other orogenic situations with closely spaced diapirs e g archean greenstone belts or granite rich orogenic belts

key processes for the eastward propagation of the madden julian oscillation based on multimodel simulations as a prominent climate variability mode with widespread influences on global weather extremes the madden julian oscillation mjo remains poorly represented in the latest generation of general circulation models gcms with a particular challenge in simulating its eastward propagating convective signals in this study by analyzing multi model simulations from a recent global mjo model evaluation project an effort is made to identify key processes for the eastward propagation of the mjo through analyses of moisture entropy me processes under a moisture mode framework for the mjo the column integrated horizontal me advection is found to play a critical role for the eastward propagation of the mjo in both observations and good mjo models with a primary contribution through advection of the lower tropospheric seasonal mean me by the mjo anomalous circulations by contrast the horizontal me advection effect for the eastward propagation is greatly underestimated in poor mjo gcms due to model deficiencies in simulating both the seasonal mean me pattern and mjo circulations leading to a largely stationary mjo mode in these gcms these results thus pinpoint an important guidance towards improved representation of the mjo in climate and weather forecast models while this study mainly focuses on fundamental physics for the mjo propagation over the indian ocean complex influences by the maritime continent on the mjo and also me processes associated with the mjo over the western pacific warrant further investigations

development of shape and lattice preferred orientations application to the seismic anisotropy of the lower crust abstract we review the physical basis of the development of fabrics in plastic and viscous flow and illustrate the typical fabrics formed by these processes in the main rock forming silicates of the lower crust feldspar quartz pyroxene and amphibole the orientation process in plastic deformation where a single slip is dominant is recalled and the role of the constraint of neighbouring grains is emphasized the fabric development of anisometric crystals in viscous flow is discussed as a function of the main controlling parameters shear strain aspect ratio and interference between crystals the same sense of fabric asymmetry is introduced by plastic and viscous flow between the flow plane and the shape preferred orientation and hence coherent kinematic analysis can be undertaken in both modes of flow in order to assess the role of such fabrics in the seismic laminations of the lower continental crust we have calculated the seismic p wave properties of typical fabrics for hypothetical monomineralic and polymineralic rocks the calculations show that the strongest anisotropies develop in monomineralic rock with values between 5 and 16 compared with 5 and 8 for typical rock compositions the strongest anisotropies for layered monomineralic rocks generated by fabrics is only 6 compared to the 14 suggested by model studies of the observed seismic laminations we suggest that other effects such as compositional layering and or constructive interference of seismic waves are responsible for augmenting the apparent anisotropy

the role of global circumnavigating mode in the mjo initiation and propagation a series of convection permitting regional model simulations are used to study the influences of intraseasonal forcings from the periphery of the tropical indian ocean on the october 2011 mjo event well observed during the dynamics of the madden julian oscillation dynamo field campaign these sensitivity experiments demonstrate the predominant role of a global circumnavigating mode in the initiation and propagation of this mjo event although the regional framework would not completely rule out influences from the extratropics through the western boundary of the model domain it is found that filtering out intraseasonal forcing leads to the absence of kelvin waves which may reduce moisture transport and weakened lower level convergence at the leading edge of the westerlies and further leads to diminishing mjo signatures in these sensitivity experiments meanwhile for the same regional domain initiated two weeks before the onset of the mjo convection there is little impact of whether or not the global mjo signals retained in the initial conditions on the other hand the removal of the global mjo signals from the lateral boundary conditions will not affect the propagation of the mjo after it has been initiated in the regional model domain

quantitative texture analysis of glaucophanite deformed under eclogite facies conditions sesia lanzo zone western alps comparison between x ray and neutron diffraction analysis

causal evidence that rotational moisture advection is critical to the superparameterized madden julian oscillation abstractthe authors investigate the hypothesis that horizontal moisture advection is critical to the eastward propagation of the madden julian oscillation mjo consistent diagnostic evidence has been found in recent mjo permitting global models viewed from the moisture mode dynamical paradigm to test this idea in a causal sense tropical moisture advection by vorticity anomalies is artificially modulated in a superparameterized global model known to produce a realistic mjo signal boosting horizontal moisture advection by tropical vorticity anomalies accelerates and amplifies the simulated mjo in tandem with reduced environmental gross moist stability limiting rotational horizontal moisture advection shuts the mjo down these sensitivities are robust in that they are nearly monotonic with respect to the control parameter and emerge despite basic state sensitivities favoring the opposite response speedup confirms what several diagnostic lines of evidence already suggest that anomalous moisture advecti

a new variscan deformation map of england and wales collections of bedding orientations from subareas of 550 km 2 are used to define bedding fabrics from the variscan fold belt and foreland in england and wales the bedding fabrics constructed from data taken from published geological maps 1 50 000 scale are analysed in terms of the scheidegger watson orientation tensor the calculated eigenvalues of the orientation tensor define the average structural trends including the best fit fold axis for each subarea the eigenvectors of the tensor allow the original sedimentary fabrics to be distinguished from those modified by deformation the progressive tectonic modification of these fabrics leads to the concept of fabric evolution paths and the extent of the modification is expressed by a deformation parameter although it is emphasised that this parameter is not solely a function of finite strain magnitude its variation is represented on a map which brings out different degrees of variscan tectonic modification of bedding fabrics this map delineates a variscan bedding fabric front corresponding to the northern boundary of a zone of pervasive and strong deformation in the foreland this new analysis allows the variation of variscan trends to be mapped and the significance of these trends to be quantified in terms of deformation magnitude 1999 elsevier science b v all rights reserved

three dimensional structure and evolution of the moisture field in the mjo abstractthe large scale circulation features that determine the structure and evolution of mjo related moisture and precipitation fields are examined using a linear analysis protocol based on daily 850 minus 150 hpa global velocity potential data the analysis is augmented by a compositing procedure that emphasizes the structural features over the indo pacific warm pool sector 60 e 180 that give rise to the eastward propagation of the enhanced moisture and precipitation it is found that boundary layer bl convergence in the low level easterlies to the east of the region of maximum ascent produces a deep but narrow plume of equatorial ascent that moistens the midtroposphere while weakly diffluent flow above the bl spreads moisture away from the equator vertical advection of moisture from this plume of ascent accounts for the eastward propagation of the positive moisture anomalies across the maritime continent into the western pacific when the convection is first developing over the indian ocean ho

characterization of transpressive deformation in shear zones of the archean north caribou greenstone belt nw superior province and the relationship with regional metamorphism abstract the 2 7 3 0 ga north caribou greenstone belt ncgb host to the musselwhite bif hosted gold deposit possesses abundant shear zones on its northern margins which appear to have formed under amphibolite facies conditions protracted deformation and regional metamorphism are coeval with widespread magmatism and accretion events during crustal amalgamation of the western superior province and are responsible for folding the ore hosting bif and channeling fluids the importance of shear zones in behaving as conduits for fluids during the tectonic evolution of the ncgb is not well known and their relationship with metamorphism is equivocal yet higher grade syn to post tectonic metamorphic minerals seem to correlate with loci of higher strain structural analyses support oblique transpressive collision that produced steeply dipping planar and shallowly plunging linear fabrics with dominant dextral kinematics that trend broadly parallel to the doubly arcuate shape of the belt electron backscatter diffraction analyses were conducted on strategic samples across one shear zone in order to characterize crustal conditions during transpressive deformation the dinnick lake shear zone cuts through mafic metavolcanics and at its core is an l tectonite granite composed of recrystallized quartz whole rock geochemistry shows little variation in ca na mg and k often used as indicators of hydrothermal alteration from surrounding less deformed units suggesting deformation in a dry environment microstructural analysis indicates subgrain rotation recrystallization and deformation by prism a and c slip in quartz as well as aligned hornblende that suggest deformation temperatures above 500 c quartz in mafic rocks along the margins of the shear zone also exhibits a basal a slip component indicating a slight decrease in strain or temperature although the ncgb exhibits some first order evidence of vertical tectonism dome and keel geometries the dominant strain record within shear zones is that of horizontal oblique transpressive displacement this is in agreement with other greenstone belts in the western superior province where vertical tectonism and horizontal tectonism were coeval