hafnium isotopes in zircon a tracer of fluid rock interaction during magnetite apatite kiruna type mineralization abstract in situ analyses of hafnium isotopes in zircon combined with u pb zircon ages and trace element data provide new information on the characterization and evolution of magnetite apatite kiruna type deposits and the tectonic environments in which they occur the lyon mountain granite in the adirondack mountains of new york is the host to numerous zircon bearing magnetite apatite deposits hafnium isotopic compositions and rare earth element contents in individual zircon crystals were measured in situ in both the host granites and the ore bodies by laser ablation inductively coupled plasma mass spectrometry hafnium isotopic compositions in the ore zircon can be divided into two groups those that have initial ehf t values that are indistinguishable from those of the host granites e g ehf t less than 7 and are typical of relatively juvenile proterozoic crust and those that have extremely radiogenic ehf t values as high 40 two models are proposed to explain the observed ehf t values in the zircon crystals 1 early formed ore bodies containing magnetite apatite and clinopyroxene were remobilized by secondary fluid alteration releasing zr and hf for the crystallization of new zircon or alternatively 2 fluids responsible for ore formation have interacted with garnet bearing rocks during retrograde metamorphism scavenging rare earth elements and radiogenic hf previous work done to determine the u pb ages from the same zircon crystals which were analyzed for the hf isotopic composition in this study revealed that ore bodies record a mineralizing event that is 20 to 60 m y younger than the age of granite emplacement this age discrepancy plus the highly radiogenic ehf t values in the ore zircon crystals suggests that the fluids responsible for this younger event could not have been derived from the granite hosts these data argue that magnetite apatite deposits in the lmg have multiple mineralizing events superimposed upon one another and that early formed deposits may be reworked modified and redeposited by fluids subsequent to magma crystallization

microprobe monazite geochronology understanding geologic processes by integrating composition and chronology abstractmonazite is a light rare earth element lree bearing phosphate mineral that is present in a wide variety of rock types has an extremely variable composition reflecting host rock conditions and is a robust geochronometer that can preserve crystallization ages through a long history of geological events monazite crystals typically contain distinct compositional domains that represent successive generations of monazite which in turn can provide a detailed record of the geologic history of its host rocks the electron microprobe can be used to characterize the geometry of compositional domains analyze the composition of each domain and when carefully configured determine the u th total pb age for domains as small as 5 m in width these data allow the monazite to be linked with and place timing constraints on silicate processes in the host rocks current applications span a broad range of geologic processes in igneous metamorphic hydrothermal and sedimentary rocks

partial high grade alteration of monazite using alkali bearing fluids experiment and nature recent advances in the dating of monazite using the electron microprobe indicate that thsio 4 and or cath po 4 2 enriched intergrowths in monazite can give ages younger than the original monazite the morphology of the intergrowths suggests that the original monazite grain has been partly altered by a fluid in which th si and ca are mobile this hypothesis has been tested in the piston cylinder apparatus at 1000 mpa and 900 c utilizing a natural unzoned th and pb bearing monazite ce and na 2 si 2 o 5 h 2 o during the experiment a subset of the monazite grains acquired thsi0 4 enriched areas with sharp compositional boundaries devoid of pb and show evidence of being a pseudomorphic partial replacement of the monazite rather than an overgrowth of the monazite these experiments support the hypothesis that similar th enriched or th depleted patches with sharp compositional boundaries observed in natural monazite could be the result of fluid induced alteration via coupled dissolution reprecipitation if so such altered regions would yield information concerning the nature of the fluid responsible for their formation as well as allow for the dating of single or multiple metasomatic events assuming that all pre existing radiogenic pb is removed during alteration

resetting monazite ages during fluid related alteration abstract fluid related coupled dissolution reprecipitation processes can modify the composition of monazite and other orthophosphate minerals at temperatures well below diffusional closure temperatures it is critical to evaluate the effects of alteration processes on th u pb dates especially because incomplete removal of pb during alteration could lead to spurious dates either older or younger than the actual age of the monazite formation experimental alteration of monazite at 450 mpa and 450 c has resulted in the production of altered domains in the vicinity of the grain rim as well as in the vicinity of inclusions and microfractures without any obvious structural control within grains the composition of the altered domains is relatively constant from domain to domain and from grain to grain thorium was reduced from ca 7 wt tho 2 to ca 2 wt uranium and pb were almost entirely removed from the altered domains while unaltered areas of the monazite grains as well as the original monazite grains before the experiment yield very consistent dates of ca 350 ma dates from the altered domains are consistently near zero the implication is that fluid aided alteration of monazite for the conditions of this experiment has resulted in a near complete resetting of the monazite age at temperatures well below the closure temperature because alteration textures in monazite are relatively common in nature careful analysis of such textures offers a means of recognizing and potentially dating fluid rock interactions

oxygen isotope evidence for shallow emplacement of adirondack anorthosite oxygen isotopic analysis of wollastonites from the willsboro mine adirondack mountains new york reveals a 400 ft wide zone of 18o depletion at anorthosite contacts values of 18o vary more sharply with distance and are lower to 1 3 than any yet reported for a granulite fades terrain exchange with circulating hot meteoric water best explains these results and implies that the anorthosite was emplaced at relatively shallow depths 10 km in marked contrast to the depth of granulite fades metamorphism 23 km these 18o depletions offer the first strong evidence for shallow emplacement of anorthosite within the grenville province and suggest that regional metamorphism was a later and tectonically distinct event

surface dynamic of a protalus lobe in the temperate high mountain western maladeta pyrenees abstract the maladeta protalus lobe is located in the maladetas massif central pyrenees a detailed geomorphologic map rtk gps techniques bottom temperature of the winter snowcover bts technique and datalogger to monitor the ground thermal regime were used to reveal the present day activity of the protalus lobe and its location in a mountain permafrost environment systematic monitoring using differential gps at eight fixed points throughout the surface of the protalus lobe shows vertical and horizontal displacements during the field surveys of 2008 2009 2010 2011 2012 and 2013 the recorded dynamic defines a periglacial landform with low activity and rapid interannual variations in a thermal imbalance state the location of protalus lobe in marginal periglacial environments of the temperate high mountain makes it an effective morphoclimatic geoindicator

thermobarometric modelling of zircon and monazite growth in melt bearing systems examples using model metapelitic and metapsammitic granulites u pb age data collected from zircon and monazite are used to draw fundamental inferences about tectonic processes in the earth despite the emphasis placed on zircon and monazite ages the understanding of how to relate the timing of growth of zircon and monazite to an evolving rock system remains in its infancy in addition few studies have presented large datasets of geochronological data from zircon and monazite occurring in the same metamorphic rock sample such information is crucial for understanding the growth of zircon relative to monazite in a systematic and predictive manner as per this study the data that exist support the generally held conception that zircon ages tend to be older than monazite ages within the same rock here experimental data for zircon and monazite saturation in melt bearing rocks are integrated with phase diagram calculations the calculations constrain the dissolution and growth behaviour of zircon and monazite with respect to evolving pressure temperature and silicate mineral assemblages in high grade melt bearing metasedimentary rocks several key results emerge from this modelling first that in aluminous metapelitic rocks i e garnet cordierite sillimanite assemblages zircon ages are older than monazite ages in the same rock second that the growth rate of accessory minerals is nonlinear and much higher at and near saturation than at lower temperatures and third that the difference in zircon and monazite ages from the same rock may be ascribed to differences in the temperature s at which zircon and monazite grow rather than differences in closure temperature systematics using our methodology the cooling rate of granulites from the reynolds range central australia have been constrained at 4 c myr 1 this study serves as a first pass template on which further research in applying the technique to a field study can be based

constraining the timing and character of crustal melting in the adirondack mountains using multi scale compositional mapping and in situ monazite geochronology

in situ trace element analysis of monazite and other fine grained accessory minerals by epma abstract trace element analysis of high z accessory phases by electron probe micro analysis offers unique access to data unattainable by other analytical techniques but also presents great challenges the intimate relationships between beam conditions voltage current spatial resolution precision and spectral complexity require the careful examination of all analytical parameters and their consequences at a level commensurate with the sensitivity of the desired analysis the high ree and actinide content and resulting high z of monazite allows high direct analytical resolution below 500 nm at 10 kv depending on the realized beam diameter due to limited electron range but the high concentration of these elements will also produce significant fluorescence at a distance the use of high accelerating potential in an effort to improve counting statistics is injudicious in most cases as direct analytical resolution decreases and high overvoltage on rees and th in monazite results in efficient production of energetic ionizing radiation l series capable of fluorescing elements of interest or interfering elements at remarkable distances at least several 10 s of microns from the beam boundary fluorescence is a very significant problem in trace element analysis and in geochronologic analysis of monazite as grains are commonly complex with micro domains that differ considerably in composition especially th ree in such instances a 15 kv beam can produce fluorescence at a distance leading to errors of 10 s of ppm within 5 m of a compositional boundary for trace element analysis effects such as background curvature and minor interferences can result in very large errors 50 or more for curvature alone for concentrations at or below 100 ppm strong background curvature is observed for all makes and varieties of spectrometers in the pb m region in addition for ree and actinide bearing phases such as monazite the wavelength regions available for background determination are very limited requiring routine high precision scanning and regression modeling to determine reasonably accurate background intensities two point background interpolation methods are inappropriate for high sensitivity analysis in all cases without a direct means to verify the accuracy of low concentration analyses great attention must be paid to analytical protocol and very detailed spectral analysis the use of consistency standards to monitor changes is important but caution must be exercised in the use of secondary age standards in the case of monazite epma because systematic error can result in cancellation effects when concentrations of both parent and daughter are proportionally incorrect in all cases caution in interpretation and integration of all available information is necessary if the potential of the method is to be realized

format and philosophy for collecting compiling and reporting microprobe monazite ages microprobe monazite dating has been increasingly used to constrain the timing of deformation and metamorphism because of the potential to date very small monazite domains down to 5 m or less in structural and petrologic context this paper presents an analytical strategy presentation format and error considerations for microprobe monazite dating the strategy involves high resolution compositional mapping to delineate compositional domains within monazite crystals then for each compositional domain a series of th u and pb analyses are made and a single date and error are calculated the number of analyses in each domain is determined by the desired statistical precision of the date results from several monazite grains are typically combined and along with textural relationships are used to build an argument that the dates constrain the age of a deformation or metamorphic event the total error involves three components short term random error dominated by counting statistical uncertainty short term systematic error uncertainty in background correction conductive coating variation and calibration and long term systematic error uncertainty in standard composition mass absorption factors decay constants etc in homogeneous compositional domains short term random errors 2 of less than 10 m y can be obtained from five to ten analyses however short term systematic error mainly background estimation uncertainty would typically result in a doubling of the magnitude of random error microprobe dates are presented as a single gaussian probability distribution for each domain along with representative compositional maps it is recommended that a consistency standard be analyzed during each analytical session and the results be reported along with those from the unknown this proposed strategy and format are compatible with those of other geochronological techniques they incorporate analytical limitations associated with trace as opposed to major element microprobe analysis and will allow better comparisons to be made between labs and between different geochronological techniques

electron microprobe dating of monazite because monazite is extremely rich in u and th radiogenic pb pb accumulates very quickly and reaches in about 100 ma a level where it is possible to analyse it with the electron probe assuming that common pb is negligible and that partial loss of pb has not occurred the simultaneous measurement of u th and pb allows to obtain a geologically meaningful age from a single electron probe analysis here we present the results of two years of systematical investigations aiming to define both the limits and potential of this method a specific statistical method to deal with the large number of data which can be obtained on a single sample is described and several guidelines illustrated by examples are suggested to optimize the method electron probe measurements carried out on samples of known age from 200 ma to 3 1 ga yield ages that always fall inside the confidence interval of the isotopically determined age demonstrating that this method is reliable the younger age limit is approximately 100 ma although it can be younger in some favourable cases in old monazites extremely high pb contents have been found up to 5 wt indicating that monazite can tolerate high radiation doses without experiencing lead loss the final precision on the age for a normal monazite is 30 50 ma for a total counting time of 600 s a complete dating procedure can be completed in less than 1 h first results indicate that old ages can be preserved in monazite either in small relict cores in crystals or by the coexistence of several generations of monazites in a sample this method has all the advantages of the electron probe it is non destructive has an excellent spatial resolution monazites as small as 5 i m can be dated and because it is possible to work on normal polished thin sections the petrographical position of the dated crystal is known this method offers a large number of geologists access to an in situ dating technique at moderate cost

granite emplacement during tectonic exhumation the adirondack example sensitive high resolution ion microprobe u pb zircon ages for late to posttectonic leucogranites fix the timing of extensional collapse of a portion of the mesoproterozoic grenville orogen of eastern north america plutons of lyon mountain granite lmg were emplaced within the carthage colton shear zone synchronously with formation of extensional mylonite at 1045 1037 ma leucogranite melts were generated in the hot granulite facies core of the adirondack highlands central granulite terrane that served as the lower plate for down to the northwest extension the lmg suite is associated with hightemperature hydrothermal magnetite deposits in the adirondack highlands and widespread cl 1 co2 hydrothermal alteration of upper plate rocks is localized along the carthage colton shear zone where lmg granites are present the relationships between melt generation granite intrusion high strain rates extensional collapse and hightemperature hydrothermal activity provide a framework for understanding midcrustal processes in modern and ancient orogenic belts

on the pseudomorphing of melt filled pores during the crystallization of migmatites pseudomorphs of melt filled pores recognized by their generally cuspate shape are used as diagnostic for the former presence of partial melt they are commonly observed in migmatites from the mid to deep crust although they occur in the smaller pores in migmatites from shallower levels 1 2 kbar the pseudomorphing of meltfilled pores is controlled by the kinetics of nucleation and is a consequence of the greater supersaturation required for nucleation in a small pore compared with a larger one we examine three migmatites in detail a contact metamorphosed cherty band from an iron formation an archaean regional granulite from an accretionary prism and an amphibolite facies sample from the roots of an archaean mountain chain the greater undercooling required for nucleation in progressively smaller pores is recorded by the composition of plagioclase pseudomorphs a study of dihedral angles at the corners of pseudomorphed pores demonstrates that melt solid textural equilibrium was probably attained only in the contact aureole the regional granulite preserves an almost unmodified reaction controlled melt distribution with little evidence for either melt solid textural equilibration or solid solid re equilibration whereas the reactioncontrolled melt distribution in the regional amphibolite facies example has been modified by a partial approach to solid solid textural equilibrium it is not clear whether the differences in dihedral angle population are due to differences in uplift and exhumation rates or due to the presence of h2o on grain boundaries

exploring laser ablation u pb dating of regional metamorphic garnet the straits schist connecticut usa abstract garnet is a prominent recorder of metamorphic processes and plays a pivotal role in deciphering the pressure temperature evolution of metamorphic rocks however the potential of regional metamorphic garnet for laser ablation u pb dating remains unexplored as variable and low u we applied la icp ms u pb dating to garnet and zircon monazite and xenotime from the straits schist western connecticut usa to constrain the timing of garnet growth within the overall acadian age metamorphic history recorded by this unit we assessed the effects of u rich inclusions on garnet u pb data using high resolution microbeam sampling grain size analysis and calculations assessing how inclusion size and abundance affect u concentrations measured in garnet when analysing garnet our results demonstrate that by scrutinizing the time resolved u signal u rich inclusions can be identified and effectively removed during data evaluation if u rich inclusions are unaccounted for garnet analyses have elevated u contents compared to pure garnet and in a tera wasserburg diagram data points are shifted to the left right or along the garnet regression line for inclusions older younger or of the same age as the garnet respectively garnet from two metapelitic samples yielded lower intercept ages of 409 10 ma and 406 15 ma and a combined u pb age of 406 1 8 3 ma metamorphic zircon yielded age clusters at 446 2 4 2 ma 413 3 3 0 ma and 382 9 2 8 ma monazite ages range between 390 and 355 ma and xenotime yielded 370 1 5 6 ma the 446 ma age peak is attributed to detrital zircon formed during the waning stages of the taconian orogeny early acadian metamorphism is recorded by garnet and 413 ma zircon whereas monazite and zircon ages of 390 to 383 ma coincide with peak metamorphic conditions early carboniferous monazite and xenotime ages could reflect the incursion of fluids into the straits schist during neo acadian metamorphism coeval plutonism in new england or breakdown of garnet during regional exhumation

behaviour of apatite during partial melting of metapelites and consequences for prograde suprasolidus monazite growth abstract the suprasolidus behaviour of apatite and monazite is examined for an average metapelite composition using phase equilibria modelling coupled with solubility equations of these minerals both closed and open system scenarios are considered partial melting above the solidus requires apatite and monazite breakdown in order to saturate the anatectic melt in phosphorus and the light rare earth elements in general melt loss is predicted to increase the stability of apatite and monazite at high temperature most apatite is predicted to survive up to ultrahigh temperature conditions except for rocks with low bulk phosphorus concentrations by contrast most monazite is expected to be consumed by uht conditions thorium substitution in monazite is expected to increase the stability of monazite to higher temperatures the presence of lree rich apatite decreases the stability of monazite above the solidus but the breakdown of this apatite during anatexis may generate prograde monazite at the apatite melt interface in local pockets of melt oversaturation however prograde suprasolidus monazite along grain boundaries is expected to be consumed during further partial melting or during melt homogenization when an interconnected melt network develops anatectic melts are predicted to be saturated with respect to apatite except at uht conditions and for rocks with low initial p2o5 bulk concentrations

geochronology and magmatic evolution of the dieng volcanic complex central java indonesia and their relationships to geothermal resources abstract we analyzed new radiometric dating and petrological data of dvc in an attempt to reconstruct volcanic history as groundwork to understand magmatic temporal and spatial evolution the magma of dvc can be divided on the basis of mineral composition into three types olivine bearing basalt basaltic andesite pyroxene basaltic andesite andesite and biotite andesite dacite which coincide with three volcanic episodes of dvc pre caldera second and youngest episode respectively the pre caldera episode was active no later than 1 ma the second episode occurred between 0 3 and 0 4 ma and the youngest occurred after 0 27 ma plots of cao k2o al2o3 and rb sr against feo mgo and or mgo suggest that each volcanic episode has distinct differentiation trends indicating the presence of multiple shallow magma chambers the close spatial relationship between the geothermal manifestation geophysical anomalies geothermal production zones and volcanic edifices supports the presence of multiple shallow magma chambers beneath dvc which act as a heat source for the existing geothermal system

shrimp u pb zircon geochronology of the anorthosite mangerite charnockite granite suite adirondack mountains new york ages of emplacement and metamorphism

timing of anatexis in the eastern adirondack highlands implications for tectonic evolution during ca 1050 ma ottawan orogenesis u pb sensitive high resolution ion microprobe shrimp analyses of zircons from migmatitic metapelites in the eastern adirondack highlands demonstrate that substantial anatexis took place ca 1050 ma during the late but still high grade ca 1090 1050 ma ottawan orogeny these results contrast with data from metapelites of the southwestern adirondack highlands and adirondack lowlands which indicate that anatexis occurred ca 1200 1160 ma during the shawinigan orogeny and subsequent ca 1155 ma anorthosite mangerite charnockite granite amcg magmatism ca 1180 1150 ma zircons from this western regime do not contain ca 1050 ma ottawan metamorphic overgrowths the absence of ca 1050 ma ottawan anatexis and overgrowths in the adirondack lowlands is explained by the observation that consistent with titanite cooling ages post 1150 ma temperatures did not exceed 700 c in the southwestern adirondack highlands the absence of ca 1050 ma anatexis can be accounted for by earlier dehydration of metapelites during ca 1180 1150 ma shawinigan amcg metamorphism the occurrence of ca 1050 ma anatexis and formation of metamorphic zircons in the eastern adirondacks cannot be explained by higher temperatures because geothermometry indicates that all of the adirondack highlands reached a nearly uniform 750 800 c during this period accordingly the occurrence of ca 1050 ma ottawan anatexis in the eastern regime is interpreted to be the result of 1 infl uxes of hydrous fl uids at ca 1050 ma or 2 decompression melting during late extensional exhumation a recently recognized low angle late ottawan ca 1050 ma fault system may have provided both fl uid conduits and footwall decompression the sense of displacement along the shear zone has not yet been unequivocally determined but preliminary investigations of kinematic indicators demonstrate normal displacement thus this structure may be an analogue of the ca 1050 ma northwest dipping carthage colton zone normal fault system that juxtaposed the adirondack lowlands against the adirondack highlands in this context these fault zones form a quasi symmetrical core complex or gneiss dome within which the high grade core of the adirondack highlands was tectonically exhumed a similar east dipping along strike normal fault in quebec tawachiche shear zone exhumed the eastern morin and lac taureau terranes at ca 1050 ma and may merge with the eastern adirondack shear zone described here

permafrost conditions in the mediterranean region since the last glaciation the relatively warm climate conditions prevailing today in the mediterranean region limit cold geomorphological processes only to the highest mountain environments however climate variability during the late pleistocene and holocene has led to significant spatio temporal variations of the glacial and periglacial domain in these mountains including permafrost conditions here we examine the distribution and evolution of permafrost in the mediterranean region considering five time periods last glaciation deglaciation holocene little ice age lia and present day the distribution of inactive permafrost derived features as well as sedimentary records indicates that the elevation limit of permafrost during the last glaciation was between 1000 m and even 2000 m lower than present permafrost was also widespread in non glaciated slopes above the snowline forming rock glaciers and block streams as well as meter sized stone circles in relatively flat summit areas as in most of the northern hemisphere the onset of deglaciation in the mediterranean region started around 19 20 ka the ice free terrain left by retreating glaciers was subject to paraglacial activity and intense periglacial processes under permafrost conditions many rock glaciers protalus lobes and block streams formed in these recently deglaciated environments though most of them became gradually inactive as temperatures kept rising especially those at lower altitudes following the younger dryas glacial advance the early holocene saw the last massive deglaciation in mediterranean mountains accompanied by a progressive shift of permafrost conditions to higher elevations it is unlikely that air temperatures recorded in mediterranean mountains during the holocene favoured the existence of widespread permafrost regimes with the only exception of the highest massifs exceeding 2500 3000 m lia colder climate promoted a minor glacial advance and the spatial expansion of permafrost with the development of new protalus lobes and rock glaciers in the highest massifs finally post lia warming has led to glacial retreat disappearance enhanced paraglacial activity shift of periglacial processes to higher elevations degradation of alpine permafrost along with geoecological changes

rock glaciers and the geomorphological evolution of deglacierizing mountains abstract rock glaciers are an important geomorphic element of glaciated mountain landscapes but our understanding of their distribution and ages controls on their development and their importance in regional mountain hydrology and mountain geomorphic evolution is incomplete in part this incomplete knowledge arises through problems associated with identifying rock glaciers on a morphological basis alone amplified by the multiple ways in which rock glaciers can form in different glacial periglacial and paraglacial settings this study focuses on rock glaciers as a paraglacial mountain landscape element and considers the relationships between rock glaciers and glacial periglacial and paraglacial processes new geomorphic and sedimentary data on different rock glaciers from the khumbu region of nepal are presented these data show that even within a single region rock glaciers may have varied origins and thus likely ages and different climatic and environmental controls we argue that rock glaciers in deglacierizing mountains may have a long residence time in the landscape unlike many other glacially influenced mountain landforms and can undergo significant morphodynamic changes as glaciated landscapes transition into paraglacial landscapes

melt enhanced deformation a major tectonic process convergent tectonics between continental crustal blocks result in deep burial and anatexis of supracrustal rocks anatectic and or mantle derived melts combine to form a melt weakened zone in the thickened lower crust the accumulation of melt eventually leads to crustal failure along melt lubricated shear zones rapid 1 mm yr vertical component movements of large crustal blocks result we refer to these crustal displacements as tectonic surges the melt lubricated shears are characterized by the close association of sheared country rocks with foliated or massive igneous sills and plutons rocks that formed at different crustal levels are juxtaposed across these shear zones one result of surges with large lateral component of movement is metamorphic inversion with high pressure and high temperature metamorphic rocks structurally over lower pressure and temperature assemblages large and rapid vertical surges may displace crust containing abundant melt and may result in high t p including granulite facies metamorphism and preservation of metamorphic textures caused by rapid decompression

direct dating of adirondack massif anorthosite by u pb shrimp analysis of igneous zircon implications for amcg complexes the low abundance of igneous zircon in proterozoic massif anorthosites has presented a major obstacle to the acquisition of direct absolute ages of crystallization for these important rocks indirect dating that relies on zircon ages from associated mangerite charnockite granite granitoids assumes that they have a coeval relationship with anorthosite that requires documentation shrimp sensitive high resolution ion microprobe u pb zircon dating techniques provide a powerful means for directly dating the small populations of zircons in anorthositic rocks and for resolving problems with inheritance within the adirondack mountains 10 samples of massif anorthosite have yielded more than sufficient quantities of igneous zircon to establish directly the ages of the region9s classic anorthosite occurrences e g the marcy and oregon dome massifs in addition a ferrogabbro a ferrodiorite and a coronitic olivine metagabbro all crosscutting massif anorthosite were dated the average age of this suite of 13 anorthositic samples is 1154 6 ma mswd mean square of weighted deviates 0 26 probability 0 99 in addition eight associated granitoids have been dated by shrimp techniques and complement another five previously dated by multi grain thermal ionization mass spectrometry tims methods the 13 granitoids yield an average age of 1158 5 mswd 0 89 probability 0 60 and are broadly coeval with the massif anorthosite the overlapping ages provide evidence that these rocks constitute a single composite anorthosite mangerite charnockite granite amcg suite intruded at ca 1155 ma an age corresponding to the ages of major amcg suites in the grenville province in canada e g morin and lac st jean although rocks of the adirondack amcg suite are now documented as broadly coeval it does not follow that the constituent amcg lithologies were comagmatic field relationships and mineral disequilibria in transitional zones are inconsistent with derivation from a single parental magma moreover the presence of older ca 1 2 1 3 ga inherited cores in some zircons from amcg granitoids conflicts with derivation of these rocks from magmas that formed anorthosite gabbro or ferrodiorite or jotunite in which zircons are highly soluble the slightly older ca 1158 ma average age of the mangeritic and charnockitic members of the amcg suite is consistent with an origin as early lower crustal anatectites that left behind pyroxene plagioclase restites this refractory material then reacted by assimilation fractional crystallization afc with ponded mantle derived gabbroic magmas to produce plagioclase rich crystal mushes with crustal isotopic signatures as proposed much earlier by r f emslie these magmas are considered to be parental to the adirondack anorthosite and upon ascent they were emplaced in proximity to still hot earlier mangeritic and charnockitic bodies where they underwent further fractionation the composite nature of the marcy massif documents that this process was repeated in several sequential pulses

fabric shape and the interpretation of sedimentary fabric data abstract the concept of fabric shape provides a powerful means of visualizing and analyzing data on sedimentary fabric the shape of a fabric is defined in terms of the ratios between eigenvalues s1 s2 and s3 derived using the orientation tensor method a continuum of all possible orthorhombic fabric shapes can be clearly represented on equilateral ternary diagrams originally developed for the presentation of particle shape data two indices are of particular value in scaling these diagrams fabric isotropy i s3 s1 and fabric elongation e 1 s2 s1 together these indices uniquely define the shape of any orthorhombic fabric and provide a rational and quantitative basis for reconstructing depositional and de ormational processes equilateral ternary diagrams provide a more versatile and powerful basis for analyzing fabric data than other eigenvalue diagrams now in use use of the diagrams in reconstructing processes of sediment transport and deposition is illustrated using fabric data from subglacial tills and a variety of slope deposits

pb diffusion in monazite a combined rbs sims study abstract we report measurements of pb diffusion in both synthetic cepo4 and natural monazites run under dry 1 atm conditions powdered mixtures of prereacted cepo4 and pbzro3 were used as the source of pb diffusant for in diffusion experiments conducted in sealed pt capsules for durations ranging from a few hours to several weeks following the diffusion anneals pb concentration profiles were measured with rutherford backscattering spectroscopy rbs and supplemented by measurements with secondary ion mass spectrometry sims in order to evaluate potential compositional effects upon pb diffusivity and simulate diffusional pb loss that might occur in natural systems we also conducted out diffusion experiments on pb bearing natural monazites in these experiments monazite grains were surrounded by a synthetic zircon powder to act as a sink monazites from these experiments were analyzed with sims over the temperature range 1100 to 1350 c the arrhenius relation determined for in diffusion experiments on synthetic monazite is given by d 0 94 exp 592 39 kj mol 1 rt m 2 s 1 diffusivities for synthetic and natural monazites are similar as are results of measurements made on the same samples using both rbs and sims the activation energy for pb diffusion we determined is more than three times that for natural monazite reported previously with pb diffusivities at

little ice age glaciation and current glaciers in the iberian peninsula little ice age lia glacier advance has been registered in three of the main iberian high mountain areas pyrenees picos de europa and sierra nevada during the lia three different glacial env

lyon mountain ferroan leucogranite suite magmatic response to extensional thinning of overthickened crust in the core of the grenville orogen

rock glacier dynamics in marginal periglacial environments vertical electric sounding bottom temperature of winter snowcover bts and ground thermal measurement debris surface analysis and a differential global positioning system dgps survey were performed on the posets rock glacier pyrenees between 2001 and 2008 high precision records of horizontal and vertical movements of the rock glacier were measured using a dgps on ten steel rods total and annual average displacements and thickness changes for each control point were derived from the field survey horizontal and vertical displacement rates in different sectors of the rock glacier were compared and these compared with thermal structural and morphological maps the inferred surface deformation was characterized by extensional and compressive flows in which two dynamic types were found the first type of movement is defined by the slide and flows related to the existence of an ice body over the frost body the second dynamic type involved the displacement generated by deformation of the frozen body the study attempts to understand the surface movement and dynamics of rock glaciers in marginal cold environments and their usefulness as environmental geoindicators copyright 2010 john wiley sons ltd

mineral zoning p t x m phase relations and metamorphic evolution of some adirondack granulites new york detailed petrologic analysis of ten meta anorthosites and related introduction rocks from the adirondack highlands new york has been used to the adirondack highlands of new york are one of constrain the p t history of the region metamorphic orthopyroxene the best studied granulite facies terranes of the world and clinopyroxene occur in aggregates of 1 mm diameter grains e g bohlen et al 1985 valley et al 1990 and that are zoned concentrically with decreasing al and fe fe mg references therein based on this considerable volume and increasing ca towards the rim moreover zoning is not related of work the peak metamorphic conditions in the to the presence of garnet zoning is interpreted to have been produced adirondack highlands have been fairly well constrained during growth by the reaction igneous pyroxene plagioclase at pressures of 7 8 kbar crustal depths of 25 30 metamorphic opx metamorphic cpx along a cooling path with a km and temperatures that range from 775 c in slope of 6 bars c starting at 850 c and 6 5 8 kbar garnet the central highlands to t 675 c in the southern occurs as isolated clusters of 5 25 grains of 1 mm diameter adirondacks e g bohlen et al 1985 p t paths have crystals and as necklaces of 1 mm diameter crystals surrounding been shown to follow nearly isobaric cooling trajectories metamorphic pyroxenes or oxides plagioclase quartz typically e g bohlen 1987 because of this wealth of inseparates garnet from pyroxene but locally garnet embays metaformation some fundamental questions about the origin morphic pyroxene suggesting that garnet grew at the expense of of the adirondack granulite facies terrane have emerged pyroxene garnet clusters have slightly lower fe fe mg than e g bohlen et al 1985 how did the crust achieve garnet in necklaces fe fe mg 0 73 and 0 75 0 78 rethe relatively high temperature conditions necessary to spectively and slightly higher grossular xgrs 0 20 vs 0 19 produce granulite facies rocks at depths of 25 30 km neither is zoned in mn and zoning towards increasing fe and what is the relative importance of magmatic fe mg is restricted to contacts with biotite and locally clinoheating vs continental burial in this process pyroxene biotite adjacent to garnet is zoned towards decreasing this study will present new data on mineral comfe fe mg production of garnet in necklaces is interpreted position and element zoning in garnet pyroxene to be the result of the continuous fe mg reaction opx pl biotite amphibole and plagioclase from adirondack grt cpx qtz p t x m modeling of this reaction reveals a meta anorthosite and related rocks with the goal of p t path with a slope of 6 bars c no evidence for early prefurther constraining the metamorphic evolution of this metamorphic peak garnet is observed which rules out any possibility terrane mineral compositions will be used to construct of early higher pressure metamorphism the p t path is therefore phase diagrams in an attempt to evaluate approach to inferred to be counterclockwise with loading to 6 5 8 kbar at a chemical equilibrium theoretical analysis will be used maximum temperature of 850 c occurring during or immediately to construct p t x m phase diagrams depicting how following an influx of heat presumably from early orogenic plutons mineral composition and modes change with p and t this theoretical analysis will then be applied to the mineral zoning to constrain the p t path and the results will be discussed in the context of a tectonic

current transition from glacial to periglacial processes in the dolomites south eastern alps abstract a close relationship between glacial and periglacial landforms is frequently observed in alpine environments where a transition from glacial to periglacial processes often took place after the end of the little ice age lia understanding the origin of these landforms is challenging and assessing the current spatial domain of glacial and periglacial processes may be a difficult task in high relief areas where thick and widespread debris cover often characterize rapidly decaying glaciers here we present a comprehensive study of a composite landform located in the dolomites south eastern alps combining geomorphological geophysical and topographic surveys with ground surface temperature measurements results indicate that a debris covered glacier persists in the upper part rather large compared to the lia extent but currently inactive and rapidly losing mass an active rock glacier exists in the lower part surrounded by discontinuous permafrost a frozen body about 10 m thick was detected in the rock glacier and geomorphological evidence suggests that this ice mass is completely detached from the debris covered glacier our findings suggest that the lower part of the composite landform is probably a remnant of the ancient glacier tongue and is currently evolving under periglacial conditions periglacial processes are therefore replacing glacial processes which dominated in this site during the lia

fluid mediated partial alteration in monazite the role of coupled dissolution reprecipitation in element redistribution and mass transfer monazite ce lree th u ca p si o4 with complex zoning in th and other elements is commonly observed in metamorphic and igneous rocks the hypothesis that this alteration is a product of fluid mediated element mass transfer has been tested in the piston cylinder press caf2 assembly cylindrical graphite oven at 1 000 mpa and 900 c and in cold seal autoclaves on a hydrothermal line at 500 mpa and 600 c experiments included a relatively homogeneous monazite ce 7 8 wt tho2 from a heavy mineral sand plus a series of alkali bearing fluids including 2n naoh 2n koh and na2si2o5 h2o experiments were conducted using bse imaging emp analysis and both tem and hrtem a subset of monazite grains from each experiment show evidence of partial alteration in the form of areas enriched in th si with sharp curvilinear compositional boundaries extending from the grain rim into the monazite interior these thsio4 enriched textures are similar to those commonly seen in natural examples of metasomatised monazite in both magmatic and metamorphic rocks in the na2si2o5 h2o experiments scarce inclusions of britholite formed in the altered monazite the altered monazite is also characterised by strong depletion in pb ca and y thorium and si mobility coupled with the formation of britholite inclusions during partial alteration in the monazite grain is considered to be the product of fluid aided coupled dissolution reprecipitation as opposed to solid state diffusion since other fluids including nacl and kcl brines do not result in the formation of these textures the experimental replication of thsio4 enriched areas in the monazite strongly suggests that similar textures in monazite observed in nature are fluid induced specifically by alkali bearing fluids if true complex metasomatically induced textures in monazite could yield information concerning the nature of the fluid responsible for their formation as well as allow for the dating of the metasomatic event presuming that all the original radiogenic pb has been removed

spatial distribution and morphometry of permafrost related landforms in the central pyrenees and associated paleoclimatic implications abstract present and past permafrost distribution in the pyrenees is still under discussion as in other mid latitude mountain regions rock glaciers and protalus lobes are the main indicators of permafrost conditions in this paper we examine the distribution of these landforms in aran and boi valleys formerly glaciated u shaped valleys ranging from 600 to 3000 m in the southern and northern sides of the central pyrenees respectively the spatial distribution of these landforms and their chronostratigraphic position within the valley allow a better understanding of the climatic and environmental conditions necessary for their development up to 151 permafrost related landforms were identified in the boi valley including 56 rock glaciers and 95 protalus lobes in the case of the northern aran valley 76 rock glaciers and 89 protalus lobes were cataloged corresponding to 165 landforms most of the landforms 93 for rock glaciers and 95 for protalus lobes are located inside the glacial cirques with a few distributed in the slopes of the formerly glaciated valleys the lowest elevation of rock glaciers is situated at 1744 m aran and 2007 m boi whereas the lowest protalus lobes are located at 1740 m and 2033 m respectively therefore this altitude may be indicative of the lowest level recording permafrost conditions during the period in which these landforms formed with paleotemperatures ca 7 8 c lower than present day between 60 and 70 of the protalus lobes and rock glaciers are located between 2300 and 2600 m in boi valley and 2100 and 2400 m in aran valley the aspect shows a prevailing orientation of nw n and ne for both cases of rock glaciers and protalus lobes being almost absent in the s se and sw aspects the average slope of both landforms lies between 11 and 27 with a maximum of 35 for rock glaciers and 29 for protalus lobes the amplitude length ratio reveals that rock glaciers placed at lower altitudes are more elongated the chronostratigraphic position of these landforms within the valley and with respect to the moraine complexes suggests the existence of three generations of permafrost related landforms which are associated to the massive deglaciation process between the maximum glacial advance of the last glaciation and the holocene

40ar 39ar geochronology of santo antao cape verde islands santo antao the northernmost island of the cape verde archipelago consists entirely of silica undersaturated volcanic products and minor intrusions 40ar 39ar incremental heating experiments have been carried out on 24 samples that cover the entire exposed chronological sequence the oldest lavas 7 57 0 56 ma representing an older volcanic basement are exposed about 620 m above mean sea level after an interval of quiescence of up to 4 3 ma the volcanic activity resumed and continued at low eruption rates the older basement is unconformably overlain by a ca 810 m thick lava sequence that spans an age range from 2 93 0 03 to 1 18 0 01 ma this sequence is cut by many dykes and sills simultaneous volcanic activity occurred in the northeastern central and eastern part of the island a phonolitic pumice deposit that forms a noteworthy feature over most of the island has an estimated age of 0 20 ma this predates volcanic activity that formed the highest point of the island tope de coroa which has an age of 0 17 0 02 ma the most recent eruption on the island formed nephelinitic lavas in the porto novo region at 0 09 0 03 ma the oldest volcanism exposed on santo antao which took place about 7 6 ma ago was simultaneous with waning activity on maio at the eastern end of the cape verde archipelago

rock glacier dynamics and paleoclimatic implications many rock glaciers contain massive ice that may be useful in paleoclimate studies interpreting geochemical ice core records from rock glaciers requires a thorough understanding of rock glacier structure and dynamics high precision surface velocity data were obtained for the galena creek rock glacier absaroka mountains wyoming surface velocities range from 0 to 1 00 m yr and vary across the rock glacier in a manner similar to true glaciers we used glen s flow law to calculate the thickness of the deforming ice layer the modeled ice thickness ranges from 0 to 50 m and is confirmed by direct observations this agreement shows that rock glacier movement can be entirely explained by deformation of massive ice within the rock glacier neither basal sliding nor deformation of basal debris is necessary recovered ice cores to depths of 25 m contain thin debris layers associated with summer ablation in the accumulation zone the ages of four samples of organic material removed from several debris layers inthe southern half of the rock glacier range from 200 40 to 2250 35 14c yr b p demonstrating that the rock glacier formed well before the little ice age and may contain ice dating to the middle holocene or earlier

a new model of rock glacier dynamics abstract rock glaciers have traditionally been described as periglacial landforms and thus associated genetically with the presence of permafrost and a seasonal active layer they have also been described as glacigenic in origin in which the main rock glacier body contains glacier ice at depth other rock glaciers can be considered as relict where they contain no interstitial ice and are functionally inactive although all rock glaciers are to some extent polygenic there is no clear simple test that can be used to distinguish between different rock glacier types this study proposes a simple and testable model for rock glacier classification based on their behaviour from evidence reported from the literature the study then proposes an interpretive evolutionary model describing the temporal evolution of rock glacier surface movement through the year that can inform on its dynamical controls this analysis provides an easily deployed interpretive framework for the origins of rock glaciers

pebbly versus bouldery rock glaciers morphology structure and processes abstract differences in rockwall geology cause two types of rock glaciers a bouldery rock glacier having the active layer composed of matrix free boulders derived from crystalline rocks and massive limestone and a pebbly rock glacier consisting of matrix supported debris derived from less resistant shale and platy limestone such material composition controls transport processes responsible for the shape size and internal structure of the two types of rock glaciers this paper compares the major processes controlling the morphology and structure of the two types in the swiss alps based on mapping description of geological and morphological characteristics direct observation of stratigraphy and geophysical soundings of internal structure in the swiss alps pebbly rock glaciers are distinguished from bouldery rock glaciers by the clast size of 15 20 cm in the mean b axis diameter the former are fed by small scale rockfalls debris flows and solifluction whereas the latter mainly originate from large rockfalls pebbly rock glaciers are generally smaller 100 k m in bouldery rock glaciers appears to originate from snow banks buried with deposits of large rockfalls from the large source rockwall

late ottawan extension in the eastern adirondack highlands evidence from structural studies and zircon and monazite geochronology syn to postorogenic collapse is increasingly being recognized as a fundamental process in most orogens although the mechanism of collapse at mid to lower crustal levels is not well understood the adirondack highlands of the grenville province in northern new york are an exhumed granulite terrane and represent an ideal setting in which to investigate mid to lower crustal orogenic processes although the highlands experienced high grade metamorphism and crustal thickening during the ottawan orogeny few extensional shear zones have been recognized in this region we document a new shear zone in the eastern adirondack highlands that accommodated postorogenic extensional collapse during the late ottawan the shear zone accommodated extension via noncoaxial top to the southeast shear although we cannot rule out a significant coaxial vertical thinning component some earlier thrust motion may also have occurred in the zone u pb sensitive high resolution ion microprobe zircon and in situ electron probe u th pb monazite ages demonstrate that extension occurred from ca 1050 to 1025 ma following peak metamorphism during the ottawan orogeny our results suggest that late ottawan extension in the adirondack highlands was more widespread than previously recognized and was likely driven by gravitational collapse extension along this eastern adirondack highlands shear zone may connect with the tawachiche shear zone to the north in quebec indicating that tectonic exhumation during the ottawan occurred on a system of interconnected shear zones top to the northeast extension in the eastern adirondack highlands was synchronous with top to the northwest extension on the carthage colton shear zone in the western adirondack highlands suggesting that the highlands granulite terrane may have been partially exhumed as a large scale symmetrical gneiss dome

timing of anatexis in metapelites from the adirondack lowlands and southern highlands a manifestation of the shawinigan orogeny and subsequent anorthosite mangerite charnockite granite magmatism anatectic leucogranites are common in metapelites within both the highlands and lowlands terranes of the adirondack mountains of northern new york state the formation of these igneous bodies which are folded in the lowlands and commonly mylonitized in the highlands has been widely considered an event accompanying the ca 1050 ma ottawan orogeny during which metamorphic grade reached granulite facies in the highlands while the lowlands experienced amphibolite facies metamorphism sensitive high resolution ion microprobe shrimp analyses of zircons separated from leucosomes and melanosomes in both the southern highlands and the lowlands indicate that primary anatexis occurred ca 1180 1160 ma and is thus a manifestation of heating during the earlier shawinigan orogeny ca 1210 1160 ma and associated anorthosite mangerite charnockite granite amcg magmatism ca 1165 1150 ma the absence of ottawan overgrowths on shawinigan zircons in these leucosomes suggests that by ottawan time the rocks were too dry for further melting or zircon growth to occur however electron microprobe analyses of monazites from the southern highlands reveal multiple age zones including cores with ages of ca 1170 1180 ma consistent with primary growth during shawinigan orogenesis complex zones formed ca 1140 1155 ma during amcg magmatism and ca 1050 1020 ma formed during ottawan orogenesis and high grade metamorphism throughout the adirondacks leucosomes and melanosomes contain older ca 1320 ma zircons that are considered to be remnant detrital zircons derived from arc rocks of the elzevirian terrane the apparent absence of archean detrital zircons suggests that the protoliths of the metapelites were deposited in restricted basins that did not receive detritus from the superior craton

glacigenic clast fabrics genetic fingerprint or wishful thinking the interpretation of glacigenic diamictons is a subjective process for which quantitative support is frequently sought from parameters such as clast shape and fabric it has been widely suggested that different glacigenic diamicton facies possess distinct clast fabric signatures this paper examines this concept using a data set of 111 clast fabrics and a synthesis of published results eigenvalues are calculated and compared for a variety sedimentary facies it is concluded that clast fabric alone is not able to discriminate between different glacigenic facies and it is argued that clast fabric offers little quantitative support in the interpretation of glacigenic sediments it is suggested therefore that although clast fabric may continue to have a role as an indicator of relative strain at specific sites its use in the discrimination of glacigenic facies is limited consequently we should be much more selective in undertaking such analyses in the future copyright 1999 john wiley sons ltd

the role of melt in the uplift and exhumation of orogenic belts abstract in some orogenic belts rapid pulses of uplift occur when melt is present detailed work on the relation of melt to structural and metamorphic features in several localities shows that hot metamorphic rocks and especially anatectic migmatite can be physically transported from the lower to middle crust on decollements the decollements form in the lower crust because even though the lower crust is structurally weak throughout due to thermally activated crystal plastic deformation mechanisms the crust is substantially weakened where melt forms or is intruded melt in the lower crust is present long enough to accomodate strain whereas in the upper crust it crystallizes too fast to be a factor in strain localization following crustal loading due to thrusting exhumation results in the formation of additional melt in the migmatites due to decompression melting support of this sequence of events includes 1 evidence for near isothermal decompression of high temperature metamorphic rocks with early high pressure minerals having formed pre or synchronous with penetrative deformation and with lower pressure minerals having formed after the deformation 2 the occurrence of magma sheets that occur along decollements between high temperature metamorphic rocks and lower temperature metamorphic rocks in either thrust or normal configurations 3 nearly concordant k ar cooling dates for biotite and hornblende suggesting rapid cooling rates and 4 post tectonic intrusions of leucogranite or leucotonalite that may represent the products of decompression melting the crystalline slabs of the high himalaya the compressional surges of the coast orogen of british columbia and alaska the cordillera of southern british columbia and the southern belt of the hercynian chain are examples where melt assisted rapid pulses of uplift appear to have occurred during the terminal phases of uplift and following uplift these orogenic belts were exhumed during extension while melt was still present

rock glacier dynamics in a marginal periglacial high mountain environment flow movement 1991 2000 and structure of the argualas rock glacier the pyrenees the argualas rock glacier is located on the southern side of the central pyrenees argualas massif vertical electric sounding debris surface analysis and a topographic survey were performed on this rock glacier between 1991 and 2000 high precision measurement records were obtained using a total station horizontal and vertical movements of the rock glacier were measured by means of sixteen steel rods horizontal and vertical angles and distances to each rod were measured from three stations on a bedrock ridge total and annual average displacements were derived from the emergence value and the horizontal displacement of each rod then the horizontal and vertical displacement rates in different sectors of the rock glacier were compared the inferred surface deformation was characterized by both extensional and compressive flows as well as thinning of the frozen body the displacement rates showed temporal variations related to atmospheric thermal changes pointing to a high sensibility of the rock glacier

the little ice age in iberian mountains abstract the little ice age lia is known as one of the coldest stages of the holocene most records from the northern hemisphere show evidence of significantly colder conditions during the lia which in some cases had substantial socio economic consequences in this study we investigated the magnitude and timing of climate variability during the lia in the mountains of the iberian peninsula based on a wide range of natural records including from glacial periglacial and lacustrine peatland areas fluvial alluvial deposits speleothems and tree rings historical documents and early instrument data the onset of the lia commenced in approximately ce 1300 and cold conditions with alternating moisture regimes persisted until approximately ce 1850 the environmental responses ranged from rapid e g tree rings to delayed e g glaciers the colder climate of the lia was accompanied by severe droughts floods and cold heat waves that showed significant spatio temporal variation across the iberian mountains several phases within the lia have been detected including a 1300 1480 increasing cooling with moderate climate oscillations b 1480 1570 relatively warmer conditions c 1570 1620 gradual cooling d 1620 1715 coldest climate period of the lia particularly during the maunder minimum with temperatures approximately 2 c below those at present e 1715 1760 warmer temperatures and a low frequency of extreme events f 1760 1800 climate deterioration and more climate extremes i e cold and heat waves floods and droughts g 1800 1850 highly variable climate conditions alternating with stability 1800 1815 extreme events 1815 1835 and a slight trend of warming associated with intense hydrometeorological events 1835 1850 h since 1850 a gradual staggered increase in temperature of approximately 1 c post lia warming has led to substantial changes in geo ecological dynamics mainly through shrinking of the spatial domain affected by cold climate processes

rock glacier dynamics in southern carpathian mountains from high resolution optical and multi temporal sar satellite imagery the dynamics of rock glaciers in marginal periglacial environments are poorly understood especially in eastern europe where the enhanced continentality produces a distinct pattern of periglacial phenomena multi temporal image analysis of high resolution optical and radar satellite imagery of the southern carpathian mountains romania revealed the small dynamic nature and a slow geomorphologic evolution of rock glaciers over a 46 yr period of record 1968 2014 nine rock glaciers located in glacial cirques and troughs within the central area of retezat mountain were included in this study overall the estimated displacement rates are extremely low i e a few cm year compared with other active rock glaciers from all over the world despite their relative attenuated activity it appears that judele valea rea and pietrele are still active rock glaciers but in an evident disequilibrium imbalance with the actual climate these findings document the lowest altitude and easternmost active rock glaciers at this latitude from europe quantitative investigations were concentrated on pietrele rock glacier subject of recent field campaigns optical data analysis indicated a slight acceleration of the horizontal velocities at the surface of pietrele rock glacier in recent years this acceleration appears to be caused by an increase in the temperature of permafrost resulting from an evident warming of external air temperature radar data analysis suggested seasonal variability of surface motion with higher deformation in autumn whereas in early summer or spring the deformation is negligible overall the results obtained with cross correlation analysis interferometric synthetic aperture radar insar coherence analysis and small baseline subset sbas multitemporal interferometry are consistent displaying similar deformation patterns with the highest creep rates located in the southern and western portions of the glacier these findings are supported by thermal and geophysical measurements which suggest the probable presence of permafrost within these areas the observed displacements were interpreted as permafrost creep and their very low velocity rates suggest the deforming frozen layers are very thin these results provide i baseline information and decadal scale trends and a ii strategy for future monitoring of the health and integrity of the rock glacier environment in the carpathian mountains