imaging and modeling the ionospheric airglow response over hawaii to the tsunami generated by the tohoku earthquake of 11 march 2011 1 although only centimeters in amplitude over the open ocean tsunamis can generate appreciable wave amplitudes in the upper atmosphere including the naturally occurring chemiluminescent airglow layers due to the exponential decrease in density with altitude here we present the first observation of the airglow tsunami signature resulting from the 11 march 2011 tohoku earthquake off the eastern coast of japan these images are taken using a wide angle camera system located at the top of the haleakala volcano on maui hawaii they are correlated with gps measurements of the total electron content from hawaii gps stations and the jason 1 satellite we find waves propagating in the airglow layer from the direction of the earthquake epicenter with a velocity that matches that of the ocean tsunami the first ionospheric signature precedes the modeled ocean tsunami generated by the main shock by approximately one hour these results demonstrate the utility of monitoring the earth s airglow layers for tsunami detection and early warning

planetary surface dating from crater size frequency distribution measurements partial resurfacing events and statistical age uncertainty abstract we describe the procedure to fit a cumulative production function polynomial to a partial crater size frequency distribution the technique is of particular use in deriving ages for surfaces which have undergone partial resurfacing events namely erosional or depositional events which have affected a limited diameter range of the crater population we demonstrate its use in obtaining times for both the surface formation and the resurfacing event we give a practical outline of the method for making age measurements from crater counts and how to identify resurfacing effects in the results we discuss the conversion of production function polynomials between common presentations and the statistical uncertainty of the determined ages with respect to the non linear chronology function and a minor refinement of data binning

geochemical evolution of the precambrian old rag granite virginia u s a testing a uth exploration model abstract the old rag granite is one of several recognized units within the virginia blue ridge complex generally composed of grenville age gneisses and granitoid intrusive rocks chemical variation in the old rag granite indicates simple orthomagmatic crystallization from the borders to the core of the pluton fractional crystallization of plagioclase oxides apatite and zircon accounts for much of the variation some trace elements however show anomalous behavior in the central part of the pluton y and sr and possibly ba and nb are enriched whereas rb and total ree are depleted in the central part of the pluton late crystallization of monazite could contribute to the observed ree patterns it could not however account for rb depletion and sr enrichment and no clear relationship between ree data and th u ratios are observed the geochemical patterns indicate overall orthomagmatic crystallization overlain by a late stage hydrothermal event an exploration model for uraniferous granites based upon the uranium deposits at rossing and bokan mountain included the precambrian basement of central and northern virginia in a list of proposed target areas geological mineralogical and whole rock chemical characteristics show a close association between the old rag granite and the rossing type deposits the uranium mean 6 9 ppm range 0 1 19 8 ppm and thorium mean 43 ppm range 3 5 114 ppm values are anomalous th u ratios average 7 5 and are widely variable indicating a decoupling of uranium from thorium neither u nor th are lognormally distributed within the old rag granite requiring an explanation beyond simple removal of u by weathering rayleigh fractionation modeling shows that both u and th although probably distributed originally by closed system fractionation have been subsequently mobilized uranium can be lost in an oxidized form by secondary processes such as weathering or hydrothermal alteration thorium however will be affected only by hydrothermal processes it is concluded that although primary fractionation was orthomagmatic the old rag granite was affected by late hydrothermal alteration whereby u was lost from the body and th was redistributed three primary avenues for u migration are possible 1 the rocks of the saddleback mountain intrusive suite which may have been contemporaneous with the old rag granite 2 paleozoic fault zones that cut the old rag pluton and 3 quartz veins pegmatites cupolas and roof pendants of the country rock nellysford gneiss that have been lost to erosion the last option is preferred on geological and geochemical grounds it is possible that the sedimentary uranium deposits of the adjacent triassic culpepper basin were derived from eroded upper levels of the old rag granite and like intrusives of the virginia blue ridge complex

the competition between thermal contraction and differentiation in the stress history of the moon the scarcity of both extension and compression features on the moon strongly constrains the history of the lunar radius to variations of less than 1 km over the past 3 8 gyr this limit has traditionally been interpreted as requiring a delicate balance between thermal contraction of the near surface and expansion of a substantial cold interior region recent theories of lunar origin e g giant impact in contrast favor a hot initial state we propose that a reconciliation may be possible by taking account of the volume change v v d due to differentiation we calculate stp densities based on simplified normative mineralogies for a suite of estimates of the bulk lunar composition of primary lunar basalt and of the residuum left when the maximum amount of the latter is extracted from the former typically v v d 2 to 5 an expansion equivalent to heating by 10 3 k provided the timing of differentiation is correct one might offset the cooling of a magma ocean as much as 630 km deep by differentiation of the remainder of the moon which need not start much below the solidus temperature a large but not impossible amount of gabbroic melt production is implied 100 times the volume of mare basalts known to have been extruded we do not address the detailed genetic relationship of this melt to the basalts observed on the lunar surface but point out that it need not have reached the surface directly or even have entered the crust in order for the expansion to have occurred to assess the timing of melt formation we investigate a simple conductive lunar thermal model which takes account of both v v d and thermal contraction our initial state is characterized by a central temperature t c and a depth z 0 above which the material derived from the magma ocean is already at the solidus and is not suceptible to volume changes upon further differentiation we find a range of models satisfying the limits on radius increase and decrease the hottest has t c 1210 k z 0 400 km without v v d we would need a larger or colder or both core e g t c 700 k for z0 200 400 km in agreement with previous investigators our modeling thus lends credence to the idea that the moon could have been initially 50 molten with the remainder relatively close to the solidus and yet experienced little volume change over the last 3 8 gyr

pore pressure stress increase and fault weakening in low angle normal faulting low angle dip 30 normal faults accommodate much extension of the continental crust they apparently move under low resolved shear stress and are anomalously weak characteristics that they share with the san andreas fault structural textural and geochemical arguments suggest that low angle normal faults are weak in both the ductile and brittle regimes partly or totally due to elevated pore fluid pressure high pore pressure in detachment zones may be contained by upper plate strata mineral precipitation in their hanging walls formation of low permeability microbreccia layers threshold pressure gradients and low permeability mylonites below chlorite breccia mechanical analysis shows that fault weakening may preclude equality of the regional and fault zone stress tensors and predicts reorientation and increase of principal stresses in weak fault zones these changes suppress hydraulic fracturing in the brittle detachment zone and allow slip under frictional sliding conditions typical of upper crustal rocks fault weakening focuses extension in the upper crust onto low angle normal ductile brittle shear zones in the midcrust promoting propagation of low angle brittle normal faults into the upper crust

concentric traveling ionosphere disturbances triggered by super typhoon meranti 2016 concentric traveling ionosphere disturbances ctids in total electron content tec triggered by super typhoon meranti on 13 september 2016 are detected using the ground based global navigation satellite system gnss network in taiwan the ctids emanated outwards before the typhoon landfall and lasted for more than 10 hours the characteristics of ctids agree with the gravity wave theory and exhibit spatial and temporal scales in wave periods of 8 30 minutes horizontal wavelengths of 160 200 km and horizontal phase velocities of 106 220 m s we also observe the ctids showing the stationary wave character broad spectra of ctids are excited after the rainbands of typhoon impinged on central mountain range cmr of taiwan the ray tracing technique confirms that the ctids were excited by convective clouds spiral rainbands and the eyewall of typhoon meranti this study provides new evidence of typhoon induced concentric gravity waves in the ionosphere

evidence of gravity wave ducting in the mesopause region from airglow network observations 1 we present observational evidence of gravity wave ducting and show for the first time that the ducting occurs over large horizontal distances in the mesopause region an optical network of four all sky imagers in japan identified two dimensional patterns of small scale gravity wave bands in oh airglow images on 13 june 2004 the wave signatures clearly showed northward propagation of more than 1800 km over a wide range of latitudes the horizontal wavelength horizontal phase speed and wave period were estimated from the airglow data as 33 4 km 42 8 m s 1 and 13 4 min respectively the wave structure lasted for the whole 5 h airglow observation period simultaneous mf radar wind data and timed saber measurements suggested that the wave was trapped and ducted at the airglow height the ducting likely contributed to the remarkable coherence of the wave as it propagated northward

simultaneous observations of storm generated sprite and gravity wave over bangladesh we report simultaneous observations of sprite and gravity wave generated by a storm over bangladesh the origin of a concentric gravity wave can be traced to the storm region on apr 27 2014 over bangladesh with a low cloud top surface temperature 175 k after data analysis the time period of the concentric gravity wave is found to be 8 8 8 9 minutes the horizontal wavelength is found to be 50 km for red emissions 55 km for green emissions and the horizontal phase velocity is 94 4 31 7 m s 1 for red emissions 102 6 29 4 m s 1 for green emissions using the dispersion relation of gravity wave the elevation angle of wave propagation direction is found to be 53 3 the sprite associated with the gravity wave was also recorded at 1534 ut on apr 27 2014 the initiation time of storm generated gravity wave is estimated to be 1454 ut at which lightning activity was relatively low using lightning data at time 1534 ut of the recorded sprite the lightning rate was close to its maximum value the storm generated gravity wave could be thought as a precursor phenomenon for lightning and sprites since one of the necessary conditions for gravity wave lightning and sprites is strong convection inside storms

morphometric analysis of small scale lobate scarps on the moon using data from the lunar reconnaissance orbiter 1 prior to lunar reconnaissance orbiter lro the morphology and dimensions of only a limited number of lobate scarps all located near the equator within 21 had been characterized topography derived from lro camera stereo images and lunar orbiter laser altimeter lola ranging is used to measure the relief and analyze the morphology of previously known and newly detected low and high latitude lobate scarps the asymmetric profiles and maximum slopes on scarp faces 5 to 29 of lunar lobate scarps are similar to those of lobate scarps observed on mars and mercury scarp lengths range from 0 6 to 21 6 km mean 6 0 km median 4 4 km n 79 and measured relief ranges from 5 to 150 m mean 35 m median 20 m n 26 assuming a range of 20 to 40 for the fault plane dip estimated lower limits for the horizontal shortening s expressed by the lobate scarp thrust faults range from 10 to 410 m the range in s estimated for the lunar scarps is roughly an order of magnitude lower than estimates of s for lobate scarp thrust faults on mars and mercury the relatively small range of s estimated for the growing number of well characterized lunar scarps is consistent with a small amount of global contraction

gld100 the near global lunar 100 m raster dtm from lroc wac stereo image data 1 we derived near global lunar topography from stereo image data acquired by the wide angle camera wac of the lunar reconnaissance orbiter camera lroc system from polar orbit tracks the lroc wac provides image data with a mean ground resolution at nadir of 75 m pixel with substantial cross track stereo overlap wac stereo images from the one year nominal mission and the first months of the science mission phase are combined to produce a near global digital terrain model dtm with a pixel spacing of 100 m the global lunar dtm 100 m or gld100 it covers 79 s to 79 n latitudes 98 2 of the entire lunar surface we compare the gld100 with results from previous stereo and altimetry based products particularly with the lunar orbiter laser altimeter lola altimetry which is the current topographic reference for the moon we describe typical characteristics of the gld100 and based upon the comparison to the lola data set assess its vertical and lateral resolution and accuracy we conclude that the introduced first version of the stereo based gld100 is a valuable topographic representation of the lunar surface complementary to the lola altimetry data set further improvements can be expected from continuative investigations

trace and rare earth element ree characteristics of mudstones from eocene pinghu formation and oligocene huagang formation in xihu sag east china sea basin implications for provenance depositional conditions and paleoclimate abstract the interpretation of depositional conditions provenance and paleoclimate provide important information to understand hydrocarbon source rock formation and distribution the concentrations of trace elements and rare earth elements rees of fifty mudstone samples from eocene pinghu formation and oligocene huagang formation in xihu sag east china sea basin were determined by inductively coupled plasma mass spectrometry icp ms to test the depositional conditions provenance and paleoclimate evidences from the visual comparisons of the simple bivariate plots diagrams and statistical comparisons of the mann whitney rank sum test suggest that there may be a common source for the pinghu formation and huagang formation mudstones sedimentary provenance from bivariate plots diagrams of hf versus la th and la sc versus co th shows that pinghu formation mudstones are mainly composed of mixed felsic basic source and acidic source whereas huagang formation is mainly acidic source additionally the ree vs la yb discrimination diagram shows that the property of the provenance for the pinghu formation mudstones consists sedimentary rock alkaline basalt and a small amount of continent tholeiitic basalts whereas that of the huagang formation is mainly alkaline basalt and sedimentary rock discriminant diagrams consisting of la th sc and th co zr 10 suggest that the mudstones of two formations were deposited in continental island arc and active continental margin tectonic setting redox proxies v ni v v ni and ce indicate that most of the mudstones of two formations were deposited in a relatively dysoxic anoxic condition the cool and humid climate represented by sr cu and rb sr ratios were prevailing in xihu sag during the eocene and oligocene period and the oligocene was cooler than eocene moreover five long term base level cycles siii1 siii5 and four sequence boundaries sb2 sb5 were recognized in the pinghu formation and huagang formation based on the previous research we find that the abnormal surfaces of geochemical parameters such as v ni sr ba u ti v ti ti and ree to some extent agree with sequence boundaries sb2 sb3 sb4 and sb5 in mudstones additionally the increment of ti and ree concentrations and the decrease of sr ba v ni u ti and v ti ratios above the sb4 indicates that terrigenous clast grew significantly and the sea level dropped after late eocene which is related with the late eocene tectonic movement

global thrust faulting on the moon and the influence of tidal stresses lunar reconnaissance orbiter camera images reveal a vast globally distributed network of over 3200 lobate thrust fault scarps making them the most common tectonic landform on the moon based on their small scale and crisp appearance crosscutting relations with small diameter impact craters and rates of infilling of associated small shallow graben these fault scarps are estimated to be younger than 50 ma and may be actively forming today the non random distribution of the scarp orientations is inconsistent with isotropic stresses from late stage global contraction as the sole source of stress we propose that tidal stresses contribute significantly to the current stress state of the lunar crust orbital recession stresses superimposed on stresses from global contraction with the addition of diurnal tidal stresses result in non isotropic compressional stress and thrust faults consistent with lobate scarp orientations the addition of diurnal tidal stresses at apogee result in peak stresses that may help trigger coseismic slip events on currently active thrust faults on the moon

india eurasia collision chronology has implications for crustal shortening and driving mechanism of plates the motion of the indian plate is determined in an absolute frame of reference and compared with the position of the southern margin of eurasia deduced from palaeomagnetic data in tibet the 2 600 900 km of continental crust shortening observed is shown to have occurred in three different episodes subduction of continental crust intracontinental thrusting and internal deformation and lateral extrusion the detailed chronology of the collision and plate reorganizations in the indian and pacific oceans supports the hypothesis that slab pull is a dominant driving mechanism of plate tectonics

lunar mare basalt flow units thicknesses determined from crater size frequency distributions accurate lava flow unit thicknesses estimates are necessary to place constraints on volcanic flux estimates we refine the technique of using the shape of crater size frequency distribution csfd curves to estimate the thickness of individual lunar mare flow units we find that a characteristic knee often observed in csfd curves is reasonably interpreted to represent the presence of two lava flow units separated in time and that the diameter at which this knee occurs is related to the thickness of the overlying flow unit examination of 58 curves with this characteristic knee in several lunar nearside basins oceanus procellarum imbrium tranquillitatis humorum cognitum nubium and insularum allowed us to identify flow units that have not been detected in low sun images we found that the range of flow unit thickness is 20 220 m and the average is 30 60 m this technique expands considerably the ability to assess lava flow unit thicknesses and volumes on the moon and planets

rare earth element mobility in the oceanic lower sheeted dyke complex evidence from geochemical data and leaching experiments hydrothermally altered rocks from the base metal depleted reaction zone in the lower sheeted dyke complex odp hole 504b show significant losses of rare earth elements ree in extensively altered domains alteration patches while very similar in major element composition and alteration mineralogy the alteration patches have up to 50 lower ree concentrations than the surrounding weakly altered diabases in order to test if there is a dependence of ree mobility on the alteration history we carried out leaching experiments on a weakly altered diabase and an adjacent alteration patch the leaching experiments are used as a probe to identify the hosting phases of major and trace elements before and after alteration they are not designed to simulate natural alteration processes major element compositions of the leaching solutions show that small amounts 9 to 14 of the rocks and similar proportions of plagioclase amphibole and chlorite were dissolved from both rock types in contrast to the major elements up to 100 of the ree could be leached from the strongly recrystallised alteration patch after 20 h all leaching solutions were light ree enriched and had negative eu anomalies compared to the host rock geochemical modelling suggests that mainly interstitial material formerly late stage magmatic liquids and probably some apatite are the main ree sources in the rocks affected during experimental leaching dissolution of plagioclase amphibole clinopyroxene and chlorite cannot explain the ree compositions of the leachates the higher ree leachability of the heavily altered rock suggests that the extensive hydrothermal alteration resulted in a complete redistribution of the ree from lattices of the magmatic minerals to the grain boundaries of secondary minerals this can explain the marked increase in ree accessibility during ongoing alteration which finally led to ree depletions in the highly altered rock we propose that late stage interstitial material provides the most important ree source of rocks in the oceanic crust this interpretation is in contrast to a model by klinkhammer et al klinkhammer g p elderfield h edmond j m mitra a 1994 geochemical implications of rare earth element patterns in hydrothermal fluids from mid ocean ridges geochim cosmochim acta vol 58 pp 5105 5113 who suggested that the similarity in the ree patterns of plagioclase and that of hydrothermal vent fluids is a result of chemical exchange between plagioclase and hot fluids in the ocean crust our leaching results indicate that although dramatic dissolution of plagioclase occurred it did not control the ree patterns of the leachates moreover ree patterns inferred for fluids that mobilised ree from the highly altered rock are different from those of vent fluids we therefore propose that the characteristic ree pattern of vent fluids may result from differences in aqueous chloride complex stabilities sorption controlled ree fractionation during fluid migration and mineral precipitation in the discharge zone

changes in fault displacement populations correlated to linkage between faults in carboniferous strata exposed at the western margin of the southern appalachian u s a fold thrust belt mesoscopic faults accommodated strains as the cumberland plateau thrust sheet moved 1 km wnw on a sub horizontal detachment these faults are confined to a layer 75 m thick above the detachment in the upper part of this 75 m thick layer a laterally persistent coal seam separates two stratigraphic units subjected to different amounts of sub horizontal elongation distinct sets of mesoscopic faults that cut bedding at high angles and have normal offsets accommodate the strains in each unit below the coal seam a sample line 500 m long intersects 504 faults a plot of log n size rank vs log d dip separation in mm for these faults is linear suggesting that a scaling law n ad c holds for this population least squares regression gives c 0 8 and log10 a 3 1 above the coal seam a sample line 250 m long intersects 745 faults a plot of log n vs log d for these faults has two distinct linear trends faults with separations 1 25 m yield a scaling law n ad c with c 0 5 and log10 a 2 9 seventeen faults with separations d 1 25 m define a second linear segment n a d c with c 1 8 and log10 a 6 9 the break in slope at d 1 25 m corresponds to faults with heights of 30 m roughly equal to the thickness of the faulted strata faults here with d 1 25 m and d 1 25 m which exhibit different scaling characteristics are respectively analogous to faults within and those that extend across the brittle crust in regional studies comparing the two displacement populations described here small offset faults make a proportionally smaller contribution to the total strain in the larger strain setting this pattern which is observed elsewhere suggests that fault systems within individual layers exhibit different scaling characteristics at different stages in their history this contribution argues that fault linkage is the key to such changes in fault scaling behavior it is a mesoscopic to macroscopic structural change that alters the subsequent development of faults fault linkage like fault size or sampling dimension should be considered in examinations of fault scaling laws

forming a moon with an earth like composition via a giant impact in the giant impact theory the moon formed from debris ejected into an earth orbiting disk by the collision of a large planet with the early earth prior impact simulations predict that much of the disk material originates from the colliding planet however earth and the moon have essentially identical oxygen isotope compositions this has been a challenge for the impact theory because the impactor s composition would have likely differed from that of earth we simulated impacts involving larger impactors than previously considered we show that these can produce a disk with the same composition as the planet s mantle consistent with earth moon compositional similarities such impacts require subsequent removal of angular momentum from the earth moon system through a resonance with the sun as recently proposed

displacement length relations of thrust faults associated with lobate scarps on mercury and mars comparison with terrestrial faults the displacement dand length lof thrust faults associated with lobate scarps on mercury and mars are estimated from topographic and planimetric measurements dranges from 0 29 to 3 58 km for mercurian thrust faults n 10 and from 0 27 km to 2 90 km for martian thrust faults n 13 the d lrelationship between thrust fault populations analyzed on mercury and mars is very similar mercury 6 5 3 2 10 3 mars 5 9 2 0 10 3 and about an order of magnitude lower than terrestrial thrust faults the difference is probably dominated by the contrast in tectonic setting between terrestrial thrust faults and those on mercury and mars the similarity in morphology and the d lrelationship of the mercurian and martian thrust faults may be due to the similarity in mechanical properties of the deformed materials and the acceleration due to gravity of the two planets

constraints on deep moonquake focal mechanisms through analyses of tidal stress 1 a relationship between deep moonquake occurrence and tidal forcing is suggested by the monthly periodicities observed in the occurrence times of events recorded by the apollo passive seismic experiment in addition the typically large s wave to p wave arrival amplitude ratios observed on deep moonquake seismograms are indicative of shear failure tidal stress induced in the lunar interior by the gravitational influence of the earth may influence moonquake activity we investigate the relationship between tidal stress and deep moonquake occurrence by searching for a linear combination of the normal and shear components of tidal stress that best approximates a constant value when evaluated at the times of moonquakes from 39 different moonquake clusters we perform a grid search at each cluster location computing the stresses resolved onto a suite of possible failure planes to obtain the best fitting fault orientation at each location we find that while linear combinations of stresses and in some cases stress rates can fit moonquake occurrence at many clusters quite well for other clusters the fit is not strongly dependent on plane orientation this suggests that deep moonquakes may occur in response to factors other than or in addition to tidal stress several of our inferences support the hypothesis that deep moonquakes might be related to transformational faulting in which shear failure is induced by mineral phase changes at depth the occurrence of this process would have important implications for the lunar interior

misoriented faults in exhumed metamorphic complexes rule or exception abstract low angle normal faults and other weak faults are common in the metamorphic core of collisional orogens they frequently show a phyllosilicate rich mylonitic foliation that was reactivated under brittle conditions experimental and theoretical works indicate that mechanical anisotropies exert a substantial influence on shear failure and frictional sliding eventually inhibiting the nucleation and propagation of new andersonian shear fractures and favoring the localization of brittle failure along the pre existing foliations metamorphic phyllosilicate rich rocks may show a friction coefficient varying from 0 6 at high angles to the foliation to 0 2 0 4 for shear along the inherited foliation to test the influence of mechanical anisotropies on the development of non andersonian faults we have applied a modified slip tendency analysis to three misoriented phyllosilicate rich faults of the european alps the analysis accounts for anisotropy in friction coefficients and has been named anisotropic slip tendency analysis here we show that brittle deformation along misoriented phyllosilicate rich foliations is more probable than the development of new andersonian faults the presence of a well developed network of weak phyllosilicate rich faults may influence the overall structural style and mechanical properties of the brittle lithosphere in collisional orogens

how old are lunar lobate scarps 1 seismic resetting of crater size frequency distributions abstract previous studies have estimated the ages of lunar lobate scarps some of the youngest tectonic landforms on the moon based on the estimated life times of their fresh morphologies and associated small graben using crater degradation ages or via buffered and traditional crater size frequency distribution csfd measurements here we reexamine five scarps previously dated by binder and gunga 1985 with crater degradation ages to benchmark the evaluation of both the buffered and traditional csfd approaches for determination of absolute model ages amas at scarps both csfd methods yield similar ages for each individual scarp indicating that fault activity not only can be measured on the scarp itself but also in the surrounding terrain an indication that tectonic activity causes surface renewal both adjacent to and even kilometers distant from scarps size frequency variations in the regions surrounding the scarps are thus useful for studying the extent and severity of the ground motion caused by coseismic slip events during scarp formation all age determination approaches continue to indicate that lunar lobate scarps were active in the late copernican with some scarps possibly experiencing activity within the last 100 ma

the origin of neotectonics on the lunar nearside new observations of wrinkle ridges on the nearside maria of the moon display signs of ongoing ridge modification in association with the wrinkle ridges we observed an absence of superposed craters narrow 30 m lobate scarps and graben and thermal anomalies related to exposures of meter size blocks many of these active wrinkle ridge systems are well beyond the influence of mascon basins and unrelated to any global tectonic pattern nevertheless they spatially correlate with ancient deep seated dike intrusions on the lunar nearside revealed by gravity data analysis we propose that this active nearside tectonic system ants reflects ongoing reactivation of an ancient system related to offset antipodal effects from the south pole aitken basin

length displacement scaling of thrust faults on the moon and the formation of uphill facing scarps abstract fault populations on terrestrial planets exhibit a linear relationship between their length l and the maximum displacement d which implies a constant d l ratio during fault growth although it is known that d l ratios of faults are typically a few percent on earth and 0 2 0 8 on mars and mercury the d l ratios of lunar faults are not well characterized quantifying the d l ratios of faults on the moon is however crucial for a better understanding of lunar tectonics including for studies of the amount of global lunar contraction here we use high resolution digital terrain models to perform a topographic analysis of four lunar thrust faults simpelius 1 morozov s1 fowler and racah x 1 that range in length from 1 3 km to 15 4 km first we determine the along strike variation of the vertical displacement from 20 topographic profiles across each fault for measuring the vertical displacements we use a method that is commonly applied to fault scarps on earth and that does not require detrending of the profiles the resulting profiles show that the displacement changes gradually along these faults strike with maximum vertical displacements ranging from 17 2 m for simpelius 1 to 192 30 m for racah x 1 assuming a fault dip of 30 yields maximum total displacements d that are twice as large as the vertical displacements the linear relationship between d and l supports the inference that lunar faults gradually accumulate displacement as they propagate laterally for the faults we investigated the d l ratio is 2 3 an order of magnitude higher than theoretical predictions for the moon but a value similar for faults on earth we also employ finite element modeling and a mohr circle stress analysis to investigate why many lunar thrust faults including three of those studied here form uphill facing scarps our analysis shows that fault slip is preferentially initiated on planes that dip in the same direction as the topography because the reduced overburden increases the differential stress on prospective fault planes and hence promotes failure our findings highlight the need for quantifying vertical displacements of more lunar thrust fault scarps with the methodology employed in this study rather than relying only on measurements of local relief which result in d l ratios that tend to be too low

multiple controls on the preservation of organic matter in devonian mississippian marine black shales geochemical and petrographic evidence geochemical and petrographic analysis of an interval of black shales between the huron shale member of the new albany shale upper devonian famennian and the sunbury shale lower mississippian tournaisian suggests that multiple controls influenced the accumulation of organic matter stratigraphic trends were determined following detailed analysis of a core from the central appalachian basin d6 montgomery county ky specifically c s fe relationships mo v v ni ni co and v cr were used to assess paleo redox conditions during sediment accumulation the role of clastic input was evaluated using ti al k al and si al and c p was used as a proxy for paleoproductivity the terrestrial to marine maceral ratio t m vitrinite plus inertinite alginite plus bituminite was used to evaluate changes in om source c s fe relationships and trace element ratios suggest anoxic conditions prevailed during deposition of much of the upper part of this interval however bottom water conditions were intermittently dysoxic during accumulation of the huron shale member and possibly dysoxic to marginally oxic during accumulation of the lowermost huron shale member productivity appears to have been an important factor in the accumulation of corg and high c p ratios are consistent with a productivity anoxia feedback mechanism in addition nutrients from increased terrestrial weathering may have contributed to enhanced productivity variations in sediment influx may also have influenced corg concentrations through sediment starvation one of the more significant observations in this work is an increase in terrestrial om inertinite and vitrinite up section which may reflect vegetative changes occurring on land during this time interval most of this increase is due to inertinite much of which appears to be fusinitic in origin and hence may be fossil charcoal this latter observation has implications for the expansion of land plants into drier niches and for late devonian atmospheric oxygen levels introduction of more resistant terrestrial om to anoxic basins may have been an important factor in the preservation of high carbon 10 intervals especially in the cleveland member of the new albany shale upper devonian famennian and the sunbury shale lower mississippian tournaisian

ages of mare basalts on the lunar nearside the chronology of lunar volcanism is based on radiometric ages determined from apollo and luna landing site samples regional stratigraphic relationships and crater degradation and size frequency distribution data for units largely defined prior to the end of the apollo program here we report on new crater size frequency distribution data for 139 spectrally and morphologically defined basalt units which are exposed in six nearside impact basins australe tranquillitatis humboldtianum humorum serenitatis and imbrium crater size frequency distribution measurements are a statistically robust and accurate method to derive absolute model ages of unsampled regions of the moon compared to crater degradation ages crater size frequency ages performed on spectrally defined units offer significant improvements in accuracy our investigation showed that 1 in the investigated basins lunar volcanism was active for at least 1 5 2 0 b y starting at about 3 9 4 0 b y and ceasing at 2 0 b y 2 most basalts erupted during the late imbrian period at about 3 6 3 8 b y 3 significantly fewer basalts were emplaced during the eratosthenian period 4 basalts of copernican age were not found in any of the investigated basins 5 lunar basin filling volcanism probably started within 100 m y after the formation of the individual basins we also assessed the relationship between impact basin age and the history of mare basalt emplacement in these basins we found that 1 in all pre nectarian basins australe and tranquillitatis as well as in the humboldtianum basin which is of nectarian age the distribution of surface ages is clearly dominated by only a single peak in the number of erupted units at 3 6 3 8 b y 2 in the younger basins humorum serenitatis and imbrium a second peak at 3 3 3 5 b y is observed 3 basalt eruptions younger than 2 6 b y occur only intermittently and 4 in the youngest basins serenitatis and imbrium we see an extended period of active basin filling volcanism 1 5 1 6 b y which is 500 m y longer than in the australe and humorum and even 1 0 b y longer than in tranquillitatis and humboldtianum

fault dislocation modeled structure of lobate scarps from lunar reconnaissance orbiter camera digital terrain models 1 before the launch of the lunar reconnaissance orbiter known characteristics of lobate scarps on the moon were limited to studies of only a few dozen scarps revealed in apollo era photographs within 20 of the equator the lunar reconnaissance orbiter camera now provides meter scale images of more than 100 lobate scarps as well as stereo derived topography of about a dozen scarps high resolution digital terrain models dtms provide unprecedented insight into scarp morphology and dimensions here we analyze images and dtms of the slipher racah x 1 mandel shtam 1 feoktistov simpelius 1 and oppenheimer f lobate scarps parameters in fault dislocation models are iteratively varied to provide best fits to dtm topographic profiles to test previous interpretations that the observed landforms are the result of shallow low angle thrust faults results suggest that these faults occur from the surface down to depths of hundreds of meters have dip angles of 35 40 and have typical maximum slips of tens of meters these lunar scarp models are comparable to modeled geometries of lobate scarps on mercury mars and asteroid 433 eros but are shallower and 10 steeper than geometries determined in studies with limited apollo era data frictional and rock mass strength criteria constrain the state of global differential stress between 3 5 and 18 6 mpa at the modeled maximum depths of faulting our results are consistent with thermal history models that predict relatively small compressional stresses that likely arise from cooling of a magma ocean

simultaneous observations of convective gravity waves from a ground based airglow imager and the airs satellite experiment 1 we report the first joint observations of convectively generated gravity waves gws using an oh airglow imager in colorado and the atmospheric infrared sounder airs onboard the aqua satellite convective gws appearing as concentric rings are observed over the western great plain regions of north america in the evening of 3 june 2008 in the airglow images inspecting both weather radars and airs radiances at 8 1 m strong convective clouds are found near the center of the concentric rings the airs data at 4 3 m show semicircular gws with horizontal wavelengths of 60 80 km at 0900 ut whereas the airglow imager observed circular gws with horizontal wavelengths of 44 km and airglow emission perturbation of 6 at the same geographic location at 0910 ut large scale gws horizontal wavelengths greater than 100 km emanating northwestward can be seen in both airs data and airglow images at different times the imager observed small scale ripples associated with unstable concentric gws in the mesopause in the early evening given that the brightness temperature perturbation of the gws in the airs data is about 0 16 k and assuming that the gws propagate without dissipation from the stratosphere to the upper mesosphere the expected airglow emission perturbation caused by the gws would be 4 17 ray tracing simulations are performed to demonstrate that the gws seen in airs and in the imager were likely excited by the same convective system

gravity waves generated by convection in the darwin area during the darwin area wave experiment 1 we describe a model study of gravity wave generation by convection near darwin during the darwin area wave experiment dawex we focus on an 7 hour period on 17 november 2001 for our study which included a major hector event over the tiwi islands followed by a continental convective outbreak that included a squall line to the southeast of darwin our model is a dry version of a three dimensional 3 d mesoscale cloud resolving model with horizontally uniform background wind and stability fields the model is forced with a spatially and temporally varying heating field representative of the convective latent heating in the area we derive this heating field from 3 d volumetric reflectivity from the precipitation radar located just north of darwin at gunn point during dawex the conversion from radar reflectivity to a 3 d latent heating field requires numerous assumptions that do not allow a quantitative heating estimate but which do provide a very realistic measure of the spatial morphology and temporal variations of the latent heating gravity waves generated by convective heating are known to be very sensitive to these characteristics of the heating so our resulting wave field is likely to be the most realistic possible description of the waves emitted from convection in the darwin area uncertainty in the wave amplitudes is large both because the input forcing heating is uncertain and because the use of heating as the sole proxy for wave forcing leads to additional wave amplitude errors we therefore compare the results of the model to other dawex measurements and previous modeling studies both to validate the waves in our model and to calibrate the wave amplitudes our study in turn aids in the interpretation of the other gravity wave measurements during dawex

increased seasonality through the eocene to oligocene transition in northern high latitudes a profound global climate shift took place at the eocene oligocene transition approximately 33 5 million years ago when cretaceous early palaeogene greenhouse conditions gave way to icehouse conditions during this interval changes in the earth s orbit and a long term drop in atmospheric carbon dioxide concentrations resulted in both the growth of antarctic ice sheets to approximately their modern size and the appearance of northern hemisphere glacial ice however palaeoclimatic studies of this interval are contradictory although some analyses indicate no major climatic changes others imply cooler temperatures increased seasonality and or aridity climatic conditions in high northern latitudes over this interval are particularly poorly known here we present northern high latitude terrestrial climate estimates for the eocene to oligocene interval based on bioclimatic analysis of terrestrially derived spore and pollen assemblages preserved in marine sediments from the norwegian greenland sea our data indicate a cooling of approximately 5 degrees c in cold month winter mean temperatures to 0 2 degrees c and a concomitant increased seasonality before the oi 1 glaciation event these data indicate that a cooling component is indeed incorporated in the delta 18 o isotope shift across the eocene oligocene transition however the relatively warm summer temperatures at that time mean that continental ice on east greenland was probably restricted to alpine outlet glaciers

shear veins observed within anisotropic fabric at high angles to the maximum compressive stress some faults seem to slip at unusually high angles 45 relative to the orientation of the greatest principal compressive stress1 2 3 4 5 this implies that these faults are extremely weak compared with the surrounding rock6 laboratory friction experiments and theoretical models suggest that the weakness may result from slip on a pre existing frictionally weak surface7 8 9 weakening from chemical reactions10 elevated fluid pressure11 12 13 or dissolution precipitation creep14 15 here we describe shear veins within the chrystalls beach accretionary melange new zealand the melange is a highly sheared assemblage of relatively competent rock within a cleaved anisotropic mudstone matrix the orientation of the shear veins compared with the direction of hydrothermal extension veins that formed contemporaneously indicates that they were active at an angle of 80 5 to the greatest principal compressive stress we show that the shear veins developed incrementally along the cleavage planes of the matrix thus we suggest that episodic slip was facilitated by the anisotropic internal fabric in a fluid overpressured heterogeneous shear zone a similar mechanism may accommodate shear at high angles to the greatest principal compressive stress in a range of tectonic settings we therefore conclude that incremental slip along a pre existing planar fabric coupled to high fluid pressure and dissolution precipitation creep may explain active slip on severely misoriented faults

first spaceborne observation of the entire concentric airglow structure caused by tropospheric disturbance spaceborne imagers are able to observe the airglow structures with wide field of views regardless of the tropospheric condition that limits the observational time of the ground based imagers concentric wave structures of the o2 airglow in 762 nm wavelength were observed over north america on 1 june 2013 from the international space station this was the first observation in which the entire image of the structure was captured from space and its spatial scale size was determined to be 1200 km radius without assumptions the apparent horizontal wavelength was 80 km and the amplitude in the intensity was approximately 20 of the background intensity the propagation velocity of the structure was derived as 125 62 m s and atmospheric gravity waves were estimated to be generated for 3 5 1 7 h concentric structures observed in this event were interpreted to be generated by super cells that caused a tornado in its early phase

investigation of newly discovered lobate scarps implications for the tectonic and thermal evolution of the moon abstract using observations of lunar scarps in apollo panoramic camera photos binder and gunga 1985 tested competing models for the initial thermal state of the moon i e whether it was initially completely molten or if the molten portion was limited to a global magma ocean binder and gunga 1985 favored the concept of an initially molten moon that had entered into a late stage epoch of global tectonism since the start of the lunar reconnaissance orbiter mission thousands of new small lobate scarps have been identified across the lunar surface with high resolution images from the lunar reconnaissance orbiter camera lroc as such we selected spatially random scarps and reevaluated the fault dynamical calculations presented by binder and gunga 1985 additionally we examined the geometry and properties of these fault scarps and place better constraints on the amount of scarp related crustal shortening we found that these low angle thrust faults 23 have an average relief of 40 m and average depths of 951 m using crater size frequency distribution csfd measurements we derived absolute model ages for the scarp surfaces proximal to the trace of the fault and found that the last slip event occurred in the last 132 ma along with young model ages lunar lobate scarps exhibit a youthful appearance with their crisp morphologies which is indicative of late stage horizontal shortening in conclusion interior secular cooling and tidal stresses cause global contraction of the moon

lobate scarps and the martian crustal dichotomy landforms reflecting crustal shortening are found in the ancient highlands of the eastern hemisphere of mars these structures referred to as lobate scarps are interpreted to be thrust faults lobate scarps occur near and are oriented roughly parallel to the martian crustal dichotomy a major geologic and topographic boundary that divides the heavily cratered highlands from the relatively smooth featureless northern lowlands the long and short wavelength topography of lobate scarps in the northern terra cimmeria amenthes region have been analyzed using photoclinometry earth based radar altimetry and mars orbiter laser altimeter data the measured relief of lobate scarps in this region ranges from 110 to 1230 m and they occur on gentle regional slopes that dip both toward and away from the dichotomy estimates of the horizontal shortening across the lobate scarps studied range from roughly 0 24 to 2 6 km n 9 assuming fault plane dips of 25 the displacement length d l relationships of thrust faults associated with the lobate scarps are consistent with those observed for terrestrial fault populations the compressional strain in the heavily cratered highlands near the dichotomy determined using the d l data for the lobate scarps is estimated to be 0 17 topographic data indicate that the dichotomy in the northern terra cimmeria amenthes region has a distinct topographic signature the spatial and temporal relationship of the lobate scarps to the boundary suggests that they are related to its formation supporting models for a tectonic origin of the crustal dichotomy

recent extensional tectonics on the moon revealed by the lunar reconnaissance orbiter camera on the moon extensional tectonic features have only been observed close to the influence of the mare basalt filled basins and floor fractured craters analysis of lunar reconnaissance orbiter camera images reveals several potentially very young extensional tectonic features in the farside highlands implying that extensional stresses may locally exceed compressional ones

trace elements as palaeoenvironmental markers in strongly mature hydrocarbon source rocks the cretaceous la luna formation of venezuela abstract the late cretaceous la luna formation is the main hydrocarbon source rock formation in venezuela in the lake maracaibo area the formation shows a steep maturation gradient affecting sedimentary organic matter om and clay minerals related to local burial history and thrusting events the influence of the gradient is examined through geochemical organic and inorganic and mineralogical investigations carried out on samples from five cored boreholes in the maracaibo basin the analytical procedure comprises rock eval pyrolysis vitrinite reflectance measurement palynofacies observation major and trace element content determination performed on bulk rock samples or after a sequential leach protocol dop calculation and the examination and analysis of clay mineral assemblages the maturation gradient seems to have had no effect upon the distribution of the trace elements referred to as proxy indicators for palaeodepositional conditions of om rich sediments ba p v mo ni co cu cd cr and mn consequently trace elements appear to be reliable palaeoenvironmental markers they indicate that during the la luna fm deposition the water column must have had variable conditions with high primary production near the surface and the correlative development of euxinic conditions at the bottom this provides further arguments for an upwelling system affecting the northern platform of south america during late cretaceous time the relative scarcity of reactive iron in the depositional environment must have taken an active part in a process involving sulphur and acting on the environmental conditions as well as on om vulcanisation this process favours aliphatic om storage and may be relevant for many other om rich facies or hydrocarbon source rocks

concentric waves and short period oscillations observed in the ionosphere after the 2013 moore ef5 tornado 1 we detected clear concentric waves and short period oscillations in the ionosphere after an enhanced fujita scale ef 5 tornado hit moore oklahoma u s on 20 may 2013 using dense wide coverage ionospheric total electron content tec observations in north america these concentric waves were nondispersive with a horizontal wavelength of 120 km and a period of 13 min they were observed for more than 7 h throughout north america tec oscillations with a period of 4 min were also observed to the south of moore for more than 8 h a comparison between the tec observations and infrared cloud image from the goes satellite indicates that the concentric waves and short period oscillations are caused by supercell induced atmospheric gravity waves and acoustic resonances respectively this observational result provides the first clear evidence of a severe meteorological event causing atmospheric waves propagating upward in the upper atmosphere and reaching the ionosphere

rare earth element geochemistry of australian paleozoic graywackes and mudrocks provenance and tectonic control abstract in the paleozoic graywackes of eastern australia there is an increase in the total abundance of rare earth elements ree a light to heavy ree ratio and a decrease in the chondrite normalized eu anomaly with the increase in sio2 al2o3 and k2o na2o ratios this is due to the change in the dominant source rocks from andesite to dacite to granite gneiss and sedimentary rocks similarly an increase in total ree and a decrease in eu anomaly is also seen in the associated mudrocks with the increase in total clay content this correlation in paleozoic sedimentary rocks suggests that the ree characteristics of terrigenous sedimentary rocks reflect the depositional tectonic setting of the basin the oceanic island arc type graywackes are characterised by their lower total ree abundance only slight enrichment of lree over hree and the absence of a negative eu anomaly on chondrite normalised plots the continental island arc type graywackes are discriminated by their higher ree abundance and la yb ratio the presence of a small negative eu anomaly on the chondrite normalised plots and the significant enrichment of eu compared to paas post archean average australian shale the sedimentary rocks deposited on andean type active continental margins passive margins platform and cratonic basins are all characterised by the high enrichment of lree over hree and the presence of a pronounced negative eu anomaly on chondrite normalised plots and can not be discriminated from each other by ree patterns alone

evidence of recent thrust faulting on the moon revealed by the lunar reconnaissance orbiter camera lunar reconnaissance orbiter camera images reveal previously undetected lobate thrust fault scarps and associated meter scale secondary tectonic landforms that include narrow extensional troughs or graben splay faults and multiple low relief terraces lobate scarps are among the youngest landforms on the moon based on their generally crisp appearance lack of superposed large diameter impact craters and the existence of crosscut small diameter impact craters identification of previously known scarps was limited to high resolution apollo panoramic camera images confined to the equatorial zone fourteen lobate scarps were identified seven of which are at latitudes greater than 60 indicating that the thrust faults are globally distributed this detection coupled with the very young apparent age of the faults suggests global late stage contraction of the moon

mesospheric concentric gravity waves generated by multiple convective storms over the north american great plain 1 we report on six continuous hours of oh airglow imager observations at z 87 km of convectively generated gravity waves gws near fort collins colorado on the evening of 08 september 2005 these gws appeared as nearly concentric rings and had epicenters near the locations of deep convection in three thunderstorms in colorado nebraska and south dakota using goes satellite and weather radar observations we show that the gws closely follow the thunderstorms using the background wind from a nearby radar the intrinsic wave parameters and vertical wavelengths are calculated the temperature perturbations are estimated to be t t 1 3 for gws with horizontal wavelengths h 20 40 km and horizontal phase speeds 40 60 m s the horizontal wavelengths of gws from a convective cluster decreased in time from 30 to 15 km we employ convective plume and ray trace models to simulate the gw induced oh intensity perturbations from convective plumes clusters and complexes we find that the results using the background model wind radiosonde time gcm agree well with the late time observations when the images are dominated by southwestward short wavelength high frequency gws these late time gws propagate against the background wind and have h 30 40 km and periods of 20 30 min the oh intensity perturbations are enhanced because the vertical wavelengths z increased t t increased and the vertical velocity perturbations w decreased because the gws were near their reflection levels we also find that these short wavelength gws were created 5 h earlier by an extremely energetic deep convective plume in south dakota thereby showing that small scale convective gws directly link the troposphere and mesopause region

concentric gravity waves in the mesosphere generated by deep convective plumes in the lower atmosphere near fort collins colorado 1 gravity waves in the mesopause region 80 105 km may induce perturbations in oh meinal band emissions at 87 km these perturbations can be observed by ground based oh airglow imagers in this paper we present observations of concentric gravity waves cgw by the all sky oh imager at yucca ridge field station 40 7 n 104 9 w near fort collins colorado we find that expanding rings of concentric gravity waves were observed on 9 out of 723 clear nights from 2003 to 2008 in particular on 11 may 2004 concentric rings were observed for 1 5 h with nearly perfect circular rings entirely in the field of view during the first 30 min the centers of the concentric rings occurred at the geographic locations of two strong convective plumes which were active in the troposphere 1 h earlier we measured the horizontal wavelengths and periods of these gravity waves as functions of both radius and time these results agreed reasonably well with the internal boussinesq gravity wave dispersion relation with an assumed zero background wind similarly for the other 8 cases strong convective plumes occurred prior to the cgw observations near the apparent center of each of the arcs or rings for the 7 out of the 9 cases radiosonde data were available up to z 30 35 km these data showed that the wind speeds from the tropopause to 30 35 km were smaller than 20 30 m s because 8 of the 9 cases occurred when the total horizontal mean winds were weak and because the horizontal winds below 87 km were less than 20 m s on 11 may 2004 according to radiosonde and time gcm model data we postulate that weak background horizontal winds are likely a necessary condition for gravity waves excited from convective overshooting to be observed as concentric arcs or rings in the oh layer