reconstruction of the holocene coastal development at fulong beach in north eastern taiwan using optically stimulated luminescence osl dating abstract the fulong beach coastal area represents a unique feature in taiwan comprising a beach only a few kilometres long and dominated by medium and fine grained quartz rich sand located in the estuary of shuangsi river the area is influenced by fluvial marine and aeolian processes which led to the development of coastal parallel dune ridges and a large sand complex to the south of the river during the holocene the island of taiwan is also influenced by tectonic activity with high uplift rates and a substantial number of earthquakes each year furthermore the subtropical climate and the occurrence of monsoon precipitation as well as typhoon events induce high erosion rates in the coastal zone seventeen samples from five sites were taken for grain size analyses and for optically stimulated luminescence osl dating post ir pulsed blue osl signals were measured to determine the depositional ages of the samples a chronological model of holocene coastal evolution of fulong beach and the main controlling factors was established sediment accumulation at fulong beach was initiated around 5130 360 a under sub aquatic conditions followed by beach deposition at around 3450 240 a the deposition of aeolian sediments started at around 3020 180 a and was interrupted by three depositional hiatuses during which palaeosols formed the dune ridges yielded osl ages between 60 20 and 690 70 a which indicate stabilisation of the morphological system of fulong beach only a few hundred years ago based on the new data the holocene uplift rate is 1 9 mm y for the last 3000 years at fulong beach incorporating the effects of holocene sea level fluctuations

space weathered rims found on the surfaces of the itokawa dust particles on the basis of observations using cs corrected stem we identified three types of surface modification probably formed by space weathering on the surfaces of itokawa particles they are 1 redeposition rims 2 3 nm 2 composite rims 30 60 nm and 3 composite vesicular rims 60 80 nm these rims are characterized by a combination of three zones zone i occupies the outermost part of the surface modification which contains elements that are not included in the unchanged substrate minerals suggesting that this zone is composed of sputter deposits and or impact vapor deposits originating from the surrounding minerals redeposition rims are composed only of zone i and directly attaches to the unchanged minerals zone iii zone i of composite and composite vesicular rims often contains nanophase fe mg s the composite rims and the composite vesicular rims have a two layered structure a combination of zone i and zone ii below which zone iii exists zone ii is the partially amorphized zone zone ii of ferromagnesian silicates contains abundant nanophase fe radiation induced segregation and in situ reduction are the most plausible mechanisms to form nanophase fe in zone ii their lattice fringes indicate that they contain metallic iron which probably causes the reddening of the reflectance spectra of itokawa zone ii of the composite vesicular rims contains vesicles the vesicles in zone ii were probably formed by segregation of solar wind he implanted in this zone the textures strongly suggest that solar wind irradiation damage and implantation are the major causes of surface modification and space weathering on itokawa

the lunar far uv albedo indicator of hydration and weathering 1 we present an analysis of lunar reconnaissance orbiter lro lyman alpha mapping project lamp measurements of the dayside lunar surface at far ultraviolet wavelengths we use the strong 165 nm h2o absorption edge to look for diurnal variations in hydration we find that diurnal variations in spectral slope are indeed present they are superimposed on latitudinal and spatial variations related to composition and weathering we use two different spectral regions 164 173 nm and 175 190 nm to separate out these effects highlands and mare regions have distinct reflectance spectra with mare regions being spectrally bluer than highlands regions a consequence of the greater abundance of opaque minerals in mare regions bright ray terrains and areas known to be young such as giordano bruno crater are found to be relatively spectrally flat or red in the far uv this is consistent with a lack of space weathering which tends to make the far uv spectrum bluer due to the spectral behavior of nanophase iron large scale latitudinal variations in fuv slope are distinct and are likely due to a gradient in space weathering the diurnal variation in hydration is consistent with a solar wind origin and with loss of h2o at temperatures above 320 k far uv spectroscopy is thus shown to represent a viable method for mapping aqueous alteration even on the dayside of the moon and potentially elsewhere in the solar system

high spatial resolution studies of epithermal neutron emission from the lunar poles constraints on hydrogen mobility 1 the data from the collimated sensors of the lend instrument are shown to be of exceptionally high quality counting uncertainties are about 0 3 relative and are shown to be the only significant source of random error thus conclusions based on small differences in count rates are valid by comparison with the topography of shoemaker crater the spatial resolution of the instrument is shown to be consistent with the design value of 5 km for the radius of the circle over which half the counts from the lunar surface would be determined the observed epithermal neutron suppression factor due to the hydrogen deposit in shoemaker crater of 0 25 0 04 cps is consistent with the collimated field of view rate of 1 7 cps estimated by mitrofanov et al 2010a the statistical significance of the neutron suppressed regions nsrs relative to the larger surrounding polar region is demonstrated and it is shown that they are not closely related to the permanently shadowed regions there is a significant increase in h content in the polar regions independent of the h content of the nsrs the non nsr h content increases directly with latitude and the rate of increase is virtually identical at both poles there is little or no increase with latitude outside the polar region various mechanisms to explain this steep increase in the non nsr polar h with latitude are investigated and it is suggested that thermal volatilization is responsible for the increase because it is minimized at the low surface temperatures close to the poles

lateglacial and early holocene surface exposure ages of glacial boulders in the taiwanese high mountain range abstract glacial landforms and sediments mapped in three presently unglaciated mountain massifs the nanhuta shan the hsueh shan and the yushan support the concept of repeated multi stage glaciations in the taiwanese high mountain range during the late pleistocene new results from surface exposure dating using in situ produced cosmogenic 10 be measured in samples taken from erratic and moraine boulders in nanhuta shan at altitudes between 3100 and 3500 m are presented here the results confirm independent and previously reported optically stimulated luminescence osl ages and 10 be exposure ages from glacial deposits in the same area and suggest a lateglacial and early holocene glaciation the so called nanhuta glacier advance with two substages at about 12 15 ka and 9 5 ka bp the respective equilibrium line altitudes ela were calculated at 3340 m and 3440 m with corresponding ela depressions of 610 100 m and 510 100 m relative to the present day theoretical ela which is estimated to be at about 3950 100 m in taiwan large scale erosional landforms indicate a much wider glacier extent during an earlier stage which is not dated in nanhuta shan so far luminescence dating from near hsueh shan suggests an age of marine isotope stage mis 4 for this stage

interaction of mantle dregs with convection lateral heterogeneity at the core mantle boundary preliminary numerical models indicate that chemically denser material dregs at the base of the mantle would have substantial lateral variations in thickness induced by convection of the overlying mantle and might well form discontinuous aggregations below mantle upwellings a model with a density contrast of about 2 per cent and an initial uniform thickness of the denser layer of 100 km yields a discontinuous distribution with maximum thickness 230 km and bottom topography of several kilometers amplitude in reasonable accord with recent seismological observations of vertical and lateral structure heat flux out of the core is probably strongly modulated laterally by mantle convection while mantle dregs will complicate and possibly amplify this effect such modulation may be relevant to long term 10 7 10 8 year variations in the magnetic field

artemis observations of the solar wind proton scattering function from lunar crustal magnetic anomalies despite their small scales lunar crustal magnetic fields are routinely associated with observations of reflected and or backstreaming populations of solar wind protons solar wind proton reflection locally reduces the rate of space weathering of the lunar regolith depresses local sputtering rates of neutrals into the lunar exosphere and can trigger electromagnetic waves and small scale collisionless shocks in the near lunar space plasma environment thus knowledge of both the magnitude and scattering function of solar wind protons from magnetic anomalies is crucial in understanding a wide variety of planetary phenomena at the moon we have compiled 5 5 years of artemis acceleration reconnection turbulence and electrodynamics of the moon s interaction with the sun observations of reflected protons at the moon and used a liouville tracing method to ascertain each proton s reflection location and scattering angles we find that solar wind proton reflection is largely correlated with crustal magnetic field strength with anomalies such as south pole aitken basin spa mare marginis and gerasimovich reflecting on average 5 12 of the solar wind flux while the unmagnetized surface reflects between 0 1 and 1 in charged form we present the scattering function of solar wind protons off of the spa anomaly showing that the scattering transitions from isotropic at low solar zenith angles to strongly forward scattering at solar zenith angles near 90 such scattering is consistent with simulations that have suggested electrostatic fields as the primary mechanism for solar wind proton reflection from crustal magnetic anomalies

major lunar crustal terranes surface expressions and crust mantle origins in light of global remotely sensed data the igneous crust of the moon can no longer be viewed as a simple globally stratified cumulus structure composed of a flotation upper crust of anorthosite underlain by progressively more mafic rocks and a residual melt kreep sandwich horizon near the base of the lower crust instead global geochemical information derived from clementine multispectral data and lunar prospector gamma ray data reveals at least three distinct provinces whose geochemistry and petrologic history make them geologically unique 1 the procellarum kreep terrane pkt 2 the feldspathic high lands terrane fht and 3 the south pole aitken terrane spat the pkt is a mafic province coincident with the largely resurfaced area in the procellarum imbrium region whose petrogenesis relates to the early differentiation of the moon here some 40 of the th in the moon s crust is concentrated into a region that constitutes only about 10 of the crustal volume this concentration of th average 5 ppm and by implication the other heat producing elements u and k led to a fundamentally different thermal and igneous evolution within this region compared to other parts of the lunar crust lower crustal materials within the pkt likely interacted with underlying mantle materials to produce hybrid magmatism leading to the magnesian suite of lunar rocks and possibly kreep basalt although rare in the apollo sample collection widespread mare volcanic rocks having substantial th enrichment are indicated by the remote data and may reflect further interaction between enriched crustal residues and mantle sources the fht is characterized by a central anorthositic region that constitutes the remnant of an anorthositic craton resulting from early lunar differentiation basin impacts into this region do not excavate significantly more mafic material suggesting a thickness of tens of kilometers of anorthositic crust the feldspathic lunar meteorites may represent samples from the anorthositic central region of the fht ejecta from deep penetrating basin impacts outside of the central anorthositic region however indicate an increasingly mafic composition with depth the spat a mafic anomaly of great magnitude may include material of the upper mantle as well as lower crust thus it is designated a separate terrane whether the spa basin impact simply uncovered lower crust such as we infer for the fht remains to be determined

climate and geomorphology in the uppermost geomorphic belts of the central mountain range taiwan abstract the central mountain range of taiwan is in its lower parts exposed to strong denudation by mass movements caused by extreme rainfalls and active tectonics even though the uppermost regions of the mountains are also influenced by earthquakes and typhoon rains present geomorphic activity is low investigations based on field work and air photo study in nanhuta shan 3742 m and yushan 3952 m and the analysis of climate data indicate the presence of a periglacial belt with a lower limit at 3600 3700 m the upper limit of the periglacial belt in taiwan is not met ground temperature measurements in nanhuta shan show that freeze thaw activity at 3560 m during the winter is restricted to the top few centimetres of the ground and the maximum frost depth is 25 cm the only indicator landforms within the periglacial belt are smooth slopes the high relief energy and a lack of fine material account for the absence of other periglacial landforms relict solifluction terraces debris cones and slope failures found between 3400 and 3600 m in nanhuta shan are strong evidence for a period of increased slope activity during the holocene which in two cases were dated by osl to approx 3 ka at least one solifluction unit developed during a cooler phase between 3 ka and today

irradiation of olivine by 4 kev he simulation of space weathering by the solar wind 1 we have studied the effects of 4 kev he ion irradiation on olivine while measuring in situ changes in the near infrared nir reflectance and in the chemical composition of the surface the observed changes in reflectance are reddening and the attenuation of the fe 3d absorption bands in the nir spectral reddening of irradiated olivine powder 45 m correlates with the amount of metallic iron formed by ion impact consistent with the idea that space weathering effects in the reflectance of olivine bearing s type asteroids are due to the formation of metallic iron the metallization rate of the powder is about half that of a sectioned rock of olivine which we propose is a consequence of redeposition of sputtered material the nir spectral changes observed in ion irradiation experiments are similar to those observed in our previous experiments on vapor redeposition indicating that different space weathering mechanisms can lead to similar final effects on reflectance finally we estimate that at 1 au the spectral reddening caused by the solar wind saturates approximately 2 orders of magnitude faster than comparable reddening caused by micrometeorite impacts

dynamical effects on the core mantle boundary from depth dependent thermodynamical properties of the lower mantle a common assumption in modelling dynamical processes in the lower mantle is that both the thermal expansivity and thermal conductivity are reasonably constant recent work from seismic equation of state leads to substantially higher values for the thermal conductivity and much lower thermal expansivity values in the deep mantle the dynamical consequences of incorporating depth dependent thermodynamic properties on the thermal mechanical state of the lower mantle are examined with the spherical shell mean field equations we find that the thermal structure of the seismically resolved anomalous zone at the base of the mantle d is strongly influenced by these variable properties and in particular that the convective distortion of the core mantle boundary cmb is reduced with the decreasing thermal expansivity such a reduction of the dynamically induced topography from pure thermal convection would suggest that some other dynamical mechanism must be operating at the cmb

hydroxyl oh production on airless planetary bodies evidence from h d ion beam experiments abstract the hypothesis that bombardment of lunar soil with solar wind protons might form hydroxyl oh and perhaps hoh has been tested by experiments with apollo 16 highlands and apollo 17 mare soils pre dried soils 500 c were bombarded with 1 1 kev protons and deuterons and provide unambiguous evidence for the formation of oh or od in both samples this hypothesis further predicts the formation of hydroxyl oh on other airless planetary asteroidal bodies with a sufficient solar wind flux deuteron implantation of unaltered lunar soils and a heat treated plagioclase specimen cause simultaneous oh depletion and od formation ion bombardment of lunar soils simulates the dynamic process of hydroxyl formation and may also deplete intrinsic oh thereby effectively contributing to the day night diurnal variability of oh reported by sunshine et al 2009 our results emphasize the need to use lunar soils with space weathered exteriors in laboratory simulations of the solar wind infrared spectra of hydrogen ion beam implanted soils are similar to spectra obtained at relab brown univ and to those observed by remote sensing confirming the solar wind hypothesis

thrust related river terrace development in relation to the 1999 chi chi earthquake rupture western foothills central taiwan abstract the 21 september 1999 earthquake mw 7 6 produced a surface rupture that extended for 100 km in a general north south direction in front of the western foothills central taiwan the study area located in a segment of the fold thrust belt of central taiwan provides an important natural laboratory to study the relationship between active thrust deformation and fluvial terrace development we recognize from west to east three subparallel thrusts the sanyi houli and shihkang faults in the northern part of the earthquake disaster area the 1999 earthquake rupture occurred only along the shihkang fault whereas the other two faults were inactive along the tachia river in the hanging wall of the shihkang fault eight well developed terrace levels are observed and can be subdivided into lateritic lt5 lt1 and non lateritic terraces ft3 ft1 five levels of lateritic terrace lt5 lt1 are located in the hanging wall of the houli fault and a lateritic terrace lt5 is present in the hanging wall of the sanyi fault stratigraphic and elevation correlations between these well developed fluvial terraces in relationship to nearby geologic structures show that the sanyi fault is the oldest structure lateritic terraces of at least 10 000 yr bp for example overlie the sanyi fault but correlative terraces associated with the houli fault are offset these types of terrace correlations allow us to define the progressive development of the thrust system within the western foothills

understanding the lunar surface and space moon interactions the surface of the moon is a critical boundary that shapes our understanding of the moon as a whole all geologic mapping and remote sensing techniques utilize only the outermost portion of the moon before leaving the moon for study in our laboratories all lunar samples that have been studied existed at or very near the surface with the exception of the deeply probing geophysical techniques our understanding of the interior of the moon is derived from surficial but not superficial information coupled with boundary of the lunar crust it is the lower boundary layer of the tenuous lunar atmosphere and constitutes both a source and a sink for atmospheric gases the surface is also where the moon interacts with the space environment causing changes in the physical nature of lunar materials and provides a laboratory for the study of processes that occur on all airless bodies the data obtained remotely by the galileo clementine and lunar prospector missions as well as data derived from lunar meteorites have resulted in major changes to our understanding of global distributions of chemistry and rocks this chapter summarizes the current understanding of this critical interface the surface of the moon in its role as the lower boundary of the lunar atmosphere the upper boundary of the crust and the window through which we view through remote sensing the composition of the crust and the history of the moon in this post lunar prospector time the view of the moon has changed lending new perspectives to lunar samples and lunar processes but the new view will likely remain in flux as we continue to digest the results from these recent space missions and move forward to a new era of lunar exploration despite the freshness of our perspective this is an important moment to capture

late quaternary river terraces in the central mountain range of taiwan a study of cover sediments across a terrace section along the tachia river abstract the existence of fluvial terraces in the high mountains of taiwan has been known for a long time already but these terraces have not yet been studied in detail this paper studies cover sediments across a terrace section in the central mountain range located at the midstream reaches of the tachia river at an elevation of 1430 m asl sediments were dated by means of optically stimulated luminescence and radiocarbon dating yielding robust ages between 54 8 7 0 ka and 0 42 0 09 cal ka bp these dates are in good agreement with ages known for the laterite terraces lt in the mountain foreland deeply weathered reddish soils comparable to those in the mountain forelands are absent hence in stratigraphic terms the terraces in the high mountains cannot be correlated with those in the mountain foreland cover sediments comprise eolian sand and silt and various colluvial layers eolian sediments provide paleoenvironmental evidence of a relatively dry phase in early mis 3 that coincides with the maximum extent of the glaciations in the hsueh shan mountain area widespread colluvial sediments indicate a high frequency of mass movements around 38 5 ka a period of time known to correlate with dominantly wet conditions in the last 1000 years wildfire appears as a possible trigger of mass movements the geochronological data indicate a local bedrock strath incision rate of 0 8 0 1 mm y 1 a value that appears to be in agreement with the local decadal scale erosion rate

the relation between climate and river processes landforms and deposits during the quaternary abstract the extent to which river processes and morphology are dependent on climate is an old question when looking at large time scales climatic cyclicity seems to coincide with alternating events in fluvial development however the shorter the time scales at which fluvial development is considered the more it is difficult to find a close correspondence with climate evolution ultimately it appears that the response time of river processes to climatic change may restrict the sensitivity of the fluvial systems to adapt to short climatic oscillations the impact of climate on fluvial systems is largely transferred to these systems by the climate determined soil cohesion and peak discharges the latter factors are especially related to vegetation cover and permafrost conditions finally a number of basin characteristics are discussed that demonstrate that fluvial systems are not completely controlled by climate

sources and physical processes responsible for oh h2o in the lunar soil as revealed by the moon mineralogy mapper m3 1 analysis of two absorption features near 3 m in the lunar reflectance spectrum observed by the orbiting m3 spectrometer and interpreted as being due to oh and h2o is presented and the results are used to discuss the processes producing these molecules this analysis focuses on the dependence of the absorptions on lunar physical properties including composition illumination latitude and temperature solar wind proton induced hydroxylation is proposed as the creation process and its products could be a source for other reported types of hydrogen rich material and water the irregular and damaged fine grained lunar soil seems especially adapted for trapping solar wind protons and forming oh owing to abundant dangling oxygen bonds the m3 data reveal that the strengths of the two absorptions are correlated and widespread and both are correlated with lunar composition but in different ways feldspathic material seems richer in oh these results seem to rule out water from the lunar interior and cometary infall as major sources there appear to be correlations of apparent band strengths with time of day and lighting conditions however thermal emission from the moon reduces the apparent strengths of the m3 absorptions and its removal is not yet completely successful further many of the lunar physical properties are themselves intercorrelated and so separating these dependencies on the absorptions is difficult due to the incomplete m3 data set this process should also operate on other airless silicate surfaces such as mercury and vesta which will be visited by the dawn spacecraft in mid 2011

the distribution of apparent dose as determined by optically stimulated luminescence in small aliquots of fluvial quartz implications for dating young sediments abstract we noted recently murray et al 1995 that quartz samples taken from in channel fluvial deposits have apparent doses ranging over several orders of magnitude we suggested that these dose distributions are best explained by a mixture of a small number of poorly bleached grains and a larger number of well bleached grains in this paper we examine the distribution of apparent dose in small aliquots each composed of 2000 grains of different particle size fractions 63 90 m 90 125 m 125 180 m 180 212 m 212 250 m diameter from two samples collected from the murrumbidgee river new south wales australia the samples are of known burial age the first being 70 years old and the second being its modern equivalent 0 2 gy the difference in the lowest apparent dose in the two samples is considered to be the result of their different burial times we suggest a method for dating recently deposited

sedimentary features and ages of fluvial terraces and their implications for geomorphic evolution of the taomi river catchment a case study in the puli basin central taiwan abstract fluvial terraces play an important role for research on previous geomorphic processes as their sediments can record various sedimentation stages in the mountains of central taiwan however the formation time of sediments in the puli basin is still unclear in this study we investigate the fluvial sediments of a fluvial terrace in the taomi river catchment in the puli basin in terms of sedimentology and geochronology and consider their implications for geomorphic evolution in the puli basin optically stimulated luminescence osl dating shows that fine grained and homogeneous sediment in the studied fluvial terrace was deposited at 12 3 1 7 ka and 12 0 2 1 ka these dating results are consistent with the age of 14 5 0 4 ka cal b p from the radiocarbon dating of a charcoal fragment a third osl age of 8 7 1 4 ka suggests that the overlying fluvial gravels started to form in the early holocene based on the dating results and the sedimentological and geomorphic characteristics of the fluvial terrace under study a preliminary model of the geomorphic evolution of the taomi river catchment is proposed i the fine grained sediment had been deposited at the end of the late pleistocene ii in the early holocene fluvial gravel deposits were formed probably caused by a climatic shift from dry to wet iii huge scaled incision of the taomi river took place possibly associated with rapid holocene river incision iv incision stopped and the studied fluvial terrace was formed later young fluvial terraces as derived from the analysis of a high resolution dtm related to episodic incision of the river were formed the modern river channel is 20 m below the studied outcrop

fluxes of fast and epithermal neutrons from lunar prospector evidence for water ice at the lunar poles maps of epithermal and fast neutron fluxes measured by lunar prospector were used to search for deposits enriched in hydrogen at both lunar poles depressions in epithermal fluxes were observed close to permanently shaded areas at both poles the peak depression at the north pole is 4 6 percent below the average epithermal flux intensity at lower latitudes and that at the south pole is 3 0 percent below the low latitude average no measurable depression in fast neutrons is seen at either pole these data are consistent with deposits of hydrogen in the form of water ice that are covered by as much as 40 centimeters of desiccated regolith within permanently shaded craters near both poles

early holocene catastrophic mass wasting event and fan delta development on the hua tung coast eastern taiwan abstract landslides and debris flows rarely occurred during historical times in the tectonically active coastal range of eastern taiwan this topographic stability however contrasts greatly with the widespread existence of terraced alluvial fans and fan deltas on the hua tung coast which fringes the range this study focuses on the two largest fan terrace systems on the hua tung coast both of which consist of alluvial fans plane view areas up to 8 km 2 larger than their contributing catchments stratigraphic data show that both systems were in sandy wave dominated settings during de glacial times the systems were then disturbed by a catastrophic landslide debris flow event or events which brought enormous amounts of gravel facies gm into the systems deforming previously deposited marine sands facies sm and shallowing the seafloor the combined gm sm complex yields multiple radiocarbon dates ranging from 11 3 to 8 3 ka cal bp with a cluster around 8 6 ka cal bp this mass wasting event has been unique since the emergence of its contributing catchment 0 2 0 3 ma ago the low frequency of such an event could reflect the great resistance of rock mass in the source areas to weathering and erosion the common blockage of valley floors by giant boulder piles which limits channel incision and sediment transport could also increase the apparent stability of the mountain the trigger of landslides in the coastal range has been linked to large earthquakes additionally we propose that the great magnitude and duration of the observed early holocene event were caused by the contemporaneous prolonged rainfall and or high frequency of typhoons associated with the east asian summer monsoon maximum

evidence for water ice near the lunar poles improved versions of lunar prospector thermal and epithermal neutron data were studied to help discriminate between potential delivery and retention mechanisms for hydrogen on the moon improved spatial resolution at both poles shows that the largest concentrations of hydrogen overlay regions in permanent shade in the north these regions consist of a heavily cratered terrain containing many small less than 10 km diameter isolated craters these border circular areas of hydrogen abundance h that is only modestly enhanced above the average equatorial value but that falls within large flat bottomed and sunlit polar craters near the south pole h is enhanced within several 30 km scale craters that are in permanent shade but is only modestly enhanced within their sunlit neighbors we show that delivery by the solar wind cannot account for these observations because the diffusivity of hydrogen at the temperatures within both sunlit and permanently shaded craters near both poles is sufficiently low that a solar wind origin cannot explain their differences we conclude that a significant portion of the enhanced hydrogen near both poles is most likely in the form of water molecules

space weathering on airless bodies space weathering refers to alteration that occurs in the space environment with time lunar samples and to some extent meteorites have provided a benchmark for understanding the processes and products of space weathering lunar soils are derived principally from local materials but have accumulated a range of optically active opaque particles oaopq that include nanophase metallic iron on in rims formed on individual grains imparting a red slope to visible and near infrared reflectance and larger iron particles which darken across all wavelengths such as are often found within the interior of recycled grains space weathering of other anhydrous silicate bodies such as mercury and some asteroids produce different forms and relative abundance of oaopq particles depending on the particular environment if the development of oaopq particles is minimized such as at vesta contamination by exogenic material and regolith mixing become the dominant space weathering processes volatile rich bodies and those composed of abundant hydrous minerals dwarf planet ceres many dark asteroids outer solar system satellites are affected by space weathering processes differently than the silicate bodies of the inner solar system however the space weathering products of these bodies are currently poorly understood and the physics and chemistry of space weathering processes in different environments are areas of active research

modes of covariability between sea surface temperature and wind stress intraseasonal anomalies along the coast of peru from satellite observations 2000 2008 1 the tropical rainfall measuring mission microwave imager sea surface temperature sst and quikscat wind stress satellite data are used to investigate the intraseasonal upwelling variability along the coat of peru over the period 2000 2008 two regions of peak variance correspond to the central peru region pisco region 15 s and the northern peru region piura region 5 s a covariance analysis reveals a significant coherency between winds and sst anomalies off pisco consistent with ekman pumping and transport dynamics the upwelling cell consists in a meridionally extended fringe of colder warmer water extending as far as 250 km from the coast at 15 s in the piura region the intraseasonal covariability pattern is represented by two modes one relevant to the direct ekman dynamics and the other one associated with the remote forcing of intraseasonal oceanic kelvin wave two regimes of variability are evidenced a low period regime 10 25 days is the signature of ekman transport pumping dynamics and is remotely forced by the migratory atmospheric disturbances across the southeastern pacific anticyclone a high period regime 35 60 day band is associated with the combined forcing of oceanic equatorial kelvin waves and migratory atmospheric disturbances in the midlatitudes in particular the modes of covariability exhibit a prominent 50 day period energy peak it is shown that this period arises from the impact of the first two baroclinic modes kelvin wave with the second baroclinic mode kelvin wave being more influential on the piura region

direct measurement of hydroxyl in the lunar regolith and the origin of lunar surface water remote sensing discoveries of hydroxyl and water on the lunar surface have reshaped our view of the distribution of water and related compounds on airless bodies such as the moon the origin of this surface water is unclear but it has been suggested that hydroxyl in the lunar regolith can result from the implantation of hydrogen ions by the solar wind here we present fourier transform infrared spectroscopy and secondary ion mass spectrometry analyses of apollo samples that reveal the presence of significant amounts of hydroxyl in glasses formed in the lunar regolith by micrometeorite impacts hydrogen isotope compositions of these glasses suggest that some of the observed hydroxyl is derived from solar wind sources our findings imply that ice in polar cold traps could contain hydrogen atoms ultimately derived from the solar wind as predicted by early theoretical models of water stability on the lunar surface we suggest that a similar mechanism may contribute to hydroxyl on the surfaces of other airless terrestrial bodies where the solar wind directly interacts with the surface such as mercury and the asteroid 4 vesta

laboratory spectroscopic detection of hydration in pristine lunar regolith abstract reflectance spectroscopy of apollo lunar soil samples curated in an air and water free sealed environment since recovery and return to earth has been carried out under water oxygen co 2 and organic controlled conditions spectra of these pristine samples contain features near 3 m wavelength similar to those observed from the lunar surface by the chandrayaan 1 moon mineralogy mapper m 3 cassini visual and infrared mapping spectrometer vims and deep impact extrasolar planet observation and deep impact extended investigation epoxi high resolution instrument hri instruments spectral feature characteristics and inferred oh h 2 o concentrations are within the range of those observed by spacecraft instruments these findings confirm that the 3 m feature from the lunar surface results from the presence of hydration in the form of bound oh and h 2 o implantation of solar wind h appears to be the most plausible formation mechanism for most of the observed lunar oh and h 2 o

deformation of the core mantle boundary induced by spherical shell compressible convection we derive the single mode mean field equations for spherical shell convection with variable viscosity and compressibility included core mantle boundary cmb topography produced by whole mantle convection is computed for various rheologies and different thermal boundary conditions at cmb results for long wavelength undulations show the extreme sensitivity of these signatures to rheological and equation of state parameters in order to obtain excess ellipticity of about 1 km the activation energy and volume in the lower mantle should be low and the temperatures at cmb around 4 500 k in accord with recent experimental findings

1999 chi chi earthquake a case study on the role of thrust ramp structures for generating earthquakes the 21 september 1999 chi chi earthquake m w 7 6 occurred on east dipping shallow thrust faults that produced a high relief surface rupture extraordinary surface breaks appeared that could be clearly traced for about 100 km across many counties these thrust faults the chelungpu and shihkang are part of an active fold and thrust belt related to ongoing recent arc continent collision measurement of slip vectors along the earthquake rupture indicates that the orientation of the maximum shear stress changed from a westward direction n70 90 w on the chelungpu fault to a northwestward direction n30 40 w on the shihkang fault the stress field underwent a clockwise rotation of about 40 during the chi chi earthquake near rupture vertical displacements in the hanging wall of the shihkang fault have more cumulative displacement than on the chelungpu fault which is consistent with global positioning system gps measurements maximum vertical offset on the rupture was found to be about 10 m by the surficial rupture and gps measurements in addition analysis of crustal deformation by gps measurements on the hanging wall defines a coseismic uplift related to a fault ramp structure our synthesis of geological and geodetic analyses shows the importance of ramp structures associated with thrust faults for generating large earthquakes and provides a general framework for understanding earthquake in fold and thrust belts large surficial coseismic uplift and strong asperities appear to be a function of fault ramp geometry our analysis also indicates that in general ramp structures in fold and thrust belts may have a high potential in generating large earthquakes manuscript received 14 november 2000

dynamical influences from thermal chemical instabilities at the core mantle boundary two dimensional time dependent calculations show that the thermal and flow structures can be influenced by the lower mantle thermal chemical instabilities the style of the core mantle boundary cmb deformation in thermal chemical convection is different from that obtained in thermal convection the amplitude of cmb hills is reduced greatly from the depth dependence of thermal expansivity found in recent high pressure experiments

geomorphic evidence for an active pop up zone associated with the chelungpu fault in central taiwan abstract the destructive chi chi earthquake mw 7 6 ml 7 3 occurred in central taiwan on september 21 1999 the surface ruptures extend more than 100 km mainly along the chelungpu fault the northerly striking ruptures however branch and turn northeast from shihgang to neiwan in this vicinity a group of unpaired and polycyclic terraces along the tachia river known as hsinshe river terraces is situated on the hanging wall of the chelungpu fault many of the terraces were tilted and the younger ones and the river beds popped up during the chi chi earthquake the geomorphic evidence suggests that the terraces in the western group have been continually deformed by a pop up structure with a hinge coincident with that of the 1999 pop up deformation it suggests that the pop up structure of the chi chi earthquake has developed since the late pleistocene and has migrated northward along with tectonic activity of the chelungpu fault however the early deformation of this pop up structure shows a kink fold style as this structure propagates northward the tachia river has been diverted around its plunging nose four cycles of tectonic uplift channel migration point bar formation have been recognized in the hsinshe river terraces and serve as a model for river response to growing tectonics furthermore this study tentatively estimates the rate of 4 75 0 62 m ka for tectonic uplift in the pop up zone and 2 73 0 35 m ka for the regional rate of uplift because the pop up structure is a secondary structure associated with the main thrust the chelungpu fault the rates estimated in this study give the lower bound of the vertical slip rate in this region

the structure of the core mantle boundary from diffracted waves diffracted p and s waves pd sd traveling around the core mantle boundary cmb of the earth give us information about the velocity structure and therefore the thermochemistry of d the base of the earth s mantle by examining pd and sdarrivals we determined the apparent ray parameter for different regions at the base of the mantle by comparing the data slownesses to those found from reflectivity synthetic seismograms we were able to quantify d average velocities using these averaged velocities with a thermochemical modeling of lower mantle minerals using a birch mumaghan equation of state we have been able to make chemical and physical inferences as to the causes of lateral variations at the cmb examinations found significant lateral heterogeneity at the base of the mantle amounting to 4 for both p and s velocities these velocities did not always vary in parallel and the poisson ratio varied regionally by almost 6 the most unusual region of the cmb found was under indonesia where velocities 3 slower than the preliminary reference earth models were found adjacent to a region of faster than average velocities these regions currently correspond to areas of core up welling and down welling respectively found by voorhies 1986 which if mostly held in place by core mantle coupling might cause a flux of heat and iron into the mantle making the anomaly both thermally and chemically derived at the cmb under the northern pacific rim the fastest shear velocities were found but the same region yielded slower than average p velocities while the presence of fast shear velocities here would support the idea that we are seeing the cold dregs of mantle convection perhaps continuing down from the north pacific subduction zones the presence of slow p velocities suggests additional complications our thermochemical modeling suggests that the d poisson ratio is very sensitive to variations in the silicate oxide ratio and that a decrease in the amount of perovskite relative to magnesiowustite may play an important role in this region

widespread distribution of oh h 2 o on the lunar surface inferred from spectral data remote sensing data from lunar orbiters have revealed spectral features consistent with the presence of oh or h2o on the lunar surface analyses of data from the moon mineralogy mapper spectrometer onboard the chandryaan 1 spacecraft have suggested that oh h2o is recycled on diurnal timescales and persists only at high latitudes however the spatial distribution and temporal variability of the oh h2o as well as its source remain uncertain here we incorporate a physics based thermal correction into analysis of reflectance spectra from the moon mineralogy mapper and find that prominent absorption features consistent with oh h2o can be present at all latitudes local times and surface types examined this suggests the widespread presence of oh h2o on the lunar surface without significant diurnal migration we suggest that the spectra are consistent with the production of oh in space weathered materials by the solar wind implantation of h and formation of oh at crystal defect sites as opposed to h2o sourced from the lunar interior regardless of the specific composition or formation mechanism we conclude that oh h2o can be present on the moon under thermal conditions more wide ranging than previously recognized

space weathering from mercury to the asteroid belt the variety of evidence bearing on the nature of space weathering is reviewed the effects of space weathering include spectral darkening reddening and subdued absorption bands and the distinctive magnetic electron spin resonance caused by single domain metallic iron particles ever since the apollo missions two paradigms have dominated the thinking of the planetary science community concerning space weathering 1 the optical effects are caused by impact vitrified glass in agglutinates and 2 the submicroscopic metallic iron results from the reduction of ferrous iron by the impact melting of minerals whose surfaces have been saturated with hydrogen from the solar wind however studies carried out since the apollo program showed that both of these paradigms are invalid a hypothesis first suggested by the author and his colleagues 26 years ago but not generally accepted at that time now appears to be essentially correct both the optical and magnetic effects are caused by metallic iron particles smaller than the wavelength in ubiquitous vapor deposited coatings on soil particle surfaces and inside agglutinates the vapor is generated by both solar wind sputtering and micrometeorite impact vaporization and injected preferentially downward into the porous regolith the iron is reduced by a physical process the selective loss of oxygen that occurs during deposition of the vapor and does not require heating melting or a reducing environment a mathematical theory that describes the optical effects of the submicroscopic iron quantitatively is derived and applied to the regoliths of the moon mercury and an s asteroid

recursive plasma wake formation on the moon and its effect on polar volatiles abstract solar wind plasma flows almost horizontally in near terminator regions of the moon one question is how does this plasma flow around topographic features like near terminator mountains and polar craters we present kinetic simulations of plasma inflow into a complicated polar crater having a second child crater within the parent crater i e a crater in a crater model we find that the effect on the inflowing ions of this second child feature is a function of its position downstream relative to the primary crater wall close to the wall where the solar wind is occulted there is little ion inflow and thus not a significant perturbation from the child obstruction however beyond about two crater wall heights downstream there is substantial ion flow and the child obstruction will create a second ambipolar wake region similar to that created by the first obstruction we also present a general analytical formalism that explains the most critical properties of the inflow perturbations finally we consider the effect of the ion inflow into polar craters with 1 water frost mixed within the top micron layers of the regolith we find that in order to maintain equilibrium a persistent frost most likely has to be maintained by a dynamic water source of 10 9 molecules m 2 s 1 in polar craters to offset solar wind ion inflow sputtering losses

late pleistocene to holocene alluvial tableland formation in an intra mountainous basin in a tectonically active mountain belt a case study in the puli basin central taiwan abstract the morphology in taiwan is a product of high tectonic activity at the convergent margin and east asian monsoon climate tablelands are prominent geomorphic features in the puli basin in central taiwan these tablelands provide an archive to understand links between past climatic evolution and tectonic events resulting in the formation of the present day landforms to establish a geochronological framework for the alluvium underlying the tablelands in the puli basin optically stimulated luminescence dating was applied to obtain burial ages the numerical data indicate an accumulation phase of alluvial fans in the late pleistocene to early holocene transition the study area in the taomi river catchment an obvious longer precursor of the taomi river originating from west of the yuchih basin transported the sediments forming the present day southern tablelands during the pleistocene holocene transition the climate changed to wetter and warmer conditions so that slope processes might have changed and an increasing transport in the fluvial system was stimulated fluvial and fan terraces in other river catchments in taiwan also indicate a period of increased fluvial transport and deposition a geomorphic evolution model in the puli basin is reconstructed on the basis of the chronological framework and of sedimentological features fluvial processes controlled by climatic change and accompanied by tectonic activities have created the diverse topography in the puli basin

latitudinal variation in spectral properties of the lunar maria and implications for space weathering abstract space weathering alters the optical properties of exposed surfaces over time complicating the interpretation of spectroscopic observations of airless bodies like asteroids mercury and the moon solar wind and micrometeoroids are likely the dominant agents of space weathering but their relative contributions are not yet well understood based primarily on clementine mosaics we report a previously unrecognized systematic latitudinal variation in the near infrared spectral properties of the lunar maria and show that the characteristics of this latitudinal trend match those observed at lunar swirls where magnetic fields alter local solar wind flux without affecting the flux of micrometeoroids we show that the observed latitudinal color variations are not artifacts of phase angle effects and cannot be accounted for by compositional variation alone we propose that reduced solar wind flux which should occur both at swirls and toward higher latitudes is the common mechanism behind these color variations this model helps us quantify the distinct effects of solar wind and micrometeoroid weathering and could aid in interpreting the spectra of airless bodies throughout the solar system

chlorine distribution and its isotopic composition in rusty rock 66095 implications for volatile element enrichments of rusty rock and lunar soils origin of rusty alteration and volatile element behavior on the moon abstract an interesting characteristic of the pyroclastic glass bead deposits select impact produced lithologies such as the rusty rock 66095 and unique lunar soils from the apollo 16 landing site is their unusual enrichments in 204 pb cd bi br i ge sb tl zn and cl which indicates that portions of these sample contain a substantial volatile component sample 66095 a fine grained subophitic to ophitic polymict melt breccia also hosts a pervasive low temperature volatile rich oxyhydrated mineral assemblage the volatile element enrichments in these assorted lunar lithologies have been attributed to a variety of extra lunar and lunar processes whereas the oxyhydration in 66095 has long been thought to represent either terrestrial alteration of lunar chlorides and fe ni metal to feo oh cl or indigenous lunar processes in 66095 cl is accommodated in feo oh cl phosphates and chlorides and is heterogeneously distributed the low temperature alteration occurs as rims around fe ni metal and sulfide grains and as dispersed grains in the adjacent matrix micro raman and transmission electron microscope tem imaging indicate that akaganeite feo oh cl is the dominant feo oh polymorph and is intergrown with goethite feo oh and hematite fe 2 o 3 tem observations indicate a well defined nanometer scale stratigraphy to the alteration for example kamacite body centered cubic face centered cubic fcc fe ni alloy lawrencite fecl 2 akaganeite the lunar lawrencite fe ni cl 2 in 66095 does not react directly to akaganeite on earth rather lawrencite exposed to terrestrial conditions reacts to form an amorphous fe and cl bearing phase nano crystalline goethite and hematite the morphology of these terrestrial alteration products is significantly different than that of the akaganeite occurring in 66095 the chlorine isotopic compositions of these volatile rich samples are enriched in heavy cl for 66095 the 37 cl ranges from 14 0 to 15 6 whereas the 37 cl for the volatile rich a16 soils ranges from 5 6 to 15 7 based on these data it appears likely that the volatile element enrichments and the cl isotopic fractionation observed in 66095 and the apollo 16 soils did not result from extra lunar additions but are most likely indigenous to the moon lawrencite was deposited on mineral surfaces at approximately 650 c to 570 c from a metal chloride bearing h poor gas phase this gas phase was also responsible for the transport of other metals e g zn cu pb fe the fractionation of cl isotopes in the rusty rock can be attributed to fumarole processes in a low h system the origin and formation of the akaganeite is more enigmatic the cl isotopes are consistent with it replacing lawrencite however numerous nanometer scale observations are not consistent with a terrestrial origin and indicate multiple episodes of oxyhydration

pollen stratigraphy vegetation and environment of the last glacial and holocene a record from toushe basin central taiwan abstract the pollen record from the toushe basin 23 49 n 120 53 e 650 m above sea level a peat bog of central taiwan displays a continuous vegetation history of the past 96 000 yr bp of monsoon asia instead of today s closed subtropical evergreen broadleaved forest dominated by machilus castanopsis surrounding the basin temperate deciduous forest predominated during most of the last glacial in early mis 4 alnus reaches the highest value of the whole sequence 60 70 representing temperate deciduous forest and relatively cold and arid conditions following this stadial alnus and herbs mainly cyperaceae dominated alternately with a minor increase of castanopsis peaks of monolete spores between cal 42 2 and 37 0 kyr bp kyr bp represent calibrated years indicate episodic wet conditions the later glacial especially between 23 2 and 18 7 kyr bp shows a high percentage of gramineae indicating dry and possibly sometimes cold conditions the late glacial shows a remarkable increase of warm temperate to temperate forest elements such as ilex cyclobalanopsis and symplocos at about 15 1 kyr bp a peak of monolete spores indicates wet warm conditions a subsequent sharp increase of salix and then gramineae between 13 0 and 11 6 kyr bp corresponds to the younger dryas a warming event at 11 5 kyr bp is also evident the holocene is characterized by warm wet conditions of the overwhelmingly abundant monolete spores since 10 7 kyr bp and the prominent increase of castanopsis

using subdivision surfaces and adaptive surface simplification algorithms for modeling chemical heterogeneities in geophysical flows 1 we present a new method for investigating the transport of an active chemical component in a convective flow we apply a three dimensional front tracking method using a triangular mesh for the refinement of the mesh we use subdivision surfaces which have been developed over the last decade primarily in the field of computer graphics we present two different subdivision schemes and discuss their applicability to problems related to fluid dynamics for adaptive refinement we propose a weight function based on the length of triangle edge and the sum of the angles of the triangle formed with neighboring triangles in order to remove excess triangles we apply an adaptive surface simplification method based on quadric error metrics we test these schemes by advecting a blob of passive material in a steady state flow in which the total volume is well preserved over a long time since for time dependent flows the number of triangles may increase exponentially in time we propose the use of a subdivision scheme with diffusive properties in order to remove the small scale features of the chemical field by doing so we are able to follow the evolution of a heavy chemical component in a vigorously convecting field this calculation is aimed at the fate of a heavy layer at the earth s core mantle boundary since the viscosity variation with temperature is of key importance we also present a calculation with a strongly temperature dependent viscosity

linking taiwan s subcritical hsuehshan range topography and foreland basin architecture of 10 1 kilometers and 10 4 10 5 years causal links between the structural and synorogenic stratigraphic architecture of the foreland basin and coincidence of the puli topographic embayment provide a valuable case study of the effects of changing boundary conditions e g variable erodibility or strength of rocks along strike controlling the evolution of critically tapered thin skinned orogens deeper incision of river networks into a thicker sequence of unconsolidated synorogenic sediments in the central western foreland may affect the onset of a topographically subcritical state

plume formation in the d double prime layer and the roughness of the core mantle boundary numerical simulations of the formation of thermal plumes in the d layer at the base of the earth s mantle show that plumes are initiated by coalescence of small scale convective instabilities within the low viscosity region immediately above the core mantle boundary cmb these instabilities support topographic roughness on the cmb having horizontal scales of 20 50 km and provide a source for scattered p waves seen as precursors to the phases pkikp and pkkp the calculated structure of fully developed plumes emerging from d consists of 5 50 cm yr 1 flow confined to 50 100 km thick vertical conduits with strongly temperature dependent viscosity plumes exhibit time dependent behaviour including upward propagating solitary conduit waves which may contribute to episodicity in hotspot volcanism

the nature and origin of rims on lunar soil grains abstract space weathering processes that operate in the lunar regolith modify the surfaces of lunar soil grains transmission electron microscope analysis of the lunar soil grains from the fine size fraction of several lunar soils show that most grains are surrounded by thin 60 200 nm thick rims the microstructure and chemical compositions of the rims can be used to classify rims into four broad categories amorphous inclusion rich multiple and vesicular amorphous rims are noncrystalline generally lack crystalline inclusions show evidence for preferential sputtering of cations and are produced largely by solar wind irradiation damage inclusion rich rims contain abundant nanometer sized grains of fe metal as randomly dispersed inclusions or as distinct layers embedded in an amorphous silica rich matrix inclusion rich rims are compositionally distinct from their host grains and typically contain accumulations of elements that are not indigenous to the host inclusion rich rims are formed largely by the deposition of impact generated vapors with a contribution from the deposition of sputtered ions a continuum in the chemical and microstructural properties exists between typical amorphous rims and typical inclusion rich rims multiple rims consist of a distinct radiation damaged layer up to 50 nm thick that is overlain by vapor deposited material of comparable thickness vesicular rims are compositionally similar to their hosts and are characterized by an abundance of small the formation of rims on lunar soils is complex and involves several processes whose effects may be superimposed from this study it is shown that one process does not dominate and that the relative importance of vapor deposition is comparable to radiation damage in the formation of rims on lunar silicate grains the presence of rims on lunar soil grains particularly those with nanometer sized fe metal inclusions may have a major influence on the optical and magnetic properties of lunar soils

detection of structurally bound hydroxyl in fluorapatite from apollo mare basalt 15058 128 using tof sims fluorapatite grains from apollo 15 mare basalt 15058 128 were analyzed by raman spectroscopy raman spectral imaging time of flight secondary ion mass spectrometry tof sims field emission scanning electron microscopy fe sem and electron probe microanalysis epma in an attempt to detect structurally bound oh in the fluorapatite although oh could not be definitively detected by raman spectroscopy because of ree induced photoluminescence hydroxyl was detected in the fluorapatite by tof sims the tof sims technique is qualitative but capable of detecting the presence of hydroxyl even at trace levels electron microprobe data indicate that on average f and cl f cl fill the monovalent anion site in these fluorapatite grains within the uncertainties of the analyses about 0 07 0 01 atoms per formula unit however some individual spot analyses have f cl deficiencies greater than analytical uncertainties that could represent structural oh on the basis of epma data the fluorapatite grain with the largest f cl deficiency constrains the upper limit of the oh content to be no more than 4600 2000 ppm by weight the equivalent of 2400 1100 ppm water the tof sims detection of oh in fluorapatite from apollo sample 15058 128 represents the first direct confirmation of structurally bound hydroxyl in a lunar magmatic mineral this result provides justification for attributing at least some of the missing structural component in the monovalent anion site of other lunar fluorapatite grains to the presence of oh moreover this finding supports the presence of dissolved water in lunar magmas and the presence of at least some water within the lunar interior

production of hydrogen peroxide in martian and lunar soils freshly ground basaltic minerals produce sufficient quantities of hydrogen peroxide h2o2 when immersed in solution to explain the oxidizing characteristics of martian soil samples collected by the viking landers h2o2 production occurs as a result of reactions between water and defects at the surface of mechanically pulverized minerals analogous to carcinogenic quartz dusts our results also indicate that dehydroxylation of mineral surfaces results in increased h2o2 production a highly relevant finding for dusts on the airless surface of the moon reactive pulverized minerals are important on planetary bodies where impact processes have generated fine grained basaltic dusts and may pose a significant health risk to astronauts visiting planetary surfaces where impacts have generated such materials

modern vertical deformation rates and mountain building in taiwan from precise leveling and continuous gps observations 2000 2008 1 to characterize the present day vertical displacement field in the active taiwan orogenic belt 1843 precise leveling and 199 continuous gps measurements from 2000 to 2008 are collected and analyzed in this study vertical velocities derived from the leveling data are placed in a reference frame of the chinese continental margin using continuous gps observations at nearby sites the leveling and gps vertical velocities generally reveal a dome shaped pattern with uplift of 0 2 18 5 mm yr in the interior of the mountain range and subsidence on the flanks of the mountains and coastal plains modern uplift rates in the active fold and thrust belt are generally consistent with geologic uplift rates however present day uplift rates in the central range are faster than the million years averaged exhumation rates the modern subsidence rates are generally consistent with geologic rates except for the rates in western coastal areas due to groundwater pumping present day subsidence in the southern central range and northern coastal range is however inconsistent with long term uplift which may reflect interseismic elastic strain accumulation across faults present day subsidence in northern taiwan occurs in a region of postcollisional orogenic collapse we model the present day and geologic vertical velocities and published gps horizontal velocity data across southern taiwan using a 2 d lithospheric model the model suggests a combined slip rate of 40 mm yr on the frontal thrusts and 45 mm yr on the longitudinal valley fault the model requires an additional source of crustal thickening under the central range to match the observed present day uplift rates

imaging of lunar surface maturity the physical evolution of the lunar surface with exposure to the space environment is termed maturation and maturity is the degree to which a particular lunar soil possesses quantitative characteristics consistent with that exposure several quantitative measures or indices of maturity have been proposed and employed including the abundance of solar wind gas abundance of various types of agglutinates various measures of grain size and is feo among the changes attendant with space exposure are striking changes in the optical characteristics of soils mature lunar soils are dark red and exhibit reduced spectral contrast relative to immature soils this paper presents an optical maturity index that quantifies the spectral effects of maturation we show that this optical maturity index correlates with other maturity indices about as well as the accepted maturity indices correlate among themselves and is only weakly coupled to composition the modest correlations among maturity indices suggest important controls on individual maturity indices other than age uncorrelated variations in the rates of accumulation of individual indicators or variations in depths over which indicators are emplaced in addition to mixing these effects conspire to reduce the equivalence of maturity and duration of surface exposure optical maturity illustrates some of these effects showing that ejecta of large and small craters mature at different rates and that the interiors and ejecta of large craters exhibit systematically different optical maturities the same or analogous effects are likely to influence other maturity indices

late pleistocene and early holocene glaciations in taiwanese mountains abstract the high mountain range of taiwan is unglaciated at present but numerous glacial landforms and sediments in three mountain massifs the nanhuta shan the hsueh shan and the yushan support the concept of repeated glaciations of these areas during the pleistocene and early holocene optically stimulated luminescence osl data derived from glacial and glacier related sediments suggests a glaciation about 8 9 0 5 ka called the nanhuta glacier advance which could be correlated either to the younger dryas or the global 8 2 ka cooling event alley et al 1997 holocene climatic instability a prominent widespread event 8200 yr ago geology 25 6 483 486 absolute data from pre holocene sediments are still rare although glacial evidence valley shape erratic boulders glacial trimlines and sediments indicates a larger extent of valley glaciers during the pleistocene

lithofacies types and vertical profile models an alternative approach to the description and environmental interpretation of glacial diamict and diamictite sequences abstract increased knowledge of modern glacial depositional environments has resulted in rapidly evolving classifications of glacial tills these are based to a large degree on theoretical considerations of likely depositional processes the classifications are sophisticated and more advanced than the establishment of simple field criteria whereby individual till facies can be identified in quaternary and pre quaternary successions this situation is compounded in many quaternary terrains by the continued description of tills in terms of laboratory derived analytical data only reflecting a traditional interest in stratigraphic correlation rather than reconstruction of depositional environment detailed sedimentological logging of lithofacies is rarely undertaken there is thus considerable confusion as to what is being described or sampled when analytical data are presented for many pleistocene tills the same remarks apply to pre pleistocene tillites a lithofacies code is presented here for the rapid description and visual appraisal of field sequences or drill cores containing unconsolidated diamicts or lithified diamictites the term till is not used as it has a strict genetic definition referring to direct aggregation and deposition by glacier ice use of a four part code in conjunction with codes already published for fluvial sediments allows fundamental field properties to be depicted independent of genetic terminology and provides a firm basis for subsequent environmental interpretation and analytical work the value of this approach is illustrated by comparing a representative suite of vertical profiles of diamict assemblages deposited by modern grounded glaciers with a classic late pleistocene glacigenic sequence at scarborough bluffs ontario

remote detection of magmatic water in bullialdus crater on the moon the remote detection of surface water indigenous to the moon has proved difficult because of alternative sources such as the solar wind spectroscopic observations of hydroxyl bearing materials in bullialdus crater by the chandrayaan 1 spacecraft are consistent with indigenous magmatic water that was excavated by impact from the lunar interior

surface deformation related to kink folding above an active fault evidence from geomorphic features and co seismic slips abstract by means of a geomorphological study using 40 m digital elevation model structural reconstruction by field data and related geodetic results we reevaluate the geomorphic features in the hsinshe area where multi step terraces have been previously documented and supposedly provide more information of the neotectonic history our results show that two kink shaped scarps can be discriminated from other terrace risers which are probably formed by folding instead of faulting as suggested by previous researchers two e w reconstructed hanging wall cross sections in the north and south show that the fault plane of chelungpu fault flattens to the east and sinks to the south creating a monoclinal hanging wall resembling a quarter hemisphere in terms of a 3d model we propose a kinetic model to explain the surface monocline fold it is developed when the fault plane presents a fault bend such as the case along the chelungpu fault at hsinshe the co seismic deformation from the 1999 chi chi earthquake demonstrates that the model is probably valid furthermore the higher terrace showing larger deformation indicates the influences of active structures on terraces have continuously acted for a long time the westward tilting of the hanging wall terraces result from the action of the chelungpu fault and its related structural geometry based on the optical stimulated luminescence age of 55 0 12 6 ka of the highest terrace we can compute the vertical rates across the main thrust and fold scarp in the hanging wall as 7 0 and 2 5 m kyr respectively

tomography the geoid and plate motions the dynamics of the earth s mantle and its relationship to mantle structure as revealed by seismic tomography the geoid and plate motions are discussed in a critical review of u s research from the period 1987 1990 sections are devoted to plates and mantle convection seismic anomalies flow and the geoid subducted slabs and the 670 km discontinuity the physical properties of the mantle plumes and computational and experimental modeling efforts also included is a comprehensive bibliography for the period 248 refs

surface modification of olivine by h and he bombardment laboratory simulations of solar wind irradiation of olivine a constituent of ordinary chondritic meteorites and s type asteroids show a dramatic chemical reduction of surface iron and to a lesser extent silicon earth s atmosphere oxidizes any reduced iron instantaneously whereas irradiated material on the surface of an asteroid would remain reduced changes in optical reflectance due to metallization of the surface provide a possible explanation for differences in the near infrared spectra of ordinary chondrite meteorites and their likely parent bodies the s iv asteroids

nanometer scale mineralogy and petrography of fine grained aggregates in anhydrous interplanetary dust particles abstract fine grained matrices in seven solar flare track rich anhydrous interplanetary dust particles idps were studied using 200 kev analytical electron microscopy the idps are u222b42 u220a19 u222b28 u230a3 w7027a11 w7027h14 u219 c2 and u219 c11 the matrices are composed of aggregates of glass disordered carbonaceous material and crystalline mineral grains with diameters between 1 and 150 nm the mineral grains were characterized using lattice fringe imaging electron microdiffraction and quantitative energy dispersive x ray spectroscopy eds the glasses were studied using eds and electron energy loss near edge structure analysis elnes three types of aggregates were observed unequilibrated equilibrated and reduced aggregates unequilibrated aggregates uas are 0 1 0 3 m diameter objects with bulk major element compositions that are approximately chondritic solar except for carbon they contain feni metal and fe rich sulfide crystals between 1 and 20 nm diameter embedded in silicate glass equilibrated aggregates eas are 0 1 to 1 m diameter objects that exhibit melt textures and mineralogy they contain fe bearing olivine and pyroxene grains with equilibrated fe mg ratios and fe sulfides embedded in feldspathic alumino silicate glass reduced aggregates ras are 0 1 to 1 0 m objects with feni metal feni carbides and fe rich sulfides embedded in a carbonaceous matrix the aggregates in the seven anhydrous idps appear to have formed in diverse physiochemical environments

concerning the dissipation of electrically charged objects in the shadowed lunar polar regions 1 nasa recently suggested the construction of a lunar outpost at the south pole near the rim of shackleton crater while there are a number of advantages to such a base the region will have periods of time when there is limited or no solar illumination thereby reducing photoelectric and solar wind plasma currents compared to most of the lunar dayside as a consequence of this reduction in environmental currents we find that human systems charged by contact electrification with the regolith e g roving excavation will have increased difficulty in removing accumulated electric charge this situation is especially true within the cold shadowed regions adjacent to the terminator such as within shackleton crater itself where there are essentially no photoelectric currents vastly reduced plasma currents due to the local wake and a highly reduced regolith conductivity in essence there is no pathway for accumulated charge to leak away or dissipate thereby creating an electrostatic hazard calculated dissipation timescales are found to be 1 millisecond in the weakly sunlit terminator region and dayside but could approach 100 s of seconds in the current starved shadowed regions

vesta s mineralogical composition as revealed by the visible and infrared spectrometer on dawn the dawn spacecraft mission has provided extensive new and detailed data on vesta that confirm and strengthen the vesta howardite eucrite diogenite hed meteorite link and the concept that vesta is differentiated as derived from earlier telescopic observations here we present results derived by newly calibrated spectra of vesta the comparison between data from the dawn imaging spectrometer vir and the different class of hed meteorites shows that average spectrum of vesta resembles howardite spectra nevertheless the vesta spectra at high spatial resolution reveal variations in the distribution of hed like mineralogies on the asteroid the data have been used to derive hed distribution on vesta reported in ammannito et al 2013 and to compute the average vestan spectra of the different hed lithologies reported here the spectra indicate that not only are all the different hed lithologies present on vesta but also carbonaceous chondritic material which constitutes the most abundant inclusion type found in howardites is widespread however the hydration feature used to identify carbonaceous chondrite material varies significantly on vesta revealing different band shapes the characteristic of these hydration features cannot be explained solely by infalling of carbonaceous chondrite meteorites and other possible origins must be considered the relative proportion of heds on vesta s surface is computed and results show that most of the vestan surface is compatible with eucrite rich howardites and or cumulate or polymict eucrites a very small percentage of surface is covered by diogenite and basaltic eucrite terrains are relatively few compared with the abundance of basaltic eucrites in the hed suite the largest abundance of diogenitic material is found in the rheasilvia region a deep basin where it clearly occurs below a basaltic upper crust however diogenite is also found elsewhere although the depth to diogenite is consistent with one magma ocean model its lateral extent is not well constrained

incision and channel morphology across active structures along the peikang river central taiwan implications for the importance of channel width river morphology and dynamics are strongly influenced by active tectonics we report channel dynamics for the peikang river which flows through the hsuehshan range in central taiwan using a digital elevation model and field surveys we constrain channel morphology for an 90 km stretch of river to calculate unit stream power and boundary shear stress along the river path incision rates are estimated with optically stimulated luminescence dating of sand deposited on strath terraces we find a strong correlation between unit stream power shear stress and incision rate but only if variation in channel width is considered a calibrated river incision rule implies river incision rates of 9 13 5 mm yr upstream of the meiyuan and tili faults and suggests that one or both of these structures are presently active our results indicate that the shuilikeng fault is also actively deforming as incision rates increase to 6 10 mm yr across it compared to 1 4 mm yr in adjacent reaches prominent narrowing across the shuilikeng fault and the absence of significant gradient variation indicate that channel width is a first order morphological adjustment to differential incision only when the channel width to depth ratio reaches a minimum does the channel slope significantly adjust to local changes in base level as is the case upstream of the meiyuan and tili faults

late holocene mobilisation of loess like sediments in hohuan shan high mountains of taiwan abstract silty cover soils are found in lower slope positions in the highest massifs of the high mountains of taiwan they are not formed under present day conditions and remain well preserved in locations not affected by fluvial morphodynamics this study focuses on an outcrop in the hohuan mountain summit area the sediment infill of a gully is described and sediment properties are analysed size frequency distributions of the sediment grains suggest that they are partly aeolian deposits the loess like sediments yielded osl ages between 3 65 0 62 ka and 1 72 0 48 ka results from radiocarbon dating of organic rich bulk sediments support the age estimates from osl the timing of gully infilling coincides with a cool and dry phase reported by palynological studies from toushe basin and chitsai lake the sediment record reflects a large scale climatic change to cooler and less humid conditions in the hohuan mountain area

the effects of adiabatic and viscous heatings on plumes we have assessed the influence of viscous and adiabatic heatings on the transient development of plumes by employing the time dependent convection equations in the extended boussinesq limit both temperature dependent and temperature and pressure dependent viscosities are employed for constant thermal expansion of coefficient we find the vigor of plume flows is diminished with larger magnitudes of the thermal expansivity this effects is caused by the local domination of adiabatic decompression over viscous heating inside the developing plume for both the cartesian and axisymmetric domains for deep mantle flows a thermal expansivity decreasing with depth is required for thin plume structures to exist values of the thermal expansivity contrast which can promote plume growth are in accord with estimates from recent studies in seismic equation of state copyright american geophysical union 1987

quantitative analysis of movement along an earthquake thrust scarp a case study of a vertical exposure of the 1999 surface rupture of the chelungpu fault at wufeng western taiwan a vertical exposure across the principal thrust scarp of the 1999 mw 7 6 earthquake allows quantification offault slip the exposure is located on the active chelungpu fault near wufeng along the range front of the fold and thrust belt in western taiwan the 1999 surface ruptures at the wufeng site are characterized by a west facing 2 to 3 m high principal thrust scarp and an east facing lesser backthrust scarp we mapped a 15 mlong 5 m deep exposure across the principal thrust scarp and characterized complex deformation structures which include a main basal thrust fault a wedge thrust and a pop up anticlinal fold with two secondary opposing thrust faults the vertical displacement across the principal thrust scarp is measured directly from the offsets of the same sedimentary horizons between the hangingwall and the footwall the average vertical displacement is 2 2 0 1 m and the maximum displacement is 2 5 m at the crest of the small pop up fold horizontal displacement estimates were determined using line and area balancing methods with line length methods we estimated a horizontal displacement of 3 3 0 3 m across the principal scarp for four sedimentary horizons for area balancing first we selected three horizontal soil sand deposits with a total thickness of about 0 5 m the estimate yields an average horizontal displacement of 4 8 1 0 m using these individual and relatively thin stratigraphic layers yielded significant standard deviations in displacement estimates as a result of thickness variations second we used the 3 mthick overbank soil sand and the lower part offluvial pebble cobble to calculate a horizontal displacement of 2 6 0 2 m with the area balancing technique according to the geometry of the dip angle 35 408 of the basal thrust the line length measurement and the 3 m thick package area balancing both providedreasonable results of horizontal displacement by comparing thedifferent deposits applied to theline and area balancing methods we interpret that decoupling of deformation occurred between the lower fluvial gravels and the upper overbank sand and mud deposits due to lesser confining pressure at the surface additional deformation occurred in the upper 1 2 m thick overbank deposits this additional deformation yielded further vertical uplift of 0 3 0 5 m and horizontal displacement of 0 2 0 8 m around the core of the pop up fold our work suggests that determination of slip across surface thrust ruptures varies as a function of the mechanical behavior of young late quaternary deposits q 2003 elsevier ltd all rights reserved

preliminary results of long term slip rates of 1999 earthquake fault by luminescence and radiocarbon dating for the purpose of deriving the long term slip rates of different segments along the surface rupture of 1999 chi chi earthquake radiocarbon and luminescence methods tl and osl were applied to the tectonically influenced geomorphic features and deposits we obtained six age estimates on pottery driftwood and fluvial sediments we found that the osl signals of the samples collected from the coarse fluvial deposits had not been totally bleached due to rapid deposition based on the cumulative vertical offsets the vertical slip rates were computed for each site our results reveal that the slip rate of the northern segment is relatively higher than that of the southern segment which is consistent with the coseismic offsets that occurred in the 1999 earthquake

late quaternary mass wasting records and formation of fan terraces in the chen yeo lan and lao nung catchments central southern taiwan abstract development of fan terraces in incision dominated river settings documents episodic increases of sediment supply from upland catchments in the non glaciated active mountains of taiwan such increases in sediment supply result typically from increases in landslide debris flow activity studying fan terraces therefore helps understand the history and nature of mass wasting processes eroding the mountains this study explores fan terrace successions developed at tributary mouths of the chen yeo lan and lao nung rivers in central southern taiwan judging from the spatial variations of sizes heights sequences and sedimentation of the fan terraces the magnitude and frequency of mass wasting activities appear to vary from tributary catchment to catchment two types of tributary catchment are differentiated which can be located in close proximity to each other one has been subject to extremely large but infrequent mass wasting events as a result of which high and or large fan terraces with 100 200 m thick debris flow fluvial gravels have been formed seven examples of this type of fan terrace have yielded radiocarbon dates of 40 ka 18 4 ka 13 9 ka 8 9 9 5 ka 3 9 4 8 ka 3 3 ka and 1 4 ka in age with the availability of multiple dates this type of fan terrace can be shown to have been created in no more than 1000 years from the aggradation of thick gravel sequences to subsequent incision the second type of catchment has been subject to relatively minor but frequent mass wasting events due to repeated incision after each such event the resultant fan terraces are relatively low and limited in size but have formed over lengthy periods although located in the same geological and geomorphic setting the dated fan forming mass wasting events in the chen yeo lan catchment do not appear to have occurred synchronously with those in the lao nung catchment nor could the succession of these events or their origins be clearly linked to known paleo climate data these findings highlight the importance of internal factors e g rock mass strength in determining the timing magnitude and frequency of mass wasting events in the studied mountains which are subject to active rock uplift highly active seismicity and intense rainfall

sedimentologic and geomorphic variations in storm generated alluvial fans howgill fells northwest england in june 1982 a storm with a return period greater than 100 yr but lasting less than 2 5 hr destabilized hillslopes and produced a suite of geomorphologically and sedimentologically diverse alluvial fans thirteen major fans were deposited at the tributary junctions between small 2 catchments and two north flowing headwater streams of the river lune northwest england storm generated fans spread over or became inset into older stable fans and produced localized vertical accretion of as much as 3 m and lateral accretion of as much as 100 m sedimentary processes operating during deposition involved debris flow transitional flow and streamflow six facies types are recognized on the basis of depositional topography sedimentary texture and fabric and matrix content viscous debris flow d1 dilute debris flow d2 transitional flow t1 fluvial bars and lobes s1 s2 and fluvial sheet gravels s3 regionally streamflow deposition prevails over debris flow deposition and type s3 facies has the greatest areal extent temporal and spatial variations in facies deposition during the storm however resulted from water sediment ratio variations fan deposition involved an early phase of debris flow to transitional flow due to large inputs of sediment from hillslope failures this was followed by a systematic change to more dilute conditions resulting in streamflow deposition and eventually in channel incision a significant amount of geomorphic work and complex variations in sedimentary processes during the storm resulted in part from extensive overland flow and hillslope destabilization discriminant analyses indicate that catchment size channel gradient and percentage of area eroded during the storm controlled whether debris flow or streamflow facies dominated a fan sequence smaller steeper catchments had a greater percentage of the area yielding sediment and are dominanted by debris flows whereas larger catchments produced more runoff resulting in dilution and streamflow the results indicate that the facies sequences and fan entrenchment in the howgill fells which are typically considered products of longer term climatic change or tectonics in other localities are here primarily affected by thresholds related to catchment geomorphology by the type of sediment available and by the position within the storm cell

polar hydrogen deposits on the moon neutron and gamma ray data measured using the lunar prospector spectrometers were analyzed to define the enhanced hydrogen deposits near both poles of the moon combining the new low altitude neutron data 30 15 km with previous high altitude 100 20 km neutron data and the results of several recent radar investigations sharply constrains the characteristics of each of the polar deposits the deposits at the north appear to be in the form of many small pockets or of generally distributed hydrogen that average to a 100 ppm weight fraction enhancement over that which exists in regolith at more equatorial latitudes those deposits in the permanently shaded craters near the south pole are consistent with a thick ferroan anorthosite regolith containing an enhancement of 1670 890 ppm hydrogen which if in the form of water ice amounts to 1 5 0 8 weight fraction of h sub 2 o neutron data alone cannot discriminate between hydrogen implanted in lunar soil from the solar wind hydrated minerals or h sub 2 o these craters appear to be surrounded by regolith that either contains small pockets of enhanced hydrogen or is soil that is uniformly impregnated with hydrogen enhanced on average by about 100 ppm above that contained in soils at more equatorial latitudes c more 2000 american geophysical union less

grain size distribution function of polymodal sediments in hydraulic and aeolian environments and numerical partitioning of the sedimentary components most continental sediments are polymodal composed of overlapping components of which the grain size generally obeys some type of natural distribution the grain size components and their function types can be determined from frequency and cumulative curve plots in order to define the function formula of the grain size distribution the function parameters can be estimated by fitting a defined function formula to the measured grain size data of the sample which simultaneously achieves numerical partitioning of the sedimentary components genetic analysis of grain size components of hydraulic and aeolian sediments demonstrates the following environmental implications fluvial sediment is composed of isolated saltation and suspension components the sediments in closed lake basins are dominated by a suspension silt clay component with a small proportion of saltation sand the fine sand component makes up the majority of desert sand overlapping with a small proportion of fine dust aeolian loess is composed of two overlapping components a short suspension time silt component and a long suspension time fine component aeolian material in the north pacific deep sea sediments is dominated by long suspension time fine dust the fine component in aeolian sediments shows a consistent grain size distribution and genetic connection from the desert sand loess of northern china to the north pacific ocean which is mainly transported by westerly winds and is dispersed in the atmosphere forming a background dust c 2002 elsevier science b v all rights reserved

compositional diversity and geologic insights of the aristarchus crater from moon mineralogy mapper data 1 the moon mineralogy mapper m3 acquired high spatial and spectral resolution data of the aristarchus plateau with 140 m pixel in 85 spectral bands from 0 43 to 3 0 m the data were collected as radiance and converted to reflectance using the observational constraints and a solar spectrum scaled to the moon sun distance summary spectral parameters for the area of mafic silicate 1 and 2 m bands were calculated from the m3 data and used to map the distribution of key units that were then analyzed in detail with the spectral data this analysis focuses on five key compositional units in the region 1 the central peaks are shown to be strongly enriched in feldspar and are likely from the upper plagioclase rich crust of the moon 2 the impact melt is compositionally diverse with clear signatures of feldspathic crust olivine and glass 3 the crater walls and ejecta show a high degree of spatial heterogeneity and evidence for massive breccia blocks 4 olivine strongly concentrated on the rim wall and exterior of the southeastern quadrant of the crater is commonly associated the impact melt 5 there are at least two types of glass deposits observed pyroclastic glass and impact glass

erosion rates and orogenic wedge kinematics in taiwan inferred from fission track thermochronometry new apatite and zircon fission track ages and previously published thermochronometric data are used to evaluate erosion rates and particle paths within the active taiwan arc continent collision we present 20 new apatite fission track ages and 6 new zircon fission track ages apatite and zircon ages are all reset in the northern and eastern parts of taiwan although the region of reset apatite ages is larger we interpret this pattern as resulting from crustal accretion at the western margin of the orogenic wedge combined with southward propagation of the collision zone a onedimensional thermal model including erosion provides prediction of the fission track ages the distribution of reset ages is best explained with an erosion rate of 4 6 mm yr given a propagation velocity of 60 mm yr this erosion rate implies that nearly 25 km of material has been eroded from northern taiwan the lack of reset 40 ar 39 ar ages from muscovite and biotite suggests that rockparticle paths have a large horizontal component a result consistent with an eroding orogenic wedge model