sea cliffs their processes profiles and classification general concavity or convexity of sea cliff profiles is controlled by relative rates of erosion by marine and subaerial processes as well as by positions of more resistant strata in the cliffs profiles supplemented by on site examination can establish the activity and dominance of erosional processes and indicate changes in regimen a sharp angle at the sea cliff base generally indicates active marine erosion whereas a smooth curve at the base means that subaerial erosion may dominate talus shows absence of marine erosion studies of profiles can be useful for estimating stability for residences railroads and highways at the top face and base of sea cliffs generally increased erosion and retreat of sea cliffs are in prospect because of projected regionally wetter and stormier climate rising sea level and increased human activities

fire ecology of the carboniferous tropical zone abstract fossil charcoal fusain indicating the occurrence of wildfire is common in the carboniferous rocks of north america and europe during the carboniferous these regions lay on the southern margins of the laurasian continent and within the tropical zone this study examines the facies distribution and botanical identity of charcoal in order to investigate the influence of fire on carboniferous tropical ecology new data from charcoal bearing units in eastern canada poland and the british isles are presented and synthesised with previously published data of charcoal occurrence tournaisian visean charcoal bearing strata were deposited in volcanic lacustrine alluvial plain and coastal marine environments in these deposits charred floras are dominated by pro gymnospermous plants whilst uncharred compressed or permineralised floras are dominated by lycopsids uncharred lycopsid remains were probably derived from wetland communities growing close to the depocentres whilst charred gymnospermous remains may have been sourced from well drained extrabasinal settings based on the vertical distribution of charcoal layers in annually laminated lacustrine deposits it is estimated that fires occurred with high frequency approximately every 3 35 years palaeoclimatic analysis indicates that southern laurasia at this time was subject to a seasonal monsoonal tropical climate such environments today are characterised by tropical savannas with high fire frequencies and early carboniferous fire prone gymnospermous plant communities may have represented a comparable vegetation biome namurian stephanian charcoal bearing strata were deposited in alluvial plain coastal plain and coastal marine environments channelised sandstone units interpreted as river channel deposits contain charcoal derived from cordaitaleans and conifers this assemblage records fires in extrabasinal coniferopsid forests mudstone units containing coals are interpreted as the deposits of floodbasins and peat mires hollow uncharred lepidodendrid stumps occur in this facies and contain lepidodendrid charcoal in the stump bases and lepidodendrid pteridosperm coniferopsid and sphenopsid charcoal outside the stumps this assemblage records fires in wetland lepidodendrid dominated forests lepidodendrid trunks comprising of a spongy parenchymatous core surrounded by dense periderm became hollowed out during fire events an estimate of fire frequency based on the vertical spacing of charcoal layers in coals implies that fires occurred every 105 1085 years in the peat mires palaeoclimatic analysis indicates that southern laurasia was subject to a humid tropical climate during the late carboniferous such environments today are characterised by tropical rainforests where fires occur rarely and late carboniferous communities may have represented a comparable biome

the pre quaternary history of fire abstract although evidence for land vegetation comes from the silurian and maybe even earlier the first record of fossil charcoal fusain is from the late devonian for this period there are only one or two isolated records not until the early carboniferous is there a record of extensive charcoal deposits mainly preserved in near shore clastic sediments which provide evidence of significant and widespread wildfires by the late carboniferous charcoal was common or abundant in a wide range of facies including tropical wetland peats wildfire played an important role in shaping the environment at this time the latest palaeozoic and early mesozoic records of charcoal are fewer whereas important deposits of late mesozoic age are found worldwide the occurrence of charcoal at the cretaceous tertiary boundary has been highlighted as evidence for a global fire following a meteorite impact but this interpretation is questionable charcoal has been widely reported from tertiary sediments and its appearance in the quaternary and recent is not solely as a result of human impact through the past 400 million years there have been major changes in atmospheric oxygen levels that affected fire intensity and frequency fire systems thus have a long history and their impact on shaping the environment is assessed

a critical re examination of the petrology of the no 5 block coal in eastern kentucky with special attention to the origin of inertinite macerals in the splint lithotypes abstract the pennsylvanian no 5 block coal bed in eastern kentucky is one of several coals considered to be among the splint coals of the central appalachians the coals are generally noted for their inertinite rich dull lithotypes petrographic aspects of the lithologies reveal both fire derived and degradation derived inertinites in the assemblages fire is not an exclusive contributor to the origin to inertinite macerals there are many other biological factors such as the actions and interactions of fungi bacteria and insects which must be considered in the alteration of plant materials to form inertinite macerals fungi physically and chemically alter plant tissues to form macerals with a distinct morphology and chemistry different than those formed from fire and other abiological processes insects as secondary sources of wood degradation within a mire are responsible for physical such as boreholes from wood consuming insects and chemical alteration of plants degradation observed in macrinite may be boreholes from wood consuming insects such as mites some inertinite macerals in particular macrinite may be the result of inert fecal pellet conglomerates preserved in the mire overall macerals of the same name can form from multiple and complex biological and abiological processes

measuring geomorphological diversity on coastal environments a new approach to geodiversity abstract geodiversity can be defined as the spatial variability of geo elements its emergence as a research field is relatively recent with a wide range of approaches and methods of evaluation and quantification already in use the work described in this paper was carried out from a novel perspective firstly the emphasis is specifically centred on geomorphological diversity secondly mathematical ecology calculations are applied which tackle the problem on the basis of a larger number of diversity parameters in addition whereas most authors have focussed on mountainous and or continental areas for the first time a study of this type is applied to coastal landscapes the analysis covers the full 459 km of volcanic coastline of the islands of gran canaria and la palma canary islands these two oceanic islands were chosen for purposes of diversity comparison given their differing stages of geomorphic development in accordance with an ad hoc geomorphological taxonomy as developed in this study 14 geomorphic groups and 42 subgroups were identified and quantified according to their presence 1 or absence 0 along the coastline a cartographic analytical method coastline data storing or cds based on the computation of binary information in the cartographic vector of the coastline enabled calculation of the occurrence probability of these groups and subgroups both at local level analyses of coastal morphoassemblages and general level three components of geomorphological diversity richness evenness and dissimilarity were estimated through indices of richness r shannon s entropy h and rao s quadratic entropy q the data reveal that geomorphological coastal diversity is between 11 1 and 48 2 higher in gran canaria than in la palma the method was subjected to a fractal stress test through iterative mapping procedures to assess the effect of scale on the behaviour of the relative frequencies and indices the variability that was obtained allowed the extraction of corrected values in the indices for la palma h c 1 88 0 008 and qc 0 183 0 004 and gran canaria h c 2 11 0 019 and qc 0 232 0 003 a moving window test was also applied as a rarefaction method to confirm the contrast in diversity in coasts of different size the results enabled to advance hypotheses about the relation between coastal geomorphic diversity and geological age of islands

observations and experiments on the origin and formation of inertinite group macerals the inertinite group macerals include fusinite semifusinite inertodetrinite macrinite micrinite and funginite and secretinite which together replace sclerotinite the macrolithotype fusain comprises fusinite and semifusinite and is now widely accepted as charcoal formed by wildfire activity however alternative origins for fusinite and semifusinite are still claimed this paper considers the use of the terms pyrofusinite degradofusinite rank fusinite and primary fusinite misleading while the definitions of the terms funginite and secretinite are also considered problematic observations made on modern wildfire derived and volcanogenic charcoal assemblages using reflectance and scanning electron microscopy together with experimental charcoalification studies demonstrate that most if not all inertinite macerals have acquired their optical and physical characteristics through the action of elevated temperatures the criteria for the identification of charcoals produced by wildfire and volcanic activity are outlined and the role of the petrographic nomenclature system is discussed

east asian gold deciphering the anomaly of phanerozoic gold in precambrian cratons early cretaceous orogenic gold deposits in eastern asia are globally unique in that large phanerozoic lode gold deposits occur in archean paleoproterozoic cratons in the northern pacific region ca 125 ma orogenic gold deposits in the north china yangzte and siberian craton margins as well as in young terranes in california may ultimately relate to the giant cretaceous mantle plume in the southern pacific basin and the relatively rapid tectonic consequences along both continental margins from resulting pacific plate reconfigurations in eastern asia such consequences include reactivation of and fluid flow along major fault systems with fluid focusing into simultaneously forming isolated core complexes of uncertain genesis deposition of gold ores in previously devolatilized high grade precambrian metamorphic rocks requires an exotic source of ore fluid most likely subducted mesozoic oceanic crust and or overlying sediment an implication is that phanerozoic metamorphic core complexes in other destabilized craton margins could host large gold resources

molybdenum tungsten and manganese partitioning in the system pyrrhotite fe s o melt rhyolite melt impact of sulfide segregation on arc magma evolution abstract experiments were performed to determine the partitioning of molybdenum tungsten and manganese among a rhyolitic melt melt pyrrhotite po and an immiscible fe s o melt fe s o sulfide phases such as these may be isolated from a silicate melt along with other crystallizing phases during the evolution of arc magma and partition coefficients are required to model the effect of this process on molybdenum and tungsten budgets we developed an experimental design to take advantage of properties of the phases under study careful control of temperature allowed pyrrhotite and magnetite to be stable along with an fe s o melt and this phase assemblage allowed the composition of run product pyrrhotite to be used to calculate both fs2 and fo2 for the experiments at run temperature 1042 2 c a rhyolitic melt can be formed at low pressure under nominally dry conditions which removed the need for confining pressure as well as externally imposed fugacities the silica saturated melt allowed the charges to be contained in sealed evacuated silica tubes without danger of reaction and with closed system behavior for molybdenum and tungsten experiments were run for durations up to 2000 min molybdenite mb and wolframite wo were added to the experiments as sources for molybdenum and tungsten respectively manganese was added to the system as both a component of the starting rhyolitic pumice and of mn bearing wolframite oxygen fugacity in these experiments was fixed at the ni nio oxygen fugacity buffer sulfur fugacity was 10 1 bar run products were analyzed by epma and la icp ms analysis of the run products yielded d i a b 1 x standard deviation of the mean d mo fe s o si melt 90 10 d w fe s o si melt 9 3 d mo po si melt 35 3 and d w po si melt 0 0012 0 0006 the partition coefficients for manganese in this system are d mn fe s o si melt 2 9 0 3 and d mn po si melt 1 1 0 1 simple rayleigh fractionation modeling suggests that oxidized felsic melts produced through fractional crystallization may have lost as much as 14 of their initial molybdenum but only 2 of their initial tungsten through the removal of an fe s o melt along with crystalline phases modeling consistent with conditions of oxygen and sulfur fugacity influenced by assimilation of sulfide with low concentrations of molybdenum and tungsten from for example sedimentary rock results in evolved magmas significantly depleted in molybdenum but only moderately depleted in tungsten the molybdenum tungsten ratio can vary by two orders of magnitude these systematics may help to explain some of the variability in metal ratios of intrusion related hydrothermal ore deposits

apatite chemical composition determined by electron microprobe and laser ablation inductively coupled plasma mass spectrometry as a probe into granite petrogenesis abstract major minor and trace element abundances in apatites from various i and s type igneous and sedimentary granites of the lachlan fold belt have been determined using electron microprobe and laser ablation inductively coupled plasma mass spectrometer the results show that apatite can accommodate many minor and trace elements whose concentrations and ratios are relatively sensitive to factors controlling many of the fundamental differences between i and s type granites apatites from s type granites generally have higher f but lower cl contents than those from i type granites which is ascribed mainly to the loss of cl during the weathering processes forming the source rocks of s type granites although fractional crystallisation can cause significant enrichment in f as well high mn and fe contents in apatites from s type granites and high s and as abundances in apatites from mafic i type granites result from different oxygen fugacities and degrees of al saturation or aluminosity between metaluminous mafic i type magmas and peraluminous s type and felsic i type magmas there are systematic and distinctive differences in absolute rare earth element ree abundances ree distribution patterns and element ratios e g la y sm nd etc between apatites from different types of granite the strong eu depletion that characterises apatites from s and felsic i type granites is interpreted here to be a result of the uniqueness of crystal chemistry of apatite and high eu2 eu3 ratios in s type and felsic i type magmas which are more reduced and peraluminous than mafic i type magmas strong ree la to eu and th enrichment in apatites from mafic i type granites and marked nd depletion in apatites from most s type and felsic i type granites are caused by the precipitation and fractionation of monazite in the parental magmas of the latter rocks substitution mechanisms are responsible for high na in apatites from s type and felsic i type granites and for high si in apatites from mafic i type granites and may also have important effects on ree partitioning between apatite and melt thus apatite chemistry can be used as an excellent indicator of granite petrogenesis the results have important implications for identifying different types of granite and are potentially significant for determining the provenance of sedimentary rocks

charcoal in the silurian as evidence for the earliest wildfire rare basal pridoli plant fossils which resemble the rhyniophytoid hollandophyton colliculum and have exceptional three dimensional cellular anatomy are preserved as charcoal as such these fossils from ludford lane in the welsh borders are evidence of the earliest recorded wildfire and are the first documented from before the devonian the fossils represent the charred remains of a low growing low diversity in situ rhyniophytoid or cryptospore bearing plant vegetation charred during a low temperature fire

early cretaceous adakitic granites in the northern dabie complex central china implications for partial melting and delamination of thickened lower crust abstract to date few adakitic rocks have been reported in direct association with contemporary intra continental extensional structures which has cast doubt on genetic models involving partial melting of the lower crust this study presents early cretaceous 143 129 ma new sensitive high resolution ion microprobe shrimp zircon u pb ages adakitic granites which are directly associated with a contemporary metamorphic core complex i e the northern dabie complex in the dabie area these granites exhibit relatively high sr contents negligible to positive eu and sr anomalies high la yb and sr y ratios but very low yb and y contents similar to subducted oceanic crust derived adakites they are also characterized however by very low mgo or mg and ni values and nd sr isotope compositions end t 14 6 to 19 4 and 87sr 86sr i 0 7067 0 7087 similar to triassic continent derived eclogites subducted in the dabie sulu orogen additionally late granitic dikes in the adakitic intrusions exhibit low sr contents clearly negative eu and sr anomalies low la yb and sr y ratios but relatively high yb and y contents similar to 118 105 ma granites in the northern dabie complex based on composition and geochronology data of neoproterozoic amphibolites and orthogneisses triassic high to ultra high pressure metamorphic rocks and early cretaceous mafic ultramafic intrusive rocks and the constraints provided by experimental melt data for tonalites metabasaltic rocks and eclogites we suggest that the adakitic granites were most probably generated by partial melting of thickened amphibole or rutile bearing eclogitic lower crust as a consequence of triassic middle jurassic subduction and thrusting the late dikes probably originated from plagioclase bearing intermediate granulites moreover we suggest that late mesozoic delamination or foundering of thickened eclogitic lower crust is also a more plausible mechanism for the petrogenesis of early cretaceous mafic ultramafic intrusive rocks in the dabie area and probably involved partial melting of a mixed source comprising eclogitic lower crust that had delaminated or foundered into upper lithospheric or asthenospheric mantle peridotite asthenospheric upwelling in response to post collisional delamination of lithospheric mantle was likely to have provided the heat source for the cretaceous magmatism

upper quaternary coastal palaeoenvironments and palaeosea levels in las canteras beach gran canaria canary islands spain abstract las canteras beach outcrops are vestiges of palaeoenvironments that represent changes in sea level and or climate conditions using broad sedimentological mineralogical geochemical and dating studies three different palaeoenvironmental facies were distinguished 1 the lower facies was defined as beachrock formed by decametric calcarenite layers dipping 8 5 seaward and composed mainly of sand grains and two generations of isopachous low magnesium calcite lmc cement in a context of lower holocene interglacial stage 6600 30 cal years bp rising sea level and coastal progradation 2 during the middle holocene about 6600 30 cal years bp a coastal progradation phase and or lower sea level might lead to land emersion and soil development with an abundance of terrestrial gastropods 3 the upper holocene

geodiversity of high latitude landscapes in northern finland abstract geodiversity is a rather new emerging topic in earth science there is now increased awareness of our need to understand patterns of geodiversity in different landscapes facing global change in this study we systematically inventoried geodiversity and topographical parameters in an area of 285 km 2 in subarctic finland we quantified the spatial variation of geodiversity using four different measures and analysed the relationship between geodiversity and topography using a spatial grid system at a landscape scale the size of the analysis window was 500 500 m the number of different elements of geodiversity total geodiversity varied from 2 to 22 per grid cell the spatial pattern of the total geodiversity geomorphological process variability and geodiversity index were fairly similar whereas of the other geodiversity measures the measure of temporal diversity differed the most topographically the high diversity sites occurred in rather steep sided valleys areas of high geodiversity reflect heterogeneous abiotic conditions where both erosion and accumulation processes play a major role in landscape development the mapping of geodiversity may be indicative not only in the context of geomorphology but also provide a focus for conservation initiatives from a conservation point of view the lack of wider knowledge of the distribution of geodiversity and its relationship to biodiversity hinders the protection of ecologically and geomorphologically valuable regions thus we recommend that further studies focus on 1 quantifying spatial patterns of geodiversity in different regions 2 determining the key drivers that control the variability of geodiversity and 3 exploring the linkage between geodiversity and biodiversity

hotspot volcanism close to a passive continental margin the canary islands the canarian archipelago is a group of volcanic islands on a slow moving oceanic plate close to a continental margin the origins of the archipelago are controversial a hotspot or mantle plume a zone of lithospheric deformation a region of compressional block faulting or a rupture propagating westwards from the active atlas mountains fold belt have been proposed by different authors however comparison of the canarian archipelago with the prototypical hotspot related island group the hawaiian archipelago reveals that the differences between the two are not as great as had previously been supposed on the basis of older data quaternary igneous activity in the canaries is concentrated at the western end of the archipelago close to the present day location of the inferred hotspot this is the same relationship as seen in the hawaiian and cape verde islands the latter archipelago associated with a well defined but slow moving mantle plume shows anomalies in a plot of island age against distance which are comparable to those seen in the canary islands these anomalies cannot therefore be used to argue against a hotspot origin for the canaries individual islands in both archipelagoes are characterized by initial rapid growth the shield building stages of activity followed by a period of quiescence and deep erosion erosion gap which in turn is followed by a post erosional stage of activity the absence of post shield stage subsidence in the canaries is in marked contrast with the major subsidence experienced by the hawaiian islands but is comparable with the lack of subsidence evident in other island groups at slow moving hotspots such as the cape verdes comparison of the structure and structural evolution of the canary islands with other oceanic islands such as hawaii and reunion reveals many similarities these include the development of triple mercedes star rift zones and the occurrence of giant lateral collapses on the flanks of these rift zones the apparent absence of these features in the post erosional islands may in part be a result of their greater age and deeper erosion which has removed much of the evidence for their early volcanic architecture we conclude that the many similarities between the canary islands and island groups whose hotspot origins are undisputed show that the canaries have been produced in the same way

rare earth elements in apatite as a monitor of magmatic and metasomatic processes the ilimaussaq complex south greenland abstract textural and compositional variations of apatite from the plutonic ilimaussaq complex in south greenland and its surrounding country rocks track magmatic and metasomatic processes detailed back scattered electron bse imaging reveals various types of apatite textures including i growth zonation concentric oscillatory as well as sector zonation formed during magmatic differentiation ii resorption and overgrowth textures due to fluid melt induced metasomatic overprint of precursor apatite and iii replacement textures indicating the destabilization of apatite in favor of monazite in the least evolved rocks of the ilimaussaq complex apatite incorporates rare earth elements and y rey mainly via the coupled substitution ca 2 p 5 rey 3 si 4 in the more evolved peralkaline rocks and in metasomatically overprinted rocks however the coupled substitution 2 ca 2 rey 3 na becomes increasingly relevant and apatite incorporates successively more lree compared to hree as shown by increasing la gd n and gd yb n ratios similarly at the contact between the ilimaussaq rocks and the granitic country rocks the metasomatic effect of the emplacement of the ilimaussaq melts is preserved in partly resorbed precursor apatite which is overgrown by rey enriched apatite with higher la gd n and gd yb n ratios compared to apatite from granites more distant from the contact this study shows that apatite textures and compositions are suitable to track both primary magmatic and later fluid present metasomatic processes the incorporation of rey in apatite is not only dependent on the amount of rey present but also depends largely on na activity in the apatite precipitating melts and fluids

an experimental study of trace element partitioning between zircon and melt as a function of oxygen fugacity abstract the partitioning of p sc ti sr y nb the rare earth elements ree hf ta th and u between zircon and a synthetic andesitic melt was determined as a function of oxygen fugacity f o 2 over a range of fourteen log units from qfm 8 to qfm 6 where qfm is the quartz fayalite magnetite oxygen buffer at 1300 c and 1 atm using sims and la icp ms the partition coefficients of ce and eu were found to vary systematically with f o 2 relative to those of the other ree producing ce and eu anomalies similar to those that are characteristic of natural igneous zircon these anomalies coexist at terrestrial f o 2 s and were used to quantify eu 3 eu 2 eu 3 and ce 4 ce 3 ce 4 in the melt the partition coefficients of the redox invariant trivalent cations are in excellent agreement with lattice strain theory the values of d ree are related to those determined for natural samples by the expected dependence on temperature the incorporation of ree 3 in zircon was independent of the presence of p d u d th was found to vary systematically with f o 2 indicating the presence of u 4 u 5 and u 6 in the melt at terrestrial conditions d ti was independent of f o 2 despite an expectation of significant ti 3 in the most reduced experiments

relative oxidation states of magmas inferred from ce iv ce iii in zircon application to porphyry copper deposits of northern chile major and trace element compositions of zircons and whole rocks from 14 barren and seven ore bearing calc alkaline intrusions from the chuquicamata el abra porphyry copper belt of northern chile have been measured in situ by excimer laser ablation ela icp ms these data permit the ce iv ce iii ratio within zircon to be calculated using a lattice strain model for mineral melt partitioning of ce iv and ce iii zircon ce iv ce iii and eun eun ratios and by inference magmatic oxidation states generally increase from older mafic to younger felsic units within this sequence porphyry copper mineralization is directly associated only with intrusions with zircon ce iv ce iii 300 and eun eun 0 4 such trends can be understood in terms of interdependent relations between oxygen fugacity sulfur speciation and solubility and chalcophile element partitioning in silicate magmas because zircon occurs in most calc alkaline intrusions and is resistant to subsolidus alteration zircon ce iv ce iii ratios provide a useful tool for evaluating the economic potential of such rocks for magmatic hydrothermal cu au mineralization the approach is general and may provide a means to infer relative oxidation state in a wide range of intermediate to felsic igneous rocks

water column anoxia enhanced productivity and concomitant changes in δ13c and δ34s across the frasnian famennian boundary kowala holy cross mountains poland the investigation of the trace element and organic geochemistry of the frasnian famennian boundary section at kowala holy cross mountains poland shows that the lower water column was oxygen deficient during late frasnian and early famennian times the abundance and carbon isotopic composition of diaryl isoprenoids biomarkers indicative for green sulfur bacteria prove that euxinic waters reached into the photic zone at least episodically total organic carbon toc contents show two maxima that are time equivalent to the kellwasser horizons deposited in shallower water settings enhanced toc concentrations are explained by a higher primary productivity presumably as a consequence of an enhanced nutrient supply from the continent the increase in the abundance of hopanes and bituminite suggests that the bacterial contribution to toc increased at the frasnian famennian transition the sulfur isotopic composition of pyritic and organically bound sulfur shows a 27 excursion across the boundary the observation that the 34s values of organic bound sulfur closely resemble that of pyrite sulfur indicates a common sulfur source likely early diagenetic sulfide a change in the 13c of total dissolved inorganic carbon as a consequence of an enhanced burial of 12c enriched organic carbon is indicated by a 3 excursion measured for toc as well as for individual n alkanes and isoprenoids the burial of large amounts of organic carbon is expected to result in a decrease in pco2 and should affect the photosynthetic carbon isotope fractionation ep the fact that we observe no change in ep can be explained by the circumstance that ep was most probably at maximum values as a consequence of high atmospheric and oceanic dissolved co2 concentrations during the devonian

controls on coastal dune morphology shoreline erosion and barrier island response to extreme storms abstract the response of a barrier island to an extreme storm depends in part on the surge elevation relative to the height and extent of the foredunes which can exhibit considerable variability alongshore while it is recognized that alongshore variations in dune height and width direct barrier island response to storm surge the underlying causes of the alongshore variation remain poorly understood this study examines the alongshore variation in dune morphology along a 11 km stretch of santa rosa island in northwest florida and relates the variation in morphology to the response of the island during hurricane ivan and historic and storm related rates of shoreline erosion the morphology of the foredune and backbarrier dunes was characterized before and after hurricane ivan using empirical orthogonal function eof analysis and related through canonical correlation analysis cca the height and extent of the foredune and the presence and relative location of the backbarrier dunes varied alongshore at discrete length scales of 750 1450 and 4550 m that are statistically significant at the 95 confidence level cospectral analysis suggests that the variation in dune morphology is correlated with transverse ridges on the inner shelf the backbarrier cuspate headlands and the historical and storm related trends in shoreline change sections of the coast with little to no dune development before hurricane ivan were observed in the narrowest portions of the island between headlands west of the transverse ridges overwash penetration tended to be larger in these areas and island breaching was common leaving the surface close to the watertable and covered by a lag of shell and gravel in contrast large foredunes and the backbarrier dunes were observed at the widest sections of the island the cuspate headlands and at crest of the transverse ridges due to the large dunes and the presence of the backbarrier dunes these areas experienced less overwash penetration and most of the sediment from the beachface and dunes was deposited within the upper shoreface it is argued that this sediment is returned to the beachface through nearshore bar migration following the storm and that the areas with larger foredunes and backbarrier dunes have smaller rates of historical shoreline erosion compared to areas with smaller dunes and greater transfer of sediment to the washover terrace since the recovery of the dunes will vary depending on the availability of sediment from the washover and beachface it is further argued that the alongshore pattern of dune morphology and the response of the island to the next extreme storm is forced by the transverse ridges and island width through alongshore variations in storm surge and overwash gradients respectively these findings may be particularly important for coastal managers involved in the repair and rebuilding of coastal infrastructure that was damaged or destroyed during hurricane ivan

notes on the origin of inertinite macerals in coals observations on the importance of fungi in the origin of macrinite macrinite is a generally rare inertinite maceral often incorporating remnants and fragments of other macerals including vitrinite liptinite and other inertinite the associated inertinites include multiple forms of funginite funginite is also commonly found in association with vitrinite of slightly elevated reflectance and with degraded varieties of vitrinite together with the highly degraded macrinite the latter two associations are here inferred to be part of a continuum of fungal and microbial degradation of peat in any case the origin of some macrinite is potentially distinct from that of inertinite generated by fire

are discontinuous chondrite normalized ree patterns in pegmatitic granite systems the results of monazite fractionation abstract all 14 stable rare earth elements rees in biotite muscovite granite and tourmaline rich granite of the harney peak granite black hills south dakota usa have been analyzed using inductively coupled plasma mass spectrometry chrondrite normalized ree patterns of the tourmaline rich granites are discontinuous between nd and sm the discontinuity was modeled successfully by the fractional crystallization of monazite from a biotite muscovite granite initial composition this explanation may also apply to the development of such discontinuous patterns in other highly evolved rocks

coesite bearing eclogite from the dabie mountains in central china coesite and coesite pseudomorphs are recognized in eclogite from the dabie mountains a collision zone between the sino korean and yangtze cratons in central china this third known occurrence of coesite in deep crustal rocks is within an archean gneiss terrane and is the first locality where coesite has been identified as an inclusion in both omphacite and garnet crystals at the same location coesite bearing eclogite is estimated to form at pressures of 28 kbar and temperatures from 600 to 710 c the dabie mountains eclogite underwent retrograde metamorphism to amphibolite facies after its formation the preservation of coesite in eclogite is found to be strongly controlled by the pressure temperature time path that coesite bearing eclogite followed during its uplift and retrograde metamorphism

can geodiversity be predicted from space abstract identification of geodiversity at regional and national scales with traditional surveying techniques remains a logistically difficult and often financially prohibitive task earth observation data in combination with statistical modeling may provide a unique approach for mapping and analyzing geodiversity cost efficiently in this study the possibility to map geodiversity using digital elevation models dems and remote sensing rs data was scrutinized in finland northern europe at a landscape scale the main methods in the evaluation of spatial prediction ability of geodiversity and the relative contributions of dem and rs data were generalized additive modeling gam and variation partitioning based on the results geodiversity was mainly determined by polygenetic bedrock topography and fluvial activity and correlated most strongly with variables describing high potential energy and topographical heterogeneity the spatial patterns of geodiversity were robustly predicted across the study areas using multivariate gams the higher predictive performance of the dem versus rs based variables was evident across the study areas in conclusion we propose that statistically based spatial prediction offers an opportunity for characterizing geodiversity of a large area in a systematic repeatable and spatially exhaustive manner

spatial characterization resolution and volumetric change of coastal dunes using airborne lidar cape hatteras north carolina the technological advancement in topographic mapping known as airborne light detection and ranging lidar allows researchers to gather highly accurate and densely sampled coastal elevation data at a rapid rate the problem is to determine the optimal resolutions at which to represent coastal dunes for volumetric change analysis this study uses digital elevation models dem generated from lidar data and spatial statistics to better understand dune characterization at a series of spatial resolutions the lidar data were collected jointly by the national aeronautics and space administration nasa the national oceanic and atmospheric administration noaa and the u s geological survey usgs dems of two study sites 100 200 m located in cape hatteras national seashore north carolina were generated using a raster based geographic information system gis changes in the dune volume were calculated for a 1 year period of time fall 1996 1997 at grid cell resolutions ranging from 1 1 to 20 20 m directional statistics algorithms were used to calculate local variance and characterize topographic complexity data processing was described in detail in order to provide an introduction to working with lidar data in a gis results from these study sites indicated that a 1 2 m resolution provided the most reliable representation of coastal dunes on cape hatteras and most accurate volumetric change measurements results may vary at other sites and at different spatial extents but the methods developed here can be applied to other locations to determine the optimum resolutions at which to represent and characterize topography using common gis and database software

petrogenesis of early cretaceous post collisional granitoids at shapinggou dabie orogen implications for crustal architecture and porphyry mo mineralization abstract the shapinggou molybdenum deposit is located in the qinling tongbai hong an dabie orogen which accommodates the largest molybdenum ore belt in the world new laser ablation inductively coupled plasma mass spectrometry la icp ms zircon u pb dating geochemical and sr nd hf isotope data for the granitoids at shapinggou are presented in this paper two stages of early cretaceous magmatism 138 128 ma and 116 114 ma took place at shapinggou in a post collisional setting these granitoids can be divided into four groups including the early stage granites 134 129 ma sio2 62 33 to 76 27 and intermediate rocks 129 128 ma sio2 52 41 to 60 72 and the late stage quartz syenite 116 ma sio2 64 09 to 65 12 and mo bearing granite porphyry 114 ma sio2 74 95 to 77 26 the early stage granites have high sr contents sr y and lan ybn ratios but low y yb and mgo contents showing low mg adakitic chemical features they were possibly generated by partial melting of the thickened mafic lower continental crust the early stage intermediate rocks have relatively high mgo contents 2 71 to 4 84 and mg values 46 to 60 but low sr y and lan ybn ratios which were likely derived from a hybrid mantle metasomatized by melts from foundered eclogitic lower continental crust and subsequent fractional crystallization the late stage quartz syenite shows chemical features of metaluminous a type granites including high abundances of alkalis hfse zr nb and trivalent ree the late stage mo bearing granite porphyry displays high sio2 alkalis zr ce contents and a cnk ratios but low ba sr p and ti showing affinity to highly fractionated i type granites the late stage quartz syenite and granite porphyry were possibly produced by partial melting of intermediate compositions of middle crust our results support the conclusion that there were three layer continental crusts in the dabie orogen prior to early cretaceous magmatism and suggest that post collisional granitoids in the dabie orogen were derived from not only lower crust but also middle crust the giant shapinggou porphyry mo deposit was most likely formed by effective transport of volatiles and mo in a convecting granitic magma column rather than by direct melting of mo enriched sources the mo bearing rocks at shapinggou are characterized by a high degree of magma differentiation close associations with a type granite and formation at the end of regional magmatism

40ar 39ar dating of strike slip motion on the tan lu fault zone east china abstract ne trending sinistral ductile shear belts in the southern part of the tan lu fault zone east china are exposed along the eastern edge of the northern dabie belt and southern zhangbaling belt three hornblende three phengite and 12 biotite separates from greenschist facies mylonites in the shear belts were dated by the 40ar 39ar method in this study a hornblende plateau age of 143 3 ma is interpreted as representing the time of sinistral motion on the zhangbaling part of the tan lu fault zone seven biotite samples from the same part yield 40ar 39ar cooling ages from 137 to 125 ma a phengite plateau age of 138 8 ma from the eastern edge of the dabie belt is considered as being close to the time of deformation in the tan lu strike slip zone five biotite 40ar 39ar ages from 120 to 110 ma and one phengite age of 121 ma from the same area represent cooling ages after the sinistral faulting it is concluded on the basis of these 40ar 39ar ages that the sinistral ductile shear belts in the southern part of the tan lu fault zone were produced in earliest early cretaceous this sinistral motion on the tan lu fault zone is considered to be related to high speed highly oblique subduction of the pacific plate at this time

mesozoic metallogeny in east china and corresponding geodynamic settings an introduction to the special issue abstract the giant east china mesozoic metallogenic province hosts some of the world s largest resources of tungsten tin molybdenum antimony and bismuth ores of gold silver mercury lead zinc copper uranium and iron are also of major importance the province and its constituent metallogenic belts or regions south china middle lower yangtze river valley east qinling dabie interior of north china craton yan liao and north east china are the products of several pulses of igneous activity and mineralisation between 240 and 80 ma each successive stage has produced a distinctive suite of deposits that can be readily related to the geodynamic evolution of the region during the mesozoic this geodynamic evolution is linked to a complex series of tectonic events involving far field subduction plate collisions crustal thickening post collision collapse and rifting

geochronology and geochemistry of the giant qian echong mo deposit dabie shan eastern china implications for ore genesis and tectonic setting abstract the qian echong mo deposit is a giant porphyry deposit in the dabie shan of eastern china molybdenum mo mineralization mainly occurs as numerous veinlets in altered schists with the development of potassic phyllic argillic and propylitic alteration assemblages a buried granite porphyry stock and locally exposed dikes are spatially and genetically related to the mo mineralization zircon crystals from exposed quartz porphyry rhyolitic porphyry and granite porphyry dikes as well as a buried granite porphyry dike yield weighted average 206 pb 238 u ages of 128 9 1 1 ma mswd 0 30 2 n 13 127 42 0 94 ma mswd 0 58 2 n 17 127 44 0 98 ma mswd 1 6 2 n 16 and 126 6 1 4 ma mswd 0 67 2 n 15 respectively the buried granite porphyry stock yields a zircon u pb weighted average age of 124 7 1 6 ma mswd 1 5 2 n 16 which is slightly younger than the exposed dikes but within error of the age of the buried granite porphyry dike five molybdenite samples from the ores yield re os isotope ages of 123 31 1 02 to 128 49 1 40 ma which are consistent with the u pb ages for the igneous rocks these age data constrain magmatic hydrothermal activity at the qian echong mo deposit to a period of about six million years from 129 to 123 ma this period overlaps the recognized regional mo mineralization event in the dabie shan of 142 111 ma which took place during the post collisional tectonism subsequent to amalgamation of the yangtze and north china blocks the qian echong granite porphyry stock and dikes have high contents of sio 2 k 2 o and al 2 o 3 and low contents of tio 2 mgo and cao showing a peraluminous high k calc alkaline to shoshonite affinity with obvious lree enrichment and a negative eu anomaly the rocks have a high initial 87 sr 86 sr of 0 70729 to 0 71788 and highly negative e nd t values of 16 2 to 26 1 with t dm2 nd ages of 2 24 to 3 03 ga their 206 pb 204 pb t 207 pb 204 pb t and 208 pb 204 pb t values range from 16 017 to 16 701 15 252 to 15 368 and 37 095 to 37 578 respectively this sr nd pb isotopic signature indicates that the causative granitic intrusions for the qian echong deposit were mainly melts with components of both the northern dabie complex and the taihua and xiong er groups that are part of the precambrian basement of the north china block the melts were generated during the tectonic extrusion of the dabie shan and their emplacement onto the basement of the north china block the qian echong mo deposit is unique based upon the crustal source for the causative porphyry localization of most mineralization in the surrounding schist country rocks and the co 2 rich ore forming fluid thus we propose the qian echong deposit to represent a new sub type of porphyry mo deposit herein termed collisional or dabie type porphyry deposit

processes and rate of retreat of the clay and sandstone sea cliffs of the northern boulonnais france abstract retreat of the clay and sandstone cliffs of the northern boulonnais france has been quantified using stereophotogrammetry the low retreat rate of this coastal strip 0 08 m yr between 1939 and 2003 is far less than that encountered on chalk and clay chalk cliffs of either side of the channel and even less than a previous estimate of 0 17 m yr regularly quoted in management studies the retreat rate is closely related to shore platform morphology and dynamics the shore platform presents 1 a steeply sloping ramp due to the accumulation of flat calcareous megaclasts that reduce marine erosion 2 upstanding bare platform surfaces related to tectonic deformation and 3 thick platform beaches trapped in troughs in all three cases the reflective behaviour of the nearshore protects the cliff foot from the incoming waves two critical eroding segments are the result of changes in the platform sedimentary budget around cran poulet and between plage de la sirene and pointe de la courte dune the retreat rate is up to 0 25 and 0 15 m yr respectively at cran poulet recession has been facilitated by the extraction of pebble for more than half a century whereas erosion of the beach at la sirene is probably linked to severe erosion of the coastline in the adjacent wissant bay mass movements on the cliff face are essentially shallow seated translational slides along with small debris falls and mudflows the instability of the argiles de ch tillon is greatly diminished by their sandy and silty texture and by the presence of interstratified solid shelly limestone beds that allow steep slopes to develop in rather weak material the vertical erosion antecedent is the erosional mode of the cliff and its reduced efficiency explains the slow recession of the cliff this study will help to determine the long term evolution of the boulonnais coast

re os isotopic ages of tangjiaping molybdenum deposit in shangcheng county henan and their geological significance in order to determine the age of the tangjiaping large size molybdenum deposit in shangcheng county and establish the metallogenic model for molybdenum polymetallic ore deposits the authors dated seven molybdenite samples from tangjiaping and two other molybdenum deposits by using such ionic mass spectrographs as inductance coupling the results show that the re os isochron age of molybdenite from the tangjiaping molybdenum deposit is 113 1 7 9 ma suggesting early cretaceous the re os isotopic model age of molybdenite from the tianmugou molybdenite is 121 6 2 1 ma and the re os isotopic model age of molybdenite from the dayinjian molybdenum is 122 1 2 4 ma it is thus thought that the ore forming age of the dabie molybedum metallogenic belt should be 122 1 2 4 113 1 7 9 ma considering also the achievements made by previous workers the authors hold that the molybdenum metallogenic geodynamic background of the northern slope of the dabie mountain should be a great transformation period during which the lithosphere of the dabie orogenic belt became thinner under the stretching mechanism and the regional tectonic dynamic system of central and eastern china turned from nearly ew trending to nearly sn trending structures

coupled substitutions involving rees and na and si in apatites in alkaline rocks from the ilimaussaq intrusion south greenland and the petrological implications ansrnlcr apatites from the ilimaussaq augite syenite the sodalite foyaite and a qtartz bearing peralkaline pegmatite have been analyzed using an electron microprobe for the major elements plus na si and selected rare earth elements rees in all three rock types the maximum reeto3 content in the apatite exceeds 16 0 wt0 0 apatite from the augite syenite and primary apatite from the sodalite foyaite are characterizedby a low na content that varies independently of the ree content the composition of these apatites approaches 25 molo o of the end member carreq sio4 3 oh f cl lessingite in response to the substitution ree3 sia ca2 ps ree and na enriched apatites from the quartzbearing peralkaline pegmatite are almost si free and rees and na are positively correlated the composition of these apatites approaches 25 molo o of the hypothetical endmember na5ree5 po4 6 oh f ci 2 in response to the substitution na ree3 2ca2 the compositional trend of late crystalllzing apatite from the sodalite foyaite reflects almost equal contributions of the two substitutions the relationship between these substitutions in a given apatite and its associated mineral assemblage indicates that the na component is only present in considerable amounts when apatite crystallizes in a strongly peralkaline environment

geochemical age and isotopic constraints on the location of the sino korean yangtze suture and evolution of the northern dabie complex east central china the northern dabie complex in east central china lies between the sino korean plate to the north and the yangtze plate to the south the northern dabie complex has been variously proposed to represent a paleozoic magmatic arc on the sino korean plate an exhumed piece of subducted yangtze plate crust or crust produced almost entirely by cretaceous extension related magmatism trace element compositions of northern dabie complex orthogneisses and granites show arc signatures similar to those of ultra high pressure rocks in the central dabie but no mineralogical evidence of ultra high pressure metamorphism is present in the samples investigated here field relationships textures major and trace element compositions and ion microprobe u pb zircon protolith crystallization ages reveal three distinct types of gneiss diorite gneiss xenoliths 770 6 26 ma 95 confidence limit those within first genation highly deformed migmatitic grey gneisses 747 6 14 ma and those cross cut by secondgeneration cretaceous weakly foliated felsic gneisses 127 6 4 ma unfoliated cretaceous granites 117 6 11 ma monazite th pb age 5 117 6 1 ma intrude secondgeneration gneisses cretaceous second corresponding author e mail john c ayers vanderbilt edu generation gneisses and granites yield zircon inheritance ages of ca 2 ga 700 800 ma and rarely 227 271 ma indicating that the northern dabie complex is not simply a cretaceous extensional terrane the 700 800 ma zircon ages are similar to those of granitic gneisses from the central ultra highpressure zone 698 6 47 ma and are characteristic of the yangtze craton nd values suggest that cretaceous rocks in the northern dabie complex formed by partial melting of basement with very low nd and not by melting of first generation or diorite gneisses nd depleted mantle model ages are consistent with the time of formation of the yangtze craton at 1 4 2 5 ga the northern dabie complex is interpreted to be an extension of the yangtze craton that was unaffected by ultra high pressure metamorphism the sino korean yangtze suture must lie to the north of the northern dabie complex

timing and processes of late mesozoic mid lower crustal extension in continental ne asia and implications for the tectonic setting of the destruction of the north china craton mainly constrained by zircon u pb ages from metamorphic core complexes abstract late mesozoic large scale crustal extension occurred across the northeastern section of continental asia and metamorphic core complexes mccs are the major features in this region this paper presents new zircon u pb and ar ar ages of biotite and hornblende for pre or syn mylonitized and post kinematic unmylonitized intrusions from these mccs and attempts to determine the timing of initiation duration and termination of the mid lower crustal ductile extension by integrating with geochronological data from previous studies these mccs have similar 40 ar 39 ar biotite and hornblende ages 130 to 110 ma mainly from 130 to 120 ma which are interpreted as the cooling ages and represent the timing of the late stage formation of the mccs zircon u pb ages for syn to post kinematic intrusions from some mccs suggest that the mid lower crustal extension probably initiated at ca 150 145 ma with a peak occurring 145 130 ma and continued to 130 120 ma which is older than that suggested by 40 ar 39 ar ages by 10 20 ma the early ductile extension most likely initiated in mongolia and northern china during the late jurassic 150 145 ma at a deeper level then propagated southwards 140 130 ma and finally developed throughout the entire continental ne asia 130 120 ma based on the timing and processes of the extension a geodynamic model and tectonic setting of the destruction of the north china craton ncc are proposed

regional metallogeny of mo bearing deposits in northeastern china with new re os dates of porphyry mo deposits in the northern xilamulun district with many new discoveries of giant mo deposits in the past decade northeastern china has become the largest molybdenum mineralization region in china the xilamulun district is in the southern part of northeastern china and contains 25 mo deposits and prospects dominantly of porphyry type these deposits are mostly along the e striking xilamulun fault re os dating of hydrothermal molybdenite from four deposits in the northern xilamulun district revealed mineralization ages of 137 to 129 ma 129 4 3 4 ma for aolunhua 135 3 2 6 ma for shabutai 136 4 0 8 ma for haisugou and 136 1 6 6 ma for banlashan in general agreement with the crystallization ages of their host granitoids the compilation of existing data on mo bearing deposits in northeastern china including the new data of this study shows that mesozoic mo deposits in this region have a wide range of ages from 250 to 90 ma we propose that they are linked to three tectonic magmatic events 1 triassic mo deposits 250 220 ma are mainly distributed along the e trending xilamulun fault and are related to postcollisional crustal extension following the final closure of the paleo asian ocean 2 jurassic mo mineralization 200 140 ma displays a clear younging trend from southeast to northwest coincides with the regional magmatism trend and is interpreted to be related to the northwestward flat slab subduction of the paleo pacific plate beneath the eurasian continent that started in the early jurassic ca 200 ma 3 cretaceous mo mineralization 140 90 ma shows a reversed migration trend from northwest to southeast and can be explained by the coastward migration of slab rollback related to lower crust delamination asthenospheric upwelling and lithospheric thinning in eastern china the spatial temporal distribution of mesozoic mo mineralization is important for regional metallogeny and exploration recently numerous epithermal au cu mo deposits have been recognized in the southeast margin of northeastern china according to this study we predict that hidden porphyry skarn systems could be located beneath these epithermal deposits

early cretaceous granitoids and their implications for the collapse of the dabie orogen eastern china shrimp zircon u pb dating and geochemistry abstract two stages of early cretaceous post orogenic granitoids are recognized in the dabie orogen eastern china which recorded processes of extensional collapse of the orogen the early stage granitoids 132 ma are foliated hornblende quartz monzonites and porphyritic monzogranites they are of high k calc alkaline series and metaluminous to weakly peraluminous with high k 2 o and low mgo contents mg values 32 0 46 0 they contain high sr low y and heavy rare earth elements hree and have high sr y and la yb n ratios without clear negative eu sr and ti anomalies the early stage deformed granitoids have adakitic geochemical compositions and are equilibrated with residues rich in garnet and poor in anorthite rich plagioclase and thus indicate the existence of an over thickened 50 km crustal root beneath the orogen at 132 ma the later stage granitoids 128 ma are undeformed fine grained monzogranites fine grained k feldspar granites and coarse grained k feldspar granite porphyry they belong to a peraluminous and high k calc alkaline to shoshonite series and display a flat hree pattern and have strong negative eu sr and ti anomalies with low sr y and la yb n ratios the late stage granitoids are equilibrated with residues rich in anorthite rich plagioclase hornblende ilmenite titanite and poor in garnet indicating that the crust of the dabie orogen became thinner

utilizing dems derived from lidar data to analyze morphologic change in the north carolina coastline by using digital elevation model dem data derived from light detection and ranging lidar data an approximately 70 km stretch of the southern north carolina coastline was studied the coastline consists of five barrier islands located between masonboro island at the southern extent and topsail island at the northern extent the high resolution dem data allowed for a comprehensive visual quantitative investigation into the spatial patterns of morphologic change that occurred to the barrier islands oceanfront beaches between 1997 and 2000 this study also demonstrated the usefulness of using laser altimetry to examine barrier islands response to level of tropical activity and showed that the coastal process of overwash was recognized as an integral component of barrier island landward migration means of net volumetric change per unit area m 3 m 2 for study areas of different beach management practices characterized as developed undeveloped and nourished beaches on a yearly basis for the period between 1997 and 2000 were derived t test of the means has been conducted and results showed that beaches differed statistically if different management practices were applied to them and the differences were minimized or disappeared if sequential hurricanes or storms affected the beaches d 2002 elsevier science inc all rights reserved

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

assessing regional geodiversity the iberian peninsula geodiversity is a landscape characteristic related to the heterogeneity of the physical properties of the earth surface in this work we quantify and compare geodiversity in several geodynamic zones of the iberian peninsula for this purpose we have developed a geographic information system gis procedure to carry out a regional terrain classification based on geodiversity factors a classification process helped to produce a morphometric map 10 classes a morphoclimatic map five classes and a geological map 15 classes these three maps were combined using an overlay operation union to obtain the final terrain classification 419 classes which was then applied to calculate diversity landscape indices the latter were calculated using common landscape diversity indices patch richness density shannon s diversity index shannon s evenness index simpson s diversity index and simpson s evenness index provided by fragstats free software these indices were calculated for the whole landscape of the main iberian geological regions thus revealing a close relationship between some index values and the geological and geomorphological characteristics the highest diversity values are associated with alpine collisional orogens and reactivated chains of the precambrian palaeozoic massif intraplate orogen with sedimentary cover characterized by extensive planation surfaces have lower values mesozoic areas with no significant tectonic deformation and cenozoic basins are characterized by the lowest diversity values amongst the latter the major diversity is associated with the most dissected basins which also present higher morphoclimatic variety though depending on the chosen scale and the landscape classification criteria these indices provide an objective assessment of the regional geodiversity of iberia copyright 2009 john wiley sons ltd

geochemistry of zircon and apatite from the mo ore forming granites in the dabie mo belt east china implications for petrogenesis and mineralization abstract the dabie molybdenum mo belt in east china is an important mo belt in both china and the world all of the mo deposits in the dabie area are porphyry skarn type the ore related granite samples from the qian echong tangjiaping and doupo mo deposits in the mo belt have been collected for zircon and apatite trace elements analysis additionally the doupo ore related granite has also been chosen for zircon u pb dating la icp ms zircon u pb dating of the ore related granite in the doupo mo deposit yields a crystallization age of 127 1 ma which is consistent with the molybdenite re os age of the deposit the chondrite normalized patterns of all zircons are characterized by positive ce anomalies with variable negative eu anomalies the ore related granites in the qian echong and tangjiaping mo deposits show relatively high magmatic oxygen fugacity fmq 1 5 whereas the doupo ore related granite has a relatively low magmatic oxygen fugacity fmq 0 3 which might have caused it to have relatively small mo reserve compared to the qian echong and tangjiaping deposits all of the apatites from the three mo deposits are characterized by lree enriched and hree depleted chondrite normalized patterns with various degrees of eu depletion and ce enrichment not only redox condition but also other factors could have influenced the eu eu or and ce ce of apatite in this study and the anomalies of eu and ce of apatites from the ore related granites in this study could not be used to evaluate the magma redox states the geochemical characteristics of apatite indicate that the ore forming magmas of the mo deposits in this study are oxidized and metaluminous i or a type magmas during the early cretaceous regional extension and asthenospheric upwelling in the dabie orogen partial melting of the crustal rocks generated oxidized mo bearing magma relatively oxidized condition prevents mo from incorporating into sulfides or silicates in the magma and finally leads to mo precipitation from the ore forming fluids which released from the magma

tectonics of the qinling central china tectonostratigraphy geochronology and deformation history abstract the qinling orogen preserves a record of late mid proterozoic to cenozoic tectonism in central china high pressure metamorphism and ophiolite emplacement songshugou ophiolite assembled the yangtze craton including the lower qinling unit into rodinia during the 1 0 ga grenvillian orogeny the lower qinling unit then rifted from the yangtze craton at 0 7 ga subsequent intra oceanic arc formation at 470 490 ma was followed by accretion of the lower qinling unit first to the intra oceanic arc and then to the sino korea craton subduction then imprinted a 400 ma andean type magmatic arc onto all units north of the northern liuling unit oblique subduction created silurian devonian wnw trending sinistral transpressive wrench zones e g lo nan shang dan and late permian early triassic subduction reactivated them in dextral transpression lo nan shang xiang shang dan and subducted the northern edge of the yangtze craton exhumation of the cratonal edge formed the wudang metamorphic core complex during dominantly pure shear crustal extension at 230 235 ma post collisional south directed shortening continued through the early jurassic cretaceous reactivation of the qinling orogen started with nw se sinistral transtension coeval with large scale early cretaceous crustal extension and sinistral transtension in the northern dabie shan it presumably resulted from the combined effects of the siberia mongolia sino korean and lhasa west burma qiangtang indochina collisions and pacific subduction regional dextral wrenching was active within a ne sw extensional regime between 60 and 100 ma an early cretaceous andean type continental magmatic arc with widespread early cretaceous magmatism and back arc extension was overprinted by shortening related to the collision of yangtze indochina block with the west philippines block strike slip and normal faults associated with eocene half graben basins record paleogene nne ssw contraction and wnw ese extension the neogene is characterized by normal faults and nne trending sub horizontal extension pleistocene quaternary nw se extension and ne sw contraction comprises sinistral strike slip faults and is part of the nw se extension imposed across eastern asia by the india asia collision

u pb zircon ages constrain the architecture of the ultrahigh pressure qinling dabie orogen china new shrimp and tims zircon ages 40ar 39ar ages and eclogite locations contribute significantly to our understanding of the ultrahigh pressure dabie shan 1 the geographic extent of the yangtze craton that was subducted to ultrahigh pressure extends to the northern edge of the dabie shan 2 the northern half of the dabie shan is a magmatic complex intruded over a 10 myr interval between 137 and 126 ma that accommodated 100 n s stretching of the pre existing collisional architecture 3 granitic orthogneisses and enclosing ultrahigh pressure paragneisses have indistinguishable zircon populations the population of triassic zircon ages ranges from 219 to 245 ma leading us to question the prevailing assumption that 219 ma zircons formed at ultrahigh pressure and to propose instead that they reflect late retrogression at crustal pressures following the bulk of exhumation

zircon trace elements and magma fertility insights from porphyry skarn mo deposits in ne china it has been widely accepted that magmas genetically linked to porphyry skarn cu mo deposits are commonly oxidized recently using laser ablation inductively coupled plasma mass spectrometry la icp ms techniques zircon ce4 ce3 cen cen eun eun and ce nd ratios and magma fmq values departure from the fayalite magnetite quartz oxygen buffer based on zircon trace element compositions have been used as proxies to quantify magma oxidation state here we present the zircon trace element compositions of 13 mesozoic porphyry skarn mo deposits in ne china of various sizes to examine the relationship between magma mo fertility and magma oxidation state generally the studied deposits with 0 3 mt mo have ce4 ce3 100 cen cen 100 ce nd 10 and eun eun 0 3 whereas those containing 10 mt cu the findings in this study can be used to evaluate an intrusion s potential to produce mo mineralization

copper enrichment in arc magmas controlled by overriding plate thickness the characteristics of magmas typically associated with porphyry copper deposits are thought to be imparted in the mantle statistical assessment of over 40 000 geochemical analyses of magmatic rocks formed in subduction zones worldwide however shows that the characteristics of these magmatic rocks are systematically controlled by the thickness of the arc crust

giant porphyry deposits characteristics distribution and tectonic controls more than half of the 25 largest known porphyry copper deposits defined in terms of contained copper metal formed during three time periods the paleocene to eocene eocene to oligocene and middle miocene to pliocene these giant deposits are clustered within three provinces central chile northern chile and southwest arizona northern mexico other giant deposits occur in montana utah panama peru argentina irian jaya mongolia and iran compressive tectonic environments thickened continental crust and active uplift and erosion were associated with the formation of many of these deposits calc alkalic magmas are most favorable for the formation of giant porphyry copper deposits although several of the largest systems are associated with high k calc alkalic intrusions the 25 largest gold rich porphyry deposits are concentrated in the southwest pacific and south america with other occurrences in eurasia british columbia alaska and new south wales many of the deposits formed in the last 13 m y the largest of the deposits are associated with high k calc alkalic intrusions many calc alkalic porphyritic intrusions have also produced giant gold rich porphyries in the last 20 m y the formation of giant porphyry copper molybdenum and copper gold deposits in the circum pacific region has been closely associated with subduction of aseismic ridges seamount chains and oceanic plateaus beneath oceanic island and continental arcs in several examples these tectonic perturbations have promoted flat slab subduction crustal thickening uplift and erosion and adakitic magmatism coeval with the formation of well endowed porphyry and or epithermal mineral provinces similar tectonic features are inferred to be associated with the giant porphyry copper molybdenum provinces of northern chile eocene oligocene and southwest united states cretaceous paleocene topographic and thermal anomalies on the downgoing slab appear to act as tectonic triggers for porphyry ore formation other factors such as sutures in the overriding plate permeability architecture of the upper crust efficient processes of ore transport and deposition and in some cases formation and preservation of supergene enrichment blankets are also vital for the development of high grade giant ore deposits a low grade geochemical anomaly may be the final product of mineralization if ore forming processes do not operate efficiently even in the most favorable geodynamic settings

trace element partitioning between apatite and silicate melts we present new experimental apatite melt trace element partition coefficients for a large number of trace elements cs rb ba la ce pr sm gd lu y sr zr hf nb ta u pb and th the experiments were conducted at pressures of 1 0 gpa and temperatures of 1250 c the rare earth elements la ce pr sm gd and lu y and sr are compatible in apatite whereas the larger lithophile elements cs rb and ba are strongly incompatible other trace elements such as u th and pb have partition coefficients close to unity

geomorphic and human influence on large scale coastal change abstract an increasing need exists for regional scale measurements of shoreline change to aid in management and planning decisions over a broad portion of the coast and to inform assessments of coastal vulnerabilities and hazards a recent dataset of regional shoreline change covering a large portion of the u s east coast new england and mid atlantic provides rates of shoreline change over historical 150 years and recent 25 30 years time periods making it ideal for a broad assessment of the regional variation of shoreline change and the natural and human induced influences on coastal behavior the variable coastal landforms of the region provide an opportunity to investigate how specific geomorphic landforms relate to the spatial variability of shoreline change in addition to natural influences on the rates of change we examine the effects that development and human modifications to the coastline have on the measurements of regional shoreline change regional variation in the rates of shoreline change is a function of the dominant type and distribution of coastal landform as well as the relative amount of human development our results indicate that geomorphology has measurable influence on shoreline change rates anthropogenic impacts are found to be greater along the more densely developed and modified portion of the coast where jetties at engineered inlets impound large volumes of sediment resulting in extreme but discrete progradation updrift of jetties this produces a shift in averaged values of rates that may mask the natural long term record additionally a strong correlation is found to exist between rates of shoreline change and relative level of human development using a geomorphic characterization of the types of coastal landform as a guide for expected relative rates of change we found that the shoreline appears to be changing naturally only along sparsely developed coasts even modest amounts of development influence the rates of change and the human imprint override the geomorphic signal the study demonstrates that human activities associated with creating and maintaining coastal infrastructure alter the natural behavior of the coast over hundreds of kilometers and time spans greater than a century this suggests that future assessments of vulnerability based largely on rates of change along developed coastlines need to take the role of human alterations into account

a tectono genetic model for porphyry skarn stratabound cu au mo fe and magnetite apatite deposits along the middle lower yangtze river valley eastern china abstract the middle lower yangtze river valley metallogenic belt yrb situated along the northern margin of the yangtze craton is characterized by porphyry skarn stratabound cu au mo fe deposits in the areas of uplift and magnetite apatite deposits in cretaceous fault basins following detailed field investigations and a review of published data we recognize two episodes of magmatism and mineralization in the yrb 1 156 137 ma high k calc alkaline granitoids associated with 148 135 ma porphyry skarn stratabound cu au mo fe deposits and 2 135 123 ma shoshonitic series associated with 134 9 122 9 ma magnetite apatite deposits a type granitoids and associated alkaline volcanic have a small age range from 126 5 to 124 8 ma and are temporally spatially and genetically associated with the second episode the geodynamic history of the yrb did not experience the paleozoic to mesozoic lithospheric thickening that took place in the north china craton this process is inferred to be linked to partial melting of the delaminated lower crust at high pressures resulting in the development of c type adakitic rocks the petrochemical and sr nd isotopic data show that both the shoshonitic series and a type granitoids are quite different from adakites with only some of the k calc alkaline granitoids having adakitic signatures previous ore genesis models were established based on an assumed relationship with adakites and a continuous tectono thermal evolution from 150 to 100 ma all data obtained for the middle lower yangtze river region consistently show that the tan lu regional strike slip fault zone initiated at 233 6 to 225 6 ma from the collision between the north china and yangtze cratons and was reactivated at ca 160 ma the tan lu fault was caused by the oblique subduction of the izanagi plate which along the yrb the low angle subducted slab and the overlying crust was disrupted or broken due to the disharmonious movement of the two blocks the high k calc alkaline granitoids magmas were derived from melting of the subducted slab with some input of crustal material these magmas were emplaced at the intersections between ne and ew trending faults and formed porphyry skarn stratabound cu au mo fe deposits between 156 and 137 ma after 135 ma the subducted plate changed its direction of motion to northeast now running parallel to the eurasian continental margin and leading to large scale continental extension the shoshonitic series and subsequent a type granitoids magmatism and the development of magnetite apatite ores in the yrb took place in both fault basins and ne trending rifts between 135 and 124 ma

rock coast geomorphology recent advances and future research directions there have been considerable advances in rock coast research in the past decade as measured in terms of the number of active researchers and in the number of research papers being produced this review although not exhaustive highlights many of the improvements that have been made in our ability to identify and measure the processes shaping rock coasts at a range of spatial and temporal scales we review how researchers are experimenting with new techniques grappling with quantifying the effects of multiple processes on resultant landforms and exploring how well rock coast systems relate to wider geomorphological and earth science debates recent research including those in this special issue aptly demonstrate the scientific benefits that can be accrued by studying rock coasts at a variety of spatial and temporal scales by considering the effect of the wide range of processes that operate on them and by the application of new measurement techniques and approaches despite these advances there is ample scope for future research which could profit from increasing collaboration with other coastal geomorphologists and allied earth science disciplines in order to identify and quantify linkages between rock coasts and other coastal systems it is also important that new research considers how rock coasts will respond to extreme events and to risks associated with changing climate and to how rock coast geomorphology might contribute beyond coastal science to wider debates in theoretical geomorphology

coastline change of the yellow river estuary and its response to the sediment and runoff 1976 2005 abstract the dramatic decreases in runoff and sediment have great impacts on erosion deposition variation in the yellow river estuary this study extracted mean high tide lines of the yellow river estuary from mss tm and etm data from 1976 to 2005 and explored relationships between the accretion erosion of land and the runoff and sediment load of the yellow river the results showed that the general pattern of accretion erosion of the entire estuary was divided into four stages rapid accretion stage 1976 1986 accretion erosion adjustment stage 1986 1996 slow erosion stage 1996 2003 and slow accretion stage 2003 present for maintaining the annual balance of the entire estuary 1976 2005 and q8 estuary most recent course of the qingshuigou estuary from 1996 to 2005 critical annual runoff and sediment load are 140 36 108 m3 year 1 and 3 31 108 t year 1 and 85 0 108 m3 year 1 and 1 63 108 t year 1 respectively in the future decades the q8 estuary is likely to maintain its shape and area balance or have a little accretion but the entire estuary could be in an eroding state

mesozoic molybdenum deposits in the east qinling dabie orogenic belt characteristics and tectonic settings abstract the east qinling dabie orogenic belt accommodates the largest mo ore district in the world it contains 8 43 mt of proven mo metal reserves which accounts for 66 of the total proven chinese mo reserves the mo ore district includes 24 deposits and 12 occurrences with four major types of mo mineral systems i e porphyry porphyry skarn skarn and hydrothermal veins the latter can be further subdivided into quartz vein and carbonatite vein types although mo mineralization in the belt began in the paleoproterozoic 1680 24 to 2044 14 ma all economically significant deposits were formed during the mesozoic re os dating of molybdenite has shown that there are three episodes of mo mineralization i e late triassic 233 221 ma late jurassic to early cretaceous 148 138 ma and early to middle cretaceous 131 112 ma late triassic mo deposits developed as molybdenite quartz veins and carbonatite vein types stable isotope systematics c o s and high contents of re and sr indicate that the carbonatite mo veins are mantle derived porphyry and porphyry skarn mo mineral deposits were formed in the late jurassic to early cretaceous and early to middle cretaceous the late jurassic to early cretaceous granite porphyries that are associated with the mo deposits usually occupy less than 1 5 km2 at the surface and are situated in the east qinling area far west of china s continental margin on the other hand the early to middle cretaceous batholiths and granite porphyries with associated mo deposits are located in the dabieshan area and eastern part of the east qinling area the late jurassic to early creataceous granitoids and related mo deposits possibly formed in a back arc extensional setting of the eurasian continental margin which was probably triggered by the oblique subduction of the izanagi plate the early to middle cretaceous batholiths and granite porphyries are linked to the tectonic regime of lithospheric thinning asthenospheric upwelling and partial melting of the crust induced by a change in izanagi plate motion parallel to the continent margin in the east qinling dabie belt there are vein type pb zn ag deposits surrounding porphyry and or porphyry skarn mo w deposits forming well defined ore clusters the same spatial arrangement i e porphyry mo stockworks and outlying pb zn ag ore veins is also observed at the deposit scale thus mo porphyry stockworks and distal polymetallic veins belong to the same ore system and may reflect an outward temperature decrease from the highly fractionated granite plutons both porphyry stockworks and polymetallic veins can be used as vectors for further prospecting

petrogenesis of mesozoic granitoids in the dabie uhp complex central china trace element and nd sr isotope evidence post collisional magmatism in the dabie orogen is characterized by the near contemporaneous intrusion of voluminous granitoids and minor mafic magmas in the late mesozoic 135 110 ma the granitoids are represented by three major batholiths in northern dabie zhubuyuan baimajian and tiantangzhai the largest zhubuyuan batholith comprises hornblende bearing intermediate rocks penghe suite and hornblende free granitic rocks huangbai suite the huangbai granites show limited variation in chemical composition but are highly variable in textures ranging from medium to coarse grained they have rather homogeneous sr and nd isotopic compositions with 87sr 86sr i 0 708 0 709 and end t 19 to 24 the penghe intermediate suite covers a wide spectrum of rock types including diorite monzodiorite quartz monzonite to monzogranitic rocks and all of them contain hornblende and mafic enclaves the existence of compositional and textural disequilibrium e g calcic and resorbed cores of plagioclase and the nature of chemical variation in these rock types indicate that magma mixing between an evolved mafic and a granitic magma was involved in their genesis fractional crystallization fc could have coupled with the process of magma mixing but with minor contamination by the upper continental crust during magma ascent isotopically the intermediate rocks show a variation in end t values from 13 7 to 18 while their 87sr 86sr i ratios vary from 0 7074 to 0 7088 the genesis and evolution of the dabie post collisional magmatic rocks may be summarized as follows intrusion of mantle derived mafic ultramafic magmas into thickened continental crust induced dehydration melting of the lower crust rocks with intermediate compositions and subsequent production of large amounts of granitic melts huangbai suite extensive interaction between the crustal and mantle derived melts through mixing produced a hybrid parental magma which subsequently underwent a fc process en route to higher crustal levels producing a wide variety of rock types as shown by the penghe intermediate rock suite injection of successive pulses of basic magma into upward mobile magma chambers could have resulted in the formation of the mafic enclaves as well as mafic dykes

human impacts quantification on the coastal landforms of gran canaria island canary islands abstract the coastal areas of the canary islands are particularly sensitive to changes both from a natural perspective and for their potential socio economic implications in this paper the state of conservation of an insular coast is approached from a geomorphological point of view considering recent changes induced by urban and tourism development the analysis is applied to the coast of gran canaria a small atlantic island of volcanic origin subject to a high degree of human pressure on its coastal areas especially in recent decades currently much of the economic activity of gran canaria is linked to mass tourism associated with climatic and geomorphological features of the coast this work is addressed through detailed mapping of coastal landforms across the island 256 km perimeter corresponding to the period before the urban and tourism development late 19th century for the island s capital mid 20th century for the rest of the island and today the comparison between the coastal geomorphology before and after the urban and tourism development was established through four categories of human impacts related to their conservation state unaltered altered semi destroyed and extinct the results indicate that 43 of coastal landforms have been affected by human impacts while 57 remain unaltered the most affected are sedimentary landforms namely coastal dunes palaeo dunes beaches and wetlands geodiversity loss was also evaluated by applying two diversity indices the coastal geodiversity loss by total or partial destruction of landforms is estimated at 15 2 according to shannon index h while it increases to 32 1 according to an index proposed in this paper we conclude that the transformations of the coast of gran canaria induced by urban and tourism development have heavily affected the most singular coastal landforms dunes palaeo dunes and wetlands reducing significantly its geodiversity

a review of the geological characteristics and geodynamic setting of the late early cretaceous molybdenum deposits in the east qinling dabie molybdenum belt east china abstract the east qinling dabie molybdenum belt which is located in the nearly east west trending qinling dabie orogen east china is the largest mo belt in the world and is characterized by extensive mesozoic mineralization although the late early cretaceous ca 120 100 ma is the latest stage of the mo mineralization in the east qinling dabie mo belt this period shows relatively intensive mo mineralization such as the world class shapinggou mo deposit all of the late early cretaceous mo deposits are closely related to granitic magmatism some of which are typical porphyry type deposits e g donggou tangjiaping shapinggou homogenization temperatures of fluid inclusions in the late early cretaceous mo deposits range from 115 to 550 c with salinities ranging from 0 02 to 62 1 wt nacl equivalent different amount of co2 have been recognized in the hydrothermal systems of these mo deposits indicating h2o nacl co2 systems the ore forming fluids in these mo deposits were magmatic water mixed with different amount of meteoric water except the donggou deposit the 34s values of sulfides from the late early cretaceous mo deposits have a narrow range of 0 4 6 3 suggesting a deep magmatic source for the sulfur the donggou mo deposit has slightly higher 34s values 7 5 9 4 reflecting that the ore sulfur was mainly derived from magma probably with some upper crust materials available isotopic data show that the ore associated magmas of the late early cretaceous mo deposits were mainly derived from crustal materials probably with some contribution of mantle or newly added crust the donggou tangjiaping and shapinggou mo deposits are genetically related to a type magmatism suggesting that they formed in an extensional setting the late early cretaceous mo deposits in the east qinling dabie mo belt formed in an intraplate extensional setting accompanied by the lithospheric thinning and asthenospheric upwelling

the mo deposits of northeast china a powerful indicator of tectonic settings and associated evolutionary trends abstract northeast ne china lies in the eastern sector of the central asian orogenic belt caob that connects with the circum pacific orogenic belt in the east and accommodates multistage magmatism crustal growth and mineralization in this region 69 mo only or mo dominated and 9 cu mo deposits have been discovered including 65 deposits ranking medium size 10 kt mo metal or larger in tonnage and containing a total resource of 10 5 mt mo metal six giant and seventeen large deposits have total reserves of 6 7 and 3 1 mt mo respectively these deposits occur in the areas surrounding the songliao basin including the northern margin of the north china craton the great hingan range and the ji hei fold belt and have been formed during paleozoic and mesozoic tectono magmatic events all the mo only or mo dominated deposits were formed in the mesozoic postdating the closure of the paleo asia ocean and in a series of pulses around 250 200 ma 200 160 ma 160 130 and

temporal and spatial variations of chalk cliff retreat in east sussex 1873 to 2001 spatial and temporal variations of chalk cliff retreat rates over a 130 yr period are examined for 22 km of the east sussex chalk coastline between brighton and belle toutetout lighthouse england data are derived from maps surveyed between 1873 and 1925 28 and air photographs dating from 1973 and 2001 the long term average cliff retreat rate over the period 1873 to 1973 is 0 36 m y 1 and from 1873 to 2001 is 0 35 m y 1 over the whole 23 km study area rates calculated over shorter time slices indicate a decline in cliff retreat 0 37 m y 1 between 1873 and 1925 28 0 35 m y 1 between 1925 28 and 1973 0 27 m y 1between 1973 and 2001 temporal variations are unlikely to be due to variations in precipitation and frost days though the relationship remains uncertain due to the resolution of available cliff retreat and climatic data changes in wave climate are small and cannot be responsible for the decline in cliff retreat the study suggests that the most important factors causing the measured decline in cliff retreat rates are firstly the loss of cliff toe beaches over time and secondly widening of the rocky shore platforms that front the cliffs some of the spatial variability in retreat rates can be explained by local variations in lithology

the geochemistry of phosphorus in different granite suites of the western carpathians slovakia the role of apatite and p bearing feldspar the geochemical behaviour of phosphorus in granites coupled with compositional variations in apatite discriminate the different genetic suites of variscan granitic rocks in the west carpathian orogenic belt meso variscan granites mostly of stype affinity show a good correlation between sio2 and p2o5 with decreasing amounts of p in the poorly and moderated fractionated granites and increasing phosphorus in the most evolved and late differentiation products the aluminium saturation index asi correlates negatively with bulk p contents in i type granites and positively with p in s type granites the phosphorus content of alkali feldspar mainly kfs is usually very low typically 0 05 wt p2o5 or not detected in the slightly differentiated granites in the latevariscan i s type granitoids phosphorus is hosted mainly in the early magmatic apatite but is present also in the late k feldspar up to 0 15 wt of p2o5 that formed from the residual melts in the postorogenic s type granites the bulk of the phosphorus occurs in alkali feldspar f0 3 wt p2o5 with a minor proportion present in primary early magmatic apatite clusters of small secondary apatite grains with a distinctive composition are distributed in alkali feldspar grains of the post orogenic s type granites this apatite has formed post magmatically from p released from p rich alkali feldspar during decreasing temperature by reaction with a fluid rich in volatiles including f and b and alkali and alkali earth metals a type granites have the lowest bulk phosphorus contents consequently phosphate minerals are relatively rare in this granite type and the alkali feldspar has negligible p2o5 contents except for sr the minor element contents in apatite partly correlate with the bulk composition of their host rocks and partly reflect some thermodynamic properties of melt the mn contents of apatite increase with the peraluminous character of the melt and with decreasing fo2 and so apatite from the s type granites has significantly higher mn contents than apatite from the i type granites apatite from a type granites is enriched in fe and hree reflecting the higher bulk fe and hree content of this granite type apatite from specialized s type granites is enriched in yand hree in general the cl and s content of apatite is higher in the basic members of the i type affinity granitic rocks d 2004 elsevier b v all rights reserved

annual and interannual changes on a reef fringed pocket beach kailua bay hawaii abstract historical aerial photographs and topographic survey sheets are used to establish a 70 year shoreline history 1926 1996 for kailua beach oahu hawaiian islands the shoreline has migrated seaward over this period at an average rate of 0 5 m yr with a maximum net accretion along the beach of 58 7 m and a maximum net erosion of 13 2 m net accretion has taken place even while sea levels have risen on the order of 0 1 m semi annual and monthly beach profile surveys 1995 1999 at seven transects reveal short term variations of shoreline position sand volume and beach shape a relationship between beach width and corresponding sand volume fluctuations established from the beach profile data is applied to the historical shoreline change data to establish a history of sand volume fluctuations results show that kailua has experienced a net accretion of 673 000 m3 of sand over the period 1926 1996 with average annual rates of volume change varying between 6 8 m3 m yr and 0 1 m3 m yr the most recent period 1989 1996 shows a net volume increase of 41 000 m3 given the lack of sand inputs at the ends of the beach exchange with offshore deposits is a likely mechanism for long term accretional trends seasonal fluctuations in kailua beach morphology dominate the variability with a response to seasonal wave state that varies along the length of the beach in magnitude and sign at least four alongshore zones are observed with the first and third zones exhibiting high low sand volumes during the summer winter and the second and fourth zones exhibiting opposite behavior with high low volumes during the winter summer although seasonal sand accumulation varies along the beach the overall beach profile is largely maintained moreover changes in sand volume occur in phase over the subaqueous and subaerial sections of the beach this behavior suggests that longshore rather than cross shore sand transport is important at annual time scales a simple seasonal transport pattern is proposed to account for these observed fluctuations which depends in part on the topography of the offshore reef

human induced changes in the geomorphology of the northeastern coast of the nile delta egypt abstract landsat enhanced thematic mapper imagery etm of 2002 and aerial photography of 1955 combined with published charts and field observations were used to interpret geomorphological changes in the coastal zone between kitchener drain and damietta spit in the northeastern nile delta previously recognized as a vulnerable zone to the effects of any sea level rise resulting from global warming the interpretation resulted in recognition of several changes in nine identified geomorphological land types beach and coastal flat coastal dunes agricultural deltaic land sabkhas fish farms manzala lagoon saltpans marshes and urban centers reclamation of vast areas of the coastal dunes and of manzala lagoon added about 420 km2 to the agricultural deltaic land about 48 km2 of sand dunes marshes sabkhas and salt pans have been converted to productive fish farms the main urban centers have expanded and new urban centers damietta harbor and the new damietta city have been constructed at the expense of vast areas of manzala lagoon coastal dunes and backshore flats as the consequence of human activities the size of manzala lagoon has been reduced to less than 50 short term shoreline changes along the coast of the study area established from beach profile survey spanning the years of 1990 to 2000 reveal longshore patterns of erosion versus accretion the rate of shoreline retreat has increased in the downdrift side of damietta harbor 14 m year whereas areas of accretion exist within the embayment of gamasa and in the shadow of ras el bar detached breakwater system with a maximum shoreline advance of 15 m year a sandy spit 12 km long has developed southeast of damietta promontory these erosion accretion patterns denote the natural processes of wave induced longshore currents and sediment transport in addition the impact of man made coastal protection structures

evidence for distinct stages of magma history recorded by the compositions of accessory apatite and zircon accessory minerals contain a robust and accessible record of magma evolution however they may reflect relatively late stage conditions in the history of the host magmas in the normally zoned criffell granitic pluton scotland whole rock wr compositions reflect open system assimilation and fractional crystallisation at depths of 11 km whereas amphibole barometry and the absence of inherited zircon suggest that the observed mineral assemblages crystallised following emplacement of magmas with little or no crystal cargo at depths of 4 6 km the crystallisation history is documented by large trace element variations amongst apatite crystals from within individual samples decreasing lree and th concentrations in apatite crystals from metaluminous samples reflect broadly synchronous crystallisation of allanite whereas lower lree and th and more negative nd anomalies in apatites from peraluminous samples reflect the effects of monazite crystallisation wr evolution is likely to have occurred within a deep crustal hot zone where h2o rich 6 wt low viscosity magmas segregated and ascended adiabatically in a super liquidus state leading to resorption of most entrained crystals stalling emplacement and crystallisation resulted from intersection with the h2o saturated liquidus at 4 km h2o contents are as important as temperature in the development of super liquidus magmas during ascent blurring distinctions between apparently hot and cold granites the trace element contents of most accessory minerals are controlled by competitive crystallisation of other accessory minerals in small melt batches consistent with the incremental assembly of large granitic plutons

petrogenesis of ore bearing porphyry from the tangjiaping porphyry mo deposit dabie orogen zircon u pb geochronology geochemistry and sr nd hf isotopic constraints abstract extensive early cretaceous post collisional igneous rocks especially the large volume of granitoids developed in the dabie orogen some of these granitic rocks are spatially temporally and genetically associated with economically important molybdenum deposits the tangjiaping large scale 0 1 million ton porphyry mo deposit is located in the northwest of the northern dabie complex unit the mo mineralization is mainly hosted in molybdenite bearing quartz veinlets and stockworks in the tangjiaping granite porphyry which intruded into proterozoic biotite plagioclase gneiss and amphibole plagioclase gneiss two alteration zones from the porphyry centre outwards and downwards can be recognized 1 k silicate alteration silicification zone 2 silicification phyllic alteration zone the tangjiaping ore bearing granite porphyry occurs as an individual stock with an outcrop of 0 4 km 2 la icp ms zircon u pb dating of the tangjiaping granite porphyry yields crystallization age of 115 1 ma which is consistent with the molybdenite re os age of the deposit given by previous studies the tangjiaping granitic rocks are metaluminous and belong to high k calc alkaline and shoshonitic series they are relatively enriched in light rare earth elements and have moderately negative eu anomalies geochemical and mineralogical characteristics indicate that the tangjiaping granite is an a type granite and was generated by partial melting of intermediate felsic rocks at pressures of ca 0 4 0 8 gpa there are high initial 87 sr 86 sr ratios ranging from 0 707367 to 0 709410 and negative e nd t values varying from 15 0 to 14 2 for the tangjiaping granite in situ zircon hf isotopic analyses show that the e hf t values of zircons from the tangjiaping granite porphyry vary from 17 0 to 6 0 the geochemical data and sr nd hf isotopes coupled with the neoproterozoic inherited zircon age 652 21 ma indicate that the tangjiaping granite porphyry was most likely derived from partial melting of the northern dabie gneiss with some relatively enriched mantle materials involved the tangjiaping mo ore forming granite porphyry was formed in an extensional setting the early cretaceous asthenospheric upwelling might have played an important role in the formation of the approximately coeval mo bearing magmas in the dabie orogen

particle motion and the theory of charcoal analysis source area transport deposition and sampling principles from particle motion physics were applied to recurring problems of the interpretation of stratigraphic charcoal data 1 fires within catchments of lakes often produce no record in fossil charcoal curves and 2 periods characterized by no local fire e g 20th century fire suppression often display as much charcoal as times when local fire was frequent quantitative theory on source area transport deposition and sampling of charcoal shows the relationship between particle sizes counted by alternative methods of charcoal analysis pollen slides for particles 5 80 m in diameter petrographic thin sections for particles 50 10 000 m diameter and charcoal diagrams the relationship between diameter and critical and deposition velocities results in fundamental aerodynamic differences between the sizes of particles quantified by the two methods charcoal recorded on pollen slides is of a size that is difficult to lift but once entrained it remains in suspension thin section charcoal is lifted at relatively low wind velocities but it is not suspended at normal surface wind speeds thermal buoyancy during fire lofts charcoal above the forest canopy depending on particle size and wind speed pollen slide charcoal sizes are underrepresented near the fire because they remain in suspension and are preferentially exported from the burn area thin section charcoal is convected to lower heights on average and is deposited nearby following fire thin section charcoal is redistributed locally by wind and thus may enter lakes because of cohesive forces and aerodynamics more pollen slide charcoal remains on the ground and less enters lakes source areas for pollen slide charcoal are subcontinental to global and diagrams of pollen slide charcoal are biased toward nonlocal charcoal they can be used to interpret importance of fire for broad spatial and temporal scales thin section charcoal represents the catchment fire regime simulation models that generate charcoal during fire mix sediments and then sample at specified intervals indicate that 1 in the absence of sediment mixing the pollen slide method should consistently resolve individual fires that occur with an expectation of 30 50 yr 2 unless samples are continuous neither method will produce useful estimates of fire frequency and 3 even a modest amount of sediment mixing will obscure the signal

toward a theory of island pedogeography testing the driving forces for pedological assemblages in archipelagos of different origins abstract the theory of island biogeography has been based on biodiversity studies and used as a powerful predictive tool currently pedogeography does not have a similar theoretical construct although island biodiversity and biological assemblages have been topics of widespread interest in biogeography ecology and conservation biology soil scientists have conducted few studies of pedodiversity and pedological assemblages in archipelagos several studies have demonstrated that pedodiversity and biodiversity patterns have striking similarities in very disparate environments and at different scales thus it is possible to test for a similar construct of island pedogeography we analyze similarities and differences in the pedosphere for three archipelagos with different origins i oceanic intra plate chains islands hawaiian islands ii oceanic intra plate cluster islands canary islands iii non marine land bridge islands with volcanism associated with plate boundary conditions aegean islands and iv as a comparison islands in a nonplate boundary setting the british isles in the canary islands we also compiled selected biological physiographical geological and climatic data for further analysis of pedodiversity climatic diversity geodiversity and biodiversity our pedogeographic analysis of the three archipelagos indicates archipelagos of varying origins contain different soil assemblages with plate tectonics as the main driving force the similarities between pedodiversity and biodiversity are more remarkable than the differences we tested the hypothesis that soil taxa distributions on island chains can be modelled as a power function similar to the species area relationship sar proposed by mcarthur and wilson for archipelagos the sar functional relationship has been widely corroborated in other biodiversity studies the same patterns were obtained for pedodiversity and biodiversity in the british isles and after that in the aegean archipelago in this study we show similar results in the canary islands furthermore in the canary archipelago a strong relationship exists between pedodiversity biodiversity climate diversity habitat heterogeneity and relief for the hawaii archipelago we did not obtain a statistically significant relationship because soil inventories are not published for the smallest islands and islets however hawaii does have a chronosequence from the older to the younger land units overall the dynamics of the underlying plate tectonic hot spots seems to be the major driving force affecting the various diversity types based on these results we suggest a theoretical proposal of island pedogeography consistent and similar to the theory of island biogeography in view that the latter one also predicts the pedodiversity of soil assemblages in archipelagos this study illustrates several possibilities for further research in soil geography

trace element composition of igneous zircon a thermal and compositional record of the accumulation and evolution of a large silicic batholith spirit mountain nevada hafnium u th and ree content of zircons from the spirit mountain batholith in southern nevada correlate with calculated temperatures from the ti in zircon thermometer to support field and petrologic evidence of rejuvenation of crystal mush and melt extraction events during the 2 million year accumulation of the granitoid batholith marked variation in zircon composition from sample to sample from grain to grain within individual samples and from zone to zone within individual grains documents in detail a history of fluctuating conditions with repeated episodes of replenishment reheating crystal mush rejuvenation fractional crystallization and melt segregation the zircons exhibit compositional and thermal variability indicative of variations in host melt composition due to 1 melt rejuvenation mixing and fractionation 2 coeval growth of other ree rich accessory minerals and possibly 3 fluctuation in fo2

the rise of fire fossil charcoal in late devonian marine shales as an indicator of expanding terrestrial ecosystems fire and atmospheric change fossil charcoal provides direct evidence for fire events that in turn have implications for the evolution of both terrestrial ecosystems and the atmosphere most of the ancient charcoal record is known from terrestrial or nearshore environments and indicates the earliest occurrences of fire in the late silurian however despite the rise in available fuel through the devonian as vascular land plants became larger and trees and forests evolved charcoal occurrences are very sparse until the early mississippian where extensive charcoal suggests well established fire systems we present data from the latest devonian and early mississippian of north america from terrestrial and marine rocks indicating that fire became more widespread and significant at this time this increase may be a function of rising o2 levels and the occurrence of fire itself may have contributed to this rise through positive feedback recent atmospheric modeling suggests an o2 low during the middle devonian around 17 5 with o2 rising steadily through the late devonian and early mississippian to 21 22 that allowed for widespread burning for the first time in devonian mississippian marine black shales fossil charcoal inertinite steadily increases up section suggesting the rise of widespread fire systems there is a concomitant increase in the amount of vitrinite preserved woody and other plant tissues that also suggests increased sources of terrestrial organic matter even as end devonian glaciation was experienced fossil charcoal continued to be a source of organic matter being introduced into the devonian oceans scanning electron and reflectance microscopy of charcoal from late devonian terrestrial sites indicate that the fires were moderately hot typically 500 600 c and burnt mainly surface vegetation dominated by herbaceous zygopterid ferns and lycopsids rather than being produced by forest crown fires the occurrence and relative abundance of fossil charcoal in marine black shales are significant in that these shales may provide a more continuous record of fire than is preserved in terrestrial environments our data support the idea that major fires are not seen in the fossil record until there is both sufficient and connected fuel and a high enough atmospheric o2 content for it to burn