provenance of jurassic sediments in the hefei basin east central china and the contribution of high pressure and ultrahigh pressure metamorphic rocks from the dabie shan abstract the provenance of the jurassic sediments in the hefei basin is constrained by compositions of the detrital k white micas and garnets and shrimp dating of the detrital zircons which can help to understand the evolution and to reconstruct the paleogeographic distribution of hp uhp rocks in the jurassic dabie shan 1 for the oldest mesozoic sediments at the bottom of the fanghushan formation j 1 the predominance of the early paleozoic and luliang 1700 1900 ma zircons indicates a major source from the north china block however neoproterozoic zircons as the major component in other jurassic sediments indicate that the source rocks were mainly derived from the exhumed yangtze block in the dabie shan 2 the co occurrence of high si phengites and triassic zircons provides stratigraphic evidence that the first exposure of the uhp rocks at the earth s surface in the dabie shan occurred in the early jurassic during deposition of the fanghushan formation 3 from the east to the west of the hefei basin there is a spatial variation in the compositions for detrital micas and garnets and in the u pb ages of detrital zircons evidently hp uhp rocks were widely distributed at outcrop in the eastern dabie shan in contrast they were less important in the western dabie shan during the jurassic

provenance evolution of collapse graben fill in the himalaya the miocene to quaternary thakkhola mustang graben nepal abstract this study focuses on the detailed provenance evolution of young syn to post orogenic extensional grabens in orogens like the himalaya to trace the tectonic history of such late stage basins using the neogene thakkhola mustang graben as a case study the graben is situated within the tibetan tethys zone and is filled with 870 m of continental deposits of miocene to holocene age based on logged sections within the predominantly alluvial to coarse grained fluvial fill of the graben we investigated paleocurrent data and the petrology of sandstones and conglomerates including heavy minerals studies to interpret provenance and source areas in detail significant changes are recorded by slight differences in heavy mineral and pebble compositions the sandstones can be classified as lithic greywackes lithic arkoses and feldspathic litharenites sandstone mudstone quartzite and some granite clasts are dominant in conglomerates of the central part of the graben tetang formation conglomerates of miocene age comprise mostly clasts of mesozoic rocks with an eastern provenance consistent with measured paleocurrent directions all paleocurrent data and compositional analyses of imbricated conglomerates of the miocene pliocene thakkhola formation in the northeast of the graben suggest that clasts were derived from eastern source areas comprising mainly mesozoic rocks whereas paleozoic clasts of a western to northern source area predominate in the centre of the graben heavy mineral analysis indicates that tourmaline staurolite zircon garnet and apatite constitute a significant proportion of the assemblages of all formations through time whereas epidote andalusite kyanite chloritoid hornblende chrome spinel rutile and amphiboles are less common these assemblages reflect in general stable minerals and low to high grade metamorphic source rocks and are principally controlled by reworking of older passive margin sediments of the tibetan tethys zone as indicated by provenance discrimination diagrams three successive stages in provenance evolution were recognized 1 the miocene tetang formation characterized by higher kyanite values corresponding to the himalayan foreland evolution 2 the thakkhola formation characterized by granite clasts and significantly higher amounts of andalusite indicating source area expansion and erosion of the mustang mugu granites to the northwest 3 the upper pleistocene holocene kaligandaki formation bearing higher amounts of epidote klinozoisite and ophiolite and high pressure low temperature detritus as indicated by chrome spinel and blue amphiboles derived from the north lying indus tsangpo suture zone the change in source areas from the miocene pliocene to the late pleistocene holocene is interpreted as a result of the evolution from an initial stage of high angle normal faulting and collapse basin formation to a low angle extensional detachment basin system

mesozoic cenozoic tectonic relationships between the kuqa subbasin and tian shan northwest china constraints from depositional records abstract stratigraphic profiles in the kuqa subbasin located along the southern flank of the tian shan northwest china display similar mesozoic cenozoic evolutionary sequences of compositional maturity exist in conglomerate clasts sandstone framework grains and detrital heavy minerals the similarity of these time series profiles resulted from orogenesis and intracontinental deformation of the provenance area the ancestral tian shan mineralogical maturities of conglomerates and sandstones increase from triassic to middle jurassic and decrease from upper jurassic lower cretaceous to tertiary this trend parallels a similar decrease in maturity in detrital heavy minerals zircon rutile and tourmaline dominate in middle upper triassic to middle jurassic sandstone whereas unstable hornblende and pyroxene dominate the heavy mineral suites in the tertiary especially in miocene and pliocene strata these compositional trends are coeval with gradual southward migration of alluvial depositional fronts and depositional depocenters from cretaceous to miocene since the pliocene large scale southward migration of alluvial depositional systems occurred while depositional depocenters migrated northward based on the mesozoic cenozoic depositional records the tectonic evolution of the tian shan kuqa subbasin may be divided into five phases 1 in early triassic following compression and uplift since permian gravelly braided river alluvial plain depositional systems developing in the kuqa subbasin characterized by sands of mixed orogenic provenance type derived from the ancestral tian shan 2 from middle triassic to middle jurassic sediment composition of the kuqa subbasin reflects arc orogen and mixed orogenic sand types with extensive planation of the ancestral tian shan and the development of relatively stable coal bearing depositional environments 3 renewed compression uplift of the tian shan occurred in late mesozoic especially in cretaceous with most detrital modes of the kuqa subbasin indicating provenance attributes akin to the south tian shan 4 further intensive compression uplift and probably southward basinward propagation of the south tian shan occurred during miocene and 5 supracrustal gravity gliding and collapse occurred in the tian shan kuqa subbasin probably due to intensive deep compression with rejuvenated uplift and probable southward basinward structural propagation of the south tian shan developing since pliocene observed changes in sediment composition and depositional environment since pliocene time were also controlled by frequent and abrupt climate changes in addition to intensive uplift of the tian shan moreover all depositional records in the kuqa subbasin seem to reflect west to east differences in provenance along the tian shan probably indicating greater exhumation depth in the western tian shan than that in the eastern tian shan since early cretaceous

heavy minerals and garnet geochemistry of stream sediments and bedrocks from the almklovdalen area western gneiss region sw norway implications for provenance analysis abstract detrital heavy minerals commonly document the geological setting in the source area hence they are widely used in sedimentary provenance analysis in heavy mineral studies the 63 125 and 63 250 m grain size fractions are most commonly used heavy mineral data and garnet geochemistry of stream sediments and bedrocks from the catchment area draining the almklovdalen peridotite massif in sw norway reveal that a wider grain size spectrum needs to be considered to avoid misleading interpretations the almklovdalen peridotite massif consists mainly of dunite and harzburgite as testified by the heavy mineral suite at the outlet of the main river the heavy mineral spectrum is very monotonous due to dilution by a strong influx of olivine heavy minerals like apatite and epidote characterising the host gneisses have almost disappeared mgo rich almandine garnets are more frequent in the coarser grain size fractions whereas mno rich almandine garnets are more frequent in the finer grain size fractions garnets with pyrope content exceeding 50 are only found in the 500 1000 m grain size fraction therefore the sample location and the selected grain size fraction are of paramount importance when dealing with heavy minerals and mineral geochemical data otherwise provenance sensitive information may be missed

garnet provenance studies juxtaposition of laurentian marginal terranes and timing of the grampian orogeny in scotland a study of the composition and zoning patterns of detrital garnets from ordovician greywackes from the northern belt of the southern uplands terrane of scotland reveals characteristics of the metamorphic sources very similar to the dalradian supergroup of the scottish grampian terrane the radiometric cooling and uplift ages of the dalradian metamorphic zones and the depositional ages of the southern uplands greywackes support the hypothesis for local provenance detrital metamorphic garnet identical to dalradian garnet has also been identified in the upper ordovican sandstones of the highland border complex these observations do not support proposals that the grampian midland valley and southern uplands terranes were exotic to each other in the late ordovician time these new results together with a review of published age dates clarify the late ordovician palaeogeography for this part of the laurentian margin the distances between the grampian midland valley and southern uplands terranes may have been similar to the present day it is concluded that large rivers flowed out of the uplifting mountainous grampian terrane and across the midland valley into a southern uplands trench during the late ordovician time the main orogeny i e mountain building in the grampian terrane was therefore post cambrian producing the first high mountains and resultant flysch in the caradoc

compositional variation in lower old red sandstone detrital garnets from the midland valley of scotland and the anglo welsh basin compositional variation in lower old red sandstone ors detrital garnets can be used to evaluate potential source areas and to trace the pattern of early devonian sediment dispersal garnets in northwesterly derived fans along the northern flank of the midland valley appear to duplicate spatial variation in the compositions of garnets in the adjacent dalradian block whilst metamorphic clasts resembling dalradian lithologies occur in these fanglomerates the strike extent of dalradian type crust c 1000 km makes simply matching the clasts a rather imprecise way of constraining source basin displacement the garnet data imply that the ordovician separation inferred for crustal blocks juxtaposed along the highland boundary was removed by early devonian times major silurian displacements are thus invoked along the highland boundary with amalgamation largely achieved prior to the acadian transcurrent deformation seen in the slate belts to the south vertical changes in the composition of garnets in the thick lower ors sequence in the northeast midland valley are slight and it is not known to what extent these reflect migration of a differentiated source block or the involvement of recycled additions which become increasingly important towards the base of the ors succession the axially dispersed sandstones which interdigitate with the northwesterly derived fans are dominated by spessartine rich almandines which resemble garnets fed laterally to the basin in the northwest midland valley although the large scale inferred for the axial fluvial system suggests that its drainage basin extended outside scotland almandine pyropes which might have come from exhumed eclogites in western norway are absent such compositions are widespread in mesozoic sandstones in the northern north sea and it is evident that these sediments do not represent the final repository for the lost sediment stripped from caledonian metamorphic terranes in scotland garnet populations from the anglo welsh basin do not resemble those in the coeval axial sandstones of the midland valley suggesting that the two basins were not linked at this time the scale of the midland valley axial sandbodies are inconsistent with internal drainage of central scotland and a route to the early devonian shoreline must be sought it may be that acadian strike slip motions have displaced the scottish basins from the coastal alluvial plains they originally fed

provenance study of early and middle bronze age pottery from kaman kalehoyuk turkey by heavy mineral analysis and geochemical analysis of individual hornblende grains the provenance of early bronze age and early middle bronze age pottery produced between 2100 and 1970 b c and excavated from kaman kalehoyuk turkey was studied using mineralogical methods including heavy mineral analysis and geochemical study of individual hornblende grains the relative abundances of heavy minerals in the fabrics of 20 early bronze age eba and early middle bronze age mba pottery sherds together with 27 local sediments collected within a radius of 25 km of the site were studied the heavy mineral distributions in the kaman region were statistically analyzed for consistencies in their occurrence amphibole was found to be the most abundant heavy mineral in most of the analyzed samples followed by titanite and epidote the amounts of other minerals such as garnet clinopyroxene and zircon are subordinate different proportions of heavy minerals in the fabrics allow categorization of the eba and early mba potteries into 5 groups comparative study of heavy mineral assemblages of local sediments and pottery suggests that half of the eba and most of the mba potteries were produced from sediment near the excavation site whereas the other half of the eba potteries were produced from sediment occurring at 25 km east or more east of the site the geochemistry of individual amphibole grains was studied by electron microprobe analysis most of the studied amphibole grains are calcic and aluminous corresponding to hornblende they can be further characterized into four types based on their chemical composition the combination of heavy mineral identity and hornblende geochemistry provides diagnostic evidence for the origins of kaman kalehoyuk pottery these and analogous heavy mineral techniques are effective archaeometric tools for determining pottery provenance

an application of heavy mineral analysis to lithostratigraphy and reservoir modelling in the oseberg field northern north sea abstract three distinctive detrital garnet associations have been recognized in brent group sandstones of the oseberg area northern north sea by means of electron microprobe analysis these have lithostratigraphical significance with one association occurring in the etive and oseberg formations one in the ness formation and one in the tarbert formation the stratigraphic variation in garnet population reflects changes in provenance and in the pattern of distribution of clastic detritus although a detailed reconstruction of source areas is not possible on the basis of the available information differentiation of ness and etive oseberg formations by means of detrital garnet geochemistry has enabled the recognition of fluvial chanbel sandstones belonging to the ness formation which have cut down into the etive formation shoreline complex this provides direct evidence of communication between ness and etive oseberg adding an extra degree of sophistication to the geological input for reservoir simulation a strong permeability anisotropy can be modelled around the fluvial channels and a net sand volume can be modelled in agreement with channel orientation

subsurface dissolution of heavy minerals frio formation sandstones of the ancestral rio grande province south texas abstract oligocene sandstones frio formation of south texas deposited by the ancestral rio grande contain a heavy mineral assemblage that is markedly altered even in the shallowest sample examined approximately 1 km depth the weight fraction of detrital heavy minerals in the modern rio grande is approximately 1 whereas subsurface frio sandstones contain as little as 0 1 or less heavy minerals modern rio grande sand contains a diverse and unstable heavy mineral assemblage dominated by pyroxenes amphiboles and an assortment of iron titanium oxides minor components include apatite garnet sphene epidote and zircon heavy minerals in subsurface oligocene sandstones include abundant apatite zircon and titanium oxide among detrital components minor iron rich garnet also survives in the subsurface to depths of about 3 km other very stable but also very minor heavy minerals include tourmaline chromite spinel and monazite locally the heavy mineral fraction in the frio is dominated by authigenic components such as siderite pyrite or barite authigenic sphalerite is also observed among the heavy minerals feldspars and rock fragments suggest that sediment deposited by the ancestral rio grande was more strongly dominated by volcanic detritus than is the modern river it is reasonable to infer that the initial heavy mineral assemblage of the frio formation was likewise more unstable than that which appears today in the rio grande thus heavy mineral loss determined by comparing subsurface frio sandstones with the sand in the modern rio grande is conservative comparison of sr and nd concentrations in modern rio grande sands and subsurface frio sandstones suggests that heavy mineral destruction in the subsurface does not cause major perturbations of whole rock isotopic systems involving these elements

modal composition and detrital clinopyroxene geochemistry of lithic sandstones from the new england fold belt east australia a paleozoic forearc terrane the new england fold belt of southeast australia is divided by the peel fault system into two time equivalent zones showing contrasting depositional structural and metamorphic histories these are inferred to represent a western magmatic arc frontal arc succession and an eastern subduction complex assemblage the composition of the early to middle paleozoic clastic rocks from both east and west of the peel fault system indicates derivation from an undissected volcanic arc detrital quartz is absent or present only in minor amounts and always as monocrystalline grains lithic fragments are almost exclusively volcanic and normally dominant over feldspar which is invariably plagioclase now largely albitized to the west of the fault the distribution of lathwork microlitic felsitic and vitric rock fragments as well as variation in the amount of detrital quartz indicates changes in provenance through time and two cycles of basaltic to silicic volcanic activity have been identified the composition of detrital calcic clinopyroxene grains particularly their low ti and al contents and their ti mn na ratios indicates that they crystallized mainly from subalkaline probably calc alkaline volcanic arc magmas the dominantly volcanogenic provenance of sandstone from east of the fault and the low ti content of most detrital clinopyroxene grains indicate that the volcanic chain that lay to the west of the peel fault was the most likely source for the major portion of the clastic debris in the eastern rocks however the presence of ti rich detrital clinopyroxenes identical in composition to those in the metabasalts of the subduction complex indicates that uplifted segments of the complex provided an additional sediment source

integrated microstratigraphic investigations of coastal archaeological soils and sediments in norway the gokstad ship burial mound and its environs including the viking harbour settlement of heimdaljordet vestfold investigations of past coastal landscape development have included soil micromorphology chemistry and microfossil recording of soils and sediments associated with marine inundation and terrestrial soil formation in marine sediments this paper reports on similarly studied site formation processes at norwegian coastal sites in vestfold norway the viking period gokstad ship burial mound and nearby contemporary harbour site of heimdaljordet at gokstad strategically focused coring revealed mound composition and an example of its buried soil and geology the latter investigation suggested that post glacial uplift led to a slowstand period of intertidal reworking of till before 700 bc emergence and development of terrestrial soils at heimdaljordet typically laminated intertidal silty clay loam sediments were sealed by beach sands into which for example a boat grave was dug post depositional processes affecting the gokstad mound were compared to those in other mounds including those recorded in experimental earthworks waterlogged conditions in the gokstad mound led to iron phosphate migration and preferential deposition of vivianite in turf layers where relict litter l layers remained visible and where wood chips from constructional activities are also very well preserved as is the long ship itself these soil insights and other paleoenvironmental studies of the buried soil and numerous turf sequences showed that the contemporary ad 900 viking landscape was totally terrestrial it had become wet sedge grassland managed for grazing the partial weathering of turves and anomalous presence within them of fresh roots apparently indicates the possibility that turves were stacked and stored ahead of mound building the 10th c robber trench had developed muddy features and rooting traces show that it was not backfilled but was slowly infilled by humic soil silting from turf mound layers this event did not affect the overall anaerobic burial conditions in the mound which can be starkly compared to those at the heimdaljordet boat grave here because of acidic subaerial weathering the wooden boat only survives as an acidic pellety humus formed of wood residues that are often ferruginised iron appears to be concentrated at iron nail locations unlike the gokstad mound no bone survives but one sample found a typical body stain of secondary iron and phosphate close by the iron encrusted sword in the grave potentially the pelvic region of the inhumation here mineralised faecal gut remains have an assumed hydroxyapatite composition and embed phytoliths and pollen spores as found in human coprolites and cess deposits studied elsewhere

the origin of faceted garnets in sandstones dissolution or overgrowth faceted garnets from a wide range of geological ages environments and locations have been studied in polished grain mounts by a combination of backscattered electron microscopy and elemental mapping using energy dispersive x ray analysis in all cases the areas apparently showing positive relief on the faceted garnet surfaces are compositionally identical to the adjacent grain cores despite a wide variation in detrital garnet compositions in one case zoning within the grain core can be traced into the faceted areas on the grain surface thus faceted areas must be considered to form part of the original detrital grains together with previously published studies on experimental garnet etching thermodynamic conditions for garnet growth textural relationships between faceted garnets and authigenic and detrital phases and distribution of faceted garnets in the subsurface this paper provides conclusive proof that faceted garnet surfaces form as a result of dissolution not overgrowth

heavy minerals as a guide to turbidite provenance in the lower palaeozoic southern welsh basin a pilot study a pilot study has demonstrated that heavy mineral analysis is a useful guide to the provenance of silurian turbidites in the southern welsh basin the results confirm the sedimentological evidence for two distinct source areas of coarse clastic detritus one lying to the south and the other to the east they also provide mineralogical criteria by which the two source areas may be distinguished the southern area provided material with relatively low mineral diversity and is characteristic in having low rutile zircon ratios whereas the eastern source provided more diverse assemblages generally with high rutile zircon ratios the southern source shows variations in terms of apatite tourmaline ratio with the older aberystwyth grits group tending to contain relatively low apatite compared with the younger cwmystwyth grits group rhuddnant and pysgotwr grits formations there is evidence for polycyclic material and volcanic detritus in both southerly and easterly derived samples however easterly sourced sandstones apparently tapped a more lithologically diverse terrain

european ancient settlements a guide to their composition and morphology based on soil micromorphology and associated geoarchaeological techniques introducing the contrasting sites of chalcolithic bordusani popină borcea river romania and viking age heimdaljordet vestfold norway specific soil micromorphological broader geoarchaeological and environmental archaeology signatures of settlement activities and land use have been identified from numerous case studies across europe from romania to western norway in order to demonstrate how such investigations contribute to our understanding of settlement morphology and its wider landscape an improved way of organising site specific information or guide was created macphail and goldberg in press activities and land use are divided into within settlement peripheral to settlement and the settlement s wider landscape major themes identified are constructions and materials trackways and paths and other communication transport associated features animal management water management waste disposal 1 middening 2 human waste specialist domestic and industrial activities and funerary practices in the case of trackway deposits their characterisation aids the identification of intensely occupied areas compared to rural communications although changing land use within urban areas has also produced rural signatures e g as associated with animal management for example in late roman cities specialist activities such as fish and crop processing or working with lead and other metals in field and within wall manuring stabling and domestic occupation floor use evidence and identification of different funerary practice cremations boat graves and other inhumations and excarnation features and peripheral constructions such as boat houses are also noted new information from the chalcolithic tell site of bordusani popin romania and seasonally occupied viking settlement of heimdaljordet norway is introduced

the provenance of garnet constraints provided by studies of coastal sediments from southern india abstract the provenance of sediment with heavy mineral suites containing garnets with low grossular and high pyrope contents is enigmatic such garnet assemblages characterise sediments in many basins worldwide they are especially common in the sedimentary basins around northern britain but their source cannot be identified in adjacent basement rocks this paper documents garnet populations in beach dune and river sands from southern india which almost exclusively comprise low grossular high pyrope garnets these are derived from the high grade granulite facies metasedimentary and charnockitic rocks that form the basement in this area by analogy similar lithologies are inferred to source sediments with low grossular high pyrope garnet assemblages seen elsewhere in the case of the sandstones of northern britain the most likely location of such material is considered to be greenland

the use of heavy mineral correlation for determining the source of impact ejecta a manicouagan distal ejecta case study due to the nature of distal impact ejecta layers on earth preserved deposits are rare and are commonly altered by diagenetic weathering processes to establish the source of ejecta trace element signatures of impact glasses have typically been used to establish the source crater of a deposit however in many cases impact glasses in ejecta deposits are devitrified and altered to clays resulting in loss of original melt and original trace element composition this is the case for the late triassic ejecta deposit of sw britain where impact melt spherules have been completely altered to clay this late triassic ejecta deposit was originally believed to be derived from two possible sources the rochechouart or manicouagan impact structures to accurately establish the source of this ejecta deposit an alternative correlation technique was developed using garnet major oxide data and radiometric whole grain fusion ar ar dating of shocked biotite u pb dating of zircon was also used but proved inconclusive radiogenic dating of shocked biotites observed exclusively in the ejecta deposit yielded ages consistent with the grenvillian target rocks at manicouagan and excluded rochechouart as a potential source garnet major oxide compositions of garnets in the ejecta deposit were directly compared to garnets from the manicouagan target rocks and impactite rocks a strong garnet composition signature correlation between the samples from manicouagan and the ejecta deposit provides convincing evidence that manicouagan is the source of the sw britain ejecta deposit furthermore we suggest that heavy mineral correlation techniques should be considered in future studies as a correlation tool for establishing the source of ejecta

using detrital garnet compositions to determine provenance a new compositional database and procedure detrital garnet compositions can be used to help determine the provenance of sedimentary rocks in this study a garnet compositional database consisting of more than 2500 wet chemical and electron microprobe analyses was compiled from the literature for the garnets in the database the six principal garnet end member compositions pyrope almandine spessartine uvarovite grossular and andradite were calculated a multi stage methodology was devised to match garnet compositions to source rocks and a series of garnet provenance fields on ternary plots were identified the method was tested using compositional data from detrital garnet studies in several areas where provenance has already been identified with good results the methodology was then used to assess the provenance of detrital garnets from neogene sandstones of northern sabah borneo for which provenance is unknown and in a region where there are few garnet analyses for comparison comparison of garnet compositions from possible sources on palawan philippines and in borneo combined with the ternary plots excludes some known garnet bearing rocks as potential sources and suggests derivation of metamorphic and igneous garnets from palawan during the early miocene

provenance analysis of lower cretaceous sindong group sandstones in the gyeongsang basin korea using integrated petrography quartz sem cathodoluminescence and zircon zr hf analysis the sindong group aptian albian in southeastern korea is a 2 3 km thick fluvio lacustrine sedimentary package deposited in an elongated basin the nakdong trough which was formed by extension in an active continental margin setting the provenance of the sindong group was studied to understand spatial and temporal variation in composition in three different parts of the basin by using integrated data on petrography quartz sem cathodoluminescence cl analysis and zircon zr hf analysis although sindong group sandstones display wide variation in the composition of framework grains they generally have increasing amounts of feldspar and decreasing amounts of quartz up sequence significant amounts of volcanic rock fragments and volcanic quartz are observed in the late stage sediments metamorphic quartz is predominant in all sindong group sandstones indicative of the exposure of metamorphic rocks in the source terrane mostly from precambrian basement and triassic granites the occurrence of significant amounts of plutonic quartz from early stage sediments suggests that jurassic granites were widely exposed in the source terranes in addition the episodic increase in volume of plutonic quartz content in the sequence especially in the northern part of the basin suggests that episodic tectonic activity occurred in the catchment the increasing feldspar content up sequence could support the occurrence of tectonic activity in the catchments the zr hf analysis of detrital zircons revealed that the majority of zircons are of continental crust origin formed in orogenic settings but zircons in the lowest strata in the northern part of the basin were derived largely from anorogenic magmatic rocks of mantle origin our results demonstrate that source terranes for the sindong group have heterogeneous spatial and temporal distribution and were composed mainly of precambrian basement and triassic to jurassic granitic rocks with minor meta sedimentary rocks and syndepositional volcanic rocks the detritus derived from syndepositional volcanic rocks became significant in the late stage of basin filling representing the transition from extensional tectonism to continental arc magmatism the differences in characteristics of quartz sem cl and zircon zr hf ratios in different parts of the basin are best explained by deposition on different alluvial fans and river systems

an integrated study of dark earth from the alluvial valley of the senne river brussels belgium abstract the present article discusses the integration of urban geoarchaeological and archaeobotanical data of a series of dark earth deposits situated in the alluvial valley of the senne river in brussels belgium due to their homogeneous character their interpretation is a huge challenge for archaeologists through a case by case approach a detailed picture of the sequence of different activities and semi natural events leading to the build up of dark earth at each individual site has been obtained among the activities agricultural practices and waste management which are rarely archaeologically recorded in urban contexts have been identified despite being situated in a valley context none of the sites presented an excellent preservation of the organic plant remains however through the integration of geoarchaeological and botanical data the taphonomical history of the botanical remains could better be understood allowing us to document the evolution of the environment surrounding the sites additionally it has been demonstrated that the botanical study of dark earth units can also provide valuable information on vegetal consumption in particular fruits on a broader scale this integrated geoarchaeologial and archaeobotanical study sheds some light on the process of urbanisation of the senne alluvial valley between the 11th 12th and the 16th century ad

areal melt and discharge modelling of storglaciaren sweden a grid based glacier melt and discharge model was applied to storglaciaren a small valley glacier 3 km 2 in northern sweden for the melt seasons of 1993 and 1994 the energy available for melt was estimated from a surface energy balance model using meteorological data collected by automatic weather stations on the glacier net radiation and the turbulent heat fluxes were calculated hourly for every grid point of a 30 m resolution digital terrain model using the measurements of temperature humidity wind speed and radiative fluxes on the glacier two different bulk approaches were used to calculate the turbulent fluxes and compared with respect to their impact on discharge simulations discharge of storglaciaren was simulated from calculated meltwater production and precipitation by three parallel linear reservoirs corresponding to the different storage properties of firn snow and ice the performance of the model was validated by comparing simulated discharge to measured discharge at the glacier snout depending on which parameterization of the turbulent fluxes was used the timing and magnitude of simulated discharge was in good agreement with observed discharge or simulated discharge was considerably underestimated in one year

middle miocene denudation of the higher himalayan crystallines revealed by chemical composition of detrital garnets from the siwalik foreland basin sediments western and central nepal abstract the middle miocene to early pleistocene siwalik group is composed of sediments deposited in the himalayan foreland basin in this study the heavy mineral assemblage and chemical composition of detrital garnets from the sandstones in the lower siwalik sub group which are exposed along the karnali river in western nepal and the tinau khola in central nepal are studied and the provenance shift during the middle miocene is discussed the heavy mineral assemblage in the lower section of the lower siwalik sub group is characterized as predominantly zircon tourmaline rutile chemical analysis of the detrital garnets showed a monomodal almandine rich composition with low pyrope prp

evaluation of sediment provenance using magnetic mineral inclusions in clastic silicates comparison with heavy mineral analysis magnetic fe oxide inclusions within framework clastic grains in sediments provide an indication of the provenance of the enclosing host silicate particles magnetic mineral inclusion characterisation is performed using a variety of magnetic properties that are related to magnetic mineral abundance magnetic grain size domain state oxidation state and magnetic grain interaction the magnetic methodology extends that based on a conventional set of environmental magnetic measurements using a variety of recent sediments transported from known rock sources within the uk and eire it is demonstrated using discriminant function analysis that the magnetic properties of the fe oxide inclusions provide a clear distinction of primary provenance this is both at the large scale in terms of various gneiss schist and granite sources and also at a smaller scale when considering subdivisions of these sources using case studies from the marine upper jurassic piper formation and non marine triassic sediments otter bank sandstone and foula sandstone formations it is shown that provenance differences clearly expressed by the results of heavy mineral analysis are also sensitively displayed by the magnetic mineral inclusion data the provenance classification is based around use of hierarchical cluster analysis and multidimensional scaling simple statistical tools are developed to determine a least noisy subset of magnetic parameters which are most suitable for stratigraphic provenance discrimination the triassic case study has indicated the magnetic mineral inclusion technique is most sensitive when using the sediment fractions larger than 150 m

garnet compositions in scottish and norwegian basement terrains a framework for interpretation of north sea sandstone provenance detrital garnets have proved to be useful discriminators of north sea sandstone provenance because they show a wide range of potential compositions and are relatively stable during burial diagenesis it has been less easy to use garnet data to provide a direct link between sediment and source because of the lack of a comprehensive database of garnet compositions in basement terrains forming the north sea hinterland this paper presents garnet compositional data from river sediments sourced from northern scotland and norway and demonstrates the presence of marked variations in garnet compositions from different regions related to fundamental differences in basement lithology the value of the river sediment database is demonstrated by comparing it with garnet compositions in paleocene sandstones from the north sea and more basins enabling the establishment of direct links between source and sediment paleocene sandstones in the gannet field area on the southwestern margin of the central north sea were derived from the dalradian of the grampian highlands those in the northern north sea were derived from the moine dalradian rocks of shetland and those along the more basin margin were derived from western norway by contrast paleocene sandstones in the nelson field central north sea and in the beryl embayment northern north sea have a garnet component that cannot be readily traced back to any basement terrain in either scotland or norway this component which was ultimately derived from granulite facies metasediments or charnockites is interpreted as being recycled from triassic sandstones which were themselves derived from an exotic source probably to the west of the british isles q 2004 elsevier ltd all rights reserved

comments on the paper entitled the heavy minerals of the kurnub sandstone early cretaceous of jordan by s nasir and w sadeddin

origin of deep sea clastics of the magura basin eocene makovica sandstones in the outer western carpathians with constraints of framework petrography heavy mineral analysis and zircon geochronology abstract petrographic examination heavy mineral analysis and detrital zircon u pb dating were performed on the eocene siliciclastic rocks in the raca unit of the outer western carpathians in order to reveal their origin and establish the development of the magura basin during the eocene the medium to fine grained sublitharenites and quartzarenites were mainly derived from extra basinal sources and the deposits predominantly contain minerals from metamorphic rocks the terrigenous material was derived from low to medium grade metapelites and granitoids the sedimentation was also controlled by a sediment supply from the mafic source the basic and metabasic rocks contain pyrope rich garnets and cr spinels palaeo currents document that the sedimentary material was supplied from the south east the first detrital zircon u pb ages confirm zircon producing events occurring in the proterozoic from approximately 2200 to 590 ma but predominantly in the paleozoic between 550 and 60 ma the palaeocurrent indicators petrographic data heavy mineral spectra and zircon geochronology strongly suggest that the tisza mega unit variscan crystalline basement erosion with accompanying sedimentary cover supplied the magura basin from the south the mecsek zone is also suggested to support the villani bihor and part of the bekes codru zones in supplying the magura basin during the eocene to oligocene the eocene transport of significant detrital material to the magura basin is also related to erosion of the marmarosh massif proterozoic ordovician low to medium grade crystalline basement therefore it is most likely that magura basin sedimentation was dominated by supply from the sub ophiolitic fore marmarosh suture zone of the eastern carpathians

marine inundation effects on archaeological features materials sediments and soils abstract the taphonomic effects of freshwater and marine inundation on archaeological sites and their soils and sediments at approximately ten buried soil locations is briefly reviewed from prehistoric coastal sites in southern england and wales including lower palaeolithic boxgrove west sussex these data are discussed in the context of effects of saline groundwater and experimental marine flooding 2006 2008 at wallasea island river crouch essex a preliminary attempt to model transformations caused by rising groundwater freshwater inundation rising saline groundwater and marine inundation is made

timing and depositional environments of a middle pleistocene glaciation of northeast england new evidence from warren house gill county durham at various times during the quaternary north eastern england was a zone of confluence between dynamic ice lobes sourced from the pennines northern scotland the cheviots and scandinavia the region thus has some of the most complex exposures of middle to late pleistocene sediments in britain with both interglacial and glacial sediments deposited in terrestrial and marine settings we investigated sedimentary sequences exposed on the coastline of county durham at warren house gill and present a new model of british and fennoscandian ice sheet interaction in the north sea basin during the middle pleistocene the stratigraphy at warren house gill consists of a lower diamicton and upper estuarine sediments both part of the warren house formation they are separated from the overlying weichselian blackhall and horden tills by a substantial unconformity the lower diamicton of the warren house formation is re interpreted here as an mis 8 to 12 glaciomarine deposit containing ice rafted lithics from north eastern scotland and the northeast north sea and is renamed the ash gill member it is dated by lithological comparison to the easington raised beach middle pleistocene amino acid racemisation values and indirectly by optically stimulated luminescence the overlying shallow subaqueous sediments were deposited in an estuarine environment by suspension settling and bottom current activity they are named the whitesides member and form the uppermost member of the warren house formation during glaciation ice rafted material was deposited in a marine embayment there is no evidence of a grounded onshore scandinavian ice sheet in county durham during mis 6 which has long been held as the accepted stratigraphy this has major implications for the currently accepted british quaternary stratigraphy combined with recent work on the middle pleistocene north sea drift from norfolk which is now suggested to have been deposited by a scottish ice sheet the presence of a scandinavian ice sheet in eastern england at any time during the quaternary is becoming increasingly doubtful

a new palaeogeographic reconstruction for the middle jurassic of the northern north sea an estuarine sequence equivalent in age to the brent group deltaic deposits further north is recognized in the central viking graben it indicates a persistent marine connection southwards from the boreal ocean during deltaic accumulation and suggests that the brent delta did not prograde from the south along the graben as previously suggested evidence from the uk north viking graben indicates the brent delta was probably derived transversely rather than axially as were the other jurassic clastic systems infilling the graben

provenance of the carboniferous hochwipfel formation karawanken mountains austria slovenia geochemistry versus petrography this study focuses on the carboniferous sediments of the karawanken mountains austria slovenia to identify possible source areas and their geotectonic setting provenance analyses have been applied using petrographical and geochemical approaches what also lead to an evaluation of the used methods within the hochwipfel formation five stratigraphic related petrofacies groups can be defined using the sandstone component inventory homogenous provenance results based on major element and trace element data suggest an active continental margin continental island arc with probably an intraplate signature provenance analyses of light minerals point to source areas with basement rocks mainly metamorphic arc material and sedimentary rocks in combination the rapid and highly variable change of provenance signatures within the stratigraphic succession of the petrofacies types excludes a single provenance in the western part of the karawanken mountains additionally changes in composition of the individual petrofacies groups correlate with the stratigraphy in the eastern part varying contents of garnet chromite hornblende and epidote within the sedimentary succession of the hochwipfel sandstones can partly be attributed to geodynamical changes in the hinterland the chemical compositions of garnets tourmalines and chromites confirm the results of both geochemistry and sediment petrography in a quantitative approach based on petrography we can see an equal mixture of all source areas whereas quantification with a geochemical approach results in c 11 of material that can be attributed to a passive continental margin source 28 to 37 to an active continental margin c 44 to a magmatic arc setting and 16 to 19 to an oceanic within plate source area the resulting model for the geodynamical setting of the hochwipfel basin during the late palaeozoic can be best explained by a forearc basin in the eastern part and various pull apart basins in the western part connected through bypasses at the continental margin of gondwana and the palaeotethys as an additional outcome this study clarifies that geochemically derived provenance results based on bulk rock and mineral composition recognize best complex geodynamical settings and a mixture of sources since they incorporate best the provenance significant lithic components on the other hand it points out that an application of additional petrological approaches does not necessarily lead to further information and an elimination of errors but could be essential to define general information of the investigated stratigraphy like the correlation of deposits with stratigraphy petrofacies groups

a new approach to provenance studies electron microprobe analysis of detrital garnets from middle jurassic sandstones of the northern north sea reading provenance from heavy mineral suites is hampered by the depletion of diagnostic but unstable heavy minerals through intrastratal solution a common phenomenon in deep sedimentary basins such as the north sea this paper demonstrates the potential of electron microprobe analysis in overcoming this problem by concentrating on the compositional variations shown by detrital garnets which are relatively resistant to intrastratal solution studies of the garnets from the brent group middle jurassic of the murchison and tern oilfields in the northern north sea reveal that three distinct areas supplied detritus association 1 which characterizes the broom formation in both areas and recurs higher in the sequence in the tern field is ascribed to an orkney shetland source the location of the areas supplying the garnets of association 2 best represented in murchison and association 3 common to both fields is less clear their ultimate sources clearly include high grade metamorphics and therefore probably lie on the norwegian landmass the orkney shetland platform or conceivably the scottish landmass but the possibility of recycling makes it difficult to judge their immediate provenances nevertheless the presence of three garnet associations indicates that the most widely accepted model of brent sedimentation with sands derived from a domal uplift in the outer moray firth and channelled northward along the viking graben is untenable

detrital garnet and chromian spinel chemistry of permian clastics in the renge area central japan implications for the paleogeography of the east asian continental margin abstract the japanese islands comprise a complex assembly of allochthonous continental shelf deposits and subduction related accretionary complexes the paleogeography of permian clastic strata was restored based on chemical analysis of detrital garnets and chromian spinels which are useful for provenance discrimination detrital garnet assemblages from the permian clastic rocks in japan are characterized by a grandite rich assemblage and a grandite poor assemblage most trench fill deposits in permian accretionary complexes contain the grandite poor assemblage which is composed of spessartine rich almandine grossular rich almandine and rarely pyrope rich almandine and is commonly associated with chromian spinels and volcanic rock fragments it is suggested that the sediments were derived from a volcanic arc and associated non calcareous contact metamorphic rocks along the north china block where pelitic granulites including pyrope rich almandine garnets are extensively exposed in the northern margin ophiolite and high p t schist also crop out along the continental margin most permian shelf deposits and the trench fill deposits of the central part of the accretionary complexes in japan contain the grandite rich assemblage analyses suggest provenance from a calc alkaline volcanic arc and association with calcareous contact metamorphic rocks including skarn deposits sediments lack ophiolite detritus a part of the grandite poor trench fill deposits of the accretionary complexes is overlain by grandite rich clastic rocks this indicates that the grandite rich detritus increased and the supply extended through the fore arc basin to the trench the trench fill deposits in the northernmost part of the permian accretionary complex in the renge area yield a grandite poor assemblage particularly uvarovite rich andradite garnets and chromian spinels derived from a back arc basin basalt which is very similar to the clastic composition of the permian back arc basin strata of japan hence we conclude that a back arc basin existed in the northernmost region of the permian subduction zone along the north china block

assessing detrital garnet chemical composition as a quantitative provenance tool a multivariate statistical approach abstract chemical analysis of detrital garnet is a widely utilized quantitative tool for determining the provenance of sediments the goal of this study is to investigate the ability of the compositions of detrital garnet to provide a direct linkage to the specific source rocks from which the garnet was derived to achieve this goal we analyzed detrital garnet isolated from alluvial samples collected from the french broad river and several of its tributaries a watershed that drains portions of the multiply deformed southern appalachian orogen usa to test whether potential linkages between detrital and potential source rock garnet could be achieved garnet crystals were chemically characterized from a wide variety of lithologies that crop out in the french broad watershed and thus are the most likely local sources of detrital garnet mahalanobis distances measured on canonical discriminant functions successfully differentiated garnet compositions among the 18 analyzed source rocks these metrics were then applied to 2 300 detrital garnet compositions to link each grain to its potential source rock approximately 94 of the detrital garnet crystals were linked to their potential source regions thus only 6 of the detrital crystals were treated as unclassified we interpret the unclassified high ca garnets to have been derived from minor sub map scale lenses and boudins of calc silicate or skarns from exposed ocoee or ashe metaclastic units within the french broad river watershed the unclassified high mn detrital garnet grains are interpreted to have been derived from the various felsic granitiods and pegmatites that intrude the region of study

unusual phosphate concretions related to groundwater flow in a continental environment abstract occurrence of phosphate cemented sandstone concretions in alluvial sand containing archaeological layers implies that they have formed during the last 2000 years morphology and petrography of the concretions indicates a relationship with groundwater cementation the phosphate cement of the concretions consists of concentric isopachous aureoles about 10 m thick that wrap the detrital grains aureoles are formed of collophane the cryptocrystalline or amorphous variety of hydroxyapatite geochemical modeling indicates that the apatite cement likely results from the leaching of a preexisting phosphate deposit bones in an acidic soil environment and the precipitation of dissolved phosphate under ph control at the mixing zone of down moving soil water with the calcite saturated groundwater

soil formation as affected by pit and mound microrelief in massachusetts usa abstract the influence of pit and mound microrelief on soil formation was investigated by detailed observations of a cross section through a pit and mound in a hemlock tsuga canadensis forest in western massachusetts in the northeastern united states soil forming processes during the last 140 years have led to taxonomically different soils due to this microrelief part of the annual precipitation apparently does not infiltrate into the mound but moves laterally through organic surface layers into the pits this resulted in more intensified translocation of fe al and organic matter in the pit profile the ensuing soil met the spodic horizon criteria as defined in soil taxonomy and was classified as a lithic haplorthod neighboring undisturbed soils had pronounced e bhs and bs horizons the latter qualifying as spodic horizons on the basis of chemical criteria these soils however did not meet the minimum depth requirement of 12 5 cm for spodic horizons and therefore were classified as typic dystrochrepts the soil developed in the mound showed less horizon development and was classified as a typic dystrochrept taxonomic changes resulting from the pit and mound microrelief affected less than 6 of the area and appeared not to have a significant impact on the purity of map delineations

evolution of paleocene sediment dispersal systems in the foinaven sub basin west of shetland heavy mineral assemblages in deepwater paleocene sandstones of the foinaven sub basin west of shetland reflect the influence of three main provenance and dispersal systems the schiehallion system has relatively uniform characteristics and persisted through much of the early mid paleocene its sphere of influence was centred on the schiehallion field but it progressively encroached into the foinaven area with time its main source was the triassic foula formation with minor supply from lewisian and moine basement rocks the foinaven system shows marked changes in character related to evolution of the source area the earliest sands were derived from a heavily weathered late cretaceous regolith and represent the onset of uplift and exhumation of the shetland platform progressive unroofing led to the incorporation of increasing amounts of lewisianand moine sourced detritus following deposition of the main reservoir sandstones in foinaven and schiehallion there was a progressive change in provenance with a gradual increase in the amount of sediment shed directly from metamorphic basement pulsing of the proto icelandic plume has been proposed as the mechanism for repeated influx of sand to the basins around scotland however on the basis of available geochronological data there does not appear to be a direct link between events in the british tertiary igneous province btip and changes in provenance in the foinaven sub basin the initial influx of sediment from a weathered land surface may have been coeval with the onset of magmatism in the btip but the cessation of supply through the foinaven system at c 59 ma does not appear to be related to magmatic events in the btip the waning of magmatism in the btip around 58 ma is broadly coincident with a gradual increase of first cycle basement detritus please contact us if you would like a copy of this paper

provenance of heavy mineral deposits on the northwestern shelf of the south china sea evidence from single mineral chemistry abstract a study of heavy mineral geochemistry has been carried out in order to examine the potential sources of heavy mineral deposits within surficial sediment on the northwestern shelf of the south china sea tourmaline amphibole and garnet from six samples near the coast and eleven samples on the shelf were analyzed by an electron microprobe chemical varieties of tourmaline and amphibole indicate that the pearl river is the main supplier of sandy sediments on the eastern shelf within a 100 km radius west of the paleo deltas sandy sediments on the western shelf are mainly sourced from the jian river and the wanquan river heavy mineral placers on the middle and outer shelves are mainly derived from reworking of the paleo pearl river deltas heavy mineral placers in the west are mainly sourced from the small rivers and are distributed in the sandy deposits near the coasts this study demonstrates that the occurrence of heavy mineral placers on wide continental shelf is mainly determined by the sediment supply and marine processes during transgressions

faceted garnets from sandstones of the munising formation cambrian northern michigan petrographic evidence for their origin by intrastratal dissolution imbricate wedge marks facets on garnets in sandstones of the cambrian munising formation of northern michigan are associated with mouldic secondary porosity developed at the expense of garnet mouldic pores surrounding faceted garnets indicate that garnets in these sandstones have been affected by intrastratal dissolution retreat of the mineral surface from its original boundaries rather than by grain enlargement which would be expected if garnet overgrowths had formed the association of garnet facets with textural evidence of garnet dissolution proves that garnet facets form by intrastratal dissolution these results confirm similar findings in other recent studies and extend the geographic and stratigraphic range of proven occurrences of facet formation by intrastratal dissolution

changes in garnet chemistry show a progressive denudation of the source areas for permian jurassic sandstones southern kitakami terrane japan abstract garnet is a widespread detrital mineral in permian jurassic sandstones of the southern kitakami terrane electron probe microanalyses of these garnets show a gradual change of chemistry with the age of the sandstones the dominant garnet suites in permian triassic sandstones are grandite with some spessartine almandine in upper triassic sandstones however in lower jurassic sandstones pyrope almandine and spessartine almandine garnets are common whereas grandite garnets are absent garnet suites in middle to upper jurassic sandstones are dominated by pyrope almandine garnet the grandite dominant suites are associated with hornblende epidote and titanite whereas the pyrope almandine dominant suites are associated with biotite these grandite garnets are rich in andradite and have very low spessartine almandine and pyrope contents some of the grandite garnets are anisotropic with oscillatory zoning and sector twinning typical of calcic skarn deposits spessartine almandine garnets are common in low grade metamorphic rocks the diverse suites of pyrope almandine garnets up to 42 mol pyrope from the jurassic sandstones are typical of epidote amphibolite to granulite facies metamorphic rocks the chemistry and optical properties of garnets and the heavy mineral data show that low grade or contact metamorphic rocks such as skarns and hornfelses were widely exposed in the source areas of the permian triassic sandstones high grade metamorphic rocks including granulites and intrusive rocks appeared in early jurassic time and were widespread during the middle jurassic the critical change in the source areas for the southern kitakami terrane occurred during late triassic to early jurassic time and may correspond to the indosinian movements associated with the collision between the north china and south china blocks

major and trace elements in pyrope almandine garnets as sediment provenance indicators of the lower carboniferous culm sediments drahany uplands bohemian massif abstract the lower carboniferous culm basin is part of the european variscan foreland basin garnet is an abundant heavy mineral at all stratigraphic levels of the culm sediments the protivanov rozstani and myslejovice formation from base to top this paper compares the major element electron microprobe and trace element la icp ms compositions of garnet for the purpose of studying the provenance of the culm sediments the polymict garnet assemblages ranging from the protivanov to lower part of the myslejovice formation goniatite zones pe go pass into oligomict ones dominated by pyrope almandine garnets uppermost part of the myslejovice formation goniatite zones go go as the predominant low grossular pyrope almandines from oligomict garnet assemblages are very uniform and homogeneous in major element composition we studied their trace element composition and zoning pyrope almandine garnets are poor in lree and show enrichment in hree the chondrite normalized patterns are almost flat from dy to lu and show a significant negative eu anomaly typical for granulite grade garnets major element compositions of detrital low grossular pyrope almandines can only be matched with some granulites and garnetiferous felsic gneisses of the bohemian massif garnets from granulites cropping out at the present day erosion level of the bohemian massif have usually higher ca and or lower mg contents the major and trace element compositions and zoning patterns of pyrope almandine garnets from the upper part of the myslejovice formation compare well with garnets from the miroslav granulites and small moldanubian granulite bodies west of the t ebic massif the moldanubian granulites are commonly associated with mantle derived peridotites and eclogites the presence of detrital cr spinels with high cr and low mg single grains of cr spinels and fine grained kelyphitic intergrowths of cr spinel with chlorite comparable with spinel types from moldanubian peridotites could indicate the joint occurrence of peridotites serpentinized peridotites and granulites at the erosion level of the bohemian massif during the deposition of the uppermost culm sediments 325 ma while the older culm sediments polymict garnet assemblages represent the accumulation of clastic material from the northern and north western areas moravo silesian and lugian zone the uppermost culm sediments oligomict garnet assemblages contain material from western and south western areas moldanubian zone and moravian nappe the general influx of clastic material changed as a result of clockwise rotation of the eastern part of the variscan belt during this time span 340 325 ma

soil micromorphological evidence from iron age land use at tornby and mortlosa in linkoping sweden abstract the area of linkoping sweden has a land use history of several millennia in the last two decades many archaeological investigations of different types have been conducted here they range from trial trenching to full scale excavations of large areas and are connected to the expansion of the city the early iron age landscape of the area was formed by animal husbandry and the requirements of the domesticated animals earlier research has revealed an intensification and specialization within animal husbandry in the region occurring around the birth of christ when farms seemed particularly to specialize towards milk production however this transition and its local variations is still poorly investigated arable farming is assumed to have been characterized by small intensively used and improved cultivated areas close to the settlements but there are many questions still to be answered about the specific soil management types and crops there is a need to further investigate the land use history of the area from the early iron age 2440 2010 bp until medieval times ad 1030 1536 as part of the archaeological excavations carried out by the swedish national heritage board in 2007 six samples from three localities all in the linkoping municipality were chosen for soil micromorphological analysis at the locality of tornby i traces were found of anthropogenic activities including some kind of building activities prior to a period with extensive cultivation activities nearby presumably when the settlement was established in the pre roman iron age ca 200 bc it was followed by a period with soil management on the locality interpreted as a kind of garden cultivation the locality of tornby ii was presumably used a pasture in an early period and as a cultivation field with soil improvement in a later period at the locality of mortlosa dated to the roman iron age 2010 1680 bp and the migration period bc ad 550 ad traces from two different contemporary activity areas could be differentiated within few meters of a profile a cultivated field which has been improved with different kinds of manure through time and presumably a pathway for animals

provenance and tectonic setting of carboniferous triassic sandstones from the karaburun peninsula western turkey a multi method approach with implications for the palaeotethys evolution abstract carboniferous triassic siliciclastic sediments of the karaburun peninsula in western turkey were studied to unravel their provenance and the tectonic setting of depositional basins within the palaeotethyan realm a set of complementary techniques including petrography bulk rock geochemistry and single grain analysis of rutile garnet and chrome spinel were applied to provide a diverse dataset for testing existing palaeotectonic models using both established and recently published diagrams we show that tectonic discrimination diagrams of siliciclastic sediments based on major and trace element whole rock geochemical data do yield ambiguous results and are only partly in accordance with regional geological events chondrite normalised ree patterns of upper palaeozoic samples are characterised by enrichment of lree and a flat trend towards hree the degree of fractionation allows for discrimination between sandstones of karaburun lan ybn 8 00 14 79 and adjacent greek islands of chios 5 82 9 23 and inousses 7 40 9 95 petrographic observations and compositional data from single grain analysis indicate significant supply from low to medium grade metamorphic rocks of generally felsic character and minor input of ultra mafic detritus detrital chrome spinels in the lower triassic gerence formation are different in composition and shape compared to chrome spinels in carboniferous permian sandstones they were derived from a very proximal source and exhibit variable but generally high cr and mg numbers consistent with chrome spinels from podiform chromitites that have been formed in an intra oceanic back arc setting above a supra subduction zone we conclude that most of the carboniferous triassic successions were deposited along the southern active margin of eurasia in a continental arc environment during the time period when palaeotethys diminished in size and finally vanished large volumes of detritus were probably derived from rock units located in the present day balkan region and the sakarya zone or equivalent successions that are not present anymore

new geochemical results indicate a non alpine provenance for the alpine spectrum epidote garnet hornblende in quaternary upper rhine sediment abstract the heavy mineral assemblage of late pleistocene to modern rhine river sediment in the upper rhine graben is dominated by garnet green amphibole and epidote this so called alpine spectrum has been taken to indicate an exclusive derivation from the alps and has hitherto been investigated with optical methods only we present the first single grain geochemical data set of garnet and amphibole from the upper rhine river and some of its main tributaries we use the new data to test the alleged alpine provenance in the rhine our results show that the provenance of garnet mostly pyrope rich almandine is grain size dependent particularly the pyrope content indicates that the 0 063 0 25 mm size fraction has an alpine provenance whereas 0 25 0 5 mm grains derived from the black forest and the vosges which flank the upper rhine graben they mainly comprise of paleozoic metamorphic and igneous rocks supplying a suite of heavy minerals similar to the alpine spectrum to the rhine river amphibole mostly mg hornblende has an increasing tio2 content from the south to the north of the graben which also indicates an input from the graben shoulders the new data indicate that the so called alpine spectrum of heavy minerals in rhine river sediment of the upper rhine derived to significant degrees from non alpine sources furthermore our results indicate a relatively uniform provenance for the rhine river system during the past 1 ma

grain size dependence of garnet composition revealed by provenance signatures of modern stream sediments from the western hohe tauern austria abstract heavy minerals are valuable indicators about the geological framework in the source area the heavy mineral garnet is one of the most widespread heavy minerals in orogenic sediments and its geochemistry provides important information about metamorphic conditions the application of heavy minerals and garnet geochemistry for sedimentary provenance analysis is tested for modern stream sediments collected along three rivers draining the eclogite zone and adjacent geological source units of the western hohe tauern area in the central eastern european alps for comparison with the stream sediments rock outcrops exposed in this area were also sampled the chosen area is very well investigated and provides an excellent place to constrain the relations between source rocks and sediment in first order drainages the influence of grain size is studied in detail by considering grain size fractions ranging from coarse silt to coarse sand 32 to 1000 m in all grain size fractions the heavy mineral assemblages are characterised to a variable extent by epidote zoisite garnet and green calcic amphibole in the smaller grain size fraction apatite is more frequent whereas in the coarser grain size fractions an increase of green calcic amphibole and garnet can be observed electron microprobe analysis of detrital garnet shows the dominance of almandine rich garnet stream sediments within and downstream of the eclogite zone show an increase of pyrope rich garnets interestingly in all samples grossular rich garnets are more frequent in the smaller grain sizes and pyrope rich garnets are more frequent in the coarser grain sizes this is controlled by the original finer size distribution of grossular in the source rocks rather than being a hydraulic effect the heavy mineral assemblages and garnet geochemical data reflect the geological setting of the study area hence confirming the general strength of these methods in sedimentary provenance analysis however the data underline strong grain size control on sediment composition including single grain compositional variations

mineralogy of the core yrd 1101 of the yellow river delta implications for sediment origin and environmental evolution during the last 1 9myr abstract in this study we report the high resolution heavy mineral records from a 200 30 m long borehole yrd 1101 on the northern coast of modern yellow river delta yrd covering the last 1 90myr the results show that the heavy mineral assemblages are dominated by epidote followed by hornblende garnet and hematite limonite in the yellow river yr sediments the content of hornblende is higher than the epidote and the epidote to hornblende ratios e h are lower than the core yrd 1101 the e h show two distinct lower values at depositional unit du 4 2 117 9 125 6 m and du 4 1 to du 2 13 5 99 3 m indicating the obvious influence of yr sediments the heavy mineral composition of du 5 is distinct from yr sediments and interpreted as the result from heterogeneous provenance of the adjacent ancient rivers while du 4 to du 1 resemble the upper middle reaches of the yr sediments the different sediment types mud sandy silt and silt of core yrd 1101 do not contain markedly different transparent heavy mineral assemblages in terms of concentration and mineral ratios no matter how sedimentary environment changes the ratios of epidote and hornblende show very stable values in du 4 1 and du 3 due to the influence of yr sediments the transparent heavy minerals such as hornblende epidote and other stable minerals which were relatively stable are controlled primarily by provenance while the sedimentary environment mostly influences the flaky minerals and the authigenic minerals this study provides evidence regarding the history of the lower reaches of the yr and yrd since the early pleistocene highlighting river s important role for the evolution of the western coast of the bohai sea bs

climate at the equilibrium line of glaciers the relationships between temperature precipitation and radiation on glacier equilibrium lines are investigated using 70 glaciers for which the mass balance and meteorological observations have been carried out for sufficiently long periods it is found that the characteristic climate at glacier equilibrium lines can be described using the summer 3 months temperature in a free atmosphere annual total precipitation and the sum of global and long wave net radiation all of these are measured at or very near the equilibrium line altitudes then it is shown how the shift of the equilibriumline will occur as a result of a climatic change finally the effect of the shift of the equilibrium line on the annualmean specific mass balance is analytically derived and compared with observations the present results make it possible to identify the altitudes in climate models where glacierization should begin and to evaluate the mass balance changes as a result of possible future changes in the climate

heavy mineral analysis and detrital u pb ages of the intracontinental paleo yangzte basin implications for a transcontinental source to sink system during late cretaceous time

provenance of deep water reservoir sandstones from the jubarte oil field campos basin eastern brazilian margin the provenance of the maastrichtian deep water reservoir sandstones from the jubarte oil field campos basin eastern brazil was studied using an integrated approach that included quantitative petrography conventional heavy mineral analysis garnet mineral chemistry and zircon geochronology the reservoirs are predominantly coarse poorly sorted sandstones with feldspathic composition derived from uplifted basement terrains the fourth and fifth order depositional sequences analyzed show no major variations in composition or in provenance through time however variations in apatite tourmaline presents potential to be used as a parameter for sandstone correlation within the field the composition of heavy minerals indicates derivation from high temperature and low to medium pressure aluminous metapelitic rocks from granites and subordinate mafic rocks derived from the cabo frio tectonic domain and the oriental terrain of ribeira orogen characterizing a supply route from sw to ne the low ztr index as well as the absence of low grade stable heavy minerals and of metasedimentary rock fragments suggest that by the end of cretaceous all supracrustal low grade terrains had already been totally eroded and that plutonic infracrustal rocks were exposed similarly to the present situation the integration of the compositional and textural aspects suggests a tectonically active source area located relatively close to the basin the active tectonic uplift of the basement terrains provided a large volume of coarse poorly sorted sediments carried directly from mountain streams and alluvial fans to deep water the high frequency shifts in apatite tourmaline values support a direct derivation of the deep water sandstones from adjacent alluvial systems with short but differential exposure to weathering the voluminous deposition of such coarse grained and immature turbidites under the general transgressive conditions of the maastrichtian indicates a tectonic rather than eustatic control on their deposition with important implications for the exploration of similar reservoirs in campos basin and in similar basins of eastern brazilian margin

a multivariate discrimination scheme of detrital garnet chemistry for use in sedimentary provenance analysis abstract garnet chemistry provides a well established tool in the discrimination and interpretation of sediment provenance current discrimination approaches however i suffer from using less variables than available ii subjective determination of discrimination fields with strict boundaries suggesting clear separations where in fact probabilities are converging and iii significant overlap of compositional fields of garnet from different host rock groups the new multivariate discrimination scheme is based on a large database a hierarchical discrimination approach involving three steps linear discriminant analysis at each step and the five major host rock groups to be discriminated eclogite a amphibolite b and granulite c facies metamorphic rocks as well as ultramafic d and igneous rocks e the successful application of statistical discrimination approaches requires consideration of the a priori knowledge of the respective geologic setting this is accounted for by the use of prior probabilities three sets of prior probabilities priors are introduced and their advantages and disadvantages are discussed the user is free to choose among these priors which can be further modified according to the specific geologic problem and the level of a priori knowledge the discrimination results are provided as integrated probabilities of belonging to the five major host rock groups for performing calculations and results a supplementary excel spreadsheet is provided the discrimination scheme has been tested for a large variety of examples of crystalline rocks covering all of the five major groups and several subgroups from various geologic settings in most cases garnets are assigned correctly to the respective group exceptions typically reflect the peculiarities of the regional geologic situation evaluation of detrital garnets from modern and ancient sedimentary settings of the western gneiss region norway eastern alps austria and albertine rift uganda demonstrates the power to reflect the respective geologic situations and corroborates previous results as most garnet is derived from metamorphic rocks and many provenance studies aim at reconstructing the tectonic and geodynamic evolution in the source area the approach and the examples emphasize discrimination of metamorphic facies i e temperature pressure conditions rather than protolith composition

stability of detrital heavy minerals on the norwegian continental shelf as a function of depth and temperature abstract petrographic analysis of 1931 thin sections from sandstones of pliocene to devonian age on the norwegian continental shelf indicate that the heavy minerals zircon tourmaline rutile apatite and spinel survive to depths exceeding 5000 m and to temperatures of around 200 c without showing signs of intrastratal dissolution on the other hand the maximum depth and temperature of occurrence for amphibole are 841 m and 40 c around 1500 m and 55 c for sphene when 0 5 km of probable uplift is taken into account 2231 m and 92 c for kyanite 2559 m and 95 c for epidote 2810 m and 109 c for staurolite and 4589 m and 175 c for garnet initial signs of garnet dissolution occur at around 2000 m depth and all garnets are partially dissolved at depths greater than 3500 m monazite is present down to 4858 m and 182 c and chloritoid to 3811 m and 149 c it is however uncertain whether this is due to the low number of samples deeper than 4858 m and to the rare occurrence of chloritoid or to intrastratal dissolution the same sequence of heavy mineral stability is found when volume of quartz cement is used as a proxy for time temperature exposure quartz cement is not found in samples containing amphibole or detrital sphene a maximum of a fraction of a percent quartz cement is found in samples containing kyanite up to 1 together with epidote up to 6 with staurolite up to 24 with chloritoid up to 25 with garnet whereas maximum values of 25 35 are present together with zircon tourmaline rutile patite spinel and monazite the sequence of persistence of heavy minerals versus depth found in this study is very similar to results from several previous studies although unstable heavy minerals survive to greater depths in very young and rapidly buried sandstones and there are some differences regarding the stability of sphene and epidote heavy mineral dissolution has created secondary pores and possibly has contributed to precipitation of kaolinite illite quartz and carbonates in the studied sandstones but these reactions are of very limited volumetric importance

the provenance of triassic continental sandstones from the beryl field northern north sea mineralogical geochemical and sedimentological constraints a geochemical study of the heavy mineral suite in triassic strata from two wells in the beryl embayment was undertaken in order to identify changes in provenance through the lewis formation detailed provenance studies also allow the reconstruction of paleodrainage patterns and aid in predicting facies distributions the heavy mineral assemblage in the lewis formation is dominated by almandine pyrope garnets which are typically derived from pelitic metasediments together with zircon apatite tourmaline and rutile some of which are rich in niobium nb these latter phases could have been sourced either from metasediments or granitic protoliths although nb rich rutiles have a more restricted paragenesis being associated with alkaline plutonic rocks and granite pegmatites in the uppermost members of the lewis formation influxes of more exotic provenance specific heavy minerals such as cr spinel staurolite and chloritoid become more common the chemistry of the detrital cr spinel implies that it was derived from an ophiolitic source gross grain size and facies changes in the embayment suggest a nw to se dispersal of detritus although hydraulic sorting of the heavy mineral suite between relatively distal and proximal locations has resulted in subtle variations in whole rock trace element geochemical signatures the complete overlap in the geochemical data from distal and proximal wells requires that the sediments were essentially derived from a single source area the combination of mineralogical sedimentological and geochemical data implies that the dominant source for these sediments was the devonian old red sandstone ors the shetland ophiolite and the underlying dalradian metasedimentary rocks of the shetland isles and the east shetland platform provenance studies such as this are central to the reconstruction of paleo drainage patterns which in turn lead to improved prediction of potential reservoir quality distribution and connectivity

visible and near infrared reflectivity during the ablation period on peyto glacier alberta canada models for calculating glacier mass balance are sensitive to surface reflectivity variation fieldwork carried out on peyto glacier alberta canada contributes to the data set available for ice reflectivity parameterization in such models hemispherical reflectivity in the visible and near infrared parts of the solar spectrum was obtained for rock snow and three contrasting glacier surfaces to examine temporal and spatial variations glacier ice near infrared reflectivity displays only minor spatial variation 0 12 0 17 in comparison with the visible range 0 23 0 40 the latter being influenced primarily by surface impurity content surface roughness is of minor importance compared with impurities temporal variation of reflectivity was weak at all glacier ice and rock locations slight variations observed were due to changes in either solar zenith angle or cloud amount snow reflectivity displayed pronounced diurnal asymmetry and a larger response to cloud cover the minimal temporal variation in glacier ice reflectivity simplifies its parameterization this behaviour is additionally useful for satellite based measurements of the reflectivity field on larger glaciers as images obtained within a 6 h window centred on solar noon are likely to yield values which are within 2 3 of daily mean values

drowned coastal deposits with associated archaeological remains from a sea level slowstand northwestern gulf of maine usa drowned terrestrial wetland environments such as lakes marshes and beaches were thought to be rare in formerly glaciated regions like the gulf of maine united states in the northwestern gulf of maine postglacial relative sea level changes include a slowstand between 11 5 ka and 7 5 ka when the ocean rose 5 m this period of sea level stability permitted erosion of glacial materials and concomitant construction of spits and sheltered wetland habitats attractive to human occupation between 17 m and 22 m below modern sea level this work underscores the importance of a well constructed sea level chronology to predict the location of drowned terrestrial environments and associated cultural resources

the potential of detrital garnet as a provenance proxy in the central swiss alps abstract detrital garnet is a promising candidate to reliably fingerprint sediment sources in the alps which has so far been complicated by the wide range and similarity of some of the lithologies garnet is present in most alpine sediments is easy to identify is fairly stable and most importantly reflects the type and the metamorphic grade of its source rock in its chemical composition this study aims to establish fingerprints based on detrital garnet composition for the most important tectonic units of the central alps including european penninic and adriatic basement rocks and their respective metasedimentary covers sediments collected from modern rivers which drain representative portions of the individual tectonic units contain a natural mixture of the various garnet populations present in each unit we selected six catchments in southwestern switzerland draining the external massifs helvetic sediments and the penninic nappe stack at the transition of alpine greenschist to amphibolite facies metamorphism in order to test the variability of alpine garnets and the role of inherited pre alpine garnets extraordinary grossular and spessartine rich garnets of the external massifs which experienced greenschist facies metamorphism are clearly distinguishable from generally almandine rich garnets supplied by the higher grade metamorphic penninic nappe stack the variable pyrope grossular and spessartine components of these almandine rich garnets can be used to further distinguish pre alpine alpine eclogite facies and low grade metasedimentary garnets this provenance proxy has the potential to be used for reconstructing sediment sources transport and dispersal patterns in a variety of settings throughout the alpine sedimentary record

discrimination of density flow deposits using elemental geochemistry implications for subtle provenance differentiation in a narrow submarine canyon palaeogene danish north sea abstract elemental geochemistry of 1131 sandstone samples has been used to characterise five palaeogene sandstone members in a system of density flow deposits within an incised submarine canyon danish north sea diagenetic overprinting has complicated the use of most main and trace elements but a group of heavy mineral bound elements with low mobility ti y zr nb and th has proved highly potential for correlation the individual sandstone members exhibit very consistent relations between the heavy mineral elements along the canyon and based on zr ti plots two families of sandstone members can be distinguished the families are recognised on variations in inclination and intersection of linear regression lines which are related to subtle variations in provenance source area the inclination is believed to be controlled by the detrital heavy mineral hm suite and composition whereas the intersections are controlled by the background contribution such as hm inclusions in detrital rock forming minerals e g quartz and or feldspar as well as substituted and or adhered elements in glauconite the correlation pattern has been used to suggest a re interpretation of the stratigraphic relation of some of the sands

geochemistry and diagenesis of stratabound calcite cement layers within the rannoch formation of the brent group murchison field north viking graben northern north sea abstract up to four calcite cemented horizons doggers form impermeable barriers to fluid flow within the middle jurassic rannoch formation and are correlatable across the murchison field calcite precipitated during early diagenesis within high porosity permeability sandstones at the top of coarsening shoaling upward shoreface cycles calcite 13c and 18o compositions range from 4 1 to 13 4 pdb and 6 6 to 16 7 pdb respectively sr concentrations of up to 1334 ppm are consistent with marine carbonate sources probably shell fragments but no viable intraformational carbonate source has been identified in the murchison field area initial 87sr 86sr compositions 0 71109 0 71266 are higher than middle jurassic seawater 0 7073 and consistent with precipitation from modified porewaters containing significant proportions of continentally derived meteoric fluids enriched in 87sr as a result of basement weathering or percolation through hinterland soils unconsolidated detritus an internal source of 87sr is not considered viable in view of the high proportion up to 25 clastic constituents of unaltered detrital alkali feldspar and mica within the rannoch formation geochemical and isotope data indicate correlations between increasing 18o composition and increasing iron and magnesium content within calcite calcium concentrations decrease with increasing 18o for calcites geochemical data trends can be interpreted differently in terms of either static or evolving 18o porewater models static 18o porewater models using jurassic early cretaceous meteoric water 18 o 6 smow predict cement precipitation temperatures of 17 77 c however 13c compositions are more depleted than those typical of carbon derived from shell debris and correlation between decreasing 18o and decreasing 13c suggests modification of a meteoric derived porewater system during burial via contribution of low 13c carbon derived from a deep basinal source however it is difficult to constrain accurately the degree to which porewater 18o may have evolved during burial the degree to which porewater 18o could have evolved from that of a jurassic early cretaceous meteoric water can be loosely constrained as from 18 o 6 smow to 18 o 2 smow if the temperature at which the most 18o depleted cements precipitated is limited by present day bottom hole temperatures 110 c for wells currently at maximum burial depth

a distributed surface energy balance model for complex topography and its application to storglaciaren sweden a grid based surface energy balance mass balance model has been developed to simulate snow and ice melt in mountainous regions with an hourly resolution the model is applied to storglaciaren a valley glacier in sweden using a 30 m resolution digital elevation model emphasis is directed towards computing the radiation components these are modelled individually considering the effects of slope angle aspect and effective horizon a new parameterization for snow albedo is suggested modifying the albedo of the preceding hour as a function of time after snowfall air temperature and cloudiness the model is used to provide the meltwater input for discharge modelling and to assess the influence of the individual components on melt results are validated by means of observed melt rates patterns of snow line retreat and proglacial discharge in general simulations are in good agreement with observations in particular the diurnal and seasonal fluctuations of discharge are simulated remarkably well

provenance of late carboniferous sandstones in the pennine basin uk from combined heavy mineral garnet geochemistry and palaeocurrent studies abstract analyses of heavy mineral assemblages garnet geochemistry and palaeocurrent directions may each independently provide useful information on the provenance of sandstones but when such datasets are combined the number of options on the location of possible source areas can be greatly reduced also variations in heavy mineral signatures through a stratigraphical section can be explained in terms of switching between source areas rather than due to unroofing events in a single source area if palaeocurrent directions change at the appropriate levels likewise seemingly random changes in transport direction indicated by palaeocurrent variations through a short stratigraphical section can be shown by the heavy mineral data to be systematic and related to shifts between source areas illustrations of the mutual constraints provided by such combined datasets are drawn from late carboniferous successions of the pennine basin northern england where the contributions of detritus from several distinct source terrains and sediment pathways are well documented hallsworth c r morton a c claoue long j fanning c m 2000 carboniferous sand provenance in the pennine basin uk constraints from heavy mineral and detrital zircon age data sedimentary geology 137 147 185 chisholm j i hallsworth c r 2005 provenance of upper carboniferous sandstones in east derbyshire role of the wales brabant high proceedings of the yorkshire geological society 55 209 233 examples are given of how mineralogically distinct and geographically separated provenances can be identified how variations in heavy mineral suites can be used to identify whether variations in palaeoflow represent variations in provenance and how localised mixing recycling in incised channels can be inferred the final example defines the regional extent of the widespread northerly derived fluvial yeadonian sandstones and provides evidence for the mixing of more local sediment supplies at the basin margins

the experimental earthwork at wareham dorset after 33 years changes to the buried lfh and ah horizons this paper reports upon the effects of 33 years of burial upon the micromorphology chemistry and magnetic susceptibility of the topsoil of a lowland podzol buried beneath the bank of the experimental earthwork built at wareham dorset u k in 1963 the turf cored sand bank and associated ditch were constructed to replicate features of archaeological monuments found on acid heathland podzols as local soils were not fully recorded in 1963 unburied control profiles as well as turf and sand buried soils of the 1996 excavated section were studied the most marked changes affected the blfh horizon which was reduced from a likely maximum thickness of 70 mm to 1 4 mm a transformation already strongly established after only 17 years 1980 compression meso faunal mixing and incipient ferruginization accompanied decomposition and the transformation of an open plant tissue rich excremental fabric to a dominant amorphous form the bah was less obviously affected while the extent of organic decomposition in the buried soil cannot be established with certainty from organic c data continuing decomposition is indicated by a lowering of the c n ratio an increase in the pyrophosphate ext c organic c ratio an increase in alkali soluble humus and reductions in organic matter recorded in image analysis of thin sections especially in the sand buried soil major differences between the two burial environments sand and turf may result from the buried turf having a greater water holding capacity compared to the sands the moister environment more strongly inhibiting decomposition and activity by mesofauna compared to the sand buried soil this has led to greater transformations of void space and microstructure in the sand buried soil where the proportion of organ residues e g roots is the lowest roots being the easiest and most rapidly decomposed organic matter in the buried soil ph max and conv in the sand buried ah horizon rose probably due to the influence of overlying unweathered sands while and conv had become slightly diminished under the turf stack possibly as a result of weak gleying affecting the buried soil the higher moisture content here was also recorded by the formation of a coated and bridged welded microfabric in the turf stack and uppermost turf buried ah horizon these phenomena and processes such as continued leaching and podzolization are discussed in the light of some archaeological podzols at wareham continued leaching and podzolization led to a lossof k but an increased proportion of alkali soluble humus and pyrophosphate ext c in the bah horizon with a suggestion of incipient sesquioxide impregnation of buried plant materials e g blfh also being recorded

changes in detrital garnet assemblages related to transpressive uplifting associated with strike slip faulting an example from the cretaceous system in kii peninsula southwest japan abstract the chemical characteristics of detrital garnet have served as relatively reliable and definitive indicators of the major tectonic settings of sedimentary units in many parts of the world in southwest japan a multidisciplinary approach combining sandstone modal heavy mineral and garnet compositional analyses of the cretaceous upper continental slope to trench deposits of the kurosegawa and shimanto belts combined with a comparison of the detrital garnet features in and around kii peninsula revealed the following characteristics the garnet assemblages show significant changes with age the lower cretaceous yuasa formation is characterized by pyrope rich almandine garnets derived from granulite facies metamorphic rocks these are associated with garnet grains that have pyrope almandine compositions and high grossular contents suggesting an eclogite origin garnet assemblages of the lower upper cretaceous yukawa formation are dominated by grains with chemical characteristics indicating an origin as low p t type metamorphic rocks there are also spessartine almandine garnets derived from acidic igneous rocks some with a high p t type metamorphic origin and others with a grandite composition garnet assemblages of the upper upper cretaceous miyama formation are similar to those of the yukawa formation with the exception that grandite garnets are absent the above compositional changes of garnets in the deposits allow us to characterize the corresponding provenances and by combining these results with stratigraphic ages temporal changes of these provenances can also be determined the source area for the granulite facies metamorphic rocks that continuously supplied detritus throughout the cretaceous might be precambrian continental basement in east asia in early late cretaceous time the detritus was derived from terranes distributed along the median tectonic line a major strike slip fault stretching throughout southwest japan the garnet compositions suggest the source area included eclogite in the kurosegawa belt that forms the basement to the cretaceous strata and the low p t type metamorphic rocks and granitic rocks in the paleo ryoke belt including the higo belt studies of the miyama formation show that at this time widespread acidic volcanism began and this was the source for much of the volcanic sediment in the formation the provenance change between the lower and lower upper cretaceous formations is likely to have been caused by uplifting and unroofing associated with cretaceous transpression expressed by the strike slip movement along the median tectonic line and other lateral faults in the chichibu belt

reliability and application of detrital opaque fe ti oxide minerals in provenance determination a survey of detrital opaque fe ti oxide minerals in holocene sands derived exclusively from known source rocks in the rocky mountains usa semi arid climate high relief and the appalachian mountains usa humid climate low relief shows that despite obvious differences in weathering rates the abundance of detrital ilmenite relative to parent rocks is similar in these two regions because ilmenite is very common in many crystalline rocks ilmenite is considered to be a useful fe ti oxide mineral for varietal studies about 30 to 50 of detrital fe ti oxide minerals are polymineralic grains with intergrowths of two or more phases discriminant function analysis indicates that morphological varieties of detrital fe ti oxide minerals in combination with their chemical compositions are useful guides to provenance an igneous or metamorphic source of 96 of the holocene samples is correctly identified by this method the method is used to determine the relative contribution of igneous and metamorphic source rocks to the sandstones of the part of the tertiary renova formation which was deposited within a dissected magmatic arc in southwestern montana usa a separate discriminant function is calculated using the chemical compositions of detrital ilmenite and morphological properties of detrital fe ti oxide minerals in rocky mountain holocene sands classification of detrital fe ti oxide minerals in renova sandstones using this function suggests that igneous and metamorphic rocks contributed 77 and 23 respect ively to the renova sandstones in this area

evaluation of garnet discrimination diagrams using geochemical data of garnets derived from various host rocks abstract this work is an attempt to evaluate six different garnet discrimination diagrams one binary diagram and five ternary diagrams commonly used by many researchers the mineral chemistry of detrital garnet is a useful tool in sedimentary provenance studies yet there is no clear cut understanding of what garnet type originates from which host lithology several discrimination diagrams exist for garnet showing distinct compositional fields separated by strict boundaries that are thought to reflect specific types of source rocks for this study a large dataset was compiled n 3532 encompassing major element compositions of garnets derived from various host lithologies including metamorphic igneous and mantle derived rocks in order to test the applicability of the various discrimination schemes the dataset contains mineral chemical data collected from the literature complemented with some new data n 530 from garnet bearing metamorphic and ultramafic rocks in austria and norway discrimination of the tested diagrams only works for a small group of garnets derived from mantle rocks granulite facies metasedimentary rocks and felsic igneous rocks for other garnet types the assignment to a certain type of host rock remains ambiguous this is considered insufficient and therefore the evaluated diagrams should be used with great care we further apply compositional biplot analysis to derive some hints towards future perspectives in detrital garnet discrimination