the medieval climate anomaly in the iberian peninsula reconstructed from marine and lake records abstract selected multi proxy and accurately dated marine and terrestrial records covering the past 2000 years in the iberian peninsula ip facilitated a comprehensive regional paleoclimate reconstruction for the medieval climate anomaly mca 900 1300 ad the sequences enabled an integrated approach to land sea comparisons and despite local differences and some minor chronological inconsistencies presented clear evidence that the mca was a dry period in the mediterranean ip it was a period characterized by decreased lake levels more xerophytic and heliophytic vegetation a low frequency of floods major saharan eolian fluxes and less fluvial input to marine basins in contrast reconstruction based on sequences from the atlantic ocean side of the peninsula indicated increased humidity the data highlight the unique characteristics of the mca relative to earlier the dark ages da ca 500 900 years ad and subsequent the little ice age lia 1300 1850 years ad colder periods the reconstruction supports the hypothesis of trouet et al 2009 that a persistent positive mode of the north atlantic oscillation nao dominated the mca

a record of soil loss from butrint southern albania using mineral magnetism indicators and charcoal ad 450 to 1200 mineral magnetic and charcoal analyses were carried out on two sections 0 6 km apart on the vrina plain at shen delli a suburb of roman butrint ancient buthrotum southern albania using a chronology developed by archaeomagnetic dating the two sections postdate roman archaeological structures on the site providing a sediment record between c ad 450 and 1200 environmental magnetic data were analysed using cluster analysis to interpret a consistent stratigraphic development between the two sections above the archaeo logical remains on the western side of the shen deli settlement marsh clay sedimentation started ad 450 500 contemporaneous with evidence of site occupation anthropogenic activity is evident from the high macro charcoal content which declines at ad 750 800 and may mark the end of settlement in the vicinity both sections show similar sedimentation rates which when extrapolated suggest that marsh growth to the present day levels would have been completed between about ad 1500 and 1600 from about ad 750 to 850 sedimentation continued consistently across the site with low microcharcoal input but an increasingly important pres ence of magnetic minerals including superparamagnetic magnetite associated with top soil input between ad 1050 and 1200 the input from magnetically enhanced topsoil had increased tenfold over 300 years earlier indicating that soil erosion was a major sediment source this marked increase in soil loss could be due either to different land management practices or to local deforestation whether this change in topsoil loss is linked to climatic changes associated with the beginning of the mediaeval warm period c ad 1000 1400 needs further investigation

lead mobilization during tectonic reactivation of the western baltic shield abstract lead isotope data from sulfide deposits of the western part of the baltic shield define mixing lines in the 206 pb 204 pb 207 pb 204 pb diagram lead from two types of sulfide deposits have been investigated 1 1 exhalative and volcanogenic deposits that are syngenetic with their host rocks 2 2 vein deposits the syngenetic deposits locally show a very wide range of lead isotopic compositions that reflect a variable addition of highly radiogenic lead while the vein deposits although they have radiogenic lead isotopic compositions exhibit only limited isotopic variations in different provinces of the shield both types of deposits fall on the same lead mixing array the slope of the lead mixing lines varies as a function of the age of basement rocks and the age of the tectonic event which produced the lead mobilization and therefore relates the source rock age with the age of lead mobilization calculated mixing ages fall into several short time periods that correspond either to orogenic events or to major phases of continental rifting the orogenic events are the ca 360 430 ma caledonian ca 900 1100 ma sveconorwegian and the ca 1800 1900 ma svecofennian orogenic cycles the rifting events correspond to the formation of the ca 280 ma oslo rift and the ordovician ca 450 ma graben system in the area of the present gulf of bothnia each mixing age indicates that lead was mobilized probably as a consequence of mild thermal disturbances and that the crust was permeable to lead migration the data show that the geographic distribution of sulfide deposits with highly radiogenic lead isotopic compositions coincides with old graben systems orogenic belts and orogenic forelands on the baltic shield the ages of vein deposits and their geographic distribution demonstrate multiple tectonic reactivation of the interior of the baltic shield in response to orogenic events at its margin

stable isotope records of late quaternary climate and hydrology from mediterranean lakes the isomed synthesis lake isotope records can be used to assess the spatial coherency of late quaternary climate change across the circum mediterranean region we place modern and palaeo data within a simple conceptual lake response model to show that the isotope hydrology of most mediterranean lakes has been influenced strongly by water balance even in those systems that are chemically dilute i e freshwater 18o data on biogenic and endogenic carbonates from 24 lake basins are used to reconstruct multi millennial scale trends since the lgm while it is difficult to make direct comparisons between lake records in terms of single climatic parameters coherent regional isotopic trends can be identified during glacial times mediterranean lakes deposited carbonates isotopically heavier in 18o compared to the holocene partly due to source area effects isotopic enrichment was most marked during intervals corresponding to the h1 and younger dryas events confirming that late pleistocene cold stages in the north atlantic region were marked by aridity around much of the mediterranean almost all mediterranean lake records shifted to more depleted isotopic values during the last glacial interglacial transition lgit this shift is the reverse of the trend which characterised the same transition in lakes from northern and central europe and suggests that temperature changes were not an important direct driver of mediterranean lake isotopic records over glacial interglacial timescales in the early holocene many lakes in the eastern part of the region were more depleted isotopically than in recent millennia this corresponds with marine sapropel formation both chronologically and geographically and implies that increases in local rainfall contributed significantly to the creation of a freshwater lid and anoxia in the east mediterranean sea in contrast no such pattern is currently apparent from lake isotope records from the west mediterranean suggesting a possible nw se contrast in climate history during the holocene

multiproxy record for the last 4500 years from lake shkodra albania montenegro a multi proxy record is presented for approximately the last 4500 cal a bp from lake shkodra albania montenegro lithological analyses c n ratio and d 13 c of the organic and inorganic carbon component suggest that organic matter and bulk carbonate are predominantly authigenic the d 18 o record of bulk carbonate indicates the presence of two prominent wet periods one at ca 4300 cal a bp and one at ca 2500 2000 cal a bp the latter phase is also found in southern spain and central italy and represents a prominent event in the western and central mediterranean in the last 2000 years four relatively wet intervals occurred between ca 1800 and 1500 cal a bp 150 450 ad 1350 1250 600 700 ad 1100 800 850 1150 ad and at ca 90 cal a bp 1860 ad between ca 4100 and 2500 cal a bp d 18 o values are relatively high with three prominent peaks indicating drier conditions at ca 4100 4000 cal a bp ca 3500 and at ca 3300 cal a bp four additional drier events are identified at 1850 ca 100 ad 1400 ca 550 ad 1150 800 ad and ca 750 cal a bp 1200 ad the pollen record does not show changes in accordance with these episodes owing to the poor sensitivity of vegetation in this area which is dominated by an orographic rainfall effect and where changes in altitudinal vegetation belts do not affect the pollen rain in the lake catchment however since ca 900 cal a bp a significant decrease in the percentage arboreal pollen and in pollen concentrations suggest major deforestation produced by human activities copyright 2012 john wiley sons ltd

uranium mineralization in response to regional metamorphism at lilljuthatten sweden analyses of six mineralized and five nonmineralized whole rock drill core samples from the uranium deposit at lilljuthatten yield a lead lead isochron age of 420 or 1 m y this age corresponds to the last stage of the caledonian orogeny none of the isotopic systems examined have completely retained the intrusive age of the olden granite but data for several systems suggest an age of approximately 1 650 m y indications that caledonian hydrothermal activity strongly affected most of the olden granite a model for the genesis of the ore deposit is proposed as follows 1 derivation of a highly evolved granite by partial melting of crustal materials about 1 650 m y ago 2 pervasive hydrothermal alteration and fracturing of the granite in response to the caledonian orogeny approximately 420 m y ago 3 mobilization of uranium and lead in response to circulation of heated fluids 4 precipitation of these elements in open fractures and 5 recent modification of the caledonian uranium distribution as a result of exposure to near surface conditions modified journal abstract

geochemistry and petrology of the indium bearing polymetallic skarn ores at pitkaranta ladoga karelia russia the historic mining district of pitkaranta in the ladoga region fennoscandian shield was exploited for fe cu zn pb sn and ag in the nineteenth to twentieth centuries the pitkaranta region is dominated by palaeoproterozoic supracrustal rocks which together with gneissic archaean dome structures constitute an allochthonous terrane complex that amalgamated to the archaean continent during the svecokarelian orogeny at 1 9 1 8 ga this crustal complex was intruded by 1 8 ga late orogenic granites 1 54 ga anorogenic rapakivi granites and 1 45 ga dolerites the polymetallic skarn ores of pitkaranta extend over a 25 km long zone in palaeoproterozoic supracrustal rocks and formed from hydrothermal solutions which emanated from the anorogenic rapakivi granites and reacted with marble layers four major ore types are recognised after the dominating metal fe cu sn and zn respectively these types are not restricted to individual mines or mine fields but represent end members in zonation patterns within each ore body pitkaranta was the second discovery site in the world for indium but has been without modern documentation for more than 75 years the indium contents in the ores are up to 600 ppm in most cases sphalerite hosted the only roquesite bearing sample in this study had an indium grade of 291 ppm and an in zn ratio of 51 close to the criteria for the limiting conditions for creating an in rich mineral the pitkaranta ores have a potential for future small scale exploitation but all such plans are hampered by high contents if bi cd and as

the source of lead in the osen sandstone lead deposit on the baltic shield norway the sandstone hosted lead deposits on the baltic shield occur in marine late precambrian to early cambrian sedimentary rocks a ground water model in which the basement is postulated as the metal source has been proposed for these deposits to test this model the osen deposit was selected because it lies directly on a homogeneous granite basement on the basis of u th pb whole rock isotopic analyses for three samples of unweathered basement granite trysil granite a basement age of 1 598 m y was established the lead isotopic compositions of four out of five specimens of galena from the osen deposit plot between isochrons calculated for the granite at 500 m y and 540 m y this is strong support for the hypothesis that the lead source was basement granite and suggests that mineralization took place soon after sedimentation a basement source for the lead is further substantiated by the regional pattern of lead isotopic compositions of sandstone lead deposits which reflects the character of adjacent basement terranes

biogenic silica deposition in lake malawi east africa over the past 150 000years abstract we report a 150 000 year record of the abundance of biogenic silica bsi in drill cores from the northern and central basins of lake malawi the periods of highest diatom burial at both sites occurred around 65 69 and 51 60 thousand years ago ka after the termination of prolonged intense drought in the region these peaks are believed to reflect elevated delivery of dissolved silica to the lake due to acceleration of chemical weathering in the drainage basin the droughts that preceded these bsi depositional episodes occurred at precessional frequency corresponding to times of minimum austral spring or summer insolation in the region prior to 60 ka subsequent arid spells have not been as severe due to the reduced amplitude of precessional forcing as a result of the superimposed effect of eccentricity however biogenic silica records do not show significant sensitivity to precessional forcing the bsi burial flux in the north basin displays strong millennial scale variability since 50 ka with peak values occurring during cold times in the northern hemisphere as reflected in the greenland ice core records we observe no relationship between bsi and deposition of volcanic tephras in this system the central basin core also displays millennial scale variability in bsi abundance during the past 50 ky of comparable magnitude to that in the north basin but without systematic correlation to the north basin bsi or greenland ice core records in general we conclude that bsi profiles from the north and probably south basins are more readily interpreted in terms of regional climate dynamics than are bsi profiles from more central locations in long narrow tropical rift lakes diatom burial rates are suspected to be too influenced by silica limitations imposed by diatom production and burial in the upwelling systems at either end of these low latitude lacustrine systems

reconstructing past climates using carbon isotopes from fulvic acids in cave sediments little is known about the potential of organic substances found within cave sediments to provide useful reconstructions of past climatic changes here we present a study of the carbon isotopes of fulvic acids extracted from sediments from a cave in west central florida fulvic acids are the most contemporaneous representation of soil humic substances derived from vegetation growing above the cave radiocarbon dating of these sediments constrains their depositional period to be late holocene the range of the fulvic acid 13c record shows the dominance of c3 vegetation during this period but with changes in abundance and the shifting presence of c4 plants the 13c values record both the little ice age and medieval climate anomaly which produce drier and wetter conditions for florida respectively our conclusion that the stable carbon isotopic values of the cave sediment record as a proxy for vegetation change as driven by variability in precipitation is strongly supported by a comparison with the 13c and 18o values of two uranium series dated speleothems from this part of florida with both being proxies for precipitation change

human influence and the changing geomorphology of mediterranean deltas and coasts over the last 6000 years from progradation to destruction phase the present geomorphology of the mediterranean s coasts is largely a product of an intricate long term relationship between nature and human societies a cradle of ancient civilisations the mediterranean has seen its shores occupied by humans since prehistory and is therefore a particularly pertinent unit of analysis the morphotectonic context and other forcing agents e g climate shaped out a highly diversified coastal morphology and generated a sediment supply regime potentially favourable to the formation of numerous open coast deltas and bay head deltas in infilled rias as sea level stabilised during the mid holocene this supply of riverine sediment has also been the key agent in mediating human occupation of the mediterranean s clastic coasts expressions of this relationship have been extensively archived in clastic coastal deposits including base level deltaic and estuarine sedimentary sinks which comprise records to explore the interactions between geosystems and the human environment the stratigraphic sequences in these coastal sedimentary archives comprise in many places a clearly identified anthropogenic signature notably in ancient harbours some of which underwent extremely rapid silting up due to massive sediment sourcing generated by new agricultural practices from the neolithic onwards increasing human influence especially over the last 3000 years has been in turn an important driver of changes in sediment supply strongly modulating deltaic development pulses of sediment supply from catchments rendered vulnerable by human perturbations during the roman period resulted in a new cycle of inception of many other deltas and in rapid delta growth e g the ebro the po the arno and the ombrone another progradation dynamic during the little ice age at a time of strong rural population growth river discharge increases technological developments and urbanisation further consolidated delta growth understanding the life cycle of these deltas since their initial formation is in turn key to unravelling the relative role of natural and anthropogenic forcing agents rapid climate changes are deemed to have contributed through both the stripping of landscapes rendered fragile by human activities and active fluvial sediment transport to the coast but disentangling climate change effects from human impacts in the mediterranean remains a challenge the patterns of subsequent deltaic growth and delta morphodynamics reflect adaptations to pulsed sediment supply river discharge variations the microtidal fetch limited context of the mediterranean and direct engineering interventions the progradation dynamic of the roman period and little ice age contrasts markedly with the situation of common coastal destabilisation over the last two centuries particularly well documented for the last 50 years this period has been characterised by reduced sediment flux to base level geosystems due to catchment reforestation retenion within reservoirs fluvial regulation and dredging resulting in the erosion of deltas and barrier lagoon and beach dune systems large stretches of shoreline and narrow coastal plains have been massively engineered for coastal defence and protection against erosion but also for the construction of marinas leisure harbours and artificial beaches resulting in the emergence of veritable artificial seafronts these interventions have collectively and progressively raised societies to a pervasive and overarching position in the geomorphic stability instability of the mediterranean s coasts a situation that will be exacerbated by pressures from sea level rise paving the way for rampant coastal erosion and delta destruction

magnetosusceptibility event and cyclostratigraphy method applied to marine rocks detrital input versus carbonate productivity magnetic susceptibility data from marine rocks can be used for global correlation due to synchronous variations in global erosion we show here that the magnetic susceptibility signature found in two forms resides mainly in paramagnetic and other detrital constituents in most marine rocks the first form is a short term low magnitude high frequency cyclic climate signature that is often useful for regional correlation the second form is a longer term higher magnitude low frequency signature resulting from transgressive and regressive events that can be used for global correlation fluctuations in detrital input due to eustatic based erosion are the primary cause of events these fluctuations are driven by large scale processes such as global orogenic cycles however variations in carbonate productivity cannot be ruled out when explaining the low magnitude climate driven cyclicity also observed in magnetic susceptibility data sets

paragenetic zoning and genesis of cu zn fe pb as sulfide skarn ores in a proterozoic rift basin gruvaasen western bergslagen sweden silicate sulfide and oxide assemblages indicate three stages of alteration and mineralization during stage 1 potassic alteration and zonal precipitation of sulfides occurred basic sills and dikes close to the ores underwent strong potassic alteration and slight sulfide mineralization and were altered to skarn metatuffites underwent potassic alteration and sulfide mineralization and were altered to skarn and dolomitic limestones underwent dedolomitization and sulfide mineralization and were altered to skarn during stage 2 the potassically altered tuffites were replaced by infiltrational metasomatic amphibole skarns which were subsequently replaced by pyroxene forsterite skarns at temperatures of about 550 degrees c the late stage 2 pyroxene skarns are reaction skarns that are largely synkinematic with respect to boudinage of sulfide skarn layers and development of foliation in the marbles amphibole and pyroxene skarn relationships suggest a telescoping effect during the formation of the skarns silicate assemblages in metatuffites indicate metamorphic pressures of about 2 5 kb during stage 3 retrogressive alterations crystallization of pyrite and remobilization of sulfides occurred largely syn to postkinematically with respect to boudinage modified journal abstract

climate environment and society in southern italy during the last 2000 years a review of the environmental historical and archaeological evidence abstract this paper examines the interrelationship between the natural and human history of sicily over the last 2000 years it presents a close comparison of the data from the key multi proxy site of lago di pergusa located inland in the eastern part of sicily with the existing archaeological and textual evidence on the socio economic processes the article also includes a review of the available natural proxy archives from the central mediterranean on the basis of the isotope and pollen data from the lago di pergusa core prg2 we identified two humid periods ca 450 750 ad and ca 1400 1800 ad as well as a dry one ca 1100 1350 ad our evidence corresponds closely with other environmental palaeoclimate proxies from the mediterranean region in our synthesis of the environmental historical and archaeological evidence from southern italy we argue that during both periods of increased humidity that is during the late antique byzantine times and during the late medieval and early modern periods intense agricultural use of the sicilian landscape developed on an unprecedented scale this in turn contributed to the impressive demographic and economic expansion visible during these periods a sudden period of aridity followed the first of these eras of humidity related agricultural growth this climatic shift dated to around 750 ad corresponds to a decrease in synanthropic taxa and a recovery of arboreal vegetation we argue that in this case a climatic change contributed to socio economic decline moreover as this change occurred prior to the arab invasion of sicily in ad 827 the environmental processes may help to explain the collapse of byzantine society on sicily which in turn made the muslim conquest possible after this event there occurred a longer period of agricultural decline lasting until around 1000 ad after which we see the first signs of a slow recovery ongoing research in nearby archaeological sites will help defining if it was a local change or a regional potentially climate induced phenomenon although textual evidence records considerable population losses during the later middle ages as a result of the black death the effects of the plague are not obviously apparent in the pollen data except for some short term fluctuations

new lead isotope determination from five proterozoic sulfide deposits skellefte district sweden lead isotope analyses of 25 sulfide samples galenas iron sulfides and sulfosalts from five different mines of the skellefte district northern sweden demonstrate that the pb isotopic composition of galenas and other sulfides rich in lead varies between individual deposits within the district this contrasts with many other base metal districts where ore lead is isotopically homogeneous on a regional basis although all of the skellefte leads are depleted in 207pb relative to average global lead evolution models thus suggesting a large mantle derived component in their sources the nasliden deposit lying at the contact of the host volcanic rocks and the overlying metasediments contains a significant component of crustal lead it is concluded that while the pb isotope data are consistent with a volcanic exhalative origin of the ores of the skellefte district they also demonstrate that older crustal lead was incorporated into the sulfides during their emplacement and the subsequent period of magmatic and metamorphic activity which followed their deposition

age and geochemistry of granites associated with momineralizations in western bergslagen sweden abstract the bergslagen area south central sweden where large amounts of fe cu zn pb au ag mo and w have been produced for several centuries is one of the oldest mining districts in europe two episodes of magmatism and ore formation can be distinguished 1 an older early svecofennian phase that generated 1890 1850 ma old calc alkaline continental margin volcanic and plutonic units related to the svecofennian orogeny and 2 a younger phase comprising potassiumrich granitoids which intruded over a period extending from 1825 to 1680 ma during the final stage of or subsequent to the regional metamorphism and deformation related to the svecofennian orogeny in recent years considerable confusion has dominated the discussion concerning the timing and setting of the mo w forming granites in western bergslagen in this study one of the most important intrusions of undeformed granite in western bergslagen has been investigated in regard to geochemistry and u pb zircon age the granite skalhojden has a peraluminous silica and potassium rich chemistry as well as a uniformly flat ree pattern with a marked negative eu anomaly the u pb data yielded an age of 1758 8 ma these data show convincingly that the granite is comparable to other 1800 1680 ma mo w bearing granitoids elsewhere in the fennoscandian shield but are in strong conflict with hypotheses on early svecofennian rift related crust and ore forming processes recently proposed for western bergslagen a revision of the models of crustal growth and ore formation in that area is suggested

palaeogeographical reconstructions of lake maliq korca basin albania between 14 000 bp and 2000 bp since the early 1990s excavations of a protohistoric lakeside settlement in the korca basin carried out by a french albanian archaeological team have induced geomorphological and palynological studies about the sedimentary records of lake maliq these studies allow us to distinguish a series of centennial scale high and low lake level events between 4200 and 4000 cal bp 2899 2637 bc 2843 2416 bc and 2600 cal bp 822 671 bc probably due to large scale climate changes in the mediterranean basin in addition the sediment sequence also gives evidence of a millennial scale trend of lake level rise it appears to be an interplay between lake level rises and falls against tectonic subsidence of the basin allowing accommodation space for sediment deposition the variations of the lake s level and the lake s surface area influenced the development and the abandonment of the nearby lakeside settlements like the tell of sovjan in order to prepare an archaeological survey around the now dried up lake we made a 3d model of the holocene deposit from the lake including these lake level results geomorphological mapping excavation data numerous core logs ams 14 c dating and srtm dem data the gis model allowed us to propose four palaeogeographical reconstructions of the extension of lake maliq around 14 000 bp during the mesolithic around 9000 bp 8781 8542 bc the early middle bronze age transition around 3800 bp 2310 2042 bc and the iron age 2600 bp 822 671 bc a map of the thickness of the sediments above potential archaeological layers is also proposed

geology geochemistry age and geotectonic evolution of the dala granitoids central sweden abstract the dala granitoids and their associated volcanic products are part of a major palaeoproterozoic igneous complex the 1 85 1 67 ga transscandinavian igneous belt tib in the fennoscandian shield tib constitutes the south western border of the svecofennian domain which was formed by an orogenic episode at 1 93 1 83 ga earlier plate tectonic models proposed that tib is a postorogenic batholith complex which was formed in a compressional tectonic regime representing an andino type environment whereas an extensional tectonic regime has been proposed for the anorogenic 1 65 1 51 ga rapakivi granites in the svecofennian domain in this paper a key segment of tib the dala granitoids is discussed in order to focus attention on the post to anorogenic magmatic evolution in the svecofennian domain three types of granitoids jarna siljan and garberg can be distinguished within the dala granitoid complex the jarna granitoids are the most primitive and were emplaced at a significant depth in the crust at ca 1 79 ga the 1 70 1 68 ga siljan and garberg granites are more evolved and were emplaced at a shallow level in the crust closely associated in space time and origin with the volcanic dala porphyries field relationships as well as geochemical and geochronological data indicate magma genesis within a compressional tectonic regime for the 1 79 ga jarna granitoids however most of the dala granitoids appear to have formed in an extensional tectonic regime which was initiated during the last phase of tib magmatism this extensional igneous component is represented by the 1 70 1 68 ga high level siljan and garberg granites and their closely associated volcanic products the dala porphyries an improved model for the formation of the post to anorogenic magmatism in the svecofennian domain suggests that the dala granitoids represent a post to anorogenic igneous key complex which reflects the transition from a compressional to an extensional tectonic environment along a plate boundary

eastern mediterranean hydroclimate over the late glacial and holocene reconstructed from the sediments of nar lake central turkey using stable isotopes and carbonate mineralogy there is a lack of high resolution records of hydroclimate variability in the eastern mediterranean from the late glacial and early holocene more knowledge of the speed of climate shifts and the degree to which they were synchronous with changes in the north atlantic or elsewhere is required to understand better the controls on eastern mediterranean climate using endogenic carbonate from a sediment sequence from nar golu a maar lake in central turkey dated by varve counting and uranium thorium methods we present high resolution 25 years oxygen 18o and carbon isotope records supported by carbonate mineralogy data spanning the late glacial and holocene 18ocarbonate at nar golu has been shown previously to be a strong proxy for regional water balance after a dry period i e evaporation far exceeding precipitation in the younger dryas the data show a transition into the relatively wetter early holocene in the early holocene there are two drier periods that appear to peak at 9 3 ka and 8 2 ka coincident with cooling events seen in north atlantic records after this and as seen in other records from the eastern mediterranean there is a millennial scale drying trend through the mid holocene transition the relatively dry late holocene is punctuated by centennial scale drought intervals at the times of 4 2 ka event and late bronze age societal collapse overall we show that central turkey is drier when the north atlantic is cooler throughout this record and at multiple timescales thought to be due to a weakening of the westerly storm track resulting from reduced cyclogenesis in the north atlantic however some features such as the mid holocene transition and the fact the early holocene dry episodes at nar golu are of a longer duration than the more discrete events seen in north atlantic records imply there are additional controls on eastern mediterranean hydroclimate

middle east coastal ecosystem response to middle to late holocene abrupt climate changes the holocene vegetation history of the northern coastal arabian peninsula is of long standing interest as this mediterranean semiarid arid region is known to be particularly sensitive to climatic changes detailed palynological data from an 800 cm alluvial sequence cored in the jableh plain in northwest syria have been used to reconstruct the vegetation dynamics in the coastal lowlands and the nearby jabal an nusayriyah mountains for the period 2150 to 550 b c corresponding with the 4 2 to 3 9 and 3 5 to 2 5 cal kyr bp abrupt climate changes accs two large scale shifts to a more arid climate have been recorded these two accs had different impacts on the vegetation assemblages in coastal syria the 3 5 to 2 5 cal kyr bp acc is drier and lasted longer than the 4 2 to 3 9 cal kyr bp acc and is characterized by the development of a warm steppe pollen derived biome 1100 800 b c and a peak of hot desert pollen derived biome at 900 b c the 4 2 to 3 9 cal kyr bp acc is characterized by a xerophytic woods and shrubs pollen derived biome ca 2050 b c the impact of the 3 5 to 2 5 cal kyr bp acc on human occupation and cultural development is important along the syrian coast with the destruction of ugarit and the collapse of the ugarit kingdom at ca 1190 to 1185 b c

speleothem evidence for late holocene climate variability and floods in southern greece abstract we present stable isotope data 18o 13c from a detrital rich stalagmite from kapsia cave the peloponnese greece the cave is rich in archeological remains and there are reasons to believe that flooding of the cave has directly affected humans using the cave using a combination of u th and 14c dating to constrain a site specific correction factor for 232th 238u detrital molar ratio a linear age model was constructed the age model shows that the stalagmite grew during the period from ca 950 bc to ca ad 830 the stable oxygen record from kapsia indicates cyclical changes of close to 500 yr in precipitation amount with rapid shifts towards wetter conditions followed by slowly developing aridity superimposed on this signal wetter conditions are inferred around 850 700 500 and 400 100 bc and around ad 160 300 and ad 770 and driest conditions are inferred to have occurred around 450 bc ad 100 150 and ad 650 detrital horizons in the stalagmite indicate that three major floods took place in the cave at 500 bc 70 bc and ad 450 the stable carbon isotope record reflects changes in biological activity being a result of both climate and human activities

multi chronometric ages and origin of archaean tonalitic gneisses in finnish lapland a case for long crustal residence time the tojottamanselka gneisses of the koitelainen region northern finland have been dated by the sm nd and the common pb methods the sm nd data of seven samples from a small area 100 m 100 m define an isochron oft 3 06 0 12 2 ga with correspondingind 0 50848 9 2 orend t 3 7 1 8 this age is in good agreement with the zircon u pb discordia age 3 1 ga reported by kroner et al 1981 and is interpreted as the time of magmatic emplacement the distinctly negativeend t value is found for the first time for archean tonalitic gneisses and implies derivation of these magmas by remelting of continental material with a long 200 500 ma crustal residence time a few samples on the other hand possessend t values close to zero hence they are thought to be derived by partial melting of basaltic sources with nearchondritic ree distribution patterns

granites and early proterozoic crustal evolution in sweden evidence from smnd upb and o isotope systematics abstract u pb zircon and whole rock rb sr sm nd and o isotope results are reported for granitoids from three proterozoic provinces in sweden that represent different crustal environments the radiometric ages span the period 1 89 1 65 ga and record events ranging from original igneous crystallisation to late metamorphic resetting these events occurred at different times in the crustal segments the o isotope ratios identify different crustal source materials for the granitoids the sm nd results indicate that the major crustal source components common to most of the granitoids formed shortly before 1 9 ga close in time to the formation of the earliest granitoids contributions from recycled archaean basement are minimal the geographically widespread occurrence of such crustal sources indicates that the period around 2 ga was of great importance for the growth of new continental crust in sweden

metamorphic ore remobilization in the hallefors district bergslagen sweden constraints from mineralogical and small scale sulphur isotope studies the marble and metavolcanic hosted pb zn ag sb as deposits of the hallefors district located in the palaeoproterozoic bergslagen ore province south central sweden comprise both stratabound sulphides and discordant ag rich sulphide sulphosalt veins the complex sulphide sulphosalt assemblages of the alfrida jan olof mines at hallefors were investigated by a combination of ore microscopy electron microprobe analysis and in situ laser sulphur isotope analysis the massive ore is characterized by positive and homoge neous d 34 s 1 4 to 2 7 v cdt whereas vein hosted sulphides and sulphosalts exhibit similar but generally less positive to slightly negative d 34 s 0 6 to 2 0 comparison of the observed ore mineral assemblages with calculated phase equilibria in the sys tem fe as s o h and isotopic fractionation as a function of temperature oxygen fugacity and ph indi cates that the vein type mineralization was formed from relatively reduced and rather alkaline hydrothermal fluids at these reduced conditions fractionation of d 34 s via changes of fo2 is insignificant and thus the isotopic signatures of the vein minerals directly reflect the com position of the sulphur source we therefore conclude that the vein type ore essentially inherited the sulphur isotope signature from the pre existing massive sulp hides via metamorphic remobilization at approximately 300 400c and 2 3 kbar scales of remobilization observable are on the order of about 5 mm to 30 cm overall the sulphide sulphosalt assemblages from the alfrida jan olof mines exhibit d 34 s values which are comparable to a majority of metasupracrustal hosted deposits in the bergslagen province thereby suggesting a common origin from ca 1 90 1 88 ga volcanic hydro thermal processes

numerical modelling of water transport processes in partially connected tidal basins abstract in the paper two types of numerical models a lumped parameter model and a high resolution two dimensional hydrodynamic model are used to analyse the response of a system of partially connected tidal basins to inhomogeneous open sea forcing the equations of the lumped parameter model suitable for an arbitrary number of basins with sloping walls are formulated based on one dimensional continuity and momentum equations numerical solutions to the equations are thoroughly examined showing the influence of inhomogeneous open sea forcing and of geometrical parameters of the basins on the tidal range and the water transport through the system with particular emphasis given to inter basin water exchange and cumulative water transport through basins boundaries the results of the lumped parameter model simulations for the tidal basins of the german wadden sea are successfully compared with the results of calculations with the two dimensional hydrodynamic model which is used to investigate in more detail circulation patterns and the influence of specific local features of inlet bathymetry on the hydrodynamic processes in the study area the influence of wind on the basins response is discussed as well

the effect of climate change on the mobility and stability of coastal sand dunes in ceara state ne brazil the coast of ceara state in ne brazil is covered by vast fields of active and stabilized coastal sand dunes its tropical climate is characterized by two seasons wet and dry with wind intensity determined by the meridional shift of the intertropical convergence zone the wind power is negatively correlated with precipitation and precipitation is negatively correlated with the difference between sea surface temperatures of the tropical atlantic north and south of the equator we present a model suggesting that during the late pleistocene wind power determined the mobility and stability of the dunes sand dunes accumulated during periods of high wind power as it is today and stabilized when wind power was low once the dunes were stabilized by vegetation they could not be activated even by increased wind power samples that were taken for luminescence dating from 25 stabilized dunes along the coasts of ceara gave ages ranging from135 ka to 100 yr we postulate that these luminescence ages fall at the beginning of wet periods in ne brazil characterized by low wind power these paleoclimatic wet periods correlate well with the cold periods of stades in greenland ice core records

characteristics and geological setting of synkinematic svecokarelian granitoids in southern finland abstract synkinematic granitoids are the predominant component of the svecokarelian crust their zircon u pb ages vary from 1900 to 1860 ma mainly 1890 1870 ma being roughly similar to those of mafic plutonic rocks and metavolcanic rocks synkinematic granitoids occur as distinct plutons in schist belts and also form the granitold complex of central finland with a total area in excess of 35 000 km2 the granitoids in schist belts occur as concordant plutons although locally they have cross cutting contacts and they crystallized soon after the peak of major regional deformation and metamorphism but before younger deformation phases they are composed of granodiorites tonalites and trondhjemites composite plutons are often zoned with gabbro diorite tonalite and or trondhjemite at their margins and with granodiorite and less commonly granite at their centres the granitoid complex of central finland is composed of a vast number of intrusions ranging in composition from gabbro to granite the granite intrusions comprising large parts of the complex coarse grained granitoids and polyphase deformation are common major minerals of the synkinematic granitoids are plagioclase potassium feldspar quartz biotite and hornblende typical accessories are sphene apatite magnetite and zircon whole rock analyses of 143 granitoids from throughout southern finland show calc alkaline characteristics with variable sio2 high na2o k2o and a cnk below 1 1 initial 87sr 86sr ratios are low the granitoid complex of central finland has higher feo mgo and k2o na2o than the granitoids in schist belts irrespective of silica content the synkinematic granitoids have the geological and geochemical characteristics of phanerozoic i type granitoids and are cogenetic with mafic plutonic rocks intrusion of these latter evidently caused major remelting in the lower crust giving rise to granitoid magmas so that a variable mixing of mantle derived and crustal magmas is probable according to nd isotopes studies archaean material was insignificant in the source of the granitoids except near the border zone of the archaean craton this indicates rapid recycling of material newly derived from the mantle geochemical features of the granitoid complex may also reflect a thicker crust in central finland than in surrounding areas during the generation of the granitoids many characteristics of the synkinematic granitoids strongly suggest a subduction related origin however the similarity in isotopic ages and lack of obvious linear trends in distribution of rock types combined with evidence for a minor older crustal component in their source indicates that the processes were not identical to those operating at modern continental margins

origin of continental crust of 1 9 1 7 ga age nd isotopes in the svecofennian orogenic terrains of sweden initial nd isotopic ratios are reported for 57 samples representing all crustal components in the central and southern parts of the 1 9 1 7 ga old svecofennian orogenic terrains of sweden and the 1 8 1 7 ga old transscandinavian granite porphyry belt transscandinavian igneous belt u pb zircon ages are determined where the magmatic ages were not sufficiently constrained the nd isotopic results show that there are no archaean crustal blocks within the studied 1 9 1 7 ga old crustal segment this is consistent with results from finland the main input of recycled archaean crust to the svecofennian was in the form of sediments which are concentrated in the central svecofennian subprovince of north central sweden this is consistent with the vicinity of this subprovince to the archaean craton of the baltic shield these turbidite sediments contain up to 40 archaean material but s type granitoids associated with them have a smaller archaean component around 20 most of the quantitatively predominant i type granitoids and volcanics as well as all the basaltic rocks studied have nd from 1 to 3 and consist of 90 material newly derived from the mantle 1 9 1 7 ga ago we argue that the archaean material was introduced in the form of sediments but we cannot distinguish between pelagic sediments delivered on subducting oceanic crust and turbidite accumulations like the ones seen in north central sweden in either case an overall 15 archaean contribution for the swedish svecofennian was reasonably well homogenized with mantle derived magmatic products for this to occur an active near surface tectonic environment such as a complex of subduction zones must have been necessary

on the nonlinear helmholtz response of almost enclosed tidal basins with sloping bottoms short relatively deep tidal basins which are connected to the open sea by a narrow strait may exhibit either an amplified resonant or damped choked response to the tide at the entrance here particular attention is given to the lowest mode of response which is the helmholtz or pumping mode for which the sea level within the basin executes a spatially uniform oscillation when the basin s sidewalls slope the restoring process of this oscillator is nonlinear possible consequences of this nonlinearity are that the basin may exhibit either long lasting high waters and short peaked low waters or long term regular modulation of its tidal amplitude or a chaotic modulation of its tidal amplitude or bent resonance horns implying that resonant and choked tidal responses may exist simultaneously for the same parameter regime related field observations will be discussed

element concentrations and magnetic susceptibility of anthrosols indicators of prehistoric human occupation in the inland pilbara western australia the study of archaeological sediments is an important source of information on how humans lived at a site attributes of human site use such as frequency of visits and duration of stay can be explored by measuring changes in phosphorus determined using x ray fluorescence and carbon concentrations in sediments and magnetic susceptibility of sediments in combination with analysis of other sediment attributes stone artefacts and faunal remains this study concludes that increases in phosphorus and carbon concentrations and the discard rate of stone artefacts at marillana a rockshelter in the inland pilbara western australia indicate an increase in the frequency of site use with no change in the function of the site this is interpreted as representative of an increase in regional population density 2005 elsevier ltd all rights reserved

the effect of a topographic high on the morphological stability of a two inlet bay system abstract the cross sectional stability of two tidal inlets connecting the same back barrier lagoon to the ocean is investigated the condition for equilibrium is the cross sectional area tidal prism relationship in an earlier study van de kreeke j 1990 can multiple inlets be stable estuarine coastal and shelf science 30 261 273 using the same equilibrium condition it was concluded that where two inlets connect the same basin to the ocean ultimately one inlet will close one of the major assumptions in that study was that the water level in the basin fluctuated uniformly in hindsight this assumption might be too restrictive for example in the wadden sea the back barrier lagoon consists of a series of basins rather than one single basin separated by topographic highs these topographic highs limit but do not exclude the exchange of water between the sub basins for this reason in the present study a topographic high in the form of a weir was added separating the back barrier lagoon in two sub basins the water level in the sub basins rather than in the back barrier as a whole is assumed to fluctuate uniformly for this schematization the hydrodynamic equations are solved using a finite difference method the results together with the equilibrium condition yield the equilibrium flow curve for each of the inlets the intersections of the two equilibrium flow curves represent combinations of cross sectional areas for which both inlets are in equilibrium the stability of the equilibriums was investigated using a non linear stability analysis resulting in a flow diagram calculations were carried out for different inlet and weir characteristics sinussoidal tides were the same for both inlets the results show that for relatively large wetted cross sectional areas over the topographic high approaching the situation of a single basin there are no combinations of inlet cross sectional areas for which both inlets are in a stable equilibrium this supports the conclusion in the earlier study for relatively small wetted cross sectional areas over the topographic high there is one set of stable equilibriums in that case the two inlet bay system approaches that of two single inlet bay systems

the enasen gold deposit central sweden stable isotope analyses of quartz sulphides and magnetite were conducted to provide information on thermal history and source of hydrothermal fluids in the palaeoproterozoic enasen gold deposit reequilibration and homogenization of oxygen isotopes throughout the rock have apparently not occurred despite the upper amphibolite to granulite facies regional metamorphism that has affected the rocks however oxygen isotope geothermometry on a coexisting quartz magnetite pair gave a minimum temperature for peak metamorphism of around 650 c which agrees with fe mg geothermometry this suggests that grain scale equilibrium is achieved the variation in oxygen isotope ratios 18o 7 3 10 5 on quartz from the metamorphosed acid sulphate alteration zone is suggested to represent a cooling trend in the fossil hydrothermal system with higher 18o values in more superficial parts temperatures of alteration and silicification and isotopic composition of hydrothermal fluids could not be defined from the present data but it was recognized that the data is compatible with a epithermal genesis for the deposit it is suggested that alteration silicification and mineralization at the enasen gold deposit took place in a high sulphidation epithermal environment at temperatures of around 200 250 c and that the hydrothermal fluids consisted of meteoric and magmatic water a tentative reconstruction of the fossil hydrothermal system is presented sulphur isotope ratios of sulphides from the fold bearing quartz sillimanite gneiss gave 34s values close to zero indicating a magmatic source of the sulphur

high resolution paleoclimatic trends for the holocene identified using magnetic susceptibility data from archaeological excavations in caves abstract a proxy paleoclimatic curve has been produced for the holocene c 9000 3500 bp from magnetic susceptibility ms measurements of sediment samples collected from two dated archaeological excavation trenches in konispol cave albania the resulting ms data provide paleoclimate estimates that are in excellent agreement with independently published paleoclimatic trends for early middle holocene time basically ms variations are attributed to variations in climate controlled pedogenesis and the production of magnetic mineral phases including maghemite outside the cave these soils are then washed blown or tracked into the cave where they accumulate creating the ms changes observed in the samples recovered low ms magnitudes indicate times of cooler drier climate resulting from reduced pedogenesis while warmer wetter times yield higher pedogenetic rates and thus higher ms magnitudes it is clear from the konispol cave results that some caves provide ideal protected environments from which high resolution paleoclimatic records can be extracted composite sections from excavations within a single region can yield a relatively continuous long term climatic proxy that can be routinely correlated to artefacts recovered from these or other protected excavations within the same region

human climate interactions in the central mediterranean region during the last millennia the laminated record of lake butrint albania lake butrint 39 47 n 20 1 e is a ca 21 m deep coastal lagoon located in sw albania where finely laminated sediments have been continuously deposited during the last millennia the multi proxy analysis sedimentology high resolution elemental geochemistry and pollen of a 12 m long sediment core supported by seven ams radiocarbon dates and 137cs dating enable a precise reconstruction of the environmental change that occurred in the central mediterranean region during the last 4 5 cal kyrs bp sediments consist of triplets of authigenic carbonates organic matter and clayey laminae fluctuations in the thickness and or presence of these different types of seasonal laminae indicate variations in water salinity organic productivity and runoff in the lake s catchment as a result of the complex interplay of tectonics anthropogenic forcing and climate variability the progradation of the pavllo river delta favoured by variable human activity from the nearby ancient city of butrint led to the progressive isolation of this hydrological system from the ionian sea the system evolved from an open bay to a restricted lagoon which is consistent with archaeological data an abrupt increase in mass wasting activity between 1515 and 1450 bc likely caused by nearby seismic activity led to the accumulation of 24 homogenites up to 17 cm thick they have been deposited during the onset of finely laminated sedimentation which indicates restricted anoxic bottom water conditions and higher salinity periods of maximum water salinity biological productivity and carbonate precipitation coincide with warmer intervals such as the early roman warm period rwp 500 bc 0 ad the medieval climate anomaly mca 800 1400 ad and recent times after 1800 ad conversely lower salinity and more oxic conditions with higher clastic input were recorded during 1400 500 bc the late roman and the early medieval periods 0 800 ad and during the little ice age 1400 1800 ad hydrological fluctuations recorded in butrint are in phase with most central and western mediterranean records and correlate with nao variability in contrast opposite hydrological patterns have been recorded in the eastern balkans and the levant during the last millennium emphasizing a complex spatial variability in the region phases of maximum settlement intensity in butrint roman late antique coincide with warmer and or stable climate periods 0 800 ad and mca respectively indicating a long term influence of climatic conditions on human activities the late holocene sedimentary record of lake butrint demonstrates the complex interplay of climate variability tectonics and human impact in the recent evolution of coastal mediterranean regions

some new lead isotope determinations from the proterozoic sulfide ores of central sweden lead isotope determinations were made on galenas from three strata bound sulfide ores in the early proterozoic svecokarelian bergslagen district of central sweden and four epigenetic deposits in the alvdalen and vansbro districts in the early to middle proterozoic post svecokarelian belt the leads from the strata bound bergslagen deposits show exceptional isotopic homogeneity over large areas their isotopic composition suggests the existence of a pre svecokarelian crust in the district and is consistent with exhalative sedimentary ore formation in an active continental margin environment the vansbro and alvdalen leads display constant compositions within each district but marked divergence between the districts their compositions preclude derivation exclusively from recycled svecokarelian lead and suggest a substantial lead contribution from a mantle like source the difference between model ages and geologic ages for many of the deposits with a small but significant excess of radiogenic lead suggests a significant deviation of the fennoscandian shield from conventional global lead evolution models

geological geochemical and geochronological evidence for a new palaeoproterozoic terrane in southeastern sweden the geological and geochronological relationships between a rhyolite belonging to the transscandinavian igneous belt tib and an intrusive suite the backaby intrusion southeast sweden have been investigated by means of bedrock mapping geochemistry and radiometric age determinations u pb on zircons field relations suggest that the rhyolite rests unconformably on the backaby intrusion which previously has been correlated with 1 9 ga granitoids within the svecofennian domain the rhyolite yielded an age of 1800 8 ma and a tonalite belonging to the backaby intrusion basement yielded an age of 1834 3 ma the age of the rhyolite is slightly older 10 15 ma than adjacent granitoids belonging to the transscandinavian igneous belt and is considered as the earliest magmatic expression of tib in the area the age and the geochemical trends for the backaby intrusion is significantly different from that of the surrounding tib granitoids and indicate a rock forming event at about 1830 1840 ma in southeastern sweden represented by the oskarshamn jonkoping belt this event is significantly younger than the older svecofennian rocks within the svecofennian domain proper indicating a hitherto unidentified geological terrane in southeastern sweden

effects of a shallow flood shoal and friction on hydrodynamics of a multiple inlet system prior studies have shown that frictional changes owing to evolving geometry of an inlet in a multiple inlet bay system can affect tidally driven circulation here a step between a relatively deep inlet and a shallow bay also is shown to affect tidal sea level fluctuations in a bay connected to multiple inlets to examine the relative importance of friction and a step a lumped element parameter model is used that includes tidal reflection from the step the model is applied to the two inlet system of katama inlet which connects katama bay on martha s vineyard ma to the atlantic ocean and edgartown channel which connects the bay to vineyard sound consistent with observations and previous numerical simulations the lumped element model suggests that the presence of a shallow flood shoal limits the influence of an inlet in addition the model suggests an increasing importance of friction relative to the importance of the step as an inlet shallows narrows and lengthens as observed at katama inlet from 2011 to 2014

holocene climate variability and cultural evolution in the near east from the dead sea sedimentary record abstract a comprehensive record of lake level changes in the dead sea has been reconstructed using multiple well dated sediment cores recovered from the dead sea shore interpreting the lake level changes as monitors of precipitation in the dead sea drainage area and the regional eastern mediterranean palaeoclimate we document the presence of two major wet phases 10 8 6 and 5 6 3 5 cal kyr bp and multiple abrupt arid events during the holocene the arid events in the holocene dead sea appear to coincide with major breaks in the near east cultural evolution at 8 6 8 2 4 2 3 5 cal kyr bp wetter periods are marked by the enlargement of smaller settlements and growth of farming communities in desert regions suggesting a parallelism between climate and near east cultural development

metal sources in the early proterozoic svecofennian terrain of central sweden pb isotope evidence the lead isotope composition of three cu zn pb sulfide deposits and one au deposit in the early proterozoic svecofennian of central sweden reveals the existence of two distinct lead sources in the region rockliden and enstern contain lead of upper crustal affinity and are isotopically homogeneous lead in these deposits probably originates from archean derived detritus which was well homogenized by sedimentary processes and deposited over large areas as a component in early proterozoic sedimentary and tuffaceous rocks lead isotopic homogeneity within the tjarnberget and enasen deposits is less pronounced and the less radiogenic character of the lead suggests a source of mantle affinity in areas where metasedimentary rocks are absent or contain very little archean derived material the isotopic signature of mantle derived volcanic rocks is reflected in the ore lead this approach is also applicable to other svecofennian deposits together with deposits in west central finland the rockliden deposit constitutes the northern boundary for lead of upper crustal affinity i e archean derived lead in svecofennian sulfide deposits

lead isotopic evidence for the origin of 1 8 1 4 ga ores and granitoids in the southeastern part of the fennoscandian shield abstract new data for the lead isotopic composition of galena from ore deposits related to 1 8 1 4 ga granitoids in the southeastern part of the fennoscandian shield are presented and discussed together with earlier published information on granitoids and associated ore deposits two types of sulphide deposits genetically related to the granites can be recognized based on general metallogenetic features and isotopic composition granite hosted deposits including sn bearing greisen veins in rapakivi granites and peri intrusive deposits including contact metasomatic skarn deposits like pitkaranta and gruvasen in addition epigenetic deposits with a spatial but not a genetic link to the granites occur at various sites an important metallogenetic belt related to 1 7 1 5 ga granitoids can be followed in an east west direction across the shield from lake siljan in sweden to salmi at lake ladoga within this belt a major difference in metal derivation can be recognized ore deposits southwest of the raahe ladoga line i e in areas without archaean basement indicate metal derivation from remelted 1 9 ga svecofennian crust whereas ore deposits in areas underlain by archaean rock units indicate metal derivation from highly metamorphosed archaean sources

global correlation using magnetic susceptibility data from lower devonian rocks magnetic susceptibility data from marine rocks can be used for global correlation because of synchronous variations in global erosion we show here correlations between magnetic susceptibility data from two lower devonian biostratigraphically well defined sections one in northwestern spain and one from the anti atlas region of morocco using the moroccan outcrop section we correlate to cuttings from a bolivian well with minimal biostratigraphic control using the magnetic susceptibility data we identify the lower devonian pragian emsian and lower upper emsian stage boundaries in the bolivian well samples

the western border of the archaean province of the baltic shield evidence from northern sweden restricted areas of acid to intermediate gneisses in northernmost sweden are known to be archaean and several other gneissic granodioritic to tonalitic massifs have been suggested to be of this age to delimit the western border of the archaean province of the baltic shield and to characterize the swedish archaean we have studied the 2 83 ga old soppero gneiss and 8 of the proposed archaean massifs in northern sweden by sm nd isotopic analyses u pb zircon dating in two cases and geochemistry

tracing bottom water oxygenation with sedimentary mn fe ratios in lake zurich switzerland abstract redox dynamics of manganese mn were studied in the sediment of lake zurich using precise sediment core age models monthly long term oxygen o 2 monitoring data of the water column 1936 2010 and high resolution xrf core scanning the age models were based on bi annual lamination and calcite precipitation cycles if present mn exhibits distinct maxima which coincide with the annual maximum deep water o 2 concentrations in spring according to the monitoring data in contrast the iron fe signal is mainly the result of calcite dilution as indicated by a strong negative correlation between fe and calcium ca xrf data the mn fe ratio in the core from the maximum lake depth zh10 15 137 m revealed a moderate correlation with o 2 measurements in the lake bottom water confirming the successful application of the mn fe ratio to semi quantitatively reconstruct bottom water oxygenation in the lake mostly low ratios were observed between 1895 and the mid 1960s as a result of eutrophication however geochemical focusing and sedimentological factors can reduce the applicability of the mn fe ratio in reconstructing o 2 concentrations in the bottom water of lakes

indium mineralisation in a type granites in southeastern finland insights into mineralogy and partitioning between coexisting minerals abstract several promising exploration targets in the western parts of the wiborg batholith southeastern finland have been studied with respect to zn in ag as sn and cu ores occur both as massive in bearing magnetite sphalerite getmossmalmen as greisen style veins jungfrubergen and as cu dominant polymetallic quartz veins korsvik 1 and 2 sarvlaxviken area the cu dominant chalcopyrite bornite zn poor quartz veins are characterised by high in zn ratios 3000 roquesite cuins2 being a major indium carrier alongside sphalerite chalcopyrite and arsenopyrite in contrast sphalerite is the dominant in carrier in the greisen veins and massive ores characterised by lower in zn ratios

magnetic susceptibility applied as an age depth climate relative dating technique using sediments from scladina cave a late pleistocene cave site in belgium abstract here we demonstrate that magnetic susceptibility ms data from scladina cave belgium provide a time depth climate relationship that is correlated to the marine oxygen isotopic record and thus yields a high resolution relative dating method for sediments recovered from many archaeological sites this methodology will help resolve one of the major problems facing archaeologists namely the difficulty of acquiring absolute dates with reasonable precision for the period from 40 000 to 400 000 years or so the problem is that dating techniques applicable to most materials within this age range are subject to significant errors relative dating techniques such as magnetic secular variation or stable isotope methods offer the potential to improve this precision but both methods suffer from problems that make broad application to many sites impossible however for most archaeological cave sites ms measurements of cave sediments offers the potential for intra site correlation and paleoclimate estimation this is possible in protected cave environments because the ms of cave sediments results from climate processes active outside caves which cause variations in magnetic properties of the sediments that ultimately accumulate inside caves once deposited these materials are often preserved and their stratigraphy provides a time depth climate signal that can be identified therefore ms data can be used as an independent methodology alongside conventional methods such as sedimentology and palynology for relative age dates and correlation within and between sites by tracing evidence of paleoclimatic change this correlation has been used to infer an age of 90 000 7000 years for neanderthal skeletal remains recovered from scladina cave an important middle paleolithic archaeological site in belgium

lead isotope composition of caledonian sulfide bearing veins in sweden linear trend in the 207 pb 204 pb vs 206 pb 204 pb diagram extending from a normal caledonian lead composition 206 pb 204 pb nearly equal 17 9 to highly radiogenic values 206 pb 204 pb nearly equal 26 0 early proterozoic svecokarelian basement as source of the radiogenic component selective leaching of different minerals in the svecokarelian rocks and mixing with various proportions of nonradiogenic caledonian magmatic lead modified journal abstract

adaptations to sea level change and transitions to agriculture at khao toh chong rockshelter peninsular thailand this study reports on an analysis of human adaptations to sea level changes in the tropical monsoonal environment of peninsula thailand we excavated khao toh chong rockshelter in krabi and recorded archaeological deposits spanning the last 13 000 years a suite of geoarchaeological methods suggest largely uninterrupted deposition against a backdrop of geological data that show major changes in sea levels although there is a small assemblage of mostly undiagnostic ceramics and stone artefacts there are some distinct changes in stone artefact technology and ceramic fabric there is a substantial faunal assemblage with changes in both the mammalian and shellfish taxa during the pleistocene holocene transition that correlate with local sea level fluctuation this assemblage provides an opportunity to explore subsistence behaviours leading up to the transition to the neolithic we explore the implications for current debates on the prehistoric origins of agricultural subsistence in mainland southeast asia the data highlight the importance of local contingencies in understanding the mechanisms of change from foragers to agriculturalists

a high resolution late holocene landscape ecological history inferred from an intramontane basin in the western taurus mountains turkey abstract late holocene vegetation and geomorphological history is reconstructed from a 800 cm long high resolution palynological and sedimentological record sampled from bereket a 6 3 km 2 semi arid to sub humid intramontane basin in the western taurus mountains southwest turkey the well dated bereket record provides from cal 360 bc to cal ad 400 a unique record of biennial to decadal landscape changes caused primarily by intensive human impacts against a background of global climate variations during this period land clearance with multiple fire episodes intensive agricultural practices and grazing pressure profoundly altered the pre existing warm mixed forest increasing moisture availability since cal 280 bc has acted as a trigger to crop cultivation and mountain adapted arboriculture starting with juglans regia during the beysehir occupation phase pollen from olive groves have been recorded above 1400 m a s l only at cal 23 bc and have disappeared definitively at cal ad 294 during this phase the sediment accumulation rate was extremely high reflecting landscape instability from cal ad 450 to recent times the area has mainly recorded pasture and minor cultivation activities reflected in stable soils and thin colluvial depths

tides in a system of connected estuaries abstractthe spatial structure of tidal amplitude and phase in a simplified system of connected estuaries an idealized version of florida s intracoastal waterway is analyzed with a linear analytical model this model includes friction the earth s rotation and variable bathymetry it is driven at the connection with the ocean by a co oscillating tide model results compare well with observations of pressure and currents in a section of the intracoastal waterway on the east coast of florida the comparison suggests that the waterway is highly frictional causing the amplitude of the water elevation and tidal velocity to decrease away from the inlets to a minimum in the middle of the waterway the local phase relationship between velocity and water elevation changed nonlinearly from 90 with no friction to 45 with maximum friction in moderately to highly frictional basins the phase lag was consistently less than 45