dynamics of paleoenvironments in the cis ural steppes during the mid to late holocene the multi layered settlement of turganik in the tok river valley steppe region west of the urals has been studied using paleopedological and microbiomorphical methods early humans lived in the settlement during the eneolithic epoch the fifth millennium bc and in the early bronze age the fourth millennium bc the cultural layers attributable to the atlantic period of the holocene developed under conditions of a rather dry climate with the landscapes being dominated by the grass and herb steppe the settlement area was above the flood water level and was suitable for habitation the soils in its vicinity were kastanozems endosalic protosodic the final stages of the cultural layer formation bear traces of strong though short term floods with the deposits of the latter partly concealed traces of the preceding long term arid phase maximum aridity was during the final interval of the atlantic period the subboreal and subatlantic periods were noted for meadow chernozem soil formation luvic chernozems stagnic and an increasing proportion of arboreal species in the pollen assemblages some phytoliths of aquatic plants were found in the assemblages dominated by those of meadow grasses the climate was more humid and cool although short episodes of aridity were possible

pedogenic carbonate formation recrystallization versus migration process rates and periods assessed by 14c labeling 1 under arid to semihumid climatic conditions dissolution of primary carbonate and recrystallization with carbon c from soil co2 leads to accumulation of significant amounts of pedogenic secondary carbonate most soils of arid and semiarid regions contain a carbonate accumulation horizon the depth of which is related to climatic conditions and properties of parent material it remains unclear whether this carbonate migrates from the upper horizons before or after recrystallization with soil co2 the aim of this study was to determine recrystallization rates during initial pedogenesis and to estimate the accumulation depth of secondary carbonate based on c isotopic exchange during secondary carbonate formation in an experiment with alternating moisture conditions maize grown on 1 m high loess filled columns was pulse labeled in14co2 atmosphere every 3 weeks after 6 months portions of secondary recrystallized caco3 were determined in 5 cm segments based on 14c respired in the rhizosphere and subsequently incorporated into newly formed secondary carbonate more than 80 of recrystallized carbonate ca14co3 was leached from the uppermost 15 cm of the loess column and more than 70 of total secondary carbonate were accumulated in a depth between 15 and 50 cm based on the recrystallization rate calculated for the uppermost 15 cm of the loess column 1 77 0 26 10 5 day 1 between 300 and more than 1 700 years are necessary for complete decalcification of the upper 15 cm our modeled data are consistent with formation of calcic horizons under relatively humid conditions

changes in the magnitude frequency b value prior to large m 6 0 earthquakes in japan on the basis of akaike s bayesian information criterion abic a new method of estimating temporal and spatial variations in the magnitude frequency relation b value is developed the space time volume studied is divided into a number of segments having equal volumes for which b values are estimated the smoothness of the estimated b value is guaranteed by the introduction of a prior distribution the parameters of the prior distribution are chosen in such a way as to minimize the abic this method is employed to study the temporal and spatial variations of b values for microearthquake activity in the kanto tokai and tottori areas where seven earthquakes of m 6 0 have recently occurred the temporal variation of b values for the source region of the western nagano earthquake sep 1984 m 6 8 in the tokai area shows a decrease in b values about 2 years before the occurrence of the main shock similar findings before the southwestern ibaraki feb 1983 m 6 0 the southern ibaraki oct 1985 m 6 0 and the chiba dec 1987 m 6 7 earthquakes in the kanto area and the tottori earthquake oct 1984 m 6 2 in the tottori area were obtained these findings are confirmed by a precursor analysis pa in which effects of aftershocks are eliminated using a quantitative definition temporal variations of b values are classified into three groups increase decrease and no change the space time volume of decrease accounts for approximately 10 of the total volume for a period before the occurrence of earthquakes the decrease appears more frequently than might be expected from random chance the results suggest that the decrease in b values is a promising candidate to act as a precursory phenomena

the holocene paleoenvironmental history of central european russia reconstructed from pollen plant macrofossil and testate amoeba analyses of the klukva peatland tula region holocene climatic variability and human impact on vegetation are reconstructed from a region in central european russia which lies at an important ecotone between broadleaf forest and steppe for the first time in this region we adopt a multi proxy approach that combines analysis of local mire conditions from plant macrofossil and testate amoeba analyses with pollen based quantitative climate reconstruction the proxies indicate a long term warming trend from 9700 to 7500 cal yr bp interrupted by a series of short term cold events from 7500 to 5000 cal yr bp the results imply a relatively stable climate warmer and drier than present spanning the holocene thermal maximum since 5000 cal yr bp the data suggest a change to cooler climate but with centennial scale variability this shift at around 5000 cal yr bp is supported by extensive evidence from other sites in the early holocene the region was occupied mainly by pine and birch forests broad leafed forests of oak lime and elm expanded after 7800 cal yr bp and remained dominant until the last few centuries during the historical period vegetation changes have been driven mainly by human activities

magnetic geochemical and pedological characterisation of soil profiles from different environments and geological backgrounds near coimbra portugal abstract this study presents an application of environmental magnetism techniques for the characterisation of the soils near coimbra central portugal magnetic measurements scanning electron microscopy and geochemical studies were carried out on samples collected in 6 soil profiles in order to find possible relationships and to interpret environmental implications magnetic susceptibility saturation isothermal remanent magnetisation and isothermal remanent magnetisation at the backfield of 100 mt and 300 mt were measured hardirm sirm and s ratios were also calculated polluted soils showed higher values of magnetic parameters in the superficial soil horizons closer to the roads plants and urban areas the lowest values were observed in the deeper horizons of the soil and in the areas least disturbed by human activity the magnetic results also suggested that the magnetic signal of these soils is mainly influenced by ferrimagnetic magnetite like minerals and with only a minor contribution from antiferromagnetic carriers such as hematite minerals in unpolluted soils lithogenic contribution is reflected by the enhancement of magnetic susceptibility near parental rock material scanning electron microscope images of the topsoil samples revealed the presence of magnetic spherules typical of vehicular exhaust and combustion processes this evidence suggests that the atmospheric deposition of fly ash is the main reason for the enhancement of the magnetic signal in the topsoil chemical analyses showed that the concentration of various heavy metals was higher than the mean background values for portuguese soils and higher in superficial soils heavy metals showed significant positive correlation with magnetic properties the conclusions highlight the importance of using environmental magnetism methods and techniques in the evaluation process of soil evolution and pollution history throughout time

soils at archaeological monuments of the bronze age a key to the holocene landscape dynamics in the broadleaf forest area of the russian plain abstract during the second half of the holocene the russian plain experienced several climatic oscillations giving rise to changing vegetation patterns the spatial variability of vegetation changes and its effects on soils is still a matter of debate in the present study landscape response to holocene climatic cycles was analysed on the base of detailed morphological chemical and microbiomorphic analyses of a paleosol buried under the kurgan of the abashevo culture middle bronze age and a surface soil both soils located at the tokhmeyevo kurgan cemetery the middle volga region chuvash republic russia developed from the same parent material mantle loam at the same elevation and in close proximity to each other both soils classified as retisols show a similar morphology and key analytical features indicating similar environment the pollen and phytolith spectra confirm that both buried and surface soils formed under similar forest vegetation the buried and surface soils at the tokhmeyevo cemetery could be compared with the previously studied soils of the sareevo settlement of the early iron age and the taushkasy kurgan cemetery of the bronze age these studies confirm the stability of the forest environment at the southern boundary of the forest belt since the bronze age at the same time the buried soil at the tokhmeyevo cemetery has a thick mollic horizon and black organic coatings overlaying brown clay cutans in the argic horizons which sets it apart from the surface soil the radiocarbon dates for the humus in the mollic horizon and black coatings in the argic horizon are surprisingly close to each other about 5 5 cal ka bp and 5 2 cal ka bp respectively the data indicate that the black cutans are derived from degradation of the mollic horizon caused by a sudden increase in humidity during the episodes of extreme summer rainfall events our study also prove that the abashevo people had complicated burial funeral rites the earth mounds are made of the upper horizons of soils cut off from the surface in the vicinity the central part of the mound consists of soil bricks with albic material used for the interior while artificially rumpled material of the argic horizon was used for coverage the use of albic and artificially rumpled material of argic horizon for earth mound construction implies the similarity between the buried and surface soils since the bronze age until today thus the study of such construction techniques is important both for archaeology and paleogeography paleopedology

mineral magnetic properties of an alluvial paleosol sequence in the maya lowlands late pleistocene holocene paleoclimatic implications abstract in the maya lowlands region along the usumacinta river late pleistocene holocene profiles exhibit sedimentary characteristics and soil formation processes as a result of environmental conditions and human environmental interactions here we report a comprehensive environmental magnetic investigation on paleosols and sediments at the tierra blanca archaeological site which shows clear evidences of human occupation the pedogenetical magnetic properties were characterized by rock magnetism studies to determine the composition concentration and domain size distribution of magnetic minerals the late pleistocene paleosols were formed under the influence of a humid climate as shown by the presence of recent fine hematite formation directly related to reduction oxidation processes during gleysol development the transition from early to middle holocene was obtained from a paleovertisol dated as 2 34 2 3 ka which showed a marked heterogeneity in its magnetic parameters due to continuous argilloturbation processes the environmental conditions retrieved indicate the presence of a drought period around 5 5 ka the upper two paleosols were less developed and seems to be strongly affected by human activities during the maya classic period dated between 1 14 and 0 97 ka these soils were formed under more humid conditions and yielded a magnetic mineralogy hematite magnetite maghemite due to incipient weathering and anthropic disturbance

a new method in mineral magnetism for the separation of weak antiferromagnetic signal from a strong ferrimagnetic background 1 this paper describes a new magnetic method for determining the contribution of weakly magnetic hematite against a strongly magnetic e g magnetite background the method involves measurements of mfr a residual or final remanence after hysteretic demagnetization of saturated isothermal remanent magnetization in terms of sensitivity and precision our proposed method is superior to the currently popular approach known as the hirm method compared to the latter mfr has no error amplification caused by subtraction of terms the method utilizes the available software for hysteretic demagnetization function on an automated vibrating sample magnetometer vsm this in turn automatically decreases some of the disturbing effects of the strong magnetic background e g magnetic viscosity initially non zero offset of hirm for partially oxidized magnetite etc

pedological analysis as a key for reconstructing primary loess relief a case study from the magdalenian site in klementowice eastern poland abstract the subject of the study was a gentle and smooth loess slope featuring a magdalenian culture site located near the northern edge of the loess belt in eastern poland based on the probing of 130 soil profiles across a 10 10 m mesh within an area of 1 2 ha the land surface after the deposition of weichselian loess was reconstructed soil mapping indicated the patchwork character of the present soil cover which consists of luvisols of varying degrees of transformation resulting from agricultural use partly eroded and buried soils co occur in the upper part of the ridge flat non eroded soils in the middle part and eroded soils in the lower part in the archaeological site area with buried soils at the foot of the slope the thickness of the primary soil cover was reconstructed by means of geostatistical analyses this was used to reconstruct the primary undulating land relief characterised by numerous small convex forms small hillocks and hummocks and concave forms closed depressions and slope troughs these forms were levelled out by soil erosion in the course of agricultural use the planation of relief caused a decrease of the mean inclination by 25 and elevation difference by 13 the greatest changes occurred on the ridge flat where the denudation of small hillocks and the filling of closed depressions took place local inclinations decreased by up to fourfold and in some places the inversion of slope exposure occurred during the 210 years of agricultural use the eroded surfaces subsided by an average of 0 32 m and at most by 0 92 m which corresponds to an average of 1 5 mm and 4 3 mm per annum respectively less than 50 of the eroded soil material was deposited within the investigated slope most of the material was carried off beyond it the accumulated surface however is 2 5 times smaller than the eroded surface hence the accumulation indicators are slightly higher than the erosion indicators

pressure temperature time paths of regional metamorphism i heat transfer during the evolution of regions of thickened continental crust the development of regional metamorphism in areas of thickened continental crust is investigated in terms of the major controls on regional scale thermal regimes these are the total radiogenic heat supply within the thickened crust the supply of heat from the mantle the thermal conductivity of the medium and the length and time scales of erosion of the continental crust the orogenic episode is regarded as consisting of a relatively rapid phase of crustal thickening during which little temperature change occurs in individual rocks followed by a lengthier phase of erosion at the end of which the crust is at its original thickness the principal features of pressure temperature time ptt paths followed by rocks in this environment are a period of thermal relaxation during which the temperature rises towards the higher geotherm that would be supported by the thickened crust followed by a period of cooling as the rock approaches the cold land surface the temperature increase that occurs is governed by the degree of thickening of the crust its conductivity and the time that elapses before the rock is exhumed sufficiently to be affected by the proximity of the cold upper boundary for much of the parameter range considered the heating phase encompasses a considerable portion of the exhumation decompression part of the ptt path in addition to the detailed calculation of ptt paths we present an idealized model of the thickening and exhumation process which may be used to make simple calculations of the amount of heating to be expected during a given thickening and exhumation episode and of the depth at which a rock will start to cool on its ascent path an important feature of these ptt paths is that most of them lie within 50 c of the maximum temperature attained for one third or more of the total duration of their burial and uplift and for a geologically plausible range of erosion rates the rocks do not begin to cool until they have completed 20 to 40 per cent of the total uplift they experience considerable melting of the continental crust is a likely consequence of thickening of crust with an average continental geotherm a companion paper discusses these results in the context of attempts to use metamorphic petrology data to give information on tectonic processes 1984 oxford university press

the ustic isohumisol chernozem distributed over the chinese loess plateau modern soil or palaeosol abstract the ustic isohumisol chernozem widely distributed over the chinese loess plateau is classified as a modern soil by agricultural pedologists and as a palaeosol by geoscientists high resolution investigations into this soil including field observations element analysis optically simulated luminescence dating and measurements of magnetic susceptibility and particle size distribution were carried out over the plateau uplands the results show that the formation of physico chemical properties and development of the soil profiles has kept pace with the land surface growth because of incessant dust accumulation during the holocene the continuously intensified weathering of accumulated dust from 11 500 a b p had resulted in an increased chemical differentiation through time during the early holocene the development of the ustic isohumisol occurred over the uplands between 8500 and 3100 a b p when the chemical differentiation reached its maximum because of increased precipitation and ample soil moisture in response to the mid holocene climatic optimum the soil formation had sustained for ca 5400 years and ceased at 3100 a b p a major pedogenic regression occurred from 3100 a b p because of climatic aridity and intensified dust accumulation over the loess plateau the newly accumulated loess and topsoil has the ustic isohumisol buried at a depth of ca 50 80 cm in general the pedogenic regression has been intensified by incorporation of the reworked components by increased runoff and erosion redeposition large scale land reclamation extended to the uplands at ca 2170 a b p an agricultural landscape of dry farming has formed since ca 1500 a b p thereafter the present topsoil has accumulated and has been affected by the intensified cultivation and addition of barnyard manure in history the solubles are retained in the topsoil because of dry climate and scant soil moisture

pressure temperature and time indicators in mafic schist their application to reconstructing the polymetamorphic history of vermont mineral chemistry and overgrowth relationships in mafic schist from vermont are shown to be sensitive indicators of pressure temperature and relative time and to be good chronicles of the paleozoic history of this polymetamorphic terrane within the common assemblage amphibole chlorite epidote plagioclase quartz ti phase carbonate k mica fe 3 oxide electron microprobe analyses show that increasing metamorphic grade as defined by intercalated pelitic schist is recorded by an increase in the edenite glaucophane and tschermakite contents of amphibole in the anorthite content of plagioclase and in the substitution of al vi f 2 ti al iv for fe 2 mg mn si in biotite chlorite and muscovite with increasing pressure the glaucophane component of amphibole increases for medium pressure metamorphism the albite oligoclase gap is in the garnet zone where amphibole has between 1 2 and 1 8 formula proportion al iv and al vi fe 3 ti cr this gap is below the garnet isograd in low pressure mafic schist where al iv and al vi fe 3 ti cr in the amphibole are both less than 0 6 mineral growth periods observed are characterized by metamorphic grade and facies series and are assigned to two ordovician taconic and two devonian acadian events silurian devonian mafic schist in northeastern vermont records two periods of low pressure devonian metamorphism these events are expressed by medium pressure and low pressure metamorphism in the cambrian and ordovician rocks to the west and south in the pre silurian rocks high pressure and medium pressure metamorphism is assigned to the ordovician the observed high pressure metamorphism is confined to a 110 by 40 km area along the green mountain anticlinorium axis in north central vermont

quantitative extraction and analysis of carriers of magnetization in sediments we have applied an integrated procedure for quantitative magnetic mineral extraction based on the separation method of petersen von dobeneck vali 1986 to a range of sediment types to examine the efficiency and representative nature of the extraction process carriers of magnetization have been identified by rock magnetic measurements microscopy and x ray diffraction quantification of the extraction efficiencies is achieved by before and after extraction rock magnetic measurements susceptibility anhysteretic and isothermal remanences these magnetic measurements show that our modified extraction method extracts large proportions of the magnetization carriers in a range of sediment types e g over 75 per cent for magnetite dominated sediments the extraction efficiency is dependent on the sample magnetic mineralogy and whether the magnetic grains occur as discrete grains or as inclusions within host grains susceptibility extraction efficiencies are strongly dependent on whether the susceptibility is of paramagnetic or ferrimagnetic origin the amount of material recovered in the extract shows some inverse correlation with the density of the sediment suspension used during extraction in terms of the mineralogies extracted we identify a diverse and complex range of mineral assemblages all sizes of discrete grains of magnetite are extracted including single domain and superparamagnetic grains and chains of bacterial magnetite other commonly extracted iron and titanium oxides are haematite and ilmenite ferrimagnetic chromites and sulphides were also obtained from some samples considerable amounts of quartz and feldspar are extracted due to the presence of magnetic inclusions within these diamagnetic host grains in the deep sea sediments we examined feldspars constitute a large proportion of the extracts but are significantly less abundant in other sediments where quartz is dominant a wide variety of paramagnetic minerals was identified in the extracts including pyroxenes amphiboles chlorites micas mg cr spinels garnets ti oxides apatites tourmaline and zircon many of which contain ferrimagnetic inclusions possibly less than 0 1 m in grain size dissolution of ultrafine grains of magnetite during pre extraction carbonate dissolution as suggested by sun jackson 1994 does not occur in our samples

surface paleosols of the loess island within moscow glacial limits vladimir opolie abstract vladimir opolie is a typical loess island with soil pattern that differs strikingly from that of adjacent territories soils are characterized by a controversial set of features they have common features with other loess islands located in various environmental zones similar dependence on microtopography with second humus horizons in soils within depressions and accumulation of carbonates in soils on the main surfaces on the other hand they differ from soils of loess islands formed on typical loess due to specific features of sediments mantle loams and a northern variety of loess a pedostratigraphic approach to the study of soils of vladimir opolye reveals that constitution of the upper loess strata depends on paleocryogenic microtopography and that relict soil features second humus horizon pattern of carbonates distribution are syngenetic with the final stages of loess sedimentation the abundance of relict features indicates that the soils of vladimir opolie are surface paleosols

new aspects of natural science studies of archaeological burial monuments kurgans in the southern russian steppes abstract soil archeological soil studies on the kurgan burial site peregruznoe located to the north of the yergeninskaya upland 80 km from the city of volgograd russia were performed for the first time data on the structure of soil cover in the dry steppe zone during sarmatian times ad 1 were obtained from paleosol data it was established that in the second half of the first century ad the prevailing humid climate progressively changed to more arid conditions similar to those of the modern time using the methodology and theoretical conceptions of archaeological soil science the age of the monuments investigated was detailed for one of the kurgans the original technology involved in erecting the monument was reconstructed and the time of year when construction had taken place was determined principally new information on the details of the funeral rites of the middle sarmatian tribes in the lower volga region was obtained

classification seasonality and persistence of low frequency atmospheric circulation patterns abstract orthogonally rotated principle component analysis rpca of northern hemisphere 1 month mean 700 mb heights is used to identify and describe the seasonality and persistence of the major modes of interannual variability the analysis is detailed and comprehensive in that 1 a high resolution approximately equal area 358 point grid is used for the virtually maximum possible 35 year period of record 2 a positive bias in the nmc data base in the early 1950s in the subtropics is largely eliminated for the first time and 3 homogeneous separate analyses of each month of the year are carried out detailing the mouth to month changes in the dominant circulation patterns winter results are similar to those of other recent rpca and teleconnection studies except that some less obvious patterns are identified and further detail of the better known patterns is provided two north south dipole patterns are found over the pacific ocean west pacific oscillation and east pacific pattern and over the atla

fossil bacterial magnetite in deep sea sediments from the south atlantic ocean the magnetostratigraphy of deep sea sediment cores has proven to be a powerful and high resolution method of dating and comparing sedimentary records in contrast to this widespread application relatively few attempts have been made to analyse and identify the mineralogy grain size and origin of the carrier of the remanent magnetization1 2 it is widely assumed that dominant ferrimagnetic minerals in deep sea sediments are of lithogenic origin that is that they derive from oceanic or continental detritus volcanic ashfalls micrometeorites hydrothermal precipitation or chemical mineralization processes a very different view was taken by kirschvink and lowenstam3 who suggested that fossil remnants of magnetite mineralizing organisms in particular magnetotactic bacteria might play an important part in the magnetization of sediments deposited in certain detritus poor aquatic systems we have used rock magnetic diagnostic methods to characterize the magnetic phases in deep sea sediments from the south atlantic these phases were then extracted and studied with the electron microscope our results indicate that fossil bacterial magnetite is the main carrier of the natural remanent magnetization in sediments ranging in age from quarternary to eocene different types of bacterial magnetosomes were detected most of them occurring in chains of identical particles and nearly all of them falling into the theoretically determined4 size range of single domain magnetitite

correlation of early and mid holocene events using magnetic susceptibility in estuarine cores from bays along the northwestern gulf of mexico abstract magnetic susceptibility ms of sediment and rock has been suggested as a tool to indicate changes in weathering patterns source area trace metals and particle size each of which may also provide a paleoclimate record we test the utility of ms in recording previously documented climate changes within holocene estuarine deposits from four bays along the texas coast of the northwest gulf of mexico baffin copano corpus christi and galveston bays ms analysis indicates three populations of anomalously high values at or near the 8 2 ka climatic event during the mid holocene at 5 5 5 0 ka and at 3 6 ka ms measurements from copano and corpus christi bay cores suggest that the 8 2 ka event may have been multiple events although the initial focus of this study was on the use of ms to record the 8 2 ka event the younger ms anomalies that correlate within the mid holocene are equally important and more pronounced for the use of ms as a paleoclimate proxy the strong correlation of anomalies between 5 5 5 0 ka within multiple cores suggests a regional response to environmental changes that affect the abundance of magnetic minerals in the bays we use multiple analyses to attempt to determine the cause of the observed ms anomalies in the bays frequency dependent ms indicates that the majority of measured samples including the anomalies have no biogenically produced ultrafine magnetite with the exception of anomalies at 8 5 ka 8 3 ka and 7 8 ka in copano bay particle size of the sediment is compared with ms measurements from baffin and copano bays suggesting a weak correlation between particle size and ms inductively coupled plasma spectrometry and x ray fluorescence fail to indicate anomalous values correlating with the observed ms anomalies both methods probably lack the resolution to detect the minor differences needed to cause the observed changes in ms x ray diffraction analysis indicates the possibility of a minor increase in magnetite at an ms anomaly in the corpus christi bay record which may be sufficient in causing the elevated ms we present three explanations of climate controlled ms for the anomalous intervals 1 accelerated sea level rise decreased the orbital depth of waves on the bottom of the bays as a result the sedimentation rate increased due to a higher accommodation for deposition due to rapid deposition the flooding surface preserved authigenic ferromagnetic minerals within a redox layer which deterred the cycle of fe from one phase to another 2 an influx of detrital magnetite maghemite to the bays occurred due to flash flooding during arid periods 3 the ms anomalies observed in the cores represent an increase in background magnetic material models 1 2 and 3 apply to the anomalies near 8 2 ka and only models 2 and 3 provide plausible explanations for the younger anomalies as there is no documentation of sea level rise during those periods despite the uncertainties in the mechanisms behind the ms anomalies the correlation of the climatic events within multiple bays along the texas coast suggests that ms may provide a correlation tool within estuarine fills of the gulf of mexico basin and perhaps across the globe

transformation of cumulate mafic rocks to granulite and re equilibration in amphibolite and greenschist facies in ne sardinia italy abstract the ultramafic amphibolites hosted in the hercynian migmatite of ne sardinia consist of three main compositional layers a b c from a few metres to a few decametres thick layer a is made up of coarse grained olivine chlorite amphibole spinel minor pyroxene garnet and rarely plagioclase layer b is made up of coarse grained plagioclase olivine pyroxene spinel garnet and amphibole layer c consists mainly of porphyroblastic garnet pyroxene large amphibole grains up to 5 cm and minor plagioclase on the basis of mineral assemblages and microstructures three stages of mineralogical re equilibration can be recognised granulite amphibolite and greenschist primary igneous olivine and anorthite reacted under granulite conditions to produce coronas consisting of orthopyroxene clinopyroxene green spinel and garnet the amphibolite stage is characterised by the formation of brown and green clinoamphiboles between pyroxene and corona garnet anthophyllite talc mg rich chlorite plagioclase and cr bearing spinel greenschist stage minerals mostly replacing the mafic minerals consist of tremolite fayalite epidote albite calcite dolomite and serpentine the history of the ultramafic amphibolites started with igneous crystallisation and continued through granulite t 700 740 c p 8 10 kbar amphibolite t 580 640 c p 4 6 kbar and greenschist facies t 330 400 c p evaluation of p t conditions indicated a p t path from the protolith to granulite stage characterised by an increase in pressure and temperature and then from the granulite facies through amphibolite to the greenschist stage characterised by a decrease in pressure and temperature the petrological evolution of the ultramafic amphibolites and the p t time path is discussed in the context of the hercynian orogeny in sardinia

holocene development of soils in response to environmental changes the novosvobodnaya archaeological site north caucasus abstract soil archaeological studies in north caucasus indicate that the expansion of broad leaved deciduous forests from mountains to foothills and piedmont plain took place about 3000 years ago after the middle holocene steppe stage at this time steppe chernozems transformed into luvisols under forests often the luvisol profiles preserve the relict humus horizon and paleokrotovinas mole tunnels inherited from the chernozemic stage within the same period normally developed soils evolved on the surface of burial mounds luvisols on mounds composed of loess and chernozemic material and rendzinas and luvisols with a calcareous horizon on loamy mounds with a limestone paving stone armour used to strengthen the mounds the rates of profile differentiation and some pedogenic processes have been calculated in the eluvial horizons of luvisols developed on loess or charnozemic material the rate of clay loss was up to 7 8 g m 2 year

magnetic mineralogy of soils across the russian steppe climatic dependence of pedogenic magnetite formation formation of ferrimagnets in well drained buffered unpolluted soils appears to be related to climate and especially rainfall if robust this magnetism rainfall couple can be used to estimate past rainfall from buried soils particularly the multiple soils of the quaternary loess soil sequences of central asia however dispute exists regarding the role of climate vs dust flux for the magnetic properties of modern loessic soils here we examine the mineralogical basis of the magnetism rainfall link for a climate transect across the loess mantled russian steppe where critically dust accumulation is minimal at the present day magnetic and independent mineralogical analyses identify in situ formation of ferrimagnets in these grassland soils increased ferrimagnetic concentrations are associated with higher annual rainfall xrd and electron microscopy show the soil formed ferrimagnets are ultrafine grained 50 nm and pure ferrimagnetic contributions to ma ssbauer spectra range from 17 in the parent loess to 42 for a subsoil sample from the highest rainfall area total iron content varies little but the systematic magnetic increases are accompanied by decreased fe2 content reflecting increased silicate weathering for this region parent materials are loessial deposits topography is rolling to flat and duration of soil formation effectively constant the variations in soil magnetic properties thus predominantly reflect climate and its co variant organic activity statistical analysis identifies strongest relationships between rainfall and magnetic susceptibility and anhysteretic remanence this magnetic response correlates with that of the modern soils across the chinese loess plateau such correlation suggests that the rainfall component of the climate system not dust flux is a key influence on soil magnetic properties in both these regions

investigation of vegetation history of buried chernozem soils using near infrared spectroscopy nirs abstract the environmental conditions of the evolution of chernozems in central europe have not been satisfactory explained in this paper seven buried chernozems were investigated using near infrared spectroscopy nirs in order to get information about the former vegetation cover near infrared nir data were collected from organic matter of recent natural grasslands and forests the spectra from these two groups of soils were perfectly discriminated by a multivariate statistical analysis the statistical model was applied on the buried soils there are four types of vegetation development within the chernozems before the burial comparison to other paleoenvironmental proxies shows no major contradiction and confirms the potential of the nirs as a paleopedological proxy the identified changes of vegetation are from grassland vegetation to forest vegetation and vice versa these changes bring new data to the discussion about the pedogenesis of chernozems according to the radiocarbon dating buried soils developed and were preserved not only in the preboreal and the boreal but also in later phases of the holocene

growth rates of pedogenic carbonate coatings on coarse clasts abstract growth rates of pedogenic carbonate coatings on clasts can be used as a simple quantitative index of soil and sediment age as well as a chronological framework for palaeoecological reconstructions they are also probably connected with general intensity of formation of bk horizons in soils previously data on coating growth rates were restricted ecologically and geographically to desert regions of north america this paper presents growth rates of holocene pedogenic carbonate coatings on clasts within an extended range of environments calculated on the basis of archaeological and radiocarbon dating the rates in this study are higher than in earlier reports carbonate coatings can thicken with rates up to 1 mm 1000 years or higher in semi arid and semi humid climates at least five factors are likely to control growth rates 1 climate 2 lithology of carbonate parent material 3 depth under the soil surface 4 clast size 5 bulk density and composition of cutans favorable factors for comparatively rapid coating thickening seems to be climatic conditions ranging from semi arid to semi humid high carbonate content of parent material and large size of clasts there is also an optimal depth of carbonate coating growth in a soil profile little information on bulk density and composition of cutans is available but they appear to play an important role as one of the factors governing growth rates of pedogenic carbonate coatings on clasts

paleosols from the groups of burial mounds provide paleoclimatic records of centennial to intercentennial time scale a case study from the early alan cemeteries in the northern caucasus russia abstract buried soil chronosequences under a series of early alan kurgans burial mounds in the vladikavkazkaya depression of the northern caucasus russia were studied to derive a high resolution paleoclimatic record from the variations of the selected paleosol properties haplic chernozems occur under kurgans and on the actual land surface three kurgan cemeteries brut 1 brut 2 and beslan dated from the end of the second to the beginning of the seventh centuries ad have been studied the cemeteries are situated close to each other under similar lithological and geomorphological conditions but differed in the paleosols preservation the brut 2 site has been recently altered due to annual ploughing and intensive irrigation for more than 30 years the background soils and paleosols of the brut 2 site have been compared with synchronous soils of non irrigated brut 1 and beslan sites to detect pedogenic properties that are less changed by irrigation and thus comprise the soil memory stronger black color of humus horizon increase of humus content and decrease of humus 13c values clear signs of biological activity absence of morphological and analytical signs of solonetz properties diffused carbonate white soft spots in the bca horizon and decreasing carbonate content are thought to be related to the comparatively humid climatic conditions in the region on the contrary relatively low humus content tongue like lower boundary of humus horizon increase of humus 13c values morphological signs of solonetz properties together with high content of exchangeable na relatively large and clearly shaped carbonate white soft spots in the paleosols of the brut 2 site as well as increase of density thickness of the carbonate pseudomicellium and high carbonate content in the upper part of profiles in the paleosols of the non irrigated brut 1 site are assumed to be xeromorphic features indicating comparatively drier climatic conditions the paleosols of the earliest chronointerval of burial the end of the second to the beginning of the third centuries ad demonstrate clear xeromorphic properties which indicate a relatively dry climate with a mean annual precipitation 50 100 mm less than today the estimated duration of the period with such climatic conditions is thought to be not less than 100 years in addition those paleosols have some weak signs of humid conditions indicating that between the end of the first and the middle of the second centuries ad the climate was getting more moist mean annual precipitation became equal or slightly higher than today the paleosols buried in the first half of the fifth century ad again demonstrate the gradual enhancement of xeromorphic properties reflecting the next stage of droughts thus the period with favourable humid climate when the early alan culture flourished in the northern caucasus was relatively short about 400 years studying the detailed chronosequence in the non irrigated brut 1 site the records of intercentennial time scale soil properties variability produced by comparatively fast pedogenic processes typical for the steppe zone i e humus formation and accumulation bioturbation carbonate accumulation and transformation and solonetzization have been provided

environmental trends during the bronze age recorded in paleosols buried under a big kurgan in the steppes of the ponto caspian area abstract the southern steppes of european russia are rich in archaeological monuments that were extensively studied for many decades nevertheless paleosols buried under the burial mounds and especially the big kurgans of the bronze age in the ponto caspian area did not receive proper attention the paper focuses on soil evolution and climate dynamics during the bronze age based on the study of soils buried during several stages of earthen mound construction within one big kurgan in the kuban azov plain russia the kurgan 1 in the beysuzhek 9 kurgan cemetery of the bronze age situated in the korenovsky district krasnodar region consists of three earthen mounds made at different times the soils buried under three mounds of the kurgan are located in close vicinity from each other and have similar lithology and geomorphic position they form a chronosequence representing three time slices moreover the chronosequence displays a certain chronological order of burial paleosols were first buried in the center of the kurgan and later closer to its periphery the height of the kurgan is about 4 m that ensures good preservation of the buried soils the research is based on the comparative analysis of morphology micromorphology and analytical properties of three paleosols buried under different constructions in the kurgan and surface soil also the palynological analysis was performed for the uppermost layers 0 5 cm of three paleosols during the first stage of the kurgan construction the novotitorovo archaeological culture of the early bronze age at the 27th 22nd centuries bc the climate of the region was sufficiently humid and provided a high bioproductivity for surrounding landscapes the interval between the second and third stages of kurgan construction was marked by the gradual increase in aridity during the third stage of the kurgan construction the catacomb archaeological culture the middle bronze age the 21st 16th centuries bc the climate was mostly arid the results of the palynological analysis are in agreement with the study of paleosols during the construction of the kurgan the vegetation pattern corresponded to a southern forest steppe the percentage of herbaceous plants increased markedly and steppe species appeared during the time of catacomb culture

metamorphic amphiboles composition and coexistence amphiboles have long been key players in metamorphic petrology the concept of facies was developed for rocks of basaltic composition eskola 1920 1939 fyfe et al 1958 and within this concept amphiboles had a leading role the first appearance of amphiboles the presence of amphiboles of certain compositions or last appearance of amphiboles that are replaced by pyroxene bearing assemblages mark a number of major facies boundaries the transition from greenschist to amphibolite facies is marked in part by hornblende replacing actinolite and the granulite facies is defined by the breakdown of hornblende to orthopyroxene bearing assemblages the blueschist facies is defined by the appearance of glaucophane while the transition from blueschist facies to eclogite facies conditions is indicated by the breakdown of glaucophane to omphacitic pyroxene bearing assemblages references to amphibole names actinolite glaucophane or rocks characterized by certain amphiboles amphibolite hornblende figure prominently in six facies names turner 1981 liou et al 1985 oh et al 1988 evans 1990 peacock 1993 a large part of the literature that is devoted to metamorphic petrology of amphiboles concerns reactions which produce amphiboles from more hydrated mafic igneous rocks or lead to the destruction of amphiboles as they break down to form anhydrous or nearly anhydrous mineral assemblages consequently amphiboles can be thought of as occupying the wide intermediate portion of p t xfluid space in which metamorphic rocks are found the number of citations of the published amphibole nomenclature serves as a yardstick meterstick of the interest in amphiboles and a minimum estimate of the amount of literature devoted to this mineral two versions of the nomenclature of amphiboles have appeared 1978 and 1997 leake 1978 leake et al 1997 and they have been cited a over 2300 times in the past 28 years this works out to a minimum

environmental magnetism a practical guide j walden f oldfield j and smith eds technical guide no 6 quaternary research association london 1999 243 pp price 17 00 9 00 to qra members isbn 0 907780 42 3

paleosols in late moscovian carboniferous marine carbonates of the east european craton revealing great calcimagnesian plain paleolandscapes abstract late paleozoic strata commonly include lithologic cycles cyclothems driven by sea level fluctuations that repeatedly flooded and exposed broad expanses of epeiric shelves such successions commonly with multiple unconformities are well documented in permo pennsylvanian sedimentary successions but remain less understood in the east european craton eec part of the euramerican continental shelf rim this study documents unconformities and paleosols from the podolskian to myachkovian middle pennsylvanian epeiric carbonate succession of the eec and explores the non actualistic soil types landscapes and the character and density of vegetation in this pennsylvanian calcimagnesian dryland environment thin mostly 1 m paleosols developed at seven successive unconformities consist of an upper terrestrial clay layer or topclay a crust of beta calcrete beneath the topclay and a weakly karsted substrate limestone with rare rhizocretions solution pits and small 3 m deep karst sinkholes are rare nontruncated topclays commonly consist of two layers in situ clayey epipedons and resedimented terrestrial clays the latter are interpreted as playa sediments the myachkovian unconformities of the northernmost localities studied near arkhangelsk lack beta calcrete and root traces and the limestone beneath these unconformities is sepiolitized in podolskian paleosols of the southern moscow basin the topclays are predominantly palygorskitic the myachkovian paleosol clays are smectitic illitic with occasional chlorite admixture the majority of late moscovian paleosols surveyed formally conform to lithic rendollic haplocalcids within the aridisol class or rendzic calcic leptosols a detailed study of a representative podolskian paleo pedon reveals development of shallow soil carbonate low alumina bases and ba sr ratios enhanced mn and sr presence of soil gypsum and opal and a characteristic peak in magnetic susceptibility all suggesting a semiarid to arid pedogenic environment the palygorskite clay of this paleo pedon retains 1 1 1 5 of connate organic matter in the form of covalently bound organomineral complexes and is fulvate dominated resembling organic matter from extant dryland soils the palygorskitic composition of podolskian topclays and shallow 30 cm pedogenic carbonates is interpreted to reflect hot well drained semidesert conditions with precipitation less than 300 mm yr the transition from palygorskitic to smectitic soil clays across the podolskian myachkovian boundary apparently deeper soil carbonate and an increase in the degree of karstification record a general increase in humidity such that annual precipitation may have exceeded 300 400 mm the available data reconstruct the great calcimagnesian plain landscapes formed during low sea level supposedly glacial phases across tens of thousands of square kilometers of the eec this non actualistic system apparently lacked a fluvial network and was covered by uniform soils and playas the primary productivity of this early 310 305 ma old dryland ecosystem inferred from high toc and rhizogenic beta calcretes was not markedly different from present day steppe or savanna grasslands and semideserts in the northernmost outcrops surveyed near arkhangelsk drier conditions probably limited colonization by higher plants the available data open a hidden chapter in the paleozoic evolution of terrestrial ecosystems which is not recorded by paleobotany and urges modifications in the concept of low productivity character of pre miocene dry landscapes

the environment of the early iron age at the southern fringe of the forest zone of the russian plain abstract landscape response to the late holocene climatic cycles was studied on the base of detailed morphological analytical and micro biomorphic research of a soil buried under fortification earth wall of the early iron age around 2000 yr b p and a surface soil both soils formed on similar surfaces with the same lithology mantle loam underlain by calcareous loess at the same elevation and in close proximity to each other the buried soil has a complete profile that was influenced by human activity prior to the burial and subjected to diagenesis after the burial in addition both soils retisols show similar morphology and key analytical features indicating close similarity of the landscapes in the study area that existed in the early iron age and those that are present nowadays micro biomorphic assemblages phytoliths pollen microbial genes support this conclusion landscape stability at the southern fringe of the forest zone makes it possible to establish the northern limit of the wide belt which stretches out from dry steppe to northern forest steppe where landscape shifts influenced by the late holocene climatic cycles occurred the features of the diagnostic horizons of the studied retisols are indicators of stability in the studied time space range the study of microbial genes which was performed in the studied soils for the first time showed that both content and taxonomic structure of soil microbial communities are promising paleoclimatic proxies as well as a record of diagenetic changes in buried soils

pedogenic carbonate cutans on clasts in soils as a record of history of grassland ecosystems pedogenic carbonate cutans coatings pendants rinds on coarse clasts are common in stony soils of arid and semiarid regions dominated by open vegetation this paper gives an overview of the potential of the carbonate cutans for paleograssland research using data from literature and personal observations carbonate coatings are stratified into distinct microlamina which can provide a record of local environmental changes lamina made of a rather pure calcium carbonate with better formed and parallel oriented crystals seem to be indicative of relatively dry phases that were less favorable for biological activity a high content of admixtures poorer formed and randomly oriented calcite crystals presumably mark wetter periods characterized by climatic amelioration at a most general level n 13 c of the cutan carbonate can provide information on the type of photosynthesis of local vegetation whereas n 18 o in carbonate material of the coatings correlates with oxygen isotopic composition of precipitation water at the site and is sensitive to fluctuations in temperature to obtain chronological evidence on cutan formation the 14 c and th u methods can be applied with certain limitations additionally cutan growth rates can be used to evaluate the age of these features fl 2002 elsevier science b v all rights reserved

austrian mis 3 2 loess palaeosol records key sites along a west east transect based on a w e transect through the northern loess regions of austria palaeoenvironmental studies were carried out in three loess palaeosol sequences gunderding krems wachtberg and stillfried b locus typicus to complement available results in the context of a multi methodological approach on the base of previously published datings our study concentrates on the mis 3 2 transition the results of detailed micromorphological investigations prove that palaeopedogenesis frost processes and sedimentation rates differ in their spatial occurrence in the loess belt of austria all three sequences are in line with the general trend of a reduced intensity of pedogenic and cryogenic features from western to south eastern europe which can be explained by lower atlantic moisture influence towards the east interstadial cambic horizons are well developed in the mis 3 sequence of western austria whereas the eastern loess profiles only show weak pedogenesis in all studied sequences frost processes were active during the upper mis 3 and mis 2 the studied mis 2 records are characterised by tundra soils with reductaquic horizons which is a clear sign for prolonged phases of permafrost on the spatial scale the sedimentation rate increases in the eastern loess regions and particularly the krems wachtberg sequence in the centre of the transect experienced an exceptionally high sedimentation rate and can thus be seen as one of the most important high resolution records for the mis 3 2 transition in european loess regions

garnet orthopyroxene plagioclase quartz barometry refinement and application to the english river subprovince and the minnesota river valley recent experimental theoretical and thermodynamic studies permit better calibration of two reactions for geobarometry grossular pyrope quartz anorthite enstatite grossular almandine quartz anorthite ferrosilite if both reactions are applied using the same thermodynamic data and activity models they should yield the same pressure for a given garnet pyroxene plagioclase quartz assemblage application to a variety of high grade terrains generally yielded excellent results however poor results have been obtained for high fe rocks which can be traced to errors in activity models for garnet and or pyroxene either a two site ideal mixing model for orthopyroxene cf wood and banno 1973 underestimates enstatite activity for high fe orthopyroxenes or the ganguly and saxena 1984 model overestimates pyrope activity in low mg garnets

variation of soil magnetism across the russian steppe its significance for use of soil magnetism as a palaeorainfall proxy abstract modern soils across the chinese loess plateau exhibit strong but disputed correlation between their pedogenic magnetic content and annual rainfall a soil magnetism rainfall transfer function could provide a quantitative proxy of quaternary rainfall for this region however some argue that magnetic dilution through spatially varying fluxes of weakly magnetic dust controls the soil magnetic properties here we test the soil magnetism rainfall couple by examining 22 russian steppe soils free of present dust accumulation across a climatic transect from the semi arid caspian region to the more humid caucasus the soils display systematic increases in topsoil ferrimagnetic concentrations with the exception of climate and its co variant vegetation soil forming factors are essentially constant across this stable area hence the soil magnetic variations dominantly reflect climate and from statistical analysis principally rainfall further the russian steppe magnetic rainfall relationship matches that observed for the chinese loess plateau these independent data thus substantiate the soil magnetism rainfall climofunction and by inference eliminate dust dilution as a significant magnetic factor

records of climatic changes in the carbonate profiles of russian chernozems abstract the carbonate profiles of chernozems bear important information on soil processes and can be successfully used for paleoenvironmental reconstruction in the northern caucasus region russia carbonate profiles of chernozems were compared under anthropogenic irrigation and natural changes of moisture regime the results for irrigation served as the basis for understanding the response to natural climatic changes a soil chronosequence consisting of soils buried under archaeological mounds dated to 5000 3800 4000 and 1600 1700 bp and modern surface soils was studied in a similar way the soils buried 5000 and 3800 4000 bp had distinctive migrational and segregational carbonate accumulations cas the migrational forms occurred in the surface horizons and contained 89 92 calcite with the highest dissociation temperatures in the soils buried 1600 1700 bp the carbonate profile was clearly defined in terms of migrational cas they occurred only in the deeper horizons had no clear boundaries and were diffused throughout the soil mass in the modern surface soils the migrational cas have almost disappeared and the segregational cas have the largest halos of recrystallised carbonates the values of 13c for cas in the soils buried 5000 and 3800 4000 bp were lighter than in the soils buried 1600 1700 bp and the modern surface soils 10 6 to 9 9 and 9 6 to 8 8 respectively we conclude that the climate of the region during the second half of the holocene changed from relatively dry and warm in the atlantic period 5000 bp to more humid and cooler in the early subboreal 5000 4000 bp since 4000 bp the climatic conditions have remained relatively stable with some changes in moisture regime resulting from human activities in recent centuries

magnetic petrology of variably retrogressed eclogites and amphibolites a case study from the hercynian basement of northern sardinia italy 1 this study constitutes the first attempt to integrate rock magnetism and metamorphic petrology in the hercynian basement of northern sardinia the investigation focused on the magnetic petrology of variably retrogressed eclogites and amphibolites from two suites of basic meta igneous rocks which occur along a major tectonic line posada asinara line within a medium grade mg and a high grade hg metamorphic complex consistent with petromagnetic results hg metabasites contain variable amounts of monoclinic pyrrhotite intergrown with rutile and titanomagnetite occurring as inclusions in garnet abundant ilmenite associated to secondary hornblende and with sphene low ti magnetite rims and rutile both as inclusions in ilmenite and as discrete grains in mg metabasites pyrrhotite is restricted to amphibolites of the posada valley area where it occurs as rare inclusions in garnet all samples are characterized by variable amounts of ilmenite rutile and sphene which show the same microstructural features described in hg rocks microstructural evidence and geothermobarometric data indicate that 1 pyrrhotite and titanomagnetite likely formed prior to and remained stable during the eclogite facies metamorphic peak and 2 the growth of ilmenite and sphene can be attributed to the amphibolite facies retrogression mainly due to model reactions such as garnet omphacite rutile h2o hornblende plagioclase ilmenite and amphibole ilmenite o2 sphene magnetite quartz h2o the results from our combined petrological and petromagnetic study corroborate the hypothesis that significant volumes of mafic ultramafic rocks similar to some of the investigated outcrops may account for the magnetic anomalies flanking the northeastern part of the posada asinara line

time dependence of magnetic susceptibility of soil chronosequences on the california coast abstract as the age of the soils in a chronosequence on the california coast increases the difference between the magnetic susceptibility of eluvial and illuvial horizons increases and the residual susceptibility after extraction with citrate bicarbonate dithionite cbd decreases enhanced susceptibility results from the conversion of nonferrimagnetic minerals to secondary ferrimagnetic forms most likely maghemite and the preferential accumulation of inherited and pedogenic magnetic minerals little enhancement occurs for pedons younger than 40 000 yr by 124 000 yr most of the magnetic susceptibility can be attributed to forms soluble in cbd magnetic susceptibility appears to vary systematically over time for three chronosequences from areas with mean annual precipitation ranging from 650 to 1500 mm yr 1 magnetic susceptibility enhancement may be a useful parameter for estimating soil age in certain climates

assessment of quantitative aftershock productivity potential in mining induced seismicity strong mining induced earthquakes exhibit various aftershock patterns the aftershock productivity is governed by the geomechanical properties of rock in the seismogenic zone mining induced stress and coseismic stress changes related to the main shock s magnitude source geometry and focal mechanism in order to assess the quantitative aftershock productivity potential in the mining environment we apply a forecast model based on natural seismicity properties namely constant tectonic loading and the gutenberg richter frequency magnitude distribution although previous studies proved that mining induced seismicity does not obey the simple power law here we apply it as an approximation of seismicity distribution to resolve the number of aftershocks not considering their magnitudes the model used forecasts the aftershock productivity based on the background seismicity level estimated from an average seismic moment released per earthquake and static stress changes caused by a main shock thus it accounts only for aftershocks directly triggered by coseismic process in this study we use data from three different mines mponeng south africa rudna and bobrek poland representing different geology exploitation methods and aftershock patterns each studied case is treated with individual parameterization adjusted to the data specifics we propose the modification of the original model i e including the non uniformity of m0 resulting from spatial correlation of mining induced seismicity with exploitation the results show that even when simplified seismicity distribution parameters are applied the modified model predicts the number of aftershocks for each analyzed case well and accounts for variations between these values such results are thus another example showing that coseismic processes of mining induced seismicity reflect features of natural seismicity and that similar models can be applied to study the aftershock rate in both the natural and the mining environment

the genesis and age of the argillic horizon in weichselian loess of northwestern europe abstract the argillic horizon developed in the weichselian loesses of western europe can be related to mechanical clay translocation under a cold climate following a period of decarbonatation in several sites from brittany to southern poland where the pedostratigraphical record was preserved the bt formation can be mainly attributed to the bolling interstadial younger events exist also in the early holocene in most of these sites holocene pedogenesis is reduced to an acidification or even a podzolization in the former eluvial horizon in other sites influenced by anthropogenic activities it is difficult to analyze the chronostratigraphy of the pedological events dynamic conditions for clay translocation and stratigraphical arguments are discussed this type of argillic horizon is an early phase of pedogenesis considered to be formed under boreal climatic conditions

two new geobarometers for garnet amphibolites with applications to southeastern vermont two new geobarometers for the assemblage garnet hornblende plagioclase quartz have been calibrated on the basis of the equilibrium 6 anorthite 3 tremolite 2 grossular 1 pyrope 3 tschermakite 6 quartz and its fe end member equivalent data representing 37 natural samples that equilibrated at conditions of 2 5 to 13 kbar and 500 to 800 c were fitted to the general equation rt in keq a bt p i c by using a weighted least squares method multiple correlation coefficients are high 0 98 and 0 97 lines of constant keqhave extremely shallow slopes in p t space 2 to 8 bars per degree suggesting that pressures may be deduced precisely even where temperatures are only poorly constrained typical analytical errors and temperature imprecisions propagate to very small errors in pressure about 500 bars caution is advised in applying the barometers outside the range of calibrant mineral compositions application of the calibrations to samples from southeastern vermont near the strafford chester and athens domes documents relatively high pressure metamorphism 7 to 10 kbar for these structures

an assessment of changes in properties of steppe kurgan paleosoils in relation to prevailing climates over recent millennia comparative analysis of morphological and chemical properties of the soil chronosequence on kastanozems soils in the steppe zone of the russian plain which included paleosoils buried beneath kurgans erected ca 2000 bc ad 50 ad 200 and ad 1250 was performed to reconstruct the paleoenvironmental conditions in this archeologically important region paleoenvironmental dynamics were traced using the state of microbial communities of paleo and modern soils including the dynamics of total and glucose reactive biomass and the abundance of microorganisms grown on selected media we demonstrate that the share of the glucose reactive microorganisms in the microbial community the ecological trophic structure and oligotrophicity index might serve as indicators of the state of microbial communities and be used for paleoenvironmental reconstructions the morphological chemical and microbial properties confirm an arid period ca 2000 bc slightly wetter conditions ca ad 50 and more humid conditions ca ad 1250

magnetic susceptibility and geochemical characterization of an upper mississippian cyclothemic section polotnyanyi zavod moscow basin russia

palaeoclimatic indicators in soils buried under archaeological monuments in the eurasian steppe a review the russian experience of the local reconstruction of the eurasian steppe climate during the last 5000 years based on geoarchaeological approaches is reviewed examples of traditional palaeoclimatic reconstructions in russia based on organic matter highly soluble salts and gypsum content and location of salts and gypsum horizons in the profile of buried soils are given pedogenic carbonate as a palaeoclimatic indicator is considered the possibilities of the quantitative reconstruction of the palaeoprecipitation based on magnetic properties of buried soils are observed the innovative approach of palaeoclimatic reconstruction based on soil microbiology methods is reviewed the problem of temporary transformation of palaeoclimatic indicators in buried soils is shown a methodology for the interpretation of palaeoclimatic indicators of buried soils for a local palaeoclimatic reconstruction is given

location of natural trace elements in silty soils using particle size fractionation abstract in silty material 80 of the particles range from 2 to 50 m particle size fractionation within this size range allows determination of the main mineral bearers of natural trace elements te in silty soil three silty soils were studied at ch teau thierry in the paris basin at muret in the aquitaine basin and at thann in the alsace plain these soils mainly consist of quartz alkaline feldspars plagioclase micas and chlorite the quantities of which vary with particle size as shown by xrd and chemical analyses of major elements quartz content increases with increasing particle size whereas feldspars micas and chlorites occur mainly in the 2 10 0 2 2 and

reconstruction of the paleo environment and soil evolution of the csipo halom kurgan hungary abstract there are two explanations regarding the formation of the hungarian hortobagy steppes and associated saline areas to assess the different opinions we carried out pedological geochemical mineralogical and malacological analyses in the csipo halom csipo mound kurgan our research shows that the landscape 6000 years ago was similar to today an environmental patchwork of dry steppes wetlands and alkaline areas since the construction of the mound significant movement of chemical compounds composing the mound occurred the depths of boundary surfaces were identified through pedological studies and detailed geochemical analysis document similar signatures through time differences can be seen only in the location of the paleosoil level the soil developed on the surface of the mound is again a steppe chernozem soil formed under grass vegetation

space time variations of the frequency energy relation for mining induced seismicity in the ostrava karvina mining district the values of parameters of the relation logn a b loge characterize in general the level of seismicity of individual regions in the present paper a detailed analysis ofb values of the frequency energy distributions was carried out with the aid of a database of seismic events recorded by the seismological networks in the ostrava karvina coal mine district czech republic using the least squares regression and maximum likelihood method as well the determination ofb value was performed for a relatively large number of regions investigated and for different time series of observations special attention has been paid to induced seismic events statistics for the vicinity of one of the coalfaces in the lazy mine it could be generally stated that lowerb values correspond to a higher level of induced seismic activity while the higher ones correspond to a low and a moderate seismic activity

late holocene climate reconstructions for the russian steppe based on mineralogical and magnetic properties of buried palaeosols abstract insights into past climate changes and corresponding evolution of soils and the environment can be gained by multidisciplinary studies of palaeosols here we focus on palaeosols buried beneath archaeological monuments specifically funerary mounds kurgans in the russian steppe the kurgans were constructed and each of the palaeosols buried over a range of different timesteps from the mid holocene to 600 years before present yr bp integrated magnetic mineralogical and pedological data were used to obtain estimates of past climate especially precipitation changes through both time and space a soil magnetism based climofunction derived previously from modern steppe soils and modern climate was applied to each set of palaeosols to obtain quantitative reconstructions of annual precipitation for the time at which the soils were buried independent soil property data clay mineralogy salt content iron mineralogy from mossbauer analysis and optical and electron microscopy were also obtained in order to test and substantiate the magnetic inferences the data obtained indicate that the climate of the lower volga steppe area has varied from the mid holocene onwards precipitation minima occurred at 5000 3800 and 1600 yr bp with intervals of enhanced precipitation at 1900 yr bp and 600 yr bp these rainfall variations appear to occur synchronously with changes in middle eastern precipitation and lake levels suggesting they are controlled by index changes in the north atlantic oscillation

the development of deep soil processes in ancient kurgans of the north caucasus abstract in the past four thousand years luvisols with a clearly differentiated profile have developed on kurgans of the bronze age under beech and oak stands in humid climatic conditions of the foothills of the north caucasus the great height of the kurgans up to 10 m and their homogeneous composition the kurgans were constructed of chernozemic soil and are underlain by chernozem make it possible to study the direction and rate of pedogenetic and diagenetic processes acting at a considerable depth in these kurgans the profiles of luvisols are underlain by the carbonate illuvial horizon that has been shaped by illuviation processes acting for about 4000 years the major part of this horizon lies at the depths of 110 350 cm though carbonates penetrate as deep as 9 m along the deep earthworm burrows at this depth they occur within the noncalcareous mass of the lower part of the kurgans bodies and in the upper part of the underlying chernozem at the depth of 5 9 m in the kurgans and in the buried chernozem gypsum and iron pedofeatures nodules and red brown films on ped faces have appeared humus clayey infillings are present in some of the earthworm burrows at this depth the formation of such a deep profile with the carbonate illuvial gypsiferous and ferruginated horizons is related to the local bioclimatic conditions characterized by high precipitation and the growth of forest vegetation deep washing of the soil with atmospheric precipitation is combined with the manifestation of illuviation processes and alteration of the soil mass at a considerable depth the mineralization of humic substances and some alkalization of the soil mass also take place in the deep horizons however these processes may occur at different depths independently from the illuviation processes and can be attributed to the group of diagenetic processes

ocean floor hydrothermal metamorphism in the limousin ophiolites western french massif central evidence of a rare preserved variscan oceanic marker the limousin ophiolite is located at the suture zone between two major thrust sheets in the western french massif central this ophiolitic section comprises mantle harzburgite mantle dunite wehrlites troctolites and layered gabbros it has recorded a static metamorphic event transforming the gabbros into undeformed amphibolites and the magmatic ultramafites into serpentinites and or pargasite bearing chloritites with various thermobarometric methods it is possible to show that the different varieties of amphibole have registered low p c 0 2 gpa conditions with temperature ranging from high t late magmatic conditions to greenschist zeolite metamorphic facies the abundance of undeformed metamorphic rocks which is typical of the lower oceanic crust the occurrence of ca al mg metasomatism illustrated by the growth of ca al silicates in veins or replacing the primary magmatic minerals the p t conditions of the metamorphism and the numerous similarities with oceanic crustal rocks from ocean drilling program and worldwide ophiolites are the main arguments for an ocean floor hydrothermal metamorphism in the vicinity of a palaeo ridge among the west european variscan ophiolites the limousin ophiolites constitute an extremely rare occurrence that has not been involved in any hp subduction related or mp orogenic metamorphism as observed in other ophiolite occurrences i e france spain and germany

evidence for precursory changes in the frequency magnitude b value summary a clear case has been established for a significant increase in the slope of the frequency magnitude relation for periods of up to six years before a number of earthquakes in new zealand and california in a region of about 200 km diameter in central new zealand the b value increased from near unity to more than 2 0 at the end of 1968 and remained abnormally high until the beginning of 1975 an earthquake of magnitude 6 0 followed in 1977 january within 50 km of the location which had registered the highest b value the anomaly was detected in contour maps of b values windowed in space and time then resolved more precisely in time using the cusum technique it was statistically significant at a level higher than 99 99 per cent compared with the average rate of moment release in this region there was a deficit of 1 3 x 10 nm during the anomalous period which is equivalent to an earthquake of magnitude 6 08 this phenomenon of a high b value has been found before all shallow new zealand earthquakes of magnitude 6 0 or more since 1965 wherever the seismicity rate and detection threshold were adequate to resolve it further the only statistically significant occurrences of high b value were those which were followed by large earthquakes two of magnitude 6 8 and 6 0 and a swarm of equivalent magnitude 5 3 the phenomenon has also been found before the san fernando and coalinga earthquakes in california both of which were thrust events but it is not apparent before two large californian earthquakes with strike slip mechanisms observations of high b value are consistent with reported instances of quiescence in background seismicity in fact what has been interpreted as quiescence may probably be more accurately described as a localized high b value the duration of the anomaly is not a simple function of magnitude different strain rates in the regions examined may account for this the available data suggest that careful monitoring of the b value may provide a tool for medium term earthquake prediction although perhaps not in all tectonic environments

the state of microbial communities in buried paleosols in relation to prevailing climates in steppes of the lower volga region abstract the microbial communities of paleosols buried beneath kurgans archeological site salomatino volgogradskaya oblast russia dated to the srubnaya ca 1500 bc the late sarmatian ca ad 150 250 cultures and the golden horde time ca ad 1300 1400 and modern surface soils kastanozems and solonetzes were studied in the paleosols the amounts of viable microbial biomass constituted 40 65 aeh ae or ea horizon 27 76 bt or btn horizon and 47 287 bk horizon of the amounts in modern surface soil and reached 5 8 of total corg remained the abundances of viable microbial cells calculated from the phospholipid content in the modern surface and buried soils were similar 2 5 1010 and 1 6 2 5 x 1010 respectively the abundances of microorganisms capable of growth on selected media were 4 orders less than total numbers of viable microbial cells the regularities of the profile distribution of viable microbial biomass ecological trophic structure of microbial communities and the oligotrophy indexes in sub kurgan paleosols and their modern surface analogs were indicative for tracing the dynamics of climate humidity in the region studied the climatic conditions at the time of the srubnaya culture were more arid compared to the current time although generally this period may be considered humid the climate within the late sarmatian time was changeable arid conditions alternated with more humid ones and these periods lasted for several decades the late period of the golden horde time was characterized by more arid conditions compared to the previous humid period and the current time the microbiological data in general correspond to morphological and physicochemical properties of paleosols and in some cases might provide more detail evidence about the climate fluctuations and climatic phases of shorter duration

origin age and transformation of chernozems in northern central europe new data from neolithic earthen barrows in sw poland abstract among the clay illuviated soils dominant in the loess belt in southern poland islands of chernozemic soils are distinguished by their spectacular agricultural productivity however those soils are not marked as chernozems phaeozems in european and world soil maps due to their common excessive wetness and doubts regarding their origin well preserved earthen barrows of the funnel beaker culture discovered recently in muszkowice sw poland offer a unique possibility of pedo archaeological reconstruction the first of such in poland of the pre and post neolithic development of soil cover in loess dominated areas and explanation of the existing differentiation of soil cover into neighbouring chernozems and retisols the buried chernozemic soil phaeozem in muszkowice started to develop in the late pleistocene period mean residence time of humus 12 670 13 000 cal bp until the burial ca 5480 5310 cal bp an at least 22 cm thick mollic horizon has developed with secondary carbonates accumulation at ca 80 cm the barrow mound soil constructed entirely of initially humus rich topsoil material has transformed into retisol with fully developed thick eluvial and illuvial argic horizons and still preserved a high content of humus in the barrow mound soil profile further the surrounding soils are entirely altered into retisols with secondary carbonates starting at 135 160 cm taking into account the palynological reconstruction from the nearest pollen profile in the loess covered area a crucial importance of the open canopy mainly oak forests is concluded for the persistence of chernozems under a temperate increasingly moist climate from the early holocene to the neolithic period in turn the close canopy broadleaf forests mainly beech are considered to be responsible for the rapid transformation of chernozems phaeozems into retisols luvisols in the late holocene chernozems have persisted and probably even rejuvenated only in the areas of permanent settlement since the neolithic until the present time where human activity farming pasturing has eliminated a continuous broadleaf beech close canopy forest cover

complex pedological analysis of paleosols buried under kurgans as a basis for periodization of the timber grave archaeological culture in the southern cis ural russia abstract the problem of periodization of the timber grave culture of the late bronze age on the territory of the southern cis ural is far from being solved this situation exists because the funeral ceremony looks very similar throughout the history of the timber grave culture existence to assign stages of this culture s development a complex approach was used including archaeological observation radiocarbon dating technical and technological analysis of ceramics and study of paleosols buried under kurgans the paleopedological analysis was a key approach because the relative chronological order of the construction of kurgans was initially determined within one kurgan cemetery based on morphological observation and physical and chemical properties of the buried paleosols five kurgan cemeteries which included 19 kurgans overall of the timber grave culture were studied in the orenburg region the southern cis ural it was found that the paleosols buried under the earliest kurgans of the studied culture show the maximal values of soil bulk density in the humus and carbonate horizons the minimal content of humus in the uppermost 50 cm of the profile the highest content of carbonates and the closest to surface location of the bk horizon the highest content of gypsum and the highest portion of exchangeable sodium of the sum of exchangeable bases based on the set of mentioned properties of the buried paleosols the transitional and the latest groups of kurgans were also suggested in the latest group the paleosols show minimal values of bulk density maximal content of humus in the uppermost 50 cm minimal content of carbonates and total lack of gypsum and exchangeable sodium throughout profiles such differences in the paleosols properties buried under different groups of the timber grave kurgans were probably caused by climatic fluctuations during the period of the culture s functioning the reconstruction showed that in the most part this culture had been developed in favorable climatic conditions with a sufficient quantity of precipitation and comparatively soft climatic continentality whereas the previous period was characterized by an arid and continental climate based on archaeological observation radiocarbon dating technical and technological analysis of ceramics three chronological stages were allocated in the history of the functioning of the timber grave antiquities for the steppe cis ural according to calibrated radiocarbon dates the chronological limits are as follows the first stage xix century bc the second xviii xvii centuries bc and the third xvii xv centuries bc

late holocene climates of the near east deduced from dead sea level variations and modern regional winter rainfall the dead sea is a terminal lake of one of the largest hydrological systems in the levant and may thus be viewed as a large rain gauge for the region variations of its level are indicative of the climate variations in the region here we present the decadal to centennialresolution holocene lake level curve of the dead sea then we determine the regional hydroclimatology that affected level variations to achieve this goal we compare modern natural lake level variations and instrumental rainfall records and quantify the hydrology relative to lake level rise fall or stability to quantify that relationship under natural conditions rainfall data pre dating the artificial dead sea level drop since the 1960s are used in this respect jerusalem station offers the longest uninterrupted pre 1960s rainfall record and jerusalem rains serve as an adequate proxy for the dead sea headwaters rainfall principal component analysis indicates that temporal variations of annual precipitation in all stations in israel north of the current 200 mm yr 1 average isohyet during 1940 1990 are largely synchronous and in phase 70 of the total variance explained by pc1 this station also represents well northern jordan and the area all the way to beirut lebanon especially during extreme drought and wet spells we a determine the modern and propose the past regional hydrology and eastern mediterranean em climatology that affected the severity and length of droughts wet spells associated with multiyear episodes of dead sea level falls rises and b determine that em cyclone tracks were different in average number and latitude in wet and dry years in jerusalem the mean composite sea level pressure and 500 mb height anomalies indicate that the potential causes for wet and dry episodes span the entire em and are rooted in the larger scale northern hemisphere atmospheric circulation we also identified remarkably close association within radiocarbon resolution between climatic changes in the levant reflected by level changes and culture shifts in this region

grain growth and transformation of pedogenic magnetic particles in red ferralsols soil magnetism depends on the mineral composition and grain size distribution of magnetic particles the accumulation of magnetic particles with different grain sizes has been found in the laboratory to precede the formation of hematite hm which competes with goethite gt in natural systems to explore changes in the correlation between magnetic particles and hm during pedogenesis we focus on three representative red ferrasol profiles with comparable total concentrations of iron oxides but different hm hm gt ratios from 0 14 to 0 74 superparamagnetic particles and single domain particles commonly become enriched as the concentration of hm increases in the profiles however the accumulation rates of the particles decrease with hm hm gt along the profiles we attributed these changes to the simultaneous grain growth of pedogenic magnetic particles and their partial transformation into hm once a large amount of pedogenic magnetic particles have accumulated in hematitic soils

a preliminary magnetic study of soil samples from west central minnesota abstract various rock magnetic techniques were applied to characterize magnetically the samples of a soil profile taken from west central minnesota there is a marked change in magnetic properties as a function of depth in the core x ray analysis and curie temperature measurements carried out on the magnetic fractions indicate that magnetite is the dominant iron oxide in both the top soil and the subsoil the intensity of anhysteretic remanent magnetization arm decreases sharply as the depth increases in contrast the stability of arm was found to be higher for the subsoil the surface soil sample was capable of acquiring a significant amount of viscous remanent magnetization vrm the vrm acquisition coefficient s a of the subsoil s a 3 18 10 6 emu g 1 3 18 10 6 a m 2 kg 1 was about ten times weaker than that of the top soil sample s a 3 868 10 7emu g 1 3 868 10 7 a m 2 kg 1 the magnetic domain state indicator the ratio of coercivity of remanence to coercive force h cr h c was 1 5 and 3 85 for the top soil and subsoil respectively it appears that the observed variations in magnetic properties down the present soil core is due only to a difference in grain size we conclude that the magnetic grains in surface soil samples were more single domain sd like whereas the magnetite grains in the subsoil samples were more likely in pseudo single domain psd or small multidomain md range the observed lower stability for the surface soil samples is attributed to the presence of superparamagnetic grains whose presence was confirmed by transmission electron micrographs

viable paleosol microorganisms paleoclimatic reconstruction and relative dating in archaeology a test case from hell gap wyoming usa living soil microorganisms are ubiquitous and could provide unrealized contributions to paleoenvironmental dating and other archaeological research we evaluated the effectiveness of a previously proposed microbiological technique for paleoclimatic reconstruction which has been applied but not adequately verified and also introduced and tested a preliminary method of using soil microbe density for relative dating soils from a sample column representing a complete chronosequence at hell gap locality i wyoming were cultured on three different solid media to test the paleoclimatic reconstruction method trophic group data were tested for serial correlation and compared to soil and phytolith analyses formerly completed at the site microbial trophic group composition significantly correlated to soil ph but not to prior precipitation reconstructions further refinement is required before the paleoclimatic reconstruction method can be implemented with confidence additionally microbial density decreased with age suggesting a temporal signature within the sample column and that density could potentially be used as a relative dating technique

magnetic properties of modern soils and quaternary loessic paleosols paleoclimatic implications the magnetic properties of paleosols developed in quaternary sequences of loess have been used for stratigraphic definition correlation with other terrestrial and deep sea sequences and paleoclimatic paleorainfall reconstruction in some loess paleosol sequences including those of the chinese loess plateau tajikistan and the czech republic maxima in magnetic susceptibility values correspond with the paleosol horizons and minima with the least weathered loess layers in other loess soil sequences including those of siberia alaska and argentina the relationship is completely opposite with susceptibility minima associated with the most developed paleosols to account for these opposite relationships the respective roles of 1 magnetic enhancement and 2 magnetic depletion and or dilution in determining soil magnetic properties are investigated for a range of modern soil types most magnetic enhancement is seen in the upper horizons of well drained cambisols absence or loss of magnetic iron oxides is apparent in acid podsol profiles and waterlogged soils for the cambisol profiles significant correlation is found between susceptibility and organic carbon cation exchange capacity and clay content the mineralogy morphology and grain size of soil magnetic carriers extracted from three modern enhanced soils and a paleosol from the chinese loess plateau are also identified by independent petrographic means microscopy and x ray diffraction of magnetic extracts magnetite and maghemite of ultrafine grain size from 0 4 to 0 001 i m are the major contributors to the magnetically enhanced soils weathering can concentrate detrital magnetic grains especially in the fine silt size fractions of soils the magnetic data from the modern soils indicate that interpretation of paleosol magnetic properties must be done on a site specific basis taking into account the possibilities of pedogenic enhancement pedogenic dilution or depletion and allochthonous inputs of magnetic minerals excessively arid wet or acid soils are unable to form significant amounts of pedogenic ferrimagnets well drained intermittently wet dry soils with reasonable buffering capacity and a substrate source of fe show most magnetic enhancement for those soils which favour magnetic enhancement processes correlation has been found between the maximum value of the pedogenic susceptibility and the annual rainfall the almost unique pedogenic system in the chinese loess plateau where variation in soil forming factors other than climate is reduced to a global minimum allows use of the paleo susceptibility values as proxy paleorainfall values to identify the mechanism of any link between magnetic properties for example susceptibility and climate change the mineralogy and grain size of soil magnetic carriers requires detailed investigation given the prospect of 1 quantitative paleorainfall records from continental loess records 2 predictions of present and future climate change and 3 the value of paleoclimate data for testing of numerical climate models such magnetic investigations can contribute significantly to our understanding of past and future environmental change

plio pleistocene paleosols loess paleosol sequence studied in the beregovoye section the crimean peninsula abstract the loess paleosol sequence exposed in the beregovoye section southwest of the crimean peninsula has been thoroughly studied detailed analysis of the paleosol morphology physical properties and chemical composition micromorphology and other characteristics made it possible to identify types of paleosols formed in the pliocene and pleistocene the results obtained gave us an insight into the climate and environments of the past according to them the climate of the pliocene optimum was extremely hot and wet and the soil zonality was hardly pronounced practically over entire central and eastern europe at the final phase of the pliocene the climate became drier though the rainfall amount was still greater than in the holocene during the early pleistocene the soil development followed the mediterranean type the climate being still warm though less humid than in the pliocene there are two peaks of catastrophic changes in the evolution of the climate and environments distinctly traceable in the beregovoye section first corresponding to the global change recorded between the pliocene and pleistocene and second falling on the initial phase of the modern holocene soil formation

nature and age of pre variscan eclogite protoliths from the low to medium grade metamorphic complex of north central sardinia italy and comparisons with coeval sardinian eclogites in the northern gondwana context u pb zircon data on retrogressed eclogites sampled in the giuncana locality from the sardinian medium grade metamorphic complex yielded a weighted age of 454 6 ma this is in agreement with u pb zircon ages of 453 460 ma obtained from eclogites from the high grade metamorphic complex the giuncana eclogites are very similar to the other well known sardinian eclogites all of the sardinian eclogites show positive k rb ba u and pb anomalies and negative nb la ce and sr anomalies th is depleted in the giuncana eclogites and enriched in those from punta de li tulchi and punta tittinosu all these data reveal clear crustal contamination of the sardinian ordovician mantle ree patterns typical of normal mid ocean ridge basalt n morb characterize all of the sardinian eclogites the supply of crustal and calc alkaline materials to the sardinian mantle during the ordovician is further confirmed by the fact that most sardinian eclogites plot on the left side and well above the mantle array in a th yb v nb yb diagram in the general variscan framework of northern gondwana the sardinian eclogites are witness to the most recent back arc basins generated by the northward opening of the rheic ocean

palaeoenvironments of the middle late mississippian moscow basin russia from multiproxy study of palaeosols and palaeokarsts abstract numerous pedogenically altered subaerial exposure surfaces within middle late mississippian visean serpukhovian shallow carbonates in the moscow basin attest to sea level fluctuations and climate change in total fifteen palaeosols at seven stratigraphical levels from five open pits were described and studied in detail they show both stratigraphic and lateral soil type variability the factors of major influence are substrate type time of exposure tectonics and relief and climate all palaeosols are polycyclic and consist of at least two parts the lower unit substrate consisting mainly of limestone with siliciclastic deltaic and palustrine beds was altered to different degrees by weathering pedogenesis depending on climate the limestone was transformed into calcrete or caliche the substrate is capped by a terrigeneous topclay which represents an individual palaeosol developed prior to subsequent marine flooding indications of gley conditions as well as the presence of coal sphaerosiderite and framboidal pyrite indicate a wet peat swamp environment that was however periodically dry the calculated mean annual precipitation map based on a cia k proxy of siliciclastic units shows that the climate was characterized by alternating periods of aridity and humidity with the most humid conditions 1250 mm during the middle visean the same proxy applied to late mississippian sediments of the appalachian basin shows a similar map range high amplitude sea level fluctuations at the mikhailovian venevian boundary followed by prolonged exposure resulted in the development of a laterally extensive deep karst capped by a pedocomplex and then by a palustrine bed the structure and scale of this unconformity are comparable to those of the florida everglades environment which represents a modern marsh landscape the majority of topclays are smectitic except for the most humid and most arid environments which are dominated by kaolinite and palygorskite respectively besides mineralogy we also provide data regarding geochemistry carbon isotopic composition of carbonate organic matter characteristics including solid state 13 c nmr and 13 c data and evidence of vegetation types based on field observations and sem images

biomorphic analysis as a part of soil morphological investigations abstract biomorphic analysis is the microscopic investigation of plant tissue detritus phytoliths pollen and other remains of biota for the reconstruction of ancient pedogenic conditions and the evolution of soils each biomorph is associated with certain types of landscape and provides information on conditions of soil development and on landscape evolution every stage of soil development forms its own biomorph profile and profiles of different stages can be distinguished they indicate the main vegetation changes during the holocene human impacts such as grazing tillage and tree felling also exert a considerable influence on the qualitative and quantitative distribution of biomorphs through the profile as examples samples were studied from soil profiles representing different climatic subzones of the russian plain the results show that biomorphic analyses can provide information that is otherwise unobtainable and can elucidate some controversial questions of soil genesis and cultural changes