spatial variability of hydraulic conductivity and bulk density along a blanket peatland hillslope this article presents the results of a field investigation of saturated hydraulic conductivity ksat and bulk density bd in an atlantic blanket bog in the southwest of ireland starting at a peatland stream and moving along an uphill transect toward the peatland interior bd and ksat were examined at regular intervals saturated horizontal hydraulic conductivity khsat and vertical kvsat was estimated at two depths 10 20 and 30 40 cm below the peat surface whereas bd was estimated for the full profile we consider two separate zones one a riparian zone extending 10 m from the stream and a second zone in the bog interior we found that the ksat was higher 10 5 m s 1 in the bog interior than that in the riparian zone 10 6 m s 1 whereas the converse applied to bulk density with lowest density 0 055 g cm 3 at the interior and highest 0 11 g cm 3 at the riparian zone in general we found khsat to be approximately twice the kvsat these results support the idea that the lower ksat at the margins control the hydrology of blanket peatlands it is therefore important that the spatial variation of these two key properties be accommodated in hydrological models if the correct rainfall runoff characteristics are to be correctly modelled stream flow analysis over 3 years at the peatland catchment outlet showed that the stream runoff was composed of 8 base flow and 92 flood flow suggesting that this blanket peatland is a source rather than a sink for floodwaters copyright 2011 john wiley sons ltd

macroporosity and infiltration in blanket peat the implications of tension disc infiltrometer measurements little is known about the processes of infiltration and water movement in the upper layers of blanket peat a tension infiltrometer was used to measure hydraulic conductivity in a blanket peat in the north pennines england measurements were taken from the surface down to 20 cm in depth for peat under four different vegetation covers it was found that macropore flow is a significant pathway for water in the upper layers of this soil type it was also found that peat depth and surface vegetation cover were associated with macroporosity and saturated hydraulic conductivity the proportion of macropore flow was found to be greater at 5 cm depth than at 0 10 and 20 cm depth peat beneath a sphagnum cover tends to be more permeable and a greater proportion of macropore flow can occur beneath this vegetation type functional macroporosity and matrix flow in the near surface layers of bare peat appear to have been affected by weathering processes comparision of results with rainfall records demonstrates that infiltration excess overland flow is unlikely to be a common runoff generating mechanism on blanket peat rather a saturation excess mechanism combined with percolation excess above much less permeable layers dominates the runoff response copyright 2001 john wiley sons ltd

highly evolved juvenile granites with tetrad ree patterns the woduhe and baerzhe granites from the great xing an mountains in ne china abstract in ne china voluminous granitoids were emplaced in late paleozoic and mesozoic times we report here sr nd o isotopic and elemental abundance data for two highly evolved granitic plutons woduhe and baerzhe from the great xing an mountains they show a rather juvenile sr nd isotopic signature and a spectacular tetrad effect in their ree distribution patterns as well as non charac charge and radius controlled trace element behavior the emplacement ages are constrained at 130 4 ma for the woduhe and 122 5 ma for the baerzhe granites by rb sr and sm nd isotope analyses both granites are also characterized by low but imprecise initial 87sr 86sr ratios of about 0 703 the nd sr isotope data argue for their generation by melting of dominantly juvenile mantle component with subordinate recycled ancient crust this is largely compatible with the general scenario for much of the phanerozoic granitoids emplaced in the central asian orogenic belt the parental magmas for both the woduhe and baerzhe granites have undergone extensive magmatic differentiation during which intense interaction of the residual melts with aqueous hydrothermal fluids probably rich in f and cl resulted in the non charac trace element behavior and the tetrad effect of ree distribution both the woduhe and baerzhe granites show the characteristic trace element patterns of rare metal granites but their absolute abundances differ by as much as two orders of magnitude the oxygen isotope compositions of the two granites have been severely disturbed significant 18o depletion in feldspar but not so much in quartz suggests that the hydrothermal alteration took place in a temperature condition of 300 500 c this subsolidus hydrothermal alteration is decoupled from the late stage magma fluid interaction at higher temperatures despite the two distinct and intense events of water rock interaction the rb sr and sm nd geochronological systems seem to have maintained closed hence suggesting that the two events occurred shortly after the plutonic emplacements

morphology structure and flow phases in soil pipes developing in forested hillslopes underlain by a quaternary sand gravel formation hokkaido northern main island in japan preferential flow pathways such as soil pipes are usually present in the soil of slopes subsurface flow through the soil pipes affects the subsurface drainage system and is responsible for sediment removal from slopes however a record of the inner structure of soil pipes has rarely been reported for slopes a fibrescope examination of the morphology and flow phases in soil pipes in hillslopes underlain by a quaternary sand gravel formation provided the following information the main pores of the soil pipes ran mostly parallel with the slope gradient the cross sections of the soil pipes were approximately circular and occurred on a few occasions with some triple junctions being present in addition both full flow and partly full depth conditions occurred simultaneously in the soil pipe the full flow condition has long been used in hydrological studies to model the pipe flow mechanism both the full flow condition and the partly full depth condition however must be examined closely in order to evaluate the subsurface hydrology in heterogeneous soil and the hydrogeomorphological processes of subsurface hydraulic erosion copyright 2000 john wiley sons ltd

he ar and s isotopic constraints on the relationship between a type granites and tin mineralization a case study of tin deposits in the tengchong lianghe tin belt southwest china abstract the tengchong lianghe tin belt in western yunnan province southwest china is the most important tin mineralization belt in the sanjiang tethyan metallogenic domain stmd there are two large tin deposits in this belt the paleogene lailishan and the late cretaceous xiaolonghe deposits the two deposits are spatially and temporally associated with the lailishan and xiaolonghe granitic plutons respectively recent studies suggest that the lailishan and xiaolonghe granitic plutons exhibit most of the mineralogical and geochemical characteristics of a type granites in this study we discuss the he ar and s isotopes of pyrite samples from the two large tin deposits to trace ore forming fluids and elements we also review the relationship between a type granites and tin deposits from a new perspective the 34scdt values of the lailishan tin deposit range from 4 9 to 6 7 with an average value of 5 53 the 34scdt values of the xiaolonghe tin deposit range from 5 0 to 8 1 with an average value of 6 33 these values are slightly higher than those of the granites 0 to 5 7 in the tengchong lianghe area indicating mainly magmatic sources for the sulfur of ore forming fluids with a small amount of s from the wall rocks the lailishan tin deposit has 3he 4he values of 1 57 3 46 ra with an average value of 2 078 ra and 40ar 36ar values of 382 00 622 99 with an average value of 459 67 the xiaolonghe tin deposit has 3he 4he values of 0 53 0 88 ra with an average value of 0 686 ra and 40ar 36ar values of 301 06 348 43 with an average value of 322 04 these values suggest that ore forming fluids of the lailishan and xiaolonghe tin deposits have mixed crustal mantle and a small volume of meteoric water sources in different proportions the mantle 4he values and 3he 4he values of the lailihsan tin deposit 26 44 1 57 3 46 ra are markedly higher than those of the xiaolonghe tin deposit 8 15 0 53 0 88 ra implying increased crust mantle interaction in the paleogene relative to the late cretaceous in western yunnan this interaction may be attributed to the upwelling of the asthenosphere through the break off of the neo tethyan slab during the main collisional period 65 41 ma of india asia

origin of the cenozoic mesozoic magnetite series and ilmenite series granitoids in east asia abstract among the phanerozoic granitoids of east asia the most prevailing cenozoic mesozoic rocks are reviewed with respect to gabbro granite ratio bulk composition of granitoids redox state and o and sr isotopic ratios quaternary volcanic rocks ranging from basalt to rhyolite but typically felsic andesite in terms of bulk composition in island arcs are oxidized type possibly due to oxidants from subducting oceanic crust into the source regions miocene plutonic rocks in the back arc of japan could be a root zone for such volcanism but are more felsic in composition cenozoic mesozoic plutonic zones are classified by 1 the redox state magnetite ilmenite series and 2 average bulk composition granodiorite granite the granodioritic magnetite series occur with fairly abundant gabbro and diorite in the back arc of island arcs greentuff belt and intercontinental rapture zones yangtze block these rocks are mostly juvenile in terms of the 87sr 86sri and 18o values the granitic magnetite series with some gabbroids occur in rapture zones along the continental coast gyeongsang basin fujian coast and the back arc of island arc sanin belt they were generated mostly in felsic continental crust with the help of heat and magmas from upper mantle the generated granitic magmas had little interaction with c and s bearing reducing materials due probably to extensional tectonic settings the 18o value gives narrow ranges but the 87sr 86sri ratio varies greatly depending upon the age and composition of the continental crust granitic ilmenite series are characterized by high 18o values implying much contribution of sediments the 87sr 86sri ratios are low in island arcs but very high in continental interior settings amount of mafic magmas from the upper mantle seems a key to control the composition of granitoid series in island arc settings while original composition of the protolith may be the key to control granitoid composition in continental interiors

mid holocene sub blanket peat alluvia and sediment sources in the upper liffey valley co wicklow ireland a recently exposed section across a rst order valley buried beneath the regional blanket peat on hillside slopes in the upper liffey valley co wicklow is described the section shows two alluvia within a shallow valley form underlain by an extensive boulder and stone line over regional till and weathered granite 14c dates from wood in the alluvia indicate the older alluvium to have formed between 4324 53 bp and 4126 45 bp and the younger between 3217 53 bp and 2975 53 bp the basal layer of the overlying peat yielded a date of 2208 61 bp the younger alluvium shows the effects of soil paludi cation prior to the peat expansion dated pollen analyses elsewhere in the upper catchment con rm the spread of blanket peat over most areas above 350 m after 4000 3600 bp the buried valley was contributing sediments to the mid holocene oodplains in the upper liffey valley prior to the extension of blanket peat over the catchment after which sediment yields from it and the other catchment slopes declined copyright 2003 john wiley sons ltd

oxygen isotopic constraints on the geneses of the miocene outer zone granitoids in japan abstract miocene ilmenite series granitoids of the outer zone of southwest japan have been classified mineralogically into the southern s type and the northern i type oxygen isotopic ratios 18 o smow were determined on 45 representative samples from 17 granitic plutons the results indicate that the outer zone granitoids have much higher 18 o values than magnetite series granitoids of similar ages confirming a contribution from crustal sediments to the genesis of the ilmenite series granitoids and that s type granitoids are higher than i type with separation at 10 5 which is slightly higher than the 9 7 boundary in the lachlan fold belt of australia assuming the granitoids originated from mixtures of basaltic magmas from the upper mantle and sedimentary rocks of the accretionary complex from the fore arc basin mixing ratios were calculated the s type granitoids have sedimentary contributions of 64 45 wt with one exception while i type granitoids have that of 43 30 wt two trends are typically observed in the 18 o sio 2 diagram i granitoids having large variation in 18 o values but little variation in sio2 contents and ii vice versa the former granitoids solidified from heterogeneous magmas containing restite fragments but the latter crystallized from a completely homogenized magma with magmatic fractionation this type is associated with mineralization

numerical calculation of soil pipe flow and its effect on water dynamics in a slope a chain of connected macropores which develops nearly parallel to the impermeable subsurface layer is commonly found in hillslopes and referred to as a soil pipe field observations have revealed that water flow in such a pipe pipe flow has large hydrogeomorphic effects since it contributes to rapid transfer of storm water and subsurface soil erosion this study proposed a simple simulation method to describe water dynamics in a piped hillslope the applicability of the method was examined using data obtained from a bench scale experiment using pseudo soil pipes results of the experiment showed that 1 the flume bed pore water pressure became small around the upper ends of the pipes 2 when pipe outlets were connected to a stream channel the open pipe condition the flume bed pore water pressures in the whole slope were much lower than those under the no pipe condition 3 when pipe outlets were not connected to a stream channel the closed pipe condition the flume bed pore water pressure at the pipe outlets was higher than that under the no pipe condition these results were reproduced by solving the two dimensional richards equation assuming an equivalent soil matrix layer for the original pipes plus soil matrix part which had a larger saturated hydraulic conductivity than the surrounding soil matrix this simple simulation method has an advantage over previous pipe flow models both the pipe flow and the interaction between the soil pipes and the surrounding soil matrix can be computed by solving the richards equation without using any further assumptions for the boundary conditions between the soil pipes and the soil matrix results of numerical experiments using the simple method showed that 1 under the closed pipe condition the flume bed pore water pressure at the pipe outlets increased as the pipe length increased and 2 once the open pipes clogged flume bed pore water pressures in the whole slope increased and the greatest increase occurred at the boundary between the clogging and non clogging parts copyright 2004 john wiley sons ltd

petrogenesis of metaluminous a type granitoids in the tengchong lianghe tin belt of southwestern china evidences from zircon u pb ages and hf o isotopes and whole rock sr nd isotopes abstract the tengchong lianghe tin belt is the most importantpart of the tin metallogenic belt in southwest china s sanjiang metallogenic province in this district two a type granite plutons that are spatially associated with the tin deposits have recently been discovered these granitoids are dominated by biotite granites with weakly peraluminous to metaluminous compositions high sio2 contents 73 3 76 2 wt and high alkali contents k2o na2o 8 3 9 17 wt trace element spider diagrams show that these granitoids are also clearly enriched with the large ion lithophile elements rb th u and k but are markedly depleted in ba and sr they are significantly depleted in the high field strength elements nb and ti but are enriched with zr and hf these rocks have relatively high zircon saturation temperatures 774 833 c high zr nb ce y contents 272 416 ppm and 10 000 ga al ratios almost 2 7 that are typical of a type granites they also have high total rare earth element ree contents 174 404 ppm and relatively flat chondrite normalized ree patterns with significantly negative eu anomalies la icp ms zircon u pb dating results indicate that the emplacement of these two granite plutons occurred during the early tertiary 52 7 0 3 53 0 0 4 ma and the late cretaceous 73 3 0 5 73 3 0 5 ma periods respectively isotopic compositions show that the granitoids have highly variable 87sr 86sr i ratios 0 7182 0 7457 relatively constant low end t values 11 2 to 12 4 and ancient nd and hf model ages 1 56 1 88 ga suggesting that they were derived from the partial melting of the paleoproterozoic continental crust their zircon 18o values 6 6 8 5 and ehf values from 8 6 to 11 3 also suggest that these granitoids mainly originated from the middle lower continental crust consisting of mafic and metasedimentary rocks such geochemical characteristics indicate that these two a type granite plutons were generated by the partial melting of paleoproterozoic mafic and the metasedimentary basement of the tengchong block in a post collisional or syn collisional extensional setting of the neo tethy anorogenic zone during the late cretaceous early cenozoic the late cretaceous granitoids were probably associated with the subduction of the neo tethyan plate under the post collisional extension of the western burma and tengchong microplates collision during the jurassic early cretaceous the early tertiary granitoids might be the syn collisional product of stretching relaxation during the middle and late main collisional period 55 41 ma between india and asia

topographic controls upon soil macropore flow macropores are important components of soil hydrology the spatial distribution of macropore flow as a proportion of saturated hydraulic conductivity was tested on six humid temperate slopes using transects of tension infiltrometer measurements automated water table and overland flow monitoring allowed the timing of and differentiation between saturation excess overland flow and infiltration excess overland flow occurrence on the slopes to be determined and related to tension infiltrometer measurements two slopes were covered with blanket peat two with stagnohumic gleys and two with brown earth soils none of the slopes had been disturbed by agricultural activity within the last 20 years this controlled the potential for tillage impacts on macropores the proportion of near surface macropore flow to saturated hydraulic conductivity was found to vary according to slope position the spatial patterns were not the same for all hillslopes on the four non peat slopes there was a relationship between locations of overland flow occurrence and reduced macroporosity this relationship did not exist for the peat slopes investigated because they experienced overland flow across their whole slope surfaces nevertheless they still had a distinctive spatial pattern of macropore flow according to slope position for the other soils tested parts of slopes that were susceptible to saturation excess overland flow e g hilltoes or flat hilltops tended to have least macropore flow to a lesser extent for the parts of slopes susceptible to infiltration excess overland flow the proportion of macropore flow as a component of infiltration was also smaller compared with the rest of the slope the roles of macropore creation and macropore infilling by sheet wash are discussed and it is noted that the combination of these may result in distinctive topographically controlled spatial patterns of macropore flow copyright 2008 john wiley sons ltd

chemical dilation and the dual porosity of humified bog peat abstract hydrochloric acid and calcium and sodium chloride salt solutions were passed through humified bog peat cores of 1 m length to determine values for the material properties governing solute transport hydraulic conductivity effective porosity and dispersivity chloride passed through the bulk peat cores about twice as fast as predicted from chloride breakthrough curves measured by selective ion probes inserted into the peat 30 cm downgradient from the source with continued experimentation chloride dispersion increased chloride also passed through the peat up to 12 times slower than predicted by conservative advection the retardation of the chloride fronts the faster bulk transport and the asymmetry of the breakthrough curves all indicate that humified bog peat is a dual porosity medium solutes both move preferentially through active macropore spaces and diffuse into dead pore space in the peat matrix neither the effective porosity nor the dispersivity of the peat could be precisely determined from the breakthrough curves because the hydraulic conductivity and discharge rates through the peat increased as much as five times when the chloride tracer solutions passed through the cores in initial experiments the shapes of the breakthrough curves were generally consistent with dispersivities of the order of centimeters similar to that observed for granular soils at the same length scale meters whereas they flattened considerably during later experiments suggesting dispersivities in the range of tens of centimeters we hypothesize that the interaction of the chloride tracer solutions with organic acid functional groups may cause macropores to dilate and micropores to close off

configuration of the moho discontinuity beneath the japanese islands derived from three dimensional seismic tomography abstract the mohorovicic discontinuity moho is defined on the basis of an abrupt increase in seismic velocity in the lithosphere which has been observed using seismic refraction and receiver function analysis methods worldwide moho depth varies regionally and remains a fundamental parameter of crustal structure we present a new method of mapping the moho using a 3d seismic tomography model since the tomographic method cannot locate discontinuities we treat the moho as a zone of high velocity gradient maximum lower crust minimum upper mantle p wave velocities in japan are known to be 7 0 km s and 7 5 km s respectively we map the residual between isovelocity surfaces of 7 0 km s and 7 5 km s to find areas where the residual is small the separation between the surfaces is narrow and the velocity gradient is high the moho is best constrained where the isovelocity surfaces are close together and under much of japan they are 10 km apart we chose an isovelocity surface of 7 2 km s as a representative moho proxy in these areas our resulting moho map under japan compares favorably with existing regional moho models that were obtained from controlled source seismic investigations the moho varies from shallow 25 30 km to deep 30 km and this variability relates to the structural evolution of the japanese islands the opening of the sea of japan back arc ongoing arc arc collisions at the hidaka and izu collision zones ongoing back arc extension in kyushu and a possible failed back arc extensional event of mesozoic age it is apparent that the moho is less well constrained in areas where the crustal structure has been modified by magmatic activity or thickened due to arc arc collision

overland flow velocity and roughness properties in peatlands overland flow is an important component of peatland hydrology hydrological models of peatlands are being developed that require estimates of flow velocity and its controls however surprisingly little is known about overland flow velocities in peatlands some peatlands have also been drained using open ditches and these need to be incorporated into flow models this paper presents field data on the velocity of overland flow and drain flow in upland peatlands the relationships between flow velocity vegetation cover slope and water depth are explored sphagnum provided a significantly greater effective hydraulic roughness to overland flow than peatland grasses in all cases a significant break in process occurred for flows with water depths of around 1 cm so that there were two components of the roughness curve this is consistent with partial submergence theory for very shallow flows where resistance increases with depth as the soil surface first becomes fully submerged while each surface cover type should be considered separately the results also suggest that a first order estimate of darcy weisbach roughness and mean velocity can be based on a single parameter for each surface cover this paper presents an empirical overland flow velocity forecasting model that can be applied to peatlands the model combines the partially submerged component for flows with water depths below 1 cm with the fully submerged component for flows with depths up to 5 cm which are representative of the depths of flows that occur across peatlands

evidence for significant clockwise rotations of the korean peninsula during cretaceous abstract in an effort to evaluate the cretaceous magnetostratigraphy for the korean peninsula and to establish the tectonic coherence of its various elements we collected paleomagnetic data from 121 samples from 20 sites within the chilgok formation 108 3 109 9 ma in the gyeongsang basin together with previously published data we evaluate the results from a total of 163 sites in the basin we combine our age model with results from recent stratigraphic paleomagnetic and radiometric geochemical studies in this study we found that two distinct declination shifts decrease with younging direction indicating two clockwise rotational events of the korean peninsula with respect to the eurasia continent the earlier event took place during 130 100 ma phase i newly termed goguryeo disturbance and a later one during 80 50 ma phase iii belonging to bulguksa orogeny the mean rotation rate in the interval from 115 2 to 103 8 ma phase i is about 0 74 ma while the rate from 90 9 to 79 8 ma phase ii is 0 19 ma based on paleolatitude change during phase i we infer that the korean peninsula eastern part of the sino korea block migrated southward about 300 km after the complete amalgamation of the sino korea block into the eurasian continent resulting in n s compression within the korean peninsula and manchuria large scale strike slip faults e g tan lu fault okcheon boundary fault were probably rejuvenated in the sino korea block during phase i

mantle flow induced crustal thinning in the area between the easternmost part of the anatolian plate and the arabian foreland e turkey deduced from the geological and geophysical data abstract eastern anatolia consisting of an amalgamation of fragments of oceanic and continental lithosphere is a current active intercontinental contractional zone that is still being squeezed and shortened between the arabian and eurasian plates this collisional and contractional zone is being accompanied by the tectonic escape of most of the anatolian plate to the west by major strike slip faulting on the right lateral north anatolian transform fault zone natfz and left lateral east anatolian transform fault zone eatfz which meet at karliova forming an east pointing cusp the present day crust in the area between the easternmost part of the anatolian plate and the arabian foreland gets thinner from north ca 44 km to south ca 36 km relative to its eastern eahp and western sides central anatolian region this thinner crustal area is characterized by shallow cpd 12 16 km very low pn velocities

anisotropy and depth related heterogeneity of hydraulic conductivity in a bog peat ii modelling the effects on groundwater flow anisotropy and heterogeneity of hydraulic conductivity k are seldom considered in models of mire hydrology we investigated the effect of anisotropy and heterogeneity on groundwater flow in bog peat using a steady state groundwater model in five model simulations four sets of k data were used the first set comprised measured k values from an anisotropic and heterogeneous bog peat these data were aggregated to produce the following simplified data sets an isotropic and heterogeneous distribution of k an isotropic and homogeneous distribution and an anisotropic and homogeneous distribution we demonstrate that where anisotropy and heterogeneity exist groundwater flow in bog peat is complex fine scale variations in k have the potential to influence patterns and rates of groundwater flow however for our data at least it is heterogeneity and not anisotropy that has the greater influence on producing complex patterns of groundwater flow we also demonstrate that patterns and rates of groundwater flow are simplified and reduced when measured k values are aggregated to create a more uniform distribution of k for example when measured k values are aggregated to produce isotropy and homogeneity the rate of modelled seepage is reduced by 28 we also show that when measured k values are used the presence of a drainage ditch can increase seepage through a modelled cross section our work has implications for the accurate interpretation of hydraulic head data obtained from peat soils and also the understanding of the effect of drainage ditches on patterns and rates of groundwater flow

hydraulic conductivity in upland blanket peat measurement and variability a key parameter used in wetland hydrological and landform development models is hydraulic conductivity head recovery tests are often used to measure hydraulic conductivity but the calculation techniques are usually confined to rigid soil theory this is despite reports demonstrating the misapplication of rigid soil theory to non rigid soils such as peats while values of hydraulic conductivity calculated using compressible techniques have been presented for fenland peats these data have never to the authors knowledge been compared to such calculations in other peat types head recovery tests slug withdrawal were performed on piezometers at depths ranging from 10 cm to 80 cm from the surface on north pennine blanket peats results were obtained using both rigid and compressible soil theories allowing comparison of the two techniques compressible soil theory gives values for hydraulic conductivity that are typically a factor of five times less than rigid soil calculations hydraulic conductivity is often assumed to decrease with depth in upland peats but at the study site in the northern pennines it was not found to vary significantly with depth within the range of peat depths sampled the variance within depth categories was not significantly different to the variance between depth categories showing that individual peat layers did not have characteristic hydraulic conductivity values thus large lateral and vertical differences in hydraulic conductivity over short distances creates problems for modelling but may help account for the high frequency of preferential flow pathways within what is otherwise a low matrix hydraulic conductivity peat hydraulic conductivity was found to vary significantly between sampling sites demonstrating that hillslope or catchment scale variability may be more important than plot scale variability values for compressibility of the peats are also reported these generally decline with depth and also vary significantly between sampling sites there are implications for the way in which measurements of hydraulic conductivity and other properties of blanket peat are interpreted as the effects of environmental change in one part of a peat catchment may be very different to those in another

mineral chemistry trace elements and sr nd hf isotope geochemistry and petrogenesis of cailing and furong granites and mafic enclaves from the qitianling batholith in the shi hang zone south china abstract the shi hang zone is an important ne trending mesozoic magmatic belt composed of granites with relative high end t values and young tdm model ages in south china however the petrogenesis and the tectonic environment for the shi hang zone magmatic rocks remain controversial we report here mineral chemistry geochemical and sr nd hf isotopic data for the cailing and furong granites and mafic microgranular enclaves mmes from the qitianling granite batholith in southern hunan province south china the qitianling granite batholith is a multi staged composite pluton with three phases cailing furong and huangtangling according to their ages and petrography the cailing 163 160 ma and furong 157 153 ma phases are mainly composed of porphyritic amphibole biotite monzogranite and they share similar geochemical and isotopic characteristics both of them show similar sio2 contents from 66 50 to 70 28 and metaluminous a cnk values of 0 80 to 0 98 the granites are characterized by high contents of large ion lithosphile elements lile such as rb th u pb high field strength elements hfse such as nb ta zr hf and zr nb ce y contents 350 ppm and high 10 000 ga al ratios 2 6 chondrite normalized ree patterns show relative enrichment of light rare earth elements lrees and significant negative eu anomalies mineralogical and geochemical features suggest that the cailing and furong granites are a type which can be further classified as a2 subtype they have relatively lower 87sr 86sr i ratios 0 7091 0 7132 higher end t values 5 5 to 7 6 and younger nd isotopic model ages 1 48 1 56 ga than those common s type granites in south china zircon ehf t values vary from 8 1 to 3 7 the mmes in the cailing phase show similar trace element and sr nd isotopic characteristics with the host granites but zircons from the mmes show different ehf t values 6 4 2 6 with those from the host granites 8 1 to 3 7 this indicates that the mmes and host granites were crystallized from different sources of magmas providing direct evidence for mafic felsic magma mixing processes the isotope data indicate that the cailing and furong granites from the qitianling batholith were derived from a hybrid magma consisting of about 80 felsic magma derived from old crust and about 20 mantle derived mafic magma the strong magma mixing at about 160 155 ma caused by intra arc rifting or back arc extension related to subduction of the paleo pacific plate is favored to explain the petrogenesis of the cailing and furong granites as well as the shi hang zone

characteristics of the early cretaceous igneous activity in the korean peninsula and tectonic implications abstractthis study presents sensitive high resolution ion microprobe shrimp u pb zircon ages k ar ages and whole rock chemical and isotopic sr nd compositions of the early cretaceous igneous activity in western south korea the volcanics and plutons yield zircon u pb ages of ca 110 ma in the albian of the late early cretaceous k ar biotite and plagioclase ages are slightly younger ca 103 ma the geochemical signatures of the rocks are characterized by negative nb ta and ti anomalies relatively low nd t values between 15 91 and 9 36 and enrichment in light rare earth elements suggesting the effects of subduction related magmatism together with the sr and nd isotopic compositions of the intermediate to acid volcanics geochemical characteristics reflect a lower crustal magma source this albian event over the korean peninsula is related to early jurassic subduction and subsequent lithospheric delamination and or slab rollback after the early cretaceous amalgamation between the north c

tectonics and surface effects of the supercontinent columbia abstract assembly of the supercontinent columbia at about 1 85 1 90 ga coincided with several events that affected the entire earth the oldest worldwide network of orogenic belts formed at the same time although some granite granodiorite gg suites had formed earlier the gg suites became common in the 1 8 1 9 ga orogenic belts these suites succeeded the older tonalite trondhjemite granodiorite ttg suites which were not produced after 1 8 ga changes on the earth s surface at 1 8 1 9 ga include rapid increase in the concentration of oxygen in the atmosphere and oceans and probably the evolution of eukaryotes all of these surface changes occurred as columbia accreted and the assembly of columbia may have contributed to the drastic changes in the earth s surface environment as well as to the evolution of primitive life forms

how do disconnected macropores in sloping soils facilitate preferential flow runoff from hillslopes is generated by processes such as infiltration excess and saturation overland flow subsurface stormflow and subsurface return flow preferential flow through macropores can affect any one of these runoff generation processes field studies at the hitachi ohta experimental watershed in japan have noted that self organization processes may manifest the connectivity of such subsurface flow paths particularly via macropores from hillslopes to stream channels it is well established from soil physics principles that the connectivity of macropore networks depends on soil wetness and this has been shown experimentally at hitachi ohta where subsurface flow and streamflow respond to thresholds of wetness numerical solutions to the three dimensional richards equation are derived for a sloping soil block containing a population of disconnected macropores of various sizes shapes and orientations solutions for the case of steady water flux applied to the surface of the soil block are evaluated to determine the conditions where the disconnected macropores become active in the flow process results show that subsurface flow is directed through the preferential flow network in the saturated portion of the soil but bypasses the macropores in the drier regions the preferential flow network expands as the degree of saturation increases the expanding network of active macropores leads to less resistance to overall flow in the domain and access to increased volumes of the flow domain although the individual macropores are disconnected it is argued that large localized hydraulic gradients can potentially lead to preferred zones of subsurface erosion in addition to the importance of these findings related to stormflow generation in catchments they add support to the concept of self organization of subsurface flow systems in soils copyright 2010 john wiley sons ltd

youngest exposed granitoid pluton on earth cooling and rapid uplift of the pliocene quaternary takidani granodiorite in the japan alps central japan the takidani granodiorite is a pluton 13 x 4 km situated along a major axis of the japan alps that was intruded into late pliocene age 2 4 ma volcanic rocks rb sr k ar and fission track dates on coexisting minerals from the pluton are 1 9 0 8 ma geology and mineral dates for the takidani granodiorite indicate that emplacement and cooling of the pluton occurred from late pliocene to quaternary time making the takidani granodiorite the youngest granitoid pluton exposed on earth9s surface mineral ages give a nearly straight path on a temperature time t t diagram according to the closure temperature of the minerals the linearity of the t t path indicates high thermal input from deeper levels in the early stage and cooling through rapid uplift in the late stage the rapid exposure of the takidani granodiorite resulted from more than 2000 m of quaternary uplift along the major axis of the japan alps

hydrological hotspots in blanket peatlands spatial variation in peat permeability around a natural soil pipe 1 measurements were made of the hydraulic conductivity k of peat around a natural soil pipe in a blanket bog this is the first investigation of decimeter scale variability in both vertical k and horizontal k in blanket peats which were found to be higher than indicated by previous research this information suggests that it may be appropriate to reconsider i the spatial sampling strategies employed to investigate subsurface flow in blanket peatlands and ii how field data are used to parameterize flow models critically there was spatial structure in the heterogeneity with a wedge of high k peat directly above the pipe forming a hydrological conduit between near surface peat and the perennially flowing pipe there was also significantly greater horizontal k parallel to the pipe s orientation compared with horizontal k perpendicular to the pipe determinations of the triaxial anisotropy of k undertaken for the first time in peat soils revealed substantial directional variations in k the k around the pipe peat interface was investigated however sample length dependency of k for peat samples precluded the investigation of a hypothesized low k skin around the pipe

mesozoic episodic magmatism in south korea and its tectonic implication 1 ne trending granitoid batholiths in south korea are part of the huge phanerozoic granitoid belt in east asia the crystallization ages of granitoid plutons show three episodes of mesozoic magmatism in south korea triassic 248 210 ma jurassic 197 158 ma and late cretaceous early tertiary 110 50 ma with a late jurassic early cretaceous 50 m y hiatus the granitoid ages and kinematic analyses of the mesozoic structures in south korea suggest that the middle jurassic 180 170 ma dextral strike slip ductile shear zones formed by the northwest orthogonal subduction of the izanagi plate whereas the cretaceous sinistral faults formed by the northward oblique subduction of the same plate which generally agree with proposed reconstruction of plate motions albeit uncertain around east asia among the models proposed to explain magmatic lull in a continental arc shallow angle subduction associated with high convergence rate and subduction of oceanic plateaus might be the probable cause for the magmatic hiatus in south korea and japan the huge width 500 km of the east asian granitoid belt may be explained by oceanward retreat of subduction zone in the cretaceous in association with change in the movement direction of the subducting plate

post rift geodynamics of the songliao basin ne china origin and significance of t11 coniacian unconformity abstract the t11 unconformity lies between the qingshankou and yaojia formations in the post rifting sequence of the cretaceous songliao basin ne china it is intimately associated with petroleum reservoirs and considered to be a disconformity forming in the tectonic quiet stage we present the interpretations from new seismic surveys and cored sections of the cretaceous continental scientific drilling borehole ccsd sk 1 in order to resolve the nature and origin of t11 unconformity the t11 is often a low angle unconformity with underlying qingshankou formation having been deformed and eroded prior to deposition of the yaojia formation in the post rift evolution of the basin it marks an abrupt change from a deep lake to shallow lake or subaerial environment documented by reddening of the lacustrine mudstone extinction of the ostracod assemblages and a great increase of coarse detrital inputs the sharp change of depositional environment the truncation of gentle folds and the cluster of volcanic and paleoearthquake activities all happened simultaneously immediately before the development of t11 unconformity indicating a significant regional compressional uplift event in the basin the timing of the t11 unconformity formation is within the interval 88 86 2 ma correlations with coeval unconformities in other cretaceous sedimentary basins in eastern asia indicate that this compressional uplift coincided with an episode of global plate reorganization between the eurasian and paleo pacific plates that culminated at 88 87 ma during this short interval the northeast asian margin in eastern china south korea japan and russian far east experienced widespread violent volcanic and granite emplacement activity triggered by compression resulting from rapid and orthogonal slab subduction the post rift basin tectonic inversion occurred during t11 coniacian time thereafter the basin again evolved in an extension regime two subsidence phases in post rift history took place as the direct consequence of coniacian compression peak which defined the distribution of oil sources and reservoirs

anisotropy and depth related heterogeneity of hydraulic conductivity in a bog peat i laboratory measurements anisotropy and heterogeneity of hydraulic conductivity k are suspected of greatly affecting rates and patterns of ground water seepage in peats a new laboratory method termed here the modified cube method was used to measure horizontal and vertical hydraulic conductivity kh and kv of 400 samples of bog peat the new method avoids many of the problems associated with existing field and laboratory methods and is shown to give relatively precise measurements of k in the majority of samples tested kh was much greater than kv indicating that the bog peat was strongly anisotropic log10kh log10kv and log10 kh kv were found to vary significantly with depth although none of the relationships was simple we comment on the scale dependency of our measurements

a field scale natural gradient solute transport experiment in peat at a newfoundland blanket bog a field scale natural gradient solute transport experiment conducted at a newfoundland blanket bog resulted in an asymmetrical plume owing to solute retardation in the dual porosity matrix an order of magnitude decrease in hydraulic conductivity 10 20 m downslope of the spill caused the transport rate to decrease and lateral dispersion to increase most transport occurred near the watertable and the transport rate increased as the watertable rose hydraulic conductivity between a depth of 0 and 0 2 m was 1 6 10 2 m s 1 whereas at a depth of 0 5 m it was 5 6 orders of magnitude lower owing to greater compaction and humification of the peat with depth at a depth of 0 4 0 45 m diffusion may have become the dominant transport mechanism in spite of the retardation process the solute front s rate of movement was relatively high about 2 3 m day 1 owing to a combination of the high watertable during the study and a relatively steep hydraulic gradient of 0 055 rain caused dilution and mixing of solute near the watertable evaporation did not have an appreciable effect on solute concentration which is attributable to the high transport rate

anatomy of garnets in a jurassic granite from the south eastern margin of the north china craton magma sources and tectonic implications abstract the late jurassic jingshan granite located at the south eastern margin of the north china craton contains abundant garnets which can be subdivided into three types based on texture and composition i euhedral garnet in mafic biotite and garnet rich enclave grt i ii coarse grained garnet grt ii in the host granite and iii small euhedral garnet in aplite grt iii in general grt i has higher feo cao and lower mno contents than grt ii grt iii has higher mn but lower ca contents than others grt i has lower mree and hree contents than grt ii grt iii has prominent and distinctly negative eu anomaly as well as higher mree composition compared to the others systematic variations in oxygen isotope compositions are observed among the three garnet types with 18 o values of 4 7 in grt iii some of the grt ii and grt iii display two distinct zonings with cores having similar major and trace element compositions to grt i cathodoluminescence cl images revealed that the zircons from different garnet bearing samples possess fine scale oscillatory zoned magmatic rims with inherited cores in situ zircon u pb dating and trace element analyses show that the dark luminescent magmatic rims all have jurassic concordia ages 160 ma and similar trace element patterns most of the inherited cores also display similar triassic ages of 210 236 ma which is similar to the ages of ultrahigh pressure uhp metamorphic rocks of the dabie sulu orogen 230 ma in addition jurassic concordia ages were also found in a zircon inclusion in grt i implying that the grt i was formed shortly before the main magmatic event the age data suggest that the three different garnet types may be genetically related and modified by cogenetic magmatic events based on the zircon u pb ages from different garnet bearing samples the major element trace element oxygen isotope and zoning textures of the three kinds of garnet we suggest that grt i may be peritectic garnet whereas grt ii and iii are probably the results of magmatic dissolution precipitation processes and re equilibration of garnets with changing magmatic conditions during melting differentiation crystallization and cooling within the granite we conclude from the oxygen isotopic character of the garnets and ages of the zircons that the source rocks for the jingshan granites are from dabie sulu orogen representing the south china craton

shallow horizontal groundwater flow in peatlands is reduced by bacteriogenic gas production 1 we tested the extent to which horizontal hydraulic conductivity kh below the water table in near surface peats is affected by the accumulation of biogenic gas bubbles we found 1 immediately after water table rise the peat is not saturated levels of initial undersaturation were between 1 and 9 percent 2 the production of biogenic gas bubbles below the water table causes large reductions typically more than a factor of two in kh

genesis of the zaozigou gold deposit west qinling orogen china constraints from sulfide trace element and stable isotope geochemistry abstract the west qinling orogen central china is endowed with dozens of world class sediment hosted gold deposits most of which have formed from metamorphic fluids released from paleozoic sedimentary rocks during the triassic collisional orogeny here we present trace element and sulfur isotope data of gold bearing pyrite and arsenopyrite along with oxygen and hydrogen isotopes of ore related sericite to show that the early triassic zaozigou gold deposit 142 t in the xiahe hezuo district may have contrasting origin gold mineralization at zaozigou is dominated by fine grained pyrite and arsenopyrite disseminations py1 and asp1 in hydrothermally altered triassic flysch and less significantly in early triassic granitoid dike swarm the disseminated ores are overprinted by quartz sulfide ankerite sulfide vein veinlets which contain less abundant coarser pyrite and arsenopyrite py2 and asp2 and are less economically significant gold occurs as invisible gold in fine grained arsenian pyrite and arsenopyrite of the disseminated ores with subordinate native gold grains locally observed in the quartz sulfide ankerite vein veinlets the two types of pyrite py1 vs py2 and arsenopyrite asp1 vs asp2 are consistently enriched in as au co ni mn cu zn ag sb w pb te and bi and have well comparable 34s values ranging from 12 0 to 5 5 grain scale variation has been observed for au and other trace elements both in py1 and py2 likely reflecting changes in physio chemical conditions such as fo2 fs2 and temperature due to fluid rock interactions and or fluid mixing the 34s values are broadly consistent with sulfur isotopic compositions of many early triassic ilmenite series intrusions in the xiahe hezuo district and thus suggest a magmatic sulfur derivation from the reduced magmas that have assimilated carbonaceous sedimentary rocks the d and 18o values of ore fluids calculated from isotopic compositions of ore related sericite range from 56 to 76 and 10 1 to 12 4 respectively indicating a magmatic fluids exsolved from the above mentioned ilmenite series magma or a mixture of such as fluid with a metamorphic derived component synthesis of geochronological and geochemical data throughout the xiahe hezuo district led us to conclude that the zaozigou gold deposits can be considered as a shallow seated distal product of a reduced intrusion related gold system

remelting of an andesitic crust as a possible origin for rhyolitic magma in oceanic arcs an example from the izu bonin arc

ecotone or ecocline ecological boundaries in estuaries abstract two main ecological boundaries ecotone and ecocline have been defined in landscape ecology at this scale the estuary represents a boundary between rivers and the sea but there has been no attempt to fit empirical data for estuaries to these boundary models an extensive data set from the thames estuary was analysed using multivariate techniques and species range analysis in order to investigate whether the ecocline or the ecotone model was most relevant to this estuary data for periods of high and low freshwater flow allowed the impact of large scale fluctuations implicit in both models to be determined a continuum of assemblages existed along the salinity gradient from freshwater river to the north sea with shifts in the ranges of organisms apparent in response to changes in freshwater flow this pattern closely fits an ecocline model however the estuary differs from previously defined ecoclines in having two overlapping gradients in the major stressor from river to mid estuary for freshwater species and from sea to mid estuary for marine species we propose therefore that the estuary represents a two ecocline model with fauna inhabiting the mid estuary being either freshwater or marine species at the edge of their range rather than true estuarine organisms this allows a redefinition of the remane diagram with estuarine species removed and supports previous arguments that brackish water species do not exist such two ecocline models may also exist in other marine systems such as rocky shores

zircon u pb ages and hf o isotopes and whole rock sr nd isotopes of the bozhushan granite yunnan province sw china constraints on petrogenesis and tectonic setting abstract the bainiuchang silver polymetallic ore deposit is a super large deposit in the western part of the south china tungsten tin province or the nanling tungsten tin province the deposit is spatially and temporally associated with the bozhushan granite pluton our new data indicate that the bozhushan granitoids formed at 86 87 ma the granitoids are geochemically consistent with a type granite the bozhushan pluton consists predominantly of biotite granite that is characterized by weakly peraluminous to metaluminous compositions and high alkali contents na2o k2o 7 51 9 06 wt the granitic rocks are enriched in large ion lithophile elements lile rb th u and k but relatively depleted in ba and sr in addition they have high zr nb ce y contents 310 478 ppm and high 10 000 ga al ratios 2 7 3 1 the temperatures of the parental magmas for the bozhushan granites are estimated to be 790 842 c based on the zircon saturation thermometer isotopically the bozhushan granites are characterized by elevated initial 87sr 86sr ratios 0 7126 0 7257 and low end values 11 2 to 12 4 and high 18o values 7 91 9 58 and low ehf values 9 5 to 6 1 for zircon crystals which indicate a dominant continental crustal source the two stage hf model ages vary from 1 53 to 1 86 ga the isotopic compositions support the interpretation that the granitic rocks formed by melting of the meso and neoproterozoic metasedimentary basements of the cathaysia block these results together with geological records in the other parts of the western cathaysia block suggest that the formation of the bozhushan a type granites is related to lithospheric extension and asthenospheric upwelling that are associated with the change of plate motion in late cretaceous