a framework for karst ecohydrology ecohydrology can be defined as the science of integrating hydrological and biological processes over varied spatial and temporal scales there exists in karst a strong and direct interaction between the circulation and storage of groundwater and surface water these fluxes in turn affect the spatial distribution of organisms in these habitats because of the fact that the appearance storage and circulation of water in karstified areas is significantly different from other more homogenous and isotropic terrains karst ecohydrology should develop original methods and approaches at the same time traditional approaches are also very useful large karst underground geomorphological patterns occur in many sizes and varieties ranging from a few meters long or deep to very large the deepest being deeper than 1km and longer than hundreds of kilometres in this article special attention is paid to ecohydrological functions of karst underground features caves pits conduits etc which play a crucial dual role in 1 hydrology and hydrogeology of water circulation and storage and 2 ecology of many rare and endangered species differences in morphology hydrology hydrogeology and climate have resulted in a range of different environments which provide the opportunity for the coexistence of different species the role of the epikarst and vadose zones as well as caves in ecohydrological processes is discussed the importance of the flood factor in karst ecology is analysed the aim of this article is to move forward the discussion among different disciplines to promote and develop a conceptual framework for karst ecohydrology

little river revisited thirty five years after hack and goodlett abstract in possibly the first detailed study to relate geomorphology vegetation and hydrology at a watershed scale hack and goodlett 1960 documented variation in the eastern forest with topograhic positions of cove side slope and nose runoff identified as convergent parallel or divergent supported forest types respectively of northern hardwood oak and yellow pine the study conducted in the little river basin of northwestern virginia also described effects on landforms and vegetation of a catastrophic flood that occurred in june 1949 field investigations conducted nearly 4 decades later review selected parts of the study by hack and goodlett 1960 replicate data provide a basis to evaluate interpretations of hack and goodlett to document geomorphic change within the little river basin since the 1949 flood and to identify vegetation change in uplands and bottomlands results suggest that change to hillslope landforms has been minor since 1949 but that changes have occurred to the little river and its tributaries seemingly during flow events of 1952 1955 and 1985 change in areal extent of forest types was not detected change in the relative abundances of dominant species may have resulted from 20th century fire suppression

the role of the subcutaneous zone in karst hydrology abstract the subcutaneous zone is the upper weathered layer of rock beneath the soil but above the permanently saturated phreatic zone it is of particular hydrological importance in karst because of its high secondary permeability arising from the considerable chemical solution in this zone however corrosional enlargement of fissures diminishes with depth thus permeability decreases in the same direction with the result that percolation is inhibited except down widened master joints and faults storage of water consequently occurs in this zone particularly after storms the upper surface of this suspended saturated layer in the subcutaneous zone is defined by a perched water table which slopes towards points of rapid vertical percolation the potential induces lateral water movement converging on the most permeable areas such as beneath dolines leakage from the subcutaneous store sustains slow percolation in the vadose zone cross correlation of rainfall with percolation rates in caves in new mexico u s a and new zealand reveal response lags of 2 14 weeks with no apparent relationship to depth below the surface other percolation sites show no correlation with rainfall interpreted as being a consequence of considerable friction in tight fissure networks the recognition of storage and rapid as well as very slow percolation from the subcutaneous zone requires re interpretation of the components of hydrographs from karst springs and of some conceptual models of karst aquifers the importance of subcutaneous storage in sustaining baseflow discharge at some sites must be recognised as must the contribution of subcutaneous water to flood hydrographs methods of estimating the volumes of subcutaneous and phreatic components of karst spring flood hydrographs are presented the paper concludes with a discussion of the significance of subcutaneous hydrologic processes for an understanding of karst geomorphology the desirability of explaining karst landform evolution in terms of hydrologic processes is stressed

the water on a small karst island the island of korcula croatia as an example the island of korcula which has an area of 271 47 km2 is located along the north eastern coast of the adriatic sea due to the mediterranean climate size and karst geology its water resources are very scarce this paper describes the natural features of the island air temperature precipitation geology hydrogeology and groundwater which are important for the water appearance and its distribution in time and space the water supply of the island has been managed in the following ways through a pipeline from the mainland by drawing groundwater and by rain harvesting tourism causes high seasonal water needs which are barely met by the existing water supply system therefore present water resource management on the island must be improved the paper also presents mathematical programming scheme to get optimal costs and benefits of water exploitation on the island besides economic aspect linear programming is applied to social and ecological objectives as well this study suggests that island s water management should be primarily based on wisely using its proper water resources

impact of intensive groundwater exploitation on an unprotected covered karst aquifer a case study in kermanshah province western iran islam abad region located in the southwestern of kermanshah province is a karst region where over exploitation from the deep karst water resources has directly affected the water balance of the whole area using a combination of geophysical investigations and analysis of well log data and other relevant hydrogeological studies we looked for the actual relationship between over exploitation from deep water wells penetrated into the covered karst aquifer and the drying out of some of the main karst springs throughout the study area in total 20 piezometric wells and 4 main karst springs have been chosen for groundwater monitoring network by integrating gis processing system and a classical water balance method together with hydrogeology and hydrogeochemical spatial maps critical zones of human impacts on groundwater resources made by water extraction for agricultural demand were identified results show that water balance in the islam abad basin is in clear disequilibrium since 2 15 mcm of water depletes from the main aquifers of the study area annually this volume of water shortage has resulted in a 7 m groundwater level decline in the last decade which caused both drying out and reduction in discharge rate of some of the main karst springs throughout the study area depths of penetration of deep water wells into the covered karst aquifer vary from 1 to 93 m hydrogeochemical evaluations including ion relations and hydrogeochemical diagrams show interactions between karst and alluvium aquifers results showed a broad connection between these two resources and therefore any pressure on alluvium aquifer will affect the karst aquifer especially by excessive deep water wells drilling in mutual alluvial and covered karst aquifers

hydraulic properties of karst fractures filled with soils and regolith materials implication for their ecohydrological functions abstract in regions with shallow soils underlain by fractured bedrock hydrological processes of substrate are no longer only limited to soil layers however ecohydrological functions of bedrock fractures especially those filled with different soil and regolith materials have not been fully understood in this study we aimed to evaluate water transport and supplying capacities of the filled fractures through investigating hydraulic properties and explore their dominant influencing factors three typical fractures a vertical one filled with fine textured soil vsf a vertical one filled with soil and regolith materials vsrf and a non vertical one filled with coarse textured soil nsf were selected from a large newly excavated trench on a karst hillslope of southwest china stratified samples of fracture fillings were collected to measure saturated hydraulic conductivity k s water retention curves and basic physicochemical properties additionally twenty soil profiles in different topographic locations in the same study area were also analyzed in order to support the results derived from the filled fractures all fractures exhibited extremely high k s 87 149 mm h 1 in surface soil 0 10 cm which allowed rapid infiltration of rainwater into subsurface subsurface water transport was smooth when underlying fracture fillings were loamy with relatively high k s about 10 mm h 1 like in nsf but was blocked when they were clayey with low k s 1 like in vsf and vsrf all fracture fillings had abilities to hold water and available water was the most in nsf which provided an extra water source for plant growth in shallow soil regions the ecohydrological functions of the filled fractures often depend on the properties and layering of fracture fillings which was supported by those obtained from the twenty soil profiles these results are helpful for better understanding of the ecohydrological processes and functions of fractures filled with different materials in karst regions

dissolved oxygen fluctuations in karst spring flow and implications for endemic species barton springs edwards aquifer texas usa summary karst aquifers and springs provide the dissolved oxygen critical for survival of endemic stygophiles worldwide but little is known about fluctuations of dissolved oxygen concentrations do and factors that control those concentrations we investigated temporal variation in do at barton springs austin texas usa during 2006 2012 do fluctuated by as much as a factor of 2 and at some periods decreased to concentrations that adversely affect the barton springs salamander eurycea sorosum 4 4 mg l a federally listed endangered species endemic to barton springs do was lowest 4 4 mg l when discharge was low 1 m 3 s and spring water temperature was 21 c although not at a maximum the minimum do recorded was 4 0 mg l relatively low do 3 s and maximum t 22 2 c a four segment linear regression model with daily data for discharge and spring water temperature as explanatory variables provided an excellent fit for mean daily do nash sutcliffe coefficient for the validation period of 0 90 do also fluctuated at short term timescales in response to storms and do measured at 15 min intervals could be simulated with a combination of discharge spring temperature and specific conductance as explanatory variables on the basis of the daily data regression model we hypothesize that more frequent low do corresponding to salamander mortality could result from i lower discharge from barton springs resulting from increased groundwater withdrawals or decreased recharge as a result of climate change and or ii higher groundwater temperature as a result of climate change

characterization of the main karst aquifers of the tezbent plateau tebessa region northeast of algeria based on hydrogeochemical and isotopic data chemical properties and hydrogeological characterization of water resources were studied in the hammemt plain which is located in the northwest of the tezbent mountain range city of tebessa northeast of algeria which drains carbonate aquifers through various large karst springs the physical and chemical characteristics of spring and well water samples were studied for 2 years in order to assess the origin of groundwater and determine the factors driving its geochemical composition the ionic speciation and mineral dissolution precipitation were calculated where we found that water wells characterizing groundwater circulation at shallow depths are moderate to highly mineralized waters of the na hco3 type in contrast to the shallow environment the co2 rich deeper waters are of the ca hco3 type and undergo significant changes in their baseline chemistry along flow lines with increasing residence time the main factors controlling the groundwater composition and its seasonal variations are geology because of the presence of different carbonate formations additionally elevation and the rate of karst development supersaturation with respect to calcite indicates co2 degasing occurs either inside the aquifer in open conduits or at the outlet in reservoirs undersaturation with respect to calcite shows the existence of fast flow and short residence time conditions inside the aquifer the main springs and wells of the tazbent mountain have been studied by means of stable isotope measurement where the values are varied in 18o between 8 2 and 7 76 for spring samples and from 8 26 to 7 15 for well samples and in 2h between 52 92 and 49 11 for spring samples and from 55 47 to 47 44 for well samples showing that the groundwater recharge is of meteoric origin and suggests the absence of the evaporation effect on the isotopic composition

effects of juniper removal and rainfall variation on tree transpiration in a semi arid karst evidence of complex water storage dynamics brush removal is widely practiced as a tool for increasing groundwater recharge but its efficacy depends greatly on the way in which the removed species interact with the hydrological system relative to the vegetation replacing it we examined the effects of ashe juniper removal in the recharge zone of the edwards aquifer texas usa a karst aquifer the study was conducted in an ashe juniper juniperus ashei live oak quercus fusiformis woodland on a hill slope composed of rocky shallow soils over fractured limestone bedrock ashe juniper is a native species that has been encroaching grasslands and savannas over the past century in september 2008 a plot was cleared of 90 of its juniper trees tree transpiration predawn water potentials and vegetation cover across the cleared plot and an adjacent reference site were measured from may 2009 to december 2011 stand level tree transpiration from may 2009 to march 2010 was diminished by a severe summer drought in 2009 from which trees were slow to recover subsequently tree transpiration was 5 10 higher in the woodland compared to the clearing for all of 2011 also a drought year tree transpiration in the woodland exceeded precipitation inputs indicating a high capacity for water storage at the study site however site differences for oak trees were generally larger than for juniper trees while juniper removal accounted for a 431 mm year 1 difference in tree transpiration between sites vegetation cover in the clearing increased from 42 to 90 over two years suggesting that understory growth was increasingly compensating for the loss of juniper transpiration we conclude that the removal of a relatively shallow rooted tree when replaced with herbaceous vegetation and low shrubs has little effect on deep recharge by contrast successive years of precipitation extremes may be more effective increasing recharge by lowering the water transport capacity of trees in the aftermath of severe drought copyright 2016 john wiley sons ltd

paleomagnetic constraints on the extent of the stable body of the south china block since the cretaceous new data from the yuanma basin china abstract we undertook a paleomagnetic investigation of cretaceous red sandstones at 30 sites within the yuanma basin in western hunan central south china block scb china the aim of this study is to further constrain the extent of the scb that has been stable since the cretaceous we isolated the characteristic directions of higher temperature components htcs with an unblocking temperature of 650 to 690 c by progressive thermal demagnetization and principal component analysis the optimal concentrations of global mean htc directions calculated using the direction correction tilt test were achieved at 92 7 59 1 87 9 25 0 and 93 3 19 7 untilting indistinguishable from 100 untilting for early cretaceous k1 13 sites late cretaceous k2 17 sites and k site groupings k1 k2 30 sites respectively this treatment yielded positive tilt tests and the htcs are considered to be primary magnetic components acquired before tilting of the sedimentary layers early k1 and late k2 cretaceous paleomagnetic poles calculated using the site mean directions untilted completely are located at similar positions this suggests the absence of local rotations linked to cretaceous strain within the study area the cretaceous k1 k2 mean paleomagnetic pole calculated using virtual geomagnetic poles from all sites is in agreement with previously reported cretaceous paleomagnetic poles from the eastern and western scb this indicates that the hunan region has been part of the stable body of the scb since the cretaceous and that the tectonic influence of the india asia collision did not extend to within the stable body of the scb the reference cretaceous pole position latitude 80 1 n longitude 204 1 e a 95 2 5 calculated using eight cretaceous poles from the stable body of the scb is similar to those determined from stable eurasia and the north china block ncb this result indicates that the india asia collision caused no relative motion as detected by paleomagnetic analysis among stable eurasia ncb and the stable body of the scb

water geochemical characteristic variations in and around a karst dominated natural reserve area southwestern china this paper reports original data on the physical and chemical parameters of precipitation river water and groundwater in and around the longhushan nature reserve area located in southwestern china karst region and provides a preliminary characterization of the hydrogeochemical process governing the natural water evolution in this area the rainfall and river water mainly pertain to the hco3 ca2 type and groundwater mainly pertain to the hco3 ca2 mg2 type the hco3 was the predominant anion and ca2 was the predominant cation in all waters respectively the gibbs boomerang envelop model the 1 1 relationship of na plus k versus cl as well as the 1 1 relationship of ca2 plus mg2 versus hco3 all suggested geochemical weathering is the main controlling factor for the geochemical compositions of this natural water in surface water the mg2 ca2 ratios ranged from 0 32 to 0 42 and the na ca2 varied between 0 04 and 0 05 in the groundwater the mg2 ca2 ratios varied from 0 37 to 0 62 and were below the ideal ratio of 0 8 these ratios showed the presence of a dolomite source analysis of trace elements showed that as b pb se sr v and zn elements were abundant in the natural water during summer in this region

structural and stratigraphic development of the newark extensional basin eastern north america evidence for the growth of the basin and its bounding structures the newark basin is a half graben bounded on its northwestern margin by a system of mostly normal slip faults many of which are reactivated paleozoic thrust faults and were active at least sporadically during the deposition of the entire basin fill as a result of along strike variations in displacement on the border fault system subsidence increased from the lateral edges toward the center of the basin and from the hinged margin toward the border fault system some intrabasinal faults also formed during the deposition of units currently preserved in their hanging walls along strike variations in the density of intrabasinal faults probably reflect changes in the dip angle of the border fault system variations in the amount of extension accommodated on these intrabasinal faults resulted in the formation of a transfer fault along strike variations in fault displacement probably produced the transverse folds in the hanging walls immediately adjacent to border faults and major intrabasinal normal faults some folds formed syndepositionally progressively younger strata onlap basement rocks along the hinged margin of the basin and younger splays of the border fault system propagated into the footwall the basin therefore grew deeper wider and longer through time

non linearities in drip water hydrology an example from stump cross caverns yorkshire drip rate data have been collected at 15 min intervals at six locations in stump cross caverns n england since 1998 the different drip sites cover a wide range of drip rates from 2 drips s to 2 drips h and in general the variability of drip rate increases with mean drip rate in our continuous data sampling we observe rapid discharge increases which appear to be synchronous between drips sites and which can be explained by flow switching of the water overlying the cave during times of high infiltration rate such as intense rain storms or rapid snowmelt a test for non linearity white test in the drip series provides very strong evidence that many of the drip sequences are non linear we conclude that at our drip sites there is a non linear input weather and non linearities within the karst system leading to non linear dripping which is independent of drip rate our results have implications for stalagmite palaeoclimatology where such widespread non linearities have not been taken account of

effects of partial and full pipe flow on hydrochemographs of logsdon river mammoth cave kentucky usa summary logsdon river within kentucky s mammoth cave system drains the 25 km2 cave city groundwater basin temperature specific conductance stage and velocity were measured at the river s downstream end within the cave with 2 min resolution for one year beginning on may 5 1995 new interpretation of these data show relationships to the conduit s geometry and fluid transport behavior the 37 observed storm hydrographs chemographs are classified into two groups open channel flow and pipe flow conduit filled in the 16 pipe flow events logsdon river exceeded the capacity of its conduit raising the water table above the conduit ceiling with some storm water thus temporarily stored within the aquifer adjacent to the conduit pipe flow events were characterized by depression of specific conductance spc before peak discharge a peak in spc at peak discharge and a second depression in spc after peak discharge the first spc minimum represents the maximum concentration of passing storm water and the second is interpreted as the result of recent storm water draining back into the conduit having been temporarily stored in the aquifer adjacent to the conduit mean velocity decreases in the transition from partial to full pipe flow due to increased head loss at full pipe flow compared to nearly full pipe flow each of the open channel flow cases shows a depression in spc either coincident with or after peak discharge while the hydrochemographs of pipe flow are mainly controlled by the aquifer conduit network geometry in open channel cases they are mainly controlled by external recharge conditions including behavior of sinking streams

karst geomorphology of carbonatic conglomerates in the folded molasse zone of the northern alps austria germany abstract the folded molasse zone of the northern alps consists of clastic sedimentary rocks that are usually not considered to be karstifiable however large areas within this zone are composed of carbonatic conglomerates numerous karst landforms have recently been discovered but are not recorded on official maps and in the literature therefore a research programme was initiated at the hochgrat site austria germany that included geomorphological mapping and characterisation of the karst phenomena both fracture controlled and hydrodynamically controlled karren were observed on conglomerate outcrops the predominant karst landforms dolines are typically circular funnel shaped most often 2 to 9 m in diameter 1 to 6 m deep and frequently act as swallow holes poljes that are atypically small 1 ha occur in either glacial cirques or syncline depressions are flat floored and lined with sediment and soil and drain underground via swallow holes short caves springs with marked discharge variations and estavelles are further evidence for karst development karstic landforms are widespread in carbonatic conglomerate terrains but their dimensions are smaller than in typical limestone karst the practical implications of these findings are also briefly mentioned in this paper

hydrology of cave drip waters at varying bedrock depths from a karst system in southeastern australia the study of how cave drip water discharge responds to recharge events is fundamental to evaluating the potential of actively forming speleothems as high resolution climate archives most previous research has focused on caves of the northern hemisphere middle latitudes where recharge is strongly seasonal few studies have explored drip water behaviour from regions where the expected seasonal rainfall pattern is significantly perturbed on an irregular basis by changing regional atmospheric circulation patterns here we report the results of a 4 year study of cave drip water climate relationships from two caves in eastern australia the discharge of 10 drip sites located beneath bedrock thicknesses of 12 22 and 45 m was monitored either continuously using automated infrared sensors or at discrete approximately monthly intervals and compared with local rainfall and water balance data the study period traversed two major droughts including the severe 2002 2003 el nino drips at 12 and 22 m depths responded almost simultaneously to individual recharge events although the time lag between individual events varied according to the volume of recharge and pre event storage overall a steady decline in discharge is evident through the moisture deficit period with increased flows through phases of positive water balance speleothems growing at these and similar shallow chamber sites have potential for reconstructing palaeo rainfall trends at high resolution although the highly variable nature of year to year recharge would make it difficult to obtain data on a calendrical time scale drips at 45 m depth did not respond consistently to individual recharge events and displayed hydrological behaviour markedly dissimilar to one another and to the near surface drip sites indicating great complexity in karst architecture and the absence of fissure flow although speleothems at this depth may well preserve information on longer term rainfall trends their potential to encode a palaeo rainfall variability signal at interannual resolution is poor copyright 2007 john wiley sons ltd

evolution of carbonate and karst critical zones abstract carbonate terrains ct underlie one fifth of terrestrial ice free land and are an important supply of potable water to the world s population and yet processes endemic to ct critical zones cz and responses of these processes to climatic and anthropogenic pressures are not well understood given the rapid dissolution rates and ability to generate well developed networks of secondary porosity these landscapes can be highly sensitive to impacts from climate change e g modifications of temperature precipitation sea level and human disturbance e g water withdrawal diversions changes in land use land cover this special issue includes 16 papers focused on ct cz processes and potential responses to climatic and human perturbations five major themes emerge from these papers namely 1 anthropogenic climate and land use changes alter ct cz weathering rate and diagenesis 2 metal and carbon fluxes in ct cz will respond to increasing hydrologic variance caused by climate change 3 endogenous and exogenous processes operating over short time periods

submerged caves of croatia distribution classification and origin presently 235 submerged caves and pits have been recorded along the croatian coast and islands partly or completely submerged by sea water contrary to the inland situation recorded submerged features are predominantly horizontal 60 though there are indications that the real situation is similar to that of the continental part where 69 are vertical pits completely marine conditions are established in 126 caves and the rest are anchihaline caves and submarine springs speleothems are found in more than 140 caves by their origin the investigated caves are all continental features formed in mesozoic and palaeogene carbonates subsequently submerged owing to sea transgression due to the relatively low wave energy rapid sea level rise and maturity of the host rock they do not fit into concepts of a sea cave or a flank margin cave development but they fulfil several conditions for being the blue holes since the term blue hole is mainly associated with the bahamian karst our attempt is only to show the possible similarities with no intention of ascribing that term to the croatian caves beside karstological issues croatian submerged caves are unique environmental archaeological and tourism assets

uranium metallogenesis of the peraluminous leucogranite from the pontivy rostrenen magmatic complex french armorican variscan belt the result of long term oxidized hydrothermal alteration during strike slip deformation in the french armorican variscan belt most of the economically significant hydrothermal u deposits are spatially associated with peraluminous leucogranites emplaced along the south armorican shear zone sasz a dextral lithospheric scale wrench fault that recorded ductile deformation from ca 315 to 300 ma in the pontivy rostrenen complex a composite intrusion the u mineralization is spatially associated with brittle structures related to deformation along the sasz in contrast to monzogranite and quartz monzodiorite 3 3 the leucogranite samples are characterized by highly variable u contents 3 to 27 ppm and th u ratios 0 1 to 5 suggesting that the crystallization of magmatic uranium oxide in the more evolved facies was followed by uranium oxide leaching during hydrothermal alteration and or surface weathering u pb dating of uranium oxides from the deposits reveals that they mostly formed between ca 300 and 270 ma in monzogranite and quartz monzodiorite apatite grains display magmatic textures and provide u pb ages of ca 315 ma reflecting the time of emplacement of the intrusions in contrast apatite grains from the leucogranite display textural geochemical and geochronological evidences for interaction with u rich oxidized hydrothermal fluids contemporaneously with u mineralizing events from 300 to 270 ma infiltration of surface derived oxidized fluids leached magmatic uranium oxide from fertile leucogranite and formed u deposits this phenomenon was sustained by brittle deformation and by the persistence of thermal anomalies associated with u rich granitic bodies

epikarst communities biodiversity hotspots and potential water tracers there is an exceptionally rich aquatic fauna in the epikarst the skin of karst high species richness in the epikarst coupled with its special vulnerability as the first point of entry of nearly all toxic spills makes its protection especially important the epikarst fauna may also be an useful tool in tracing the potential route of pollutants copepods in epikarst have extremely local distributions and their body size is such that they are largely at the mercy of directional flows in a series of caves in southwest slovenia and west virginia a significant fraction of the copepod species occur in less than 100 m of linear extent this suggests a pattern of highly restricted lateral flow under normal conditions and the distribution of copepods could potentially be used to trace water movement under high flow conditions as would often be the case with toxic spill mounding of water may increase the lateral radius of flow nevertheless copepods may be useful tracers

impact of grout curtains on karst groundwater behaviour an example from the dinaric karst grout curtains are vertical grout walls installed in the ground in karst terrains their construction is primarily connected with dams and reservoirs their main role is to increase watertightness and prevent progressive erosion blocking possible seepage paths along karst fissures and conduits in this paper changes in the behaviour of the groundwater level gwl and the water temperature in nine deep piezometers which were caused by the construction of a grout curtain at the ale reservoir on the cetina river croatia were analysed the total length of the grout curtain is 3 966 m it spreads 120 m below the dam the most of analysed data is from the period after the dam had been built only few data and figures concern the comparison between pre and post dam periods the hourly data of the gwl and the water temperature were analysed for the period between 1 sep 2008 at 02 h to 31 dec 2009 at 23 h 11 687 hours total in six deep piezometers marked in the text and figures as 1 2 3 4 5 and 6 for three piezometers marked in the text and figures as a b and c some discontinuous measurements of the gwl and the water temperature were available for analysis the construction of the grout curtain made strong sudden and possibly dangerous changes to the characteristics of the aquifer and the circulation of groundwater in the local area special attention is paid to analyses of the behaviour of the hourly gwl data measured in the piezometers pairs two neighbouring piezometers one inside and the other outside of the grout curtain during more than 80 of the analysed period the gwl was higher in the piezometer inside the grout curtain than the one outside of it the intensity and range of the dynamics of gwl was higher in piezometer outside the grout curtain than the inside ones after the construction of the grout curtain the maximum measured hydrostatic pressure on some parts of the grout curtain was about 40 m it changes quickly in both time and direction the water temperature was found to be similar in all of the measured piezometers and it varies between 10 2 and 15 7 oc with an average value of 12 7 oc

cretaceous paleomagnetism of the eastern south china block establishment of the stable body of scb abstract a paleomagnetic investigation was performed on the cretaceous red sandstones collected at the eastern side of the south china block scb china and attempted to establish the stable part of the scb since the cretaceous paleomagnetic specimens were collected at 39 25 and 14 sites from three independent parts the northern central and southern regions of eastern scb respectively characteristic directions of higher temperature components htcs with an unblocking temperature of 680 c were isolated from 69 78 sites the optimal concentrations of global mean htc directions calculated using the direction correction tilt test were achieved at 79 19 95 27 71 37 and 117 98 untilting for the early cretaceous sites from the northern part late cretaceous sites from the northern central and southern parts respectively this treatment gives positive tilt tests or brings the optimal concentration not far from being indistinguishable from positive tilt tests although this observation can be due to imperfect separation of a primary component htc from a secondary one lower temperature component we adopted completely 100 untilted directions of the htcs as the paleomagnetic field directions during the cretaceous because the mean directions after complete untilting were almost equal to each mean direction after incomplete untilting showing the optimal concentration the mean paleomagnetic poles for three independent parts were located at almost the same positions and were indistinguishable from that for sichuan the western side of scb at the 95 confidence level this observation indicates that there is no relative movement between the eastern and western sides of scb and implies that a large part of the scb excluding a 400 km wide swath along the red river fault has behaved as its coherent stable body since the cretaceous the cretaceous paleomagnetic pole for the stable body of the scb latitude 80 0 n longitude 206 7 e a 95 2 5 is worth using as a reference cretaceous paleomagnetic pole of the scb and agrees strongly with the reference eurasian paleomagnetic pole during the cretaceous period