bed material transport estimated from the virtual velocity of sediment this study evaluates the possibility of determining bed material transport using the virtual rate of travel of individual particles dimensions of the active layer of the streambed and porosity and density of streambed material magnetically tagged stones and scour indicators were employed in carnation creek british columbia to quantify transport rates observations cover flows up to 36 m3 s 1 0 081 transport rates ranging from 0 090 to 9 7 kg s 1 0 12 13 2 m3 h 1 display a relatively sensitive trend with maximum stream power as expected error analysis indicates that uncertainty in virtual velocity covers the majority of sample variance an evaluation of the two measurement techniques used to delineate active layer dimensions magnetically tagged stones and scour indicators indicates that they yield comparable depths widths and transport rates over the range of flows observed issues for further study are discussed 1998 john wiley sons ltd

strontium and carbon isotope constraints on carbonate solution interactions and inter aquifer mixing in groundwaters of the semi arid murray basin australia abstract strontium and carbon isotopes are used to study the effect of carbonate mineral dissolution and inter aquifer mixing on the chemical evolution of groundwater from the murray group limestone aquifer in semi arid se australia the 87 sr 86 sr ratio of groundwater evolves from 0 7097 at the basin margin to a less radiogenic value of 0 7084 about 250 km down gradient which is similar to the 87 sr 86 sr ratio of the aquifer carbonate matrix the concomitant increase in 13 c dic sr ca and mg ca ratios in the groundwater along a 250 km transect suggests that incongruent dissolution of high mg calcite controls the carbonate geochemistry in this aquifer further down gradient the groundwater is characterized by a relatively more radiogenic 87 sr 86 sr ratio caused by upward leakage and mixing with more radiogenic groundwater from the renmark group sand aquifer a mixing model using 87 sr 86 sr ratio suggests that the fraction of water that contribute to the murray group aquifer through upward leakage from underlying renmark group aquifer ranges from 15 to 85

the behavior of lithium and its isotopes in oilfield brines evidence from the heletz kokhav field israel twenty four brine samples from the heletz kokhav oilfield israel have been analyzed for chemical composition and li isotope ratios the chemical composition of the brines together with geological evidence suggests derivation from messinian seawater by evaporation that proceeded well into the gypsum stability field but failed to reach the stage of halite crystallization the present salinity of the samples 18 47 g cl l was achieved by dilution of the original evaporitic brine by local fresh waters like brines from other sedimentary basins the li cl ratios in the heletz kokhav samples show a prominent li enrichment five fold to eight fold relative to modern seawater the isotopic ratios of li expressed in the 6 li notation vary from 26 3 to 17 9 all values being significantly higher than that of modern seawater 32 irrespective of their corresponding li concentration 1 0 2 3 mg l the isotopic composition of li and the li cl ratio in the oilfield brines were acquired in two stages a the original evaporated seawater gained isotopically light li during the diagenetic interaction between the interstitial messinian brine and the basin sediments a parent brine with an elevated li cl ratio was formed the brine was later diluted in the oilfields b the 6 li values of the final brines were determined during epigenetic interaction with the heletz kokhav aquifer rocks at the same time the li cl ratio inherited from stage a remained largely unchanged this work represents the first use of lithium isotopic composition to elucidate the origin and evolution of formation waters in sedimentary basins copyright 2002 elsevier science ltd

formal subdivision of the quaternary system period past present and future abstract the quaternary system period represents the past 2 58 million years and is officially subdivided into the pleistocene and holocene series epochs with the base of the holocene assigned an age of 11 700 calendar years before ad 2000 the two lowest stages of the pleistocene the gelasian base 2 58 ma and the calabrian base 1 80 ma have been ratified and these effectively constitute the lower pleistocene subseries all other official subdivisions are pending for the middle pleistocene subseries three candidate global boundary stratotype sections and points gssps are under consideration the valle di manche in calabria and montalbano jonico in basilicata both in southern italy and the chiba section in japan the matuyama brunhes chron boundary 773 ka serves as the principal guide for the base of the middle pleistocene the base of the upper pleistocene subseries is generally agreed to coincide approximately with that of the last interglacial marine isotope substage 5e 130 ka the fronte section near taranto in southern italy represents a possible candidate gssp but an antarctic ice core might also serve this purpose a tripartite subdivision of the holocene with subseries stage boundaries at 8200 and 4200 years b p is also under consideration additional fine scale formal subdivision of the quaternary is being explored with the last glacial maximum serving as a test case the anthropocene is both an informal and undefined interval of time that includes the present day its duration formal informal status rank and method of definition are all under debate with one suggestion that it be defined as a formal unit beginning with the world s first nuclear bomb explosion on july 16th 1945 suggested and proposed gssps are compared and critiqued the history leading to ratification of the quaternary period in 2009 is examined drawing upon published and unpublished material

secular variation in seawater chemistry during the phanerozoic as indicated by brine inclusions in halite analysis of data on the chemical composition of primary fluid inclusions brine inclusions in primary bedded halite from many evaporite formations of northern pangea shows that during the phanerozoic the chemical composition of marine brines was oscillating significantly between the na k mg ca cl type and the na k mg cl so4 type we regard those changes as corresponding to the chemical evolution of the phanerozoic ocean the changes correlate in time with earlier suggested secular changes in the mineralogies of marine nonskeletal limestones and potash evaporites in addition to those secular changes of seawater chemistry the concentrations of k mg ca and so4 ions in marine brines underwent important changes under the influence of local factors including rock water interaction these secondary changes did not influence the principal chemical type of the brine characteristic for a given time interval in the past concentration of the ca ion did not exceed the present concentration in marine water by a

a multi isotope b sr o h and c and age dating 3h 3he and 14c study of groundwater from salinas valley california hydrochemistry dynamics and contamination processes 1 the chemical and isotope 11b 10b 87sr 86sr 18o 16o 2h h 13c 12c 14c and 3he 3h compositions of groundwater from the upper aquifer system of the salinas valley in coastal central california were investigated in order to delineate the origin and processes of groundwater contamination in this complex system the salinas valley has a relatively deep confined 400 foot aquifer overlain by a 180 foot aquifer and a shallower perched aquifer all made up of alluvial sand gravel and clay deposits groundwater from the aquifers have different 14c ages fossil 14c 21 3 percent modern carbon pmc for the 400 foot aquifer and modern 14c 72 2 98 2 pmc for the 180 foot aquifer fresh groundwater in all aquifers is recharged naturally and artificially through the salinas river the two modes of recharge can be distinguished chemically we identified several different saline components with distinguishable chemical and isotopic fingerprints 1 saltwater intrusion in the northern basin has c1 concentrations up to 1700 mg l a na cl ratio less than seawater a marine br cl ratio a ca cl ratio greater than seawater 11b between 17 and 38 and 87sr 86sr between 0 7088 and 0 7096 excess dissolved ca relative to the expected concentration for simple dilution of seawater correlates with 87sr 86sr ratios suggesting base exchange reaction with clay materials 2 agriculture return flow is high in no3 and so4 with a 87sr 86sr 0 7082 11b 19 and 13c between 23 and 17 the 3h 3he ages 5 17 years and 14c data suggest vertical infiltration rates of irrigation water of 3 10 m yr 3 nonmarine saline water in the southern part of the valley has high total dissolved solids up to 3800 mg l high so4 na cl ratio 1 11b between 24 and 30 and 87sr 86sr 0 70852 this groundwater may have acquired its geochemical signature from leaching of sedimentary rocks associated with the coast range marine deposits of mesozoic to early cenozoic age the combination of different geochemical and isotopic fingerprints enables us to delineate the impact of salt sources in different areas of the valley and to reconstruct the origin of the so4 enriched no3 depleted saline plume that is located west of the city of salinas we suggest that the latter is derived from a mixture of different natural saline waters rather than from anthropogenic contamination

geochemical and boron strontium and oxygen isotopic constraints on the origin of the salinity in groundwater from the mediterranean coast of israel in order to identify the origin of the salinity and formation of saline plumes in the central part of the mediterranean coastal aquifer of israel we determined the elemental and boron strontium and oxygen isotopic compositions of fresh and brackish groundwater cl up to 1500 mg l we distinguish between two key anthropogenic sources 1 sewage effluents used for irrigation with high na cl so4 cl and b c1 ratios and low br cl ratios relative to seawater ratios low 11b values 0 10 and high 18o values 4 and 2 imported water from the sea of galilee that is artificially recharged to the aquifer with high br cl 3 10 3 and 18o values 1 and a low 87sr 86sr ratio of 0 70753 the brackish groundwater from the saline plumes have relatively low na cl ratios 0 5 0 8 and high ca mg mg cl and ca so4 hco3 1 ratios relative to seawater ratios marine so4 cl and br cl ratios 11b values of 24 8 49 9 18o of 2 95 to 4 73 and 87sr 86sr ratios of 0 708275 0 708532 the composition of most of the investigated groundwater from the saline plumes differs from those of the anthropogenic sources imported water fresh uncontaminated groundwater 87sr 86sr of 0 70866 11b of 20 30 and saline water from the adjacent eocene aquitard only in areas of artificial recharge does local groundwater have high br cl and 18o values that are typical to the sea of galilee the linear relationships between chloride and most of the ions including b and sr the relatively high 11b 30 and low 18 o 4 values and the chemical signature of the saline plumes e g marine br cl and so4 cl ratios suggest that 1 mixing processes control the chemical composition of the brackish water within the aquifer and 2 the saline postulated end member has a chemical composition that resembles modified seawater with a marine and higher 11b values and a 87sr 86sr ratio of 0 7083 we propose that most of the salinization phenomena and the formation of saline plumes in the inner parts of the coastal aquifer are derived from upconing of underlying natural saline water bodies and enhanced by overexploitation and draw down of the overlying fresh groundwater

stable isotope mapping in messinian evaporative carbonates of central sicily mapping stable isotope isolines in both modern and ancient evaporative carbonate formations demonstrates that regional variations of 18 o values exist in the case of the messinian central sicilian basin an ancient evaporite basin the distribution pattern of the 18 o isolines can be related to the paleogeometry and paleohydrology of the basin isolines of equal 13 c values also show large regional variations possibly reflecting the domination of different bacterial processes oxidation sulfate reduction or methanogenesis in different regions the potential application for stable isotope mapping in evaporative carbonate formations deposited in both marine and lacustrine environments lies in its ability to predict the location of depositional centers in ancient evaporite basins

manual of neogene foraminifera from off shore nile delta egypt and their biostratigraphic significance abstract the mediterranean nile delta is a major target for hydrocarbon reservoirs in the search for hydrocarbons high resolution biostratigraphy has long been established as high impact and low cost solution to face the challenges in the move towards structurally more complex and unexplored areas to date the biozonation of the nile delta is largely provided by benthic and planktonic index foraminifera we have examined the foraminifera assemblages from ndob 1 a borehole in the northern part of the nile delta the material recovered provides unique and exceptionally well preserved microfossil biotas that completely cover the neogene succession middle miocene to pleistocene this allows the establishment of an intact biozonation scheme for the nile delta region with reliable chronostratigraphic correlation and suitable industrial applications the stratigraphic succession of the nile delta region consists of seven formations sidi salim formation qawasim formation rosetta formations abu madi formation kafr el sheikh formation el wastani formation and mit ghamr formation examination of the planktonic foraminifera assemblages of the ndob 1 borehole from the deep part of the nile delta lead to the identification of twelve biozones globorotalia inflata interval zone globorotalia aemiliana interval zone globorotalia puncticulata interval zone globorotalia puncticulata globorotalia margaritae concurrent range zone globorotalia margaritae interval zone sphaeroidinellopsis seminulina acme zone non distinctive zone globorotalia suterae interval zone globigerina woodi interval zone globorotalia mayeri interval zone globorotalia fohsi peripheroronda interval zone and praeorbulina glomerosa interval zone the biozones fully cover the time span from the middle miocene to the pleistocene the benthic foraminifera recovered allow the identification of five benthic biozones for the pliocene and pleistocene hyalinea balthica interval zone bulimina marginata interval zone bulimina aculeata interval zone gyroidinoides laevigata interval zone and uvigerina rutila interval zone the identified planktonic bioevents were used to calibrate the studied neogene section with the astronomically tuned neogene time scale atnts 2012

a strontium oxygen and hydrogen isotopic composition of brines michigan and appalachian basins ontario and michigan abstract 87 sr 86 sr ratios of brine from samples from the michigan and appalachian basins in ontario and michigan covering the stratigraphic interval from the cambrian to mississippian vary from 0 708 to 0 711 with the exception of the salt units of the salina formation silurian most values are greater than seawater for the time in question indicating water rock interaction the sources of the radiogenic sr has not been identified all samples plot below the gmwl in 18 o 2 h space with the cambrian and ordovician samples closest to the line mixing of brines meteoric and glacial pleistocene water is indicated in some cases the more concentrated brines from each stratigraphic unit show a very narrow spread in values all the ordovician brines show a narrow range over a 200 km area for sr o and h isotopes indicating extensive lateral migration of the fluids strontium in the brine has not equilibrated isotopically with its host rock in some cases the late stage minerals saddle dolomite calcite and anhydrite have the same 87 sr 86 sr ratios as the brine indicating that they precipitated from the brine in isotopic equilibrium

distance of movement of coarse particles in gravel bed streams distributions of distance of bedload particle movement were examined in two gravel bed streams using several hundred magnetically tagged cobbles and pebbles the compound poisson model of einstein hubbell sayre and a simple gamma function model were compared with observed distributions of moved particles and of all particles both models fit the data reasonably well for small mean displacements but notable misfits occurred in an event with large mean displacement when mean particle travel distance approaches the scale of bar spacing trapping in the bars interrupts particle progress and the dispersion process the data remain very noisy so definitive discrimination of suitable models will require trials with more than 103 particles

particle fluxes into permeable sediments comparison of mechanisms mediating deposition fine particle deposition in coarser sediment beds plays an important role in biogeochemical cycling in sediments by 1 supplying organic matter attached microorganisms and nutrients and 2 mediating interfacial fluxes through changes in permeability in some cases particles could be associated with contaminants or particles could clog pores in the sediment resulting in ecological impacts through changes in porewater chemistry e g dissolved oxygen profiles we compare two mechanisms for fine particle deposition to permeable sediments first for flat beds particle delivery by sediment grain scale flows coupled with particle retention within the sediment could result in deposition in excess of the gravitational settling second pressure driven flows across ripples may deliver additional particles directly into the sediment although sediment transport can counteract deposition flume experiments were used to measure deposition rates over a range of particle and sediment sizes for both flat and rippled beds flat bed deposition rates were greater than the particle settling velocities and comparable to the deposition rates to rippled beds under similar flow conditions an empirical expression based on parameters for flow sediment and particle conditions predicts where each mechanism dominates the deposition rate this result illustrates the potential importance of grain scale processes for the deposition of fine particles to permeable sediments regardless of bed roughness predictions of particle fate penetration into the sediment and degradation following the deposition still require a description of bed topography in addition to sediment properties

strontium isotopes in brines and associated rocks from cretaceous strata in the mississippi salt dome basin southeastern mississippi u s a abstract sr concentrations and 87 sr 86 sr ratios have been determined for brines from formations spanning most of the cretaceous in two oilfields in the mississippi salt dome basin and from local salt domes chalk sands and shales the selma group is predominantly a fossiliferous chalk whereas the remainder of the stratigraphic sequence consists of sands and shales with only minor carbonate phases the sampled interval ranges from 2000 to just over 4000 m below land surface sr concentrations range from 443 to 1718 mg kg 1 for brines from baxterville field and from 528 to 1762 mg kg 1 for brines from soso field brine 87 sr 86 sr ratios range from 0 7071 to 0 7116 at baxterville field and from 0 7083 to 0 7119 at soso field with the exception of brines from the selma chalk all 87 sr 86 sr ratios are more radiogenic than cretaceous seawater on plots of 87 sr 86 sr vs sr concentration brines from individual formations within a producing field occupy distinct non overlapping areas with the exception of a single sample in some cases individual reservoirs within formations can be distinguished brines from formations that are present in both fields which are 85 km apart do not have the same 87 sr 86 sr ratio in each field brine sr concentration increases with depth 87 sr 86 sr ratios increase with depth to 3000 m and then appear to level off these trends are interpreted to be caused by dissolution or recrystallization of carbonate minerals which contain significant amounts of non radiogenic sr and decomposition of rb rich detrital micas and k feldspar which are sources of radiogenic 87 sr salt and cap rock from domes in southeastern mississippi have an average 87 sr 86 sr ratio of 0 70707 consistent with a middle jurassic age for the louann salt in baxterville field chalk from the upper cretaceous selma group has a cretaceous seawater 87 sr 86 sr ratio of 0 7076 87 sr 86 sr ratios range from 0 7091 to 0 7111 for sr leached from sands and shales from both baxterville and soso fields if these values reflect the 87 sr 86 sr values of the easily dissolved interstitial carbonate phases they indicate that the calcite cements precipitated from sedimentary fluids which were more radiogenic than the seawater of that time but which were not as evolved as the brines which are now present alternatively they may reflect leaching of radiogenic sources

vertical gradational variability of fines deposited in a gravel framework vertical gradational structures develop as sand infiltrates into static gravel beds understanding the vertical distribution of interstitial sand deposits will improve predictions of ecological suitability and hyporheic hydrodynamics a series of flume experiments was performed to investigate fine infiltration processes four sand distributions were introduced into flows over gravel beds after each experiment bed cores were extracted and analysed in vertical layers to examine the gradational trends with depth vertical trends of fine content were highly sensitive to the relative grain size distributions of the gravel bed and the introduced sand for experiments with d15gravel d85sand ratios 15 4 and larger unimpeded static percolation was observed where sand filled the voids relatively uniformly from the bottom of the gravel layer to the top experiments with ratios 10 6 and smaller bridged sand clogged a thin layer of gravel pores near the bed surface precluding subsequent infiltration interstitial sand deposits fined with depth of penetration for all experiments which was the result of three distinct but overlapping processes i granular sorting as particles fell through the substrate smaller material preferentially passed through the voids deeper into the gravel ii bed load sorting size segregation occurs in the wake of the leading bed form as smaller particles saltate further and settle first iii hydraulic sorting smaller sand was transported preferentially as suspended load filling the deep voids of the furthest flume positions downstream finally when the experiments that formed a bridge layer were replicated with higher bed shear stresses less interstitial sand deposition was observed higher shear stresses transported coarse particles downstream more efficiently causing bridge layers to form earlier and allowing less time for suspended load to settle into the deeper substrate pores before the pathways were closed

contributions to the history of geomorphology and quaternary geology an introduction this special publication deals with various aspects of the histories of geomorphology and quaternary geology in different parts of the world geomorphology is the study of landforms and the processes that shape them past and present quaternary geology studies the sediments and associated materials that have come to mantle much of earth s surface during the relatively recent pleistocene and holocene epochs geomorphology with its concern for earth s surface features and processes deals with information that is much more amenable to observation and measurement than is the case for most geological work quaternary geology focuses mostly but not exclusively on the earth s surficial sedimentary cover which is usually more accessible than the harder rocks of the deeper past institutionally geomorphology is usually situated alongside or within academic departments of geology or geography in most english speaking countries its links are more likely to be with geography but in the united states these connections are usually shared between geography and geology although rarely in the same institution in leading institutions everywhere strong links exist between geomorphology and such cognate disciplines as soil science hydrology oceanography and civil engineering although nominally part of geology quaternary geology also has strong links with geography and with those disciplines such as climatology botany zoology and archaeology concerned with environmental change through the relatively recent past given that geomorphology concerns the study of the earth s surface i e landforms and their origin evolution and the processes that shape them and that the uppermost strata are in many cases of pleistocene and holocene age it is unsurprising that this special publication should deal promiscuously with topics in both geomorphology and quaternary studies this particular selection has been developed from a nucleus of papers presented at a conference on the histories of geomorphology and quaternary geology held in the baltic states

isotopic and trace element constraints on the origin and evolution of saline groundwaters from central missouri na ca cl groundwaters with salinities of 1 to 30 discharge from natural springs and artesian wells in mississippian carbonates and ordovician sandstones and carbonates in central missouri carbonate saturation and quartz supersaturation are maintained throughout the salinity range major and trace element and isotopic variations in the waters are used to place constraints on models for rock water interaction and regional hydrology the groundwaters have d values that range from 108 to 45 and 18 o values that range from 14 7 to 6 5 smow these data lie approximately along the meteoric water line ranging from values similar to local recharge in missouri to significantly lower values that are similar to 18 o and d for meteoric recharge in high altitude and high latitude regions of north america the more saline samples have the lowest 18 o and d contents a trend that is opposite to that observed in most other studies of saline waters the h o isotopic correlation and the range in salinity and several major and trace element concentrations in central missouri groundwaters are readily explained by a saline dilute water mixing model 87sr 86sr ratios for the groundwaters range from 0 7155 to 0 7161 these values are significantly higher than previously published values for 1 estimates of 87 sr 86 sr in phanerozoic seawater 0 7068 0 7092 and 2 carbonates of the mississippian burlington keokuk fm 0 7075 0 7105 through which some of the waters migrate as they pass to the surface nd 0 values in the groundwaters range from 10 9 to 8 1 and 147 sm 144 nd ratios range from 0 108 to 0 128 these values are similar to or lower than previously published analyses of carbonates and other authigenic phases from the burlington keokuk fm mean nd 0 7 8 0 8 1 mean 147 sm 144 nd 0 141 the h o sr and nd isotopic data and the results of model calculations preclude 1 models involving the modification of ancient seawater for the origin of the saline waters and 2 extensive interaction between the groundwaters and their host carbonates the waters apparently acquired their 18 o and d values as meteoric recharge and their 87sr 86sr and rare earth element signatures from extraformational crustal sources high 87 sr 86 sr low nd 0 low 147sm 144nd and largely preserved these isotopic signatures during subsequent migration through the carbonates chemical exchange via rock water interaction is required for isotopic exchange to occur therefore the present state of chemical equilibrium between the groundwaters and carbonate aquifer minerals may serve to limit rock water interaction and hence preserve the extraformational isotopic signatures in the waters the integration of geochemical isotopic and hydrologic data on a local and regional scale suggests a history for the central missouri groundwaters involving 1 meteoric recharge in the front range of colorado 2 dissolution of permian halite in the subsurface of kansas 3 interaction with predominantly silicate mineral assemblages in paleozoic strata and possibly precambrian basement with aquisition of crustal sr and ree signatures 4 dilution and migration to shallow aquifer levels in central missouri and 5 mixing with local meteoric recharge through mississippian carbonates with no significant change of the isotopic signatures acquired in stage 3

strontium isotope evidence on the history of oilfield brines mediterranean coastal plain israel abstract the isotopic composition of sr in oil field brines from the mediterranean coastal plain was determined in 18 drillholes 13 of which are oil producing wells the brines are characterized by salinities ranging from 35 to 93 g l tds sr from 28 to 350 mg l sr ca molar ratios from 0 011 to 0 053 and 87 sr 86 sr ratios from 0 7075 to 0 7090 e a 0 7081 0 0004 2 the brines are classified into two groups 1 a mavqi im group brines with relatively high 87 sr 86 sr ratios 0 7087 and 0 7090 sampled from elastics dolomites and anhydrites of upper miocene age 2 b heletz group brines with relatively low 87 sr 86 sr ratios 0 7075 to 0 7081 sampled from sandstones and dolomites of lower cretaceous age equations were derived to show the relations between 87 sr 86 sr ratio of the brines and the processes through which they evolved dolomitization and dissolution reprecipitation it is suggested that both groups of brines originated from mediterranean evaporated seawater during the messinian desiccation the strontium isotope composition of the seawater is reflected in that of both groups of brines the mavqi im group containing the original 87 sr 86 sr ratio 0 7088 the heletz group evolved later on through exchange reactions of those primary brines with a carbonate sequence of cretaceous age and consequently new 87 sr 86 sr ratios 0 7078 could have been developed the effect of the dissolution reprecipitation reactions on the carbonate rocks is estimated to be very slight only around 1 by weight

strontium isotopic compositions and potassium and rubidium contents of formation waters in sedimentary basins clues to the origin of the solutes abstract strontium isotopic compositions of formation waters in sedimentary basins relate primarily to sr from dissolution replacement of alkali feldspar minerals dissolution recrystallization precipitation of marine carbonate and sulfate minerals and illitization formation waters in sedimentary basins are often depleted in k but enriched in rb relative to evaporated seawater and have k rb ratios commonly between 200 and 2000 the k and rb characteristics of formation waters suggest that deep burial conversion of smectite to illite has a major influence on the evolutionary history of these solutes

87sr 86sr in waters from the lincolnshire limestone aquifer england and the potential of natural strontium isotopes as a tracer for a secondary recovery seawater injection process in oilfields the sr isotope composition of formation waters is a sensitive indicator of diagenetic processes in the host sediments mixing processes between different bodies of water and the connectivity of hydrological systems the87sr 86sr ratio of present seawater is constant worldwife while formation waters in hydrocarbon reservoirs have various values depending on the aforementioned effects in most cases different from modern seawater this forms the basis of anatural tracer technique for seawater injection projects involving characterization of the87sr 86sr ratios and sr contents of formation waters in the reservoir before injection commences followed by monitoring of these parameters in the produced water as injection proceeds this method is best suited to reservoirs in which the formation waters have low sr concentrations and87sr 86sr ratios much higher or lower than seawater available data for reservoir formation waters suggest that breakthrough recognition could be expected at 10 seawater in many sandstone reservoirs while the method would be less sensitive in carbonate reservoir or situations where the formation waters had interacted with evaporites as the associated waters tend to have high sr contents in heterogeneous but well mapped reservoirs it may be possible to obtain information about flow paths mechanismsbefore breakthrough combination with other chemical and isotopic tracers creates a very powerful tool the sr method acting as a safeguard should the batch of water containing the conventional tracers be overtaken by subsequently injected seawater the sr method could also be used for injection projects that were begun without the addition of tracers a natural analogue of a water injection process is found in the jurassic lincolnshire limestone aquifer in england where rapidly moving fresh meteoric water mixes progressively with an older saline formation water the87sr 86sr data enable quantitative modelling of this mixing process the infiltrating fresh water becomes progressively modified by dissolution of detrital carbonate and calcite cement in the limestone with depth becoming increasingly dominated by sr derived from the more soluble detrital components the saline formation water contains water molecules of meteoric origin and an87sr 86sr ratio much higher than jurassic seawater or marine carbonate the solute content has been influence by interaction of the water with non carbonate phases

the solubility of halite as a function of temperature in the highly saline dead sea brine system the dead sea brine is characterized by high ionic strength 9 10 m and a ca cl composition the lake is currently saturated with respect to aragonite gypsum and halite harned s rule is applied to calculate the saturation index of halite in the dead sea brine system this system includes brines at ionic strengths in the range of 9 l 6 1 derived from evaporating dead sea brine to facilitate the calculation we determined new interaction coefficients experimentally these were found to be a function of the ionic strength of the solution as well as of the temperature 25 c anaa mgc12 0 002611 0 00905 anac1 caci 0 001501 0 00650 3 5 c anac l m cl 0 002831 0 01972 anacl caci 0 002071 0 01851 50 c anaci m l 0 002261 0 01416 anaci cacl 0 001561 0 01315 the new parameters are used to predict the effect of temperature on halite precipitation in the lake from both the evaporating surface layer and the entire upper water body the calculated weight of halite expected to precipitate before the onset of carnallite precipitation is on the order of lo o t at the present rate of evaporation at least 120 yr will pass before that point is reached

experiments on dispersion of tracer stones under lower regime plane bed equilibrium bed load transport 1 a common approach for estimating the bed load transport rate in gravel bed streams is to relate it to deterministic channel averaged driving parameters and corresponding resistance properties of the bed material notwithstanding the proven success of this approach in modeling various morphodynamic scenarios it does not contain the mechanics necessary to relate the bulk sediment transport rate to the displacement patterns of individual particles experiments on entrainment transport and deposition of tracer stones in a flume described here were designed to address this issue predictors of statistics of bed elevation fluctuations at short timescales total and elevation specific particle entrainment rates particle step lengths mean and associated probability density function for particle virtual velocity and thickness of the active layer were developed the working hypothesis tested in this paper is that the statistics of tracer displacements can be related to channel averaged hydraulic parameters and thus linked to macroscopic aspects of bed load transport

neogene and quaternary coexisting in the geological time scale the inclusive compromise removing the tertiary and quaternary periods whilst conserving the paleogene and neogene periods in the geological timescale 2004 caused a storm of protest one response was to advocate restoring an enlarged quaternary and consigning the neogene to a minor role within the tertiary amongst an array of practical traditional sentimental and anthropocentric reasons for this response the one hard core justification was that the rigidly nested hierarchy of the geological timescale must be preserved the central objective of this paper is conserving the historically legitimate miocene present neogene period and system there are two options for conserving the quaternary concurrently with the neogene i an inclusive compromise in a flexible hierarchy and ii an upgrading of pliocene and pleistocene divisions to the level of epoch in the inclusive compromise there coexist alternative pathways through the hierarchical ranks thus geohistorians and biohistorians have two options for traversing the hierarchy from era to age as in this example using the hierarchical positioning of the calabrian age and stage either cenozoic era neogene period pleistocene epoch calabrian age or cenozoic era quaternary subera pleistocene epoch calabrian age we reaffirm that the inclusive compromise is entirely viable in so doing we i challenge the necessity of the rigidly nested hierarchy which should be capable of a little flexibility ii reject all analogies of the arbitrary and conventional chronostratigraphic hierarchy with three natural biological hierarchies iii reaffirm the integrity of the neogene extending to the present and iv see no reason to doubt the harmonious coexistence of the two options preserving the quaternary and neogene traditions in an orderly working and stable time scale in the alternative schema conserving the neogene divisions of the pliocene and pleistocene are upgraded so that the late pleistocene early pleistocene and late pliocene epochs comprise the quaternary subperiod itself equivalent to late neogene the inflexibly nested hierarchy is preserved but the tertiary is lost

strontium isotopic signatures of oil field waters applications for reservoir characterization the 87sr 86sr compositions of formation waters that were collected from 71 wells producing from a pennsylvanian carbonate reservoir in new mexico display a well defined distribution with radiogenic waters up to 0 710129 at the updip western part of the reservoir grading downdip to less radiogenic waters as low as 0 708903 to the east salinity 2800 50 000 mg l displays a parallel trend saline waters to the west pass downdip to brackish waters elemental and isotopic data indicate that the waters originated as meteoric precipitation and acquired their salinity and radiogenic 87sr through dissolution of upper permian evaporites these meteoric derived waters descended perhaps along deeply penetrating faults driven by gravity and density to depths of more than 7000 ft 2100 m the 87sr 86sr and salinity trends record influx of these waters along the western field margin and downdip flow across the field consistent with the strong water drive potentiometric gradient and tilted gas oil water contacts the formation water 87sr 86sr composition can be useful to evaluate subsurface flow and reservoir behavior especially in immature fields with scarce pressure and production data in mature reservoirs sr isotopes can be used to differentiate original formation water from injected water for waterflood surveillance strontium isotopes thus provide a valuable tool for both static and dynamic reservoir characterization in conjunction with conventional studies using seismic log core engineering and production data roger barnaby has conducted stratigraphic studies of carbonates and siliciclastics in outcrop and subsurface for 15 years he holds a ph d from virginia polytechnic institute and a b s degree from east carolina university barnaby has worked on sedimentary successions of the gulf coast permian basin alaska north slope middle east and caspian region he maintains interests in carbonate diagenesis and geochemistry gregg oetting received an m a degree in geology in 1995 from the university of texas at austin he is the author of six publications concerning geochemical and strontium isotopic variations in edwards aquifer groundwaters for the past seven years oetting has traded energy futures for leading merchant energy concerns he works for an independent consulting business in houston texas guoqiu gao received his b s and m s degrees in geology from central south university hunan china and his ph d in geology from the university of texas at austin he works for a major oil company in houston texas his current interests lie in the field of geoscience computing

chemical and boron isotope compositions of non marine brines from the qaidam basin qinghai china the general chemistry and boron isotope composition were investigated in fresh waters and hypersaline brines from the qaidam basin northern qinghai xizang tibet plateau china this basin is a large tectonically active system isolated from the ocean and composed of thick clastic and evaporite sediments the modern playas are subject to intense evaporation and are characterized by hypersaline brines as well as potash and borate evaporites the chemical composition of the dissolved solutes in the modern brines and waters reveals three main sources 1 inflow of hot springs enriched in sodium sulphate and boron evaporation of these waters leads to a high na cl ratio 1 a na cl so4 brine and an evaporite mineral assemblage of halite mirabilite borate lakes daqaidam and xiaoqaidam 2 inflow surface river waters which are modified by preferential dissolution of halite and potassium and magnesium salts characterized by a na mg cl solute type with low na cl 1 brcl licl and bcl ratios and 3 ca chloridic subsurface brines which are controlled by both salt dissolution and dolomitization processes evaporation and salt crystallization of mixtures of the latter two types leads to a marine like brine e g na mg cl type nacl ratio 1 and mineral assemblages similar to that predicted for progressive evaporation of seawater e g qarhan playa halite sylvite carnallite bischofite the 11 b values of the input waters to the qaidam basin range of 0 7 to 10 9 vs nbs 951 and brines from salt lakes 0 5 to 15 0 are similar to those of associated granitic rocks 11b 2 3 to 3 7 n 3 and hence indicate the non marine origin of these fluids the highest 11b values are associated with fluids with low bli ratios indicating selective removal of elemental boron and 10b by adsorption onto clay minerals the magnitude of 11b enrichment due to adsorption is 15 20 and thus non marine brines are well distinguished from marine derived brines 11b of 39 to 59 preserving the large isotopic difference 40 of their source waters it is proposed to use this distinctive isotopic signature for tracing the origin of ancient evaporite environments

strontium boron oxygen and hydrogen isotope geochemistry of brines from basal strata of the gulf coast sedimentary basin usa abstract significant spatial heterogeneities exist in the stable isotopic composition of saline formation waters from reservoirs of the smackover formation upper jurassic we focused on the southwest arkansas shelf a structurally simple portion of one of the interior basins of the northern gulf coast sedimentary basin here faulting and facies changes juxtapose dominantly oolitic carbonate strata against basal evaporites red beds and siliciclastics as well as metamorphosed basement rocks brines from this area have exceptionally high br and alkali element concentrations and have spatially heterogeneous hydrogen sulfide concentrations strontium boron oxygen and hydrogen isotope compositions exhibit coherent relations with other aspects of brine geochemistry sr isotope compositions range from those expected for carbonates and evaporites deposited from jurassic seawater 0 7071 to radiogenic ratios as high as 0 7107 generally most radiogenic sr isotope values are associated with h 2 s rich waters which also have elevated alkali element li b k rb concentrations these alkali element rich waters are associated with portions of the south arkansas fault system which reach basement boron isotope compositions are similarly heterogeneous ranging from values of 26 to 50 brines with highest b contents are most depleted in 11 b consistent with boron input from brines generated from high temperature siliciclastic diagenetic reactions normalizing b contents to br in the brines reveals a reasonable mixing trend between a dead sea type composition and texas gulf coast type shale sand reservoir waters oxygen and hydrogen isotope data exhibit regional variations which are controlled by meteoric water invasion along the northern limb of the southwest arkansas fault which has surface expression although oxygen isotope compositions are often near equilibrium with respect to reservoir carbonate it is more difficult to ascribe trends in d values to local water rock interaction the stable isotope trends can be explained either in terms of an evolved marine evaporite brine or a water evolved via water rock interaction and mixing with meteoric water in the vicinity of the southwest arkansas fault spatial heterogeneity in isotopic composition of formation waters from this relatively restricted study area suggests that assumptions of a homogeneous sr reservoir in dating regional mineralization events require careful assessment in ancient systems

bed material transport estimate in large gravel bed rivers using the virtual velocity approach this paper reports on a first attempt of using the virtual velocity approach to assess sediment mobility and transport in two wide and complex gravel bed rivers of northern italy displacement length and virtual velocity of spray painted tracers were measured in the field also the thickness of the sediment active layer during floods was measured using scour chains and post flood morphological changes as documented by repeated survey of channel cross sections the effects of eight and seven floods were studied on the tagliamento and brenta rivers where 259 and 277 spray painted areas were surveyed respectively in the tagliamento river 36 of the spray painted areas experienced partial transport whereas in the brenta river this accounted for 20 whereas full removal gravel deposition was observed on 37 and 26 of these areas on the tagliamento and brenta rivers respectively the mean displacement length of particles the thickness of the active layer and the extent of partial transport are well correlated with the dimensionless shear stress the virtual velocity approach allowed calculation of bed material transport over a wide range of flood magnitudes annual coarse sediment transport was calculated up to 150 for the tagliamento and 30 103 m3 yr 1 for the brenta the outcomes of this work highlight the relevance of partial transport condition as it could represent more than 70 of the total bed material transported during low magnitude floods and up to 40 for near bankfull events results confirm that bed material load tends to be overestimated by traditional formulas copyright 2016 john wiley sons ltd

strontium isotope trends during diagenesis in ore bearing carbonate basins strontium isotope studies 120 analyses were carried out on ore and gangue minerals from five ore districts in different carbonate basins most of the samples were separated from consecutive diagenetic generations even for diverse stratigraphic positions and mineralogies very consistent trends are recognized in all cases87sr 86sr ratios increase with advancing diagenetic stage however each district shows a different behaviour in the magnitude of increase over the first diagenetic generation which ideally is close to contemporaneous seawater the increase of the strontium ratios in the subsequent diagenetic generations is explained by equilibration during crystallization with fluids evolving towards more radiogenic compositions this is interpreted as a consequence of the reaction of the fluids with rb bearing phases mainly detrital clay minerals variation ranges of87sr 86sr ratios can constitute a sensitive tool for determining the stage of basin evolution in a similar way as vitrinite reflectance or illite crystallinity this method has the disadvantage that the increase of radiogenic strontium depends not only on the evolution stage i e temperature pressure and time but also on the amount of rb bearing minerals present in the basin on the other hand this method has the important advantage that within a given basin this last parameter can be modelled each evolution stage is recorded in the cements or crystallization generations by its strontium isotope signatures which tend towards increased radiogenic values with advancing diagenesis

on the secular variations in the composition of phanerozoic marine potash evaporites in a recent paper l a hardie proposed that the secular changes in the mineralogy of marine nonskeletal limestones and in the mineralogy of marine potash evaporites during the phanerozoic are the result of changes in the composition of seawater caused primarily by fluctuations in the flux of seawater through mid ocean ridges he suggested that even quite small variations 25 in this flux have a profound effect on the composition of seawater we show that the effects of changes in the hydrothermal flux are much smaller than he proposed nevertheless a doubling of the hydrothermal flux could probably alter the composition of seawater sufficiently to affect the mineralogy of marine potash evaporites an alternative explanation for the variations in the mineralogy of these deposits invokes differences in the degree of dolomitization during the evaporation of seawater the apparent near constancy of the k sup content of seawater during the phanerozoic supports this hypothesis it seems likely that during periods of rapid seafloor spreading the rate of seawater cycling is greater than today that sea level is higher that very large carbonate platforms are more abundant and that changes in seawater chemistry together with increases in dolomitization during the evaporation of seawatermore lead to mgso sub 4 free potash deposits the relative importance of these several effects can probably be determined with certainty only when we have analyses of relatively unaltered seawater from the several phanerozoic periods 27 refs 1 fig 1 tab less

using passive integrated transponder pit tags to investigate sediment transport in gravel bed rivers abstract in gravel bed rivers measuring the displacement of individual grains by fluid flow is essential in order to understand sediment transport processes and to investigate changes in channel morphology we present preliminary results of a new technique that traces pebble movements by inserting 23 mm passive integrated transponders pit into individual clasts because each pit has its own signal identification this technique is ideal for tracking the individual movements of episodically transported particles in gravel bed rivers two hundred and four tagged particles were inserted into a 130 m long reach of a gravel bed river with a 2 slope and a bed material with a d50 of 70 mm the b axis size of the tagged particles ranged from 40 mm to 250 mm recovery percentages after two competent floods were 96 and 87 clearly demonstrating the effectiveness of this new technique buried particles can be recovered at a depth of 0 25 m pit tags are also suited for long term studies over several years

mechanisms of sulfate removal from subsurface calcium chloride brines heletz kokhav oilfields israel abstract the evolution of the ca chloride brines in the heletz formation lower cretaceous in the southern coastal plain of israel was reconstructed through the study of its sulfate concentration and isotopic composition particular emphasis was given to the brine oil interaction in the oilfields and to the sulfate depletion and lower so4 cl ratio in brines in contact with hydrocarbons oil brines relative to oil free from dry wells in the same oilfields a method is presented for a calculation of the amount of sulfate removed from the original seawater in the various stages of its evolution to ca chloride brine these stages include evaporation dolomitization and sulfate reduction in different stages of its evolution from early diagenetic processes to the contact with crude oil in the present study based on the 34sso4 and so4 cl ratio it was found that in the heletz brines most of the sulfate 80 94 was removed from the original seawater prior to their interaction with the hydrocarbons and only a negligible fraction of few percent of the sulfate was removed during the crude oil water contact the ca chloride brines evolved from messinian upper miocene seawater that underwent evaporation during the desiccation of the mediterranean sulfate was removed from messinian lagoon s during gypsum precipitation due to evaporation and dolomitization bacterial sulfate reduction further depleted the brine in sulfate and changed its isotopic composition from its original miocene seawater composition of 34sso4 20 o 26 o overall some 50 of the original sulfate as normalized to chloride was removed from the original lagoon through the above processes mostly by gypsum precipitation eastward migration of the messinian ca chloride brine into the heletz formation was accompanied by dolomitization of the country rock final depletion of sulfate from the brines took place and possibly still occurs in the presence of crude oil in the oilfields the two oil producing fields heletz and kokhav occupy different areas on a rayleigh distillation diagram sulfate depletion in both fields is accompanied by an increase in 34sso4 which reaches a maximum value of 59 o the above correlation is explained by bacterial sulfate reduction facilitated by the contact with the crude samples collected from the same boreholes at time intervals of several months show two opposing trends sulfate concentration decrease accompanied by increase in 34sso4 and vice versa while the first can be explained as in situ bacterial sulfate reduction the latter attest to subsurface brine migration as would be expected in oil producing fields

origin of groundwater salinity current seawater vs saline deep water in a coastal karst aquifer based on sr and cl isotopes case study of the la clape massif southern france origin of groundwater salinity current seawater vs saline deep water in a coastal karst aquifer based on sr and cl isotopes case study of the la clape massif southern france a b s t r a c t in this study a typical coastal karst aquifer developed in lower cretaceous limestones on the western med iterranean seashore la clape massif southern france was investigated a combination of geochemical and isotopic approaches was used to investigate the origin of salinity in the aquifer water samples were collected between 2009 and 2011 three groundwater groups a b and c were identified based on the hydrogeological setting and on the cl a concentrations average and maximum cl a concentrations in the recharge waters were calculated cl ref and cl ref max to be 0 51 and 2 85 mmol l respectively group a includes spring waters with cl a concentrations that are within the same order of magnitude as the cl ref concentration group b includes groundwater with cl a concentrations that range between the cl ref and cl ref max concentrations group c includes brackish groundwater with cl a concentrations that are significantly greater than the cl ref max concentration overall the chemistry of the la clape groundwater evolves from dominantly ca hco 3 to nacl type on binary diagrams of the major ions vs cl most of the la clape waters plot along mixing lines the mixing end members include spring waters and a saline component current seawater or fossil saline water based on the br cl molar ratio the hypothesis of halite dissolution from triassic evaporites is rejected to explain the origin of salinity in the brackish groundwater groundwaters display 87 sr 86 sr ratios intermediate between those of the limestone aquifer matrix and current mediterranean seawater on a sr mixing diagram most of the la clape waters plot on a mixing line the end members include the la clape spring waters and saline waters which are similar to the deep geo thermal waters that were identified at the nearby balaruc site the 36 cl cl ratios of a few groundwater samples from group c are in agreement with the mixing hypothesis of local recharge water with deep saline water at secular equilibrium within a carbonate matrix finally phreeqc modelling was run based on cal cite dissolution in an open system prior to mixing with the balaruc type saline waters modelled data are consistent with the observed data that were obtained from the group c groundwater based on several trac ers i e concentrations and isotopic compositions of cl and sr calculated ratios of deep saline water in the mixture are coherent and range from 3 to 16 and 0 to 3 for groundwater of groups c and b respectively with regard to the la clape karst aquifer the extension of a lithospheric fault in the study area may favour the rise of deep saline water such rises occur at the nearby geothermal balaruc site along another lithospheric fault at the regional scale several coastal karst aquifers are located along the gulf of lion and occur in mezosoic limestones of similar ages the 87 sr 86 sr ratios of these aquifers tend toward values of 0 708557 which suggests a general mixing process of shallow karst waters with deep saline fossil waters the occurrence of these fossil saline waters may be related to the introduction of seawater during and after the flandrian transgression when the highly karstified massifs invaded by seawater formed islands and peninsulas along the mediterranean coast

threshold for particle entrainment into suspension laboratory observations regarding the limit conditions for particle entrainment into suspension are presented a high speed video system was used to investigate conditions for the entrainment of sediment particles and glass beads lying over a smooth boundary as well as over a rough bed the results extend experimental conditions of previous studies towards finer particle sizes a criterion for the limit of entrainment into suspension is proposed which is a function of the ratio between the flow shear velocity and particle settling velocity observations indicate that particles totally immersed within the viscous sublayer can be entrained into suspension by the flow which contradicts the conclusions of previous researchers a theoretical analysis of the entrainment process within the viscous sublayer based on force balance considerations is used to show that this phenomenon is related to turbulent flow events of high instantaneous values of the reynolds stress in agreement with previous observations in the case of experiments with a rough bed a hiding effect was observed which tends to preclude the entrainment of particles finer than the roughness elements this implies that as the ratio between particle and roughness element sizes becomes smaller progressively higher bed shear stresses are required to entrain particles into suspension on the other hand an overexposure effect was also observed which indicates that a particle moving on a smooth bed is more prone to be entrained than the same particle moving on a bed formed by identical particles

application of the trace element and isotope geochemistry of strontium to studies of carbonate diagenesis carbonate rocks and natural waters exhibit a wide range in the concentration and isotopic composition of strontium this wide range and the quantifiable covariation of these parameters can provide diagnostic tools for understanding processes of fluid rock interaction careful consideration of the uncertainties associated with trace element partitioning sample heterogeneity and fluid rock interaction mechanisms is required to advance the application of the trace element and isotope geochemistry of strontium to studies of diagenesis goundwater evolution ancient seawater chemistry and isotope stratigraphy a principal uncertainty involved in the application of sr concentration variations to carbonate systems is the large range of experimental and empirical results for trace element partitioning of sr between mineral and solution this variation may be a function of precipitation rate mineral stoichiometry crystal growth mechanism fluid composition and temperature calcite and dolomite in ancient limestones commonly have significantly lower sr concentrations 20 70 p p m than would be expected from published trace element distribution coefficient values and sr ca ratios of most modern sedimentary pore waters this discrepancy probably reflects the uncertainties associated with determining distribution coefficient values as techniques improve for the analytical measurement and theoretical modelling of sr concentration and isotopic variations the petrological analysis of carbonate samples becomes increasingly important the presence of even small percentages of non carbonate phases with high rb concentrations and high 87 sr86 sr values such as clay minerals can have significant effects on the measured 87 sr 86 sr values of carbonate rocks due to the decay of 87rb to 87 sr for example a permian marine limestone with 50 p p m sr and 1 p p m rb will have a present day 87 sr 86 sr value that is 2 10 4 higher than its original value this difference is an order of magnitude greater than the analytical uncertainty and illustrates the importance of assessing the need for and accuracy of such corrections a quantitative evaluation of the effects of water rock interaction on sr concentrations and isotope compositions in carbonates strengthens the application of these geochemical tracers geochemical modelling that combines the use of trace elements and isotopes can be used to distinguish between different mechanisms of water rock interaction including diffusive and advective transport of diagenetic constituents in meteoric pore fluids during the recrystallization of carbonate minerals quantitative modelling may also be used to construct diagnostic fluid rock interaction trends that are independent of distribution coefficient values and to distinguish between mixing of mineral end members and fluid rock interaction

virtual velocity of sand transport in water using the 160 m long flume at tsukuba university we undertook an experiment to provide a first estimate of the virtual velocity of sand in the size range 0 5 2 0 mm for the flow velocity used in our experiment this sediment size range would conventionally be regarded as suspended sediment the virtual velocity is found to be 37 41 of the flow velocity paradoxically virtual velocity decreases as particle size decreases such a lower virtual velocity of finer sediment is not inconceivable first trapping of the sediment appears to be a function of bed roughness and there is a probable relationship between bed roughness and trapping efficiency for particles of different sizes secondly finer particles are more likely to find sheltered positions on a rough bed and thus experience lower mobility relative to the more exposed coarser grains as observed for bedload transport thirdly the virtual velocity of particles undergoing bedload transport has been found in some instances to be lower for finer clasts we combine our data with previous studies of virtual velocity of bedload to develop for the first time an hypothesis for an holistic analysis of sediment movement in rivers

stable isotope evidence for the origin of diagenetic carbonate minerals from the lower jurassic inmar formation southern israel the oxygen isotope compositions of diagenetic carbonate minerals from the lower jurassic inmar formation southern israel have been used to identify porewater types during diagenesis changes in porewater composition can be related to major geological events within southern israel in particular saline brines played an important role in late pliocene pleistocene dolomitization of these rocks diagenetic carbonates included early siderite 18osmow 24 4 to 26 5 13cpdb 1 1 to 0 8 late dolomite ferroan dolomite and ankerite 18osmow 18 4 to 25 8 13cpdb 2 1 to 0 2 and calcite 18osmow 21 3 to 32 6 13cpdb 4 2 to 3 2 the petrographic and isotopic results suggest that siderite formed early in the diagenetic history at shallow depths the dolomitic phases formed at greater depths late in diagenesis crystallization of secondary calcite spans early to late diagenesis consistent with its large range in isotopic values a strong negative correlation exists between burial depth temperature and the oxygen isotopic compositions of the dolomitic cements in addition the 18o values of the dolomitic phases in the northern negev and judea mountains are in isotopic equilibrium with present formation waters this behaviour suggests that formation of secondary dolomite post dates the tectonic activity responsible for the present relief of southern israel upper miocene to pliocene and that the dolomite crystallized from present formation waters such is not the case in the central negev in that locality present formation waters have much lower salinities and 18o values indicating invasion of freshwater and are out of isotopic equilibrium with secondary dolomite recharge of the inmar formation by meteoric water in the central negev occurred in the pleistocene and halted formation of dolomite

sulfur isotope constraints on the formation of mgso4 deficient evaporites in the qarhan salt lake western china abstract the qarhan salt lake qsl in the qaidam basin in western china is the largest brine potash deposit in the world the formation of mgso4 deficient evaporites in the qsl whether from the evaporation of river waters with high na and cl levels bacterial sulfate reduction bsr in brines resulting in so42 depletion or the mixing of the river and spring waters remains controversial the 34s values of 33 intercrystalline brines and 10 gypsum samples from a sediment core isl1a collected in the qsl were presented in this study combining these results with previously reported major ionic concentrations total dissolved solids tds and 34s values of different waters and 87sr 86sr ratios of sediments it was concluded that 1 34s values of the intercrystalline brines 6 7 to 12 1 and gypsum 8 1 to 10 1 suggested that the bsr was insignificant in the qsl these values were dominated by those of inflowing waters and the evaporation process 2 river waters with high na and cl levels were unable to form mgso4 deficient evaporites in the qsl a strong positive correlation of na and cl equivalents coupled with high na cl tds ratios suggested that the large amount of solutes in golmud river waters results from the dissolution of halite rather than the chemical weathering of rocks and 3 the flowing system of the river and spring in the past 50 kyr was similar to the modern supplying system and mixing of river and spring waters was responsible for the precipitation of evaporites in the qsl

hierarchical subdivision of the cenozoic era a venerable solution and a critique of current proposals abstract if tertiary and quaternary are to be formally defined and ranked then only one topology and two ranking options for the major subdivisions of the cenozoic era are consistent with the principles of hierarchical classification these are 1 for the tertiary and quaternary to be ranked as suberas with the paleogene and neogene ranked as periods of the tertiary or 2 for the tertiary and quaternary to be ranked as periods with the paleogene and neogene ranked as subperiods of the tertiary the first option would leave the period rank empty for quaternary time however so the second option is preferred here in neither case is an extension of the neogene to the present permitted if desired however early cenozoic and late cenozoic could be defined as formal unranked chrons with the latter term providing an unambiguous expression for the same concept as the extended neogene attempts to justify an extended neogene by reference to a statement arising from the 1948 international geological congress fail because they are based on a misinterpretation of that statement likewise an appeal to the alleged original meaning of the neogene fails because it is factually superficial and would also have unacceptable consequences if applied as a general principle to the rest of the time scale four arguments against a ranked tertiary and or quaternary involve the status of these names as parts of an obsolete classification the disparity in their durations an analogy between them and the unranked precambrian and their supposed ambiguity these arguments are readily refuted arguments in favor of a ranked tertiary and quaternary include the continuing widespread use of these names their practical relevance for geologic maps and their role in honoring the pioneers of stratigraphy a recent recommendation by the international commission on stratigraphy ics would decouple the beginning of the quaternary from the beginning of the pleistocene have the neogene and pliocene overlap the tertiary quaternary boundary and have the gelasian age belong to both the pliocene and the quaternary these results violate the existing guidelines of the ics this same proposal would also regard the quaternary as a subera within the neogene period the latter being extended to the present however this arrangement violates the most fundamental rule of hierarchical classification in that a unit of superior rank would be included entirely within a unit of inferior rank given these problems the international union of geological sciences iugs must reject the ics recommendation an improved version of the ics proposal with the quaternary ranked as a period and the paleogene and extended neogene ranked as suberas would still prohibit the tertiary from being ranked and would either violate simpson s rule or else require a new name for the traditional concept of the neogene because the classification of the cenozoic advocated here is strictly hierarchical violates none of the existing guidelines of the ics obeys simpson s rule requires no new names allows the tertiary quaternary paleogene and neogene to be formally ranked and has been in general use for more than a century it is to be preferred only two current options for defining the quaternary and pleistocene are valid namely to leave the beginnings of these units where they are now vrica gssp at 1 8 ma or to move both to the piacenzian gelasian boundary monte san nicola gssp at 2 6 ma the latter option is not prohibited by lyell s types of the older pliocene nor after 2008 by the existing guidelines of the ics but if enacted could jeopardize the stability of the rest of the standard global time scale

comparative analysis of sulfur isotope behavior in the basins with evaporites of chloride and sulfate types abstract the pripyat trough and the caspian depression are examples of basins with chloride and sulfate type evaporite formations respectively patterns of sulfur isotope distribution in these basins are essentially different sulfur isotopic composition of sulfate minerals in the caspian depression becomes lighter from the gypsum stage 34 s 13 9 0 3 toward the chloride stage 12 7 0 2 an opposite isotopic trend occurs in the pripyat trough 34s are respectively 22 8 1 0 and 25 3 0 5 pyrite formed in the chloride stage in the caspian depression is significantly depleted in 34s with respect to the initial sulfate of the basin 34 s sulfate py 22 5 2 1 34s sulfate py in the pripyat trough is lower 17 6 1 2 diagenetic anhydrites from the intersaliferous and subsaliferous formations are enriched in 34s relative to the sulfur isotope values measured from the anhydrites in the main salts this enrichment is higher in the pripyat trough average 34s 2 7 5 2 than in the caspian depression 0 9 2 1 the above differences are well explained in the terms of chemical systems that are limited or unlimited with respect to sulfur during the sulfate reduction process brines act as sulfur limited systems in chloride type basins and as sulfur unlimited systems in sulfate type ones

strontium isotopic composition of hot spring and mineral spring waters japan abstract in japan hot springs and mineral springs are distributed in quaternary and neogene volcanic regions as well as in granitic sedimentary and metamorphic regions lacking in recent volcanic activity the87sr 86sr ratio was determined in hot spring and mineral spring waters obtained from 47 sites the ratios of waters from quaternary and neogene volcanic regions were in the range 0 703 0 712 which is lower than that from granitic sedimentary and metamorphic regions 0 706 0 712 the geographical distribution of the ratios coincides with the bedrock geology and particularly the ratios of the waters in quaternary volcanic regions correlate with those of surrounding volcanic rocks these features suggest that subsurface materials control the87sr 86sr ratios of soluble components in the hot spring and mineral spring waters

problems in chronostratigraphy stages series unit and boundary stratotypes global stratotype section and point and tarnished golden spikes abstract stratigraphy is a magnificent subject magnificent in its breadth and scope magnificent in its importance to so many lines of human endeavor it is essentially that branch of geology which deals with the arrangement the distribution and the chronological succession of rock strata and other associated rock bodies with respect to any or all of the various characters properties and attributes which rocks may possess hedberg 1958 p 1881 chronostratigraphy the temporal ordering of geologic strata is at the heart of earth history in reviewing chronostratigraphic theory from d orbigny to hedberg we see that concepts and practices have evolved under pressure of constant improvements in time control and data quality such stimuli are naturally felt more strongly in the youngest part of the stratigraphic record where dating is most precise and the biostratigraphic data are most abundant and well preserved it is not surprising therefore to find that chronostratigraphy is conceptually more advanced in the cenozoic erathem than in the mesozoic and paleozoic erathems where biostratigraphy and chronostratigraphy are widely confused evidently out of necessity taking the five inter series boundaries in the cenozoic erathem as case histories we review their current status in relation to the lower boundary of the lowest standard stage above the boundary in light of the hierarchical principle recommended in the international stratigraphic guide hedberg 1976 salvador 1994 in each instance what should be a simple nested relationship turns out to be complex and difficult and in the cases of the proposed global stratotype section and point gssps for the eocene oligocene series boundary and the paleocene eocene series boundary there are discrepancies so large with regard to the base of the rupelian and ypresian standard stages respectively that some essential relaxation of the hierarchic rule seems to be required if the historic value of these long known stages is not to be violated since stage boundaries should not be defined a posteriori to fit series boundaries we propose here to reconsider the role of the standard stage as the obligate elemental subdivision in a rigidly hierarchical chronostratigraphic scale and suggest that series and subseries should be formalized and their boundaries defined by gssps we do not suggest that stages be abandoned on the contrary we propose to integrate them in a two step hierarchical chronostratigraphic framework so as to use them in complementary fashion with series and subseries however the boundary concept is more appropriate for stage than the gssp we recognize the need for precise and globally valid chronostratigraphic correlations based on gssps in attempts to understand the earth system while at the same time we emphasize the need for conceptual continuity with regard to the central place that the stage has played in chronostratigraphy over several decades

formation of a salt plume in the coastal plain aquifer of israel the be er toviyya region the formation and development of a salt plume salinity up to 800 mg cl 1 1 in the inner part of the coastal plain aquifer of israel is analyzed massive groundwater exploitation during the 1950s caused a large drop in the water level and formation of a hydrologic depression in the be er toviyya kefar warburg area the depression reached a maximal depth during the late 1960s thereafter a reduction in the rate of pumpage led to restoration of water levels and shallowing of the depression until its complete disappearance towards the end of the 1980s a spot of high salinity first appeared in 1956 following a deep drawdown in the water levels this saline plume has been continuously expanding with increasing salinity concentrations 200 800 mg cl 1 1 in its center the average rate of radial expansion was about 50 m year 1 the expansion and salinization did not cease as the depression disappeared rather equalization of water levels in wells situated within the plume area with those of situated along its margins resulted in the salinization of the latter within a period of 1 year mass balances for water and chloride contents were made for the period 1967 1990 taking into consideration the storage change pumpage natural replenishment and artificial recharge the lateral inflow to the depression is estimated as 60 106 m3 upon addition of the chloride balance and taking into consideration the chloride concentrations of the surrounding fresh water and the apparent possible end member of the saline source based on geochemical considerations the saline inflow is estimated as 40 60 106 m3 these estimates indicate that a large amount of saline water penetrated into the aquifer of about half of the natural replenishment of the study area with an estimated salinity of 1900 2700 mg cl 1 1 it is suggested that the salt plume was formed as a result of a drop in water level combined with a flow of underlying saline water bodies from deeper strata the chemical composition of the groundwater points to the existence of two saline water bodies of ca chloride composition and a marine brcl ratio 1 saline water with low nacl 0 6 so4cl and b cl ratio 2 saline water with higher nacl 0 6 so4cl and b cl ratios these chemical compositions resemble ca chloride saline waters found in other locations in the coastal plain aquifer and in underlying formations the saline water bodies may occur in either pockets at the bottom of the aquifer or lumachelle and sandstone layers of high hydraulic conductivity in underlying sediments

a strontium isotopic study of mineral and surface waters from the cezallier massif central france implications for mixing processes in areas of disseminated emergences of mineral waters abstract surface and mineral waters from a geothermal area cezallier in the centre of the massif central france were analysed for sr isotopes sr and major elements in order to use sr isotopes to investigate the discharge of a mineralised water area especially in the case of disseminate mineralised water emergences the 87 sr 86 sr ratios of mineralised waters ranged from 0 715541 to 0 716773 the variation in 87 sr 86 sr values was small for the 5 mineral springs sampled over two periods 5 10 6 14 10 6 regarding the reproductivity of the 87 sr 86 sr ratio measurements no differences can be seen and the 87 sr 86 sr ratio of mineral waters can be considered to be constant with time the 87 sr 86 sr ratios of surface waters collected along the zagat river ranged from 0 705303 to 0 715091 the lowest values were always observed in the headwaters the difference in the 87 sr 86 sr ratios between the two sampling periods was 22 10 4 and can be related to the hydrological situation low or high flow the 87 sr 86 sr ratios of surface waters collected in the drain ranged from 0 715072 to 0 716585 the difference in the 87 sr 86 sr ratios between the two sampling periods is 11 10 4 for the drain headwaters and 13 10 5 at the outlet of this area likewise these variations can also be related to the hydrological situation plots of 87 sr 86 sr vs 1 sr ratios show two distinct binary mixing trends and the existence of at least four end members a mixing parameter f giving the proportions of the two components can be estimated for assumed 87 sr 86 sr ratio and sr content values of the pure end members an estimate of the mineral water discharge can be calculated using the results of the mixing model and the measured flow in the drain area the mixing model gives an estimate 0 5 1 l s 1 or 10 13 of mineral water in the total flow a similar calculation was done for the river where the mineral water flow was 0 96 l s 1 3 5 m3 h 1 100 m downstream from the bridge in april 1994 and 6 m3 h 1 20 m downstream from the bridge in september 1994

strontium isotopic composition of oil field and gas field waters japan abstract the87sr 86sr ratios of 10 formation waters in petroleum and natural gas reservoirs along the western coast of northeastern honshu japan ranged from 0 7052 to 0 7084 and are distinctly lower than the ratio in seawater this forms a marked contrast to oil field brines from the u s a which have higher87sr 86sr ratios taking into consideration that petroleum and natural gas in japan accumulate in volcanic rocks derived from intense submarine volcanism in the middle miocene the87sr 86sr ratios of the water samples are explained in terms of the isotope exchange between waters containing seawater sr and reservoir rocks with lower ratios

s isotope studies of shallow water laminated gypsum and associated evaporites upper permian east greenland abstract three types of primary subaqueous gypsum occur in the karstryggen formation upper permian of east greenland 1 planar laminated gypsum having a narrow 34 s range of 10 2 to 10 4 cdt 2 algal laminated gypsum 9 2 to 12 0 and 3 bottom nucleated gypsum crystals 11 6 to 11 7 type 3 was deposited from a residual brine in the basin while types 1 and 2 consist of seawater or mixed fresh water seawater derived sulphate with varying contribution of reoxidized sulphur originally deposited as sulphide or organic sulphur diagenetic nodular gypsum 7 3 to 10 8 was formed by redistribution of marine or mixed fresh water seawater derived brines which precipitated the laminated gypsum with contribution of sulphate originally precipitated as sulphide or organic sulphur in the organic rich sediments

a strontium isotopic study of formation waters from the illinois basin u s a abstract the isotopic composition of sr has been measured in 73 formation water samples from paleozoic strata in the illinois basin 87sr 86sr ratios range from 0 7079 to 0 7108 with the exception of four samples the waters are more radiogenic than corresponding paleozoic sea water values the relatively narrow range of slightly elevated 87sr 86sr rations is uniformly distributed in waters throughout the stratigraphic column and in silurian waters across the basin isotopic analyses of core samples from reservoir rocks show an absence of water rock sr isotopic equilibration basin lithology and analyses of detrital rock units indicate that clay minerals in shales and in quartz sandstone matrices represent the only significant source of radiogenic sr for the waters silurian and devonian water show a two component mixing relation which suggests that they comprise a single hydrogeological system that evolved when radiogenic water from new albany shales entered silurian devonian carbonate rocks and mixed with marine interstitial water regional migration of the waters and associated petroleum within the silurian devonian strata proposed in other studies is consistent with the sr isotopic data under favorable circumstances subsurface waters are capable of retaining a sr isotopic recor of their evolution

strontium isotope constraint on the genesis of crude oils oil field brines and kuroko ore deposits from the green tuff region of northeastern japan abstract crude oils from akita to northern niigata oil fields in the green tuff region of northeastern japan have distinctly uniform 87 sr 86 sr ratios 0 7080 0 7082 while those from the southern niigata oil field contain more radiogenic strontium 0 7095 0 7102 the regional variation in the strontium isotopic composition of crude oils is also reflected in their sulfur contents and sulfur isotopic compositions and may be attributed to the regional heterogeneity of marine organic sediments from which the crude oils were ultimately derived the 87 sr 86 sr ratios of most oil field brines 0 7061 0 7084 however are different from and vary more locally than those of the accompanying crude oils this finding supports the view that strontium and by inference some other dissolved solutes in the brines may have evolved during diagenesis by reaction of a connate and or a meteoric water with rocks in the green tuff region barites in the sulfide ore and anhydrites and gypsums in the sulfate sekko ore from the fukazawa and kosaka kuroko deposits in the hokuroku district are divided by the 87 sr 86 sr ratio of 0 7081 0 0001 which is identical to that of crude oils from nearby oil fields this similarity in ratios lends support to the conclusion that the kuroko base metal deposits and crude oil deposits were ultimately derived from a common organic sediment named pumos primitive undifferentiated metalliferous organic sediments

experimental study on coarse grain saltation dynamics in bedrock channels saltation of bed load particles on bedrock surfaces is important for landscape evolution and bedrock incision in steep landscapes however few studies have investigated saltation in bedrock channels where unlike alluvial channels the bed roughness height and the sediment size may be independent to address this data gap we measured the saltation hop height hop length and velocity of gravel saltating over a planar bed using 80 160 readings from high speed photography and direct measurements two separate dimensional analyses are used one leading to a bed shear stress scaling and another leading to a froude number fr scaling our new saltation data coupled with numerous data from previous studies suggest that both shear stress and fr scaling analyses are valid in characterizing bed load saltation dynamics with bed roughness ranging from smooth to alluvial beds however the fr approach has the advantages that 1 there is no need to estimate a critical shields stress c which alone can vary up to 2 orders of magnitude e g 0 001 0 1 due to changes in relative bed roughness and slope and 2 the fr based scaling fits the saltation data set better in a least squares sense results show that the saltation velocity of bed load is independent of grain density and grain size and is linearly proportional to flow velocity saltation height has a nonlinear dependence on grain size saltation length increases primarily with flow velocity and it is inversely proportional to submerged specific density our results suggest that either c or bed roughness coefficient must be properly estimated to yield accurate results in saltation abrasion models

saline groundwater in israel its bearing on the water crisis in the country abstract one of the major causes for the deterioration of water quality bearing heavily on the water crisis in israel is the ongoing contamination of its water resources by saline water bodies the present paper reviews the geochemical processes forming saline water lists and explains certain chemical and isotopic parameters which enable understanding these processes and describes the saline groundwater bodies and various salinization phenomena occurring in the country s various aquifers deterioration of groundwater in israel is caused by numerous natural processes such as encroachment of sea water migration of connate highly pressurized brines penetrating into fresh groundwater by subsurface dissolution of soluble salts originating in surrounding country rocks and by water rock interaction in addition to sea water two saline water bodies were identified as the main factors causing salinization of fresh groundwater a ca chloride brines encountered in the jordan dead sea rift valley in various parts of the negev and of the coastal plain and b na chloride saline water identified in the subsurface of the negev and in the southern part of the coastal plain intensive exploitation of groundwater in israel has disturbed the natural equilibrium which prevailed between fresh and saline water the newly established groundwater flow regimes have facilitated the migration of saline water bodies their participation in the active hydrological cycle and the progressive contamination of fresh groundwater these processes which were not anticipated by planners and water resources managers emphasize that large scale groundwater exploitation was undertaken without giving sufficient consideration to the occurrence and subsurface migration of saline water and brines

a strontium isotope study of the vc 1 core hole and associated hydrothermal fluids and rocks from valles caldera jemez mountains new mexico chemical and strontium isotopic analyses have been performed on 10 geothermal waters from the valles caldera jemez mountain region as well as 10 rock samples collected in the vc 1 scientific core hole the 87sr 86sr values of other rocks sampled in the jemez mountains have also been used in this study to understand relations between the fluids and rocks of the volcanically driven geothermal system and the lateral outflow plume discharging down the jemez fault zone the strontium content of groundwater is linked to the host rock composition the aquifer temperature and therefore the solubility of sr containing minerals low sr concentrations in the fluid are found with a high temperature and or volcanic host rocks whereas high sr concentrations are characteristic of a low temperature and or a paleozoic sedimentary aquifer important variations of the 87sr 86sr value in hydrothermal waters 0 70842 0 72193 are related to chemical composition sr content and host rocks for vc 1 core samples the sr isotopic ratios are also markedly variable 0 70459 0 75686 low for the quaternary volcanics and high for the paleozoic sedimentary rocks the same observation is made for other jemez mountains rocks 0 70465 0 8163 with in addition high 87sr 86sr values for precambrian crystalline rocks a good correspondence is generally found between the waters and the reservoir rocks studied here which indicates that isotopic equilibrium is rapidly attained the following suite of hydraulically related fluids displays a progressive enrichment in radiogenic strontium baca wells 87sr 86sr 0 7084 0 7094 vc 1 core hole at 483 m 0 7152 0 7154 main jemez spring 0 7217 and soda dam 0 7219 this trend is associated with flow through paleozoic rocks and with the length of the flow path from the center of valles caldera primary geothermal fluids toward san diego canyon along the jemez fault zone derivative waters

diagenetic mass transport in the southern san joaquin basin california u s a implications from the strontium isotopic composition of modern pore fluids abstract three types of chemically and isotopically distinct pore fluids from the southern san joaquin basin previously recognized by j b fisher and j r boles also have distinctive 87 sr 86 sr ratios and sr concentrations meteoric fluids have stable isotopic compositions which lie on or near the meteoric water line and low chlorinities sr concentrations are between 0 01 and 2 6 mg l 1 and 87 sr 86 sr ratios range from 0 7061 to 0 7078 diagenetically modified connate marine fluids have d and 18o values more positive than 35 and 0 respectively and have chlorinities generally comparable to seawater sr concentration are much higher than the meteoric group 16 198 mg l 1 although the 87 sr 86 sr ratios 0 7070 0 7081 are not distinctive mixed meteoric modified connate fluids have d 18o and chlorinity intermediate between the meteoric and modified connate groups sr concentrations are also intermediate between 16 and 22 mg l 1 but 87 sr 86 sr ratios 0 7080 0 7087 are generally more radiogenic than either the meteoric or modified connate groups all of the fluids have 87 sr 86 sr ratios comparable to or lower than tertiary seawater alteration of detrital plagioclase is the probable origin of the low isotopic ratios mass balance calculations based on the sr data suggest that essentially no transport of sr occurred during diagenesis of sandstones containing modified connate pore fluids while large amounts of sr have been transported out of meteoric reservoirs by fluid flow the chemically anomalous mixed meteoric modified connate fluids contain the most radiogenic strontium in the basin these fluids are spatially associated with major faults and may represent clay mineral dehydration waters which have been transported upward from greater depth these results suggest that the three types of fluids identified by fisher and boles represent three distinct mass transport regimes a largely stagnant deep basin system containing modified connate pore fluids an actively recharging meteoric system along the basin flanks and a third system restricted to the southern basin which may be characterized by largescale cross formational fluid flow rather than dilution by meteoric waters

a geochemical and 3d geometry geophysical survey to assess artificial groundwater recharge potential in the pacific coast of baja california mexico a geophysical and geochemical study was carried out in the maneadero aquifer baja california mexico with the aim of identifying potential recharge locations for reclaimed water rw this coastal aquifer shows a significant decline in water quality both as a result of salinization and the pollution by nitrates total dissolved solids tds in an extreme case increased from 4 g l 1 in 2000 to 27 g l 1 in 2011 nitrate as n no3 reaches 46 mg l 1 based on their geochemistry and location four water quality zones are identified a fresh water with tds 1 g l 1 in the upper creeks b mixture between seawater and freshwater in the coast proximal sections c water significantly enriched in nitrate below and adjacent to the town of maneadero and d brackish water with no signs of current interaction with freshwater the 3d geophysics identifies the influence of modern recharge areas and also buried flow paths down to at least 30 m depth the locations best suitable for aquifer recharge are those with equal or higher tds concentrations 2 5 g l 1 than rw which are located at the brackish water zone and or at the coastal limits of the mixing zones

the neogene origin adoption evolution and controversy abstract some stratigraphers have recently insisted that for historical reasons the neogene miocene pliocene should be extended to the present however despite some ambiguity in its application by moriz hornes in the 1850s the neogene was widely adopted by european geologists to refer to the miocene and pliocene of lyell but excluding the diluvium later to become the pleistocene and alluvium later to become the holocene during the late 19th and early 20th centuries the ends of the neogene tertiary and pliocene evolved in response to the progressive lowering of the beginnings of the quaternary and pleistocene this evolution was a logical result of the widespread views that the most recent ice ages were worthy of recognition as a formal unit of the standard geologic time scale and that the structure of this time scale must be strictly hierarchical motivations for the extension of the neogene to the present include the desire to establish a monopoly for marine biochronology in the definition of standard global chronostratigraphic boundaries this agenda would also eliminate the tertiary quaternary and holocene these changes are unnecessary there is every reason to retain the traditional hierarchical structure of the cenozoic time scale

what is suspended sediment suspended sediment is conventionally regarded as that sediment transported by a fluid that it is fine enough for turbulent eddies to outweigh settling of the particles through the fluid early work in the fluvial field attributed suspension to turbulence and led to the notion of a critical threshold for maintaining sediment in suspension however research on both turbulence structures and the interactions between suspended sediment and bedforms in rivers has shown a more complex story and although there appear to have been no studies of the impact of bedforms on aeolian suspended sediment concentrations turbulent flow structures and transport rates of saltating particles have been shown to be affected this research indicates that suspended sediment neither travels with the same velocity as the flow in which it is suspended nor is it likely to remain in suspension in perpetuity even under conditions of steady flow or in unsteady flow the where dimensionless critical threshold is permanently exceeded rather like bedload it travels in a series of hops and is repeatedly deposited on the bed where it remains until it is re entrained is there therefore a qualitative difference between suspended and saltating sediment or is it just a quantitative difference in the size of the jump length and the frequency of re entrainment it is our contention that the distinction of suspension as a separate class of sediment transport is both arbitrary and an unhelpful anthropocentric artefact if we recognize that sediment transport is a continuum and applies to any fluid medium rather than split into different processes based on arbitrary thresholds and fluids then recognizing the continuity will enable development of an holistic approach sediment transport and thus sediment transport models that are likely to be viable across a wider range of conditions than hitherto this article is protected by copyright all rights reserved

comparison of settling velocity based formulas for threshold of sediment motion the critical condition for incipient sediment motion is formulated in this note based on the settling velocity the formula obtained is simple relating the ratio of critical shear velocity to settling velocity to the dimensionless sediment diameter comparisons are then made with other settling velocity based formulas available in the literature to facilitate the computation of the effective near bed velocity at the threshold condition a generalized law of the wall function is proposed for predicting the velocity distribution under various boundary conditions this study demonstrates that the settling velocity is equivalent to the critical near bed velocity which is experienced by a typical bed sediment particle under the threshold condition but only for large sediment sizes such as sand and gravel comparison results show that yang s formula is suitable for flows with small flow depth relative to sediment size while le roux s formula may overestimate the threshold condition for fine particles by up

paleozoic fluid history of the michigan basin evidence from dolomite geochemistry in the middle ordovician st peter sandstone abstract the isotope sr and o and elemental mg ca mn fe and sr compositions of the various dolomites in the middle ordovician st peter sandstone in the michigan basin are determined and the variations are modeled in terms of fluid rock interaction or as mixing relations these geochemical models combined with the paragenetic sequence of the dolomites and late anhydrite cement suggest the existence of at least four distinct diagenetic fluids in the st peter sandstone during the paleozoic fluid 1 sr 30 10 ppm sr ca 0 019 87sr 86sr 0 7093 1 has a composition consistent with a modified older pre middle ordovician seawater origin which indicates that the flow path for this fluid had a major upward component this fluid resulted in th first and volumetrically most important burial dolomitization event producing dolomite in both carbonate and quartz sandstone lithofacies in the st peter sandstone fluid 2 sr 30 10 ppm sr ca 0 019 87sr 86sr 0 7084 1 low fe has a composition consistent with a modified middle to early late ordovician seawater origin suggesting a major downward component for fluid flow fluid 2 produced dolomite cement in the carbonate lithofacies that postdates fluid 1 dolomite the composition of fluid 3 sr 50 ppm sr ca 0 044 0 110 87sr 86sr 0 710 0 711 high fe is best interpreted to reflect a heated deep basinal brine that had previously interacted with the k feldspar rich rocks near the cambrian precambrian unco formity in the michigan basin indicating a major upward component for fluid flow fluid 3 produced dolomite cement in quartz sandstone lithofacies that postdates fluid 1 dolomite fluid 4 87sr 86sr 0 7085 1 resulted in precipitation of late anhydrite in fractures the 87sr 86sr ratio of the anhydrite is consistent with fluid 4 originating as a dilute fluid that interacted extensively with silurian gypsum in the michigan basin this indicates that the flow path of fluid 4 had a major downward component the st peter sandstone was an important migration pathway for many different types of fluids in the michigan basin and the proposed fluid origins indicate that both upward and downward cross formational fluid flow occurred during the paleozoic older and younger modified seawater produced most of the burial dolomite in the st peter sandstone

carbon and oxygen isotopic composition of carbonates from saliferous deposits of the pripyat trough belarus abstract 18o and 13c in accessory calcite and dolomite from salt rock and in intrasalt carbonate beds of the upper frasnian and upper famennian evaporite formations of the pripyat trough vary over a wide range within all the intrasalt carbonate interbeds four distinct groups of rocks have been recognised on the basis of their isotopic composition the ranges of variation of 13c pdb and 18o smow within these groups are respectively a 0 7 to 0 8 and 35 4 to 36 4 b 4 5 to 0 9 and 30 0 to 32 2 c 7 0 to 2 8 and 19 8 to 25 5 d 17 5 to 9 7 and 20 9 to 26 4 the isotopic composition of accessory carbonates is more uniform the main body of values falls within the range 11 to 3 for 13c and 18 to 25 for 18o the carbonate matter with the observed combinations of 13c and 18o could have been formed during sedimentation and diagenesis in sabkhas on subaetially exposed islands on evaporite depression slopes washed by sea water and freshwater and in stagnant zones with hot brines the carbon isotopic composition of intrasalt carbonate rocks is on the average lighter than that of accessory carbonates from the salts this shows that the organic matter was most readily accumulated in evaporite basins during non salt sedimentation

charles lyell and the evidences of the antiquity of man abstract this paper examines the importance of lyell s book the geological evidences of the antiquity of man 1863 in lyell s work and career as well as its contribution to the founding of two scientific disciplines prehistoric archaeology and palaeoanthropology it first focuses on lyell s two conversions to the idea of the antiquity of man and to darwin s theory of transmutation of species both of which he acknowledged in his book it turns then to a study of the nature of the evidences that lyell advances these evidences were of several kinds archaeological palaeontological anthropological and most importantly geological at the time the best way to prove the existence of fossil man was to demonstrate geologically the contemporaneity of man made objects and extinct animals this paper insists in particular on lyell s relationship to french science of the time and examines the circumstances and modalities of a collaboration which was essential to the international acceptance of the antiquity of man the fact that lyell was a major scientific authority whose expertise could validate the authenticity of evidence allowed him to play a central role in the founding of a new field of knowledge

sediment transport and resulting deposition in spawning gravels north coastal california incubating salmonid eggs in streambeds are often threatened by deposition of fine sediment within the gravel to relate sedimentation of spawning gravel beds to sediment transport infiltration of fine sediment 2 mm in diameter into clean gravel beds bed material size distributions scour fill depths and sediment transport during 10 storm flow events were measured in three streams of north coastal california although suspended sediment comprised most 75 94 of the clastic load during storm flows bed load material 0 25 2 mm accounted for most 70 78 of the fine sediment accumulated in experimental gravel implanted in the streambeds sand trapped in the interstices of the top several centimeters formed a seal that impeded deeper deposition of very fine sand and finer material the seal was responsible at least in part for a decrease in the rate of fine sediment accumulation with increasing cumulative bed load transport areas of the streambeds commonly scoured or filled 0 1 m or more during storm flows and thus scour and fill commonly created a sandy layer at least as thick as the seal formed by sediment infiltration scour could erode eggs laid in the bed and expose deeper levels of the bed to infiltration by fine sediment but at the same time could allow fine sediment to be winnowed away great temporal and spatial variation in sedimentation in these streams suggests that individual storms of moderate size pose a threat to eggs in many but not all areas selected by fish for spawning

virtual velocity of tracers in a gravel bed river using size based competence duration virtual velocity vi of river gravels is commonly used to determine sediment transport rates and gravel dispersion dynamics virtual velocity is calculated from tracer gravel step length data as the distance travelled divided by the duration of competence however no allowance is usually made for differences in competence duration according to grain size in this investigation vi of gravel tracer clasts for the river rede northumberland uk is calculated using a method that takes into consideration an approximation of size based competence duration although scaled transport distance data compared favourably to past studies it was the comparatively smaller clasts that tended to have lower vi in comparison to coarser clasts because of their longer competence duration contrasting with previously published research the key findings of the study serve as proof of concept and should be adopted in future studies that focus upon vi estimation

measuring gravel transport and dispersion in a mountain river using passive radio tracers random walk models of fluvial sediment transport recognize that grains move intermittently with short duration steps separated by rests that are comparatively long these models are built upon the probability distributions of the step length and the resting time motivated by these models tracer experiments have attempted to measure directly the steps and rests of sediment grains in natural streams this paper describes results from a large tracer experiment designed to test stochastic transport models we used passive integrated transponder pit tags to label 893 coarse gravel clasts and placed them in halfmoon creek a small alpine stream near leadville colorado usa the pit tags allow us to locate and identify tracers without picking them up or digging them out of the streambed they also enable us to find a very high percentage of our rocks 98 after three years and 96 after the fourth year we use the annual tracer displacement to test two stochastic transport models the einstein hubbell sayre ehs model and the yang sayre gamma exponential model gem we find that the gem is a better fit to the observations particularly for slower moving tracers and suggest that the strength of the gem is that the gamma distribution of step lengths approximates a compound poisson distribution published in 2012 this article is a us government work and is in the public domain in the usa

multistage hydrothermal dolomites in the middle devonian givetian carbonates from the guilin area south china pervasive dolomites occur preferentially in the stromatoporoid biostromal or reefal facies in the basal devonian givetian carbonate rocks in the guilin area south china the amount of dolomites however decreases sharply in the overlying frasnian carbonate rocks dolostones are dominated by replacement dolomites with minor dolomite cements replacement dolomites include 1 fine to medium planar e floating dolomite rhombs rd1 2 medium to coarse planar s patchy mosaic dolomites rd2 and 3 medium to very coarse nonplanar anhedral mosaic dolomites rd3 they post date early submarine cements and overlap with stylolites two types of dolomite cements were identified planar coarse euhedral dolomite cements cd1 and non planar saddle dolomite cements cd2 they post date replacement dolomites and predate late stage calcite cements that line mouldic vugs and fractures the replacementdolomiteshaved 18 ovalues from 13ae7to 9ae7 vpdb d 13 cvalues from 2ae 7t o 1 ae5 vpdb and 87 sr 86 sr ratios from 0ae7082 to 0ae7114 fluid inclusiondataofrd3dolomitesyieldhomogenizationtemperatures th of136 149 c and salinities of 7ae2 11ae2 wt nacl equivalent these data suggest that the replacive dolomitization could have occurred from slightly modified sea water and or saline basinal fluids at relatively high temperatures probably relatedtohydrothermalactivitiesduringthelatestgivetian middlefammenian and early carboniferous times compared with replacement dolomites cd2 cements yield lowerd 18 o values 14ae2to 9ae3 vpdb lowerd 13 c values 3ae0 to 0ae7 vpdb higher 87 sr 86 sr ratios 0ae7100 and higher th values 171 209 c whichcorrespondtotrappingtemperatures tr between260and300 c after pressure corrections these data suggest that the dolomite cements precipitated from higher temperature hydrothermal fluids derived from underlying siliciclastic deposits and were associated with more intense hydrothermal events during permian early triassic time when the host dolostones were deeply buried the petrographic similarities between some replacement dolomites and cd2 dolomite cements and the partial overlap in 87 sr 86 sr and d 18 o values suggest neomorphism of early formed replacement dolomites that were exposed to later dolomitizing fluids however the dolomitization was finally stopped through invasion of meteoric water as a result of basin uplift induced by the indosinian orogeny from the early middle triassic as indicated by the decrease in salinities in the dolomite cements in veins 5ae1 0ae4 wt nacl equivalent calcite cements generally yield the lowest d 18 ovalues 18ae5to 14ae3 vpdb variabled 13 cvalues 11ae3to 1ae2 vpdb andhighthvalues 145 170 c andlowsalinities 0 0ae2wt naclequivalent indicating an origin of high temperature dilute fluids recharged by meteoric water in the course of basin uplift during the indosinian orogeny faults were

strontium isotopic evolution of oil field waters from carbonate reservoir rocks in bindley field central kansas u s a abstract oil field waters produced from mississippian carbonate reservoir rocks in bindley field kansas had an average salinity of about 42 8 mg l they were enriched in ca sr na k rb and li and depleted in mg relative to sea water at the same level of either cl or br concentration the average abundances of different elements are as follows na 13 460 mg l k 325 mg 1 rb 0 9 mg l li 12 mg l ca 1 515 mg l sr 42 mg l mg 430 mg l cl 23 000 mg l so4 2 630 mg l br 32 mg l the 87 sr 86 sr values of the waters ranged between 0 7221 and 0 7230 whereas the values of the host carbonate rocks were between 0 7090 and 0 7093 the very high 87 sr 86 sr values of the waters probably occurred as a result of their reaction with alkali feldspar minerals in buried precambrian crystalline rocks to the east of the bindley field the study demonstrates that despite their residence in carbonate reservoir rocks oil field waters can retain sufficiently distinct isotopic memory that may provide important dues about mineral water interactions in the chemical evolutionary history of the waters the study further indicates that very late diagenetic reactions in many carbonate rocks are of minor extent difference in the sr isotopic data among the oil field waters suggests that the sr isotopic data can be used as a reliable guide in recognising existence of separate pools in an oil field

tracer pebble movement along a concave river profile virtual velocity in relation to grain size and shear stress over 1400 tracer pebbles 16 256 mm in diameter were tracked for 2 years in six reaches of allt dubhaig scotland a small gravel bed river along which shear stress and bed surface grain size decrease toward a local base level pebble movement was size selective both within and between reaches within reaches the decrease in mean travel distance with increasing grain size is strongest in the coarse tail of the size distribution particle shape has a minor secondary effect a nondimensional grain velocity averaged over the duration of competent flow is used to compare different size classes and reaches over 90 of its variance is explained by relative grain size and reach shields stress the pattern of size selectivity is consistent with single event tracer results elsewhere bedload trap data from our distal reach and the concept of partial mobility it provides a mechanism for strong downstream fining by selective transport and deposition along rivers in which stress declines toward base level the nondimensional prediction equation for grain velocity may be of use in other rivers but requires testing