a 160 k y old record of el nino southern oscillation in marine production and coastal runoff from santa barbara basin california usa a 160 k y old laminated sediment record from the santa barbara basin california analyzed using scanning electron microscope techniques provides a history of interannual variability of marine production and coastal runoff we used backscatter electron imagery to measure the components of the varve these include a terrigenous lamina formed by seasonal runoff from winter rains together with a diatomaceous lamina that records marine production during the spring and early summer spectral analysis of terrigenous and diatomaceous laminae thickness reveals significant periodicities of 3 1 and 8 4 yr in the terrigenous series these are indistinguishable within the frequency resolution of the spectra from significant periodicities of 3 5 and 7 6 yr in the diatomaceous series the 3 1 and 3 5 yr periodicities record el nino modulation of coastal runoff and marine production the 8 4 and 7 6 yr periodicities are consistent with modulation by strong to very strong el nino events this is supported by the results of cross spectral analysis of the terrigenous and diatomaceous records which reveal inverse or antiphase relationships at 3 5 and 7 6 yr our work adds to a body of evidence that suggests that el nino has been a persistent feature of late quaternary climate variability

dynamic elastic properties of coal laboratory ultrasonic velocity measurements of different types of coal demonstrate that their dynamic elastic properties depend on coal rank and applied effective pressure in spite of the growing interest in coal beds as targets for methane production the high abundance in sedimentary sequences and the strong influence that they have on seismic response little data are available on the acoustic properties of coal velocitiesweremeasuredincoreplugsparallelandperpendicular to lamination surfaces as a function of confining pressure up to 40 mpa in loading and unloading cycles pand s wave velocities and dry bulk and dry shear moduli increaseascoalrankincreases thus bituminouscoalandcannel show lower velocities and moduli than higher ranked coals such as semianthracite and anthracite the vp vs relationshipfordrysamplesislinearandcoversarelativelywide rangeofeffectivepressuresandcoalranks however thereis a pressure dependence on the elastic properties of coal for confiningpressuresbelow5 mpa thispressuresensitivityis relatedtothepresenceofmicrocracks finally thedatashow that coal has an intrinsic anisotropy at confining pressures above 5 mpa the closing pressure for most of the microcracks this intrinsic anisotropy at high pressures might be due to fine lamination and preferred orientation of the macerals

an 15 000 year record of el nino driven alluviation in southwestern ecuador debris flows have deposited inorganic laminae in an alpine lake that is 75 kilometers east of the pacific ocean in ecuador these storm induced events were dated by radiocarbon and the age of laminae that are less than 200 years old matches the historic record of el nino events from about 15 000 to about 7000 calendar years before the present the periodicity of clastic deposition is greater than or equal to 15 years thereafter there is a progressive increase in frequency to periodicities of 2 to 8 5 years this is the modern el nino periodicity which was established about 5000 calendar years before the present this may reflect the onset of a steeper zonal sea surface temperature gradient which was driven by enhanced trade winds

discussion of deglacial paleoclimate in the southwestern united states an abrupt 18 6 cold event and evidence for a north atlantic forcing of termination i by m s lachniet y asmerom and v polyak

biological forcing of hemipelagic sedimentary laminae evidence from odp site 893 santa barbara basin california core observation x radiography and scanning electron microanalysis of distinctly laminated indistinctly laminated and nonlaminated sediments from odp site 893 show that laminated as well as nonlaminated i e massive hemipelagic sediments can form in the absence of bioturbation this view contrasts with conventional sedimentological interpretations equating laminated hemipelagic sediments with anoxic water masses i e absence of bioturbation and nonlaminated sedimentary intervals exclusively with oxygenation episodes that permitted infaunal colonization we conclude that heterogeneities in the texture and or composition of sediment supply are necessary for the production of laminated sediments the absence of hydraulic and biological reworking permits their preservation laminae at site 893 have two prominent components biosilica and terrigenous detritus compositional contrasts between adjacent laminae in x radiographs reflect short term seasonal and subseasonal heterogeneities in sediment flux core intervals with large contrasts in density and or composition between adjacent laminae are termed as having high bimodality hb hb couplets produce distinctly laminated sediments that intergrade vertically with indistinctly laminated and nonlaminated sediments adjacent laminae in indistinctly laminated sediments possess minimal contrasts in bulk density and composition nonlaminated sediments are compositionally and texturally homogeneous many biosiliceous laminae responsible for distinctly laminated hb couplets record mass flocculation and sedimentation of ungrazed diatom frustules formed during discrete bloom events ecological interpretation of diatomite laminae suggests that many were effectively self sedimenting i e the production of gelatinous exudates by phytoplankton facilitated their aggregation and rapid sedimentation the results indicate that lamination style preserves meaningful ocean climate data concerning episodicity heterogeneity and export efficiency of biologically mediated sedimentary flux in upwelling dominated coastal ecosystems

devils hole nevada δ18o record extended to the mid holocene abstract the mid to late pleistocene devils hole 18 o record has been extended from 60 000 to 4500 yr ago the new 18 o time series in conjunction with the one previously published is shown to be a proxy of pacific ocean sea surface temperature sst off the coast of california during marine oxygen isotope stages mis 2 and 6 the devil hole and sst time series exhibit a steady warming that began 5000 to 10 000 yr prior to the last and penultimate deglaciations several possible proximate causes for this early warming are evaluated the magnitude of the peak 18 o or sst during the last interglacial lig is significantly greater 1 per mill and 2 to 3 c respectively than the peak value of these parameters for the holocene in contrast benthic 18 o records of ice volume show only a few tenths per mill difference in the peak value for these interglacials statistical analysis provides an estimate of the large shared information variation between the devils hole and eastern pacific sst time series from 41 to 2 n and enforces the concept of a common forcing among all of these records the extended devils hole record adds to evidence of the importance of uplands bordering the eastern pacific as a source of archives for reconstructing pacific climate variability

the influence of tectonic deformation on some geochemical properties of coals a possible indicator of outburst potential abstract nearly all outburst prone coal is known to have been tectonically deformed in fault and fold zones which underwent one or more episodes of strong structural deformation the physical properties of deformed coal such as strength coefficient and rate of gas desorption have been broadly studied and used to predict outbursts in the past however it can be difficult to reliably determine these physical coefficients from core sampling operations because the coal can be inadvertently pulverized during drilling the development of a new index which predicts the outburst potential of coal seams and is not influenced by sampling procedures could be beneficial to mining safety technology tectonic deformation may not only affect the original physical structure of a coal but also may bring about changes in chemical properties any chemical property with the potential to identify outburst prone coal must also be stable and independent of the physical changes imposed by drilling most of the chemical characteristics of coal display no obvious difference between normal undeformed coal which is not subject to outbursts and deformed coal however recent studies have shown that the chloroform extract yield is a very good geochemical index for differentiating these coals nineteen coal samples from five mines experiencing outbursts in the pingdingshan coalfield henan china were analyzed their mean maximum vitrinite reflectance in oil ranges from 0 97 to 1 28 all of the samples were prepared to 180 m 80 mesh us and subsamples were extensively extracted with chloroform in a soxhlet apparatus at 75 c the mean extract yield of the 10 deformed coals is 1 45 whereas that of the nine normal coals is 0 44 we conclude that deformed coal has a higher chloroform extract yield than equivalent coal which has not been tectonically disturbed chloroform extraction therefore can be used to recognize deformed coal and the potential to undergo further deformation chloroform extract yield is an accepted measure of the hydrocarbon generating potential of coals and other rocks the results presented here therefore suggest that tectonic deformation may modify the hydrocarbon generating potential of coals the adsorption of soluble organic matter expelled during and following tectonic deformation onto enhanced surface areas may have contributed to the higher extract yields of the deformed coal

surface ocean variability at galapagos from 1936 1982 calibration of geochemical tracers in corals a variety of geochemical tracers has been developed in reef corals as a means of reconstructing the natural variability of the tropical surface ocean over wide ranging time frames the purpose of this paper is to calibrate the performance of five of these tracers in a modern coral colony over an extended period a 47 year growth interval 1936 1982 in a colony of pavona clavus taken from san cristobal island galapagos islands was sectioned into 187 quarterly intervals and analyzed for 18o 13o ba ca cd ca and mn ca the resulting time series are compared with eastern pacific sea surface temperatures one of few instrumental data bases available for calibration over this time period linear least squares regressions of four of the tracers 18o 13o ba ca cd ca against peruvian sst show highly significant correlations p 0 0001 over the annual biennial and enso 3 8 years frequency bands cross spectral comparisons show even stronger coherency with sst frequently accounting for 70 80 of the variance in these tracers these results as well as the phase relationships determined from the spectral analyses suggest that the coupling between sst and 18o and the nutrientlike tracers ba and cd is controlled principally by seasonal upwelling cycles and interannual interruptions of these cycles brought about by el nino and anti el nino phenomena an inverse relationship between sst and 13c has its primary origins in the co occurrence of the warm sst phase with high light levels during the first half of the calendar year the association with sunlight derives from the photosynthetic response of algal symbionts which results in fractionation of light and heavy carbon isotopes between soft tissues and caco3 skeleton the fifth tracer the transition metal mn exhibits poorer correlations against both sst and the other tracers slight shifts in phasing of the historical mn ca annual cycle suggest that the general water column distribution of this tracer which is the reverse of a nutrient may not be stable the erratic behavior of mn illustrates how complex hydrography near galapagos may influence tracers with diverse source signatures

predicting stress induced velocity anisotropy in rocks a simple transformation using measured isotropic vp and vs versus hydrostatic pressure is presented for predicting stress induced seismic velocity anisotropy in rocks the compliant crack like portions of the pore space are characterized by generalized compressional and shear compliances that are estimated from the isotropic vp and vs the physical assumption that the compliant porosity is crack like means that the pressure dependence of the generalized compliances is governed primarily by normal tractions resolved across cracks and defects this allows the measured pressure dependence to be mapped from the hydrostatic stress state to any applied nonhydrostatic stress predicted p and s wave velocities agree reasonably well with uniaxial stress data for barre granite and massillon sandstone while it is mechanically similar to methods based on idealized ellipsoidal cracks the approach is relatively independent of any assumed crack geometry and is not limited to small crack densities

reconstructing mid to high latitude marine climate and ocean variability using bivalves coralline algae and marine sediment cores from the northern hemisphere quantifying the role and contribution of the world s oceans in past present and future global change is an essential goal in climate paleoclimate and environmental studies although the global oceans interact and influence climate greatly the marine environment is substantially under represented in key climate assessment reports especially during the last millennium ipcc 2007 see palaeoclimate chapter 6 6 the last 2000 years the under representation of marine records in key climate documents likely results from the often imprecise chronologies associated with many marine based archives which greatly hinders singular climate comparisons lag lead phasing relationships with well dated and or annually resolved archives however several marine archive records have excellent chronological constraint in particular many marine bivalve taxa and coralline algae have annual increments that form within their carbonate framework that can be used to establish an absolutely dated chronology via cross dating techniques from the marine environment additionally in some cases where sedimentation rates are high and alternative chronological dating methods exist e g tephrochronology other than radiocarbon measurements often greater than 40 years uncertainty sediment archives can provide continuous sub decadal records of environmental change for centuries to millennia this brief introductory article and accompanying special issue will focus on the utilization of bivalves coralline algae and high resolution marine sediment cores in paleoclimate and environmental studies within the most recent millennium with a focus on the northern hemisphere

el nino during the last interglacial period recorded by a fossil coral from indonesia measurements of oxygen isotopes and elemental ratios in a fossil coral that grew 124 000 years ago in north sulawesi indonesia reflect interannual variability in precipitation and sea surface temperature sst due to the el nino southern oscillation enso this indicates that enso was robust during the last interglacial period a time when global climate was slightly warmer than the present the pattern of enso frequency behavior in the past is similar to variability in modern instrumental records but distinct from the most recent period since the mid 1970s supporting the hypothesis that enso behavior in recent decades is anomalous with respect to natural variability

rare earth element geochemistry of laminated diatom mats from tropical west pacific evidence for more reducing bottomwaters and higher primary productivity during the last glacial maximum rare earth elements ree along with selected major and trace elements were measured in laminated ethmodiscus rex diatom mats and associated sediments diatomaceous clay and pelagic clay in two sediment cores collected from the parece vela basin of the eastern philippine sea ree distributions are characterized by strong enrichment of middle ree mree and heavy ree hree over light ree lree and slight enrichment of mree over hree this distribution pattern suggests that ree compositions of the laminated e rex diatom mats were not the product of e rex blooms an inference also supported by the fact that ti normalized ree concentrations are not clearly different from those in the diatomaceous clay and pelagic clay comparison of ree patterns with the vertical distribution of authigenic phases in the sediment indicates that lree were dominantly associated with detrital materials whereas mree and hree were selectively enriched by mn oxyhydroxides and authigenic phosphates in the pelagic clay a weak negative ce anomaly cannot be linked to oxic depositional conditions but instead is attributed to the retention of a negative ce anomaly associated with authigenic phosphates in the laminated e rex diatom mats a weak positive ce anomaly is consistent with depositional sulfidic anoxic conditions and is interpreted to represent enhanced scavenging of reduced aqueous ce3 by barite in a strongly reducing environment moreover variably negative to positive ce anomalies in the diatomaceous clay may reflect the concurrent operation of the two processes controlling ce accumulation in the laminated e rex diatom mats and pelagic clay the study cores show a ubiquitous positive eu anomaly owing to the presence of volcanic materials the smaller eu anomaly in the laminated e rex diatom mats and diatomaceous clay relative to that in the pelagic clay may be attributed to the release of reduced eu2 from mineral phases to the sediment pore water under strongly reducing conditions previous studies have shown that the advection of lower circumpolar water lcpw strengthened during the last glacial maximum lgm which should have resulted in better ventilation of the deep eastern philippine sea evidence presented here for more reducing bottomwater conditions during the laminated e rex diatom mats formation implicates elevated primary productivity and enhanced organic sinking fluxes as primary controls on redox changes in the eastern philippine sea during the lgm enhanced primary productivity and more reducing bottomwaters during the laminated e rex diatom mats deposition resulted in a larger respired carbon pool in the deep eastern philippine sea which may have been part of a larger scale modulation of atmospheric co2 variation during pleistocene glacial interglacial cycles by deep ocean carbon storage c 2011 elsevier b v all rights reserved

low frequency changes in el nino southern oscillation abstract although there are indications from numerical models that el nino southern oscillation enso may be an internal mode of the coupled pacific ocean atmosphere system sensitive to climatic background parameters it has not yet been possible to find significant changes in enso variability between the little ice age and the present yet a number of authors have found qualitative indications in anecdotal and proxy records of shorter century scale variations in the return interval statistics for el nino episodes to objectively determine what nonstationarities exist we statistically examine the el nino occurrences since 1525 compiled by quinn et al we have stratified the return intervals both for strong events and for all events according to two null hypotheses 1 return intervals are stationary over periods of 200 500 years and 2 the intervals are stationary on a centenary time scale between epochs of contrasting solar variability two parameter weibull distributions are fit to subsamples of

brief interstadial events in the santa barbara basin ne pacific during the past 60 kyr the instability of the northern hemisphere glacial climate over the past 100 kyr has been revealed by at least 20 brief warm interstadial episodes called dansgaard oeschger events recorded in greenland ice cores1 3 and in north atlantic sedimentary records4 5 a few of these events have been recognized elsewhere6 8 here we describe a record of ocean oxygenation and circulation from the santa barbara basin in the northeast pacific ocean which correlates well with the greenland ice core records we see 19 of the 20 dansgaard oeschger events in the form of laminated sediments deposited under anoxic conditions and we can correlate at least 16 of these with the 17 ice core interstadials of the past 60 kyr thus these short term events were not restricted to the north atlantic region the events had substantial ecological and oceanographic effects in the santa barbara basin including changes in benthic faunal populations and in the age and composition of bottom waters similar ventilation changes have been seen in the gulf of california9 10 suggesting that these changes may have been widespread and synchronous along the northeast pacific margin these results suggest sensitivity of broad areas of the ocean atmosphere cryosphere system to short term climate change

particulate metal speciation in surficial sediments from loch dee southwest scotland u k the geochemical partitioning of ten elements in stratified holocene sediments from loch dee southwest scotland has been established by use of a five stage sequential extraction procedure samples from below 15 cm sediment depth show minimal evidence of modification by anthropogenic contamination or active diagenesis and hold fe mg cu cd co pb and ni primarily in detrital silicates or organic complexes while mn ca and zn reside largely in adsorbed and reducible oxide phases in the uppermost ca 15 cm of sediment enhanced total concentrations of zn cu and pb reflect increased atmospheric deposition during the postindustrial period of these metals only pb displays any notable adjustment of partitioning in the enriched zone showing disproportionate accumulation in labile oxides and organic pb phases the lack of pb and zn carbonates in the contaminated horizon may reflect inherent thermodynamic instability under the acid surface and pore water conditions of loch dee increments to total mn and co in the surficial ca 5 cm of sediment are attributable to the accumulation of secondary oxides and adsorbed species consistent with precipitation from the interstitial pore waters across a sedimentary redox front the presence of metals such as zn and cd in soluble or acid volatile phases in the interfacial sediment has implications for the future management of the loch dee basin with leaching into the overlying waters likely given the continuation of current trends of lake acidification

southern ocean laminated diatom ooze mat deposits and potential for palaeo flux studies odp leg 177 site 1093 laminated diatom ooze samples collected during odp leg 177 were analysed using scanning electron microscope sem and optical microscopy to test their potential as high resolution records of polar front hydrography surface production and export sem analysis from two intervals marine isotope stage mis 29 and 12 11 respectively recovered from 50 s in the atlantic ocean odp site 1093 hole a sections 13h 4 0 18 cm and 23h 4 0 22 cm show abundant and well preserved thalassiothrix antarctica mats thought to be indicative of rapid export from the surface and deposition in the sediment a preliminary analysis of laminae succession points to a possible annual couplet triplet succession of laminae and suggests exceptionally high local sedimentation rates of 57 and 80 cm kyr 1 for mis 12 11 and 29 respectively such high accumulation rates imply that local export from the surface layer and sequestration of biogenic silica and organic matter to the sediments may have been much higher than previously suggested resume des depot sedimentaires lamines de diatomites recueillis pendant le leg 177 de l ocean drilling program odp ont ete analyses en microscopie electronique a balayage sem et en microscopie optique ces enregistrements sedimentaires presentent un fort potentiel pour reconstituer avec une haute resolution la production de matiere exportee depuis la couche de surface de l ocean au niveau du front polaire l analyse en sem des stades isotopiques 29 et 12 11 sur du materiel collecte a 50 s dans le secteur atlantique de l ocean austral site odp 1093 forage a sections 13h 4 0 18 cm et 23h 0 22 cm revele des depots abondants et bien preserves de tapis de thalassiothrix antarctica suggerant une exportation rapide jusqu au sediment de materiel biogene genere a la surface de l ocean une analyse preliminaire des successions laminees par couple ou triplet indique des vitesses d accumulation sedimentaire exceptionnellement elevees 57 et 80 cm kan 1 respectivement pour les stades 12 11 et 29 de telles vitesses d accumulation suggerent que l exportation de matiere depuis la couche de surface de l ocean et ou la preservation de silice biogene dans le sediment peuvent etre bien plus elevees qu on ne le pensait jusqu a present

evidence for abrupt climate changes in annually laminated marine sediments annually laminated sediments from marine or lacustrine settings represent valuable high resolution archives of climate change that record variation due to changing precipitation and run off from land or variation in biological productivity and flux in the water column because of their annual resolution such sediments may capture abrupt changes of interannual to decadal scales rivaling corals and ice cores in resolution laminated sediments often occur intermittently in the sediment column and the onset and cessation of laminae commonly record the abrupt crossing of thresholds related to climate change for example in the degree of oxygenation of bottom waters such records from marginal basins and continental margins have been pivotal in demonstrating that abrupt changes hitherto documented only in high latitude ice cores are synchronous with climatic change at low latitudes these insights into global teleconnections have improved our understanding of the mechanisms of rapid climate change in deep sea settings the discovery of the episodic occurrence of laminated diatom rich sediments in the equatorial pacific and southern ocean provides evidence for massive climate related biogeochemical excursions tied to abrupt changes in the input distribution and availability of nutrients in the oceans

mechanisms controlling cu fe mn and co profiles in peat of the filson creek fen northeastern minnesota abstract filson creek fen located in northeastern minnesota overlies a cu ni sulfide deposit a site in the fen was studied to evaluate the hydrogeochemical mechanisms governing the development of fe mn co and cu profiles in the peat at the study site surface peat approximately 1 m thick is separated from the underlying mineralized bedrock by a 6 12 m thickness of lake and glaciofluvial sediments and till concentrations of fe mn co and cu in peat and major elements in pore water delineate a shallow relatively oxidized cu rich zone overlying a deeper reduced fe mn and co rich zone within the peat sequential metal extractions from peat samples reveal that 40 55 of the cu in the shallow zone is associated with organic material whereas the remaining cu is distributed between iron oxide sulfide and residual fractions sixty to seventy percent of the fe mn and co concentrated in the deeper zone occur in the residual phase the metal profiles and associations probably result from non steady state input of metals and detritus into the fen during formation of the peat column the enrichment of organic associated cu in the upper oxidized zone represents a combination of cu transported into the fen with detrital plant fragments and soluble cu derived from weathering of outcrop and subcrop of the mineral deposit transported into the fen and fixed onto organic matter in the peat the variable stratigraphy of the peat indicates that weathering processes and surface vegetation have changed through time in the fen the fe mn and co maxima at the base of the peat are associated with a maximum in detrital matter content of the peat resulting from a transition between the underlying inorganic sedimentary environment to an organic sedimentary environment the chemistry of sediments and ground water collected beneath the peat indicate that mobilization of metals from sulfide minerals in the buried mineral deposit or glacial deposits is minimal therefore the primary source of cu to the peat at the study site is outcrops and shallow subcrops of the mineral deposit adjacent to the fen

expression of seasonal and enso forcing in climatic variability at lower than enso frequencies evidence from pleistocene marine varves off california abstract upper pleistocene marine sediments along the upper continental slope off northern and central california contain alternations of varved and bioturbated sediments and associated changes in biota and sediment composition these alternations can be related to conditions that accompany el nino and anti el nino enso circulation anti el nino conditions are characterized by increased upwelling and productivity and by low concentrations of dissolved oxygen in the oxygen minimum zone that resulted in varve preservation el nino conditions are characterized by little or no upwelling low productivity and higher concentrations of dissolved oxygen that resulted in zones of bioturbation alternations of varves and zones of bioturbation that range from decades to millennia occur through the upper pleistocene section the inferred long term alternations in el nino and anti el nino conditions appear to be a re expression of enso s primary 3 7 year cycle decadal to millennial cycles of productivity associated with el nino and anti el nino conditions may have served as a carbon pump and transferred atmospheric co 2 to the marine reservoir changes in sediment composition and organisms associated with el nino or anti el nino conditions can be related to both seasonal and enso phenomena expression of these changes at lower than enso frequencies may be partly explained by adding the effects of seasonal variability to effects produced by a self oscillating enso system however deterministic mechanisms including solar modulation of enso may also contribute to long term alternations of el nino and anti el nino conditions

el nino southern oscillation variability from the late cretaceous marca shale of california changes in the possible behavior of el nino southern oscillation enso with global warming have provoked interest in records of enso from past greenhouse climate states the latest cretaceous laminated marca shale of california permits a seasonal scale reconstruction of water column flux events and hence interannual paleoclimate variability the annual flux cycle resembles that of the modern gulf of california with diatoms characteristic of spring upwelling blooms followed by silt and clay and is consistent with the existence of a paleo north american monsoon that brought input of terrigenous sediment during summer storms and precipitation runoff variation is also indicated in the extent of water column oxygenation by differences in lamina preservation time series analysis of interannual variability in terrigenous sediment and diatom flux and in the degree of bioturbation indicates strong periodicities in the quasi biennial 2 1 2 8 yr and low frequency 4 1 6 3 yr bands both characteristic of enso forcing as well as decadal frequencies this evidence for robust late cretaceous enso variability does not support the theory of a permanent el nino in the sense of a continual el nino like state in periods of warmer climate

solar variance recorded in lacustrine deposits from the devonian and proterozoic of scotland abstract continental lacustrine laminites deposited in low latitudes have been examined from the devonian and torridonian mesoproterozoic strata of northern scotland to investigate the consistency of sunspot periodicity through geological time the thicknesses of 2448 annual laminae were measured from the middle devonian c 388 ma achanarras limestone member lower caithness flagstone group and of 2821 laminae from the mesoproterozoic 1 2 ga poll a9mhuilt member of the stoer group time series analysis resolved periodicities of 13 8 and 13 9 years in the complete devonian and mesoproterozoic datasets respectively when sedimentological variance was considered and the data were examined as evolutive spectra those sections consisting of the most robust data consistently yielded periodicities between 8 6 and 13 7 years for the devonian section and 9 2 and 10 6 years for the mesoproterozoic section these correspond well to schwabe cycles evidence for the presence of the longer hale cycles 20 years was also recognized in the devonian time series the sunspot periodicities identified within the devonian and mesoproterozoic show little variance from published examples from the quaternary and eocene and therefore provide evidence for the consistency of solar processes and solar atmospheric interactions for the past 1 2 ga

precise timing of the last interglacial period from mass spectrometric determination of thorium 230 in corals the development of mass spectrometric techniques for determination of 230 th abundance has made it possible to reduce analytical errors in 238 u 234 u 230 th dating of corals even with very small samples samples of 6 x 10 8 atoms of 230 th can be measured to an accuracy of 3 percent 2 and 3 x 10 10 atoms of 230 th can be measured to an accuracy of 0 2 percent the time range over which useful age data on corals can be obtained now ranges from about 50 to about 500 000 years for young corals this approach may be preferable to 14 c dating the precision with which the age of a coral can now be determined should make it possible to critically test the milankovitch hypothesis concerning pleistocene climate fluctuations analyses of a number of corals that grew during the last interglacial period yield ages of 122 000 to 130 000 years the ages coincide with or slightly postdate the summer solar insolation high at 65 n latitude which occurred 128 000 years ago this supports the idea that changes in pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth s orbit and rotation axis

a 2100 year bp record of the pacific decadal oscillation el nino southern oscillation and quasi biennial oscillation in marine production and fluvial input from saanich inlet british columbia exceptional varved sediments of 2100 years bp recovered from saanich inlet have been analysed using high resolution scanning electron microscopy and spectral analysis techniques each varve may contain up to 22 well defined individual laminae which can be attributed to seasonal scale processes sediment flux comprises alternating diatom ooze diatomaceous mud deposited during spring through autumn and a silty clay deposited during winter the latter may be sporadically punctuated by clay rich laminae identification of some 2000 individual consecutive laminae based on fabric and diatom assemblage has allowed the construction of time series data for spectral analysis laminae types analysed include early spring thalassiosira spp late spring early summer skeletonema costatum multiple summer autumn chaetoceros spp diatom oozes and sporadically present clay rich winter flood deposits sub decadal periods have been identified and linked to the quasi biennial oscillation qbo and el nino southern oscillation enso and decadal periods to the pacific decadal oscillation pdo comparison of spectral analysis results with modern analogues suggests associations may exist between early spring thalassiosira spp laminae and stronger la nina events late spring early summer s costatum laminae and el nino events summer autumn chaetoceros spp multiple laminae and negative pacific northwest index pni regimes and sporadically present winter clay rich laminae and pni regimes the average period for an enso cycle was 3 6 years qbo 2 5 years and pdo 14 8 years spectral analysis of the more recent pni record shows similar significant periods of 13 2 3 7 and 2 6 years multi decadal periods recorded include 42 2 and 31 3 years which might suggest multiples of pdo

early holocene decadal scale ocean variability recorded in gulf of california laminated sediments scanning electron microscope examination of holocene laminated sediment from guaymas basin gulf of california resolves up to five depositional events per year each lamina sublamina of an early holocene section of continuously laminated sediment was recorded from backscattered electron imagery photomosaic analysis diatom mat laminae composed predominantly of thalassiothrix longissima are associated with early winter mixed diatom flora laminae mats are probably brought into the gulf with pacific water during the summer concentrated at the surface or at the pycnocline and then rapidly deposited in the early winter as water column stratification breaks down time series analysis of one 300 year section from piston core jpc56 revealed significant periodicities in the deposition of mat laminae at 50 years 11 years and 22 24 years an 50 year cycle in fish populations has been related to changing north pacific ocean atmosphere circulation these pacific wide changes in circulation affect the currents dominant at the mouth of the gulf when the california current is dominant fewer diatom mats are imported into the gulf and when the north equatorial pacific gyre is dominant more are imported the 11 year 22 to 24 year and 50 year cycles are all suggested to be influenced by solar cycles

paleoproductivity and paleoredox conditions during late pleistocene accumulation of laminated diatom mats in the tropical west pacific paleoproductivity and paleoredox conditions were reconstructed in a sediment core in the parece vela basin of the eastern philippine sea the core consists of three units from youngest to oldest 1 laminated diatom mats ldm formed by ethmodiscus rex during the last glacial maximum similar to 18 28 kyr b p 2 diatomaceous clay dc and 3 pelagic clay pc elevated levels of export productivity during ldm deposition are indicated by high values for excess ba opal content and toc ti ratios estimated rates of organic carbon degradation ca 98 opal mass accumulation average 1322 g m 2 yr 1 and corrected organic carbon flux average 248 g m 2 yr 1 are comparable to high productivity regions of the modem ocean the ldm is also characterized by moderate enrichment of redox sensitive elements such as u mo cd and zn highly s 34 depleted pyrite sulfur isotopic compositions indicating bacterial sulfate reduction in a sulfate unlimited system and c s fe systematics reflecting limitation of pyrite formation by organic matter rather than reactive fe availability these features suggest mainly suboxic conditions in bottom waters but development of sulfidic anoxic conditions at or close to the sediment water interface association of intensified anoxia with productivity maxima indicates that export production was a more important control on bottom water redox conditions than lateral ventilation the dc and pc accumulated under oxic to suboxic conditions our observations suggest that redox environments during deposition of laminated marine sediments are more complicated and varied than previously thought and thus the use of sediment lamination as an indicator of anoxic bottom water conditions must be approached cautiously c 2012 elsevier b v all rights reserved

pore structure of sheared coals and related coalbed methane coalbed methane is considered to be one of the major contributors to global warming geological prospecting of the rich storage zone of methane is an important precondition for gas recovery projects shear zones along coal seams have long been considered as a major place where gas outbursts occur during mining but they also have a positive aspect in coalbed methane prospecting and production because of their great quantity of fractures and high methane content mercury penetrating experiments on a series of variously sheared coal samples from the pingdingshan coalfield china were performed the results showed that tectonically sheared coals possess three to eight times more porosity and two to ten times more specific surface area than their normal counterparts moreover brittlely deformed coals possess larger average fracture apertures representing a good condition for methane extraction whereas ductilely deformed coals show a fracture aperture even smaller than normal coals which can explain why intensely sheared coals become difficult for methane extraction the occurrence of a large number of tectonic fractures in a shear zone will make it easier for an artificial fracture to increase the permeability of coals in methane production therefore except for locally ductile deformation areas shear zones along coal seams are the best source and reservoir for methane gas production and if this methane is extracted it will help not only the reservoir but also protect the earth against global warming

experimental study on ultrasonic velocity and anisotropy of tectonically deformed coal abstract tectonically deformed coal tdc is defined as coal formed by various tectonic stresses as one of the key concerns in the formation and recovery of coal bed methane cbm from the tectonic deformation coal seams the texture and fractures of tdc present various features in different deformation environments and as a result the physical properties change therefore the identification of tdc is significant and can be obtained from the physical properties in this study fourteen representative tdc and two undeformed coal samples from the suzhou mining area in the east of north china plate were collected to investigate the geophysical recognition parameters of tdc by elastic properties such as the velocities p and s waves elastic parameters v p v s and poisson s ratio and velocity anisotropies the results show that the elastic properties of undeformed coal and tdc samples from different deformation environments exhibit significant difference normally the velocities and elastic parameters of undeformed coal have the highest values while the velocity anisotropy has the lowest value in brittle deformation environment the velocity and elastic parameters decrease while the velocity anisotropy ascends with increased deformation extent for the tdc samples from shear deformation environment the velocity anisotropies present the significant high values among the selected tdc samples in plastic deformation environment the elastic parameters gradually decrease with the deformation extent ascending while the velocity anisotropies are relatively high among the elastic properties the v p v s poisson s ratio and velocity anisotropy are sensitive to deformation type and extent of coal samples furthermore the development characteristics of coal structural fractures have a significant impact on the elastic properties of measured coal samples from different deformation environments in summary the results may provide reference parameters for future studies in cbm rock physics from the tectonic deformation coal seams

varves in marine sediments a review the global compilation of reported marine varved sedimentary records throughout the quaternary contains 52 sites marine varve deposition and preservation typically depend on environmental and sedimentological conditions such as a sufficiently high sedimentation rate severe depletion of dissolved oxygen in bottom water to exclude bioturbation by macrobenthos and a seasonally varying sedimentary input to yield a recognizable rhythmic varve pattern additional oceanographic factors include the strength and depth range of the oxygen minimum zone omz and regional anthropogenic eutrophication from point sources such as large polluted rivers quaternary marine varves are not only found in those parts of the open ocean that comply with these conditions but also in fjords embayments and estuaries with thermohaline density stratification and nearshore marine lakes with strong hydrologic connections to ocean water this review critically describes settings and sedimentological characteristics of marine sites where varves have been reported broader applications of marine varve records are discussed for example in terms of radiocarbon calibration on high resolution time scales constraining paleoceanographic variability and global change teleconnections diagnosing factors affecting modern fish population dynamics based on past performance detailing biogeochemical cycles and deciphering complex factors influencing marine productivity varves in saline water bodies without hydrologic connection to the global ocean are not included in this review and instead pertain to the companion review on lacustrine varves where also general and fundamental principles of varve deposition classification and dating are covered zolitschka et al 2015 the postulated occurrence of varves in pre quaternary rocks is critically discussed in this review with representative examples in the case of non evaporitic laminations in fine grained ancient marine rocks such as banded iron formations and black shales laminations may not be varves but instead may have multiple alternative origins such as event beds or formation via bottom currents that transport and sort silt sized particles clay floccules and organic mineral aggregates in the form of migrating bedload ripples

tracing short cycles in long records the study of inter annual to inter centennial climate change from long sediment records examples from the santa barbara basin we present a review of digital imaging techniques to obtain highest resolution colour greyvalue time series from geological material from suitable sediments these methods can yield time series with subannual resolution they can be utilized for the detection of high frequency

effects of solar forcing and north atlantic oscillation on the climate of continental scandinavia during the holocene abstract 10 000 year long varved sediment records from lakes nautajarvi and korttajarvi finland provide evidence of climate and environment oscillations at multi decadal to millennial timescales we used two independent methods to extract periodic features from these time series of clastic laminae and assess their statistical reliability analyses revealed that seasonal sediment fluxes correspond to environmental changes with statistically significant periodicities of 1500 1800 1000 600 800 nearly 300 nearly 200 150 170 nearly 90 and 47 years showing variable coherency with different climate forcing factors and other palaeoproxy records in the northern hemisphere results indicate that the holocene winter climate in continental scandinavia was forced by a combination of several factors at least by solar variability and the north atlantic ocean atmosphere circulation patterns with varying influences through time

el nino in santa barbara basin diatom radiolarian and foraminiferan responses to the 1983 el nino event abstract santa barbara basin box cores collected in august of 1985 were sub sampled and processed in search of microfossil evidence of the 1983 el nino microplankton and microbenthos indicate the presence of that el nino bounded by non el nino conditions specifically the event is recognized by an increase in diatom diversity and the presence of several warm water taxa e g coscinodiscus plicatoides hemidiscus cuneiformis nitzschia kolaczekii pseudoeunotia doliolus thalassiosira lineata thalassiosira nodulolineata an increase in polycystine radiolarian flux and the presence of the eastern tropical pacific species spongaster pentas an increase in the diversity of planktonic foraminifera and the occurrence of the warm water species globoturborotalita rubescens there is also evidence for an oxygenation of the basin during the 1983 el nino as suggested by the increase in the abundance of the benthic foraminifera bolivina vaughani and by the decrease in the preservation of phaeodarian radiolarian spines which are best preserved under anoxic conditions a new onboard procedure for sampling of box cores and freezing of subcores is described

quaternary shelf sea palaeoceanography recent developments in europe abstract high quality palaeoceanographic reconstructions based on sequences preserved in shallow marine environments demonstrate that these constitute significant archives of climatic and oceanographic change such sequences are important first because their often very high resolution sometimes laminated nature enables high frequency cycles to be resolved and provides the basis for establishing spatial and temporal variability in the marine radiocarbon reservoir effect second sea level index points from shelves are important for the validation of glacio hydro isostatic geophysical models and for understanding sea level change during early deglaciation third shallow marine sequences contain excellent records of land ocean interaction often preserving paired terrestrial marine proxies in the same stratigraphic sequence a new development in shelf sea palaeoceanography is documenting the long term dynamics of shelf sea stratification this is the dominant hydrodynamic phenomenon of tide dominated shelf seas in the middle and high latitudes and has a profound influence on productivity and therefore global change through the carbon cycle detailing the evolution of seasonal stratification during eustatic highstands is therefore of relevance to the climate system

modern to late holocene deposition in an anoxic fjord on the west coast of canada implications for regional oceanography climate and paleoseismic history laminated sediments preserved in the anoxic inner basin of effingham inlet on the pacific coast of vancouver island british columbia canada yield a high resolution sediment deposition record spanning about 6000 yr the varying thickness of diatom terrigenous mud varves in sediment cores from the basin can be interpreted in terms of annual changes in surface productivity and freshwater input within the inlet similarly the occurrence of unlaminated mud units homogenites intercalated amongst the laminated sediments can be interpreted in terms of oceanic and climatic changes these units appear to be associated with coastal upwelling events that result infrequently in highly oxygenated oceanic water penetrating to the bottom of the inner and outer basins of the inlet the sedimentary record also contains massive and graded mud units considered to arise from debris flows and turbidity currents some of which were probably initiated by seismic events including a major event about 4500 14 c yr bp which may be earthquake related a total of seventeen oceanographic surveys of the inlet beginning in 1995 characterize the modern seasonal coastal upwelling regime and a unique bottom water oxygenation event which was

effects of structural deformation on formation of coalbed methane reservoirs in huaibei coalfield china tectonically deformed coal is defined as coal formed by superimposed reformations from tectonic stress the huaibei coalfield is typically composed of various tectonically deformed coals containing rich coalbed methane resources however the occurrence of coal seam in this area is complicated largely by the structural deformation which has not yet been evaluated systematically for exploration and exploitation of coalbed methane in this study tectonism in huaibei coalfield is discussed by combining systematic analyses on the occurrence of coal seams and the formation of coalbed methane reservoirs the study shows that with structural deformation in the study area the coal seams in huaibei coalfield are distributed in north south tectonic blocks and east west tectonic zones north tectonic block of huaibei coalfield is not favourable for exploitation of coalbed methane because of low gas content or disadvantageous structural conditions within the south tectonic block the east suzhou syncline contains high gas content but coal permeability is very low this area is generally not suitable for exploitation of coalbed methane and is a dangerous mining area due to gas outburst because of the widely developed mylonitic coals south suzhou and nanping synclines in the middle part of the south tectonic block are exposed to relatively weak structural deformations these synclines contain coals with high gas content and moderate permeability which are beneficial for exploration and exploitation of coalbed methane linhuan mining area in the south tectonic block is generally not suitable for exploitation of coalbed methane mainly because of well developed normal faults and interlayer slip structure and presence of mylonitic coal resulting in low gas content and poor structural conditions for mining coalbed methane in contrast guoyang mining area in the west part of the south tectonic block where tectonically deformed coal was generally underdeveloped is a potential area for exploration and exploitation of coalbed methane because of moderate gas content and possibly higher permeability of its coal

cyclostratigraphy and the early jurassic timescale data from the belemnite marls dorset southern england time series based on determinations wt of calcium carbonate and total organic carbon have been generated for the entire lower jurassic hemipelagic belemnite marls dorset southern britain this formation was deposited during early pliensbachian time at a paleolatitude of about 35 n in an epicontinental sea that was largely enclosed by the supercontinent of pangea the sequence contains compositionally diverse light and dark marl bedding couplets the thicknesses of which are notably reduced in the upper third of the section the regularity of the couplets in segments of the sequence combined with a regular amplitude modulation indicates an origin that is related to the orbital precession cycle i e one of the milankovitch parameters a timescale is developed by assigning a duration of 20 k y per couplet and this suggests that the entire formation represents at least 1 78 m y using the new timescale bundles of bedding couplets are shown to have periods consistent with the 123 k y component of the orbital eccentricity variations the amplitude of the couplets varies at the same frequencies as the bundle cycles in accordance with the interpretation that the couplets record precession and the bundles record eccentricity however despite having the same frequency of variation there is no consistent relationship coherence between the variations in amplitude of the couplet cycle and the bundle cycles as would be predicted by the eccentricity precession relationship this mismatch can be explained in terms of nonlinear behavior of a climatic system characterized by a varying response time or nonlinear response of the sedimentary system itself the data contain no evidence for orbital obliquity cycles because the obliquity cycle affects insolation principally at high latitudes the climatic factors that indirectly controlled the sedimentary cyclicity must have arisen at relatively low latitudes the belemnite marls timescale indicates highly variable minimum durations for ammonite zones and subzones true durations cannot be determined because it is possible that the succession is incomplete as a result of undetected erosion and or nondeposition a combination of the new results with cyclostratigraphic data from yorkshire northeast england and the southern alps switzerland indicates based on cycle counts that the pliensbachian stage lasted at least 4 82 m y marine sr isotope ratios appear to have decreased linearly from the start of jurassic time until the end of pliensbachian time the rate of decrease in 87 sr 86 sr established using the belemnite marls timescale was 0 000042 m y or less if the main part of the formation is incomplete using this rate with the observed changes in sr isotope ratios gives minimum durations of 2 86 m y for hettangian time 7 62 m y for sinemurian time and 6 67 m y for pliensbachian time

fundamentals of seismic rock physics during the past 50 years or so tremendous progress has been made in studying physical properties of rocks and minerals in relation to seismic exploration and earthquake seismology during this period many theories have been developed and many experiments have been carried out some of these theories and experimental results have played important roles in advancing earth sciences and exploration technologies this tutorial paper attempts to summarize some of these results

in situ identification of high vertical stress areas in an underground coal mine panel using seismic refraction tomography abstract because high stress anomalies can induce dynamic failures in the underground panels of coal mines the identification of high stress areas is critically important for mining safety we have identified areas of high vertical stress of an in situ longwall panel with seismic refraction tomography and interpreted our results using rock physics models constrained by core measurements since p and s velocities in rocks are stress sensitive mapping of them can provide useful information to identify areas of potential high stress we have inverted p and s velocities of main roof of an in situ panel with refraction tomography and converted them into vertical stress estimates using a calibration function from core measurements those estimates are classified into three groups high medium and low respectively identified zones of high vertical stress show qualitative agreement with monitored in panel microseismic data zones derived from p waves give a more plausible assessment than s waves we also discuss the link between high vertical stress areas and in panel faults because of the impact of the regional stress field and previously mined out voids the existing fault zone affects the redistribution of vertical stress in the underground panel

evaluation of coal texture distributions in the southern qinshui basin north china investigation by a multiple geophysical logging method abstract coal texture is indicative of coal mechanical strength which is important not only for evaluating coalbed methane cbm reservoir permeability but also for evaluating the possibility of coal and gas outbursts in underground coal mining this paper begins with a foundation of a geophysical logging based coal texture evaluation method that compares the digital logging data with the results from 108 coring samples then the method was applied to the analyses of coal textures in 39 cbm wells the results of which are discussed in terms of the vertical distribution of coal textures in the study area finally a ternary diagram based on thickness proportions of coal textures was used to identify reservoir compartments in the zhengzhuang field of the southern qinshui basin the results show that undeformed coals are easily distinguished from cataclastic and granulated coals because of the high den and gr of undeformed coals meanwhile cataclastic coal has lower response values of ac and lld than granulated coal which can be used in identifying cataclastic from granulated coal a multiple geophysical logging method combining the log data of den gr ac and lld was provided for predication of the coal textures in the zhengzhuang field the predicated results show that the coal seam can be vertically divided into three to eight sub layers with a typical interbedded pattern of undeformed and cataclastic coals on the upper and lower parts and granulated coal in the middle at a relatively large thickness the study area is divided into four major regions and 11 sub regions based on the classification of coal texture types the undeformed coal dominated region is located in the southwestern part of the study area indicating a low permeability in the coal reservoir the granulated coal dominated region is mainly in the northern and eastern parts of the study area and has resulted from deep burial and multi period structural activities the cataclastic coal dominated region is in the middle of the study area the coal reservoir in this region is possibly the most favorable for cbm production

a review of shear wave splitting in the crack critical crust summary over the last 15 years it has become established that crack induced stress aligned shear wave splitting with azimuthal anisotropy is an inherent characteristic of almost all rocks in the crust this means that most in situ rocks are pervaded by fluid saturated microcracks and consequently are highly compliant the evolution of such stress aligned fluid saturated grain boundary cracks and pore throats in response to changing conditions can be calculated in some cases with great accuracy using anisotropic poro elasticity ape ape is tightly constrained with no free parameters yet dynamic modelling with ape currently matches a wide range of phenomena concerning anisotropy stress shear waves and cracks in particular ape has allowed the anisotropic response of a reservoir to injection to be calculated predicted with hindsight and the time and magnitude of an earthquake to be correctly stress forecast the reason for this calculability and predictability is that the microcracks in the crust are so closely spaced that they form critical systems this crack critical crust leads to a new style of geophysics that has profound implications for almost all aspects of pre fracturing deformation of the crust and for solid earth geophysics and geology we review past present and speculate about the future of shear wave splitting in the crack critical crust shear wave splitting is seen to be a dynamic measure of the deformation of the rock mass there is some good news and some bad news for conventional geophysics many accepted phenomena are no longer valid at high spatial and temporal resolution a major effect is that the detailed crack geometry changes with time and varies from place to place in response to very small previously negligible changes however at least in some circumstances the behaviour of the rock in the highly complex inhomogeneous earth may be calculated and the response predicted opening the way to possible control by feedback the need is to devise ways to exploit these new opportunities in the crack critical crust recent observations from the smsites project at husavik in northern iceland gathered while this review was being written display the extraordinarily sensitivity of in situ rock to small changes at great distances the effects are far too large to occur in a conventional elastic brittle crust and their presence confirms the highly compliant nature of the crack critical crust

natural and antropogenic enrichments of trace metals in peat profiles abstract samples of mosses peats lake sediments and clays were collected from 35 canadian peatlands and analyzed for cr cu fe mn ni pb u v and zn the average composition of the analyzed peats is significantly depleted in fe and mn and enriched in cu u zn and pb compared to typical crustal abundance in contrast ni v and cr are neither significantly enriched nor depleted relative to typical crustal abundance the compositions of the peats vary widely depending on their botanical composition and degree of decomposition the amount of mineral matter present and depth in the peatland to summarize the voluminous trace metal chemistry data a composite sphagnum bog profile was constructed for each metal from the individual profiles using the peat stratigraphy typical of sphagnum bogs in eastern canada to do this the trace metal concentrations of samples of the same botanical composition and similar degree of decomposition were averaged after taking into account the differences in mineral matter contents of the sediments enrichments and depletions through the composite bog profile have been calculated for each stratigraphic layer relative to the average composition of the underlying mineral sediments clays these calculations emphasize the dynamic behaviour of cu u zn and pb and the conservative behaviour of ni v and cr through the composite peat profile cu zn and pb are enriched in ombrotrophic surface peat layers because of significant anthropogenic atmospheric inputs cu and u are enriched in minerotrophic basal peat layers because of natural geochemical processes ni v and cr are neither significantly enriched nor depleted we present a summary of the pore water chemistry ph so42 ch4 of a representative sphagnum bog which shows that these sediments typically range from being acidic ph approximately 4 and oxidizing at the surface above the water table to neutral ph approximately 7 and strongly reducing in the subsurface layers predominance area diagrams log po2 ph based upon equilibrium chemical thermodynamics were constructed and are presented for cr cu fe mn pb u and zn using the predominance area diagrams the behaviour of the dynamic metals in peatland environments is explained in terms of the influence of ph and redox potential on the relative stabilities of solid and aqueous species