Multiproxy diet analysis of the last meal of an early Holocene Yakutian bison          下载免费PDF全文

BAS VAN GEEL  ALBERT PROTOPOPOV  IAN BULL  ELZA DUIJM  FIONA GILL  YOURI LAMMERS  ALINE NIEMAN  NATALIA RUDAYA  SVETLANA TROFIMOVA  ALEXEI N. TIKHONOV  RUTGER VOS  SNEZHANA ZHILICH  BARBARA GRAVENDEEL 《第四纪科学杂志》2014,29(3):261-268

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The ringed seal (Phoca hispida) spring diet in northwestern Spitsbergen, Svalbard     

IAN GJERTZ  CHRISTIAN LYDERSEN 《Polar research》1986,4(1):53-56

A total of 284 ringed seals (Phoca hispida) were sampled to determine their diet in the spring of 1981 and 1982. Few seals contained identifiable stomach contents. No significant age-or sex-related differences in choice of prey were found. It seems that in spring northwestern Spitsbergen ringed seals prey upon arctic cod (Boreogadus saida) , decapods and larger amphipods.? Diet, ringed seal, Svalbard .  相似文献   

Studies of the ringed seal (Phoca hispida Schreber 1775) in its breeding habitat in Kongsfjorden, Svalbard   总被引：1，自引：0，他引：1  

CHRISTIAN LYDERSEN  IAN GJERTZ 《Polar research》1986,4(1):57-63

This study was conducted in Kongsfjorden, Svalbard, from mid-March through April 1984. Local Greenland sled dogs were used to locate subnivean ringed seal lairs. A total of 90 lairs were found and excavated. These constituted 28 lairs classified as birth lairs, 22 as tiggak (rutting male) lairs, and 40 which could not be classified. The first birth lair was found on 24 March. There was significantly more snow covering birth lairs than tiggak lairs, and birth lairs were also shown to be significantly larger than tiggak lairs. The positions of the lairs were plotted on a map, and distances between neighbouring seal lairs were used as an indicator of territorial size. Arctic foxes had attacked 19 lairs and 6 of these had resulted in a kill (32%). Polar bears had attacked 13 lairs with one kill (8%).  相似文献   

THE SPINY-LOBSTER FISHERY IN CUBA*     

IAN T. JOYCE 《Geographical review》1997,87(4):484-503

ABSTRACT. The spiny-lobster fishery, the most valuable fishery in Cuba, is unique among those in major lobster-producing countries because of its combination of strong central control and absence of standardization and mechanization in fishing gear. Cooperation rather than competition among fishing vessels is promoted by exclusive fishing zones and fleet organization. These measures, along with the use of storage centers, simple vessels, and inexpensively constructed fishing gear, have promoted spatial rationality and cost reduction in the fishery and made it one of the most successful spiny-lobster fisheries in the world.  相似文献   

Basalt and Sediment Geochemistry and Magma Petrogenesis in a Transect from Oceanic Island Arc to Rifted Continental Margin Arc: the Kermadec--Hikurangi Margin, SW Pacific   总被引：2，自引：1，他引：1  

GAMBLE  JOHN; WOODHEAD  JON; WRIGHT  IAN; SMITH  IAN 《Journal of Petrology》1996,37(6):1523-1546

Sediment mixing and recycling through a subduction zone canbe detected in lead isotopes and trace elements from basaltsand sediments from the Kermadec-Hikurangi Margin volcanic arcsystem and their coupled back-arc basins. Sr, Nd and Pb isotopesfrom the basalts delineate relatively simple, almost overlapping,arrays between back-arc basin basalts of the Havre Trough-NgatoroBasin (⁸⁷Sr/⁸⁶Sr = 0.70255; _Nd=+9.3; ²⁰⁶Pb/²⁰⁴Pb = 18.52; ²⁰⁸Pb/²⁰⁴Pb= 38.18), island arc basalts from the Kermadec Arc togetherwith basalts from Taupo Volcanic Zone (⁸⁷Sr/⁸⁶Sr 0.7042; _Nd= +5; ²⁰⁶Pb/²⁰⁴Pb= 18.81; ²⁰⁸Pb/²⁰⁴Pb = 38.61), and sedimentsderived from New Zealand's Mesozoic (Torlesse) basement (⁸⁷Sr/⁸⁶Sr 0.715; _Nd —4; ²⁰⁶Pb/²⁰⁴Pb 18.86; ²⁰⁸Pb/²⁰⁴Pb 38.8).Basalts from the arc front volcanoes have high Cs, Rb, Ba, Th,U and K, and generally high but variable Ba/La, Ba/Nb ratios,characteristic of subduction-related magmas, relative to typicaloceanic basalts. These signatures are diluted in the back-arcbasins, which are more like mid-ocean ridge basalts. Strongchemical correlations in plots of SiO₂ vs CaO and loss on ignitionfor the sediments (finegrained muds) are consistent with mixingbetween detrital and biogenic (carbonate-rich) components. Otherdata, such as Zr vs CaO, are consistent with the detrital componentcomprising a mixture of arc- and continent-derived fractions.In chondrite-normalized diagrams, most of the sediments havelight rare earth element enriched patterns, and all have negativeEu anomalies. The multielement diagrams have negative spikesat Nb, P and Ti and distinctive enrichments in the large ionlithophile elements and Pb relative to mantle. Isotopic measurementsof Pb, Sr and Nd reveal restricted fields of Pb isotopes butwide variation in Nd and Sr relative to other sediments fromthe Pacific Basin. Rare K-rich basalts from Clark Volcano towardthe southern end of the oceanic Kermadec Island Arc show unusualand primitive characteristics ( 2% K₂O at 50% SiO₂, Ba 600p.p.m., 9–10% MgO and Ni > 100 p.p.m.) but have highlyradiogenic Sr, Nd and Pb isotopes, similar to those of basaltsfrom the continental Taupo Volcanic Zone. These oceanic islandarc basalts cannot have inherited their isotope signatures throughcrustal contamination or assimilation—fractional crystallizationtype processes, and this leads us to conclude that source processesvia bulk sediment mixing, fluid and/or melt transfer or somecombination of these are responsible. Although our results showclear chemical gradients from oceanic island arc to continentalmargin arc settings (Kermadec Arc to Taupo Volcanic Zone), overlapbetween the data from the oceanic and continental sectors suggeststhat the lithospheric (crustal contamination) effect may beminimal relative to that of sediment subduction. Indeed, itis possible to account for the chemical changes by a decreasenorthward in the sediment flux into the zone of magma genesis.This model receives support from recent sediment dispersal studiesin the Southern Ocean which indicate that a strong bottom current(Deep Western Boundary Current) flows northward along the easterncontinental margin of New Zealand and sweeps continental derivedsediment into the sediment-starved oceanic trench system. Thetrace element and isotopic signatures of the continental derivedcomponent of this sediment are readily distinguished, but alsodiluted in a south to north direction along the plate boundary. KEY WORDS: subduction zone basalts; sediments; Sr-, Nd-, Pb-isotopes; trace elements ^*Present address: School of Earth Sciences, University of Melbourne, Parkville, Vic. 3052, Australia.  相似文献   

Basalts from Leg 6 of the Deep-Sea Drilling Project     

RIDLEY  W. IAN; RHODES  J. M.; REID  ARCH M.; JAKES  P.; SHIH  C.; BASS  M. N. 《Journal of Petrology》1974,15(1):140-159

Basalt was successfully cored at Site 54 in the Parace VelaBasin of the Philippine Sea, and at Site 57 on the CarolineRidge as part of Leg 6 of the Deep Sea Drilling Project. Site54 basalts are altered, but selected major and trace elements,particularly REE allow their characterization as high-aluminaolivine tholeiites, with flat REE patterns, no Eu anomalies,and low dispersed trace-element contents. Basalt from Site 57is distinctly different, with higher TiO₂, P₂O₅, Fe/Mg ratio,and dispersed trace elements, low Ni, Mg, and a strongly fractionatedREE pattern. Derivation by fractionation of transitional basaltis suggested. Varying degrees of alteration of Site 54 basalts has causeddepletion in MgO and addition of Rb, Sr, Ba, Ka₂O, and Na₂O.Mineralogically these changes have resulted in alteration ofolivine and pyroxene, but plagioclase and iron-titanium oxidesremain unaffected. Microprobe data are presented for olivine, clinopyroxene, plagioclase,Fe-Ti oxides, and chrome-spinel in all three basalts. In 54–4,54–8 pyroxenes are zoned from salite to ferroaugite, andshow erratic decrease in A1₂O₃ and TiO₂ with increasing ironcontent. In 57–2, pyroxenes are more magnesian than thosein site 54 basalts, and show an increase in A1₂O₃ and TiO₂ withiron-enrichment. The anomalous behaviour of Al₂O₃ and TiO₂ insome clinopyroxenes, and the close textural relationship ofpyroxene and magnesian olivine in 57–2 basalt, suggestthese minerals are xenocrystic, and were incorporated duringmagma ascent. Spinels of picotite composition in early-formed,and possibly xenocrystic, olivine, and plagioclase crystallizedprior to magma eruption, and may have begun crystallizationwithin the mantle. Site 54 basalts add further confirmation that inter-are basaltsclosely resemble ocean ridge tholeiites, although there is apaucity of data from inter-are environments. Site 57 basaltis chemically and mineralogically distinct from ocean ridgebasalts and may be related to similar volcanics erupted on theCaroline Islands.  相似文献   

Wollastonite--Scapolite Assemblages as Indicators of Granulite Pressure-Temperature-Fluid Histories: The Rauer Group, East Antarctica   总被引：4，自引：0，他引：4  

HARLEY  SIMON L.; BUICK  IAN S. 《Journal of Petrology》1992,33(3):693-728

Mid-Proterozoic ( 1000 Ma) granulite facies calc-silicates fromthe Rauer Group, East Antarctica, contain grossular-wollastonite-scapolite-dinopyroxene( + quartz or calcite) assemblages which preserve symplectiteand corona textures typically involving the growth of secondarywollastonite. The textures include (1) wollastonite rims betweenquartz and calcite; (2) wollastonite-plagioclase rims and intergrowthsbetween quartz and scapolite; (3) wollastonite-scapolite-clinopyroxeneinter-growths replacing grossular; and (4) wollastonite-plagioclasesymplectites replacing grossular or earlier symplectites (3). Reactions between grossular, scapolite, wollastonite, calcite,quartz, anorthite, and vapour, have been modelled in the CaO-Al₂O₃SiO₂-H₂O-CO₂and more complex systems using the internally consistent data-setof Holland & Powell (1990). Reactions producing scapoliteand wollastonite consume vapour as temperature increases (i.e., carbonation), in agreement with the results of Moecher &Essene (1990). These calc-silicates can therefore behave asfluid sinks under high-grade conditions. Conversely, they maybe important fluid sources on cooling and contribute to theformation of post-metamorphic CO₂rich fluid inclusions in isobaricallycooled granulites. P-T-_CO2 diagrams calculated for typical phase compositions (e.g., garnet, scapolite) demonstrate that the observed texturesare a record of near-isothermal decompression at 800–850 C, consistent with P—rpath determinations based on otherrock types from the Rauer Group. For example, texture (2) resultsfrom crossing the reaction Scapolite + Quartz = Wollastonite + Plagioclase + V on decompression, at 6. 5–7 kb, 820 C, and a_CO2 of0–4–0–5. Furthermore, correlations betweenmodes of product phases (e. g., wollastonitexlinopyroxene) andreactant garnet composition preclude open-system behaviour inthe formation of these textures, consistent with post-peak vapour-absentreactions such as Grossular + Calcite + Quartz = Wollastonite + Scapolite occurring on decomposition at high temperatures (>800C). Reaction textures developed in calc-silicates from other granuliteterranes often involve the formation of grossular ( + quartz calcite) as rims on wollastonite-scapolite, or replacementof wollastonite by calcite-quartz. These textures have developedprincipally in response to cooling below 780–810 C andmay be signatures of near-isobaric cooling. Infiltration ofhydrous fluid is not a necessary condition for the productionof garnet coronas in wollastonite-scapolite granulites. ^*Present address: Department of Earth Sciences, University ofMelbourne, Parkville, Victoria 3052, Australia  相似文献   

Biotite Equilibria and Fluid Circulation in the Klokken Intrusion   总被引：3，自引：2，他引：1  

PARSONS  IAN; MASON  R. A.; BECKER  S. M.; FINCH  A. A. 《Journal of Petrology》1991,32(6):1299-1333

Chemical variation in biotite from the KJokken gabbro-syeniteintrusion in the Proterozoic Gardar province in South Greenlandhas been investigated by electron probe and, for F and Li, ionmicroprobe. Most mica occurs in small amounts as fringes onilmenomagnetite or fayalite, rarely as an intercumulus or poikiliticphase. The micas range continuously from Phlog₇₀Ann₃₀ in a gabbro,to Phlog₄Ann₉₆ in the most evolved (slightly persilicic andperalkaline) syenite. In the syenites Fe-Mg partitioning betweenbiotite and olivine can be described by a single distributioncoefficient, K_d = XF X^Biot_Ms/X^Biot_Fe 3, suggesting that thesereactant phases mix ideally at the reaction T. Experimentaldata for Fe-Mg exchange via aqueous chloride solutions (Schulien,1980) imply low T (32Q?C). F was absent in the experiments andmay significantly affect the exchange equilibrium. K_d in thegabbros is 1, consistent with equilibrium via a fluid depletedin F because of crystallization of large amounts of amphibole. Al, Mn, and Ti vary regularly throughout the series and canbe used as markers of cryptic variation in the layered syenites.(Al + Si): 22 O is always in the range 7.7–7.85. A1/(A1+ Si) decreases from 0.31 in gabbros to 0.25 in the most Fe-richmicas. Li is always < 260 ppm w. In the syenite series, Fshows a near-linear inverse relationship with Fe/(Fe + Mg) whichpasses close to OF at Ann₁₀₀ with l.4 wt% F(0–7 F to 44positive charges) at Ann₄₄. Biotites in the gabbro unit (whichforms an outer sheath to the intrusion) have relatively lessF, probably because it was consumed by coexisting amphibole.^I8O is similar for both gabbros and syenites, and it is unlikelythat an envelope fluid was involved in the reactions. G reachesa maximum of 0.3 wt. % in biotite except for that in one syenitesample with 0–7 wt. %. Calculation of relative F-OH fugacitiesfrom the reaction OH-phlogopite + F-annite = F-phlogopite +OH-annite, as calibrated by Munoz (1984), appears to suggestthat each horizon in the layered series was in equilibrium witha slightly different fluid. In view of the intimate interleavingof these lithologies, this is improbable. The equilibrium constantof the exchange reaction, obtained from the experimental data,seems not to be appropriate to the Klokken assemblage, or toother examples of regular F-Fe avoidance. Explanations may includeshort-range Fe-Mg ordering in the natural examples or the effectof additional components in the fluid. F contents are high incomparison with biotites from calc-alkaline complexes; highmagmatic F may account for the igneous layering common in theGardar. Temperatures calculated from reactions involving fayaliteand magnetite show that most biotites grew subsolidus. The F-poorannites grew > 300 ?C subsolidus even when texturally intercumulus.Stable isotope data are consistent with the separation and retentionof a deuteric fluid during the final stage of magmatic crystallization.Klokken was not generally subject to the pervasive, long-range(in both distance and time) dydrothermal interactions demonstratedin calcalkaline and theleiitic intrusions, although more extensivefluid flow is indicated for the more permeable laminated syenites.The biotites preserve chemical variation indicating local equilibriumwith other mafic phases, and halogens provide a useful markerof subsolidus fluid flow.  相似文献   

New Lateglacial fauna and early Mesolithic human remains from northern England     

IAN R. SMITH  DAVID M. WILKINSON  HANNAH J. O'REGAN 《第四纪科学杂志》2013,28(6):542-544

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Practical aspects of calibrating and selecting unit hydrograph-based models for continuous river flow simulation     

IAN LITTLEWOOD 《水文科学杂志》2013,58(5):795-811

Abstract

A continuous simulation rainfall-streamflow modelling approach that identifies unit hydrographs for total streamflow has been applied to an 11-year record from a national hydrometric monitoring network catchment in the UK. The model is of the parametrically parsimonious conceptual model (PPCM) type that can make efficient use of rainfall, streamflow and air temperature data readily available from established national and regional monitoring networks. A multiple split-sample model calibration and simulation analysis is presented that reveals some guiding principles for calibrating and applying PPCMs generally. The inadequacy of a one-dimensional objective function for calibrating best PPCMs is demonstrated. A two-dimensional objective function approach is superior but is shown to be unreliable in some cases, confirming the need for additional critical inspection of other model performance statistics, model parameters and time series plots as an integral part of the model calibration process. A strong tendency evident from the multiple split-sample analysis is that, for the catchment studied, models that fit relatively well in calibration mode perform relatively poorly in simulation mode.  相似文献