当前位置：文档之家 › Variations in benthic fauna underneath an effluent mixing zone

Variations in benthic fauna underneath an effluent mixing zone

  • 格式：pdf
  • 大小：312.69 KB
  • 文档页数：7

Variations in benthic fauna underneath an effluent mixing zoneat a marine oil terminal in Port Valdez,AlaskaArny L.Blanchard *,Howard M.Feder,David G.ShawInstitute of Marine Science,School of Fisheries,Ocean Sciences,University of Alaska,P.O.Box 757220,Fairbanks,Alaska 99775-7220,USAAbstractThe distributions of hydrocarbons and infauna in sediments below a permitted mixing zone for the disposal of treated ballast waters in Port Valdez,Alaska were examined annually,1999–2001.The associations of biological measures and the abundance of selected benthic organisms to total aromatic hydrocarbons (TARO)ranged up to large-sized effects,as compared against minimum-effect criteria (j r j P 0:63).The apparent sensitivity of three polychaete worms to low levels of hydrocarbons makes them particularly useful as indicators of future changes in spatial distributions of hydrocarbons associated with discharged effluent.In 2001,sediment TARO concentrations decreased and the correlation values of TARO to biotic variables were generally less than in 1999and 2000.Evidence supports a conclusion of a strong but spatially limited association of some fauna with accumulations of petroleum hy-drocarbons in these sediments.Ó2003Elsevier Ltd.All rights reserved.Keywords:Port Valdez,Alaska;Hydrocarbons;Disturbance;Infauna;Galathowenia ;Melinna ;Axinopsida1.IntroductionPort Valdez,a fjord within Prince William Sound,Alaska,is the terminus of the Trans-Alaska oil pipeline (Fig.1).Interest in protecting this fjord from environ-mental damage by human activities is high and concerns include the disposal of treated ballast waters from in-coming tankers at a marine oil terminal (Blanchard et al.,2002).Oily ballast water is offloaded from arriving tankers and transferred to an onshore treatment plant before crude oil can be loaded.Ballast water is treated to remove crude oil and then discharged through an outfall line fitted with diffuser ports (the diffuser)some 50m from shore in depths of 65–75m (see Shaw and Hameedi,1988;Blanchard et al.,2002for details on quantities,sources,and fate of hydrocarbons in Port Valdez).Alteration of infaunal communities in marine envi-ronments receiving petroleum residues has been ob-served.Pearson and Rosenberg (1978)demonstrate that tolerant species can occur close to a source of pollutants,grading to intolerant organisms a distance away.Fieldstudies of the effects of oil and gas exploration on ben-thic infauna (considering both drilling mud and associ-ated hydrocarbon burdens)show such trends (e.g.,Gray et al.,1990;Olsgard and Gray,1995;Montagna and Harper,1996).Similar patterns also occur at natural marine oil seeps where infauna assemblages exhibit lower diversity and dominance by opportunistic organ-isms (Spies and Davis,1979;Steichen et al.,1996).En-richment of faunal communities (increased densities of some taxa within the ambient benthic assemblage due to locally increased food resources from allochthonous sources)also can occur over short distances due to in-creased numbers of bacteria associated with the degra-dation of oil (Spies and Davis,1979).Likewise,investigations near marine oil terminal facilities show increased abundances of opportunistic polychaetes (capitellid,cirratulid,and spionid polychaetes)in asso-ciation with increased sediment hydrocarbons (Seng et al.,1987;Westwood et al.,1987;May and Pearson,1995;Blanchard et al.,2002).Following a short-term,localized contamination of sediments by weathered hy-drocarbons and an increase in opportunistic taxa at a site close to the diffuser in Port Valdez (Blanchard et al.,2002),we initiated a study in 1998to assess spatial and temporal aspects of sediment hydrocarbon distributions below the permitted mixing zone (Shaw et al.,1999).*Corresponding author.E-mail addresses:arnyb@ (A.L.Blanchard),feder@ (H.M.Feder),ffdgs@ (D.G.Shaw).0025-326X/$-see front matter Ó2003Elsevier Ltd.All rights reserved.doi:10.1016/S0025-326X(03)00324-2/locate/marpolbulMarine Pollution Bulletin 46(2003)1583–1589Selected sites were re-sampled annually,1999through 2001,and biological sampling was included.The con-clusions from the study are discussed here.2.MethodsThe sampling transect lies on the main axis of a hy-drocarbon gradient adjacent to the diffuser(Shaw et al., 1999).These sampling locations,Stations141–147(es-tablished in1998),211(established in1999),203and204 (established in2000,positioned to follow the depth contour and to avoid physical obstructions),and212 (established in2000)(Fig.1),are62–85m deep.Data from single biological samples archived from the1998 investigation(Stations142,143,and146)are presented in tables andfigures but not used in correlation analyses. Samples were collected in the last week of August orfirst week of September using a van Veen grab(0.1m2). Hydrocarbon and biological samples were collected from each grab and analyzed according to methods outlined in Blanchard et al.(2002).Hydrocarbon results are summarized as the sum of18individually quantified aromatics(total aromatics(TARO)).Biological mea-sures include infaunal abundance,biomass,and number of taxa as well as the abundance of11numerically dominant taxon groups.Correlation values were determined between TARO and selected biotic variables including total abundance, biomass,number of taxa,and the abundance of selected taxon groups for each year.The natural logarithmic transformation was applied to TARO values.Numeri-cally dominant taxa were selected for correlation ana-lysis.Correlation values were determined using data for individual samples rather than station means.In an application of the minimum-effects hypothesis(Murphy and Myors,1998),Blanchard et al.(2002)suggested standardized effect sizes(Cohen,1988)for invertebrate studies of small,f¼0:2;medium,f¼0:5;and large, f¼0:8.These effect-size criteria are converted to crite-ria appropriate for correlation testing(Cohen,1988), with coefficients of j r j P0:2considered small effects, coefficients of j r j P0:45considered medium effects,and coefficients of j r j P0:63considered as large effects. Correlation coefficients less than0.2are considered negligible.Relative to1999and2000,2001substrates were very compact and exceptionally difficult to sample. Grabs were often less than full,so rank correlation methods were used for2001.3.ResultsAverage TARO,and abundance and biomass of in-fauna are presented in Table1.TARO concentration and infaunal density were highest at Station143in1998 reaching values of755.1ng gÀ1and2760ind.mÀ2,re-spectively.Biomass was highest,8.3g mÀ2,at Station 146in2000,and the‘‘number of taxa’’greatest at Sta-tion142in2000,with31taxa observed.The lowest TARO concentration,11.8ng gÀ1,was observed at Station211in1999,while the lowest faunal density, biomass,and number of taxa,150ind.mÀ2,0.9g mÀ2, and11taxa,were observed at Station141in2000.The high average abundance at Station143in1998reflects high densities of the polychaetes Capitellidae(520in-d.mÀ2;dominated by worms in the genus Capitella), Cirratulidae(720ind.mÀ2),and Polydora socialis(290 ind.mÀ2)and the thyasirid bivalve Axinopsida serricata (920ind.mÀ2)(Table2and Fig.2).Capitellid and cirratulid worms were less abundant in other years.Correlation analyses indicate some medium and large associations between TARO and biotic variables.The relationship of TARO to total abundance and biomass for1999shows medium-sized effects(j r j P0:45;Table 3).For2000,the association of TARO to abundance is medium-sized while the association of the number of taxa to TARO is large(j r j P0:63).For2001,the rank associations of abundance and biomass to TARO are small(j r j P0:20)but large for the number of taxa.The abundance values of A.cyclia,A.serricata,and P.so-cialis for1999and2000,are positively correlated to TARO with generally medium to large-sized effects (Table3).All these taxa demonstrated peaks in abun-dance near the diffuser(Fig.2).Mostly large,negative (inverse)associations are observed between the abun-dance values of Melinna cristata,Galathowenia oculata, and Nephtys punctata and TARO in1999and2000.The numbers of these organisms,and particularly those of M.cristata,are reduced close to the diffuser.However, neither G.oculata or M.cristata are particularly abun-dant at any of the sampling locations.The abundance values of polychaete taxa Cirratulidae,Capitellidae, Exogone spp.,and P.steenstrupi are not clearlyrelatedto TARO as correlation values were small or negligible (Table3).In2001,rank correlation values are of a smaller size as only two values between taxon groups and TARO,for G.oculata and Lumbrineris sp.,are medium-sized.All others are small or negligible.4.DiscussionLong-term,broad-scale studies in Port Valdez(Feder et al.,1973;Feder and Matheke,1980;Feder and Jewett, 1988;Blanchard et al.,2002)were designed to provide a record for subtidal infaunal communities against which disturbance due to increased sediment hydrocarbons could be identified.Pearson and Rosenberg(1978)sug-gest that disturbance due to organic enrichment will be apparent as a rise in the numbers of opportunists fol-lowed by decreases in sensitive taxa with increasing pollution.Blanchard et al.(2002)indicate that this is the pattern likely to be observed in Port Valdez because of the lack of sensitive taxa(e.g.,echinoderms and am-phipods)in the study area and treatment of the ballast waters.In1995–1997a rise in opportunists followed by a decrease in all taxons was observed at one station in Port Valdez in association with sediment contamination near the diffuser(Blanchard et al.,2002).The spacing of sampling locations in that study,however,was broader than the range of effects and did not allow for the identification of chronic effects.Following this distur-bance event in1995–1997,the present study was initi-ated on a smaller-scale to document temporal changes in the distribution and concentrations of hydrocarbons derived from diffuser effluent in sediments as well as any associated biological effects.Correlations noted in this study indicate a strong association between the benthic community in Port Valdez and hydrocarbons from diffuser effluents.Rela-tionships between TARO and biotic measures are mostly of lesser magnitude but occasionally large(as determined by comparison against minimum-effect cri-teria).Medium to large correlations are recorded for the abundances of numerically dominant taxa,suggesting a moderate but mixed influence(i.e.,both positive and negative associations)of hydrocarbon concentrations on biota.In2001,the TARO concentrations were lower and strength of correlations decreased.These associations doTable1Average total aromatics(TARO),percent total organic carbon(TOC)abundance,and biomass for the grid stations sampled in1998and1999 (values for stations with multiple replicates are averages)Year Station#Replicates TARO(ng gÀ1)TOC(%)Abundance(ind.mÀ2)Biomass(g mÀ2)Number of taxa 1998142199.30.61250 1.0611 1431755.1–2760 3.60171461105.70.691380 3.2321 1999141177.00.70320 1.5014 142390.60.73357 4.7024143392.90.83610 3.78251453123.20.921080 3.4326146192.90.781460 3.9019147124.70.57560 3.0613211111.80.62510 2.1114 2000141167.50.681500.9311 142386.00.74777 2.63311433497.0 2.231023 4.15201453112.70.91553 1.4025146145.20.686808.3021147123.20.74760 4.6219203118.80.6055026.8419204127.30.59340 2.4720211115.50.60710 4.2220212113.50.65450 3.2414 2001141139.30.63690 3.6221 142338.00.66760 3.2731143383.6 1.34590 3.3918145356.60.90710 3.1124146130.60.565307.9716147155.70.8089021.9217203136.90.5812707.3421204147.00.667107.1817211145.50.67970 6.7519212143.20.6010208.4418A.L.Blanchard et al./Marine Pollution Bulletin46(2003)1583–15891585not directly imply a cause and effect relationship,as other unmeasured environmental covariates may be the factors controlling faunal distributions.The observed associations,however,dofit expectations for fauna under the Pearson and Rosenburg model of disturbance (Pearson and Rosenberg,1978).Associations of hydrocarbons and faunal abundance are particularly apparent for six taxa.Three polychae-tes,G.oculata,Melinna cristata,and N.punctata show a lower abundance near the diffuser.G.oculata and M. cristata always occur in low numbers near the diffuser. Numbers of N.punctata were depressed near the diffuser in1999–2000when TARO concentrations were high, and increased substantially with lower TARO concen-trations in2001.G.oculata,is identified as intolerant of petrogenic hydrocarbons(Olsgard and Gray,1995) while another member of the genus Melinna,M.pal-mata,is an indicator species for pollution in European coastal waters(Grehan,1991;Langston et al.,1999). There is no information available for N.punctata al-though some information is published for other members of this family(e.g.,Fauchald and Jumars,1979).The apparent sensitivity of these species to low levels of hy-drocarbons render them particularly useful as indicators of future changes in the spatial distribution of hydro-carbons in Port Valdez.G.oculata(as Myriochele ocu-lata)also shows lower abundance at two stations within the mixing zone,as compared to nearby referenceTable2Abundance values(ind.mÀ2)of numerically dominant taxa in1998–2001Taxon Station14114214319992000200119981999200020011998199920002001 Adontorhina cyclia010503032310609320750 Axinopsida serricata3002040153143479208333027 Capitellidae3002020367105203137 Cirratulidae900300132310720573020 Exogone sp.00003201030330 Galathowenia oculata0201300710270700 Lumbrineris sp.010200102017101037 Melinna cristata1030010713301007 Nephtys punctata30208050405311710507133 Polydora socialis00200350223290170153177 Prionospio steenstrupi1003007871330003 1451461471999200020011998199920002001199920002001 Adontorhina cyclia1039033100802030011010 Axinopsida serricata3834013480310904028019080 Capitellidae67107502020002070 Cirratulidae15733307016030201040150 Exogone sp.33302310130001000 Galathowenia oculata70710107040201030 Lumbrineris sp.137105020101010100 Melinna cristata030000010100 Nephtys punctata573787605080210100100280 Polydora socialis4013322770600100060 Prionospio steenstrupi10333175036030200400203204211212200020012000200119992000200120002001 Adontorhina cyclia2060006030805060Axinopsida serricata20020030120140601605080Capitellidae1001020001000Cirratulidae101002020100180030Exogone sp.10010030030500Galathowenia oculata10250108030804030100Lumbrineris sp.20203020010201030Melinna cristata305020404040801020Nephtys punctata902006010010014013060220Polydora socialis070090010200110Prionospio steenstrupi2050001030700201586 A.L.Blanchard et al./Marine Pollution Bulletin46(2003)1583–1589stations (Blanchard et al.,2002).The thyasirid bivalves Adontorhina cyclia and Axinopsida serricata and the polychaete Polydora socialis (a family and genera known as opportunistic;e.g.,Pearson and Rosenberg,1978)increase in numbers near the diffuser,possibly enhanced by bacteria and particulate organic carbon,as foodinTable 3Correlation values of biological measures and taxon abundance values to total aromatic (TARO)concentrations Variable199920002001r P -value Effect size r P -value Effect size r a P -value Effect size Abundance 0.500.082Medium 0.560.024Medium )0.240.374Small Biomass 0.480.096Medium )0.390.131Medium )0.240.368Small #Taxa)0.120.728Negligible )0.650.007Large )0.640.007Large Adontorhina cyclia 0.490.091Medium 0.84<0.001Large )0.120.667Negligible Axinopsida serricata 0.420.150Small 0.690.003Large )0.270.307Small Capitellidae 0.420.151Small )0.260.925Small 0.050.851Negligible Cirratulidae 0.390.193Small 0.060.838Negligible 0.170.522Negligible Exogone spp.0.170.576Negligible )0.060.820Negligible )0.130.644Negligible Galathowenia oculata )0.840.000Large )0.450.077Medium )0.590.017Medium Lumbrineris sp.)0.210.503Small )0.620.010Medium )0.440.091Medium Melinna cristata )0.780.002Large )0.510.045Medium )0.100.708Negligible Nephtys punctata )0.720.005Large )0.680.004Large )0.260.334Small Polydora socialis0.460.117Medium 0.670.005Large 0.200.464Small Prionospio steenstrupi0.340.261Small)0.150.580Small)0.380.147SmallaRank correlations.A.L.Blanchard et al./Marine Pollution Bulletin 46(2003)1583–15891587diffuser effluent(Blanchard et al.,2002).Beyond basic biological descriptions(e.g.,Scott,1986;Slack-Smith, 1994),little is known about these thyasirid bivalves but Blanchard et al.(2002)suggest that A.serricata (as Axinopsida spp.)may be functioning as an op-portunistic species in Port Valdez(see also Rygg, 1985).Some members of the family Thyasiridae are known to be hosts for chemosymbiotic bacteria that degrade sediment sulphides(Dando and Spiro,1993). Slack-Smith(1994),however,indicates that A.serricata is not a host for these bacteria and Burd(2002)found A. serricata in significantly lower densities in sulphide-rich sediments.The conclusions of our study agree with other re-search projects from Port Valdez.Intertidal studies have rarely identified variations of fauna attributable to ma-rine terminal activities(Feder and Bryson-Schwafel, 1988;Blanchard and Feder,1997,2000a,b).An ex-ception is a small decrease in barnacle abundance fol-lowing a small oil spill in the terminal area in1980 (Rucker,1983).Shaw(1988)discusses accumulations of hydrocarbons in bivalves and sediments in Port Valdez and concludes that decreasing concentrations over time are likely due to better treatment methods of oily ballast water and declining volumes of oil shipments.Recently, Payne et al.(2001)concluded that although a hydro-carbon signature of Alaska North Slope crude oil was found in mussel tissues from within and remote from the marine oil terminal,intertidal and subtidal biota likely experience low stress as a result of treated ballast-water disposal in Port Valdez,as supported by mussel and limpet studies by Blanchard and Feder(1997,2000a,b). Blanchard et al.(2002)concluded that there was a small effect on subtidal infauna due to a short-term and lo-calized increase in sediment hydrocarbons.The use of fixed rather than randomly selected sampling locations in most of the above studies may bias their conclusions. In all studies,however,observed effects were limited to small areas and measured hydrocarbon concentrations provide evidence for no more than minor accumula-tions.These investigations provide evidence that al-though pockets of higher stress to fauna can occasionally occur,the stress on biological communities in the fjord due to residual hydrocarbons in treated ballast waters is probably low.AcknowledgementsWe thank D.Connor and C.Rutz of Alyeska Pipe-line Service Co.for their assistance in the project which was funded by a grant from the Alyeska Pipeline Service Co.We are grateful for the assistance of J.Ballek and M.Hoberg,the many students who have assisted with this project,and the crews of the M/V Valdez Star.ReferencesBlanchard,A.,Feder,H.M.,1997.Reproductive timing and nutri-tional storage cycles of Mytilus trossulus Gould,1850,in Port Valdez,Alaska,site of a marine oil terminal.Veliger40,121–130. Blanchard,A.,Feder,H.M.,2000a.Shell growth of Mytilus trossulus Gould,1850,in Port Valdez,Alaska.Veliger43,34–42. Blanchard,A.,Feder,H.M.,2000b.Distribution,reproduction,and shell growth of limpets in Port Valdez,Alaska.Veliger43,289–301. Blanchard,A.L.,Feder,H.M.,Shaw,D.G.,2002.Long-term inves-tigation of benthic fauna and the influence of treated ballast water disposal in Port Valdez,Alaska.Marine Pollution Bulletin44,367–382.Burd,B.J.,2002.Evaluation of mine tailings effects on a benthic marine infaunal community over29years.Marine Environmental Research53,481–519.Cohen,J.,1988.Statistical Power Analysis for the Behavioral Sciences.Lawrence Erlbaum Associates,Hillsdale,New Jersey.567pp. Dando,P.R.,Spiro,B.,1993.Varying nutritional dependence of the thyasirid bivalves Thyasira sarsi and T.equalis on chemoauto-trophic symbiotic bacteria,demonstrated by isotope ratios of tissue carbon and shell carbonate.Marine Ecology Progress Series92, 151–158.Fauchald,K.,Jumars,P.A.,1979.The diet of worms:a study of polychaete feeding guilds.Oceanography and Marine Biology Annual Review17,193–284.Feder,H.M.,Bryson-Schwafel,B.,1988.The intertidal zone.In:Shaw,D.G.,Hameedi,M.J.(Eds.),Environmental Studies in PortValdez,Alaska.A Basis for Management.Springer-Verlag,New York,pp.117–164.Feder,H.M.,Jewett,S.C.,1988.The subtidal benthos.In:Shaw,D.G., Hameedi,M.J.(Eds.),Environmental Studies in Port Valdez, Alaska.A Basis for Management.Springer-Verlag,New York,pp.165–202.Feder,H.M.,Matheke,G.E.M.,1980.Subtidal benthos.In:Colonell, J.M.,Stockholm,H.(Eds.),Port Valdez,Alaska:Environmental Studies1976–1979.Institute of Marine Science,University of Alaska,Fairbanks,Alaska,pp.235–318.Feder,H.M.,Mueller,G.J.,Dick,M.H.,Hawkins, D.B.,1973.Preliminary benthos survey.In:Hood,D.W.,Shiels,W.E.,Kelley,E.J.(Eds.),Environmental Studies of Port Valdez.Institute ofMarine Science Occasional Publication No.3,University of Alaska,Fairbanks,Alaska,pp.303–391.Gray,J.S.,Clarke,K.R.,Warwick,R.M.,Hobbs,G.,1990.Detection of initial effects of pollution on marine benthos:an example from the Ekofisk and Eldfisk oilfields,North Sea.Marine Ecology Progress Series66,285–299.Grehan,A.J.,1991.Demography and reproductive biology of Melinna palmata(Ampharetidae:Polychaeta)in Inner Galway Bay on the west coast of Ireland.Marine Biology109,459–467. Langston,W.J.,Burt,G.R.,Pope,N.D.,1999.Bioavailibility of metals in sediments of the Dogger Bank(Central North Sea):a mesocosm study.Estuarine,Coastal and Shelf Science48,519–540.May,S.J.,Pearson,T.H.,1995.Effects of oil-industry operations on the macrobenthos of Sullom Voe.Proceedings of the Royal Society of Edinburgh B103,69–97.Montagna,P.A.,Harper, D.E.,1996.Benthic infaunal long-term response to offshore production platforms in the Gulf of Mexico.Canadian Journal of Fisheries and Aquatic Sciences53,2567–2588. Murphy,K.R.,Myors,B.,1998.Statistical Power Analysis:A Simple and General Model for Traditional and Modern Hypothesis Tests.Lawrence Erlbaum Associates,Hillsdale,New Jersey.120pp. Olsgard,F.,Gray,J.S.,1995.A comprehensive analysis of the effects of offshore oil and gas exploration and production on the benthic communities of the Norwegian continental shelf.Marine Ecology Progress Series122,277–306.1588 A.L.Blanchard et al./Marine Pollution Bulletin46(2003)1583–1589Payne,J.R.,Driskell,W.B.,Barron,M.G.,Lees,D.C.,2001.Assessing transport and exposure pathways and potential petroleum toxicity to marine resources in Port Valdez,Alaska.Final report prepared for Prince William Sound Regional CitizenÕs Advisory Council, Payne Environmental Consultants,Inc.,Encinitas,CA,64pp.plus appendices.Available from PWSRCAC,Anchorage AK or at .Pearson,T.H.,Rosenberg,R.,1978.Macrobenthic succession in relation to organic enrichment and pollution of the marine environment.Oceanography and Marine Biology Annual Review 16,229–311.Rucker,T.L.,1983.The life history of the intertidal barnacle Balanus balanoides(L.)in Port Valdez,Alaska.M.S.Thesis,University of Alaska,Fairbanks,Alaska,271pp.Rygg, B.,1985.Distribution of species along pollution-induced diversity gradients in benthic communities in Norwegian fjords.Marine Pollution Bulletin16,469–474.Scott,P.H.,1986.A new species of Adontorhina(Bivalvia:Thyasiridae) from the Northeast Pacific with notes on Adontorhina cyclia Berry, 1947.Veliger29,149–156.Seng,L.T.,Kwong,L.Y.,Chye,H.S.,Huat,K.K.,Pheng,K.S., Hanapi,S.,Meng,W.T.,Legore,R.S.,De Ligny,W.,Tan,G.T., 1987.Effects of a crude oil terminal on tropical benthic commu-nities in Brunei.Marine Pollution Bulletin18,31–35.Shaw, D.G.,1988.Hydrocarbon accumulations.In:Shaw, D.G., Hameedi,M.J.(Eds.),Environmental studies in Port Valdez,Alaska.A basis for management.Springer-Verlag,New York,pp.243–266.Shaw,D.G.,Hameedi,M.J.(Eds.),1988.Environmental Studies in Port Valdez,Alaska:A Basis for Management.Springer-Verlag, New York.423pp.Shaw,D.G.,McIntosh,D.J.,Hoberg,M.K.,Blanchard,A.,1999.Supplemental studies of hydrocarbons in sediments of Port Valdez, Alaska1998.Final report to Alyeska Pipeline Service Co.,Institute of Marine Science,University of Alaska,Fairbanks,Alaska,53pp.Available from Environment and Natural Resources Institute, University of Alaska,7707A St.,Anchorage Alaska99501. Slack-Smith,S.M.,1994.Axinopsida serricata(Carpenter,1864),its burrowing behavior and the functional anatomy of its pallial organs(Mollusca:Thyasiridae).Veliger37,30–35.Spies,R.B.,Davis,P.H.,1979.The infaunal benthos of a natural oil seep in the Santa Barbara Channel.Marine Biology50,227–237. Steichen Jr.,D.J.,Holbrook,S.J.,Osenberg,C.W.,1996.Distribution and abundance of benthic and demersal macrofauna within a natural hydrocarbon seep.Marine Ecology Progress Series138, 71–82.Westwood,S.S.C.,Little, D.I.,Dodd,N.M.,Howells,S.E.,1987.Biological and chemical monitoring of seabed sediments at the Sullom Voe North Sea Terminal––a synthesis of data for the period 1978–1985.In:Kuiper,J.,Van den Brink,W.J.(Eds.),Fate and Effects of Oil in Marine Ecosystems.Martinus NijhoffPublishers, Dordrecht,pp.253–267.A.L.Blanchard et al./Marine Pollution Bulletin46(2003)1583–15891589。

合集下载

外文翻译原文science 2

外文翻译原文science 2

/locate/rggThe stages and duration of formation of gold mineralizationat copper-skarn deposits (Altai–Sayan folded area )I.V. Gaskov *, A.S. Borisenko, V.V. Babich, E.A. NaumovV.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences,prosp. Akad. Koptyuga 3, Novosibirsk, 630090, RussiaReceived 20 March 2009; accepted l6 November 2009AbstractGold mineralization at copper-skarn deposits (Tardanskoe, Murzinskoe, Sinyukhinskoe, Choiskoe) in the Altai–Sayan folded area is related to different hydrothermal-metasomatic formations. It was produced at 400–150 ºC in several stages spanning 5–6 Myr, which determined the diversity of its mineral assemblages. Gold mineralization associated with magnetite bodies is spatially correlated with magnesian and calcareous skarns, whereas gold mineralization in crushing zones and along fault sutures in moderate- and low-temperature hydrothermal-metasomatic rocks (propylites, beresites, serpentinites, and argillizites) is of postskarn formation. Different stages were manifested with different intensities at gold deposits. For example, the Sinyukhinskoe deposit abounds in early high-temperature mineral assemblages; the Choiskoe deposit, in low-temperature ones; and the Tardanskoe and Murzinskoe deposits are rich in both early and late gold minerals. Formation of commercial gold mineralization at different copper-skarn deposits is due to the combination of gold mineralization produced at different stages as a result of formation of intricate igneous complexes (Tannu-Ola, Ust’-Belaya, and Yugala) composed of differentiated rocks from gabbros to granites.© 2010, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.Keywords: gold mineralization; skarns, copper-skarn deposits; hydrothermal-metasomatic formationsIntroductionRecent data on the isotope geology and geochronology of rocks and ores and geological data on the ore genesis gaps proved that ore deposits formed for a much longer time than was assumed earlier (Rundkvist, 1997). This is also true for commercial gold mineralization at many Cu-skarn deposits in the Altai–Sayan folded area (ASFA).Gold-containing Cu-skarn deposits are widespread in many ore districts of the ASFA: Gorny Altai (Sinyukhinskoe,Murzinskoe, Choiskoe), Kuznetsk Alatau (Natal’evskoe, Fe-dorovskoe), Gornaya Shoria (Maisko-Lebedskoe), and Tuva (Tardanskoe, Khopto). Most of them are commercial deposits (Fig. 1).Skarn formation processes at these deposits were related to the Early and Middle Paleozoic granitoid magmatism in the Tannu-Ola (eastern Tuva), Yugala (Sinyukha, northeastern Altai), and Ust’-Belaya (northwestern Altai) intrusive com-plexes (Gusev, 2007; Shokalsky et al., 2000). Formation of commercial gold mineralization was a longer and more intricate process (Gaskov, 2008). In most part of these deposits, gold mineralization is the product of multistage ore process, which is characterized by different mineral composi-tions and spatial occurrences. Almost all these deposits bear gold mineralization spatially and genetically related to skarns and aposkarns in assemblage with magnetite and sulfides (Korobeinikov and Matsyushevskii, 1976; Korobeinikov and Zotov, 2006; Korobeinikov et al., 1987; Vakhrushev, 1972)and gold mineralization isolated from skarns and represented by sulfide-containing (pyrite, chalcopyrite, bornite, chalcocite)hydrothermal products of moderate-temperature assemblage in crushing zones (Shcherbakov, 1974). Often, the deposits also bear epithermal gold-containing assemblage with low-tem-perature sulfides, tellurides, and selenides usually developed at the final stage of mineral formation in rocks of different compositions, including sedimentary, igneous, and skarn (Gas-kov, 2008; Gaskov et al., 2005).The recently obtained ages of ore formation products and igneous rocks (Gaskov, 2008; Rudnev et al., 2004, 2006;Shokalsky et al., 2000) provide a new concept of the sequence of ore formation and its duration and relation with multiphasemagmatism.Russian Geology and Geophysics 51 (2010) 1091–1101*Corresponding author.E-mail address : gaskov@uiggm.nsc.ru (I.V. Gaskov)doi:10.1016/j.rgg.2010.0.0011068-7971/$-see front matter D 2010, IG M, Siberian Branch of the RAS.Published by E lsevier B.V .All rights reserved.V S. .Sabolev 9Let us dwell on the specific features of gold mineralization at particular deposits.Gold mineralization at Cu-skarn depositsThe Tardanskoe deposit is localized in the zone of the Kaa-Khem deep fault, in the exocontact part of the Kopto-Baisyut gabbro-diorite-plagiogranite massif (Fig. 2) (Korobe-inikov and Zotov, 2006; Korobeinikov et al., 1987). At the massif contact, Lower Cambrian volcanogenic-carbonate de-posits are transformed into magnesian and calcareous skarns described in detail earlier (Korobeinikov, 1999; Korobeinikov and Matsyushevskii, 1976; Korobeinikov et al., 1997). The skarn bodies are spatially close to aposkarn metasomatites bearing actinolite, tremolite, epidote, serpentine, chlorite, talc,quartz, carbonate, magnetite, and hematite.Gold mineralization at the deposit is of two types: (1) in skarn-magnetite rocks and (2) in metasomatites of linear crushing zones. These types have specific mineralogical and geochemical features.Gold mineralization in skarn-magnetite ores is widespread at the deposit. It is described elsewhere (Korobeinikov and Matsyushevskii, 1976; Korobeinikov and Zotov, 2006; Koro-beinikov et al., 1987; Kudryavtseva, 1969). Gold is spatially related to areas of sulfide mineralization, and its contents are in direct correlation with the amount of sulfide minerals.Gold-sulfide mineralization is extremely unevenly distributed and is localized at the sites of magnetite ores that underwent cataclasis as well as in magnetite microcracks and interstices.The total amount of sulfides (pyrite, chalcopyrite, bornite, and scarcer sphalerite, pyrrhotite, and arsenopyrite) is 1–3%. Gold occurs as fine thin (0.3–0.01 mm) native segregations. This is mainly high-fineness gold (820–990) (Fig. 3, a ) with impuri-ties of silver (up to 13.6%) and copper (up to 5.07%).According to Korobeinikov (1999) and Korobeinikov and Matsyushevskii (1976), the temperatures of formation of magnetite ores were 430–550 ºC, whereas the gold-sulfide assemblage and the hosting metasomatites (actinolite, tre-molite, serpentine, talc) were produced at 250–320 ºC (Gaskov et al., 2005; Vakhrushev, 1972).Gold mineralization in crushing zones is localized in steeply dipping linear tectonic structures of NW, NE, and NS strikes (Fig. 2), which develop after different rocks, including volcanosedimentary, igneous, and skarn ones. These zones reach several hundred meters in length and few tens of meters in width. The petrographic composition of these zones is di-verse and depends mainly on the composition of initial rocks that underwent transformation later. The rocks are metaso-matic, close in composition to propylites, listwaenites, talc-containing and sericite-quartz metasomatites, and beresite-like rocks. Almost each type of hydrothermal-metasomatic rocks is intimately associated with ore minerals. Though the total volume of these minerals does not exceed 3–5%, they are extremely diverse in composition and are extremely unevenly distributed. Along with sulfide minerals typical of Cu-skarn deposits (chalcopyrite, pyrite, bornite, chalcocite,digenite, sphalerite, galena), the mineralized zones of the deposit abound in tellurides—hessite (Ag 2Te), tellurobis-muthite (Bi 2Te 3), and tetradymite (Bi 2Te 2S),—and low-tem-perature Co and Ni sulfides and sulfoarsenides (Table 1). The latter have a variable composition and often consist of intermediate phases of continuous mineral series, e.g., allo-clasite(CoAsS)–arsenopyrite(FeAsS) or siegenite(CoNi 2S 4)–violarite(FeNi 2S 4).Gold occurs mainly as native fine thin (0.01–0.5 mm)disseminations in rock microcracks and as inclusions in pyrite,chalcopyrite, and bornite. The gold fineness varies over a broad range of values—from 440 to 820 (Fig. 3, b ). The lowest-fineness gold segregations are compositionally similar to electrum and have high contents of Ag (up to 54.78%) and Hg impurity (up to 3.65%).On the flanks of mineralized crushing zones, there is sometimes gold mineralization in low-temperature argillitized rocks of chlorite-kaolinite-carbonate-hydromica composition.This gold is of low fineness (no more than 600). The mainimpurities are Ag (20–66%) and Hg (up to 5.47%). The formation temperatures of sulfide-telluride assemblages andFig. 1. Schematic occurrence of gold-bearing Cu-skarn deposits in the Altai-Sayan folded area: 1, Murzinskoe; 2, Sinyukhinskoe; 3, Choiskoe; 4, Maisko-Lebedskoe;5, Fedorovskoe; 6, Natal’evskoe; 7, Tardanskoe; 8, Kopto.1092I.V. Gaskov et al. / Russian Geology and Geophysics 51 (2010) 1091–1101gold mineralization in metasomatites and argillitized rocks are within 200–75 ºC.The Murzinskoe deposit is localized at the contact of a small stock-like granodiorite body of the Ust’-Belaya gabbro-diorite complex (Fig. 4). In the exocontact zone, calcareous skarns composed of garnet, pyroxene, wollastonite, and mag-netite develop after the calcareous sandstones of the Murzinka Formation (D1-2). In the local zones, there are aposkarnFig. 2. Schematic geologic structure of the Tardanskoe deposit (compiled after the data of K.M. Kil’chichakov and L.V. Kopylova and our new data). 1–4, Lower Paleozoic deposits: 1, andesitic porphyrites and tuffs with siltstone and sandstone interbeds in the lower part of the Tumat-Taiga Formation (Cm 1tm 1); 2, quartz porphyrites with interbeds of andesitic porphyrites and limestones in the upper part of the Tumat-Taiga Formation (Cm 1tm 2); 3, limestones and calcareous shales of the Tapsa Formation (Cm 1tp); 4, Lower and Middle Silurian conglomerates and sandstones (S 1-2); 5, Quaternary deposits (Q IV ); 6, 7, Lower Paleozoic igneous rocks of the Tannu-Ola complex (γδO 1-2): 6, gabbro-diorite-plagiogranite formation; 7, small granite-porphyry and quartz diorite bodies; 8, calcareous and magnesian skarns; 9, hydrothermal-metasomatic rocks in mineralized crushing zones; 10, gold orebodies; 11, tectonic zones; 12, geologic boundaries.I.V. Gaskov et al. / Russian Geology and Geophysics 51 (2010) 1091–11011093Fig. 3. Variations in gold fineness in gold ores from skarn-magnetite bodies (a) and in ores from mineralized crushing zones (b) at the Tardanskoe deposit.Table 1. Mineral parageneses in gold-bearing ores produced at different stages and composition of host rocks at Au-Cu-skarn depositsDeposit Early aposkarn Au-sulfide mineralization in magnetite-skarn rocks Late Au-telluride-sulfide mineralization in superposed crushingzonesOre parageneses Host rocks Ore parageneses Host rocksTardanskoe Magneite (Fe3O4)Pyrite (FeS2)Chalcopyrite (CuFeS2)Bornite (Cu5FeS4)Sphalerite (ZnS)Pyrrhotite (FeS)Arsenopyrite (FeAsS)Gold (Au)Magnesian skarns (pyroxene +fassayite + phlogopite +pargasite + forsterite + spinel).Calcareous skarns (pyroxene +garnet + epidote +wollastonite + skapolite).Aposkarn serpentine andserpentine-chlorite rocksCobaltite (CoFe)AsSGlaucodot (Co,Fe)AsSSiegenite (CoNi2S4)Violarite (FeNi2S4)Hessite (Ag2Te)Gold (Au)Propylites, listvaenites, talc-serpentine-containing andsericite-quartz metasomatites,and argillitized rocksMurzinskoe Magnetite (Fe3O4)Chalcopyrite (CuFeS2)Pyrite (FeS2)Bornite (Cu5FeS4)Sphalerite (ZnS)Galena (PbS)FahloreArsenopyrite (FeAsS)Clinobisvanite (BiVO4)Gold (Au)Calcareous skarns (garnet +pyroxene + wollastonite).Aposkarn metasomatic rocks(quartz + epidote + chlorite +actinolite)Cinnabar (HgS)Metacinnabarite (HgS)Bismuthine (Bi2S3)Aikinite (CuPbBiS3)Emplectite (CuBiS2)Berryite [Pb2(Cu,Ag)3Bi5S11]Naumannite (Ag2Se)Polybasite (Ag16Sb2S11)Barite (BaSO4)Gold (Au)Quartz and quartz-carbonateveins, near-vein metasomatitesof quartz-chlorite-carbonatecomposition, and argillitizedrocksSinyukhinskoe Magnetite (Fe3O4)Pyrite (FeS2)Chalcopyrite (CuFeS2)Bornite (Cu5FeS4)Chalcocite (Cu2S)Sphalerite (ZnS)Pyrrhotite (FeS)Cubanite (CuFe2S3)Gold (Au)Wollastonite, garnet-wollastonite, garnet-pyroxeneand pyroxene skarns, andaposkarn metasomatic rocks(chlorite + actinolite + calcite)Tetradymite (Bi2TeS)Siegenite (CoNi2S4)Cobaltite ((CoNiFe)AsS)Melonite (NiTe2)Wittichenite (Cu3BiS3)Hessite (Ag2Te)Petzite (AuAg3Te2)Altaite (PbTe)Clausthalite (PbSe)Gold (Au)Local zones of actinolite-chlorite-calcite-quartzcompositionChoiskoe Magnetite (Fe3O4)Pyrite (FeS2)Chalcopyrite (CuFeS2)Gold (Au)Garnet, garnet-pyroxene,garnet-wollastonite, andpyroxene-epidote skarnsTetradymite (BiTe2S)Ingodite (Bi2TeS)Joseite (Bi4TeS2)Hedleyite (Bi2Te)Tellurobismuthite (Bi2Te3)Bismuthite (Bi2S3),Native bismuth (Bi)Gold (Au)Quartz and quartz-carbonateveins and quartz-carbonate-chlorite metasomatites1094I.V. Gaskov et al. / Russian Geology and Geophysics 51 (2010) 1091–1101metasomatic rocks consisting of quartz, epidote, calcite,chlorite, actinolite, and, more seldom, tourmaline, apatite, and rodonite.Gold mineralization at the Murzinskoe deposit was earlier ascribed to gold-skarn type. But recent data have shown that only a minor part of the deposit ores — scarce postskarn sulfide mineralization spatially associated with skarn-magnet-ite bodies—can be referred to this type. Most of the commer-cial ores occur in mineralized crushing zones. They form gold-sulfide mineralization in quartz and quartz-carbonate veins and near-vein metasomatites in a 300–400 m thick zone stretching in the N-NW direction for more than 3 km (Fig. 4).The crust of weathering widespread at the deposit contains hypergene copper minerals: malachite, chrysocolla, azurite,chalcocite, coveline, and high-fineness gold.Gold-sulfide mineralization spatially associated with skarn-magnetite bodies is superposed on skarn rocks. It was produced either at the regressive stage of the skarn formation or at the postskarn hydrothermal-metasomatic stage and was accompanied by the formation of moderate- and low-tempera-ture metasomatic minerals—chlorite, actinolite, epidote, and quartz. Sulfide mineralization is unevenly distributed and occurs as veinlet-disseminated chalcopyrite, pyrite, bornite,and sphalerite. It amounts to few percent. Gold occurs as fine thin (0.5–0.01 mm) native segregations. It is mainly of high fineness (840–994) (Fig. 5, a ).In crushing zones (Fig. 4), gold mineralization was found in quartz-carbonate-sulfide veinlets and veins in hydrothermal-metasomatic rocks of quartz-chlorite-carbonate composition with kaolinite, hydromica, and adularia (argillizite formation)developing after different rocks—skarns, hornfelses, shales,siltstones, and limestones,—often beyond skarning and horn-felsing zones. The quartz veins are 0.1 to 2.0 m (on average,0.4 m) thick, of N-S strike and eastern dip. In contrast to the gold-skarn-magnetite type, this mineralization is of more complex composition. In addition to minerals typical of skarn deposits (chalcopyrite, pyrite, bornite, sphalerite, and galena),it includes fahlore, arsenopyrite (FeAsS), cinnabar (HgS),metacinnabarite (HgS), bismuthine (Bi 2S 3), aikinite (CuPb BiS 3), emplectite (CuBiS 2), berryite [Pb 2(Cu,Ag)3Bi 5S 11],naumannite (Ag 2Se), polybasite (Ag 16Sb 2S 11), scheelite (Ca 3WO 4), hematite (Fe 2O 3), clinobisvanite (BiVO 4), bariteFig. 4. Schematic geologic structure of the Murzinskoe deposit. 1, mica-sili-ceous shales (O 1); 2, sandstones, siltstones, and aleuropelites (S 1); 3, terri-genous-carbonate deposits (D 1-2): a , conglomerates, b , limestones, c , sand-stones; 4, granodiorites of the Ust’-Belaya complex (D 3); 5, altered rocks and metasomatites: a , hornfelses, b , skarns, c , quartz-tourmaline metasomatites;6, mineralized crushing zones; 7, faults: a , established, b , predicted; 8, other types of mineralization: a , Murzinka-3 (Au), b, skarn Fe.Fig. 5. Variations in the fineness of gold associated with skarn-magnetite bodies (a ) and gold from ores of mineralized crushing zones (b ) at the Murzin-skoe deposit.I.V. Gaskov et al. / Russian Geology and Geophysics 51 (2010) 1091–11011095(BaSO 4), and gold (Table 1). The content of gold in the ores varies over a broad range of values, from 0.1 to 232 ppm.This gold occurs as fine (<0.1 mm) thin segregations in assemblage with sulfides. Its fineness also greatly varies (640–840), but, compared with the first type of ores, low-fine-ness gold prevails here (Fig. 5, b ).The presence of cinnabar, sulfides and sulfosalts of Bi, Se,and Sb, and barite, predominance of low-fineness gold and electrum, and low-temperature wallrock alteration (formation of kaolinite, hydromica, and adularia) differ these ores from earlier formed ores in skarn-magnetite bodies. The gap between the skarn and ore formation processes is evidenced from the presence of basite dikes cutting the skarns, which bear superposed gold mineralization of this type. At the same time, the presence of gold–cinnabar intergrowths and fine dissemination of gold in cinnabar, presence of Hg-minerals (cinnabar, Hg-sphalerite, saucovite) in the ores, and high contents of As, Sb, and Ti (typical elements of many Au-Hg deposits) permit this mineralization to be referred to as epithermal Au-Hg type (Borisenko et al., 2006). Thermometric studies showed that the homogenization temperatures of fluid inclusions in quartz veins in the northern and central parts ofthe mineralized zone are 215–200 ºC and decrease to 160–130 ºC in the southern part.Fig. 6. Schematic geologic structure of the Sinyukhinskoe deposit (compiled by Gusev (2007) and supplemented by our data). 1, loose Quaternary deposits; 2–6, rocksof the Choya (O 1cs), Elanda (C−2-3el), Ust’-Sema (C −2us), and Upper Ynyrga (C −2vy) Formations: 2, conglomerates, 3, siltstones, 4, sandstones, 5, limestones,6, andesite-basaltic porphyrites; 7–9, rocks of the Yugala (Sinyukha) complex: 7, granites and granodiorites of the early phase (γδD 2-3), 8, granites of the late phase (γD 2-3), 9, dolerite and gabbro-dolerite dikes; 10, plagiogranites of the Sarakoksha complex (ν C −2); 11, skarns; 12, sites with gold mineralization (1, Pervyi Rudnyi (First Ore), 2, Zapadnyi (Western), 3, Faifanov, 4, West Faifanov, 5, Ynyrga, 6, Nizhnii (Lower), 7, Tushkenek, 9, Gorbunov); 13, faults.1096I.V. Gaskov et al. / Russian Geology and Geophysics 51 (2010) 1091–1101The Sinyukhinskoe deposit is localized in northeastern Altai, at the contact of the large (600 km 2) complex Sarakok-sha pluton and Cambrian volcanosedimentary strata of the Ust’-Sema Formation (Shcherbakov, 1967; Vakhrushev, 1972)(Fig. 6). According to Shokalsky et al. (2000) and Gusev (2007), this massif includes the Lower Cambrian Sarakoksha diorite-tonalite-plagiogranite complex and Lower Devonian Yugala gabbro-diorite-granite complex (Sinyukha complex (Gusev, 2003)). It is in the latter complex that the commercial mineralization of the Sinyukha ore field is localized. In the contact zone of the Sinyukha massif, skarns of different compositions are developed in horizons of carbonate rocks and tuffs. Wollastonite and garnet-wollastonite varieties are the most widespread, and garnet-pyroxene and pyroxene ones are scarcer. Near the contact with basic effusive bodies, small magnetite orebodies have been revealed among garnet-py-roxene skarns.Gold mineralization occurs mainly among wollastonite,garnet-wollastonite, and pyroxene-wollastonite skarns and is intimately associated with an assemblage of sulfide minerals.The latter are dominated by bornite, chalcocite, chalcopyrite,and pyrite, which compose ore zones in these rocks and are present in the form of nest-disseminations and stockworks. In local zones of actinolite-chlorite-calcite-quartz composition we found minor amounts of sphalerite, pyrrhotite, cubanite, and tetradymite. There are also occasional findings of rare miner-als, such as siegenite (CoNi 2S 4), cobaltite ((CoNiFe)AsS),melonite (NiTe 2), wittichenite (Cu 3BiS 3), gessite (Ag 2Te),petzite (AuAg 3Te 2), altaite (PbTe), and clausthalite (PbSe)(Table 1). The total content of sulfides does not exceed 5–10%. The sulfides are extremely unevenly distributed—from occasional dissemination to densely disseminated, almost massive ores. The composition of sulfide mineralization slightly changes with depth: Gold-chalcocite-bornite assem-blage is changed by gold-chalcopyrite one. The accumulation of gold-sulfide mineralization was accompanied by the hy-drothermal-metasomatic alteration of the host skarns with the formation of actinolite, chlorite, and calcite near ore veins and nests. Magnetite ores are poorer in gold, and sulfide-free rocks(marbles and diorite-porphyry and granite-porphyry dikes)virtually lack it.Fig. 7. Variations in gold fineness in ores from the Sinyukhinskoe deposit.Fig. 8. Schematic geologic structure of the Choiskoe deposit (compiled by Gusev and Gusev (1998) and supplemented by our data). 1–5, rocks of the Ishpa (O 1is) andTandosha (C−2-3td) Formations: 1, conglomerates, 2, siltstones, 3, sandstones, 4, limestones, 5, felsic tuffs; 6–7, granitoids of the Yugala complex: 6, granites and granodiorites of the early phase (γδD 2-3), 7, leucocratic granites of the late phase (γD 2-3); 8, granite-porphyry, diorite, and lamprophyre dikes (γδD 2-3); 9, skarns;10, gold mineralization occurrences (1, occurrence of the Central skarn deposit, 2, Pikhtovyi, 3, Smorodinovyi); 11, faults.I.V. Gaskov et al. / Russian Geology and Geophysics 51 (2010) 1091–11011097Gold often occurs in ores as native segregations in the form of hooks, fine wires, lumps, and sheets intimately intergrown with bornite, chalcocite, and chalcopyrite. Sometimes, native gold segregations are observed as fine inclusions in cracks and interstices of skarn minerals, most often, wollastonite. These gold particles are mainly no larger than hundredths of millimeter. The gold of primary ores of the Sinyukhinskoe deposit is of high fineness varying over a narrow range of values (911–964) (Fig. 7). The fineness of gold decreases to 860–870 only in its parageneses with tellurides, selenides, and rare sulfide minerals (Roslyakova et al., 1999). The main impurities in gold are silver (up to 19%) and copper (up to 1.7%). The content of Hg does not exceed 0.1%. By the formation conditions, these ores are postskarn hydrothermal,with their deposition temperatures not exceeding 350 ºC (Roslyakova et al., 1999; Shcherbakov, 1972).The Choiskoe deposit is localized 20 km northeast of the Sinyukha ore field, in the zone of contact between the Upper Cambrian terrigenous-carbonate deposits of the Ishpa Forma-tion and the Choya granitoid massif referred to the Lower Devonian Yugala gabbro-diorite-granite complex (Fig. 8). The Choya granitoid massif is small at the surface (1 × 5 km) and extends from west to east, tracing the Choya fault (Gusev,2007). The deposit abounds in dikes of dolerite porphyrites,diorites, and granite-porphyry and in rocks of the lamprophyre series—kersantites, minette, and spessartites. The zone of contact between the granitoids of the Choya massif and the horizons of limestones and terrigenous-carbonate rocks is composed of skarns, which form linear zones extending in the NE direction, like the other rocks. Most bodies are of persistent thickness, ~100 m. By composition, the skarn bodies are divided into zones of garnet, garnet-pyroxene, pyroxene,garnet-wollastonite, and pyroxene-epidote skarns. In the skarn zones and near lamprophyre bodies, poor scheelite-molybde-nite mineralization in quartz veins was established (Gusev,1998).Gold mineralization at the deposit occurs in linear tectonic zones and is not spatially associated with skarns. It develops as quartz veins and quartz-carbonate and quartz-carbonate-chlorite veinlets and nests with gold-sulfide mineralization in crushing and brecciation zones in both the skarns and the granitoids of the Choya massif (Fig. 8).The mineral composition of these objects is nearly the same—gold-sulfide and gold-telluride parageneses. A numberof rare tellurides have been revealed among the Choya deposit ores: tetradymite (BiTe 2S), ingodite (Bi 2TeS), joseite (Bi 4TeS 2), hedleyite (Bi 2Te), tellurobismuthite (Bi 2Te 3), bis-muthine (Bi 2S 3), and native bismuth (Table 1). Magnetite,pyrite, and chalcopyrite, typical minerals of Cu-skarn deposits,are extremely scarce here. The total content of sulfides does not exceed few percent. They occur mainly as fine thin dissemination and do not form large accumulations and nests.Gold in the Choya deposit ores occurs as fine inclusions in sulfide and telluride minerals in quartz veinlets and as intergrowths with ore minerals. The gold particles are hun-dredths and tenths of millimeter in size. By chemical compo-sition, the gold is divided into two groups: medium-fineness (843–880) and high-fineness (940–959); the latter is probably of exogenous nature (Fig. 9). The gold contains Ag (3–12.5 wt.%) and Hg (0–0.48 wt.%) impurities and Cu traces.The thermometric studies showed that homogenization of primary gas-liquid inclusions into liquid proceeds at 126–150 ºC in quartz and at 105–128 ºC in calcite from ore-bear-ing veins.The sequence and duration of formation of gold mineralization and its correlation with magmatism As seen from the above data, gold mineralization at all considered Cu-skarn deposits has a complex multistage for-mation history. But the same stages at different deposits ran with different intensities. For example, at the Sinyukhinskoe deposit, mainly early high-temperature mineral assemblages are widespread, whereas at the Choiskoe deposit, low-tempera-ture ones. The Tardanskoe and Murzinskoe deposits bear both early and late minerals. To elucidate the peculiarities of gold-ore formation, establish the correlation between different types of gold mineralization and magmatic activity, and evaluate the duration of ore formation, we performed Ar-Ar and U-Pb dating of different mineralization and igneous rocks from the Tardanskoe and Murzinskoe deposits.Our investigations have shown that the formation of gold mineralization at the Tardanskoe deposit lasted for a longer time than it was supposed earlier. Skarn mineralization formed at the contact of diorites with carbonate rocks as a result of the intrusion of the Kopto-Baisyut massif. Ar-Ar biotite dating of the massif yielded an age of 485.7 ± 4.4 Ma corresponding to the Early Ordovician (Table 2). The skarns at the massif contact as well as magnetite ores and gold-sulfide mineraliza-tion (pyrite, chalcopyrite, pyrrhotite, bornite, gold) spatially and genetically associated with skarn-magnetite bodies are of similar age. Gold was deposited together with sulfides, as evidenced from the direct correlation between the contents of gold and sulfides (especially chalcopyrite) and from gold inclusions in the sulfides. The formation of skarn and aposkarn mineralization was followed (with some temporal gap) by the intrusion of dike and stock-like small granitoid bodies, which is indicated by their cutting of the sulfide-bearing skarn and magnetite bodies. Ar-Ar dating of these granite bodies yielded an age of 484.2 ±4.3 Ma (Table 2).Fig. 9. Variations in gold fineness in ores from the Choiskoe deposit.1098I.V. Gaskov et al. / Russian Geology and Geophysics 51 (2010) 1091–1101。

医学英语期末试题及答案

医学英语期末试题及答案

医学英语期末试题及答案一、选择题（每题2分，共20分）1. Which of the following is NOT a type of cancer?A. MelanomaB. LeukemiaC. CarcinomaD. Fibroma2. The term "cardiology" refers to the study of:A. The heartB. The lungsC. The brainD. The kidneys3. What is the medical term for inflammation of the stomach lining?A. GastritisB. BronchitisC. HepatitisD. Nephritis4. The abbreviation "MRI" stands for:A. Magnetic Resonance ImagingB. Medical Records IndexC. Myocardial Resection ImagingD. Maximum Respiratory Index5. Which hormone is responsible for the regulation of bloodsugar levels?A. InsulinB. ThyroxineC. CortisolD. Estrogen6. The process of healing a broken bone is called:A. FractureB. OsteogenesisC. OsteoporosisD. Osteolysis7. A "diagnosis" in medicine is:A. The treatment of a diseaseB. The identification of a diseaseC. The prevention of a diseaseD. The cause of a disease8. What is the medical term for a surgical incision into the chest cavity?A. LaparotomyB. ThoracotomyC. CraniotomyD. Hysterectomy9. The abbreviation "HIV" stands for:A. Human Influenza VirusB. Hepatitis Infection VirusC. Human Immunodeficiency VirusD. Hereditary Immune Virus10. A "pathogen" is:A. A type of medicationB. A disease-causing microorganismC. A symptom of a diseaseD. A preventive measure against disease二、填空题（每空1分，共10分）1. The medical term for the surgical removal of the appendix is __________.2. The study of the nervous system is known as __________.3. A condition characterized by high levels of blood sugar is called __________.4. The process of the body fighting off pathogens is known as __________.5. The abbreviation for the common cold is __________.6. The medical term for inflammation of the heart muscle is __________.7. The medical specialty dealing with the urinary system is __________.8. A person who specializes in the study and treatment of cancer is called an __________.9. The abbreviation for the human papillomavirus is__________.10. A medical condition where the body's immune system attacks its own tissues is known as __________.三、简答题（每题5分，共20分）1. Explain the difference between a virus and a bacterium.2. Describe the function of the thyroid gland.3. What is the purpose of vaccination?4. Define the term "epidemic" and give an example.四、翻译题（每题5分，共20分）1. 翻译以下医学术语："急性阑尾炎"2. 翻译以下医学术语："慢性支气管炎"3. 翻译以下医学术语："高血压"4. 翻译以下医学术语："糖尿病"五、病例分析题（每题10分，共20分）1. 患者，男性，45岁，主诉胸痛，呼吸困难。

病理学名词解释及问答题大全（带答案）PDF

病理学名词解释及问答题大全（带答案）PDF

第一章、第二章三、名词解释 1. atrophy 2. adaptation 3. hypertrophy 4. hyperplasia 5. metaplasis 6. degeneration 7. fat necrosis 8. fatty infiltration 9. hyaline change 10. amyloidosis 11. mucoid degeneration 12. pathologic pigmentation 13. lipofuscin 14. melanin 15. pathologic calcification 16. necrosis 17. pyknosis 18. karyorrhexis 19. karyolysis 20. lytic necrosis 21. coagulative necrosis 22. caseous necrosis 23. Russells body 24. gangrene 25. ulcer 26. erosion 27. fistula 28. cavity 29. organization 30. encapisulation 31. sinus 六、问答题1. 病理学的学科内容性质及地位如何2. 病理学的常用研究方法有哪些各有什么特点3. 简述细胞、组织损伤的常见形态学改变及其特点。

4. 简述肉芽组织的组成及其功能。

5. 举例说明萎缩的器官其形态与功能的改变。

6. 影响创伤愈合的局部和整体因素有哪些7. 细胞坏死和细胞凋亡的区别8. 判断组织坏死的病理学标准是什么9. 凝固性坏死和干酪样坏死的区别与联系。

10. 心脏、肝脏和肾脏发生了空泡样变性怎样确定其病变性质11. 比较干性坏疽和湿性坏疽之病变。

12. 心肌脂肪变性和心肌脂肪浸润的区别13. 简述CPC与CCP在病理学中的地位与意义。

14. 举例说明化生的本质与意义。

植物病虫害绿色防控技术教学课件(含英文)：稻曲病绿色防控(双语)

植物病虫害绿色防控技术教学课件(含英文)：稻曲病绿色防控(双语)

在水稻孕穗至抽穗期，连续低温、多雨、日照少，有利于发病。长期灌水过深，田水落干过迟病害 发生严重。施氮肥过量，尤其在穗期追施氮肥过多的田块发病加重。
Rice booting and heading stages meeting with periodic low temperatures, rain, and little sunshine are conducive to the disease. The severity of the disease is most likely to occur in long-term and too-deep irrigation and too late dried bed soil in the field water. Excessive application of nitrogen fertilizer, especially in fields with excessive application of topdressing of nitrogen fertilizer at the heading stage aggravates the disease.
水稻病虫害绿色防控 Green Prevention and Control of Rice Diseases and Pests
三 稻曲病绿色防控 Green Prevention and Control of Rice False Smut
（四）防治措施 Control Measures
（1）选育和种植抗病品种：选用抗病品种是防治稻曲病最经济有效的方法。如在重庆 市区域内的主栽品种中，准两优527、K优88、金优725、岗优615、D优162、汕优149 等品种病穗率、病粒率都较低，说明这些品种具有一定的抗病能力。