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60 GEOGRAPHY 1 palaeoclimate. isotopes; syngenetic tabular massive ground ice;stable oftheHolocene.cooler periods to theendofPleistocene (MIS2)andduring formation. Icewedges formation corresponds andgroundepigenetically withcryotexture ice sedimentswereMIS1. Marine frozen syn-and changed to continentalconditionsinMIS2and time(MIS3) thelate Kargino conditions during sedimentation Holocene sediments. Marine environments andfreezing ofLate Pleistocene- and palaeogeographical reconstructionofthe Gydan Bays enableusto refine thestratigraphy from transects geocryological and and otheranalyses. Several stratigraphic- mineralogical, geochemical, oxygen isotopic, spore andpollen,foraminifera, grain-size, Western Taymyr andpresents theresults of depositsof ground iceandQuaternary presents thenewanalyticalstudiesof methods. and geocryological The paper studied usingcomprehensive stratigraphic 5 4 3 2 Irina D. Streletskaya Estonia; e-mail: [email protected] Estonia; e-mail: Geology, Tallinn Technical University, Estonia, 5,Ehitjate Street. 19086 Tallinn. [email protected] e-mail: [email protected], [email protected]: *Corresponding author [email protected] 1,Russia,e-mail: Gory Leninskie Gleb E. Oblogov KEY WORDS: ABSTRACT. COAST (NW , RUSSIA) FROM PERMAFROST SEQUENCES AT THE PALAEOENVIRONMENTAL RECORDS PLEISTOCENE-HOLOCENE Research Laboratory of Geochronology of the Quaternary Period, ofGeochronologyResearch oftheQuaternary Laboratory of Institute St. Petersburg State University, 199034,St.Petersburg, Universitetskaya nab. 7–9, VNIIOkeangeologia, 190121St. Petersburg pr. Angliyskii 1,Russia; SBRAS,625000, Institute Cryosphere Earth Tyumen, p/obox 1230,Russia; Lomonosov Moscow State University, ofGeography, Department 119991,Moscow, The Kara Seacoasts wereThe Kara

Arctic coasts;permafrost; 2 , Anatoly N.Molodkov polygonal icewedges; 1* , Еvgeny А.Gusev 5 3,4 and surfaces ofwatersheds are completed and surfaces slope processes. onslopes Geological sections and thermoabrasion, by thermodenudation, high icecontent and are constantlymodified composed offinegrained sedimentswith low ground temperatures. The coastsare conditions, continuouspermafrost, and regions are bysevere characterized climatic The Yenisey GulfandGydan Peninsula sediments oftheNorth. depositsandground ice study ofQuaternary the needfor amore detailed comprehensive Pleistocene indicate intheMiddle-Late Siberia models ofdevelopment ofnorthern West incurrently existing 2012]. Suchcontradictions glaciation around 90kBP[GusevandMolodkov, theentire during MIS5,whichexcludes the conditionsinthelowermarine Yenisey River [Svendsen atal., 2004]. There is evidence of of of large icesheet inthenorth West Siberia polygonal ground iceexclude thepresence present ones, of andwidedistribution in climaticconditionssimilarorcolderthan Accumulation ofLate Pleistocene sediments INTRODUCTION , Alexander A. Vasiliev 2 , 60.039:22:20 9:22:20 26.08.2013 ggi313.indd 61 i 3 1 3 . i n d d

6 features inthemaingeologic andgenetic ofpermafrost allowed detailcharacterization atfive sitesof more which than30km ofcoastalcliffs withatotalsections length includedinvestigationThe scopeofwork of Pleistocene andHolocene. conditions onthe Yenisey inthe North paleogeographic reconstructionofthe stratigraphy andrevising the Quaternary sedimentsallows by datingofQuaternary application ofnewtechniques supported of ground iceandthesedimentswith 2012]. Generalizationofanalyticalstudies etal., etal.,Streletskaya 2011;Streletskaya al., and 2007;Streletskaya Vasiliev, 2009; etal., etRomanenko 2001;Streletskaya coasts [Danilov, 1969;Oblogo Sea permafrost exposures along theKara based oncomprehensive research of ronment intheLate Pleistocene-Holocene phic conditionsandsedimentationenvi- rein wasreconstructionofthepaleogeogra- presented ofthework mainobjective he- The reconstructions. information andare usedinpaleoclimatic paleogeographic They provide important SPIW and TMGI have uniquenaturalfeatures. orintrasedimentalinorigin. as buried atal.,Streletskaya 2009]. TMGI are classified and Tarnogradsky, 1986;Solomatin,1982; debate [Danilov, 1969,1978;Kaplyanskaya ofthe enclosing clay depositsisasubject ice. The genesisofthe TMGI andthe ice content around 100%)andsegregation (large tabularicebodieswithvolumetric tabular massive ground icebodies(TMGI) sedimentscontain groundSaline marine ice: 2012]. andStreletskaya, 100 m[Matyukhin ofmore than sediments withathickness Quaternary salinemarine mostly offine-grain weatheringandare composed cryogenic Parental bedrocks are to subjected intense ofthe second alluvialterrace Yenisey River. ofthe ofthesection Thick SPIWispart syngenetic polygonal icewedges (SPIW). by alayer ofcontinentalsedimentswith 1 MATERIAL AND METHODS v etal., 2012; wood fragments, andboneswere for picked ostracodes, spores andpollen,diatoms. Peat, biostratigraphic indicators –foraminifers, for theinvestigation oforganic matter and of30cm–1mfor grain-sizeat intervals and sediments fromwere thesections sampled and macro faunasinthesediments. The content, andpalynological analysesofmicro of water-soluble salts, organic carbon andcomposition composition, total salinity size andmineralogical of icecontent, particle included datingofsediments, determination Complex field andanalyticalinvestigation (Fig.is about250km 1). points(CapeSopochnayaand eastern Karga) mounth) River the western (Ery-Maretayakha andthedistancebetween is about150km, points(CapeSopochnaya Karga) southern (villageDikson)and the northern between complexes. Quaternary The distance Petersburg State University. Allradiocarbon Russian Academy of SciencesandSaint oftheof GeologyandMineralogy oftheSobolevInstitute at thelaboratories (AMS) wasdetermined mass spectrometry datingusingtheaccelerator Radiocarbon preparation. mill laboratory “Retsch” (Germany) sample werecontents outusingthe (OCC) carried oforganicThe determination carbon St. Petersburg, Russia. in of the World (VNIIOceangeologiya) Ocean Resources forInstitute GeologyandMineral ofAll-RussianResearch and Geochemistry ofLithology methods intheLaboratory analyses were usingstandard conducted water extract) aqueous migrate (Makarov: and pipette analysis. The chemistry: Grain size bysieving wasdetermined percentage (wt%). sample, expressed asweightof thedry weight ofthefrozen sampleto theweight immediately thawing after byrelating the the gravimetric icecontent wasestimated Along withrecording sedimentdescriptions, 14 C agedetermination. 226.08.2013 9:22:21 6

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6 62 GEOGRAPHY 2 ground ice( The chemicalandisotope compositionsof uncalibrated ages. dates through thispaperare as reported Meteoric Meteoric Water Line(GMWL)[Craig, 1961]. The are generallydisplayed relative to theGlobal 2000). Stableisotope dataoficeand water for 1s errorsinternal are <0.8%for The Standard Ocean Mean Water (V-SMOW). relative to standard theinternational Vienna values give therespective permil-difference Research, Research UnitPotsdam. Alfred Wegener for Institute Polar andMarine ofthe attheIsotopedetermined Laboratory isotope compositionofground icewas wedges and intrasedimentalice. The stable in samplesofmelted water from theice- δ 18 Fig. 1. Location of the study area in Northern Siberia in the and Gydan Bay. Gydan and Gulf Yenisey the in Siberia Northern in area study the of 1.Fig. Location O for allmeasurements etal., (Meyer δ

18 O and δ D) were determined D)were determined δ The sites are described in the text the in described are sites The D and <0.1% D and<0.1% δ D and δ 18 O deuterium excessdeuterium (d= (Fig. 3A)were analyzed byinfrared optically ofthecliff part Sands from thenorthern and Streletskaya Vasiliev, 2009]. Fig. atal., 3)[Streletskaya 2007,2009,2011, coast onCapeSopochnaya Karga segment ofthe along 6km Yenisey Gulf were previously studiedinseveral exposures as sedimentswithnovisibleiceinclusions ning large inclusionsofground iceas well Pleistocene andHolocenesedimentscontai- The exposure nearSopochnaya Karga Cape processes. fractionation equilibrium by Dansgaard [1964]isanindicator for non- THE STUDY SITES AND RESULTS δ D –8 δ 18 O) introduced O) introduced

(Fig. 2and 226.08.2013 9:22:21 6 . 0 8 . 2 0 1 3

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6 The rangeof etal.,optimum [Streletskaya 2009](Fig. 3C). (GIN 13055),whichcorresponds to theclimatic is sho wed thattheageoforganic horizons peatsamples datingoftwo Radiocarbon al., 2011]. et al.,1770-107) [Streletskaya 2009;Gusevet (RLQG (RLQG 1769-107)and117,7±10,0KA samplesfromin112,5±9,6 KA two thissection The results allowed usto theageof determine stimulated luminescencemethod(IR-OSL). –19.0 to –140.6 and -177 rather constantandis-23 The stableisotope content in TMGI is 13.0 excess isfrom 4.5 thawed and later refrozen sandy-clay The landslidebodyrepresents partially ofthe alluvial terrace Yenisei (Figure River 3D). wide, whichcovers thefragment ofthesecond from thelandslideof22mheightand200 The scaleoftheprocesses canbeinferred 3 7320 ± 130 yrs(GIN13056)and8050 ± 60 yrs O O [Streletskaya atal., [Streletskaya 2011]. , andtherangeof O O for deuterium. The deuterium . excessThe deuterium isnear δ 18 Fig. 2. Location of the Sopochnaya Karga study site. August 2004. 2004. August site. study Karga Sopochnaya the of Location 2. Fig. O O inSPIWis–20.3 to 5.8 O (Photo taken from helicopter by E. Gusev) O δ D is–150.4 . for oxygen O O to to

the upper parts ofthewedges. Lower the upperparts parts SPIW upto 10mthickand2–3wide in Sandy-loams andsandshave inclusionsof the sandshave gravel inclusions(Fig. 3B). clays, withtheunderlined At thecontact (LU-6998). exposure, whichwasdated 13,770±480yrs bonewasfoundA caribou atthebaseof bypeatolderthan37,200yrs.is underlined sands 4–15mthickare found. The horizon Under thepeat,layered loams and silty 9–10,000years ago.started dating, theformation ofthepeatlayer there ispeat;according to theradiocarbon From downto oftheterrace 1m, thesurface (Fig. 3B). ofthe of thesecondterrace Yenisey River Yenisey Gulfis15–20mhigh,thelevel settlement, thecoastalexposure ofthe To from theSopochnaya Karga thenorth of theLate Pleistocene (MIS3). forest-tundra time vegetation oftheKargino from of clay sedimentsischaracteristic than 43,700yrs. Pollen complexextracted ageofthesedimentsisolder radiocarbon sediments moved downtheslope. The 226.08.2013 9:22:21 6 . 0 8 . 2 0 1 3

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Fig. 3. Schematic representation of the studied Sopochnaya Karga permafrost sequence with ground ice; sample positions, some analyses results and radiocarbon ages: 1 – clays; 2 – clays with sandy silts and sands interlayers; 3 – clay loam; 4 – sandy loam; 5 – sands; 6 – peat; 7 – talus; 8 – inclusions a) detritus, b) wood debris, c) peat debris; 9 – a) sea mollusks, b) fresh-water lacustrine shells; 10 –inclusions a) rounded pebble, b) coarse gravel; 11 –cryoturbations; 12 – polygonal wedge ice (shown outside of scale); 13 – degree of salinization of sediments, %; 14 – gravimetric water content, %; 15 – organic carbon content, %; 16 – samplinggranulometric for a) and mineralogical analysis, b) palynological analyses; 17 –boundaries: a) lithological, b) landslides; 18 – boundaries of granulometric facies, 19 – location and number sites of exposed SPWI where isotopic composition was studied; 20 – composition of oxygen (δ18O) stable isotopes of ice, ‰; 21 – genesis and age deposits; 22 – bone 226.08.2013 9:22:21 6 . 0 8 . 2 0 1 3

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6 5

Fig. 4. Schematic representation of the studied Krestianka permafrost sequence with ground ice, sample positions, some analyses results, and radiocarbon data (see legend for Fig. 3) analysis showed thatthesedimentswere The granulometric and mineralogical byiron oxidation.is visiblysupported layered sands5.5–10mthick. The layering sub-horizontally yellowish-grey well sorted 4. Undertheclay horizon, there are 38.0 ±3.0thousandyrs[Gusevetal bottom oftheprofile indicated theageof The OSLdatingofthesandlensat beaches.marine of ofmineralscharacteristic distribution from theclaysand fraction showed the analysisofthe The particle-mineralogical located at5–10masl(Fig. 4). Permian bedrocks, thetop ofwhichis depositsare the overlying Quaternary mouth,the River Near theKhrestianka River mouth nearthe KhrestiankaThe profile clay isrelatively (–18.4 heavy from inthe iceofreticulate cryostructure (Fig. 3C). The stableoxygen isotope content of oftheexposure part TMGI inthesouthern sediments intheicy content andis0.8–1.0%.Salinity clay sedimentsisindependentofpure ice The organic content in carbon 130% (TMGI). clays is32–53%andsometimeshigherthan The total gravimetric moisture content of is 70–85mmol/1%,sodium97%). content (chlorine asmarine characterized loams areupto 1.5%)and saline(salinity The by thelandslide(Fig. 3D). composition isfound inSPIWsandsburied The to 0.5–1.0 mdeep. of thewedges intrudetheclays or TMGI up –23.6 The stableoxygen isotope content in TMGI is ions, andsodiumdominate. thechlorine from 6.8 to –24.5

δ clays belowthesandsandsandy- O 18 О content ofSPIWisfrom –24.8 O whichissimilarto thecomposition

layer isless(0.2%),butamongthe O to 10.2 . excessThe deuterium is O . The sameisotope O ). ., 2011]. 226.08.2013 9:22:21 6 . 0 8 . 2 0 1 3

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Fig. 5. Schematic representation of the studied Dikson permafrost sequence with ground ice, sample positions, some analyses results, and radiocarbon data (see legend Fig. 3) Karga. Karga. The valuesof the Holocenewedges ofCapeSopochnaya lighter isotope compositioncompared to mouthhave River a near theKrestyanka The SPIWontheslopesofinterfluves lumpy loamsandclays. the gulflevel), sandstransitionto dense 5. Atthebaseofexposure (1–2mabove meadows.age withextensive oftheKazantsevo the taigavegetation type from thesandsindicatedThe pollenspectra near themouthofriver. zone ofthebeach sands intheunderwater offormation ofgravellyshow possibility sands and absenceofsiltfine-grained ofthesedimentsbysize anddensity sorting delta underwave atthebottom. action The ofthe part accumulating intheunderwater from –23.7to –21.3 composition of SPWI showed changesof composition ofSPWI ( The results oftheanalysisoxygen or plantdebris. in thesection. There are nolarge inclusions lower layer, organic matter isspread regularly thedeposits, includingtheSPIWof In thick. are very the sealevel, suggestingthatthedeposits about 10meters, butSPIWcontinuesbelow ofthedepositsis The apparent thickness near thelayers, itismicro-lenticular-layered. layers isreticulate, ataxitic, andmassive, while deposits. the between The cryostructure layered ofsyngenetic structuretypical content isover 86%)andhave arhythmically- (thetotal moisture The depositsare ice-rich (Fig.coastal scarp 5). where layers two ofSPIWpenetrate the sediments wasstudiedintheDiksonarea ofthe Quaternary The mostcomplete section The exposure village nearthe Dikson less than10 –165.0 δ 18 O) andhydrogen ( O , respectively. excess Deuterium is O (from 5.2to 9.9 O δ andfrom –180.0to 18 О and δ D) isotopic O δ ). D range 226.08.2013 9:22:22 6 . 0 8 . 2 0 1 3

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6 7

Fig. 6. Schematic representation of the structure of the coastal outcrops of the Ery-Maretayakha River mouth, the Gydan Bay (see legend Fig. 3) for itchangesfrom -24.3 lighter: composition ofthelower layer SPIWis6 the section: theupper-layerthe section: SPIWwiththe Two layers ofSPIW(Fig. 6)are exposedin 3,900 ±100yrs(GIN-2468). ageof elevation of9.3mhadaradiocarbon ± 900yrs(GIN-2469). The peatlandatthe 25,100 ±220yrs(GIN-2471),5.9m–21,900 at 4.5m–28,600±800yrs(GIN-2638),5 level: at3.5m–30,200±800yrs (GIN-2470), dating atdifferent elevationsabove thesea ofradiocarbon [1992] obtainedaseries 21,930±370 yrBP(LU-6542). Yu.K. Vasilchuk ageof sea level 7.8mhastheradiocarbon sandy depositsattheelevationsabove the and peatinterlayers. The peatinterlayer in sandy siltsare withfinesands interbedded about10mhigh, ofasurface in thesection mouth, River Closer to theEry-Maretayakha BP (LU-6534) depth of4mshowed theageof9,100±90yr datingbyplantroots from the Radiocarbon showed theageof8,500±90yrBP(LU-6535). datingbyapeatsample content. Radiocarbon that are byasubstantialice characterized deposits frozen (lacustrine-boggy) lacustrine isrepresented ofthesection by The upperpart beach (Fig.modern 6). cliffdescendingtoa thermoabrasive the withtheelevationsof10–25mand surfaces structure consistsofthermodenudational mouthwasstudied. River Maretayakha The neartheEry- The coastalcliffstructure The western coast ofthe Gydan Bay Dikson area etal., [Streletskaya 2011]. from –161 from –124 from –17.1 wedges have aheavier isotopic composition δ is from –21.7 isotopic compositionoftheupperlayer PWI and from -205.0 values from –26.8 D. Currently, thegrowing icebranchesof δ 18 O andfrom –205 O O O to -147 O to –118 to –16.2 O to –19.5 O to –150.4 O to –20.1 O ( O O δ O to –184 D). The isotopic D). The O for for O ( to -26.8 O δ δ δ ( 18 D inthe 18 δ O) and ( O D). The O and δ 18 for O O O) 226.08.2013 9:22:23 6

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Fig. 7. Schematic representation of the structure of the coastal outcrops of Cape Pakha-Sale, the Gydan Bay (see legend of Fig. 3) oxygen ( layer SPIWchangesfrom -23.6to -18.3 10 m. The isotopic compositionoftheupper- of 2.5montop andtheheightofmore than and thelarge lower-layer SPIWwiththewidth width of for change withdepthandis–24.6...–22.6 hydrogen stableisotopes intheicedoesnot and sandysilts. The content ofoxygen and pointGD1)penetrate sands (observation of4.5m wedges withtheaverage thickness Here, thin(withthewidthofupto 0.4m)ice thawed.cropped byslopeprocesses orpartly ispossiblethatitwas It part. southern intheoutcrop’sLarge SPIWisnotobserved changes from 9to 12 hydrogen ( surface withthepolygon sideof18–55m. surface wedges form onthe apolygonal network deposits includetheSPIWcomplex. The ice of 83%silt-sized particles. The lacustrine 15mhigh.Sandysiltsconsist and surfaces depression form theslopesofathermokarst sandy siltsthat into abandoflightdusty deposits lensisembeddedalongthestrike (LU 6541)atthedepthof6m. The lacustrine is 5,280±160yrs(LU 6540)andis8,030±80yrs The ageofwood inclusionsatthedepthof2.6m with organic matter. 1200 mcontainslayered sandysiltssaturated of4–6mandthevisiblelength thickness depositswiththeA lensoflacustrine scattered alongthebeach. that waswashedoutofthecoastalcliffs is detritus. Alarge amountofbonedebris Holocene continentalsedimentswithplant deposits are bytheLate overlaid Pleistocene- the heightof15–20m.More ancientmarine depositsoutcropaleuriс incoastalcliffs with Here, sand- andcoastal-marine marine Sale wasanotherarea oftheresearch (Fig. 7). nearCapePakha-The coastalcliffstructure The eastern coast ofthe Gydan Bay excessdeuterium doesnotexceed 6–7 δ 18 О and–193.1...–176.5 δ 1.2 m on top and the height of 3.6 m 1.2 montop andtheheightof3.6m 18 δ О) andfrom -179.9to -134.3 D); the deuterium excess (d excess) excessD); thedeuterium (dexcess) O . O for δ O O D; the O 226.08.2013 9:22:23 6 O for for

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6 ( isotopic composition is–19.1 on top andthelengthof2–5m. The SPWI haveIce-wedges thewidthof20–50cm 10-9 thousand years ago led to thermokarst 10-9 thousandyears agoledto thermokarst thousand years ago. around Climate warming (MIS2) withsedimentationending about10 theLateaccumulated Pleistocene during of thelower layer oftheDiksonexposure mouth andthesedimentsincludingSPIW River Gydan Bay neartheEry-Maretayakha the Yenisey River, thecoastalcliffof ofThe sedimentsofthesecondterrace freshwater alluvialsandsandsandyloams. lower hypsometrical levels composedof salinesedimentsto theyoungerof marine composed landslides from highersurfaces can beexplainedbymovement oflarge in theprofile (Fig. ofSopochnaya Karga 3D) [Bolshiyanov, 2006].Inversion inthedates etal.,Island [Streletskaya 2012],and etal., 1986],Sibiryakova [Trofimov peat accumulationoccurred attheGydan thesameperiod, the age;during the Kargino indicates age ofpeatnearSopochnaya Karga Gusev andMolodkov, 2012]. The radiocarbon profile [Gusevetal., 2011;Nazarov, 2011; dated byIROSLare located lower inthe sands (MIS5) marine because theKazantsevo (MIS3), be compared period withtheKargino infrared OSL. AMS datesThe radiocarbon can were AMS dated and usingradiocarbon Seacoast Holocene sedimentsoftheKara The investigated Late Pleistocene and existence oftalikunderthelake. pointsto the cryostructure post-cryogenic horizon witharelatively lowice content and accumulated attheendoffilling. A ice content. The coarsersandsediments sandysiltswithhigh coasts formed bydusty ofthe thedestruction during the lake beginning oftheHolocene. They gotinto thefirststagein accumulated during stages.occurred intwo The deposits depression The fillingofthethermokarst excessdeuterium (dexcess) is7.2 9 DISCUSSION δ 18 О) and–146.2 O

for hydrogen ( O for oxygen O δ . D); the in the pre-Kargino (MIS3)timeunder in thepre-Kargino which meansthattheirformation occurred Peat formation overlays oftheKargino TMGI, of sedimentfreezing searegression. after structure indicates epigenetictype cryogenic in forest-tundra alongthecoasts. The post- andsporeHerbaceous plantsdominated undeveloped shellsare characteristic. the foraminifera represented bysmall basin withlowerof acoldarctic salinity, shallow icecovered sea.For theconditions formation occurred underconditionsof and overlaying thesandsofKazantsevo fragments ofpebbles, gravel, andboulders Formation oftheupperclay layer containing of SPIW. ice lenses, andfragments ofthelower part horizontal ofmossparticles, for preservation conditions. Suchconditionswere favorable the sandswere frozen inshallowmarine layer andhighicecontent indicate that sand solublesaltcontent inthesorted High were (MIS5)period present.the Kazantsevo of means thatthelandscapescharacteristic meadows existed alongthecoasts, which from thesandsindicated thattaigawithvast mouth. Resultsofthepalinological spectra beachzone neartheriver an underwater indicated thatsandswere deposited in granulometric-mineralogical analysis are bysandsofshallowsea. overlain The clays oftheSanchugovo formationMarine salts. ofmarine preservation thesearegression, after right whichallowed of foraminifera. Sedimentswere freezing The layer containsmollusksandsingleshells were bythepalynologic confirmed analyses. landscapes alongthecoastsofseabasin offorest-tundraconditions characteristic Pleistocene.in theMiddle Cold climatic basin(Sanchugovoa coldmarine formation) clay sediments formed intheconditionsof mouthisrepresented River by Khrestianka oftheprofile neartheThe lower part geological profile.the region, Quaternary mouthhaveRiver themostcomplete, for coastal exposures neartheKhrestianka development andpeataccumulation. The 226.08.2013 9:22:24 6 . 0 8 . 2 0 1 3

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7 70 GEOGRAPHY 0 δ ranging -26.8 between throughoutcoasts ishighlyvariable time, Sea composition oficewedges ontheKara units.of five geocryological The isotopic isgivenevolution. for It 15icewedges for reconstructionofthepalaeoclimate generations oficewedges were analyzed Stable isotope compositionsfor different accompanied byformation oflarge pingoes. ispossiblethatfreezing ofsedimentswas It sedimentsinashallowsea. alluvial-marine syngenetic freezing ofsaturated desalinated rather quickly asthere arerather quickly nosigns of to terrestrialmarine conditionsoccurred etal,[Streletskaya 2009].Changefrom relative to thepresent north position km more mouthwasextended River than300 large grain sandsindicates thatthe Yenisey al, 2002] shelf[Stein et under conditionsofdrying Formation ofalluvialsedimentsoccurred δ around –20.4 wedges showameanisotopic composition isotopic compositioninallofthem. The ice by meansofstableisotopes, despite heavy Dikson,Gydan) canbedifferentiatedKarga, The Holoceneicewedges (unitsSopochnaya δ around -17.0 layer, have heavier isotopic compositions δ D (Fig. 8a). etal.,D [Streletskaya 2011]. D. Recenticewedges, sampledinthe active 18 O andfrom –209.2 Fig. 8. 8. Fig. . δ 18 The compositionofpebblesand O- O O δ D diagrams for ice wedges in all geocryological units for different age sediments: age different for units geocryological all in wedges ice for D diagrams for for δ δ 18 18 O O O and–121.0 O and–154.2 to –117.8 and–16.2 Holocene (a); Late Pleistocene (b) O O O O for for for for composition andprevalence ofHCO bylightisotope ischaracterized terrace river A complexoflarge SPIWofthesecond top ofthe profile andpresence ofSPIW. of siltcontent from thebottom to the of the Yenisei agradual increase supported formation during ofthesecondriverterrace Severe climaticconditions sediments (TMGI). thawing found marine intheroof oficy Ca the Diksonarea are almostidenticalto the depositsin theicerich and clay fraction, theirratioofsand,Laptev silt, Seacoast.In inthe for formation oftheice-complex periods. Suchconditionswere reconstructed cold of coldwind-blownsnowpacksduring processes corresponding to thedevelopment Dikson isexplainedbywidespread nivation sedimentsnear Presence oficefine-grained (MIS2) upto 120mdepth(seemapinFig. 9). thelastcoldstage shelfduring the modern continental conditions, withlandoccupying Winter precipitation wasformed inthe the Diksonweather stationis–25.5°С). climaticmeanfor the present (theJanuary were –40±3°C. This is12–15°Clower than temperatures indicated thatmeanJanuary Temperature 1992] assessment[Vasilchuk, al., 2011]. et mouth[Streletskaya River the Krestianka near theDiksonsettlementandSPIW ofSPIWthelower levelis characteristic similar isotope andchemicalcomposition ++ inthechemicalcompositionofice. A 3 - and 226.08.2013 9:22:24 6 . 0 8 . 2 0 1 3

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7 reflects ahigherwinter temperature and The HoloceneSPIWisotopic composition Alaska. shores ofthe Yakutia coastallowlandsand “ice complexdeposits” of sections ofknown 9 – Lake Labaz 9 – (west theGydan Bay coast),4- 5 – (east theGydan Bay coas composition was (see studied Table the Sverdrup 2): Isla 1 – 16 – coastlinetrench, canyon or at channel;– present coastline; 11 day a) map of attime –shelf edge 11 000 14 –river paleovalley,5 –continental clay/mudst areas; 7–mud, 6–oceanic shelf; y; 17 submerged – coastline1 –highlands; 2–hills andlowlands; andla 3–alluvial during transgressive at phase; 9000 15 –coastline y; at 18 000 y; 1 (based on the Atlas of paleographic maps (2004) and R. Stein et al., 2002 with additions). Fig. 9. Relict ice wedges in the Late Pleistocene – Holocene, the Kara Sea Sea Kara the –Holocene, Pleistocene Late the in wedges ice 9. Relict Fig. age issimilarinitsvaluesto theisotopic SPIW oftheLate Pleistocene/Holocene isotopic compositionofthe Western Taymyr coasts to theinlandofpeninsula. The oxygen isotopes inSPIWdecreases from the ofthesea. an impact The numberofstable 18 sites The withSPWI ice wedges. whereisotopic –relict t), Karga, 8 – Lake Taymyr, 6 – 7–Sopochnaya Krestianka, determined b) inferred); 12 –ice sheets; 13 –submarine nd, 2 – the Dikson urban locality, 3 – , Sibiryakov 3 – locality, urban theDikson 2 – nd, custrine plans; lakes; 4–river valleys andtemporary one, shale; 8–silt, siltstone; sandstone; 9–sand, 10 226.08.2013 9:22:24 6 . 0 8 . 2 0 1 3

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7 72 GEOGRAPHY 2 fresh-water diatoms, ostracodes, and, later, diatoms,marine andtheir replacement of foraminifera, sponge spicules, shellsof bydisappearance of which isconfirmed sedimentation transitionedto theterrestrial, conditionsof second halfofMIS3,themarine andbythe sea levelwasquite short rise time(MIS3). beginning oftheKargino The the newtransgression occurred atthe ofsedimentation, theterrestrial type After break insedimentation atthe Yenisey North. that theZyrantime(MIS4)corresponds to a of MIS4were notfound, butitispossible MIS4 transition.Reliablydated sediments MIS5to sedimentsduring alluvial-marine SPIW. sedimentswere Marine replaced by sediments,marine formation of TMGI and one were accompaniedbyfreezing of deposition environment to theterrestrial Transitions from theprolonged marine freezing conditions. and Holocene, includingsedimentationand environmental changesinthe Pleistocene reliable reconstructionofpaleogeographic methods, whichallowedgeocryological a using comprehensive stratigraphic and of large bodies ofground icewere studied the Yenisey Gulfwithandwithoutinclusions The coastalexposures oftheGydan Bay and accumulation (ratherthantemperature). are to attributed changesinwinter snow and development ordegradation ofSPIW in theregion. frost Extensive cracking similar orslightlylower thanatthepresent formationduring oftheHoloceneSPIWare temperaturesPleistocene. January Mean heavier isotope content relative to theLate bya The HoloceneSPIWischaracterized ofHolocene. thecoldperiods during sediment icy freezing ofthepre-Holocene in theconditionsofcloseredeposition and compositions. The Holocenedepositsformed andmineralogicalhave similarparticle The HoloceneandLate Pleistocene deposits Seas.Laptev andEastSiberian composition ofSPIWonthecoasts CONCLUSIONS Continental border ofthe Western Sector 23.2 oftheShelfand Cryolithozone “The SC-1097.2012.5, Program ofRASProject ofLeading ScientificSchools RF Support wasfundedbytheProgramThis work of higher organic content. bya andcharacterized Holocene material profiles are pre- dominated byreworked sedimentswithhighicecontent. silty The the Holoceneoptimumandlater filledwith depressions formed during the thermokarst theHolocene, icewedgesIn were growing in ions areforchlorine typical theHoloceneice. isotope content andprevailing sodiumand of SPIWtheLate Pleistocene. Aheavier the hydrocarbonate ionsare characteristic (up to 6 analysis, andSPIW. Alighter isotope content from thestratigraphy, chemicalandisotope of theHolocene,periods whichisinferred in theLate Pleistocene (MIS2)andincold Formation ofSPIWoccurredstages: intwo the Late Pleistocene –Holoceneages. Dating ofthesedimentswithSPIWindicates composition ofSPIW. weathering (Dickson),andalightisotope cryogenic active –Chrestianka), (Makarevich andontheslopes(Sopochnaya Karga) ofthealluvialterrace in theupperpart from theincreasecontent ofthesiltfraction in theLate Pleistocene, which isinferred regression, occurred andclimate aridization Lower meanannualairtemperatures, sea complete disappearanceofpalynomorphs. arethe MIS2age, thespectra depleted until direction ofthesedimentscorresponding to landscapes. Up the profilein section oftheforest-tundracharacteristic andtundra age(MIS3)arethe sedimentsofKargino from derived thesamplesof pollen spectra oftheprofiles. the upperpart The spore- the profilesdecreasing withsalinity toward of are significantly salineinthelower part oftheloamy sedimentsofMIS3 majority limnitic microflora andostracodes. The ACKNOWLEDGEMENTS O ) anddominationofcalcium 226.08.2013 9:22:25 6 . 0 8 . 2 0 1 3

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7 Nazarov, D.V. ofthe deposits ofthecentralpart West . (2011)Quaternary Siberian 12. Meyer, L., H.,Schönicke, Wand, U., H.-W., Hubberten, Friedrichsen, H.(2000)Isotope stu- 11. I.D. in Deposits A.G.,Streletskaya, (2012) Quaternary Matyukhin, ofCryogenic The Salinity 10. F.A, Kaplyanskaya, Tarnogradsky, 9. V.D. (1986)RemnantsofthePleistocene ice sheetsin Gusev, Е.А.,Molodkov, ofsedimentsthefinalstageKazants- A.N.(2012)Structure 8. Gusev, E.A.,Arslanov, H.A.,Maksimov, F.E., Molodkov, A.N.,Kuznetsov, V.Yu., 7. Smirnov, S.B., Dansgaard, W. (1964)Stable isotopes inprecipitation. Tellus 16,pp. 436–468. 6. Pleistocene ofma- ravnin (The Danilov, subarkticheskikh I.D. (1978)Pleistotsen morskikh 5. Danilov, I.D. stroenie (1969)Merzlotno-facial’noe vodorazdel’nyh otlozhe- plejstocenovyh 4. Craig, waters. inmeteoric H.(1961)Isotopic variations Science 3. Bolshiyanov, D.Yu. (Passive iAntarktidy (2006)Passivnoe glaciationof oledenenieArktiki 2. M.N.Alekseev(Ed.), Atlasofpaleogeographic ShelfRegions maps(2004)In: ofEurasiafor 1. was partially fundedbytheGrantof was partially Phillips Russia.Datingofsediments Inc., Emanations ofHydrocarbons” andConoco Transformation ofFrozen Ground and State, Permafrost Dynamics, the History, of :Assessment oftheCurrent 3 REFERENCES Ph.D thesis. Geol. Sciences. Mineral. St.Petersburg State University. 26p. que. Isotopes in Environmental andHealthStudies 36,pp. 133–149. dies ofhydrogen andoxygen inground withtheequilibrationtechni- ice–experiences on Permafrost, Publisher,The Northern Russia,2,pp. Salekhard, 259–262. the Yenisei In: V.P. North. (Ed.), Proceeding Melnikov ofthe Tenth Conference International Geology 10,pp. 257–265. the permafrost for zone asanobject paleoglaciological research. Polar Geography and 2012. Vol. 443.Part 2.pp. 458–461. evo Transgression of (MIS5)intheNorth Western //Proccedings, Siberia Sciences, Earth Antarktiki sedimentsfrom thelower Neopleistocene-Holocene Yenisey area //Problemy i Arktiki Chernov, S.B., Zherebtsov, I.E.,Levchenko, S.B. (2011)Newgeochronological dataonthe subarcticplains) rine Press, University 1,Moscow of cryolithology), pp. 93–105(inRussian). inthelowerdividing ridges courseofthe Yenisey Problemy River). (Problems kriolitologii ofthePleistocene structure sedimentsof Eniseja(Cryofacial nij nizhnegotechenija reki the ArcticandAntarctic).AARI,St.Petersburg, 295p. (inRussian) the Mesozoic andCenozoic. Moscow, Nauchnyy Mir, 2,pp. 13–12(inRussian). , 2(88),pp. 36–44(inRussian). . Moscow University Press, University Moscow 198p. (inRussian). composition ofground ice. Germany, for oftheisotope determination Research, UnitPotsdam,Marine Potsdam, of theAlfred Wegener for Institute Polar and thank Dr. Isotope HannoMeyer Laboratory Russian GovernmentN.11.G34.31.0025. We

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7 74 GEOGRAPHY 4 Svendsen, J.I., Alexanderson,H.,Astakhov, V.I., Demidov, I.,Dowdeswell, J.A., Funder,23. S., I.D., Streletskaya, Vasiliev, О.L.,OblogovG.Е.(2012)Poligo- A.A.,Slagoda,E.A.,Opokina, 22. I., Streletskaya, Vasiliev, H.(2011) Isotopic A.,Meyer Composition ofSyngeneticIce Wed- 21. I.D., Streletskaya, Vasiliev, A.A.,Gusev, M.A., M.Z., Medvedeva, E.A.,Kanevskiy, Vanshtein, 20. 19. Streletskaya, I.D., Streletskaya, Gusev, E.A., Vasiliev, N.Yu., M.Z.,Anikina, A.A.,Kanevskiy, Derevyanko, L.G. 19. I.D., Streletskaya, Vasiliev, A.A.(2012) The IceComplex of Western Taymyr.18. In: V.P. Melnikov I.D., Streletskaya, Vasilev, A.A.(2009) Izotopnyj sostav poligonal’no-zhil’nyh l’dov17. zapad- F., Stein, R.,Niessen, Levitan, Dittmers, M.,Schoster, K., F., Simstich,J., Steinke, T.,16. Stepanets, Solomatin, V.I. (1982)Pogrebennye l’da15. reliktylednikovogo nasevere ZapadnojSibiri Romanenko, F.A., D.V., Mikhalev, Nikolaev, V.I. (2001)Podzemnye14. l’dy naostrovah ubere- Oblogov, I.D., G.E.,Streletskaya, Vasiliev, A.A.,Gusev, E.A.,Arslanov, H.A.(2012)Quaternary 13. Gataullin, H.-W.,Gataullin, M.,Hubberten, C.,Houmark-Nielsen, V., Ingólfsson, M.,Hjort, Henriksen, University,letin ofMoscow 3,pp.“Geography”), 57–63(inRussian). Sea)). Island(theKara University,Vestnik Mosk. Ser.on theSibiryakov “Geography” (Bul- nal’no-zhil’nye l’dy more) (Poligonal naostrove (Karskoe ground-ice Sibirjakova wedges Periglac. Process. 22,101–106.doi:10.1002/ppp.707. ges andPalaeoclimatic Reconstruction, Western Taymyr, RussianArctic. Permafrost and pp. 357–372(inRussian). ofdevelopment), Moscow, seas:CurrentArctic state Press, andhistory University Moscow system oftheLaptev Seaandtheadjacent (The Sovremennoe sostojanie razvitija iistorija L.A. Timokhov, I.E.Frolov (Eds.), morej Sistema iprilegajushhih morjaLaptevyh Arktiki: coastal dynamicsof Western Tayimyr). A.P. H.Kassens, In: Lisitsyn,J. Thiede, E.I.Polyakova, l’dy beregov Zapadnogo idinamika Tajmyra deposits, icecomplex,and (Quaternary B.G., G.A.,BolshiyanovD.Yu. Cherkashov, otlozhenija, podzemnye (2009)Chetvertichnye (Earth Cryosphere) (Earth Tajmyra sedimentstudiesof (Newresults ofQuaternary Western Taymyr). Zemli Kriosfera otlozhenij Zapadnogo issledovanijchetvertichnyh kompleksnyh rezul’taty (2007). Novye blisher, Salekhard,Russia,2,pp. 433–438. (Ed.), Proceeding ofthe Tenth Conference International onPermafrost, Pu- The Northern Cryosphere) Zemli (Earth nogo Tajmyra (Isotopic compositionofpolygonal wedge iceof Western Taymyr). Kriosfera 8369.2002.tb00086.x results.:preliminary Polar Research 21(2),315-322.doi:10.1111/j.1751– Sea, Kara glaciationinthesouthern O. andlate Quaternary river run-off (2002)Siberian Studies. Chronicles, Discussion)29, pp. 233–240(inRussian). of relictsofglacialicein thenorth (Buried West ofGlaciological MGI(Materials Siberia). Glaciological Studies. Chronicles, Discussion)91,pp. 129–137 gov Tajmyra to (Ground the iceontheislandsnext Taymyr of coastline).MGI(Materials Publisher,Northern Salekhard,Russia,2,pp. 293–296. (Ed.), Proceedingnikov ofthe Tenth Conference International onPermafrost, 2012, The Sea.In: conditionsofGydan Bay Coastdeposits andgeocryological V.P. oftheKara Mel- , 11 (3),pp. 14–28(inRussian). , 13(3),pp. 59–69(inRussian).

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7 2 . Vasilchuk, Y.K. sostav l’dov podzemnykh (1992)Izotopno-kislorodnyi –Opytpaleogeokri- 25. Trofimov, V.T., Badu, 24. Yu.B., Vasilchuk uslovijaGy- Yu.K. (1986)Inzhenerno-geologicheskie 5 scientific journals ongeographyscientific journals andgeocryology. Russian Geographical Society. Sheistheauthorofover 90scientificpublicationsinleading ofthe project. Member Scientific SchoolsofRussiaproject, theArctic Coastal Dynamics in the World program Ocean provided bytheRussianAcademy ofScience, theLeading (in Russian). to State Publishers, Paleogeocryological University Moscow Reconstructions). Moscow Isotope (Oxygen rekonstrultsii Composition ofGround Ice–Application ologicheskikh cow, MSUPress, 212p. (inRussian). Gydan Peninsula conditions).Mos- engineering-geological poluostrovadanskogo (The rev.2003.12.008 ScienceReviews23,1229-1271.doi:10.1016/j.quasci- Eurasia.Quaternary of northern M.J., Pielhagen, C.,Siegert, R.F.,Siegert, icesheethistory Stein R.(2004)Late Quaternary Matiouchkov, A.,Murray, A.,Möller, P., F., Niessen, O., Polyakh, L.,Saarnisto, Nikolskaya, M., Ó., J.P., M.,Kjær, Jakobsson, H.,Lunkka, Larsen,E.,Lokrantz, K.H., Lyså, A.,Mangerud, J., Evgeny A.Gusev IrinaD. Streletskaya papers. interpretation ofseismicdata.Author of about20scientific Research interests: Arctic geology, geological mapping, Petersburg ofGeomorphology). State (Department University Professor oftheFaculty ofGeography andGeoecology, St. of Head oftheDepartment “VNIIOkeangeologia”. Associate engineer-geologist” (1993).PhD inGeologyandMineralogy. G.V. namedafter Institute Plekhanov, specialization “mining oftheIPAa part Polar International Year part activities.Shetakes Courses University onPermafrostRussian International (IUCP)as and Gygan Peninsulas, Yenisei North. The leaderandorganizer of field researchexpeditions andconducted onthe Yamal, Taymyr inmanypalaeogeography ofArctic.Shehasparticipated sediments, Quaternary saline sediments, cryopegs, processes, relief formation, ecologyoftheArcticareas, frozen ground ice, periglacial mapping; permafrost geochemistry; permafrost Sciences.Mineralogical Herarea ofexpertise: State University.Moscow SheisPhD. inGeological and andGlacilology,Cryolithology Faculty ofGeography, Lomonosov graduated from St.Petersburg State Mining isAssociate Professor, of Department 226.08.2013 9:22:25 6 . 0 8 . 2 0 1 3

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76 GEOGRAPHY GlebE. Anatoly N.Molodkov Alexander A. Vasiliev graduated from State theMoscow changing. geocryology, geological mapping, palaeoreconstruction,climatic Earth’s RAS”. Cryosphere Research interests: Arctic geology, ofGeology.Master Post-graduate studentofthe of “Institute State University,Moscow specialization “geocryology” (2012). structure andevolution. Author ofabout100scientificpapers. Research interests: permafrost Coastal(Tyumen). andsubmarine SBRAS Institute Cryosphere (2005). HeadScientistoftheEarth University, Faculty ofGeology. DSc. ingeologyandmineralogy molluscan skeletal remainsmolluscan skeletal inLate Cenozoic chronostratigraphic”. Geochronology.for Quaternary D.Sc. inGeology: “ESR-analysis of EPR(ESR)Society, International HeadoftheResearch Laboratory onPalaeontologywork andStratigraphy. Full ofthe Member Aviation inKiiev, Faculty 1987–1989–graduate ofRadiotehnics; Oblogov graduated from theFaculty ofGeology, graduated from ofCivil theInstitute 60.039:22:25 9:22:25 26.08.2013