Builet主nofGlacierResearcb7（1989きj69－j符 j69 ⑥DataCenterforGlacierRescarch，JapaneseSocietyofSnowandIce

Preliminary research onlacustrine deposits andlake cvolution on the southern slope of the West Kunlen Mountains uShijie，ZHENG Benxing．andJIAOKeqin La王1Zholユ‡nsモituteofGはciologyaridGeocryoiogy，Åcademia Sinica，Larほあou，Chin急

くRece毒vedDecember5，1988；RevisedmanuscriptreceivedFebruary3，ユ989）

Abstract

BasedonfieldinvestigationsanddataobtainedfrommorethanlOOsamplesintheiaboratory，the characteristicsofiaclユStrinedepo雨sandtbedistribution，geneSisalldevolutionoflakesontbesoutb slopeoftheWestKunlunMountainshavebeendiscussedfromthcviewpointofsedimentarystratト graphyandstratigraphicchronology． Lakesontbesout‡iSideofthel好es毛足uniunMou鵬aillSaredisもributedi17depressionbasiれSalong awideeasトWeStteCtOnicvalley．Watercomesfrommeltediceandsnow．Thegenesisofthelakesis tectoれic，bl止Tianshuiha呈Lakeisatbermothawlake． ByanalysisoflacustrinesedimentarystratigraphyandC14chronology，TianshuihaiPalaeo－Lake mighthaveexistedsincetheearlyQuaternary．GuozhaLake，AksayqinLakeandTianshuihaiLake as we11as North TianshuihaiLake were connected together then．The deposit modelis an up 泄aCCumulatiompaもte汎Uptothe呈ate‡）ie主s紬Cene，theunifiedpaleo州Iakehadbeenseparatedand disappearedgraduaユIy．Thelakeieveihasgrownanddeclinedrepeatedlysincethelast如c主ation・A periodwi払bighiakelevelex主stedabout36000yr，B．P．TbereisalaclユSもri－－edepositedlayer，dark 叫grayCiay，inthedril】edcorepro創e．Then，the】akeleveideclined・Apurplesandandgrave‖ayer wasdeposited、Thelakelevelroseagainabout21000yr．且P．AclaylayerofdarkMgraylakeイacies appearedagain，InthewesternpartofNorthTianshtlihaiLake，about4800ma・S・l・，thereisalake terraceabout40mhigherthantoday’siakelevei．OnthesoutheastsideofGuozhaLakeatabotlt5800 ma．s圭tbereisalsoaiaketerrace3mabovetbeexi＄t主nglakelevei．DuringtbeHoloce一喝Iakes shrarlkbystages，preSenting父Veralcircularlakeもerracesorlakeshoreもraces・

1．lntrodu亡tion from1965鰍1970）；and35mmatHetia‡10nthenorth Siope（1326ma．s．王．；datafromユ954－…ユ97乳Themean IntheslユmmerOf1987，theat血ors，aSmembersof ann11alとempe柁tureis beloⅥF －5ひC o‡l払e p王aとea11 theSino仙JapaneseJointExpeditiontoWestKunlun， Surface，and about M13．90C near the snowiine．The investigated the modernlakes and paleolacustrirle existing glaciers on this ma＄Sif are well－developed deposits on也e soutbern slope oft壬Iel貯est Kunlun andco‡lCentrated．Thereare408gまaciersontbenorもh Mountains． Siope，COVeringanareaof1954．63km2，and244gla－ Tbel野est Kuniun Mouぬains areiocated at the Ciers，1347．即km2inareaonthesout圭ISlope．Mostoぎ northwest margin of the Qinghai一Ⅹizang Plateau， them are valley glaciers；SOme bigice caps have borderingthe Xinjiangfrom Tibet．Most peaks are developedthere，tOO． above6OOOma．si；thehighest，CalledKtmltlnPeak，is Duetoasevereenvironme吼rtlggedte汀ainand 7167ma．sエ（85055’E，35¢19’N）．Theciimateiscoldand ab既nCeOflocalpopulation，detailedfieidinve或iga－ dry．The汀Ieanalュnuaiprec毒pitationiso‡1iy犯6mmat tionsandresearcllbavenotbeencarriedoutbefore．A Tia王1Sbuihaion the soutb slope（4900m a．s烏data feww詰terneXplorerscamebereaモ払ebeginnユ椚gOf Jニ7） Bulletin of Glacier Research

tはs ce11tl汀y，and reported tile eXiste王1Ce Of glaciers in払edrainagebasi‡10fNortilTiansiluibaiLake；10 andlakes．Inthesummerof1985，theSinoJapanese glacierswithareaofl．80km2andicevolumeofO．0326 JointGlacialExpeditionto West Kunlun Mountains km3inthedrainageofTianshuihaiLake；129glaciers COnductedabriefinvestigationinthisarea，andpub～ withareaof709．08km2andicevolumeof136．2698km3 lished some papers onglacioIogy，permafrost and intheAksayqinLakedrainagebasin；62glacier’SWith paleogeograpby， area of544，34kTn2andtheicevoiumeof92．2799km3 TIlispaperdealswiththeiacu痩rinedepositsarld inthedrainagebasinofGt10ZhaLake；and90glaciers lakeevolutiononthesouthslopeoftheWestKunlun withareaof170．34km2andicevolumeof15．5528km3 Mountains，and further discusses the relationship in the Bangda Lake drainage basin．In the warm betweenlakeevolutionandclimatic－glacialchanges SeaSOn，a VaSt amOunt Of meltwater flowsinto the fromtheviewpointofsedimentarystratigraphy and lakes，andthelakelevelrises．Forexample，thewater Ci汀OnOiogy． levelofGuozha Lake rose O，14 m fromJuly19をo August28，1987，Observedby CaoZhentang、Thisis equalto3416×104m30fwaterflowinginto thelake． 2．E）istrjbution，geneSIS，andcharacteristicsofmod・ Exceptforevaporationonthelakesurface，thewater ern takes volume wouldbemore thanthat． AsthelⅣest Kunlun Mo11ntains arelocated on a Lakes on tbe soutlュslope of tbeう材est Kunlun p壬裏eatlirまtbeinterior of a contine王1t，the climateis Mountainsoccurmainlyinthetectonicbasinwithin Very dry．Strong solar radiation causes strong eva－ thewidevalleyformedbyfaultsintheW－Edirection poration．Thesefactorsstrongly affect the chemical （Fig．1）．From west to east，thelakes are：North propertiesoflakewater．Chemicalanalysis（Tablel） Showsthatseverallargelakeshavebeenbecomesalt lakes，Thetypeoflakewaterchemistryisasfollows： Cl‾¶Na＋typefor BallgdaLakeandAksayqinLake with mineralization degrecs oflOO393．96mg／1and 54259．65mg／1respectively；anObviousdifferenceex－ istsbetweenthesouthandthenorthpartsofGuozha Lake；ClnトMNa十typeinthenorthpartwithmineraliza－ tiondegreeofl1658－011Ⅵg／1，aTldCl，HCO¶wuNa＋and Mg2＋typeinthesouthpartwithmineral室zationdegree Of3840．96mg／1． There are severaltypes oflake genesis on the SOuthslopeoftheWestKunlunMountains．Thelarge lakes such as North Tiansh11ihaiLake，Aksayqin

ノ・－一－一票ま細もまれ℡ 払 G18¢ier〟Cご・ぬYeご X 恥＄8 Lake，GlユOZわaIノake，andBangdaLakeareoftecとOnic Origin．But，TianshtlihaiLake，a Smailiake，is a ▲ 托息k 6訂しkk仁 一－－・・〟 Hlgh叫y thawinglake．Atthepresenttime，thegroundicelayer Fig・1・LocationoflakesonthesouthslopeoftheWestKunlun exposesinthelowerpartofthecliffbankofthelake． Mou）1tains Morethanlmthicknessofgroundicewasfoundata depthof13minadriilholeatthebankoftheiake，王t TiarlSbuihaiLakeくseparatedinto five smalllalくeS isconcludedt壬Iatthereexistspermafrostbeneaththe now）withtotalareaof4km2，TianshuihaiLake，area bottomofthelakethatisonly3．5mdeep，Inadditio‡ち Ofaboutlkm2and3．5minmaximumdepth；Aksayqin there are many smallglacially erodedlakes and Lake，160km2inareaand12．6minmaximumdepth： moraineNMdammedlakesneartheperipheryofexisting GuozhaLake，244km2inareaand81．9minmaximum glaciers． deptb；andBangdaLake，106km2inareaand21．6m irlmaXimlユmdepth．Thewaterintheselakescomes mainlyfrommeltediceandsnow．Accordingtodata OftheGlacialInventoryofChina，thereare12glaciers Withareaof3，69km2andtheicevolumeofO．1104km3 Li房㍉扇． j7Z

Tablel．Mainchemicalcomposition oflake water of the southslope of the West KunlullMou11tains．

C皿瞼痛感c8鳥on如e書き T洩dc珊短nt 恥8i V扇混 鹿0 融pe 疲訂ぬ侶猥ま 壬血Ⅶ感■ 戚 職級d紆Ⅸ鹿a！騨 Ca2＋ Mがヰ K｛ Na＋ 臨tion（me川 Zation（11唱／l）PH

2 0．8372 （妻．封47 0．1892 （事．1391 113，53 7、鮒 HCO喜一一式a2＋，噸十

2 ¢．4235 0．1083 0．0056 0，0348 軋56 7．49 HCOぎ」：乱2＋，噸＋

Nor払ea叙p揖lof 860．8萬弔お．5782 朗3＿3（‡07 軋7き80 58．62湘 33．2481 醐臥6諮6 54259，65 臥53 CトーNa＋ 払醸痛感A血山海瀾Ak鑓粥ぬbなe 喜 阿 b ヤd∝針‡勒 CIw9卦 Totd G蓮開山ke934．0183 1．4¢3 1．ま916 ¢．07428．53纏 0，1379 1．518 Mei餌場短rof31瀾彪 Gl血yaG】acier 0，5631 0，5286 0，馴48 0，0】97 ひ．572 H N鵬画Of 脇間加点壷 84尋，2慧3 0．ヰユ32 ま9．8927 79i．60 32．3ヰ74 慾4．7罪？8＿詣S草 娼．0盛2 3ユ，9693 狩3．9王3¢ 欝531．98 8．48 CトーNa＋ No血画d Guozha Lake 183．82421．3550 26．6333 133．582512．2534 181，1444 0．2659 22．6944 8．1841150．0 11658．01 9．18 CI㌧」巾十 Mi劇e画d Gは淀ぬbke 59．7＄93 3，¢752 14．iO75 37．9≦板 4．鵬 6臥宣終始 草．ま詣i lO，1159 2．粥44 46．95＄5 3糾㊥．粥 8．92 0‾灘鞠」隠憫許

S仇戒k；威鱒戎of G服baL或e 53，Si82 2、紙き8 12．7238 33．24？2 4．9朗4 53，8逢53 8＿3250 9，3Z樹 2．4552 4ま，ア391 3457．5跨 8．94 0【，HCO豆脚Naふ，野ヰ

Ba喝血bke 1728．4149 27《6287 1682，15 18．6362 1732，0795（）．0197 242．29 54▲9872 1434．7926 100393、96 臥30 Cト【Na＋

3．StratigraphyoflacustrinedepositsoffiveJakeson paleorlake shore traces can be seen clearly，Which the south s10Pe Ofthe West Kunlun Mountains reflectiakeleveifluetuations．A section of terraces WaS made at t‡le WeStern bank of thelake（Fig．2）． ユJ．1’りJ抽 7、ん川∫／…／ん〟Jんノん－ Åccordi王1gtOt壬1eClヰdating，theageoftlleSediments Fivesma11lakes，1inkedbystreamtoeachother， Ontheterraceat4835m a．s．1．is17480±155yr．B．P． are scattered，withlakelevelat4800m a．s．LIts TheC14datingwasconductedinIsotopicChronologト SOurCeis connected with TianshuihaiLake by a CalLaboratoryofGeographyDepartmentofLarlZわou Stream，a11d洩elowererldisjoi11edtoKliShuiLakein Universlty；王nOSとoftilem uSedtheorganicmaとeriai， theXiaoerkeVa11ey．Aroundthelakebasin，thereare and a few did the calcareous materialinsediments． SeVeralaccumulation terraces and paieo、・・＜1ake cliffs． Theageofdepositsatthedepthofl．5mbeneaththe Towardtbecenterく）fthelaket）aSin，mariy Circular basilュbottomatabolユt4802ma．s．l．is17360士180yr， 〔 Altitude Highv∂y 澗．己．5．1．

8 ， 0 ち 中 （ ー 一 ． （ノU q b 2 O ▲ q ， G － 〔 ．U ∪ 旬 へ ∪ 1 〔 J 8 U

（ 0

ロ叩th Proヂile clちD塾tinq Proヂile 、l－、（‥．．〉 S 9 （m） SlO Yr．8．p．Depth （m） －ー：’－ ∴＿J・一・・・・・・、

0、、う Eヨ S摘 りh80！7～S て．0 一三祭70ニー一口 巨∃ siまt

1．う －73る0ミ180 17700ヱ175 臣事 Sま1tyこ1ay

田 clay

Iギ ・こ、・ Fig．2．Profileofdepositsandterracesor壬払ewesとernsideof North Tia魚ShuihaiLake J詔 Blユ11etin ofGlacier Researc‡l

B．P．，and15110±300yr．B．P．attheupperlayer．This∋epth cor食Sl－ clら 〇るtln9 Showsthatthelakelevelof17000yr．agowasatleast （m） 購m緑励ert王IantOd野，andtbatthesete汀aCeS are 摘8う0ニ297ミ）Yr．≡．P． regressive－erOS主onaiones，Thechangesofscdimentav ryfaciesalsoshowthat，duringperiodsofhigh1ake level，Sandswithgravelsweredepositedinthelake・ Sidearea，Sandsintheshallowlakebottom，andsilty －Clayintbe deeper part．Tbe terracesⅥrereformed laterinthestablestagesduringthelakeshrinking．

JJ．ユ 上け川んリブJrん川ゴ／…〃汀J／ム血・ ModernTiallShuihaiIノakeissmallwithlakelevel at4836ma．s．l．，Suppl主edbysomespringsatthefootof もegen丘 the mountainin the southwest direction．However， 払ere was a壬Iugeまake before，Calied Tia王1Shu呈hai PaleoNLake．Basedontheoutcropsoflacustrinede－ 匡∃G∫a＞el posits，thispaleo1akewasjoinedtogetherwithNorth 巨∃clヨy TianshuihaiLake，KushuiLakein the Xiaoerke Valieyto the northwest，and Aksayqin Laketo the east，andevenconnectedwithGuozha‡．ake．Aclear ‡2．0 巨ヨ慧慧Of trace of paieo－1akeshorelinereached about4880m 13．〇 転ヨlこeし叩 a．s．l．，bⅥt，at preSent，a VaStlacustrine accumulated lL．ロ plain洩reもcbesinthearea．Byarlalysisofthecbarac－ 二こ：：iミ こ1ay ｝ithJ亡監 teristicsofQuaternarygeologyandgeomorghologyin 1S．0 thelakebasinandhistoryoflakesonthewholeNorth TibetPiatea11，Webelievetbatt‡1eTianshlユibaiPaleo Fig－3．ProfileofcoreSIl，mOdernT主an洩uiba壬Lake・ 欄Lakehadexistedsincet‡lebeginningoftheQuater－ nary，andby Late Pleistoceneit wasseparated and りepthlCore S12 clらD∂tまng もegend disappearedgradually．ThewholecoreofSIldrilled 1る21Cエ195Yr．a．P． atTianshuihai，15mi11depth（Fig．3），COnSistsof重acus・ － 〔 － － 一 ち 1さ7：0ニ†55 Yr．8，P． trineclaywitbgraycoior．Tbecまay80cmdeept）elow i ノ

2 0 匡ヨ加朝雄戒 thegroundsurねcehasaC14datingageof46850±2970

一 一 0 yr．B．P．，Whicbcouidrepresenttbeyoungestdeposits ノ 巨ヨsilty⊂ユ3y

． Oftbe TiansbuibaiPale8－Lake．Tbe core profile of ． 縞 一 ハ SI2，drilledattbelowbankofthemodernlake，9．5m V Cユ8y

亡 0 in depth（Fig．4），reVeals the outline oflakelevel ノ

Sem℡nted S∂nd Changessince40000yr．B．P．Thedepositsbetweenthe ′ ∩ む レ ∂nく5 Gravel

deptbs of9．5m and8．3m are gravels with sandy

S声すヽd layers．Thesizeofgravelsisgenerally2N5mm，and 36750tり20 Yr．8．P－ 2T3cminmaximumindiameter．Thesegravelsare Eヨ Sand artd G∫2Vel rounded to a certain extent and arrangedin order， h′ith c18V Whicbsbowsthecharacteristicsof仇vialdepositsat thelakesideduringper主odsoflowlakeievel．Åsand layerlyingbetween8．3mand7．6mindepth，having Fig．4．ProfiieofcoreSI2，mOdernTianshuihaiLake－ Shallowlakefacies，Showsthatthelakelevelbe宮an rlSlng．Then，ぬecoreof7．6mto7mchangedtotile pl汀piishredsandandgravelagaill，Showingtbelake depositsofdeeplakeねcies，grayClaylayer．Itsageof Sbrinkingandthelakeleveldropping．Froml，5mto C14datingis36750±1320yr．B．P‥Thesethreelayers O．2m，itisgraylacustrineclay，and contains some representthecyc王eoft‡lelakeievelcba‡喝eSfromlov わ盗iまplantre王Ⅵains．TbislayerrepreserltSaperiodof to壬1igb．The（箋eposits from7m tol．5m cha三唱e tO highlakelevelandexpandinglake：Ti－eC14datinglS Li（7fαJ． J73

18728±155yr．B，P．intheioverpartoftbis壬ayer，and Cieartracesofpaieolakesboreline・But，aWidelacus－ 16210±195yr．B．P．intheupperpartofit．Inaddition，trineplainstretchesontheeastside，becauseofsand someC14datingsofdarkgraylacustrine clay were andmuddepositionbythestreamcomlngfromthe obtained near Tianshuihai：they are 20000±170yr． eastinto thelake・At the north bank，the authors B．P．，18420±245yr．B，P．，16530士145yr．B．P．，andsofoundthesandandclaylayers（Fig．5）．Amongthem， o王ュ．TIleSeStrOnglysuggestthataperiodofh短hlake tbeageofblackdaylayersis34735±820C14yr．RP． levelexistedduring21080yr．B．P．，tO15000yr．B．P・ andofblacksandiayeris22522±670yr－B．P．Tbis alsoshowsthatthelakelevelwashighabout35000yr． ユユ．・1八一叫叫んJJ．√血・ B・P．，identicalwiththeresultobtainedfromthearea Thelake…1evelof Aksayqin Lakelies at4844m Of TianshuihaiLake．Moreover，in the section of a．s，i，Theauthorswentnearthecenterofthelakeby terracelinthenortheastsideofthelake（Fig．6），the rubberboattomeasurethedepthandtakesamples C14ageof許ayClayatl・25mdeepis18520±385yr． 育omtllebottom，andねundablackciaylayerof9cm B・P・，and16235±120yr．B．P．at the top．This also thick and a yellowsandlayer atthebottom ofthe Showsthataperiodofhighlakelevelexistedabout lake．Onthewestside，thereareseveralterraceswith 15000yearsago．

Aユtitude 爪 3．5．1．

ぎig．5．SectionofAksayqinLakea王1dits－10rthbarlk・

Depth Plリr】】e clむDatinQ 3，4．G蝕光鬼α上道触 （爪） S】る くYrふP・） Guozha Lake，withalakelevelof5080ma．s．1．， 、‥ ニ ケご・・・‥ ‥・‥－・、・： occupiesalsoatectorlicbasinsurroundedbybedrock 9．§ ∴・．‡・－・・、 slope．Thelakeisverydeepwithasteepstlbaquatic SIope（Fig．7）．Takingsamplesfromthelakebottom， し0 転ヨsilt 1Bう20！30う the authorsfoundthatthebottommaterialat81．9m 田Clろy 1．5 deeplSyellowsilty－Clay．Wetookbottomsediments 鞠818CkClるy 2．0 30cmthickat17．4mdepth，Tbeupperpartisyellow き弓 Pldnt R亡巾8ins L叫er siitywciay，andtbeloⅥrerpartgrayClay．Tbe water 2．う 国⊂1さy ｝1th Pl∂nlR帥8ins temperatureatthebottomisTC． Duringthestageofhigh1akelevel，Waterdrained away toward the west along the va11ey，andjoined Fig．6・Profileoflacustrinedepositsofterracelonthenortheast sideoftheAksayqinLake． TianshuihaiPaleo－Lake．0nlyonthesoutheastsideof thelake，therearethreeterraces（Fig，7）．Terracelis abolユと1m壬1igber abovetilemOdernlakelevel，T‡－e materialoftheupper・partisagravellayer，Ofabol止 20cmthick，andthelowerpartis a redsandy clay layer． プ摺 Bl】lietin ofGlacier Research

Fig－7．SectioIlOfGuozhaLakearlditsterraces・

Terrace2is about3m higher above theiake JJ∴；＿β〟J仰山J．（イA、（、 levei．Boththeupper2mandthelowerpartaresand Themodernlakelevelof王箋angdaLakeis4902m andgravellayers．BetveenthesetⅥFOlayers，thereis a・S・l・TheterracesareveryweiLdevelopedaroundthe aiayerofredclayofabotlモ20cmtbick，redaboveand iake（ぎig．乳EverlOnぬe t〉edrock aroⅥnd thelalくe gray ciay beiow；its C－4ageis21500±200yr．B．P． basin・SeVeraite汀aCeSandcliffsareciear王y，Cutat Terrace3isaboutlOmhigherabovetilelakeievei，It almost280mhigherthant！lemOdernlakeievel．Itis iscomposedofsandandgTaVel，formedfrommixed di班cult亡O Say Whet‡1er tbe bigh paleo岬Iakeievei Slopedepositsarld all嗣7ialdeposits asiakesidesedi－ Sli穐redfromneotecモonicmovementornot．However， ments． periodsofhighiakeievelmighthaveexisted．Obser－

SE Terrace Zone B∂ngda Lake

Fig．臥SectionofBanきざdaLakeanditsterraces． LigfαJ． J∴・了 vations suggest that Bangda Lake，Puer・Lake，and qinLake and even Guozha Lakein the east，Were DulidlilJake on the east side were once connected about3000km2in totalarea．And the totalarea of together．1野ithinthelake basin，tbere are4deposト moderrllakesisabout410km2，Onlyl／7－1／8asbigas tioれalterraceswithaltittldesof4905m，4921m，4948 thePaleo－Lake．Co†l況qtlelltly，WeCallthisageoflake m arld4965m a．s．1．respectively．Especialiy，Orlthe expansionthe”greatlakeperiod”．Duri11gtilatperiod， broad stlrface of terrace2，there are severalpaleo althot唱h alternate warm－COld changes of ciimate iakeshorelinesin ridgeshape formedinthe stable OCCurred，itwasgenerallydamp． stagesofthelake shrinking process．Terracelwas （2）UptoLatePleistocene：Thealtitudeofmountains formedatthebaseofTerrace2．C14agesofthelight Of the marginalpart of the Plateau（such as the grayclaylayerinthesectiondugonTerracel（Fig．9） Himalayas，theGangdisandtheKarakoram）reached were15900士120yr．B．P．and15880±115yr．BP．Itneartheirpresentheight，WhichcouldobstruCtWarm mightbededucedthatthelakelevelthenreached、at －dampairmassesfromtheIndianOceanTheclimate least，theheightofTerrace3whentheseclaylayers gradually becarne drier and drier．In addition，with weredeposited，about40mbigherthantoday’s．1、his upliftofthePlateau，theheadwarderosionoftheriver isidellticalwith the res111t from North Tianshuihai made part of the water of TianshuihaiPaleo－Lake LこIkし、． 蔦0Ⅵ7inとO the Karakax River170r血ward a王0王1g tbe GunsbiRiver．Asaresljlt，uptOabotlt470腑yr．B．P，， nepth Prorま1e on clちDating もeg引1d the great TianshuihaiPaleo－Lake was disappea：red （rn） Terr8Cel Yr．凸．P． and separatedtoseveralsmal11akes．TheⅥaStlake 皿Ⅲbed∫。Ck basinbecameastretch／OflactlStrine＿plain（C14ageof 団Sand∂ndClay thelacustrineclayatthetopofSIIcoredrilledonthe lう880±、、5 plainis46850±2970yr．B．P．）．Thisisagreatchange E；ヨsand and a turningpointirltheevolution oflakes on the 闇00亡－20 匡ヨc18， SOuthslopeoftheWestKunlunMountains．Afterthe decayoftheunified paleo血1ake，eaChseparatedlake S8nd and Cfa＞el 1．0 presentedaperiodofhighlakelevelagainabotlt35000 yr．B．P．Tbis主sindicatedbyぬefoliowingCiヰdates： 36750±1320yr．8．P．：the王acl】Strineclaylayerin the 】．3§ SI2coredrilled at Tianshuihai；34735±820yr．B．P∴ Fig．9．Profi－eonTerraceslo柑a喝daLake▼ thelacustrineclaylntheprofileonthenorthsideof AksayqinLake；30935士1700yr．B．P．：atraCtOfgray lacustrineclaycover－edbymoraine，Ontheeastsideof 4．Evolution oflakesonthesouthslopeoftheWest Chongce Glacier，nOrtheast of Guozha Lake．This Kunlun Mountains periodofthehighlakclevelcorrespondstotheinterq glacialsubstage of thelast glaciation．The climatc Evolution ofthelakes onthe south slope ofthe WaSClearlywarmduringthatperiod，bothontheplain WestKunlunMountainsisc】oselyrelatedbothtothe in eastern China and the mountains in the western tecとOnicupiifもく）ftheQinghai一ⅩizangPlateauandtbe part。metOthewarmclimate，giaciersonthelⅣest globaic】imaticchanges．Thechangesofiakeson血e Ktiniun Mot量ntains meited aIld retreated qlユickiy．Å PlateatlCanbedividedinseveralperiods． 1argeamoljntOfme】twater幻owedintolakes，reSuitir唱 （1）Early and Middle P】eistocene：According to the thelake expansion andlake－levelrise．Later，the result of Zheng Mianping’s research（Zheng et al．， lakesshrank． 1983），withintheTibet，thegreatestareaoflakeswas Uptoabout21000yr．B．P．，withclimatebecoming l／50rmOreOfthetotalareaofTibetormoreatthat COlder，theglaciersbeganadvancing．C14datingofthe time，tentimes aslarge asthe totalarea ofmodern moraineonthesouthsideoftheChongceIceCapgave lakes．Therefore，theycalledthisperiodan”extensive the age of21046士716yr．BP．，and that of the end lakesandriversperiod”．Lakesonthesouths】opeof moraineinfrontofGuozhaGlacier20106±385yr．B．P， the West Kunlun Mountains also grew，Great Tian－ Thiscoldperiod，inwhichmean annualtemperature sbuibaiPaleo－－Lake，COnneCtedtoKushuiLaketothe WaS about6【10ロClower than today，and glaciers westandNorthTia‡1S主1uihaiLakei！てtbenorth，Aksay～ developedonalargescaleorl血eearth，iscailedtbe J硲 Bu11etinofGlacier Research lasttheglaciationmaximlユm．But，itissurprisi重唱that arestllt，ablユgeamOunt Ofwaterflowi喝i‡1tOlakes tbiscoldperiodwasaperiodofhighlakelevelontbe made払elake－1evelrise．Later，iakes dlrank once south slope oftheWest Kunlun Mountains．AllCIA mOre． agesofthegrayclayonthelacustrineaccumulation （3）SincethebeginningofHolocene：Astheintergla－ terracearebetween21000yr．B．P．arld15000yr．B，P，Ciationcametheiakesshrankby stages，finai王y be－ Thelakelevels of North TianshuihaiLake and COming many saltlakes．A series of eircular paleo Bangda Lakewere，then，atleast40mhigherthan Jakeshorelinewasleft aroundeachlakebasin． today’s． Inshort，thethreemainstagesoftheevolutionof 王nttleareaOfCbaivobaoLakeinXilづiangPro－ lakes on the sotltb of thel貯est Klユnlun Mountains Vince，Wangeial．（1986）researchedtherelationship were：1）the”GreatLakePeriod”；2）the”LakeJevel betweentheadvanceandretreat ofglaciers andthe FluctuationPeriod”；3）the”LakeShrinkingPeriod”， lakelevelchanges．Tbeyalsofoundt壬Iattileperiodof COrreSp（）ndingtoEarlyandMiddlePieistocene，Late t壬Ielastglaciationmaximumwasaisoaperiodofhigh pleistoceneand王ioiocerle，reSpeC扇veiy． lakelevei．Inourview，pOSSiblereasonsforthehigh lakelevelduringthe cold stage are：1）the area of References glaciersincrea＄edenormousiyinthattime，a‡1dtbis l野ang，J．ggガg，く1986き：Lakeleve三貴uctua如ns呈n Cba言woモ〉aO catlSed a feedback efねct to the solar radiation Ba＄in，aSanindicatorofthechangesofpaieoclimate軸 balance；2）withincreasingglacialarea，therun…Off PreSS） ofmeltwatergrewinlargequantities；3）atthesame Zheng，M，ggαJ．（1983）：On salinelakesin Til）et，Cllh乱Acta time，theamountofevaporationdecreasedgreatly．As GeologicalSinica，2，184…193（inCbinese）．