巉口早全新世泥炭层介形类种属组合及古环境响应

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1、毕业论文论文题目（中文）巉口早全新世泥炭层介形类种属组合及古环境响应论文题目（外文）PalaeoenvironmentresponsetoOstracodassemblagesintheearlyHolocenepeatlayersonchankouⅠ巉口早全新世泥炭层介形类种属组合及古环境响应摘要在研究黄土高原西缘定西地区的巉口剖面时发现，在该剖面下部泥炭层中发现有大量介形类壳体存在，通过其中的有机质14C测年得到剖面的年代模式图，发现下部泥炭层所处时代为早全新世，大约处于8000cal.aBP-11000cal.aBP之间。对该剖面下部含有介形类壳体的层

2、位进行了重点采样，并在实验室中对这些介形类壳体进行了鉴定，共发现4属7种包括2个相似种，分别为Eucyprisafghanistanensis，Eucypriscf.dulcifons，Heterocyprissalina，Heterocyprisincongruens，Tonnacypristonnensis，Ilyocypriscf.Bradyi，Ilyocyprissebeiensis。结合剖面特征、各类介形虫壳体数量以及介形虫各种属的生态指示信息，将剖面中的介形类壳体划分为四个组合，推测出定西地区早全新世气候变化情况（干冷-暖湿-暖干-暖湿），并由此

3、重建了定西地区早全新世的古环境，得知当时该地区出现过许多小型水体，甚至一度发展成浅水湖泊。关键词：介形类；泥炭层；早全新世；巉口；古环境ⅠPalaeoenvironmentresponsetoOstracodassemblagesintheearlyHolocenepeatlayersonchankouAbstractIntheresearchofchankousectioninDingxiarealocatedinthewesternedgeofLoessPlateau,wefoundmanyOstracodshellsinpeatlayersattheb

4、ottomoftheprofile.Throughtheorganiccarbonfor14Cdating,wegotanagemodelofthesectionandfoundtheformationageisabout8000cal.aBP-11000cal.aBPwhichistheearlyHolocene.FocusonsamplingtheformationatthebottomoftheprofilecontainingOstracodshellsandidentifiedthespeciesinlab,atotalofOstracodswit

5、h4generaand7speciesincluding2relatedspeciesarefound,theyareEucypriscf.Dulcifons,Eucyprisafghanistanensis,Heterocyprissalina,Heterocyprisincongruens,Tonnacypristonnensis,Ilyocypriscf.Bradyi,Ilyocyprissebeiensis.Combinedwiththefeatureofsection,numberofallkindsofOstracodshellanditseco

6、logicalindicatorinformation,theOstracodofchankousectionaredividedintofourcombinations,andestimatetheearlyHoloceneclimatechangesinDingxiarea(dryandcold-wetandwarm-dryandwarm-wetandwarm).ThusrebuildtheearlyHolocenepaleoenvironmentofDingxiareawhichtherehavebeenmanysmallwaterbodiesatth

7、attimeintheregion,evendevelopintoshallowlakes.Keywords:Ostracods;peatlayers;earlyHolocene;chankou;paleoenvironmentⅡ本科生毕业论文巉口早全新世泥炭层介形类种属组合及古环境响应目录中文摘要I英文摘要II第一章前言1第二章区域概况3第三章样品采集和处理43.1样品采集43.2样品处理5第四章样品鉴定与描述74.1Eucyprisafghanistanensis74.2Eucypriscf.dulcifons74.3Heterocyprissalina

8、84.4Heterocyprisincongruen