A Study on Peat Deposition Chronology of Holocene of Zorge Plateau in the Northeast Qinghai-Tibetan Plateau
A Study on Peat Deposition Chronology of Holocene of Zorge Plateau in the Northeast Qinghai-Tibetan Plateau
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发表时间：
2001
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通讯作者：
Sun Guang
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作者：
Sun Guang
青藏高原是一个独特而特殊的环境变化区域，著名的若尔盖高原湿地位于青藏高原东北部，面积4605.28km2，湿地中泥炭广泛堆积在宽阔的河谷中，蕴藏着丰富的环境变化信息，对研究全球环境变化具有重要价值。建立一个正确的全新世时间基准是充分利用大量环境信息的前提。现有的全新世时间基准是基于14 C数据建立的，存在局限性和不足，因此有必要寻找一种更可靠的方法来校正14 C年龄结果。作者在若尔盖高原湿地泥炭层中发现了泥炭纹层结构，结合14 C测定全新世年龄的新方法，其分辨率有可能达到年的标准。本文以红原泥炭遗址Ⅱ号矿的年代为基础，建立了一个完整的、可信度高、分辨率高的全新世泥炭沉积年代表，并系统地公布了除红原地区外的若尔盖高原几个重要泥炭地的年代，提出了若尔盖高原泥炭沉积的年代序列。这些结果表明，若尔盖高原晚泥质沉积形成于12 000 yr BP以上，泥炭沉积开始于11 500 yr BP，并在11 500~12 111 yr BP出现了一次强烈降温的仙女木事件，全新世大暖期形成于9 500 ~ 2 000 yr BP。在全新世9500 yr BP之前和2000 yr BP之后，泥炭沉积速度减慢，泥炭沉积最慢的时期出现在现代。在环境差异的影响下，高原泥炭沉积年龄差异较大，总体上，高山区晚于宽谷区，中全新世以宽谷区为主。
Qinghai Tibet Plateau is a unique and special region on environmental change,the famous wetland of Zorge Plateau is in northeast Qinghai Tibetan Plateau and covers 4 605.28 square kilometers.In the wetland,peat was widely piled in the wide valleys and abundant information about environmental change was contained in it,which is very valuable for investigating the globally environmental change. Erecting a correct time reference frame of Holocene is the precondition to make use of great environmental information.Existed time reference frame of Holocene was established based on the 14 C data,and it is limited and has Shortcomings.So,it is necessary to look for a method that is more reliable and can emend result of 14 C age.Authors discovered peat varve structure in peat layers of Zorge Plateau wetland,which could be used as a new method combinig 14 C for determining Holocene age.And it is posible that the resolution come up to standard of year. The paper,which is based on age dates that were made just from mine Ⅱ of Hongyuan Peat Site,found an age table of Holocene peat deposition.The table is a more complete system and has higher believable and higher resolution.In addition,the age dates of some important peatland in Zorge Plateau except the region of Hongyaun were published systematically,and then the age sequence of peat in Zorge Plateau was presented in the paper. These results indicated that the Latest mire mud of the Zorge Plateau formed in above 12 000 yrBP and the deposition of peat started in 11 500 yrBP.It was alse closed of a violently falling temperature, Younge Dryas ,appeared in 11 500～12 111yrBP.The Holocene megathermal was formed from 9 500 yrBP to 2 000 yrBP,which is a period of faster peat deposition.Before 9 500 yrBP and after 2 000 yrBP of Holocene,peat deposition slowed.The slowest period of peat deposition has appeared in modern times.Under the effect of difference of environment,peat age of deposition has big difference in the plateau.Generally,the high mountainous regions are later than the wide valley,and the latter was dominant in middle Holocene.