南极普里兹湾晚第四纪以来硅藻组合及气候变化的研究

STUDIES ON LATE QUATERNARY DIATOM ASSEMBLAGE AND PALEOCLIMATE OF THE PRYDZ BAY,ANTARCTICA

对南极普里兹湾ＮＰ９３－２和ＮＰ９５－１两柱样沉积硅藻进行了定量分析。两柱样分别可划分出３个和７个硅藻组合带。前者的优势种是Ｎｉｔｚｓｃｈｉａｃｕｒｔａ和Ｔｈａｌａｓｉｏｓｉｒａａｎｔａｒｃｔｉｃａ，次优势种是Ｎ．ｋｅｒｇｕｅｌｅｎｓｉｓ和Ｎ．ｒｉｔｓｃｈｅｒｉ；后者常见的优势种有Ｎ．ｋｅｒｇｕｅｌｅｎｓｉｓ，Ｎ．ｃｕｒｔａ，Ｄｅｎｔｉｃｕｌｏｐｓｉｓｓｐｐ．和Ｔ．ｌｅｎｔｉｇｉｎｏｓａ，常见的次优势种有Ｅｕｃａｍｐｉａｂａｂｌａｕｓｔｉｕｍ，Ｔ．ａｎｔａｒｃｔｉｃａ和Ｔ．ｇｒａｃｉｌｉｓ。利用Ｎ．ｃｕｒｔａ／Ｎ．ｋｅｒｇｕｅｌｅｎｓｉｓ比值并结合１４Ｃ测年数据，可将１５０００年以来南极气候的变化划分出８个古气候带，其中完好地记录了Ｈｅｉｎｒｉｃｈ１事件、波令－阿德罗暖期、新仙女木冰期、全新世低温期等重大的气候变化事件，而南极的全新世低温期是首次报道。

Diatom floras in the cores NP93 2 and NP95 1 from the Prydz Bay,Antarctica have been analyzed.Results show that Nitzschia curta and Talassiosira lentiginosa are the dominant species and N.kerguelensis and N.ritscheri are second dominant species in the core NP93 2,and N.kerguelensis,N.curta,Denticulopsis spp. and T.lentiginosa are frequent dominant species and Eucampia balaustium,T.antarctica and T.gracilis are common second dominant species in the core NP95 1,three and seven diatom assemblage zones can be divided respectively in above two cores. According to the N.curta/N.kerguelensis ratio and the 14 C dating,the author divided paleoclimate since 15 000 a B.C. into eight paleoclimatic zones:Ⅰ.Warm period of last glacier,Ⅱ.Heinrich Event 1,Ⅲ.Bolling Allerod,Ⅳ.Younger Dryas,Ⅴ.Warm period,Ⅵ.Suitable period,Ⅶ.Short period of low temperature,Ⅷ.Warm period.It's the first time to find the short period of low temperature of Holocene in Antarctica.