东南极冰盖上新世大规模退缩事件  

Major collapse event of the East Antarctic Ice Sheet in Pliocene

作　　者：刘小汉[1] 韦利杰[2] 黄费新[3] 方爱民[3] 琚宜太[3] 李潇丽 周学君[1] 

机构地区：[1]中国科学院青藏高原研究所,北京100085 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国冶金地质总局矿产资源研究所,北京100025 [4]北京自然博物馆,北京100050

出　　处：《地质科学》2013年第2期419-434,共16页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家"十二五"专项(编号:CHINARE2013-02-02);国家自然科学基金项目(编号:41272216;41206183)资助

摘　　要：笔者近年对东南极内陆格罗夫山(Grove Mountains)开展了上新世以来冰盖表面波动的综合研究,运用冰川地质、地貌、土壤、沉积岩、孢粉组合及宇宙核素等各种方法手段,提出东南极大冰盖形成以后并非稳定演化至今,而在上新世早期时发生过大规模退缩,其前缘至少曾经退缩到格罗夫山地区,距现今冰盖边缘约400 km。之后,冰盖又迅速膨胀,到距今2.3 Ma时,冰面至少超过现今高度约400 m。以后冰面缓慢平稳下降,至1.6 Ma时,东南极冰盖进入第四纪振荡期,但重新上升的冰面再也没有超过现今高度的100 m以上。东南极冰盖大规模消融事件在全球尺度上也有所响应,例如北半球大冰盖形成,青藏高原整体剧烈隆升,塔里木盆地黄土出现等。这类行星尺度的气候变化可能与直布罗陀海峡关闭与地中海盐化事件,巴拿马地峡关闭等大地构造事件有关。The multi-disciplinary study of past ice surface elevations in the Grove Mountains of interior East Antarctica provide direct land based data on the behaviour of the East Antarctic Ice Sheet since the Pliocene. The glacial geology,the ages of cold desert soils, the depositional environment of younger moraine sedimentary boulders and their spore pollen assemblages combine to imply a possible significant shrinkage of the ice sheet before the Middle Pliocene Epoch,with the ice sheet margin retreating south of the Grove Mountains（ -400 km south from its present coastal position）. Exposure age measurements of bedrock indicate that the elevation of the ice surface in the Grove Mountains region subsequently rose at about Mid-Pliocene to at least 400 m higher than today＇s levels. The ice surface then progressively lowered, with some minor fluctuations. Middle to Late Pleistocene exposure ages found on the lowest samples, at the ice/bedrock contact line,indicate a long period with ice surface elevations was kept at current level or complex fluctuation history during the Quaternary Epoch. Such event of Antarctic ice sheet collapse should correspond with some of huge tectonic events in north hemisphere in global scale,such as the Messinian salinity crisis in the Mediterranean region.

关 键 词：东南极冰盖 格罗夫山 上新世 宇宙成因核素 暴露年龄 动态演化构造事件 

分 类 号：P542[天文地球—构造地质学]