Fluctuation of Antarctic Ice Sheet and historical development of landforms during Quaternary

1.在Lutzow-Holm湾地区，根据AMS ^ C测年，到晚更新世，可能是最后一个冰间冰期，东南极冰盖已经从索亚海岸最北部的无冰岩石中退缩<14>，那里发生了海侵。虽然这一时期的绝对高海平面是未知的，但相对海平面至少比现在的海平面高出10米。从化石贝壳的δ ^ O（PDB）值可以看出，末次冰间冰期东南极冰盖的融化非常活跃<18>。末次冰期期间，海平面下降，但东南极冰盖并没有重新前进，至少没有前进到索亚海岸最北端的无冰岩石上。可能在末次冰期之后，融水过程变得活跃，然后部分侵蚀了前者，抬高了海滩，形成河流沉积。全新世中期，东南极冰盖沿着索亚海岸从现今无冰岩石中退缩，全新世海侵发生在3000 ~ 7200 yBP（~ 1000）<14>。在不考虑均衡反弹的情况下，高海平面至少达到了20 m asl。海侵可能被小的海退打断。海平面相对稳定期出现两次，分别在现今海平面以上20 m和11 m左右。从化石贝壳的δ ^ O（PDB）值来看，全新世海侵期间东南极冰盖的融化不如最后一个冰间期活跃<18>.在阿蒙森湾地区周围，<14>来自里瑟-拉森山地区湖泊沉积物岩芯的AMS ^ C数据表明，自10，000 yBP以来，该地区的相对海平面一直低于23米。

1. Around the Lutzow-Holm Bay region The East Antarctic Ice Sheet had retreated from the ice-free rocks in the northernmost part of Soya Coast by the late Pleistocene, probably the last interstadial, on the basis of the AMS ^<14>C dating, and marine transgression had occurred there. Although the absolute high sea level during that period is unknown, the relative sea level reached at least 10 m above the present sea level. Melting of the East Antarctic Ice Sheet during the last interstadial had been conspicuously active judging from the delta^<18>O (PDB) values of fossil shells.During the LGM, sea level had fallen ; however, the East Antarctic Ice Sheet did not re-advance, at least on to the ice-free rocks on the northernmost part of the Soya Coast.Probably after the LGM, meltwater process became active, then partially eroded the former raised beach and formed fluvial deposits. The East Antarctic Ice Sheet retreated from the present ice-free rocks along the Soya Coast by the middle of the Holocene.Holocene marine transgression occurred from 3,000 yBP to 7,200 yBP in ^<14>C age. High sea level had reached at least 20 m asl without taking isostatic rebound into consideration. The transgression was probably interrupted by minor regressions. Relatively stable sea-level period occurred twice, around 20 m and 11 m above the present sea level. Melting of the East Antarctic Ice Sheet during the Holocene transgression was less active than during the last interstadial, judging from the delta^<18>O (PDB) values of fossil shells.2. Around the Amundsen Bay regionAMS ^<14>C date, from the lake sediment core in the Mt.Riiser-Larsen region, indicates that relative sea-level at the region has been lower than 23 m since 10,000 yBP.