权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Studies on the Permafrost Occurrence Related to the Past Climatic Changes in Antarctic Regions

南极地区与过去气候变化相关的多年冻土发生的研究

基本信息

批准号：
01041004
负责人：
FUKUDA Masami
金额：
$ 6.72万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01041004/
关键词：
Permafrost Periglacial Phenomena Sea level change Post glacial period Active layer Climatic Change Antarctic IceーSheet Antarctic Peninsula

项目摘要

James Ross Island and Seymour Island locate in the middle of Weddel Sea near Larsen Ice Shelf. Due to the long periods of sea ice coverage, the mean annual temperature at both Islands is lower than western side of the Antarctic Peninsula and it stands -10^ﾟC.Ice free ground areas in both islands are exposed to the severe climatic conditions and permafrost develop in certain depths. To estimate the permafrost distribution, geo-eletric resistivity surveys were conducted at various locations.The vertical profiles of geo-electric resistivity of the ground indicate the existance of the discontinuity of resistivity. The depth of this discontinuity relates to the permafrost table. The horizontal profiles of geo-electric resistivity at the sorted circles show the internal structure of the frozen ground.At James Ross Island, marine terraces develop at three different altitudes ; upper terrace (+30-40 m a. s. l.), middle terrace (+15-20 m a. s. l.) and lower terrace (+5 m a. s. l.). The ages of middle and lower terraces were estimated by the results of ^<14>C dating measurements using shell samples as 25,000y. B. P. and 3,000y. B. P., respectively. The depth of the permafrost table at lower terrace is estimated as 6 m. It implies that the permafrost with 6 m depth formed for these 3000 years under the present climatic condition.Besides of permafrost occurrence at the surveyed areas, active periglacial phenomena were observed such as sorted stripes, sorted circles and stone pits. Transitional distributions of sorted circles and stone pits were mapped in detail on the slope. To monitor the active ice-wedge cracking under present climatic condition, the distance between the ice-wedge ice were measured with non-active cracking for two years periods.

詹姆斯罗斯岛和西摩岛位于威德尔海中部，靠近拉森冰架。由于长期的海冰覆盖，两岛的年平均气温低于南极半岛西侧，为-10^ C。两个岛屿的无冰地面地区都暴露在恶劣的气候条件下，在某些深度发展了永久冻土。为了估计冻土的分布，在不同地点进行了地电阻率测量。地面的地电阻率垂直剖面显示了电阻率的不连续性。这种不连续的深度与永久冻土层有关。圈层处地电阻率水平剖面反映了冻土的内部结构。在詹姆斯罗斯岛，海洋阶地在三个不同的高度发育；上阶地（+30-40米），中阶地（+15-20米）和下阶地（+5米）。中低层梯田的年龄是由^<14>C定年测量结果估计的，使用壳样品为25,000y。b.p.和3000年。B. P.分别。下层阶地的永久冻土层深度估计为6 m。这表明，在目前的气候条件下，这3000年形成了6 m深度的永久冻土。调查区除多年冻土外，还观测到分选条纹、分选圆圈和石坑等活跃的冰缘现象。详细绘制了分选圆和石坑在边坡上的过渡分布。为了监测当前气候条件下楔冰的主动开裂情况，对楔冰与非主动开裂冰之间的距离进行了为期两年的测量。