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1.
Plant remains have been found on ground recently deglaciated from the Omnsbreen glacier. They consist of Salix herbacea, Salix spp., Silene acaulis, Polytrichum norvegicum, Kiaeria of. starkei, and some unidentified species. Their age has been determined by the radiocarbon method to approx. 550 years, indicating that the present Omnsbreen glacier emerged as late as the clima deterioration in the late Middle Ages. The past vegetation was similar to the present, but slightly more thermophilous, indicating a rapid clima deterioration in the fourteenth century. 相似文献
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A total of 26 polar bears have been killed in Svalbard since January 1987. Fifteen of these cases were self defense, four precautionary measures, six acts of mercy and one unknown. Twelve of the 15 self defense cases occurred in the wilderness; none occurred in populated areas. Most self defence cases involved nonresidents of Svalbard and hence people not familiar with polar bear behaviour and encounters. 相似文献
3.
许家窑组及许家窑文化层年代问题的磁性地层学证据 总被引：5，自引：2，他引：5
许家窑文化遗址的发现将传统上被认为是早更新世前后的泥河湾层的年代范围推至晚更新世 ,由此建立的许家窑组被确认为我国北方晚更新世湖相沉积的标准地层。近几年对包含许家窑文化层在内的泥河湾层用高分辨率磁性地层学方法研究结果表明 ,在文化层以下 3m处发现了厚度达 6 m以上且分布连续的反向极性带 (未见底 ) ,综合分析认为 ,该反向极性带为松山反向极性带。这一发现否定了在文化层以下 4— 5 m处存在布莱克反向极性偏移的报道。根据松山反向极性时的结束时间为距今 78万年及泥河湾层的沉积速率推算 ,许家窑泥河湾层的年代范围应为早更新世晚期至中更新世 ,而许家窑文化层应为中更新世早期。由此可见 ,泥河湾层的年代范围及分组方案尚需用多种手段进一步研究才能定论 相似文献
4.
对山西襄汾敬村更新统剖面黄土—古土壤的系统古地磁学研究表明,磁化率曲线与洛川黄土—古土壤磁化率标准曲线有较好的对应关系。这种对应关系由极性测量结果进一步证实。根据这一对应关系可推断,敬村剖面底部微红土及其下的砂砾层年代应老于1000ka。这一研究结果也可与距其1km外具有类似接触关系、年代有争议的丁村遗址进行磁性地层学对比。 相似文献
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发现于1957年的匼河文化遗址的年代一直存在较大的争议。近四十年来,考古学和地学工作者虽然从化石、地层等多方面研究,但仍未得出令人信服的可靠结论。受许家窑遗址及小长梁遗址的最新磁性地层学研究结果的启示,过去两年对山西南部匼河遗址从磁性地层学的角度进行了深入、系统的研究,研究发现匼河遗址剖面的磁化率曲线呈顶部高,中间2.5m到13m处较宽阔的低值带,具有华北黄土高原黄土L9的特征,底部又呈高值的分布趋势,这种磁化率的分布关系与洛川标准剖面的S7-S12有较好的对应关系,从而得出文化层以上地层剖面的年代范围为0.7-1.02Ma,由此可推算位于底部磁化率高值带以下的文化层的年代至少早于1.02Ma,完全不同于匼河文化遗址0.247Ma的现行认识,而与苏朴、朱日祥等人对许家窑、小长梁遗址,马圈沟遗址年代的最新认识趋向一致。 相似文献
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对许家窑泥河湾组两个平行剖面的高分辨率古地磁研究结果发现,在剖面的中下 部存在厚度约 １０ｍ（未见底）的巨厚负向极性带．根据正负极性带的相对位置及组合关系并 结合剖面附近相关层位火山豆的Ｋ－Ａｒ绝对年龄值进行分析认为,该负向极性带应为松山反 向极性时带．此结果否认了作者关于在遗址剖面底部存在Ｂｌａｋｅ反向极性偏移的结论．由此 推断,分布在许家窑一带的泥河湾组年代应为早更新世晚期至中更新世早中期． 相似文献
8.
桂林水南洞洞穴沉积物的古地磁记录及其古环境意义 总被引：1，自引：0，他引：1
通过对桂林水南洞2.5m厚的洞穴沉积物剖面的古地磁初步研究,其结果及地质证据表明该沉积剖面形成期可能与贾拉米洛正向期对应。根据磁化率、磁性矿物的特征和沉积学特征,对该地区这一地质时期的古环境变化提出以下认识:1.第三暖湿期,以钙华沉积为特征;2.第二干冷期,以含有少量钙质的黄褐色粘土为特征,并以含有高矫顽磁性矿物和低磁化率为特征;3.第二暖湿期,以互层的红褐色粘土、含高含量钙质的粘土或钙华为特征,并以含有低矫顽磁性矿物和高磁化率为特征;4.第一干冷期,以褐灰色粘土为特征,并以含有高矫顽磁性矿物和低磁化率为特征;5.第一暖湿期,以地下河沉积相(砂卵石为主)为特征。 相似文献
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OTTO SALVIGSEN REIDAR NYDAL 《Boreas: An International Journal of Quaternary Research》1981,10(4):433-446
Th/U dating and radiocarbon dating of 'old' shells are discussed, and amino acid ratios from shells are used as a method of relative-age dating. The Svalbard area has been completely covered by an extensive ice sheet at leats once. New data from Sjuøyane indicate that such glaciation took place in the Early Weichselian. The Middle Weichselian was a period of interstadial conditions. Series of beaches of assumed Middle Weichselian age occur in several places in western Spitsbergen while no such beaches are known in the eastern part of the archipelago. The maximum glaciation in the Late Weichselian is assumed to have taken place about 18,000 B.P. In the western part of Spitsbergen, the Late Weichselian glaciation was limited and local, while the eastern part of the archipelago was covered by an ice sheet. Kongsøya has a pattern of Holocene shoreline displacement which indicates that the centre of this ice sheet was east of kong karts Land. 相似文献
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EILIV LARSEN STEINAR GULLIKSEN STEIN-ERIK LAURITZEN ROLF LIE REIDAR LØVLIE JAN MANGERUD 《Boreas: An International Journal of Quaternary Research》1987,16(3):267-292
Skjonghclleren is a marine-cut cave with 15–20. m thick pre-Holocene sediments. Corings and excavations reveal three beds of extremely fine-grained, laminated sediments alternating with blocky sediments. The laminated beds are interpreted as glaciolacustrine sediments deposited subglacially at times when ice sheets covered the area, suggesting at least three glaciations after the cave was formed. The blocky/diamictic sediments were formed by frost-shattered blocks from the roof of the cave during ice-free periods, and mixing with the fines through slow mass movements along the floor of the cave. In the diamictic sediment beneath the uppermost laminated bed, almost 7,000 bone and teeth fragments of birds, mammals and fish were found. Birds dominated, with little auk and brunnich's guillemot as the most frequently occurring species. Arctic fox was the dominating mammal. During climatic optimum of the interstadial, conditions seem to have been similar to present-day coastal Finnmark, with North Atlantic warm water entering the Norwegian Sea. Two radiocarbon dates on bones and three Uranium series dates on speleothems from this bed all cluster around 30,000 B.P., i.e., the end of the Ålesund interstadial. Above the uppermost laminated bed, bone fragments of birds, fish and mammals, deposited between c . 12,000 and c . 10,000 B.P., were found. Little auk dominate. The occurrence of squirrel is worth noting since it is limited mainly to areas with coniferous forest today. The beds below the 30,000B.P. bed are poorly dated or undated, but it is tentatively concluded that the entire sediment sequence was deposited during the Weichselian stage. It seems that the cave was formed at a high relative sea-level stand sometime during the Early Weichsclian. Two recorded palaeomagnetic excursions seem to correlate with the Laschamp/Olby and the Lake Mungo events, respectively. 相似文献