摘要
来自1 4C、δ1 3C、粒度和地球化学元素的分析表明,南京江北地区在5 12 0 a BP、6 2 4 0 a BP、4 84 0 a BP和8914 a BP是气候相对暖湿期,而85 2 3a BP和6 5 2 0 a BP可能对应的是相对干冷的气候。该区在94 90～4 84 0 a BP期间沉积速率具有明显不均一性,94 90～8730 a BP期间沉积速率为5 6 m m / 10 0 a,86 95～85 6 6 a BP期间为6 2 m m /10 0 a,而85 2 3～4 84 0 a BP期间沉积速率仅为8m m / 10 0 a,上述现象可能与94 90～85 6 6 a BP期间该区经历过海侵和地壳沉降加快有关。由于在第5～7层中未发现海相有孔虫,可以肯定该区海拔高于7m的地带在94 90～4 84 0 a BP期间未受海侵影响。
Analyses of 14 C dating, δ 13 C, granularity and geochemical elements reveal that the north bank of the Yangtze River of the Nanjing area should be in warm-humid climate periods at 5120 a BP, 6240 a BP and 8914 a BP, but maybe relative cold-dry climate periods at 8523 a BP and 6520 a BP. The sedimentation rate of the area has an obvious inhomogeneity during 9490~4840 a BP, i.e., during 9490~8738 a BP, the rate of sedimentation is 56 mm/100 a, 8695~8566 a BP 62 mm/100 a, but 8523~4840 a BP only 8 mm/100 a. The above phenomenon maybe relates to marine transgression and crustal subsidence acceleration during 9490~8566 a BP in this area. Since there is no foraminifera in the fifth to seventh layer of the Linfengqiao profile, it is certain that no marine transgression occurred in this area of altitude 7 m higher above sea level during 9490~4840 a BP.
出处
《地质论评》
CAS
CSCD
北大核心
2005年第3期347-352,共6页
Geological Review
基金
国家自然科学基金项目 (编号 40 2 7110 3 )
南京大学"985"自然地理学科建设基金
南京大学现代分析中心测试基金项目资助成果
关键词
南京市
BP
粒度
地球化学元素
沉积速率
沉积物
环境演变
地层记录
north bank of the Yangtze River
Nanjing area
9490~4840 a BP
environmental evolution
stratigraphic record
