摘要
利用典型钻孔P5孔沉积物的岩性、测年、孢粉和有孔虫的分析结果，探讨了末次冰消期以来长江三角洲东南部古河谷区记录的气候波动和海平面阶段性上升过程及其控制下的古河谷沉积模式。研究发现本区古河谷末次冰消期（15～10ka BP）以淡水湖沼相沉积为主，4m厚的泥炭可能是新仙女木事件的反映。10～9ka BP发育滨海相粉细砂、粉砂沉积，反映此时海平面较为稳定。9～8ka BP发育溺谷相泥质粉砂、粉砂质泥沉积，厚达11m，反映海平面快速上升作用下的高速率充填。至全新世大暖期，古河谷区沉积顶界已和长江三角洲平原的第一硬土层埋深大致相同，反映古河谷已基本被填平。
A typical borehole P5 was examined for lithology, dating, spore-pollen and microfossil to reveal the phases of climate and sea level fluctuation and the associated sedimentary facies recorded in the paleo-incised valley sediments in the southeastern Changjiang Delta Plain since the last deglaciation. The results show that freshwater marsh facies prevailed in the paleo-incised valley during 15 - 10 ka BP. A peat layer, 4 m thick, evidenced the cooling event of Younger Dryers. Coastal silty sand and silt dominated the strata of paleo-incised valley, reflecting the relatively stable sea level during 10 - 9 ka BP. Muddy silt and silty mud was 11 m thick during 9 - 8 ka BP, reflecting the quick deposition in the drowned valley due to the rapid rise of sea level. The deposition surface of the valley approximated to the buried depth of stiff muds in the delta plain at the beginning of the Holocene optimum, indicating the termination of filling in the paleo-incised valley.
出处
《古地理学报》
CAS
CSCD
2007年第2期217-226,共10页
Journal of Palaeogeography：Chinese Edition
基金
上海市自然科学基金(03ZR14025)资助
作者简介
赵宝成，男，1981年生，硕士研究生，现从事第四纪环境演变研究。E-mail：zbch.com@tom.com。
