长江三峡中坝遗址地层的孢粉学初步研究

A PRELIMINARY STUDY OF SPORO POLLEN RECORD ON THE ZHONGBA SITE IN THE THREE GORGES,YANGTZE RIVER,CHINA

对重庆忠县中坝遗址剖面82个地层样品和遗址附近的12个现代表土样品进行孢粉分析,结果表明:表土样品中孢粉含量较高,沉积地层中频繁出现蕨类植物孢子(相对于木本和草本花粉,其数量多,比例高),揭示出中坝地区植被长期处于次生化状态。表土花粉中,松在乔灌木中占明显优势;旱生草本花粉以蒿属、十字花科和菊科等为主;蕨类孢子以水龙骨、三缝孢子、凤尾蕨、石松孢子和单缝孢子为主,植被处于次生化。地层花粉中,蕨类孢子以凤尾蕨属、卷柏属、其它三缝孢子和单缝孢子为主;乔灌木植物花粉以松属和榆属占优势;草本植物花粉中,禾本科、菊科、藜科和蒿属等含量较高。研究点孢粉分析显示,人类活动对中坝遗址影响较大:1)新石器晚期:先人栽培种植活动已经开始;2)新石器时代末期至六朝,受人类活动影响,植被覆盖度较低;3)商代至周初至秦汉时期,人类活动不断加强;4)唐宋时期,人类栽培种植活动较活跃;5)明清至现代,人类砍伐当地植被日趋严重,导致植被次生化现象增强。

The sporo-pollen analysis of 82 stratigraphical samples from the profile of T0102 at Zhongba Site,Chongqing City,Southwest China,and 12 surface samples show that the content of sporo-pollen in the surface samples is high and the fern spores（a large number and high proportion relativing to tree and herb pollen）appeared frequently,in dicating that the vegetation in the region has been in secondary succession for a long time.Pinusis dominant species in the surface pollen;Upland Herbs pollen are mainly consist of Artemisia,Cruciferae and Compositae.Most of fern spores are Polypodiaceae,Trilites,Pteris,Lycopodiumand Monolites.In the T0102 profile,most of fern spores are Pteris,Selaginella,Trilites and Monolites.The main components of the trees and shrubs are Pinus and Ulmus.In the herbs,Poaceae,Artemisiaand Compositae are dominant.The sporo-pollen analysis illustrated that human activities have great influence on the site of Zhongba：1）During the late Neolithic period,the cultivation and planting activities had begun;2）From the last Neolithic period to the Six Dynasty,the concentration of sporopollen in the layer was low because of human activities;3）From the Shang Dynasty to the beginning of the Zhou Dynasty to the Qin and Han Dynasty,the human activities were continuously strengthened;4）In the Tang and Song Dynasty,the cultivation of human became more frequent;5）From the Ming and Qing Dynasty to modern times,the vegetation of the site was deforested.Meanwhile,the secondary succession of vegetation was enhanced.