摘要
江陵剖面沉积物记录了近9000a来的气候变化和人类活动历史。根据多环境指标综合分析,重建江陵地区近9000a来的气候环境演化。研究表明,8900~6300aB.P.为暖湿气候期;6300~4700aB.P.为冷期;47003400aB.P.气候偏暖偏湿;3400~2500aB.P.是湖沼泥炭堆积期,气候暖湿;2500aB.P.以来,该地区沉积环境发生了显著变化,由湖泊及湖沼堆积转为洪水漫滩堆积,古云梦泽开始萎缩,气候变干变冷。早期人类活动始于6200aB.P.,以种植经济作物罂粟及牧草类植物唇形科和车前草等草本花粉的出现及增加为标志;4700aB.P.开始,人类在定居点附近从事农业、牧业兼少量经济木本的种植;人类大规模活动始于3400aB.P.,禾本科含量急剧上升与湖周农田耕作范围的扩大有关,阔叶树和杂草花粉的增多与定居点扩大及其周围普遍种植经济阔叶林有关。随着定居点扩大和人类活动的加剧,地表土壤侵蚀严重,入湖陆源粗颗粒物质和有机物质增多;湖泊沉积物表现为粗颗粒含量迅速增加,各粒径波动频繁,TOC、TN和C/N出现高值,δ^13C出现低值。
The information about the climate change and early human activities for 9 000 a in Jiangling area, Hubei Province, China, was documented in lake sediments. According to comprehensive analysis on multi-proxy of the sediment from the Jiangling section, this article reconstructed climate and environment change in Jiangling area during the past 9 000 a. The results show that the climate was warm and wet in 8 900~6 300 aB. P. ,cold during 6 300~4 700 aB. P. ,warm and wet during 4 700 ~3 400 aB. P. ,warm and wet in 3 400~2 500 aB. P. ,of which llmnlc peat was developed wiely, cold and dry since 2 500 aB. P.. The preliminary human activities started from about 6 200 aB. P. ,marked by cultivation on economic crop Papaverraceae and the increased occurrence of pasture plant,such as Labiatae and Plantago. The human activities increased from about 4 700 aB. P.. The human activities mainly were agriculture planting and grazing near settlement, yet with small piece of economic trees. The large-scale human activities started from 3 400 aB. P. , the Gramineae content ascended fleetly, suggesting the extension of farmland around the lake shore. The increases of broad-leaved trees and weed herbs indicate the expansion of settlement around which broad-leaved trees are replanted. With the extension of settlement and the enhancement of human activities, there existed the enhanced erosion of surface soil and the increase of coarse particle matters and nutritive material into lake. The lacustrine sediments were characterized by the prompt increase of coarse materials, and frequent fluctuation of different forms of grain size,and high value of TOC,TN,C/N, and low value of organic matter δ^1C.
出处
《地理与地理信息科学》
CSCD
北大核心
2008年第1期85-90,共6页
Geography and Geo-Information Science
基金
国家自然科学基金项目(40472151)
国家重大基础研究项目(2003CB41520)
关键词
江陵地区
气候变化
人类活动
全新世
湖泊沉积
Jiangling areas climate change
human activities
Holocene
lake sediment