13kaBP以来滇池地区古环境演化  

Paleoenvironmental Evolution in Dianchi Lake Area since 13kaBP

作　　者：吴艳宏[1] 吴瑞金 薛滨[1] 钱君龙[1] 肖家仪[2] 

机构地区：[1]中国科学院地理与湖泊研究所湖泊沉积与环境开放实验室,南京210008 [2]南京师范大学地理科学学院,南京210097

出　　处：《湖泊科学》1998年第2期5-9,共5页Journal of Lake Sciences

基　　金：国家自然科学基金!49672132;中国科学院湖沼专项联合资助

摘　　要：根据DC93一1孔孢粉组合、总有机碳（TOC）、总氮（TN）、碳氮比（C／N）、有机碳同位素δ13Corg、磁化率（χ）、频率磁化率（χfd）等资料，结合14C、210Pb和137Cs测年，滇池地区13ka以来的古环境演化历史经历了以下几个阶段：13—10．2kaBP．气候偏凉湿，湖水深度不大；10．2－7．5kaBP，气候向暖湿过渡．湖水渐深；7．5－4．0kaBP，气候暖湿，出热条件达到最佳配制，湖水也最深．6．5kaBP前后，气温最高，这一时段古气候状况存在次级波动；4．0－2．7kaBP，气候突转干旱．湖水最浅；2．7－1．7kaBP，气候温湿，湖面扩大，湖水变深；1．7kaBP，人类活动影响的加剧，使湖泊环境的变化更为复杂．Dianchi Lake (25°04'N. 102°41'E), lying to the south of Kunming City. the capital ofYunnan Province. is an ideal field for studying the evolution of the Southwest Monsoon.The core D93 - 1 is sampled in the lake at the depth of 4.05m. The 14C ages at 0.65m.1. 7m. 2. 65m and 3. 95m are 1670±140aBP, 4540± 220aBP, 6700±160aBP and 2900±1100aBP respectively. The sedlment rate of upper layer determined by 210 Pb and 137 Csmeasurement was about 1. 78mm/a after 1948A. D., and 1mm/a for the last 250 years.Meanwhile. such environmental proxies as pollen assemblage. total organic carbon (TOC ).total nitrogen (TN ) , (C/N ). 13 Corg, magnetic susceptibility (χ ) and frequency dependent magnetic susceptibility (χ fd ), have been used to restore the history of environmental evolution in the lake area since 13kaBP.As a result. Dianchi Lake has undergone the following climatic variations since 13kaHP:13m- 10kaBP. it was cool and wet: 10 - 7. 5kaBP. it was a transitional period while climate transited to warm and wet and lake water level became higher. 7. 5- 4kaBP. it was warm and wet with little variation. The highest temperature ernerged about 6. 5kaBP. 4-2. 7kaBP, the cllmate changed to cool and dry. suggesting an abrupt change in environmental proxies. 2. 7- 1. 7kaBP, all environmental proxies exhibited the characteristics of slight warm and wet climate, and , lake area enlarged with lake water level uprising. Since 1. 7kaBP human activity has made a notable impact on the environmental evolution.

关 键 词：滇池地区 古环境 环境演化 古气候 

分 类 号：P531[天文地球—古生物学与地层学] P532[天文地球—地质学]