地理科学进展 ›› 2014, Vol. 33 ›› Issue (6): 786-798.doi: 10.11820/dlkxjz.2014.06.007

• 第四纪研究 • 上一篇    下一篇

中国内陆区湖泊沉积所反映的全新世干湿变化

郭超, 马玉贞, 胡彩莉, 伍永秋, 鲁瑞洁   

  1. 北京师范大学环境演变与自然灾害教育部重点实验室/地表过程与资源生态国家重点实验室, 北京 100875
  • 收稿日期:2013-12-01 修回日期:2014-04-01 出版日期:2014-06-25 发布日期:2014-06-25
  • 通讯作者: 马玉贞(1957- ),河南太康人,教授,博导,主要从事环境变化研究,E-mail:mayzh@bnu.edu.cn。 E-mail:mayzh@bnu.edu.cn
  • 作者简介:郭超(1988- ),陕西西安人,硕士生,主要研究方向为环境演变,E-mail:gc@mail.bnu.edu.cn。
  • 基金资助:
    国家自然科学基金项目(41271207);科技部国家重点基础发展计划(973)项目(2013CB956001);高等学校博士学科点专项科研基金项目(20120003110019)。

Holocene humidity changes in inland China inferred from lake sediments

GUO Chao, MAYuzhen, HU Caili, WU Yongqiu, LU Ruijie   

  1. Key Laboratory of Environmental Change and Natural Disasters, MOE/State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
  • Received:2013-12-01 Revised:2014-04-01 Online:2014-06-25 Published:2014-06-25

摘要: 湖泊沉积记录的环境演变是全球变化的重要研究领域之一,通过对中国内陆区中30 个湖泊研究成果的总结和梳理,探讨了全新世以来该地区干湿变化的规律和区域分异。通过降水量结合传统分区方法将中国内陆区分为西北干旱区、东亚季风边缘区和青藏高原区。对每个湖泊样点以500 年为时间间隔,以孢粉为主要干湿指标,综合氧同位素、有机质及碳酸盐等,将湖泊干湿状况划分3 个干湿等级(干旱,半湿润,湿润),建立区域干湿指数。结果表明,中国内陆不同区域全新世可能经历了不同的干湿变化过程:①西北干旱区基本上是早中全新世干旱,中晚全新世相对湿润,但区域差异明显;②东亚季风边缘区早全新世早期干旱,早全新世晚期和中全新世相对湿润,晚全新世干旱;③青藏高原区的湿润时期主要发生在早中全新世,但是不同地区有所不同。对比分析显示:西北干旱区的干湿变化可能受西风环流控制,但在时间和强度上区域内部差异较明显;东亚季风边缘区可能主要受东亚季风控制;青藏高原地区早中全新世的湿润可能与印度季风的增强相关。

关键词: 湖泊沉积, 气候变化, 全新世, 中国内陆区

Abstract: Environmental changes recorded by lake sediments have been one of the major tools for reconstructing the palaeoenvironment and palaeoclimate in many parts of the world. Spatial and temporal patterns of humidity changes during Holocene have been reconstructed based on the compilation of recently published paleoclimate records from the inland areas of China. The climate of this region is sensitive to large-scale climate forcing. We divided China's inland areas into the arid northwestern region, the East Asian monsoon-margin region and the Qinghai-Tibet Plateau according to the amount of precipitation and natural zones. Sediment records from 30 lakes with reliable chronologies and robust proxies were selected to reconstruct dry-wet conditions based on a three-class ordinal wetness index (dry, sub-humid, humid) with assigned scores from dry to wet periods at individual sites for 500-year time slices. Then we formulated the regional dry-wet index, which may represent the average change of the regional dry-wet conditions. The proxies used in these records include pollen assemblages, oxygen isotope ratio (δ18O), organic matter and carbonate content (mainly pollen assemblages) data. The results of our synthesis show that the moisture conditions have experienced diverse changes over the Holocene in different regions of china's inland areas. Arid climate prevailed during the early Holocene, and relatively wet climate characterized the middle and late Holocene in arid northwestern China. But the climate change differed from place to place—the further into the west, the drier the climate during the early and middle Holocene and wetter in the late Holocene. In the East Asian monsoon-margin region, drier climate also prevailed during the early Holocene, and a wetter period may had occurred in the mid-Holocene, then the climate underwent another transition—it was driest in the late Holocene. In the Qinghai-Tibet Plateau, the wettest period may had occurred in the early and mid-Holocene, then the climate became dry gradually, but there was a tendency of wetness in late Holocene. The wet periods in eastern Qinghai-Tibet Plateau were longer than in the central and western regions. The comparative analysis reveals that the climate may have been mainly controlled by westerly circulation in arid northwestern China. But there were differences among the lake records in the timing of the beginning and end of the dry or humid periods as well as the intensity of the dry or wet conditions, which may be related to the strength of the Asian monsoon in the early Holocene and the influence of westerly circulation in the late Holocene. Furthermore, the insolation, global ice-sheets and topography of the Tibetan Plateau may have played important roles in controlling climate change in this area. The climate change in the East Asian monsoonmargin region is mainly influenced by the East Asian monsoon, which has also been recorded by the loess and desert deposits. The moisture conditions in the Qinghai-Tibet Plateau may have been controlled by the Indian monsoon, and the wetness in the early Holocene may be related to the strengthening of the Indian monsoon. Around 4 ka BP, a significant dry event commonly occurred in China's inland areas, which may be a global dry event that may have resulted in the decline of some ancient civilizations in the whole world.

Key words: China’s inland areas, climate change, Holocene, lake sediment

中图分类号: 

  • P92