干旱区研究

干旱区研究 ›› 2012, Vol. 29 ›› Issue (5): 920-925.

• 其他 • 上一篇    

渭河中游全新世晚期古洪水沉积物特征

 赵梅, 査小春, 黄春长, 庞奖励, 杨凌   

  1. 陕西师范大学旅游与环境学院，陕西 西安 710062
  • 收稿日期:2011-09-16 修回日期:2012-03-06 出版日期:2012-09-15 发布日期:2012-10-09
  • 通讯作者: 查小春. E-mail：zhaxch@snnu.edu.cn
  • 作者简介:赵梅（1985-），女，陕西宝鸡人，硕士，主要从事资源开发与环境演变研究.E-mail: zhaomei427@163.com
  • 基金资助:

    国家自然基金项目（41030637）；教育部博士点基金优先发展领域项目 (20110202130002)和中央高校基本科研业务费专项资金（GK200901007）资助

Analysis on Depositional Features of the Late Holocene Paleo-flood Slackwater Deposit in Middle Reaches of the Weihe River

ZHAO  Mei, CHA  Xiao-Chun, HUANG  Chun-Chang, PANG  Jiang-Li, YANG  Ling   

  1. College of Tourism and Environmental Sciences, Shaanxi Normal University, Xi’an 710062, China
  • Received:2011-09-16 Revised:2012-03-06 Online:2012-09-15 Published:2012-10-09

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被引次数

18

摘要： 通过野外实地调查，在渭河中游咸阳市南寺村一级阶地的全新世黄土-古土壤剖面，发现了含有波状水平层理的古洪水滞流沉积层，对所采集的全新世地层样品进行了粒度、磁化率、烧失量、CaCO3和石英颗粒微结构表面特征分析，表明古洪水滞流沉积物（SWD）平均粒径小，磁化率值低，CaCO3含量高，石英颗粒表面“V”形坑和三角痕明显等特征，与风成黄土和古土壤差别显著，判定为典型的古洪水滞流沉积物。通过OSL（光释光）测年及地层学对比，确定古洪水SWD记录了渭河中游3 200~2 800 aBP发生的一组3次古洪水事件，正处于全新世大暖期向晚期转变的过渡时期，气候不稳定，降水变率大，引发了连续的特大洪水事件。此研究成果对于揭示区域水文变化对全球气候变化的响应规律具有重要科学意义。

关键词: 全新世, 古洪水事件, 黄土-古土壤剖面, 沉积物, 气候变化, 咸阳, 渭河中游

Abstract: Based on the field investigation, a Holocene paleo-flood slackwater deposit (SWD) in a Holocene loesspaleosol profile was found in middle reaches of the Weihe River Basin. The grain size, magnetic susceptibility, CaCO3, loss-on-ignition and surface micro-structure of quartz grains were analyzed in laboratory. The results showed that the properties of SWD were different from those of loess and paleosol. This SWD is identified as the most typical Holocene paleoflood deposit. According to the OSL dating and stratigraphy comparison, the age of the SWD was identified during 3 200-2 800 aBP, which just was the transition period from the mid-Holocene climatic optimum toward the late Holocene dry conditions, and the unstable climatic system and the weakening summer monsoon brought out a sharp change of precipitation and caused the occurrence of extreme paleo-flood. This study results are of great scientific significance in understanding the local hydrology change response to global change.

Key words: Holocene, paleo-flood event, loess-paleosols profile, Slackwater deposit, climate change, Xianyang, Weihe River