OSL Dating of the Sediment Stratigraphy of the Lajia Ruins in the Guanting Basin in the Upper Yellow River Basin
详细信息
- 责任者：Zhang Yuzhu (College of Tourism and Environmental Sciences ; Shaanxi Normal University ; Xi’an 710062 ; China) ; Huang Chunchang
- 刊名：Acta Geographica Sinica
- 出版年：2013
- 卷期：68(5)
- 关键词：地质遗迹 ; geological relics ; 光释光测年 ; optical stimulated luminescence dating ; 第四纪 ; Quaternary ; 黄河 ; Yellow River
- 页码：p.626-639
- 图表：illus., 2 tables, 48 refs.
- 分类号：1400
- issnNo：ISSN0375-5444
- isbnNo：CN11-1856/P
摘要
The palaeo-ground of the Qijia Culture in the Lajia Ruins was found to be broken by several groups of earthquake fissures.One layer of conglomerated clayey mudflow deposit has blanketed the Lajia Runis and filled with the earthquake fissures.After detailed field observations,samples for OSL dating were taken from the sediment profile.OSL ages of the samples were obtained by using the single-aliquot regenerative-dose method.A chronological framework was established in the XLJ profile based on the OSL ages and in combination with the 14 C ages and stratigraphic correlations,which indicates that the second terrace of the Yellow River was formed at 35.00 ka BP.Then,accumulation of the eolian loess-soil profile started.The red clayey mudflow deposit and the earthquake fissures were formed at 3.95 ka BP in the second terrace in the Guanting Basin.Sedimentary samples were taken from the profile and magnetic susceptibility and particle-size distribution were analyzed in the laboratory.The results show that the Malan loess(L 1-1) was deposited during 35.00～11.50 ka BP.It was accumulated by dust storms and dust falls under a dry-cold environment during the late last glacial without being modified by pedogenesis.The transitional loess(L t) was dated to be 11.50～8.50 ka BP.It was slightly affected by weathering and pedogenesis during the early Holocene because the climate was dry.The palaeosol(S 0),i.e.,Heilusol or Chernozem,was dated to be 8.50～3.10 ka BP.It was strongly affected by weathering and pedogenesis during the mid-Holocene Climatic Optimum.However,a layer of conglomerated red clayey mudflow,which blanketed the Lajia Ruins at 3.95 ka BP,made the palaeosol(S 0) split into two sub-layers(S 0-lower and S 0-upper).