| 引用本文: | 马龙,赵剑波,孙有斌.2013.黄土高原风尘沉积中石英结晶度的变化[J].地球环境学报,(2):1255-1260 |
| MA Long,ZHAO Jian-bo,SUN You-bin.2013.Variability of the crystallinity index of quartz from eolian deposits on the Chinese Loess Plateau[J].Journal of Earth Environment,(2):1255-1260 |
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| 摘要: |
| 中国北方的风尘沉积为研究区域构造隆升和全球气候变化提供了宝贵的材料。近20年来，尽管风尘沉积的古气候研究取得重大进展，但地质历史时期风尘的物源是否存在变化仍有很大争议。石英结晶度(CI)是黄土物源研究的可靠指标，本文用粉末X射线衍射仪对灵台剖面(~6.8 Ma—0)和庄浪岩心(~23.0—4.8 Ma)风尘沉积中石英结晶度进行了测量，发现灵台剖面石英的结晶度在时间序列没有明显的变化；庄浪钻孔的石英结晶度在~14.0—8.7 Ma明显的增大，表明风尘的物源在此存在变化。这种变化可能是由于此时段全球气候变冷和青藏高原隆升导致青藏高原东北部相对中亚造山带剥蚀量的增加引起的。 |
| 关键词: 黄土高原 风尘沉积 石英结晶度 物源变化 |
| DOI：10.7515/JEE201302003 |
| CSTR： |
| 分类号:P642.13+1 |
基金项目:国家自然科学基金项目(41072272)
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| Variability of the crystallinity index of quartz from eolian deposits on the Chinese Loess Plateau |
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MA Long1,2, ZHAO Jian-bo3, SUN You-bin1
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1.State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi′an 710075, China; 2.University of the Chinese Academy of Sciences, Beijing 100049, China;3.Department of Earth Sciences and Resources,University of Tibet, Lasa 850000,China
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| Abstract: |
| Eolian deposits in north China provides a precious material to study the regional tectonic uplift and the global climate change. Over the past two decades, although the loess research has made great achievements, the debate still existed on whether the loess provenance had changed during the geological past. Crystallinity Index (CI) of quartz, as a reliability index to trace the loess provenance, was measured for Lingtai(LT, ~6.8—0 Ma) and Zhuanglang(ZL, ~23.0—4.8 Ma) sections. The results show that the CI at Lingtai section doesn′t change significantly, whereas at Zhuanglang section it varies remarkably during ~14.0—8.7 Ma, indicating a signficant change of the dust provenance. Such a provenance change maybe caused by the increased denudation of the NE Tibet plateau comparing with central Asian orogen. |
| Key words: Chinese Loess Plateau eolian deposits quartz crystallinity index provenance change |
