泥河湾盆地马圈沟剖面早更新世矿物变化特征及其古环境意义
Characteristics of Main Minerals at Majuangou Profile in the Nihewan Basin During Early Pleistocene and It’s Paleoenvironment Significance
投稿时间:2018-07-26  修订日期:2018-09-05
DOI:
中文关键词:  泥河湾盆地  马圈沟剖面  碎屑矿物  碳酸盐矿物  热磁分析
英文关键词:Nihewan Basin  Majuangou profile  detrital minerals  carbonate minerals  Thermomagnetic analysis
基金项目:研究所135培育项目(Y560031008)资助.
作者单位邮编
孙爱军 中国科学院青海盐湖研究所 810008
高东林 中国科学院青海盐湖研究所 810008
张岩 青海省有色地质矿产勘查局八队 青海 西宁 
任倩慧 中国科学院青海盐湖研究所 
刘秀婷 中国科学院青海盐湖研究所 
袁小龙 中国科学院青海盐湖研究所 
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中文摘要:
      摘要:在野外考察采样的基础上,对马圈沟剖面更新世河湖相沉积序列进行了XRD矿物组分和磁性矿物分析。研究发现:剖面沉积矿物主要由碎屑矿物和碳酸盐矿物组成,碎屑矿物主要为石英、钠长石、白云母、斜绿泥石,其平均含量分别为38.78%、17.16%、29.63%、4.10%,是剖面沉积矿物组成主体,且各矿物之间基本没有相关性;相对于碎屑矿物,碳酸盐矿物在整个剖面中含量较低,主要为方解石和白云石,其含量分别为4.72%、3.59%,文石在剖面中零星出现,软体动物介壳是其主要来源。进一步对来自剖面典型样品进行热磁分析,有效的确定了沉积物中磁性矿物的种类以及加热过程中磁性矿物的变化过程和产物,并对其来源进行了探讨。同时发现,含绿泥石较高的灰绿色粉砂样品加热后磁化率的升高幅度比灰黄色样品高,而绿泥石的相对含量与该地区化学风化密切相关,进一步说明热磁分析(尤其是k-T曲线)的变化特征可以用来反应泥河湾盆地化学风化作用强度的变化,具有重要的古环境意义。
英文摘要:
      Abstract: Based on the field investigation and systemic samples collected at Majuangou profile, selected 67 samples by equal intervals of 1m to XRD mineral component analysis, establish characteristic of minerals and paleoenvironment relationship of Nihewan basin in the early Pleistocene. The results show that the sedimentary minerals were major component of detrital minerals and carbonate minerals. Detrital minerals were dominated the profile sedimentary mineral and composition with quartz,sodium feldspar, dolomite and plagioclase, the mean values of 38.78%, 17.16%, 29.63%, and 4.10%, respectively. Each of the detrital minerals were hardly have the correlation.The carbonate minerals have low content in the section and major component by the calcite and dolomite, with the content of 4.72% and 3.59%, respectively. It has a few of aragonite in the profile, the source of aragonite was from the mollusk shells. Coupled with thermomagnetic analysis, the grayish-green silt samples generally have higher contents of chlorite and more enhanced magnetic susceptibility after heating than the grayish-brown silts samples. In addition, the contents of chlorite were closely positive correlation with the chemical weathering in the study areas, supported that the variation characteristics of thermo-magnetic analysis (especially k-t curve) can be used to reflect the intensity variation of chemical weathering in the Nihewan Basin. It was important paleoenvironmental significance.
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