摘要
隐仙溪扇体发育于大理盆地洱海西岸点苍山山前,扇体扇面坡度差别较大,内扇为10°,中扇6°,外扇2°,纵剖面呈下凹的楔形。通过野外观测及室内分析,将扇体沉积物划分为混杂堆积泥石相、无泥质砂砾石相、筛状沉积相和漂砾相,并对扇体不同亚相沉积物粒度分布特征进行对比分析,深入探讨了扇体沉积物粒度变化规律。认为其具有自内扇向外扇呈辐射状减小的趋势,且在根部粒度递减率高,向外递减率逐渐变低,这一变化规律可用对数函数曲线进行较好的拟合。
The alluvial fan of Yinxian stream is located between Erhai Lake and Diancang Mountain, in the Dali Basin, Yunnan province, which is 2.5km far from ancient Dali city. The surface gradient of the fan ranges from 10°at inner fan, to 6°at middle fan and 2° at outer fan. On the basis of field observation and indoor analysis, the sediment of the fan is classified into four kinds of lithofacies, i.e., intermixed mud-rock facies, sand-conglomerate facies without mud, cribrose lithofacies and boulder gacies. At the same time, the sediment-size ingredient of each subfacies is analyzed contrastively and the sediment-size variation law of the whole fan is analyzed in detail, which shows a radial decrease in the grain size from proximal to distal fan with the gradually diminishing velocity. This decreasing law can be fitted well by logarithm curve.
出处
《西南石油学院学报》
CSCD
北大核心
2006年第5期1-5,共5页
Journal of Southwest Petroleum Institute
基金
"十五"国家科技攻关项目(2001BA605A09)。
关键词
隐仙溪扇体
沉积结构
粒度分布
函数拟合
the fan of Yinxianxi
sedimentary texture
grain size distribution
function matching
Dali Basin
Yunnan
