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地质力学学报:2007,13(4):322-332,314
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庐山地区第四纪泥砾沉积物的成因探讨
(1.中国地质科学院地质力学研究所, 北京 100081;2.国家地质公园规划研究中心, 北京 100081;3.庐山风景名胜管理局国土资源局, 江西 九江 332900)
ORIGIN OF QUATERNARY MUDDY GRAVEL DEPOSITS IN THE LUSHAN AREA
(1.Institute of Geomechanics, Chinese Academy of Geological Science, Beijing 100081, China;2.Chinese Research Center of National Geopark, Beijing 100081, China;3.Lushan Administrative Bureau, Jiujiang 332900, Jiangxi, China)
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投稿时间:2007-07-30    
中文摘要: 庐山第四纪泥砾沉积物的砾石组构特征表明,砾石岩性与山体基岩基本一致,砾石的等体积球径较小,加权平均砾径较中值砾径大,分选系数大于1,分选性差,φ值相对较小,平均为0.66,F值相对较大,在2左右,F/φ比值介于2.75~4.75,ρ值集中且较小,为22.75%~37.75%,砾石以棱角、次棱角状为主,磨圆较差;a轴和ab面都倾向沟谷下游,a轴倾角集中且较小,为7~8°,ab面倾角为7~21°,a轴较ab面具有更为优势的组构倾向;沉积物粒度频率曲线在4~5ϕ范围内表现为峰;石英砂颗粒为次棱角状,贝壳状断口发育,具平行擦痕、上翻解理片、V形坑和硅质沉淀。上述沉积学特征表明庐山第四纪泥砾沉积物系冰碛冰水沉积,而非泥石流或河流堆积。
中文关键词: 庐山  泥砾  组构特征  冰碛物
Abstract:The gravel fabric characteristics of Quaternary muddy gravel deposits in the Lushan area indicate the following:the lithology of gravels is almost consistent with that of bedrocks in the mountains; the isometric sphere diameter of gravels is small, the weighted average diameter of gravels is lower than the median diameter of gravel;the gravels are poorly sorted with a sorting coefficient of >1;the values are relatively lower, averaging -0.66;the F values are higher, being 22.75%-37.75%;the ratios of F/φ range from 2.75 to 4.75;the φ values are lower and concentrated, ranging from 22.75 to 37.75%, and the gravels are mainly angular and subangular.Both the a-axis and ab-plane dip towards the downstream, the dip angles of the a-axis are low and concentrated, being 7 -8°, the ab-plane dips at 7~21°, and the a-axis has more preferred dip of fabrics than the ab-plane;the peak of the grain-size frequency distribution curve of deposits in the Lushan area is in the range of 4 and 5φ;The quartz sand grains are subangular and have well-developed conchoidal fractures, parallel striations, upturned cleavage flakes, "V" -shaped holes and siliceous deposits.The above-mentioned sedimentary characteristics indicate that the Quaternary muddy gravel deposits in the Lushan area should be till and glaciofluvial deposits rather than fluvial deposits or mudflows.
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刘宗秀,赵志中,田姣荣,等,2007.庐山地区第四纪泥砾沉积物的成因探讨[J].地质力学学报,13(4):322-332,314.DOI:
LIU Zong-xiu,ZHAO Zhi-zhong,TIAN Jiao-rong,et al,2007.ORIGIN OF QUATERNARY MUDDY GRAVEL DEPOSITS IN THE LUSHAN AREA[J].Journal of Geomechanics,13(4):322-332,314.DOI:

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