Fragipan formation in argillic brown earths (Fragiudalfs) of the Milfield Plain, north-east England. I: Evidence for a periglacial stage of development
Fragipan formation in argillic brown earths (Fragiudalfs) of the Milfield Plain, north-east England. I: Evidence for a periglacial stage of development
复制标题
英格兰东北部米尔菲尔德平原的泥质棕土（Fragiudalfs）中的 Fragipan 地层。
DOI：
--
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
R. Payton
中科院分区：
文献类型：
--
作者：
R. Payton
总结
在这三篇论文的第一篇中，描述了类似于美国东北部的fragipans土壤的母质、形态和田间关系，并分析了它们的化学和物理性质，以支持冰缘发育阶段。土壤材料受到冰缘过程的影响，包括冰楔的形成，其年龄是根据埋藏的古土壤确定的。碎屑岩的细土体积密度介于1.75和1.91 g cm−3之间，而上覆的Eb层的密度小于1.40 g cm−3。脆盘的致密透镜状结构和多边形裂隙的形成归因于洛赫湖Stadia 1 11 000 - 10 000年B. P.期间的永久冻土的存在。确定了Fe和Mn从裂隙充填物和裂隙壁中溶出形成的灰色多边形带的位置，氧化还原过程粘土从Eb层向碎屑层的迁移非常明显。粘土和淤泥也从灰色区域的上部局部移走，并向其下部重新沉积。类似的结构退化影响了上部碎屑岩的残积袋。冰缘过程充分解释了宏观构造特征的成因，但不能解释脆性盘的独特一致性。
SUMMARY
In this first of three papers, the parent materials, morphology and field relationships of soils with fragipans, similar to those in north-eastern United States, are described and analyses of their chemical and physical properties are presented to support a periglacial stage of development. The soil materials have been affected by periglacial processes, including ice-wedge formation, the age of which has been established by reference to a buried paleosol. The fine earth bulk density of the fragipans is between 1.75 and 1.91 g cm−3 whereas the density of overlying Eb horizons is < 1.40 g cm−3. The formation of the compact lenticular structures and polygonal fissuring of fragipans is ascribed to the former presence of permafrost during the Loch Lomond Stadia1 11 000 to 10 000 years B.P. The polygonal fissures, after subsequent infilling with illuvial material, have determined the position of the greyish polygonal zones which have formed by the eluviation of Fe and Mn from fissure infill and fissure walls by redox processes. Clay migration from the Eb horizon into the fragipan is well marked. Clay and silt have also been locally removed from the upper parts of the greyish zones and redeposited towards their lower parts. Similar textural degradation has affected eluvial pockets in the upper fragipan. It is concluded that periglacial processes fully explain the genesis of macrostructural features but not the distinctive consistence of the fragipan.