| A lithosequence of lamellae soils derived from volcanic parent materials was described in the Jemez Mountains. The parent materials studied were alluvial/colluvial tuff (Tt), alluvial/colluvial rhyolite (Rt), pumice (Pr), residual tuff (Tr), and lacustrine sediments (Lt). Morphology, micromorphology and physical, chemical, and mineralogical characterization were used to determine if lamellae characteristics differ with lithology. Additional objectives were to hypothesize on the genesis of lamellae, and to determine placement of the soils within the ICOMAND (International Committee on the Classification of Andisols) classification scheme.;In the pedons derived from Tt, Rt, and Pr, lamellae are roughly parallel to the soil surface and differ from interlamellae in redder color, firmer consistence, presence of oriented clay, and higher bulk density, clay, organic carbon, and free iron contents. Lamellae in pedons from the Tr and Lt materials had different thickness, orientation, and chemical composition than classical lamellae. Weathering and the concentration of secondary minerals are frequently greatest in lamellae. Differences in lamellae morphology, mineralogy, and physical characteristics are related to lithology, parent material transport, and/or degree of profile leaching.;Amorphous components make up only a small portion of the soils. Based on the latest ICOMAND proposal, taxonomic placement reflecting the volcanic origin of the sampled pedons is limited to the subgroup level (Vitrandepts) and/or the family level (ashy, whole soil-mineralic (volcanic glass)) and only in the Tt, Rt, Pr, and Tr pedons.;Illuviation is the major process acting in lamellae formation. Textural stratification has contributed to initiation of lamellae. The presence of permafrost and formation of ice lenses during the Pleistocene may have advanced lamellae formation. Iron oxide lamellae of the Lt pedons are formed under the influence of a fluctuating water table controlled by Pleistocene climatic shifts. |
