An investigation of two landscapes on the Holston limestone formation in McMinn County, Tennessee

The locally called "Red Hills" of McMinn County, Tennessee are underlain by the Holston geologic formation which form dark red soils that contain high amounts of iron oxides and are highly weathered. Very little study has previously been conducted on these unique soils. The objectives of this research were to 1) describe and classify ten soil profiles on two different landscapes on the Holston geologic formation, 2) relate soil weathering to soil and geologic properties and mineralogy, and 3) develop a landscape and soil genesis model for this area in McMinn county. Two toposequences were chosen with four representative profiles on each. Two adjacent flood plains were included in the study. Standard soil survey laboratory procedures were used to analyze the samples for complete characterization. Classification of the flood plain soil profiles were coarse-loamy, siliceous, superactive, thermic Oxyaquic Dystrochrept and fine-loamy, siliceous, semiactive, thermic Oxyaquic Dystrochrept. The two ridge crest soil profiles classified as fine, parasesquic, thermic Typic Hapludult and fine, parasesquic, thermic Typic Rhodudult. The soil on the shoulder landscape position of the Daughtery Knob transect classified as a fine, parasesquic, thermic Rhodic Paleudult. The two back slope soil profiles of the Prospect transect were classified as fine-loamy, parasesquic, thermic Typic Rhodudults. The lower side slope soil of the Daughtery Knob transect was a coarse-loamy, siliceous, semiactive, thermic Typic Dystrochrept. The two foot slope soils classified as fine-loamy, siliceous, semiactive, thermic Typic Hapludalf and fine-loamy, parasesquic, thermic Rhodic Paleudult. Darker, redder colored soils contained more iron oxides and kaolinite. Hematite was more lithogenic than pedogenic. The more stable landscape positions, the ridge crest soils, contained the highest concentrations of iron oxides and kaolinite showing that they are the most highly weathered.