Paleopedologic interpretations of soils buried by tertiary and Pleistocene-age volcanic ashes: Southcentral Kansas, Western Oklahoma, and northwestern Texas, U.S.A.

Abstract

Deposits of volcanic ash from major eruptions during the late Tertiary and early-to-middle Pleistocene in the western U.S. are interbedded with unconsolidated sediments in parts of Oklahoma, Kansas, and Texas. Soils and sediments at the land surface at the time of the eruptions were buried by the relatively pure (>95% glass shards) ash. The former surface soils, or paleosols, contain information about soil-forming processes, climates, and landscapes of the region prior to and at the time of the eruptions. Field descriptions of the paleosols are made using pedologic nomenclature. Comparisons are made of paleosols buried by deposits of ash from the same eruption, paleosols buried by deposits of ash from eruptions of different age, and paleosols buried by ash and soils described at the land surface today. Paleosols buried by ash exhibit a diversity of characteristics. Ash from eruptions occurring hundreds of thousands to more than a million years apart buried paleosols which have common characteristics. Paleosols buried by ash resemble soils at the land surface in the region at present. Climates and landscapes of today are inferred to be similar to climates and landscapes at the times of the Tertiary and early to middle Pleistocene volcanic eruptions.