Genesis and morphology of soil pendants in Quaternary landforms of Pahranagat Valley, Nevada
Abstract
Five geomorphic surfaces present in the northern Pahranagat Valley, Lincoln County, Nevada range in age from Early Pleistocene to Recent (Q1--Q5) and vary in clast lithology from dolomite to volcanic tephras. Two chronosequences and 5 lithosequences were compared to evaluate micro and macromorphic characteristics and development of soil pendants. This study presents a new interpretation for soil pendant development. Key features observed in the Pahranagat Valley pendants provide evidence for precipitation at the clast-pendant contact suggesting that newer deposits are not always found at the pendant terminus as other studies have assumed. These features include a void at the clast-pendant contact where precipitates such as calcium carbonate, silica and/or fibrous silicate clays may precipitate. Other features present in these pendants include significant amounts of parent clast grains that are incorporated into the pendant, detrital grain and parent material displacement and/or dissolution and presence of the fibrous clay sepiolite.