A new formation process for calcic pendants from Pahranagat Valley, Nevada, USA, and implication for dating Quaternary landforms

It has been assumed that soil pendants form in a similar manner as stalactites, in which innermost laminae are the oldest and outer laminae are the youngest. This study presents a new interpretation for soil pendant development. Pahranagat Valley, Nevada, pendants contain features indicating continued precipitation through time at the clast-pendant contact, implying that the oldest deposits are not always found at the pendant-clast contact, as other studies have assumed. These features include a void at the clast-pendant contact where minerals such as calcium carbonate, silica, and/or fibrous silicate clays precipitate. In addition, fragments of the parent clast and detrital grains are incorporated into the pendant and are displaced and/or dissolved and result in the formation of sepiolite. This study indicates that pendants are complex, open systems that during and after their formation undergo chemical changes that complicate their usefulness for dating and paleoenvironmental analyses. (c) 2005 University of Washington. All rights reserved.