Geochemical transect through a travertine mount: A detailed record of CO2-enriched fluid leakage from Late Pleistocene to present-day – Little Grand Wash fault (Utah, USA)

Active and fossil endogenic travertine mounts scattered along the Little Grand Wash fault are studied as records of Quaternary CO2-enriched fluid leakage. This study focusses on a particular area where a fossil mount formed in a near-surface setting by successive circulation/sealing episodes from Late Pleistocene to Mid-Holocene and where a modern surface travertine is still being formed by a CO2-enriched fluid source. The fossil mount is composed of horizontal and vertical veins whereby the vertical veins recorded numerous cycles of circulation/sealing/dissolution events and were used as conduits for the CO2-enriched fluid circulation from the depth to the surface or along sub-horizontal fractures where successive precipitation events are recorded. The modern travertine is being built at the surface by successive eruption of Crystal Geyser, an anthropic geyser active since the 1930's.