TY - JOUR AU - Campetella, Débora Mical AU - Carmona, Noelia Beatriz AU - Ponce, Juan José AU - Wetzel, Andreas AU - Rodríguez, Maximiliano AU - Parada, Martin Nazareno PY - 2020/09/30 Y2 - 2024/03/28 TI - Trace fossils as tools to unravel oxygen conditions: A case study from Los Molles Formation (Toarcian-lower Callovian) JF - Revista de la Asociación Geológica Argentina JA - RAGA VL - 77 IS - 3 SE - DO - UR - https://revista.geologica.org.ar/raga/article/view/221 SP - 463-477 AB - <p>The Toarcian – lower Callovian Los Molles Formation in the Chacay Melehue section (southern limb of Cordillera del Viento - Neuquén Basin) comprises offshore-shelf deposits and subordinately, channel-levee and lobe deposits produced by density currents. These deposits are characterized by two distinctive trace fossil suites: (1) <em>Chondrites </em>and <em>Trichichnus </em>in the offshore-shelf mud, and (2) <em>Chondrites,</em> <em>Trichichnus, </em>and <em>Phycosiphon</em> occurring in distal levee deposits. The generally low diversity and abundance of the trace fossils suggest severe environmental conditions. In particular, in the intervals containing <em>Chondrites</em> and <em>Trichichnus, </em>pyrite framboids are abundant and most likely indicate low oxygen availability within the sediment. The presence of <em>Phycosiphon</em> in the levee deposits implies short periods of improved oxygenation caused by the density currents originating in shallow water.</p> ER -