TRIASSIC PLANTS AND THEIR RELATIONSHIPS WITH THE VOLCANISM IN THE AGUA DE LA ZORRA FORMATION, MENDOZA PROVINCE, ARGENTINA. Fosssil plants were recovered from the upper levels of the Triassic Agua de la Zorra Formation, Cuyo Basin, Mendoza Province, Argentina. The formation represents a fluvio-lacustrine environment affected by volcanism. The plant assemblage is dominated by Corystospermales (Dicroidium, Johnstonia and Xylopteris), with subordinate Equisetales and Osmundales. Abundant amorphous organic matter, together with scarce botryoidal colonies of the green algae Botryococcus are also present in the plant bearing levels. Notwithstanding the fact that strata yielding fossil plants are commonly associated with basaltic peperites, the kerogen of these levels displays low to moderate thermal alteration, suggesting that the sediments of the bottom were not extensively unsettled by the episodic entrance of basaltic lava in the freshwater body.