Late Miocene ant nests and associated ichnofossils from paleosols: The Cerro Azul Formation at Salinas Grandes de Hidalgo, La Pampa, Argentina

RICARDO NESTOR MELCHOR; GRACIELA VISCONTI; CLAUDIA MONTALVO

SLIC 2013 Abstracts and Intra-symposium Fieldtrip Guidebook

INCITAP - Facultad de Ciencias Exactas y Naturales (UNLPam)

Lugar: Santa Rosa; Año: 2013; p. 75 - 89

During the fieldtrip we will visit Salinas Grandes de Hidalgo, a classic locality for Miocene fossil vertebrates of Argentina. The locality is also significative for paleosol ichnology because this was the place where Laza (1982) described the first fossil ant nest, Attaichnus kuenzelii. The trace fossil bearing outcrops were referred as belonging to the Epecuén Formation by Laza (1982) following Pascual et al. (1965), however, they are now considered as part of the Cerro Azul Formation (Goin et al., 2000). The ants proposed as producers belong to the fungus-growing tribe Attini and some relevant paleoenvironmental and paleocological inferences were made on the basis of the finding (see also Genise et al., 2013). These fossil ant nests are very abundant in outcrop today and we will revise this trace fossil in addition to other ichnofossils from paleosols. Besides the paleontological and ichnological meaning of the locality, the saline lake is commercially exploited to produce sodium chloride essentially in the form of table salt. After harvesting the salt is accumulated in mounds near the saline lake before further processing.