Primeras aportaciones a la Paleoicnología del grupo Murero (Cámbrico inferior-medio) en Murero. (Provincia de Zaragoza. Cadena Ibérica Occidental)

Resumen

The distribution of occurring ichnotaxa along the «rambla de Valdemiedes -1 » section (RVi), Murero Croup, locality of Murero (Occidental Iberian Chain; province of Zaragoza, Spain) and ils relations with the biofacies are analized. The term ichnoassociation is defined, and four palichnological units are established; they are represented by a total of three ichnoassodations, each contents of wichis described. These are the aff. Planolites (in Valdemiedes and Mansilla formations), Planolites montanus (in part of the Valdemiedes formation) and a ff. Planolites and Diplichnites ichnoassociations (In Murero formation). The aff. Planolites and Diplichnites ichnoassociation développes in more diversified ecosystems than the aff. Planolites ichnoassociation do, of wich the former is derived. This evolution, binded to a generalized transgressive trend, is interrupted by the establishment in the uppermost Lower Cambrian of the Planolites montanus ichnoassociation. This one is interpreted as a product of the environmental and ecological crisis caused by the Valdemiedes geoevent.