Bioturbación en lagunas salinas (Lillo, Toledo)comparación con icnitas antiguas en rocas evaporíticas.

Abstract

The occurrence of living beings in saline lake environments can be deduced thanks to bioturbation structures present in sediment. A varied assemblage of bioturbation structures--which can be tied to specific sedimentary subenvironments--has been recognised in saline ponds of La Mancha (Lillo-Toledo). The main groups of traces of bioturbation include: traces of grass roots, traces of bush roots, burrows made by larvae of Diptera (Ephydridae), and burrows and borings made by bees and beetles, as well as traces of vertebrates. Comparing recent bioturbation structures with ancient ichnites (trace fossils and rhizoliths) found in evaporite facies of the Tertiary continental geological record of Spain allows refining of their characterization and interpretation within different sedimentary subenvironments. In fact, interpretations of ichnites made prior to direct comparisons with recent bioturbation structures largely coincide with those of recent traces of living beings. Therefore, the salt ponds of La Mancha can be considered as a good analog for Tertiary saline lakes of the Iberian Peninsula and subsequently for sedimentological analysis of ichnites.