The outcrop near the town of Blanquillo

PORTILLO, NATALIA S.; SICCARDI, ARÓN; BLANCO, GONZALO; URIZ, NORBERTO JAVIER; CINGOLANI, CARLOS ALBERTO

Planet Earth - In deep time. Palaeozoic Series. Devonian & Carboniferous

Schweizerbart'sche Verslagsbuchhandlung

Lugar: Stuttgart; Año: 2016; p. 216 - 217

The Durazno Group, in the central region of Uruguay, records a clastic transgressive-regressivbe sedimentary cycle during the Early Devonian in the southern secotr of the intracratonic Paraná basin. The sedimentary process was in a siliciclastic shallow marine shelf during cold water event. At the base of the group, the Cerrezuelo Formation consists of feldespar dandstones, arkoses amd kaolinitic pelites, in a fining-upward sequence. The unit record ichnofossils and some land plants. The facies associatons have shown littoral-sublittoral with fluvial influence environments. The El Cordobes Formation consists of kaolinite white-grey argillaceous shales that record the maximum flooding of the transgressive event, bearing marine invertebrates associated with the Malvinokaffric realm (brachiopods, bivalves, gastropods, trilobites, connularids, echinoderms, worms and palynomorphs), trace fossils and fishes are also present that define the Early Devonian age. The sedimentary sequence records a shallow marine to deep sublittoral environment. The upper part of the group is composed of the La Paloma Formationwith shales, sandstones and conglomerates in a clear coarsening-upward sequence that records a shallowing upwards event at the depocentre. Some invertebrates are also present. The deposition ocurred during the regressive cycle of the Devonian sea that culminated in littoral conditions.