New petrified forest in Maranhão, Permian (Cisuralian) of the Parnaíba Basin, Brazil
Abstract This work presents a new fossil plant-bearing area located in the municipalities of Duque Bacelar and Coelho Neto, Maranhao State, Brazil, recovered from lower Permian (Cisuralian) strata of the Pedra de Fogo Formation, northeastern portion of the Parnaiba Basin. The area comprises more than five exposures with assemblages formed mostly of large gymnosperm woods, a number of them in life-position (reaching up to ∼2.30 m in height and 1.15 m in diameter) and, in lesser degree, of horizontal tree-fern stems (up to 5 m in length), some of them being referable to Psaronius sp. The fossils are recorded in sedimentary beds of continental origin that accumulated in shallow, nearshore areas of large lakes, which eventually were affected by rapid burial episodes generated by non-channelized, high energy fluvial systems. The new fossil assemblages are included within lacustrine rocks placed at the base of the Pedra de Fogo Formation, i.e., Silex Basal Member, near the contact with the underlying Piaui Formation (Pennsylvanian). This observation contrasts with previous studies at the southwestern portion of the basin, where the stratigraphic position of plant fossils is referred to the upper Pedra de Fogo Formation (Trisidela Member) or even to the overlying Motuca Formation. The new sites currently suffer damage from human activities and require urgent actions in order to protect them. Based on the current laws, some measures of protection for these sites are discussed and proposed herein.