Accumulations of Ferganites (Fusulinacea) in shallow turbidite deposits from the carboniferous of Spain

As occurs commonly in upper Kasimovian and lower Gzhelian strata from sever al parts of Eurasia, the lower part of the Puentelles Formation (Cantabrian Zone, NW Spain) contains high concentrations of reworked Ferganites tests. No other large fusulinacean taxa are recorded in these beds, which are int erpreted as shallow turbidite deposits derived from flood-dominated fan-del ta and river-delta systems. These alluvial to shelfal lobes developed in a tectonically active setting and were located in the proximal sectors of a m arine carbonate ramp, with hyposaline water conditions. In contrast, the upper member of the Puentelles Formation contains more var ied fusulinacean assemblages, including Ferganites and other large fusulina ceans. This upper part is characterized by diverse biota, skeletal wackesto ne deposits with abundant boundstone intervals (algal bafflestones and mud mounds), and represents the gradual backstepping from detrital lobes and re -establishment of normal marine conditions, lacking elastic influx from the hinterland. The Ferganites species occurring in the lower member seem to have lived in near-shore, high-energy environments in which their durable morphology was advantageous. These forms seemingly were well adapted to relatively low sal inity conditions, which otherwise greatly restricted faunal diversity. Four Ferganites forms from the lower member of the Puentelles Formation (in cluding a new species, Ferganites martinezi) are described.