Carbonate ramp facies at the Calabozo Formation (Middle Jurassic), Mendoza, Argentina

the limestones of the calabozo formation of early callovian age, crop out in the neuquén basin, southwestern mendoza province, argentina. facies/microfacies analysis at arroyo el plomo, west of malargüe, shows that the limestones of the calabozo formation originated during a transgressive /regressive episode over the delta-margin facies of the lajas formation (late bajocian-callovian), with a change from siliciclastic to carbonate sedimentation. an extensive layer of floatstone marks the beginning of this stage. within a ramp environment, a well represented mid-ramp subenvironment can be distinguished, consisting of a subtidal facies arrangement (wackestones, packstones, packstones with channels and floatstones) and an inner ramp subenvironment, characterized by a system of ooidal bars (grainstones) with tidal channels (floatstones) and predominantly intertidal facies passing into peritidal, and supratidal facies (boundstones). three shallowing-upward cycles were recognized, the lower and middle ones being characteristic of the mid- ramp. the upper cycle is the best developed and consists of a middle ramp lower hemicycle and an inner ramp upper hemicycle. the calabozo formation is capped by deposits corresponding to a supratidal environment with restricted circulation, on top of which the evaporitic succession of the early callovian tábanos formation is developed