Mixed carbonate-siliciclastic sedimentation in a mesoproterozoic storm-dominated ramp: Depositional processes and stromatolite development

Records of shallow-marine ramps with the mixing carbonate and siliciclastic sediments are common throughout geological time. All these records have pure deposits as end members, occurring contemporaneously in distinct depositional regions along ramp, transitional hybrid facies between them. The two member can mix different scales alternate time due to climatic changes regressions transgressions. This work presents a detailed reconstruction Mesoproterozoic storm-dominated mixed carbonate-siliciclastic ramp composed whithout presence or deposits, rare example record. Based on high resolution logged section (in 1:20 scale) qualitative thin sections, eleven lithofacies were identified grouped into three associations (offshore, offshore transition shoreface), which stacked vertically forming transgressive–regressive cycle. faciological distribution indicates low relief wide microbial colonization from shallow relatively deep waters (below storm-wave base level). In low-energy distal areas, mats spread laterally over large distances little no interference currents, while morphology bioherms is shaped by currents induced waves. turn, wave energy shoreface inhibits formation stromatolites, restricting their occurrence layers carpets intraclastic lags. occurs compositional scale homogeneous whole interval, independent shifts associations. homogeneity linked regularity input during sedimentary accumulation. Strong storms allow transport grains generated basin fair-weather periods.