To try and determine the significance of thinning-upward sequences, two turbidite sections in the Monte Modino Formation (Oligocene, Northern Apennines, Italy) were studied. The two sections are geographically and stratigraphically several hundred meters apart. One section, consisting of a geometrically definable channel cut into an olistrostrome contains thinning-upward sequences. The second section comprises thinning-upward cycles which alternate with portions of the sequence with no regular changes in bed thicknesses. Comparison of these Oligocene rocks with modern deep-sea deposits and subaerial fans suggests that thinning-upward sequences may form in channels and valleys which need not necessarily be erosional ones. Thus, these sequences may indicate shifts of thalwegs of flows as a response to partial plugging of depressions.

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