ABSTRACT

Analysis of Hubert's criteria (1966, p. 696) for recognition of graded beds deposited by across slope flowing "ocean bottom currents," rather than turbidity currents, in flysch-type marine basins, suggests that too much reliance is placed on discordance of paleocurrent and paleoslope directions. The demonstration that bottom currents depositing graded beds flowed at high angles to the direction of the independently determined paleoslope only excludes the turbidity current hypothesis if it can be convincingly demonstrated that the paleoslope in question actually extended across the path of paleocurrent flow at the time of flow. Interlayering of sequences of graded beds with slumped sediments whose line of movement was across that of the flow of the bottom currents which deposited the g aded beds may be thought to indicate across-slope current flow. However, even this criterion becomes suspect if there is a possibility that, for example, the slumped sediments moved beyond the lower limit of the paleoslope on which their movement was initiated, or that the basin's floor and slopes showed antipathetic fluctuations in extent with time.