Fig. 3: Example channelised packages and inclined accretionary surfaces.
From: Sustained fluvial deposition recorded in Mars’ Noachian stratigraphic record
a Close up of white box indicated in Fig. 2b. b Architectural interpretation of a displaying a number of channels (blue lines). Some examples preserve former channel margins, strong evidence for original channel lateral migration. Channelised packages have associated inclined accretion surfaces (magenta lines), with all packages topped and floored by more extensive fifth-order surfaces (red lines). Fifth-order surfaces possibly archive avulsion events. A previous channel margin (1 + 3) laterally coalesces with the final channel margin (2 + 4) indicating that the original active channel migrated laterally. A nested channel-cut (5) is present within a larger channelised package. c Close up of white box indicated in Fig. 2b. d Examples of inclined accretion surfaces with distinct foreset and bottomset elements (topsets truncated by overlying strata). Downlapping of internal, third-order surfaces suggest multiple accretion phases. Note that line drawings are not attempted in areas where exposure is poor. A third-order surface (7) downlaps the bottomset of an underlying fourth-order surface (6) indicating bar migration. A subsequent fourth-order surface (8) truncates the previous fourth-order surface (6) indicating multiple phases of bar-building activity.
