3. Stratigraphy Assume that the five wells A to E are from a siliciclastically dominated basin. The horizontal distance between each well is few kilometeres. For each well, the left curve

is a gamma-ray log and the right one is a sonic log. Fluvial deposits are dotted and shallow-marine ones are white. The black line is a marker bed that has been defined as a time horizon with palaeontological data. 3a. Correlate the wells lithostratigraphically. 3b. Mark positions of discordances. 3c. Can any of the fluvial sediment bodies be used as time markers? If yes, which one(s)? Explain your answer.