Channel Deposits


When seen in cross-section, channels have elliptical profiles and are filled with sediment that is generally coarser than the surrounding rock. They also cut into (by erosion) the underlying rock. Channel deposits indicate running water: they form on alluvial fans, in rivers, on deltas, even in submarine fans.

FLUVIAL CHANNELS

Series of fluvial channels incised into over-bank beds. Close-up of central portion of picture on left; with possible gamma-ray log character and incision surfaces shown.

 

   

 

Channel down-cutting into abandonment/overbank mudstones. Abrupt transition from overbank, coaly shales to coarse, channel sand.

 

Delt-Mouth Bar, Kentucky, USA: Note Incised Surface Of Reworked Bar Flood delta channels incising into barrier-island deposits: Kentucky, USA

 

Strongly incised channel cutting down into coarser, sandy deposits and filled with predominantly fine-grained material, possibly mouth-bar.

 

Channel Point-Bar with low-angle incision at base.

 

Tidal, Storm or Tsunami Channel: Note Incised Surface Beneath Channel. Tsunami Incision, Load & Drape - Kentucky, USA: Note Uniform Thickness of Layer.

ALLUVIAL CHANNELS

When seen in cross-section, have elliptical profiles and are filled with sediment that is generally coarser than the surrounding rock. They also cut into (by erosion) the underlying rock. Channel deposits indicate running water: they form on alluvial fans, in rivers, on deltas, even in submarine fans.Left: Channel (red arrow) Hammer (circled) shows scale.The red dashed line on the right shows the channel. the orange lines show bedding beneath the channel. Notice how it is cut by the channel. Both of these photos are of channels in alluvial fan deposits (note how coarse the rock is).