Flame structures are a type of soft-sediment deformation that forms in unconsolidated sediments. They are characterized by upward-pointing, flame-shaped tongues of finer-grained sediment that protrude into coarser-grained sediment. Flame structures are often found in turbidites, which are deposits of sediment that have been transported by currents.
Flame structures are formed when a layer of finer-grained sediment is deposited on top of a layer of coarser-grained sediment. The weight of the finer-grained sediment causes the coarser-grained sediment to compact. As the coarser-grained sediment compacts, it pushes up into the finer-grained sediment, forming the flame-shaped structures.
Flame structures can be used to interpret the depositional environment of a sediment. For example, the presence of flame structures in a turbidite indicates that the sediment was deposited by a current. The size and shape of the flame structures can also provide information about the strength of the current and the type of sediment that was being transported.
Flame structures are also important for geologists because they can be used to identify paleo-faults. A paleo-fault is a fault that was active in the past. Flame structures are often found near paleo-faults because the movement of the fault can cause the sediments to be deformed.