FLUTE CASTS
Flute casts are scoop-shaped structures on the soles
(undersides) of beds. They are features representing sediments that
filled depressions on the immediately subjacent bedding plane. Flute
casts form by erosive scour. The most common geologic phenomena that
produce flute casts are turbidity currents (underwater sediment slides).
Sedimentary rocks representing deposition by ancient turbidity currents are
called turbidites. Many turbidite successions have well preserved
flute casts.
Flute casts can provide current directions (=
upslope-downslope directions). The scoop-shaped end of each flute cast
points up-current (see below).
Flute casts on the sole of a mudrock (12.8 cm across at its widest). The
turbidity current that produced this moved from left to right
(>>>>>>). This sample is from a turbidite flysch
succession in an ancient foreland basin setting. Stratigraphy &
age: β3 or β4 member (sensu Enos, 1969 - Geological
Society of America Special Paper 117), Cloridorme Formation, Caradocian,
Ordovician. Locality: shoreline cliff at St. Yvon, northeastern
Gaspˇ Peninsula, northern East Gaspˇ County, Quebec, Canada.