Clastic sediment consisting of less than 30 percent gravel-size (2 mm) particles and
with a mud-size to sand-size particle ratio greater than 1. More than half of the
particles are of epiclastic origin.
definition of mud from SLTTs 2004 muddy sediment; particle sizes defined from Krumbein
phi scale (W C Krumbein and L L Sloss, Stratigraphy and Sedimentation, 2nd edition,
Freeman, San Francisco, 1963; Krumbein and Pettijohn, 1938, Manual of Sedimentary
Petrography: New York, Appleton Century Co., Inc.)