• Siliciclastic classification
• Major groups = texture/grain size
• Gravel = conglomerate/breccia
• Sand = sandstone
• Silt = siltstone
• Clay = mudstone
Sandstones
• Sandstones
– R. Folk, R. Dott
• Framework versus matrix
– Arenites - wackes
• Percent of framework
– Quartz, feldspar, lithics
– QFL
Sandstones - Arenites
• Quartz arenite
– Multiple cycles of reworking
• Feldspathic arenite
– Arkose
– Close to source
• Lithic arenite
– Unstable fragments
– Tectonically active areas
Sandstones - wackes
• More than 5% matrix
• Close to source
• Most common = Greywacke (lithic)
– Tectonically active area
• Feldspathic wacke
– Active/unstable deep water basins
Conglomerate/Breccia
• Gravel (>2 mm)
• Conglomerates
– Oligomict
– Polymict
• Clast versus matrix supported
• Flat pebble cgl
• Breccia
– Epiclastic
– Vocanic
– Cataclastic
– solution
Siltstone/Mudstone
• Quartz, felspar, and clay minerals
• Siltstones
• Mudstones versus shale - fissility
• Make up large percentage of sed. Record
• Not well studied