Cobble (geology)

A conglomerate, rock made of cobbles

A cobble is a clast of rock with a particle size of 6.4 centimetres (2.5 in) to 25.6 centimetres (10.1 in) based on the Krumbein phi scale of sedimentology. Cobbles are generally considered to be larger than pebbles (4 to 64 millimetres diameter) and smaller than boulders (greater than 256 millimetres diameter). A rock made predominantly of cobbles is termed a conglomerate.^[1]

See also

• Gravel
• Particle size (grain size)

References

Coastal geography Landforms Anchialine pool Archipelago Atoll Avulsion Ayre Barrier island Bay Baymouth bar Bight Brackish marsh Cape Channel Cliff Cliff-top dune Cliffed coast Coast Coastal plain Coastal waterfall Continental margin Continental shelf Coral reef Cove Dune Estuary Firth Fjard Fjord Flat coast Freshwater marsh Fundus Gat Geo Graded shoreline Gulf Gut Headland Inlet Intertidal wetland Island Islet Isthmus Lagoon Machair Marine terrace Mega delta Mouth bar Mudflat Natural arch Peninsula Raised shoreline Reef Regressive delta Ria River delta Rocky shore Salt marsh Shoal Shore Sound Stack Steep coast Strait Strand plain Submarine canyon Tidal island Tidal marsh Tide pool Tied island Tombolo Windwatt more ... Beaches Beach cusps Beach evolution Beach morphodynamics Beach ridge Beachrock Modern recession of beaches Pocket beach Raised beach Shingle beach Storm beach Wash margin Processes Blowhole Coastal biogeomorphology Coastal erosion Concordant coastline Current Cuspate foreland Discordant coastline Emergent coastline Feeder bluff Fetch Headlands and bays Large-scale coastal behaviour Longshore drift Marine regression Marine transgression Rip current Sea cave Sea foam Shoal Spit Submergent coastline Surf break Surf zone Surge channel Swash Undertow Volcanic arc Wave-cut platform Wave shoaling Wind wave Wrack zone Management Accretion Coastal management Integrated coastal zone management Submersion Related Bulkhead line Coastline length Intertidal zone Littoral zone Grain size boulder cobble clay granule pebble sand shingle silt Physical oceanography Region of freshwater influence more ...