The Origin and Significance of Sand Volcanoes in the Bude Formation (Cornwall)

Abstract

Sand volcanoes have been found in three sedimentary associations in the Upper Carboniferous Bude Formation. In two of these associations they formed when the dewatering of fluidized sand beds, deposited from traction carpets, was temporarily inhibited by the deposition of overlying units. In the third association the volcanoes formed during the normal post-depositional compaction of fluidized, muddy, poorly sorted units deposited from subaqueous mudflows. While is seems that the tops of fluidized sand beds were characteristically sheared by a fairly powerful current immediately after being deposited, the waters above the recently deposited mudflow units were commonly stagnant, a11owing sand volcano growth.

Miniature mud volcanoes and other injection features in tidal flats, James Bay, Québec

“…Although cold regions are not probably the only environment where these features could form, this environment should be considered when interpreting similar features in consolidated rocks. This cold region, tidal flats environment has not been advocated for the miniature mud or sand volcanoes and the dikes forming polygonal patterns observed in consolidated rocks (Nevi11 1957; Gill and Kuenen 1958;Warren 1963;Rust 1965;Dzulynski and Walton 1965;Oomkens 1966;Burne 1970). Most authors considered mud volcanoes as characteristic of subaqueous mudflows or slump sheets, commonly related to flysch deposits.…”

“…In consolidated rocks, mud and sand volcanoes were reported by Nevill (1957), Gill and Kuenen (1958), Oldershaw (1960), Warren (1963), Rust (1965), Burne (1970), and Walter (1972), while dikes forming polygonal patterns were reported only by Whitaker (1964) and Morrow (1972). In addition, mud and sand miniature volcanoes have been experimentally produced (Rettger 1935, p. 288;Gill and Kuenen 1958, pp.…”

“…Liquefaction may be due also to other causes: seismic shock, slumping, or dewatering by compacting and overloading (Nevi11 1957; Gill and Kuenen 1958 ;Rust 1965 ;Burne 1970). According to Rust (1965, p. 238), sudden shock is a requisite condition for the production of modern miniature sand or mud volcanoes.…”

Comments on ‘Hybrid sediment gravity flows – classification, origin and significance’ from Haughton, Davis, McCaffrey and Barker (Marine and Petroleum Geology, 2009, 26, 1900–1918)

“…Partial foundering of this sand (e.g., Talling et al, 2004) reflects the weakness of the postliquefaction substrate. In hybrid beds of the Bude Formation of SW England ("slurried beds" of Burne,1970), the sand cap (where present) was interpreted by Burne (1970) as sand volcanoes that coalesced laterally and tended to founder as load balls. The slurried beds were interpreted by Burne (1970) as mudflow deposits, whereas Higgs (1991Higgs ( , 1998 reinterpreted them as seismites, and the Bude Formation as fresh-to brackish-lake strata with rare marine bands.…”

Structures cylindriques verticales dans un dépôt meuble Quaternaire, en Galice (Espagne)

“…Les structures cylindriques sont souvent apparentées aux volcans sableux (sand volcanoes ou sand boils) des formations consolidées maintes fois décrits dans la littérature scientifique (Gill et Kuenen, 1958;Burne, 1970;Dionne, 1976). Ces formes sédimentaires résultent de la liquéfaction du sable ou du limon à la suite de séismes (Hobbs, 1907 ;Morse, 1941), à des glissements massifs sous-aquatiques ou terrestres (Nevill, 1957 ;Gill et Kuenen, 1958 ;Kojan et Hutchinson, 1978), à la surcharge (Rust, 1965) ou encore à des inondations (Holzer et Clark, 1993 ;Li et al, 1996).…”