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

Abstract

<jats:title>Résumé</jats:title><jats:p>Cette note signale pour la première fois l'existence de structures cylindriques verticales dans un dépôt quaternaire, en Espagne. Les deux structures observées se trouvent dans un dépôt limonosableux dans une vallée près de la frontière entre la Galice et la Castille-León, au NO de la péninsule ibérique. La structure principale mesure plus de 225 cm de hauteur, 15 cm de largeur à la base, 20-25 cm à la partie centrale et une quarantaine de centimètres au sommet. Le tiers inférieur est essentiellement sableux et caractérisé par des couches circulaires. La section centrale comprend deux cônes superposés et partiellement emboîtés, remplis de petit gravier sableux, alors que le tiers supérieur de la structure verticale, qui pénètre dans un dépôt de rudites, est essentiellement grossier. Les deux structures cylindriques verticales sont attribuées à des sources ascendantes créées par la pression hydrologique dans le dépôt glacio-lacustre lors de la mise en place de la nappe alluviale d'origine fluvio-glaciaire. Les structures sont vraisemblablement contemporaines de la formation de la nappe alluviale.</jats:p>

Grain coatings: Diagenesis of Jurassic sandstones in south-central Utah and implications for targeting fossil microbes on Mars

“…High pressures may have been caused by overburden pressure, perhaps amplified or triggered by seismic vibrations associated with faulting, volcanism, or meteoric impact (Jones, 1972;Horowitz, 1982;Glennie and Bullar, 1983;Allen, 1986;Alvarez et al, 1998;Galli, 2000). Although evidence for slurry injection from above exists, the most common interpretation is injection of hot fluids from below by ascending springs (Dionne and Perez Alberti, 2000) or in situ fluidization of the entire host rock (Netoff, 2002).…”

“…Various pipe forms are termed clastic plugs, collapse plug pipes, sandstone cylinders, sandstone plugged pipes, sandstone pipes, silica plugs, pipe-like slump structures, type B pillars, fluid escape structures, clastic pipes, sedimentary pipes, sand cylinders, dewatering pipes, sand pipes, breccia pipes, tubular fluidization pipes, injection structures, escape burrows, and sand volcano vents (summaries are in Hunter et al, 1992;Dionne and Perez Alberti, 2000;Chan et al, 2007). Deformation of these structures ranges from brittle fracture, producing small-scale faults and joints, and hydroplastic deformation (sagged and contorted beds), to liquified and fluidized bodies (without primary sedimentary structure).…”

“…Cylindrical pipes, which cut enclosing stratified host rock to great depths, mark the injection of water and/or sand slurries from below by over-pressurized water or gasses (Gableman, 1955;Phoenix, 1958;Allen, 1961;Schlee, 1963;Megrue and Kerr, 1965;Lowe, 1975;Hannum, 1980;Guhman and Pederson, 1992;Collinson, 1994;Baer and Steed, 2000;Dionne and Perez Alberti, 2000). High pressures may have been caused by overburden pressure, perhaps amplified or triggered by seismic vibrations associated with faulting, volcanism, or meteoric impact (Jones, 1972;Horowitz, 1982;Glennie and Bullar, 1983;Allen, 1986;Alvarez et al, 1998;Galli, 2000).…”

Horizontal Cylindrical Structures in an Unconsolidated Quaternary Deposit at Saint-Joachim, Near Québec City (Canada)

“…Besides, similar structures occurring in Quaternary unconsolidated deposits have been reported only thirty years ago (Dionne and Laverdière, 1972;Dionne, 1973;Dionne and Gangloff, 1975;Gangloff, 1974;Curran and Frey, 1975) and more recently by Jensen and Miller (1990) and by Dionne and Pérez Alberti (2000). Despite their uniqueness, these structures are not illustrated in most current manuals and atlas of sedimentary structures (Gubler, 1966;Conybeare and Crook, 1968;Picard and High, 1973;Collinson and Thompson, 1982;Allen, 1984;Ricci Lucchi, 1995).…”

Subaqueous artesian springs and associated spring pits in a Himalayan pond

“…Vertical, cylindrical structures in sandstone have commonly been attributed to upwelling of ground water (e.g. Hawley & Hart 1934;Gabelman 1955;Dionne 1973a;Gangloff 1974;Deynoux et al 1990;Dionne & Pérez Alberti 2000;Massari et al 2001;Kaleris et al 2002), although their occurrence together with spring pits has only recently been demonstrated (Draganits et al in press). Guhman & Pederson (1992) suggest cylindrical fluidization pipes up to 10 m in diameter and up to 44 m in depth below active boiling sand springs in Nebraska, whilst Christiansen et al (1982) and Bluemle (1993) described a vertical fluidization pipe, some 50 m in diameter and at least 138 m deep, below the circular Lake Howe in Saskatchewan.…”