Marl
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For the red algal growth form, see Maerl.
Scala dei Turchi coastal marl formation, southern Sicily.
Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay and calcium carbonate, formed under freshwater conditions; specifically an earthy substance containing 35-65% clay and 65-35% carbonate.[1] It also describes a habit of coralline red alga.[2] The term is today often used to describe indurated marine deposits and lacustrine (lake) sediments which more accurately should be named marlstone. Marlstone is an indurated rock of about the same composition as marl, more correctly called an earthy or impure argillaceous limestone. It has a blocky subconchoidal fracture, and is less fissile than shale. The term marl is widely used in English-language geology, while the terms Mergel and Seekreide (German for "lake chalk") are used in European references.
Scheme of the transitional lithotypes from mud (or mudstone) to lime (or limestone), illustrating the definition of marl (marlstone) as a mix of calcium carbonate and clay.
The lower stratigraphic units of the chalk cliffs of Dover consist of a sequence of glauconitic marls followed by rhythmically-banded limestone and marl layers. Upper Cretaceous cyclic sequences in Germany and marl–opal-rich Tortonian-Messinian strata in the Sorbas basin related to multiple sea drawdown have been correlated with Milankovitch orbital forcing.[3]
Marl as lacustrine sediment is common in post-glacial lake bed sediments, often found underlying peat bogs. It has been utilized as a soil conditioner and acid soil neutralizing agent.
See also
- Agricultural lime
- Keuper marl
- Loam - which is sand and clay rather than lime and clay.
References
- ^ Sedimentary Rocks. Pettijohn, F. J., Harper& Brothers New York 1957, p. 410
- ^ Steneck, R. S. (1986). "The Ecology of Coralline Algal Crusts: Convergent Patterns and Adaptative Strategies". Annual Review of Ecology and Systematics 17: 273–303. doi:10.1146/annurev.es.17.110186.001421. JSTOR 2096997. edit
- ^ Krijgsman, W (2001). "Astrochronology for the Messinian Sorbas basin (SE Spain) and orbital (precessional) forcing for evaporite cyclicity". Sedimentary Geology 140: 43. Bibcode 2001SedG..140...43K. doi:10.1016/S0037-0738(00)00171-8.
- Schurrenberger, D., Russell, J. and Kerry Kelts. 2003. Classification of lacustrine sediments based on sedimentary components. Journal of Paleolimnology 29: 141-154.
- Chalk of Kent by C. S. Harris Accessed 11/06/2005
- Geochemistry and time-series analyses of orbitally forced Upper Cretaceous marl–limestone rhythmites, abstract Accessed 11/06/2005
- Palaeoenvironmental Interpretation of the Early Postglacial Sedimentary Record of a Marl Lake Accessed 11/06/2005
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Marl — Marl … Wikipédia en Français
Marl — Marl, v. t. [imp. & p. p. {Marled}; p. pr. & vb. n. {Marling}.] [Cf. F. marner. See {Marl}, n.] To overspread or manure with marl; as, to marl a field. [1913 Webster] … The Collaborative International Dictionary of English
marl — marl1 [märl] n. [ME < OFr marle < ML margila (> Ger mergel), dim. of L marga, marl < Gaul] 1. a mixture of clay, sand, and limestone in varying proportions, that is soft and crumbly and usually contains shell fragments 2. any loose,… … English World dictionary
marl — marl·berry; marl·bor·ough; marl·ite; marl; … English syllables
marl|y — «MAHR lee», adjective, marl|i|er, marl|i|est. of, like, or full of marl … Useful english dictionary
Marl — Marl, n. [OF. marle, F. marne, LL. margila, dim. of L. marga marl. Originally a Celtic word, according to Pliny, xvii. 7: Quod genus terr[ae] Galli et Britanni margam vocant. [root]274.] A mixed earthy substance, consisting of carbonate of lime,… … The Collaborative International Dictionary of English
Marl — Marl, v. t. [See {Marline}.] (Naut.) To cover, as part of a rope, with marline, marking a pecular hitch at each turn to prevent unwinding. [1913 Webster] {Marling spike}. (Naut.) See under {Marline}. [1913 Webster] … The Collaborative International Dictionary of English
marl — [ma:l US ma:rl] n [U] 1.) soil consisting of ↑lime and ↑clay 2.) cloth which has pale threads running through another colour ▪ a jacket available in black or grey marl … Dictionary of contemporary English
marl — clayey soil used for fertilizer, late 14c., from O.Fr. marle (Mod.Fr. marne), from L.L. marglia, dim. of L. marga marl, which is said by Pliny to be a Gaulish word, but modern Celtic cognates are considered to be borrowed from English or French.… … Etymology dictionary
marl — Ⅰ. marl [1] ► NOUN ▪ an unconsolidated sedimentary rock or soil consisting of clay and lime, formerly used as fertilizer. ORIGIN Old French marle, from Latin marga, of Celtic origin. Ⅱ. marl [2] ► NOUN ▪ a mottled yarn or fabric … English terms dictionary
Marl — Marl, so v.w. Mergel … Pierer's Universal-Lexikon