- Rock flour
Rock flour, or glacial flour, consists of clay-sized particles of rock, generated by glacial erosion or by artificial grinding to a similar size. Because the material is very small, it is suspended in
riverwater making the water appear cloudy. If the river flows into a glacial lake, the lakemay appear turquoise in coloras a result. Examples of this are Lake Louise and Peyto Lakein Canadaand Gjendelake in Norway.
Natural rock flour is typically formed during glacial migration, where the
glaciergrinds against rock beneath it, but is also produced by freeze thaw, where the act of water freezingand expanding in cracks helps break up rock formations.
Although clay-sized, its particles are not
clay mineralsbut typically ground up quartzand feldspar. Rock flour is carried out from the system via meltwaterstreams, where the particles travel in suspension. Rock flour particles can travel great distances either suspended in water or by the wind, in the latter case forming deposits called loess.
Some agronomists believe that rock flour has a powerful effect in restoring trace minerals to
soil. An early experimeter was the German miller Julius Hensel, author of "Bread from Stones", who reported successful results with "steinmehl" (stonemeal) in the 1890s. His ideas were not taken up through technical limitations and, according to proponents of his method, opposition from the champions of conventional fertilisers. John D. Hamakerargues that widespread remineralizationof soils with rock dust is required to reverse soil depletion by current agriculture and forestry practice.
While this was originally an alternative concept, increasing mainstream research has been devoted to
soil amendmentand other benefits of rock flour application: for instance, a pilot project on the use of glacial rock, graniteand basaltic fines by the U.S. Department of Agricultureat the Henry A. Wallace Beltsville Agricultural Research Center. The [http://www.seercentre.org.uk SEER Centre] in Scotland is a leading source of information on the use of rock dusts and mineral fines. The [http://www.reminforum.org.uk Soil Remineralization Forum] was established with sponsorship from the [http://www.sepa.org.uk Scottish Environment Protection Agency] and has commissioned a portfolio of research into the benefits of using mineral fines. The Forum provides an interface between research, environmentalists and industry.
* [http://www.gardening-guy.com/stories/storyReader$37 On a Fad Diet of Rock Dust, How the Garden Does Grow] Henry Homeyer, June 24, 2004, "New York Times".
* [http://www.remineralize.org/ Remineralize the Earth] - "non-profit organization incorporated to disseminate ideas and practice about soil remineralization".
* [http://www.championtrees.org/topsoil/PitnQuarry.htm Soil remineralization: a future market for aggregate industry fines] , Robert J. Able, June 1995, "Pit & Quarry".
* [http://www.championtrees.org/topsoil/bread.htm Julius Hensel]
* [http://www.activecompost.com/Co-utilization%20of%20Rockdust,%20Mineral%20Fines%20and%20Compost.pdf] Downloadable document on co-utilisation of mineral fines and composts
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Look at other dictionaries:
rock flour — noun : finely powdered rock material produced by grinding action (as of a glacier on its bed) called also glacial meal * * * rock flour noun Finely divided rock material, such as is found under glaciers • • • Main Entry: ↑rock * * * rock flour … Useful english dictionary
rock flour — noun finely powdered rock formed by glacial or other erosion … English new terms dictionary
rock flour — /ˈrɒk flaʊə/ (say rok flowuh) noun fine particles of rock generated by glacial erosion or artificial grinding; glacial meal … Australian English dictionary
rock flour. — See glacial meal. [1880 85] * * * … Universalium
rock flour. — See glacial meal. [1880 85] … Useful english dictionary
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