In the earth sciences, the terms fluting and flute have very different meanings in its subdisciplines of geomorphology, glaciology, sedimentology, and speleology.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp.

Geomorphology

In geomorphology, a flute is a narrow, shallow channel that runs nearly vertically down the face of a rock surface. It is formed by the

weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement) ...

and

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

of the rock surface. Correspondingly, fluting is the erosional process by which a well-jointed coarse-grained rock, such as granite or gneiss, surface develops a set of flutes. The includes the formation of small-scale ridges and depressions by wave action.

Glaciology

''For the main article about glacial flutes, please see

Flute (glacial) Glacial flutes, also known as glacial fluting, are low, narrow, elongate, straight, parallel ridges that range between several centimeters to a few meters both in width and height. This glacial landform generally consist of glacial till, but some ...

.'' In

glaciology Glaciology (; ) is the scientific study of glaciers, or more generally ice and natural phenomena that involve ice. Glaciology is an interdisciplinary Earth science that integrates geophysics, geology, physical geography, geomorphology, c ...

, flutes are narrow, elongated, straight, parallel ridges generally consisting of

till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

, but sometimes composed of

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class o ...

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel ...

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

. Flutes typically reach a height of only a few meters or less, but some may reach heights of , and up to in length. Flutes are oriented parallel to the direction of ice movement. They are formed when boulders become lodged on the glacial till floor by basal melting and can no longer be moved by the passing glacial ice and the resulting deformation of the till bed.Bell, T., Cooper, A.K., Solheim, A., Todd, B.J., Dowdeswell, J.A., and others, 2016. ''Glossary of glaciated continental margins and related geoscience methods.'' In: Dowdeswell, J.A., Canals, M., Jakobson, M., Todd, B.J., Dowdeswell, E.K. and Hogan, K.A., eds. ''Atlas of Submarine Glacial Landforms: Modern, Quaternary and Ancient.'' Geological Society, London, Memoirs, 46, 555–574.Benn, D.I., and Evans, D.J.A., 2010. ''Glaciers and Glaciation.'' London, England, Hodder-Arnold. 816 pp. A fluted moraine, also called a fluted moraine surface, is a glacial moraine whose surface exhibits parallel ridges, glacial flutes. They are typically tens of centimeters to a few meters in width and height, and tens of meters in length. The long axes of the flutes are parallel to the flow direction of the

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

. Fluted moraines mainly developed in till surfaces on land, but some have been found in shallow glacimarine settings. Finally, in glaciology, fluting is used in older publications for smooth, deep, gutterlike channels or furrows cut by glaciers into the stoss side of a rocky hill obstructing its advance. Fluting is larger than glacial grooves and do not extend around the hill to its lee side.Chamberlin, T.C., 1888. ''The Rock-scorings of the Great Ice Invasions'', In J. W, Powell, ''7th Annual Field Report 1885-6''. United States Geological Survey, pp. 155-248.

Sedimentology

''For the main article about the sedimentary structures known as flutes and flute casts, please see

Sole markings Sole marks are sedimentary structures found on the bases of certain strata, that indicate small-scale (usually on the order of centimetres) grooves or irregularities. This usually occurs at the interface of two differing lithologies and/or gra ...

.'' In sedimentology, a flute is a primary

sedimentary structure Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition. Sediments and sedimentary rocks are characterized by bedding, which occurs when layers of sediment, with different particl ...

consisting of a discontinuous scoop-shaped, spatulate, or lingulate depression or groove. Flutes typically range from , in width, from and in depth, and from a few centimeters up to rarely in depth. They exhibit a steep or abrupt upcurrent end where their depth usually is the greatest. A flute’s long axis is typically parallel to the current. They are typically created by the scouring action of a turbulent, sediment-laden current of water flowing over a muddy bottom. The process by which a flute is formed by the cutting or scouring action of a current of water is often called fluting. After their formation, these types of flutes are often preserved by being filled by sandy or silty

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

to form flute casts, which are infrequently also called fluting.Collinson, J., and Mountney, N., 2019. ''Sedimentary Structures'', 4th ed. Dunedin, England, Academic Press Ltd. 779 pp. Crowell, J.C., 1955. ''Directional-current structures from the Prealpine Flysch, Switzerland.'' ''Geological Society of America Bulletin'', 66(11), pp.1351-1384.

Speleology

speleology Speleology is the scientific study of caves and other karst features, as well as their make-up, structure, physical properties, history, life forms, and the processes by which they form ( speleogenesis) and change over time (speleomorphology) ...

, flutes are grooves in the walls of a cave that are formed by the dissolution of

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...

rocks of cave walls by descending water. They are typically found in the walls of vertical cave shafts.

References

Landforms Glaciology Glacial landforms Sedimentary structures {{geology-stub