Moraines are unique ridges or mounds of debris that space laid down straight by a glacier or moved up by it1. The ax moraine is used to describe a wide variety of landforms created by the dumping, pushing, and also squeezing of loosened rock material, as well as the melt of glacial ice.


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Moraine ridges top top the forefield that the Matanuska Glacier, Alaska. Photo: open minded K.

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In terms of size and also shape, moraines are incredibly varied. They variety from low-relief ridges the ~1 m high and ~1 m vast formed at the snout of proactively retreating valley glaciers2, to large ‘till plains’ left behind by former continental ice cream sheets3.


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Low-relief moraine ridges on the forefield that the actively retreating Skaftafellsjökull Glacier in Iceland. The moraines mark previous ice extent and also mirror the shape of the glacier terminus at the time of formation. Photo: TommyBee

Moraines consists of loose sediment and also rock debris deposited by glacier ice, recognized as till. They may also contain slope, fluvial, lake and also marine sediments if such material is existing at the glacier margin, whereby it may be included into glacial ice during a glacier advance, or deformed by glacier movement4,5.


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Moraine composed of loosened rock and also sediment developing at the lateral margin of the Boulder Glacier, Washington, USA. Photo: W. Siegmund.

Moraines are essential features for expertise past environments. Terminal moraines, for example, note the maximum degree of a glacier advancement (see chart below) and also are provided by glaciologists to reconstruct the former size of glaciers and also ice sheets that have actually now shrunk or disappeared entirely6.


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Summary of the main moraine types and your spatial patterns. The optimal diagram is a cross-section through a cirque glacier. The bottom chart is drawn in plan view, looking under on the surface ar of a sink glacier comprised of number of tributaries. Image produced by J. Bendle.

Definitions

The most common moraine varieties are characterized below:

A terminal moraine is a moraine ridge that marks the maximum border of a glacier advance. They type at the glacier terminus and mirror the form of the ice cream margin at the moment of deposition. The largest terminal moraines are developed by significant continental ice cream sheets and can be over 100 m in height and 10s of kilometre long7,8.


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Terminal moraine noting the limit of the former Patagonian ice cream Sheet at the last Glacial preferably (~25 to 18 thousand year ago). Photo: J. Bendle.

Recessional moraines are discovered behind a terminal moraine border and type during short-lived phases the glacier breakthrough or stillstand that interrupt a general pattern the glacier retreat. In some cases, recessional moraines kind on a yearly communication (normally as a result of winter glacier advances) and are recognized as annual moraines9,10,11.


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Recessional moraines (arrowed) noting the shrinkage of a south American sink glacier. The glacier (not shown) retreated in the direction of the south-west, leaving behind a moraine-dammed glacial lake. Imagery native GoogleEarth, diagram created by J. Bendle.

Lateral moraines form follow me the glacier side and also consist that debris that falls or slumps from the valley wall surface or flows directly from the glacier surface12 (see picture below). Whereby the rate of debris it is provided is high, lateral moraines can reach heights of an ext than 100 metres12–15.


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Lateral moraine the the Callequeo Glacier that the san Lorenzo Icefield in main Patagonia, southern America. Photo: J. Martin.

The hatchet latero-frontal moraine is provided where debris builds up about the whole glacier tongue14. This moraine types are typical in mountain settings such as the europe Alps, the southern Alps of brand-new Zeland (see the Mueller Glacier moraines below) and the Himalayas, whereby the high it is provided of absent debris from rough valley sides, rapidly develop up at the glacier margins.


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Latero-frontal moraine facility of the Mueller Glacier, southern Island, new Zealand. The debris-covered and also downwasting Mueller Glacier is flanked by lateral moraines that ~100 m in height, which proceed down valley and also merge into terminal moraines. Imagery from GoogleEarth, diagram created by J. Bendle.

Medial moraines are debris ridges in ~ the glacier surface running parallel to the direction of ice flow4,5. They room the surface ar (or supraglacial) expression of debris consisted of within the ice. Medial moraines type where lateral moraines fulfill at the confluence of two valley glaciers, or wherein debris consisted of in the ice is exposed at the surface because of melting in the ablation zone16.


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Medial moraines ~ above the surface of an Alaskan valley glacier. In this example, surface debris is concentrated at the point where two glaciers merge. Imagery from GoogleEarth, diagram produced by J. Bendle.

Ground moraine is a term used to describe the uneven blanket of till deposited in the low-relief areas between more prominent moraine ridges6. This form of moraine, i beg your pardon is likewise commonly referred to as a till plain, type at the glacier single as due to the deformation and also eventual deposition the the substratum.


1. Hambrey,M. J. 1994. Glacial Environments. UCLPress.

2. Krüger,J., Schomacker, A. And also Benediktsson, Í.Ö., 2010. 6 Ice-Marginal Environments:Geomorphic and also Structural Genesis of Marginal Moraines at Mýrdalsjökull.Developmentsin Quaternary Sciences,13, 79-104.

3. Dyke,A.S. And Prest, V.K. 1987. Late Wisconsinan and Holocene history of theLaurentide ice Sheet. Geographie Physiqueet Quaternaire XLI, 237–63.

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5. Bennett,M.M. And Glasser, N.F. 2011.Glacial Geology: ice Sheets and Landforms.John Wiley & Sons.

6.Schomacker, A. 2011. Moraine (Eds.)Singh, V.P., Singh, P. And also Haritashya, U.K. Encyclopediaof Snow, Ice and Glaciers. Springer.

7. Dyke,A.S., Andrews, J.T., Clark, P.U., England, J.H., Miller, G.H., Shaw, J. AndVeillette, J.J., 2002. The Laurentide and also Innuitian ice cream sheets during the lastglacial maximum.Quaternary science Reviews,21, 9-31.

8. Glasser,N.F., Jansson, K.N., Harrison, S. And also Kleman, J., 2008. The glacialgeomorphology and Pleistocene history of southern America in between 38°S and also 56°S.QuaternaryScience Reviews,27, 365-390.

9. Sharp,M., 1984. Annual moraine ridges in ~ Skálafellsjökull, south-east Iceland.Journalof Glaciology,30, 82-93.

10. Bradwell,T., 2004. Yearly moraines and also summer temperature at Lambatungnajökull,Iceland.Arctic, Antarctic, and Alpine Research,36,502-508.

11. Beedle,M.J., Menounos, B., Luckman, B.H. And also Wheate, R., 2009. Yearly push moraines asclimate proxy.Geophysical study Letters,36.

12. Lukas,S., Graf, A., Coray, S. And also Schlüchter, C., 2012. Genesis, security andpreservation potential of big lateral moraines the Alpine valleyglaciers–towards a unifying theory based upon Findelengletscher,Switzerland.Quaternary scientific research Reviews,38, 27-48.

13. Benn,D.I. And also Owen, L.A., 2002. Himalayan glacial sedimentary environments: aframework because that reconstructing and also dating the former level of glaciers in highmountains.Quaternary International,97, 3-25.

14. Benn,D.I., Kirkbride, M.P., Owen L.A. And Brazier, V. 2003. Glaciated sink Landsystems (Ed.) Glacial Landsystems, Arnold,London.

15. Evans,D.J., Shulmeister, J. And Hyatt, O., 2010. Sedimentology that latero-frontalmoraines and fans top top the west coastline of southern Island, new Zealand.QuaternaryScience Reviews,29, 3790-3811.

16. Eyles, N. And Rogerson, R.J., 1978. A structure for the investigation of medial moraine formation: Austerdalsbreen, Norway, and Berendon Glacier, brothers Columbia, Canada.

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Journal that Glaciology,20, 99-113.