Ice-ridged moraines and their relation to glaciers [Montana]

Dyson, James L.

doi:10.2475/ajs.250.3.204

Cited by 44 publications

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“…These obstructions can take the form of boulders embedded in the till , or bedrock knobs. Thus, the th eory is a d eve lopment of that initially suggested by Dyson ( 1952 ), and it accounts for th e d e tailed form , th e internal structure, and the distribution of flut es on surfaces revealed from beneath re treating glaciers. I n other words, flutes are similar to many o th er "shear marks" form ed when two surfaces slid e over each other.…”

Section: J Ntrod Uctionmentioning

confidence: 62%

The Origin of Glacially Fluted Surfaces-Observations and Theory

1976

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ABSTRACT. Studies of Ruted surfaces beyond the ma rgins of glac ie rs in Spitsberge n , I ce la nd , Norwa y a nd the Alps show that almost all emanate from rigid o bstructions, commonly boulders in till. Fi eld relations of Rutes are d escribed and it is shown that a rel a tionship exists b e tween Rute h eight and the h eight of the initiating obstruction. Subglacia l observations indi ca te that Rutes form wh en till is intruded into tunnels whi ch te nd to open up in the lee of obstacles . The pattern of stra in implied by this process is shown to be reRec ted by mi cro-a nd mac rofabri cs in the till . Th e commonly found occurrence of an ave rage spacing be tween Rutes d oes not arise b ecause of some rhythmic or periodi c m echanism in the gla cie r , but is produced by the rand om seeding of b o uld ers whi ch themselves generate Autes.It is sugges ted th a t the term Rute be used a s a g en eti c ra ther tha n a d esc riptive term, and b e res tricted to long p a ra llel-sided ridges whi ch re Aec t acc urately the direction of ice m ove ment and whi ch form wh en d eformabl e subgl ac ia l m a te rials are intrud ed into tunnels whi ch te nd to open up on the lee sides of single rigid o bstruc tio ns on the glac ier bed.RES UME. L 'arigine des surfaces glaciaires "cl fiules"-abservaliall s el Ih earie. D es etud es d e surfa ces cannelees en Autes au-dela des marges d es gl ac iers au Spitsb e rg, en Island e, en N o rveg e e t dans les Alpes, montrent que d e presque toutes emergent d es obstacles solides, d 'ordin a ires d es bl ocs d a ns la moraine. La d escription d e I'en vironn em ent d es Rutes montre qu ' il existe un e rela tion entre la h a uteur d e la Rute e t la hauteur d e I'obstacl e qui en es t I' origin e. D es obse rva tions sou s-gl acia ires indiqu e nt que les Rutes se form e nt lorsque la morain e s' e ngage da ns d es tunnel s qui tendent a s' ela rgir a I' ava l d e I'obsta cle. Le typ e d e contrainte mise en j eu par ce processus es t. m o nll'e-t-on, un reRe t d e la compos ition e n p e tits et gros elements d e la morain e. La consta ti o n courante d ' un esp acement moyen e ntre les Au les ne vi ent pas d e quelque m ecanism e rythmiquc ou pe ri odiqu e d a ns le gl ac ie r , m a is es t le produit d e la repa rtiti on a lealo ire d es blocs qui o nt engendres les Rules .On suggere d 'e mpl oyer le m o t AUl e comme un term e genetiqu e plut a l que desc riptif, e l d e le reserver a d es ri des a ll o ngees a bords p a ra ll eles qui reRe tenl fid elem ent la direc ti o n du m ou veme nt d e la gl ace et qui se forment lo rsque des ma te riaux sous-glacia ires deforma bl es s'engagent d a ns d es tunn els qui l" nd ent a s'ela rgir a I' aval d' o bsta cl es so lid es indi viduels sur le lil du gl ac ier. Z USAMM EN FASSU NG . Die H erkullf l glazial gerilller Oberfiiichen -Beobachlllllgell 1I11dThearie. SI udi en a n den gerillte n OberRachen ausse rha lb d el' Gl elsch e rra ndcr in Spilzbe rge n , Island , Norwege n lmd den Alpe n zeigen , d ass a ll e an starre Hind ...

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Section: J Ntrod Uctionmentioning

confidence: 62%

The Origin of Glacially Fluted Surfaces-Observations and Theory

1976

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“…These features, occurring singly or in groups, have been found on a variety of surfaces, including lodgment till, outwash gravels, Tertiary clays, as well as on bare bedrock (Karlen, 1981;Schytt, 1963). Several hypothesis of formation have been proposed in the geologic literature (Ray, 1935;Strøm, 1963;Grant et al, 1913;Gordon et al, 1992;Lawson, 1976;Gravenor and Meneley, 1958;Paul and Evans, 1974;Morris and Morland, 1976;Boulton, 1976;Dyson, 1952;Bluemle et al, 1991;Schytt, 1963;Rose, 1989). Early work suggested flutes form either through erosion, deposition, or a combination of these processes, while more recent work emphasizes subglacial sediment deformation.…”

Section: Introductionmentioning

confidence: 89%

Analysis of flute forming conditions using ice sheet reconstructions and field techniques

Hubbard

Reid

2006

Geomorphology

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“…Also in this group are subglacial ridges (Dyson, 1952) , which are relatively long compared to their height and breadth ; subglacial ridges are usually 200 m. long by o' 5 m. high . These forms are produced by an extrusion process, in which plastic, waterlogged till beneath a glacier is squeezed up into grooves in the base of the ice.…”

Section: Drumlin Originmentioning

confidence: 99%

Drumlins and Pleistocene Ice Flow over the Ards Peninsula/Strangford Lough Area, County Down, Ireland

Vernon¹

1966

J. Glaciol.

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ABSTRACT. The geographical distribution of the drumlins was studied. They are arranged in bands perpendicular to ice pressure with a weaker alignment parallel to ice flow. An hypothesis of drumlin origin is presented. Two ice flows are present, a strong flow from an Irish centre to the north-west, and a weaker flow of Scottish ice from the north. REsuME. Drumlins et ecoulement pliistocene de la glace sur la Ards Peninsula, region de Strangford Lough, CountyDown, Ireland. On a etudie la distribution des drumlins. lis sont ranges en ban des perpendiculaires a la pression de la glace avec un alignement moins marque parallele a l'ecoulement de la glace. On peut distinguer deux courants de glace, le plus fort d'un centre irlandais vers le nord-ouest, et un courant plus faible de glace ecossaise venant du nord. ZUSAMMENFASSUNG. Drumlins und Fliessrichtung des Eises im Pleistoziin uher dem Ards

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Ice-ridged moraines and their relation to glaciers [Montana]

Cited by 44 publications

References 0 publications

The Origin of Glacially Fluted Surfaces-Observations and Theory

The Origin of Glacially Fluted Surfaces-Observations and Theory

Analysis of flute forming conditions using ice sheet reconstructions and field techniques

Drumlins and Pleistocene Ice Flow over the Ards Peninsula/Strangford Lough Area, County Down, Ireland

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