Editing Scree (section)

{{Short description|Broken rock fragments at base of cliff}}
[[File:Yamnuska bottom cliff.jpg|thumb|right|upright|Talus at the bottom of [[Mount Yamnuska]], [[Alberta]], [[Canada]]]]

'''Scree''' is a collection of broken [[Rock (geology) |rock]] fragments at the base of a [[cliff]] or other steep rocky mass that has accumulated through periodic [[rockfall]]. Landforms associated with these materials are often called '''talus deposits'''.

The term ''scree'' is applied both to an unstable steep mountain slope composed of rock fragments and other [[debris]], and to the mixture of rock fragments and debris itself.<ref>{{oed|scree}}</ref><ref name=Jackson1997>{{cite book |editor-last= Jackson |editor-first= Julia A. |chapter= scree |title= Glossary of geology |date=1997 |publisher=[[American Geological Institute]] |edition= 4th |location= Alexandria, Virginia |isbn= 0922152349}}</ref><ref name=Allaby2013>{{cite book |last= Allaby |first= Michael |chapter= scree |title= A dictionary of geology and earth sciences |year= 2013 |publisher=[[Oxford University Press]] |edition= 4th |isbn= 9780199653065}}</ref> It is loosely synonymous with '''talus''', material that accumulates at the base of a projecting mass of rock,<ref name=Jackson1997/>{{sfn|Jackson|1997|loc="talus"}} or '''talus slope''', a landform composed of talus.<ref name=Thornbury66>{{cite book |last1=Thornbury |first1=William D. |title=Principles of geomorphology |date=1969 |publisher=Wiley |location=New York |isbn=0471861979 |edition=2d |page=66}}</ref> The term ''scree'' is sometimes used more broadly for any sheet of loose rock fragments mantling a slope, while ''talus'' is used more narrowly for material that accumulates at the base of a [[cliff]] or other rocky slope from which it has obviously eroded.<ref name=Jackson1997/>

Scree is formed by rockfall,<ref name=Allaby2013/><ref name=BlattEtal1980_176>{{cite book |last1=Blatt |first1=Harvey |last2=Middleton |first2=Gerard |last3=Murray |first3=Raymond |title=Origin of sedimentary rocks |date=1980 |publisher=Prentice-Hall |location=Englewood Cliffs, N.J. |isbn=0136427103 |edition=2d |page=176}}</ref> which distinguishes it from '''[[colluvium]]'''. Colluvium is rock fragments or soil deposited by [[rainwash]], [[sheetwash]], or slow [[downhill creep]], usually at the base of gentle slopes or hillsides.{{sfn|Jackson|1997|loc="colluvium"}} However, the terms ''scree'', ''talus'',<ref name=Jackson1997/><ref name=Allaby2013/> and sometimes ''colluvium''<ref name=TurnerSchuster1996/> tend to be used interchangeably. The term ''talus deposit'' is sometimes used to distinguish the landform from the material of which it is made.<ref>{{cite journal |last1=Brody |first1=A. G. |last2=Pluhar |first2=C. J. |last3=Stock |first3=G. M. |last4=Greenwood |first4=W. J. |title=Near-Surface Geophysical Imaging of a Talus Deposit in Yosemite Valley, California |journal=Environmental & Engineering Geoscience |date=1 May 2015 |volume=21 |issue=2 |pages=111–127 |doi=10.2113/gseegeosci.21.2.111|bibcode=2015EEGeo..21..111B }}</ref> The exact definition of scree in the [[primary literature]] is somewhat relaxed, and it often overlaps with both ''talus'' and ''colluvium''.<ref name=TurnerSchuster1996>{{Cite book |author= Turner, A. Keith |author2= Schuster, Robert L. |title= Landslides: investigation and mitigation |date= 1996 |publisher= National Academy Press |location= Washington, D.C. |isbn=0-309-06208-X |oclc= 33102185 |url=https://www.worldcat.org/oclc/33102185}}</ref>