Editing Dune (section)

====Draas====
[[File:350m Düne Deadvlei Sossusvlei.JPG|thumb|Dune Nine in [[Sossusvlei]], Namibia, is over 300m high.]]
Draas are very large-scale dune bedforms; they may be tens or a few hundreds of metres in height, kilometres wide, and hundreds of kilometres in length.<ref name=Mangimeli>{{cite web| publisher = U.S.A. National Park Service| last = Mangimeli| first = John| title = Geology of Sand Dunes| date = 10 September 2007 |url=https://home.nps.gov/whsa/learn/nature/loader.cfm?csModule=security/getfile&PageID=2033934 |access-date=15 January 2021}}</ref> After a draa has reached a certain size, it generally develops superimposed dune forms.<ref name=Lancaster>{{cite journal|title=The development of large aeolian bedforms|first=N.|last=Lancaster|date=1 March 1988|journal=Sedimentary Geology|volume=55|issue=1–2|pages=69–89|doi=10.1016/0037-0738(88)90090-5|bibcode=1988SedG...55...69L}}</ref> They are thought to be more ancient and slower-moving than smaller dunes,<ref name=Mangimeli/> and to form by vertical growth of existing dunes. Draas are widespread in sand seas and are [[Cross-bedding|well-represented in the geological record]].<ref name=Lancaster/>