An interglacial on snowball Earth? Dynamic ice behaviour revealed in the Chuos Formation, Namibia

Daniel P. Le Heron*, Marie E. Busfield, Fred Kamona

*Awdur cyfatebol y gwaith hwn

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

53 Dyfyniadau (Scopus)
180 Wedi eu Llwytho i Lawr (Pure)

Crynodeb

The Sturtian is the oldest (ca 716 Ma) of three pan‐global glaciations in the Cryogenian. At Omutirapo, in northern Namibia, a 2 km wide, 400 m deep palaeovalley is filled by glaciogenic strata of the Chuos Formation, which represents the Sturtian glacial record. Sedimentary logging of an exceptionally high‐quality exposure permits detailed stratigraphic descriptions and interpretations, allowing two glacial cycles to be identified. At the base of the exposed succession, strong evidence supporting glaciation includes diamictites, ice‐rafted dropstones and intensely sheared zones of interpreted subglacial origin. These facies collectively represent ice‐proximal to ice‐rafted deposits. Upsection, dropstone‐free mudstones in the middle of the succession, and the absence of diamictites, imply sedimentation free from glacial influence. However, the reappearance of glacial deposits above indicates a phase of Sturtian glacial re‐advance. Comparison with age‐equivalent strata in South Australia, where evidence for sea‐ice free sedimentation has been established previously, suggests that a Sturtian interglacial may have been extensive, implying global‐scale waxing and waning of ice sheets during a Cryogenian glacial event.
Iaith wreiddiolSaesneg
Tudalennau (o-i)411-427
Nifer y tudalennau17
CyfnodolynSedimentology
Cyfrol60
Rhif cyhoeddi2
Dyddiad ar-lein cynnar02 Awst 2012
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 01 Chwef 2013
Cyhoeddwyd yn allanolIe

Ôl bys

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