Evidence for a glacial origin of neoproterozoic III striations at Oaibaččannjar'ga, Finnmark, northern Norway
By: Rice, A.H.N.
Contributor(s): Hofmann, C.C.
Material type: ArticleDescription: 355-366pp ; Illustration.Subject(s): Evidence - Origin of glacial - Finnmark - Northern Norway | Origin - Late precambrian striated pavement - Bigganjargga - Northern Norway | Glacial formation - Northern Norway | Paleoenvironments - Northern Norway In: Geological magazine : Vol. 137 Iss. 1-6 Year. 2000Summary: Abstract The origin of the famous late Precambrian striated pavement at Oaibaččannjar'ga (Bigganjargga), northern Norway, remains controversial. Most investigators have accepted a glacial formation, but some prefer a soft-sediment mechanism. However, a newly discovered c. 2.5 mm thick zone of brecciation under rare polished striations indicates a hard substrate during formation and thus a glacial origin for the striations. Other points indicating that the striations formed in a hard substrate are: (1) the striated platform (in the Veidnesbotn Formation) is c. 150 Ma older than the overlying diamictite (Smalfjord Formation); having been buried to c. 2.5 km depth, cementation should have started before Smalfjord times; (2) the marked irregularity of the sub-Smalfjord Formation palaeotopography on Skjåholmen; (3) the presence of rounded Veidnesbotn Formation boulders in the diamictite above the striations. Imprints of clasts appearing to lie across the striations are re-interpreted as relicts of mud-flakes within the Veidnesbotn Formation which were cut across and quarried-out during pavement formation. The origin of the overlying diamictite (tillite vs. debris-flow) is not constrained by the presence of glacial striations and most probably was deposited some time after striation formation.Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Article | Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002521_71 | ||
Serials/Scientific Journal | Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002521 |
Abstract
The origin of the famous late Precambrian striated pavement at Oaibaččannjar'ga (Bigganjargga), northern Norway, remains controversial. Most investigators have accepted a glacial formation, but some prefer a soft-sediment mechanism. However, a newly discovered c. 2.5 mm thick zone of brecciation under rare polished striations indicates a hard substrate during formation and thus a glacial origin for the striations. Other points indicating that the striations formed in a hard substrate are: (1) the striated platform (in the Veidnesbotn Formation) is c. 150 Ma older than the overlying diamictite (Smalfjord Formation); having been buried to c. 2.5 km depth, cementation should have started before Smalfjord times; (2) the marked irregularity of the sub-Smalfjord Formation palaeotopography on Skjåholmen; (3) the presence of rounded Veidnesbotn Formation boulders in the diamictite above the striations. Imprints of clasts appearing to lie across the striations are re-interpreted as relicts of mud-flakes within the Veidnesbotn Formation which were cut across and quarried-out during pavement formation. The origin of the overlying diamictite (tillite vs. debris-flow) is not constrained by the presence of glacial striations and most probably was deposited some time after striation formation.
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