Comparative effects of tectonism on Silurian carbonate platform evolution

Conference · Wed Jan 01 00:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5878734

Soja, C M ^[1]

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1. Colgate Univ., Hamilton, NY (United States). Geology Dept.

Detailed comparisons of Silurian carbonates that formed under similar subtropical-tropical conditions in an island arc (Alexander terrane, Alaska), an orogenic belt (Oslo region, Norway), and on a stale craton (Gotland, Sweden) are used to evaluate tectonic controls on carbonate platform sedimentation. Silurian carbonates from Alaska record the evolution of a submarine platform in an island arc affected by late Silurian orogenesis. Silurian limestones that formed on the Baltoscandinavian epicontinental platform experienced Caledonian orogenesis in the Oslo region but accumulated on Gotland several 100 km east of the Caledonide front under quiescent tectonic conditions. This study shows that previous models for carbonate platform development do not predict the disproportionately thick carbonate sequences and characteristics of rocks preserved in the Alaskan island arc. High rates of subsidence and accumulation, steep submarine slopes, tectonic instability, and biogeographic isolation resulted in extraordinarily thick platform and periplatform carbonates, sequential evolution of fringing and barrier reefs, and patterns of faunal turnover that differentiate Silurian arc deposits from coeval carbonates that formed on the craton and in the orogenic belt. On the craton and in the orogenic belt, marine organisms were relatively unaffected by tectonic disturbances, but in the island arc marine biotas experienced regional extinction and faunal turnover. Similarities in the stages in carbonate platform development in the Oslo region and Alaska reflect comparable events involving compression, foreland basin evolution, and subsequent rejuvenation of carbonate depositional sites. Widespread destruction of carbonate environments correlated with orogenic activity and global marine regression eventually produced similar subaerial conditions in the Alexander terrane and across Baltoscandinavia by the late Silurian.

• OSTI ID: 5878734
• Report Number(s): CONF-921058-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
02 PETROLEUM
ALASKA
SEDIMENTARY BASINS
NORWAY
TECTONICS
SWEDEN
BIOLOGICAL EXTINCTION
CARBONATE ROCKS
COMPARATIVE EVALUATIONS
GEOLOGIC HISTORY
GEOLOGIC MODELS
OROGENESIS
SEDIMENTATION
SILURIAN PERIOD
THICKNESS
DEVELOPED COUNTRIES
DIMENSIONS
EUROPE
EVALUATION
GEOLOGIC AGES
GEOLOGIC STRUCTURES
NORTH AMERICA
PALEOZOIC ERA
ROCKS
SCANDINAVIA
SEDIMENTARY ROCKS
USA
WESTERN EUROPE
580000* - Geosciences
020200 - Petroleum- Reserves
Geology
& Exploration