Initiation and early development of the Dingle Basin, SW Ireland, in the context of the closure of the Iapetus Ocean
J. Douglas Boyd, Roderick J. Sloan, 2000. "Initiation and early development of the Dingle Basin, SW Ireland, in the context of the closure of the Iapetus Ocean", New Perspectives on the Old Red Sandstone, P. F. Friend, B. P. J. Williams
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The Dingle Basin of southwest Ireland lies within 40 km of the present-day trace of the Iapetus Suture. Its late Silurian fill (Dunquin Group and lower Dingle Group) is an important and, in many aspects, unique record of late Caledonian development in the Irish and British sector of the orogen. The upper Wenlock–upper Ludlow Dunquin Group comprises shallow-marine to non-marine siliciclastic and volcanic rocks (acid pyroclastic deposits and predominantly andesitic lavas) deposited on and around a volcanic island(s), whereas the lower, upper Ludlow–Přídolí, part of the overlying Dingle Group comprises sandstones, mudstones and minor conglomerates deposited in lacustrine, lake margin and succeeding fluvial systems. The change from marine Dunquin Group to non-marine Dingle Group (Old Red Sandstone) sedimentation is interpreted to have been tectonically driven. The succession is interpreted in terms of four phases of basin evolution: (1) a phase related to active subduction; (2) a phase related to subduction termination; (3) a post-subduction thermal subsidence phase; (4) a phase of strike-slip fault-controlled subsidence. In the broader, late-Caledonian context, the Dunquin Group volcanic rocks and associated sediments are interpreted as representing localized subduction of a final vestigial portion of Iapetus oceanic crust. The later, inferred, strike-slip influence in the basin is believed to be part of the well-documented regional strike-slip regime affecting this sector of the Caledonides.
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New Perspectives on the Old Red Sandstone
From the 1960s onwards, the Old Red Sandstone of both borders of the Atlantic Ocean has acted as a test-bed for the development of new ideas on the interpretation of fluvial, lacustrine and aeolian sedimentary rocks, and the investigation of tectonically-active basins. Much of the earlier reconnaissance work is now being reviewed in the light of further detailed field study, along with new developments in the understanding of the biostratigraphy, palaeobiology, geochronology, pedogenesis and tectonics.
Three general papers review recent work on the stratigraphical and chronological analysis of the Late Silurian, Devonian and Early Carboniferous strata, and summarize present understanding of the tectonics of the basins. These are then followed by twenty-seven contributions covering new work in Eastern USA, Canada, Ireland, Britain, Norway, Greenland and Spitsbergen.