Silurian Geology of Change Islands and Eastern Notre Dame Bay, Newfoundland

Eastler, Thomas E.

doi:10.1306/m12367c32

Cited by 5 publications

(1 citation statement)

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“…The stratigraphic base of the Botwood Group, outcropping from Hamilton Sound to the southern Bay of Exploits, is marked by felsic and mafic volcanic rocks extruded into a shallow marine or subaerial environment. The contact with the underlying flysch is apparently conformable, in contrast with the Notre Dame Subzone, and both clasts and matrix of interbedded red conglomerate contain Llandovery fossils that are similar to those in the flysch (Eastler 1969;H. Williams 1972).…”

Section: Exploits Subzonementioning

confidence: 97%

Parallel geological development in the Dunnage Zone of Newfoundland and the Lower Palaeozoic terranes of southern Scotland: an assessment

Colman-Sadd

Stone

Swinden³

et al. 1992

Transactions of the Royal Society of Edinburgh: Earth Sciences

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The Notre Dame and Exploits subzones of Newfoundland's Dunnage Zone are correlated with the Midland Valley and Southern Uplands of Scotland, using detailed comparisons of two key Lower Palaeozoic successions which record similar histories of extension and compression. It follows that the Baie Verte Line, Red Indian Line and Dover Fault are equivalent to the Highland Boundary Fault, Southern Upland Fault and Solway Line, respectively.The Betts Cove Complex and overlying Snooks Arm Group of the Notre Dame Subzone are analogous to the Ballantrae Complex of the Midland Valley, both recording the Arenig evolution and subsequent obduction of an arc and back-arc system. The Early Ordovician to Silurian sequence unconformably overlying the Ballantrae Complex is poorly represented in the Notre Dame Subzone but important similarities can still be detected suggesting corresponding histories of continental margin subsidence and marine transgression.In the Exploits Subzone, Early Ordovician back-arc volcanic rocks are overlain by Llandeilo mudstones and Late Ordovician to Early Silurian turbidites. A similar stratigraphy occurs in the Northern and Central Belts of the Southern Uplands and both areas have matching transpressive structural histories. Deeper erosion in the Exploits Subzone reveals Cambrian and Early Ordovician volcano-sedimentary sequences structurally emplaced on the Gander Zone, and such rocks are probably present beneath the Southern Uplands. Combined data from the Notre Dame Subzone and Midland Valley suggest an Arenig southeast-dipping subduction zone. Early Ordovician volcanic rocks in the Exploits Subzone and Southern Uplands have back-arc basin geochemistry and support the model of the Southern Uplands as a transition from back-arc to foreland basin. Preferential emergence of the Dunnage Zone and contrasts between Exploits Subzone and Southern Uplands turbidite basins are attributed to collision of Newfoundland with a Laurentian promontory and Scotland with a re-entrant. This hypothesis also explains the transpressive structural regime common to both areas.

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Section: Exploits Subzonementioning

confidence: 97%

Parallel geological development in the Dunnage Zone of Newfoundland and the Lower Palaeozoic terranes of southern Scotland: an assessment

Colman-Sadd

Stone

Swinden³

et al. 1992

Transactions of the Royal Society of Edinburgh: Earth Sciences

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A geotraverse through the Appalachians of northern Newfoundland

1983

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The petrology of the Tilting Harbour igneous complex, Fogo Island, Newfoundland

Cawthorn¹

1978

Can. J. Earth Sci.

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The Tilting Harbour complex, Fogo Island, Newfoundland, displays a mineralogical range from olivine-bearing pyroxenites to diorites. The engulfing granite is not genetically related to the complex. On field, petrographic and chemical evidence the complex can be divided into two distinct series. The older magma is of quartz tholeiite composition with an Mg/(Mg + Fe) ratio consistent with derivation directly from the mantle by melting under fairly low pressure (10 kbar (10 × 105 kPa)) under hydrous conditions. The second magma is of olivine tholeiite composition and produced magnetite-rich gabbros. It is not a primary melt from the mantle. Subsequent differentiation produced a range of liquids from olivine-normative to silica-rich, which is best explained by hornblende fractionation. Both magma series gave rise to websterite cumulates. However, the removal of pyroxene did not produce a significant change in residual liquid composition. The Ni content of the quartz-tholeiite magma is 75 ppm and suggests a partition coefficient of about 40 between mantle olivine and the liquid. The pyroxenes that crystallized from both liquids contained five times the Ni content of the magma. The partition coefficients for Ni and Cr between hornblende and liquid, determined from the chemical variation of the magnetite-rich gabbro suite, are both approximately 2.The contamination of the granite by melting of microdiorite was selective, only the fusible constituents being assimilated while refractory components were not incorporated.

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Silurian Geology of Change Islands and Eastern Notre Dame Bay, Newfoundland

Cited by 5 publications

References 0 publications

Parallel geological development in the Dunnage Zone of Newfoundland and the Lower Palaeozoic terranes of southern Scotland: an assessment

Parallel geological development in the Dunnage Zone of Newfoundland and the Lower Palaeozoic terranes of southern Scotland: an assessment

A geotraverse through the Appalachians of northern Newfoundland

The petrology of the Tilting Harbour igneous complex, Fogo Island, Newfoundland

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