Origin of the Umbrella Hill Conglomerate, North-central Vermont

Badger, Robert L.

doi:10.2475/ajs.279.6.692

Cited by 2 publications

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“…In northern Vermont, the Umbrella Hill Formation consists of debris flow conglomerates found at the base of the Cram Hill Formation (Doolan and others, 1982). It contains abundant quartz vein, metasedimentary and sedimentary rock fragments (Badger, 1979;Doolan and others, 1982), and unconformably overlies previously metamorphosed and deformed rocks assigned to the Humber zone (Doolan and others, 1982). The Umbrella Hill Formation is located at the same stratigraphic position as the Saint-Daniel Mélange polymictic debris flows and both units contain abundant continent-derived clasts (Doolan and others, 1982;Schroetter and others, 2006).…”

Section: Age Provenance and Correlation Interpretationsmentioning

confidence: 98%

Taconian orogenesis, sedimentation and magmatism in the southern Quebec-northern Vermont Appalachians: Stratigraphic and detrital mineral record of Iapetan suturing

Souza

Tremblay

Ruffet

2014

American Journal of Science

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International audienceCambrian-Ordovician units of the southern Quebec Appalachians oceanic domain include obducted ophiolites and an overlying syncollisional sedimentary basin represented by the Saint-Daniel Mélange and flysch units of the Magog Group. These terrains were thrust onto the Laurentian continental margin during the Taconian orogeny and are unconformably overlain by Silurian-Devonian successor basins. This contribution presents and discusses new stratigraphic data acquired in the oceanic domain, as well as U-Pb and 40Ar/39Ar geochronological data on detrital zircons and muscovites sampled at various stratigraphic levels, from the base of the sedimentary units of the oceanic domain and the Silurian-Devonian units of the Gaspé Belt. This work, combined with the compilation of existing data for southern Quebec and western New England allows a better definition of the tectono-stratigraphic evolution of the area, and are used to propose correlations with different rock units of the northern New England Appalachians, which represents a collage of Laurentian margin and oceanic units. It is shown that Cambrian-Ordovician rocks of southern Quebec and northern Vermont have undergone a similar tectonic evolution. The ophiolites were obducted onto the Laurentian margin as a more or less coherent slab of oceanic lithosphere. Both the ophiolites and continental margin rocks were uplifted, eroded and unconformably overlain by Middle to Late Ordovician units of the Saint-Daniel Mélange and Magog Group in a forearc setting. The presence of mafic and felsic volcanic flows that are interstratified within the Saint-Daniel Mélange can be correlated with an episode of delamination and slab breakoff during the final stages of obduction and exhumation of the orogenic wedge. The Magog Group was deposited during the emplacement of the Taconian nappes, as the outboard volcanic arc was still active but progressively shutting down. The provenances suggested by the age of the dated detrital minerals can be entirely reconciled with the peri-Laurentian context of the studied rock units and testify of the tectonic evolution and sedimentary recycling of the Taconian orogen, from ophiolite obduction onto the Laurentian margin, to the collapse of the orogenic belt and the formation of successor basins

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Section: Age Provenance and Correlation Interpretationsmentioning

confidence: 98%