A model for northern Vermont's Acadian magmatism with insight from Italy's Tuscan magmatic province

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5639753

Westerman, D S ^[1]

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1. Norwich Univ., Northfield, VT (United States). Dept. of Geology

S-type Devonian acidic intrusives in northern Vermont occur scattered throughout the turbiditic flysch sequence and pervasive horizon of mafic Standing Pond Volcanics of the Connecticut Valley--Gaspe Trough (CVGT). These granitoids formed in a successor basin that opened over the stalled Taconic subduction zone located between the Bronson Hill--Boundary Mountain Volcanic arc (east) and the ophiolite-bearing accretionary complex of the Green Mountains (west). Contact aureoles surrounding the granitoids are superimposed over low-pressure facies series metamorphic isograds that have concentric pattern correlated with the centers of intrusion. Italy's Tuscan Magmatic Province, also dominated by S-type acidic intrusives, developed between 7 and 2 Ma in a successor basin over an extinct subduction zone. In that case, the basin and its plutons developed when the Corsica-Sardinia plate pulled back to form the Tyrrhenian Sea after having collided with Italy to form the Apennine range approximately 10 m.y. earlier. In this model for northern Vermont, a volcanic arc and accretionary complex developed during Ordovician subduction, perhaps with continuing trench--arc separation due to shallow subduction. When the leading edge of continental North America entered the subduction zone, the process stalled and the subducted Iapetus slab continued to lose heat and increase density, promoting its separation from the overlying plate. Upwelling under the former forearc region rifted the crust to form the CVGT. The mantle-derived mafic melts rose, transferring heat to metamorphose and partially melt the basin fill. The Standing Pond Volcanics represent this melt that reached the surface at one stage and flooded the basin. Northern Vermont's granitoids rose, penetrating the domed strata above their source region, as extensional tectonism was replaced by Acadian compression.

• OSTI ID: 5639753
• Report Number(s): CONF-9303211--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
DEVELOPED COUNTRIES
DEVONIAN PERIOD
EUROPE
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
IGNEOUS ROCKS
ITALY
MAGMATISM
NORTH AMERICA
PALEOZOIC ERA
PETROGENESIS
PETROLOGY
PLATE TECTONICS
PLUTONIC ROCKS
RIFT ZONES
ROCKS
SUBDUCTION ZONES
TECTONICS
USA
VERMONT
WESTERN EUROPE