Trip M: Alleghanian deformation localized against Acadian buttress gneisses: A stretching fault, metamorphic react...

This trip in south central Connecticut examines outcrops in the high-grade portion of a transect across the Acadian metamorphic field gradient from anatexis in the west to staurolite grade in the east, with special attention to the Alleghanian overprint in the East Derby shear zone (Wintsch et al., 2024, AJS). In Seymour we show evidence for Acadian metamorphism and anatexis in Late Ordovician (buttress) orthogneisses, and in Bethany we examine weakly metamorphosed early Silurian (Pumpkin Ground) orthogneiss with Alleghanian shear zones. In Derby and Shelton we examine Early Devonian fabrics in staurolite/kyanite grade metasediments (Ague, 1994, AJS) that are overprinted and retrograded by greenschist facies Alleghanian cleavages. These fabrics converge to form the mappable East Derby shear zone that facilitated a flexural flow anticline and a stretching fault in the western Wepawaug Schist. Interpretations will be supported by geochronology and optical, BSE, and element map images presented on the outcrop.…