Regional stratigraphy, structural geology, and 2D seismic interpretation of auriferous terrain in the vicinity of the Appleton Fault Zone and Dog Bay Line, northeast-central Newfoundland Appalachians: post-Silurian overprint on extended crust

Northeast-central Newfoundland occupies a critical position in the northern Appalachians for understanding linkages between Silurian and Devonian tectonism and gold mineralization. West of the Gander River Complex, several fault zones transect auriferous terrain that is dominated by clastic sedimentary rocks and associated gabbroic intrusions. Silurian to Devonian fault reactivation and polydeformation, coupled with poor exposure, complicate the stratigraphy and structural history of the terrain. Systematic examination of regional outcrops and drill core, including new trench exposures on gold exploration properties, revealed the following clastic sedimentary rock successions across the area, from oldest to youngest: Early to Middle Ordovician turbiditic rocks; Sandbian to Katian black shale; Late Ordovician to Silurian non-micaceous pebbly wacke; and Silurian to Early Devonian micaceous siltstone, sandstone, and pebbly wacke. The overall architecture of the belt resembles a structurally reactivated detachment fault system with opposingly dipping faults that trace horsts, grabens, and half-grabens. The structural history of the area is characterized by three main phases of Devonian deformation involving coaxial to locally non-coaxial compression (Acadian orogeny), orogenic collapse (post-Acadian orogeny), and late dextral transpression (younger orogeny), all of which overprint an inferred (from stratigraphic correlations and 2D seismic line) Wenlock to early Lochkovian extension event. Earlier Salinic closure of the Iapetus Ocean is not recorded across the study area.