Stratigraphy, provenance, and syn-orogenic evolution of the Gibbett Hill and Quidi Vidi formations (lower Signal Hill Group), Avalon Peninsula (Newfoundland)

• Main Author: Serna Ortiz, Santiago Alberto
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2023
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/16094/; https://research.library.mun.ca/16094/1/converted.pdf

Sedimentologic and provenance studies of the syn-orogenic Ediacaran lower Signal Hill Group (Gibbett Hill and Quidi Vidi formations) in the Avalon Peninsula, Newfoundland, Canada, were conducted to test structural and depositional models related to late Ediacaran West Avalonian orogenesis. Two facies associations corresponding to delta front and delta plain environments were identified from five stratigraphic sections. The presence of an unconformity between these facies near the location of a previously proposed thrust-related paleo-high and changes in sedimentary patterns reflecting shoreline regression supports hypothetical syn-sedimentary uplift and reveals coeval base level fall. Framework petrography, detrital geochronology, and detrital heavy mineral analysis indicate sediment sourcing from hinterlands of West Avalonian igneous and metamorphic basement. Changes in provenance were noted between the delta front and delta plain facies coeval with regression of the Signal Hill delta that suggests coeval thrusting of volcanic cover sequences over previously exhumed plutonic sources and the exhumation of higher-grade metamorphic rocks in the hinterlands. Detrital zircon U-Pb maximum depositional ages of the delta front and delta plain facies yield 557 ± 9 Ma and 556 ± 22 Ma, respectively, constraining this episode of West Avalonian hinterland exhumation, wedge-top foreland basin deformation, and forced regression to ca. 556 Ma.