Characterization of the Southern Contact of the Eastern Kovik Domain Tectonic Window: Preliminary Results
Isabelle Therriault, The University of British Columbia Okanagan
Cristina Accotto, Université Laval
Kyle Larson, The University of British Columbia Okanagan
Abstract
The Ungava orogen (UO) of Nunavik, Québec, lies within the north-eastern portion of the Trans-Hudson orogen and has been interpreted as the result of a Paleoproterozoic collision between the Churchill collage upper plate and the Archean Superior Craton lower plate. Even though the UO is often cited as one of the earliest examples of a complete Wilson Cycle of opening and closing of the Manikewan Ocean, its stratigraphy and tectono-metamorphic evolution remain loosely constrained to this day. The UO is typically described as consisting of four lithotectonic domains separated by major south-verging thrust faults: the Southern, Northern, Kovik and Narsajuaq Domains. Although most of the previous studies agree on some aspects of the formation of the overall orogen, tectonic models for those individual domains are often inconsistent. Moreover, the detailed nature, timing and kinematics of the major bounding structures between those domains have not been fully explored, leaving several questions unanswered regarding the amalgamation and architecture of the UO. To help address part of this knowledge gap, geological and structural mapping and specimen collection were conducted during the summers of 2022 and 2023 across key portions of the UO in order to investigate the dominant structural features. In this study, we focus on the structural characterization of two locations along the southern contact of the eastern Kovik Domain tectonic window, the Synform and Tadpole areas, and present new in situ geochronological results. Shear sense indicators point to thrust-sense movement in the Synform area, but normal-sense movement in the Tadpole area, which was unexpected. Preliminary results of apatite dating yield U-Pb ages of ca. 1700 Ma at both locations while preliminary results of mica dating yield Rb-Sr ages of ca. 1685 Ma (biotite) and ca. 1645 Ma (white mica) in the Synform area. The results of this study will be integrated with other thematic, multi-scale investigations in various portions of the UO and will contribute to our understanding of the evolution of the orogen within the broader tectonic and kinematic framework of the Trans-Hudson orogen.
Session
Convergent and transpressional orogens