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Early Paleozoic rifting and reactivation of a passive-margin rift: Insights from detrital zircon provenance signatures of the Potsdam Group, Ottawa graben

2018; Geological Society of America; Volume: 130; Issue: 7-8 Linguagem: Inglês

10.1130/b31749.1

1943-2674

David G. Lowe, R. W. C. Arnott, Jeffrey R. Chiarenzelli, R H Rainbird,

Geochemistry and Geologic Mapping

Research Article| February 27, 2018 Early Paleozoic rifting and reactivation of a passive-margin rift: Insights from detrital zircon provenance signatures of the Potsdam Group, Ottawa graben David G. Lowe; David G. Lowe † 1Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada †daveglowe25@gmail.com Search for other works by this author on: GSW Google Scholar R.W.C. Arnott; R.W.C. Arnott 1Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada Search for other works by this author on: GSW Google Scholar Jeffrey R. Chiarenzelli; Jeffrey R. Chiarenzelli 2Department of Geology, St. Lawrence University, Canton, New York 13617, USA Search for other works by this author on: GSW Google Scholar Robert H. Rainbird Robert H. Rainbird 3Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar GSA Bulletin (2018) 130 (7-8): 1377–1396. https://doi.org/10.1130/B31749.1 Article history received: 17 Jan 2017 rev-recd: 22 Oct 2017 accepted: 18 Jan 2018 first online: 27 Feb 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation David G. Lowe, R.W.C. Arnott, Jeffrey R. Chiarenzelli, Robert H. Rainbird; Early Paleozoic rifting and reactivation of a passive-margin rift: Insights from detrital zircon provenance signatures of the Potsdam Group, Ottawa graben. GSA Bulletin 2018;; 130 (7-8): 1377–1396. doi: https://doi.org/10.1130/B31749.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Ottawa graben is a Neoproterozoic intracratonic rift in northeastern North America that was reactivated throughout the Phanerozoic and persists as a modern seismically active zone of lithospheric weakness with extant topography. U-Pb geochronology of detrital zircon grains, paleoflow directions, and stratigraphic data from the Potsdam Group provide evidence of early Paleozoic rifting and reactivation of the passive-margin Ottawa graben. Early to middle Cambrian rifting (ca. 515–505 Ma) coincided with the opening of fault-bounded subbasins that were filled with arkose derived from local rift shoulders consisting mainly of ca. 1176 Ma Grenville sources from the Frontenac terrane. Additionally, the local presence of ca. 1442 Ma zircon grains suggests extensive opening of the Ottawa graben along the modern Ottawa River Valley, which provided a localized conduit for transport of sediment sourced from parts of the Central Gneiss belt, ∼350–400 km to the west. Early to middle Cambrian rifting of the Ottawa graben coincided with evidence of more widespread rifting across the Laurentian margin, suggesting that the Laurentian passive-margin rift-to-drift transition did not occur until the middle Cambrian. Later, late middle to early late Cambrian reactivation of the Ottawa graben resulted in topographic inversion marked by uplift of the adjacent Adirondack Dome, and radial dispersal of sediment with introduction of ca. 1060–1000 Ma detrital zircon grains throughout the Ottawa graben. A second episode of reactivation and topographic inversion occurred during the earliest Ordovician, marked by subsidence of the Adirondack Dome and uplift of parts of the northern Ottawa graben. This resulted in southeastward drainage and the reintroduction of ca. 1442 Ma zircon grains via reworking of older Potsdam strata and/or direct sourcing from parts of the Central Gneiss belt to the west. These two enigmatic, passive-margin early Paleozoic reactivations are correlated with events along the Laurentian margin, for example, early Furongian shelf erosion, especially near the Saguenay graben, and they are linked to perturbations in the intraplate stress field driven by plate-boundary forces originating from the peri-Laurentian and Iapetan regions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.