GEOSCAN Search Results: Fastlink

GEOSCAN Menu


TitleZircon provenance data record the lateral extent of pancontinental, early Neoproterozoic rivers and erosional unroofing history of the Grenville orogen
AuthorRainbird, R H; Rayner, N M; Hadlari, T; Heaman, L M; Ielpi, A; Turner, E C; MacNaughton, R B
SourceGeological Society of America Bulletin 2017 p. 1-16, https://doi.org/10.1130/b31695.1
Year2017
Alt SeriesEarth Sciences Sector, Contribution Series 20160172
PublisherGeological Society of America
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceNorthwest Territories; Yukon
NTS77; 87; 88; 86I; 86J; 86K; 86L; 86M; 86N; 86O; 86P; 96I; 96J; 96K; 96L; 96M; 96N; 96O; 96P; 97; 106; 107
AreaMackenzie Basin; Victoria Island
Lat/Long WENS-136.0000 -108.0000 74.0000 64.0000
Subjectsgeochronology; stratigraphy; sedimentology; uranium lead dates; uranium lead dating; radiometric dating; sedimentary rocks; sandstones; mass spectrometer analysis; provenance; orogenesis; Minto Inlier; Brock Inlier; Grenville Orogen; Mackenzie Mountains Supergroup; Shaler Supergroup; Rae Group; Katherine Group; Tsezotene Formation; Escape Rapids Formation; Nelson Head Formation; Mackenzie Mountains Supergroup; Precambrian; Proterozoic
Illustrationslocation maps; stratigraphic columns; diagrams; stratigraphic correlations
ProgramMackenzie Corridor, Shield to Selwyn, GEM2: Geo-mapping for Energy and Minerals
AbstractWe present detrital zircon U-Pb data from mainly fluvial sandstones of the Mackenzie Mountains Supergroup, Yukon (four samples), and the Shaler Supergroup, Northwest Territories (seven samples). The high similarity of data sets from widely separated units supports long-held stratigraphic correlations between the late Mesoproterozoic- Neoproterozoic Mackenzie and Amundsen basins. The breadth of the inferred fluvial system was at least 1200 km, much wider than any modern fluvial system on Earth. Zircon ages show mainly local provenance at the base of the Shaler Supergroup, with the gradual up-section introduction of more distal sources that closely match the ages of magmatic rocks characterizing the Grenville and Granite-Rhyolite Provinces of eastern and southern Laurentia, respectively. Two episodes of siliciclastic influx, represented by the Escape Rapids Formation and the younger Nelson Head Formation (Rae Group), correspond with periods of uplift and erosional unroofing that would have followed the two main phases of the Grenvillian orogeny, the Shawinigan (ca 1200-1140 Ma) and the Ottawan (ca 1090-1050 Ma). Carbonate rocks of the intervening Mikkelsen Islands Formation, and possibly correlative Tabasco Formation of the Mackenzie basin, are interpreted to record an interval of tectonic quiescence and subdued siliciclastic influx. Our work establishes a detrital zircon reference for late Mesoproterozoic-Neoproterozoic strata of northern Laurentia that is comparable with that of coeval sequences from the circum-North Atlantic region. These strata could have been deposited in similarly large interior basins, possibly connected to the Amundsen-Mackenzie and Borden basins. Such a paleogeographic scenario was likely only possible during a time of continental aggregation (e.g., supercontinent Rodinia), when orogenic belts extended between adjacent continental blocks and huge basins lay within the supercontinent's interior.
Summary(Plain Language Summary, not published)
The paper presents detrital zircon U-Pb data from sandstones from late Precambrian rocks of Northwest Territories (7 samples). High similarity of datasets from widely separated units supports long-held stratigraphic correlations between the Mackenzie and Amundsen basins and the existence of a braided river system was at least 1200 km, much wider than any modern fluvial system on Earth. Zircon ages show mainly local sources at the base of the succession with the gradual up-section introduction of sources that match closely the ages of rocksin eastern North America. Two episodes of sand influx to the basins, correspond with the two main phases of Grenvillian mountain building episode, the Shawinigan and the Ottawan orogenies. Our work establishes a detrital zircon reference for late Precambrian rocks of northern Canada, which is comparable with that of coeval rocks from the circum-North Atlantic region.
GEOSCAN ID299227