| Title | Zircon provenance data record the lateral extent of pancontinental, early Neoproterozoic rivers and erosional unroofing history of the Grenville orogen |
| |
| Author | Rainbird, R H ;
Rayner, N M; Hadlari, T; Heaman, L M; Ielpi, A; Turner, E C; MacNaughton, R B |
| Source | Geological Society of America Bulletin 2017 p. 1-16, https://doi.org/10.1130/b31695.1 |
| Image |  |
| Year | 2017 |
| Alt Series | Earth Sciences Sector, Contribution Series 20160172 |
| Publisher | Geological Society of America |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Northwest Territories; Yukon |
| NTS | 77; 87; 88; 86I; 86J; 86K; 86L; 86M; 86N; 86O; 86P; 96I; 96J; 96K; 96L; 96M; 96N; 96O; 96P; 97; 106; 107 |
| Area | Mackenzie Basin; Victoria Island |
| Lat/Long WENS | -136.0000 -108.0000 74.0000 64.0000 |
| Subjects | geochronology; 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 |
| Illustrations | location maps; stratigraphic columns; diagrams; stratigraphic correlations |
| Program | GEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Shield to Selwyn |
| Released | 2017 06 30 |
| Abstract | We 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 ID | 299227 |
|
|