Title | Lithofacies in the type section of the mid-Neoproterozoic Ram Head Formation, Mackenzie Mountains, Northwest Territories |
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Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
Author | Stone, C; Turner, E C |
Source | Geological Survey of Canada, Open File 8616, 2019, 37 pages, https://doi.org/10.4095/315363 Open Access |
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Year | 2019 |
Publisher | Natural Resources Canada |
Document | open file |
Lang. | English |
Media | on-line; digital |
File format | pdf (Adobe® Reader®) |
Province | Northwest Territories |
NTS | 95M/14SW |
Area | Boomerang Lake; Mackenzie Mountains |
Lat/Long WENS | -127.4414 -127.4231 63.7850 63.7792 |
Subjects | stratigraphy; paleontology; Nature and Environment; Science and Technology; lithostratigraphy; lithofacies; type sections; geological history; depositional history; depositional environment;
sedimentation; diagenesis; tectonic history; deformation; sedimentary structures; bedrock geology; lithology; sedimentary rocks; mudstones; carbonates; dolostones; limestones; siltstones; grainstones; arenites; caliche; fossils; stromatolites;
clasts; Mackenzie Mountains Supergroup; Little Dal Group; Ram Head Formation; Neoproterozoic; Laurentia; Rodinia; Snail Spring Formation; Precambrian; Proterozoic |
Illustrations | location maps; stratigraphic sections; photographs; lithologic sections |
Program | GEM2: Geo-mapping for Energy and Minerals Mackenzie Corridor, Shield-to-Selwyn geo-transect, Mackenzie-Selwyn sub-activity |
Released | 2019 10 03 |
Abstract | The mid-Neoproterozoic Ram Head Formation is the uppermost formation of the Little Dal Group and Mackenzie Mountains Supergroup and records epicratonic sedimentation in northeastern Laurentia
immediately preceding the dispersal of supercontinent Rodinia. The Ram Head Formation can be broadly divided into two members: a lower and an upper member. The lower member comprises abundant metre-scale shallowing upwards cycles composed of below
wave-base molar-tooth dolomudstone, mechanically laminated dolomudstone and very rare and thin siltstone beds; and shallower water ooid-intraclast grainstones and stromatolites. The upper member begins with a pisolitic unit - interpreted to be a
caliche representing a significant period of exposure - and a deepening upwards cycle before the resumption of shallowing-upwards cycles. The upper member contains no molar-tooth dolomudstone, and has significantly more and thicker siltstone units as
well as terrigenous mudstone. A number of putative sedimentological evidences for synsedimentary tectonism are present throughout the formation and include: a sudden deepening-upwards cycle at the base of the upper member, locally abundant debrites
in the lower member, common soft-sediment deformation and local brittle deformation, and possible toppled stromatolites at the base of the Ram Head Formation. No synsedimentary faults have been observed. |
Summary | (Plain Language Summary, not published) This is a report of rock type descriptions from a measured section in a Neoproterozoic rock unit of the Mackenzie Mountains. It includes figures showing
the order of rock types and their thicknesses, as well as photographs of the rocks. |
GEOSCAN ID | 315363 |
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