|Title||Constraints on large-scale geological processes from small-scale magnetotelluric imaging in the Kaskattama Highlands, northeastern Manitoba, Canada|
|Author||Ferguson, I; Craven, J; Roberts, B; McLeod, J; Clark, N; Zaporozan, T; Hodder, T; Nicolas, M|
|Source||27th IUGG General Assembly, 2019, Montreal, Canada: abstracts; IUGG19-1630, 2019 p. 1 Open Access|
|Links||Online - En ligne (complete volume - volume complet, ZIP,
|Alt Series||Natural Resources Canada, Contribution Series 20190418|
|Publisher||International Union of Geodesy and Geophysics|
|Meeting||27th IUGG General Assembly; Montreal, QC; CA; July 8-18, 2019|
|File format||pdf; html|
|NTS||54A/05; 54A/11; 54A/12; 54A/13; 54A/14; 54B; 54G/01; 54G/02; 54G/03; 54G/04|
|Lat/Long WENS|| -92.0000 -89.0000 57.2500 56.0000|
|Subjects||tectonics; geophysics; Science and Technology; Nature and Environment; geophysical surveys; magnetotelluric surveys; bedrock geology; lithology; sedimentary rocks; shales; trend surface analyses;
geological history; depositional history; tectonic history; tectonic setting; subsidence; Superior Boundary Zone; Winisk River Fault; Phanerozoic; Mesozoic; Cretaceous; Precambrian|
|Program||GEM2: Geo-mapping for Energy and Minerals Hudson/Ungava Geophysics - Mount Southampton and Kaskattama Highlands|
|Released||2019 07 01|
|Abstract||A 22 site magnetotelluric (MT) survey conducted in the Kaskattama Highlands, northeastern Manitoba, Canada, in summer 2017 as part of the Canadian GEM 2 program provides good resolution of an underlying
Cretaceous shale unit. The shale occurs in an area where a drill-hole reveals anomalous Paleozoic stratigraphy including the presence of the shale and absence of some Silurian units. Underlying Precambrian basement rocks include the Fox River Belt of
the Superior Boundary Zone, close to its truncation by the Winisk River Fault. The shale unit has a resistivity of 9 ?.m and a moderately uniform conductance (thickness-conductivity product) across the survey area. MT results show the unit extends 15
to 30 km in the northwest-southeast direction beneath the highlands and at least 20 km in the southwest-northeast direction. Collectively, the results suggest the shale has a marine source. Mesozoic to Cenozoic sediments occur locally in Hudson Bay
and the current study provides evidence for a larger distribution of such sediments and of postulated periodic connections with other marine domains. The results provide evidence of localized post-Silurian, pre-Cretaceous uplift, causing the erosion
of Silurian units, and subsequent post-Cretaceous subsidence to preserve the shale unit. The interpreted vertical tectonic processes may be attributed to large-scale Phanerozoic reactivation on the Superior Boundary Zone or the Winisk River Fault,
and/or possibly to processes associated with Cretaceous mantle plume activity. |
|Summary||(Plain Language Summary, not published)|
In 2017, as part of the Canadian GEM 2 program, a study was conducted in the Kaskattama Highlands of northeastern Manitoba, Canada. The objective was to
understand the geological features of the region. The researchers conducted a magnetotelluric (MT) survey at 22 sites, which helped them see what lies beneath the Earth's surface.
The key discovery was a shale unit dating back to the Cretaceous
period. This shale layer, with specific electrical properties, was found under the Kaskattama Highlands. It extends for about 15 to 30 kilometers in one direction and at least 20 kilometers in another.
The presence of this shale suggests that it
was formed in a marine environment. The study also revealed the presence of sediments from the Mesozoic to Cenozoic periods in Hudson Bay, indicating connections with other marine regions.
This research provides valuable insights into the
geological history of the area, showing that there were uplift and subsidence events over millions of years. It's important because it helps scientists understand the Earth's complex history, including the movement of tectonic plates and geological
processes that have shaped the landscape.