|Title||Into the unknown: surficial geological investigations in the south Rae area, Northwest Territories|
|Author||Campbell, J E; Lauzon, G; Dyke, A S|
|Source||Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume 2015, 2015 p. 20-21 Open Access|
|Links||Online - En ligne (complete
volume - volume complet, PDF, 1.68 MB)|
|Alt Series||Earth Sciences Sector, Contribution Series 20150322|
|Publisher||Northwest Territories Geological Survey|
|Meeting||43rd Annual Yellowknife Geoscience Forum; Yellowknife; CA; November 24-26, 2015|
|Media||paper; on-line; digital|
|Program||GEM2: Geo-mapping for Energy and Minerals South Rae Province Bedrock/Surficial geology|
|Released||2015 11 01|
|Abstract||The Geological Survey of Canada, as part of its Geo-Mapping for Energy and Minerals Program (GEM2), in partnership with the Northwest Territories Geological Survey, has begun a three-year (2015-2017)
project to upgrade the bedrock and Quaternary geoscience knowledge for the underexplored and predominantly drift-covered South Rae region in southeastern Northwest Territories. The surficial geology in this region has never been field mapped, and
as a result, the glacial history, regional drift provenance and Quaternary framework necessary for the implementation of successful mineral exploration, sustainable resource development and land-use management is lacking. In order to address in
these knowledge gaps, the Quaternary geological component of this project will: 1) increase the surficial mapping coverage; 2) define the regional drift composition and glacial transport characteristics; and 3) reconstruct the glacial history and
ice-flow sequences, particularly as they relate to the southwestern Keewatin Ice Sector and migrating ice divides.|
During the 2015 field season, surficial geological mapping and regional till sampling were completed in NTS map sheets 75A and B.
Targeted reconnaissance sampling, focused primarily on 4 transects, resulted in till samples collected at 88 sites for provenance, geochemistry, indicator minerals and gold grains. Multiple small and meso-scale erosional ice-flow indicators (e.g.
striations, grooves, roche moutonnée) were measured at 55 locations. To help establish a minimum age for ice-free conditions in this area, 3 samples were collected for age dating.
Preliminary mapping has identified at least 4-5 phases of ice
flow with 3 main flowsets variably affecting the study area. The oldest regional flow is to the south. The main regional flowset (Late Wisconsin deglaciation), is generally to the southwest. A younger, late stage, west flowing paleo-ice stream
overprints this southwest flow in the northern part of the study area. Rare SSE/ NWW flow indicators were noted but the relative age is unknown. Distinctive erratics, such as Dubawnt Supergroup lithologies, are derived from sources located at
greater than 200 km to the north-northeast and suggest sustained transport and dispersal of glacial debris by the older southward flow.
Drift cover of variable thickness is extensive, ranging locally from 30 to 100% coverage. The dominant
surficial material is till of varying composition, thickness and genesis. The landscape, particularly in map sheet 75B, is dominated by streamlined landforms with organic terrain in the lows. Numerous parallel subglacial meltwater corridors trend
WSW- SW across the map area (>200km) with two types of signature landform/deposits assemblages of the corridors: 1) eskers, parallel trains of either ice-contact glaciofluvial (hummocks and ridges) deposits or terraced glaciofluvial deposits, and 2)
trains of hummocky till, boulder lags with small discontinuous eskers and related deposits. New mapping indicate proglacial lakes were more extensive in this area than previously thought.
|Summary||(Plain Language Summary, not published)|
This presentation abstract provides the highlights for 2015 field investigations of the new Quaternary mapping component of the GEM2 Geologic and
Metallogenic Framework of the South Rae Craton project in Southeast NWT. The surficial geology of this heavily drift covered region has never been field mapped and little is known about its glacial history. The new data and information gather this
past summer improves our geoscience knowledge and will help update the Quaternary geological framework for this region. An improved geological framework will assist stakeholders to make informed decisions with respect to mineral exploration,
sustainable resource development and land-use management.