hltonD eFF nd wrgoldD wF nd tokesD gFF nd rsovD vF nd hykeD eFF nd edmsD FF nd ellrdD F nd erendsD rFiF nd etkinsonD xF nd ettigD tF nd frnettD FtF nd frnettD FvF nd fttersonD wF nd fernthezD F nd forns trD rFF nd frekenridgeD eF nd frinerD tFF nd frourdD iF nd gmpellD tFiF nd grlsonD eFiF nd glgueD tFtF nd gurryD fFfF nd higneultD FeF nd hu¡ eEvouertD rF nd isterrookD hFtF nd prnziD hFeF nd priedrihD rFqF nd punderD F nd quthierD wFF nd qownD eFF nd rrrisD uFvF nd r¡ etuD fF nd rooyerD FF nd tenningsD gFiF nd tohnsonD wFhF nd uehewD eFiF nd uelleyD FiF nd uerrD hF nd uingD iFvF nd ujeldsenD uFuF nd uneleD eFF nd vjeunesseD F nd vkemnD FF nd vmotheD wF nd vrsonD F nd vvoieD wF nd voopeD rFwF nd vowellD FF nd vusrdiD fFeF nd wnzD vF nd wwrtinD sF nd xixonD pFgF nd yhiettiD F nd rkhillD wFeF nd iperD hFtFF nd ronkD eFqF nd ihrdD FtFrF nd idgeD tFgF nd ossD wF nd oyD wF nd emnD eF nd hwD tF nd teD FF nd ellerD tFF nd hompsonD FfF nd horleifsonD rFvF nd ttingD hFtF nd eilletteD tFtF nd rdD fFgF nd eddleD FuF nd right trD rFiF @PHPHA 9en updted rdioronEsed ie mrgin hronology for the lst deglition of the xorth emerin se heet gomplexF9D uternry siene reviewsFD PQR F pF IHTPPQF
Ice directional indicators were compiled from extensive field mapping and air-photo interpretation in the Keewatin region of central Nunavut. The profusion of multi-faceted bedrock outcrops, intersecting striations, superimposed streamlined landforms, and stacked till units, particularly beneath the former Keewatin Ice Divide, is interpreted to be the result of the migration of the main ice divide in the region, by as much as 500 km between ice-flow phases, possibly through much of the Wisconsinan glaciation. This palimpsest glacial landscape reflects protection under an ice divide because of low-velocity basal sliding, and changes in flow velocity as a result of shifting ice flow centres. Relative ages of regional ice-flow sets were used to reconstruct multiple phases of paleo-ice flows, stemming from ice centres external to the region prior to or at LGM, and from a local ice divide throughout deglaciation. This work refutes previous interpretations of the age and stability of the Keewatin Ice Divide, and has implications for interpreting glacial dispersal trains and for mineral exploration in Keewatin.Des indices d’écoulement glaciaire ont été compilés à partir d’une cartographie à grande échelle sur le terrain et à l’aide de la photo-interprétation dans la région du Keewatin au centre du Nunavut. L’abondance d’affleurements rocheux à facettes multiples, de stries entrecroisées, de formes profilées superposées et d’unités de till empilées, notamment sous l’ancienne ligne de partage glaciaire du Keewatin, est le résultat de la migration de la ligne de partage glaciaire principale sur 500 km dans la région du Keewatin au cours de la glaciation du Wisconsinien. Ce paysage glaciaire est le vestige d’un glissement minimal sous la ligne de partage glaciaire et des variations de vitesse d’écoulement causées par le déplacement des centres d’écoulement. Les âges relatifs des familles d’écoulement glaciaire ont permis de reconstituer de nombreuses phases glaciaires anciennes, qui sont affectées par les centres d’écoulement situés à l’extérieur de la région et par une ligne de partage glaciaire locale jusqu'à la déglaciation. Ces résultats réfutent les interprétations antérieures quant à l’âge et à la stabilité de la ligne de partage glaciaire du Keewatin et ils aident à mieux comprendre les trains de dispersion glaciaire et l’exploration minérale dans la région du Keewatin
This report presents the field database and analytical results from the Geological Survey of Canada's 2010 to 2012 surficial geology mapping and till sampling campaign in the north Wager Bay project area, mainland Nunavut. An overview of the Quaternary geology of this area is provided together with an interpretation of till provenance, as well as a discussion on the implications for mineral exploration. Field observations and surficial geological mapping indicate the region is key for the glacial history reconstruction of the northeastern part of the Keewatin Sector of the Laurentide Ice Sheet. Most of the study area was located within an extensive onset zone of a large ice stream flowing north into Committee Bay during the last glaciation and early deglaciation, from an ice divide located over and/or south of Wager Bay. Major ice-flow reversals into Repulse Bay and Wager Bay, as a result of drawdown into the opening marine waters in Hudson Bay, are indicated for the latest deglaciation phases. Coldbased ice remnant masses over the uplands north of Wager Bay preserved relict, weathered and fresh glacial landscapes at the end of deglaciation. Although there is evidence of multiple ice-flow directions in the study area, the main ice-flow phase, which converges north (NNE to NNW) towards Committee Bay, is the predominant direction of glacial transport and shaped most prominent streamlined landforms. The carbonate clast content and Al2O3 concentrations in surface till indicates relatively long glacial transport distances linked to glacial dispersal by the ice stream. Mg-rich olivine, many having >Fo90 and high NiO contents, are abundant in till in the center of the study area where a frost-shattered ultramafic lamprophyre boulder was found at the surface. Location of the boulder, its distinctive composition, and the olivine in till distribution in conjunction with the glacial transport history, suggest an ultramafic bedrock source other than kimberlite fields known in the region. In the western part of the study area south of Walker Lake, forsteritic olivine and chromite grains in till, locally coincident with ultramafic boulders, form a 35 km-long NNE dispersal train. This dispersal plume points to olivine-rich crustal rocks within undifferentiated Archean supracrustal rocks, and suggests these rocks have potential to host Ni-Cu-PGE mineralization. In addition to known Penhryn Group rocks and extensions of this belt to the southwest, there are suspected but poorly mapped strands of supracrustal rocks between Beach Pt and Wager Bay which show potential for base- and/or preciousmetal mineralization. More detailed till sampling, prospecting and bedrock mapping is required to better assess mineral potential in these areas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.