Diamonds – Slave / Churchill Provinces

The scientific research and results of this project are available via GEOSCAN.

The Diamonds – Slave / Churchill Provinces project, part of the Geo-mapping for Energy and Minerals (GEM) program, aims to develop a regional image of the lithosphere beneath the Slave and Churchill provinces of Nunavut and the Northwest Territories.

Project leader –  Bruce Kjarsgaard

Hypothesis:

Can diamonds survive re-working of the lithospheric mantle and be brought to surface by kimberlites  emplaced along the margins of Archean cratonic sub-domains?

Research objectives:

  • mapping the lithospheric mantle (~40 - 220 km depth) structure and evolution through joint teleseismic–magnetotelluric soundings and transects;
  • analyzing the thermal state, composition, age and evolution of the lithospheric mantle (~40 - 220 km depth) through studies of mantle xenoliths from kimberlite pipes and studies of diamonds and their inclusions;
  • analyzing the thermal state, composition, age and evolution of the lower crust (10-40 km depth) through studies of crustal xenoliths from kimberlite pipes;
  • defining the regional context of the Chidliak kimberlite field through a high-resolution aeromagnetic survey of Hall Peninsula; and
  • understanding the glacial dispersal processes of diamond indicator minerals in eskers through targeted detailed studies.

Scientific Highlights

  • Revised geotherm model (FITPLOT) provides a more robust knowledge of the thickness of the diamond stability window than conventional understanding.
  • Revised understanding of the age, composition and evolution of the Slave lithosphere.
  • Mapped dipping discontinuities at 90–110 km depth beneath the southeast margin of both the Slave and Rae cratons that indicate that these diamond-bearing mantle blocks are more extensive at mantle depths than as mapped at the surface.
  • Enhanced calibrations and analytical protocols for single grain thermobarometers and thermometers with applications to geotherm modelling.
  • Assembled diverse observations that develop an exploration model in which diamonds and kimberlite eruptions preferentially originate in mantle regions enriched by carbon dioxide, water and methane.

Information about other GEM mineral projects is available on the Geo-mapping for minerals web page.