The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcements called the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The SDLRC Blog is a guest commentary by an industry expert about articles, themes and trends in recent issues of the SDLRC.
Comments by Brooke Clements
Brooke Clements is President and CEO of Craton Minerals Ltd., a Vancouver-based private diamond exploration company focused on discovering North America's next diamond district. He is also President of JBC Ventures Ltd., a consulting company specializing in mineral exploration and community and government relations. From 2007 to 2015 he was President of Peregrine Diamonds Ltd. where he led the team that discovered the Chidliak diamond district on Baffin Island in the Canadian Arctic. Before that, Brooke was Vice President, Exploration for Ashton Mining of Canada Inc. Under his leadership, Ashton and their partner SOQUEM discovered the Renard diamond district in Quebec where the Renard Diamond Mine commenced production in 2016. From 1982 to 1997, Brooke was an Exploration Geologist and Regional Manager for Exmin Corporation where he conducted diamond exploration programs throughout the United States. He holds a BSc in Geology from Indiana University and an MSc in Economic Geology from the University of Arizona.
Brooke Clements has volunteered to highlight the scientific articles that caught his attention in the monthly reference compilations. The opinions expressed are solely his and he can be reached at .
It's worth reminding everyone that the link Pat provides every month to media-corporate items in the Kaiser Research Online Diamond Center is a tremendous resource. The archive contains some company news releases, excerpts from some diamond newsletters and references to business articles. This month there is an interesting newspaper article about the mysterious 34 carat Punch Jones diamond found during a game of horseshoes in West Virginia in 1928. There are a number of confirmed diamond finds throughout the United States, without a known source area. The three most prominent areas are the south margin of continental glaciation in the midwestern USA, California and the southeastern USA. One isolated diamond occurrence shrouded in mystery that has received a lot of attention lately is the 800 ct. yellow Nipissing diamond, which was found near Cobalt, Ontario, Canada in the early 1900s. There has been increased exploration in this region of late, most notably by RJK Explorations and Tres-Or Resources, and some speculation on potential linkage between their projects and the Nipissing diamond.
This paper is chapter 7 in a monograph entitled "Mantle Convection and Surface Expressions, Geophysical Monograph". It is a good summary of what we have learned from the study of super-deep diamonds which are thought to have formed at depths of 300-800 km in the sub-lithospheric mantle. Many large and high-value diamonds have been classified as super-deep.
Information on regional surfaces causing discontinuities in seismic waves a few hundred kilometers deep in the Earth and xenolith data from kimberlites in the Victor, Kyle Lake, Kirkland Lakd and Temiskaming areas in Ontario, is interpreted to map crustal blocks in portions of Ontario and Quebec underlain by the Superior craton.
In 2011, Gem Diamonds began construction of the Ghaghoo diamond mine, Botswana's first underground diamond mine which targeted the Gope or Go25 kimberlite. The kimberlite is covered by 70 m of Kalahari sand and it was accessed using a decline shaft. The mine opened in 2014 but never met revenue expectations and was closed in 2017. This paper by Andy Moore, a member of the discovery team, tells the story of the Gope kimberlite's discovery by Falconbridge in 1981.
This paper emphasizes the importance of understanding magmaclasts in a kimberlite and provides a detailed classification scheme. There are lots of good photographs and diagrams. The authors conclude that the proper interpretation of magmaclasts can be critical in generating a robust and economically relevant geologic model of a kimberlite.
Diamond explorers prioritize areas where data suggests that the continental lithosphere and its mantle root have been coupled and stable for a long time. Traditionally, these areas are Archean cratons but recent work suggests that younger cratonic areas that meet these criteria could be good targets as well. This paper studies the interaction between continental drift and orogenic belts and these stable areas.