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 received a B.Sc in Geology from Indiana University and an M.Sc in Economic Geology from the University of Arizona. From 1982 to 1997, he was an Exploration Geologist and Regional Manager for Exmin Corporation where he conducted diamond exploration programs throughout the United States. From 1998 to 2007 he was Vice President, Exploration for Ashton Mining of Canada Inc. Under his leadership, the Ashton-SOQUEM exploration team discovered the Renard diamond district in Quebec where Stornoway Diamonds opened the Renard Diamond Mine in 2016. 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. Currently, Brooke is President of JBC Ventures Ltd., a consulting company specializing in mineral exploration and community and government relations. He is also President and CEO of Craton Minerals Ltd., a private diamond exploration company focused on discovering North America's next new diamond district.
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 .
Yellowknife Geoscience Forum: Every year in late November, the week of American Thanksgiving, the Geoscience Forum is held in Yellowknife. Government researchers, industry geologists and engineers, suppliers, contractors and people from NWT communities gather to talk about geology, the mining business, and environmental, community and regulatory issues. It is a great networking event. Since the Lac de Gras discovery in 1991, the conference has had a lot of diamond content. This month there are titles and abstracts for 25 talks from the conference. The next kimberlite conference in 2021 will be in Yellowknife. As a warm up and to get a real feel for the north and see firsthand how diamond mining has transformed the NWT, consider going to the Geoscience Forum next November.
7th Brazil Diamond Conference: The 7th conference on the geology of diamond deposits in Brazil was held in Salvador, Bahia, Brazil in early November. There were 20 talks, the titles of which are included in this month's compilation (abstracts will be added once they become available). Brazil has always been an enigma. For decades, companies and prospectors spent millions of dollars in search of primary sources for the prolific alluvial diamond deposits without, until 2016, successfully defining an economic deposit. In 2016 Lipari Mineração opened its Brauna Mine in Bahia state, the first kimberlite mine in South America. The 2 ha kimberlite discovered by De Beers in 1992 has a grade of 0.27 cpt. The processing rate of the mine is 2,400 tonnes per day, the diamond value realized in 2017 was US $201/ct. and operating costs are listed at US $103/ct.
SEG Special Publication No. 20; Rio Tinto Deposit Volume: The long-awaited Rio Tinto Diamond deposit volume was issued by the Society of Economic Geologists in November. There are 20 excellent papers and an introduction. The volume opens with a paper on the tectonic and structural setting of diamond deposits by Herb Helmstaedt followed by 19 papers devoted to Argyle, Diavik, Murowe and Bunder. For each deposit, the discovery, geology, evaluation and diamonds are described. Those that did not get a free copy with their Botswana kimberlite conference registration can purchase this great reference from SEG, US$96 for members, $120 for non-members.
This free download covers many aspects of plate tectonics and its effect on the lithosphere. The authors conclude that there were significant changes in earth's behavior in the Archean between 2.5 and 3.2 Ga.
The Sask craton, which hosts the Fort A La Corne diamond district, lies within the Paleoproterozoic Trans Hudson Orogeny. It was defined in the 1990s as an Archean craton principally because the crustal rocks within the Glennie Domain were Archean in age. Research for this dissertation from the University of Alberta, which is a free download, focused on mantle xenoliths from kimberlites to assess the lithospheric mantle. Czas concludes that "the majority of the lithospheric mantle was depleted and stabilized in the Paleoproterozoic, significantly later than the Archean crust". Lithosphere formation is linked to 2.2 Ga rifting and the 1.9-1.8 Ga collision of the Superior and Hearne cratons during the Trans Hudson orogeny.
The nature of the lithosphere is one of the most critical features to understand when targeting areas for diamond exploration. This paper contemplates the link between the mantle lithosphere and plate tectonic processes.
This paper documents how Google Earth has crept into the lives of geologists. Google Earth is a spectacular tool for exploration geologists. Integrated with a GIS program, it allows us to effectively "visit" areas before goinig to the field. Geophysicists routinely use it to assess the ground characteristics of anomalies they see in the data.