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 .
Cpx, garnet, ilmenite and olivine megacrysts from the 172 my old Muskox kimberlite in Nunavut were analyzed for major and trace elements. Muskox is located approx. 15 kilometers southwest of the Jericho kimberlite which was mined for several years in the 2000s. The goal of the study was "to unravel the genetic relationship between megacrysts and their host kimberlite, explore possible mechanisms of metasomatic megacryst genesis and constrain the composition of the metasomatic agent". The resulting data suggests that the megacrysts and websterites may be the result of regional metasomatism by carbonatitic fluids predating the kimberlite magmatism.
The authors use extensive geologic and geophysical data from the Superior craton region of North America and the results of seismic tomography studies under the Hudson Bay Lithospheric Experiment to form a model for the evolution and structure of the sublithospheric mantle underneath Hudson Bay. They conclude that Hudson Bay lies directly above the lithospheric keel of North America and they found no evidence that there was production or transformation of the lithosphere during the Paleoproterozoic. A vertical axial zone detected in the lithosphere beneath Hudson Bay is discussed. They postulate that this zone is made up of relatively light low-velocity igneous rocks, possibly a swarm of kimberlite dykes or pipes.
This brief note summarizes recent research published in Nature regarding the stabilization of the lithoshpere. The following summarizes the goal of the research. "The fact that cratons are so thick and enduring poses a problem for scientists. To make really thick lithosphere requires a good deal of deformation. How do we create long-lived, stable features out of material that was once deformable?" It is suggested that the lithoshpere becomes stronger as parts of it are extracted as melt. The melt comes up through the lithospheric mantle to form crust leaving behind a thicker, stronger and cooling mantle embedded in the lithosphere forming the roots of the continents.
It's been well-documented that ants or termites can play a role in bringing kimberlite indicator minerals from depth to the surface. Successful sampling of termite mounds had a role in the discovery of Orapa by De Beers in the 1960s and the method is being used by Pangolin today in their Botswana exploration programs. Ant hills were sampled as part of some kimberlite exploration programs in the western USA. This paper is silent on diamond exploration but summarizes the effects ants, which first came on the scene in the Cretaceous, can have on geomorphological processes.