The mine is characterized by Keweenawan
rock and Kincaid breccia just north of the site, Baker noted.
In support of the scientific results of the numerous Lithoprobe researchers, the authors bring in evidence from many facets of Earth Science, including fossils, the atmosphere, and sedimentary rocks, to address the question "It's a great story, but is it true?" Chapter 5, 'Breaking Up', takes us to Africa and our own origins, a 1698 'pygmy' on a ship in London, and the rifts where 'Africa is busily trying to tear itself apart'--possibly a modern analogy to the billion year old Keweenawan
rift in North America.
The Keweenawan Rift represents an ancient example of such collision-induced rifting.
Collision-induced rifting: The Grenville Orogeny and the Keweenawan rift of North America.
LaBerge (1997) suggests that the arsenopyrite may have been emplaced during igneous activity associated with the 1,100-million-year-old Keweenawan
mid-continent rift system.
This event has long been considered as a precursor to the 1.109-1.085 Ga Keweenawan event [#17a] located at the southwest end of the swarm (next entry).
1.11-1.08 Ga: One of the most dramatic flood basalt events in Canada and the United States is arguably the Keweenawan magmatism [#17a] of the Mid-Continent Rift (e.g.
km of the Canadian Shield, to young flood basalts, such as the rift-related Keweenawan Group and the accreted oceanic plateau, Wrangellia, in the Cordillera.
1.1 Ga mid-continental Keweenawan
Rift system (Fig.