Grenville orogeny Grenville orogeny The Grenville orogeny was a long-lived Mesoproterozoic mountain-building event associated with the assembly of the supercontinent Rodinia. Its record is a prominent orogenic belt which spans a significant portion of the North American continent, from Labrador to Mexico, as well as to Scotland. Grenville orogenic crust of mid-late Mesoproterozoic age (c. 1250–980 Ma) is found worldwide, but generally only events which occurred on the southern and eastern margins of Laurentia are recognized under the "Grenville" name. These orogenic events are also known as the Kibaran orogeny in Africa and the Dalslandian orogeny in Western Europe. The problem of
Sonoma orogeny arcs, composed of volcanic and volcaniclastic strata and paired geotectonically with Sonoma accretionary prisms to the east, are present in the Klamath-Sierran region of the Cordilleran orogen to the south of volcanic cover in the Pacific Northwest. Burchfiel and Davis presented a detailed model relating the Sonoma orogeny to convergent plate tectonic processes. They postulated an east-dipping subduction zone beneath a magmatic arc to the west of the continent. In this scheme, a back-arc basin floored by oceanic crust lay between the arc and the continent. The Sonoma orogeny involved closure of this basin and a process by which the