Geology of the Northwest Territories province from dikes and mafic lava flows, overlain by deep ocean turbidite deposits. These rocks are believed to be the remains of oceanic crust that ended up preserved, surrounded on all sides by felsic volcanic rocks and granitoid plutons. In the area of Snofleld Lake in the northern part of the Slave Province, the remains of Archean stromatolites are preserved in a dolomite unit between felsic volcanic and greywacke-mudstone turbidites, some of the earliest evidence of life, forming in the shallows around volcanic islands. Around 1.27 billion years ago in the Proterozoic, a series of major magmatic events affected the
Geology of Saint Pierre and Miquelon Geology of Saint Pierre and Miquelon The geology of Saint Pierre and Miquelon is part of the 680 to 550 million year old, late Proterozoic Avalon Zone, a part of the Canadian Appalachians. The oldest rocks are 615 million year old metasedimentary and metavolcanic rocks, intruded by diorite and trondhjemite in the Cap de Miquelon Group. The metamorphic rocks are descended from an earlier volcanic arc-marine platform, rather than more ancient basement rock from the Avalonian microcontinent. The St. Pierre Group formed 581 million years ago with felsic and pyroclastic flows. Together with mafic rocks and andesite, they are evidence