Browsing by Subject "metamorphic"
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Item Guidebook 2. Field Trip Guide Book for Lower Precambrian Volcanic-Sedimentary Rocks of the Vermilion district, Northeastern Minnesota(Minnesota Geological Survey, 1972) Ojakangas, R.W.; Morey, G.B.The present investigation, carried out since 1962 as part of continuing studies of the Lower Precambrian rocks of northern Minnesota, has consisted of broad regional geologic mapping in the western half of the district and adjacent areas (Sims and others, 1968; Sims and others, 1970) and detailed mapping and study of critical areas (Gabbro Lake quadrangle, Green and others, 1966; and Green, 1970; Isaac Lake quadrangle, Griffin and Morey, 1969; Embarrass quadrangle, Griffin, 1969; Tower, Shagawa Lake, and Ely quadrangles, unpublished maps). Systematic geologic mapping has not been carried out in the eastern part of the district as a part of the present re-study; however, the excellent geologic map of Gruner (1941) in the type area of the Knife Lake Group remains a useful one, and S.S. Goldich, G.N. Hanson, and associates have examined critical areas in the Saganaga Lake Northern Light Lake area as part of regional geochronologic studies. This field trip starts a few miles south of Ely and ends a few miles west of Tower, and is designed as a two-day trip. Typical outcrops of all formations in the district are included, but most stops will examine the Lake Vermilion Formation. The rocks that will be seen on this trip are tightly folded and steeply plunging; therefore, we will be looking at a cross-section (but a structurally complicated one) of a volcanic-sedimentary pile. All the rocks in the area are metamorphosed, but for simplicity the prefix "meta" will generally be omitted.Item M-197 Bedrock Geology of the International Falls and LittleFork 30' x 60' Quadrangles, northern Minnesota(Minnesota Geological Survey, 2014-09-25) Jirsa, Mark A.; Boerboom, Terrence J.; Chandler, V.W.The map depicts a complex history of volcanism, sedimentation, intrusion, multiple events of migmatization involving partial melting and melt dispersion, and several periods of deformation and metamorphism. It lies within the southern exposed extent of the Archean Superior Province. In northern Minnesota, the province is divided into three major tectonomagmatic terranes known as the Wabigoon, Quetico, and Wawa subprovinces. The publication shows the locations of mapped bedrock outcrops, structural measurements, interpreted bedrock geology in both map and cross-section views, and associated explanations. Ancillary imagery includes maps of regional geologic setting, index of archived mapping incorporated into this interpretation, and schematic depiction of geologic history.