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Browsing Guidebook Series by Author "Morey, G.B."
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Item Guidebook 12. Field Trip Guidebook for the Precambrian Geology of East-Central Minnesota(Minnesota Geological Survey, 1979) Morey, G.B.The bedrock geology of east-central Minnesota --generally bounded by latitudes 45 ON. to 47° N. and longitudes 92° 15' W. to 95° W. --is particularly interesting because the area contains a wide variety of igneous, metamorphic, and sedimentary rocks which span the entire range of Precambrian time. Unfortunately much of the bedrock is not well exposed. Those rock units that do crop out tend to occur as clusters 2 or 3 acres large or as strings 1 or 2 kilometers long; and these outcrop areas are widely separated by vast expanses of Pleistocene and Holocene materials as much as 140 thick. Therefore aeromagnetic and gravity data, and to a lesser extent, water-well and exploration records acquired over the years by the Minnesota and U.S. Geological Surveys were used to prepare a preliminary and somewhat generalized bedrock geologic map of east-central Minnesota at a scale of 1:500,000 (Morey, 1978).Item Guidebook 13. Field Trip Guidebook for the Archean and Proterozoic Stratigraphy of the Great Lakes Area, United States and Canada(Minnesota Geological Survey, 1979) Morey, G.B.This guidebook is prepared for the field excursion accompanying the Fifth Meeting of the International Union of Geological Sciences Subcommission on Precambrian Stratigraphy, to be held September 4-19, 1979, in the Great Lakes area, United states and Canada. Separate segments of the guidebook were prepared by the various field trip leaders and assembled by G. B. Morey, editor. M. J. Frarey coordinated the separate contributions for the Canadian part of the field excursion. The main purpose of the field excursion is to examine classic Precambrian sequences in the Lake Huron and Lake Superior regions, as a background for discussions on possible subdivision of the Archean and Proterozoic. The field excursion will be followed by technical sessions held in the Duluth, Minnesota, area.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 Guidebook 9. Field Trip Guidebook for Stratigraphy, Structure and Mineral Resources of East-Central Minnesota(Minnesota Geological Survey, 1979) Morey, G.B.; Davidson, D.M. JrEarly in the 20th century, east-central Minnesota became the source of appreciable quantities of iron and ferromanganese, and even earlier, the source of a variety of granite products (Morey, 1977). Because of the obvious economic importance of the commodities to the state, most of the geologic work in east-central Minnesota focused on the Cuyuna iron-mining district or on the St. Cloud area where there are numerous granite quarries. Less attention was given to the geology of other parts of east-central Minnesota and to the possible presence of other mineral resources. This was true mainly because a fairly ubiquitous mantle of Quaternary materials made it difficult, time consuming and expensive for a company to establish the basic geologic information necessary to a successful exploration program. However, recent geologic work (Morey, 1978) has led to the recognition of several geologic environments that are similar to mineral-producing districts elsewhere in the world (Morey, 1977). Although these studies have shown that a variety of mineral occurrences may exist, most attention to date has focused on environments that may contain uranium. This road log starts at the Minnesota-Wisconsin border along the st. Louis River near Fond du Lac, the westernmost suburb of Duluth, Minnesota, and terminates near Sturgeon Lake on U.S. Interstate Highway 35 some 50 miles southwest of Duluth. Note that the mileages in this road log are approximate.