The Magnetite Deposits of the Eastern Mesabi Range, MinnesotaUniversity of Minnesota, 1919 - 58 Seiten |
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The Magnetite Deposits of the Eastern Mesabi Range, Minnesota: Volume 17 Of ... Frank Fitch Grout,Thomas Monteith Broderick Keine Leseprobe verfügbar - 2018 |
Häufige Begriffe und Wortgruppen
15-minute silt algal structures amphibole analyses anorthosite basalt Biwabik Biwabik formation bodies Brass sand carbonate cent cherty cherty taconite clay content conglomerate Core sand County Cretaceous deposits diabase drill cores Duluth Duluth gabbro east Mesabi feet Floor sand Fort Snelling foundry gabbro Geol geologic glacial drift gorge grains granite granules gravel greenalite grey iron Gunflint hematite Highway Hise horizon Huronian inches iron formation iron oxides iron-bearing formation Jordan formation Lake Superior lava flows layers Leith limestone loams loess Lower Cherty magnetic magnetite material Mesabi Range mesh miles mineral Minn Minneapolis Minnesota Mississippi molding sand moraine outcrops Paul pebbles permeability Peter formation Peter sandstone Plate Pokegama probably quartz Quartz sand quartzite region River road samples sandstone screen shale shore silica Slaty division stream surface taconite Taylors Falls tensile strength tested green texture thickness tion trout valley
Beliebte Passagen
Seite 112 - Rocks formed by the cooling and solidification of a hot liquid material, known as magma, that has originated at unknown depths within the earth. Those...
Seite 114 - ... layers of lava particles blown from a volcano. A fine tuff is often called volcanic ash and a coarse tuff breccia. Type locality. The place at which a formation is typically displayed and from which it is named ; also the place at which a fossil or other geologic feature is displayed in typical form. Unconformity. A break in the regular succession of sedimentary rocks, indicated by the fact that one bed rests on the eroded surface of one or more beds "which may have a distinctly different dip...
Seite 114 - Weathering. The group of processes, such as the chemical action of air and rain water and of plants and bacteria and the mechanical action of changes of temperature, whereby rocks on exposure to the weather change in character, decay, and finally crumble into soil.
Seite 112 - Gneiss (pronounced nice). A rock resembling granite, but with its mineral constituents so arranged as to give it a banded appearance. Most gneisses are metamorphic rocks derived from granite or other igneous rocks. Granite. A crystalline igneous rock that has solidified slowly deep within the earth. It consists chiefly of the minerals quartz, feldspar, and one or both of the common kinds of mica, namely, black mica, or biotite, and white mica, or muscovite. The feldspar is the -kind known as orthoclase,...
Seite 113 - Some sedimentary deposits (tuffs) are composed of fragments blown from volcanoes and deposited on land or in water. A characteristic feature of sedimentary deposits is a layered structure known as bedding or stratification. Each layer is a bed or stratum . Sedimentary beds as deposited lie flat or nearly flat.
Seite 105 - Contributions to the geology of the Mesabi range, with special reference to the magnetites of the iron-bearing formation west of Mesaba [Minnesota]: Minnesota Geol.
Seite 113 - Sedimentary rocks. Rocks formed by the accumulation of sediment in water (aqueous deposits) or from air (eolian deposits). The sediment may consist of rock fragments or particles of various sizes (conglomerate, sandstone, shale); of the remains or products of animals or plants (certain limestones and coal); of the product of chemical action or of evaporation (salt, gypsum, etc.); or of mixtures of these materials.
Seite 42 - London, 1897, vols. i and 2. 03 Op. cit., vol'. 1, p. 198. It thus appears that during the volcanic activity there must have been intervals of such quiescence, and such slow, tranquil sedimentation in clear, perhaps moderately deep water, that a true radidarian ooze gathered over the seabottom.
Seite 111 - ... bomb. Breccia (pronounced bretch'a). A mass of naturally cemented angular rock fragments. Crystalline rock. A rock composed of closely fitting mineral crystals that have formed in the rock substance as contrasted with one made up of cemented grains of sand or other material or with a volcanic glass. Diabase. A heavy, dark intrusive rock having the same composition as basalt, but, on account of its slower cooling, a more crystalline texture. Its principal constituent minerals are feldspar, augite,...
Seite 42 - ... Perrot's proclamation in 1689 and by the Relation of Penicaut in 1700. A cross had been set at its mouth, as noted by Penicaut, probably to mark the grave of some French trader or voyageur. La Harpe, writing of Le Sueur's expedition in 1700, which was the theme of Penicaut's Relation, described this stream as "a great river called St. Croix, because a Frenchman of that name was wrecked at its mouth.