The Fairbanks and Rampart Quadrangles, Yukon-Tanana Region, Alaska, Ausgabe 408U.S. Government Printing Office, 1910 - 102 Seiten |
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adit altered andesite basalt beds biotite Blue Jacket bodies Bull Run Bullion calcite camp Carboniferous carry Centennial Range chalcopyrite chloride claim composed of quartz considerable contact-metamorphic copper carbonates Cortez Range country rock Creek crosscut dark deposits developed Devonian dikes diorite dips east Edgemont Elko eruptive Eureka Expl fault feet wide feldspar fissure veins flows formed galena garnet geologic granite granodiorite gray copper groundmass gulch hornblende igneous rocks incline intrusive iron oxide iron-stained limestone lode Lone Mountain mass Midas miles Mill Canyon mine.-The Mineral Hill mines Mountain City Nevada northeast northwest orthoclase outcrop Owyhee Owyhee Bluffs Paleozoic phenocrysts places porphyry pyrite quartz monzonite quartz porphyry quartzite rhyolite ridge sedimentary rocks sericite shaft shales shaly sheeted zone Shoshone Range siliceous silicified slope Standing Elk stopes strikes sulphides sunk surface Tertiary thick tunnel is driven Tuscarora U. S. Geol Valley veinlets zinc blende
Beliebte Passagen
Seite 16 - Gray, compact limestone; lighter in color than the Hamburg limestone, traversed with thin seams of calcite; bedding planes very imperfect. Prospect Mountain quartzite. 1,500 Bedded brownish-white quartzites, weathering dark brown; ferruginous near the base; intercalated thin layers of arenaceous shales; beds whiter near the summit. reconnaissance. Devonian fossils have been described0 from several places in the Pinyon Range, among them Chimney station, Hot Spring Creek, and Pinyon Pass.
Seite 9 - The report includes brief descriptive notes on the geology and ore deposits of the following camps: Gold Circle (Midas), Tuscarora, Lime Mountain, Edgemont, Aura, Columbia, Mountain City, Van Duzer Creek, Cornucopia, Good Hope, Burner, Falcon, Lone Mountain, Palisade (Safford district), Bullion (Railroad district), Mineral Hill, Alpha, Lynn, Cortez, Mill Canyon, Dean, Lewis, Maysville, Pittsburg, Hilltop, Tenabo, Lander, Mud Springs, and Grey Eagle. FIELD WORK AND ACKNOWLEDGMENTS. The. work in the...
Seite 12 - Basin range structure of the Humboldt region. Bull. Geol. Soc. America, vol. 15, 1904, pp.
Seite 76 - The ore deposits are fissure veins in siliceous sedimentary rocks which are steeply tilted, folded, and faulted. The prevailing country rock is a brown or gray quartzite of rather uniform grain. The ore is highly siliceous and carries more than 90 per cent of quartz.
Seite 16 - Devonian 6,000 gray color, passing up into strata distinctly bedded, brown, reddish brown, and gray in color, in places finely striped, producing a variegated "appearance; upper rocks massive, well beaded, bluish-black in color; highly fossiliferous.
Seite 79 - Florae 13.— Generalized section through Bull Run mine, S. 10° E. from tunnel 1 to tunnel 4. shales have been contorted by compressive movements that took place before the deposition of the ore. The deposit is a well-defined fissure vein which has a maximum width of about 6 feet. It strikes northeast and dips from 22° to 38° SE. The quartzite is sheeted parallel to the vein and in places its apparent stratification is parallel to the vein, but on the surface, where the true dip may more easily...
Seite 72 - Blue Jacket mine. — The Blue Jacket mine is located at the head of Blue Jacket Creek near the divide between this stream and Silver Creek. The deposit was worked through two tunnels and a deep shaft, all of which were inaccessible when the mine was visited. The 116...
Seite 16 - Black argillaceous shales, more or less arenaceous, with intercalations of red and reddish-brown friable sandstone, changing rapidly from one locality to another; plant impressions.
Seite 72 - FIGUKE 7.— Cross section of Big Four lode, Columbia. being rich enough to pay for shipment. Near the lower tunnel the vein and the inclosing limestone are in faulted contact with granodiorite, as shown by figure 7. Columbia Queen mine. — The Columbia Queen mine, formerly the Bonanza, is on the west side of Columbia Creek, about 300 yards west of the Big Four mine. Like the Infidel and Revenue, it was the property of the Stokes Company, which operated it in 1875. The deposit, which resembles that...
Seite 12 - SPURR, JE Origin and structure of the basin ranges. Bull. Geol. Soc. America, vol. 12, 1901, pp.