Bulletin of the United States Geological SurveyThe Survey., 1910 |
Andere Ausgaben - Alle anzeigen
Häufige Begriffe und Wortgruppen
Alaska American Creek amount angular basin bed rock Bendeleben Mountains Big Four Creek Big Hurrah Creek biotite Brooks calcite Casadepaga Casadepaga quadrangle Casadepaga River Casadepaga schist character chlorite cleavage coastal plain Collier country rock creek gravels deformation deposits distribution ditch drainage dredge East Fork elevation erosion evidence fault feet feldspar folded formation formed fragments geologic maps gold granite graphitic gravels greenstones Gulch heavy limestone Hurrah slate intrusion Kigluaik group Kigluaik Mountains less limestone lower material metamorphism miles minerals mining Moffit Mount Dixon Mount Osborn mouth Niukluk Niukluk River Nome group occur Ordovician origin outcrops pebbles places Plate Port Clarence portion present probably prospecting quartz Quartz Creek quartz veins reconnaissance region reported Sam Mountain seems Seward Peninsula sheared Shovel Creek slope sluice Solomon and Casadepaga Solomon River Solomon schist Sowik limestone structure sulphides surface Survey thickness tion tributaries U. S. Geol upper valley
Beliebte Passagen
Seite 197 - Reconnaissances in the Cape Nome and Norton Bay regions, Alaska, in 1900.
Seite 108 - Furthermore, the granite bowlders are unweathered, showing that they have not been in their present position a very long time geologically. Although the question has not been carefully studied in the field, it is suggested that possibly these bowlders have been brought by glaciers from Kigluaik Mountains and carried into their present position by ice blocks floating on a lake formed by glacial obstruction of the drainage. This suggestion is to be regarded only as a working hypothesis, but it fits...
Seite 29 - A second group of basic rocks is composed of unaltered basalts. which occur at many places in the northern and eastern parts of the peninsula. Typically they are dark-gray or nearly black lavas, usually very cellular or even spongy in appearance, but in some places compact and without amygdaloidal cavities. They are diabases and basalts, both rich in olivine. In the basalts especially olivine phenocrysts are abundant and are noticeable even in the hand specimen. Rocks of this type find their greatest...
Seite 99 - ... bulk of the alluvium. In all the smaller streams and in parts of the larger ones a bed of clay or sandy clay, in which more or less vegetable matter is intermingled, forms the topmost layer. This surface bed, which varies in thickness from 2 to 30 feet and is called by the miners "tundra...
Seite 73 - The most striking example of this is seen in the cliff exposures just eaM of the mouth of Daniels Creek (fig. 15). Here an irregular mass of mica schist is inclosed in limestone walls. Lines of faulting have obscured the original relation of the two rocks, but the outline...
Seite 108 - The angular, un weathered form and foreign character of the granite and the presence of shore lines at considerable elevations. Lakes of this type are common in regions that are at present glaciated, and evidences of such lakes have been recognized in many places where glaciers have now disappeared.
Seite 155 - There was no mining on Solomon River below Big Hurrah Creek in 1900, but by 1903 there had been some developments a little above the mouth of Manila Creek. The placer here was described by Collier,° as follows : A river-bar deposit about 3 miles from the coast has been worked for two seasons by a dipper dredge. The pay streak here has an average width of about 200 feet and a thickness of 9J feet, most of the gold being concentrated in the lower part. It rests upon a soft mica schist bed rock, which...
Seite 73 - Here an irregular mass of mica schist is inclosed in limestone walls. Lines of faulting have obscured the original relation of the two rocks, but the outline of the schist mass is very suggestive of an a Bull.
Seite 27 - Bering Sea coast for about 5 miles between the native village of Palazruk and the granite outcrop a Bull. US Geol. Survey No. 328, 1908, pp. SI. GEORGE OTlS SMlTH BULLETlN 433 PLATE ll LEGEND of Cape Mountain. Near Palazruk they are intensely crushed and probably faulted.
Seite 28 - Creek, where they are associated with deposits of lignitie coal. These beds are folded and much jointed, but have not been altered to the same degree as have the neighboring schists. They have the same north-south strike and high dips common in the highly metamorphic rocks, and, when weathered, their altered surfaces present an appearance very similar to that which would have resulted had they be'en burned. Such outcrops were noticed on Kugruk River near the mouth of Chicago Creek and for several...