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At least 1,639 records · Page 91Linked to original sources
USGS1972

Pleistocene tectonic accretion of the continental slope off Washington

Interpretation of reflection profiles across the Washington continental margin suggests deformation of Cascadia basin strata against the continental slope. Individual reflecting horizons can be traced across the slope-basin boundary. The sense of offset along faults on the continental slope is predominantly, but not entirely, west side up. Two faults of small displacement are seen to be west-dipping reverse faults. Magnetic anomalies on the Juan de Fuca plate can be traced 40–100 km eastward under the slope, and structural interpretation combined with calculated rates of subduction suggests that approximately 50 km of the outer continental slope may have been formed in Pleistocene time. Rocks of Pleistocene age dredge from a ridge exposing acoustic “basement” on the slope, plus the results of deep-sea drilling off northern Oregon, are consistent with this interpretation. The question of whether or not subduction is occurring at present is unresolved because significant strain has not affected the upper 200 m of section in the Cascadia basin. However, deformation of the outer part of the slope has been episodic and may reflect episodic yield, deposition rate, subduction rate, or some combination of these factors.

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USGS1972

Geology and Mineral Resources of the Northern Part of the North Cascades National Park, Washington

The northern part of the North Cascades National Park in northern Washington is north of the Skagit River between Mount Shuksan on the West and Ross Lake on the east. The area occupies approximately 500 square miles of steep mountains and thickly forested valleys centered on the precipitous Picket Range. Old metamorphic rocks and young volcanic and sedimentary rocks are intruded by large masses of granitic rocks that together form a diverse, complicated, but well-exposed geologic section. The granitic rocks are the most abundant in the area; they intrude most of the other rocks, and they separate one suite of rocks in the eastern part of the area from a second suite in the western part. In the eastern part of the area, the oldest rocks are the Custer Gneiss of McTaggart and Thompson, a thick sequence of biotite and hornblende gneisses and schists. We have divided these rocks into three generalized units: light-colored gneiss, banded gneiss, and amphibole-rich gneiss. To the northeast of these rocks lies a metagabbro. This rock type is complex and is made up of several types of gabbro, diorite, amphibolite, ultramafic rocks, and quartz diorite that crop out along the Ross Lake fault zone. To the northeast of these rocks and also along the Ross Lake fault zone is the phyllite and schist of Ross Lake. These rocks are the highly sheared and metamorphosed equivalents of the plagioclase arkose and argillite sequence of Jurassic and Cretaceous age that is so widespread on the east side of Ross Lake. The Cretaceous Hozomeen Group of Cairnes lies along Ross Lake northeast of the phyllite and schist and consists mainly of slightly metamorphosed greenstones with subordinate chert and phyllite. The phyllite in this unit is similar to that in the underlying phyllite and schist of Ross Lake with which it appears to be interbedded. The youngest rocks in the eastern part of the area are the Skagit Volcanics a thick sequence of welded tuff-breccia with some flows and air-laid tuffs. These rocks, which are probably early Tertiary in age, overlie the Hozomeen Group and the Custer Gneiss along the Canadian border. In the western part of the area the oldest rocks are greenschist and phyllite of Mount Shuksan. These fine-grained foliated and crinkled rocks commonly contain narrow lenses or layers of quartz. They are unconformably overlain by the Chuckanut Formation in the southern part of the area. This formation, which is of Paleocene and Late Cretaceous age, is made up mainly of gently dipping plagioclase arkose with some interbedded black argillite and conglomerate. The Hannegan Volcanics overlie the Chuckanut in the northern part of the area and the greenschist and phyllite of Mount Shuksan in the central part. The Hannegan Volcanics which are of early Tertiary age, consist principally of air-laid volcanic breccias and tuffs, but also include some flows and one small porphyry stock. The Chilliwack composite batholith consists of several types of granitic rocks, which were intruded at different times in the Tertiary. The two principal rock types are granodiorite and quartz diorite, but small bodies of quartz monzonite diorite, and alaskite are found in many parts of the area. Contacts between the various rock types may be either abrupt or gradational. All rocks of the Chilliwack batholith are younger than the other rock types except the Skagit and Hannegan Volcanics, which are in part younger than rocks of the batholith. At least two periods of deformation are indicated by the tight folding of the older Custer Gneiss and the greenschist and phyllite of Mount Shuksan and the gentle folding of the younger Chuckanut Formation. At least three periods of faulting occurred, one before and two after the intrusion of the Chilliwack batholith. The two largest fault structures are the Ross Lake fault zone and a long northeast-striking fault that extends for 20 miles from Mount Shuksan down the Chilliwack Valley. The Ross Lake fault zone is pro

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USGS1972

Emergency ground-water supplies in the Seattle-Tacoma urban complex and adjacent areas, Washington

Urban areas that are supplied from surface-water sources are especially vulnerable to major disruption of their water supplies. Such disruption could result from natural disasters such as earthquakes, floods, or landslides or from such other causes as dam failures fallout of radioactive material or other toxic substance from the atmosphere or other toxic substances from the atmosphere or direct introduction (either accidental or deliberate) of any substance that would render the water unfit for use. Prolonged disruption of public water supplies not only causes personal hardships but also endangers health and safety unless suitable alternative emergency supplies can be provided. The degree of hardship and danger generally increases in direct relation to the population density. Ground water because it occurs beneath protective soil and rock materials is less subject to sudden major contamination than are surface-water bodies. For this reason and also because of its widespread availability in the Puget Sound region ground water is especially desireable as a sources of emergency supplies for drinking or other uses requiring water of good quality. In much of the area existing wells would be suitable as safe sources of emergency supplies.

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USGS1972

Low flows and temperatures of streams in the Seattle-Tacoma urban complex and adjacent areas, Washington

Data on the minimum flows of streams and water temperature are necessary for the proper planning and development of the water resources of urban Seattle-Tacoma and adjacent areas. The data on low flows are needed for such purposes as (1) designing and operating municipal and industrial water-supply systems; (2) classifying streams as to their potential for waste disposal; (3) defining the amount of water available for irrigation, for maintaining streamflow as required by law or agreement, and for fish propagation; and (4) designing water-storage facilities. Data on stream temperatures are important to many water users because of the many biological, chemical, and physical properties of water that are dependent on temperature. Agricultural and domestic users as well as municipal, industrial and fishery agencies are concerned with water temperatures. In this report, low-flow data are accompanied by information on seasonal variations in water temperatures at sites selected as representing regional stream-temperature patterns. Because low flows and high water temperatures commonly occur together, they may impose constraints on various uses of the region's streams. The following discussion deals first with low-flow trends in the region, then with stream temperatures, and finally with some of the resulting constraints.

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USGS1972

Test-observation well near Davenport, Washington: description and preliminary results

The 750-foot test-observation well drilled near Davenport, Wash., is one of several drilled to date (1972) to provide information on ground-water conditions in selected areas of the State. The well provides information on aquifer characteristics in this area which are not available from existing deep irrigation wells. The well was drilled by air-rotary methods and penetrates eight aquifer zones (A through H); the upper 75 feet of the well is cased, and the remainder of the hole is open in basalt. Test pumping during drilling showed that the well had specific capacities of (1) 4-8 gpm (gallons per minute) per foot of drawdown when at the 255-foot depth and open to aquifers A through D, (2) 5.6 gpm per foot of drawdown when at the 640-foot depth and open to aquifers A through G, and (3) 76 5 gpm per foot of drawdown when at the full 750-foot depth and open to all eight aquifers. The tests indicate that most of the water available to the well is from the deepest aquifer (zone H). Borehole geophysical logging supplemented the drillers log of the well and provided information on natural gamma radiation, water temperature and resistivity, and borehole diameter. In the completed well each aquifer zone is isolated by cement seals, and piezometer pipes installed to zones B through H allow a basis for defining the vertical hydraulic gradient and ground-water movement in the area. The pipes also permit chemical quality monitoring of water in the various aquifer zones. An additional pipe, installed for providing thermistor access, allows recording of the geothermal gradient in the well which provides a basis for estimating vertical ground-water movement in the area.

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USGS1972

Test observation well near Almira, Washington: description and preliminary results

A 750-foot test-observation well drilled bear Almira, Wash., is one of several drilled to date (1971) in selected areas if the State. The test wells provide information on ground-water conditions where large-scale pumping from wells is rapidly increasing or ids expected to increase, but where data available from existing wells are incomplete and fail to provide adequate guidance for management of the area;s ground-water resources. The upper 60 feet of the Almira well has a 10-inch casing below this depth the well is uncased in basalt. Four major aquifer zones are penetrated by the well. Geophysical logging during drilling provided data on hole diameter, water resistivity (mineralization) and temperature, and natural radiation of the rock units. These data supplemented the driller's log as a basis for final selection of the aquifers to be monitored. Two pumping tests showed that (1) when the well was 546 feet deep and was pumped at a rate of about 510 gpm (gallons per minute) for 9 1/2 hours, the specific capacity was 92 gpm per foot of drawndown; and (2) at the final 750-foot depth, with all four aquifers contributing water and the well being pumped at a rate of 525 gpm for 24 hours, the specific capacity was 96 gpm per foot of drawdown. Water from the well when drilled to its final depth of 750 feet is slightly warmer and somewhat more mineralized than when the well was only 546 feet deep. Four piezometer pipes were installed in the well so that each reflected the head in a specific aquifer zone that is hydraulically isolated from the other aquifer zones by cement seals. The maximum difference in water levels between the uppermost and lowermost aquifers after the zones were isolated was 180 feet; the difference may increase somewhat as the heads in the aquifers continue to adjust after isolation. An access pipe also was provided for an instrument to measure the geothermal gradient. The data that have been obtained from the test-observation well and that which will be available from it in the future are expected to provide invaluable guidance for management of the ground-water resources.

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USGS1972

Test-observation well near Odessa, Washington: description and preliminary results

The test-observation well drilled near Odessa, Wash., provides information on the area's aquifer characteristics which is not otherwise available from existing deep irrigation wells. The information is of value to the State of Washington Department of Ecology in its management decisions in this area where heavy ground-water withdrawals have resulted in increasing annual water-level declines. The 10-inch well is 750 feet deep and penetrates six aquifer zones (A through F) in basalt. The upper 60 feet of the well is cased while the remainder of the hole is open in the basalt. The well was test pumped during drilling and showed specific capacities of (1) 0.65 gpm (gallon per minute) per foot of drawdown when at the 258-foot depth and open to aquifers A and B. (2) 0.62 gpm per foot of drawdown when at the 540-foot depth and open to aquifers A through D, and (3) 22 gpm foot of drawdown when at full 750-foot depth and open to all six aquifers. To supplement the driller's log of the well, borehole geophysical logging provided information on natural gamma radiation, water temperature and resistivity, downhole movement (via flowmeter) of the water, and borehole diameter (via caliper log). Upon completion of the well each aquifer zone was isolated from the others by cement seals, and piezometer pipes were installed to each zone to allow definition of the vertical hydraulic gradient and an estimate of the vertical ground-water movement in the area, along with chemical-quality sampling of the various zones and monitoring of any changes in water quality with time. The initial measurements of water levels showed that the levels generally decrease with aquifer depth, with about 200 feet of head difference existing between the uppermost and lowermost aquifer zones. Another pipe, installed for providing thermometer access, permits recording the geothermal gradient with depth in the well, and provides another basis for estimating vertical ground-water movement in the area. Prior to isolation of the various aquifer zones, the composite water level was recovering from the cessation of pumping at the end of the 1970 irrigation season. On April 6, 1971, this composite water level had begun declining, presumably as a result of p[umping of an irrigation well 1 mile to the northwest, By May 6, after the aquifer zones had been isolated and piezometer pieces installed, water levels in aquifers E and F had declined 11 feet in 15 days, in response to pumping for irrigation in the area. Water levels in aquifers B, C, and D declined somewhat, but mostly in response to the draining of these aquifers to deeper aquifers down the many deep-well boreholes in the area.

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USGS1972

Recent activity of glaciers of Mount Rainier, Washington

Knowing the ages of trees growing on recent moraines at Mount Rainier, Wash., permits the moraines to be dated. Moraines which are ridges of boulders, gravel, sand, and dust deposited at the margins of a glacier, mark former limits of a receding glacier. Knowing past glacial activity aids our understanding of past climatic variations. The report documents the ages of moraines deposited by eight glaciers. Aerial photographs and planimetric maps show areas where detailed field studies were made below seven glaciers. Moraines, past ice positions, and sample areas are plotted on the photographs and maps, along with trails, roads, streams, and landforms, to permit critical areas to be identified in the future. Ground photographs are included so that sample sites and easily accessible moraines can be found along trails. Tables present data about trees sampled in areas near the glaciers of Mount Rainier, Wash. The data in the tables show there are modern moraines of different age around the mountain; some valleys contain only one modern moraiine; others contain as many as nine. The evidence indicates a sequence of modern glacial advances terminating at about the following A.D. dates: 1525, 1550, 1625-60, 1715, 1730-65, 1820-60, 1875, and 1910. Nisqually River valley near Nisqually Glacier contains one moraine formed before A.D. 1842; Tahoma Creek valley near South Tahoma Glacier contains three moraines formed before A.D. 1528; 1843, and 1864; South Puyallup River valley near Tahoma Glacier, six moraines A.D. 1544, 1761, 1841, 1851, 1863, 1898; Puyallup Glacier, one moraine, A.D. 1846; Carbon Glacier, four moraines, 1519, 1763, 1847, 1876; Winthrop Glacier, four moraines, 1655, 1716, 1760, amid 1822; Emmons Glacier, nine moraines, 1596, 1613, 1661, 1738, 1825, 1850, 1865, 1870, 1901; and Ohanapecosh Glacier, three moraines, 1741, 1846, and 1878. Abandoned melt-water and flood channels were identified within moraine complexes below three glaciers, and their time of abandonment was dated. Outwash in three areas was deposited by melt-water of Tahoma Glacier before A.D. 1862, 1873, and 1910, respectively. Flood channels or melt-water channels on either side of Carbon River near Carbon Glacier dated from about 1901 to 1907. Melt-water channels of three different ages cut through Emmons Glacier moraines were dated as being abandoned before 1865, 1871, and 1917, respectively. Although the evidence at Mount Rainier indicates a sequence of glacial advance and retreat and of melt-water flow through different channels at different times, their climatic and hydrologic significance is not yet known.

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USGS1972

Water resources data for Washington, water year 1971; Part 1, Surface water records

Surface-water records for the 1971 water year for Washington, including records of streamflow or reservoir storage at gaging stations, partial-record stations, and miscellaneous sites, are given in this report and their locations shown in figures 1, 2. Records for a few pertinent gaging stations in bordering States also are included. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey under the direction of L. B. Laird, district chief. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Washington.

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USGS1972

Water resources data for Washington, water year 1971; Part 2, Water quality records

Water resources data for the 1971 water year for Washington include records of data for the chemical and physical characteristics of surface water. Data on the quality of surface water (chemical, temperature, and sediment) were collected from designated sampling sites at predetermined intervals such as once daily, weekly, monthly or less frequently. Records are given for sampling stations of which are continuous record stations and are partial-record stations. A few pertinent stations (not included above) in bordering States are also included. The records were collected by the Water Resources Division of the U.S. Geological Survey under the direction of L. B. Laird, district chief. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Washington.

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USGS1972

Distribution of copper and other metals in gully sediments of part of Okanogan County, Washington

A geochemical exploration program aimed at determining regional patterns of metal distribution as well as pinpointing areas likely to contain undiscovered ore deposits was carried out in north-central Okanogan County, Washington. About 1,000 gully and stream sediment samples were collected from a rectangular area of about 800 square miles. The area includes two contiguous, virtually dormant, mining districts that had yielded nearly $1.4 million in gold, silver, lead, copper, and zinc prior to the end of World War I, mostly from quartz lodes.

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USGS1971

Origin of ridge-top depressions by large-scale creep in the Olympic Mountains, Washington

In the high mountain area of the Olympic Mountains, Washington, there are many troughlike depressions on and essentially parallel to ridge tops. The troughs are mostly developed on rocks with strong planar anisotropy: slate, sandstone, and phyllite. Similar features in Europe, Japan, and New Zealand have been variously ascribed to erosion, slow movement along deep-seated shear planes, creep, and tectonic movements. In the Olympics, many depressions parallel structure; one wall is steeply dipping rocks, the other shattered, gently dipping rocks. These depressions seem to be the gaps left between undisturbed steeply dipping rocks and beds or cleavage bent valley-ward by creep. A few troughs may be the result of slow down-slope movement along deep-seated shear planes; this is a favorite explanation of eastern European workers. The Olympic ridge-top depressions testify to the importance of gravity in the degradation of high mountains carved from weak rocks.

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USGS1971

Plate tectonics and magmatic evolution

The validity of the general idea of plate tectonics is accepted; the magmas evolved along the spreading ridges are thought to be largely tholeiitic basalt, although alkalic olivine basalt and ultramafic rocks of several kinds have also been dredged from them. The ultramafics may be residual from the partial melting of pyrolite while the tholeiite was being formed at shallower depths, or they may possibly be fragments of the mantle raised by the injection of sills. Bouvet and Jan Mayen Islands, both on the crest of the Mid-Atlantic Ridge, are largely composed of alkali basalt with very minor differentiates of trachyte and even rhyolite that may be readily accounted for by differentiation at a high level in the volcanic edifice. Iceland, though, has so much granite and rhyolite widely distributed that it seems likely, as suggested by several students, that its basement is sialic. The volcanic islands tend to be more alkalic the farther they are from the ridges; perhaps they rose from deeper sources in areas of low heat flow and are not related to plate margins. If the African Rifts are incipient plate margins, it is noteworthy that the magmas associated with them are wholly different from the tholeiites of the oceanic ridges. They are among the most highly alkaline of any rocks known. The magmatic activity at the subduction zones, where the plates are being destroyed, is very different. There are three varieties of these plate junctions: continental against oceanic, oceanic against oceanic, and continental against continental. In both the junctions involving oceanic crust the material being consumed includes a variable thickness of sediment, underlain by 5 or 6 km of tholeiitic basalt overlying the downgoing mantle. These rocks are much less refractory than the pyrolite of the mantle and must surely compose a large part of material parental to the magmas formed along the subduction zones, the andesites, granodiorites, and granites. There is nowhere the tremendous volume of intermediate rocks that would have had to be formed if these voluminous magmas had been products of crystallization differentiation from a basaltic magma. The presently most active of the continent-continent junctions is along the Himalayas where India is underthrusting the continent of Asia; here there is no evidence of magmatism except along the transcurrent faults at either end of the main range. But there are large volcanic and plutonic masses that have no obvious relation to the plate boundaries active in Mesozoic and Cenozoic time. The Eogene volcanics of the San Juans and the Neogene volcanics of the Yellowstone are more than 1,500 km from any obvious subduction zone, and these regions of magmatic activity seem no more closely related to subduction zones than are the Tertiary igneous rocks of West Texas, the Cretaceous tuffs and plutons of Arkansas, the Cretaceous intrusives of the Monteregian Hills, and the minor Tertiary intrusives of Virginia.

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