Geology topics
Research about Washington
Source-linked reports with geographic coverage including Washington.
Reconnaissance geochemical survey of gully and stream sediments, and geologic summary, in part of the Okanogan Range, Okanogan County, Washington
A reconnaissance geochemical stream-sediment sampling survey was conducted in a 1,150-km 2 (440 mi 2 ) area in the central part of the Okanogan Range, adjacent on the west to a 2,000-km 2 (800 mi 2 ) area previously studied. About 75 percent of the bedrock is composed of a mosaic of elongate northwest-trending Mesozoic plutons, the average composition of which is probably granodiorite. These intrude a highly recrystallized eugeosynclinal assemblage of Paleozoic and Mesozoic age that makes up about 15 percent of the area. The remaining 10 percent consists of andesite and dacite flows and flow breccias of Tertiary age that unconformably overlie the older rocks. The entire area is irregularly mantled by glacial drift.
Allochthonous Jurassic ophiolite in northwest Washington
Fragments of Jurassic ophiolite having U-Pb zircon ages narrowly grouped at 160 to 170 m.y. are widespread over parts of northwest Washington. The Haystack thrust fault is inferred to mark the base of the ophiolite in the San Juan Islands and adjacent Cascade foothills; other bodies of mafic and ultramafic rock in the western Cascades may be klippen of the Haystack thrust plate. The Haystack thrust fault is probably the structurally highest and possibly most extensive thrust yet recognized within a family of Late Cretaceous thrust faults in northwest Washington. The ophiolite and its time of emplacement (bracketed between about 100 and 88 m.y.) suggest a similarity with the Coast Range thrust of California which thrust Upper Jurassic ophiolite and the Great Valley sedimentary sequence over the Franciscan assemblage. However, relations in the Cascades are complicated by the extraordinarily diverse character of lower plate rocks, of which very few resemble the Franciscan. We conclude that an original subduction system was modified by later tectonic activity so that a variety of terranes was juxtaposed as a family of rootless thrusts, with the ophiolite forming, at least in some areas, the uppermost structural unit. Perhaps the emplacement of Wrangellia, an allochthonous microcontinent west of the San Juan Islands, caused the thrusting.
Channelization and livestock impacts on salmonid habitat and biomass in western Washington
We examined salmonid habitat and biomasses in 50–70‐m pairs of altered and control sections of small (discharges less than 0.3 m 3 second −1 ) streams around Puget Sound in western Washington in 1978–1979. Altered sections had been channelized or used by livestock. Channelization significantly reduced overhead cover, sinuosity, wetted area, and woody bank cover while increasing bank grasses. Total habitat area declined in altered areas. These impacts most damaged the quality of habitat for cutthroat trout (Salmo clarki) over 70 mm in length. Biomass of coho salmon (Oncorhynchus kisutch) did not decline significantly in altered sections except in areas severely damaged. Zero‐age trout (cutthroat and steelhead, Salmo gairdneri) suffered no loss of habitat quality, although larger trout did, except in areas of severe physical impact. Short‐term effects of machinery operation in the one stream for which data were obtained included biomass depletions of all salmonid species and size classes. Channelization and livestock use appeared to reduce quality of winter habitat for salmonids. In altered sections with stable bottoms, no recent damage history, relatively little silt and sand, and adequate riffle areas, the reduction in overhead cover appeared to lead to higher standing crops of salmonids, suggesting that fish production in many streams of the Puget Sound area may be light‐limited.
Multiple ice flow directions during the Fraser Glaciation in the lower Skagit River drainage, northern Cascade Range, Washington
Stratigraphic mapping and pebble-count data suggest that ice flowed in three different directions in the lower Skagit drainage of the northern Cascade Range during the Fraser Glaciation (∼ 10K to 20K BP). Glacier reconstructions suggest that till exposed at one site in the lower Skagit Valley was deposited by a Baker Valley glacier that flowed westward down the Skagit Valley during the early part of the Fraser Glaciation (Evans Creek Stade). Stratigraphic relations show that the Cordilleran Ice Sheet subsequently advanced up the Skagit Valley and into the Baker Valley during the Vashon Stade. Flow-direction indicators, as well as clast compositional variations in till and recessional deposits of Vashon age, indicate that this upvalley, eastward-advancing glacier was later overwhelmed by southeast-flowing ice of the Cordilleran Ice Sheet which entered the Baker Valley across the valley divide to the northwest.
Mount St. Helens volcanic-ash fall in the Bull Run watershed, Oregon, March-June 1980
During several periods of volcanic-ash eruption at Mount St. Helens, Wash., (March 30, May 25-26, May 30-June 2, and June 12-13, 1980) strong winds from the north occurred at high altitudes. As a result, the volcanic ash fell some 50 miles to the south in the Bull Run watershed, the principal water-supply source for the metropolitan area of Portland, Oreg. Water samples collected from three stream sites within the watershed were compared with samples collected during the same season in previous years. No detectable changes were noted in chemical characteristics. Precipitation samples collected immediately after the June 12-13 ash fall ranged in specific conductance from 20 to 41 micromhos per centimeter at 25C and in pH from 4.0 to 4.3 pH units. Stream samples collected during the May-June period ranged in specific conductance from 18 to 28 micromhos per centimeter at 25C and in pH from 6.7 to 7.5 pH units. Volcanic-ash samples were collected and analyzed for particle size, chemical composition, and weight. Significant differences in particle size of ash were found in samples from two separate eruptions. (USGS)
Ground-water hydrology of the Sagebrush Flat area as related to the discharge of Rattlesnake Springs, Grant and Douglas counties, Washington
In 1978, the U.S. Geological Survey, in cooperation with the State of Washington Department of Ecology, investigated the hydrology of the Sagebrush Flat area as it relates to Rattlesnake Springs. Rattlesnake Springs and all known wells on Sagebrush Flat obtain water from basalt aquifers. The wells tap aquifers at or below the altitude of the spring discharge. Water levels in some wells on Sagebrush Flat, and in a well 27 miles to the northeast in an area of no ground-water development, show slight fluctuations that may correspond to annual variations in precipitation. However, hydrographs of most wells on Sagebrush Flat show water-level declines and rises that correspond with the beginning and end of the pumping season. The discharge of Rattlesnake Springs started to decrease at about the beginning of the 1978 pumping season and did not start to increase until after most pumping was stopped. The water level in deep aquifers beneath Sagebrush Flat is at a lower altitude than in shallow aquifers, and water moves down well boreholes from shallow aquifers to deeper aquifers. This downward movement of water diverts ground water that is moving toward natural discharge points such as Rattlesnake Springs, thereby decreasing the discharge at these points.
Ground-water availability on the Kitsap Peninsula, Washington
Unconsolidated deposits on the Kitsap peninsula are of glacial and interglacial origin. These deposits were divided into three units on the basis of their lithology and hydraulic properties. Two of the three units are composed of layers of sand and gravel alternating with layers of silt and clay. The third unit consists of silt and clay and in most places separates the other two units. The thickness of the upper unit ranges from 200 to 600 feet and the middle unit from 10 to 260 feet. The thickness of the lower unit is believed to range from 2,000 to 3,000 feet. The water-bearing strata in the upper unit are fairly continuous and average 15 feet in thickness. The lower water-bearing strata probably are not as continuous as those in the upper unit, but they yield larger quantities of water to wells. The silt-and-clay unit averages 70 feet in thickness, occurs generally near sea level, and is not known to contain any major water-bearing deposits. The average annual ground-water recharge to streams on the Kitsap peninsula was estimated to be 17 times the 1975 annual ground-water pumpage for the peninsula. Some, hut an unknown amount, of this water is available for increased withdrawal by wells. Increased withdrawals cause decreased streamflow, declining water levels, and increased seawater contamination. There appears to be no widespread seawater contamination of wells in the study area. Local areas where chloride concentrations in well water exceed 25 milligrams per liter are the southern part of the Longbranch peninsula, Horsehead Bay, Point Evans, Sinclair Inlet, Eagle Harbor, Fletcher Bay, the north end of Bainbridge Island, and the north tip of the Kitsap peninsula.
Geologic field trip guide for Cenozoic stratigraphy of southwestern Washington
This summary of southwestern Washington stratigraphy describes the principal Tertiary formations comprising the Cenozoic sequences. A field trip road log provides directions for access to type and/or reference localities for each formation discussed. Tertiary rocks of southwestern Washington, measuring nearly 13,000 feet in thickness, are mapped as thirteen formational units. These units crop out within several structural basins formed along the tectonically active Pacific margin of the North American Plate. Thick Quaternary sands and gravels of glacial and fluvial origin and a heavy vegetational cover restrict exposures to stream and river banks, highway, road and railroad cuts, and occasional steep hillsides. The Tertiary strata are predominantly marine sedimentary rocks with interbedded volcanics and eastwardly increasing amounts of nonmarine strata. Age equivalent and genetically similar sequences occur throughout the Coast Ranges of western Oregon and Washington.
Preliminary map of offshore geology in the Protection Island-Point Partridge area, northern Puget Sound, Washington
No abstract available.
Evaluation of the Wilkeson-Carbonado coal field, Pierce County, Washington, for hydraulic coal mining
No abstract available.
Aeromagnetic map of the central Grays Harbor County area, Washington
No abstract available.
Makah Formation — A deep-marginal-basin sequence of late Eocene and Oligocene age in the northwestern Olympic Peninsula, Washington
The Makah Formation of the Twin River Group crops out in a northwest-trending linear belt in the northwesternmost part of the Olympic Peninsula, Wash. This marine sequence consists of 2800 meters of predominantly thin-bedded siltstone and sandstone that encloses six distinctive newly named members--four thick-bedded amalgamated turbidite sandstone members, an olistostromal shallow-water marine sandstone and conglomerate member, and a thin-bedded water-laid tuff member. A local unconformity of submarine origin occurs within the lower part of the Makah Formation except in the central part of the study area, where it forms the contact between the older Hoko River Formation and the Makah. Foraminiferal faunas indicate that the Makah Formation ranges in age from late Eocene (late Narizian) to late Oligocene (Zemorrian) and was deposited in a predominantly lower to middle bathyal environment. The Makah Formation is part of a deep-marginalbasin facies that crops out in the western part of the Olympic Peninsula, in southwesternmost Washington and coastal embayments in northwestern Oregon, and along the central part of the coast of western Vancouver Island. On the basis of limited subsurface data from exploratory wells, correlative deep-marginal-basin deposits underlie the inner continental shelf of Oregon and the continental shelf (Tofino basin) along the southwestern side of Vancouver Island. Directional structures in the Makah Formation indicate that the predominantly lithic arkosic sandstone that forms the turbidite packets was derived from the northwest. A possible source of the clastic material is the dioritic, granitic, and volcanic terranes in the vicinity of the Hesquiat Peninsula and Barkley Sound on the west coast of Vancouver Island. Vertical and lateral variations of turbidite facies suggest that the four packets of sandstone were formed as depositional lobes on an outer submarine fan. The thin-bedded strata between the turbidite packets have characteristics of basin-plain and outer-fan fringe deposits.
Water resources data for Washington, water year 1979, Vol. 1 - Western Washington
Water resources data for the 1979 water year for Washington consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground-wells. This report, in two volumes, contains records for water discharge at 237 gaging stations; stage only at 5 gaging stations; stage and contents at 43 lakes and reservoirs; water quality at 135 gaging stations (including 6 lakes and reservoirs) and 100 wells; and water levels at 164 observation wells. Also included are data for 88 crest-stage and 89 water-quality partial-record stations. Locations of sites in this volume are on figures 4, 5, 6, and 22. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements and analyses. These data represent that part of the national Water Data system operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Washington.
Water resources data for Washington, water year 1979: Vol. 2 - Eastern Washington
Water resources data for the 1979 water year for Washington consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground-water wells. This report, in two volumes, contains records for water discharge at 237 gaging stations; stage only at 5 gaging stations; stage and contents at 43 lakes and reservoirs; water quality at 135 gaging stations (including 6 lakes and reservoirs) and 100 wells; and water levels at 164 observation wells. Also included are data for 88 crest-stage and 89 water-quality partial-record stations. Locations of sites in this volume are on figures 4, 5, and 19. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements and analyses. These data represent that part of the national Water Data system operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Washington.
Water resources of the Port Gamble Indian Reservation, Washington
This report provides information on the water resources of the Port Gamble Indian Reservation, Washington, including ground- and surface-water quality and quantity data and interpretations of the data. This information was gathered to provide a base for management and protection of the water resources of the reservation. Ground water in the study area generally occurs in two aquifers. A shallow aquifer in weathered till (or fine sand and gravel) generally yields only enough water to wells to supply one or two households, and a lower artesian-aquifer system of sand and gravel layers near or below sea level produces higher yields--more than 65 gallons per minute to at least one well. Future supplies of ground water probably can be withdrawn from the lower artesian-aquifer system almost anywhere beneath the reservation. The estimated natural discharge of ground water from the lower artesian-aquifer system to Hood Canal and Port Gamble (bay) is about 42,000 cubic feet per day, or an average of about 220 gallons per minute. Of this amount, it is estimated that about 90 gallons per minute can be economically withdrawn, probably without greatly increasing chances of seawater intrusion. One well in the area taps a still deeper artesian aquifer that is otherwise unexplored. This aquifer, 75 to 80 feet or more below sea level, could possibly supply additional ground water for future use. Ground-water quality is good, but the water is moderately hard and has moderately high iron concentrations. Chloride analyses indicate that in 1977 there was no seawater intrusion into the lower aquifer tapped by wells in the community of Little Boston.
Water resources of the Makah Indian Reservation, Washington
The residents of the Makah Indian Reservation depend on the streams of the area for their fisheries and domestic water supply. The temporal distribution of streamflow in the study area is closely related to the amount and distribution of rainfall. In a year of average precipitation about three-quarters of the streamflow can be expected to occur during the 6-month period October-March. Although the chemical quality of water in streamsis suitable for domestic purposes, State water-quality standards are not met by most streams at certain times of the year because of excessive fecal-coliform bacteria and turbidity levels. Nutrient concentrations in the Waatch and Sail Rivers are sometimes high enough to cause nuisance-plant growth. Suspended-sediment concentrations were low in all streams sampled. Ground water is known to occur only in sand and gravel layers that underlie the lowlands of the reservation. Individual wells are capable of yielding as much as 90 gallons per minute. Several wells in the Neah Bay area have been abandoned because of inferior water quality. In coastal areas, an individual domestic well on each 10-acre allotment should provide sufficient water for the occupants without danger of seawater intrusion.