Geology topics
Research about Washington
Source-linked reports with geographic coverage including Washington.
Evidence of tectonic stability along the middle Columbia River, Washington, in Quaternary time
Observations of outcrops and Pleistocene-age surfaces along the Columbia River, between Priest Rapids Dam and Richland, Washington, provide evidence for recent tectonic stability that may be significant to planning of earthquake-sensitive engineered structures in the vicinity. Apparent continuity of layering in the Yakima Basalt (Miocene), Ringold Formation (Pliocene), and calcrete capping much of the Ringold Formation (more than 100,000 yrs old), and the absence of appreciable deformation of several large, smooth, late Pleistocene surfaces indicate that there has been little or no deformation along much of this part of the Columbia River since these rocks and surfaces were formed.
Map showing the status of mineral resource potential evaluation of wilderness and roadless areas, Washington
No abstract available.
Historical changes to Lake Washington and route of the Lake Washington Ship Canal, King County, Washington
Lake Washington, in the midst of the greater Seattle metropolitan area of the Puget Sound region (fig. 1), is an exceptional commercial, recreational, and esthetic resource for the region . In the past 130 years, Lake Washington has been changed from a " wild " lake in a wilderness setting to a regulated lake surrounded by a growing metropolis--a transformation that provides an unusual opportunity to study changes to a lake's shoreline and hydrologic characteristics -resulting from urbanization.
Impact of changes in land use on the ground-water system in the Sequim-Dungeness Peninsula, Clallam County, Washington
A digital-computer model was developed to simulate three-dimensional ground-water flow in aquifers underlying the Sequim-Dungeness peninsula, Clallam County, Washington. Analysis using the model shows that leakage from irrigation ditches is the area 's most important source of ground-water recharge. Termination of the irrigation system would lead to lower heads throughout the ground-water system. After 10-20 years of no irrigation, the water-table aquifer would have average drawdowns of about 20 feet and some areas would become completely unsaturated. Several hundred wells could be in danger of going dry. If irrigation were terminated, leakage from the Dungeness River would become the major source of ground-water recharge. As of June 1980, ground-water quality has apparently not been affected in the study area by the use of on-site domestic sewage-disposal systems. The median nitrate-plus-nitrite (as N) concentration in the water-table aquifer was 0.25 milligrams per liter, and the maximum concentration was 2.5 milligrams per liter.
Effects on wildlife from use of endrin in Washington State orchards
No abstract available.
Characterization of dissolved organic materials in surface waters within the blast zone of Mount St Helens, Washington
After the May 18, 1980, eruption of Mount St Helens, the concentration of dissolved organic material in surface waters near the volcano increased significantly as a result of the destruction of the surrounding conifer forest. Low molecular weight organic compounds identified in the blast zone surface waters were derived from pyrolysis of plant and soil organic materials incorporated into pyroclastic flow, mud flow and debris avalanche deposits. A major fraction of the dissolved organic material consisted of high molecular weight, colored, organic acids that are similar in their general properties to aquatic fulvic acids found in more typical surface waters except for greater sulfur contents. The other major fraction of the dissolved organic material consisted of hydrophilic acids, which may include compounds capable of supporting heterotrophic microorganisms, and precursors in the formation of aquatic fulvic acids. The organic chemistry of blast zone surface waters will probably be greatly influenced by the May 18, 1980, eruption for many years.
Irrigation-water quality in the Sulphur Creek basin, Yakima and Benton counties, Washington, April 1976 through March 1977
A water-quality-sampling network was designed for the Sulphur Creek basin to observe the effects of farming practices on irrigation. Sediment and nutrient yield, discharge, and water temperature data were collected during the 1976 irrigation season and the following fall and winter. The suspended-sediment yield of the basin during this period was 2.0 tons per acre of irrigated cropland. Only about 3% of the net outflow of sediment occurred during the nonirrigation season. The yield computed by subbasin ranged from 0.7 to 7 tons per acre, depending mainly on land slope, but a high percentage of orchard land in the subbasins was probably also significant in reducing loads. Nutrient outflows during the study period were 1,180,000 pounds of nitrogen and 120,000 pounds of phosphorous. Nitrate-plus-nitrite represent 70% of the nitrogen outflow in the irrigation season and 84% in the nonirrigation season. The monitoring network was discontinued at the end of the study period, due largely to insufficient farmer participation. Network sensitivity in the control subbasins was inadequate to detect the effects of a planned demonstration program of best management practices. (USGS)
Aeromagnetic map of Mt. St. Helens, Washington: Post May 1980 eruption
No abstract available.
Aeromagnetic map of parts of the Okanogan and Ritzville 1° x 2° quadrangles, Washington
No abstract available.
Principal facts for one hundred-six gravity stations near the Goat Rocks Wilderness Area, Washington
No abstract available.
Intrusive rocks of the Holden and Lucerne quadrangles, Washington— The relation of depth zones, composition, textures, and emplacement of plutons
The core of the northern Cascade Range in Washington consists of Precambrian and upper Paleozoic metamorphic rocks cut by numerous plutons, ranging in age from early Triassic to Miocene. The older plutons have been eroded to catazonal depths, whereas subvolcanic rocks are exposed in the youngest plutons. The Holden and Lucerne quadrangles span a -sizeable and representative part of this core. The oldest of the formations mapped in these quadrangles is the Swakane Biotite Gneiss, which was shown on the quadrangle maps as Cretaceous and older in age. The Swakane has yielded a middle Paleozoic metamorphic age, and also contains evidence of zircon inherited from some parent material more than 1,650 m.y. old. In this report, the Swakane is assigned an early Paleozoic or older age. It consists mostly of biotite gneiss, but interlayered with it are scattered layers and lenses of hornblende schist and gneiss, clinozoisite-epidote gneiss, and quartzite. Thickness of the Swakane is many thousands of meters, and the base is not exposed. The biotite gneiss is probably derived from a pile of siliceous volcanic rocks containing scattered sedimentary beds and basalt flows. Overlying the Swakane is a thick sequence of eugeosynclinal upper Paleozoic rocks metamorphosed to amphibolite grade. The sequence includes quartzite and thin layers of marble, hornblende schist and gneiss, graphitic schist, and smaller amounts of schist and gneiss of widely varying compositions. The layers have been tightly and complexly folded, and, in places, probably had been thrust over the overlying Swakane prior to metamorphism. Youngest of the supracrustal rocks in the area are shale, arkosic sandstone, and conglomerate of the Paleocene Swauk Formation. These rocks are preserved in the Chiwaukum graben, a major structural element of the region. Of uncertain age, but possibly as old as any of the intrusive rocks in the area, are small masses of ultramafic rocks, now almost completely altered to serpentine. These occur either as included irregular masses in later intrusives or as tectonically emplaced lenses in metamorphic rocks. Also of uncertain age but probably much younger, perhaps as young as Eocene, are larger masses of hornblendite and hornblende periodotite that grade into hornblende gabbro. These are exposed on the surface and in the underground workings of the Holden mine. Oldest of the granitoid intrusives are the narrow, nearly concordant Dumbell Mountain plutons, having a radiometric age of about 220 m.y. They consist of gneissic hornblende-quartz diorite and quartz diorite gneiss. Most contacts consist of lit-par-lit zones, but some are gradational or more rarely sharp. The plutons are typically catazonal. Closely resembling the Dumbell Mountain plutons in outcrop appearance, but differing considerably in composition, are the Bearcat Ridge plutons. These consist of gneissic quartz diorite and granodiorite. The Bearcat Ridge plutons are not in contact with older dated plutons, but because their textural and structural characteristics so closely resemble those of the Dumbell Mountain plutons, they are considered to be the same age. Their composition, however, is suggestive of a much younger age. Cutting the Dumbell Mountain plutons is the Leroy Creek pluton, consisting of gneissic biotite-quartz diorite and trondjhemite. The gneissic foliation in the Leroy Creek is characterized by a strong and pervasive swirling. Cutting both the Dumbell Mountain and Leroy Creek plutons are the almost dikelike Seven-fingered Jack plutons. These range in composition from gabbro to quartz diorite; associated with them are contact complexes of highly varied rocks characterized by gabbro and coarse-grained hornblendite. Most of the rocks are gneissic, but some are massive and structureless. Dikes, sills, small stocks, and irregular clots of leucocratic quartz diorite and granodiorite are abundant in the Swakane Biotite Gneiss and are locally abundant in the Seven-fingered Jack and other plutons. Although the leucocratic rocks vary little in appearance or composition, some, particularly those in the Swakane, were formed by metamorphic segregation, whereas the others are probably felsic differentiates of intrusive rocks. The Tenpeak and White Mountain plutons are closely similar and are probably connected at depth. Rocks of the Tenpeak are more varied and range in composition from gabbro to granodiorite; quartz diorite is not only most common in the Tenpeak, but also constitutes, by far, the greatest bulk of the White Mountain pluton. Much of the rock in both plutons is somewhat gneissic, but some is nongneissic. The north end of the White Mountain pluton is bordered by a contact complex similar to those associated with the Seven-fingered Jack and other plutons in the area. Maximum potassium/argon ages determined on hornblende from the Tenpeak are about 90 m.y. Probably somewhat younger than the Tenpeak and White Mountain plutons is the Sulphur Mountain pluton. Only a small part of the pluton extends into the Holden quadrangle, and here the rocks are gneissic granodiorite. The High Pass and Buck Creek plutons are tabular, somewhat silllike masses of granodioritic and quartz dioritic composition. Rocks in the Buck Creek pluton are entirely gneissic, whereas rocks only near the contacts or in the thinner parts of the High Pass are gneissic. In most places, the contacts of both plutons consist of lit-par-lit zones, but numerous dikes of the High Pass are present in the host rocks, especially the Sulphur Mountain pluton. The Riddle Peaks pluton consists of layered and unlayered hornblende gabbro. Inasmuch as the pluton is cut on all sides by later intrusive rocks, its age relative to older plutons is not known, but it is almost certainly pre-Tertiary. Much of the gabbro is rhythmically layered, but some is unlayered or only vaguely layered. In places, thick sheets of unlayered gabbro alternate with equally thick sheets of rhythmically layered gabbro. The rock is mostly fresh and unaltered or recrystallized. No pseudosedimentary structures other than the gravity-stratified rhythmic layers were seen. The Cardinal Peak pluton has a core consisting largely of granodiorite and quartz diorite and a rim of contact complexes containing large amounts of gabbro and coarse-grained hornblendite. The northern part of the intrusive is highly protoclastic throughout and contains numerous spindle- and canoe-shaped masses a third of a meter to several meters across and a few meters to several tens of meters long that are either partly or completely enveloped by rinds of fine-grained protoclastic material. These masses seem to have behaved as roller bearings during intrusion of the partly crystalline magma.