Fast flowing rivers meant that the region has accumulated very little alluvium, except for a rare 400 foot thick deposit in Scott Valley, southwest of Yreka, California. In addition, the McArthur Swamp area could be affected by regional volcanic events originating within the Mt. Ground disturbing activities are prohibited on the Ahjumawi Property by the deed restrictions contained within the Conservation Easement, which will coincide with the property. The soils are moderately to strongly alkaline and have a very high shrink-swell potential (refer to TableVI-1). They have a Capability Class rating of IV and are considered Prime Farmland if drained and irrigated (NRCS, 2000). This ecoregion has one of the most extensive Ponderosa pine forests in the western U.S., occurring in all parts of the ecoregion, from Wenatchee to Mount Lassen. The County Environmental Health Department would act as the monitoring body to ensure compliance with the permit. The geologic information, particularly for the Klamath Mountains, Modoc Plateau, and northern Sierra Nevada, has been updated to reflect the more recent geologic understanding of these complex areas. Roadside Geology of Northern & Central California by David D. Alt and Donald W. Hyndman Only $25.99 Learn about the Geology of California with maps, photos and expert descriptions! Joint surfaces and cavities commonly lined with hematite or montmorillonite clay, secondary silica minerals, zeolites, celadonite, or calcite. These soils are very similar to those discussed for the Bowman Ditch and Ahjumawi Property. However some areas are virtually devoid of vegetation, due to deficient nutrient supplies (NRCS, 2000). "[1], It is a thick accumulation of lava flows and tuff beds, along with many small volcanic cones. The small Conejo field to the east of Camarillo was geologically unusual in that the reservoir rock is fractured volcanic rock from the Miocene. . Age, mostly Oligocene; may include some rocks of early Miocene age. Use the interactive map to zoom smoothly from a national view to state and local perspectives anywhere across the country. Sign in with your username (email address) and password. Per square mile of drainage, the Eel River has the highest suspended sediment load of any river in the US, exceeding the Colorado River and Mississippi River. The plateau is thought to have been formed approximately 25 million years ago. The East Cascades in Washington and northern Oregon resulted from tectonic uplift and subsequent erosion by alpine glaciers and landslides. As a registered user, you can customize maps, save them, and share them with your friends. Geologists have struggled to define its structural geology with complex sequences of deep ocean crust, upper mantle rock and tectonic melanges. Study with Quizlet and memorize flashcards containing terms like 11, Cascade Range, Great Valley, Transverse Range, Peninsular Range, Colorado Desert, Coast Ranges, Sierra Nevadas, Mojave Desert, Modoc Plateau, Klamath Mountains, Basin and Range, Mount Whitney, Sierra Nevadas and more. "Modoc County has an area of 3823 square miles. Five Holocene Faults including the McArthur, Mayfield, Pittville, Hat Creek, and Rocky Ledge faults are all located within 20 miles of the property. The Modoc Plateau Region (Figure MOD-1) encompasses 22,858 km of the volcanic tablelands east of the Cascade and northern Sierra Nevada ranges in Modoc, Lassen, and Siskiyou counties. The Shasta County General Plan contains a Public Safety Element as required by Section 65302(g) of the California Government Code, which requires that General Plans include an element containing identification and appraisal of seismic and geologic hazards. The ditch was originally channeled out to increase flows to the Tule River for the Pit River Hydroelectric Project. May include some rocks of middle Miocene age in the area west and northwest of Lakeview. As shown, may include some rocks older than Oligocene, correlative with upper parts of unit Tea. Examples include the Silverado Formation with 1400 feet of Paleocene terrestrial sedimentary rock in the Santa Anas or the Eocene Poway Formation near San Diego. Soils located on the Ahjumawi Property consist of the Pastolla muck, 0 to 1 percent slopes, which are similar to those located along the Bowman Ditch, except that it is not artificially drained (NRCS, 2000). Britton Silt Loams, 30 to 50 percent slopes soils are characterized as being relatively shallow (10 to 20inches), and well drained with moderately slow permeability. Rockhounding. Contribute to chinapedia/wikipedia.en development by creating an account on GitHub. They have a Capability Class rating of II and are classified as Prime Farmland when properly drained and irrigated (NRCS, 2000). Shield volcanos. The rocks likely formed much further away from the Sierras and were relocated by the dramatic movements of faults. Thick sequences of marine rocks from the Late Cretaceous through the Paleocene and Eocene are common in the mountains and on San Miguel Island. They are shallow, well drained cobbly loams of moderate permeability and are neutral to mildly acidic. Flow in and out of the estuary has been controlled with a man-made structure since heavy silting in 1915. The Fall River Valley and McArthur-Burney Fall Memorial State Park are located at the southern end of the Cascade Range within the Modoc Plateau Geomorphic province. There are also several herds of wild horses on the plateau. Includes Shumuray Ranch Basalt and Antelope Flat Basalt of Kittleman and others (1965), Grassy Mountain Basalt of Corcoran and others (1962), Drinkwater Basalt of Bowen and others (1963), basalt formerly assigned to Danforth Formation by Piper and others (1939) (see Walker, 1979), Hayes Butte Basalt of Hampton (1964), Pliocene and upper Miocene basalt flows capping and interstratified with the Madras (or Deschutes) Formation, and basalt flows interstratified in the Dalles Formation of Newcomb (1966; 1969). According to the Soil Survey for the Intermountain Area of California, ten soil mapping units have been delineated within the vicinity of the McArthur Swamp Property (see TableVI-1). The movement of the San Andreas Fault and Garlock Fault helped to induce arid conditions during the Cenozoic. Policy SG-f - Shasta County shall pursue preparation of development standards based on topography and soil erosion potential in revising its land capability standards pursuant to Policy CO-h. Policy SG-g - Shasta County should comply with the requirements of the Seismic Hazards Mapping Act, when the Seismic Hazards Maps for the County are completed and made available by the State Geologist. They have a low erosion hazard from water when bare and a moderate hazard from wind erosion. In the early Cenozoic, widespread erosion of crystalline rocks inland produced huge quantities of sediment which deposited on the Cretaceous rocks of the Peninsular Ranges. [2] The plateau is thought to have been formed approximately 25 million years ago as a southern extension of the Columbia Plateau flood basalts. Examples of rock formations in the Franciscan subduction complex include the Calera limestone east of the San Andreas fault or the Laytonville limestone which extends north of San Francisco to Eureka. Potassium-argon ages on rocks in unit from southeast Oregon range from about 13 to 16 Ma; lenses of interbedded tuffaceous sedimentary rocks locally contain a Miocene (Barstovian) vertebrate fauna, Plugs and domal complexes of rhyolitic, rhyodacitic, and dacitic composition; includes related near-vent flows, flow breccia, and deposits of obsidian, perlite, and pumice. The McArthur fault is mapped as trending in a northwesterly direction about three miles northeast of the site between Big Lake and Horr Pond (CDMG, 1994). Occasional lakes, marshes, and sluggishly owing streams meander across the plateau. Serious flooding in 1862 created a three mile wide lake in the Santa Ana River, while serious flooding in 1938 inundated the San Fernando Valley and parts of the Los Angeles coastal plain, damaging 100 bridges and killing 43 people. The area extends north to the Oregon border and south to include the Skedaddle Mountains and the Honey Lake Basin. These mapped faults include the McArthur, Mayfield, Pittville, Hat Creek, and Rocky Ledge faults; whereby the McArthur fault trends northwesterly through the site between Big Lake and Horr Pond (CDMG, 1994). The plateau consists of a thick accumulation of lava flows and tuff beds along with many small volcanic cones. Non-seismic hazards addressed in the document include volcanoes, erosion, and expansive soils. The subsurface is well known from oil wells and oil fields are bounded in the east by the Kern Front fault. California Geological Survey External Resources This product is available, please note the publication series and number, and then contact: California Geological Survey Publications 801 K Street MS 14-34 Sacramento, CA 95814-3532 Phone: (916) 327-1850 Fax: (916) 327-1853 Email: cgspubs@conservation.ca.gov These include the Britton Silt Loam, 30 to 50 percent slopes and Burney-Arkright Complex, two to nine percent slopes mapping units. Eruptions relatively quiet, but spectacular. Some Great Valley rocks are exposed in the Coastal Ranges as well, like the Jurassic Knoxville Formation shale. Most precipitation accumulates from November through April. As a result, the applicant will be required to obtain a grading permit from the Shasta County Environmental Health Department consistent with the Shasta County Grading Ordinance. The rugged terrain of the Modoc Plateau played an important role in the Modoc War. It is drained by the Pit River, which ultimately reaches Shasta Lake and the Sacramento River. [7], The Klamath Mountains formed as small island arc terranes accreted against the coast of North America before and during the Devonian and overlain by newer rocks, deposited from the Cretaceous to modern times. Abstract. In some places, ophiolite sequences preserve remnant oceanic crust rock on land, while other parts of the range are intruded with ultrabasic igneous rocks that have serpentinized to peridotite. Includes Touchet Beds of Flint (1938), deposits of valley terraces of Newcomb (1965), and, in southeast Oregon, basin-filling deposits that incorporate Mazama ash deposits (Qma, Qmp) in the youngest layers, Sand, gravel, and silt forming flood plains and filling channels of present streams. In the Shoo Fly complex, the Bullpen Lake sequence has bedded cherts and cooled pillow lava that closely resembles rocks found on flat-topped offshore volcanic guyots, suggesting a deep-sea origin for the base of the Sierras sometime before the Devonian. Site is located on private property in Modoc County, California, approximately 10 kilometers from the Oregon border and 20 kilometers from the Nevada border. Each of the proposed transfer properties are located within a seismically active region and could experience significant groundshaking and/or earthquake induced landslides resulting from displacement along one of the following Holocene Faults including the, McArthur, Mayfield, Pittville, Hat Creek, and Rocky Ledge faults. Unique geology in the region formed bastnaesite mined at the Mountain Pass rare earth mine. The Modoc Plateau is part of the larger Columbia Plateau which extends into eastern Oregon and Washington, southern Idaho, northern Nevada and western Wyoming. An official website of the United States government. Condado de Modoc, California, Estados Unidos The northeastern-most county in California with a total area of 4,203.37 square miles, but with a population under 10,000. The purpose of the Alquist-Priolo Act is to regulate development on or near active fault traces to reduce the hazard of fault rupture and to prohibit the location of most structures for human occupancy across these traces. Areas in the central portion of the northern half of the property contain the Henhill Silt Loam, partially drained, 0 to 2 percent slopes mapping unit. Unit is present in all counties. Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene. Over 40 different oil and gas fields are found in association with the Transverse Ranges and their surrounding basins. A thick sequence of mostly terrestrial sedimentary rocks including the Rosario, Ladd, Trabuco and Williams formations is exposed on the western slope of the Santa Ana Mountains and Santa Ana Canyon, stretching southward to Camp Pendleton, San Onofre, and smaller exposures in Encinitas, Leucadia, Point Loma and La Jolla. Additionally, when polygons have been edited and changed to alluvium, Qal was used as the general value; hence it now is present in all counties. The combination of these processes and volcanic activity created rugged ridges extending southeast to east from the Cascade crest. Areas along the northeastern shores of Big Lake are mapped as Recent Modoc basalt flows (CDMG, 1968). In the northeastern corner of California, lies a massive volcanic plain known as the Modoc Plateau. The Josephine ophiolite forms the basement of the western Klamath Mountains, with extensive peridotite from the boundary between the oceanic crust and the mantle, as well as chromite and nickel deposits. For those that did not, or used other generalized terms for Quaternary rocks, the unit Qal has been used for the general undivided alluvium. Examples of filled basins included the Los Angeles Basin, the Eel River Basin around Eureka or the 50,000 foot thick sedimentary sequences of the Ventura Basin. The Western Jurassic Plate stretches for 220 miles on the western edge of the mountains. The Modoc Plateau is an undulating expanse of Miocene to Holocene basalt law flows at the southwest edge of the Columbia Plateau, covering 10,000 square miles. These soils formed in basins from fine-textured alluvium from extrusive and basic igneous rock. From the oldest to the youngest, Georgia's provinces are the Piedmont, Blue Ridge, Valley and Ridge, Appalachian Plateau, and the Coastal Plain. To determine the nature of the differences between northern and southern Arizona, geologists could: map the geology in detail, take seismic profiles, study drill core, and reconstruct the geologic history between each province. Nearly 1,000,000 acres (400,000 ha) of the Modoc National Forest are on the plateau between the Medicine Lake Highlands in the west and the Warner Mountains in the east. and late Miocene in age (see Fiebelkorn and others, 1983), flows of Deer Butte Formation of Kittleman and others (1967), and extensive unnamed flow sequences in the Basin-Range and Owyhee Upland Provinces of southern Lake, Harney, and Malheur Counties that are younger than Steens Basalt, dated at about 15 Ma (Baksi and others, 1967) and the Owyhee Basalt, dated at about 14 Ma (Bottomley and York, 1976; see also Fiebelkorn and others, 1983), and older than 7 or 8 Ma. Contribute to chinapedia/wikipedia.en development by creating an account on GitHub. The Santa Ynez Mountains extend up the coast of Santa Barbara County and contain Franciscan basement rocks (also referred to as the Franciscan basement complex) like the Coast Ranges. The Southern unglaciated Allegheny Plateau is a maturely dissected plateau characterized by high hills, sharp ridges and narrow valleys. The Santa Monica Mountains and the Channel Islands are different than the mountains to the north because they have granitic and metamorphic basement rocks more like the Sierra Nevada. [10], At the edge of the Los Angeles coastal plain and just west of the San Joaquin Hills, Newport Bay is a major hub of boating. Upper Klamath Lake is Oregons largest lake and is the biggest remnant of this wetland system. Its main production ran from 1892 to the 1940s, supplying lubricating oil for other refineries. One potassium-argon age of about 28 Ma on porphyritic hornblende andesite from Sheep Creek, southwest corner of Union County, indicates in part coeval with unit Tsf. This produced major crustal stretching, volcanism and displacement of up to 125 miles. ADVERTISEMENT Policy SG-e - When soil tests reveal the presence of expansive soils, engineering design measures designed to eliminate or mitigate their impacts shall be employed. These different regions are called geological provinces.
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