It also interfingers with up 23,000 feet of volcanic rocks in the Rogue Formation. The Shasta County General Plan provides the following policies for properties outside of the FERCs jurisdiction as they relate to seismic and geologic hazards: Policy SG-c - Shasta County shall coordinate with state and federal agencies monitoring volcanic activity and shall periodically review and update the Shasta County Emergency Plan with respect to volcanic hazards. Geologic guide to the Modoc Plateau and the Warner Mountains : annual field trip guidebook of the Geological Society of Sacramento, 1980. The 7.6 magnitude 1952 Kern County earthquake was one of the most powerful in California in the 20th century. There is a dramatic moisture gradient across the ecoregion as the precipitation diminishes from the cold, wet Cascade crest (up to 120 inches of precipitation per year) to the warm, dry eastern border with the Columbia Plateau and Great Basin (less than 20 inches per year). The volcano is positioned at a kink where northwest-trending faults entering the volcano from the south turn to the northeast, and then back to northwest. doi: 10.4095/223767. The province covers an area of 337,000 km2 (130,000 mi2) within western Colorado, northwestern New Mexico, southern and eastern Utah . The ditch was originally channeled out to increase flows to the Tule River for the Pit River Hydroelectric Project. Source: US geologic names lexicon (USGS Bull. Typical rock formations in the area include volcanic breccia, mud and ash flows, lava flows, lacustrine (lake) deposits, and cinder cone pyroclastic rocks. The basement rocks of the Sierra Nevada date to the Paleozoic and include rocks in the Shoo Fly complex and Grizzly Formation. This area lies along the northwestern-most flank of the Sierra Nevada Geomorphic Province. The Ahjumawi Property is located immediately adjacent to the southeast of the Bowman Ditch and therefore the subsurface is comprised of similar alluvial sediments and water-lain ash deposits. The tribes manage tribally-owned lands on reservations and are also involved in monitoring and research activities on ceded lands. Locally porphyritic with phenocrysts of alkali feldspar, plagioclase, and minor augite, ferro-hedenbergite, hornblende, hypersthene, or biotite. Tertiary pyroclastic and volcanic mudflow deposits. [4] and Modoc Cypress (Cupressus bakeri).[5]. Links to Completed Ecoregional Assessments. Includes older alluvium and related deposits of Piper (1942), Willamette Silt (Allison, 1953; Wells and Peck, 1961), alluvial silt, sand, and gravel that form terrace deposits of Wells and others (1983), and Gresham and Estacada Formations of Trimble (1963). With much of the bays only 30 feet deep, human activity has accelerated erosion and filling due to historical hydraulic mining and farming. 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. Tribes are active participants in discussions about natural resources management and conservation activities within their usual and accustomed areas. The soils are moderately to strongly alkaline and have a very high shrink-swell potential (refer to TableVI-1). The southern portion of the McArthur Swamp property is comprised of numerous soil mapping units, which include the Cupvar, Whipp, Pittville, Dugan, and Graven soil series. Around Shasta Reservoir are other copper and zinc deposits in the Triassic-age Bully Hill rhyolite. Much of the north-eastern part of the state is actively stretching apart, creating numerous faults, all capable of producing earthquakes. The San Andreas Fault became perhaps most active after the Miocene, potentially resulting in up to 350 miles of offset in some locations.[2][3]. Some counties divided the alluvium into younger and older units, and some did not. The Poway Formation has rounded metavolcanic pebbles with no known source nearby, suggesting an original source somewhere in Sonora before a major offset to the north by faults. The oldest rocks are found in the San Jacinto and Santa Rosa mountains, with schist and gneiss that may be up to 22,000 feet thick. Further, DPR is bound by its General Plan with respect to Burney Falls and must conduct a CEQA review for any activities which deviate from the approved plan. Includes Picture Rock Basalt of Hampton (1964), radiometrically dated by potassium-argon methods as middle(?) Medicine Lake volcano is located at the intersection of major tectonic features including the northwestern extension of the Walker Lane fault zone. However, the Greenhorn Fault system is more active to the south, extending to the Tehachapi Mountains and causing more plateau-like landforms. Basalt flows, plugs and dikes, some olivine basalt, and andesite and latitic rocks. It is drained by the Pit River, which ultimately reaches Shasta Lake and the Sacramento River. The New Almaden mine opened in 1824, ultimately extending 2,450 feet below ground. Official websites use .gov The Western Paleozoic and Triassic Plate is the most common unit of the Klamath Mountains and is up to 50 miles wide at the Oregon state line. These different regions are called geological provinces. Three remaining mapping units are located in a band along the southern portion of the property and include the Dugan-Graven Complex, Flooded, 0 to 5 percent slopes, Dugan-Graven Complex, 0 to 5percent slopes, and the Pittville Sandy Loam, 0 to 5 percent slopes occupy this area. The low shield shape, central caldera, and dominance ofmaficlavas are similar to Newberry Volcano of central Oregon, also located in anextensionaltectonicenvironment east of the Cascade arc axis. Andesite and dacite typically have plagioclase, hornblende, and clinopyroxene phenocrysts; some flows aphyric. Seismic hazards addressed by this element include surface faulting, ground shaking, and ground failure. It is in northeastern California about 50 km (31 mi) south of Klamath Falls, Oregon. Comments: Columbia Plateau. Kokanee (Oncorhynchus nerka) can be found in lakes in the northern and central portions of this ecoregion in Washington. In the late 20th century, enough gold was found in association with the mercury, arsenic, tungsten and thallium to open the McLaughlin mine in the Mayacmas Mountains around Knoxville. However, a bulge in the bay's sand spit records offshore presence of the Newport submarine canyon. Nearly 1,000,000 acres (400,000ha) of the Modoc National Forest are on the plateau between the Medicine Lake Highlands in the west and the Warner Mountains in the east. Lava Beds National Monument is on the Modoc Plateau in Modoc and Siskiyou Counties. Geology - 156 pages. Shrub-steppe vegetation composed of big sagebrush (Artemesia tridentata) or antelope bitterbrush (Purshia tridentata) and native bunchgrasses occurs along the foothills and higher south-facing slopes. 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). Shasta, Lassen Peak, or Medicine Lake volcanic centers, all of which have experienced activity within the last 500 years (CDMG, 1994). The Lava Flows-Gassaway Complex, 2 to 15 percent slopes map unit is found along the northeastern shoreline of Big Lake at the northeastern edge of the site. The only significant difference is attributed to the continued maintenance of the McArthur Levee, which has kept these soils drained and suitable for grazing. Virtually all of the islands in the bay are man-made from dredged sediments. It is mostly interchangeable with Qal, except that it implies some specifically younger Quaternary deposits. The Fall River Watershed lies within the volcanic terrain of the Modoc Plateau geomorphic province, and is the largest sub-drainage in the middle reach of the Pit River. Major uplift was going on in Pleistocene, with some marine terraces raised 1000 feet. Modoc National Forest 800 West 12th Street Alturas, CA 96101 (530) 233-5811 Warner Mountain Ranger District PO Box 220 Cedarville, CA 96104 (530) 279-6116 Camping Warren Peak and Patterson Lake The nearest campground is available at Pepperdine Camp, near the trailhead. The Warner Basalt is the most common rock in the plateau, bordered by the Surprise Valley fault zone that first became active in the Miocene 15 million years ago. The small Conejo field to the east of Camarillo was geologically unusual in that the reservoir rock is fractured volcanic rock from the Miocene. Better run fast! The McArthur Swamp and the Glenburn Dredge Site are located within the same regional geographical area and geomorphic province as the McArthur-Burney Falls Memorial Park. This property could potentially be subjected to ground motion from displacement along any of these local and regional faults. This act requires the State Geologist to delineate various seismic hazard zones and requires cities, counties, and other local permitting agencies to regulate certain development projects within these zones. Most of these wetlands have been drained and converted to agriculture. Plateau in the northeast corner of California, United States, List of plants on the Modoc National Forest, California Geologic Provinces, Note 36, page 2, https://en.wikipedia.org/w/index.php?title=Modoc_Plateau&oldid=1106243134, California placenames of Native American origin, Wikipedia articles needing clarification from May 2016, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 23 August 2022, at 20:13. In some areas, decades of fire suppression have resulted in large areas of dense, fire-prone forest. The mountains are drained by the Santa Margarita, San Luis Rey, San Diego and San Dieguito rivers, while San Felipe Creek in the east drains into the Salton Sea. See table of contents below. Simultaneously island arcs and small sections of continental crust rafted onto the edge of North America, building out the continent. They are associated with the Whipp-Cupvar Complex, slightly saline, 0 to 2percent slopes mapping unit which occupies a flanking position to the south. Also includes minor rhyolite and dacite flows and domes. Therefore, it is located within a zone of crustal weakness that likely provides a preferred pathway formagmasto reach the surface; the regional fault trends are the primary control onventlocations. 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. May include some rocks of middle Miocene age in the area west and northwest of Lakeview. The Peninsular Ranges are a group of mountain ranges that extend 900 miles (1,400km) from the Los Angeles basin and Transverse Ranges southward the entire length of Baja California. The monument, established in 1925, includes the sites of many important battles of the Modoc Indian War of 1872-73. A machinist leased the property and used windmills to get small remaining amounts of oil out. Precipitation also changes significantly from north to south, with annual rainfall below 12 inches per year in portions of the Modoc Plateau in California. 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. Additionally, borate deposited during arid conditions, with mining after 1926. The East Cascades in Washington and northern Oregon resulted from tectonic uplift and subsequent erosion by alpine glaciers and landslides. Rhyolitic to dacitic varicolored bedded tuff, lapilli tuff, and fine- to medium-grained tuffaceous sedimentary rocks with interstratified welded and nonwelded ash-flow tuff and interbedded basalt and andesite flows. The eastern portion of the property is underlain by Plio-Pleistocene olivine basalt flows such as those exposed by the falls on Burney Creek (CDMG, 1994). The oldest "roof" rocks in the Peninsular Ranges date to the Paleozoic, such as limestone deposits near Riverside quarried for the concrete industry. The water erosion hazard on these soils is low, while the wind erosion hazard is moderate, due to the high percentage of silt (refer to TableVI-1). Therefore, the transfer would not expose people or structures to potential substantial adverse effects, including the risk of loss, injury, or death. The Modoc Plateau is a volcanic table land approximately 4,000 to 6,000 feet above mean sea level. [19]. These are Jurassic and Cretaceous age greywacke, chert, basalt, ultrabasic rocks and serpentinite from modified oceanic crust. 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. By contrast, the Trinity ophiolite is found in the east, known for its numerous ultramafic rocks and being one of the most extensive ophiolites in the US. Franciscan rocks have a complex geological structure. False. Project work may include post fire recovery efforts. Share sensitive information only on official, secure websites. Therefore, the Shasta County Building division would not be required to issue a development permit. flow of the Modoc Plateau exposed in a road cut about 4 miles northeast of Alturas on Highway 395. The east side of the Warner Mountains in particular has exposed rock in the many canyons, including finds of petrified wood and assorted gemstones. As discussed in Section1.0, Project Description, no development is proposed that would eventually be utilized for human occupancy. Surface fault rupture is not necessarily restricted to the area within an Alquist-Priolo Zone. They have a high shrink-swell potential and have a low water erosion hazard and low wind erosion hazard when bare (see TableVI-1). Areas along the northeastern shores of Big Lake are mapped as Recent Modoc basalt flows (CDMG, 1968). 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. At mid elevations, there are areas of Douglas-fir and grand fir (Abies grandis) forests to the north, and white fir and Douglas-fir forests to the south. These rocks date to the Cretaceous, with a lower sequence of conglomerate overlain by sandstone and shale, with huge ammonite fossils. The Modoc Plateau has a diverse geography, with portions draining into closed basins such as Goose Lake and Surprise Valley, and most of the remainder draining into the Pitt River, a tributary of the Sacramento River. These soils have formed in dissected lacustrine terraces from alluvium derived from diatomite lacustrine deposits (NRCS, 2000). Activities planned for the McArthur Swamp after the ownership transfer would not differ substantially from historic activities undertaken in the area since site reclamation earlier in the century. They are shallow, well drained cobbly loams of moderate permeability and are neutral to mildly acidic. ;] Includes some Mesozoic rocks. In addition to gold, platinum is sometimes found with gold placers. [3], Forested areas of the plateau include Ponderosa Pine (Pinus ponderosa), as well as other tree species such as California Buckeye (Aesculus californica). 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. In spite of low rainfall, the numerous lava tubes and volcanic fractures in the plateau produce the Fall River Springs, one of the largest springs in the US. Borehole Conditions The vault is a horizontal tunnel, located beneath 5 meters of overburden to maintain thermal stability. [13]. The plateau is thought to have been formed approximately 25 million years ago. The movement of the San Andreas Fault and Garlock Fault helped to induce arid conditions during the Cenozoic. Miners extracted placer gold or dug up fossil placers in the Weaverville Formation and Hornbrook Formation. These soils have a Capability Class rating of III to IV and are considered Prime Farmland when irrigated (NRCS, 2000). This region of the mountains was likely underthrusted by the adjoining plates, producing multiple schists around 380 to 400 million years ago in the Ordovician. Thick sequences of marine rocks from the Late Cretaceous through the Paleocene and Eocene are common in the mountains and on San Miguel Island. Abstract. 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. Consequently, these soils will continue to remain submerged on an annual basis. Hill (1915) published a sketch map of the geology of.the High-grade mining district, a small gold district in the north Warner Mountains. The Coast Range is at even higher risk for damaging landslides than other parts of coastal California due to sheared serpentinite in Franciscan basement rocks. Geothermal systems with evidence of magmatic heat, associated wi In fact, the East Cascades support an unusually high aquatic biodiversity among ecoregions in the U.S., including a large number of endemic freshwater snails and fish. Most intrusive igneous rocks are tonalite, granodiorite, quartz diorite or gabbro. The Modoc Plateau lies in the northeast corner of California as well as parts of Oregon and Nevada. In Washington, much of the ecoregion is within the ceded lands and usual and accustomed fishing areas of tribes. The Rocky Ledge fault trends northwesterly about three miles to the south of the transfer property (CDMG, 1994).