An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be seen or examined closely. However, in places where the overlying cover is removed through erosion or tectonic uplift, the rock may be exposed, or crop out; such exposure will happen most in areas where erosion is rapid and exceeds the weathering rate such as on steep hillsides, mountain ridges and tops, river banks, tectonically active areas. In Finland, glacial erosion during the last glacial maximum, followed by scouring by sea waves, followed by isostatic uplift has produced a large number of smooth coastal and littoral outcrops. Bedrock and superficial deposits may be exposed at the Earth's surface due to human excavations such as quarrying and building of transport routes. Outcrops allow direct observation and sampling of the bedrock in situ for geologic analysis and creating geologic maps.
In situ measurements are critical for proper analysis of geological history and outcrops are therefore important for understanding the geologic time scale of earth history. Some of the types of information that cannot be obtained except from bedrock outcrops or by precise drilling and coring operations, are structural geology features orientations, depositional features orientations, paleomagnetic orientations. Outcrops are very important for understanding fossil assemblages, paleo-environment, evolution as they provide a record of relative changes within geologic strata. Accurate description and sampling for laboratory analysis of outcrops made possible all of the geologic sciences and the development of fundamental geologic laws such as the law of superposition, the principle of original horizontality, principle of lateral continuity, the principle of faunal succession. On Ordnance Survey maps in Great Britain, cliffs are distinguished from outcrops: cliffs have a continuous line along the top edge with lines protruding down.
An outcrop example in California is the Vasquez Rocks, familiar from location shooting use in many films, composed of uplifted sandstone. Yana is another example of outcrops, located in Uttara Kannada district in India. Digital outcrop model List of rock formations Geological formation Geologic time scale Media related to Outcrops at Wikimedia Commons
Hayward Fault Zone
The Hayward Fault Zone is a geologic fault zone capable of generating destructive earthquakes. This fault is about 74 mi long, situated along the western base of the hills on the east side of San Francisco Bay, it runs through densely populated areas, including Richmond, El Cerrito, Oakland, San Leandro, Castro Valley, Union City and San Jose. The Hayward Fault is parallel to the San Andreas Fault, which lies offshore and through the San Francisco Peninsula. To the east of the Hayward lies the Calaveras Fault. In 2007 the Hayward Fault was discovered to merge with the Calaveras Fault east of San Jose at a depth of 4 miles, with the potential of creating earthquakes much larger than expected; some geologists have suggested that the Southern Calaveras should be renamed as the Southern Hayward. North of San Pablo Bay is the Rodgers Creek Fault, shown in 2016 to be linked with the Hayward Fault under San Pablo Bay to form a combined Hayward-Rodgers Creek Fault, 118 miles long, stretching from north of Healdsburg through Santa Rosa down to Alum Rock in San Jose.
Another fault further north, the Maacama Fault, is considered to be part of the "Hayward Fault subsystem". While the San Andreas Fault is the principal transform boundary between the Pacific Plate and the North American Plate, the Hayward-Rodgers Creek Fault takes up its share of the overall displacement of the two plates; the Pacific Plate is a major section of the Earth's crust expanding by the eruption of magma along the East Pacific Rise to the southeast. It is being subducted far to the northwest into the Aleutian Trench. In California, the plate is sliding northwestward along a transform boundary, the San Andreas Fault, toward the subduction zone. At the same time, the North American Plate is moving southwestward relative to the Earth's core, but southeastward relative to the Pacific Plate, due to the latter's much faster northwestward motion; the westward component of the North American Plate's motion results in some compressive force along the San Andreas and its associated faults, thus helping lift the Pacific Coast Ranges and other parallel inland ranges to the west of the Central Valley, in this region most notably the Diablo Range.
The Hayward Fault shares the same relative motions of the San Andreas. As with portions of other faults, a large extent of the Hayward Fault trace is formed from a narrow complex zone of deformation which can span hundreds of feet in width; the transform boundary defined by the San Andreas Fault is not straight, the stresses between the Pacific and North American Plates are diffused over a wide region of the West, extending as far as the eastern side of the Sierra Nevada Mountains. The Hayward Fault is one of the secondary faults in this diffuse zone, along with the Calaveras Fault to the east and the San Gregorio Fault, west of the San Andreas; the complete fault zone, including the Rodgers Creek fault, is divided by seismologists into three segments – Rodgers Creek, Northern Hayward, Southern Hayward. It is expected that these segments may fail singly or in adjacent pairs, creating earthquakes of varying magnitude; the Association of Bay Area Governments in concert with other government agencies has sponsored the analysis of local conditions and the preparation of maps indicative of the destructive potential of these earthquakes.
The various ABAG maps shown below represent some of the more possible combinations. While there are indications that a substantial earthquake on a nearby parallel fault can release stress and so decrease the near-term probability of an earthquake, the opposite appears to be true concerning sequential segments. A release on a major segment can increase the likelihood of an earthquake on an adjacent fault segment, increasing the likelihood of two major regional earthquakes within a period of a few months; the connection between the Rodgers Creek Fault Zone and the Hayward Fault Zone was unclear until 2015 when a survey of the floor of San Pablo Bay found that the ends of the two faults were smoothly linked between Point Pinole and Lower Tubbs Island. An alternate prior hypothesis suggested that the Hayward Fault and Rodgers Creek Fault were connected by a series of en echelon fault strands beneath San Pablo Bay; the new finding means that the Rodgers-Hayward system together could produce a quake with a magnitude as high as 7.2.
It is considered possible that a major seismic event on either fault may involve movement on the other, either concurrently or within an interval of up to several months. The Association of Bay Area Governments has prepared ground shaking maps that include a possible concurrent scenario. In October 2016, scientists found definitive evidence that the Rodgers Creek Fault and the Hayward Fault are linked together under San Pablo Bay. A simultaneous rupture of the connected Hayward-Rodgers Creek Fault – about 118 mi long from just north of Healdsburg down to Alum Rock in San Jose – could result in a major earthquake of magnitude 7.4 that "would cause extensive damage and loss of life with global economic impact". It has been suggested that the name "Rodgers Creek Fault" be retired and that the entire 118 mi fault be known as the "Hayward Fault"; the Calaveras Fault is continuous from the Sunol area south to Hollister. It was long believed that there was no connection between the Hayward Fault and the Calaveras, but geological studies suggest that the two may be connected.
If true, this link would have significant implications for the potential maximum strength of earthquakes on the Hayward, since this strength is determined by the maximum length of the fault ruptur
Loam is soil composed of sand, a smaller amount of clay. By weight, its mineral composition is about 40–40–20% concentration of sand-silt-clay, respectively; these proportions can vary to a degree and result in different types of loam soils: sandy loam, silty loam, clay loam, sandy clay loam, silty clay loam, loam. In the USDA textural classification triangle, the only soil, not predominantly sand, silt, or clay is called "loam". Loam soils contain more nutrients and humus than sandy soils, have better drainage and infiltration of water and air than silt and clay-rich soils, are easier to till than clay soils; the different types of loam soils each have different characteristics, with some draining liquids more efficiently than others. The soil's texture its ability to retain nutrients and water are crucial. Loam soil is suitable for growing most plant varieties. Bricks made of loam, mud and water, with an added binding material such as rice husks or straw, have been used in construction since ancient times.
Loam is considered ideal for gardening and agricultural uses because it retains nutrients well and retains water while still allowing excess water to drain away. A soil dominated by one or two of the three particle size groups can behave like loam if it has a strong granular structure, promoted by a high content of organic matter. However, a soil that meets the textural definition of loam can lose its characteristic desirable qualities when it is compacted, depleted of organic matter, or has clay dispersed throughout its fine-earth fraction. Loam is found in a majority of successful farms in regions around the world known for their fertile land. Loam soil is easy to work over a wide range of moisture conditions. Loam may be used for example in loam post and beam construction. Building crews can build a layer of loam on the inside of walls, which can help to control air humidity. Loam, combined with straw, can be used as a rough construction material to build walls; this is one of the oldest technologies for house construction in the world.
Within this there are two broad methods: unfired bricks. Loess – A predominantly silt-sized clastic sediment of accumulated wind-blown dust Grain size Soil texture
A summit is a point on a surface, higher in elevation than all points adjacent to it. The topographic terms acme, apex and zenith are synonymous; the term top is used only for a mountain peak, located at some distance from the nearest point of higher elevation. For example, a big massive rock next to the main summit of a mountain is not considered a summit. Summits near a higher peak, with some prominence or isolation, but not reaching a certain cutoff value for the quantities, are considered subsummits of the higher peak, are considered part of the same mountain. A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top. Summit may refer to the highest point along a line, trail, or route; the highest summit in the world is Everest with height of 8844.43 m above sea level. The first official ascent was made by Sir Edmund Hillary, they reached the mountain`s peak in 1953. Whether a highest point is classified as a summit, a sub peak or a separate mountain is subjective; the UIAA definition of a peak is.
Otherwise, it's a subpeak. In many parts of the western United States, the term summit refers to the highest point along a road, highway, or railroad. For example, the highest point along Interstate 80 in California is referred to as Donner Summit and the highest point on Interstate 5 is Siskiyou Mountain Summit. A summit climbing differs from the common mountaineering. Summit expedition requires: 1+ year of training, a good physical shape, a special gear. Although a huge part of climber’s stuff can be left and taken at the base camps or given to porters, there is a long list of personal equipment. In addition to common mountaineers’ gear, Summit climbers need to take Diamox and bottles of oxygen. There are special requirements for crampons, ice axe, rappel device, etc. Geoid Hill – Landform that extends above the surrounding terrain Nadir Summit accordance Peak finder Summit Climbing Gear List
In geology, bedrock is the lithified rock that lies under a loose softer material called regolith within the surface of the crust of the Earth or other terrestrial planets. Bedrock refers to the substructure composed of hard rock exposed or buried at the earths surface, an exposed portion of bedrock is called an outcrop. Bedrock may have various chemical and mineralogical compositions and can be igneous, metamorphic or sedimentary in origin; the bedrock may be overlain by weathered regolith which includes soil and the subsoil. The surface of the bedrock beneath the soil cover is known as rockhead in engineering geology, its identification by digging, drilling or geophysical methods is an important task in most civil engineering projects. Superficial deposits can be thick, such that the bedrock lies hundreds of meters below the surface. Bedrock when exposed or within the subsurface may experience weathering and erosion by external factors. Weathering may be physical or chemical and alters the structure of the rock and may cause it to erode and or alter over time based on the interactions between the mineralogy and its interactions.
Bedrock may experience subsurface weathering at its upper boundary, forming saprolite. A geologic map of an area will show the distribution of differing bedrock types, rock that would be exposed at the surface if all soil or other superficial deposits were removed. Geology – The study of the composition, physical properties, history of Earth's components, the processes by which they are shaped. Outcrop Regolith – A layer of loose, heterogeneous superficial deposits covering solid rock Soil – mixture of organic matter, gases and organisms that together support life Weathering – Breaking down of rocks and minerals as well as artificial materials through contact with the Earth's atmosphere and waters Rafferty, John P. "Bedrock GEOLOGY". Encyclopedia Britannica. Encyclopedia Britannica. Retrieved 1 April 2019. Harris, The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. Vol. 1. 5th ed. Farmington Hills, MI: Gale, 2014. P515-516. Media related to Bedrock at Wikimedia Commons
Sonoma Valley is a valley located in southeastern Sonoma County, California, in the San Francisco Bay Area. Known as the birthplace of the California wine industry, the valley is home to some of the earliest vineyards and wineries in the state, some of which survived the phylloxera epidemic of the 1870s and the impact of prohibition in the early 20th century. Today, the valley's wines are protected by the US Federal Government's Sonoma Valley and Carneros AVAs. Sonoma Valley offers a wide range of year-round festivals and events, including the Sonoma International Film Festival. Points of interest include the Quarryhill Botanic Garden, Mission San Francisco Solano, Jack London State Historic Park, Sonoma State Historic Park and the Blue Wing Inn of 1840; the valley is located in southeastern Sonoma County between the Mayacamas Mountains and Sonoma Mountains. It stretches from San Pablo Bay in the south to the city of Santa Rosa in the north. Sonoma Creek flows down the valley to the bay; the area includes the incorporated city of Sonoma and part of the City of Santa Rosa, as well as numerous unincorporated communities, including Kenwood and Glen Ellen near Santa Rosa and, near Sonoma, El Verano, Boyes Hot Springs, Fetters Hot Springs, Agua Caliente.
Once a valley of the coastal Miwok and Wintun peoples, called the "Valley of the Moon" in their legends, the valley was selected by the Franciscan order of Spain as the site to build the Mission San Francisco Solano, the northernmost mission in their chain of twenty-one missions built in Alta California. Established in 1823 and named to honor St. Francis Solanus, Mission Solano was the sole California mission established under the rule of a newly independent Mexico. Within two generations of the Spaniards' arrival, the indigenous societies of the region were dispossessed of their land and decimated by diseases to which Europeans were resistant. Soon after the Sonoma mission was built, it was secularized by the Mexican government, under the orders of Lieutenant General Mariano Guadalupe Vallejo, el Pueblo de Sonoma was laid out in the standard form of a Mexican town, centered around the historic plaza, still the town's focal point. Known as "Valley of the Seven Moons" The raising of the first California Bear Flag and Vallejo's arrest in 1846 by a band of Americans claiming to act on the orders of Col. John C.
Fremont was the initial act. Vallejo transferred his allegiance with US statehood, with his amassed land holdings guided the development of the town and dispensed large ranches throughout the valley. California's first wineries were established here, including Buena Vista Winery and Gundlach Bundschu; the other communities in the valley, such as Kenwood, Glen Ellen and Boyes Hot Springs, were founded in the 19th century, some as resorts centered on the geothermic hot springs that still well up from deep within the earth. Boyes Hot Springs and Agua Caliente were popular health retreats for tourists from San Francisco and points beyond until the middle of the 20th century. Today the Sonoma Mission Inn in Boyes Hot Springs remains as a main destination resort, the wineries, the historic sites, the area's natural beauty are the main tourist attractions. In October 2017, the area was badly affected by wildfire; the phrase "Valley of the Moon" was first recorded in an 1850 report by General Mariano Guadalupe Vallejo to the California Legislature.
According to Jack London, who had a ranch there, the Native American word Sonoma means "valley of the moon." He used it for his book of the same name. But there are several other possible translations for Sonoma. According to the Miwok tribes that lived in the valley, the Pomo, it meant "valley of the moon" or "many moons." White settlers may have accidentally translated the words "many moons" into "valley of moons." Miwok legends say that the moon rose from this valley, or was "nestled" in the valley, or may have sprung up multiple times in one night. In the native languages there is a recurring ending tso-noma, from tso, the earth. Other sources say Sonoma comes from the Patwin tribes west of the Sacramento River, their Wintu word for "nose." Per California Place Names, "the name is doubtless derived from a Patwin word for'nose', which Padre Arroyo gives as sonom." Spaniards may have found an Indian chief with a prominent protuberance and applied the nickname of Chief Nose to the village and the territory.
The name may have applied to a nose-shaped geographic feature. The Sonoma Valley is part of the Coast Range Physiographic provence. Basement rocks that make up the valley at great depth are the Great Valley Sequence shale and conglomerate deposited in a continental slope- to abysmal plain environment via turbidite flows; the Cretaceous Great Valley Sequence overlies and contacts the Franciscan Complex along the Coast Range Thrust. The Jurassic-Cretaceous Franciscan Complex includes crumpled, uplifted terranes that have resulted from the subduction of the former oceanic Farallon Plate under the North American continent. During late Miocene-Pliocene time the area was attended by volcanism which are interbedded with the late Miocene-Pliocene Petaluma Formation; the Petaluma Formation was a fresh-water river system flowing from east to west and through the volcanics. At that time, volcanic lava flows and river sands and gravels were deposited together, hence "interbedded lavas and gravels"; the v