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104-487: (Redirected from Río Salinas ) Salinas River may refer to: Salinas River (California) , US Salinas River National Wildlife Refuge Salinas River State Beach Salinas River (Guam) Salinas River (Guatemala) Salinas River (Mexico) Salinas River (Minas Gerais) , Brazil [REDACTED] Topics referred to by the same term This disambiguation page lists articles about distinct geographical locations with

208-439: A consequence, a powerful source generating plate motion is the excess density of the oceanic lithosphere sinking in subduction zones. When the new crust forms at mid-ocean ridges, this oceanic lithosphere is initially less dense than the underlying asthenosphere, but it becomes denser with age as it conductively cools and thickens. The greater density of old lithosphere relative to the underlying asthenosphere allows it to sink into

312-450: A few tens of millions of years. Armed with the knowledge of a new heat source, scientists realized that Earth would be much older, and that its core was still sufficiently hot to be liquid. By 1915, after having published a first article in 1912, Alfred Wegener was making serious arguments for the idea of continental drift in the first edition of The Origin of Continents and Oceans . In that book (re-issued in four successive editions up to

416-465: A large submarine outflow canyon . The current hypothesis is that, at one point in the Miocene epoch , many millions of years ago, the river was probably located in the vicinity of what is now Los Angeles County , having been carried north to its present position due to tectonic plate drift at the same rate as currently. When the ancient Salinas river was in that southern location, it may have served as

520-579: A layer of basalt (sial) underlies the continental rocks. However, based on abnormalities in plumb line deflection by the Andes in Peru, Pierre Bouguer had deduced that less-dense mountains must have a downward projection into the denser layer underneath. The concept that mountains had "roots" was confirmed by George B. Airy a hundred years later, during study of Himalayan gravitation, and seismic studies detected corresponding density variations. Therefore, by

624-400: A misnomer as there is no force "pushing" horizontally, indeed tensional features are dominant along ridges. It is more accurate to refer to this mechanism as "gravitational sliding", since the topography across the whole plate can vary considerably and spreading ridges are only the most prominent feature. Other mechanisms generating this gravitational secondary force include flexural bulging of

728-754: A part of the chain of 21 missions , then commissioned by the Spanish government in Alta California , now the U.S. State of California . All three of the Salinas Valley missions remain intact to this day, the Soledad mission having evolved into the City of Soledad , and the San ;Miguel mission having evolved into the unincorporated village of San Miguel . The San Antonio mission

832-558: A secondary phenomenon of this basically vertically oriented mechanism. It finds its roots in the Undation Model of van Bemmelen . This can act on various scales, from the small scale of one island arc up to the larger scale of an entire ocean basin. Alfred Wegener , being a meteorologist , had proposed tidal forces and centrifugal forces as the main driving mechanisms behind continental drift ; however, these forces were considered far too small to cause continental motion as

936-407: A solid crust and mantle and a liquid core, but there seemed to be no way that portions of the crust could move around. Many distinguished scientists of the time, such as Harold Jeffreys and Charles Schuchert , were outspoken critics of continental drift. Despite much opposition, the view of continental drift gained support and a lively debate started between "drifters" or "mobilists" (proponents of

1040-478: A static Earth without moving continents up until the major breakthroughs of the early sixties. Two- and three-dimensional imaging of Earth's interior ( seismic tomography ) shows a varying lateral density distribution throughout the mantle. Such density variations can be material (from rock chemistry), mineral (from variations in mineral structures), or thermal (through thermal expansion and contraction from heat energy). The manifestation of this varying lateral density

1144-438: Is mantle convection from buoyancy forces. How mantle convection directly and indirectly relates to plate motion is a matter of ongoing study and discussion in geodynamics. Somehow, this energy must be transferred to the lithosphere for tectonic plates to move. There are essentially two main types of mechanisms that are thought to exist related to the dynamics of the mantle that influence plate motion which are primary (through

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1248-494: Is 13.26 inches (337 mm) per year, and the average annual rainfall since 2000 is 11.01 inches (280 mm) per year. Recent increases in water use, primarily in the agricultural sector, and the damming of the river and its tributaries may be contributing factors causing the now mostly-dry condition of the riverbed. The Monterey County Water Resources Agency currently operates a water use monitoring program which requires that all agricultural water users self-report annually on

1352-527: Is based on their modes of formation. Oceanic crust is formed at sea-floor spreading centers. Continental crust is formed through arc volcanism and accretion of terranes through plate tectonic processes. Oceanic crust is denser than continental crust because it has less silicon and more of the heavier elements than continental crust . As a result of this density difference, oceanic crust generally lies below sea level , while continental crust buoyantly projects above sea level. Average oceanic lithosphere

1456-461: Is called a plate boundary . Plate boundaries are where geological events occur, such as earthquakes and the creation of topographic features such as mountains , volcanoes , mid-ocean ridges , and oceanic trenches . The vast majority of the world's active volcanoes occur along plate boundaries, with the Pacific plate's Ring of Fire being the most active and widely known. Some volcanoes occur in

1560-533: Is called the geosynclinal theory . Generally, this was placed in the context of a contracting planet Earth due to heat loss in the course of a relatively short geological time. It was observed as early as 1596 that the opposite coasts of the Atlantic Ocean—or, more precisely, the edges of the continental shelves —have similar shapes and seem to have once fitted together. Since that time many theories were proposed to explain this apparent complementarity, but

1664-592: Is especially known as one of the principal regions for lettuce and artichokes in the United States. The river is shallow above ground, periodically dry, with much of its flow underground. The underground flow results from numerous aquifers, which are recharged by water from the Salinas, especially from the Nacimiento and San Antonio lakes during the dry months. In the 18th and early 19th centuries,

1768-492: Is in motion, presents a problem. The same holds for the African, Eurasian , and Antarctic plates. Gravitational sliding away from mantle doming: According to older theories, one of the driving mechanisms of the plates is the existence of large scale asthenosphere/mantle domes which cause the gravitational sliding of lithosphere plates away from them (see the paragraph on Mantle Mechanisms). This gravitational sliding represents

1872-408: Is invoked as the major driving force, through slab pull along subduction zones. Gravitational sliding away from a spreading ridge is one of the proposed driving forces, it proposes plate motion is driven by the higher elevation of plates at ocean ridges. As oceanic lithosphere is formed at spreading ridges from hot mantle material, it gradually cools and thickens with age (and thus adds distance from

1976-548: Is now embedded in Fort Hunter Liggett (a U.S. Army garrison). The mission period ended with the Mexican revolution and the replacement of missions with ranchos in the 1820s and 30s. Ranchos around the Salinas river included Rancho Las Salinas , Rancho Bolsa Nueva y Moro Cojo The Rancho period ended with the 1848 American seizure of California from Mexico. The City of Monterey , about 10 miles south of

2080-415: Is still advocated to explain the break-up of supercontinents during specific geological epochs. It has followers amongst the scientists involved in the theory of Earth expansion . Another theory is that the mantle flows neither in cells nor large plumes but rather as a series of channels just below Earth's crust, which then provide basal friction to the lithosphere. This theory, called "surge tectonics",

2184-409: Is still capable of quickly transforming itself back into a fast-flowing river. In rainfall-induced flood conditions, it can at times measure over a mile in width. During the 20th century, such flood conditions are reported to have generally occurred approximately once every 3–10 years. The last similar flooding event along the river was reported in 1998. The atypical drought-breaking rains of

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2288-464: Is the basis for the proposal of what is presently thought to be the most probable geological history of the Salinas River. The long and deep submarine Monterey Canyon dwarfs all other such canyons along the Pacific coast of North America. However, the known flow-rates and drainage area of the Salinas River in no way indicate the river as it presently stands was ever capable of creating such

2392-488: Is to consider the relative rate at which each plate is moving as well as the evidence related to the significance of each process to the overall driving force on the plate. One of the most significant correlations discovered to date is that lithospheric plates attached to downgoing (subducting) plates move much faster than other types of plates. The Pacific plate, for instance, is essentially surrounded by zones of subduction (the so-called Ring of Fire) and moves much faster than

2496-407: Is typically 100 km (62 mi) thick. Its thickness is a function of its age. As time passes, it cools by conducting heat from below, and releasing it raditively into space. The adjacent mantle below is cooled by this process and added to its base. Because it is formed at mid-ocean ridges and spreads outwards, its thickness is therefore a function of its distance from the mid-ocean ridge where it

2600-435: Is used. It asserts that super plumes rise from the deeper mantle and are the drivers or substitutes of the major convection cells. These ideas find their roots in the early 1930s in the works of Beloussov and van Bemmelen , which were initially opposed to plate tectonics and placed the mechanism in a fixed frame of vertical movements. Van Bemmelen later modified the concept in his "Undation Models" and used "Mantle Blisters" as

2704-567: The Appalachian Mountains of North America are very similar in structure and lithology . However, his ideas were not taken seriously by many geologists, who pointed out that there was no apparent mechanism for continental drift. Specifically, they did not see how continental rock could plow through the much denser rock that makes up oceanic crust. Wegener could not explain the force that drove continental drift, and his vindication did not come until after his death in 1930. As it

2808-689: The Carquinez Strait , to empty through the present San Francisco Bay . People first appeared along the California coast approximately 13,000 years ago, during the latter part of the Pleistocene epoch . Up until European settlement in Alta California , the indigenous people who lived along the Salinas River were the Rumsen in the northern Salinas Valley , and the Salinan in

2912-631: The Gabilan Mountain Range . It flows past Atascadero and Paso Robles (to Monterey). It receives the natural outflow of the Estrella River and the controlled outflows of the Nacimiento and San Antonio reservoirs through their respective river tributaries in southern Monterey County . The river passes through the active San Ardo Oil Field , and then into and through the Salinas Valley. It flows past many small towns in

3016-652: The Las Tablas Creek tributary of the Nacimiento River, and Jack Creek, a tributary of Paso Robles Creek west of Templeton . In regards to the area's historical beaver population, after a period of depletion by 19th-century fur trappers, California golden beaver ( Castor canadensis subauratus ) populations rebounded and expanded their range from the Salinas River mouth to the San Antonio River tributary below its reservoir and beyond to

3120-422: The chemical subdivision of these same layers into the mantle (comprising both the asthenosphere and the mantle portion of the lithosphere) and the crust: a given piece of mantle may be part of the lithosphere or the asthenosphere at different times depending on its temperature and pressure. The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates , which ride on

3224-594: The de Anza Expedition in March ;1776: ... there are obtained also many good salmon which enter the river to spawn. Since they are fond of fresh water they ascend the streams so far that I am assured that even at the mission of San Antonio some of the fish which ascend the Rio de Monterey have been caught. Of this fish we ate almost every day while we were here. If Father Font was describing salmon (and not steelhead), then his records suggest that salmon once traversed

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3328-736: The fluid-like solid the asthenosphere . Plate motions range from 10 to 40 millimetres per year (0.4 to 1.6 in/year) at the Mid-Atlantic Ridge (about as fast as fingernails grow), to about 160 millimetres per year (6.3 in/year) for the Nazca plate (about as fast as hair grows). Tectonic lithosphere plates consist of lithospheric mantle overlain by one or two types of crustal material: oceanic crust (in older texts called sima from silicon and magnesium ) and continental crust ( sial from silicon and aluminium ). The distinction between oceanic crust and continental crust

3432-473: The lithosphere and asthenosphere . The division is based on differences in mechanical properties and in the method for the transfer of heat . The lithosphere is cooler and more rigid, while the asthenosphere is hotter and flows more easily. In terms of heat transfer, the lithosphere loses heat by conduction , whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. This division should not be confused with

3536-573: The scientific theory that Earth 's lithosphere comprises a number of large tectonic plates , which have been slowly moving since 3–4 billion years ago. The model builds on the concept of continental drift , an idea developed during the first decades of the 20th century. Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s. The processes that result in plates and shape Earth's crust are called tectonics . Tectonic plates also occur in other planets and moons. Earth's lithosphere,

3640-530: The 367-acre (1.49 km ) Salinas River National Wildlife Refuge and its outflow to Monterey Bay is blocked by sand dunes except during winter high-water flows. The land owners altered the course of the river by filling in the river bed during the dry season. This allowed them to farm all of their land and use the water as they saw fit. The old stream bed went from the Old Salinas River, joining Elkhorn Slough on Monterey Bay near Moss Landing , to

3744-489: The Aleutian Islands before returning to the spawning grounds in the tributaries of the Salinas River. As noted, the trout life-cycle which requires an annual migration to the sea and then back, was broken during the dry-river conditions of the years 2013–2016, and the current fate of the river's steelhead trout remains uncertain at best. Father Pedro Font described salmon in the Salinas River ( Rio de Monterey ) on

3848-598: The Earth's rotation and the Moon as main driving forces for the plates. The vector of a plate's motion is a function of all the forces acting on the plate; however, therein lies the problem regarding the degree to which each process contributes to the overall motion of each tectonic plate. The diversity of geodynamic settings and the properties of each plate result from the impact of the various processes actively driving each individual plate. One method of dealing with this problem

3952-414: The Salinas River main stem and up its San Antonio River tributary to Mission San Antonio near what is now Jolon . This may support other historical observer records primarily in the form of oral histories taken and compiled by H.A. Franklin that placed Chinook salmon in the mainstem as far south as Atascadero where Highway 41 crosses, as well as southern tributaries of the Salinas River, including

4056-565: The Salinas River that supported steelhead trout once included Paso Robles Creek, Jack Creek, Atascadero Creek, Santa Margarita Creek and Trout Creek in the upper reaches of the River. It once took over ten days for the steelhead from the upper part of the watershed to migrate to the Pacific Ocean near the City of Marina on Monterey Bay. From there, the steelhead would migrate to the area west of

4160-416: The Salinas River watershed. At one time it was also an important middle link for salmon migrating from the Salinas River to Tassajara Creek and other tributaries. Estrella River also remains undammed. A 2015 assessment of the survivability of the river's steelhead trout indicated that such a survival may be unlikely, due to the river's recent tendency to run dry for most of the year. Other tributaries of

4264-541: The actual motions of the Pacific plate and other plates associated with the East Pacific Rise do not correlate mainly with either slab pull or slab push, but rather with a mantle convection upwelling whose horizontal spreading along the bases of the various plates drives them along via viscosity-related traction forces. The driving forces of plate motion continue to be active subjects of on-going research within geophysics and tectonophysics . The development of

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4368-483: The arrival of Hispanic and American settlers in the area, the Salinas River was once home to abundant fish and beaver populations. Regarding historical fish populations, the Arroyo Seco is the only major Salinas River tributary which has remained undammed and as of 2015, still supported a small remnant population of the threatened Central Coast Steelhead trout ( Oncorhynchus mykiss ) that once spawned throughout in

4472-478: The assumption of a solid Earth made these various proposals difficult to accept. The discovery of radioactivity and its associated heating properties in 1895 prompted a re-examination of the apparent age of Earth . This had previously been estimated by its cooling rate under the assumption that Earth's surface radiated like a black body . Those calculations had implied that, even if it started at red heat , Earth would have dropped to its present temperature in

4576-399: The asthenosphere. This theory was launched by Arthur Holmes and some forerunners in the 1930s and was immediately recognized as the solution for the acceptance of the theory as originally discussed in the papers of Alfred Wegener in the early years of the 20th century. However, despite its acceptance, it was long debated in the scientific community because the leading theory still envisaged

4680-577: The banks of the Salinas river (then referred to as el Rio de Monterey .) The new missions built along the banks of the Salinas river were the Mission Nuestra Señora de la Soledad established in 1791, and the Mission San Miguel Arcángel , established in 1797. The Mission San Antonio de Padua was established during this same time period in the Salinas Valley, but not on the river itself. These three missions were

4784-476: The base of the lithosphere. Slab pull is therefore most widely thought to be the greatest force acting on the plates. In this understanding, plate motion is mostly driven by the weight of cold, dense plates sinking into the mantle at trenches. Recent models indicate that trench suction plays an important role as well. However, the fact that the North American plate is nowhere being subducted, although it

4888-495: The bathymetry of the deep ocean floors and the nature of the oceanic crust such as magnetic properties and, more generally, with the development of marine geology which gave evidence for the association of seafloor spreading along the mid-oceanic ridges and magnetic field reversals , published between 1959 and 1963 by Heezen, Dietz, Hess, Mason, Vine & Matthews, and Morley. Simultaneous advances in early seismic imaging techniques in and around Wadati–Benioff zones along

4992-472: The bay north of Moss Landing . Possibly because of flooding and human activity sometime between 1908 and 1910, the river mouth changed by 5.5 miles (8.8 km) to a new channel by Mulligan Hill. The old river bed was converted to farmland. The historic increase in agriculture and settlement in the area, and the related increased water consumption demands have had a significant impact on the Salinas River. The river now typically remains dry or without flow for

5096-577: The capital of Alta California . The earliest recorded use of this name for the river was a reference made by Fr.  Pedro Font on 4 March 1776. This name continued in use as late as 1850. After the American annexation of the area, it was renamed the Salinas River . The river was apparently renamed as the "Salinas" river by an American cartographer in 1858, ten years after the 1848 American seizure of Alta California from Mexico . In 1858

5200-413: The concept was of continents plowing through oceanic crust. Therefore, Wegener later changed his position and asserted that convection currents are the main driving force of plate tectonics in the last edition of his book in 1929. However, in the plate tectonics context (accepted since the seafloor spreading proposals of Heezen, Hess, Dietz, Morley, Vine, and Matthews (see below) during the early 1960s),

5304-415: The deep mantle at subduction zones, providing most of the driving force for plate movement. The weakness of the asthenosphere allows the tectonic plates to move easily towards a subduction zone. For much of the first quarter of the 20th century, the leading theory of the driving force behind tectonic plate motions envisaged large scale convection currents in the upper mantle, which can be transmitted through

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5408-534: The discussions treated in this section) or proposed as minor modulations within the overall plate tectonics model. In 1973, George W. Moore of the USGS and R. C. Bostrom presented evidence for a general westward drift of Earth's lithosphere with respect to the mantle, based on the steepness of the subduction zones (shallow dipping towards the east, steeply dipping towards the west). They concluded that tidal forces (the tidal lag or "friction") caused by Earth's rotation and

5512-466: The driving force for horizontal movements, invoking gravitational forces away from the regional crustal doming. The theories find resonance in the modern theories which envisage hot spots or mantle plumes which remain fixed and are overridden by oceanic and continental lithosphere plates over time and leave their traces in the geological record (though these phenomena are not invoked as real driving mechanisms, but rather as modulators). The mechanism

5616-453: The estimated amount of groundwater pumped from the shrinking Salinas Valley aquifer. This is in contrast to some areas of the country where various water authorities both monitor and regulate water use for agriculture. The previous ecosystem of the Salinas River, which once included steelhead trout, and numerous other species throughout the full length of a once year-round flowing river, has clearly been drastically impacted in recent years by

5720-425: The expanding heavy demands of agricultural water use in the Salinas Valley, and the resulting most typical dry-river conditions. Despite regularly running dry, the Salinas River has at the same time had occasional notable floods. Among these were the flood of 1964 and the flood of 1995. The geological history of the ancient Salinas River is currently held by tectonic plate theory to likely be rather unique among

5824-473: The final one in 1936), he noted how the east coast of South America and the west coast of Africa looked as if they were once attached. Wegener was not the first to note this ( Abraham Ortelius , Antonio Snider-Pellegrini , Eduard Suess , Roberto Mantovani and Frank Bursley Taylor preceded him just to mention a few), but he was the first to marshal significant fossil and paleo-topographical and climatological evidence to support this simple observation (and

5928-695: The forces acting upon it by the Moon are a driving force for plate tectonics. As Earth spins eastward beneath the Moon, the Moon's gravity ever so slightly pulls Earth's surface layer back westward, just as proposed by Alfred Wegener (see above). Since 1990 this theory is mainly advocated by Doglioni and co-workers ( Doglioni 1990 ), such as in a more recent 2006 study, where scientists reviewed and advocated these ideas. It has been suggested in Lovett (2006) that this observation may also explain why Venus and Mars have no plate tectonics, as Venus has no moon and Mars' moons are too small to have significant tidal effects on

6032-588: The geographical latitudinal and longitudinal grid of Earth itself. These systematic relations studies in the second half of the nineteenth century and the first half of the twentieth century underline exactly the opposite: that the plates had not moved in time, that the deformation grid was fixed with respect to Earth's equator and axis, and that gravitational driving forces were generally acting vertically and caused only local horizontal movements (the so-called pre-plate tectonic, "fixist theories"). Later studies (discussed below on this page), therefore, invoked many of

6136-718: The interiors of plates, and these have been variously attributed to internal plate deformation and to mantle plumes. Tectonic plates may include continental crust or oceanic crust, or both. For example, the African plate includes the continent and parts of the floor of the Atlantic and Indian Oceans. Some pieces of oceanic crust, known as ophiolites , failed to be subducted under continental crust at destructive plate boundaries; instead these oceanic crustal fragments were pushed upward and were preserved within continental crust. Three types of plate boundaries exist, characterized by

6240-412: The large scale convection cells) or secondary. The secondary mechanisms view plate motion driven by friction between the convection currents in the asthenosphere and the more rigid overlying lithosphere. This is due to the inflow of mantle material related to the downward pull on plates in subduction zones at ocean trenches. Slab pull may occur in a geodynamic setting where basal tractions continue to act on

6344-421: The lithosphere before it dives underneath an adjacent plate, producing a clear topographical feature that can offset, or at least affect, the influence of topographical ocean ridges. Mantle plumes and hot spots are also postulated to impinge on the underside of tectonic plates. Slab pull : Scientific opinion is that the asthenosphere is insufficiently competent or rigid to directly cause motion by friction along

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6448-403: The lower mantle, there is a slight westward component in the motions of all the plates. They demonstrated though that the westward drift, seen only for the past 30 Ma, is attributed to the increased dominance of the steadily growing and accelerating Pacific plate. The debate is still open, and a recent paper by Hofmeister et al. (2022) revived the idea advocating again the interaction between

6552-589: The majority of the year, and downstream (north) of King City remained fully dry or with zero flow during the years 2013–2016. During the Spanish / Mexican / Mission period, the river was named El Rio de Monterey . When first encountered by the Spanish Portola Expedition on 27 September 1769, the members of the expedition at first suspected that they had found the Carmel River , that had been discovered earlier by Vizcaíno . One of

6656-405: The many geographical, geological, and biological continuities between continents. In 1912, the meteorologist Alfred Wegener described what he called continental drift, an idea that culminated fifty years later in the modern theory of plate tectonics. Wegener expanded his theory in his 1915 book The Origin of Continents and Oceans . Starting from the idea (also expressed by his forerunners) that

6760-600: The many rivers of the western North American seaboard: The shifting position of the raised section of the Pacific Plate that the river flows through was in ancient times aligned with the North American Plate at a point far south of its present location. The discovery of the Monterey Canyon , the remarkably deep submarine canyon extending into the Pacific from the mouth of the Salinas River,

6864-429: The matching of the rock formations along these edges. Confirmation of their previous contiguous nature also came from the fossil plants Glossopteris and Gangamopteris , and the therapsid or mammal-like reptile Lystrosaurus , all widely distributed over South America, Africa, Antarctica, India, and Australia. The evidence for such an erstwhile joining of these continents was patent to field geologists working in

6968-568: The motion picture of the Atlantic region", processes that anticipated seafloor spreading and subduction . One of the first pieces of geophysical evidence that was used to support the movement of lithospheric plates came from paleomagnetism . This is based on the fact that rocks of different ages show a variable magnetic field direction, evidenced by studies since the mid–nineteenth century. The magnetic north and south poles reverse through time, and, especially important in paleotectonic studies,

7072-438: The motion. At a subduction zone the relatively cold, dense oceanic crust sinks down into the mantle, forming the downward convecting limb of a mantle cell , which is the strongest driver of plate motion. The relative importance and interaction of other proposed factors such as active convection, upwelling inside the mantle, and tidal drag of the Moon is still the subject of debate. The outer layers of Earth are divided into

7176-590: The mouth of a river that drained the catchment of the Colorado River , that currently flows from the Rocky Mountains into the Sea of Cortez in western Mexico . The Salinas River is also thought to have been, about 700,000 years ago, the outlet for prehistoric Lake Corcoran . Lake Corcoran once filled much of what is now California's Central Valley , prior to the lake's developing an outlet via

7280-424: The mouth of the Salinas (at that time), was the capital city of Alta California , and the site of the 7 July 1846 invasion by American warships, commanded by Admiral J.D. Sloat . When Americans first arrived, the river approached Monterey Bay near Mulligan Hill just north of Marina . It turned north to flow parallel to the bay, separated by sand dunes, before flowing into Elkhorn Slough and finally entering

7384-462: The newer name "Salinas" first appeared on an American-made map as the Rio Salinas , most probably so renamed after the nearby American-founded town of Salinas , which in turn appears to have first been named in 1854 after the old Rancho Las Salinas land grant, parts of which included the city. The river begins in southern San Luis Obispo County , approximately 2.5 miles (4.0 km) east of

7488-470: The north pole, and each continent, in fact, shows its own "polar wander path". During the late 1950s, it was successfully shown on two occasions that these data could show the validity of continental drift: by Keith Runcorn in a paper in 1956, and by Warren Carey in a symposium held in March 1956. The second piece of evidence in support of continental drift came during the late 1950s and early 60s from data on

7592-407: The oceanic crust is suggested to be in motion with the continents which caused the proposals related to Earth rotation to be reconsidered. In more recent literature, these driving forces are: Forces that are small and generally negligible are: For these mechanisms to be overall valid, systematic relationships should exist all over the globe between the orientation and kinematics of deformation and

7696-437: The oceanic lithosphere and the thicker continental lithosphere, each topped by its own kind of crust. Along convergent plate boundaries , the process of subduction carries the edge of one plate down under the other plate and into the mantle . This process reduces the total surface area (crust) of the Earth. The lost surface is balanced by the formation of new oceanic crust along divergent margins by seafloor spreading, keeping

7800-443: The party members, Father Crespi, then proposed that the [Salinas] river might be a different river, and that it should therefore be given a new name, however he appears to have been over-ruled by the other members of his party at the time. The first agreed upon name for the river, as it subsequently appeared on many Spanish and Mexican maps, was Rio de Monterey , presumably being named after the newly founded nearby town of Monterey ,

7904-407: The planet. In a paper by it was suggested that, on the other hand, it can easily be observed that many plates are moving north and eastward, and that the dominantly westward motion of the Pacific Ocean basins derives simply from the eastward bias of the Pacific spreading center (which is not a predicted manifestation of such lunar forces). In the same paper the authors admit, however, that relative to

8008-399: The plate as it dives into the mantle (although perhaps to a greater extent acting on both the under and upper side of the slab). Furthermore, slabs that are broken off and sink into the mantle can cause viscous mantle forces driving plates through slab suction. In the theory of plume tectonics followed by numerous researchers during the 1990s, a modified concept of mantle convection currents

8112-426: The plates of the Atlantic basin, which are attached (perhaps one could say 'welded') to adjacent continents instead of subducting plates. It is thus thought that forces associated with the downgoing plate (slab pull and slab suction) are the driving forces which determine the motion of plates, except for those plates which are not being subducted. This view however has been contradicted by a recent study which found that

8216-408: The present continents once formed a single land mass (later called Pangaea ), Wegener suggested that these separated and drifted apart, likening them to "icebergs" of low density sial floating on a sea of denser sima . Supporting evidence for the idea came from the dove-tailing outlines of South America's east coast and Africa's west coast Antonio Snider-Pellegrini had drawn on his maps, and from

8320-629: The present course where the main channel's mouth is directly on the Pacific Ocean . The old Salinas River channel that diverts north behind the sand dunes along the ocean, acts as an overflow channel during the rainy season. Commencing from Hill Town running south along the western banks of the Salinas River to Gonzales is River Road. This road also falls along the edge of the Santa Lucia Highlands AVA , giving rise to its designation as River Road Wine Trail . Before

8424-459: The relationships recognized during this pre-plate tectonics period to support their theories (see reviews of these various mechanisms related to Earth rotation the work of van Dijk and collaborators). Of the many forces discussed above, tidal force is still highly debated and defended as a possible principal driving force of plate tectonics. The other forces are only used in global geodynamic models not using plate tectonics concepts (therefore beyond

8528-428: The relative position of the magnetic north pole varies through time. Initially, during the first half of the twentieth century, the latter phenomenon was explained by introducing what was called "polar wander" (see apparent polar wander ) (i.e., it was assumed that the north pole location had been shifting through time). An alternative explanation, though, was that the continents had moved (shifted and rotated) relative to

8632-399: The ridge). Cool oceanic lithosphere is significantly denser than the hot mantle material from which it is derived and so with increasing thickness it gradually subsides into the mantle to compensate the greater load. The result is a slight lateral incline with increased distance from the ridge axis. This force is regarded as a secondary force and is often referred to as " ridge push ". This is

8736-614: The rigid outer shell of the planet including the crust and upper mantle , is fractured into seven or eight major plates (depending on how they are defined) and many minor plates or "platelets". Where the plates meet, their relative motion determines the type of plate boundary (or fault ): convergent , divergent , or transform . The relative movement of the plates typically ranges from zero to 10 cm annually. Faults tend to be geologically active, experiencing earthquakes , volcanic activity , mountain-building , and oceanic trench formation. Tectonic plates are composed of

8840-399: The river valley provided the route of El Camino Real , the principal overland route from southern to northern Alta California , used by Spanish explorers and missionaries and early Mexican settlers. Tectonic plate theory Plate tectonics (from Latin tectonicus , from Ancient Greek τεκτονικός ( tektonikós )  'pertaining to building') is

8944-471: The river was first discovered by non-Native peoples via the Portola expedition , it was reported by them as being a "river watering a luxuriant plain" filled with fish weighing 8 to 10 pounds (3.6 to 4.5 kg). As of the end of 2016, the river had been transformed into little more than a dry bedded run-off feature for the majority of its length. Until 1989 the Salinas River had a continuous flow throughout

9048-484: The same name. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Salinas_River&oldid=1072525549 " Category : Place name disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Salinas River (California) In 1769, when

9152-652: The southern Salinas Valley . The Chalon and Esselen peoples also lived in the general vicinity of the Salinas River. The Salinas river was first sighted by European settlers on 27 September 1769. This first European contact with the river was recorded by the Spanish "colonizing expedition" of Gaspar de Portolà . As was the practice of the Spanish government in the New World at the time, soldiers and priests were then typically sent out together on such colonizing expeditions. The Portolá expedition included Franciscan priests, who soon thereafter established two missions along

9256-491: The southern hemisphere. The South African Alex du Toit put together a mass of such information in his 1937 publication Our Wandering Continents , and went further than Wegener in recognising the strong links between the Gondwana fragments. Wegener's work was initially not widely accepted, in part due to a lack of detailed evidence but mostly because of the lack of a reasonable physically supported mechanism. Earth might have

9360-708: The summit point of Pine Ridge, at a point just off of Agua Escondido Road, coming down off of the slopes of the Los ;Machos Hills of the Los Padres National Forest . The only dam situated directly on the Salinas River (the Salinas Dam ) forms the small Santa Margarita Reservoir. The Salinas flows down the valley bounded on its southwestern side by the Santa Lucia Mountain Range , and bounded on its northeastern side by

9464-481: The theory of plate tectonics was the scientific and cultural change which occurred during a period of 50 years of scientific debate. The event of the acceptance itself was a paradigm shift and can therefore be classified as a scientific revolution, now described as the Plate Tectonics Revolution . Around the start of the twentieth century, various theorists unsuccessfully attempted to explain

9568-502: The theory) and "fixists" (opponents). During the 1920s, 1930s and 1940s, the former reached important milestones proposing that convection currents might have driven the plate movements, and that spreading may have occurred below the sea within the oceanic crust. Concepts close to the elements of plate tectonics were proposed by geophysicists and geologists (both fixists and mobilists) like Vening-Meinesz, Holmes, and Umbgrove. In 1941, Otto Ampferer described, in his publication "Thoughts on

9672-476: The total surface area constant in a tectonic "conveyor belt". Tectonic plates are relatively rigid and float across the ductile asthenosphere beneath. Lateral density variations in the mantle result in convection currents, the slow creeping motion of Earth's solid mantle. At a seafloor spreading ridge , plates move away from the ridge, which is a topographic high, and the newly formed crust cools as it moves away, increasing its density and contributing to

9776-429: The trenches bounding many continental margins, together with many other geophysical (e.g., gravimetric) and geological observations, showed how the oceanic crust could disappear into the mantle, providing the mechanism to balance the extension of the ocean basins with shortening along its margins. All this evidence, both from the ocean floor and from the continental margins, made it clear around 1965 that continental drift

9880-507: The upper Salinas River watershed. More recent accounts suggested that beaver are no longer found along the northern reaches of the river, a recent comprehensive survey found beaver throughout the entire Salinas River mainstem and virtually all of its major tributaries, including the Estrella River. The use of the river for irrigation in the Salinas Valley makes it one of the most productive agricultural regions in California. It

9984-408: The valley, including King City , Greenfield , and Soledad , where it combines with the flash-flood prone Arroyo Seco , its fourth major tributary (in wet years). It flows 3 miles (4.8 km) south of the city of Salinas before cutting through Fort Ord and flows into central Monterey Bay approximately 3 miles west of Castroville . The final stretch of the river forms a lagoon protected by

10088-467: The way the plates move relative to each other. They are associated with different types of surface phenomena. The different types of plate boundaries are: Tectonic plates are able to move because of the relative density of oceanic lithosphere and the relative weakness of the asthenosphere . Dissipation of heat from the mantle is the original source of the energy required to drive plate tectonics through convection or large scale upwelling and doming. As

10192-506: The winter of 2016–2017 restored the river's flow to its lower northern reaches in January ;2017. The current most typical dry or zero flow state of the majority of the river may be more the result of human activity than of any recent changes in weather patterns. Rainfall patterns of recent years in the Salinas area have not significantly changed from historical average rainfall patterns; the 139-year average annual rainfall in Salinas

10296-600: The year, stretching back to at least 1941 when the United States Geological Survey (USGS) began complete monitoring records in the Salinas area. Most probably primarily due to recent increases in agricultural water demand in the Salinas Valley, and the resultant lowering of water tables, the lower reaches of the Salinas river (north of King City) remained entirely dry during the three years 2013–2016. Nonetheless, with sufficiently heavy rains, and on rare occasions, this now normally dry runoff feature

10400-531: Was feasible. The theory of plate tectonics was defined in a series of papers between 1965 and 1967. The theory revolutionized the Earth sciences, explaining a diverse range of geological phenomena and their implications in other studies such as paleogeography and paleobiology . In the late 19th and early 20th centuries, geologists assumed that Earth's major features were fixed, and that most geologic features such as basin development and mountain ranges could be explained by vertical crustal movement, described in what

10504-599: Was formed. For a typical distance that oceanic lithosphere must travel before being subducted, the thickness varies from about 6 km (4 mi) thick at mid-ocean ridges to greater than 100 km (62 mi) at subduction zones. For shorter or longer distances, the subduction zone, and therefore also the mean, thickness becomes smaller or larger, respectively. Continental lithosphere is typically about 200 km (120 mi) thick, though this varies considerably between basins, mountain ranges, and stable cratonic interiors of continents. The location where two plates meet

10608-424: Was observed early that although granite existed on continents, seafloor seemed to be composed of denser basalt , the prevailing concept during the first half of the twentieth century was that there were two types of crust, named "sial" (continental type crust) and "sima" (oceanic type crust). Furthermore, it was supposed that a static shell of strata was present under the continents. It therefore looked apparent that

10712-443: Was popularized during the 1980s and 1990s. Recent research, based on three-dimensional computer modelling, suggests that plate geometry is governed by a feedback between mantle convection patterns and the strength of the lithosphere. Forces related to gravity are invoked as secondary phenomena within the framework of a more general driving mechanism such as the various forms of mantle dynamics described above. In modern views, gravity

10816-575: Was supported in this by researchers such as Alex du Toit ). Furthermore, when the rock strata of the margins of separate continents are very similar it suggests that these rocks were formed in the same way, implying that they were joined initially. For instance, parts of Scotland and Ireland contain rocks very similar to those found in Newfoundland and New Brunswick . Furthermore, the Caledonian Mountains of Europe and parts of

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