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45-596: The type locality for the Coldwater Sandstone is in Coldwater Canyon, a western branch of the Sespe River a few miles north of Fillmore . The unit is typically around half a mile thick, ranging from 2,500 to 3,200 feet through most of its extent, although it thins westward to around 1,000 feet thick in the hills north of El Capitan State Beach . From there going west to Gaviota , the unit gradually grades into

90-617: A marked change to red beds of river systems of Oligocene age in the western and central segments. Limestones and dolomites of the marine Miocene Monterey Formation are found in the Santa Ynez Mountains and in the Coast Ranges to the north. The distinctive feature of the Transverse Ranges besides their anomalous orientation is that they are bounded by east-west trending faults. Most are left slip, strike slip faults . In

135-591: A range of 117 to 127 million barrels of oil recoverable using current technology for the entire Santa Barbara-Ventura Basin Province. Some onshore oil fields produce from the Coldwater, including the Ojai Oil Field north of Santa Paula and Sespe oil field north of Fillmore, not far from the type locality for the formation. The unit is of middle to upper Eocene age, being deposited in a shallow marine environment, during

180-560: A result, there is high topographic relief throughout the range, and other than in marginal areas (e.g. the San Fernando Valley ) and a few river valleys (such as Lockwood Valley and Big Bear Valley), there are no large, flat basins within the ranges. The mountains are notable for being steep and difficult to traverse. There are few passes that are sufficiently low or wide enough to accommodate significant volumes of traffic. This has resulted in situations where major cities are linked to

225-399: A time in which the sea was receding and becoming more shallow. Because the process was not uniform, with periods of shallow-water deposition alternating with deeper water conditions, the predominantly sandstone unit is interbedded with siltstones and shales, with the siltstone and shale making up around 20% of the total composition. Late in the period of deposition, large oyster beds appear in

270-528: A topography particularly characteristic of the ridge north of Goleta , where the Coldwater accounts for almost all of the terrain above approximately 1,000 feet. While the unit is exposed prominently throughout the Santa Ynez Mountains, it dips steeply to the south and vanishes underneath the coastal plain and then the Santa Barbara Channel . Well bores in the numerous oil and gas fields in the Channel show

315-485: Is known as the "Montecito Overturn". Fossils of numerous mollusks , including many species of the genus Turritella can be found in the Coldwater, particularly near the top of the formation where the water at time of deposition was shallowest. Outcrops along Old San Marcos Pass Road above Goleta and near the contact with the Sespe Formation are rich locations for finding remnants of these sea-snails. Elsewhere near

360-706: Is the type locality. The concept is similar to type site in archaeology . Transverse Ranges The Transverse Ranges are a group of mountain ranges of southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa Barbara, Ventura, Los Angeles, San Bernardino, Riverside and Kern counties. The Peninsular Ranges lie to

405-604: The 2018 Southern California mudflows , may be cut off from timely road access to the rest of Southern California. Major peaks of the Transverse Ranges with at least 500 feet (150 m) of prominence, listed by height: This segment begins at Point Conception in Santa Barbara County, and include the Santa Ynez Mountains that run parallel to the coast behind Santa Barbara and the San Rafael Mountains on

450-596: The Mesozoic , mostly granites, can be found on Mount Pinos and generally in regions east of Tejon Pass . The youngest rocks are Cenozoic sedimentary and volcanic rocks that can be found throughout the ranges. The western segment is distinctive for the large thickness of Cretaceous and Cenozoic sedimentary rocks, estimated to be up to 10 kilometers. The thickest deposits of these are in the Santa Barbara Channel and Ventura basin. These are mostly marine in origin with

495-768: The Pacific Ocean and the northern Channel Islands . Onshore the Los Angeles Basin lies at the southern boundary of the western and central segments of the ranges. Major passes not along the San Andreas Fault include Gaviota Pass , San Marcos Pass , the Conejo Grade , Newhall Pass , and Cahuenga Pass . The Transverse Ranges manifest themselves as a series of roughly parallel ridges with an average height of 3,000–8,000 feet (910–2,440 m). The ranges are dissected by young, steep streams of relatively low flow rate; as

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540-778: The Pinto , Eagle , and Orocopia Mountains are within the eastern segment. The Mojave Desert and California's low desert, including the Coachella Valley , are at the eastern end of the ranges. Ranges north of the western segment that are nearly transverse but are part of the California Coast Ranges include the San Rafael Mountains and the Sierra Madre Mountains . Likewise, the Tehachapi Mountains north of

585-585: The Sacate Formation , a similar but shalier and more siltstone-rich unit which is also conformably overlain on the Cozy Dell Formation . The Coldwater and Sacate Formations are sometimes considered as a single unit, particularly underneath the Santa Barbara Channel where they appear in drill cores. The Gaviota Formation is deposited conformably on top of the Coldwater-Sacate in the western part of

630-873: The San Gabriel Mountains and San Gabriel fault . The central segment includes mountains that range eastward to the San Andreas fault . The eastern segment extends from the Cajon Pass at the San Andreas fault eastward to the Colorado Desert. The central and eastern segments (near the San Andreas fault) have the highest elevations. Most of the ranges lie in the California chaparral and woodlands ecoregion. Lower elevations are dominated by chaparral and scrubland, while higher elevations support large conifer forests. Most of

675-615: The WWF -designated California montane chaparral and woodlands ecoregion , but the eastern points of the range touch two desert regions, the Mojave Desert and the Colorado Desert section of the Sonoran Desert . The Carrizo Plain adjoins the northern edge of the Transverse Range. Chaparral is a common feature of the Transverse Ranges. Common plant associates in chaparral , especially in

720-525: The most important oil-producing areas in the United States. The plant place of the Transverse ranges include coastal sage scrub , oak woodland and savanna , and pinyon-juniper woodland at lower elevations, and yellow pine forest , Lodgepole Pine , and subalpine forest at higher elevations. The Angeles and Los Padres National Forests cover portions of the Transverse ranges. The ranges are part of

765-522: The Coldwater and the other formations up from their deposition environments to their present prominent locations in the Santa Ynez Range. In the area north and northeast of Santa Barbara , on the south slope of the Santa Ynez Mountains eastward to near Ojai , the compression and folding associated with tectonic movements have been sufficiently intense to overturn the rock units so that the older ones are on top. This stretch of overturned rock formations

810-749: The Gaviota Formation overlying the Cozy Dell directly, with no intervening Coldwater, excepting the offshore portion of the Capitan Oil Field, in which the Coldwater Formation is present as a natural-gas-bearing unit, underlying the Gaviota. As a potential hydrocarbon resource, the unit is considered to be equivalent to the Sacate, and is grouped with the lower-lying Cozy Dell Shale and Matilija Sandstone as

855-640: The Gaviota-Sacate-Matilija Sandstone Play. The likely source rocks for any petroleum accumulation in the Coldwater-Sacate are the lower-lying organic-rich shale units, such as the Cozy Dell and the Juncal-Anita Formations . Since this deep-lying play is incompletely explored, the estimates for hydrocarbon resources are speculative, with the United States Bureau of Ocean Energy Management, Regulation and Enforcement giving

900-560: The Mojave Desert, although nearly transverse, are the southern end of the Sierra Nevada . Mountain ranges with peaks exceeding 4,500 feet (1,400 m), listed west to east, include: Examples of smaller mountain and hill ranges include: The climate in most of the range is Csb ( Warm-summer Mediterranean ) under the Köppen climate classification ; the upper reaches of San Gorgonio Mountain have an alpine tundra climate ( ET ), while

945-536: The San Andreas Fault, which separates those segments from the Mojave Desert. The eastern segment bounds the southern Mojave Desert. Notable passes along the San Andreas fault include Tejon Pass , Cajon Pass , and San Gorgonio Pass . Components of Transverse Ranges to the north and east of the fault include the San Bernardino Mountains , Little San Bernardino Mountains , Pinto and Eagle Mountains . The western and southern boundaries are acknowledged to be

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990-665: The Santa Barbara Channel and Ventura Basin. Much oil has pooled in the Monterey Formation, which is produced onshore and offshore. In the eastern Santa Barbara Channel oil is held in younger sedimentary rocks. The Los Angeles Basin south of the western segment, formed during rotation of that segment away from the Peninsular Ranges. It is also a site of prolific oil production. The California Geologic Survey states: Great thicknesses of Cenozoic petroleum-rich sedimentary rocks have been folded and faulted, making California one of

1035-563: The Transverse Ranges and the Peninsular Ranges to the south. There are a number of important freeways that cross the Transverse Ranges, such as (from west to east) US-101, I-5 at Tejon Pass , SR 14 at Soledad Pass , and I-15 at Cajon Pass . These highways link Southern California with places to the north and northeast like San Francisco and Las Vegas , respectively. With the exception of several high passes on less-traveled SR 33 , SR 2 , SR 330 . SR 18 and SR 38 , none of these passes are at high elevations, with Cajon Pass being at

1080-922: The Transverse Ranges; San Miguel , Santa Rosa , Santa Cruz and Anacapa Islands are a westward extension of the Santa Monica Mountains. The Ranges include the steep San Gabriel Mountains northeast of Los Angeles , the Sierra Pelona Mountains just south of the San Andreas fault, the Tehachapi Mountains southeast of Bakersfield, the Verdugo Mountains , the Liebre-Sawmill Mountains, the San Rafael Hills , Puente Hills , San Jose Hills , and Chino Hills . The San Bernardino Mountains , Little San Bernardino Mountains , and

1125-485: The age of the unit using magnetostratigraphy , and gave its period of deposition as from 39.5 Ma (million years ago) to 42.5 Ma. Additionally, studies of the correlation of the underlying Cozy Dell and Matilija Sandstone with similar units in the California Central Valley, along with paleomagnetic data, show that the tectonic block on which the Coldwater and its surrounding formations were deposited – including

1170-591: The bounding faults are left slip Santa Ynez and Pine Mountain Faults. The San Gabriel Fault and San Andreas bound the central segment. The eastern segment is bounded by the Pinto Mountain Fault in the north and the Salton Creek Fault in the south. The large thickness of marine sediments in the western segment have made it a habitat for oil. Several dozen fields are found onshore and offshore, particularly in

1215-587: The central and eastern segments, including the San Gabriel and San Bernardino Mountains. The oldest basement (deepest) rocks are of Proterozoic age, and are found in the San Gabriel Mountains and the San Bernardino Mountains. The Jurassic - Cretaceous Franciscan Assemblage is found in the western section of the ranges and is the presumed basement in this segment. Exposed plutonic rocks from

1260-524: The dual unit's extent, and the Sespe Formation appears conformably on top of it elsewhere. The Coldwater outcrops predominantly on the south slope of the Santa Ynez Range, and on the crest of the range at San Marcos Pass . Cathedral Peak, the 3,333-foot prominence directly north of Santa Barbara, is within the Coldwater unit. Because the sandstone beds are resistant to erosion, wherever they dip steeply, they form distinctive hogback ridges and dip-slopes,

1305-507: The fault moved east to open the Gulf of California . The crust within the Pacific Plate south of the ranges can not easily make the left turn westward as the entire plate moves northwestward, forcing pieces of the crust to compress and lift. Prior to this shift of the fault to create the left bend, northwest–southeast trending rock belts in all of the Transverse Ranges began to rotate clockwise in

1350-418: The faults outside that province. Between the western segment and the Peninsular Ranges to the south is the complex Malibu Coast—Santa Monica— Hollywood fault , which exists as the border between these two mostly geologically unitary provinces. These faults are part of the same thrust fault system south of the northern Channel Islands of San Miguel, Santa Rosa, and Anacapa Islands. North of the western segment

1395-570: The interaction of the Pacific Plate and the North American Plate along the dextral (right slip) San Andreas Fault system. Their orientation along an east–west axis as opposed to the general northwest–southeast trend of most California ranges results from a pronounced left step in the San Andreas Fault that occurred in the Pliocene ( c.  4 million years ago) when southern reaches of

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1440-451: The lower northern slopes of the range have a desert ( BW ) or steppe ( BS ) climate; most of the nearby lowlands to the south and west have a Hot-summer Mediterranean climate ( Csa ). Snow falls above 6,000 feet (1,800 m) most winters, and above 3,000 feet (910 m) every few years. It is rare for elevations above 8,000 feet (2,400 m) to go multiple winters without snow, even during severe droughts. Due to relatively low humidity,

1485-670: The mountain ranges, including the Oxnard Plain of coastal Ventura County , the Santa Clarita Valley north of Los Angeles, the San Fernando Valley , which is mostly included in the City of Los Angeles. The Los Angeles Basin, which includes the portion of Los Angeles County south of the Santa Monica Mountains and most of Orange County , and the Inland Empire basin, which includes the cities of San Bernardino and Riverside , lie between

1530-888: The other side of the Santa Ynez Valley . The western Transverse Ranges also include the Topatopa Mountains and the Santa Susana Mountains of Ventura County and Los Angeles County, the Simi Hills , the Santa Monica Mountains that run along the Pacific coast behind Malibu , and whose eastern portion are known as the Hollywood Hills , and the Chalk Hills . The northern Channel Islands of California are also part of

1575-492: The outboard Pacific plate. Because the Monterey plate was then beneath southern California, the capture resulted in pulling of the overlying crust out and northward from the rest of California. Rocks of the Transverse Ranges exhibit extreme differences in geologic age and composition, varying from sedimentary rocks in the western Santa Ynez and volcanic rocks in the Santa Monica Mountains to primarily granitic and metamorphic rock in

1620-474: The ranges in the system are fault blocks , and were uplifted by tectonic movements late in the Cenozoic Era . West of Tejon Pass , the primary rock types are varied, with a mix of sedimentary, volcanic, and metamorphic rocks, while regions east of the pass are dominated by plutonic granitic and metasedimentary rocks. The western and central segments of the Transverse Ranges are bounded to the north and east by

1665-420: The regional snow line lies at about 14,000–16,000 feet (4,300–4,900 m), above the highest elevation of the range; as such, snow does not persist year-round except in the form of snow patches . The tree line lies at about 11,000 feet (3,400 m); San Gorgonio Mountain is the only peak with an alpine environment. The Transverse Ranges result from a complex of tectonic forces and faulting stemming from

1710-518: The rest of the state by relatively few roads; for example, the vast majority of traffic between the Central Valley and the Los Angeles area is routed through Tejon Pass. This results in significant traffic issues throughout Southern California when a pass has to be shut down due to heavy snow or construction. Occasionally, major cities, such as Santa Barbara during the 2005 La Conchita landslide and

1755-528: The right shear of Pacific Plate – North American Plate motion. This tectonic rotation began in Early Miocene Time and continues today. The total rotation is about 90° in the Western Transverse Ranges and less (about 40°) in the eastern ranges. Catalina Island shows the most rotation: almost 120°. A mechanism proposed for the rotation event is capture of the subducting Monterey plate by

1800-528: The south. The name is due to the ranges' east–west orientation, making them transverse to the general northwest–southeast orientation of most of California's coastal mountains. The ranges extend from west of Point Conception eastward approximately 500 kilometers into the Mojave and Colorado Desert . The geology and topography of the ranges express three distinct segments that have contrasting elevations, rock types, and vegetation. The western segment extends to

1845-518: The stratigraphic record, indicating a brackish-water nearshore environment. The source rock for the sediment making up the Coldwater was mostly granitic , and pebbles or cobbles of granite and quartzite appear in some of the nearshore sandstones near the top of the unit. At its top the unit grades into the redbeds and conglomerates of the Sespe Formation, which was deposited in a floodplain, riverine, and estuarine environment onshore. A 1996 study by Donald R. Prothero and Robert J. Emry determined

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1890-400: The top contact with the Sespe, the remnants of oyster beds can be found. Type locality (geology) Type locality , also called type area , is the locality where a particular rock type , stratigraphic unit or mineral species is first identified. If the stratigraphic unit in a locality is layered, it is called a stratotype , whereas the standard of reference for unlayered rocks

1935-506: The transition between coastal chaparral and coastal sage scrub, include California sagebrush and Toyon , the latter shrub having its southern distribution limit defined by the Transverse Ranges. Pinyon-juniper woodland is common on the north slopes of the San Gabriel and San Bernardino Mountains. This ecosystem is easily visible in the well-travelled Soledad Pass region, between Pearblossom and Santa Clarita . A number of densely populated coastal plains and interior valleys lie between

1980-450: The western and central segments many of the faults are thrust faults . Faults in the Coast Ranges and Peninsular Ranges trend northwest-southeast and butt into the east-west trending faults of the Transverse Ranges. Because all of these faults are considered active and seismic but they do to cut each other, the only geometry that satisfies that observation is if the east-west faults and Transverse Ranges are rotating clockwise with respect to

2025-421: The western part of the Transverse Ranges – has rotated clockwise almost 90 degrees since the time of deposition, also moving north-northwest from its original location. This finding is consistent with earlier studies that found evidence for the large clockwise rotation of the Transverse Ranges in California. Uplift along the Santa Ynez Fault during the Quaternary period – the last 2.5 million years – has brought

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