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29-554: Geologically, the Tinajas Altas Mountains are a southeastward extension of the block faulted Gila Mountains , and what are now the Tinajas Altas Mountains were actually considered part of the Gila Mountains until about the middle of the 20th century. The two ranges are separated by Cipriano Pass , also referred to as "Smugglers Pass," about two miles northwest of Raven Butte , 2,694 feet (821 m) which

58-468: A graben , or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley , which may be filled by water forming a rift lake . The axis of the rift area may contain volcanic rocks , and active volcanism is a part of many, but not all, active rift systems. Major rifts occur along the central axis of most mid-ocean ridges , where new oceanic crust and lithosphere

87-449: A lacustrine environment or in a restricted marine environment, although not all rifts contain such sequences. Reservoir rocks may be developed in pre-rift, syn-rift and post-rift sequences. Effective regional seals may be present within the post-rift sequence if mudstones or evaporites are deposited. Just over half of estimated oil reserves are found associated with rifts containing marine syn-rift and post-rift sequences, just under

116-880: A graben between two horsts – the Vosges mountains (in France ) and the Black Forest (in Germany ), and also the Rila – Rhodope Massif in Bulgaria , Southeast Europe , including the well defined horsts of Belasitsa (linear horst), Rila mountain (vaulted domed shaped horst) and Pirin mountain – a horst forming a massive anticline situated between the complex graben valleys of Struma and that of Mesta . Tilted type block mountains have one gently sloping side and one steep side with an exposed scarp, and are common in

145-403: A kind of orogeneses in extensional settings, which is referred as to rifting orogeny. Once rifting ceases, the mantle beneath the rift cools and this is accompanied by a broad area of post-rift subsidence. The amount of subsidence is directly related to the amount of thinning during the rifting phase calculated as the beta factor (initial crustal thickness divided by final crustal thickness), but

174-438: A mid-oceanic ridge and a set of conjugate margins separated by an oceanic basin. Rifting may be active, and controlled by mantle convection . It may also be passive, and driven by far-field tectonic forces that stretch the lithosphere. Margin architecture develops due to spatial and temporal relationships between extensional deformation phases. Margin segmentation eventually leads to the formation of rift domains with variations of

203-557: A series of separate segments that together form the linear zone characteristic of rifts. The individual rift segments have a dominantly half-graben geometry, controlled by a single basin-bounding fault. Segment lengths vary between rifts, depending on the elastic thickness of the lithosphere. Areas of thick colder lithosphere, such as the Baikal Rift have segment lengths in excess of 80 km, while in areas of warmer thin lithosphere, segment lengths may be less than 30 km. Along

232-717: A simple relay ramp at the overlap between two major faults of the same polarity, to zones of high structural complexity, particularly where the segments have opposite polarity. Accommodation zones may be located where older crustal structures intersect the rift axis. In the Gulf of Suez rift, the Zaafarana accommodation zone is located where a shear zone in the Arabian-Nubian Shield meets the rift. Rift flanks or shoulders are elevated areas around rifts. Rift shoulders are typically about 70 km wide. Contrary to what

261-888: Is Fortuna Foothills in the east of the Yuma Valley adjacent to the Gila Mountains. The Tinajas Altas Mountains exhibit a variety of flora and fauna species. Among the notable flora present is the elephant tree, ( Bursera microphylla ), which species exhibits a contorted multi-furcate architecture. Fault block Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by tectonic and localized stresses in Earth's crust . Large areas of bedrock are broken up into blocks by faults . Blocks are characterized by relatively uniform lithology . The largest of these fault blocks are called crustal blocks . Large crustal blocks broken off from tectonic plates are called terranes . Those terranes which are

290-535: Is a notable dark-colored volcanic feature on the eastern flank of the otherwise light-colored granitic range. The range is named for the Tinajas Altas ("High Tanks"), which are a series of perched waterholes on the range's eastern side approximately four miles north of the international boundary. The waterholes figured prominently in the history of the area as they were for many years the only reliable source of water for many miles. Native Americans, principally

319-402: Is also affected by the degree to which the rift basin is filled at each stage, due to the greater density of sediments in contrast to water. The simple 'McKenzie model' of rifting, which considers the rifting stage to be instantaneous, provides a good first order estimate of the amount of crustal thinning from observations of the amount of post-rift subsidence. This has generally been replaced by

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348-451: Is created along a divergent boundary between two tectonic plates . Failed rifts are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot . Two of these evolve to the point of seafloor spreading, while the third ultimately fails, becoming an aulacogen . Most rifts consist of

377-622: The Basin and Range region of the western United States. An example of a graben is the basin of the Narmada River in India , between the Vindhya and Satpura horsts. Rift In geology , a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics . Typical rift features are a central linear downfaulted depression, called

406-591: The East African Rift zone. Death Valley in California is a smaller example. There are two main types of block mountains; uplifted blocks between two faults and tilted blocks mainly controlled by one fault. Lifted type block mountains have two steep sides exposing both sides scarps, leading to the horst and graben terrain seen in various parts of Europe including the Upper Rhine valley,

435-473: The Moho topography, including proximal domain with fault-rotated crustal blocks, necking zone with thinning of crustal basement , distal domain with deep sag basins, ocean-continent transition and oceanic domain. Deformation and magmatism interact during rift evolution. Magma-rich and magma-poor rifted margins may be formed. Magma-rich margins include major volcanic features. Globally, volcanic margins represent

464-659: The 'flexural cantilever model', which takes into account the geometry of the rift faults and the flexural isostasy of the upper part of the crust. Some rifts show a complex and prolonged history of rifting, with several distinct phases. The North Sea rift shows evidence of several separate rift phases from the Permian through to the Earliest Cretaceous , a period of over 100 million years. Rifting may lead to continental breakup and formation of oceanic basins. Successful rifting leads to seafloor spreading along

493-682: The Hia C-eḍ O'odham, also utilized the waterholes as an important camp prior to European settlement. The range lies in the Lower Colorado subdivision of the Sonoran Desert . This subdivision is sometimes referred to as the Colorado Desert and encompasses much of southeastern California, southwestern Arizona, northwestern Sonora, and northeastern Baja California. The subdivision is characterized by minimal precipitation, and

522-475: The Sierra Tinajas Altas which would suggest that they are a longer extension of the Tinajas Altas Mountains into Mexico. The two ranges, however, share no surface connection so they are not the same. The Sierra de la Lechuguilla/Sierra Tinajas Altas range are instead on a parallel alignment to the southeast of the Tinajas Altas Mountains proper. The closest community to the Tinajas Altas Mountains

551-572: The area around the Tinajas Altas Mountains averages only about three inches of rainfall per year. Mexican topographic maps and United States Geological Survey (USGS) maps of the region disagree on the name of an adjacent range lying to the southeast of the Tinajas Altas Mountains. In the United States this small range is referred to as the Sierra de la Lechuguilla , but in Mexico they are called

580-452: The axis of the rift the position, and in some cases the polarity (the dip direction), of the main rift bounding fault changes from segment to segment. Segment boundaries often have a more complex structure and generally cross the rift axis at a high angle. These segment boundary zones accommodate the differences in fault displacement between the segments and are therefore known as accommodation zones. Accommodation zones take various forms, from

609-469: The development of isolated basins. In subaerial rifts, for example, drainage at the onset of rifting is generally internal, with no element of through drainage. As the rift evolves, some of the individual fault segments grow, eventually becoming linked together to form the larger bounding faults. Subsequent extension becomes concentrated on these faults. The longer faults and wider fault spacing leads to more continuous areas of fault-related subsidence along

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638-431: The faults have a large vertical displacement. Adjacent raised blocks ( horsts ) and down-dropped blocks ( grabens ) can form high escarpments . Often the movement of these blocks is accompanied by tilting, due to compaction or stretching of the crust at that point. Fault-block mountains often result from rifting , an indicator of extensional tectonics . These can be small or form extensive rift valley systems, such as

667-594: The full thickness of the lithosphere are called microplates. Continent-sized blocks are called variously microcontinents, continental ribbons, H-blocks, extensional allochthons and outer highs. Because most stresses relate to the tectonic activity of moving plates , most motion between blocks is horizontal, that is parallel to the Earth's crust by strike-slip faults . However vertical movement of blocks produces much more dramatic results. Landforms ( mountains , hills, ridges, lakes, valleys, etc.) are sometimes formed when

696-567: The majority of passive continental margins. Magma-starved rifted margins are affected by large-scale faulting and crustal hyperextension. As a consequence, upper mantle peridotites and gabbros are commonly exposed and serpentinized along extensional detachments at the seafloor. Many rifts are the sites of at least minor magmatic activity , particularly in the early stages of rifting. Alkali basalts and bimodal volcanism are common products of rift-related magmatism. Recent studies indicate that post-collisional granites in collisional orogens are

725-404: The product of rifting magmatism at converged plate margins. The sedimentary rocks associated with continental rifts host important deposits of both minerals and hydrocarbons . SedEx mineral deposits are found mainly in continental rift settings. They form within post-rift sequences when hydrothermal fluids associated with magmatic activity are expelled at the seabed. Continental rifts are

754-432: The rift axis. Significant uplift of the rift shoulders develops at this stage, strongly influencing drainage and sedimentation in the rift basins. During the climax of lithospheric rifting, as the crust is thinned, the Earth's surface subsides and the Moho becomes correspondingly raised. At the same time, the mantle lithosphere becomes thinned, causing a rise of the top of the asthenosphere. This brings high heat flow from

783-521: The sites of significant oil and gas accumulations, such as the Viking Graben and the Gulf of Suez Rift . Thirty percent of giant oil and gas fields are found within such a setting. In 1999 it was estimated that there were 200 billion barrels of recoverable oil reserves hosted in rifts. Source rocks are often developed within the sediments filling the active rift ( syn-rift ), forming either in

812-491: The upwelling asthenosphere into the thinning lithosphere, heating the orogenic lithosphere for dehydration melting, typically causing extreme metamorphism at high thermal gradients of greater than 30 °C. The metamorphic products are high to ultrahigh temperature granulites and their associated migmatite and granites in collisional orogens, with possible emplacement of metamorphic core complexes in continental rift zones but oceanic core complexes in spreading ridges. This leads to

841-549: Was previously thought, elevated passive continental margins (EPCM) such as the Brazilian Highlands , the Scandinavian Mountains and India's Western Ghats , are not rift shoulders. The formation of rift basins and strain localization reflects rift maturity. At the onset of rifting, the upper part of the lithosphere starts to extend on a series of initially unconnected normal faults , leading to

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