WICHG30910a [USEMAP] [USEMAP] What is a Tectonostratigraphic Terrane? terrane_map_compld Terranes can be: • Native – showing shared traits with North American crust, indicating an origin adjacent to North America. • Exotic – Far-traveled, not born adjacent to North America • Superterranes – amalgamated with other terranes before accretion to the continental margin. [USEMAP] MESOZOIC [USEMAP] During the Mesozoic, subduction of the Farallon Plate formed a volcanic arc and the associated compression folded and thrust-faulted the Paleozoic sediments. Note the overall thickening of the continent, which will produce the gravitational potential energy which will help extend this region once compressional forces relax. The Western Collage •Cordillera an collage of microplates and arcs –accreted during the Paleozoic and Mesozoic –terrains have different rock types and fossil assemblages that cannot be correlated –suspect terrains--fault-bounded regions that cannot be correlated –exotic terrains--clearly from somewhere else – [USEMAP] Accreted or “suspect” terranes mapsuspected.jpg copy 00047DDCTS ABA78158: Dott & Prothero [USEMAP] KORDILERY KORDILERY 2561_1413 Antler Orogeny in Devonian-Carb. Basin and Range extension Active margin Passive margin [USEMAP] Paleozoic Passive Margin • Existed in Late Precambrian and Paleozoic • Craton and cratonic basin deposits • Miogeocline continental shelf deposits Antler Orogeny (300 (300-375 Ma) 375 Ma) • Late Devonian - Mississippian • Collision of the arc with a passive margin • Roberts Mountain Allochton thrust over the passive margin • A series of foreland basins formed in eastern Nevada [USEMAP] [USEMAP] Orogeneze: antlerská, kolize klamathského ostrovního oblouku v devonu a spodním karbonu [USEMAP] [USEMAP] [USEMAP] Mesozoic 2561_1413 Passive margin Active margin [USEMAP] Sonoma Orogeny (200-280 Ma) • Permo -Triassic • Collision of Arc With a Passive Margin • Island Arc Terrains Were Accreted • golconda allochthon Thrust Partly Over Roberts Mountain Allochthon [USEMAP] sonomská, kolize dalšího ostrovníhp oblouku na konci paleozoika [USEMAP] A hick oceanic sequence of Mississippian through Permian chert, limestone, conglomerate, siltstone, shale, lava flows and pyroclastics accumulated in a trough west of the Antler orogenic belt. This tectonic assemblage was emplaced along the Golconda thrust, at least 60 miles (100 km) eastward or inboard of the new continental margin, during the Late Permian through Early Triassic Sonoma Orogeny (Speed, 1983). [USEMAP] Výsledek obrázku pro antler orogeny [USEMAP] Cordilleran orogeny 2561_1413 Cordilleran Orogeny components – Jurassic – Tertiary Periods Nevadan – emplacements of large granite batholiths, Sierra Nevada, Idaho, S. California, Coast Ranges. Sevier – Shallower sub-duction angle = igneous activity moves eastward. Laramide – “Rocky Mts.” – east of Sevier Orogeny –Cretaceous – Tertiary Periods Passive margin Active margin [USEMAP] "Cordilleran" style of arc terrane accretion onto a continental land mass. Continued subduction transports the arc terrane to the margin of the continent where it is too buoyant to be subducted so it gets accreted to the continent [USEMAP] [USEMAP] The Nevadan Orogeny • Several Upper Jurassic Arcs Collided •Cretaceous Franciscan Fm in the accretionary prism • Sierra Nevada was the root zone of the arc The Nevadan Orogeny was a major mountain building event that took place along the western edge of ancient North America between the Mid to Late Jurassic (between about 155 and 145 million years ago). In comparison with other orogenic events, it appears that the Nevadan Orogeny occurred rather quickly (10 million years). During the early stages of orogenesis an "Andean type" continental magmatic arc developed due to subduction of the Farallon oceanic plate beneath the North American Plate. The latter stages of orogenesis, in contrast, saw multiple oceanic arc terranes accreted onto the western margin of North America in a "Cordilleran type" accretionary orogen. Deformation related to the accretion of these volcanic arc terranes is mostly limited to the western regions of the resulting mountain ranges (Klamath Mountain range and Sierra Nevada) and is absent from the eastern regions. The massive series of exposed batholiths that currently make up most of the high Sierra Nevada was formed during this event. Due to the steep angle of the subducted plate, these were located relatively close to continent's edge. [USEMAP] http://www.colorado.edu/geolsci/Resources/WUSTectonics/SierraBatholith/images/location.jpg http://www.colorado.edu/geolsci/Resources/WUSTectonics/SierraBatholith/images/tectonic.jpg [USEMAP] The Franciscan Complex is an assemblage of metamorphosed and deformed sediments and ophiolites, associated with east-dipping subduction zone. Although most of the Franciscan is Early/Late Jurassic through Cretaceous in age (150-66 Ma),[ some Franciscan rocks are as old as early Jurassic (180-190 Ma) age and as young as Miocene (15 Ma). As oceanic crust descended beneath the continent, ocean floor basalt and sediments were subducted and then tectonically underplated to the upper plate.[10] This resulted in widespread deformation with the generation of thrust faults and folding, and caused high pressure-low temperature regional metamorphism. In the Miocene, the Farallon-Pacific spreading center reached the Franciscan trench and the relative motion between Pacific-North America caused the initiation of the San Andreas Fault. [USEMAP] Utah103 C:\Documents and Settings\Eric Cathcart\Desktop\geology of california\nw03_06.gif Evidence for the Nevadan orogeny includes the formation of vast Late Jurassic and Early Cretaceous batholiths (large bodies of igneous rock that formed underground) in southern California, the Sierra Nevada, the Coast Ranges, Idaho, and British Columbia. The name is derived from the changes that occurred in the Sierra Nevada range of eastern California. [USEMAP] Sierra Nevada Mountains 23_11 Nevadan Orogeny: Subduction formed batholith cores of continental volcanic arc, once as tall as Andes [USEMAP] Sevier Orogen (80 Sevier Orogen (50- 130 Ma) • Fold-thrust belt behind the arc • Eastward directed thin skinned thrusts • Franciscan complex and Great Valley fore arc basins • Cretaceous • Batholithic intrusions [USEMAP] Fig. 5 Schematic Late Cretaceous cross-section of the Central Cordillera, showing the relationship between the Sevier fold-and-thrust belt and Cordilleran foreland basin on the east, metamorphic and igneous rocks of the hinterland, Sierra Nevada batholith, Great Valley forearc basin, and Franciscan accretionary complex on the west. [USEMAP] [USEMAP] The Sevier orogeny was the result of convergent boundary tectonic activity, and deformation occurred from approximately 160 million years (Ma) ago to around 50 Ma. This orogeny was caused by the subduction of the oceanic Farallon Plate underneath the continental North American Plate. The Sevier orogeny partially overlapped in time and space with the Laramide orogeny. There is evidence that suggests late Sevier faults were active during the early Laramide. Sevier thrusts may have remained active until the Eocene while Laramide deformation began in the Late Cretaceous In general the Sevier orogeny defines compressional event that took advantage of weak bedding planes in overlying Paleozoic and Mesozoic sedimentary rock. As the crust was shortened, pressure was transferred eastward along the weak sedimentary layers, producing “thin-skinned” thrust faults that generally get younger to the east. In contrast, the Laramide orogeny produced “basement-cored” uplifts that often took advantage of pre-existing faults that formed during rifting in the late Precambrian during the breakup of the supercontinent Rodinia or during the Ancestral Rocky Mountains orogeny [USEMAP] [USEMAP] Location of the Sevier Fold and Thrust Belt (highlighted in red). After Yonkee and Weil (2015) The Sevier Fold and Thrust Belt extends from southern California near the Mexican border to Canada [USEMAP] Figure 3. (A) Generalized geologic map of the Sevier orogenic belt, approximately restored for Cenozoic extension (base map modifi ed from DeCelles, 2004). Mesozoic thrust systems: LFTB—Luning-Fencemaker thrust belt, CNTB—central Nevada thrust belt, ESTB—eastern Sierra thrust belt, WT—Windermere thrust. Structural culminations in Utah: SC— Sevier culmination, CRC—Canyon Range culmination, SAC—Santaquin culmination, WC—Wasatch culmination. Approximate eastern limit of orogenic plateau based on position of Wasatch hingeline and positions of culminations (queried where unknown) (e.g., DeCelles, 1994, 2004; DeCelles and Coogan, 2006). Line A–A′ delineates approximate crosssection line of Figure 4A. Note that exhumation magnitudes outside of the map area in this study are not quantifi ed. Luning-Fencemaker fold and thrust belt was active from the Middle or Late Jurassic through the. Early Cretaceous – Nevadan orogeny [USEMAP] Figure 4. Schematic cross sections comparing deformation geometries and exhumation patterns between the Sevier and central Andean orogenic systems. Approximate cross-section lines are shown in Figure 3. (A) Schematic preextensional geometry of the Sevier orogenic system, modifi ed from Allmendinger et al. (1987) and Best et al. (2009). Placements of individual structures and plutons are largely schematic, and are meant to show only general locations. Eastern limit of high topography is placed above the Canyon Range culmination (DeCelles and Coogan, 2006). Generalized exhumation magnitudes are shown by red and orange bars. LFTB—Luning-Fencemaker thrust belt, CNTB—central Nevada thrust belt, SC—Sevier culmination, CRC—Canyon Range culmination, DWC—Delamar–Wah Wah– Canyon Range, Z–Pz—Neoproterozoic–Paleozoic. (B) Schematic present-day geometry of the central Andean orogenic system (modifi ed from Leier et al., 2010). Generalized exhumation magnitudes are shown by red and yellow bars. Pz–Mz—Paleozoic–Mesozoic. [USEMAP] ~210 Ma on the east side of the batholith in a single, extensive Triassic sequence 186-155 Ma on both east and west margins of the batholith 125-88 Ma granitoids, which young eastward, in the axial part of the batholith [USEMAP] Výsledek obrázku pro Franciscan accretionary prism [USEMAP] Fig. 8.5 Cross sections of the forearc region. Upper: general cross section of typical Cordilleran margin showing tectonic and sedimentary elements and geomorphic settings. Lower: details of forearc setting typical of the Late Jurassic through Paleocene of Central California showing tectonic and sedimentary setting of Franciscan and Great Valley sedimentary rocks. Light tan shows zones of active sedimentation. Note that most Franciscan deposits are bathyal to abyssal and that Great Valley deposits range from shoreline to abyssal. The contact between Franciscan and Great Valley rocks is everywhere tectonic – usually the Coast Range Fault zone. Queried areas have uncertain relations. Over long periods of geologic time, the entire forearc region became new continental crust added to western North America; Cenozoic sedimentary basins and associated volcanic rocks were developed across the forearc region during the ensuing compressional, transpressional, and transform tectonic regimes (Modified after Frisch et al. 2011) [USEMAP] WICHG31411e Franciscan complex – a Late Jurassic/Early Cretaceous chaotic mixture of graywacke, volcanic breccia, siltstone, black shale, chert, pillow-basalt, and blueschist (a low temperature, high pressure metamorphic rock) resulting from the “scraping-off” of continental shelf, cont. slope, and deep sea sediments from the Farallon Plate. [USEMAP] Sevier thin-skinned deformation 23_12 b [USEMAP] http://higheredbcs.wiley.com/legacy/college/levin/0471697435/chap_tut/images/nw0300-nnc.jpg Competent (resistant to flow) ~50 Ma: End of subduction •In the Cenozoic, the slab became completely horizontal, probably due to progressive decrease in age of the subducting Farallon Plate as the ridge approached the trench. Results include end of calc-alkaline volcanism, major compressive orogeny far inland (Laramide orogeny of the Rocky Mountains) and emplacement of Pelona and related schists under Southern California 44 [USEMAP] [USEMAP] [USEMAP] Laramide Orogeny (50- 80 Ma) •Late Cretaceous - Early Eocene •Deformation shifted eastward following •Magmatism – Coast Range Arc •Thick-skinned tectonics The Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. The major feature that was created by this orogeny was deep-seated, thick-skinned deformation, with evidence of this orogeny found from Canada to northern Mexico. Most hypotheses propose that the angle of subduction became shallow. The Laramide Orogeny lasted about 30 million years during which the Rocky Mountain foreland ranges were pushed up. The area affected by the Laramide Orogeny includes the central and southern Rockies and the Colorado Plateau. Magmatism associated with subduction occurred not near the plate edges (as in the volcanic arc of the Andes, for example), but far to the east, called the Coast Range Arc. Coast Range Arc is the largest granitic outcropping in North America, which then it is usually referred to as the Coast Plutonic Complex or the Coast Mountains Batholith [USEMAP] The Laramide orogeny was caused by subduction of a plate at a shallow angle. The Laramide Orogeny lasted about 30 million years during which the Rocky Mountain foreland ranges were pushed up. The area affected by the Laramide Orogeny includes the central and southern Rockies and the Colorado Plateau. [USEMAP] The Three Patriarchs in Zion Canyon are made of Navajo Sandstone. It may originate from the Late Triassic but is at least as young as the Early Jurassic stages Pliensbachian and Toarcian [USEMAP] deformation landward of the relatively undeformed Colo- rado Plateau [USEMAP] [USEMAP] laramide_slab Humphreys et al., 2003 [USEMAP] [USEMAP] Buoyant Subduction Laramide Orogeny 23_14 Normal, thin-skinned Vertical block uplift Approaching Continent pushes accretionary wedge sediments into forearc sediments Now we understand weird looking Tetons [USEMAP] The Coast Range Arc formed as a result of subduction of the Juan de Fuca, Kula and pre-existing Farallon Plates. It is most famous for being the largest granitic outcropping in North America, which then it is usually referred to as the Coast Plutonic Complex or the Coast Mountains Batholith. Although taking its name from the Coast Mountains, this term is a geologic grouping rather than a geographic one, and the Coast Range Arc extended south into the High Cascades of the Cascade Range, past the Fraser River which is the northward limit of the Cascade Range proper. [USEMAP] [USEMAP] As the Insular Volcanic Islands collided with the Pacific Northwest, the old subduction zone of the Insular Plate jammed and shut down entirely. The descending Farallon Plate took over as the active subduction zone. As molten rock from the Farallon Plate rose upward through the accreted Insular Belt, the Coast Range Arc intruded molten granitic rocks to form the Coast Range Mountains from Washington to Alaska. [USEMAP] Image of the Pacific Northwest. Red indicates the inferred boundaries of the Coast Range Arc. [USEMAP] The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades. The highest peak in the range is Mount Rainier in Washington at 14,411 feet (4,392 m). [USEMAP] Tertiary Postlaramide evolution ÜFaralon plate subducted ÜTangential motion and expansion replaced convergent motion as the North American plate began interacting with the Pacific plate. ÜThe San Andreas Fault system was formed ÜWidespread magmatism and volcanism ÜBasin and Range extension [USEMAP] M:\History.gif [USEMAP] Modern California: Strike-Slip tectonics •There is evidence of strike-slip motion across the surface rupture of the 1872 Lone Pine earthquake. This air-photo of the San Andreas Fault shows a somewhat clearer offset drainage. •On the other hand, California is also a transform plate boundary zone, which is accommodated be a series of strike-slip faults. 63 [USEMAP] The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating between narrow faulted mountain chains and flat arid valleys or basins. The physiography of the province is the result of tectonic extension that began around 17 million years ago in the early Miocene epoch. This province is literally being split apart by tension connected with magmatism along the Nevada–Columbia Basin magmatic belt which was generated above an elongated sublithospheric melt zone associated with arrival of the Yellowstone mantle plume- —a region of the mantle that is hot but still solid and that is buoyantly upwelling [USEMAP] The Nevada–Columbia Basin magmatic belt, a linear zone of dikes and basaltic volcanic centers that extends for >1000 km, from southern Nevada to the Columbia Basin of eastern Washington. [USEMAP] [USEMAP] Figure 5. Cross section of the Basin and Range Province. The gray rectanglar outline represents the area traversed by the Virgin River Gorge. Thin curved black lines represent faults. Modified from USGS cross section. This province is literally being split apart by tension resulting from a source of heat energy that exists below the region. Evidence for that heat is provided by numerous volcanoes and lava flows scattered throughout this province. The term “Basin and Range” comes from the generally parallel north-trending mountains (the ranges) separated by valleys (the basins). Rocks in each of these mountain ranges are tilted and bounded by faults and are thus described as fault block mountains. Our Geological Wonderland: The geology of the Virgin River Gorge can be considered to be a geological example of the rabbit hole in “Alice in Wonderland.” [USEMAP] [USEMAP] [USEMAP] Yellowstone National Park Grand Prismatic Spring Old Faithful Nachází se zde velké množství horkých pramenů, bublajících bahnitých jam, horských jezer, kaňonů, erodovaných lávových proudů a gejzírů. Nejznámějším gejzírem je Old Faithful, jenž tryská průměrně po 64,5 minutách do výšky 40 m, maximálně pak až do výšky 56 m. Takto vytryskuje asi 120 let. [USEMAP] Franklinsko – inuitská orogeneze Při severním okraji severoamerického kratonu probíhala ve spodním paleozoiku ellesmerská a inuitská orogeneze. Dostupné údaje zatím neumožňují jjeich jednoznačnou interpretaci.