Sierra Madre Occidental Information
The Sierra Madre Occidental is a mountain range in western Mexico. Sierra Madre means "Mother Range". The range extends from near the Arizona border down to the Sierra Madre del Sur. This range is primarily an igneous formation. The relief caused by this rise has created a unique ecosystem that makes a forest viable in the area, causing habitat that is unique to this range.
This forest and canyon land provided a place for a variety of indigenous people to live, until spanish settlers came into the area to found towns for the silver mines in the area. The major industry in the area now are argriculture and forestry, which have become contentious becuase of preceived land degradation and the native population's fight against this.
Contents |
Geography
Copper Canyon in Chihuahua, Mexico Basaseachic FallsThe range runs north to south, from just south of the Sonora–Arizona border southeast through eastern Sonora, western Chihuahua, Sinaloa, Durango, Zacatecas, Nayarit, Jalisco, Aguascalientes to Guanajuato, where it joins with the Sierra Madre del Sur and the Eje Volcánico Transversal (Transverse Volcanic Axis) of central Mexico. These mountains are generally considered to be part of the much larger American cordillera, the mountains extending from Alaska down to these across Western North America.[1]
This is a dramatic landscape of steep mountains formed by a high plateau that has been cut through with canyons including Copper Canyon, larger and, in places, deeper than the Grand Canyon.[2] The highest point is probably Cerro Mohinora, located at 25°57′N 107°03′W / 25.95°N 107.05°W The height of the mountain ranges from estimates of 3,040 m (9,970 ft) [3] up to 3,300 m (10,800 ft).[4] However, other mountains at 26°03′N 106°25′W / 26.05°N 106.417°W and 23°12′N 104°57′W / 23.2°N 104.95°W are of very similar altitude and may be higher.
Geology
The Sierra Madre Occidental is a high plateua of volcanic rock that is eroded in areas to reveal a basement composed of plutonic and sedimentary rocks underlying the two groups of extrusive volacanics.[5] Some intrusions in the area have deposited ore veins that are commercially viable.
Basement
The basement rock in the area is composed of metamorphised formations that show no signs of the volcanism that would later come to characterize the area. This formation is primarily composed of granite, gneiss, and schist in the North, with a slightly younger metamorphised clastic sedimentary and volcanic schist in the South.[6] After the metamorphosed basement, marine sedimentary rocks form the majority of the rock. Local exporsure of Argillite and Limestone is present in localized deposits.[7] Following these deposits continental based clastic sedimentary formantions occur with shallow marine and some volcanic rocks.
Early Magmatism
Towards the end of the Cretaceous, magmatism in the area became more active. This led to the formation of pultonic and volcanic rock, which would later be exposed. Interbedded with these rocks are sedimentary deposit rocks. In the center of the range, some of these rock have been deformed by tectonic action that occurred at the same time. The southern part of the range contains none of the volcanism that is apparent in the northern range. These formations ended in the Paleocene.[6] Eocene volcanism formed a series of andesitic and rhyolitic formations in the area, with spatial and temporal variations throughout. These rocks also have intrusions that form the majority of the gold and silver deposits in the area.[8]
Later Magmatism
In the Oligocene ash flows became the predominate the formation of the area, with interbedded lava flows between. Units are a series of ignimbrite formations layered one atop another, that are sometimes broken by lava flows.[9] This ignimbrite formations in this area cover the largest area of any known series, with ten caldera identified in the province.[10] Three of these calderas are placed in Copper Canyon. The lava has formed a series of mafic rock that form the Southern Cordilleran Basaltic Andesite Suite.[11] The tuffs are above a thick formation of lava rock. Around five or six units have been identified, mostly around the Copper Canyon area. These tuffs have actually allowed wide ranging correlation with formations in other geographical areas, for example Death Valley.[12]
Climate
The climate varies considerably between the northern and southern extents of this long mountain range. Seasonal variations also occur due to the presence of large bodies of warm water delivering warm damp air from each side of the range. This region undergoes a seasonal variety with two wet and two dry seasons each year.
Rainfall
Monsoon rains come to the Sierra Madre in June. This follows the movement of a typically developed high pressure area north from the mountains to New Mexico during this time. This causes east winds bringing moisture from the Gulf of Mexico. Rainfall from the monsoon is especially focused on the mountainous regions causing 10 to 15 inches of rain.[13] The southern region receives more of the rainfall than the northern. On the western side of the mountains rainfall can exceed 30 cm (12 in) in a single month. Much of this of this percipitation occurs as tropical storms. The high pressure begins to break down in Spertember or October. Because of the monsoon, the summer accounts for the majority of rainfall in the area.[14] The spring and fall dry season separate out a weaker wet season in the winter. In addition to increasing in the southern ranges of the mountains, rainfall increases in the higher elevations of the Sierra Madre Occidental.[14]
Temperature
The climate in the mountains is mild with freezing temperatures in the winter limited to the high peaks and summer temperatures maintaining a constant level. Maximum temperatures are typically in July at around 31 C[15] with average temperatures on the order of 16 C during this same period.[14] Below freezing temperatures can occur in the higher mountains, with precipatation occuring as snowfall certain times of year.[16]
Water
Rivers of the mountains include the Río Grande de Santiago, which drains 100000 km^2 from the Southern Slopes of the Sierra Madre,[17] and the Humaya River in Sinaloa. Due to the continued logging in the area, erosion on the slopes of hillsides has increased.[18]
Ecology
The Sierra Madre Occidental pine-oak forests are found at elevations of 1,500–3,000 m (4,900–9,800 ft) throughout the range.[19]
Oaks dominate the lower reaches of the mountains, with stands down to about 1,000 m (3,300 ft). Some oak species even continue into the surrounding ecosystems.[20] At higher elevations pines begin to grow alongside the oaks, with pines dominating the oaks at higher elevations.[21] At high elevations and in the north Mixed Conifer Forests become the dominate ecosystem. The high mountain tops may also be grasslands surrounded by the forest that occur in those areas.
The Sonoran Desert is found in the northwestern foothills at 1,000–2,000 m (3,300–6,600 ft).[22] The Chihuahuan Desert is found to the northeast and east, the Meseta Central matorral and Central Mexican matorral to the southeast, and the Sinaloan dry forests to the west and southwest. This ecoregion is noted for its high biodiversity and large number of endemic species.
Preservation efforts in the modern day, include those from Edwin Bustillos.[23] Other groups work to protect animal species in the area including Conservation International.[24]
People and History
The mountains are home to several indigenous nations speaking Uto-Aztecan languages, including the Tarahumara in the central portion of the range, and the Huichol in the southern part of the range.
Spanish Sierra Madre
Early Spanish influence in the area came from the new silver mines, the first of which was established in 1567 at Santa Barbara.[25] During the missionary years that came as the mines developed, opposition to the missionaries built up, leading to the Tepehuán Revolt. This revolt began in 1616 in the town of Santa Catalina in Durango.[26] Revolts would follow with the last major revolt beginning March 1690 among the Tarahumara ending in 1698.[27] After the Apache faced heightened resistance to raiding from the Spanish in Chihuahuan, they moved down to the Sierra Madre in 1794.[28]
Mexican Sierra Madre
After 1886, these mountains served as refuge for the remaining Chiricahua Apache known as the Nameless Ones (Nnee Nnaahí) who refused to surrender with Geronimo to U.S. forces.
Railroads came to the area starting in the 1880s and 1890s, which allowed many old mines in the region to reopen at a profit.[29] Loggers began arriving in the mountains in the late 1800s. In response to the new industry, the Tarahumara moved further into the canyons. The mountain range was crossed by the Ferrocarril Chihuahua al Pacifico railroad completed 1962.[18] The railroad went up for sale in 1996, but no transaction was ever completed.[30]
References
- ^ Hildebrand, Robert. ""Did westward subduction cause Cretaceous - Tertiary orogeny in the North American Cordillera"". http://dandelion-patch.mit.edu/afs/athena.mit.edu/course/12/12.115/OldFiles/www/12.114%20Papers/HILDEBRAND_GSA_SP_FINAL_WHOLE.pdf.
- ^ "Mexico's Copper Canyon". 2012. http://www.wildernessinquiry.org/destinations/index.php?dest=coppercanyon.
- ^ Mathiasen (2010). "First Report of White Fir Dwarf Mistletoe (Arceuthobium abietinum f. sp. concoloris) on Mexican Spruce (Picea mexicana) in Northern Mexico". http://openagricola.nal.usda.gov/Record/IND44357752.
- ^ Valenzuela, Luis. "Going back to my roots". http://www.personal.psu.edu/lrv110/index_files/Page371.htm.
- ^ ""Geology"". Bronco Gold and Silver. http://broncogold.com/geology.html.
- ^ a b Ferrari, Luca; Valencia-Moreno, Martin; Bryan, Scott (2007). ""Magmatism and tectonics of the Sierra Madre Occidental and its relation with the evolution of the western margin of North America"". Geological Society of America.
- ^ Ferrari, Luca; Pasquare, Giorgio; Venegas-Salgado, Saul; Romero-Rios, Francisco (1999). ""Geology of the western Mexican Volcanic Belt and adjacent Sierra Madre Occidental and Jalisco Block"". "Geological Society of America".
- ^ McDowell, Fred; Clabaugh, Stephen (1981). "Igneous History of the Sierra Madre Occidental". http://www.rmcg.unam.mx/5-2/(6)McDowell.pdf.
- ^ Swanson, Eric; Kempter, Kirt; McDowell, Fred; McIntosh, William (7 March 2006). ""Major ignimbrites and volcanic centers of the Copper Canyon area: a view into the core of Mexico's Sierra Madre Occidental"". Gelogical Society of America.
- ^ Aguirre-Diaz, Gerardo; Labarthe-Hernandez, Guillermo; Torres, Ramon (2002). "Basin and Range Fissure-Source Origin for Voluminous Ignimbrites of the Sierra Madre Ocidental, Mexico". http://gsa.confex.com/gsa/2002CD/finalprogram/abstract_34577.htm.
- ^ Swanson, Eric (2002). "Correlation between the Tomochic and Copper Canyon Areas, the Sierra Madre Occidental, Chihuahua, Mexico". http://gsa.confex.com/gsa/2002SC/finalprogram/abstract_33078.htm.
- ^ Knott, J.R.; Sarna-Wojcicki, A.M.; Machette, M.N.; Klinger, R.E. (2005). "Upper Neogene Stratigraphy and Tectonics of Death Valley – a review". http://geology.fullerton.edu/jknott/images/ESR%20Paper.pdf.
- ^ "The North American Monsoon". National Weather Service.
- ^ a b c Heyerdahl, Emily; Alvarado, Ernesto (2003). ""Influence of Climate and Land Use on Historical Surface Fires in Pine-Oak Forests, Sierra Madre Occidental, Mexico"". http://www.fs.fed.us/rm/pubs_other/rmrs_2003_heyerdahl_e001.pdf.
- ^ Garatuza-Payan, Jaime; Pinker, Rachel; Watts, Christopher (Dec 2001). "Solar radiation and évapotranspiration in northern Mexico estimated from remotely sensed measurements of cloudines".
- ^ "Sierra Madre Occidental pine-oak forests". 1 Dec 2006. http://www.eoearth.org/article/Sierra_Madre_Occidental_p.
- ^ Cisneros, Ruben (2011). "Provenance and Origin of Holocene Beach Ridge and Modern Beach Sands from the Costa de Nayarit, Western Mexico". http://etd.lsu.edu/docs/available/etd-04262011-150353/unrestricted/Ruben_Cisneros_THESIS_FINAL_DRAFT_GRAD_SCHOOL.pdf.
- ^ a b ""Mexican Deforestation in the Sierra Madre"". 1996. http://www1.american.edu/ted/MEXDEFOR.HTM.
- ^ "Sierra Madre Occidental pine-oak forests (NA0302)". WWF Full Reports. World Wide Fund for Nature. http://www.worldwildlife.org/wildworld/profiles/terrestrial/na/na0302_full.html. Retrieved 2010-10-10.
- ^ "Center for Sonoran Desert Studies". 2006. http://www.desertmuseum.org/programs/alamos_vegetation.htm.
- ^ "Major Biotic Communities". http://www.biopark.org/sierramadre.html.
- ^ ""Sonoran desert (NA1310)"". WWF Full Reports. World Wide Fund for Nature. http://www.worldwildlife.org/wildworld/profiles/terrestrial/na/na1310_full.html. Retrieved 2010-10-10.
- ^ Edwin Bustillos "Goldman Environmental Prize". http://www.goldmanprize.org/node/87 Edwin Bustillos.
- ^ "Sierra Madre de Chiapas". Conservation International. http://www.conservation.org/where/north_america/mexico/pages/sierra_madre_de_chiapas.aspx.
- ^ schmal, John (2004). "Indigenous Chihuahua: a Story of War and Assimilation". http://www.houstonculture.org/mexico/chihuahua.html.
- ^ ""The Black Robes of New Spain"". "American Catholic Historical Association". 29 Dec 1934.
- ^ Schroeder, Susan. “Native resistance and the Pax Colonial in New Spain”.
- ^ Rushforth, Scott (July 2010). "“Ethnographic overview and assessment of Chiricahua National Monument and Fort Bowie National Historic Site”". http://www.cefns.nau.edu/Orgs/CPCESU/current/documents/NMSUCP-007FinalReport.pdf.
- ^ Knight, Alan (1986). The Mexican Revolution: Counter-revolution and Reconstruction.
- ^ Campos, Javier (2000). ""Access issues in Latin America railroads: what could Europe learn/avoid?"". http://www.vatt.fi/file/vatt_publication_pdf/k245.pdf#page=213.
| Wikimedia Commons has media related to: Sierra Madre Occidental |
|
|||||||
| This Mexico-related article is a stub. You can help Wikipedia by expanding it.
|
Categories:
- Sierra Madre Occidental
- Mountain ranges of Mexico
- Mountain ranges of the Sonoran Desert
- Mountain ranges of Sonora
- Geography of Chihuahua
- Geography of Durango
- Geography of Zacatecas
- Physiographic provinces
- Northwestern Mexico
- Regions of Northern Mexico
|