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San Martin Volcano
The isolated San Martin Tuxtla volcano is a shield volcano which rises above the Gulf of Mexico. It has had eruptions in historical times. It occurs in the Tuxtla volcanic field in Veracruz, Mexico. Lavas from San Martin vary between basanite and alkali basalt. Locally the volcano is also known as Tiltépetl (Black Mountain in the Nahuatl language). Morphology San Martin forms a broad shield volcano, it rises to a height of 1680 m and is capped by a 1 km wide summit crater which is 150 m in depth. The crater contains two pyroclastic cones that were the source of the large 1793 eruption. The flanks of the volcano are dotted with 250 pyroclastic cones and maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...s, some of which have been active in historical times. The volcano is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of Mexico
The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southwest and south by the Mexican states of Tamaulipas, Veracruz, Tabasco, Campeche, Yucatán, and Quintana Roo; and on the southeast by Cuba. The coastal areas along the Southern U.S. states of Texas, Louisiana, Mississippi, Alabama, and Florida, which border the Gulf on the north, are occasionally referred to as the "Third Coast" of the United States (in addition to its Atlantic and Pacific coasts), but more often as "the Gulf Coast". The Gulf of Mexico took shape about 300 million years ago (mya) as a result of plate tectonics. The Gulf of Mexico basin is roughly oval and is about wide. Its floor consists of sedimentary rocks and recent sediments. It is connected to part of the Atlantic Ocean through the Straits of Florida between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundary, maritime boundaries with the Pacific Ocean to the west, the Caribbean Sea to the southeast, and the Gulf of Mexico to the east. Mexico covers 1,972,550 km2 (761,610 sq mi), and is the List of countries by area, thirteenth-largest country in the world by land area. With a population exceeding 130 million, Mexico is the List of countries by population, tenth-most populous country in the world and is home to the Hispanophone#Countries, largest number of native Spanish speakers. Mexico City is the capital and List of cities in Mexico, largest city, which ranks among the List of cities by population, most populous metropolitan areas in the world. Human presence in Mexico dates back to at least 8,000 BC. Mesoamerica, considered a cradle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shield Volcano
A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano. Repeated eruptions result in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form. Shield volcanoes are found wherever fluid, low-silica lava reaches the surface of a rocky planet. However, they are most characteristic of ocean Volcanic island, island volcanism associated with Hotspot (geology), hot spots or with Rift, continental rift volcanism. They include the largest active volcanoes on Earth, such as Mauna Loa. Giant shield volcanoes are found on other planets of the Solar System, including Olympus Mons on Mars and Sapas Mons on Venus. Etymology The term 'shield volcano' is taken from the German term ''Schildvulkan'', coined by the Austrian geologist Eduar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierra De Los Tuxtlas
The Sierra de Los Tuxtlas (Tuxtlas Mountains) are a volcanic belt and mountain range along the southeastern Veracruz Gulf of Mexico, Gulf coast in Eastern Mexico. The Biósfera Los Tuxtlas, Los Tuxtlas Biosphere Reserve (Biósfera Los Tuxtlas) includes the coastal and higher elevations of the Sierra de Los Tuxtlas. The volcanic mountains were used as a basalt source by the Olmec culture during the Formative stage, Early Formative period (). Quarried basalt was transported by raft through a network of rivers, to sites in the Olmec heartland for use in creating monuments, including Olmec colossal heads, colossal heads. Geography Peaks in this range include Volcano Santa Marta and San Martin Tuxtla, Volcano San Martín Tuxtla, both rising above 1,700 meters. San Martín Tuxtla is the only recently active volcano in the belt, erupting in 1664 and again in May 1793. It is a broad alkaline shield volcano with a one kilometer wide summit. Hundreds of smaller cinder cones are prevalent t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veracruz
Veracruz, formally Veracruz de Ignacio de la Llave, officially the Free and Sovereign State of Veracruz de Ignacio de la Llave, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entities of Mexico. Located in eastern Mexico, Veracruz is bordered by seven states, which are Tamaulipas, San Luis Potosí, Hidalgo (state), Hidalgo, Puebla, Oaxaca, Chiapas, and Tabasco. Veracruz is divided into Municipalities of Veracruz, 212 municipalities, and its capital city is Xalapa, Xalapa-Enríquez. Veracruz has a significant share of the coastline of the Gulf of Mexico on the east of the state. The state is noted for its mixed ethnic and indigenous populations. Cuisine of Veracruz, Its cuisine reflects the many cultural influences that have come through the state because of the importance of the port of Veracruz (city), Veracruz. In addition to the capital city, the state's largest cities include Veracruz, Coatzacoalcos, Córdoba, V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basanite
Basanite () is an igneous, volcanic ( extrusive) rock with aphanitic to porphyritic texture. It is composed mostly of feldspathoids, pyroxenes, olivine, and calcic plagioclase and forms from magma low in silica and enriched in alkali metal oxides that solidifies rapidly close to the Earth's surface. Description Basanite is an aphanitic (fine-grained) igneous rock that is low in silica and enriched in alkali metals. Of its total content of quartz, feldspar, and feldspathoid ( QAPF), between 10% and 60% by volume is feldspathoid and over 90% of the feldspar is plagioclase. Quartz is never present. This places basanite in the basanite/ tephrite field of the QAPF diagram. Basanite is further distinguished from tephrite by having a normative olivine content greater than 10%. While the IUGS recommends classification by mineral content whenever possible, volcanic rock can be glassy or so fine-grained that this is impractical, and then the rock is classified chemically using the TA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali Basalt
Alkali basalt or alkali olivine basalt is a dark-colored, porphyritic volcanic rock usually found in oceanic and continental areas associated with volcanic activity, such as oceanic islands, continental rifts and volcanic fields. Alkali basalt is characterized by relatively high alkali (Na2O and K2O) content relative to other basalts and by the presence of olivine and titanium-rich augite in its groundmass and phenocrysts, and nepheline in its CIPW norm. Geochemical characterization Alkali basalt is chemically classified as a rock in region B (basalt) of the total alkali versus silica (TAS) diagram that contains nepheline in its CIPW norm. Basalts that do not contain normative nepheline are characterized as sub-alkali basalts, which include tholeiitic basalts and calc-alkaline basalts. Petrography The groundmass of alkali basalt is mainly composed of olivine, titanium-rich augite and plagioclase feldspar and may have alkali feldspar or feldspathoid interstitially, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Cone
Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include stratocones, spatter cones, tuff cones, and cinder cones. Stratocone Stratocones are large cone-shaped volcanoes made up of lava flows, explosively erupted pyroclastic rocks, and igneous intrusives that are typically centered around a cylindrical vent. Unlike shield volcanoes, they are characterized by a steep profile and periodic, often alternating, explosive eruptions and effusive eruptions. Some have collapsed craters called calderas. The central core of a stratocone is commonly dominated by a central core of intrusive rocks that range from around to over several kilometers in diameter. This central core is surrounded by multiple generations of lav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maar
A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow crater lake, which may also be called a maar.David S.G. Thomas and Andrew Goudie (eds.), ''The Dictionary of Physical Geography'' (Oxford: Blackwell, 2000), 301. . Maars range in size from across and from deep. Most maars fill with water to form natural lakes. Most maars have low rims composed of a mixture of loose fragments of volcanic rocks and rocks torn from the walls of the diatreme. Etymology The name ''maar'' comes from a Moselle Franconian dialect word used for the circular lakes of the Daun area of Germany. The word evolved from its first use in German in the modern geological sense in 1819 and is now used in English and in the geological sciences as the term for the explosion crater, even if water from rainfall might alway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Tuxtlas
Los Tuxtlas is a region in the south of the Mexican state of Veracruz. Politically it refers to four municipalities: Catemaco, San Andrés Tuxtla, Santiago Tuxtla and Hueyapan de Ocampo. It also refers to a high complex natural ecosystem, an isolated volcanic mountain range next to the Gulf of Mexico, home to the northern edge of tropical rainforest in the Americas. Although seriously deforested, most of it is under protection as the Los Tuxtlas Biosphere Reserve, which stretches over eight municipalities, centering on the four mentioned above. The area's early history was influenced by the Olmecs but had its own trajectory. In the colonial period, the population became a mix of indigenous, Afro-Mexican, African and European. For all its history until the present, it has been rural and agricultural. Today one of its notable crops is tobacco. However, conservation efforts since the 1970s have promoted ecotourism, especially in Catemaco. Geography and environment Topography The S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene Shield Volcanoes
The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing Ice age, glacial cycles of the Quaternary, and is equivalent to Marine isotope stages, Marine Isotope Stage 1. The Holocene correlates with the last maximum axial tilt towards the Sun of the Earth#Axial tilt and seasons, Earth's obliquity. The Holocene corresponds with the rapid proliferation, growth, and impacts of the human species worldwide, including Recorded history, all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban culture, urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global significance for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
