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Mount Jefferson (Oregon)
Mount Jefferson is a stratovolcano in the Cascade Volcanoes, Cascade Volcanic Arc, part of the Cascade Range in the U.S. state of Oregon. The second highest mountain in Oregon, it is situated within Linn County, Oregon, Linn County, Jefferson County, Oregon, Jefferson County, and Marion County, Oregon, Marion County and forms part of the Mount Jefferson Wilderness. Due to the ruggedness of its surroundings, the mountain is one of the hardest volcanoes to reach in the Cascades. It is also a popular tourist destination despite its remoteness, with recreational activities including hiking, backpacking (wilderness), backpacking, mountaineering, and photography. Vegetation at Mount Jefferson is dominated by Douglas fir, Abies amabilis, silver fir, mountain hemlock, ponderosa pine, lodgepole pine, and several Cedar wood, cedar species. Carnivores, insectivores, bats, rodents, deer, birds, and various other species inhabit the area. Also known as Seekseekqua by Native American populati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three Fingered Jack
Three Fingered Jack is a summit of a shield volcano of the Cascade Range in the U.S. state of Oregon. Formed during the Pleistocene Epoch (geology), epoch, the mountain consists mainly of basaltic andesite lava and was heavily glacier, glaciated in the past. While other Oregon volcanoes that were heavily glaciated—such as Mount Washington (Oregon), Mount Washington and Mount Thielsen—display eroded Volcanic plug, volcanic necks, Three Fingered Jack's present summit is a comparatively narrow ridge of loose tephra supported by a dike (geology), dike only thick on a generally north–south axis. Glaciation exposed radiating dikes and plugs that support this summit. The volcano has long been inactive and is highly eroded. Three Fingered Jack has diverse flora, fauna, and fungi. The Molala people, one of the Indigenous peoples of the Northwest Plateau, indigenous groups in the northwestern United States, historically inhabited the area around the volcano. Not much is known abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abies Amabilis
''Abies amabilis'', commonly known as the Pacific silver fir, is a fir native to the Pacific Northwest of North America, occurring in the Pacific Coast Ranges and the Cascade Range. It is also commonly referred to as the white fir, red fir, lovely fir, Amabilis fir, Cascades fir, or silver fir. The species name is Latin for 'lovely'. Description The tree is a large evergreen conifer growing to , exceptionally tall, and with a trunk diameter of up to , exceptionally . The bark on younger trees is light grey, thin and covered with resin blisters. On older trees, it darkens and develops scales and furrows. The leaves are needle-like, flattened, long and wide by thick, matte dark green above, and with two white bands of stomata below, and slightly notched at the tip. The leaf arrangement is spiral on the shoot, but with each leaf variably twisted at the base so they lie flat to either side of and above the shoot, with none below the shoot. The shoots are orange-red with dense v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andesite
Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende. Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. Along with basalts, andesites are a component of the Martian crust. The name ''andesite'' is derived from the Andes mountain range, where this rock type is found in abundance. It was first applied by Christian Leopold von Buch in 1826. Description Andesite is an aphanitic (fine-grained) igneous rock that is intermediate in its content of silica and low in alkali metals. It has less than 20% quartz and 10% feldspathoid by volume, with at least 65% of the fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basaltic Andesite
Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central America and the Andes of South America. Description Basaltic andesite is a fine-grained (aphanitic) igneous rock that is moderately low in silica and low in alkali metal oxides. It is not separately defined in the QAPF classification, which is based on the relative percentages of quartz, alkali feldspar, plagioclase feldspar, and feldspathoids, but would fall in the basalt-andesite field. This corresponds to rock in which feldspathoid makes up less than 10% and quartz less than 20% of the total QAPF fraction, and in which at least 65% of the feldspar is plagioclase. Basaltic andesite would be further distinguished from basalt and andesite by a silica content between 52% and 57%. Although classification by mineral content is preferred by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific Plate (which borders the plate to the west). It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust. The interior of the main continental landmass includes an extensive granitic core called a craton. Along most of the edges of this craton are fragments of crustal material called terranes, which are accreted to the craton by tectonic actions over a long span of time. It is thought that much of North America west of the Rocky Mountains is composed of such terranes. Boundaries The southern boundary with the Cocos Plate to the west and the Caribbean Plate to the east is a transform fault, represented by the Swan Islands Transform Fault unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Subduction is possible because the cold oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle underlying the cold, rigid lithosphere. Once initiated, stable subduction is driven mostly by the negative buoyancy of the de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatexis
Anatexis (via Latin from Greek roots meaning "to melt down") is the partial melting of rocks. Traditionally, anatexis is used specifically to discuss the partial melting of crustal rocks, while the generic term "partial melting" refers to the partial melting of all rocks, in both the crust and mantle. Anatexis can occur in a variety of different settings, from zones of continental collision to mid-ocean ridges. It is believed that anatexis is the process largely responsible for the formation of migmatites. Furthermore, scientists have recently discovered that partial melting plays an increasingly important role in active crustal processes, including the advancement of active deformation and the emplacement of crustal granites. As a result, active feedback between crustal shearing, melting, and granite emplacement has become largely accepted in the place of large scale, unreasonable models involving fractional melting of the mantle into granitic batholiths and plutons. Evidence f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Jefferson
Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, philosopher, and Founding Fathers of the United States, Founding Father who served as the third president of the United States from 1801 to 1809. He was previously the nation's second vice president of the United States, vice president under John Adams and the first United States Secretary of State, United States secretary of state under George Washington. The principal author of the United States Declaration of Independence, Declaration of Independence, Jefferson was a proponent of democracy, republicanism, and individual rights, motivating Thirteen Colonies, American colonists to break from the Kingdom of Great Britain and form a new nation. He produced formative documents and decisions at state, national, and international levels. During the American Revolution, Jefferson represented Virginia in the Continental Congress that adopted the Declaration of Independence. As ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insectivore
A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores were amphibians. When they evolved 400 million years ago, the first amphibians were piscivores, with numerous sharp conical teeth, much like a modern crocodile. The same tooth arrangement is however also suited for eating animals with exoskeletons, thus the ability to eat insects is an extension of piscivory. At one time, insectivorous mammals were scientifically classified in an order called Insectivora. This order is now abandoned, as not all insectivorous mammals are closely related. Most of the Insectivora taxa have been reclassified; those that have not yet been reclassified and found to be truly related to each other remain in the order Eulipotyphla. Although individually small, insects exist in enormous numbers. Insects make u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivore
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other soft tissues) whether through hunting or scavenging. Nomenclature Mammal order The technical term for mammals in the order Carnivora is ''carnivoran'', and they are so-named because most member species in the group have a carnivorous diet, but the similarity of the name of the order and the name of the diet causes confusion. Many but not all carnivorans are meat eaters; a few, such as the large and small cats (felidae) are ''obligate'' carnivores (see below). Other classes of carnivore are highly variable. The Ursids, for example: While the Arctic polar bear eats meat almost exclusively (more than 90% of its diet is meat), almost all other bear species are omnivorous, and one species, the giant panda, is nearly exclusively herbivorous. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cedar Wood
Cedar is part of the English common name of many trees and other plants, particularly those of the genus ''Cedrus''. Some botanical authorities consider the Old-World ''Cedrus'' the only "true cedars". Many other species worldwide with similarly aromatic wood, including several species of genera ''Calocedrus'', ''Thuja'', and '' Chamaecyparis'' in the Pacific Northwest of North America, are referred to as "false cedars". Plants called "cedar" include: Family Pinaceae *''Cedrus'', common English name cedar, a genus of coniferous trees in the plant family Pinaceae **Lebanon cedar, ''Cedrus libani'', a cedar native to Lebanon, western Syria and south-central Turkey **Atlas cedar, ''Cedrus atlantica'', a cedar native to the Atlas Mountains of Morocco and Algeria **Deodar cedar, ''Cedrus deodara'', a cedar native to the western Himalayas ** Cyprus cedar, ''Cedrus brevifolia'', found in the island of Cyprus's Cedar Valley in the Troodos Mountains *Siberian pine (''Pinus sibirica'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
