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Yavapai Supergroup
The Yavapai Supergroup is a Paleoproterozoic supergroup of metavolcanic and metasedimentary rock strata, partially exposed in Arizona, US. The corresponding chronostratigraphic unit is the Yavapai Series, which locally defines an interval of geologic time. The Yavapai Supergroup gives its name to the Yavapai orogeny, a major mountain-building event that took place in the U.S. Southwest in the Paleoproterozoic. Geology The Yavapai Supergroup is extensively exposed in Yavapai County, Arizona, from which it takes its name. Exposures are found from the Jerome — Prescott area southwest to Mingus Mountain and in other parts of the Arizona transition zone. The supergroup contains a variety of lithologies (rock types). The beds of the supergroup were laid down between 1820 and 1770 million years ago. History of investigation The beds belonging to the unit were first named as the "Arizonian" by W.P. Blake in 1899. They were subsequently formally named as the Yavapai Schist by Thomas Jag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supergroup (stratigraphy)
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it. Units must be ''mappable'' and ''distinct'' from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%". Lithostratigraphic units Sequences of sedimentary and volcanic rocks are subdivided the basis of their shared or associated lithology. Formally identified lithostratigraphic units are structured in a hierarchy of lithostratigraphic rank, higher rank units generally comprising two or more units of lower rank. Going from smaller to larger in rank, the main lithostratigraphic ranks are Bed, Member, Formation, Group and Supergroup. Formal names of lithostratigraphic units are assigned by geological surveys. Units of formation or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jerome, Arizona
Jerome is a town in the Black Hills of Yavapai County in the U.S. state of Arizona. Founded in the late 19th century on Cleopatra Hill overlooking the Verde Valley, Jerome is located more than above sea level. It is about north of Phoenix along State Route 89A between Sedona and Prescott. Supported in its heyday by rich copper mines, it was home to more than 10,000 people in the 1920s. As of the 2010 census, its population was 444. It is now known for its tourist attractions, such as its "ghost town" status and local wineries. The town owes its existence mainly to two ore bodies that formed about 1.75billion years ago along a ring fault in the caldera of an undersea volcano. Tectonic plate movements, plate collisions, uplift, deposition, erosion, and other geologic processes eventually exposed the tip of one of the ore bodies and pushed the other close to the surface, both near Jerome. In the late 19th century, the United Verde Mine, developed by William A. Clark, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Supergroups Of The United States
Geology () is a branch of natural science concerned with Earth and other Astronomical object, astronomical objects, the features or rock (geology), rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth science, Earth sciences, including hydrology, and so is treated as one major aspect of integrated Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the Relative dating, relative and Geochronology, absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mazatzal Orogeny
The Mazatzal orogeny was an orogenic event in what is now the Southwestern United States from 1650 to 1600 Mya in the Statherian Period of the Paleoproterozoic. Preserved in the rocks of New Mexico and Arizona, it is interpreted as the collision of the 1700-1600 Mya age Mazatzal island arc terrane with the proto-North American continent. This was the second in a series of orogenies within a long-lived convergent boundary along southern Laurentia that ended with the ca. 1200–1000 Mya Grenville orogeny during the final assembly of the supercontinent Rodinia, which ended an 800-million-year episode of convergent boundary tectonism. Description Age and isotope data show that southern North America is composed of a series of northeast-trending provinces representing island arc terranes accreted onto the 1800 Mya core of Laurentia. These are the Yavapai province (1800–1700 Mya), the Mazatzal province (1700–1650 Mya), the Granite-Rhyolite province (1500–1300 Mya), and the L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alder Group
The Alder Group is a group of geologic formations exposed in the Mazatzal Mountains of central Arizona, US. It dates to the Statherian Period of the Paleoproterozoic and records mountain-building events associated with the assembly of North America. Description The formation consists of about of metavolcanic and metasedimentary rock exposed in the Mazatzal Mountains. The formation is underlain by the East Verde River Formation and overlain by the Red Rock Group. Together with the younger Mazatzal Group, these groups form the Tonto Basin Supergroup. The formation is mostly volcanic and volcaniclastic sedimentary rock, but with some sedimentary beds formed by weathering of continental rock (''terrigenous'' beds). All have experienced metamorphism. The Alder Group is interpreted as basin fill of an intra-arc basin that formed along what was then the southern coast of Laurentia Laurentia or the North American Craton is a large continental craton that forms the ancient ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Rock Rhyolite
Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondary color (made from magenta and yellow) in the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy. Red pigment made from ochre was one of the first colors used in prehistoric art. The Ancient Egyptians and Mayans colored their faces red in ceremonies; Roman generals had their bodies colored red to celebrate victories. It was also an important color in China, where it was used to color early pottery and later the gates and walls of palaces. In the Renaissance, the brilliant red costumes for the nobility and wealthy were dyed with kermes and cochineal. The 19th century ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distinguished from its neighbor by its lithology, but all were deposited in the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphism
Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including regional, contact, hydrothermal, shock, and dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasing temperature and pressure characterize ''retrograde metamorphism''. Metamorphic petrology is the study of metamorphism. Metamorphic petrol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Palache
Charles Palache (July 18, 1869 – December 5, 1954) was an American mineralogist and crystallographer. In his time, he was one of the most important mineralogists in the United States. Background Charles Palache came from the Pallache family of Sephardic Jews. His grandfather, John Palache, had a plantation in Jamaica. His father, James Palache, was born in New York and moved to San Francisco as a merchant. His mother was Helen Whitney. His memorial at the National Academy of Sciences reports: For political reasons he ohn Palacheabandoned that home in 1834, and put his wife and three daughters on a ship sailing for New York, but he died before he could follow them on the next boat. Three months later Charles Palache's father, James, was born in New York City. At the age of fifteen, James acted as cabin boy on a schooner rounding Cape Horn and in 1849 landed in San Francisco, his home henceforth. Palache attended Berkeley High School. He became interested early on in natu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Jaggar
Thomas Augustus Jaggar Jr. (January 24, 1871 – January 17, 1953) was an American volcanologist. He founded the Hawaiian Volcano Observatory and directed it from 1912 to 1940. The son of Thomas Augustus Jaggar, Jaggar Jr. graduated with a Ph.D. in geology from Harvard University in 1897. In 1902, he was one of the scientists that the United States sent to investigate the volcanic disasters at La Soufrière volcano, St Vincent, and Mont Pelée, Martinique, which he credited with inspiring him to make a life's work out of geology. He became head of the department of geology at Massachusetts Institute of Technology in 1906. Jaggar traveled to Hawaii in 1909, where he began fundraising to establish the Hawaiian Volcano Observatory (HVO). Jaggar became the first director of HVO in 1912, and remained at HVO until 1940, when he retired and became a research associate in geophysics at the University of Hawaii. Jaggar married twice in his life, and had two children. He died in 1953 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithologies
The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lithology may refer to either a detailed description of these characteristics, or a summary of the gross physical character of a rock. Examples of lithologies in the second sense include sandstone, slate, basalt, or limestone. Lithology is the basis of subdividing rock sequences into individual lithostratigraphic units for the purposes of mapping and correlation between areas. In certain applications, such as site investigations, lithology is described using a standard terminology such as in the European geotechnical standard Eurocode 7. Rock type The naming of a lithology is based on the rock type. The three major rock types are igneous, sedimentary, and metamorphic. Igneous rocks are formed directly from magma, which is a mixture of mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arizona Transition Zone
The Arizona transition zone is a diagonal northwest-by-southeast region across central Arizona. The region is a transition from the higher-elevation Colorado Plateau in Northeast Arizona and the Basin and Range region of lower-elevation deserts in the southwest and south. Northwest Arizona transitions to the lower elevation Mojave Desert of southern California, Nevada and Utah, with an indicator species of Joshua trees and other species, and southwestwards regions of the Sonoran Desert, along the Lower Colorado River Valley; in Arizona's south, all of central and eastern desert Sonoran Desert regions merge southwards into Sonora Mexico. The transition zone includes the Mogollon Rim and the White Mountains and extends into western New Mexico. In the Arizona ecoregion section, the Arizona transition zone is the major section of the EPA designated, Level III ecoregion, '' Arizona/New Mexico Mountains ecoregion''. The other two outlier subregions to the transition zone in Arizon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
