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| International | |
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| National | |
| Formation | 1948 |
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| Type | Society |
| Headquarters | Tucson, Arizona |
Membership | 346 |
Official language | English |
President | Alison Jones (2013) [1] |
| Website | www.arizonageologicsoc.org |
The Arizona Geological Society (AGS) is a non-profit scientific organization founded in 1948 whose purpose is to promote and encourage interest in the science of geology and in the geology of the State of Arizona. [2] The Society holds monthly meetings, and sponsors field trips and symposia. Membership is open to professional geoscientists and those who are interested in Arizona geology. Membership categories include Voting Members, Student Members, Honorary Life Members, and 50-Year Members.
Honorary Life Members include: Spencer R. Titley (1996), John M. Guilbert (1998), Walter E. Heinrichs, Jr. (2008), Donald Hammer (April 2009), and Corolla Hoag (2010).
Institutional members includes the current Director of the Arizona Geological Survey in Tucson.
AGS Maps, Digests, and Guidebooks are published at irregular intervals.
The society is managed by a 15-member Executive Committee consisting of Officers and Advisory Councilors who serve calendar-year terms. The Officers include President, Vice President-Field Trips, Vice President-Programs, Vice President-Marketing, Secretary, Vice-Secretary, Treasurer, and Vice-Treasurer; their duties are specified in the Bylaws of the society. The Advisory Council consists of six members who serve staggered three-year terms; their duties are to promote interest in AGS activities and supervise special projects undertaken by the society. The seventh member of the Advisory Council is the immediate Past-President who serves as Chair of the Advisory Committee. The Executive Committee serves without remuneration.
There are three other committees nominated by the Executive Committee to perform specific duties. These include the Investment Committee, the J. Harold Courtright Scholarship Committee, and the Nominating Committee.
Arizona Geological Society has prepared two Arizona geologic highway maps, one of which is still in print. The 1998 highway map was prepared in collaboration with the Arizona Geological Survey.
AGS Digests are a serial geologic publication produced on an irregular basis usually as a compilation of papers presented at a scientific symposium. The first Digest was produced in 1952; the most recent was Digest 22 published in 2008. The Digests have International Standard Serial Number ISSN 0066-7412
Over the decades, AGS field trips have visited every part of Arizona's varied landscape and geology. The trips are intended for professional geologists, and led by geologists with the U.S. Geological Survey, Arizona Geological Survey and other governmental agencies, the three major Arizona universities, mine geology departments at the producing mines, and by graduate students presenting their research topics and thesis or dissertation progress. For the Spring or Fall field trips, a formal guidebook is prepared.
Historically AGS symposia have focused on the connections between the geology of ore deposits and structural geology with associated pre- and post-meeting field trips and a compendium of papers prepared after the meetings. They have traditionally been co-sponsored by the U.S. Geological Survey branch in Tucson, the University of Arizona, and/or other professional geological societies and organizations. A list of the past symposia include the:
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Orogeny is a mountain-building process that takes place at a convergent plate margin when plate motion compresses the margin. An orogenic belt or orogen develops as the compressed plate crumples and is uplifted to form one or more mountain ranges. This involves a series of geological processes collectively called orogenesis. These include both structural deformation of existing continental crust and the creation of new continental crust through volcanism. Magma rising in the orogen carries less dense material upwards while leaving more dense material behind, resulting in compositional differentiation of Earth's lithosphere. A synorogenic process or event is one that occurs during an orogeny.
The Entrada Sandstone is a formation in the San Rafael Group found in the U.S. states of Wyoming, Colorado, northwest New Mexico, northeast Arizona, and southeast Utah. Part of the Colorado Plateau, this formation was deposited during the Jurassic Period sometime between 180 and 140 million years ago in various environments, including tidal mudflats, beaches, and sand dunes. The Middle Jurassic San Rafael Group was dominantly deposited as ergs in a desert environment around the shallow Sundance Sea.
The Llano Uplift is a geologically ancient, low geologic dome that is about 90 miles (140 km) in diameter and located mostly in Llano, Mason, San Saba, Gillespie, and Blanco counties, Texas. It consists of an island-like exposure of Precambrian igneous and metamorphic rocks surrounded by outcrops of Paleozoic and Cretaceous sedimentary strata. At their widest, the exposed Precambrian rocks extend about 65 miles (105 km) westward from the valley of the Colorado River and beneath a broad, gentle topographic basin drained by the Llano River. The subdued topographic basin is underlain by Precambrian rocks and bordered by a discontinuous rim of flat-topped hills. These hills are the dissected edge of the Edwards Plateau, which consist of overlying Cretaceous sedimentary strata. Within this basin and along its margin are down-faulted blocks and erosional remnants of Paleozoic strata which form prominent hills.
Porphyry copper deposits are copper ore bodies that are formed from hydrothermal fluids that originate from a voluminous magma chamber several kilometers below the deposit itself. Predating or associated with those fluids are vertical dikes of porphyritic intrusive rocks from which this deposit type derives its name. In later stages, circulating meteoric fluids may interact with the magmatic fluids. Successive envelopes of hydrothermal alteration typically enclose a core of disseminated ore minerals in often stockwork-forming hairline fractures and veins. Because of their large volume, porphyry orebodies can be economic from copper concentrations as low as 0.15% copper and can have economic amounts of by-products such as molybdenum, silver, and gold. In some mines, those metals are the main product.
Waldemar Lindgren was a Swedish-American geologist and a founder of modern economic geology.
A polymetallic replacement deposit, also known as carbonate replacement deposit or high-temperature carbonate-hosted Ag-Pb-Zn deposit, is an orebody of metallic minerals formed by the replacement of sedimentary, usually carbonate rock, by metal-bearing solutions in the vicinity of igneous intrusions. When the ore forms a blanketlike body along the bedding plane of the rock, it is commonly called a manto ore deposit. Other ore geometries are chimneys and veins. Polymetallic replacements/mantos are often stratiform wall-rock replacement orebodies distal to porphyry copper deposits, or porphyry molybdenum deposits. The term manto is from the Spanish word for mantle, or cloak, although the geologic manto is more like a mantle roll than a sheetlike structure.
James (Jim) W.H. Monger is an emeritus scientist of the Geological Survey of Canada and a world leader in the application of plate tectonics to the study of mountain chain formation.
The Arizona Geological Survey (AZGS) was established by the Arizona Legislature to investigate and describe Arizona's geology and to educate and inform the public regarding its geologic setting. Each year since 1915, AZGS has released geologic maps, formal reports, and other geology-related publications. In Tucson, the Survey maintains a geological library comprising more than 15,000 volumes and approximately 100 linear feet of mine files that include newspaper clippings, maps, mine schematics and mine reports; it also maintains a small core repository of donated rock core. In addition, AZGS archives well cuttings of more than 1,000 oil and gas wells on behalf of the Arizona Oil and Gas Conservation Commission. The AZGS Phoenix branch maintains tens-of-thousands of mine maps and reports acquired in 2011 when the Arizona Department of Mines and Mineral Resources merged with AZGS. The Survey main office is located in the State Office complex in downtown Tucson).
Granite Mountain is a 7,628-foot (2,325 m) mountain located in Yavapai County, Arizona that covers roughly 12 square miles (31 km2). It was once known as Mount Gurley, for the first governor of the Arizona Territory, John A. Gurley. Its southwest face has a sheer granite cliff approximately 500 feet high that is one of the best locations for rock climbing in the state of Arizona. It is located in the Granite Mountain Wilderness, which is managed as a part of the Prescott National Forest. The mountain stands at the northern end of the Sierra Prietas, and borders Skull Valley on the west, on the northwest by the Santa Maria Mountains, and east by the Williamson Valley.
Helvetia is a ghost town in Pima County, Arizona, United States that was settled in 1891 and abandoned in the early 1920s. Helvetia is an ancient name for Switzerland.
Leon Theodore "Lee" Silver was an American geologist who was professor of geology at the California Institute of Technology (Caltech). He was an instructor to the Apollo 13, 15, 16, and 17 astronaut crews. Working with the National Aeronautics and Space Administration (NASA), he taught astronauts how to perform field geology, essentially creating lunar field geology as a new discipline. His training is credited with a significant improvement in the J-Mission Apollo flights' scientific returns. After the Apollo program, he became a member of the United States National Academy of Sciences in 1974. He retired in 1996 as the W. M. Keck Foundation Professor for Resource Geology, emeritus, at Caltech.
The Cypress Hills Formation is a stratigraphic unit of middle Eocene to early Miocene age in the Western Canada Sedimentary Basin. It is named for the Cypress Hills of southeastern Alberta and southwestern Saskatchewan and was first described from outcrops on the slopes of the Cypress Hills in 1930. It is known for preserving a wealth of vertebrate fossils.
The geology of Bolivia comprises a variety of different lithologies as well as tectonic and sedimentary environments. On a synoptic scale, geological units coincide with topographical units. The country is divided into a mountainous western area affected by the subduction processes in the Pacific and an eastern lowlands of stable platforms and shields. The Bolivian Andes is divided into three main ranges; these are from west to east: the Cordillera Occidental that makes up the border to Chile and host several active volcanoes and geothermal areas, Cordillera Central once extensively mined for silver and tin and the relatively low Cordillera Oriental that rather than being a range by its own is the eastern continuation of the Central Cordillera as a fold and thrust belt. Between the Occidental and Central Cordillera the approximately 3,750-meter-high Altiplano high plateau extends. This basin hosts several freshwater lakes, including Lake Titicaca as well as salt-covered dry lakes that bring testimony of past climate changes and lake cycles. The eastern lowlands and sub-Andean zone in Santa Cruz, Chuquisaca, and Tarija Departments was once an old Paleozoic sedimentary basin that hosts valuable hydrocarbon reserves. Further east close to the border with Brazil lies the Guaporé Shield, made up of stable Precambrian crystalline rock.
The Atacama Fault Zone (AFZ) is an extensive system of faults cutting across the Chilean Coastal Cordillera in Northern Chile between the Andean Mountain range and the Pacific Ocean. The fault system is North-South striking and runs for more than 1100 km North and up to 50 km in width through the Andean forearc region. The zone is a direct result of the ongoing subduction of the Eastward moving Nazca Plate beneath the South American Plate and is believed to have formed in the Early Jurassic during the beginnings of the Andean orogeny. The zone can be split into 3 regions: the North, Central and South.
Sharon Mosher is an American geologist. She did her undergraduate work at University of Illinois Urbana-Champaign. After earning an MSc from Brown University, she returned to the University of Illinois to get her PhD in Geology in 1978. Since 2001 she has held the William Stamps Farish Chair at University of Texas, and, since 2009 she has served as the dean of the Jackson School of Geosciences at Texas. In 2013 she became the president of the American Geosciences Institute.
The Lake Valley Limestone is a geologic formation widely exposed in southwestern New Mexico. It preserves fossils dating back to the lower to middle Mississippian.
The Blood Reserve Formation, also known as the Blood Reserve Sandstone, is a geologic formation of Late Cretaceous (Campanian) age in the Western Canada Sedimentary Basin. It is present in southwestern Alberta, Canada, and was named for Blood Indian Reserve No. 148 by L.S. Russell in 1932. It is an aquifer and a source of fresh groundwater.
Tobífera Formation is a volcano-sedimentary formation of Middle to Late Jurassic age. The formation is crops out in the Magallanes Region in southern Patagonia and Tierra del Fuego of Chile, the Santa Cruz Province of southern Argentina, and in the subsurface of the Malvinas Basin offshore Argentina and the Falkland Islands.
Zapata Formation is a sedimentary formation of Lower Cretaceous age in the Magallanes or Austral Basin of Argentina and Chile. Much of the formation is folded and faulted as consequence of the Andean orogeny. In outcrops of the Zapata Formation near Torres del Paine, the southernmost fossil of the ichthyosaur genus Platypterygius has been found.
Sarah-Jane Barnes is a British-Canadian geologist, who is a professor at the Université du Québec à Chicoutimi and director of LabMaTer.
