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Hueyatlaco
Hueyatlaco is an archeological site in the Valsequillo Basin near the city of Puebla, Mexico. After excavations in the 1960s, the site became notorious due to geochronologists' analyses that indicated human habitation at Hueyatlaco was dated to ca. 250,000 years before the present. These controversial findings are orders of magnitude older than the scientific consensus for habitation of the New World (which generally traces widespread human migration to the New World to 13,000 to 16,000 ybp). The findings at Hueyatlaco are the subject of continued debate by the scientific community, and have seen only occasional discussion in the literature.Gonzalez, Silvia; Huddart, David; and Bennett Matthew. (2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valsequillo Dam )
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Valsequillo may refer to the following places: * Valsequillo de Gran Canaria, a municipality on the island of Gran Canaria in the province of Las Palmas in the Canary Islands. * Valsequillo, Córdoba, a municipality and a village in the province of Córdoba * A reservoir and area south of Puebla, Mexico, known for its Pleistocene remains (see Hueyatlaco Hueyatlaco is an archeological site in the Valsequillo Basin near the city of Puebla, Mexico. After excavations in the 1960s, the site became notorious due to geochronologists' analyses that indicated human habitation at Hueyatlaco was dated to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerutti Mastodon Site
The Cerutti Mastodon site is a paleontological and possible archeological site located in San Diego County, California. In 2017, researchers announced that broken mastodon bones at the site had been dated to around 130,700 years ago. The bones were found with cobblestones displaying use-wear and impact marks among the otherwise fine-grain sands. Researchers have proposed that these marks were caused by the intentional breakage of the broken bones by hominins using the cobblestones. If so, this suggestion would be older by far than the scientific consensus for habitation of the New World, which generally traces widespread human migration to the Americas to 13,000 to 16,000 years ago. Context The Cerutti Mastodon site (SDNHM locality 3767) is a paleontological site located in San Diego County, California, United States. A team of researchers from the San Diego Natural History Museum, led by Thomas Deméré, excavated the site from 1992 to 1993. The site is named after Richard C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xalnene Tuff Footprints
The Xalnene Tuff footprints are a geological academic controversy, concerning a 2005 discovery of 269 markings in a geological layer in the Valsequillo Basin, south of the city of Puebla, Mexico, which were originally interpreted to be human and animal footprints. The layer was variously dated to 40,000 years Before Present (BP) or 1.3million years BP, both dates significantly before the currently accepted date for the settlement of the Americas. A 2010 study argues that the marks were made by recent mining activities. Past theories The Clovis people were at one time considered to be the first inhabitants of the Americas, migrating into the area 13,100 years BP. However, tools, bone structures, genetics, and languages indicate that the early Americans were from many origins, and there have been some sites dated to 15–16,000 years BP. Methodology Carbon dating techniques were used. Implications of the discovery Implications of the find by González et al. are that other colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynthia Irwin-Williams
Cynthia Irwin-Williams (April 14, 1936 – June 15, 1990) was an archaeologist of the prehistoric American Southwest. She received a B.A. in Anthropology from Radcliffe College in 1957; the next year she received a M.A. in the same field. In 1963 she completed her educational career in Anthropology with a PhD. from Harvard University. Beginning her career in the 1950s, Irwin-Williams was considered a groundbreaker for women in archaeology, like her friend and supporter Hannah Marie Wormington.Cassells, E. Steve. (1997). ''The Archaeology of Colorado, Revised Edition.'' Boulder, Colorado: Johnson Books. pp. 298-299. . Archaeological career She worked with her brother, Henry Irwin, a fellow archaeologist, in Colorado from the mid-1950s to 1960. In 1966 Irwin-Williams and her brother published a book of her findings from the Magic Mountain site excavation performed for the Peabody Museum of Harvard University in 1959–1960. They also worked on the nearby and related LoDaisKa sit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral Weathering
Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), and so is distinct from erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity. Weathering processes are divided into ''physical'' and ''chemical weathering''. Physical weathering involves the breakdown of rocks and soils through the mechanical effects of heat, water, ice, or other agents. Chemical weathering involves the chemical reaction of water, atmospheric gases, and biologically produced chemicals with rocks and soils. Water is the principal agent behind both physical and chemical weathering, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Chemical weathering by biological action is also known as biological wea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Former Populated Places In Mexico
A former is an object, such as a template, gauge or cutting die, which is used to form something such as a boat's hull. Typically, a former gives shape to a structure that may have complex curvature. A former may become an integral part of the finished structure, as in an aircraft fuselage, or it may be removable, being using in the construction process and then discarded or re-used. Aircraft formers Formers are used in the construction of aircraft fuselage, of which a typical fuselage has a series from the nose to the empennage, typically perpendicular to the longitudinal axis of the aircraft. The primary purpose of formers is to establish the shape of the fuselage and reduce the column length of stringers to prevent instability. Formers are typically attached to longerons, which support the skin of the aircraft. The "former-and-longeron" technique (also called stations and stringers) was adopted from boat construction, and was typical of light aircraft built until the ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brunhes–Matuyama Reversal
The Brunhes–Matuyama reversal, named after Bernard Brunhes and Motonori Matuyama, was a geologic event, approximately 781,000 years ago, when the Earth's magnetic field last underwent reversal. Estimations vary as to the abruptness of the reversal. A 2004 paper estimated that it took over several thousand years; a 2010 paper estimated that it occurred more quickly, perhaps within a human lifetime; a 2019 paper estimated that the reversal lasted 22,000 years. The apparent duration at any particular location can vary by an order of magnitude, depending on geomagnetic latitude and local effects of non-dipole components of the Earth's field during the transition. The Brunhes–Matuyama reversal is a marker for the Global Boundary Stratotype Section and Point (GSSP) defining the base of the Chibanian Stage and Middle Pleistocene Subseries at the Chiba section, Japan, which was officially ratified in 2020 by the International Union of Geological Sciences. It is useful in dating ocea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleomagnetic
Paleomagnetism (or palaeomagnetismsee ), is the study of magnetic fields recorded in rocks, sediment, or archeological materials. Geophysicists who specialize in paleomagnetism are called ''paleomagnetists.'' Certain magnetic minerals in rock (geology), rocks can record the direction and intensity of Earth's magnetic field at the time they formed. This record provides information on the past behavior of the geomagnetic field and the past location of tectonic plates. The record of geomagnetic reversals preserved in Volcanic rock, volcanic and sedimentary rock sequences (magnetostratigraphy) provides a time-scale that is used as a geochronology, geochronologic tool. Evidence from paleomagnetism led to the revival of the continental drift hypothesis and its transformation into the modern theory of plate tectonics. Apparent polar wander paths provided the first clear geophysical evidence for continental drift, while marine magnetic anomaly, magnetic anomalies did the same for seafl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Society Of America
The Geological Society of America (GSA) is a nonprofit organization dedicated to the advancement of the geosciences. History The society was founded in Ithaca, New York, in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hitchcock, John R. Procter and Edward Orton and has been headquartered at 3300 Penrose Place, Boulder, Colorado, US, since 1967. GSA began with 100 members under its first president, James Hall. In 1889 Mary Emilie Holmes became its first female member. It grew slowly but steadily to 600 members until 1931, when a nearly $4 million endowment from 1930 president R. A. F. Penrose Jr. jumpstarted GSA's growth. As of December 2017, GSA had more than 25,000 members in over 100 countries. The society has six regional sections in North America, three interdisciplinary interest groups, and eighteen specialty divisions. Activities The stated mission of GSA is "to advance geoscience research and discovery, service to society, stewardship of Earth, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatom
A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of the Earth's biomass: they generate about 20 to 50 percent of the oxygen produced on the planet each year, take in over 6.7 billion metric tons of silicon each year from the waters in which they live, and constitute nearly half of the organic material found in the oceans. The shells of dead diatoms can reach as much as a half-mile (800 m) deep on the ocean floor, and the entire Amazon basin is fertilized annually by 27 million tons of diatom shell dust transported by transatlantic winds from the African Sahara, much of it from the Bodélé Depression, which was once made up of a system of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sangamonian
The Sangamonian Stage (or Sangamon interglacial) is the term used in North America to designate the last interglacial period. In its most common usage, it is used for the period of time between 75,000 and 125,000 BP.Willman, H.B., and J.C. Frye, 1970, ''Pleistocene Stratigraphy of Illinois.'' Bulletin no. 94, Illinois State Geological Survey, Champaign, Illinois. This period of time is equivalent to all of Marine Isotope Stage 5 and the combined Eemian period and early part of the Weichselian glaciation in Europe. Less commonly, the Sangamonian Stage is restricted to the period between 122,000 and 132,000 BP, which is equivalent to Marine Oxygen Isotope Substage 5e and the Eemian period of Europe. It preceded the Wisconsinan (Wisconsin) Stage and followed the Illinoian Stage in North America. Definition The Sangamonian Stage, originally the Sangamon interglacial stage, is defined on the basis of the Sangamon Soil, a paleosol, which is developed in contemporaneous colluvium and old ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biostratigraphy
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock Stratum, strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Biology'', 8th ed., Oxford University Press, 2019. The primary objective of biostratigraphy is ''correlation'', demonstrating that a particular Horizon (geology), horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the Sedimentary depositional environment, sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
