Related Research Articles
In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leaves room for interpretation and is easier to apply to Precambrian times. To separate supercontinents from other groupings, a limit has been proposed in which a continent must include at least about 75% of the continental crust then in existence in order to qualify as a supercontinent.
The Snowball Earth is a geohistorical hypothesis that proposes during one or more of Earth's icehouse climates, the planet's surface became nearly entirely frozen with no liquid oceanic or surface water exposed to the atmosphere. The most academically mentioned period of such a global ice age is believed to have occurred some time before 650 mya during the Cryogenian period, which included at least two large glacial periods, the Sturtian and Marinoan glaciations.
Rodinia was a Mesoproterozoic and Neoproterozoic supercontinent that assembled 1.26–0.90 billion years ago (Ga) and broke up 750–633 million years ago (Ma). Valentine & Moores 1970 were probably the first to recognise a Precambrian supercontinent, which they named "Pangaea I." It was renamed "Rodinia" by McMenamin & McMenamin 1990, who also were the first to produce a plate reconstruction and propose a temporal framework for the supercontinent.
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is provided by tools such as paleomagnetism and stable isotope ratios. By combining multiple geochronological indicators the precision of the recovered age can be improved.
Paleomagnetism is the study of prehistoric Earth's magnetic fields recorded in rocks, sediment, or archeological materials. Geophysicists who specialize in paleomagnetism are called paleomagnetists.
The geology of the Himalayas is a record of the most dramatic and visible creations of the immense mountain range formed by plate tectonic forces and sculpted by weathering and erosion. The Himalayas, which stretch over 2400 km between the Namcha Barwa syntaxis at the eastern end of the mountain range and the Nanga Parbat syntaxis at the western end, are the result of an ongoing orogeny — the collision of the continental crust of two tectonic plates, namely, the Indian Plate thrusting into the Eurasian Plate. The Himalaya-Tibet region supplies fresh water for more than one-fifth of the world population, and accounts for a quarter of the global sedimentary budget. Topographically, the belt has many superlatives: the highest rate of uplift, the highest relief, among the highest erosion rates at 2–12 mm/yr, the source of some of the greatest rivers and the highest concentration of glaciers outside of the polar regions. This last feature earned the Himalaya its name, originating from the Sanskrit for "the abode of the snow".
Allan Verne Cox was an American geophysicist. His work on dating geomagnetic reversals, with Richard Doell and Brent Dalrymple, made a major contribution to the theory of plate tectonics. Allan Cox won numerous awards, including the prestigious Vetlesen Prize, and was the president of the American Geophysical Union. He was the author of over a hundred scientific papers, and the author or editor of two books on plate tectonics. On January 27, 1987, Cox died in an apparent suicide.
A geomagnetic reversal is a change in a planet's dipole magnetic field such that the positions of magnetic north and magnetic south are interchanged. The Earth's magnetic field has alternated between periods of normal polarity, in which the predominant direction of the field was the same as the present direction, and reverse polarity, in which it was the opposite. These periods are called chrons.
Frederick John Vine FRS was an English marine geologist and geophysicist. He made key contributions to the theory of plate tectonics, helping to show that the seafloor spreads from mid-ocean ridges with a symmetrical pattern of magnetic reversals in the basalt rocks on either side.
John Morris was an English geologist.
Edward A. "Ted" Irving, was a British-Canadian geologist. He was a scientist with the Geological Survey of Canada. His studies of paleomagnetism provided the first physical evidence of the theory of continental drift. His efforts contributed to our understanding of how mountain ranges, climate, and life have changed over the past millions of years.
(Stanley) Keith Runcorn was a British physicist whose paleomagnetic reconstruction of the relative motions of Europe and America revived the theory of continental drift and was a major contribution to plate tectonics.
Plate reconstruction is the process of reconstructing the positions of tectonic plates relative to each other or to other reference frames, such as the Earth's magnetic field or groups of hotspots, in the geological past. This helps determine the shape and make-up of ancient supercontinents and provides a basis for paleogeographic reconstructions.
David Evans is an American professor of geology and geophysics at Yale University. He works on quantitative reconstruction of supercontinents. He is involved in the Snowball Earth theory of Precambrian ice ages by demonstrating that the magnetic latitudes of ancient ice deposits were tropical. He is also the head of Berkeley College, one of Yale's fourteen residential colleges.
David Gubbins is a British former geophysicist concerned with the mechanism of the Earth's magnetic field and theoretical geophysics. He is Emeritus Professor of Earth Sciences at Leeds University.
Anne Grunow is a senior research scientist at Ohio State University in the Byrd Polar Research Center. She is also the current director of the Polar Rock Repository. Grunow is a geologist specializing in Antarctic tectonics, with her research using methods from geochronology and paleomagnetism.
Dennis V. Kent is an American geologist and geophysicist who is a Board of Governors Professor Emeritus at Rutgers University and an adjunct senior research scientist at Lamont–Doherty Earth Observatory of Columbia University. His research focuses on paleomagnetism, geomagnetism, rock magnetism, and their application to geologic problems, including geologic time scales, paleogeography, ancient climate, polar wander, and the long-term carbon cycle.
Richard G. Gordon is an American geophysicist, known for his research on global tectonics, including global plate motions and palaeomagnetism. He is noteworthy for leading two global plate motion projects: NUVEL and MORVEL. In the geosciences, NUVEL and MORVEL are standard models for global plate motions.
Alan Gilbert Smith was an English geologist, stratigrapher, and pioneer of plate tectonic reconstruction.
Kenneth Midworth Creer (1925–2020) was a British and Manx geophysicist who was the head of the geophysics department at the University of Edinburgh. He was the president of the European Geophysical Society from 1992 to 1994 and won the Gold Medal of the Royal Astronomical Society in 1996 among other accolades. Creer was an early pioneer of the theory of paleomagnetism, and was instrumental in producing the first paleomagnetic surveys and the first polar wandering curve.
References
- 1 2 3 4 Watson, J.V. (1985). "Proceedings, 30 May 1984. Annual General Meeting". Journal of the Geological Society, London. 142: 214–215.
- ↑ Briden, J.C. (1964). "Palaeolatitudes and palaeomagnetic studies, with special reference to pre-Carboniferous rocks in Australia".
- ↑ Briden, J. C. (October 11, 1966). "Variation of Intensity of the Palaeomagnetic Field Through Geological Time". Nature. 212 (5059): 246–247. Bibcode:1966Natur.212..246B. doi:10.1038/212246a0 – via www.nature.com.
- ↑ Briden, J. C.; Gass, I. G. (April 11, 1974). "Plate movement and continental magmatism". Nature. 248 (5450): 650–653. Bibcode:1974Natur.248..650B. doi:10.1038/248650a0 – via www.nature.com.
- ↑ "Announcements". Nature. 254 (5500): 543. April 11, 1975. Bibcode:1975Natur.254Q.543.. doi:10.1038/254543a0 – via www.nature.com.
- ↑ Allen, P. M. (2003). A geological survey in transition (PDF). British Geological Survey Occasional Publication. Vol. 1. ISBN 0-85272-426-8.
- ↑ "Supplementary catalogue of the papers and correspondence of Sir Richard Southwood (1931-2005)" (PDF). p. 30 – via National Cataloguing Unit for the Archives of Contemporary Scientists, University of Bath.
- ↑ Briden, J.C.; Downing, T.E. (2002). Managing the earth : the Linacre lectures 2001. Oxford University Press. pp. 1–188. ISBN 019925267X.
- ↑ Briden, Professor Jim (November 15, 2000). "What will the world be like in five years' time?". The Guardian.
- ↑ "Professors Emeritus" (PDF). Oxford University Gazette. 2018.
| International | |
|---|---|
| National | |
| Academics | |
| Other | |
