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The Vichada Structure is a probable impact structure along the
The Vichada Structure is a probable impact structure along the Vichada River
The Vichada River ( es, Río Vichada, ) is a blackwater river in the country of Colombia, South America. It flows into the Orinoco River.
The eastward course of the Vichada is offset by an impact structure
An impact structure is a generally ...
in Colombia (Vichada Department
Vichada Department ( es, Departamento del Vichada, link=no, ) is a department of the Republic of Colombia in South America. Vichada is located in the eastern plains of Colombia, in the Orinoquía Region within the Orinoco river basin borderin ...
), South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
. It is most likely the largest impact structure in South America.
The structure was discovered in 2004 by Max Rocca, a geologist
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althoug ...
in Buenos Aires, by examining Landsat
The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to La ...
imagery. He was supported by a grant from the Planetary Society
The Planetary Society is an American internationally-active non-governmental nonprofit organization. It is involved in research, public outreach, and political space advocacy for engineering projects related to astronomy, planetary science, a ...
. The structure consists of a central flat depression surrounded by two concentric rings of hills of approximately 30 and 50 km diameter. The Vichada River anomalously flows around the outer ring of hills. An international team of scientists collected aerial gravity data over the 50 km wide structure and discovered a positive free-air anomaly In geophysics, the free-air gravity anomaly, often simply called the free-air anomaly, is the measured gravity anomaly after a free-air correction is applied to account for the elevation at which a measurement is made. It does so by adjusting these ...
at the center of the structure, supporting its interpretation as an impact structure.Hernandez, O., et al., 2009, Geophysical evidence for an impact crater in Vichada, northwestern South America, and its economic potential, Earth Sci. Res. J., Vol. 13, No. 2 (December 2009): 97-107
See also
* List of impact craters in South America *List of possible impact structures on Earth
This is a list of possible impact structures on Earth. More than 130 geophysical features on the surface of the Earth have been proposed as candidate sites for impact events by appearing several times in the literature and/or being endorsed by the ...
References
{{Impact cratering on Earth Impact craters of Colombia