The Vichada Structure is a probable impact structure

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 along the Vichada River

Vichada River

The Vichada River is a blackwater river in the country of Colombia, South America. It flows into the Orinoco River.The westward course of the Vichada is offset by an impact structure, called the Vichada Structure. The structure is most likely the largest impact structure in South America....

 in Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

 (Vichada Department

Vichada Department

Vichada is a department of the Republic of Colombia in South America. Vichada is located in the eastern plains of Colombia, in the Orinoquia region within the Orinoco river basin bordering the Bolivarian Republic of Venezuela to the north and east...

), South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. It is most likely the largest impact structure in South America.

The structure was discovered in 2004 by Max Rocca, a geologist

Geologist

A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...

 in Buenos Aires, by examining Landsat imagery. He is supported by a grant from the Planetary Society

Planetary Society

The Planetary Society is a large, publicly supported, non-government and non-profit organization that has many research projects related to astronomy...

. 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

Gravimetry

Gravimetry is the measurement of the strength of a gravitational field. Gravimetry may be used when either the magnitude of gravitational field or the properties of matter responsible for its creation are of interest...

 over the 50 km wide structure and discovered a positive free-air anomaly at the center of the structure, supporting its interpretation as an impact structure.