Notes on the origin of Colluma Crater, Bolivia

Journal of Research of the U.S. Geological Survey
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Abstract

Colluma Crater, on the semiarid Altiplano (high plain) of western Bolivia, is an oval structure having overall dimensions of 6.7 km by 6.0 km. The structure has two almost concentric cuestaform rims (the inner rim is 3.6 km by 3.1 km) composed of poorly consolidated clastic sediments that dip outward. The center of the crater is about 80 m below the maximum height of the rims and about at the altitude of the surrounding plain. Because of the double rim, the centripetal drainage, and the absence of volcanic rocks, this structure is considered a collapsed dome. We believe it was probably formed by the doming of lower Quaternary (?) sediments by a subjacent igneous intrusion, partial retreat of the magma, collapse of the central part of the dome, erosional etching of the two rims, and partial filling of the center by detritus from the walls. Evidence for origin by impact (nickel-iron materials, shock structures, ejecta, and so forth) is lacking or was unrecognized, but this mode of origin is not rejected at this time. Geophysical surveys are recommended to determine whether the structure continues in depth and if an igneous, plug is below the crater.

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Publication type Article
Publication Subtype Journal Article
Title Notes on the origin of Colluma Crater, Bolivia
Series title Journal of Research of the U.S. Geological Survey
Volume 3
Issue 1
Year Published 1975
Language English
Publisher U.S. Geological Survey
Description 8 p.
First page 31
Last page 38
Country Bolivia
Other Geospatial Colluma Crater
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