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U.S. Geological Survey Open File Report 2005-1038
Published 2005 - Online Only
Version 1.0 (En español)


Prepared in cooperation with the Escuela Geología, Minas y Geofísica, Universidad Central de Venezuela
and the Fundación Venezolana de Investigaciones Sismológicas

Geologic Shaded Relief Map of Venezuela

By Paul C. Hackley,1 Franco Urbani,2 Alex W. Karlsen,1 and Christopher P. Garrity1

1U.S. Geological Survey, Reston, VA 20192.
2Escuela Geología, Minas y Geofísica, Universidad Central de Venezuela and Fundación Venezolana de Investigaciones Sismológicas, Caracas, Venezuela.

Thumbnail of geologic shaded relief map of Venezuela The geologic shaded relief map of Venezuela was created by direct digitization of geologic and hydrologic data north of the Orinoco River from a 1:500,000 scale paper map set. These data were integrated with a digital geologic map of the Venezuela Guayana Shield, also derived from 1:500,000 scale paper maps. Fault type information portrayed on the map, including unlabeled fault types, are as depicted in the original data sources. Geologic polygons were attributed for age, name, and lithologic type following the Léxico Estratigráfico de Venezuela. Significant revisions to the geology of the Cordillera de la Costa were incorporated based on new, detailed (1:25,000 scale) geologic mapping. Geologic polygons and fold and fault lines were draped over a shaded relief image produced by processing 90 m (3-arc second) radar interferometric data obtained by the space shuttle radar topography mission (SRTM). Values for null-data areas inherent in the SRTM data set were filled by interpolation based on surrounding data cells. The digital elevation model data was hill-shaded using an illumination direction of 315 degrees at an angle of 65 degrees above the horizon to produce the shaded relief image. The map projection used is equidistant conic, with latitudes 4 and 9 degrees north as standard parallels, and longitude 66 degrees west as the central meridian.

The data contained in this map compilation primarily was derived from 1:500,000 scale maps and arranged for presentation and use at the scale of 1:750,000. Users may zoom in to view greater detail at larger scale; however, the authors make no guarantee of the accuracy of the map representation at scales larger than 1:750,000.

Nonsystematic misregistration of some geologic contacts and faults with topographic lineaments in the Guayana portion of the map becomes apparent with the drape of the older geologic data over the newly-available SRTM dataset. The geologic data of the Guayana area shown in this map was based on older imagery sources which contained registration and splice errors. Correction of nonsystematic misregistration errors is planned for future versions of the geologic map, and map users are encouraged to contact the authors to report inaccuracies (phackley@usgs.gov; urbani@cantv.net).

Data Available in this Report

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Direct questions and comments to:
Paul C. Hackley
U.S. Geological Survey
Email to: phackley@usgs.gov
Phone (703)-648-6458

U.S. Department of the Interior, U.S. Geological Survey
URL: http:// pubs.usgs.gov /of/2005/1038/index.html
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Last modified: 21:11:01 Sat 12 Jan 2013
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