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 Lexico Estratigrafico 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. [Summary provided by the USGS.]