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Geology and geochemistry of the Wanamu-Blue Mountains area, Waini SW, Guyana

Open-File Report 68-157

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Abstract

The Wanamu-Blue Mountains area is situated in the Northwest District of Guyana, about 110 miles northwest of Georgetown. The Blue Mountains are low, but rugged, hills that have developed on mafic metamorphic rocks that occur in an arcuate "mantle" around a granite batholith, the Aranka-Wanamu Granite. The area lies within the Precambrian Guiana Shield and is entirely covered with tropical rain forest. The geology of the area is complex and is made up of an assemblage of metamorphic rocks consisting of phyllites, quartzites, amphibolites, and epidiorites that are intruded by serpentinites. The serpentinites occur as thin, tabular, dike-like bodies that trend northwest across the area. The serpentinites contain abundant magnetite, but very little chromite or sulfide minerals. Lletasomatic reaction zones have developed around the serpentinite bodies at their contacts with country rock. These reaction zones consist of aureoles of actinolite schist, chloritic hornfels, and talcose zones in the phyllites.

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Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geology and geochemistry of the Wanamu-Blue Mountains area, Waini SW, Guyana
Series title:
Open-File Report
Series number:
68-157
Year Published:
1968
Language:
English
Publisher:
U.S. Geological Survey
Description:
Report: xiv, 178 p.; 7 Plates: 51.29 x 41.30 inches or smaller
Country:
Guyana
Other Geospatial:
Wanamu-Blue Mountains