Compilers: Glen T. Penfield, William I. Rose, and Sid P. Halsor
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One black and white sheet, 25" x 30". From text: The map depicts complex andesitic flows on composite volcanoes. The volcanoes San Pedro and Toliman are located entirely inside the Atitlan III caldera (Newhall, 1980) while Atitlan Volcano straddles the southern marginal fault of the caldera (Williams, 1960). The cones are probably younger than 85,000 yr B.P., the date of the last caldera-forming eruption (Drexler et al., 1980). The topographically distinguishable flows on the Toliman cone contrast with the uniform slopes developed on the undivided pyroclastic cover of the Atitlan cone. The San Pedro center is similar to Toliman, but has a more dissected and thickly vegetated surface. Petrologic study of summit lavas of Atitlan Volcano were made by Woodruff et al. (1979). A suite of samples was collected from all three volcanoes and analyzed for major and trace element chemistry by Penfield (1975). Isotopic data on the rocks of these volcanoes were used in an interpretive paper by Grant et al. (1984).
Published: 4/01/1986
Pages: 2 plus 1 sheet
Product Category: Maps and Charts