Recent volcanic history of Irazú volcano, Costa Rica: Alternation and mixing of two magma batches, and pervasive mixing
Published:January 01, 2006
Guillermo E. Alvarado, Michael J. Carr, Brent D. Turrin, Carl C. Swisher, III, Hans-Ulrich Schmincke, Kenneth W. Hudnut, 2006. "Recent volcanic history of Irazú volcano, Costa Rica: Alternation and mixing of two magma batches, and pervasive mixing", Volcanic Hazards in Central America, William I. Rose, Gregg J.S. Bluth, Michael J. Carr, John W. Ewert, Lina C. Patino, James W. Vallance
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40Ar/39Ar dates, field observations, and geochemical data are reported for Irazú volcano, Costa Rica. Volcanism dates back to at least 854 ka, but has been episodic with lava shield construction peaks at ca. 570 ka and 136–0 ka. The recent volcanic record on Irazú volcano comprises lava flows and a variety of Strombolian and phreatomagmatic deposits, with a long-term trend toward more hydrovolcanic deposits. Banded scorias and hybridized rocks reflect ubiquitous magma mixing and commingling. Two distinct magma batches have been identified. One magma type or batch, Haya, includes basalt with higher high field strength (HFS) and...