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Okmok reported activity

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EVENT SPECIFIC INFORMATION

Event Name : Okmok 2100000 yBP

Start: 2100000 (± 200000 Years) Years BP K-Ar

Lava flow: BibCard
Eruption Type:Effusive
Eruption Product: basalt BibCard
Othermafic

Description: From Miller and others (1998): "Construction of the pre-caldera volcano began in late Tertiary or early Quaternary time. Two whole-rock K-Ar analyses of a sample of basaltic lava are 1.7+/-2 and 2.1+/-2 m.y. (Bingham and Stone, 1973). Basaltic flows and pyroclastics compose most of the older rocks (unit Qbm, fig. 67 [in original text]); flows are more voluminous than pyroclastic deposits (see Byers, 1959, plate 41)."

"Flows and pyroclastic beds dip radially from the caldera at less than 5 degrees in most sectors, except for local steepening and reversal of dips at former vents. Such radial dips suggest that the older complex was a central volcano with parasitic vents."

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Page modified: March 30, 2017 14:36
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