Event Name : Wrangell Mount ZanettiThis is a questionable event.
|Start: 50000 (± 80000 Years) || Years BP K-Ar || |
|Lava flow: ||
|Eruption Product: || andesite ||
From Miller and others (1998): "Mt. Zanetti (3965 m) a large (350 m high) steep-sided, relatively undissected cinder-spatter cone occurs high on the northwest flank of the shield and may be the source of some lava flows. Lavas on the southwest flank have flowed as much as 59 km from their source despite being phenocryst-rich andesite, a mobility attributed to a very high eruptions rate (Nye, 1983)."
Richter and others (1995) state: "On the basis of radiometric dating K-Ar dating, the lava flows most recently erupted from Mount Wrangell may be 50,000 to 100,000 years old...the one of Mount Zanetti and a few flows on the south flank of Mount Wrangell are probably the youngest products of the volcano. Mount Zanetti probably erupted during the waning stage of the latest major glaciation, possibly less than 25,000 years ago, and a large, young andesite flow that originated in the summit area and traveled more than 40 m (64 km) south and west in the ancestral Copper River Basin may only be 50,000 years old."
From Richter and others (1990): "K-Ar ages of 0.05 and 0.06 Ma ([sample] no. 1) were determined on a large and extremely long andesite flow that debouched into the Copper River Basin probably in late Pleistocene time (Yehle and Nichols 1980). These determinations, however, have such large analytical uncertainties that meaningful ages cannot be assigned (JD Obradovich, personal communication 1979)."