Broken Top

sopka (bez známé erupce za posledních ~12 000 let), United States, North America Volcanic Regions

Kde

United States, North America Volcanic Regions

Typ (GVP)

Stratovolcano

Nadmořská výška

2 797 m

Poloha

44,080°, -121,700°

Broken Top is a complex dominantly basaltic andesite stratovolcano immediately SE of South Sister volcano. It is extensively eroded by glaciers, with the summit crater breached to the SE. Intermittent eruptions of andesite, dacite, and rhyolite have produced lava flows, pyroclastic flows, and airfall tephra. A late Pleistocene or early Holocene debris avalanche traveled 7 km N (Hildreth et al., 2012). Cayuse Crater on the upper SW flank is considered to be related to a possible magma reservoir underlying the South Sister area, and is assigned to South Sister rather than Broken Top (Fierstein et al., 2011). A radiocarbon age of 9,520 +/- 100 years before present (BP) from sediment beneath Cayuse Crater scoria is considered to be suspect because of lack of pretreatment and possible contamination by younger material. The scoria overlies glacial till considered to be 11,000-12,500 or as old as 14,000 years BP (Sherrod 1995, pers. comm.).

Text: Smithsonian Global Volcanism Program.

Údaje o sopce: Smithsonian Global Volcanism Program. Další sopky a průduchy.