Rapid crystallization during recycling of basaltic andesite tephra: timescales determined by reheating experiments.

ABSTRACT: Microcrystalline inclusions within microlite-poor matrix are surprisingly common in low intensity eruptions around the world, yet their origin is poorly understood. Inclusions are commonly interpreted as evidence of crystallization along conduit margins. Alternatively, these clasts may be recycled from low level eruptions where they recrystallize by heating within the vent. We conducted a series of experiments heating basaltic andesite lapilli from temperatures below the glass transition (~690 °C) to above inferred eruption temperatures (>1150 °C) for durations of 2 to >60 minutes. At 690 °C < T < 800 °C, crystallization is evident after heating for ~20 minutes; at T > 800 °C, crystallization occurs in <5 minutes. At T ≥ 900 °C, all samples recrystallize extensively in 2-10 minutes, with p

SUBMITTER: Deardorff N 

PROVIDER: S-EPMC5389347 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature