TY - JOUR
T1 - Explosive mafic volcanoes on Mars and Earth
T2 - Deep magma sources and rapid rise rate
AU - Gregg, Tracy K P
AU - Williams, Stanley
N1 - Funding Information:
We thank Ronald Greeley, Dan Ball, and Sue Selkirk for photographic assistance. Discussions with David Crown inspired this work. This manuscript was greatly improved thanks to reviews by L. Wilson and an anonymous referee. NASA Grant NAGW 529 from the Planetary Geology and Geophysics Program supported this research.
PY - 1996/8
Y1 - 1996/8
N2 - Volcanism on Mars is dominated by mafic or ultramafic products. On Earth, mafic volcanics are typically emplaced through small-scale pyroclastic activity such as lava fountaining or Strombolian eruptions, resulting in lava flows. Tyrrhena and Hadriaca Paterae, large, central-vent volcanoes on Mars, however, appear to be primarily constructed of mafic pyroclastic deposits (probably pyroclastic flows), and magma-water (or ice) interactions were not necessarily the cause of these explosive eruptions. The volcanotectonic conditions which generated highly explosive basaltic eruptions on Mars may exist on Earth as well: Masaya Caldera Complex, Nicaragua, has produced large-volume, basaltic ignimbrite, Plinian ash-fall and surge deposits, without overt magma-water interactions. Basaltic magma apparently originated ∼100 km beneath Masaya, and ascended faster than ∼100 cm s-1 through an established conduit, allowing the magma and exsolved volatiles to reach the surface simultaneously. The combination of deep-sourced magma and rapid rise rate may have also generated ignimbrite-like basaltic pyroclastic deposits at Zavaritski Volcano, Russia, and Ambrym, Vanuatu. Examination of these terrestrial volcanoes may further our understanding of large-scale mafic pyroclastic activity on Mars.
AB - Volcanism on Mars is dominated by mafic or ultramafic products. On Earth, mafic volcanics are typically emplaced through small-scale pyroclastic activity such as lava fountaining or Strombolian eruptions, resulting in lava flows. Tyrrhena and Hadriaca Paterae, large, central-vent volcanoes on Mars, however, appear to be primarily constructed of mafic pyroclastic deposits (probably pyroclastic flows), and magma-water (or ice) interactions were not necessarily the cause of these explosive eruptions. The volcanotectonic conditions which generated highly explosive basaltic eruptions on Mars may exist on Earth as well: Masaya Caldera Complex, Nicaragua, has produced large-volume, basaltic ignimbrite, Plinian ash-fall and surge deposits, without overt magma-water interactions. Basaltic magma apparently originated ∼100 km beneath Masaya, and ascended faster than ∼100 cm s-1 through an established conduit, allowing the magma and exsolved volatiles to reach the surface simultaneously. The combination of deep-sourced magma and rapid rise rate may have also generated ignimbrite-like basaltic pyroclastic deposits at Zavaritski Volcano, Russia, and Ambrym, Vanuatu. Examination of these terrestrial volcanoes may further our understanding of large-scale mafic pyroclastic activity on Mars.
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U2 - 10.1006/icar.1996.0132
DO - 10.1006/icar.1996.0132
M3 - Article
AN - SCOPUS:0030211014
SN - 0019-1035
VL - 122
SP - 397
EP - 405
JO - Icarus
JF - Icarus
IS - 2
ER -