Mush remobilisation and mafic recharge: A study of the crystal cargo of the 2013–17 eruption at Volcán de Colima, Mexico

Volcán de Colima is a highly active stratovolcano at the western end of Trans-Mexican Volcanic Belt. Present-day activity consists lava dome growth and destruction cycles, flows, small explosions, larger explosive Vulcanian eruptions. It has been postulated that an increased frequency more mafic eruptions signals run-up to c. 100-year eruptive ‘cycles’, terminating with Plinian eruption such as those in 1818 1913. therefore important understand role played by recharge during interplinian activity. We present new petrological geochemical data for ash from 2013–17 phase eruption. The uniform paragenesis homogeneity bulk rocks indicate efficient long-term homogenisation magmas within plumbing system, similar previous 1998–2005 products. Mineral chemistry however preserves complex patterns magma mixing. Chemical textural information support interpretation two magmatic end-members – evolved end-member, saturated respect Fe--Ti oxides apatite crystallising low-An plagioclase pyroxenes Mg# 69–75 range; primitive, high-An 77–88 range. Pyroxene textures zoning suggest mixing melts remobilisation crystal mush. Two-pyroxene geothermometry constrains temperatures 980–1000 °C 1020–1080 end-member. Pressure estimates crystallisation 4–6 kbar, or 12–18 km depth. interpret this reflect periodic injections remobilised crystals into reservoirs mushy storage system mid-crust, agreement geophysical suggesting semi-molten, partially crystallised body An increase reverse zoned crystals, indicative injection, mid-2015 onwards suggests these were injected following large July 2015. Our findings intense 2015 may be linked input shallow indicating key process governing timing style Colima.