ite , ▁il men ite , ▁magnet ite ▁and ▁z ir con ▁can ▁also ▁be ▁found . ▁There ▁is ▁evidence ▁of ▁mag ma ▁mixing ▁and ▁m ing ling . ▁ ▁Ro cks ▁have ▁a ▁por phy rit ic ▁texture . ▁Bas alt ic ▁and es ites ▁typically ▁contain ▁less ▁than ▁ 1 0 % ▁cry st als ▁while ▁d ac ites ▁generally ▁have ▁more ▁than ▁ 2 0 % ▁cry st als . ▁The ▁Al con cha ▁group ▁la vas ▁of ▁the ▁first ▁one ▁million ▁years ▁are ▁cry stal - po or ▁and ▁lack ▁bi ot ite ; ▁later ▁la vas ▁contain ▁bi ot ite ▁and ▁more ▁cry st als . ▁Based ▁on ▁ge oth erm ometric ▁data , ▁the ▁highest ▁temper atures ▁occurred ▁during ▁phases ▁of ▁high ▁activity ▁and ▁lower ▁temper atures ▁are ▁associated ▁with ▁low ▁output ▁periods . ▁It ▁is ▁likely ▁that ▁cr ust al ▁feedback ▁and ▁increased ▁deep ▁cr ust al ▁infl ux ▁of ▁mant le - der ived ▁bas al ts ▁drive ▁increased ▁mag m atic ▁flux . ▁During ▁the ▁time ▁of ▁the ▁Pol an ▁er u ption ▁on ▁the ▁west ▁fl ank , ▁mag ma ▁output ▁was ▁spatial ly ▁seg reg ated ▁with ▁the ▁peri pher al ▁Mi ño ▁Vol cano ▁generating ▁and es ite ▁la vas ▁and ▁the ▁more ▁central ▁vol can os ▁generating ▁d ac ites . ▁ ▁Vari ous ▁parts ▁of ▁the ▁main ▁vol cano ▁have ▁been ▁subject ed ▁to ▁hydro ther mal ▁alter ation . ▁The ▁Az uf rera ▁stage ▁ed ifice ▁was ▁subject