basalt formulir nalika lahar tekan lumahing bumi near vulkanik. suhu lava iku antarane 1100 1250 ° c nalika nemu menyang permukaan.
ganisters sing kawangun dening karusakan saka mineral gampang weathered utamané Feldspar, ing cakrawala lumahing lemah dening pangolahan lemah pambentuk.
olivine, plagioclase, pyroxene
kalsit, lempung, mineral lempung, Feldspar, micas, quartz
aluminium oxide, cao, wesi (iii) oxide, feo, kalium oxide, MgO, keda, sodium oxide, fosfor pentoxide, silikon dioksida, titanium dioxide
aluminium oxide, cao, wesi (iii) oxide, kalium oxide, MgO, sodium oxide, silikon dioksida