Why is it unlikey that fossils would be found in ingenous rocks?

Answer 1

Igneous rocks began as hot, fluid material - from lava erupted at the Earth's surface forming extrusive rocks, from magma (unerupted lava) at shallow depths forming intrusive rocks, or from magma in deep bodies (plutons) forming plutonic rocks. But whatever the form the nature of their formation, the heat at formation, any organic material would immediately burn up rather than become fossilised. The absence of fossils is a simple and obvious indicator that any given contextual rock or strata is igneous.