Section 3 Igneous Rock Features

Rocks.htm

Batholith Large, intrusive igneous rock Often granite or felsic composition

Sill Intrusive igneous rock forced between other layers Parallel to pre- existing layers Edinburg--Salisbury Crags

Dike Intrusive igneous rock forced between other rock Cuts across other rocks

Laccolith Intrusion between layers of sedimentary rock Often mound shaped at top

Volcanic Neck/Plug Magma that cooled in conduit of volcano Exposed by erosion of volcano Rhumsiki Peak, Cameroon

Problem Applying Math p 346 Classifying Igneous rocks 3 types of igneous rock based on silica content: –Granitic: More than 66% –Intermediate (Andesitic): 52%-66% –Basaltic: 45%-52%

A 900 kg block of igneous rock contains 630 kg of silica. What is its classification? What we know: –Total rock: 900 kg Silica: 630 kg Equation: –Percent = (Mass silica / Mass total) x 100 Put numbers in: –Percent = (630 kg/900 kg) x 100 Solve: –70% so it is _____________________