Answer the questions below about igneous activity
which refer to the paper model. You may find that it helps to cut out and
fold the model into shape (but without gluing it) before you answer
Complete the missing igneous structures on the E, W and N sides of the
model by drawing them on the model. Label:
(a) a batholith - (huge structure, getting bigger with depth)
(b) a sill - (a sheet of rock parallel to the layers)
(c) a dyke (a sheet of rock cutting across the layers)
(d) a sheet lava flow (a sheet of lava on the surface)
(e) a volcano feeder pipe
Q 2. Make the
model by cutting it out and gluing the flaps.
Which of the structures would you expect to have:
(a) the igneous rock with the largest crystals (coarsest) – explain your
(b) the rock with the smallest crystals (finest) – explain your answer;
(c) rock with medium-sized crystals;
(d) ash layers between lava layers?
Which structure might be made of:
(a) gabbro (coarse-grained);
(b) dolerite (medium-grained);
(c) basalt (fine-grained)?
These rocks are chemically the same, but have different crystal sizes.