Question

The upper and lower margins of sills are relatively ______________

(a) Coarser grain size

(b) Medium grain size

(c) Finer grain size

(d) Can be of any size

I had been asked this question during an online interview.

This intriguing question originated from Forms of Igneous Rocks in division The Study of Rocks of Engineering Geology

Answer 1

Right answer is (c) Finer grain size

For explanation I would say: The upper and lower margins of sills commonly show a comparatively finer grain size than their interior portions.