Ignesous Rock LAyergreenspun.com : LUSENET : Introductory Geology, Oswego State : One Thread
About the last group activity, if an igneous rock layer is between 2 sedimentary rock layers of same composition, does that mean the igneous rock must be an intrusuion?
-- Amanda Fields (firstname.lastname@example.org), April 03, 2001
I explained the reasoning behind figuring out the relative ages of sedimentary rocks and the intrusion in that exercise in a previous question. Please read it.
Recall that in Chapter 4 you learned that a "sill" is a type of igneous intrusion. The igneous rock on the exercise was labeled a "diabase sill."
-- Sharon Gabel (email@example.com), April 03, 2001.