A geologist working in an area finds gravels with gentle dips of about 5 degrees.She finds a large outcrop where these gravels are overlain by tephra with prominent layers that dip 35-40 degrees.What is the history of this area?

Question

Quizplus · Accepted Answer

The gentle dips of about 5 degrees in the gravels suggest a deposition in a relatively calm environment, such as a river or a lake. The prominent layers of tephra with dips of 35-40 degrees suggest a more violent volcanic activity. This indicates that after the deposit of the gravels, a volcanic eruption occurred in the area, which produced the tephra layers with a higher angle of dip. The presence of cinders in the tephra suggests that it was produced by a cinder cone, which is a small, steep-sided volcano that erupts mostly cinders and ash. Therefore, option D is the most likely history of this area.

A Geologist Working in an Area Finds Gravels with Gentle