A geologist is working in an area of old volcanic rocks exposed by erosion.He finds a large rock outcrop that contains flat lying gravels in the base of the outcrop.These gravels are overlain by basalt that forms a series of layers representing flows.The uppermost basalt lava flows have a dip of about 10 degrees to the west.What does this outcrop record?

Question

Quizplus · Accepted Answer

The flat-lying gravels suggest deposition in a relatively stable environment, such as a river valley. The overlying basalt flows indicate volcanic activity after the gravels were deposited. The dip of the uppermost basalt layers suggests the formation of a shield volcano, which typically has gentle slopes.

A Geologist Is Working in an Area of Old Volcanic