Write an inquisitive question about a specific text span in a given sentence such that the answer is not in the text.

Sentence: Geologist Erin Argyilan has in the last 10 months studied sediment , analyzed wind patterns and mapped terrain , but she hasn ' t solved the mystery of the holes that appear and vanish in the beige sands of Mount Baldy at Indiana Dunes National Lakeshore .<sep>Span: studied
How did Erin Argylian study this sediment?