Katie Stack is Deputy Project Scientist for the NASA Perseverance rover that landed in Jezero crater on Mars in February 2021.  A geologist by training and an expert on the Martian sedimentary rock record, she has been mapping the geology of Mars since the 2000s.  She leads a large team of scientists that will combine orbiter and rover image data to investigate processes that took place on the the ancient surface of Mars. She describes what we are learning with the powerful instruments aboard Perseverance as it traverses an ancient Martian river delta deposit. For podcast illustrations, and to learn more about Geology Bites, go to geologybites.com.