Jack Holt

Wednesday, April 25, 2:30-3:30 p.m., The Arizona Senior Academy Building.

Dr. John W. “Jack” Holt, University of Arizona

Since NASA’s Viking Orbiters reached Mars in the 1970s, scientists have worked to understand why a waterless and low-atmosphere planet would have substantial rocky debris around the base of mountains and other tall features. The mystery was finally solved when the Mars Reconnaissance Orbiter established that these deposits were actually glaciers disguised by a thin layer of rock and dust.

These glaciers have analogs here on Earth in the form of hidden glaciers. Such glaciers on Earth move far more slowly than exposed glaciers; because of the extreme cold of Mars, movement of its glaciers is almost imperceptible. As on Earth, glaciers on Mars could also hold the key to past climate and organic history.

Dr. Holt will explore how geophysical studies on both Earth and Mars will help unlock the inner workings and history of these enigmatic geographical features. Ice content and structure are being mapped from the surface and the air. Given glaciers’ capability to store significant fresh water (about 75% of the Earth’s total), a better understanding of Martian glaciers could remove a major obstacle to human exploration there.

Dr. Holt is Professor in two Departments—Planetary Sciences and Geosciences—at the University of Arizona. He has held many positions in his field, notably multiple professorial roles at the University of Texas Institute for Geophysics in Austin; and he has conducted research at the Jet Propulsion Laboratory in Pasadena. He earned his Bachelor’s degree at Rice University and both an M.S. and Ph.D. in Geology at California Institute of Technology. He has received numerous awards and honors and has published widely in his field.

Written by Roxy Mitchem-Horn, Academy Village volunteer

Apr. 25: “The Slow, the Fast, and the Buried: Probing Glaciers on Earth and Mars”