PGS: Lyle Mars on ASTER-mapping

Title: Hydrothermal alteration mapped using ASTER data, and how the hydrothermal alteration maps are applied to define potential economic deposit targets and to assess volcano debris flow hazards.

Speaker: John Carlyle Mars (Nickname Lyle) was born and raised in Mobile, Alabama and received his B.S. and M.S. degrees from the University of Alabama and a Ph.D. from the University of Kentucky. Lyle has worked for the last 16 years at the U.S. Geological Survey in the Eastern Mineral and Environmental Resources Science Center in Reston, Virginia. Lyle’s primary focus is the spectroscopic study and mapping of rocks and minerals associated with economic mineral deposits using multispectral and hyperspectral imaging instruments.


Abstract: Hydrothermally altered rocks contain clays and hydrous silica that exhibited diagnostic Al-OH and O-H spectral absorption features in the short wave infrared region (SWIR). Hydrothermally altered rocks are typically associated with economic deposits of copper, gold, silver, and molybdenum. In addition, hydrothermal alteration weakens volcanic slopes on volcanoes and increases the potential for debris flows and avalanches. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and Interactive Data Language (IDL) logical operator algorithms have been used to map hydrothermal alteration on volcanic edifices and to regionally map volcanic and magmatic arcs in order to identify targets of potential economic deposits in Iran, Pakistan, Afghanistan, Kazakhstan and the central and southern parts of the U.S. Basin and Range. Mineral map units of hydrothermal alteration features include hydrothermal silica, calcite-dolomite and epidote-chlorite (propylitic), alunite-pyrophyllite-kaolinite (argilllic), sericite-muscovite (phyllic) and jarosite. This talk will show how hydrothermal alteration is mapped using ASTER data, and how the hydrothermal alteration maps are applied to define potential economic deposit targets and to assess volcano debris flow hazards.

Meeting Room and Dining Arrangements: We now meet in the glassed-in room at the back of the main dining room—The Fife and Drum. We order individually from the Club menu, which has a nice variety of dinner offerings. We pay a single bill (I pay it with my Officers Club credit card), so we collect at least $25 from each diner with the agreement, that if one orders more than $20 in food and drink, he adds the amount over $20 to his contribution. The $5 overcharge goes to the Room Fee, Tax, Gratuity, and the Speaker’s Dinner. We collect on the Honor System. We did this throughout the last year, and it worked well. This room change and use of the menu have greatly reduced the loss that we have incurred in the past for having fewer than 20 people dining, and the change has preserved the viability of using the Officers Club for our meetings.

Reception at 6:00. Order Dinner at 7:00. Talk at 8:30 PM. Please note that the meal orders will be taken at 7:00. Allow 15 minutes for security entering Ft. Myer as all civilian vehicles are searched. To ensure access to and from Fort Myer use the Hatfield Gate, open 24 hours a day ( Reservations are not necessary, however, we need a head count, so, if you wish to attend dinner ($25), please inform Bob Fraser at 540-888-3001540-888-3001 or via E-mail at If you wish, please feel free to attend the talk without dinner. Non-members and guests are welcome. Visit the PGS web site at for new meeting announcements, etc. Please send changes of address or email to


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