Kodachrome Slides (IMAGE) University at Buffalo Caption University at Buffalo geology professor Greg A. Valentine holds up Kodachrome slides showing photographs of geologic formations associated with the eruption of the Silver Creek caldera supervolcano 18.8 million years ago. Valentine collected the data in the 1980s as a PhD student. Credit Douglas Levere Usage Restrictions This image may only be used with news reports discussing the research in the associated press release. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.