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Holey Basalt, Robin! The pillow lavas of the Connecticut Valley

"Holey basalt" is a term for vesicular basalt, a type of volcanic rock that contains numerous small holes (vesicles) left by gas bubbles that were trapped as the lava cooled. These holes give the rock a porous and lightweight texture, and they can also be larger, forming lava tubes, or even filled with crystals. The unique structure, appearance, and uses of this unusual volcanic material will be highlighted.

This class will consist of a one-day excursion. Leaving from campus, we will drive to Greenfield (Massachusetts) Community College for a one-hour presentation. After stopping for lunch, we will visit readily accessible Greenfield sites, including columns and other lava formations reached on a 30-minute woodland walk. We will then drive up to Poet's Seat Tower, a 1912 sandstone observation tower offering a 360-degree view. It sits on a 190-million-year-old basalt lava flow atop a forested ridge between the Connecticut River and Greenfield that offers a splendid view of distinctive geological features of the River Valley.

Instructor: Prof. Richard Little