This sample from Juneau, Alaska is a “surf and turf” sand with both rock grains from the land and marine-life fragments from the sea.
The Mendenhall Glacier, one of North America’s largest ice fields, drains into Auke Bay, north of Juneau. As the glacier journeys to the sea, it scours and transports rocks from the jagged peaks and valleys, including orange/brown granite and clear quartz. In addition, this beach sand includes fragments eroded from the shoreline. These land-based grains compose the “turf” components of the beach.
The “surf" grains in this sand are shell fragments from marine invertebrate species that inhabit the local waters. The blue fragments are from mussels. The chalky white pieces are fragments of barnacles plates which form their hard calcium body. The striated green rod is a sea urchin spine.