Retreating Juneau Glacier Reveals 1200 Year Old Trees
By Paul Homewood
h/t Ice Age Now
As the Juneau Glacier retreats in Alaska, geologists are finding the remains of ancient forests, dating from various periods between 2350 and 1200 years ago.
The Juneau Empire reports:
The Mendenhall Glacier’s recession is unveiling the remains of ancient forests that have remained frozen beneath the ice for up to 2,350 years.
UAS Professor of Geology and Environmental Science Program Coordinator Cathy Connor said she and others have been tracking the emergence of the forests’ remains. Some stumps and logs can be found in the moraines around the west side of the glacier. Some remain vertical, frozen to the ground in ice caves. Some are scoured smooth; some still have their bark. All are packed with silt in the outer layers.
As the glacier advanced, it snapped off the tops of the trees in its path, Connor said. The stumps were buried — and protected — in gravel.
Now, as the glacier melts, the melt water carves out paths in that gravel, revealing the remains of the trees.
The most recent stumps she’s dated emerging from the Mendenhall are between 1,400 and 1,200 years old. The oldest she’s tested are around 2,350 years old. She’s also dated some at around 1,870 to 2,000 years old.