Overview

Glacier’s stromatolites date from the Precambrian era - some 1.5 billion years ago - when layers of blue-green algae formed bacterial mats in the warm, shallow sea bottoms that covered what is now Glacier National Park. Sometimes referred to as “sliced cabbage” due to their concentric ring formations, these algae mounds were responsible for providing earth with much of its oxygen rich environment, through the process of photosynthesis; at the time, carbon dioxide dominated the atmosphere. Today, paleontologists from around the globe travel to Glacier Park to study the stromatolites. Living colonies can still be found in reefs around the Bahamas and Australia.

Locations

Stromatolites are mainly located at high elevations, in the east side of the park. The Altyn and Siyeh Formations provide excellent examples of these historic geoligical records. Productive viewing areas are along the east side of Going To The Sun Road, on Logan Pass, and near Grinnell Glacier. Stop in at a ranger station for more information and locations.

Season

Summer is the best time to view stromatolites as snow cover will be absent or minimal. Due to their location at high elevations, access will often be contingent upon Going To The Sun Road accessibility and trail conditions.

Activities

Hiking: To view stromatolites, visitors must often incorporate a hike as part of their excursion. Take the popular hike to Grinnell Glacier, keeping your eye out for these fossils:

• Trailhead: Grinnell Glacier Trailhead
• Trailhead Location: Near Many Glacier Hotel
• Distance: 6 miles (one-way)
• Ascent: 1600 feet
• Difficulty: Easy - Moderate

Photography: Stromatolites might well be one of the oldest structures you ever record on camera!