9 Landscape Treasures Left Over From the Ice Age

Glaciers reshape landscapes and transform the earth when they move. As they advance, they erode bedrock and scoop out basins and valleys. As they retreat, they leave behind piles of debris and rock that can become hills and mountains. After a glacier is gone, things never look quite the same.

The last ice age is no exception. During this glacial period, ice sheets covered North America, northern Europe, and Asia. Evidence of their era, which ended 11,000 years ago, can be found all around the world. You may even have one or more of these glacial landforms in your neck of the woods or very nearby.

Here are nine landscape treasures that have been around since the last ice age.

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Moraines

Buildup of glacial-era dirt and debris in Borrowdale — Freddie Phillips / Flickr / CC BY 2.0

As glaciers retreat, they leave piles of rocks and debris that they once carried. The accumulation of debris makes up a moraine. It's formed in a number of ways, including along the sides of glaciers (lateral moraines), beneath glaciers in meltwater streams (ground moraines), and where glaciers came to an end (terminal moraines). Today, moraines typically look like hills and ridges ranging from small mounds to super-sized hills hundreds of feet high. They often exist in clusters where receding ice is deposited pile after pile.

Notable moraines include Wisconsin's Kettle Moraine, New York's Harbor Hill Moraine, Massachusetts' Cape Ann Peninsula, Dogger Bank (once a landmass connecting Britain to Europe), Canada's Oak Ridges Moraine, and those in Britain’s Lake District.

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Cirques

Large ravine covered in ice and snow against blue sky — Msheppard / Wikimedia Commons / CC BY-SA 3.0

Erosion from moving ice age glaciers scooped out many amphitheater-shaped mountain valleys called cirques. These basins are typically encircled by high cliffs on three sides with an open section on the downhill side (aka "the lip") where the glacier once flowed away. Imagine a tilted bowl.

Cirque stairways are a succession of cirques sitting one above the other like steps. Zastler Loch in Germany's Black Forest is an example of a cirque stairway with three glacially carved basins.

Other notable cirques include New Hampshire's Tuckerman Ravine, Wyoming's Cirque of the Towers, Scotland's Coire an t-Sneachda, and Poland's Sniezne Kotly.

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Tarns

Fill a cirque with rain or stream water and you have a tarn. These small mountain lakes often feature a moraine at one end that acts like a dam. One of the most well-known areas for ice age tarns is Britain’s Lake District. This region has even spawned a new sport called tarnbagging, in which lake lovers traverse rugged countryside to visit as many tarns as possible.

Lake Ellen Wilson in Montana's Glacier National Park is a tarn, as is New York's Lake Tear of the Clouds, Nevada's Verdi Lake, and Slovakia's Vel’ke Hincovo.

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Eskers

Cousins of moraines, eskers are deposits of sand and gravel. They form in long, winding, serpentlike ridges where debris-laden meltwater once gushed through ice-walled tunnels inside and under retreating glaciers. When the tunnels melt, sediment is deposited in snaking mounds that mark where the streams once ran, often for hundreds of miles. Many highways, including the Denali Highway in Alaska and the “Airline Highway” segment of Route 9 in Maine, are built on top of ice age eskers to cut costs.

Famous eskers can be found in Massachusetts' Great Esker Park and at Michigan's Mason Esker, Scotland's Kemb Hills, the Thelon Esker between Canada's Northwest Territories and Nunavat, Sweden's Uppsalaasen, and Esker Riada (a system of eskers stretching across the center of Ireland).

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Grooves and Striations

Glacial striation on rock at Mount Rainier National Park — Walter Siegmund / Wikimedia Commons / CC BY 2.5

As glaciers plowed down mountains and across landscapes during the ice age, gravel and stones carried by the ice often abraded the bedrock beneath like sandpaper. What remains are scratches, grooves, and gouges usually laid out in multiple long parallel lines that follow the direction the ice once flowed.

Notable examples can be found in Glacial Grooves Geological Preserve on Kelleys Island in Ohio, Washington's Mount Rainier National Park, Montana's Glacier National Park, Michigan's Isle Royale National Park, and at Utah's Lake Blanche and Canada's Hawkes Bay.

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Kettle Lakes

Tranquil blue Walden Pond surrounded by trees in autumn — Amy Meredith / Flickr / CC BY-ND 2.0

Thousands of prehistoric pools, left by retreating glaciers some 11,000 years ago, dot North America, northern Europe, and other formerly ice-covered landscapes around the world. These kettle lakes formed when giant ice chunks broke off as glaciers receded and were surrounded or covered by stones, soil, and other debris flowing from the meltwater. When the ice chunks finally melted, what remained were bowl-shaped holes called kettles. Over the millennia, many filled with water from precipitation and streams to form lakes and ponds.

Notable kettle lakes include Walden Pond (Concord, Massachusetts), Lake Ronkonkoma (Suffolk County, New York), Lake Annette (Jasper National Park, Alberta, Canada), and Seeon Lakes (Bavaria, Germany).

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Kames

Glacial kame covered in trees in golden fall colors — Royal Broil / Flickr / CC BY-SA 2.0

These irregularly shaped hills and mounds are similar to moraines and other elevated glacial formations, but they were created in a slightly different way. As glaciers dissolved, depressions and crevasses often formed in the ice and filled with meltwater carrying rocks and gravel. The debris in these holes finally reached the land below and was deposited in a lump.

Kames tend to show up in irregular spots and may not be near other kames. However, they are often associated with kettle holes (referred to as kame and kettle topography).

Find these at Ontario's Minnitaki Kames Provincial Park; Mendon Ponds Park near Rochester, New York; and Sims Corner Eskers and Kames National Natural Landmark in Washington.

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Drumlins

Mound in the distance with rippling sand in foreground — Brendanconway / Wikimedia Commons / Public Domain

Like other glacial hills, these elongated teardrop-shaped mounds formed from sand, gravel, and rock left by melting glaciers. However, unlike moraines, kames, and eskers—which are geologic junk piles left in the wake of glacial meltwater—drumlins were likely created by the ice itself in a process that scientists don’t fully understand.

They are always rounded with a higher snout side pointing up and a tail side stretching back and down. Drumlins often exist in vast fields with all of them running parallel to the direction the ice once moved. Drumlins flooded by the sea turn into islands, called drowned drumlins.

Massachusetts' Boston Harbor Islands National Recreation Area, Ireland's Clew Bay, Wisconsin's Smith-Reiner Drumlin Prairie, the Finger Lakes region of New York, and Ontario's Peterborough Drumlin Field provide examples.

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Glacial Erratics

Glacial erratic under a blue sky with white clouds — Coaxial at English Wikipedia / Wikimedia Commons / CC BY 3.0

Ever noticed a giant boulder that looks completely out of place and different from other rocks around it? It may be a glacial erratic, a large stone (some as big as a house) transported by glacial ice for hundreds of miles or carried on ice rafts that broke away during glacial flooding. Either way, these dramatic glacial gifts abound.

Notable ones include Massachusetts' Plymouth Rock, New York's Indian Rock, the U.K.'s Norber Erratics, Washington's Fantastic Erratic in Cougar Mountain Regional Wildlife Park, Ireland's Clonfinlough Stone, and Canada's Big Rock in Alberta.