Bubble Pond
What’s there to find?
Follow the Park Loop Road and make your way to a beautiful and easily accessible site with a gorgeous view telling the stories of super volcanoes and glaciers.
Start your walk around the pond with a view of Cadillac Mountain on your left and Pemetic Mountain on your right. Wonder off on the nice trail and enjoy Acadia!
Directions to Bubble Pond
North
3.2 Km
Taking a closer look at the outcrops of bedrock you will find the Cadillac Granite. This is a 420 million year old rock with a story. The boulders and till you encounter on your way around the lake, are glacial erratics deposited by the glaciers that left the region 18,000 years ago.
15 Centimeters
The Rocks and Minerals
Rock
The Bedrock is the Cadillac Mountain Granite (Dcg on the Geologic Bedrock Map (Gilman and Chapman, 1988)) which is made of quartz, potassium feldspar, and hornblende. The Cadillac Mountain Granite is Phaneritic meaning all these mineral crystals are about the same size (5 mm across).
It can be identified by its pink colour which can easily be seen in this image.
Till
The till at this site was pushed here by glaciers about 18,000 years ago. It's a mixture of sand, silt, clay, and stones. On the Surficial Geologic map it's labeled Wt (Lowell, and Borns, 1988).
How Did This All Form?
Cadillac Mountain Granite
420 million years ago a large magma chamber developed under MDI (Braun, D., Braun, R., 2016). The Cadillac Granite intruded into the magma chamber at a depth of two or three miles below the surface. While not all of the magma was expelled, the magma that stayed inside the earth cooled slowly. It cooled slowly enough that crystals were able to form in a phaneritic (similar) size. The crystals were all about 5mm in diameter. The magma chamber eventually over pressurized and erupted and shattered the rock on the top and sides of the chamber followed by creating a ten -mile-wide caldera. Guide to the Geology of MDI and Acadia National Park (Braun, D., Braun, R., 2016). After many years of erosion, the granite was exposed as we know it today.
Taking a look at the fractures in the bedrock near Bubble Pond, you can estimate that the main fractures trend in a north-south direction. These fractures are planes of weakness that are easier eroded and more vulnerable to glaciers. When the last glacier moved from north to south over this region 18,000 years ago, it therefore eroded the depression in the landscape, where you find the Bubble Pond today.
Fun Fact! If you pay close attention to the direction of lakes on a map of Mount Desert Island, you will notice how most lakes go in the same direction as Bubble Pond. This suggests that many of the fractures go in the same direction as well, meaning that they might all have formed during the same tectonic events.
Everything within this range is north (315° - 45°)
0°
90°
270°
180°
Orientations of Major Bodies of Water on MDI
Seal Cove Pond
0°
Long Pond
345°
Echo Lake
355°
Jordan Pond
345°
Eagle Lake
4°
Bubble Pond
345°
North
Many of the major bodies of water on MDI including Bubble Pond are oriented north-south. Their long axis all fall within 315° to 45°. This is the same orientation of a major fracture set on the island which includes the orientations:
341, 341, 346, 345, 348
North
What Did the Glaciers Do?
The Last Glacial Maximum was 18,000 years ago
Taking a look at the mountains surrounding Bubble Pond, as well as the Porcupine Islands in Frenchman Bay, you will notice how they all have a gently slope of the northern side, and a steeper slope on the southern side. As the glacier pushed over the land, it created striations (grooves in the rock that show the direction of glacial movement).
When the glacier ran into a mountain, the ice compressed. It was put under more pressure as it went up the mountain, causing the base of the glacier to melt slightly. Then, once the glacier got over the peak, the ice started to expand again. Under less pressure, the ice froze to the rock it was on, plucking the rock from the mountain and taking it with it. This caused the side that the rock advances on to be much smoother, while the side that got plucked to be much more jagged and steeper. This form of mountain is called Rochê Moutonnee.
A hand drawn sketch explaining how the glacier moves over the mountain and shapes it in the Rochê Moutonnee landform.
A picture of the Pemetic Mountain seen to the right of Bubble Pond. The southern side of the mountain is to the left in this picture. Here you can see how the slope on the southern side where rocks were plucked off is steeper than on the northern side of the mountain where the surface was abraded.
Why is there Water?
Underground, there is a level of groundwater where if you dig far enough down, the hole you made will fill with water. This is how a well works. You dig a hole far enough down, and the hole will fill with water, allowing you to then bring water up from there. Bubble Pond works the same way. When the glaciers passed through the area, they took rock out from weakened points between fractures. This left a hole in the ground. This hole then filled with water, creating the pond as it is today.
Why is This Site Important to Experience on Mount Desert Island
- You get a great view of the Cadillac Mountain.
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You get to walk in the very depressions carved out by glaciers 18,000 years ago.
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It’s a beautiful picnic spot!
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If you take a look at the granite bridge right next to the parking lot, you might also become curious about the long history of quarrying on the island, and might even want to visit the local granite museum! Check out their website:
References:
Gilman, R. A., and Chapman, C. A., 1988, Bedrock Geology of Mount Desert Island: A Visitor’s Guide to the Geology of Acadia National Park: Maine Geological Survey
Braun, D., and Braun, R., 2016, 2012 Revised Mount Desert Island Bedrock Geology Map Explanation: https://www.coa.edu/shall/Geoscience/Maps_and_Links_files/2012%20Revised%20MDI%20Units.pdf (accessed September 2017).