Travels in Geology: Roaming the rocky coastline of Downeast Maine

by Bethany Augliere
Monday, December 18, 2017

Jordan Pond was formed by an ice sheet during the Wisconsinan glaciation. A flat path that loops around the pond offers views of North Bubble and South Bubble, the two rounded hillocks seen in the distance. Credit: Bethany Augliere.

Sitting atop the bald, pink granite ledges of Cadillac Mountain in Maine’s Acadia National Park, I watched the sunset from the highest point along the North Atlantic seaboard. The expansive view reveals a stunning landscape carved from glaciers, with elongated lakes and ponds and rounded mountaintops in the distance. As the sky darkened, the moon rose above the horizon and over the nearby harbor. From this vantage point, on winter mornings from Oct. 7 through March 6, you can also catch the first glimpse of sunrise in the United States.

As a child, I liked visiting Maine for the moose sightings, blueberry picking and lobster rolls. I returned periodically over the years, mostly for hiking, wakeboarding and to spend time with family. Then during the summer and fall of 2016, I returned for a longer stay. I lived and worked from a small cabin on Pleasant Lake near the town of Alexander in “Downeast” Maine, a region that spans the northernmost stretch of the state’s coastline from Bar Harbor to the Canadian border. During that time, I explored hidden geologic gems down dirt roads as well as more popular spots in Acadia National Park, including a trail I hadn’t hiked in about 15 years.

The Rocks of Mount Desert

The oldest rocks seen today on Mount Desert Island, home to Acadia, are from the 500-million-year-old Ellsworth Schist (seen in both photos above). The next oldest are the sandstones and siltstones of the Bar Harbor Formation. The youngest rocks include myriad granites and other igneous rocks (right) between about 360 million and 420 million years old. Credit: all: Ron Schott.

Acadia National Park is situated mainly on Mount Desert Island, the largest of several thousand islands along the New England coast. The island rises 466 meters above a rocky shoreline, unlike much of the flat and sandy East Coast. With gorgeous lakes and craggy cliffs, it’s no wonder more than 3 million people visited the park in 2016, making it one of the top 10 most-visited national parks in the country.

The oldest rocks seen today on Mount Desert Island got their start about 500 million years ago during the Cambrian Period, when sediments and volcanic ash piled up on the seafloor of the Iapetus Ocean. Over time, pressure transformed the buried sediment into mudstones interbedded with ash layers. During the plate collisions and mountain-building events of the early Paleozoic that began raising the Appalachians, high temperatures and pressures recrystallized and folded these mudstones into the Ellsworth Schist, a metamorphic rock with wavy layers of minerals, including dark green chlorite and lighter layers of quartz and feldspar.

Eventually, the Ellsworth Schist was brought to the surface by further tectonic activity as mountain-building and continental accretions continued through the Ordovician. Exposures of the Ellsworth Schist can be seen today near the public boat ramp north of Bass Harbor on the southwestern side of the island, as well as along portions of the northwest shore of the island and on nearby Bartlett Island.

Mount Desert’s next oldest rocks — the Bar Harbor Formation — formed about 465 million years ago. These multicolored layers of sandstone and siltstone were, again, deposited as seafloor sediments, at least some during underwater landslides known as turbidity currents. Visitors can glimpse this sedimentary rock formation along the Shore Path in downtown Bar Harbor as well as near the east side of Sand Beach in Acadia National Park. Ash beds can also be seen in the layers of the Bar Harbor Formation.

The youngest rocks, which make up most of the island, are granites that intruded about 420 million years ago. Some smaller intrusions are thought to be about 360 million or 370 million years old. The predominant granites — the Cadillac Granite and the Somesville Granite — exhibit rich pink hues thanks to an abundance of orthoclase feldspar. Some are more fine-grained, having cooled quickly, while others are larger-grained with quarter-sized crystals, having cooled more slowly. There is also an igneous rock that has been described as “chocolate chip cookie dough-like” for its chunky appearance — this rock formed in a so-called shatter zone, where the heat from intruding magma fractured the existing rock above, creating chunks that were encased in an igneous matrix. Those chunks are pieces of Ellsworth Schist and Bar Harbor sedimentary rocks. Around the same time, large volcanic dikes formed in the area, leaving telltale dark bands of diabase protruding through the lighter-colored granites. Extrusive volcanism — likely resulting from the ongoing collisions and subduction in the area at the time — also spewed ash and lava, which became the rocks of the Cranberry Island Series.

What visitors see on Mount Desert Island today, however, is largely the result of hundreds of millions of years of erosion. The more than 400-million-year-old granites are exposed because all of the sediment and rock that once covered them has been eroded by wind, water and, more recently, ice. During the Pleistocene glacial advances, the area was covered time and again by enormous ice sheets. Most recently, the 1.5- to 3-kilometer-thick Laurentide Ice Sheet expanded from Canada to cover the state, and extended more than 450 kilometers out on the then-exposed continental shelf. As Earth’s climate began warming about 18,000 years ago, the ice sheet started to retreat north, leaving a glacially sculpted landscape in its wake.

Acadia’s Points of Interest

"Downeast" Maine encompasses the easternmost coastal part of the state, bordering Canada. Acadia National Park draws millions of tourists a year. Credit: both: K. Cantner, AGI.

Covering about 19,000 hectares, Acadia is relatively small for a national park, but given its rich geological history, you could spend weeks hiking its trails and shorelines and examining every feature. On the two weekends I spent in Acadia, I explored the park by driving Park Loop Road, a 44-kilometer-long route that winds through a large portion of the park on the eastern part of Mount Desert Island and has various pullovers at points of interest.

One of my main goals was to hike a specific trail that’s been a meaningful route in my family: the Precipice Trail, located on the east face of Champlain Mountain — which itself overlooks the eastern coast of the island — and is rated as the most difficult trail in the park. My mom hiked it with her grandparents when she was little, and her parents often hiked it too. When I was 14, my dad, little brother and I hiked it as well. Though it’s just a 4-kilometer loop, it requires a significant vertical climb to the summit of Champlain, the sixth-highest peak in the park at 323 meters above sea level.

View from the peak of Cadillac Mountain in Acadia National Park at sunset. Sunrise and sunset are popular times to climb the mountain. Credit: Bethany Augliere.

When I was 14, hiking the Precipice Trail was one of the most exhilarating and memorable experiences I’d ever had. We reached the summit by crawling over and under boulders, shimmying across ledges with steep cliffs to one side, and climbing iron rungs bolted into rocks. My dad was a tad nervous for my younger brother, and surprised that my mom sent us up the trail, unfazed. I think for all of us, part of the thrill was the surprise that this was more than just a wooded path up the mountain.

The author's hiking companion, Nico Ientile, takes a celebratory leap over some rocks after reaching the summit of the Precipice Trail. Credit: Bethany Augliere.

After my first experience, I tried without success to hike it again on periodic visits to Maine. (The park service closes the trail from mid-March to mid-August each year to protect a resident pair of breeding peregrine falcons.) In 2016, however, when I was living just two hours away from the park, I made a point to visit Acadia once the trail opened.

On a sunny day in late August, my companion, Nico Ientile, and I parked our car in the lot at the trailhead and began our vertical journey up the winding climb. I was excited to bring Nico on the trail that I’d told him so much about. We made it to the summit in about two hours, where, before heading back down, we rested and ate lunch overlooking the ocean to the east and Dorr Mountain to the west. If you’re in relatively decent shape, and not terrified by heights, it’s a fun hike. But it can be treacherous, and people have died, most recently, a 22-year-old college student who slipped and fell in 2012. The park service emphasizes that it is not a hiking trail, but a nontechnical climbing route.

There are plenty of more relaxing trails with scenic views throughout the park as well. For instance, a leisurely 5.6-kilometer walk around Jordan Pond offers views of the Bubbles, two small mountains rising above the pond’s north shore.

The Bubbles are examples of rche moutonée, asymmetrically sloped hills carved from bedrock by glaciers, with gently sloped sides facing the direction from which a glacier encroached and steeper lee sides. As glacial ice flowed over Mount Desert Island from north to south during the last ice age, it encountered resistant bedrock knobs that would become the Bubbles. The ice ground down and polished the north-facing, upstream slopes of these knobs, while also plucking chunks of bedrock from the downstream slopes.

A moderate hike up South Bubble offers stunning views of Jordan Pond, a glacially formed tarn, and also features a glacial erratic called Bubble, or Balanced, Rock. Credit: Bethany Augliere.

Both of these mountains have moderate trails up to their summits that make for nice day hikes. South Bubble is home to Bubble, or Balanced, Rock, a large glacial erratic, carried by the ice sheet and deposited at the cliff edge, where it seems to defy physics.

Other points of interest along Park Loop Road include Sand Beach, Thunder Hole and Otter Cliff. Sand Beach, the only natural sand beach on the island, is a pocket beach tucked in an inlet and flanked by the rocky shoreline on either side. On the east side of the beach, large boulders of gray Cadillac Mountain Granite mix with rusty-colored sedimentary layers from the Bar Harbor Formation and gray gabbro, the coarse-grained equivalent of basalt.

Sand Beach, tucked away in Acadia National Park, is one of the few sandy beaches in Downeast Maine; most are rocky. Credit: Nicodemo Ientile.

At Thunder Hole, wave action in a cove creates sounds like claps of thunder. The crashing waves can reach up to 12 meters high. Just a kilometer past Thunder Hole is Otter Cliff, a stunning 34-meter-high cliff that is one of the highest coastal headlands north of Brazil. To the north of the cliff, there’s a cove of rounded boulders dropped by glaciers and shaped by the constant wave action.

Exploring Elsewhere Downeast

The author's dog, Luka, sits on some of the orange-tinged rocks along the coast, just off Park Loop Road, in Acadia. In this stretch of the park, visitors can glimpse Sand Beach, Newport Cove and Great Head. Acadia, unlike most national parks, is dog-friendly. Dogs are allowed on many trails, rather than just in the campgrounds. Credit: Bethany Augliere.

Glacial striations on exposed bedrock indicate past glacial movement at Roque Bluffs State Park in Downeast Maine. Credit: Bethany Augliere.

When you leave Acadia National Park to explore farther north, the crowds begin to dwindle. The region is home to quaint fishing towns, state parks with trails along jagged cliffs and expansive views of the ocean, and an unusual phenomenon in which powerful tides create waterfalls that flow opposite to the current.

About two hours north of Acadia is Roque Bluffs State Park, a 111-hectare park featuring a rare sand beach that overlooks Englishman Bay. The beach formed as sediment collected from the erosion of a glacial moraine lying to the east. At the eastern end of the beach is a bedrock outcrop featuring glacial striations — etched linear grooves that preserve evidence of glacial movement.

Across the road from the beach, the 24-hectare freshwater Simpson Pond is a great spot to bird watch. Once you’ve had your fill of beach and pond views, several wooded trails that take you through local peatlands and bogs, as well as along Great Cove and Pond Cove, are worth checking out. The longest loop hike in the park is about 6.5 kilometers.

The nice thing about exploring outside of national parks is that sometimes you might be the only person at a location. That was the case when we visited Jasper Beach, an 800-meter stretch of beach tucked away in Howard Cove near Machiasport. Jasper Beach is named for its well-rounded reddish pebbles resembling jasper, a form of microgranular silica typically enriched with iron. However, few (if any) of the rocks at Jasper Beach are actually jasper; rather, these rocks are a fine-grained volcanic rock called rhyolite. The stones have been polished smooth by continuous wave action along the beach.

Constant wave action polishes the rhyolite rocks at Jasper Beach. Credit: Bethany Augliere.

At certain times of the year, a visit to West Quoddy lighthouse in Lubec, Maine, offers the first views of sunrise in the continental U.S. Credit: Bethany Augliere.

Helen's Restaurant in Machias is home to world-famous pies, and is definitely worth a visit. Credit: Bethany Augliere.

If you’re brave enough, take a plunge into the ocean here, though it may momentarily take your breath away. The water warms up to a refreshing 14 degrees Celsius in August, before cooling back down. You might catch the attention of curious harbor seals that often cruise along the shoreline. And if you’re looking to recuperate after your dip, or if a bite to eat sounds good, Helen’s Restaurant in the nearby town of Machias is the perfect place to get dinner. Be sure to save room for dessert, because Helen’s is nationally recognized for its homemade pies, like blueberry cream and raspberry cream, both of which have a thick layer of fresh berries beneath a mound of whipped cream.

One of my favorite features of Downeast Maine is the Bay of Fundy, which runs from the northeastern tip of Maine up the Canadian coast between New Brunswick and Nova Scotia. The bay is home to the largest whirlpool in the Western Hemisphere, called Old Sow, which spans 76 meters across and 12 meters deep. The bay also hosts more than a dozen species of marine mammals, and has the highest tidal ranges in the world — up to 16 meters.

One way to appreciate the bay — and maybe see Old Sow, which is located in Passamaquoddy Bay between Moose Island in Eastport, Maine, and Deer Island in Canada — is by boat or ferry. There are many different whale- and wildlife-watching tours, as well as ferries that will transport you and your vehicle over to Canadian islands like Campobello and Deer Island

Nico and I decided to take a whale-watching tour when we heard there were up to 20 endangered right whales in the bay. Fewer than 500 of these animals remain in the wild. Unfortunately, they often get struck by ships or become entangled in derelict fishing gear. On our trip, we saw minke whales, fin whales, bald eagles, harbor porpoises, harbor seals and, indeed, right whales, which were in deepwater beyond the channels between the Canadian islands and U.S. mainland.

In the Bay of Fundy, an endangered North Atlantic right whale breathes at the surface, displaying its iconic V-shaped spout, with the Canadian Grand Manan Island in the distance. Credit: Bethany Augliere.

At Quoddy Head State Park, visitors can glimpse the lighthouse and views across the bay, as well as hike through wooded trails along the cliffs. Credit: both: Bethany Augliere.

If you’re less inclined to go out on the water, which can be bumpy, cold and enveloped in fog, there are still plenty of places to explore in the area. After eating lunch in the small fishing town of Eastport on Moose Island, we decided to hike through nearby Shackford Head State Park, where we had the trails on this scenic headland all to ourselves. Multiple options are available to hike the island, including a short trail that leads down to the shore at the end of the peninsula. Another path takes you through the woods of the peninsula, which are filled with aspen, beech and maple trees. Whichever way you take through the park, you’ll see stunning views of the Canadian Campobello and Grand Manan islands, Cobscook Bay and Deep Cove, and some aquaculture pens for farmed salmon. In late summer, you can pick wild blueberries on the ledges.

From the cliffs of the park, you’ll see a candy-striped lighthouse, another site worth exploring. If you missed the U.S.’s first sunrise of the day at Cadillac Mountain, you can catch it at Quoddy Head State Park, the easternmost point in the continental U.S. and a 10-minute drive from the town of Lubec. The park is home to a photogenic red-and-white striped lighthouse commissioned by President Thomas Jefferson and built in 1808. Visitors can explore the rocky beach, visit a cranberry bog or hike the coastal trail.

Meanwhile, just a few minutes' drive north from Eastport, you’ll find a rough-cut red granite stone marking the 45th parallel, the invisible line around Earth that’s halfway between the equator and the North Pole. Nearby, there’s the famous 45th Parallel gift shop, opened in 1994, where you can pick up souvenirs to mark the occasion of your visit.

From either Lubec or Eastport, a 30- to 40-minute drive will take you to Reversing Falls Park. Here, the dramatic tides surge in and out of Dennys Bay and Whiting Bay, shifting the water level by 6 meters every 6.5 hours. During the incoming tide, water rushes into the bays through a narrow channel, the current creating deep whirlpools and standing waves.

As the direction of the tide begins to change, the rushing water calms to almost a standstill. Then, as the tide recedes, the rock ledge in the center of the channel is uncovered and appears to have a waterfall moving in the opposite direction of the current.

Water rushes through the narrow channel during the tide change at Reversing Falls Park in Pembroke, Maine. Credit: Bethany Augliere.

It’s best to time your visit for high tide, which changes daily, and to give yourself plenty of time to find the parking lot beforehand, since the route there takes you down dirt roads with only a wooden sign marker to direct drivers toward the lot. Then you need 20 to 30 minutes to walk to a vantage point from which to watch the water. Once you find a place to relax, you can watch the harbor seals playing in the current and bald eagles flying overhead. If you want to see the entire sequence of events during the tide change, plan to spend a few hours. Some people bring chairs and pack a picnic meal.

There’s still much more to explore in Downeast Maine, but in my travels here, I’ve definitely gotten a taste of what this distinctive region has to offer, and a new appreciation for the state’s coastal geology. Maine is much more than moose, blueberries and “lobstah” rolls.

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