Pictured Rocks National Lakeshore, Munising, Michigan

For Jim's 71st birthday I booked us a cruise on the Pictured Rocks Cruises to see Pictured Rocks lakeshore. It would be virtually impossible to see these rock structures from the shoreline, as you will see from the pictures, you can see the rock structures best from the deck of a boat. Pictured Rocks National Lakeshore is between Munising and Grand Marais along Lake Superior in Michigan's Upper Peninsula. It is America's first National Lakeshore with beaches, 10 inland lakes, and nearly 100 miles of trails.

I usually go to a Visitor Center to get more information on the places we visit, however, our cruise was leaving at 2pm and we did not get going until late, and by the time we got back from the cruise it was after 4pm. When we did get to one Center, it was being renovated and there was just a small construction trailer where the temporary center was housed, so there was no information on the lakeshore. I should have gone to the interpretation center next to the cruise office.

Pictured Rocks offers a stunning mix of colored cliffs, deep northern forest, miles of beaches, immense sand dunes, tall waterfalls, hiking trails, and much more. You really could spend many days at the lakeshore, but since we were camping 35 miles from it, we only went one day. 

The different colors of the water indicate its depth. The light blue is very shallow, about 4 feet deep. Where you see the dark blue, the floor falls away to 65 feet and deeper.

There are companies that provide guided kayak trips along the Pictured Rocks. These companies can be found through the NPS website under Plan Your Visit > Things to do.

Miners Castle

Erosion over long periods of time has created the interesting rock formations that give this place its name. A rockfall in 2006 dramatically changed the look of Miners Castle as one of its two turrets unexpectedly fell into the lake.

The colorful Pictured Rocks sandstone cliffs are located in the western third of the park. They extend from Sand Point northeast along the shore for about 15 miles. 

The name "Pictured Rocks" comes from the streaks of mineral stain that decorate the cliffs. Stunning colors occur when groundwater oozes out of cracks and trickles down the rock face. Iron (red and orange), copper (blue and green), manganese (brown and black), and limonite (white) are among the most common color-producing minerals.

Colorful and bold, the Pictured Rocks cliffs tower 50 to 200 feet above Lake Superior. These sandstone cliffs stretch for about 15 miles along the lake from Sand Point on the west to just after Spray Falls on the east. The most colorful portion of the cliffs begins east of Miners Beach.

The name "Pictured Rocks" comes from streaks of mineral stain that decorate the face of the weather-sculpted sandstone. Stunning colors occur when groundwater oozes out of cracks and trickles down the rock face. Iron (red and orange), copper (blue and green), manganese (brown and black), and limonite (white) are among the most common color-producing minerals.

Petit Portal arch, also known as "Lover's Leap"

Tree Topped Cliffs

The geologic formations of Pictured Rocks National Lakeshore are most spectacularly represented by the 50-200 ft. sandstone cliffs that extend for more than 15 miles along the shoreline. Sea caves, arches, blowholes, turrets, stone spires, and other features like the famous Chapel Rock have been sculpted from these cliffs over the centuries by unceasing waves and weather.

A Tapestry of Geologic Layers
Geologic history recorded in the sedimentary rocks and surficial deposits of Pictured Rocks National Lakeshore is limited to two widely separated intervals of geologic time, the Late Precambrian, Cambrian, and Early Ordovician Periods (500-800 million years before present), and the Late Quaternary Period (two million years before present to the present).

During the Cambrian and Early Ordovician periods, sediments were deposited in the shallow seas and near-shore deltas that covered what is now northern Michigan. These deposits became the sandstone layers that are exposed within the lakeshore. Except for their exposure near Lake Superior, these layers are presently covered by a veneer of Quaternary glacial drift.

Bedrock is best observed in the western one-third of the park where cliffs rise up from Lake Superior. These extend along the lake about from Munising to Beaver Basin. For a short distance inland from the escarpment, bedrock is occasionally exposed.

The Jacobsville Formation, of Late Precambrian age, is the oldest formation exposed in the lakeshore. It is a river/lake deposited, feldspar-rich quartz sandstone, deep red in color with white mottling. Only the top few feet of this formation rise above lake level within the lakeshore; east of Hurricane River Campground, at Au Sable Point, and the gorge at Sable Falls. Due to its attractive color, Jacobsville sandstone was quarried on nearby Grand Island for building stone in the late 19th century.

The Mid to Late Cambrian, light grey to white Munising Formation lies unconformably above the Jacobsville. The Munising Formation probably represents a complex shoreline/shallow water environment that was influenced by river, wave, tidal, and wind processes. The Munising is divided into three members: the basal conglomerate, the hard Chapel Rock sandstone (characterized by large, sweeping cross beds), and the crumbly Miners Castle sandstone.

Capping the easily eroded Miners Castle Member of the Munising Formation in the western half of the Pictured Rocks, is the resistant Early Ordovician Au Train Formation. The Au Train Formation is a light brown to white dolomitic sandstone that lies above the distinctive caprock above the lip of Munising and Bridalveil Falls. This harder sandstone is responsible for the presence of so many of the area's waterfalls, as it resists erosion better than other formations.

Grand Portal Point

Little Portal Point

During the Pleistocene epoch, ice sheets of all four North American glacial stages advanced and retreated through the area. The Valders advance, one of the last substages of the Wisconsinan glacial period, wiped the surface clean and left only its record about 12,000 years ago. A brief re-advance of ice, the Marquette substage, occurred 10,000 years ago in northern Upper Michigan.

Melting of glacial ice within the Superior Basin produced huge rivers that deposited millions of tons of pulverized rock rubble in various configurations to the south of the Superior basin. A sheet of outwash, of varying thickness, was deposited along the south edge of Pictured Rocks National Lakeshore between Wetmore and Seney by southward flowing "braided" glacial streams. The material underlying the present-day Kingston Plains was deposited in this way. Kingston and Nevins lakes are examples of "kettle hole lakes" within the outwash. The Grand Sable Banks near Grand Marais perhaps originated as deposits from a river of glacier meltwater or as a kame terrace (a flat-topped mound or hill composed of sorted sand and gravel deposited by meltwater in a former glacial lake.)

Meltwater carved several channels into Cambrian sandstone bedrock; the most prominent of these are now occupied by Chapel Creek and Mosquito River and by Beaver Basin. As ice retreated completely from the Superior Basin, water levels in the basin receded rapidly northward leaving the Pictured Rocks area "high and dry" about 9,500 years ago. This occurred as outlet channels to the east remained at low levels due to the weight of glacier ice pressing down on the land.

Between 6,000 and 4,000 years before present, "isostatic rebound" of the earth's crust from its "depressed" state began to accelerate as land was relieved of the huge weight of the ice sheets. The rise of the outlet of ancestral Lake Superior (at North Bay, Ontario) caused lake level to rise relatively quickly to a level roughly 13 m (40 feet) higher than present Lake Superior. This high lake stand has been designated Glacial Lake Nipissing. Slowing of rebound, downcutting of channels through unconsolidated material, shifting of outlets to the south, and climatic change subsequently caused a lowering of Lake Superior to near its present level.

As lake levels rose about 5,000 years before present, the Grand Sable Banks were destabilized and part of the glacial river deposit was reworked by wind to form the Grand Sable Dunes. During the Nipissing "high stand," Chapel Rock and Miners Castle as well as many less prominent features were carved into the Cambrian sandstone by wave action. Certain inland lakes within the national lakeshore (Beaver, Trappers, Little Beaver, Chapel, Little Chapel, and Miners Lakes) were originally bays on ancient Lake Nipissing.

As erosion lowered the Lake Nipissing outlet to the modern Lake Superior level during a 1,600 year period, lake currents deposited a succession of parallel beach ridges from the Nipissing level to the present beach. These closely spaced ridges, which form a "corrugated plain," are evident in the vicinity of Au Sable Point, along the trail from Little Beaver Lake Campground to Lake Superior, on Sand Point and on the tombolo (sand connection) between Trout Bay and Murray Bay on Grand Island.

Battleship

Battleship Row

"Lake Superior possesses all the sublimity of the ocean. In gazing upon its surface, whether stretched out like a vast mirror, reflecting the varying tints of the sky, or ruffled by gently–curling waves, or lashed by the fury of the storm, the beholder is alike impressed with a feeling of the grand and the infinite." ~~ J.W. Foster and J.D. Whitney, geologists, 1850.

Lake Superior is the dominant force affecting Pictured Rocks National Lakeshore. This powerful inland "sea" creates its own weather and climate, resulting in cooler temperatures in the summer and milder temperatures in the winter. Waves continually sculpt the cliffs and reshape beaches, but the effect of Lake Superior is also felt far from shore. Storms, snow, fog, humidity, temperatures, and wind generated from the lake impact every park ecosystem.

Lake Superior is the largest, coldest, and most pristine of the Great Lakes. It has the largest surface of any freshwater lake on earth and it is the third largest lake by volume. Its striking clarity is due to a low amount of organic material. Lake Superior is oligotrophic, meaning it is nutrient poor. The surrounding forests and rock layers filter water entering the lake, which limits the amounts of phosphorus and various biological nutrients needed for algae and other plant growth. Despite this, the lake supports a healthy ecosystem of plankton, invertebrates, and cold water fish.

The Captain took us into this small alcove where the water was dripping off the top of the cliff. It was very narrow and he did a great job slowly heading in and then backing straight out.

Lake Dynamics
The lake doesn't have true tides but it does exhibit an interesting movement of water called a seiche (SAY-sh). A seiche is a stationary or standing wave that oscillates back and forth like a pendulum in an enclosed body of water. Seiches are typically caused when strong winds and rapid changes in atmospheric pressure pile up water on one end of a lake. When the wind stops, the water rebounds to the other side, often causing water levels to rise quite quickly. (Striking video footage shows a seiche in action along Superior's Ontario shore.)

Small seiches are quite common and usually unnoticeable. Larger seiches can resemble storm surges that flood beaches and inundate boat docks. Generally seiches take about eight hours to cross the lake and come back again, sometimes resulting in changes in nearshore waters as much as three feet or more. Recent studies show that seiches are an important mechanism for distributing nutrients from deeper water into the sunlit surface levels where they are needed for phytoplankton growth.

Another important dynamic of Lake Superior is stratification, or layer formation. All lakes, large and small, undergo this process in some fashion. Water tends to separate into horizontal (and sometimes vertical) density layers that resist mixing. Density is related to temperature, so that when summer heat warms the upper layers of the lake, the lower colder layers are denser in comparison. In winter, the coldest layer (ice) lays above slight warmer layers beneath.

As the lake loses heat in late fall, the surface waters cool and the density between layers becomes increasingly similar. When the density is similar enough, a windstorm can mix the entire lake, an event called lake turnover. The same process happens in the spring as the water heats up. Turnover is extremely important for distributing nutrients and oxygen throughout all parts of the lake.

Chapel Rock

Spray Falls

Impacts on Pictured Rocks National Lakeshore
Lake Superior affects Pictured Rocks in many different ways. Cool temperatures and moisture generated by the lake create microhabitats that support plants generally found farther north. Fog and mist promote growth of moss and lichens on the cliffs. Continual moisture reduces the risk of forest fire. Windstorms blow down trees close to shore, affecting forest structure. Currents carry sand that reshape spits and beaches. Lake levels may change as much as a foot from one year to the next, which can swallow up beaches and cause more rock erosion when levels are high.

Lake effect snow has a great impact, favoring some wildlife species and making survival harder for others. Large snow drifts shelter smaller animals like mice while making it more difficult for deer and larger mammals to travel through. Deep snows protect certain plant species and replenish groundwater supplies. Cool summers reduce evaporation in the shallow wetlands that form when snow melts, thus allowing greater numbers of mosquitoes to hatch.

Although Lake Superior has little visible pollution, chemical contaminants such as mercury and PCBs are present. The primary source for these and other pollutants is atmospheric deposition. Non-native species are also of concern. Invasive fish, particularly sea lampreys, can be found in nearshore waters. Sea lampreys swim up rivers to spawn, and visitors report seeing young lampreys near the mouths of rivers and streams in the park. So far zebra and quagga mussels have not had a major impact on Lake Superior, as the lake is too cold and oligotrophic (nutrient-poor) for them to thrive.

Chapel Rock

Old Lighthouse

After the cruise, we drove to Munising Falls, which is where I thought I could get to see a Visitor's Center, which I discovered was closed for renovation. So, we stayed and walked to the falls to see what they were like.

This is what Munising Falls used to look like. The Schoolcraft Blast Furnace manufactured pig iron at this site for nearly ten years, beginning in 1868. Steam engines powered by water from Munising Creek provided the "blast" (hot air) needed to turn iron ore, limestone, and charcoal into pig iron. Much of the iron was used for railway ties or as an additive for other metals. At its height, the furnace produced as much as 35 tons of pig iron per day. But eventually supplies of ore and charcoal ran out, forcing the furnace to close in 1877.

The iron industry employed almost half the town of 1000 residents. When the furnace shut down, the town hit hard times and many residents left to seek work elsewhere. In 1901 the idle machinery was sold, melted down, and recast for other uses. Not many signs of industry are left. The smoke and din of a once busy iron town have vanished into the past. All that remain are some piles of rock rubble, a few flakes of slag, and memories of this distant enterprise.

With its job of serving industry operations long over, the water from Munising Falls now flows freely into Lake Superior. The waterfall, fed by a natural spring a few miles back from the top of the ridge, continues to carve the sandstone deeper and wider over time. Pine, Hemlock, Cedar and other trees along the creek produce tannins that darken the water to a tea-brown color. Natural foam is frothed and swirled by the current. The forest has reclaimed this site, creating new habitat for wildlife and offering beauty year-round to those who visit.

The amount of water flowing from the falls looks like its diminished quite a bit. It could be due to lack of rain, but I don't know.

I did notice that there is a rock wall that was built next to the stream all the way from the falls down the walkway.