Having once inhabited most of the United States, mountains lions were extirpated from eastern and central portions of our country by the early 20th Century; an exception was the Florida panther, which managed to survive in the dense vegetation of the Everglades and adjacent cypress swamps. Throughout most of the 1900s, the easternmost populations of cougars (other than the Florida panther) were in West Texas and in the Black Hills of western South Dakota.
However, over the past decade, sightings of mountains lions have increased signficantly across the American Midwest. Almost all of the confirmed cases have been males, presumably banished from their home range by other dominant males; indeed, cougars are territorial and field studies have revealed that the home range of adult males is in the neighborhood of 100-300 square miles. While 5 mountain lions inhabited the Pine Ridge Escarpment of western Nebraska in 2004, 30 were documented by 2011, including females and cubs. Sightings in Kansas, Missouri, Iowa, Minnesota and Wisconsin have involved male cougars that are thought to have wandered eastward from South Dakota and western Nebraska (though some may have arrived from Colorado via the Arkansas River corridor). One famous case involved a male that wandered through Minnesota and Wisconsin in 2009-2010 and ended up getting killed in Connecticut in 2011. Here in Missouri, there have been at least 29 cougar sightings since 1994, though, in some cases, multiple sightings of the same cat may have occurred. Since mountain lions are secretive and primarily nocturnal, an accurate estimate of Midwest wanderers is very difficult to obtain and it is likely that more pass through this region than some human residents might care to imagine; on the other hand, livestock loss to cougars has been minimal since these travelers seem to favor small mammals and the occasional deer.
Of course, unless females begin to follow the nomadic males from mountainous areas of the West, breeding populations will not become established in the Heartland. The increasingly common sightings in recent decades surely reflects the growth of human populations throughout the Mountain West, depriving these predators of their natural habitat and forcing males to head east, following river channels across the Great Plains. Any excitement associated with the opportunity to observe these magnificent cats in the Midwest is tempered by the knowledge that we have driven them from their modern homeland and that they are returning to an ancient homeland that has forever changed. Whether they will be welcomed or persecuted remains to be seen.
Tampilkan postingan dengan label Great Lakes. Tampilkan semua postingan
Tampilkan postingan dengan label Great Lakes. Tampilkan semua postingan
Jumat, 25 Mei 2012
Jumat, 18 Mei 2012
Superior's Northwest Coast
Just north of downtown Duluth, Interstate 35 ends and becomes Minnesota Route 61 that hugs the northwest coast of Lake Superior, all the way to the Canadian border. Providing spectacular and ever-changing views of the lake, this road also yields access to a chain of State Parks, most of which surround rivers that rise in the hill country to the west and rumble down to Lake Superior.
A few of these Parks deserve special mention. Gooseberry River State Park, a few miles north of Two Harbors, is accessed by an excellent network of trails that lead past a series of beautiful waterfalls, lead out to cliff-top views of the lake and river valley or take the visitor down to the rocky shore. Temperance River State Park, just north of Taconic Harbor, provides spectacular evidence of the erosive force of moving water; this turbulent stream has cut a deep, rugged gorge through the Precambrian volcanic bedrock, producing waterfalls, whirlpools and polished rock formations. Just shy of the Canadian border, Grand Portage State Park, stretching along the Pigeon River, provides access to Pigeon River Falls, the highest waterfall in Minnesota (120 feet). Finally, a scenic rest-stop, a few miles north of the town of Grand Portage, offers an awe-inspiring view of Lake Superior, its coastal hills, the offshore Susie Islands and the distant silhouette of Isle Royale, stretching across the northeastern horizon.
While towns, marinas, resorts and industrial ports are also spaced along Superior's Northwest Coast, they do not begin to detract from its fabulous natural landscape and the abundance of State Parks, State Forests and dedicated Wilderness could keep any naturalist entertained for months, if not years. Our only regret is that we had too little time to explore that scenic wonderland.
A few of these Parks deserve special mention. Gooseberry River State Park, a few miles north of Two Harbors, is accessed by an excellent network of trails that lead past a series of beautiful waterfalls, lead out to cliff-top views of the lake and river valley or take the visitor down to the rocky shore. Temperance River State Park, just north of Taconic Harbor, provides spectacular evidence of the erosive force of moving water; this turbulent stream has cut a deep, rugged gorge through the Precambrian volcanic bedrock, producing waterfalls, whirlpools and polished rock formations. Just shy of the Canadian border, Grand Portage State Park, stretching along the Pigeon River, provides access to Pigeon River Falls, the highest waterfall in Minnesota (120 feet). Finally, a scenic rest-stop, a few miles north of the town of Grand Portage, offers an awe-inspiring view of Lake Superior, its coastal hills, the offshore Susie Islands and the distant silhouette of Isle Royale, stretching across the northeastern horizon.
While towns, marinas, resorts and industrial ports are also spaced along Superior's Northwest Coast, they do not begin to detract from its fabulous natural landscape and the abundance of State Parks, State Forests and dedicated Wilderness could keep any naturalist entertained for months, if not years. Our only regret is that we had too little time to explore that scenic wonderland.
Selasa, 15 Mei 2012
Western Lake Superior
Facing an off-week and yearning to get back to the North Country after our memorable journey across the Upper Peninsula of Michigan, last September, my wife and I decided to head for western Lake Superior. We left Columbia yesterday afternoon, driving north across the Glaciated Plain of northern Missouri and eastern Iowa, stopping for the night in Iowa City. This morning, we resumed our journey, dropping into the Mississippi Valley at Marquette, Iowa, and then paralleling the broad river and its wooded islands along the Wisconsin (eastern) shore. Scenic bluffs rise along both sides of the Mississippi Valley in this "Driftless Area" of the Upper Midwest, which was spared the erosive force of Pleistocene Glaciers.
Protected within the Upper Mississippi National Wildlife Refuge, access to the Mississippi and its varied riparian habitats is rather limited (except for boaters). However, Goose Island County Park, just south of La Crosse, Wisconsin, provided an excellent opportunity to study the floodplain wetlands, backwater bays and eastern channel of the river; birding was excellent at the Park. North of La Crosse, we cut away from the Mississippi for a more direct route to Duluth, Minnesota, where we are spending the night on that city's restored waterfront.
In the coming days, we plan to explore the northwest coast of Lake Superior and the Apostle Islands region of northern Wisconsin. So far, wildlife encounters have been limited to bald eagles, sandhill cranes, common loons, gulls, aquatic turtles and a host of waterfowl and songbird species. But we are now in wolf and moose country and I look forward to the possibility of seeing (or hearing) those North Country residents amidst the spectacular landscape that adjoins America's grandest Lake.
Protected within the Upper Mississippi National Wildlife Refuge, access to the Mississippi and its varied riparian habitats is rather limited (except for boaters). However, Goose Island County Park, just south of La Crosse, Wisconsin, provided an excellent opportunity to study the floodplain wetlands, backwater bays and eastern channel of the river; birding was excellent at the Park. North of La Crosse, we cut away from the Mississippi for a more direct route to Duluth, Minnesota, where we are spending the night on that city's restored waterfront.
In the coming days, we plan to explore the northwest coast of Lake Superior and the Apostle Islands region of northern Wisconsin. So far, wildlife encounters have been limited to bald eagles, sandhill cranes, common loons, gulls, aquatic turtles and a host of waterfowl and songbird species. But we are now in wolf and moose country and I look forward to the possibility of seeing (or hearing) those North Country residents amidst the spectacular landscape that adjoins America's grandest Lake.
Sabtu, 25 Februari 2012
Eastern Sandhill Cranes
Most American birdwatchers associate sandhill cranes with the Great Plains and Western U.S., having seen large flocks at staging areas, such as the Platte River in Nebraska or the San Luis Valley in Colorado, or at wintering grounds in California, New Mexico or Texas. But there is a large and growing eastern population of sandhill cranes, composed primarily of the greater sandhill crane subspecies.
These cranes breed in the vicinity of James Bay, Canada and around the Great Lakes, from Minnesota and Wisconsin to Michigan and northern Ohio. On their migrations to wintering areas from southern Georgia to central Florida, they use two primary staging areas: the Jasper-Pulaski State Fish & Wildlife Area, in northwest Indiana, and the Hiwassee Wildlife Refuge, just NNE of Chattanooga, Tennessee. Of course, migrant flocks may be seen in wetland areas and agricultural fields anywhere between their breeding and wintering areas and the cranes may shorten their travels if mild conditions persist and they encounter a plentiful food supply.
Non-migratory populations include the Florida sandhill cranes, found from the Okefenokee Swamp to the Everglades (with the greatest number on the Kissimmee Prairie, north of Lake Okeechobee) and the endangered Mississippi sandhill cranes, found on or near the Mississippi Sandhill Crane NWR, along I-10 in southern Mississippi; the latter population currently numbers about 110 cranes. Another non-migratory population of sandhill cranes inhabits Cuba. All sandhill cranes, whether found in the eastern or western U.S., are threatened primarily by habitat loss, the result of marsh drainage, stream water diversion or agricultural development.
These cranes breed in the vicinity of James Bay, Canada and around the Great Lakes, from Minnesota and Wisconsin to Michigan and northern Ohio. On their migrations to wintering areas from southern Georgia to central Florida, they use two primary staging areas: the Jasper-Pulaski State Fish & Wildlife Area, in northwest Indiana, and the Hiwassee Wildlife Refuge, just NNE of Chattanooga, Tennessee. Of course, migrant flocks may be seen in wetland areas and agricultural fields anywhere between their breeding and wintering areas and the cranes may shorten their travels if mild conditions persist and they encounter a plentiful food supply.
Non-migratory populations include the Florida sandhill cranes, found from the Okefenokee Swamp to the Everglades (with the greatest number on the Kissimmee Prairie, north of Lake Okeechobee) and the endangered Mississippi sandhill cranes, found on or near the Mississippi Sandhill Crane NWR, along I-10 in southern Mississippi; the latter population currently numbers about 110 cranes. Another non-migratory population of sandhill cranes inhabits Cuba. All sandhill cranes, whether found in the eastern or western U.S., are threatened primarily by habitat loss, the result of marsh drainage, stream water diversion or agricultural development.
Sabtu, 01 Oktober 2011
Thoughts on Lake Superior
True to its name, Lake Superior is a landscape of superlatives. Bounded by 3000 miles of shoreline, it is the largest freshwater lake (by surface area) on the planet; indeed, Lake Superior is roughly the size of Maine. While its volume is less than that of Lake Baikal, in Siberia, it holds more water than all of our other Great Lakes combined.
We humans, with our anthropomorphic tendencies, often view Lake Superior as a magnificent yet powerful beast, prone to punishing gales; in reality, it is a complex aquatic ecosystem, enclosed within a glacial basin of ancient rock. While the lake has significant effects on the climate of the lands that surround it, Superior's harsh weather is primarily a reflection of its latitude and longitude; were it in the southern U.S., its reputation would be entirely different. In addition, the character of Lake Superior varies with location, a reflection of prevailing winds, feeder streams and its underwater topography, and its shoreline encompasses a wide range of habitats, including dunes, rocky beaches, cliffs, wetlands and mountainous terrain.
To know Lake Superior is to understand its complex web of life, its geophysical anatomy, its geographic relationships and its susceptibility to the effects of human communities that line its basin; this, of course, would take a lifetime. Having traveled along its southern coast over the past two weeks, I have gained a better appreciation for the spectacular diversity of this vast and beautiful landscape.
We humans, with our anthropomorphic tendencies, often view Lake Superior as a magnificent yet powerful beast, prone to punishing gales; in reality, it is a complex aquatic ecosystem, enclosed within a glacial basin of ancient rock. While the lake has significant effects on the climate of the lands that surround it, Superior's harsh weather is primarily a reflection of its latitude and longitude; were it in the southern U.S., its reputation would be entirely different. In addition, the character of Lake Superior varies with location, a reflection of prevailing winds, feeder streams and its underwater topography, and its shoreline encompasses a wide range of habitats, including dunes, rocky beaches, cliffs, wetlands and mountainous terrain.
To know Lake Superior is to understand its complex web of life, its geophysical anatomy, its geographic relationships and its susceptibility to the effects of human communities that line its basin; this, of course, would take a lifetime. Having traveled along its southern coast over the past two weeks, I have gained a better appreciation for the spectacular diversity of this vast and beautiful landscape.
Rabu, 28 September 2011
Elk in Michigan
North American wapiti, more commonly known as elk, are generally associated with mountainous regions of the West. However, before white settlers arrived with their guns, axes and plows, these large herbivores inhabited much of the Continent. Nevertheless, I was surprised to see "Elk Crossing" signs in the northern part of Michigan's Lower Peninsula during our recent visit and have since learned that this is the largest free roaming elk herd east of the Mississippi.
Elk were extirpated from Michigan by the late 1800s due to a combination of over-hunting and habitat loss. Then, during the second decade of the 20th Century, efforts were made to re-establish an elk population in the Pigeon River watershed of the northeast Lower Peninsula; despite some initial success, poaching and the degradation of habitat proved to be significant problems. Finally, through the cooperation of landowners, the general public and the Department of Natural Resources, the Michigan elk population began to stabilize in the 1970s and has recently been maintained between 800-900 wintering individuals; habitat restoration and a strictly controlled hunting program have been instrumental in this effort.
While the reintroduction of a native species is, in general, a laudable project, it cannot be successful without both adequate habitat protection and a reliable means of population control. Since the State has no plans to reintroduce gray wolves and cougars in this region, population control falls to human hunters. Indeed, one wonders whether hunting and tourism proponents were the driving force behind this elk reintroduction program. The public surely enjoys the opportunity to observe these magnificent animals in the wild but, for all practical purposes, the State of Michigan has created a regional hunting preserve.
Elk were extirpated from Michigan by the late 1800s due to a combination of over-hunting and habitat loss. Then, during the second decade of the 20th Century, efforts were made to re-establish an elk population in the Pigeon River watershed of the northeast Lower Peninsula; despite some initial success, poaching and the degradation of habitat proved to be significant problems. Finally, through the cooperation of landowners, the general public and the Department of Natural Resources, the Michigan elk population began to stabilize in the 1970s and has recently been maintained between 800-900 wintering individuals; habitat restoration and a strictly controlled hunting program have been instrumental in this effort.
While the reintroduction of a native species is, in general, a laudable project, it cannot be successful without both adequate habitat protection and a reliable means of population control. Since the State has no plans to reintroduce gray wolves and cougars in this region, population control falls to human hunters. Indeed, one wonders whether hunting and tourism proponents were the driving force behind this elk reintroduction program. The public surely enjoys the opportunity to observe these magnificent animals in the wild but, for all practical purposes, the State of Michigan has created a regional hunting preserve.
Selasa, 27 September 2011
Falling Water
As we left the cabin this morning, on our final day in Michigan's Upper Peninsula, a light rain was falling. The Porcupine Mountains were shrouded in fog as we headed west on the Park's South Boundary Road. We stopped to take a short loop hike in the morning mist, trudging along muddy paths and weaving through the soggy vegetation; two small but scenic waterfalls, Overlooked Falls and Greenstone Falls, rewarded our perseverance.
In the westernmost section of the Park, we hiked along the magnificent Presque Isle River, stopping to view its three major waterfalls and a cluster of rock-walled potholes, scoured out by the relentless river and its cargo of abrasive sand. From there we headed further west to the Black River Valley, in the Ottawa National Forest, where a family of five bald eagles endured the chilly drizzle in the top of a dead pine; another group of spectacular cascades were spaced along this stream and a beautiful crescent beach stretched northward along Lake Superior from the Black River Harbor.
Despite the gray, damp weather, it was another enjoyable day in this land of water and rock. Heading toward Iron Mountain on Route 2, we traversed a final assault of heavy rain before the clouds pushed to our south and brilliant sunshine ignited the painted autumn forests of the Upper Peninsula. Tomorrow we'll head for Madison, Wisconsin, my wife's college hangout.
In the westernmost section of the Park, we hiked along the magnificent Presque Isle River, stopping to view its three major waterfalls and a cluster of rock-walled potholes, scoured out by the relentless river and its cargo of abrasive sand. From there we headed further west to the Black River Valley, in the Ottawa National Forest, where a family of five bald eagles endured the chilly drizzle in the top of a dead pine; another group of spectacular cascades were spaced along this stream and a beautiful crescent beach stretched northward along Lake Superior from the Black River Harbor.
Despite the gray, damp weather, it was another enjoyable day in this land of water and rock. Heading toward Iron Mountain on Route 2, we traversed a final assault of heavy rain before the clouds pushed to our south and brilliant sunshine ignited the painted autumn forests of the Upper Peninsula. Tomorrow we'll head for Madison, Wisconsin, my wife's college hangout.
Senin, 26 September 2011
The Precambrian Peninsula
The western third of Michigan's Upper Peninsula, including the Keweenaw Peninsula, does not lie within the Michigan Basin. Rather, from a geophysical point of view, it is part of the Wisconsin Dome, which also includes much of northern Wisconsin and northeast Minnesota; in this region, which blends with the Canadian Shield, Precambrian rocks outcrop at the surface since overlying, younger sediments were either scraped away by the Pleistocene glaciers or eroded away in the distant past due to the general uplift of these ancient basement rocks.
We decided to give our legs a rest today and took a road trip to Copper Harbor, stopping at various lighthouses and beaches along the way. The highlight of the trip was the view from Brockway Mountain, just outside Copper Harbor; from this summit, one enjoys a panorama of Lake Superior and the northern Keweenaw Peninsula, including the shipping lanes, the rocky shoreline, inland lakes and colorful, forested ridges. Wherever we stopped, outcrops of Precambrian rock, volcanic or continental, dominated the scene; along portions of the coast, hogbacks and shoals of ancient basalt created a fascinating and scenic topography.
As I discussed yesterday, the Porcupine Mountains are volcanic in origin, as are some other ridges and uplifts across the Wisconsin Dome. Other ranges, such as the Huron Mountains east of Keweenaw Bay, have eroded from localized Precambrian domes (similar to the formation of the Black Hills and Adirondacks). Of course, the highlands across the Wisconsin Dome are among the oldest in North America (1-3 billion years old) and, over time, have eroded into hills and relatively low ridges. Just knowing you are walking on or amidst rock that pre-dates terrestrial life is an exhilarating experience.
We decided to give our legs a rest today and took a road trip to Copper Harbor, stopping at various lighthouses and beaches along the way. The highlight of the trip was the view from Brockway Mountain, just outside Copper Harbor; from this summit, one enjoys a panorama of Lake Superior and the northern Keweenaw Peninsula, including the shipping lanes, the rocky shoreline, inland lakes and colorful, forested ridges. Wherever we stopped, outcrops of Precambrian rock, volcanic or continental, dominated the scene; along portions of the coast, hogbacks and shoals of ancient basalt created a fascinating and scenic topography.
As I discussed yesterday, the Porcupine Mountains are volcanic in origin, as are some other ridges and uplifts across the Wisconsin Dome. Other ranges, such as the Huron Mountains east of Keweenaw Bay, have eroded from localized Precambrian domes (similar to the formation of the Black Hills and Adirondacks). Of course, the highlands across the Wisconsin Dome are among the oldest in North America (1-3 billion years old) and, over time, have eroded into hills and relatively low ridges. Just knowing you are walking on or amidst rock that pre-dates terrestrial life is an exhilarating experience.
Minggu, 25 September 2011
The Porcupine Mountains
About twenty miles west of the Keweenaw Peninsula, the Porcupine Mountains rise above the south shore of Lake Superior. Volcanic in origin, the "Porkies" formed 1 billion years ago along the Mid-Continent Rift; long quiescent, this rift extends southwestward into the Central Plains of the U.S. where, since buried by younger sediments, it remains a potential source for deep earthquakes.
Since their Precambrian birth, the Porcupine Mountains have been assaulted by the forces of erosion, especially during the Pleistocene Epoch when glaciers scoured the region. Today, an escarpment, capped by volcanic basalt, curves along the northern edge of the Porcupines, separated from the main uplift by the Big Carp Valley and its beautiful Lake of the Clouds; hikes along the escarpment are among the most scenic in the Park. Another popular hike is a short but steady climb to the top of Summit Mountain, 1958 feet (the highest point in the Porcupines), where a lookout tower offers a magnificent panorama of the Park and its surroundings, extending to Lake Superior; on a clear day, one can see the Apostle Islands (to the northwest) and Isle Royale, 80 miles to the north.
While the Porcupine Mountains formed 600 million years before life crawled from the sea, they now host a spectacular diversity of plant and animal residents. Among these are black bear, gray wolves, fishers and, of course, porcupines; so far, our mammal encounters have been limited to deer, squirrels, chipmunks and other humans. A Visitor Center, at the east entrance to this Michigan State Park, provides an excellent introduction to the region's natural and human history and access to this scenic refuge is provided by a well-engineered network of trails and boardwalks. Visitors should be aware that a Park passport fee is charged.
Since their Precambrian birth, the Porcupine Mountains have been assaulted by the forces of erosion, especially during the Pleistocene Epoch when glaciers scoured the region. Today, an escarpment, capped by volcanic basalt, curves along the northern edge of the Porcupines, separated from the main uplift by the Big Carp Valley and its beautiful Lake of the Clouds; hikes along the escarpment are among the most scenic in the Park. Another popular hike is a short but steady climb to the top of Summit Mountain, 1958 feet (the highest point in the Porcupines), where a lookout tower offers a magnificent panorama of the Park and its surroundings, extending to Lake Superior; on a clear day, one can see the Apostle Islands (to the northwest) and Isle Royale, 80 miles to the north.
While the Porcupine Mountains formed 600 million years before life crawled from the sea, they now host a spectacular diversity of plant and animal residents. Among these are black bear, gray wolves, fishers and, of course, porcupines; so far, our mammal encounters have been limited to deer, squirrels, chipmunks and other humans. A Visitor Center, at the east entrance to this Michigan State Park, provides an excellent introduction to the region's natural and human history and access to this scenic refuge is provided by a well-engineered network of trails and boardwalks. Visitors should be aware that a Park passport fee is charged.
Jumat, 23 September 2011
Pictured Rocks
The Pictured Rocks, which tower above Lake Superior east of Munising, are likely the most photographed natural feature of the Upper Peninsula of Michigan. These scenic cliffs anchor the west end of the Pictured Rocks National Lakeshore, which extends eastward to Grand Marias. Composed of Cambrian sandstone, deposited in a broad river delta about 550 million years ago, these rocks lie in the outermost band of the Michigan Basin and are some 400 million years older than the Jurassic sediments at the Basin's center.
This morning, my wife and I took a boat tour along the base of the Pictured Rocks; conducted by a private company in cooperation with the National Park Service, the tour provided a unique and up-close view of the spectacular cliffs that were exposed by Pleistocene glaciers and are now molded by the erosive forces of Lake Superior and the region's harsh northern climate. Rock falls are a common occurrence along this majestic wall, producing recessed caves, natural arches and varied rock formations that evoke images in the eyes of human visitors (hence the name of Pictured Rocks). The boat officers and an onboard Park ranger introduced us to both the natural and the human history of this region, including the story behind many of the shipwrecks that have occurred along this storm-ridden coast.
Later in the day, we hiked out to Chapel Rock, where a pine tree grows from the top of a rock pedestal, its roots dangling between the pedestal cap and the adjacent cliff; those roots formerly ran through the soil of a rock arch before the latter collapsed into the lake. On our loop hike to and from this popular site we passed through a karst landscape which included Chapel Falls and numerous sinkholes; this topography reflects the layer of Ordovician dolomite that overlies the Permian sandstone south and east of Pictured Rocks (i.e. toward the center of the Michigan Basin). Tomorrow, we'll head westward to the Keweenaw Peninsula and thence to the Porcupine Mountains.
This morning, my wife and I took a boat tour along the base of the Pictured Rocks; conducted by a private company in cooperation with the National Park Service, the tour provided a unique and up-close view of the spectacular cliffs that were exposed by Pleistocene glaciers and are now molded by the erosive forces of Lake Superior and the region's harsh northern climate. Rock falls are a common occurrence along this majestic wall, producing recessed caves, natural arches and varied rock formations that evoke images in the eyes of human visitors (hence the name of Pictured Rocks). The boat officers and an onboard Park ranger introduced us to both the natural and the human history of this region, including the story behind many of the shipwrecks that have occurred along this storm-ridden coast.
Later in the day, we hiked out to Chapel Rock, where a pine tree grows from the top of a rock pedestal, its roots dangling between the pedestal cap and the adjacent cliff; those roots formerly ran through the soil of a rock arch before the latter collapsed into the lake. On our loop hike to and from this popular site we passed through a karst landscape which included Chapel Falls and numerous sinkholes; this topography reflects the layer of Ordovician dolomite that overlies the Permian sandstone south and east of Pictured Rocks (i.e. toward the center of the Michigan Basin). Tomorrow, we'll head westward to the Keweenaw Peninsula and thence to the Porcupine Mountains.
Kamis, 22 September 2011
South of Superior
When we arrived at Whitefish Point this morning, a raw, northwest wind raised whitecaps on Lake Superior where an ore ship, similar to the Edmund Fitzgerald, was closing in on Whitefish Bay; backed by the rugged cliffs of the Ontario coast, the freighter was headed for the locks at Sault Ste. Marie. Noisy gulls cavorted in the cold, steady breeze, a flock of horned larks scurried across the barren, pebble-strewn beach and, out on the calmer bay, a lone red-throated grebe and a trio of common loons dove for their breakfast.
Once back in our warm car, we headed west, crossing the wooded bogs of Michigan's moose country. Along the way, we took side trips to the Lower and Upper Falls of the beautiful Tahquamenon River, where its pristine waters tumble over shelves of early Paleozoic sandstone and dolomite. Further west, we returned to the southern shore of Lake Superior, entering the Pictured Rocks National Lakeshore at Grand Marias; hikes to Sable Falls, the Grand Sable Dunes and the Au Sable Lighthouse rounded out our day. After a night in Munising, we'll return to the Pictured Rocks coast tomorrow morning.
It was fitting to end our day at the Au Sable Lighthouse, which commands a spectacular view of Lake Superior. Built in 1910 and restored during the past decade, the light is both a beacon of hope amidst the harsh conditions of this northern coast and a silent memorial to the many lives lost in the turbulent waters of this magnificent lake.
Once back in our warm car, we headed west, crossing the wooded bogs of Michigan's moose country. Along the way, we took side trips to the Lower and Upper Falls of the beautiful Tahquamenon River, where its pristine waters tumble over shelves of early Paleozoic sandstone and dolomite. Further west, we returned to the southern shore of Lake Superior, entering the Pictured Rocks National Lakeshore at Grand Marias; hikes to Sable Falls, the Grand Sable Dunes and the Au Sable Lighthouse rounded out our day. After a night in Munising, we'll return to the Pictured Rocks coast tomorrow morning.
It was fitting to end our day at the Au Sable Lighthouse, which commands a spectacular view of Lake Superior. Built in 1910 and restored during the past decade, the light is both a beacon of hope amidst the harsh conditions of this northern coast and a silent memorial to the many lives lost in the turbulent waters of this magnificent lake.
Rabu, 21 September 2011
Mackinac Island
Mackinac Island is an erosional remnant, carved from Devonian limestone by the forces of ice, wind and water. It sits in the Mackinac Strait, between Lakes Michigan and Huron, and is accessed by a twenty minute boat ride from the mainland; since no motorized vehicles are allowed on the island, all land transportation is by foot, bicycle or horse power.
Like all tourist resorts, Mackinac Island has its share of luxury hotels, brew-pubs, T-shirt shops and fudge kitchens. But most of the action and secondary tourist congestion is limited to the main downtown area and those with the energy and interest to bike or walk to other parts of the island are rewarded with broad shoreline vistas, woodland trails, peaceful lanes and a host of historic sites, including an 18th Century British Fort. Wave action and stream erosion along the coast has also produced a number of rock formations, including the famous Arch Rock.
Though it is a cloudy, damp day in northern Michigan, we enjoyed an 8.5 mile bike ride around the edge of the Island, taking in views of the Mackinac Bridge, Lake Huron and of the Island's scenic coast; among the birdlife were ring-billed and herring gulls, Canada geese, cormorants, red-breasted mergansers, a few common loons and an apparent flock of scoters, too distant to identify. Once the rain stops, we plan another journey through the center of Mackinac Island; by mid morning, we'll return to the mainland and head for the Upper Peninsula.
Like all tourist resorts, Mackinac Island has its share of luxury hotels, brew-pubs, T-shirt shops and fudge kitchens. But most of the action and secondary tourist congestion is limited to the main downtown area and those with the energy and interest to bike or walk to other parts of the island are rewarded with broad shoreline vistas, woodland trails, peaceful lanes and a host of historic sites, including an 18th Century British Fort. Wave action and stream erosion along the coast has also produced a number of rock formations, including the famous Arch Rock.
Though it is a cloudy, damp day in northern Michigan, we enjoyed an 8.5 mile bike ride around the edge of the Island, taking in views of the Mackinac Bridge, Lake Huron and of the Island's scenic coast; among the birdlife were ring-billed and herring gulls, Canada geese, cormorants, red-breasted mergansers, a few common loons and an apparent flock of scoters, too distant to identify. Once the rain stops, we plan another journey through the center of Mackinac Island; by mid morning, we'll return to the mainland and head for the Upper Peninsula.
Selasa, 20 September 2011
Sleeping Bear Dunes
Stretching along the northwest coast of Michigan's lower peninsula, massive sand dunes rise above Lake Michigan. Protected as a National Lakeshore since 1970, these dunes attest to both the erosive force of the Pleistocene glaciers and the powerful storms that have regularly lashed the region since those ice sheets retreated. While lakeshore "beach dunes" are modest in size, those atop the cliffs, known as "perched dunes" and composed of glacial sand, tower up to 450 feet above the waters of Lake Michigan and encompass a broad swath of shifting landscape. Bordered by a rich beech-maple forest, the dunes are temporarily stabilized by beach grasses, wildflowers, sand-tolerant shrubs and groves of cottonwood but, over time, are sculpted and advanced by the relentless wind, swallowing tracts of forest that lie in their path.
A Visitor Center, located in Empire, offers an introduction to the natural history of this fascinating ecosystem and provides an overview of the plants and animals that inhabit the dunes and adjacent forest. In addition, an auto tour road provides access to a host of overlooks, several of which yield spectacular views of the dunes, Lake Michigan and offshore islands. Those with the time and ability to do so are encouraged to hike at least one of the trails that lead into this beautiful yet harsh environment; trudging through the sand, especially when accompanied by intense sunshine and a strong wind, makes one appreciate the true nature of this unforgiving landscape.
Sleeping Bear Dunes National Lakeshore is located about 28 miles west of Traverse City, Michigan and is best reached via Michigan Highway 72. Its name is derived from a prominent dune that, topped by a clump of shrubs, resembled a sleeping bear in the eyes of Native American residents. While modern visitors might not appreciate that visual interpretation, they are sure to agree that this scenic coastline is one of the most spectacular sites in North America.
A Visitor Center, located in Empire, offers an introduction to the natural history of this fascinating ecosystem and provides an overview of the plants and animals that inhabit the dunes and adjacent forest. In addition, an auto tour road provides access to a host of overlooks, several of which yield spectacular views of the dunes, Lake Michigan and offshore islands. Those with the time and ability to do so are encouraged to hike at least one of the trails that lead into this beautiful yet harsh environment; trudging through the sand, especially when accompanied by intense sunshine and a strong wind, makes one appreciate the true nature of this unforgiving landscape.
Sleeping Bear Dunes National Lakeshore is located about 28 miles west of Traverse City, Michigan and is best reached via Michigan Highway 72. Its name is derived from a prominent dune that, topped by a clump of shrubs, resembled a sleeping bear in the eyes of Native American residents. While modern visitors might not appreciate that visual interpretation, they are sure to agree that this scenic coastline is one of the most spectacular sites in North America.
Senin, 19 September 2011
North by Northeast
It was a mild but overcast day as we drove northeast across the till plains of the American Midwest. Despite the low clouds, intermittent fog and pockets of drizzle, the golden hues of late summer adorned the landscape and brightened our journey.
We entered the Michigan Basin in northern Illinois, where the Kankakee Arch, a deeply buried ridge of ancient, Precambrian rock, divides the Michigan Basin, to its northeast, from the Illinois Basin, to its southwest. Of course, the Pleistocene ice sheets flattened this region and buried the underlying bedrock with a thick layer of glacial till; as a result, there is no surface topography that reflects the deep divide and surface streams cross freely from one geologic basin to the other.
In southwest Michigan, we traveled northward, paralleling the shore of Lake Michigan and passing inland dunes, remnants of the Lake's larger, post-glacial predecessor. Past Holland, we turned eastward to Grand Rapids and then continued northward, entering the scenic, wooded hills that cover the heart of the Michigan Basin; with every mile, the colors of autumn became more intense and the percentage of conifers, relative to their colorful, broadleaf neighbors, continued to increase. Finally, having booked a hotel room in Traverse City, we took an evening stroll along West Traverse Bay, a welcome bit of exercise after a ten hour drive. Tomorrow, we plan a morning visit to Sleeping Bear Dunes and then we're off to Mackinac Island.
We entered the Michigan Basin in northern Illinois, where the Kankakee Arch, a deeply buried ridge of ancient, Precambrian rock, divides the Michigan Basin, to its northeast, from the Illinois Basin, to its southwest. Of course, the Pleistocene ice sheets flattened this region and buried the underlying bedrock with a thick layer of glacial till; as a result, there is no surface topography that reflects the deep divide and surface streams cross freely from one geologic basin to the other.
In southwest Michigan, we traveled northward, paralleling the shore of Lake Michigan and passing inland dunes, remnants of the Lake's larger, post-glacial predecessor. Past Holland, we turned eastward to Grand Rapids and then continued northward, entering the scenic, wooded hills that cover the heart of the Michigan Basin; with every mile, the colors of autumn became more intense and the percentage of conifers, relative to their colorful, broadleaf neighbors, continued to increase. Finally, having booked a hotel room in Traverse City, we took an evening stroll along West Traverse Bay, a welcome bit of exercise after a ten hour drive. Tomorrow, we plan a morning visit to Sleeping Bear Dunes and then we're off to Mackinac Island.
Sabtu, 17 September 2011
The Michigan Basin
If we could scrape away the Paleozoic, Mesozoic and Cenozoic deposits from the Continents, we would find that the ancient, Precambrian basement rock has a topography of ridges, valleys, plains and basins, similar to what we find on our planet's surface today. One of the basins, centered on the lower peninsula of Michigan, stretches from western New York to eastern Wisconsin and from Ontario, Canada to northern Ohio and Indiana.
Known as the Michigan Basin, this broad bowl has gradually filled with sedimentary rocks from the Paleozoic and Mesozoic Eras; as one might expect, sediments advance in age from top to bottom and, on the surface, from the center of the basin to the periphery. The youngest of these deposits, Jurassic in age, are found in the west-central region of lower Michigan while the oldest surface in Ontario (on the north edge of Lake Huron), across the Upper Peninsula of Michigan, along the eastern side of Wisconsin, in Greater Chicago and in the vicinity of Niagara Falls. Most of the basin sediments have since been covered by a thick layer of Pleistocene glacial till and, of course, by the waters of Lakes Superior, Michigan, Huron and Erie.
Over the next two weeks, my wife and I plan to circle across the Michigan Basin, spending two days on Mackinac Island and most of our time along the Upper Peninsula of Michigan. Since I have been through that region in the past, I generally know what to expect but, like all journeys, the adventure lies in the unexpected. Reports from the Basin will follow.
Known as the Michigan Basin, this broad bowl has gradually filled with sedimentary rocks from the Paleozoic and Mesozoic Eras; as one might expect, sediments advance in age from top to bottom and, on the surface, from the center of the basin to the periphery. The youngest of these deposits, Jurassic in age, are found in the west-central region of lower Michigan while the oldest surface in Ontario (on the north edge of Lake Huron), across the Upper Peninsula of Michigan, along the eastern side of Wisconsin, in Greater Chicago and in the vicinity of Niagara Falls. Most of the basin sediments have since been covered by a thick layer of Pleistocene glacial till and, of course, by the waters of Lakes Superior, Michigan, Huron and Erie.
Over the next two weeks, my wife and I plan to circle across the Michigan Basin, spending two days on Mackinac Island and most of our time along the Upper Peninsula of Michigan. Since I have been through that region in the past, I generally know what to expect but, like all journeys, the adventure lies in the unexpected. Reports from the Basin will follow.
Jumat, 20 Mei 2011
Formation of the Great Lakes
Looking at a map of North America, one's attention is immediately drawn to the Great Lakes, the most conspicuous geographic feature of the Continent. Yet, carved by the Pleistocene glaciers, they are also among the youngest landforms on the surface of our planet.
The Precambrian basement of our continents, like the visible topography of Earth, is a composite of ridges, basins and plains. One of these basins, centered over Lower Michigan, encompasses the Great Lakes region, having filled in with Paleozoic, Mesozoic and Tertiary sediments. Over the course of this deposition, a major river system developed within the Michigan Basin, likely draining toward the Atlantic. During the Pleistocene, which began 2 million years ago, four major continental glaciers plowed across that basin, altering the landscape and widening the river valleys; the last of these glaciers, the Wisconsin, began to form just 70,000 years ago and reached its peak advance about 18,000 years ago. As it began to melt back into Canada, its surging waters filled the remodeled lake basins, which initially drained into the Mississippi watershed via the Illinois, Kankakee and Wabash Rivers. Relieved of the glacial weight, the Upper Midwest began to rebound and some of the drainge shifted eastward, through the Mohawk River Valley, until the St. Lawrence Seaway opened and the Great Lakes assumed their current shape and hydrology; it has only been during the last 4-6,000 years that this massive lake system, which holds almost 25% of the liquid fresh water on Earth, reached an apparent steady state.
Lake plains and inland dunes, most evident across northern Ohio and Indiana, attest to the larger size of the Lakes prior to opening of the St. Lawrence River. Even today, the drainage pattern continues to change as southern Canada rebounds from the weight of the ice; as the land north of the Lakes rises, many geologists and hydrologists believe that the primary drainage will shift back to the southwest, threatening urban centers along the lakeshores and river corridors. Then again, since the Holocene could be just another warm, interglacial period, the ice may return to reclaim the Lakes.
The Precambrian basement of our continents, like the visible topography of Earth, is a composite of ridges, basins and plains. One of these basins, centered over Lower Michigan, encompasses the Great Lakes region, having filled in with Paleozoic, Mesozoic and Tertiary sediments. Over the course of this deposition, a major river system developed within the Michigan Basin, likely draining toward the Atlantic. During the Pleistocene, which began 2 million years ago, four major continental glaciers plowed across that basin, altering the landscape and widening the river valleys; the last of these glaciers, the Wisconsin, began to form just 70,000 years ago and reached its peak advance about 18,000 years ago. As it began to melt back into Canada, its surging waters filled the remodeled lake basins, which initially drained into the Mississippi watershed via the Illinois, Kankakee and Wabash Rivers. Relieved of the glacial weight, the Upper Midwest began to rebound and some of the drainge shifted eastward, through the Mohawk River Valley, until the St. Lawrence Seaway opened and the Great Lakes assumed their current shape and hydrology; it has only been during the last 4-6,000 years that this massive lake system, which holds almost 25% of the liquid fresh water on Earth, reached an apparent steady state.
Lake plains and inland dunes, most evident across northern Ohio and Indiana, attest to the larger size of the Lakes prior to opening of the St. Lawrence River. Even today, the drainage pattern continues to change as southern Canada rebounds from the weight of the ice; as the land north of the Lakes rises, many geologists and hydrologists believe that the primary drainage will shift back to the southwest, threatening urban centers along the lakeshores and river corridors. Then again, since the Holocene could be just another warm, interglacial period, the ice may return to reclaim the Lakes.
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