Amateur geologists often assume that the continental and oceanic plates coincide with the observable physical geography. In fact, most of the tectonic plates harbor both land and sea areas, which are merely surface features on the thick, underlying plates. For example, there is no Atlantic Plate; rather, this ocean is opening along the mid Atlantic Ridge and the crust formed on either side becomes part of the bordering Continental plates (i.e. this ridge is a rift between the North American and Eurasian Plates and between the South American and African Plates).
Land associated with a particular Continent does not always lie on that Continental Plate. The North American Plate, for example, stretches from the middle of the North Atlantic to the Pacific Coast; however, its northwestern extension runs across the northern edge of the Pacific Ocean, taking in the Aleutians, the Bering Sea, the northern islands of Japan and the eastern portion of Siberia. On the other hand, Southern California lies on the Pacific Plate but will eventually join the North American Plate after a long journey to Alaska. India, part of Asia on the map, actually sits on its own plate and Australia's plate runs beneath most of the Indian Ocean, a swath of the Southern Ocean, the eastern islands of Indonesia and both the Coral and Tasman Seas.
Since most earthquakes and volcanoes are associated with friction, compression and subduction along plate margins, it is important to know where these margins are located. More often than not, they do not correspond with what we see on the map!
Sunday, July 13, 2008
The American Antelope
Pronghorns are common across the High Plains, from the western Dakotas to Mexico, and on sage grasslands of the Intermountain West. Natives of North America, they are the sole remaining species of a family that included up to 13 members during the Tertiary Period and Pleistocene Epoch. Most paleontologists believe that pronghorns are not directly related to Old World antelopes and some feel that they are more closely aligned with cattle, sheep and goats. Indeed, like bovids, they have a horn composed of a keratin sheath that overlies a bony core; however, unlike bovids, the pronghorn's sheath is branched (in males) and is shed each year.
Once numbering over 40 million individuals, the pronghorn population declined dramatically throughout the 1800s and early 1900s due to over hunting and the fencing of rangelands. Unable to leap over fences, many starved when they were prevented from migrating during periods of heavy snow. Pronghorns are otherwise well equipped to withstand the harsh winters that typify most of their range; though relatively slender animals, they have a dense undercoat and their outer hairs are hollow, providing superb insulation.
Male pronghorns are territorial from late spring through early fall and gather a harem of up to 20 females; younger males travel about in bachelor herds and occasionally challenge the breeding males, often to their own detriment. Breeding occurs in early autumn and females give birth (usually to twins) in early summer. The young are kept hidden for several weeks and, by then, are able to outrun coyotes, their primary predator; as adults, they will become one of the fastest mammals on Earth, able to reach speeds of 70 miles per hour. In winter, pronghorns congregate in large herds, feeding on the lee side of mesas and roaming about to find open forage.
Once numbering over 40 million individuals, the pronghorn population declined dramatically throughout the 1800s and early 1900s due to over hunting and the fencing of rangelands. Unable to leap over fences, many starved when they were prevented from migrating during periods of heavy snow. Pronghorns are otherwise well equipped to withstand the harsh winters that typify most of their range; though relatively slender animals, they have a dense undercoat and their outer hairs are hollow, providing superb insulation.
Male pronghorns are territorial from late spring through early fall and gather a harem of up to 20 females; younger males travel about in bachelor herds and occasionally challenge the breeding males, often to their own detriment. Breeding occurs in early autumn and females give birth (usually to twins) in early summer. The young are kept hidden for several weeks and, by then, are able to outrun coyotes, their primary predator; as adults, they will become one of the fastest mammals on Earth, able to reach speeds of 70 miles per hour. In winter, pronghorns congregate in large herds, feeding on the lee side of mesas and roaming about to find open forage.
Saturday, July 12, 2008
Visual Pollution
As the political season gets underway, candidate signs are popping up all over Columbia. Some lawns host four or five candidates while others have several signs for the same individual. Large banners adorn the major intersections and smaller signs are affixed to cars and phone poles. Well-financed candidates smile down from interstate billboards and even scenic, country barns are plastered with names and slogans. To imagine that this visual pollution actually translates into votes is truly disturbing.
Then there's the permanent gauntlet of billboards along I-70. For a State with as much natural beauty as Missouri, the Government seems to be oblivious to these hideous displays. While other States are having them removed, Missouri condones new, monstrous structures that highlight the ads. Given that a significant percentage are rented by Adult Video stores, visitors and travellers may easily misinterpret the State's "Show-Me" nickname.
Conservation efforts should be directed at landscape as well as at habitat, species and natural resources. Though I vote in Colorado, I would gladly campaign for someone who wants to eliminate billboards and political signs in Missouri!
Then there's the permanent gauntlet of billboards along I-70. For a State with as much natural beauty as Missouri, the Government seems to be oblivious to these hideous displays. While other States are having them removed, Missouri condones new, monstrous structures that highlight the ads. Given that a significant percentage are rented by Adult Video stores, visitors and travellers may easily misinterpret the State's "Show-Me" nickname.
Conservation efforts should be directed at landscape as well as at habitat, species and natural resources. Though I vote in Colorado, I would gladly campaign for someone who wants to eliminate billboards and political signs in Missouri!
Friday, July 11, 2008
Man and his Animals
Humans have been capturing, breeding and using other animal species since the end of the Pleistocene. Dogs were the first to be domesticated, used for protection and hunting in the Middle East about 12,000 years ago. Goats were raised in the Fertile Crescent 10,000 years ago, followed by pigs and sheep in Turkey-Syria a thousand years later. Cattle were domesticated from northern Africa to India 8000 years ago; cats entered households in Egypt and chickens were first raised in Southeast Asia about the same time.
The horse, so important to the advance of human culture, was first used by humans in central Asia about 6000 years ago, followed by donkeys and camels across northern Africa and the Middle East 500 years later. Ducks were bred in Southeast Asia 5000 years ago, tribes in the Andes domesticated guinea pigs 4500 years ago and turkeys were raised in Mexico by 100 AD.
Europeans domesticated honey bees about 500 AD and rabbits by 1500 AD. Of course, a host of other species have been housed and "trained" in zoos and circuses.
All of this domestication, while often vital to the development of human civilization, has been of benefit to man alone and, as we all know, many animals have endured suffering and abuse along the way. Only our pampered, modern pets, which are engineered and unnatural species, have shared in the benefits.
The horse, so important to the advance of human culture, was first used by humans in central Asia about 6000 years ago, followed by donkeys and camels across northern Africa and the Middle East 500 years later. Ducks were bred in Southeast Asia 5000 years ago, tribes in the Andes domesticated guinea pigs 4500 years ago and turkeys were raised in Mexico by 100 AD.
Europeans domesticated honey bees about 500 AD and rabbits by 1500 AD. Of course, a host of other species have been housed and "trained" in zoos and circuses.
All of this domestication, while often vital to the development of human civilization, has been of benefit to man alone and, as we all know, many animals have endured suffering and abuse along the way. Only our pampered, modern pets, which are engineered and unnatural species, have shared in the benefits.
Thursday, July 10, 2008
Red Rocks Park
Internationally famous for its outdoor, rock-walled amphitheater, Red Rocks Park stretches across the base of Mt. Morrison, just west of Denver. Monoliths of Pennylvanian sandstone (the Fountain Formation) rise above the foothill shrublands, creating a scenic landscape for hikers and naturalists. Just east of the Park, the Dakota Hogback, Cretaceous in age, harbors dinosaur footprints and additional trails.
Foothill grasslands, studded with yucca and juniper, and streamside thickets of Gambel oak and mountain mahogany surround the massive rock formations, attracting a superb variety of wildlife. Golden eagles, common ravens and red-tailed hawks often circle overhead as squadrons of cliff swallows and white-throated swifts swoop along the monoliths. Canyon and rock wrens, rock squirrels, Colorado chipmunks and rock pigeons inhabit the sandstone cliffs and a colorful mix of songbirds nest and feed in the adjacent thickets; among the latter are lazuli buntings, black-headed grosbeaks, rufous-sided and green-tailed towhees, Virginia's warblers, yellow warblers and yellow-breasted chats. Scrub jays, loggerhead shrikes and black-billed magpies noisily patrol the open shrublands, Say's phoebes flycatch from fence posts and herds of mule deer browse the rocky slopes, wary of coyotes and mountain lions that hunt across the foothills.
Red Rocks Park lies west of Colorado 86, between Morrison and I-70 (take Exit 259 from the interstate and head south). A network of roadways and foot trails provide access to this scenic refuge; plan an early morning, weekday visit to avoid crowds and to see an excellent variety of wildlife.
Foothill grasslands, studded with yucca and juniper, and streamside thickets of Gambel oak and mountain mahogany surround the massive rock formations, attracting a superb variety of wildlife. Golden eagles, common ravens and red-tailed hawks often circle overhead as squadrons of cliff swallows and white-throated swifts swoop along the monoliths. Canyon and rock wrens, rock squirrels, Colorado chipmunks and rock pigeons inhabit the sandstone cliffs and a colorful mix of songbirds nest and feed in the adjacent thickets; among the latter are lazuli buntings, black-headed grosbeaks, rufous-sided and green-tailed towhees, Virginia's warblers, yellow warblers and yellow-breasted chats. Scrub jays, loggerhead shrikes and black-billed magpies noisily patrol the open shrublands, Say's phoebes flycatch from fence posts and herds of mule deer browse the rocky slopes, wary of coyotes and mountain lions that hunt across the foothills.
Red Rocks Park lies west of Colorado 86, between Morrison and I-70 (take Exit 259 from the interstate and head south). A network of roadways and foot trails provide access to this scenic refuge; plan an early morning, weekday visit to avoid crowds and to see an excellent variety of wildlife.
Wednesday, July 9, 2008
The Shade Tree Bird
Northern orioles are common summer birds throughout much of the U.S. Not forest birds, they prefer wood margins and open woodlands with large shade trees and are thus common in older residential areas. Indeed, they once favored the stately American elms that lined our boulevards before elm blight all but eliminated those magnificent trees.
Formerly called Baltimore orioles in the Eastern U.S. and Midwest, this race is now known to interbreed with Bullock's oriole of the West and they have been classified as one species, the northern oriole. Colorful and melodious, these summer residents are known for the pendulous, sack-like nests that they weave from various plant materials; a single brood of 4-6 young are generally raised each summer and family groups may be seen at favored berry shrubs. Adults are otherwise usually found alone or in pairs, scouring trees for caterpillars and beetles.
As one might expect, the Bullock's race, a resident of drier landscapes, is best found in stands of cottonwood that line the rivers and large creeks of the Western U.S. Like their eastern counterpart, they feed on insects and fruit and are frequent visitors to chokecherry shrubs and mulberry trees. Northern orioles generally arrive in the U.S. by early May and depart for Central and South America in mid-late September.
Formerly called Baltimore orioles in the Eastern U.S. and Midwest, this race is now known to interbreed with Bullock's oriole of the West and they have been classified as one species, the northern oriole. Colorful and melodious, these summer residents are known for the pendulous, sack-like nests that they weave from various plant materials; a single brood of 4-6 young are generally raised each summer and family groups may be seen at favored berry shrubs. Adults are otherwise usually found alone or in pairs, scouring trees for caterpillars and beetles.
As one might expect, the Bullock's race, a resident of drier landscapes, is best found in stands of cottonwood that line the rivers and large creeks of the Western U.S. Like their eastern counterpart, they feed on insects and fruit and are frequent visitors to chokecherry shrubs and mulberry trees. Northern orioles generally arrive in the U.S. by early May and depart for Central and South America in mid-late September.
Tuesday, July 8, 2008
Gondwana and Marsupials
Throughout most of the Permian, Earth's land masses had merged into the mega-continent of Pangea. Then, in the Triassic (about 200 million years ago), the Tethys Sea began to form, rifting the northern Continents (Laurasia) from the southern Continents (Gondwana); the latter included South America, Africa, Antarctica and Australia. About 160 million years ago, the northern Atlantic started to open, dividing future North America from Eurasia, and Madagascar broke from Africa, drifting south to join the Antarctica-India land mass.
Marsupials arose in North America during the Cretaceous Period, some 100 million years ago; other mammals had become eutherians (placental mammals) and were beginning to colonize the northern Continents. Just before marsupials spread southward and eastward through Gondwana, the southern Atlantic split Africa from South America and Madagascar rifted from Antarctica, eventually docking off the coast of Africa. About 90 million years ago, India broke from Antarctica, heading toward its collision with southern Asia; South America drifted into isolation 75 million years ago and Australia followed suite 20 million years later.
Marsupials had spread through South America, Antarctica, India and Australia before these latter rifts developed. Those that remained in North America were rapidly displaced by eutherians and, when India merged with Asia, 60 million years ago, the same occurred in that region. South America's marsupials managed to hold on during its prolonged isolation but those in Antarctica succumbed to the climate as that Continent drifted to the South Pole; only those in Australia, free from the competition of eutherians, thrived and diversified. Finally, after Panama lodged between North and South America, some 3 million years ago, the Virginia opossum, our Continent's lone marsupial, spread back from the south.
Marsupials arose in North America during the Cretaceous Period, some 100 million years ago; other mammals had become eutherians (placental mammals) and were beginning to colonize the northern Continents. Just before marsupials spread southward and eastward through Gondwana, the southern Atlantic split Africa from South America and Madagascar rifted from Antarctica, eventually docking off the coast of Africa. About 90 million years ago, India broke from Antarctica, heading toward its collision with southern Asia; South America drifted into isolation 75 million years ago and Australia followed suite 20 million years later.
Marsupials had spread through South America, Antarctica, India and Australia before these latter rifts developed. Those that remained in North America were rapidly displaced by eutherians and, when India merged with Asia, 60 million years ago, the same occurred in that region. South America's marsupials managed to hold on during its prolonged isolation but those in Antarctica succumbed to the climate as that Continent drifted to the South Pole; only those in Australia, free from the competition of eutherians, thrived and diversified. Finally, after Panama lodged between North and South America, some 3 million years ago, the Virginia opossum, our Continent's lone marsupial, spread back from the south.
Monday, July 7, 2008
Recycling and Consumption
Many Americans take part in recycling programs. Every garbage day, they set out their basket of newspapers, soda cans and beer bottles. Yet, despite this important and well-intentioned effort, few take a broader approach to the problem of resource depletion.
Recycling recaptures component materials, reduces the energy needed to produce new items, cuts the space and energy needed for garbage disposal and reduces the destruction and utilization of natural resources. But the recycling step is only part of the solution; we must also be willing to choose products that are made with recycled materials, avoid items whose production threatens natural ecosystems and diminish overall consumption of new products.
Excessive consumption is the primary threat to our natural resources. The demand for new cars, new houses, new clothes and the latest gadgets all take a toll. Of course, this consumption is especially evident in affluent countries, of which the U.S. is king. That basket of recyclables is only a start; we must reduce our population growth and learn to live with less. Otherwise, we will consume our way to desolation.
Recycling recaptures component materials, reduces the energy needed to produce new items, cuts the space and energy needed for garbage disposal and reduces the destruction and utilization of natural resources. But the recycling step is only part of the solution; we must also be willing to choose products that are made with recycled materials, avoid items whose production threatens natural ecosystems and diminish overall consumption of new products.
Excessive consumption is the primary threat to our natural resources. The demand for new cars, new houses, new clothes and the latest gadgets all take a toll. Of course, this consumption is especially evident in affluent countries, of which the U.S. is king. That basket of recyclables is only a start; we must reduce our population growth and learn to live with less. Otherwise, we will consume our way to desolation.
Sunday, July 6, 2008
The Mammal Explosion
Though mammals first appeared in the Triassic, some 200 million years ago, they lived in the shadow of the dinosaurs and remained rather small and inconspicuous creatures. These therians split into eutherian (placental) and marsupial lines in the Cretaceous (100 million years ago) but did not diversify significantly until the demise of the dinosaurs, 65 million years ago.
Then, over the first two Epochs of the Tertiary (the Paleocene and Eocene), mammals exploded in number and variety. During this period (65 to 38 million years ago), primates, bats, the first ruminants and ancestral elephants appeared. Primates diverged into prosimians (future lemurs, lorises, galagos) and ancestral anthropods (future monkeys, apes, hominids) and, in North America, ancestral horses, rhinos and camels evolved. Canids (wolves, fox, dogs) and felines split from a common ancestor and the earliest cetaceans (whales, dolphins) returned to the sea.
While many of these ancestral species bore little resemblance to modern mammals, the stage was set for mammals to dominate earth's ecosystems. The Cenozoic Era (the Age of Mammals) began with this explosion and continues today. Most assume that humans, which finally graced the scene 125,000 years ago, are the culmination of this process; more likely, we are just another species in the web of mammal evolution.
Then, over the first two Epochs of the Tertiary (the Paleocene and Eocene), mammals exploded in number and variety. During this period (65 to 38 million years ago), primates, bats, the first ruminants and ancestral elephants appeared. Primates diverged into prosimians (future lemurs, lorises, galagos) and ancestral anthropods (future monkeys, apes, hominids) and, in North America, ancestral horses, rhinos and camels evolved. Canids (wolves, fox, dogs) and felines split from a common ancestor and the earliest cetaceans (whales, dolphins) returned to the sea.
While many of these ancestral species bore little resemblance to modern mammals, the stage was set for mammals to dominate earth's ecosystems. The Cenozoic Era (the Age of Mammals) began with this explosion and continues today. Most assume that humans, which finally graced the scene 125,000 years ago, are the culmination of this process; more likely, we are just another species in the web of mammal evolution.
Saturday, July 5, 2008
Volcanic Islands
While Greenland, Madagascar and Tasmania rifted away from other Continental land masses, the great majority of oceanic islands are volcanic in origin. Of these, most lie along subduction zones, where one of Earth's tectonic plates is subducting beneath another; in these areas, the crust of the subducted plate begins to melt as it approaches the mantle, producing a line of volcanoes on the overlying plate.
The Aleutians and northern islands of Japan have formed where the Pacific Plate is subducting beneath the North American Plate; in like manner, the archipelagos of Indonesia, southeast Asia (Taiwan, the Philippines, southern Japan) and the South Pacific (Solomon Islands, New Zealand) rise above subduction zones at the margins of the Pacific, Australian and Philippine Plates. The Lesser Antilles, stretching along the eastern edge of the Caribbean Sea, were produced by subduction of both the North and South American Plates beneath the Caribbean Plate.
Iceland, which rose from the sea 16 million years ago, has resulted from volcanism along the mid Atlantic Ridge (where the spreading Atlantic continues to rift North America from Eurasia); indeed, this island nation straddles the two Continental Plates. A third type of volcanic island, produced by a mantle plume, can develop far from any plate margin; the Hawaiian Island chain, the Galapagos Islands, the Azores and Easter Island are examples of such isolated "hotspot" volcanism.
Of course, all of these islands are prone to continued volcanic activity, even after hundreds or thousands of years of quiescence; only hotspot islands that have been transported away from the mantle plume (by movement of their oceanic plate) are immune to reawakening. Earth's landscape continues to evolve and humans are finally around to observe it!
The Aleutians and northern islands of Japan have formed where the Pacific Plate is subducting beneath the North American Plate; in like manner, the archipelagos of Indonesia, southeast Asia (Taiwan, the Philippines, southern Japan) and the South Pacific (Solomon Islands, New Zealand) rise above subduction zones at the margins of the Pacific, Australian and Philippine Plates. The Lesser Antilles, stretching along the eastern edge of the Caribbean Sea, were produced by subduction of both the North and South American Plates beneath the Caribbean Plate.
Iceland, which rose from the sea 16 million years ago, has resulted from volcanism along the mid Atlantic Ridge (where the spreading Atlantic continues to rift North America from Eurasia); indeed, this island nation straddles the two Continental Plates. A third type of volcanic island, produced by a mantle plume, can develop far from any plate margin; the Hawaiian Island chain, the Galapagos Islands, the Azores and Easter Island are examples of such isolated "hotspot" volcanism.
Of course, all of these islands are prone to continued volcanic activity, even after hundreds or thousands of years of quiescence; only hotspot islands that have been transported away from the mantle plume (by movement of their oceanic plate) are immune to reawakening. Earth's landscape continues to evolve and humans are finally around to observe it!
Friday, July 4, 2008
Rock Rabbits
Anyone who has been hiking above timberline in the Western mountains has likely heard the loud, high-pitched call of the pika. Resembling a chunky, large-eared hamster, pikas are actually members of the rabbit family; a variety of species are found across the globe and are also known as coneys or rock rabbits.
Favoring rocky slopes and boulder fields, pikas spend much of the day foraging for alpine vegetation which they add to their sheltered haystacks; once the plant material dries out, they take it into their burrows for bedding and nourishment. When not gathering food, these cold-loving mammals perch on boulders to survey and protect their territory. Despite their small size, pikas remain active through the winter, relying on lichen and matted alpine plants if their hay supply runs out.
Usually mating by mid spring, females give birth to 3-4 young after a four-week gestation and nurse them for another month. By then, the young pikas are on their own and, if not killed by golden eagles, hawks, coyotes or weasels, will be full grown by the end of summer. Adult females often raise a second litter after the first group leaves the den.
Favoring rocky slopes and boulder fields, pikas spend much of the day foraging for alpine vegetation which they add to their sheltered haystacks; once the plant material dries out, they take it into their burrows for bedding and nourishment. When not gathering food, these cold-loving mammals perch on boulders to survey and protect their territory. Despite their small size, pikas remain active through the winter, relying on lichen and matted alpine plants if their hay supply runs out.
Usually mating by mid spring, females give birth to 3-4 young after a four-week gestation and nurse them for another month. By then, the young pikas are on their own and, if not killed by golden eagles, hawks, coyotes or weasels, will be full grown by the end of summer. Adult females often raise a second litter after the first group leaves the den.
Thursday, July 3, 2008
Storm Trains
Last evening, a cold front stretched from the Central Plains to southern Michigan, separating warm, humid air, to its south, from cooler and drier air behind the front. Not associated with a potent storm system, the front was relatively stationary, drifting very slowly to the south and east.
Disturbances along the front produced thunderstorms and, as they mushroomed into higher levels of the atmosphere, these storms were nudged eastward by strong, upper level winds that paralleled the front. In concert, another storm would develop at the disturbance; this ongoing process produced linear bands of thunderstorms which, moving eastward, dropped heavy rains across the same locations.
Such "training" can lead to copious rainfall and local flooding. Two to three inches per hour fell in the Greater Kansas City area while parts of lower Michigan received nearly five inches of rain. Meanwhile, wildfires plague the Southwest and parts of the Southeast remain mired in a multi-year drought.
Disturbances along the front produced thunderstorms and, as they mushroomed into higher levels of the atmosphere, these storms were nudged eastward by strong, upper level winds that paralleled the front. In concert, another storm would develop at the disturbance; this ongoing process produced linear bands of thunderstorms which, moving eastward, dropped heavy rains across the same locations.
Such "training" can lead to copious rainfall and local flooding. Two to three inches per hour fell in the Greater Kansas City area while parts of lower Michigan received nearly five inches of rain. Meanwhile, wildfires plague the Southwest and parts of the Southeast remain mired in a multi-year drought.
Tuesday, July 1, 2008
Geologic Basins
Novice geologists who visit a region such as the Permian Basin of West Texas might be surprised to find that the area does not resemble a broad valley. Geologic basins refer to the shape of the deep sediment formations and to their deposition in a structural bowl of ancient Precambrian or early Paleozoic bedrock. In the case of the Permian Basin, a thick layer of Permian sea sediments collected within such a basin; now covered over by Mesozoic and Cenozoic strata (which have been sculpted into the West Texas landscape by wind and water erosion) the deeper Permian rocks are tapped for their rich oil and gas deposits.
Further north, the Michigan Basin is often confused with the glacial-carved basin of Lake Michigan (a shallow surface feature). Rather, centered over Lower Michigan, this geologic basin extends from western New York to eastern Wisconsin and from Upper Michigan to northern Ohio. This broad bowl of Precambrian bedrock has gradually filled in with Paleozoic and Mesozoic sediments; as layers were added over a span of 400 million years, the basin closed in from the periphery and the youngest deposits (Jurassic in age) lie in the central part of Lower Michigan. Lakes Michigan, Erie and Huron, the varied topography of Michigan and Niagara Falls are all erosion-produced surface features of the Basin.
In northeastern Wyoming and southeastern Montana, the Powder River Basin is famous for its vast supply of low-sulfur coal. Derived from swamplands of the late Cretaceous and early Tertiary Periods, this coal is near the surface of a wide geologic basin that underlies the region and includes deposition layers that date back to the Precambrian Era. Unlike the other examples discussed above, Powder River is also a topographic basin, a broad valley that has been eroded from the surrounding landscape by the River and its tributaries; indeed, this erosion of soft, overlying Tertiary deposits has made the Powder River coal especially accessible.
Further north, the Michigan Basin is often confused with the glacial-carved basin of Lake Michigan (a shallow surface feature). Rather, centered over Lower Michigan, this geologic basin extends from western New York to eastern Wisconsin and from Upper Michigan to northern Ohio. This broad bowl of Precambrian bedrock has gradually filled in with Paleozoic and Mesozoic sediments; as layers were added over a span of 400 million years, the basin closed in from the periphery and the youngest deposits (Jurassic in age) lie in the central part of Lower Michigan. Lakes Michigan, Erie and Huron, the varied topography of Michigan and Niagara Falls are all erosion-produced surface features of the Basin.
In northeastern Wyoming and southeastern Montana, the Powder River Basin is famous for its vast supply of low-sulfur coal. Derived from swamplands of the late Cretaceous and early Tertiary Periods, this coal is near the surface of a wide geologic basin that underlies the region and includes deposition layers that date back to the Precambrian Era. Unlike the other examples discussed above, Powder River is also a topographic basin, a broad valley that has been eroded from the surrounding landscape by the River and its tributaries; indeed, this erosion of soft, overlying Tertiary deposits has made the Powder River coal especially accessible.
Monday, June 30, 2008
Canadian Rescue
Cool, dry air pushed into Missouri over the past 48 hours, courtesy of a Canadian cold front. Displacing the hot, muggy air that enveloped us for most of the week, it was a refreshing and invigorating change. Yard work was a pleasure and the desire for exercise returned. One could almost imagine that the leaves were beginning to turn or that the rumble in the distance came from the University's marching band. Even the scent of neighborhood cookouts suggested pregame tailgates.
Then I remembered: we still have to get through July and August! An escape to Colorado and a planned trip to Newfoundland should ease the burden. Life can be tough.
Then I remembered: we still have to get through July and August! An escape to Colorado and a planned trip to Newfoundland should ease the burden. Life can be tough.
Sunday, June 29, 2008
Evening on the Floodplain
Cool, dry air, clear skies and a flooded landscape characterized the Missouri River Valley last evening. A raft of flotsam had collected behind the Perche Creek bridge, attracting a pair of red-headed woodpeckers that hopped among the logs, picking off insects. A flock of cliff swallows, temporarily evicted from their homes beneath the bridge, gathered on nearby power lines.
Out in the Eagle Bluffs Conservation Area, shallow pools covered most of the fields and the permanent waterways lapped against the levees. Waterfowl had dispersed across the flooded valley and were represented by only a few Canada geese and a mother wood duck with her maturing brood. Great blue herons, like posted sentries, guarded the shallows and turkey vultures soared low above the fields, searching for stranded fish. Indigo buntings sang from roadside saplings while lark sparrows and horned larks scoured the gravel for windblown seeds.
A lone red-tailed hawk circled above the refuge, perhaps over-whelmed by the numerous cottontails that emerged from thickets as dusk enveloped the floodplain. Mammals were otherwise limited to a few deer on distant meadows and the occasional muskrat that motored across the lakes. While the extensive flooding produced scenic vistas and a peaceful landscape, it had clearly sent many creatures to higher ground.
Out in the Eagle Bluffs Conservation Area, shallow pools covered most of the fields and the permanent waterways lapped against the levees. Waterfowl had dispersed across the flooded valley and were represented by only a few Canada geese and a mother wood duck with her maturing brood. Great blue herons, like posted sentries, guarded the shallows and turkey vultures soared low above the fields, searching for stranded fish. Indigo buntings sang from roadside saplings while lark sparrows and horned larks scoured the gravel for windblown seeds.
A lone red-tailed hawk circled above the refuge, perhaps over-whelmed by the numerous cottontails that emerged from thickets as dusk enveloped the floodplain. Mammals were otherwise limited to a few deer on distant meadows and the occasional muskrat that motored across the lakes. While the extensive flooding produced scenic vistas and a peaceful landscape, it had clearly sent many creatures to higher ground.
Saturday, June 28, 2008
The Nature of God
Once hominids were intelligent enough to wonder, the concept of God was born. By then, the Universe was already 13.6 billion years old.
Since that time, God has been the target of man's hope and the refuge from his fear. Early human civilizations worshipped numerous gods, each associated with specific needs and threats. Rituals, designed to appease these divine powers, became an integral part of their culture. Modern, Western religions, though monotheistic and based on a humanized God, were established before the scientific revolution and retain a focus on ritual.
Science cannot prove nor disprove the existence of God but it does lend perspective to man's interpretation of the natural world. We now know that the Earth is not flat; it does not lie at the center of the Universe, nor at the center of our galaxy, nor even at the center of our solar system. We have come to understand the natural forces that shape our planet and the evolutionary processes that produced our species. There is, of course, still room for faith in a Divine Architect, but I am inclined to believe that God is Nature; I reject the vindictive, judgemental, ritualized God of Western culture.
Since that time, God has been the target of man's hope and the refuge from his fear. Early human civilizations worshipped numerous gods, each associated with specific needs and threats. Rituals, designed to appease these divine powers, became an integral part of their culture. Modern, Western religions, though monotheistic and based on a humanized God, were established before the scientific revolution and retain a focus on ritual.
Science cannot prove nor disprove the existence of God but it does lend perspective to man's interpretation of the natural world. We now know that the Earth is not flat; it does not lie at the center of the Universe, nor at the center of our galaxy, nor even at the center of our solar system. We have come to understand the natural forces that shape our planet and the evolutionary processes that produced our species. There is, of course, still room for faith in a Divine Architect, but I am inclined to believe that God is Nature; I reject the vindictive, judgemental, ritualized God of Western culture.
Friday, June 27, 2008
Colorado's Jays
Five species of jay inhabit Colorado. All are noisy, aggressive and omnivorous birds but each is associated with a unique life zone; as is usual in nature, the borders of their range tend to overlap.
Blue jays, common throughout eastern and central North America, spread into Colorado via the South Platte and Arkansas Valleys and are now common along the Front Range urban corridor; they are easily found along wooded streams and in residential areas. Scrub jays inhabit foothill shrublands and lower canyons throughout the State, generally at elevations between six and seven thousand feet. In the higher foothills and mountains, Steller's jays are found, favoring the ponderosa parklands and Douglas fir forests that dominate the vegetation of the Montane Zone (roughly 7-9000 feet); they may be seen as high as timberline in summer and occasionally descend to the Plains in winter.
Gray jays, also known as Canadian jays, prefer the high forests of the Subalpine and Hudsonian Zones, between 9000 and 11,500 feet. Inquisitive and rather tame, they often visit picnic areas and ski resorts, seeking handouts or grabbing leftovers. Finally, pinyon jays favor the dry, open country of southern and western Colorado where, as their name implies, they roam among pinyon-juniper woodlands; unlike the other jay species, they tend to move about in sizable flocks and, from a distance, are often mistaken for crows.
Blue jays, common throughout eastern and central North America, spread into Colorado via the South Platte and Arkansas Valleys and are now common along the Front Range urban corridor; they are easily found along wooded streams and in residential areas. Scrub jays inhabit foothill shrublands and lower canyons throughout the State, generally at elevations between six and seven thousand feet. In the higher foothills and mountains, Steller's jays are found, favoring the ponderosa parklands and Douglas fir forests that dominate the vegetation of the Montane Zone (roughly 7-9000 feet); they may be seen as high as timberline in summer and occasionally descend to the Plains in winter.
Gray jays, also known as Canadian jays, prefer the high forests of the Subalpine and Hudsonian Zones, between 9000 and 11,500 feet. Inquisitive and rather tame, they often visit picnic areas and ski resorts, seeking handouts or grabbing leftovers. Finally, pinyon jays favor the dry, open country of southern and western Colorado where, as their name implies, they roam among pinyon-juniper woodlands; unlike the other jay species, they tend to move about in sizable flocks and, from a distance, are often mistaken for crows.
Thursday, June 26, 2008
Steam Bath
Less than a week past the summer solstice, I'm ready for September. Hot, humid weather has settled into Missouri, with highs near 90 and dew points in the seventies. Though I appreciate seasonal change, such conditions sap my energy and I long for the next wave of cool, Canadian air.
Of course, there's still plenty to see and explore on these muggy, summer days. The mimosas and elderberries are in bloom, insects are peaking in number and variety and frequent thunderstorms keep the weather interesting (though their rains boost the humidity). While I admire the swifts and swallows that thrive in this Midwestern steam bath, I'll limit my outdoor jaunts to the early morning and evening hours. Man may have evolved in such a climate but I feel out of place.
A cold front is due by the weekend and the humidity should drop significantly. Until then, I'll get some reading done and appreciate my indoor job.
Of course, there's still plenty to see and explore on these muggy, summer days. The mimosas and elderberries are in bloom, insects are peaking in number and variety and frequent thunderstorms keep the weather interesting (though their rains boost the humidity). While I admire the swifts and swallows that thrive in this Midwestern steam bath, I'll limit my outdoor jaunts to the early morning and evening hours. Man may have evolved in such a climate but I feel out of place.
A cold front is due by the weekend and the humidity should drop significantly. Until then, I'll get some reading done and appreciate my indoor job.
Wednesday, June 25, 2008
Pine Mountain
In southeastern Kentucky, two high ridges, separated by the Cumberland River Valley, parallel the Virginia border. These prominent spines are part of the Cumberland Mountains, the southeast edge of the Appalachian Plateau and the westward extension of the Allegheny Front. The more southern ridge is Cumberland Mountain which harbors the famous Cumberland Gap, just outside of Middlesboro, Kentucky.
The northern ridge, extending from Whitesburg, Kentucky southwestward into Tennessee, is known as Pine Mountain; after flowing along the south side of this ridge, the Cumberland River cuts through to its north side at Pineville and continues westward to Cumberland Falls and Lake Cumberland. Pine Mountain State Resort Park, just west of Pineville, is an excellent place to explore the ridge; it is the oldest Park in what is arguably the finest State Park system in the country. Numerous trails lead across the south face and atop the high spine of Pine Mountain, passing waterfalls, a natural bridge and scenic rock formations; "chained rock," reached by a short walk or a long hike, yields a spectacular view of the nearby mountains and valleys.
Further east, via KY 1254 off U.S. 119, Kingdom Come State Park sits atop Pine Mountain; at an elevation of 2800 feet, it is the highest of Kentucky's State Parks. Centered on Raven Rock, a giant outcrop of sandstone, the Park is accessed by a fine network of trails which lead across the mountain slopes and out to several overlooks. The Little Shepherd Trail, which follows the crest of Pine Mountain for 38 miles (from U.S. 421 to U.S. 119), crosses through the Park.
Even further east, the Bad Branch State Nature Preserve spreads up the south face of Pine Mountain. Reached via KY 932 (off U.S. 119, 7 miles southwest of Whitesburg), the refuge is renowned for Bad Branch Falls, a 60 foot cascade. Energetic and conditioned hikers may also want to set their sights on High Rock, atop the Pine Mountain ridge.
The northern ridge, extending from Whitesburg, Kentucky southwestward into Tennessee, is known as Pine Mountain; after flowing along the south side of this ridge, the Cumberland River cuts through to its north side at Pineville and continues westward to Cumberland Falls and Lake Cumberland. Pine Mountain State Resort Park, just west of Pineville, is an excellent place to explore the ridge; it is the oldest Park in what is arguably the finest State Park system in the country. Numerous trails lead across the south face and atop the high spine of Pine Mountain, passing waterfalls, a natural bridge and scenic rock formations; "chained rock," reached by a short walk or a long hike, yields a spectacular view of the nearby mountains and valleys.
Further east, via KY 1254 off U.S. 119, Kingdom Come State Park sits atop Pine Mountain; at an elevation of 2800 feet, it is the highest of Kentucky's State Parks. Centered on Raven Rock, a giant outcrop of sandstone, the Park is accessed by a fine network of trails which lead across the mountain slopes and out to several overlooks. The Little Shepherd Trail, which follows the crest of Pine Mountain for 38 miles (from U.S. 421 to U.S. 119), crosses through the Park.
Even further east, the Bad Branch State Nature Preserve spreads up the south face of Pine Mountain. Reached via KY 932 (off U.S. 119, 7 miles southwest of Whitesburg), the refuge is renowned for Bad Branch Falls, a 60 foot cascade. Energetic and conditioned hikers may also want to set their sights on High Rock, atop the Pine Mountain ridge.
Tuesday, June 24, 2008
Clifton Gorge
Slicing through the farmlands of southwestern Ohio, Clifton Gorge is a scenic wonderland for naturalists. Though its rugged walls of Silurian dolomite were deposited 400 million years ago, the gorge itself was carved by a torrent of glacial meltwater near the end of the Pleistocene, some 12,000 years ago. Documenting this history, the shaded walls of the chasm harbor relict, periglacial vegetation, including hemlock, Canadian yew, arborvitae and mountain maple.
Stands of chinquapin oak cover south-facing hillsides and over 340 species of wildflower have been found in the gorge. Numerous springs and seeps produce ideal conditions for the sixteen species of fern that grace the rocky walls and provide ideal habitat for salamanders (8 species live here). Red squirrels are common in the hemlock areas and, as one might expect, a large variety of songbirds are drawn to this chasm, which offers protection in winter and a cool retreat in summer.
Hikers will find an excellent trail network at Clifton Gorge; these footpaths skirt the rim, snake down the rugged walls and run along the canyon floor, following and crossing the Little Miami River, where slump blocks of dolomite rest along and within the stream. Dedicated in 1973, Clifton Gorge State Nature Preserve merges with John Bryan State Park, which encompasses the western portion of the gorge. Access to both areas is off State Route 343, between Yellow Springs and Clifton; a parking lot off Jackson Street, on the west edge of Clifton, is closest to the scenic "Narrows" of Clifton Gorge.
Stands of chinquapin oak cover south-facing hillsides and over 340 species of wildflower have been found in the gorge. Numerous springs and seeps produce ideal conditions for the sixteen species of fern that grace the rocky walls and provide ideal habitat for salamanders (8 species live here). Red squirrels are common in the hemlock areas and, as one might expect, a large variety of songbirds are drawn to this chasm, which offers protection in winter and a cool retreat in summer.
Hikers will find an excellent trail network at Clifton Gorge; these footpaths skirt the rim, snake down the rugged walls and run along the canyon floor, following and crossing the Little Miami River, where slump blocks of dolomite rest along and within the stream. Dedicated in 1973, Clifton Gorge State Nature Preserve merges with John Bryan State Park, which encompasses the western portion of the gorge. Access to both areas is off State Route 343, between Yellow Springs and Clifton; a parking lot off Jackson Street, on the west edge of Clifton, is closest to the scenic "Narrows" of Clifton Gorge.
Monday, June 23, 2008
A Feast of Froglets
On our visit to the Forum Nature Area, yesterday, my wife and I found a zillion froglets along the marshy shores of the flooded, seasonal lake. While most appeared to be young leopard frogs, they were difficult to observe, springing from the wet vegetation like hordes of grasshoppers. Within the shallows, other frogs were in various states of metamorphosis, from tadpoles with legs to froglets with tails. Once they transform from a reliance on gills to the use of lungs, the froglets emerge from the water to feed on insects, diving back when danger is sensed.
These swarms of froglets highlight the abundance of life in our rich, unspoiled wetlands and provide natural entertainment for adults and children alike. More importantly, they offer a feast for the herons, snakes, snapping turtles, mink and raccoons that prey on these amphibians. Those that survive will grow rapidly through the summer, doing their part to control the wide variety of insects that inhabit and breed in the wetland. As autumn approaches and the waters cool, the adult frogs will settle into the bottom muck until the warm days and heavy rains of spring revive the marsh.
These swarms of froglets highlight the abundance of life in our rich, unspoiled wetlands and provide natural entertainment for adults and children alike. More importantly, they offer a feast for the herons, snakes, snapping turtles, mink and raccoons that prey on these amphibians. Those that survive will grow rapidly through the summer, doing their part to control the wide variety of insects that inhabit and breed in the wetland. As autumn approaches and the waters cool, the adult frogs will settle into the bottom muck until the warm days and heavy rains of spring revive the marsh.
Sunday, June 22, 2008
The Cost of Oil
The price of oil has surged in recent months, producing hardships for individuals and businesses alike. The cause for this phenomenon appears to be mulifactorial: increasing worldwide demand (especially in developing nations), political unrest in oil producing countries, limited refinery capacity, speculation and a diminished U.S. dollar are all playing a role. But, despite the pain levied on consumers, we are, in many ways, beginning to appreciate the true cost of using oil as fuel.
Though I have some personal doubts regarding the degree to which human industry is responsible for global warming, there is little doubt that we are have produced 100% of the environmental pollution; the procurement, transport and burning of fossil fuels have contributed significantly to the pollution and destruction of natural habitat. Recognizing that high oil prices and consumer stress are providing an opportunity, U.S. oil companies are renewing their efforts to drill in ANWR and other environmentally-sensitive areas. But, as we and they know, the benefits from such a policy change would not be realized for years and, by then, the worldwide demand would absorb any increased production.
There is evidence that the higher cost of oil is beginning to change our lifestyle. Auto use is down, train cargo transport is up, mass transit ridership is increasing and the shift to clean, renewable energy sources is getting a much-needed boost. Hopefully, such trends, combined with conservation measures, will end our long love affair with fossil fuels.
Though I have some personal doubts regarding the degree to which human industry is responsible for global warming, there is little doubt that we are have produced 100% of the environmental pollution; the procurement, transport and burning of fossil fuels have contributed significantly to the pollution and destruction of natural habitat. Recognizing that high oil prices and consumer stress are providing an opportunity, U.S. oil companies are renewing their efforts to drill in ANWR and other environmentally-sensitive areas. But, as we and they know, the benefits from such a policy change would not be realized for years and, by then, the worldwide demand would absorb any increased production.
There is evidence that the higher cost of oil is beginning to change our lifestyle. Auto use is down, train cargo transport is up, mass transit ridership is increasing and the shift to clean, renewable energy sources is getting a much-needed boost. Hopefully, such trends, combined with conservation measures, will end our long love affair with fossil fuels.
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