Approximately 350 million to 300 million years ago, in the Carboniferous period, the combined continents of Europe and Africa (Gondwana) collided with North America to form the supercontinent of Pangaea. This collision exerted massive stress on what is today the Eastern Seaboard of North America, resulting in a large-scale uplift of the entire region. Closer to the boundary between the colliding plates, tectonic stresses contributed to the metamorphosizing of the rock (i.e. the transformation of igneous and sedimentary rock into metamorphic rock).
The Appalachian Orogeny is responsible for the creation of the mountains themselves and is not responsible for the topography that now typifies the Piedmont and coastal plain regions east of the mountain chain. The immense region involved in the continental collision, the vast temporal length of the orogeny and the thickness of the pile of sediments and igneous rocks known to have been involved are evidence that at the peak of the mountain-building process, the Appalachians could have risen as high or perhaps even higher than the present-day Himalaya.
Evidence for the Appalachian orogeny stretches for many hundreds of miles on the surface from Alabama to New Jersey and can be traced further subsurface to the southwest. In the north it enters a region of confused topography associated with earlier orogenies, but clearly the Applachian deformation extends northeast to Newfoundland.
The Avalon Peninsula is a large peninsula that makes up the southeast portion of the island of Newfoundland. The peninsula was one of the first European inhabited areas in North America, with the first permanent settlement established at Cuper's Cove in 1610. Sir George Calvert was later given a large land holding on the peninsula. The initial colony of Ferryland grew to a population of 100 becoming the first successful permanent settlement on Newfoundland island. In 1623 Calvert was given a Royal Charter extending his lands and granting them the name Province of Avalon "in imitation of Old Avalon in Somersetshire wherein Glassenbury stands, the first fruits of Christianity in Britain as the other was in that party of America." The charter created the province as a palatinate in which Calvert had absolute authority.
The process of orogeny can take tens of millions of years and build mountains from plains or even the ocean floor. Orogeny can occur due to continental collision or volcanic activity. Frequently, rock formations that undergo orogeny are severely deformed and undergo metamorphism. During orogeny, deeply buried rocks may be pushed to the surface. Sea bottom and near shore material may cover some or all of the orogenic area. If the orogeny is due to two continents colliding, the resulting mountains can be very high. The physiography of Orogeny usually produces long linear structures, known as orogenic belts. Orogenic belts are associated with subduction zones, which consume crust, produce volcanoes, and build island arcs. These island arcs may be added to a continent during an orogenic event.
The Carboniferous is a major division of the geologic timescale that extends from the end of the Devonian period, about 359.2 Ma (million years ago), to the beginning of the Permian period, about 299.0 Ma. having extensive coal beds of that age found in Great Britain and Western Europe. The first third of the Carboniferous is called the Mississippian epoch, and the remainder is called the Pennsylvanian. Conifer trees were introduced in this important and well-known time period. The Carboniferous introduced more geological notions than the mesozoic. In North America, the Mississippi epoch was where the interval consists primarily of marine limestones and likely uniform conditions of Atlantic isles. In Europe, the Mississippian and Pennsylvanian epochs are one more-or-less continuous sequence of lowland continental deposits and are lumped together as the Carboniferous period.
As the Taconic Orogeny subsided in early Silurian time, uplifts and folds in the Hudson Valley region were beveled by erosion. Upon this surface sediments began to accumulate, derived from remaining uplifts in the New England region. The evidence for this is the Silurian Shawangunk Conglomerate, a massive, ridge-forming quartz sandstone and conglomerate formation, which rests unconformably on a surface of older gently- to steeply-dipping pre-Silurian age strata throughout the region. This ridge of Shawangunk Conglomerate extends southward from the Hudson Valley along the eastern front of the Catskills. It forms the impressive caprock ridge of the Shawangunk Mountains west of New Paltz (town), New York. To the south and west it becomes the prominent ridge-forming unit that crops out along the crest of Kittatinny Mountain in New Jersey.
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The term Appalachia is often used more restrictively to refer to regions in the central and southern Appalachian Mountains, usually including areas in the states of Kentucky, Tennessee, Virginia, West Virginia, and North Carolina, and sometimes extending as far south as northern Georgia and western South Carolina, as far north as Pennsylvania, and as far west as southeastern Ohio. Only by way of the Hudson and Mohawk Valleys, and round about the southern termination of the system were there easy routes to the interior of the country, and these were long closed by powerful Native American tribes such as the Iroquois, Creek, and Cherokee, among others. British expansion was also blocked by Spanish colonies in the south and French activity throughout the interior. In eastern Pennsylvania the Great Appalachian Valley, or Great Valley, was accessible by reason of a broad gateway between the end of South Mountain and the Highlands, and here between the Susquehanna and Delaware Rivers settled many Germans and Moravians, whose descendants even now retain the peculiar patois known as "Pennsylvania Dutch". |
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