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Pottsville-capped Spruce Knob in West Virginia South of Mount Porte Crayon and Seneca Creek, the Appalachian structural front is less clearly unified. Pottsville-capped Spruce Mountain , south and east of Seneca Creek, continues the Allegheny Front's geology southward; [ 5 ] this ridge reaches an elevation of 4,863 feet (1,482 m) at Spruce Knob ...
Prominent peaks of Spruce Mountain, north to south, are Horse Rock (4,536 ft; 1,383 m), Spruce Mountain Peak (4,586 ft; 1,398 m), Picea Benchmark (4,613 ft; 1,406 m), and Spruce Knob itself. Spruce Knob is the highest point in the eastern United States between the Adirondacks of New York and Mount Rogers (part of the Blue Ridge Mountains) in ...
Laid down as sediment on a sea floor 440 million years ago, in West Virginia the Tuscarora is 150 to 250 feet (76 m) thick. At the River Knobs, the quartzite layer has been "verticalized" by geological forces during the formation of the Appalachians some 230 million years ago.
Around 480 million years ago, geologic processes began that led to three distinct orogenic eras that created much of the surface structure seen in today's Appalachians. [ d ] During this period, mountains once reached elevations similar to those of the Alps and the Rockies before natural erosion occurred over the last 240 million years leading ...
The period is bracketed between the Permian–Triassic extinction event and the Triassic–Jurassic extinction event, two of the "big five", and it is divided into three major epochs: Early, Middle, and Late Triassic. [11] The Early Triassic, about 252 to 247 million years ago, was dominated by deserts in the interior of the Pangaea supercontinent.
The Cretaceous (IPA: / k r ɪ ˈ t eɪ ʃ ə s / krih-TAY-shəss) [2] is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77 million years, it is the ninth and longest geological period of the entire Phanerozoic.
Sometime between about 1,100 and 800 million years ago, lava was deposited in the extreme eastern part of the State forming our oldest exposed rock, the Catoctin Greenstone. Later, perhaps about 800 million years ago, a narrow trough began to form in extreme eastern West Virginia. An arm of the sea entered and sediments accumulated. As time ...
The first period was a lengthy period of geologic instability from the origin of the planet until roughly 1,100 million years ago. During this time, the state's Precambrian bedrock was formed by volcanism and the deposition of sedimentary rock and then modified by processes such as faulting , folding and erosion .