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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 ...
The Ca-Al-rich inclusions, which formed 2 million years before the chondrules, [1] are a key signature of a supernova explosion. c. 4,567 ±3 Ma – Rapid collapse of hydrogen molecular cloud , forming a third-generation Population I star , the Sun , in a region of the Galactic Habitable Zone (GHZ), about 25,000 light years from the center of ...
The numeric values on the International Chronostratigrahpic Chart are represented by the unit Ma (megaannum, for 'million years'). For example, 201.4 ± 0.2 Ma, the lower boundary of the Jurassic Period, is defined as 201,400,000 years old with an uncertainty of 200,000 years.
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 ...
Late Devonian: 375 million years ago, 75% of species lost, including most trilobites; End Permian, The Great Dying: 251 million years ago, 96% of species lost, including tabulate corals, and most trees and synapsids; End Triassic: 200 million years ago, 80% of species lost, including all conodonts
Researchers have wondered how an alligator-size arthropod lived more than 300 million years ago. The discovery of an intact Arthropleura head offers new insights. World’s largest arthropod lived ...
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.