A summit is a point on a surface, higher in elevation than all points adjacent to it. The topographic terms acme, apex and zenith are synonymous; the term top is used only for a mountain peak, located at some distance from the nearest point of higher elevation. For example, a big massive rock next to the main summit of a mountain is not considered a summit. Summits near a higher peak, with some prominence or isolation, but not reaching a certain cutoff value for the quantities, are considered subsummits of the higher peak, are considered part of the same mountain. A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top. Summit may refer to the highest point along a line, trail, or route; the highest summit in the world is Everest with height of 8844.43 m above sea level. The first official ascent was made by Sir Edmund Hillary, they reached the mountain`s peak in 1953. Whether a highest point is classified as a summit, a sub peak or a separate mountain is subjective; the UIAA definition of a peak is.
Otherwise, it's a subpeak. In many parts of the western United States, the term summit refers to the highest point along a road, highway, or railroad. For example, the highest point along Interstate 80 in California is referred to as Donner Summit and the highest point on Interstate 5 is Siskiyou Mountain Summit. A summit climbing differs from the common mountaineering. Summit expedition requires: 1+ year of training, a good physical shape, a special gear. Although a huge part of climber’s stuff can be left and taken at the base camps or given to porters, there is a long list of personal equipment. In addition to common mountaineers’ gear, Summit climbers need to take Diamox and bottles of oxygen. There are special requirements for crampons, ice axe, rappel device, etc. Geoid Hill – Landform that extends above the surrounding terrain Nadir Summit accordance Peak finder Summit Climbing Gear List
Notch Peak is a distinctive summit located on Sawtooth Mountain in the House Range, west of Delta, United States. The peak and the surrounding area are part of the Notch Peak Wilderness Study Area. Bristlecone pines, estimated to be 3,000 to 4,000 years old, are located on the ridges surrounding Notch Peak. Notch Peak is one of the highest peaks in the House Range, reaching 9,658 feet NAVD 88; the northwest face of the mountain is a massive carbonate rock cliff with 2,200 feet of vertical rise, making it among the highest cliff faces in North America. Overall, the summit rises about 4,450 feet above Tule Valley, it is the second highest pure vertical drop in the United States after El Capitan. as well as the highest carbonate rock cliff in North America. One of the more popular uses of the area is the hike to Notch Peak so you can look down the notch in person; the summit can be reached by following a trail from the east side of the mountain in Sawtooth Canyon. The hike is about 7.5 miles round trip, with 2,600 feet elevation gain.
The north face of Notch Peak is divided by a large shelf into lower wall. There are several rock climbing routes on the limestone cliffs. "The Swiss Route", "Direct North West Ridge, "Book of Saturdays" ascend the upper wall. On the lower wall "Appetite for Destruction" and "Western Hardman" reach 900 feet of vertical. Climbing on all of these routes is adventurous with rockfall hazard and loose flakes of varying size. In addition to the face of Notch Peak, the granite found in the canyon below the notch is used for climbing; this part of the House Range is chiefly made up of a passive margin sequence of Cambrian to Ordovician carbonate rocks. The top of the range is the type section for the aptly named Notch Peak Dolomite. At the base of the range is the pink/orange Notch Peak granite and monzonite, Jurassic in age. Around Notch Peak from the west side, white Lake Bonneville fossiliferous marls occur; because of the intrusion, a hike up the canyon below the notch can show a well-developed metamorphic aureole and inter-fingering textures between the intrusion and the bedrock.
Small quantities of tungsten and placer gold have been found around the Notch Peak area. "Notch Peak". SummitPost.org
Lake Bonneville was a prehistoric pluvial lake that covered much of the eastern part of North America's Great Basin region. Most of the territory it covered was in present-day Utah, though parts of the lake extended into present-day Idaho and Nevada. Lake Bonneville existed until about 14,500 years ago, when a large portion of the lake was released through the Red Rock Pass in Idaho. Following the Bonneville flood, as the release is now known, the lake receded to a level called the Provo Level. Many of the unique geological characteristics of the Great Basin are due to the effects of the lake. At more than 1,000 ft deep and more than 19,691 square miles in area, the lake was nearly as extensive as Lake Michigan and deeper. With the change in climate, the lake began drying up, leaving Great Salt Lake, Utah Lake, Sevier Lake, Rush Lake, Little Salt Lake as remnants. Lake Bonneville was named by the geologist G. K. Gilbert after Benjamin Louis Eulalie de Bonneville, a French-born officer in the United States Army, a fur trapper, explorer in the American West.
Bonneville was noted for his expeditions to the Great Basin. Like most, if not all, of the ice age pluvial lakes of the American West, Lake Bonneville was a result of the combination of lower temperatures, decreased evaporation, higher precipitation that prevailed in the region because of a more southerly jet stream than today's; the lake was not a singular entity either. Great Salt Lake, Utah Lake, Sevier Lake are the largest remnants of the original Lake Bonneville. Several levels of the old shorelines are still visible above Salt Lake City, along the Wasatch Front and elsewhere; the appearance of the shorelines is that of a shelf or bench protruding from the mountainside, well above the valley floor. Four main shorelines are associated with the fluctuating levels of the ancient lake; the Stansbury, Bonneville and Gilbert shorelines each mark a time when lake level remained constant long enough to deposit massive accumulations of sand and gravel. The Bonneville Bench, at about 5,102 feet above sea level, is part of the preserved ice age shoreline.
This shoreline marks the highest level attained by the Pleistocene lake 15,500 years ago. During this period, the lake was over 980 ft deep in places. About 14,500 years ago, the lake level fell catastrophically as Lake Bonneville overflowed near Red Rock Pass and washed away a natural dam formed by opposing overlapping alluvial fans; the lake level fell some 344 ft to what is now the next lower bench in a flood that geologists estimate to have lasted up to a year. It is estimated; the Provo level is the most recognized shoreline feature throughout the Bonneville basin and is distinguished by thick accumulations of tufa that formed near the shorelines during the 500 years that the lake was at this level. During this period, the Red Rock Pass contained a river carrying water overflowing out of Lake Bonneville into the Snake River. About 14,000 years ago, the lake started to drop again because of changing climate conditions, by 12,000 years ago, the lake reached a level lower than that of the modern day Great Salt Lake.
A slight transgression or rise in lake level occurred about 10,900 to 10,300 years ago and formed the Gilbert shoreline. The Gilbert shoreline is the least conspicuous of the major shorelines but evidence of it remains at Antelope Island and in large coastal features, such as the Fingerpoint Spit near the Hogup Mountains. In addition to geological traces, the lake has left a legacy of related fish distributed in now-isolated bodies of water; the term "Lake Bonneville drainage" is used to refer to the assembly of disconnected lakes and rivers. List of prehistoric lakes Lake Lahontan Bonneville cutthroat trout: endemic to area covered by Lake Bonneville Bonneville Salt Flats Brigham Young University - Geology - maps of Lake Bonneville Utah Geologic Survey- maps of Lake Bonneville
The Cambrian Period was the first geological period of the Paleozoic Era, of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago to the beginning of the Ordovician Period 485.4 mya. Its subdivisions, its base, are somewhat in flux; the period was established by Adam Sedgwick, who named it after Cambria, the Latin name of Wales, where Britain's Cambrian rocks are best exposed. The Cambrian is unique in its unusually high proportion of lagerstätte sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells; as a result, our understanding of the Cambrian biology surpasses that of some periods. The Cambrian marked a profound change in life on Earth. Complex, multicellular organisms became more common in the millions of years preceding the Cambrian, but it was not until this period that mineralized—hence fossilized—organisms became common; the rapid diversification of life forms in the Cambrian, known as the Cambrian explosion, produced the first representatives of all modern animal phyla.
Phylogenetic analysis has supported the view that during the Cambrian radiation, metazoa evolved monophyletically from a single common ancestor: flagellated colonial protists similar to modern choanoflagellates. Although diverse life forms prospered in the oceans, the land is thought to have been comparatively barren—with nothing more complex than a microbial soil crust and a few molluscs that emerged to browse on the microbial biofilm. Most of the continents were dry and rocky due to a lack of vegetation. Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia; the seas were warm, polar ice was absent for much of the period. Despite the long recognition of its distinction from younger Ordovician rocks and older Precambrian rocks, it was not until 1994 that the Cambrian system/period was internationally ratified; the base of the Cambrian lies atop a complex assemblage of trace fossils known as the Treptichnus pedum assemblage. The use of Treptichnus pedum, a reference ichnofossil to mark the lower boundary of the Cambrian, is difficult since the occurrence of similar trace fossils belonging to the Treptichnids group are found well below the T. pedum in Namibia and Newfoundland, in the western USA.
The stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, in Spain. The Cambrian Period was followed by the Ordovician Period; the Cambrian is divided into ten ages. Only three series and six stages are named and have a GSSP; because the international stratigraphic subdivision is not yet complete, many local subdivisions are still used. In some of these subdivisions the Cambrian is divided into three series with locally differing names – the Early Cambrian, Middle Cambrian and Furongian. Rocks of these epochs are referred to as belonging to Upper Cambrian. Trilobite zones allow biostratigraphic correlation in the Cambrian; each of the local series is divided into several stages. The Cambrian is divided into several regional faunal stages of which the Russian-Kazakhian system is most used in international parlance: *Most Russian paleontologists define the lower boundary of the Cambrian at the base of the Tommotian Stage, characterized by diversification and global distribution of organisms with mineral skeletons and the appearance of the first Archaeocyath bioherms.
The International Commission on Stratigraphy list the Cambrian period as beginning at 541 million years ago and ending at 485.4 million years ago. The lower boundary of the Cambrian was held to represent the first appearance of complex life, represented by trilobites; the recognition of small shelly fossils before the first trilobites, Ediacara biota earlier, led to calls for a more defined base to the Cambrian period. After decades of careful consideration, a continuous sedimentary sequence at Fortune Head, Newfoundland was settled upon as a formal base of the Cambrian period, to be correlated worldwide by the earliest appearance of Treptichnus pedum. Discovery of this fossil a few metres below the GSSP led to the refinement of this statement, it is the T. pedum ichnofossil assemblage, now formally used to correlate the base of the Cambrian. This formal designation allowed radiometric dates to be obtained from samples across the globe that corresponded to the base of the Cambrian. Early dates of 570 million years ago gained favour, though the methods used to obtain this number are now considered to be unsuitable and inaccurate.
A more precise date using modern radiometric dating yield a date of 541 ± 0.3 million years ago. The ash horizon in Oman from which this date was recovered corresponds to a marked fall in the abundance of carbon-13 that correlates to equivalent excursions elsewhere in the world, to the disappearance of distinctive Ediacaran fossils. There are arguments that the dated horizon in Oman does not correspond to the Ediacaran-Cambrian boundary, but represents a facies change from marine to evaporite-dominated strata — which w
Elrathia is a genus of ptychopariid trilobite species that lived during the Middle Cambrian of Utah, British Columbia. E. kingii is one of the most common trilobite fossils in the USA locally found in high concentrations within the Wheeler Formation in the U. S. state of Utah. E. Kingii has been considered the most recognizable trilobite. Commercial quarries extract E. kingii in prolific numbers, with just one commercial collector estimating 1.5 million specimens extracted in a 20-year career. 1950 specimens of Elrathia are known from the Greater Phyllopod bed, where they comprise 3.7% of the community. ... trilobite occupied the exaerobic zone, at the boundary of dysoxic bottom waters. E. kingii occur in settings below the oxygen levels required by other contemporaneous epifaunal and infaunal benthic biota and may have derived energy from a food web that existed independently of phototrophic primary productivity. Although other fossil organisms are known to have preferred such environments, E. kingii is the earliest-known inhabitant of them, extending the documented range of the exaerobic ecological strategy into the Cambrian Period."
Though the generic name Elrathia was first published in the combination E. kingii, a species from the House Range Utah, the name, itself, is derived from Elrath, Cherokee County, Alabama. E. kingii is a medium-sized trilobite with a smooth sub-ovate carapace, tapered towards the rear. Thorax is 13 segments. Pygidium has a long terminal piece. Posterior margin of the pygidium has a long broad medial notch. In contrast, E. marjum has 12 segments, 5 axial rings, lacks a notched posterior margin and possess incipient antero-lateral spines. The British Columbian species, E. permulta, is much smaller, averaging about only 20 millimeters, has up to thoracic 14 segments. Because E. permulta lacks several diagnostic features of the genus, it may, in fact, represent a distinct genus. Elrathia is variously known as Elrathina, in fact a separate genus sometimes considered to be a synonym of Ptychoparella, the species E. kingii is erroneously called E. kingi. Hypoxia "Elrathia permulta". Burgess Shale Fossil Gallery.
Virtual Museum of Canada. 2011. "Elrathina cordillerae". Burgess Shale Fossil Gallery. Virtual Museum of Canada. 2011
Cedaria is a small, rather flat trilobite with an oval outline, a headshield and tailshield of the same size, 7 articulating segments in the middle part of the body and spines at the back edges of the headshield that reach halflength of the body. Cedaria lived during the early part of the Upper Cambrian, is abundant in the Weeks Formation. Cedaria has an ovate outline of 1 centimetre or 0.39 inches long on average and ¾ as wide between the tips of the genal spines. The headshield is parabolic in shape with a well defined wide, darker colored border of about 10% of the glabellar length or equal to a thorax segment; the well-defined central raised area tapers forward with a rounded front, but lateral furrows are weakly defined. The backward occipital ring is well defined; the distance between the glabella and the border is ±¼ as long as the glabella or 2× the width of the border. The eyes are kidney-shaped, ±¼ as long as the glabella and midlength of the glabella, close to the glabella; the remaining parts of the cephalon, called free cheeks are flat.
The fracture lines that in moulting separate the librigenae from the fixigenae are divergent just in front of the eyes, becoming parallel near the border furrow and convergent at margin. From the back of the eyes the sutures bends outward and backward, curving backward at the lateral border furrow and cutting the posterior margin in the inner bend of the spine; the articulating middle part of the body has 7 segments, the outer tips bending backwards and darker. The tailshield is semicircular, straight or indented and has a long, tapering axis with 5 or 6 rings, 4 or 5 pleural furrows; the border in the pygidium is as wide as in the cephalon and is often darker, but the border furrow is shallow or absent. Bonneterrina, Cedaria, Paracedaria and Vernaculina together comprise the family Cedariidae. C. buttsi =? Crepicephalus C. woosteri =? C. minor appears in the Upper Cambrian of the United States and Greenland