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Southesk Formation
The Southesk Formation is a stratigraphic unit of Late Devonian (late Frasnian) age. It is present on the western edge of the Western Canada Sedimentary Basin in the Rocky Mountains and foothills of Alberta and southeastern British Columbia. It was named for the Southesk River in Jasper National Park by D.J. McLaren in 1955. The formation consists primarily of dolomite and it preserves fossils of marine animals such as stromatoporoids and rugose corals. Lithology and thickness The Southesk Formation was deposited in reefal environments.Weissenberger, J.A.W. and McIlreath, I.A. 1989. Southesk Cairn reef complex, Upper Devonian (Frasnian), Alberta. In: Reefs: Canada and adjacent areas, H.H.J. Geldsetzer, N.P. James and G.E. Tobbutt (eds.), Canadian Society of Petroleum Geologists, Memoir 13, p. 535-542. It is commonly between 150 and 260 m (490 and 850 feet) thick, and reaches a maximum of about 300 m (1000 feet) in the Flathead area of southeastern British Columbia. It h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratigraphic Unit
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it. Units must be ''mappable'' and ''distinct'' from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%". Lithostratigraphic units Sequences of sedimentary and volcanic rocks are subdivided the basis of their shared or associated lithology. Formally identified lithostratigraphic units are structured in a hierarchy of lithostratigraphic rank, higher rank units generally comprising two or more units of lower rank. Going from smaller to larger in rank, the main lithostratigraphic ranks are Bed, Member, Formation, Group and Supergroup. Formal names of lithostratigraphic units are assigned by geological surveys. Units of formation or hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jasper National Park
Jasper National Park is a national park in Alberta, Canada. It is the largest national park within Alberta's Rocky Mountains spanning . It was established as a national park in 1930 and declared a UNESCO World Heritage Site in 1984. Its location is north of Banff National Park and west of Edmonton. The park contains the glaciers of the Columbia Icefield, springs, lakes, waterfalls and mountains. History First Nations The territory encompassed by what is now Jasper National Park has been inhabited since time immemorial by Nakoda, Cree, Secwépemc, and Dane-zaa peoples. Plainview projectile points have been found at the head of Jasper Lake, dating back to between 8000 and 7000 BCE. In the centuries between then and the establishment of the park, First Nations land use has fluctuated according to climatic variations over the long term, and according to cyclical patterns of ungulate population numbers, particularly elk, moose, mule deer, and occasionally caribou. Starting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, when m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tabulata
Tabulata, commonly known as tabulate corals, are an order of extinct forms of coral. They are almost always colonial, forming colonies of individual hexagonal cells known as corallites defined by a skeleton of calcite, similar in appearance to a honeycomb. Adjacent cells are joined by small pores. Their distinguishing feature is their well-developed horizontal internal partitions (''tabulae'') within each cell, but reduced or absent vertical internal partitions ( ''septa''). They are usually smaller than rugose corals, but vary considerably in shape, from flat to conical to spherical. Around 300 species have been described. Among the most common tabulate corals in the fossil record are ''Aulopora'', ''Favosites'', ''Halysites'', ''Heliolites'', ''Pleurodictyum'', ''Sarcinula'' and '' Syringopora''. Tabulate corals with massive skeletons often contain endobiotic symbionts, such as cornulitids and ''Chaetosalpinx''. Like rugose corals, they lived entirely during the Paleozoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argillaceous Minerals
Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay minerals form in the presence of water and have been important to life, and many theories of abiogenesis involve them. They are important constituents of soils, and have been useful to humans since ancient times in agriculture and manufacturing. Properties Clay is a very fine-grained geologic material that develops plasticity when wet, but becomes hard, brittle and non–plastic upon drying or firing. It is a very common material, and is the oldest known ceramic. Prehistoric humans discovered the useful properties of clay and used it for making pottery. The chemistry of clay, including its capacity to retain nutrient cations such as potassium and ammonium, is important to soil fertility. Because the individual particles in clay are less than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as ''Chlorella,'' ''Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and autotrophic (they generate food internally) and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the ''Charophyta'', a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. No definition of algae is generally accepted. One definition is that algae "have chlorophyll ''a'' as their primary photosynthetic pigment and lack a sterile covering of cells around thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraminifera
Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular Ectoplasm (cell biology), ectoplasm for catching food and other uses; and commonly an external shell (called a "Test (biology), test") of diverse forms and materials. Tests of chitin (found in some simple genera, and Textularia in particular) are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment (i.e., are benthos, benthic), while a smaller number float in the water column at various depths (i.e., are planktonic), which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA. Foraminifera typically produce a test (biology), test, or shell, which can have eithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stromatoporoidea
Stromatoporoidea is an extinct clade of sea sponges common in the fossil record from the Ordovician through the Devonian. They were especially abundant and important reef-formers in the Silurian and most of the Devonian.Stock, C.W. 2001, Stromatoporoidea, 1926–2000: ''Journal of Paleontology'', v. 75, p. 1079–1089. The group was previously thought to be related to the corals and placed in the phylum Cnidaria. They are now classified in the phylum Porifera, specifically the sclerosponges. There are numerous fossil forms with spherical, branching or encrusting skeletons of laminated calcite with vertical ''pillars'' between the ''laminae''. Specimen of its oldest genus, ''Priscastroma'', have been found within the Middle Ordovician Sediments. This same genus has been referred to as the species ''P. gemina'' Khrom., and is known to have been known to branch off into two forms, A and B. Form A gave rise to the genus ''Cystostroma'' while form B gave rise to the genus ''Labechia'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Member (geology)
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features ( facies) that characterize it. Units must be ''mappable'' and ''distinct'' from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%". Lithostratigraphic units Sequences of sedimentary and volcanic rocks are subdivided the basis of their shared or associated lithology. Formally identified lithostratigraphic units are structured in a hierarchy of lithostratigraphic rank, higher rank units generally comprising two or more units of lower rank. Going from smaller to larger in rank, the main lithostratigraphic ranks are Bed, Member, Formation, Group and Supergroup. Formal names of lithostratigraphic units are assigned by geological surveys. Units of formation or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flathead River
The Flathead River ( fla, label=Salish, člq̓etkʷ ntx̣ʷetkʷ, , kut, kananmituk), in the northwestern part of the U.S. state of Montana, originates in the Canadian Rockies to the north of Glacier National Park and flows southwest into Flathead Lake, then after a journey of , empties into the Clark Fork. The river is part of the Columbia River drainage basin, as the Clark Fork is a tributary of the Pend Oreille River, a Columbia River tributary. With a drainage basin extending over and an average discharge of , the Flathead is the largest tributary of the Clark Fork and constitutes over half of its flow. Course The Flathead River rises in forks in the Rocky Mountains of northwestern Montana. The largest tributary is the North Fork, which runs from the Canadian province of British Columbia southwards. The North Fork is sometimes considered the main stem of the Flathead River. Near West Glacier the North Fork combines with the Middle Fork to form the main Flathead River. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock outcrops, etc.—but there are also reefs such as the coral reefs of tropical waters formed by biotic processes dominated by corals and coralline algae, and artificial reefs such as shipwrecks and other anthropogenic underwater structures may occur intentionally or as the result of an accident, and sometimes have a designed role in enhancing the physical complexity of featureless sand bottoms, to attract a more diverse assemblage of organisms. Reefs are often quite near to the surface, but not all definitions require this. Earth's largest coral reef system is the Great Barrier Reef in Australia, at a length of over . Biotic There is a variety of biotic reef types, including oyster reefs and sponge reefs, but the most massive and widely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
