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Lock Haven Formation
The Lock Haven Formation is a Devonian mapped bedrock unit in Pennsylvania, in the Appalachian Mountains of the United States. Description The Lock Haven is gray to green-brown sandstone, siltstone, and shale and is over 400 million years old. It is located in northcentral Pennsylvania. Stratigraphy The Lock Haven may underlie various members of the Catskill Formation, although it may be a lateral equivalent of the Sherman Creek or Irish Valley Members of the Catskill. It is also a lateral equivalent of the Foreknobs Formation and underlying Scherr Formation. The Brallier Formation usually underlies the Lock Haven. The Minnehaha Springs Member (originally proposed as a member of the Scherr Formation) is a " clastic bundle" consisting of interbedded medium gray siltstone and olive gray shale with some grayish-red siltstone and shale and some sandstone. It is interpreted as turbidites. This member is proposed to define the base of the Lock Haven Formation. Notable Exposu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clastic
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks by physical weathering.Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-5 Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport, whether in suspension or as bed load, and in sediment deposits. Sedimentary clastic rocks Clastic sedimentary rocks are rocks composed predominantly of broken pieces or ''clasts'' of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material (matrix) composition, and texture. The classification factors are often useful in determining a sample's environment of deposition. An example of clastic environment would be a river system in which the full range of grains being transported by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Pennsylvania
The Geology of Pennsylvania consists of six distinct physiographic provinces, three of which are subdivided into different sections. Each province has its own economic advantages and geologic hazards and plays an important role in shaping everyday life in the state. They are: (listed from the southeast corner to the northwest corner) the Atlantic Coastal Plain Province, the Piedmont Province, the New England Province, the Ridge and Valley Province, the Appalachian Plateau Province, and the Central Lowlands Province. A majority of the rocks in Pennsylvania exposed at the surface are sedimentary and were deposited during the Paleozoic Era. Almost all of the metamorphic and igneous rocks are confined to the southeast portion of the state. A total of four orogenies have affected the rocks of the Commonwealth including the Grenville orogeny, the Taconic orogeny, the Acadian orogeny, and the Appalachian orogeny. The Appalachian event has left the most evidence and has continued to sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizocorallium
''Rhizocorallium'' is an ichnogenus of burrow, the inclination of which is typically within 10° of the bedding planes of the sediment. These burrows can be very large, over a meter long in sediments that show good preservation, e.g. Jurassic rocks of the Yorkshire Coast (eastern United Kingdom), but the width is usually only up to 2 cm, restricted by the size of the organisms producing it. It is thought that they represent fodinichnia as the animal (probably a polychaete) scoured the sediment for food. Ichnogenus The ichnogenus ''Rhizocorallium'' Zenker 1836 includes three ichnospecies: ''Rhizocorallium jenense'' Zenker 1836 representing straight, short U-shaped spreite Spreite, meaning Lamina (leaf), leaf-blade in German (or spreiten, the plural form in German language, German) is a stacked, curved, layered structure that is characteristic of certain trace fossils. They are formed by invertebrate organisms tunn ...-burrows commonly oblique to bedding plane, and only rare ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arenicolites
''Arenicolites'' is a U-shaped ichnotaxon (trace fossil) dating from Ediacaran times onwards in South Australia. The trace shown by this fossil, is a pair of closely spaced circles on a bedding plane In geology, a bed is a layer of sediment, sedimentary rock, or pyroclastic material "bounded above and below by more or less well-defined bedding surfaces".Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds., 2005. ''Glossary of Geology'' .... In vertical section the traces are U or J shaped. They appear to be burrows made by a kind of worm. References Trace fossils Ediacaran life {{trace-fossil-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cruziana
''Cruziana'' is a trace fossil consisting of elongate, bilobed, approximately bilaterally symmetrical burrows, usually preserved along bedding planes, with a sculpture of repeated striations that are mostly oblique to the long dimension. It is found in marine and freshwater sediments. It first appears in upper Fortunian rocks of northern Iran and northern Norway. ''Cruziana'' has been extensively studied because it has uses in biostratigraphy (specific scratch patterns are unique to specific time intervals), and because the traces can reveal many aspects of their makers' behavior. ''Cruziana'' is typically associated with trilobites but can also made by other arthropods. ''Cruziana'' appears in non-marine formations such as the Beacon Supergroup that would have been unsuitable environments for trilobites, and in Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brachiopods
Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, while the front can be opened for feeding or closed for protection. Two major categories are traditionally recognized, articulate and inarticulate brachiopods. The word "articulate" is used to describe the tooth-and-groove structures of the valve-hinge which is present in the articulate group, and absent from the inarticulate group. This is the leading diagnostic skeletal feature, by which the two main groups can be readily distinguished as fossils. Articulate brachiopods have toothed hinges and simple, vertically-oriented opening and closing muscles. Conversely, inarticulate brachiopods have weak, untoothed hinges and a more complex system of vertical and oblique (diagonal) muscles used to keep the two valves aligned. In many brachiopods, a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sullivan County, Pennsylvania
Sullivan County is a county in the Commonwealth of Pennsylvania. It is part of Northeastern Pennsylvania. As of the 2020 census, the population was 5,840, making it the second-least populous county in Pennsylvania. Its county seat is Laporte. The county was created on March 15, 1847, from part of Lycoming County and named for Major General John Sullivan History The land which became Sullivan County was originally purchased from the Iroquois by the Province of Pennsylvania in 1768, as part of the first Treaty of Fort Stanwix. It was then part of Northumberland County, then became part of Lycoming County when it was formed in 1795. Sullivan County itself was formed from the northeastern part of Lycoming County on March 15, 1847. It was the thirteenth and last county formed at least partly from Lycoming County (and the fifth entirely formed from it). Sullivan County was named for Pennsylvania state senator Charles C. Sullivan, who "took an active part in procuring passage of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forksville, Pennsylvania
Forksville is a List of municipalities in Sullivan County, Pennsylvania, borough in Sullivan County, Pennsylvania, United States. The population was 110 at the 2020 census. It is the home of the 150-year-old Forksville General Store, down the road from the Sullivan County Fairgrounds, and near Worlds End State Park. The name comes from the confluence of Little Loyalsock Creek and Loyalsock Creek within the borough. History The Forksville Covered Bridge was added to the National Register of Historic Places in 1980. Forksville was first permanently settled by William Molyneaux, John Warren and Powell Bird. A sawmill was built in the Forksville area in 1810. Forksville was formed from Forks Township, Sullivan County, Pennsylvania, Forks Township in 1880. Geography According to the United States Census Bureau, the borough has a total area of , all land. Demographics At the 2010 United States Census, 2010 census, there were 145 people, 67 households, and 42 families residing in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pine Creek Gorge
Pine Creek Gorge, sometimes called The Grand Canyon of Pennsylvania, is a gorge carved into the Allegheny Plateau by Pine Creek in north-central Pennsylvania. It sits in about of the Tioga State Forest. The canyon begins south of Ansonia, near Wellsboro, along U.S. Route 6 and continues south. Its deepest point is at Waterville, near the southern end. At Leonard Harrison and Colton Point State Parks, it is more than deep and the distance rim-to-rim is about . Formation Pine Creek had flowed northeasterly until about 20,000 years ago, when the receding Laurentide Continental Glacier dammed it with rocks, soil, and other debris. Glacial meltwater formed a lake near the present town of Ansonia, and when it overflowed the debris dam, the creek flooded to the south. Ultimately, it carved a deep channel on its way south to the West Branch Susquehanna River. Protected areas The Pine Creek Gorge National Natural Landmark includes Colton Point and Leonard Harrison State Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbidite
A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing Turbidites were first properly described by Arnold H. Bouma (1962), who studied deepwater sediments and recognized particular "fining-up intervals" within deep water, fine-grained shales, which were anomalous because they started at pebble conglomerates and terminated in shales. This was anomalous because within the deep ocean it had historically been assumed that there was no mechanism by which tractional flow could carry and deposit coarse-grained sediments into the abyssal depths. Bouma cycles begin with an erosional contact of a coarse lower bed of pebble to granule conglomerate in a sandy matrix, and grade up through coarse then medium plane parallel sandstone; through cross-bedded sandstone; rippled cross-bedded sand/silty sand, and finally lami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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