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Imbrication (sedimentology)
In sedimentology, imbrication is a primary depositional Fabric (geology), fabric consisting of a preferred orientation of clasts such that they overlap one another in a consistent fashion, rather like a run of toppled dominoes. Imbrication is observed in Conglomerate (geology), conglomerates and in some volcaniclastic deposits. Types : In conglomerates the shape of many clasts can be approximated to an ellipsoid, with a long axis (A), an intermediate axis (B) and a short axis (C). * ''A-axis imbrication'' where the long axes of the clasts are oriented parallel to the flow direction. This fabric is characteristic of clasts carried in suspension and this is only preserved in the case of a fast-waning flow in which the clasts are deposited without any significant rolling. This fabric is typical of conglomerates at the base of turbidite beds but is also occasionally observed in alluvial fan deposits reworked by flash floods * ''AB-plane imbrication'' where the long axes of the clast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imbricated Fabric
wikt:imbrication, Imbrication is the arrangement of planar bodies such that they stack in a consistent fashion - rather like a toppled run of dominoes. *In roofing, imbrication is employed in the Imbrex and tegula system. *Imbrication (sedimentology). *Imbrication (linguistics), a morphophonological phenomenon {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imbricated Fabric Overlay
Imbrication is the arrangement of planar bodies such that they stack in a consistent fashion - rather like a toppled run of dominoes. *In roofing, imbrication is employed in the Imbrex and tegula system. *Imbrication (sedimentology) In sedimentology, imbrication is a primary depositional Fabric (geology), fabric consisting of a preferred orientation of clasts such that they overlap one another in a consistent fashion, rather like a run of toppled dominoes. Imbrication is ob .... * Imbrication (linguistics), a morphophonological phenomenon {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentology
Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation (erosion and weathering), transport, deposition and diagenesis. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures. Sedimentary rocks cover up to 75% of the Earth's surface, record much of the Earth's history, and harbor the fossil record. Sedimentology is closely linked to stratigraphy, the study of the physical and temporal relationships between rock layers or strata. The premise that the processes affecting the earth today are the same as in the past is the basis for determining how sedimentary features in the rock record were formed. By comparing similar features today to features in the rock record—for example, by comparing modern sand dunes to dunes preserved in ancient aeolian sandstones—geologists reconstruct past environm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fabric (geology)
In geology, a rock's fabric describes the spatial and geometric configuration of all the elements that make it up. In sedimentary rocks, the fabric developed depends on the depositional environment and can provide information on current directions at the time of deposition. In structural geology, fabrics may provide information on both the orientation and magnitude of the strains that have affected a particular piece of deformed rock. Types of fabric * Primary fabric — a fabric created during the original formation of the rock, e.g. a preferred orientation of clast long axes in a conglomerate, parallel to the flow direction, deposited by a fast waning current. * Shape fabric — a fabric that is defined by the preferred orientation of inequant elements within the rock, such as platy- or needle-like mineral grains. It may also be formed by the deformation of originally equant elements such as mineral grains. * Crystallographic preferred orientation — in plastically defo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clast
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conglomerate (geology)
Conglomerate () is a sedimentary rock made up of rounded gravel-sized pieces of rock surrounded by finer-grained sediments (such as sand, silt, or clay). The larger fragments within conglomerate are called clasts, while the finer sediment surrounding the clasts is called the matrix. The clasts and matrix are typically cemented by calcium carbonate, iron oxide, silica, or hardened clay. Conglomerates form when rounded gravels deposited by water or glaciers become solidified and cemented by pressure over time. They can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of all sedimentary rocks. They are closely related to sandstones in origin, and exhibit many of the same types of sedimentary structures, such as tabular and trough cross-bedding and graded bedding.Boggs, S. (2006) ''Principles of Sedimentology and Stratigraphy.'', 2nd ed. Prentice Hall, New York. 662 pp. Friedman, G.M. (2003) ''Classification of sediments and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcaniclastic
Volcaniclastics are geologic materials composed of broken fragments (clasts) of volcanic rock. These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it was deposited in, or whether nonvolcanic material is mingled with the volcanic clasts. The United States Geological Survey defines volcaniclastics somewhat more narrowly, to include only rock composed of volcanic rock fragments that have been transported some distance from their place of origin. In the broad sense of the term, volcaniclastics includes pyroclastic rocks such as the Bandelier Tuff; cinder cones and other tephra deposits; the basal and capping breccia that characterize ʻaʻā lava flows; and lahars and debris flows of volcanic origin.Vincent 2000, pp.27-28 Volcaniclastics make up more of the volume of many volcanoes than do lava flows. Volcaniclastics may have contributed as much as a third of all sedimentation in the geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis J
Francis may refer to: People and characters *Pope Francis, head of the Catholic Church (2013–2025) *Francis (given name), including a list of people and fictional characters * Francis (surname) * Francis, a character played by YouTuber Boogie2988 Places * Rural Municipality of Francis No. 127, Saskatchewan, Canada * Francis, Saskatchewan, Canada ** Francis (electoral district) * Francis, Nebraska, USA * Francis Township, Holt County, Nebraska, USA * Francis, Oklahoma, USA * Francis, Utah, USA Arts, entertainment, media * ''Francis'' (film), the first of a series of comedies featuring Francis the Talking Mule, voiced by Chill Wills *''Francis'', a 1983 play by Julian Mitchell * Francis (band), a Sweden-based folk band *Francis (TV series), a Indian Bengali-language animated television series Other uses *FRANCIS, a bibliographic database * ''Francis'' (1793), a colonial schooner in Australia *Francis turbine, a type of water turbine See also * Saint Francis (other) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbidite
A turbidite is the geologic Deposition (geology), 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 Conglomerate (geology), 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 sequence, 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; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alluvial Fan
An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiarid climates, but are also found in more humid environments subject to intense rainfall and in areas of modern glaciation. They range in area from less than to almost . Alluvial fans typically form where a flow of sediment or rocks emerge from a confined channel and are suddenly free to spread out in many directions. For example, many alluvial fans form when steep mountain valleys meet a flat plain. The transition from a narrow channel to a wide open area reduces the carrying capacity of flow and results in Deposition (geology), deposition of sediments. The flow can take the form of infrequent debris flows like in a landslide, or can be carried by an intermittent stream or creek. The reduction of flow is key to the formation of alluvial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedload
The term bed load or bedload describes particles in a flowing fluid (usually water) that are transported along the stream bed. Bed load is complementary to suspended load and wash load. Bed load moves by rolling, sliding, and/or saltating (hopping). Generally, bed load downstream will be smaller and more rounded than bed load upstream (a process known as downstream fining). This is due in part to attrition and abrasion which results from the stones colliding with each other and against the river channel, thus removing the rough texture (rounding) and reducing the size of the particles. However, selective transport of sediments also plays a role in relation to downstream fining: smaller-than average particles are more easily entrained than larger-than average particles, since the shear stress required to entrain a grain is linearly proportional to the diameter of the grain. However, the degree of size selectivity is restricted by the hiding effect described by Parker and K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geografiska Annaler
''Geografiska Annaler'' is a scientific journal published by the Swedish Society for Anthropology and Geography in Stockholm, Sweden. The journal is founded in 1919. Since 1965 the journal is published in two series A and B. Series A deals with arctic research, physical geography, glaciology and quaternary science in general. Series B covers the topics of human geography Human geography or anthropogeography is the branch of geography which studies spatial relationships between human communities, cultures, economies, and their interactions with the environment, examples of which include urban sprawl and urban ... and economic geography, with a special, but not exclusive, focus on the Nordic and Baltic countries. References 1919 establishments in Sweden Geography journals Geology journals Glaciology journals Quaternary science journals Magazines published in Stockholm Academic journals established in 1919 Quarterly journals {{sweden-mag-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
