Academic literature on the topic 'Very small glacier'
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Journal articles on the topic "Very small glacier"
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Bahr, D. B., and V. Radić. "Significant contribution to total mass from very small glaciers." Cryosphere 6, no. 4 (July 12, 2012): 763–70. http://dx.doi.org/10.5194/tc-6-763-2012.
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Abstract. A single large glacier can contain tens of millions of times the mass of a small glacier. Nevertheless, very small glaciers (with area ≤1 km2) are so numerous that their contribution to the world's total ice volume is significant and may be a notable source of error if excluded. With current glacier inventories, total global volume errors on the order of 10% are possible. However, to reduce errors to below 1% requires the inclusion of glaciers that are smaller than those recorded in most inventories. At the global scale, 1% accuracy requires a list of all glaciers and ice caps (GIC, exclusive of the ice sheets) larger than 1 km2, and for regional estimates requires a complete list of all glaciers down to the smallest possible size. For this reason, sea-level rise estimates and other total mass and total volume analyses should not omit the world's smallest glaciers. In particular, upscaling GIC inventories has been common practice in sea level estimates, but downscaling may also be necessary to include the smallest glaciers.
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CAPT, M., J. B. BOSSON, M. FISCHER, N. MICHELETTI, and C. LAMBIEL. "Decadal evolution of a very small heavily debris-covered glacier in an Alpine permafrost environment." Journal of Glaciology 62, no. 233 (April 26, 2016): 535–51. http://dx.doi.org/10.1017/jog.2016.56.
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AbstractGlacier response to climate forcing can be heterogeneous and complex, depending on glacier system characteristics. This article presents the decadal evolution of the Tsarmine Glacier (Swiss Alps), a very small and heavily debris-covered cirque glacier located in the Alpine periglacial belt. Archival aerial photogrammetry and autocorrelation of orthophotos were used to compute surface elevation, volume and geodetic mass changes, as well as horizontal displacement rates for several periods between 1967 and 2012. A GPR survey allowed us to investigate glacier thickness (15 m mean) and volume (4 × 106 m3) in 2015 and to anticipate its future evolution. Different dynamics occurred in recent decades because of the heterogeneous surface characteristics. The climate-sensitive upper debris-free zone contrasts with the progressively stagnant heavily debris-covered glacier tongue. Between 1967 and 2012, the glacier lost 1/3 of its initial volume (2 × 106 m3). The average mass balance stabilised at ~−0.3 m w.e. a−1 since 1999. Compared with other local glaciers, the Tsarmine Glacier shows a particular decadal behaviour both in time (divergence of mass balance since the 2000s) and space (inverted ablation pattern). This might be explained by the combined influence of debris cover, shadow, snow redistribution and permafrost conditions on this very small glacier.
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Gachev, Emil M. "Response of Very Small Glaciers to Climate Variations and Change: Examples from the Pirin Mountains, Bulgaria." Atmosphere 13, no. 6 (May 24, 2022): 859. http://dx.doi.org/10.3390/atmos13060859.
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Very small glaciers (glacierets) react strongly to climatic variations. This is well expressed in their interannual size changes, which are most evident in autumn, at the end of the glacial mass balance year. This study presents results from the detailed research of two very small glaciers in the highest northern part of the Pirin Mountains of Bulgaria: Snezhnika and Banski suhodol. Systematic size measurements of these firn-ice bodies, which started in the 1990s and have been made simultaneously for a period of 13 years, show large inter-annual amplitudes against the background of a decreasing trend in response to climate warming. However, the relations are not straightforward, which is demonstrated when comparing size changes to climate data, including logger data obtained from glacier vicinity. This fact makes predictions for the changes in the local climate of high mountain cirques still relatively uncertain.
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Ziaja, Wiesław, Justyna Dudek, and Krzysztof Ostafin. "Landscape transformation under the Gåsbreen glacier recession since 1899, southwestern Spitsbergen." Polish Polar Research 37, no. 2 (June 1, 2016): 155–72. http://dx.doi.org/10.1515/popore-2016-0010.
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Abstract Landscape changes of the Gåsbreen glacier and its vicinity since 1899 are described. Maps at 1:50 000 scale of changes of the glacier’s elevation and extent for the periods 1938–1961, 1961–1990, 1990–2010, and 1938–2010 are analyzed in comparison with results of the authors’ field work in the summer seasons 1983, 1984, 2000, 2005 and 2008. During all the 20th century, the progressive recession of the glacier revealed in a dramatic decrease in the thickness of its lower part, with a small reduction of its area and length. However, further shrinkage produced significant shortening and reduction in area which resulted in final decline of the Goësvatnet glacial dammed lake in 2002. Hence, the lowest (and very thick, up to 150–160 m) part of the former glacier tongue and dammed lake were transformed into a new terraced river valley south of the glacier and a typical marginal zone with glacial landforms north of the glacier. Since 1961, the equilibrium line altitude of the Gåsbreen glacier has risen from ca 350 to ca 500 m a.s.l. and now is located below the very steep rocky walls of the Mehesten mountain ridge, 1378 m a.s.l. Hence, the glacier is being fed by snow avalanches from these rocky walls and much more snow melts during the warmer summer seasons, stimulating a quicker recession of the lowest part of the glacier. This recession may be stopped only by significant climate cooling or increase in snow.
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Van Wyk de Vries, Maximillian, and Andrew D. Wickert. "Glacier Image Velocimetry: an open-source toolbox for easy and rapid calculation of high-resolution glacier velocity fields." Cryosphere 15, no. 4 (April 28, 2021): 2115–32. http://dx.doi.org/10.5194/tc-15-2115-2021.
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Abstract. We present Glacier Image Velocimetry (GIV), an open-source and easy-to-use software toolkit for rapidly calculating high-spatial-resolution glacier velocity fields. Glacier ice velocity fields reveal flow dynamics, ice-flux changes, and (with additional data and modelling) ice thickness. Obtaining glacier velocity measurements over wide areas with field techniques is labour intensive and often associated with safety risks. The recent increased availability of high-resolution, short-repeat-time optical imagery allows us to obtain ice displacement fields using “feature tracking” based on matching persistent irregularities on the ice surface between images and hence, surface velocity over time. GIV is fully parallelized and automatically detects, filters, and extracts velocities from large datasets of images. Through this coupled toolchain and an easy-to-use GUI, GIV can rapidly analyse hundreds to thousands of image pairs on a laptop or desktop computer. We present four example applications of the GIV toolkit in which we complement a glaciology field campaign (Glaciar Perito Moreno, Argentina) and calculate the velocity fields of small mid-latitude (Glacier d'Argentière, France) and tropical glaciers (Volcán Chimborazo, Ecuador), as well as very large glaciers (Vavilov Ice Cap, Russia). Fully commented MATLAB code and a stand-alone app for GIV are available from GitHub and Zenodo (see https://doi.org/10.5281/zenodo.4624831, Van Wyk de Vries, 2021a).
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Barrand, Nicholas E., Robert G. Way, Trevor Bell, and Martin J. Sharp. "Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)." Cryosphere 11, no. 1 (January 24, 2017): 157–68. http://dx.doi.org/10.5194/tc-11-157-2017.
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Abstract. The Torngat Mountains National Park, northern Labrador, Canada, contains more than 120 small glaciers: the only remaining glaciers in continental northeast North America. These small cirque glaciers exist in a unique topo-climatic setting, experiencing temperate maritime summer conditions yet very cold and dry winters, and may provide insights into the deglaciation dynamics of similar small glaciers in temperate mountain settings. Due to their size and remote location, very little information exists regarding the health of these glaciers. Just a single study has been published on the contemporary glaciology of the Torngat Mountains, focusing on net mass balances from 1981 to 1984. This paper addresses the extent to which glaciologically relevant climate variables have changed in northern Labrador in concert with 20th-century Arctic warming, and how these changes have affected Torngat Mountain glaciers. Field surveys and remote-sensing analyses were used to measure regional glacier area loss of 27 % from 1950 to 2005, substantial rates of ice surface thinning (up to 6 m yr−1) and volume losses at Abraham, Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances appear to be controlled by variations in winter precipitation and, increasingly, by strong summer and autumn atmospheric warming since the early 1990s, though further observations are required to fully understand mass balance sensitivities. This study provides the first comprehensive contemporary assessment of Labrador glaciers and will inform both regional impact assessments and syntheses of global glacier mass balance.
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Miles, Evan S., C. Scott Watson, Fanny Brun, Etienne Berthier, Michel Esteves, Duncan J. Quincey, Katie E. Miles, Bryn Hubbard, and Patrick Wagnon. "Glacial and geomorphic effects of a supraglacial lake drainage and outburst event, Everest region, Nepal Himalaya." Cryosphere 12, no. 12 (December 13, 2018): 3891–905. http://dx.doi.org/10.5194/tc-12-3891-2018.
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Abstract. A set of supraglacial ponds filled rapidly between April and July 2017 on Changri Shar Glacier in the Everest region of Nepal, coalescing into a ∼180 000 m2 lake before sudden and complete drainage through Changri Shar and Khumbu glaciers (15–17 July). We use PlanetScope and Pléiades satellite orthoimagery to document the system's evolution over its very short filling period and to assess the glacial and proglacial effects of the outburst flood. We also use high-resolution stereo digital elevation models (DEMs) to complete a detailed analysis of the event's glacial and geomorphic effects. Finally, we use discharge records at a stream gauge 4 km downstream to refine our interpretation of the chronology and magnitude of the outburst. We infer largely subsurface drainage through both of the glaciers located on its flow path, and efficient drainage through the lower portion of Khumbu Glacier. The drainage and subsequent outburst of 1.36±0.19×106 m3 of impounded water had a clear geomorphic impact on glacial and proglacial topography, including deep incision and landsliding along the Changri Nup proglacial stream, the collapse of shallow englacial conduits near the Khumbu terminus and extensive, enhanced bank erosion at least as far as 11 km downstream below Khumbu Glacier. These sudden changes destroyed major trails in three locations, demonstrating the potential hazard that short-lived, relatively small glacial lakes pose.
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Machguth, H., and M. Huss. "The length of the world's glaciers – a new approach for the global calculation of center lines." Cryosphere 8, no. 5 (September 19, 2014): 1741–55. http://dx.doi.org/10.5194/tc-8-1741-2014.
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Abstract. Glacier length is an important measure of glacier geometry. Nevertheless, global glacier inventories are mostly lacking length data. Only recently semi-automated approaches to measure glacier length have been developed and applied regionally. Here we present a first global assessment of glacier length using an automated method that relies on glacier surface slope, distance to the glacier margins and a set of trade-off functions. The method is developed for East Greenland, evaluated for East Greenland as well as for Alaska and eventually applied to all ~ 200 000 glaciers around the globe. The evaluation highlights accurately calculated glacier length where digital elevation model (DEM) quality is high (East Greenland) and limited accuracy on low-quality DEMs (parts of Alaska). Measured length of very small glaciers is subject to a certain level of ambiguity. The global calculation shows that only about 1.5% of all glaciers are longer than 10 km, with Bering Glacier (Alaska/Canada) being the longest glacier in the world at a length of 196 km. Based on the output of our algorithm we derive global and regional area–length scaling laws. Differences among regional scaling parameters appear to be related to characteristics of topography and glacier mass balance. The present study adds glacier length as a key parameter to global glacier inventories. Global and regional scaling laws might prove beneficial in conceptual glacier models.
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Machguth, H., and M. Huss. "The length of the glaciers in the world – a straightforward method for the automated calculation of glacier center lines." Cryosphere Discussions 8, no. 3 (May 14, 2014): 2491–528. http://dx.doi.org/10.5194/tcd-8-2491-2014.
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Abstract. Glacier length is an important measure of glacier geometry but global glacier inventories are mostly lacking length data. Only recently semi-automated approaches to measure glacier length have been developed and applied regionally. Here we present a first global assessment of glacier length using a fully automated method based on glacier surface slope, distance to the glacier margins and a set of trade-off functions. The method is developed for East Greenland, evaluated for the same area as well as for Alaska, and eventually applied to all ∼200 000 glaciers around the globe. The evaluation highlights accurately calculated glacier length where DEM quality is good (East Greenland) and limited precision on low quality DEMs (parts of Alaska). Measured length of very small glaciers is subject to a certain level of ambiguity. The global calculation shows that only about 1.5% of all glaciers are longer than 10 km with Bering Glacier (Alaska/Canada) being the longest glacier in the world at a length of 196 km. Based on model output we derive global and regional area-length scaling laws. Differences among regional scaling parameters appear to be related to characteristics of topography and glacier mass balance. The present study adds glacier length as a central parameter to global glacier inventories. Global and regional scaling laws might proof beneficial in conceptual glacier models.
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Knight, Peter G. "Ice deformation very close to the ice-sheet margin in West Greenland." Journal of Glaciology 38, no. 128 (1992): 3–8. http://dx.doi.org/10.1017/s0022143000009539.
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AbstractThis paper describes fine-resolution measurements of glacier surface strain rates very close to the margin of Russell Glacier, West Greenland. Measurements at a small scale make possible detailed analysis of strain patterns close to the glacier margin, and suggest that strain rates vary over small areas. The strain pattern is determined by ice flexure over subglacial obstacles as well as by seasonally variable marginal retardation and by the orientation of the ice margin relative to the flow direction.
Book chapters on the topic "Very small glacier"
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Narama, Chiyuki, and Kenshiro Arie. "Glaciology: Mass Balance of Very Small Glaciers on Mount Kenya During 2016–2018." In Glaciers, Nature, Water, and Local Community in Mount Kenya, 1–14. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7853-0_1.
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Taillant, Jorge Daniel. "The Birth of Cryoactivism." In Glaciers. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780199367252.003.0008.
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Juan Pablo Milana and the environmentalists of San Juan Province left a memorable impression in the mind of Argentina’s Environment Secretary, Romina Picolotti. But she realized that fighting a glacier protection battle against the very well entrenched mining industry could be a defining con¬frontation for her tenure as Secretary. If she lost the battle, it would mean her inevitable resignation as head of the agency. In her short time inside politics, she had already learned to pick her battles carefully because the political stakes were always at the highest level. The loss of any battle, however small, could be the end of her political favor with President Nestor Kirchner. And, in her case, because she was a public figure brought to the administration on technical expertise and not because of any political track, that would probably mean the end of her political career. Environment was not a priority issue for Argentina, although, as in many parts of the world, it was slowly gaining social recognition and consequently political force (these generally come in that order). As such, any politically unmanageable problem from the low-profile Environment Secretariat could mean unnecessary and unwanted political conflict for the executive branch. It would not be tolerated. Furthermore, both the president and his eventual successor Cristina Fernandez, for whom Picolotti would continue as Environment Secretary, were from prov¬inces heavily entrenched in industry—the extractive oil and gas industry—and their outlook on development was mostly aligned with and tied to the oil sec¬tor. They believed that large tracts of land without industry and development (of which Argentina has many) is land gone to waste. One preposterous plan to emerge in their home province of Santa Cruz, site of Argentina’s Glacier National Park, was to build a massive dam (Condor Cliff Dam, renamed the Nestor Kirchner Dam) by flooding a large glacier lake (Lago Argentino) well above its natural water line to harness hydrological power for downstream communities. This would flood and disturb numerous glaciosystems.But Nestor Kirchner had confided to Picolotti when he first brought her to his administration as Environment Secretary that his generation did not understand environmental issues.
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Furbish, David Jon. "Introduction." In Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0005.
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Fluids are involved in virtually all geological processes. Obvious examples are phenomena occurring at Earth’s surface in which fluid flow is a highlight: the flow of a lava stream, the play of a geyser, river flow and wind currents, the swash and backswash on a beach. Also obvious are phenomena that occur in the presence of fluid flows, such as sediment motion. Less obvious, but readily imaginable in terms of their behaviors, are fluid motions occurring within Earth’s crust: flows of magma and ground water, and expulsion of brines from sediments during compaction. In addition, a bit of reflection will recall a host of phenomena in which fluid behavior, although not the highlight, may nonetheless take on a significant role: initiation of landslides, seismic activity, glacier movement, taphonomic organization, and fracture mechanics. With these should be considered instances in which the geological material containing a fluid can influence its fundamental behavior at a molecular scale. An example is flow through very small rock pores, where molecular forces interacting among fluid molecules and pore surfaces can lead to a structural arrangement of the fluid molecules such that their mechanical behavior is unlike that which occurs in large pores, where the bulk of the fluid is “far” from pore surfaces. It is thus understandable that to describe many geologic phenomena requires knowing how fluids work. It is also natural to begin by considering how fluids behave in a general way, then in turn, how they are involved in specific geological processes. There are several approaches for describing fluids and their motions, and the choice of one, or some combination, depends on the sort of insight desired as well as the specific problem being considered. Fluid statics, as the name implies, involves considering the properties of fluids that are at rest in some inertial frame of reference. Note that this frame of reference may actually be moving relative to the Earth frame of reference, so long as the fluid motion is like that of a rigid body. An important example of our use of fluid statics will be in developing the hydrostatic equation, which formalizes how fluid pressure varies with depth.
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Yalden, D. W. "Zoological Perspectives on the Late Glacial." In Palaeolithic Cave Art at Creswell Crags in European Context. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780199299171.003.0010.
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Enough mammal specimens of Late Glacial date from the British Isles have been subjected to radiocarbon dating to provide a reliable outline of the likely large mammal fauna of the time, though the accompanying fauna of small mammals has mostly been assigned to this period on associative, rather than direct, dating. These give an adequate zoological background against which to examine the suggested identities of the large mammals depicted at Church Hole, Creswell Crags. This background information is reviewed in this chapter. While Bison priscus was certainly present earlier in the Devensian, there is no evidence that Bison returned to Britain in the Late Glacial, but aurochs (Bos primigenius) did so, and must be considered a more probable identification. The evidence that ibex (Capra ibex) ever occurred in Britain is very dubious, which cast serious doubt on the original identification of the Church Hole Panel III engraving as being of this species. In this case, discussion and reinterpretation of the engravings during the course of the conference suggested a better resolution than the zoological one suggested at the time. The ice of the Devensian glacial maximum, at about 20–18 ka BP, is believed to have covered all of northern Great Britain and Ireland, leaving smaller areas of the south of each island free of ice but occupied by tundra, permafrost, conditions. It is most unlikely that any of the present mammal fauna could have survived here then, though the possibilities that mountain hare (Lepus timidus) and stoat (Mustela erminea) did so must be conceded—both range well into the Arctic at the present day. The severity of the climate, and the likely nature of the mammal fauna, is indicated by the presence of musk ox (Ovibos moschatus) (Fisherton, Wiltshire, but undated) and the possible polar bear (Ursus maritimus) (Creag nan Uamh, Sutherland, 18.9 ka: Kitchener and Bonsall 1997) that date to this time. Barnwell Station, Cambridge, has a<sup>14</sup> C date on peat of 19.5 ka BP, and a fauna including woolly mammoth (Mammuthus primigenius), woolly rhinoceros (Coelodonta antiquitatis), reindeer (Rangifer tarandus), and horse (Equus ferus). Dated specimens fromsouthern Ireland are also relevant: collared lemming (Dicrostonyx torquatus) at20.3 ka BP, woolly mammoth at 20.36 ka BP and Arctic fox (Alopex lagopus) at 19.95 ka BP, all from Castlepook Cave, Cork (Woodman et al. 1997).
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Koster, Eduard, and Tim Favier. "Peatlands, Past and Present." In The Physical Geography of Western Europe. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780199277759.003.0018.
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Peatlands are fascinating wetland ecosystems. They provide a habitat for a wide range of highly adapted plant and animal species. In addition to the floristic and ornithological richness, peatlands have been recognized for many other values. For instance, drained peatland soils often have good agricultural properties, and peat has been and still is in some places extensively used as fuel. In coastal wetlands peat has even been used for salt extraction. Furthermore, peat is an interesting material for science, as it contains information on the palaeoecological environment, climate change, carbon history, and archaeology. In north-western Europe, peatlands were once quite extensive, covering tens of thousands of square kilometres. However, most of them have been strongly exploited by humans during past centuries. Many peatlands have been cultivated for agriculture and forestry, or have been exploited by commercial or domestic peat extraction for fuel. As a result, only a very small part of north-western Europe’s peatlands remains today in a more or less natural state. This chapter focuses on the peat deposits and peatlands in north-western Europe that have formed since the Late Glacial (c.13 ka BP). First, the most common concepts in peatland terminology are explained, and the distribution of peatlands is described. Next, processes of peat formation and the relationship between peatforming processes and climate, hydrology, vegetation, and other factors are discussed. In the following section, frequently used classification methods are presented. A historical overview of the cultivation and exploitation of peatlands is given and the present land use and characteristics of peatland soils are discussed. The following section deals with methods of conservation and rehabilitation of the remaining mires. The importance of peatlands as palaeoecological archives is examplified. Finally, the role of peatlands as a source and/or sink of CO2 and the relations with climate change are briefly explained. Peat is the unconsolidated material that predominantly consists of slightly decomposed or undecomposed organic material in which the original cellular and tissue structures can often be identified. Peat forms in lakes and mires under waterlogged, anaerobic conditions.
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Wasilewski, Michał. "Rozpoznanie petrograficzne i analiza geoarcheologiczna kamiennych zabytków ruchomych z cmentarzyska w Świbiu / Petrographic identification and geoarchaeological analysis of lithic portable artefacts from the cemetery at Świbie." In Cmentarzysko w wczesnej epoki żelaza w Świbiu na Górnym Śląsku. Tom 2, 350–54. Wydawnictwo Profil-Archeo, 2022. http://dx.doi.org/10.33547/swibie2022.2.17.
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The site of Świbie 16 is located near the border of two very important physiographic units: the Silesia Upland Macroregion and the Silesia Lowland Macroregion (Kondracki 2002; Solon et al. 2018; Richling et al. 2021). Such a location offered good access to the rocks abundant in the former macroregion and the rivers and arable lands in the latter. Geologically, the discussed site lies within the Krakow-Częstochowa monocline. The identification of raw materials was carried out using macroscopic methods only, using Brinell magnifiers with 10x and 20x magnification, hydrochloric acid (HCl 5%), and the Munsell scale. Middle Triassic rocks occur in the direct subsoil of the Świbie 16 site. They occur as Muschelkalk (Lower Gogolin Beds) and limestones and marls (Upper Gogolin Beds). Small quarries of these rocks operated within a radius of 10 km from the site. Within a radius of 15-20 km from Świbie 16, outcrops of other rocks can also be found: Lower Carboniferous beds (Visean; in the form of greywacke sandstones, shales and mudstones), Lower Triassic (Induan-Olenekian; sands, motley (red) sandstones, clays, claystones and mudstones), Middle Triassic (Anisian, the so-called Jemielnica Beds, formed as dolomites), Upper Triassic (Keuper (=Carnian-Norian)), the Lisowskie beds (occurring, among others, as laminated, motley claystones of various colors, including yellow-aquamarine and green), and Lower Jurassic. Younger sediments are represented by glacial, fluvioglacial and fluvial sediments (clays, sands, gravels and even boulders). These formations contain both pebbles of the bedrock and Scandinavian rocks. In the immediate vicinity there are also sites of alluvium, lake silts with chalk, and peats, which are the remains of a Holocene water reservoir. The origin of the Muschelkalk objects found in graves 275 and 286 is least in doubt. However, their interpretation as artefacts should be approached with caution, because no obvious traces of processing were noticed during their examination. Four items (an axe, a polisher, a whetstone, and a geofact) were made from sandstone. In all of them, the raw material is very similar petrographically, and its source should be sought in the Lower Triassic rocks or fluvial gravels occurring south of Świbie. In grave 16, an axe made of amphibolite was found. This rock probably comes from fluvioglacial deposits. Two objects (an axe and a disc with a hole) were made of greenish shales. Similar shales and claystones come from the Lisowskie beds, which occur not far north of the site. The three quartz pebbles analysed are typical, natural components of Quaternary fluvial or fluvioglacial gravels and are not particularly interesting for geoarchaeological analyses. The presented geographical, geological and lithological context, in confrontation with the results of the macroscopic petrographic analysis of lithic artefacts from the Świbie 16 site, allows us to conclude that the raw materials used for their production are of local provenance. They most likely come from a distance of no more than 10–15 km from the site.
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"Landscape Influences on Stream Habitats and Biological Assemblages." In Landscape Influences on Stream Habitats and Biological Assemblages, edited by Christopher W. Hoagstrom and Charles R. Berry. American Fisheries Society, 2006. http://dx.doi.org/10.47886/9781888569766.ch11.
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<em>Abstract.</em>—We reviewed native fish zoogeography in 22 major tributary basins of the Missouri River basin in the Great Plains geomorphic province and used island biogeographical approaches to study the influence of basin area and isolation on faunal composition. Basin area was correlated with elevation range and basin isolation was negatively correlated with annual freeze-free days. Ninety-six species were native to the tributary basins. Ninety-one were of southern (Gulf of Mexico drainage) origin. Fifty were found in four or fewer tributary basins and, except for three mountain species, were only found from the Cheyenne basin downstream. Twenty-five widespread species were either present among tributary basins during glaciation or colonized the region during recession of the continental glaciers. Sixty-six more restricted species presumably colonized more recently. Five species colonized from Pacific Ocean drainages via interdrainage connections in the Rocky Mountains. The hypothesis that variation between some closely related Great Plains fishes reflects the former presence of a prehistoric “Ancient Plains Drainage” is no longer tenable given recent geological findings, but a series of stream captures between the ancient Arkansas and Kansas basins could account for such variation. All analyses indicated that native fish faunal composition among tributary basins was heavily influenced by factors related to basin area and isolation. A presence–absence matrix of fishes by tributary basin had very high nestedness, whether ordered by basin area or basin isolation. Cluster analysis of Wilcoxon two-sample tests of individual species distributions revealed seven species groups with distinct distribution patterns. The three largest groups were most prevalent in less isolated (southern) tributary basins. A nonmetric multidimensional scaling analysis (NMDS) based on Sørensen’s index of similarity indicated that two axes (both correlated with tributary basin isolation, one correlated with tributary basin area) accounted for 95% of variance between distance in the ordination space and distance in the original <em>n</em>-dimensional space. A cluster analysis of NMDS scores identified five tributary basin groups. The five southernmost basins (Kansas to White) composed one group, and the eight basins to the north (Bad to Little Missouri) composed another. The nine northernmost basins were split into three groups, one including small basins isolated from the Rocky Mountains, another including large basins with Rocky Mountain headwaters, and the last including two basins that were mostly within the Rocky Mountains. The influence of tributary basin area on faunal composition was presumably due to increased chance of colonization, higher habitat stability, and higher habitat diversity in larger tributary basins. The influence of tributary basin isolation was presumably due to higher colonization rates and more equitable climate in southern tributary basins. Fish faunas of the Missouri River basin in the Great Plains have experienced cyclical geomorphic and climatic instability for roughly 2.8 million years and were assembled like island faunas by variable colonization and extinction rates mediated by tributary basin area and isolation. This contrasts with the highly diverse freshwater fish faunas of the Central Highlands that have differentiated through speciation within regions that have been relatively stable geomorphically and climatically for more than 38 million years.