scholarly journals Development of a surface roughness curve to estimate timing of earthflows and habitat development in the Teanaway River, central Washington State, USA

2021 ◽  
Author(s):  
Sarah Anne Schanz ◽  
Armistead Peyton Colee
Keyword(s):  
Surface Roughness ◽  
Late Holocene ◽  
Fine Sediment ◽  
Cascade Range ◽  
Mass Movements ◽  
Fine Grained ◽  
Morphologic Characteristics ◽  
Slow Moving ◽  
Wet Climate ◽  
Habitat Development

Abstract. Salmon habitat is enhanced by the wide valleys and channel heterogeneity created by landslides. Earthflows, which are slow moving and fine-grained mass movements, can further potentially alter habitat by constricting valleys and sustaining delivery of debris and fine sediment. Here, we examine the influence of earthflows on salmon habitat in the Teanaway River basin, central Cascade Range, Washington. We mapped earthflows based on morphologic characteristics and relatively dated earthflow activity using a flow directional surface roughness metric called MADstd. The relative MADstd ages are supported by six radiocarbon ages, three lake sedimentation ages, and 20 cross-cutting relationships, indicating that MADstd is a useful tool to identify and relatively date earthflows, especially in heavily vegetated regions. Our age and MADstd distributions reflect a period of earthflow activity in the mid-Holocene and some sustained movement through the late Holocene that is primed by regolith production in the Pleistocene and early Holocene and triggered by a warm and wet climate during the mid-Holocene. The timing of earthflows is coincident with stabilization of salmon habitat and abundant salmon populations, indicating the fine sediment from earthflows did not negatively impact habitat. Wide valleys formed upstream of valley-constricting earthflows have added habitat zones, which may be of increased importance as climate change causes lower flows and higher temperatures in the Teanaway basin over the next century.

Surface and Sub-Surface Integrity of Ultra- Machined BK7 Using Fine and Coarse Grained Diamond Wheels

2007 ◽  
Vol 359-360 ◽  
pp. 234-238 ◽  
Author(s):  
Qing Liang Zhao ◽  
Bo Wang ◽  
Ekkard Brinksmeier ◽  
Otmann Riemer ◽  
Kai Rickens ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
High Surface ◽  
Coarse Grained ◽  
Nanometer Scale ◽  
Grinding Wheels ◽  
Fine Grained ◽  
Optical Glasses ◽  
Diamond Grinding ◽  
Surface Damages

This paper aims to evaluate the surface and sub-surface integrity of optical glasses which were correspondingly machined by coarse and fine-grained diamond grinding wheels on Tetraform ‘C’ and Nanotech 500FG. The experimental results show that coarse-grained diamond grinding wheels are capable of ductile grinding of optical glasses with high surface and sub-surface integrity. The surface roughness values are all in nanometer scale and the sub-surface damages are around several micros in depth, which is comparative to those machined by fine-grained diamond wheels.

Paleoecological implications of the first prehistoric record of water vole (Microtus richardsoni) from Washington state, USA

2019 ◽  
Vol 92 (2) ◽  
pp. 381-387
Author(s):  
R. Lee Lyman
Keyword(s):  
Late Holocene ◽  
Sampling Error ◽  
Archaeological Site ◽  
Cascade Range ◽  
Western Montana ◽  
Water Vole ◽  
Long Distance ◽  
The North ◽  
Long Distance Transport ◽  
Distance Transport

AbstractRemains of the North American water vole (Microtus richardsoni) have previously been recovered from late Pleistocene and Holocene deposits in southwestern Alberta, western Montana, and north-central Wyoming. All are within the historically documented modern range of the metapopulation occupying the Rocky Mountains; no ancient remains of this large microtine have previously been reported from the metapopulation occupying the Cascade Range. Four lower first molar specimens from the late Holocene Stemilt Creek Village archaeological site in central Washington here identified as water vole are from the eastern slope of the Cascade Range and are extralimital to the metapopulation found in those mountains. There is no taphonomic evidence indicating long-distance transport of the teeth, and modern trapping records suggest the local absence of water voles from the site area today is not a function of sampling error. The precise age of the Stemilt Creek Village water voles is obscure but climate change producing well-documented late Holocene advances of nearby alpine glaciers could have created habitat conditions conducive to the apparent modest shift in the range of the species represented by the remains.

scholarly journals Mechanical properties of NiTi and CuNiTi wires used in orthodontic treatment. Part 2: Microscopic surface appraisal and metallurgical characteristics

2014 ◽  
Vol 19 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Marco Abdo Gravina ◽  
Cristiane Canavarro ◽  
Carlos Nelson Elias ◽  
Maria das Graças Afonso Miranda Chaves ◽  
Ione Helena Vieira Portella Brunharo ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Test Methods ◽  
Chemical Compositions ◽  
Wire Surface ◽  
Morphologic Characteristics ◽  
Fracture Region ◽  
Traction Test ◽  
Niti Wires ◽  
Electronic Microscope

OBJECTIVE: This research aimed at comparing the qualitative chemical compositions and the surface morphology of fracture regions of eight types of Nickel (Ni) Titanium (Ti) conventional wires, superelastic and heat-activated (GAC, TP, Ormco, Masel, Morelli and Unitek), to the wires with addition of copper (CuNiTi 27oC and 35oC, Ormco) after traction test. METHODS: The analyses were performed in a scanning electronic microscope (JEOL, model JSM-5800 LV) with EDS system of microanalysis (energy dispersive spectroscopy). RESULTS : The results showed that NiTi wires presented Ni and Ti as the main elements of the alloy with minimum differences in their composition. The CuNiTi wires, however, presented Ni and Ti with a significant percentage of copper (Cu). As for surface morphology, the wires that presented the lowest wire-surface roughness were the superelastic ones by Masel and Morelli, while those that presented the greatest wire-surface roughness were the CuNiTi 27oC and 35oC ones by Ormco, due to presence of microcavity formed as a result of pulling out some particles, possibly of NiTi. 4 The fracture surfaces presented characteristics of ductile fracture, with presence of microcavities. The superelastic wires by GAC and the CuNiTi 27oC and the heat-activated ones by Unitek presented the smallest microcavities and the lowest wire-surface roughness with regard to fracture, while the CuNiTi 35oC wires presented inadequate wire-surface roughness in the fracture region. CONCLUSION: CuNiTi 35oC wires did not present better morphologic characteristics in comparison to the other wires with regard to surfaces and fracture region.

scholarly journals Structure and Fabric on the Burroughs Glacier, South-East Alaska

1963 ◽  
Vol 4 (36) ◽  
pp. 731-752 ◽  
Author(s):  
Lawrence D. Taylor
Keyword(s):  
Ice Age ◽  
Coarse Grained ◽  
Glacier Surface ◽  
Ice Flow ◽  
Fine Grained ◽  
Glacier Terminus ◽  
Basal Ice ◽  
Differential Movement ◽  
Slow Moving ◽  
Optic Orientation

AbstractThe Burroughs Glacier, south-east Alaska, is a slow-moving remnant (14×3km.) of a much more extensive glacier. It is now entirely below the firn line; ablation has revealed ice structures and fabric once 300 m. or more below the glacier surface.At the present glacier surface three kinds of ice are identified—foliated ice, coarse-grained border ice and very coarse-grained basal ice.Two systems of fine-grained foliation are present. Differential movement in the glacier has caused recrystallization along closely spaced planes. At the glacier surface this produces a steeply dipping longitudinal foliation. A gently dipping foliation, having a regional trough-like structure, may be associated with former stratification planes or with former spoon-shaped shear surfaces.The optic orientation of crystals in the coarser layers of the foliated ice shows three weak maxima, and in the finer layers a single weak maximum, corresponding to one of the coarse layer maxima, and normal to the gently dipping foliation plane. The other maxima in the coarse layers are orientated close to the poles of principal fracture planes.In the coarse ice the fabric shows a pattern with three maxima similar to that obtained in torsion shear experiments. In the glacier the pattern may be formed by shear near the glacier bottom or along gently dipping foliation planes. Grain-size increases towards the glacier terminus, especially in the stagnant ice zone.Structural evidence suggests that in the early stages of the Little Ice Age the ice flow was from west to east. Later it was to east and west from an ice crest in the upper Burroughs Glacier. Structures produced by present movement have been superimposed on older structures.

Holocene Environmental Change, Artiodactyl Abundances, and Human Hunting Strategies in the Great Basin

2004 ◽  
Vol 69 (2) ◽  
pp. 235-255 ◽  
Author(s):  
David A. Byers ◽  
Jack M. Broughton
Keyword(s):  
Environmental Change ◽  
Great Basin ◽  
Late Holocene ◽  
Coarse Grained ◽  
Population Increase ◽  
Hunting Behavior ◽  
Fine Grained ◽  
Hunting Strategies ◽  
Bonneville Basin ◽  
Holocene Environmental Change

Despite a deep Great Basin tradition of incorporating paleoenvironmental change within ecologically oriented analyses of past human lifeways, there has been little attention focused on Holocene variation in artiodactyl abundances and the human hunting strategies dependent upon them. Here, we draw upon recently generated paleontological evidence from Homestead Cave of the Bonneville Basin to document a late Holocene artiodactyl population increase. We then use the prey model of foraging theory to predict late Holocene increases in the hunting of artiodactyls, relative to lagomorphs. That prediction is then tested against several fine-grained archaeological records of hunting behavior in the Bonneville Basin, Hogup Cave and Camels Back Cave, and a variety of more coarse-grained faunal records from throughout the Great Basin. Close fits are found between the deductively derived prediction and the empirical records of hunting behavior: dramatic proportional increases in artiodactyl hunting occurred during the late Holocene. The results have far-reaching implications for our understanding of prehistoric human adaptations in the Great Basin.

Origin of the Whewellite-Rich Rock Crust in the Lower Pecos Region of Southwest Texas and Its Significance to Paleoclimate Reconstructions

1996 ◽  
Vol 46 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Jon Russ ◽  
Russell L. Palma ◽  
David H. Loyd ◽  
Thomas W. Boutton ◽  
Michael A. Coy
Keyword(s):  
Calcium Oxalate ◽  
Late Holocene ◽  
Paleoclimate Reconstruction ◽  
The Holocene ◽  
Climate Fluctuations ◽  
The Past ◽  
Desert Species ◽  
Paleoclimate Reconstructions ◽  
Wet Climate ◽  
Lower Pecos

A calcium oxalate (whewellite)-rich crust occurs on exposed limestone surfaces in dry rock and open air shelters in the Lower Pecos region of southwest Texas. The crust, which also contains gypsum and clay, formed over silica-rich limestone during the Holocene. SEM and optical photomicrographs reveal similarities between whewellite microstructures and the lichen Aspicilia calcarea. This desert lichen is known to produce calcium oxalate, and has been found in several sites in the region. The ubiquity of the whewellite-rich crust in the Lower Pecos shelters suggests that the lichen flourished in the past. Since A. calcarea is a desert species, the virulence of the organism likely peaked during xeric climate episodes then waned during mesic periods. Thus, radiocarbon ages of whewellite would correspond to dry climate periods experienced in the region, while periods with few or no 14C data would indicate wet climate episodes. A preliminary paleoclimate reconstruction based on fourteen AMS14 C dates indicates the Lower Pecos experienced dry to wet climate fluctuations during the late Holocene. This reconstruction generally agrees with other models established for Texas.

scholarly journals Hummocks in alpine tundra, northern British Columbia, Canada: distribution, morphology and organic carbon composition

2019 ◽  
Vol 5 (3) ◽  
pp. 127-147
Author(s):  
Marjolaine Verret ◽  
Yifeng Wang ◽  
Jean Bjornson ◽  
Denis Lacelle
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Organic Carbon ◽  
Late Holocene ◽  
Organic Content ◽  
Alpine Tundra ◽  
Carbon Density ◽  
Freezing And Thawing ◽  
Fine Grained ◽  
Alkyl Groups

Hummocks develop by cryoturbation in fine-grained frost-susceptible soils and their stage of maturity may affect the translocation of organics in Cryosols. This study examines the distribution and morphology of hummocks in the Chuck Creek Trail Valley (northern British Columbia) and determines the quantity, distribution, and composition of organic matter in their soils. Hummocks occupy about 5%–20% of the valley and their morphology is largely affected by their silt content. Cryoturbated intrusions, radiocarbon dated to 2814 and 1648 cal year B.P., suggest that hummock development was initiated during the cooler late Holocene. Hummocks have an average soil organic carbon density of 16.3 kg m−2 in the uppermost 1 m, with 62% stored in the top 25 cm. Organics are mainly present as particulate organic matter in the O-horizon (25%–80%), characterized by degradable alkyl C and O/N-alkyl groups, but occur as mineral-associated organic matter (96%–98%) composed of recalcitrant aromatic and aliphatic C groups in the underlying B and C horizons. Minor differences in organic content and composition occur between hummock tops and troughs, and between hummocks showing different stages of maturity. In the absence of an observed frost table, contemporary hummock activity is attributed to seasonal freezing and thawing.

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