scholarly journals Age of Rotational Landslides in the Cypress Hills, Alberta-Saskatchewan

2007 ◽  
Vol 40 (3) ◽  
pp. 239-248 ◽  
Author(s):  
Mark R. Goulden ◽  
David J. Sauchyn
Keyword(s):  
Late Holocene ◽  
Microscopic Analysis ◽  
Carbon Cluster ◽  
Organic Content ◽  
Soil Horizons ◽  
The West ◽  
Relative Age ◽  
Buried Soil ◽  
Geomorphic Processes ◽  
Landslide Debris

ABSTRACTThe topography of the west block of the Cypress Hills indicates that fluvial dissection of the plateaux and subsequent rotational landsliding of valley sides have been the dominant Quaternary geomorphic processes. This paper presents a preliminary chronology of rotational landslides based on the relative ages of 17 landslides and on 3 absolute dates. Four indices of relative age were used: organic content in Ah and B soil horizons, the size and coverage of lichens and weathering rind thickness on boulders exposed by landsliding, and the concavity and gradient of gullies in landslide debris, One landslide occurred in 1965. Organic materials collected from buried soil horizons beneath depressions on 3 other landslides were radiocarbon dated at 1235 ± 105, 1635 ± 105 and 7259 ± 165 yrs. BP. Microscopic analysis of the organic material revealed that the oldest sample was contaminated with older carbon. Cluster analysis of the relative age data in conjunction with 3 acceptable absolute dates suggests that the landslides under study have occurred during late Holocene time.

Investigation into the diet of the central rock-rat (Zyzomys pedunculatus)

2003 ◽  
Vol 30 (5) ◽  
pp. 513 ◽  
Author(s):  
Theresa J. Nano ◽  
Cate M. Smith ◽  
Elizabeth Jefferys
Keyword(s):  
Sample Size ◽  
Conservation Status ◽  
Microscopic Analysis ◽  
Faecal Pellet ◽  
Northern Territory ◽  
The West ◽  
Major Food ◽  
Seasonal Shift ◽  
Leaf Consumption

The diet of the rare central rock-rat, Zyzomys pedunculatus, was assessed by microscopic analysis of 18 faecal pellet samples collected from four different sites in the west MacDonnell Ranges in the Northern Territory. Samples were collected from the four sites in summer (n = 13), one site in winter (n = 3), and two sites in spring (n = 2). Four major food categories were observed in the samples: seed, leaf, stem and insect. Seed was by far the most dominant food in the overall diet of Z. pedunculatus, making up 72% of identifiable particles, leaf was secondary (21%), while stem and insects contributed only 3% and 4% respectively. Although the sample size was small, no major seasonal shift between seed and invertebrate dominance was evident. Seed dominated the diet in both summer and winter, though winter seed consumption was lower (78% v. 58%). The level of seed consumption in the two spring samples was highly divergent (38% v. 93%), stressing the need for more samples to be collected from dry periods. Lowered rates of seed consumption during winter and in one of the spring samples were accompanied by increases in leaf consumption. Insect consumption remained low across all sampled seasons, suggesting that this species is not an omnivore. Rather, the dominance of seed in the diet suggests that Z. pedunculatus is primarily a granivore, a finding that has implications for the conservation status and management of this little-known species.

scholarly journals Amounts of throughfall and lysimetric water in a sub-mountain beech forest in the Kremnické vrchy Mts. (West Carpathian Mts., Slovakia)

2008 ◽  
Vol 54 (No. 5) ◽  
pp. 207-211 ◽  
Author(s):  
R. Janík ◽  
J. Pichler
Keyword(s):  
Beech Forest ◽  
Soil Horizons ◽  
Average Amount ◽  
Experimental Site ◽  
The West ◽  
Lysimetric Water ◽  
Clear Cut ◽  
Beech Stand ◽  
Soil Percolation ◽  
Soil Lysimeters

The paper deals with throughfall and soil percolation in a sub-mountain beech forest situated at the Ecological Experimental Site (EES) Kremnické vrchy Mts. (the West Carpathian Mts., Slovakia). The research was conducted in 1988–2008. The throughfall was sampled at regular periods, both from the open plot (clear-cut) and from the plot with complete stocking, covered with a mature beech stand. The soil percolation was evaluated with soil lysimeters. In 1989 and 2004, the plots were treated with cutting – with the aim to reduce the current stocking. The average amount of throughfall was 772.2 mm in the open plot and 616.3 mm in the control. The amount of soil percolation decreased with increasing depth: from 398.9 mm to 103.8 mm in the control and from 488.8 mm (surface) through 169.9 mm (10 cm) to 188.8 mm (25 cm) in the open plot. The differences between the plots were statistically highly significant. No significant differences were found between the soil horizons.

Spatiotemporal Variation in ΔR on the West Coast of North America in the Late Holocene: Implications for Dating the Shells of Marine Mollusks

2020 ◽  
Vol 85 (4) ◽  
pp. 676-693
Author(s):  
Ian Hutchinson
Keyword(s):  
North America ◽  
West Coast ◽  
Late Holocene ◽  
Southern Oscillation ◽  
Tidal Energy ◽  
Spatiotemporal Resolution ◽  
The West ◽  
Summer Maximum ◽  
High Alkalinity ◽  
High Degree

Radiocarbon ages on mollusk shells, which account for about half of the more than 8,000 dates from cultural deposits on the west coast of North America, need to be corrected for the local marine reservoir effect (ΔR) to yield true ages. Assays on “prebomb” shells show that ΔR increases poleward, echoing the age gradient in offshore waters. The meridional gradient in ΔR is not appreciably affected by the transition either from an upwelling regime to a downwelling regime north of 40°N–45°N or from a winter maximum-high alkalinity river discharge pattern to a summer maximum-low alkalinity pattern at the same latitude, probably because these changes are offset by increasing storminess and tidal energy in coastal areas. Mesoscale variations in ΔR along this gradient are attributable to contrasts in shore morphology and exposure. Data from 123 shell-wood pairs reveal similar patterns of temporal variation in ΔR in the late Holocene in the coastal ecoregions. The characteristic temporal pattern echoes phases of variable El Niño-Southern Oscillation (ENSO) activity. The high degree of variability in ΔR argues against the indiscriminate application of regionally uniform or trans-Holocene ΔR values and demands improvements in spatiotemporal resolution if shell is used to date cultural deposits.

Adequacies and deficiencies of alpine and subalpine treeline studies in the national parks of the western USA

2010 ◽  
Vol 35 (1) ◽  
pp. 19-42 ◽  
Author(s):  
Clayton J. Whitesides ◽  
David R. Butler
Keyword(s):  
Climate Change ◽  
Content Analysis ◽  
National Parks ◽  
Fine Scale ◽  
Scale Analysis ◽  
The West ◽  
Western Usa ◽  
Alpine Treeline ◽  
The Impact ◽  
Geomorphic Processes

To mitigate the impact of direct human activity on treeline pattern and process, much alpine treeline research in the western USA has been conducted in nationally protected areas. The use of treeline as a proxy for climate change has been assessed in parks throughout the west but often at the expense of geology or geomorphology as controls of treeline variation. The dissimilar geology and geomorphic processes of the western national parks suggest that treeline may respond differently between national parks when subjected to disturbance. Therefore, predicted vegetation response to disturbance across the western USA may provide a limited assessment of change beyond fine-scale analysis due to data collection from a limited number of national parks containing alpine treeline. We performed a content analysis on previous research that examined alpine treeline in national parks and classified each treeline study as anthropogenic, orographic/edaphic, or climatic according to the primary factor attributed to treeline control. Results indicated that the three types of treeline are not uniformly studied. Climatic treeline is most commonly studied whereas anthropogenic and orographic/edaphic studies are often lacking. Furthermore, several western national parks are entirely devoid of anthropogenic and orographic treeline research. Similar findings exist for treeline studies in protected places worldwide. More research in protected places is required to broaden our understanding of multiple treeline processes across both regional and worldwide extents.

Late-Holocene marine radiocarbon reservoir correction (ΔR) for the west coast of South Africa

The Holocene ◽  
2012 ◽  
Vol 22 (12) ◽  
pp. 1481-1489 ◽  
Author(s):  
Genevieve Dewar ◽  
Paula J Reimer ◽  
Judith Sealy ◽  
Stephan Woodborne
Keyword(s):  
South Africa ◽  
West Coast ◽  
Late Holocene ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Weighted Mean ◽  
The West ◽  
Proxy Data ◽  
Carbon Reservoir ◽  
Carbon Component

In order to calibrate radiocarbon ages based on samples with a marine carbon component it is important to know the marine carbon reservoir correction or ΔR value. This study measured the ΔR on both known-age pre-bomb marine shells and paired marine and terrestrial samples from two regions on the west coast of South Africa: the southwestern Cape and Namaqualand. Pooling the data by region produces ΔR values that are similar enough to use a west coast weighted mean ΔR of 146 ± 85 14C years to correctly calibrate marine shell or mixed marine and terrestrial 14C ages. There are however temporal differences in ΔR throughout the Holocene, which we compare with proxy data for upwelling and sea surface temperatures.

Temporal analysis of the diet of the central rock-rat

2013 ◽  
Vol 35 (1) ◽  
pp. 43 ◽  
Author(s):  
G. P. Edwards
Keyword(s):  
Microscopic Analysis ◽  
Temporal Analysis ◽  
Past Century ◽  
The West ◽  
Faecal Pellets ◽  
The Past ◽  
Faecal Samples ◽  
Dry Conditions ◽  
Central Australia ◽  
Solanum Spp

The central rock-rat (Zyzomys pedunculatus) is an endangered endemic rodent that has undergone a dramatic range contraction over the past century. It is currently known from only a small area of the West MacDonnell Ranges near Alice Springs. A previous investigation into the species’ diet that analysed a small number of faecal samples concluded tentatively that it was a granivore. The present study aimed to establish the dietary patterns of Z. pedunculatus across a two-year period in central Australia during which rainfall fluctuated markedly. Diet was determined through the microscopic analysis of material in faecal pellets of Z. pedunculatus trapped at approximately three-month intervals at five sites at Ormiston Gorge. Seed was found to be the most important dietary item, comprising on average 57.0% of the diet across sample periods. Under dry conditions, the amount of seed material in the diet declined and the amount of stem material increased. Plant material from 15 genera was recorded in the diet, most notably Sida spp., Solanum spp. and Triodia brizoides. All of the plant genera identified in the diet to date are widespread and common in the range country of central Australia and most are considered fire tolerant. On the basis that the diet contains more than 50% seeds, Z. pedunculatus can be described as a granivore. However, the diet is broad and includes both seeds and vegetative material from a range of plant species.

scholarly journals CanWe Identify Macroscopic Texture of Coal under Microscopic Analysis Using Standard Petrographic Method?

2018 ◽  
Vol 3 (1) ◽  
pp. 32
Author(s):  
Ferian Anggara ◽  
Diyan Pamungkas ◽  
Wildan Guntur Prakoso
Keyword(s):  
Microscopic Analysis ◽  
Organic Content ◽  
Textural Analysis ◽  
Petrographic Analysis ◽  
Petrographic Method

Macroscopic texture in coals is not much getting attention to identify, becauseit is believed it doesn’t hold much information about the coal characteristics. It is nottrue because some of important coal characteristics lie in its organic content which is reflected in its macroscopic texture (Moore, 2016). Conventional petrographic method using crushed sample cannot distinguish such feature microscopically, since the macroscopic texture will lose its integrity during the preparation. Petrographic analysis using block samples provide information about microscopic texture that can represents its macroscopic texture. Components in textural analysis are divided into three types based on the size, band (more than 800 μm), lens (20–800 μm) and matrix (less than 20 μm). From the ratio between these three types of component and statistics, later it can be determined that nonbandedsamples have less value of ratio between band and lens per matrix, and there will be a borderline between banded and non-banded samples based on the value. Banded texture in macroscopic feature consists of vitrain bands, and under microscope it can beidentified as band and lens of macerals, while non-banded samples will mostly consist ofmatrix texture. Thus, it can be concluded that petrographic analysis using block samplescan be used to identify microscopic texture representing the macroscopic texture, and can be proven through statistics as used in this research.

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