No description available.

No description available.

No description available.

The area studied is situated in the southwestern part of Quebec Province near the Ontario border south of the Canadian Shield and along the Lake of Two Mountains. The area is approximately 463 square miles in size. [...]

The hunting economy of Cumberland Sound is analyzed according to the spring, break-up and open water seasons. Physical, biological and cultural factors interact in different manners and degrees to produce seasonal variations in the miles travelled per hunt, the duration of the hunt, the catch per man per day, the percentage loss of seals due to sinking, the miles travelled per seal landed, and the number of shots fired per seal killed. If the hunt is mechanized during all three seasons, then in terms of number of seals landed per hunter per day and net profit per landed seal, hunting is most efficient during the break-up season.

No description available.

No description available.

The purpose of this thesis is to describe in detail the fonn, lithology, elevation, tflt and distribution of abandoned glacial lake shoreline features and associated fluvioglacial and glacial deposits of Southwest Labrador Qnap 1). These characteristics are the result of distinct geomorphic and geophysical processes operating in late glacial and post glacial times and therefore a study of these characteristics reveals certain facts about the glacierization of Labrador-Ungava* and the deglaci erization of Southwest Labrador. The tilt of the glacial lake shoreline features is a result of glacial isostatic recovery and therefore the tilt of the shorelines reflects the differentiai thickness of the laurentide lee Sheet over Southwest Labrador during a certain stage in the Wisconsin period. If tilts of shorelines in other areas are used in conjunction with the tilts from Southwest Labrador it is possible to locate a point which represents a centre of ice dispersal of the Laurentide lee Sheet during a certain stage in the Wisconsin period.

This thesis investigates torrent erosion in Lake District mountain catchments, Northern England. A nested research approach was used. Detailed investigations were undertaken at two case study sites (Iron Crag, Raise Beck) together with a survey of torrents across the Skiddaw and Helvellyn massifs. At Iron Crag an annual sediment budget was constructed by monitoring hillslope, channel and fan processes. Particle size characteristics of sediments, and the history of fan development were investigated. Results show channel and bank sediments are the main source of material supplied to the fan. Large rainfall events cause significant change in the channel, banks and fan. The impact of different meteorological conditions on sediment characteristics is complex, however a seasonal cycle of sediment production (winter) and exhaustion (autumn) exists. Historically, initial fan aggradation predates 36 BC, but a rapid phase of deposition began between 1200-1400 AD. Investigations at Raise Beck focussed on a flood that occurred in January 1995 and caused channel avulsion and shallow landsliding. This was reconstructed using a range of geomorphological and sedimentological evidence. Palaeohydrological methods give a discharge between 27- 74 in s-1. whereas as rainfall-runoff values range between 4-6 m3 s-1. The magnitude of the 1995 flood was smaller than two 19th Century events, but would still exceed the capacity of contemporary engineered channels. The regional survey considered the characteristics and importance of torrents,mountain streams, and debris flows; and provided a context for work at the case study sites. The case study sites are distinct members of the regional populations. Raise Beck being the largest (133 ha) and highest (858 m O. D. ); Iron Crag amongst the smallest (2.4 ha) and lowest (600 m O. D. ). Overall, torrents and hillslope debris flows are minor components of the landscape (aerially 2.1 % Helvellyn massif, 0.4 % Skiddaw massif). Sites are preferentially located in regard to altitude and slope. Debris flows are related to geological type. Large torrent floods are relatively rare and can be broadly related to regional flood episodes. Contemporary debris flow activity is of low magnitude and frequency.

<p> This study focuses on the history of natural and human-induced environmental change as recorded in the sediments of two lakes: Mountain Lake in the Presidio National Park, San Francisco, California and Big Soda Lake, near Fallon, Churchill County, Nevada. The records of these lakes examined in this study cover approximately the last 2,000 years. Sediment cores from the lakes were dated with radiocarbon, lead-210, plutonium 240/239, tephrachronology, and the first appearance of non-native pollen types. The cores were analyzed to determine changes in stable isotopes (carbon and oxygen), sediment chemistry, fossil pollen, magnetic susceptibility, organic content, and brine shrimp cyst concentrations.</p><p> Big Soda Lake has been the subject of scientific investigation since the 19th Century and two famous scientists have previously worked at the site. First, the geologist, Israel Russell explored the lake in 1882 as part of his work on Pleistocene Lake Lahontan and provided the first scientific report on the lake. Later in 1933, Evelyn Hutchinson, the famous Yale limnologist, provided the first detailed limnological report for the lake. More recently in the 1980's, the lake has been studied by scientists from the United States Geological Survey. However, prior to the research reported on here, very little was known of the history of the lake or to what extent its sediments contained a useful record of environmental change. </p><p> The sediments of Big Soda Lake provide clear evidence for both natural and human-induced environmental change during the past 1600 years. The climate record developed from the analyses of stable isotopes of oxygen and carbon, sediment chemistry, and the concentrations of brine shrimp cysts show several significant shifts in climate. The early part of the record from A.D. 400-850 is period marked by a fluctuating climate, with alternating wet/dry phases each lasting several decades each (40-60 years). During the period known as the Medieval Climate Anomaly (MCA)(A.D. 850-1400), we observe at least two relatively dry periods from A.D. 850-1150 and A.D. 1260-1400. Between the two dry phases, there is a pronounced wet period from A.D. 1150-1260. This wet period matches fairly well with evidence presented in other paleoenvironmental studies in the western Great Basin. During the Little Ice Age (LIA), the evidence indicates that the Big Soda Lake area was not always colder and/or wetter, but that it was in fact drier and perhaps warmer from A.D. 1400-1700 than it had been in the previous millennium. Pronounced dry phases were observed around A.D. 1400, A.D. 1500 and A.D. 1650. The wettest period during the LIA came between A.D. 1750-1800. </p><p> The human impact record at Big Soda Lake developed from the analyses of stable isotopes of oxygen and carbon, sediment chemistry, and the concentrations of brine shrimp cysts show several dramatic changes in and around the lake since Anglo American settlement of the area began, in the 1850's. Several human impacts have been identified, including regional mining activity, soda salt extraction from the lake, and irrigation induced rising groundwater levels in the last century. Two of these events have dramatically impacted the lake in that time. Firstly, the development of a commercial soda manufacturing and processing facility at the lake beginning in 1875 until the early 20th century; and secondly, the development of irrigation agriculture which led to an 18 m rise in lake level in the first few decades of the twentieth century. The sediments at Mountain Lake provide evidence of unprecedented heavy metal contamination at the San Francisco Presidio during the past 60 years. The lake evidence is consistent with local land-use changes initiated by the arrival of Europeans in the area after 1776 and the construction of California State Highway 1 adjacent to the lake in the late 1930's. The study shows how small water bodies alongside roads can concentrate heavy metals and demonstrates the need for careful scientific investigation of sediments earmarked for dredging to determine what if any contaminants are present. </p><p> A key outcome of the Mountain Lake research carried out as part of this dissertation was that in the Fall of 2011 a Federal judge ordered the California Department of Transportation (Caltrans) to pay 13.5 million dollars to the Presidio Trust so that the contaminated sediments could be removed and further run-off from the road be prevented from entering the lake.</p>