Glacial Till
The characteristics of glacial till reflect the erosional, transportational and depositional history of the constituent sediment.’
Glacial till is a heterogeneous mixture of rock fragments ranging in size from clay to boulders and is deposited directly from glacial ice without water transport. (Strahler A. H. & Strahler A. N. 1976). Ice sheets deposited in the Pleistocene period may be more than 30 m deep and inevitably the constituents of glacial till will reflect the retreats, advances and stationary phases of the ice which have taken place during the history of a glacier since its formation.
I shall outline the various forms of glacial till, giving consideration to the type of prevailing climatic conditions which give rise to their formation and deposition to illustrate how the constituent sediment does provide evidence for glacial activity over time.
As glaciers are so effective at erosion and transport, large quantities of debris is also associated with them. According to it’s location with respect to the glacier, such debris transported as ice mass may be divided into three main categories. There are three main positions that a glacier can transport debris, englacial debris which occurs within the glacier, supraglacial debris which occurs on the glacier surface and subglacial debris which occurs on the base of the glacier, (please look at figure 15.12 below). While debris is being transported it may remain in any one of these positions until it is deposited by the ice directly or it may end up being reworked by melt water.
Deposition of the transported material is a complex process, but the fraction deposited directly from the ice is called till. It consists of a wide range of grain sizes, so it is often referred to as boulder clay. It also posses very little stratification and frequently contains far travelled erratic material, which tends to have clast with edges and corners blunted by abrasion. (Briggs D. Et. Al. 1997)
There are two main different types of till which have been recognised, lodgement till and ablation till. Lodgement till is laid down subglacially when debris is released directly from the sole of the ice. Ablation till accumulates initially in a supraglacial position and is later lowered to the ground surface by undermelting. Ablation till can be further subdivided into meltout till and flow till. Meltout till is a direct product of ablation continuing beneath a cover of detritus and flow till consists of debris that has built up on ice and after saturation with melt water becomes so unstable that it flows or slumps into near by hollows.
This is a report based on three days of observations and testing in the region known as the Peterborough drumlin field. It will address a variety of regional elements, such as climate, soil, vegetation, hydrology, geomorphology, and geology. A variety of sites located on the Canadian Shield, the zone of thick glacial deposits to the south, and the transition between them will be the focus of the report. It is supplemented with previous research on the region. September 8, 1999, day one of the field study involved an area of largely granite bedrock that is part of the Canadian Shield and is the most northern point of study (see Map 2). September 9, 1999, day two, involved three main areas of study: the Bridgenorth esker (Map 3), Mark S. Burnham Park (Map 4), and the Rice Lake drumlin (Map 6). These sites are in areas of thick glacial deposits. September 10, 1999, day three, involved studying the Warsaw Caves (see Map 5) as a transition zone between Precambrian Shield rock to the north and Paleozoic rock to the south. A general map of the entire study region is provided by Map 1.
Sedimentary rock from the older Silurian Period is further from the river banks (Geological map of Victoria, 1973). Mudstone, inter-bedded shale and greywacke depositions indicate the Maribyrnong River may have previously taken a different shape, and younger sediments have replaced the older sediments in more recent geological periods.
...Clague, John J., Luckman, Brian H., Wiles, Gregory C. “Tree-Ring Dating of the Nineteenth-Century Advance of Brady Glacier and the Evolution of Two Ice- Marginal Lakes, Alaska.” The Holocene 21.4 (2001): 641-649. Sage Journals. Web. 9. Feb. 2014.
Avalanches kill back country recreationalists every year, including skiers, snowboarders, snowshoers, and snowmachiners. All back country users should have knowledge of the basic physics of avalanches to help them evaluate local and regional potential for slides. The foundation of this knowledge comes from understanding how the surrounding environmental conditions in previous weeks, previous days, and the day in question all contribute to snow stability or instability, and how specific factors affect snow on a micro-scale, which determines how snow slopes will behave on a macro-scale. There are two major types of avalanches (excluding debris avalanches from broken cornices and ice formations). These are point releases, or loose snow slides, and slab avalanches. While point releases can be dangerous and should be avoided, slab avalanches are much more catastrophic and account for most of the backcountry avalanche disasters involving humans. Basic physics of point releases are discussed here, followed by a discussion on the basic physics of slab avalanches, and how external factors contribute to the stability or instability of a snow covered slope.
Instead of offering amnesty to whistleblowers for a limited time, we must implement this rule on a permanent basis, and let it be known that it is necessary to report suspicious behavior if noticed without any consequence. The permanent implementation will keep all the employees honest with each other and the company thus minimizing the chance of corruption.
Studying the effects of weathering and erosion on the uplifted and exposed basalt sill is important to understanding the geological events that lead to mass movements in the area. My researc sought to determine exactly what happens to a rock that has been exposed to natural weathering such as thermal, biological, chemical, and wet-dry also referred to as slaking, on a qualitative and quantitative scale. The weathering of the rocks, though apparent on the exterior of the sample, has an extreme and transformative effect on the internal structure (Gupta et al., 1999). Weathering disrupted the internal crystalline structure by producing microfactures, voids, and the deposition of clay minerals (Gupta et al., 1999). Basalt is heavily affected by weathering when concerning porosity and the formation of ...
The term snow is usually restricted to material that fall during precipitation in the form of small white ice crystals formed directly from the water vapour of the air at a temperature of less than 0°C and has not changed much since it fell. A fall of snow on a glacier surface is the first step in the formation of glacier ice, a process that is often long and complex (Cuffey and Paterson, 2010). The transformation of snow to ice occurs in the top layers of the glaciers and the time of the transformation depends mostly on the temperature. Snow develops into ice much more rapidly on Temperate glaciers, where periods of melting alternate with periods when wet snow refreezes, than in Polar glaciers, where the temperature remains well below the freezing point throughout the year. The density of new snow as it falls on glacier surface depends mostly on the weather conditions. In clam conditions, the density of new snow is ρs ≈ 50 – 70 kg m-3 (Table 1.1). If it is windy, there is breaking of the corners of snowflakes, and the density is more like ρs ≈ 100 kg m-3. After the snow has fallen on the surface, there are three processes that are all active together and work to transform the snow to ice.
This artic tundra is mainly formed by permafrost, “a layer of permanently frozen subsoil in the ground. Putting frozen ground and flat landscape stops the drainage of water. As the water is being held up on the surface it makes ponds and bogs that give moisture for the plants, or countering the low precipitation. “The periodic freezing and thawing of the soil forms cracks in the ground in regularly patterned polygons”. Some areas are not drained very well causing irregular landforms. Some of these landforms like the following hummocks, or knolls, frost boils, and earth stripes. Another common area to the alpine tundra is a “bare rock covered ground” also known as fell fields, in which not alone support but helps the growth of lichens. The many “microhabitats” given by these landforms provide a variety to the tundra’s landscape.
In order for the body to maintain homeostatic levels of energy, blood glucose regulation is essential. Glucose is one of the body’s principal fuels. It is an energy-rich monosaccharide sugar that is broken down in our cells to produce adenosine triphosphate. In the small intestine, glucose is absorbed into the blood and travels to the liver via the hepatic portal vein. The hepatocytes absorb much of the glucose and convert it into glycogen, an insoluble polymer of glucose. Glycogen, which is stored in the liver and skeletal muscles, can easily be reconverted into glucose when blood-glucose levels fall. All of the body’s cells need to make energy but most can use other fuels such as lipids. Neurons; however, rely almost exclusively on glucose for their energy. This is why the maintenance of blood-glucose levels is essential for the proper functioning of the nervous system.
Describe how carbohydrates are digested and absorbed and how the body regulates glucose in the
The Don Valley Brickwork consists of many different layers of geological deposits, allowing us to observe and have a better understanding of how the sediments we see today are formed. The most bottom layer in the Brickworks are from the Georgian Bay Formation, and consists of grey- shale bedrocks. Fossils are often found in this layer and it is estimated that this deposit of sediments is around 445 million years old. Above the bedrocks is a thin layer of grey clay sand and gavels left behind by the Illinoian Glacier. This layer is called the York Till and occurred around 135,000 years ago. The next layer consists of a sandy deposit called the Don Formation, which is formed by the Sangamonian Interglacial Stage. Many plant and animal fossils are found in this layer due to warmer climate around 120,000 years ago. Above it lies the Scarborough Formation, which consist of clay and sand. This sediment likely occurred 115 - 106,000 years ago. The next layer above is the Poetry Road Formation, and consist of sand and gravel. This layer is likely formed during the early Wisconsin glacial substage around 106- 75,000 years ago. Higher is the Sunnybrook Drift which was formed 60 – 75,000 years ago. And on the surface, is the Halton Till, which was left behind by the final push of the Wisconsin Glacier.
With the emergence of unethical practices found in international corporations, whistleblowing has been more and more common. A whistleblower is a person who exposes any kind of information that is deemed illegal, immoral, or dishonest. In SNC-Lavalin, the whistleblower was justified. In this case, the senior executives were paying bribes and taking money from mega projects won under the Gadhafi regime (Wikipedia, 2015, n.p). There are several issues in this case. First, paying bribes and siphoning off millions of dollars from the corporation would eventually lead to the company losing money because building mega projects in politically unstable countries would prove problematic. A sudden regime change would render the contracts useless, as new regimes would not recognize SNL-Lavalin’s contracts as legitimate. In addition, the international community may introduce sanctions that would affect
Perry Smith was a short man with a large torso. At first glance, “he seemed a more normal-sized man, a powerful man, with the shoulders, the arms, the thick, crouching torso of a weight lifter. [However] when he stood up he was no taller than a twelve-year old child” (15). What Smith lacked in stature, he made up in knowledge. Perry was “a dictionary buff, a devotee of obscure words” (22). As an adolescent, he craved literature and loved to gain insight of the imaginary worlds he escaped into, for Perry’s reality was nothing less than a living nightmare. “His mother [was] an alcoholic [and] had strangled to death on her own vomit” (110). Smith had two sisters and an older brother. His sister Fern had committed suicide by jumping out of a window and his brother Jimmy followed Fern’s suit and committed suicide the day after his wife had killed herself. Perry’s sister, Barbara, was the only normal one and had made a good life for herself. These traumatic events left Perry mentally unstable and ultimately landed him in jail, where he came into acquaintance with Dick Hickock, who was in jail for passing bad checks. Dick and Perry became friends and this new friendship changed the course of their lives forever. Hickock immediately made note of Perry’s odd personality and stated that there was “something wrong with Little Perry. Perry could be such a kid, always wetting his bed and crying in his sleep. And often [Dick] had seen him sit for hours just sucking his thumb. In some ways old Perry was spooky as hell. Take, for instance, that temper of his of his. He could slide into a fury quicker than ten drunk Indians. And yet you wouldn’t know it. He might be ready to kill you, but you’d never know it, not to look at it or listen to it” (108). Perry’s short fuse and dysfunctional background were the two pieces to Perry’s corrupt life puzzle that soured and tainted the final “picture”.
Chasing Ice covers the long debated topic of global warming and whether or not human activity is currently causing global temperatures to rise. Evidence suggests that increased carbon dioxide emissions over the past couple hundred years are responsible for the warming of the Earth’s surface, and thus increasing the levels of the ocean due to an accelerated rate of ice melting. We discussed this same topic in class and how humans are contributing to the greenhouse effect which plays a large role in trapping these unnatural amounts of gases such as carbon dioxide in the Earth’s atmosphere and causing a rise in the number of natural disasters around the world.
There are numerous metabolic diseases that affect people all around the world. One of the most common metabolic diseases is diabetes which involves carbohydrate metabolism. Carbohydrate metabolism starts with digestion in the small intestine where simple carbohydrates are absorbed into the blood stream (1). Blood sugar (glucose) concentrations are managed by three hormones: insulin, glucagon, and epinephrine. When glucose concentrations in the blood become elevated, insulin is secreted by the pancreas. Insulin stimulates the transfer of glucose into the cells, especially in the liver and muscle tissue, although other organs are also able to process glucose (2).