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Field Class Replacement Assessment - “Review the formation and evolution of the English Lake District over the last 25,000 years, providing a detailed description of the different phases and processes that have shaped its structure and current day appearance.”
The Lake District is a region of Great Britain famous for and characterised by its scenery. Craggy peaks and boulder-strewn corries contrast with wooded valleys, farmland, conifer plantations, and ribbon lakes. As well as attracting huge numbers of tourists, the scenery of the Lake District has also afforded it National Park status, and since the publication of the first scientific account of its geology in 1820, by local guide Jonathan Otley, its landscape has become one of the most extensively studied in the British Isles. Through the past 25,000 years, there have been many changes in the landscape of the Lake District, most prominently by glaciation, which is responsible for the general shape of much of the district. The arrival of man also brought about many changes, notably to vegetation and land use.
An Overview of Lake District Geology
The rocks visible at the surface of the Lake District can be roughly divided into three main groups which trend south-west to north-east:
• Skiddaw Slates – these are the oldest rocks in the Lake District, dating from the Ordovician period (c.500 Ma). They are thought to have been formed by the deposition of mud and silt on the seabed, in deep, still water.
• Borrowdale Volcanic Series –formed during a subduction event at c.450 Ma, the Borrowdale Volcanic Series consists of volcanic lavas and pyroclastics. The bulk of the district’s higher, craggier peaks are in this region.
• Windermere Group – slates, shales and sandstones from the...
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...sis. Large numbers of pollen grains are produced for reproduction, and dispersed by the wind. The vast majority shrivel up and are lost, but some fall in areas where their distinctive casings can be preserved – peat bogs favour such preservation (Millward & Robinson, 1970). If a core is taken through many layers of peat, the pollen grain casings present across its depth can provide a chronological record of what plants were present across the time period represented by the core.
The early soils in the Lake District are thought to have been far more alkaline than they are today, particularly those formed from the rocks of the Borrowdale Volcanic Series, which displays veins of white calcite (Pearsall & Pennington, 1973). If a fresh surface of Borrowdale Volcanic rock is exposed, it will react with hydrochloric acid, showing that calcium carbonate is present.
Marshak, S. (2009) Essentials of Geology, 3rd ed. New York: W.W. Norton & Company, ch. 11, p. 298-320.
The shelf-edge includes carbonate-to-clastic facies transition and tectonic uplift and erosion of the carbonates followed by deposition of the clastics. The Saint Peter Sandstone is a well-sorted, almost pure quartz arenite deposited during a major mid-Ordovician low stand. Clastics spread across an exposed carbonate platform by transportation. This is shown by the well-rounded, frosted texture of the quartz grains.
The Kimmeridge Clay Formation is the penultimate formation of the onshore British Jurrasic Succession. William Smith was the first to document this distinct formation on his map of 1815, and to name as the Oaktree Soil. In 1817, he gave the name Oaktree Clay for the layers of clay between the “Portland Rock” and “Coral Rag and Pisolite” but in 1816 Webster was the first to describe in details the formation and changed to the name now known as kimmeridge Clay Formation after the English village of Kimmeridge on Dorset’s “Jurassic Coast” a place frequently visited by fossil hunters. (Cox and Gallois, 1981).
The third alluvial deposition consists of sand, silt and minor inter-bedded gravel, and again indicates Brimbank Park’s changing geology over time. (Geological map of Victoria, 1973). These deposits, as well as a nearby fault suggest volcanic activity 5-1.6 million years ago, which explains the olivine basalt (fig. 2) deposits which date back to to the Silurian and Tertiary period.
...e morphed it into the quartzite that is seen surrounding the butte (4). Rocks that undergo this process are called metamorphic rock, which is the same as the rock seen years ago by dinosaurs and other extinct creatures. The quartzite rocks were formerly seafloor sediment that was forced upwards, and then surrounded by lava basalt flows. Once erupted through fissures and floods through out most of the area, lava flow eventually created enough basalt to form a thickness of about 1.8 kilometers (1). All of this basalt flow eventually led to the covering of most mountains, leaving the buttes uncovered. The igneous lava flows and loess is reasons that the Palouse consists of such sprawling hills, and rich soil for farming (2). In result of the lava flows, the Precambrian rock Quartzite was formed. And lastly covered by the glacial loess, which were carried by the wind.
Hess, D., McKnight, T. L., & Tasa, D. (2011). McKnight's physical geography (Custom ed. for California State University, Northridge ; 2nd Calif. ed.). New York: Learning Solutions.
volcanoes that are located in our region. In our Big Bend and Fort Davis areas, when
Shortly following the glacial retreat of the upper Great Lakes region around 11,000 B.C., the flora and fauna
This leads to a decrease in local biodiversity throughout the waterway and Great Lakes, causing instability in their environments that leads to further population decline for these species and others [12]. The causes for this decline vary depending on species but often include overfishing, threat from invasive species, and, of special concern in the Trent Severn Waterway, habitat fragmentation [8][9][10][11][12]. Examples of habitat fragmentation are dams and lift locks that break up natural aquatic areas and interfere with natural flow of individuals in areas that were previously one continuous habitat [13]. This occurs annually at the Kirkfield lift lock where aquatic life can go up or down the lock between mid-May and mid-October while the lock is operational, but are stuck between mid-October and mid-May [2]. While fish do go dormant in the winter, the american eel, channel darter, and lake sturgeon are active from 5°C to 25°C and do not go dormant until early December and reactivate in early May [14][15][16][17]. Thus, the Kirkfield lift lock limits these species’ habitat ranges for several weeks per year, which causes population decline
Riley, C.M. "Lahars." Geological and Mining Engineering Sciences. Michigan Tech. Web. 6 Feb. 2010. .
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.
P.Wellman, Ian McDougal,(1974),Cainozoic igneous activity in Eastern Australia, Research School of Earth Sciences, ANU Canberra, Elsevier Scientific Publishing Company,pg 52
...These rocks include indurated conglomerates, coarse-grain granites, and Arkosic and breciated granites. Furthermore, there are evidences to indicate that faulting took place in the area. Hydrothermal and epithermal action must have intruded the rocks in the Goldfield area forming small stringers of quartz. There are also evidences of sedimentary rocks such as sandstones, limestone and conglomerates found near Roosevelt Lake (Eppinga, 2006).
Rapidly changing human activity within the Stratford since 1867 to this present day puts huge pressures on the natural environment's ability to adapt and change. These may be further complicated by the influences of climate change, such as extremes in weather. These bar graphs above show the changes in land use over one hundred and forty seven years.
Tectonic Rock Cycle involves different stages in which the cycle are carried out by rocks of different Parent