On Monday June 5th 2006, the geography class of Windermere St Annes pursued their research of glaciation and its effects on landscapes by studying Easedale Valley; so the aim of the field trip was to see if glaciation had affected the landscape of Easedale. The hypothesis that I devised is: “The effect of glaciation has significantly impacted on Easedale’s current landscape”. I used a series of techniques such as field sketching, observing, measuring striations, taking photographs and sorting pebbles into classes according to Power’s Scale, to see if my hypothesis was true or false.
I spent the day gathering primary research and seeing how my past knowledge can fit and apply to my observations. While doing this, I kept in mind a few questions that would help me reach a suitable conclusion. 1. In which direction did the former glacier/s flow? 2.
What evidence is there in the landforms of Easedale Valley of glaciation? 3. Why is the Easedale Tarn located where it is? Using the techniques mentioned above, and keeping the above questions in mind, I studied Easedale, which is located in the county of Cumbria, in Lake District National Park.The study location is situated north-west of the town of Grasmere. Analysis Field Sketch 1: Roche Moutonni??e (pg 6) In the sketch, it’s showing a large mound of borrowdale volcanic granite which starts off smoothly curved and then drops down into a steep and slightly jagged surface.
This general structure of the borrowdale granite instantly suggests that it’s a roche moutonnee. This feature is formed when the ice flow reaches an obstacle, such as granite hard rock, and abrasion occurs due to the pressure and friction increase from the glacier’s intense weight.The friction causes the base of the glacier to melt so when the glacier moves over the edge of the rock, the water drips down and fills gaps and cracks- which then leads to freeze thaw (shown as glacial plucking in the diagram). This is when the water fills in the rock cracks and re-freezes; as it does, it expands and widens the rock cracks.
When the ice then melts, the expanded rock no longer has the ice’s support and so it breaks up and crumbles creating a jagged surface. My observations, converted into a field sketch, support this theory making it an authentic suggestion that this is an example of roche moutonnee.Also, the direction of the ice flow is determined by the striations left on the roche moutonnee, I’ve drawn a graph to show this. Field Sketch 2: Corrie (pg 7) The sketch shows a large cliff-like back wall which gently slopes down into the tarn.
On the back wall are masses off hummocky moraine (see field sketch 4 of Hummocky Moraine, pg 9), which are gentle rolling hills which could have been shaped by a glacier moving down the land while plucking large amounts of the rock and earth with it.The sketch also shows a couple of columns of gathered earth and rock, this could be suggesting they’re ari??tes which are signs of medial moraine deposited by two glaciers that have joined together (while still flowing down the hill). The tarn implies its large water quantity could have only come from something as vast as a melted glacier. At the base of the tarn is a ridge of earth embedded with unsorted rocks- resembling a corrie lip embedded with till! All these features tied in together strongly propose they were sculpted and formed by glaciation.
My observations most definitely support that my sketch of the scene is a corrie, and the ridge at the base of the tarn is a corrie lip. Field Sketch 3: Corrie Lip Till (pg 8) Standing approximately 1. 8-2 metres tall, what seems like a cross section of the ground at the base of Easedale Tarn are loosely embedded rocks which are assumed to be Borrowdale Volcanic Granite, most of which are fairly large. Comparing the rocks to the Power’s Scale I’ve included on the sketch, most of them would be categorised into classes 2-3, which is angular/sub-angular.
This suggests that they haven’t been eroded much by flowing water, which can lead to the assumption that they are deposition of terminal moraine. This moraine would prevent a majority of the melted glacier to flow downhill, and instead form a tarn. Conclusion In my Introduction and Aims, I proposed a hypothesis that “The effect of glaciation has significantly impacted on Easedale’s current landscape”. Keeping in mind the following questions.
..In which direction did the former glacier/s flow? > What features in Easedale show some evidence that they’d been influenced by glaciers? ; Why is the Easedale Tarn located where it is? ..
while also collecting primary data through studying the location of Easedale, I find that the evidence apparent agree with my hypothesis, the effect of glaciation has significantly impacted on Easedale’s current landscape. Photos 1, 2 and 4 all show evidence of glacial features such as a back-wall, hummocky moraines, a tarn, a corrie lip (with deposited till) and a U-shaped hollow leading down Easedale Valley; these all suggest that glaciation had occurred. Photo 3 shows a roche mountonnee with features such as striations (caused by abrasion) and a steep and rugged side (caused by freeze thaw).In addition to the roche mountonnee, Rose Diagram 3 is a round graph showing the measurements of striations taken from the roche mountonnee.
This shows the general direction of the ice flow (west) which agrees with the fact that the slope of the valley is going downhill in a westerly direction, so gravity would have been carrying the glacier downhill west from where it was in Field Sketch 2. Evaluation The main purpose of the study was to see how glaciation has impacted and sculpted the landscapes of the current day; this was successfully shown through the landscape of Easedale.However, only studying Easedale has limited my knowledge of how current landscapes have been sculpted by glaciation. To resolve this problem, I’d like to study another landscape that has suggestibly been influenced by glaciation so that I can compare the two.
On the excursion at Easedale, our potential information gathered was limited due to the lack of available time. The field sketches were rushed, as were good angles for photographs. A way to avoid this problem is to extend the Easedale study to two or three days further, so that each aspect of the excursion could be more focussed on.Another degrade of the excursion was the measured striations- only one set of data was collected.
To improve the accuracy and reliability of this data, other striations on different rocks should be measured, so that the range of information gathered is broader. Another method I could carry out to improve my investigation is to compare glaciated features to other forms of landscape influences such as a river. This would support my hypothesis further as it would be cancelling out any other possibilities that could have formed the landscape.