Literature Review Of Periodicals And Theories Of Tor Formation Developed

In many ways, Geography can be categorized as a scientific subject rather than a humanities subject. This is because it tests various hypotheses by gathering data and testing theories, exactly as a practical would be carried out during a scientific experiment.

This annotated bibliography explores various sources relating to the conflicting theories of Tor formation. Monograph – Linton, D.L, (1955), The Problem of Tors, The Geographical Society Vol. 121, No. 4, Great Britain. In Linton’s monograph, he explains that tors could not possibly be formed by weathering processes but, in fact, were destroyed by them. He states that Dartmoor must have had a tropical climate during the interglacial periods of England as only warm, acidic rainwater percolating into the cracks of tors would cause severe rock rotting. Some rocks would completely rot away to leave joints between groups of rocks which would eventually form a tor when the ground level was eroded away above it.

Therefore, Linton defines a tor as a “residual mass of bedrock produced below the surface level by a phase of profound rock rotting effected by groundwater and guided by joint systems, followed by a phase of mechanical stripping of the incoherent products of chemical action” (Linton, 1955). For this reason, Linton’s monograph is a useful source of information as it is extremely detailed and expands on factual points using explicit diagrams of tor formation.

In addition, his monograph was published by The Royal Geographical Society, hence, it is evident that it has been recognized as a valuable geographic resource. The RGS is also the leading professional body for Geography across the UK and is the top ranked center for all geographical learners, regardless of level. Notably, this shows that Linton’s theory has been credited and valued by geographers all over the country which proves his work is suitable to be included in all academic pieces of work. However, Linton formulated this theory in 1955 which is over 63 years old, since then there have been more updated theories challenging that tors have formed more recently.

An example of an alternative theory was developed by J. Palmer and R.A Nielson in 1962 which suggests that the granite in tors is broken down by the action of hot magmatic gases rather than the process of deep weathering. Furthermore, new technologies have been developed since 1955 which means new theories can be proven more accurately and will be more readily accepted by today’s present geographers.

Book chapter – Smith, B.J (2012) Weathering. Holden, J (eds) An Introduction to Physical Geography and the Environment. Pearson: Harlow, Pg 186-187 This textbook gives a generalized explanation of the weathering processes that shape Tors and how the type of environment combined with the materials of the landform both contribute to the resultant weathering effects. The authors emphasize that it is easy to focus solely on the environment as being responsible for certain weathering effects whereas the materials of the landform can ultimately influence the outcome just as equally. Moreover, in some situations the materialistic properties may be increasingly distinctive meaning they become even more significant than the environmental influences. Additionally, nature’s processes can have an impact on the weathering of tors, for example, lichens that grow on granitic tors in the Namib Desert can strip away material when they dry out and lift away from the surface (Smith B. J 2012).

This book chapter describes that granitic tors can follow many different climatic pathways but essentially the outcome is always extremely similar differing only by the exact morphology of individual rocks. Besides, the formation of the Tors is usually due to the materialistic properties of the rock rather than the environment. This is proved by many indistinguishable tors being found in various climates across the world. This book chapter has a lack of bias due to it being categorized as a textbook, this is essentially an informative book rather than a specific monograph. Hence, it is designed to be factual rather than opinionated which means the reader must form their own standpoint on the information. Accordingly, this makes the source reliable by being free of uninformed statements which aren’t backed up by real research.

However, this textbook is less detailed and less specific when explaining Tor formation, it only gives a general explanation of the processes that influence them. This is because textbooks are aimed at learners with a basic level of understanding as they are used to introduce topics rather than going into greater detail for each subject. For example, this textbook was published by Pearson Education UK which is known as the “world’s learning company” showing it has a high reputation for creating educational books.

Consequently, this is disadvantageous as it might not be explanatory enough for higher academic use, but, is relevant for laying the initial foundations for geographic learning. Also, although it does contain simple diagrams and real-life pictures, it doesn’t include step by step information on the actual formation of landforms. This is disadvantageous for more in-depth academic studies on case studies or geographical processes, such as Tor formation. In summary, book chapters will always be one of the more reliable sources as they have multiple authors and are edited by credible geographers although they are less specific to individual topics which a monograph would be more suited too.

Journal article- Anderson E, Evans J.A D, Harrison S, Vieli A, (2012) Dartmoor’s overlooked glacial legacy. Geology Today, Issue 6 (Vol. 28), Blackwell Publishing Ltd, The Geologists' Association & The Geological Society of London, pg. 224-229 https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2451.2012.00855.x Once again, this journal article investigates the various theories surrounding the formation of the Dartmoor Tors. Firstly, it states that the first investigator of the Dartmoor Tors was Ransome Pickard in 1943, however, his evidence that Dartmoor was formerly glaciated was quickly disregarded by geographers due to the Linton model of 1955.

Linton’s theory was that the Tors were formed by deep weathering processes (e.g. rock rotting) during a tropical period rather than a glacial one. Conversely, there is evidence to support Pickard’s glacial theory as “glacially ‘worn boulders’ and grooved rocks, ‘moutonnée rocks’, perched boulders, moraines comprising ridges of blocky debris, and potential glacifluvial gravels” (Pickard 1843) were present in the North of Dartmoor suggesting his theory has been underestimated. Furthermore, a lot of the specifically named Tors have features that can only have happened by glacial transport, again supporting Pickard’s theory over Linton's. In closing, it is still undetermined how the Dartmoor Tors were formed as all of them are miscellaneous ages and calculating the weathering rates on them is also difficult, however, young Pleistocene bedrocks would suggest that Dartmoor was once a glacial landscape.

The reliability of this source is evidently high as the authors have researched many different theories and sources, this is shown by the mention of 3 different geographers: Linton, Pickard and Manley. By providing these conflicting theories it provides the reader with the standpoints of 3 different geographers within history. The reader can then make their own judgement on which theory is correct by analyzing the research and evidence provided in this article. For example, the article expresses that “We now understand that the occurrence of even the most delicate of landforms like tors does not automatically indicate unglaciated terrain, because glacier ice can remain largely inert or cold-based, especially beneath ice divides or dispersal centers, for prolonged periods if not the duration of glaciations. Even David Linton acknowledged this concept in his work on other upland landscapes”. This quote articulates that even the most popular Tor formation theory is questionable when faced with opposing evidence. This exhibits that the article is ideal for academic work as it has critically analyzed the different theories to make a balanced geographical argument based on the evidence provided.

Another indication this journal article is suitable for academic use is its publisher: The Geologists' Association & The Geological Society of London. These professional bodies are associated with promoting the study of geology to all geographers around the world, therefore they will always publish reliable accurate reading materials suitable for learning. Equally, the authors have provided their origin of study next to each of their names, for example, ‘David J.A Evans’ belongs to the Geography Department of Durham University so the reader can be assured that the authors are knowledgeable in this subject area.

Lastly, journals are the most reliable source of information as they have been peer reviewed. Here there are multiple authors meaning that other academics have read through this before publication checking that their claims are backed up by real evidence. In summary, this makes the journal less bias and more accurate in terms of the geographical content and case studies. News report - ScienceDaily, Durham University (2012). Ancient story of Dartmoor tors has an ice-cold twist https://www.sciencedaily.com/releases/2012/06/120613091144.htm This report outlines that glaciation may have played a bigger role in the formation of Dartmoor’s Tors than was first expected, conflicting with the renowned theories already in place. The report gives a brief explanation of how Tors are formed by deep weathering and constant freeze-thaw processes over time. Moreover, Dartmoor’s ice cap was believed to be more extensive than previous research has shown which could disapprove Linton’s popular theory of a once tropical climate. In addition, the report highlights that most Tors avoided erosion due to the ice sheets either not reaching them or having too thin a layer to induce glacial movement. This would explain why most of the Tors are still standing today and have ages dating back thousands of years.

Essentially, researchers have overlooked the minute evidence of Dartmoor’s glacial past due to the landscape being wrongly classified as a non-glacial environment. Lastly, the report quickly touches on the tourism of Dartmoor, it has become extremely popular over the last few years meaning the trust have had to limit visits to 2,400 a year. The author’s viewpoint mainly sways towards the theory that the Tors were formed by glacial processes rather than Linton’s older theory of a tropical climate. This is backed up by more recent evidence done by Durham and Exeter university showing new maps of a glacial ice sheet covering Dartmoor compared to the previous idea that the ice sheet did not extend as far as the South West.

It is hard to determine whether this news report is as reliable as the other sources because although their purpose is to inform, they have always had, and followed certain political and social agendas. However, ScienceDaily is more trustworthy than larger tabloid organizations such as ‘The Guardian’ because it is focused on an educational basis. This is because ScienceDaily has a targeted audience of learners such as professors or students. Therefore, it is paramount they source information accordingly to provide an accurate report suitable for academic use. On the other hand, this report has provided a one-sided opinion and has not evaluated both theories of Tor formation, this shows although it is a more reliable news organization, it will still spin the information to meet their own agenda.

To conclude, News reports can be reliable if they are sourced well and written by educational tabloids, however, there will always be an essence of bias in them due to certain company agendas.

Reference List:

1. https://www.pearson.com/uk/