Map of Observations
Map by J. Paton
Our project for the qualifying expedition to the Isle of Arran was the analysis of the geography and ecology of the island. Throughout the duration of the expedition, we marked and noted on our maps the locations of all geographical features along with the locations of any animal sightings. Although we were quite unfortunate on the variety of the number of animals that were sighted, it is undeniable that the geography of the Isle of Arran was beautiful.There was clear evidence for the glacier that used to exist on the island and is clear to say that the geographical features are quite remarkable.
Cirque/Corrie: This is armchair-shaped feature is sculpted when a glacier starts to form. A crack in a rock is exploited as it fills with snow, and this snow then turns into ice. The consequent freeze-thaw weathering deepens this crack in the rock into a larger hollow. The steep wall is caused due to the ice plucking the back of the slope, and a curved dip is present at the bottom. Erosion occurs most in this dip, as this rock has the largest weight of ice above it. The sheer weight of the ice, leads to pressures high enough to melt the ice at the bottom, which only augments the rate of erosion as basal sliding can occur (the sliding of rocks at the base, which leads to abrasion). However, after the dip the rate of erosion decreases, and this leads to the formation of a rock lip.
Tarn: A lake that forms in a corrie once the glacier has melted.
Pyramidal Peak: This is Goatfell, Arran’s tallest mountain. It is in fact a pyramidal peak, which is the result of three corries forming around each other, resulting in the sharp pinnacle.
U-Shaped Valley: A U-shaped valley is formed when a glacier bulldozes its way down a slope, and carving out the land by scouring. The steep sides of the U-shaped Valley are called truncated spurs. If water flows through a hanging valley it will crash into the larger valley as a waterfall. A river that flows within a U-shaped valley is called a misfit river.
Hanging Valley: These form when smaller tributary glaciers join a larger one.
Raised Coastline: A raised coastline can be seen widely on the West Coast of Scotland, and the same can be said about Arran’s coast. This raised coastline is a result of the end of the Ice Age, in which the glaciers on Arran started to melt. This reduced the weight on the Arran Rock, causing it to rise upwards.
Devonian Sandstone: This deep-red sandstone forms part of the country rock of Arran.
Arran Granite: Due to the volcanic activity in Arran 60 million years ago, Arran is made up of some very impressive igneous rock formations. The largest being, the granite itself on the North of the Island. This entire structure is called a batholith, and is the result of a diapir of magma cooling beneath the Earth’s Crust, that later emerged onto land.
Chilled Margin: This is caused at the border of the igneous intrusion with the sedimentary country rock (The country
rock is Sandstone in Arran). When the hot magma cools to form the igneous rock, it heats thesurrounding country rock so that is has a more crystalline structure; this strengthens the country rock, making it more resistant to erosion and weathering. This harder country rock is called the Baked Margin. Conversely, the surrounding country rock increases the rate of cooling of the periphery of the igneous rock; this is called the Chilled Margin. Due to the rapid cooling at the chilled margin, this rock develops cracks and weaknesses (cooling joints), making this rock more vulnerable to weathering. Hence, we can see a ‘dip’ in the side of the rock, indicating the presence of a chilled margin that has eroded faster than the surrounding rock.
Dykes: Dykes are another type of an intrusive igneous formation. They form when magma exploits weaknesses in the layers of sedimentary rock. They are described as discordant as they penetrate through multiple layers of rock (opposed to sills which are described as concordant as they form between layers of sedimentary rock). The dyke also has chilled and baked Margins. The top surface of the rock in the picture is the chilled margin, which is more vulnerable to erosion and weathering due to its cooling joints.
Sill: A sill formed on the side of the mountain. Sills are very similar to dykes, but instead of exploiting weaknesses within layers of sedimentary rock, they exploit weaknesses between layers of sedimentary rock, and thus they are called concordant. The sill here is the rectangular layer of granite on the right of the image, that formed on top of the Devonian Sandstone (which can be seen to the left and below the granite).
Hutton’s Unconformity: James Hutton, the father of modern geology, noticed on Arran an unconformity between strata of Devonian Sandstone and Neopro Dalradian; the strata formed in the same area, but were slanted in different directions. This shows that the rocks where formed at different times and by different forces, which opposed the theories of the time, and led Hutton to theories about the age of the Earth (that the Earth is millions and not thousands of years old) and uniformitarianism (that present day scientific phenomena are the same as those in the past). Both these ideas were revolutionary considering that they went beyond ideas based on Biblical descriptions.
During our time at Arran we were lucky enough to see many different land animals. A common animal we saw was seals. There are two types of seals present on Arran, the common seal and the grey seal. We can distinguish between them as grey seals have longer snouts as well as far apart nostrils. Seals were present along the coastline but is most common at Lochranza which is known as the “Loch of seals.” Another animal we encountered was the red deer. It is known for being the largest mammal in the UK. We can identify red deer through their dark russet-brown fur with a paler buff rump and a pale tail. Breeding season is usually during autumn and is known as the ‘rut’. During this males claim their territory and will fight over the females. Red deer live on moorland and mountainsides as well as grasslands. Another animal we found was a common shrew. A shrew is a small mammal with small eyes and a large nose meaning it has a very good sense of smell. They are found in most habitats and feed on earthworms, spiders and chrysalises. They are commonly known for being territorial and aggressive despite their size.
On day 2 of our expedition at the coast of arran near Lochranza we saw both types of seals the common seal and the grey seals. On that particular day the tide was low meaning it was the perfect conditions to see the seals in their natural habitats. As we were walking along the coast, we saw seven common seals lying across the rock beach. This was expected as common seals or harbour seals tend to travel in packs.
Later on, in the day we then saw a single grey seal in the water bobbing its head up and down. Due to the behaviour of the seal it can be said that it was hunting most likely for its prey which are crustaceans, small fish or squid. The way we were able to distinguish this seal we saw from the other seals was the snout. This is because grey seals have longer snouts then the common seals.
Isle of Arran had many birds; we spotted many with our knowledge we prepared with before heading up to the island. We spotted many birds near the coast of the island; kestrels, buzzards, sparrowhawks and others, but had no luck with spotting an eagle. There were many birds that were spotted throughout our treks, but these usually tended to be kestrels or buzzards. Raptors were also seen throughout the island. Near the coast and in the sea, there were birds which dived straight into the water – these were spotted on the ferry trip and on day 2, on which we handrailed the coast of the island. We didn’t spot many flocks of birds as the birds on the island usually are solitary. The kestrels made a very loud, recognisable call and were noticeable when we could not even see the bird. Other birds, such as buzzards also made calls and noises but these were not as loud as the ones we heard from the kestrels throughout our journey.
When searching for the endemic flora species on the Isle of Arran we found: the Arran whitebeam (Sorbus arranenesis) on day 4 in Stronach Woods and the cut-leaved whitebeam on day 1 in Lochranza (Sorbus psuedofennica). These species are distinctive as they grow low to the ground and are multi-stemmed due to the harsh weather and overgrazing respectively; they do not flower or fruit which narrowed the search. Whitebeam on Arran are rare and critically endangered e.g. the catacol whitebeam (Sorbus pseudomeinichii) with only a couple trees still standing (this being the most severe example).
R Code For Map
airdata = read.csv(“Air.csv”)
seadata = read.csv(“Sea.csv”)
landdata = read.csv(“Land.csv”)
floradata = read.csv(“Flora.csv”)
geogdata = read.csv(“Geography.csv”)
campdata = read.csv(“Camp.csv”)
#creates various icons
arran_icons <- awesomeIconList(
Air <- makeAwesomeIcon(icon = ‘cloud’, markerColor = ‘gray’, library = ‘glyphicon’),
Land <- makeAwesomeIcon(icon = ‘paw’, markerColor = ‘green’, library = ‘fa’),
Sea <- makeAwesomeIcon(icon = ‘tint’, markerColor = ‘blue’, library = ‘fa’),
Flora <- makeAwesomeIcon(icon = ‘pagelines’, markerColor = ‘pink’, library = ‘fa’),
Geog <- makeAwesomeIcon(icon = ‘caret-up’, markerColor = ‘red’, library = ‘fa’),
Camp <- makeAwesomeIcon(icon = ‘map’, markerColor = ‘white’, library = ‘fa’)
addAwesomeMarkers(lng = airdata$Longitude, lat = airdata$Latitude, group = “Air”, icon = Air, label = airdata$Species) %>%
addAwesomeMarkers(lng = seadata$Longitude, lat = seadata$Latitude, group = “Sea”, icon = Sea, label = seadata$Species) %>%
addAwesomeMarkers(lng = landdata$Longitude, lat = landdata$Latitude, group = “Land”, icon = Land, label = landdata$Species) %>%
addAwesomeMarkers(lng = floradata$Longitude, lat = floradata$Latitude, group = “Flora”, icon = Flora, label = floradata$Species) %>%
addAwesomeMarkers(lng = geogdata$Longitude, lat = geogdata$Latitude, group = “Geographical Interest”, icon = Geog, label = geogdata$Species) %>%
addAwesomeMarkers(lng = campdata$Longitude, lat = campdata$Latitude, group = “Campsites”, icon = Camp, label = campdata$Species) %>%
baseGroups = (“OSM”),
overlayGroups = c(“Air”, “Sea”, “Land”, “Flora”, “Geographical Interest”, “Campsites”),
options = layersControlOptions(collapsed = TRUE)) %>%
Webpage and photos by J. Paton