This little but impressive war memorial remembers men from the Imperial Camel Corps who served in World War One. Memorial from the United Kingdom, New Zealand, Australia and Hong Kong served in the Corps. It fought in Eygpt, Sinia and Palestine.
This EarthCache looks at the plinth of the war memorial.
🪨So, let's look at the geology of the war memorial. The war memorial is constructed from a type of rock known as limestone. Limestone is a sedimentary rock, formed by the accumulation of sediment in a shallow tropical sea, which over time formed layers of sediment, which then compacted and eventually limestone was formed. Now different sedimentary rocks have different sediment beginnings, and example of this is that sandstone is made from the accumulation of sand grains, whilst limestone is formed by the deposition of lime mud and the remains of ancient sea creatures.
Some may argue that all limestone is alike, but look a bit closer, and it soon becomes apparent that it isn't. Different depositional conditions leads to differences in limestones.
🪨 This type of limestone originates from the South West of England, more specifically Portland. It was deposited as sediment during the Jurrasic Period. The sediment originated from two ways. The sea was quite shallow, and due to this calcium carbonate precipitated in the marine environment, causing minute grains of sediment to form, which settled as lime mud. The precipitation occured due to the release of carbon dioxide into the atmosphere from the water, which then led to calcium and bicarbonate ions joining to make calcium carbonate. It all sounds very complicated doesn't it, so lets keep with this simple explanation.
Secondly the sediment settled as the remains of ancient sea creatures in the form of shells.These were broken up due to wave action and formed very small fragments to form the sediment, though many remains still are visible in the form of fossil shells.
Fossils are the remains of an animal, plant or even evidence of movement such as footprints which over millenia have become part of the rock, but you can still see part of their original structure.
Common fossils in the Portland Limestone are shells, such as oyster shells, and bivalve shells, which look like mussel shells.
🪨 The Portland Limestone firmed in layers, known as strata, and you would think that would be the end of the story, but it isn't. The layers were deposited relatively flat, though a geological event thousand of miles to the south added further words to this geological journey. The world is covered by tectonic plates, these are seperate pieces of the crust of the Earth. The African plate pushed against the European plate, which caused the Alpibe Oregeny, leading to an upward rippling of geology on the European plate, this led to the Portland limestone being pushed upwards from it's original position.
🪨Aragonite and Calcite.
When first deposited the limestone, which is basically calcium carbonate, was rich in two forms , arogonite and calcite. Arogonite is found in the shells of creatures, but is relatively not as stable chemically as calcite. When the limestone was uplifted by the Alpine Oregeny, it then meant the rock was exposed to surface water, such as rain. Limestone is porous, this means that water easily absorbs through it. During the process of the water percolating through the limestone, it leached the arogonite out of the limestone. This meant that many fossils actually dissolved, and in some cases voids were left, and in others the shells just dissapeared. Now, you may ask why you can find oyster shell fossils in Portland Limestone. Well oyster shells have a high concentration of calcite, deposited in layers, which made them relatively more resistant to the leaching process.
This being an EarthCache, in order to log it, I ask that you complete the above tasks. Please send the answers to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
1. Please look at the pedestal, is there any evidence of any arogonite leaching?
2. On what aspect of the memorial can you find the most oyster shell fossils, why are they still apparent in the limestone? In terms of describing the aspects of the memorial, please use the following:
Front of Camel.
Back of Camel.
Two running soldiers side.
Soldier sat on camel side.
3. What type of rock is Portland limestone?
4. Please have your photograph taken next to the nearby Robert Burns memorial, or if you prefer you could take a picture of your device.
If anybody would like to expand to this series please do, I would just ask that you could let Just-Us-Two know first at justustwo1013@gmail.com so they can keep track of the memorial numbers and names to avoid any duplication.