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Francis Rawdon Moira Crozier
1796 – c.1848
Born in Banbridge, Crozier is best known as the second-in-command of the ill-fated Franklin expedition to find the Northwest Passage. However, the tragic disappearance has overshadowed his numerous achievements. Over the course of more than 35 years with the Royal Navy, Crozier took part in five other expeditions and was an experienced polar explorer recognised for his scientific achievements.
The monument in Banbridge was erected following the mysterous disappearance of the Franklin Expedition and the protracted search to discover its fate. It's a fine construction featuring decorative polar bears and inset panels with inscriptions and illustrative carvings, below a plinth with full-length statue. The majority of the memorial is constructed from sedimentary rocks.
Questions
Please submit the answers to the below questions via the message centre. You may find the information on this page helpful when considering your answers.
1. The main body of the memorial is made of limestone. Describe the colour, texture, etc of the rock.
2. On the faces of the memorial are four inset panels. They are made from different stone to the main memorial. Describe them. What types of rock do you think they might be?
3. Why do you think the different rock types were selected for these panels?
4. In your own words, how are sedimentary rocks formed?
5. Please include in your log a photograph of an item which is identifiably yours at the memorial. The photo doesn’t have to include your face – your GPS, your geopet, a card with your caching name and date of visit…
If no answers are received within a week, your log may be deleted.
Sedimentary Rocks
Sedimentary rocks are formed from deposits that accumulate on the Earth's surface. These deposits can be made from inorganic materials such as sand and mud, or organic materials such as shells. As the deposits build up over time they can show distinctive layers. These layers are one of the features which distinguishes sedimentary rocks from igneous and metamorphic varieties. The layers which are lower down become cemented together to form rock as chemical ions precipitate out of groundwater and stick the sediment grains together. Tectonic upheavals can then bring the rocks to the Earth’s surface.
Sedimentary rocks are frequently used in construction. When used in buildings, some of the features that can be observed are their colour and composition. The bedding in the rock is frequently visible as stripes of colour and texture, which may have varying thicknesses and angles. This can show how the sediment was deposited and whether the rock has been eroded or deformed by techtonic forces. The colour of the rock is associated with its chemical make-up and how it reacts to weathering. Green or orange reduction spots can be a startling feature caused by forms of iron being oxidised.
It’s easy to see why sandstone has its name. This type of rock is characterised by larger grains which resemble beach sand. They can usually be seen without special equipment. By studying the features, it's often possible to determine the environment in which the sediment was deposited and the process by which this occured. Sandstones come in many colours and frequently have a rough texture reminiscent of the sand which formed them. This structure makes them easy to work with, but also leaves them susceptible to weathering.
Unlike sandstones, mudstones are made up of particles too small to be seen with the naked eye. They are formed from deposits of muds and silts. This produces a smooth texture capable of holding fine details when worked. Slate is often thought to be a typical example of a mudstone, although it has undergone a small degree of metamorphism. The bedrock of County Down is largely made up of mudstones from the Silurian era (approximately 440 million years ago). The rock is contiguous with that which forms the uplands of southern Scotland and Northern England.
Unlike the previous sedimentary rocks, which are predominantly made up from inorganic deposits, limestone is composed of shells and other organic material. Many limestones are formed by the deposition of sediments rich in carbonate. Others are formed through the growth of coral reefs and microbial mats. As a result it often contains fossils of marine creatures such as shellfish and corals. Limestone is a variable rock, as it can be a number of different colours depending on the conditions under which it was formed. Where the carbonate is very pure, the rock is a pale grey or white colour. Dark grey or black limestones have a higher amount of carbon, while pinkish and reddish ones contain more iron. Limestone makes up a large proportion of the bedrock of Ireland.