The Nelson area (Nelson and Tasman) boasts some of the most varied geology in New Zealand. The area contains some of the oldest rocks in the country, found in the west and consisting mainly of sandstones and siltstones formed in the Cambrian period over 500 million years ago.
The Nelson area is built of a complex series of igneous, volcanic and sedimentary rocks. The landscape has been shaped by seismic activity occurring over millions of years as the Australian and Pacific tectonic plates push against each other. Its landscape has been shaped by erosion and deposition by glaciers, rivers, the sea, and wind.
There is a wide variety of rocks and minerals in the area. Serpentine, coal, dolomite, limestone, marble, granite, schist to name a few. Dun mountain and the Red Hills contain such high nickel and magnesium content that the growth of vegetation is inhibited. In other areas the presence of minerals has meant that vegetation is significantly stunted.
Many of the rocks and minerals of the Nelson area have economic value. Rich, though localised, reserves of gold, chromium and copper were all found, mainly in association with zones of mineralisation in older rocks. Many of these were extensively exploited during the nineteenth and early twentieth centuries, and the remains of these endeavours are widely scattered across the region. They often tell a story of huge hardship as miners tried to win the minerals from the land - and brief success before the resources ran out and mining ceased.
Iron was extracted at Onekaka in Golden Bay.
In other parts of the world, rock is used extensively in building. There are some stone buildings around Nelson but earthquakes somewhat dissuaded the use of rock in New Zealand, besides which, timber was much more accessible and easier to transport.
Rock has been used in the building of roads and walls, for statues and steps and for jetties. Māori used stone to make tools such as adzes, chisels and knives for carving and cutting wood, fish hooks, hammer stones and points for spears. Large rocks were used as anchor stones. You will see a rock that was once an anchor stone at one of the waypoints.
Patterned rock has been used for making jewellery.
In New Zealand you will see touchstones or whaihua in the entrance to buildings to celebrate the connection between the building, the land and the tangata whenua (people of the land). It is said that the wairua or spirit of the stone protects traditional Māori values.
Do touch the rocks you study today to establish a connection with them and where they come from.
Examples of Nelson Rock:
To claim this earthcache you will need to visit each of the listed waypoints which are on or near Trafalgar Street, Nelson. At each waypoint, describe what you see, and what type of rock has been used. Please make sure you number your answers carefully.
Please send the answers to me using the Message centre. As soon as you have sent the answers, go ahead and log the cache. Do not wait for a reply, I will let you know if there are major problems with your answers.
If you are able to include photos with your log, that would be really appreciated, but please don't include anything that will assist others to answer the questions.
Enjoy your visit.