EOSC 311: Geoscape Project: Auckland, New Zealand

Auckland’s freshwater comes from dams, rivers and underground aquifers in the region. Contaminants such as debris and micro-organisms are present in this water, and thus needs to be filtered at treatment facilities prior to consumption. Auckland is beginning to have issues surrounding it’s freshwater – which has turned into a nationwide debate. As with any growing, metropolitan city, urban waterways are contaminated by the cities’ expansion. Rural land use practices, power generation and general pollution are driving factors in the issue. After a particularly bad storm in 2017 dubbed the ‘Tasmanian Tempest’, the Ardmore treatment plant stopped working for a short period and then functioned at low capacity when landslips and silt clogged the filters. The mass amounts of silt were due to deforestation in the Hunua Ranges – without forests to hold the earth together, soil washed into reservoirs. The water plant has since been upgraded so that it has a higher resilience to these...

Due to tectonic plate activity and subducting plates, volcanic activity is also common in the history and current state in New Zealand. There is a large volcanic zone, known as the Taupo Volcanic Zone on the North Island. As the Australian plate has stretched, it’s crust has become thinner than normal. Molten rock easily rises to the surface and through the thin crust and has erupted from volcanoes such as Ruapehu or Tongariro, or sits within the crust, heating it and water up, causing geothermal activity near Taupo and Rotorua. The city of Auckland sits on a volcanic field – known as the Auckland Volcanic Field with over 50 volcanos in an area of ~1000 square kilometers, which forms the hills, lakes and basins of the city. These volcanoes are fed by one magma source – a diffuse pool, occasionally finding its way to the surface, erupting in a different place each time. While the area is thought to be dormant as it is unlikely that the magma will push through the same place twic...

The Geologic history of New Zealand can be broken up into 6 stages: 3 sedimentation periods and 3 mountain building periods. 1. The early sedimentation depositional phase, Cambrian to Devonian period (about 545 to 370 million years) Earliest rock formations in new Zealand found today on South Island. At the time, New Zealand sat just off the ancient mega-continent of Gondwana. This included the formation of volcanic islands, which were eventually covered in sand and mud, subsequent land uplifting and erosion. 2. The Tuhua Orogeny, late Devonian to Carboniferous period (about 370 to 330 million years ago) Pressure and uplift characterized this period – which formed mountains with new minerals under great heat and pressure. These mountains were eventually eroded and covered by younger materials.   For example, sandstone and mudstone became schist, known for parallel layering of minerals like mica. Plutonic intrusions formed granite and diorite. 3. The New Zealand...

New Zealand is located at a subduction zone. Under the North Island (where Auckland is located), the Pacific plate is being subducted underneath the Australian plate. In contrast, the under the South Island, the Australian plate is being subducted under the Pacific plate. A major feature of the South Island is the Alpine fault, which forms the boundary between these two plates. This is a strike-slip fault (plates move side by side), and a large mountain region is located at the fault, uplifting slightly each year. With these tectonic features in mind, Auckland is susceptible to a variety of geological hazards, including but not limited to: slope instability, seismic, volcanic and tsunami hazards. The movement of these plates means that Auckland and New Zealand in general is greatly at risk of earthquakes.   In addition, there is also a long history of volcanic activity in this area due to subducting plates. In fact, Auckland sits on one of the most densely packed volca...

Torlesse supergroup Murihiku supergroup Alpine Fault Geothermal Energy Auckland Volcanic Field Taupo Volcanic Zone