The Lakes of Rotorua
Rotorua lies within the Taupo Volcanic Zone, a highly active volcanic area in the North Island. The zone is approximately 350 kilometres long by 50 kilometres wide, stretching from Mount Ruapehu at the southwest end and beyond White Island to the submarine Whakatane volcano at the northeast end. The zone is rich in geothermal features (hot springs, geysers, fumaroles, and mud pots) and evidence of volcanic activity. Some of this evidence includes the many lakes to be found in the Rotorua area, most of which are calderas formed from rhyolitic (igneous rock rich in silica) eruptions.
The Green and Blue Lakes
The Green and Blue Lakes (Maori names Lake Rotokakahi and Lake Tikitapu) sit side by side and were formed at a similar time, however their colour difference is notable. This difference can be attributed to the different soils on each lakebed.
The larger (440 ha) Lake Rotokakahi / Green Lake, is a collapsed volcanic crater, and looks green because it is relatively shallow (32m) and has a sandy bottom. This lake flows into Lake Tarawera via Te Wairoa stream.
The smaller (150 ha) Lake Tikitapu / Blue Lake, also relatively shallow (27.5m), gets its blue colour from reflection from the white rhyolite and pumice lakebed. This lake has no surface outlet but drains via underground to Lake Rotokakahi.
In Maori Rotokakahi means the lake of the shellfish "kakahi". The lake is sacred to Maori and privately owned by local iwi (tribes), no swimming, fishing or boating is permitted. Tikitapu, named as the place where the daughter of a high born chief lost her sacred greenstone neck ornament (Tikitapu), is a great place to go for a swim or take the boat out. The track around the Blue Lake (5.5km / 1.5hours) is also a lovely walk.
The Earth Cache
To complete this earth cache please email me the answers to the following questions (include your username and the name of this cache). Please do not post answers in your log but feel free to add a picture of yourself, your GPS or a view of the lakes. You may log your find as soon as you have emailed the answers to me i.e. you do not need to wait for permission. I will be checking logs and email you if there is a problem. Please no cheating it just spoils it!
Question 1. How many years ago where these lakes formed?
Question 2. From the lookout point you can see both lakes, estimate the distance between them?
Question 3. On a clear day the colour difference is obvious. Describe in your own words the colours you can see and how the weather was at the time of your visit?
Please enjoy and respect the area. Happy Earth Caching!