Kaikoura - where the mountains meeting the sea
The subject of this earthcache are two fossils sourced locally and housed in the Kaikoura museum
The Southern Alps were created during a time of huge uplift which has been called the Kaikoura Orogeny. The creation of the Alps was an internal process caused by the collision of the Australian and Pacific tectonic plates.
25 to 15 million years ago the majority of New Zealand was covered by the ocean. As the Australian and Pacific tectonic plates began to collide with each the New Zealand crust came under pressure and the Alpine Fault was created. This fault line runs along the western edge of the Southern Alps. This event, or prolonged period of earth movement, which is still going on today, slowly pushed up the Kaikoura mountains and the surrounding landform up out of the ocean. In total about 20 kilometres of uplift has taken place during the Kaikoura Orogeny but most of this has been eroded away.
With time and the steady erosion of the hills, the concretions were ultimately exposed high on the cliff face at Tarapuhi, near Amuri Bluff. Eventually, this concretion let go and rolled down the steep face to crash on the rocky beach below, where it split in two like an apple, exposing in its centre the fossilised bones of two marine reptiles. The fossils in the museum are but a small portion of the reptiles that are thought to be about 12 metres in length. These are the fossil remains of a Mauisaurus haasti and a Taniwhasaurus oweni that frequented the southern seas. They belonged to a larger group of marine reptiles that roamed the oceans at the same time as the dinosaur inhabited the land in the late Cretaceous period that extended over 77 to 78 million years ago. Mauisaurus gets its name from the New Zealand Māori mythological demigod, Māui. Māui is said to have pulled New Zealand up from the seabed using a fish hook, thus creating the country. Thus, Mauisaurus means "Māui reptile". Mauisaurus gets its scientific last name from its original finder, Julius Haast, who found the first Mauisaurus fossil in 1870. The specimen was then first described in 1874. Taniwhasaurus oweni, the type species for Taniwhasaurus, was named by Hector in 1874 from a fossil specimen found in the late Campanian Conway Formation outcrops at Haumuri Bluff. The plesiosaur and mosasaur, along with the dinosaur and several other species, became extinct when the earth was overcome by some great catastrophe, thought to be a large meteorite striking the earth. This is said to have created violent dust storms that completely enveloped the planet, plunging it into a prolonged period of darkness. That, in turn, caused a rapid drop in temperature, which, it is thought, they could not tolerate. About 77 million years ago, our two marine reptiles were unable to survive and sank into the mud on the sea floor to become the nucleus of the concretion you see here today. Large round rocks slowly developed around the bones in the mud.
To log this Earth Cache, please send us the answers to the following:
1. Who found the first Mauisaurus fossil and what year ?
2. How many teeth have the fossil remain on display?
3. What was the probable course which wiped out the plesiosaur and mosasaur from the Earth ?
There is an entry fee of $12 for Adult and $6 for a kid.
Enjoy your Kaikoura visit
.