We've been working on this particular problem for the last year or so, but we have been working on lots of other related problems trying to figure out the tectonic history of the Earth. So really we want to understand how and why the tectonic plates, the continents, the oceans, how they have moved, where they have been through Earth's history. So this is one small piece of a much bigger puzzle of putting together Earth's tectonic history.
So here we're looking at the Pacific Ocean and the island of Hawaii. And Tawai is special because it's a hot spot and through time this hot spot has left a track of volcanoes behind Tawai which go all the way up to Kamchatka. And you can see that there is a bend here and the reason for this bend is very common controversial. People have been working on trying to figure out why the Pacific plate seems to have changed direction as it was passing over this mantle plume, this hot spot, for a very long time.
We know the age of this bend. It's about 50 million years because we have dates from rocks coming from seamounts on either side of the bend. And we now think we have solved the mystery as to why the Pacific plate changed direction at 50 million years ago. And that is that a big piece of Kamchatka, as well as what is now stuck in northern Japan, collided with that margin at 50 million years ago.
So here we're looking at seismic boat maps, which were put together by Grace Shepard. So here we're looking beneath the North Pacific and the mantle beneath the North Pacific. And this band of colors is showing us Subducted lithosphere, subducted tectonic plates from the past.
And what this is specifically telling us in the context of our story is that there was a subduction zone active here between 80 and 50 million years ago, which is exactly the time that these rocks, which we find in Kamchatka and in northern Japan, where they were located. So they were sitting on top of this subduction zone 80 to 50 million years ago. And after this time they collided, and that was why the Pacific plate changed its direction at 50 million years ago.
It's really fun. It's super exciting.