Baby Rocks

As a geologist I'm fairly used to dealing with rocks that are millions, or hundreds of millions, and occasionally billions (I have held the hand-sample of the Jack Hills Conglomerate which contains the oldest minerals on Earth at 4.4 billion years old but thats another story!). But things on Hawaii are a little younger.

This is the youngest lava flow on Maui, known as the 1790 flow, because the maps of the island made in 1791 were different from those made by Captain Cook in the 1770s. It might actually be older than that, the maps may not be accurate.  But it was around then.

For the second part of the trip we moved on from the dormant volcano of Maui and onto the active volcanic island of Hawaii, also known as Big Island, when distinction is needed between the island and the chain of islands. We went to Kilauea volcano, the most active volcano on earth (unfortunately not spewing lava when we went) which have baby rocks (note: not a technical term), some only a few weeks old.  All together now: awwwwwww.

Hawaii is a shield volcano.  As the lava is so runny you don't get the iconic cone shapes that build up on more stereotypical volcanoes.  And they tend to erupt for longer periods of time.  As a result the lava spreads out over large distances, forming a shield shape.  This can mean that, in places the volcano isn't that tall and is relatively flat.  Kilauea is a bit like that, dwarfed by Mauna Loa and Mauna Kea above it which have built up higher as they are older volcanoes. This means its possible to cycle around Kilaeau National Park and go and see the sights by bike, rather than trapse around by car.  It was a well needed break from the car, and meant we got to on some of the tracks round the park where cars can't go and had some of the park to ourselves. Especially when we came across this on a lava flow that dates to just 1973 (or so).

 Its a volcano monitoring station. With super-accurate GPS units, gas monitoring, tilt-metres and the like, all designed to measure tiny changes in the volcano's shape and output that give little clues as to location and movement of magma deep below the ground.  This is how geologists predict eruptions!

Of course there are some parts of the park where you can't go.  Some due to current or potential volcanic activity, others because of past activity:

 I'm used to road cuts through rock providing useful geological outcrops.  But here the rock has revenge, the 1973 lava flow has reached the road here, and behind it has completely covered it over. How cool is that?!

 In the background above is the 1973 flow, in the foreground, part of the 1969 flow.  The crack running down the left with the trees next to it is the fissure from which the lava erupted.

 Me above the fissure!

 More views of recent lava flows

 The 1973 flow, barren, rocky, almost alien, but very very cool!