Archive for februari, 2013

PUMICE ROCKS IN SOUTHERN PACIFIC

söndag, februari 10th, 2013

 

For a while ago a volcanologiest from Dunedin in New zealand contact me after seen my blog about the ”Tonga to New zealand crossing”. He was very curious about the pumice rocks we picked up and got washed up on Misty during the sailing. Big fields of pumice rocks was floating around us during most of the crossing. All sizes from very small, up to the size of a coconut. I sent a bunch of samples to the volcanologiest and he later replied:

”The rafts you saw were products of a large under water eruption, at Le Havre seamount, in July 2012. I am tracking the still-floating rafts with satellite images; it works pretty well, but only for large rafts, so it is important to know when the first pumice arrived at Tonga, or whether any pumices arrived to NZ coasts, for example. You can get information about the eruption at:

http://www.nzherald.co.nz/nz/news/article.cfm?c http://www.wired.com/wiredscience/2012/08/source-of-kermadec-island-pumice-raft-eruption-identified/_id=1&objectid=10843153

The fate of the pumice clasts is either to progressively water log and sink on the sea floor, or to be sedimented on a beach somewhere around the world. It can take motnhs for the pumice to absorb enough water to sink, so they can travel a fair way – they are pretty amazing things, and were very lucky to cross a raft – there are only a couple of them every decade around the world, and usually coming from eruptions in shallow water. This one was from a deep eruption, which is strange. I will let you know if anything is published from my side” / Martin Jutzeler.

If I have had known that these pumice rocks were so important for some scientists, I had collect buckets of them!