What’s with all the hammers?

(10 geologists visiting and studying Ascension rocks)

(This article first appeared, without images, in the ‘Islander’ Newspaper in Ascension in June 2014.  Our  project is funded by The Leverhulme Trust).

Coolest UK-style road sign ever? Our friends the land crabs, no need for hammers with those claws.
Coolest UK-style road sign ever? Our friends the land crabs, no need for hammers with those claws.

Like many unexpected islands in the middle of an ocean, Ascension is here because it is volcanic. It was discovered in 1501 by a Portuguese seafarer, but since then neither passing ships nor any of the people living on the island have borne witness to an eruption. Nonetheless, Ascension owes its rugged surfaces and sloping hills to many past volcanic events, building the land over hundreds of thousands of years. It could erupt again in the future, but there are no signs or signals of a threat.

Ascension Team. L to R Ben Cohen and Fin Stuart, (SUERC); Rich Brown (Durham), Katie Preece (UEA); Katy Chamberlain and Jon Davidson -hiding in car-   (Durham); Barry Weaver (Oklahoma), me (WonderWoman stance).
Ascension Team. L to R Fin Stuart and Ben Cohen, (SUERC); Rich Brown (Durham), Katie Preece (UEA); Katy Chamberlain and Jon Davidson -hiding in car- (Durham); Barry Weaver (Oklahoma), me (WonderWoman stance). Photo taken by Charlotte Vye Brown, British Geological Survey. Anna Hicks is hiding. Attractive feature (in background) is a scoria cone.

We are a diverse team of ten researchers from the University of East Anglia, University of Durham, the British Geological Survey, the Scottish Universities Environmental Research Centre at the University of Glasgow and the University of Oklahoma (USA) visiting the island between the 23rd of June and the 11th of July.

We are interested in your volcanic island for two reasons! (1) We want to understand its volcanic activity in the past and consider what this might tell us if an eruption were to occur in the future. (2) Its fantastic assortment of rocks make it an ideal place to work on ideas about how volcanic systems build up and change over time and how this relates to the supply of magma (molten rock). The beaches and mountains of this sub-tropical volcanic island provide a unique opportunity to work on a fascinating eruption history, allowing us to develop and test new ways to understand this type of volcanic island.

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Katy Chamberlain and Ben Cohen on the edge of scoria cone. Photo taken by Charlotte Vye-Brown, British Geological Survey.
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Best ever use of a scoria cone? Lop off the top and make a fort!
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Not only scoria and lava! Pliny Duck modelling the size of the deposit informally known as the ‘Yorkshire Pumice’

To do this we are going to describe and analyse the varied types of rocks we find around the island. This will help us to try to understand the type, size and impact of the past eruptions on the island You may also see us getting our hammers out to sample some of these rocks and take them back home for further analysis. This analysis will help us date how the island built up over time, understand better what caused the magma to form below the surface and interpret what changes below the surface triggered the eruptions.

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Dramatic NE Coast of Ascension. Lavas and deposits from larger volcanic explosions. The smoky-looking band in the foreground comes from an eruption which started with one type of clast and then finished with another.

We would like to talk to many people when we are here – so if you see us out and about do feel free to stop us and ask us some more about what we are doing. We will be the ones with the rucksacks, the hammers and the red-looking faces. Of course, we’ll be sure to report back our results to those who are interested once we understand a little bit more about the fantastic geology of your island!

 

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