Fossils survive volcanic eruption to tell us about the origin of the Canary Islands

January 22, 2015, Uppsala University

The most recent eruption on the Canary Islands – at El Hierro in 2011 – produced spectacularly enigmatic white "floating rocks" that originated from the layers of oceanic sedimentary rock underneath the island. An international team of researchers, led from Uppsala University, use microscopic fossils found in the rocks to shed new light on the long-standing puzzle about the origin of the Canary Islands.

Despite being violently transported through the volcano, some of the rocks produced by the El Hierro eruption contain of delicate single-celled marine organisms, making the survival of these fossils all the more extraordinary.

A new study published today in Scientific Reports, an open access journal of the Nature Publishing Group, by a team of scientists from the universities of Uppsala, Las Palmas de Gran Canaria, Lisbon, and the Research Council of Spain, uses these fossil time-travellers to date the sedimentary layers beneath El Hierro and, in turn, shed new light on the long-standing puzzle about the origin of the Canary Islands.

The origin and life cycle of oceanic volcanoes, such as the Canary Islands, has long been a source of debate among natural scientists. There are two competing models for the origin of the Canaries – one in which ocean floor fractures control the location of volcanic activity, and another in which an anomalously hot plume of molten rock from the Earth's mantle feeds island growth from below.

A cornerstone of the debate concerns the validity of an age-progression along the island chain. A fixed mantle plume under the roughly eastwards moving African tectonic plate would cause the islands and the pre-volcanic ocean sediments underlying them to become progressively younger towards the westernmost island of El Hierro. The fracture model, in turn, would give rise to randomly distributed island ages.

"Fossils and volcanoes are not usually compatible with each other, which is what makes these samples so special," says Valentin Troll, professor at the Department of Earth Sciences at Uppsala University, who led the study that is now being published in Scientific Reports.

The study offers a unique perspective on the plume versus fracture model debate for the origin of the Canary Islands. The fossils are de facto witnesses of the pre-island environment. Researchers can now place constraints on the ages of the sedimentary strata present before island-building and, indeed, on the initiation of island-building itself. In combination with known sediment ages from the east of the archipelago, it is now clear that the oceanic sediments become younger towards the west of the island chain, thus verifying an age-progression among the islands. These findings are in strong agreement with the model for the of the Canary Islands and thus contribute to our wider understanding of ocean island volcano genesis.

Explore further: Seismic activity felt on Spanish volcanic island

More information: Zaczek, K., Troll, V. R., Cachao, M., Ferreira, J., Deegan, F.M., Carracedo, J.C., Soler, V., Meade, F.C., Burchardt, S. 2015. "Nannofossils in 2011 El Hierro eruptive products reinstate plume model for Canary Islands." Scientific Reports 5:7945. DOI: 10.1038/srep07945.

Related Stories

Seismic activity felt on Spanish volcanic island

December 23, 2013

Spain's National Geographical Institute says the Canary Island of El Hierro has been rocked by more than 50 tremors in 24 hours, two years after a new volcano began to appear off its southern coast.

Uranium isotopes reveal age and origin of volcanic rocks

January 20, 2015

From the beginning of time, uranium has been part of the Earth and, thanks to its long-lived radioactivity, it has proven ideal to date geological processes and deduce Earth's evolution. Natural uranium consists of two long-lived ...

Source of Galapagos eruptions is not where models place it

January 21, 2014

Images gathered by University of Oregon scientists using seismic waves penetrating to a depth of 300 kilometers (almost 200 miles) report the discovery of an anomaly that likely is the volcanic mantle plume of the Galapagos ...

Spanish island to be fully powered by wind, water

April 28, 2014

The smallest and least known of Spain's Canary Islands, El Hierro, is making a splash by becoming the first island in the world fully energy self-sufficient through combined water and wind power.

Recommended for you

The powerful meteor that no one saw (except satellites)

March 19, 2019

At precisely 11:48 am on December 18, 2018, a large space rock heading straight for Earth at a speed of 19 miles per second exploded into a vast ball of fire as it entered the atmosphere, 15.9 miles above the Bering Sea.

Revealing the rules behind virus scaffold construction

March 19, 2019

A team of researchers including Northwestern Engineering faculty has expanded the understanding of how virus shells self-assemble, an important step toward developing techniques that use viruses as vehicles to deliver targeted ...

OSIRIS-REx reveals asteroid Bennu has big surprises

March 19, 2019

A NASA spacecraft that will return a sample of a near-Earth asteroid named Bennu to Earth in 2023 made the first-ever close-up observations of particle plumes erupting from an asteroid's surface. Bennu also revealed itself ...

Nanoscale Lamb wave-driven motors in nonliquid environments

March 19, 2019

Light driven movement is challenging in nonliquid environments as micro-sized objects can experience strong dry adhesion to contact surfaces and resist movement. In a recent study, Jinsheng Lu and co-workers at the College ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

FionaMeade
5 / 5 (1) Jan 24, 2015
Thanks for covering our paper! There has been much debate on the origin of these floating rocks and it's great to be able to present such conclusive evidence of their sedimentary origin. The paper is open access and so free for all to download and read from the Scientific Reports website.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.