In January 2025, we traveled to the Canary Islands for a brand new type of fieldwork (for me, anyway). PhD student Jadie Sauerbier, under supervision of Lydian Boschman and me, and our friend Yamirka Rojas-Agramonte, aims to find an efficient way to date the emergence of volcanic islands, and the arrest of volcanism on such islands, which form important but poorly known parameters in the understanding of island biodiversity and evolutionary biology. So we went to the Canary Islands – a series of well-dated hotspot volcanic islands in the Atlantic Ocean offshore Morocco, to see if we can reproduce the ages in just a few days of sampling. Nature has been so friendly to erode the volcanoes and bring the minerals that we can date in them – especially zircon, but also apatite or titanite – through rivers to the beaches, where they become enriched in the sand due to natural ‘gold panning’: the heavy minerals stay behind on the beach, and the lighter ones are brought to sea. We collected samples from beaches and rivers – about 15 kg per sample – and then did mineral separation by panning on the beach. In the end, we only brought a few hundred grams of heavy mineral extract back to the lab, where we will test whether we can date the volcanoes, and how bad contamination by wind, or human activity is. Below a field impression!
Jadie Sauerbier, PhD student at Utrecht University
Lydian Boschman, assistant professor at Utrecht University
Yamirka Rojas-Agramonte, our Cuban friend from the University of Heidelberg, and a specialist in zircon dating AND the master of heavy mineral panning!
…and meThe Canary Islands are a roughly E-W trending series of hotspot volcanoes. We sampled Fuerteventura, Gran Canaria, and Tenerife, and Jadie continued to also sample La Gomera and La Palma, farther west.There is not a large population on Fuerteventura, and most beaches are deserted. Here, there was some occupation, and we sampled to see if this pollutes the zircon population in the beach sand.Jadie, sampling. Or playing on the beach, but that’s almost the same.Yamirka and Lydian, collecting samples, early in the morning.The beach sands consist of volcanic minerals, as well as of limestone fragments of sea life. The wind has done some mineral separation here: on the windward side, the darker and denser volcanic minerals are concentrated, on the leeward side of the small dunes there’s the lighter limestone fragments.We didn’t just sample the beaches, but also went closer to the source. This cinder cone on Fuerteventura did not yield any fine sand that we needed though……but the rivers sure did! Here, Yamirka is digging up some fine sand fraction in a dry river bed on Fuerteventura
The limestones come in funny shapes on Fuerteventura. This ‘natural popcorn’ is made of rodolith, which is made by algea.
The beaches do not just have sand! There’s all sorts of nice volcanic goodies, such as dykes cutting older volcanic deposits
Or peperite! Mixtures of basalt and sediments that form when lavas flow over sand.
Lydian, Yamirka, and Jadie, collecting samplesAnd bringing them to the panning location!
Next stop: panning! Here, Yamirka & I are working on it in the surf
Yamirka, Jadie, and Lydian, using the pan to isolate the heavy mineral fraction
Lydian, panning olivine sandBags of sample, ready for separation
Yami, Jadie, and I at work on Gran Canaria
Gran Canaria is a lot higher and more rugged than Fuerteventura
And a lot greener, too!
With some amazing beaches!Beautiful dark olivine sandsSampled by YamiFuerteventura coast with the island of Lanzarote in the background
Beautiful tree on Gran Canaria, looking out over the river valley
Lydian and Jadie on their way to an early morning sample collection
Me, panning in the surf
Pleistocene fossils
Lydian and I, panning
Good moods, all around!Beautiful scenery, on Gran CanariaThis was great, and there’s a lot more of these islands that we hope to go to. I can get used to this kind of fieldwork 😀