An Icelandic Sedimentary Sequence – the Tjornes Pliocene Beds

While I am in awe of Iceland’s mid-Atlantic ridge system volcanics and its glacial geology, I still like to see sediments and fossils. So – as I was doing my pre-trip research into Icelandic geology, I found that there are about 500 meters of Pliocene strata exposed on the west coast of the Tjornes Peninsula in northern Iceland. Needless to say, the Tjornes Peninsula became part of my travels in Iceland.

The best way to access the Tjornes sequence is to go to the Tungulending Guesthouse, which is about 12 km north of Husavik. The turnoff for the guesthouse is just off Highway 85 and signed as shown by the photo below. Of course we missed it and kept driving a few km up the main road before we stopped to ask a local farmer. The farmer knew exactly where we wanted to go and sent us back down the road to Tungulending. Once we saw the Tungulending main sign and then passed the guesthouse gate, we knew we were headed in the right direction.

The Tjornes Pliocene strata contain both marine and continental deposits. The strata sit on the Kaldakvisl lavas while the Hoskuldsvik lavas cap the sedimentary sequence. The Tjornes Formation records a coastal environment that includes estuary-swamp, shallow marine-beach, and swamp-fluvial settings that existed in between the basaltic lava events (Simonarsson and Eriksson, 2008). These strata include a diverse mollusc fauna and recently the oldest marine vertebrate fossil in Iceland, a partial skull from a fossil whale (a large right whale), was also found within the Tjornes Formation (Field and others, 2017). Jonathon Hall, a Doctoral Researcher in the School of Geography, Earth and Environmental Sciences, University of Birmingham – UK, has put together a great leaflet on the geology of the Tjornes Peninsula, and the leaflet content can be found here: Geology of the Tjornes Peninsula.

The road leading down to the Tungulending Guesthouse cuts through the Tjornes sedimentary sequence. Note the car on the road near the guesthouse for scale.
The Tjornes Formation is well exposed in a drainage by the Tungulending Guesthouse.
Mollusc fossil fauna of the Tjornes Formation.
Shelly beds within the Tjornes Formation.
Cross-bedded strata with lenses of shelly beds within the Tjornes Formation.

Even if you are enthralled with Iceland’s volcanic and glacial geology, it is still well worth a look at the Tjornes Formation and a visit to the Tungulending Guesthouse for good conversation and food!

The Tungulending Guesthouse with the Pliocene Tjornes Formation in the background.