The Geology of Lofoten-Vesterålen

The geology of Lofoten-Vesterålen offers a unique opportunity to visit rocks and landscapes that record 2.7 billion years of Earth history. Most of the rocks that comprise the area were originally formed in the Archean and Paleoproterozoic eras (between 2.7-1.6 billion years ago). The oldest rocks, found mostly in Vesterålen, formed in the Archean (before 2.5 billion years ago), at a time when Earth’s atmosphere started to become enriched in oxygen. This forms rocks such as iron formations, and the bacteria involved in oxygen generation sunk to the ocean floor forming organic material that became incorporated into sedimentary rocks. The organic material later became graphite, which was mined in the area up until 100 years ago. Between 1.95 and 1.5 billion years ago, during multiple continent-continent collision events, the majority of the Lofoten rocks (mostly intrusive rocks) were formed and deformed and are known today as the Transscandinavian Igneous belt. This belt can be followed 1300 km southeastwards into southern Sweden, but Lofoten offers the most spectacular examples of the rocks due to its fjord landscape. Examples of the rocks include granites, charnockites, monzonites and gabbros. By 900 million years ago, Norway had become a part of the supercontinent known as Rodinia, although the rocks of Lofoten-Vesterålen are thought to be little affected by continental collision that led to its assembly. Afterward Rodinia split up into several smaller continents, and Norway, which then formed part of the continent Baltica, spent some time in the southern hemisphere.

At around 440 million years ago Baltica was near the equator. By 400 million years ago it had collided with Laurentia (today’s Greenland and North America) to form the supercontinent Pangaea. This is a significant event in Norway and formed the Caledonian mountain belt, a belt of rocks that sits on top of the older Lofoten rocks, and which can be equated to the modern Himalayan mountains. There are not many Caledonian rocks present in Lofoten today as they have been eroded away, but some garnet schists remain in the area of Leknes. During the continent-continent collision the Lofoten-Vesterålen rocks were thrust deep underneath the edge of Greenland (as India is thrust under Asia in the Himalaya today) so that they experienced very high pressure, forming eclogite (garnet and pyroxene “Christmas tree” rock). Due to the movement of the continental plates during this collision, earthquakes were also generated, and fossil earthquakes (known as pseudotachylytes) can be found in several areas around Lofoten. Thereafter the Caledonian mountain belt collapsed and was eroded down, and eventually around 160 million years ago a rift structure between Greenland and Norway formed, which would eventually become the Atlantic Ocean. The rocks deposited in the rift zone over the succeeding 20-30 million years came to form Norway’s rich oil reserves that are now found along the continental shelf (some just offshore Lofoten). The faults that accommodated this rifting caused the uplift of the entire Lofoten ridge and dictated the shape of some of its mountains. The faults are also the reason that we see the Lofoten ridge above sea level today.

By 66 million years ago the Norway had rifted from Greenland and North America and, the mid Atlantic Ridge, currently under Iceland, had formed; the Atlantic Ocean was slowly opening. Norway’s entire coast became relatively geologically quiet, the climate was warm, and modern life flourished. From 2.7 million years ago the climate had cooled and the subsequent period, up until today, has been characterized by several ice ages, shaping the glacial landscape we see in modern Lofoten-Vesterålen.

Programme

Day 1 Monday August 29^th 2022 Route: Amsterdam (or wherever you come from)– Oslo – Evenes – Laukvik

Transfer from Evenes Airport (arrival ? hrs), to Laukvik (170 km).

Late evening soup & bread; night in Kristine Moen’s Huset.

Day 2 Tuesday August 30^th Route: around Laukvik-

Geology around Laukvik (beach, Laukvik harbour, beach at Grunnførfjorden, Oxbow lake at Storvatnet, Viking boathouse)

Start with general geological introduction (Carly) from the Precambrium to the Caledonian.

Walk to the seaside to one of the very large erratic boulders. Pick up different type of stones. Transfer by bus to the harbor area of Laukvik. Geological introduction of some stones at this collectors site of all kind of stones from the area (not in situ).

Drive along the marvellous coast: Quaternary geology and marine terraces at Delp. Stream with an oxbow lake – Storvatnet. Archeological site (the remains of three Viking boat houses). Walk along the beach (bubblegum corals – Paragorgia arborea (a recent cold water coral) and notice the difference between wind blown (eolian) and (peri) glacial beach sand.

Evening at Polar Light Centre in Laukvik – Lecture by Rob Stammes on all scientific aspects of this phenomena. In the trip of 2021 we had one night with marvelous Northern Light. The photograph is taken at Moen’s Huset on September 3d 2021 at 23.30 hours.

The 2021 trip.

Day 3 Wednesday August 31^st Route: Laukvik – Leknes – Nusfjord (Storvatnet lake) – Laukvik

One of the most interesting and nice outcrops we’ll find on this trip are eclogites. They consist of three minerals: green (omvasite), red garnets and white plagioclase. They originate in the collision zone of two continents on depths of 100 kilometers. We visit the sample site of the geologist Steltenpohl, who described these rocks in detail in 2011. Here the eclogites contain also the mineral kyanite. Kyanite is only formed under high P and T conditions.

Near Boe we can spot pseudotachylites in the exposed rocks, but also we can find there some glaciation striae on the rocksurface left there by the glaciers of the last Ice age.

On our way back we visit the charming old village Nusfjord – a UNESCO world heritage site.

Day 4 Thursday September 1^st Vesterålen (Proterozoic)

Trip to Vesterålen (= the most Western islands of Norway) drive via Gullesfjord-Sortland, back along Eidsfjord to look at pseudotachylytes (fossil earthquakes) and Eidsfjord fault, Melbu ferry back.

The whole trip from there over the island Sortland and Langoya takes 2h20 min to drive to the tiny village of Hovden with a little light house standing on the outermost Western shore of Norway. To the west you look straight to Iceland/Greenland. In the rocks under the lighthouse you can spot is a (geological) mappable border between monzonite and gabbro.

We’ll visit a variety of sites with exposures of Precambric rocks. The gabbro’s are sometimes layered. The lower part of it is dark and sometimes with magnetic veins in it and it’s possible to mine these rocks in the future for titanium. The upper gabbro layers are much lighter and contain more plagioclase, they are not only lighter in colour but also in weight. On the way back near Eidsfjorden we can spot the results of a ”fossil” earthquake in the valley side. This earthquake dates from the Caledonian orogenesis around 400 My ago. Back to Laukvik by the ferry Melbu – Fiskebol.

Day 5 Friday September 2^nd: Laukvik – Henningsvaer – Laukvik

Geology of Hennigsvaer (a marvellous exposure of basement rocks with dolerite dykes, the Hopen intrusion, dated at 1863 Ma. Visit to the old fishermans village of Henninsvaer.

Day 6 Saturday September 3^d Laukvik – Hanøy – Djupfjord- Laukvik

Archean rocks (graphite mine, Archean banded iron formation at Hanøy ferry stop, Archean orthopyroxene gneiss at Djupfjord)

Day 7 Sunday September 4^th Boattrip on the fjords

Boattrip from Svolvaer harbour into the straight Raftsundet fjord to Troll fjorden and back. Explanation of the faulting system, all the bigger fjords of the Lofoten are NE/SW oriented as the Raftsundet is too, the Trollefjord is a fault with a direction rectangular to that.

Day 8 Monday September 5^th  Laukvik- Amsterdam (SAS) or to the UK

OTHER INFORMATION

This trip is offered to you including the flight to the Lofoten. There is no direct flight from Amsterdam. We fly to Narvik (Evenes) or via Bodo to Svolvaer. The planes are getting smaller and smaller.

Please be reminded of travel and cancellation insurance and make sure your passport is valid.

Landscape at Laukvik

Also for geology of quarternary age there is a lot to see: marine terrace, dropstones, nunataks, u valleys, cirques. Explanations will be provided on the spot.