The last day of the GEOL 390 field trip to Iceland was to be a long day’s drive back from Akureyri in the north to Reykjavik in the south, a total of 385 km.  This was to be through some of the ‘less geologically exciting’ parts of Iceland, but as usual we had some surprises.

The day started well with sun at last and a cool 6-7 C.  The bus was loaded and ready for a later departure than usual at 10 am.  Fours stops were planned along the route based on our reconnaissance of the road during Day 8.

The first stop was to examine some jagged mountain peaks from the road, that were distinctly different from the table top plateaus of the Tertiary basalts – likely scrapped flat during a number of previous glacial.   These jagged peaks corresponded to some rhyolite extrusives on the geology map.  However, with the fog low on the mountains and the driver focused on the road the site was completely missed!  Something for next time.

The second stop was to examine a sedimentary lignite layer (a precursor to coal) that is clearly shown on the Iceland geology maps as black lines within the Tertiary basalts.  This layers marks a geological unconformity and a period of  a warmer climate and vegetation growth.  The most likely looking site was a steeper river canyon where we had spotted some red layering previously.  We found a good road pullout for a 10 minute stop, which as usual turned into 45 minutes!  While the students went off to check out some of the red layering, Tim chatted with some tourists (a drone operator and his wife) to see if they would photograph the layers for us on the other side of the canyon.  They did so and promised to send photos later.  From some samples that were collected it was deduced that the red laying was a red sandstone marking a distinct period of sediment deposition between volcanic events.  No sign of lignite.  (A later discussion with a local geologist indicated that this layer was typically very difficult to locate, as it easily erodes away.)

 

The drive continued south thought some amazing upland valleys, past the ends of fiords and along the edges of large braided rivers.  We eventually arrived at the third stop a series of two almost perfect scoria cones with recent basalt lava flows emanating from their craters, both that had been breached.  This was a national monument with a well-developed trail system and some excellent explanation boards. ( A distinct contrast to the previous days in Lake Myvatn area, where tourist infrastructure was definitely missing in the mud pools.)  The sun was out, the breeze was blowing and the sights amazing – Iceland at its best.

After a quick stop in Borgannes, it was on to the last leg of the journey through the 6 km and 1000 krone ($14) toll tunnel to the last stop – a series of sub vertical dikes in a sequence of Pleistocene lavas.  A quick race to the dykes up a steep slope by two volunteers confirmed the composition of dikes as mafic and the surrounding basalts flows with column structures.

A short drive, before arriving in Reykjavik and the search for the City Hostel located near the Iceland International soccer field, a large camping site and of course the geothermally heated swimming pool.  Dinner at the local fish restaurant include: burgers, one whale steak, haddock and shrimp.  A night out for some to see the late (or early) 1-5 am nightlife of downtown Reykjavik and a dip in the swimming pool for others.

The trip is at an end with some flying out the next day, others staying one more night and one staying in  Iceland 10 more days to see more.  What a great way to spend 10 days in the field with  some of the most active geology in the world.  Looking forward to the next visit to Iceland already!

We started our 9^th day with a short drive out east to the Myvatn Lake area. This region is packed with lots of geological goodies. We could have spent another day but had to cherry pick our stops. We took advantage of a lookout info map coming into the valley in order to get our bearings.

Our second stop of the day was where historic lava flows meet the Myvatn Lake. Here we found a collapsed lava tube and got to peek into the flow. The Krafla rift system is at least 300,000 years old, with many layers of lava flows and explosion craters. There are two historic flows in the area, the older being the Myvatn flow, dated 1724 to 1729. The Krafla Fires, the most recent eruption, occurred from 1975 to 1984. During these eruptions, magma was forced along fissures in the ground and erupted out along the surface as lava. Nine times during the Krafla Fires lava erupted onto the surface. More frequently the molten rock stayed within the fissures below ground. Throughout this time, magma filled the magma chamber below the surface and later erupted, causing the ground level to rise and fall respectively. It is estimated that 250,000,000 m3 of lava was erupted during the Krafla Fires (approximately 100,000 Olympic sized swimming pools). (from the Krafla Power Plant interpretive signage, 06/04/2017).

Our next stop was Leirhnjukur (clay hill), where geothermal fluid has altered the basalt to clay and other geothermal minerals. There was supposed to be some rhyolite around here but we didn’t get to see it. Despite the hotspring water being boiling hot, the day was very cold. Aaron even put a coat on! Highway reports put it at 4 degrees C before wind chill.

Very generally speaking, the geothermal fluids break down the basalt rock in the lava fields to create new colourful geothermal minerals; such as grey clays, yellow Sulphur, rusty red iron oxide, and white silicate minerals. Below shows where the geothermal area meets the Krafla lava flow.

With the weather and timing, we decided to cut our trip to the Viti Maar short and just snap a selfie. At least we got out of the car. Another tourist there just sent his drone to view the explosive crater that formed in the 1724 eruption.

Our next stop was to the Krafla Geothermal Power Station to warm up. This turned out to be quite an informative stop and we learned much about the technical aspect of generating electricity from geothermal water. The Krafla Geothermal Power Station is Iceland’s first and still the largest power station in the country. It currently produces about 500 GWh annually Construction of this power station began in 1974, but delays due to the Krafla Fires put back the official launch until 1977. (https://en.wikipedia.org/wiki/Krafla_Power_Station, accessed 06/06/2017). According to the interpretive signage at the power plant, 99% of the electricity produced in Iceland is renewable, being mostly either geothermal power or hydropower. They continue to innovate, with future ideas involving deeper wells and hotter water. Below is a shot of the different drill bits used to drill a geothermal well, as well as their method of dealing with a road-pipeline intersection.

Next stop was the mud pots near Namafjall Mountain. Námafjall is a very hot (80-100°C!) geothermal area just south of the Krafla geothermal power plant. Tourists flock to this little roadside stop to see its fumaroles and mud pots. It was quite beautiful with all the hydrothermal minerals. The tour busses were providing their patrons with little booties which would have been handy in keeping all the mud and clay off of our boots. We just went ‘low tech’ and used a handy puddle.

Besides basalts being broken down into fun new minerals, there were many fumeroles venting into the air. Along with steam, the fumaroles release hydrogen sulfide gas, which gives the area a particularly pungent smell if the wind has died down. In the past, Sulphur was mined from areas such as Námafjall to be used in the production of gunpowder.

Next stop was a rift called Grjotagja Cave. This one has a hotspring inside that was popular for bathing in times gone by but the Krafla eruptions increased the temperature so a dip in it now would not be fun. We were there for the geology but the tourists also like to come here as it was part of a scene in the popular Game of Thrones TV series.

Time being short, we decided to give Hverfjall crater a miss and skip over to Dimmugorgir.

Dimmuborgir is a labyrinth of towers that formed within a lava lake as the lava moved over water. The heated water generated steam which escaped up and formed towers. The towers were left behind as the lava lake was breached and remaining lava flowed out into channels.

There is a local legend about 13 troll brothers who live in Dimmuborgir and come out during the Yule season; sort of like a baker’s dozen of Santa Clauses. These characters have funny names like ‘Spoon Licker,’ ‘Sausage Swiper,’ and ‘Door Slammer.’ When they come out of their caves in winter to get ready for Christmas, you might spot them along the trails. (Taken from local interpretive signage and http://www.visitmyvatn.is/en/about-m-vatnssveit/winter, 06/06/2017)

At this point we were running late so had to do a quick lap through the labyrinth (with only a couple wrong turns) and head ‘home’ to Akureyri.

 

 

Snaefellsnes Peninsula is the area where Icelanders have their vacations, and the area is a geological smorgasbord.  Unlike the rest of Iceland’s black sand basalt beaches, here the sands are often white and golden, indicative of their felsic (andesite and rhyolite) origins. However we decided to cut short our Snaefellsnes leg because we had a long 5-hour journey north. There is only so much driving Tim should be doing every day, and arriving at base camp at midnight doesn’t leave enough time to eat and dry out the clothes and gear. Darkness however is never an issue, because there is 24-hour light, so it is easy to lose track of time. The previous night we decided to limit Snaefellsnes to only Myrar in the morning, which is on the southeast approach to the peninsula.   Fortunately, there sits Eldborg crater, the finest example of a spatter cone in Iceland.

Before the morning hike starts, our sheepfarmer host treats us to a sheep dog instructional session for a young pup. Highly entertaining. This young dog was every bit as energetic and determined as many in our young crew. Sheep are as omnipresent in Iceland as lava. There are also herds of domestic horses, but no cattle. Icelanders eat mutton, lamb, fish and horse.   All are on the menu. Beef is rare. Vegetables are imported, although the geothermal presence is making some greenhouses viable up here at the Arctic Circle.

The hike is about an hour through birch bushes growing on a lava field. Eldborg is 5000 years old, almost a perfect ellipsoid, 180m X 250 m, 50 m high, with a steep 40 – 60 degree slope.

 

The entire hike is across one of Iceland’s many lava fields. Actually, Iceland is one big lava field, which is only occasionally covered with enough sediments to create a soil, which if thick enough, creates the incredibly fertile agricultural base for which volcanoes are famous. Here the lava field varies between aa lava (blocky, chunky, jagged) further out, and pahoehoe lava (smooth, ropy, braided) closer in.  Both types made excellent stair material for our climb up.

 

That lead group is almost always Payton, Alex, Myles and Toby. This picture is three of those four, although the fourth has got to be in there somewhere.  Our spatter cone is the biggest in a sequence of five that aligns east-west, the same alignment as the en echelon fissure zones of the Snaefellsness peninsula.

Tim usually gets it right, but one thing geologists like to do as much as looking at rocks, is to argue about rocks, so opinions, opposition and alternative explanations are always welcome.  The rain is absolutely pouring here, and the wind is blowing hard.

 

The center crater of the spatter cone was a lava lake, and the bubbling and splashing would lap the edges, leaving a series of lava layers on the sides of the cone.  Myles commented that this process creates the same appearance as the very different exfoliation of granite.

 

This is a cinder cone adjacent to our spatter cone to the SSE.   The cinder cone also has a central vent (sometimes large enough to be a caldera). The cinder cone tephras (ash and rocks ejected by the volcanic vent in the centre) are here smaller, lighter, and more vesicular (riddled with holes) than the tephra at the top of our spatter cone.

 

 

Now we have returned to Borgarnes and are heading off on our big trip north. Here we have the Borgarfjordur anticline. Notice how the tree-lined ridge in the middle distance slopes steadily to the left (east).  This represents the eastern limb of the anticline.

Similar to Hawaii, Iceland is formed by a mantle hot-spot. However in Iceland’s case, the mantle hot-spot intersects the Mid-Atlantic Ridge, where the oceanic bottom spreads apart in a rift, an underwater volcanic chain, where ~ 90% of the world’s volcanoes exist. Iceland is composed of a series of rifts, some active, others inactive or extinct.   On Iceland, these rifts form large rift zones which jump eastward 100 – 200 km every few million years. The hot spot is relatively stationary, but the plates move, so the rift zones migrate east.  The hotspot center is currently under Vatnajokull, the great ice sheet in eastern Iceland.  The Borgarfjordur anticline is important because it is the high ground between two rift zones, which confirms the location of a rift jump.

 

Toby’s project is studying the timing of these rift jumps (by analyzing rock ages and locations of rifts zones). Here Toby is checking the location, dip (slope), and direction of a rift jump. Toby is showing perfect posture for this task – notice the straight spine and the deep crouch.

 

Callie commented on a previous blog that geologists love rocks and that is very true. Here Toby is indulging in his vocation, studying a rock. Toby is not actually wearing camouflage, but is rather undergoing the initial stages of lithification, whereby everything on the earth’s surface, including Toby, eventually turns back into rock. Of course, when we see this we always interrupt the process, but really we are only deferring the inevitable for some later time.

 

 

Day seven began with an early departure from the town and island of Heimaey, the largest and only inhabited island in the archipelago of Vestmannaeyjar, commonly referred to as the Westman Islands. The day began smoothly, despite one of the students boots having been mistakenly taken by Tim. The sunny weather permitted views of the islands that were not available during our trip to Heimaey two days prior, also allowing a much more comfortable ferry ride back to southern Iceland as many of us felt quite sea sick on the trip out.

 

 

The first stop of the day was at a relatively well preserved lava tube known as Raufarhólshellir. Despite being closed since December due to the nature of previous self-guided tours proving quite damaging to the area, Tim managed to convince some of the tour guide staff to allow us to enter for a quick view of this phenomenal volcanic feature. The volcanic textures and apparent series of flows provided us with insight into how these type of structures form, and what they can tell us about previous volcanic events. The lava tube originally formed approximately 5,200 years ago, and is comprised of somewhere between 10-15 layers of volcanic flows. It is believed that the eruption lasted around two years, resulting in the main section of this feature extending about 950 meters long. The staff informed us that the land owner has decided that the cave would now have restricted access to limit damage and littering in the lava tube.

 

 

 

 

The next site we visited was the Hellisheiði geothermal power station, owned and operated by Orka Náttúrunnar (ON Power), which roughly translates to Our Nature, a subsidiary of Orkuveita Reykjavíkur (OR), or Reykjavik Energy in English. The plant is located within the southern portion of the Hengill volcanic system. This power station is the largest geothermal power plant in Iceland, and the second largest geothermal power station in the world. The bedrock in this region is mainly comprised of basic to intermediate extrusive volcanic rocks of the pre-historic (prior to the settlement of Iceland) Holocene geological epoch. At this geothermal plant, hot water can be extracted from geothermal sources and pumped to the nearby communities for both heat and hot water usage. Approximately 99.9% of the homes within Reykjavik and the surrounding area are heated geothermally. Additionally, these geothermal fluids can be to produce electricity in a similar fashion to how steam engines produce energy. The processes responsible for producing these hot fluids within the subsurface are directly related to Iceland’s tectonic and geographic placement, directly overlying both the Mid-Atlantic Ridge, and a stationary mantle plume. A self-guided tour of the facility helped explain the various contributing factors to Iceland’s world renowned geothermal capabilities. A brief film explained that approximately one third of Iceland is underlain by active volcanic zones. The video explained how energy is extracted as steam and water, and is used to provide both hot water and electricity to nearby communities.

 

 

One of the problems with geothermal electricity production are the by-products hydrogen sulfide (H₂S) gas and carbon dioxide (CO₂) gas. Despite the misconception that there is very little that can be done with these gases in a sustainable timeframe, Iceland’s primary energy providers have proven that these gases can be reinjected into fractures in the underlying basalt, which results in the crystallization of certain minerals (H₂S -> Pyrite or Fools Gold & CO₂ -> Calcite) within the span of two years. This allows gases that are harmful to the environment to be converted back into rock. This form of energy production has proven both sustainable, as geothermal energy is a renewable resource, and efficient as approximately 27% of the country’s total electricity is sourced from geothermal activity. Overall, these factors demonstrate how Iceland is a global innovator in both the harnessing, and utilization of geothermal energy.

 

 

The final leg of our journey for the day was a visit to the northern section of the Hengill volcanic system which is host to the Nesjavellir geothermal power station. Also operated by Orka Náttúrunnar, the Nesjavellir geothermal plant is the second largest geothermal power station in Iceland. Although we were not provided the opportunity to tour this facility, the surrounding region was abundant with well-marked hiking trails that provided an up close view of various geothermal vents and the volcanic rocks that make up much of Iceland’s geothermal areas.

 

 

 

 

Despite common knowledge that the majority of Iceland’s bedrock consists of typical basalt, the basalt that appears in these areas does not fit this description. Many of the rocks have been significantly altered due to the presence of geothermal fluids, and are consequently quite variable in terms of mineralogy and texture. Along our hike, we observed two or more altered basalts that do not fit the characteristics of typical oceanic crust.

 

 

Just before returning to the bus, Tim made the observation that a regional map displayed the presence of a nearby river that was geothermally heated and could be used as a relaxing place to take a dip. Despite our excitement to see more geology and exciting rock formations, we quickly seized the opportunity and jumped right in.

 

 

This provided a momentary break from our research and the various stresses of field school, and reminded us of the once in a lifetime opportunity that this trip was providing. This also provided Alex with a once in a lifetime opportunity to take a selfie with Tim.

 

The drive to our hostel in Borgarnes was relaxing and provided all of us a well-needed opportunity to sleep, except for Tim who has been stuck with the responsibility of driving nearly the entire trip so far. What a day!

Heimaey Island is situated in the Vestmannaeyjar archipelago (Western islands) located in the southern region of Iceland.

Stop 1: Eldfell Volcano

After a long, arduous journey to the hostel we were warmed and rested, ready to tackle the day another day in Iceland. The day began with an early morning start with a hike up to the Eldfell volcano (220m in height) with less than optimal weather. As the hike continued on we gained altitude and we were exposed to stronger winds and the rain started to sting. Upon reaching the summit the visibility was lacking we ended the trek with a quick photo shoot. After a brief rest we returned to the hostel thoroughly soaked to eat some lunch.

 

Stop 2: Eldheimar (volcano museum)

Looking for a less wet activity we decided to attended the museum Eldheimar. At the museum we learned about the history of Vestmannaeyjar like the 1973 eruption of Eldfell and how the locals fought the oncoming lava flow to save the harbor and in the aftermath of the eruption the tephra that had fallen was then used to increase the surface area for the airport. There was also an exhibit on the formation of a new island Surtsey that came into existence in 1963 that has provided scientists a way to see how plants and fauna begin to inhabit new islands.

Stop 3: Outcrop near soccer field

Here we looked at some upper Pleistocene rocks with steeply dipping beds likely the remnants of an older volcano. My notebook decided it wanted to fly away in the heavy winds the island was experiencing.

Following this we went to the southernmost region of the island and we managed to spot an elusive puffin and experience the windiest part of the island.