Up for some adventure?
Our first stop is going to be the small town of Grindavík, where we start the first adventure of the day: Driving ATVs to the local geological sights.
Grindavík is only about a 45-minute drive from Reykjavík. We will look at some geological facts on the way.
From the Hengill volcanic system in the east, at 803 meters above sea level, dropping westwards to the Reykjanes system at 243 meters, you’ll see the decreasing influence of the mantle plume. What you see in the distance on your left, is the móberg mountain range of the peninsula, and from there at about 200-240 meters above sea level, two of the three Holocene lava shields, Hrútagjá and Þráinskjöldur. These two produced pahoehoe lavas spreading northwards and forming the 20 km coastline you see to your right. As we turn towards Grindavík, we can see to the right, the third lava shield, Sandfellshæð, which has a more regular shape and covers a large part of the peninsula’s southwest corner. All three shields are the principal agents responsible for the area raising out of the sea about 14,000 years ago.
Once we reach Grindavík, we will explore the surroundings in the Reykjanes area by driving on ATVs on marked trails.
The tour is tailor-made for our trip, and takes two hours. We will be riding through all kinds of terrain, aiming first towards Þorbjarnarfell, a free-standing and the highest móberg volcano in Reykjanes (243 meters). The dormant volcano is split by fault lines, which shape a shallow valley. Onward we continue west to the 10 km row of multiple scoria and spatter cones of Eldvörp.
Eldvörp was formed in the Reykjanes Fires 1210-1240, and are a part of the Svartsengi geothermal system. The lava from the crater row covers about 20 km of the Reykjanes peninsula, and is one of the most Holocene lava flows in the area.
As we ride alongside the Eldvörp craters, our next stop is the local hot spring area, generally called Gunnuhver, where you will see a group of vigorous mud pools and steam vents. These are formed where steam generated by boiling water in the geothermal reservoir condenses and mixes with surface water. Gases such as carbon dioxide and hydrogen sulphide acidify the water, which causes the fresh lava rock to turn to clay. The largest and tallest mud pool among the hot springs is Gunnuhver, with a rim of mud and boiling vigorously. Due to frequent earthquakes in the restless Reykjanes area, changes have occurred which revived the steam field intermittently, and allowed the deep reservoir water to escape to the surface through geysers, while others are extinct. The deep water is by origin sea water, rich in dissolved chlorides and silica, which have spattered and are visible on Kísilhóll (Silica hill).
The ride continues towards the ocean, where you will see the rock formations of Valahnúkur, the shoreline at Reykjanes, where the Mid-Atlantic Ridge rises out of the sea forming the rift valley with a series of 40-100 meters high steep móberg hills, composed of pillow lava, which is the most common lava types on earth since it comes from the oceanic crust. It is rare to find on land, like all over Iceland, hydroclastic tephra (a mixture of lava rocks and hardened volcanic ash, here called móberg) which forms when 1200°C hot lava rapidly cools in water and forms glass fragments which quickly transform into móberg, and breccia; which forms when ash or slag form angled slopes. Individual parts roll down the slope, covered with ash and form the breccia layer. Lava shields border the móberg hills on both sides, and the waves breaking on the troll-stone looking rocks give us an idea of the force of wind and water on the rock. From here we have a good view of Eldey and the oldest lighthouse in Iceland.
Next you will be riding through a black lava field (Game of Thrones filming location), towards the black sandy beach Sandvík, where the award-winning Clint Eastwood movie Flags of our Fathers was filmed. A short distance from Sandvík you find yourselves in a rocky canyon, which is actually where you can see the tectonic plates rift apart.
After a short stop, our bus will pick us up and we will head back to Grindavík for a warm lobster or vegetable soup, where you can also use facilities. The bus ride will take about 20 minutes and we will stop in Grindavík for 30 minutes. Everyone please be back in the bus and ready to depart at 12:00.