Reykjavík - Nesjavellir - Þingvellir
This trip starts and ends in Reykjavík; expected duration is 8 hours. Since you are all science teachers, I hope to be able to cover the basics while showing you some of the wonders of mother nature on our way. We will stop in several places, with four highlights, and as promised, one is a good hike.
On the way to the first stop
As we drive from Reykjavík, through an old interglacial shield, Mosfellsheiði, we will have an excellent view ahead of us to the móberg (older subglacial hyaloclastite) ridges of Dyrafjöll and the active volcano Hengill. This is the main volcano in the area, which last erupted about 2000 years ago, and is a part of the West Volcano Zone in Iceland. Along the road, notice a huge pipe. This holds the geothermal hot water for the capital area. The hot water comes from the Nesjavellir power plant, which we will see from our first stop.
The Hengill geothermal area is one of the largest of its kind in Iceland, covering approximately 100km2. There are two power stations getting their energy from Hengill, Hellisheiði power plant and Nesjavellir power plant. Nesjavellir plant utilizes geothermal water and steam with production capacity of 120 MW of electricity and 300 MW of thermal energy, which is 1800 liters per second. Hellisheiði Power plant production capacity is 303 MW of electricity and 133 MW of thermal energy, which can be increased significantly.
How Iceland formed & the tectonic plates
To understand how our country was formed, and the dynamic forces that have and still are shaping it today, we need to know that Iceland sits right on the volcanic hotspot. When the US Navy was able to map the Atlantic ocean floor they found the Mid-Atlantic Ridge, and discovered it’s volcanic activity. They also realized it was separated by a huge tear, which is the boundary between the North American and Eurasian plates.
In Iceland one can clearly see on land the appearance and structure of the plate boundary between the North American and Eurasian Plates, which cross here where the Mid-Atlantic Ocean Ridge is visible above sea level.
The country sits on a hotspot, and the magmatism produces a thick crust which leads to a complicated and wider plate boundary deformation zone than can be seen along a normal oceanic plate boundary. Rift jumps and unstable boundaries are results of relative movement of the boundary with respect to the roots of the hotspot. Distinct tectonic characteristics are seen when crustal blocks or microplates are transferred between the main plates, and the plate boundary zone divides into segments that are physiographically relatively distinct, yet similar. The segments are mostly oblique to the relative spreading direction of the two plates.
Convection currents of hot rock pull the Ridge apart. Magma surges up to fill the cracks, then cools, and finally hardens as it comes close to the surface, forming new land. Like a conveyor belt it continually pushes Iceland apart. It moves on average about 2 cm per year.
The hotspot beneath Iceland is the reason the Ridge rose out of the ocean and the country was formed. The hotspot and Ridge bumped into each other millions of years ago, and when the Ridge had drifted towards the east, it hit the fixed Icelandic hotspot. Combined, they spewed up what is now our country.
Hope you enjoy the trip!