On the trail of two of the Vulkaneifel’s geological phenomena

Eifel volcanoes:
They were first active around 45 to 35 million years ago. There was then a second phase around a million years ago that ended with the most recent eruption, the Ulmener Maar, around 10,000 years ago. Around 350 eruptions have been recorded in the Vulkaneifel, of which around 270 were during the most recent phase.

Essentially there are two types of volcanoes in the region:
cones and maar craters.

Volcanic cones

When magma rises up from the earth’s core, depending on its composition, extremely high pressure can build up; this is then released in a large explosion. It throws out lava, ash and slag and as the pressure drops there are also lava flows.
The geological interaction of these deposits gradually leads to the cinder cones and stratovolcanoes that you can see in the Eifel.

Maar craters

If, when the magma rises, it meets aquifers, then this water evaporates suddenly, leading to massive explosions. The surrounding rock at the contact point is shattered, pushed upwards and ejected. The chamber created by the explosion then collapses and a crater remains on the earth’s surface, surrounded by a circular wall made of the ejected material – this is a maar. The collapsed crater sometimes fills with water and becomes a maar lake.
Maars are what characterises the Vulkaneifel. 75 of them have been verified and ten contain a lake - “the eyes of the Eifel”. In many other maar craters, after the land dried up, the lakes became moors with special plant communities. Other maars never contained a lake or levelled off through natural erosion and are now simply flat, bowl-shaped hollows.

Flyer - "The Maars of the Vulkan Eifel and how they were formed"

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