THE EXTINCT VOLCANO AT HEGHEȘ HILL

This volcano is one of the witnesses of the volcanic activity within the Perșani Mountains Volcanic Field. It is approximately 1.2 million years old and was formed as a result of Strombolian-type eruptions.

During these explosive eruptions, incandescent lava fragments and semi-solid blocks were ejected from the volcanic vent and fell around the crater, forming a volcanic cone. The larger volcanic bombs (>64 mm) fell closer to the vent, while smaller lapilli fragments (2–64 mm) and volcanic ash (<2 mm) remained longer in the eruption column and eventually settled on the outer slopes of the volcano.

Such volcanic explosions can last from a few weeks to several years. After the volcanic activity ceased, vegetationbegan to grow, covering the cone. Due to the extraction of scoria (slag), a depression was formed in the ground, offering a unique view into the interior of the scoria cone.

If you lift one of the stones, you will notice how light it is — it is a porous rock, similar in texture to a sponge. These are called volcanic scoria, containing numerous vesicles, the traces of former gas bubbles in the erupted magma. In fact, these trapped gases were responsible for triggering the repeated short explosive events.

As the erupted material solidified rapidly, the remains of the gas bubbles were preserved in the scoria, while the volcanic gases escaped. The reddish color of the rock is due to the thermal oxidation of its iron-rich (Fe) content.
Yes — it is, quite literally, a “rusted rock.”