GEOSITE FIR TREES AND EMERALD LAKE

This volcanic structure, approximately 1.2 million years old, began its activity with repeated magmatic and phreatomagmatic explosions (the interaction between magma and groundwater), depositing multiple layers composed of volcanic sediments (pyroclastics).

Thus, in the first phase, a maar-type volcanic cone or tuff ring was formed, made up of parallel strata of pyroclastic material. Over time, as the groundwater was depleted and the amount of volcanic gases decreased, lava intrusion began within the volcanic vent and crater, forming a lava lake. Following the cooling and solidification of this lava lake, basaltic rocks were created.

Volcanic activity ended with a Strombolian-type eruption, which formed the scoria cone of Hegheș Hill.

At the site of today’s “Emerald Lake”, there was an active basalt quarry in the early 2000s, where basalt was extracted. Basalt is mainly used in construction (roads, railways), but also for decorative purposes, sculptures, and other artistic works. When basalt is heated and extruded, it produces basalt wool, an excellent thermal insulating material.

As the quarry deepened, a small spring was reached, which, together with rainwater and meltwater, gradually filled the pit and formed a lake whose water level rises by several centimeters each year.

Today, the lake is approximately 15–20 meters deep. Its emerald color is caused by green algae and tiny rock particlessuspended in the water, which reflect sunlight. The lake’s color varies throughout the day, depending on the angle of sunlight, and also changes with the seasons. The most intense hue appears in spring and summer, when the algae bloom and sunny days are more frequent.