suppressorium

The suppressorium is a rare and fascinating geological feature found in certain volcanic environments, characterized by a distinctive columnar structure formed during the cooling and solidification of lava. This term is derived from the Latin *suppressus*, meaning "pressed down," which reflects the appearance of the feature as a flattened or compressed column within a larger lava flow or intrusion.

Suppressoria typically develop in basaltic lava flows, where rapid cooling causes contraction and the formation of polygonal fractures. Unlike more common columnar jointing, which produces vertical, prismatic columns, suppressoria exhibit a flattened, often mushroom-like shape at their upper surfaces. These structures are thought to form due to differential cooling rates, where the upper layers cool and contract more quickly than the underlying lava, creating a downward pressure that deforms the columns.

Suppressoria are most commonly observed in shield volcanoes and flood basalt provinces, such as those found in Iceland, the Deccan Traps of India, and the Columbia River Basalt Group in the United States. Their presence can provide insights into the dynamics of lava flow and cooling processes, as well as the mechanical properties of volcanic rock.

While suppressoria are not as widely recognized as other volcanic formations, they contribute to the study of igneous petrology and volcanic geomorphology. Their study helps geologists understand the physical behavior of lava during solidification and the factors influencing the formation of columnar structures in volcanic environments.