Kissenstrukturen

Kissenstrukturen, translated from German as "cushion structures," refers to a type of geological formation characterized by rounded, pillow-like masses of rock. These structures are most commonly observed in volcanic rocks, particularly those formed by the eruption of basaltic lava into water or wet sediment. The rapid cooling of the outer surface of the lava flow by the surrounding water creates a solidified crust, while the molten interior continues to flow, pushing against this crust to form a bulbous, cushion-like shape. As subsequent lava extrudes, it piles up against existing pillows, resulting in an accumulation of these distinctive forms.

The shape and size of Kissenstrukturen can vary depending on factors such as the viscosity of the lava, the rate of extrusion, and the amount of water present. They often exhibit concentric layering or banding within the individual pillows, reflecting the cooling and solidification process. In cross-section, the pillows typically appear rounded on the top and flattened or irregular on the bottom where they have rested on previously formed structures. Kissenstrukturen are significant indicators of subaqueous volcanic activity, providing valuable clues about the ancient depositional environments of sedimentary and volcanic successions. They are found in various geological settings worldwide where underwater volcanic eruptions have occurred.