Frozen Fossil

Frozen Fossil is a buried ruin that appears in frozen areas of the map, typically inside a circular geode with one large and one small Fossil Fragment. It is part of the fossil ruin set and is found alongside other major fossil sites such as Amber Fossil, Petrified Fossil, and Ancient Specimen. In the generated chamber, the fossil rests on two Fossil tiles, with two Wolframite tiles at the top and the remaining space filled with Ice, Snow, and Oxygen at the surrounding biome temperature.

Frozen Fossil can appear in several frozen biome variants. In the base version it is generated in a cold environment, while the CO2 Lakes variant is much colder and includes a liquid carbon dioxide lake feature. The Solid variant contains no terrain features and is used in the Frozen Core World Trait; in this version, Oxygen is frozen into Liquid Oxygen and Carbon Dioxide into Solid Carbon Dioxide. Frozen biomes do not contain Critters.

A few practical notes make excavation safer and more useful:

• Duplicants can work in low temperatures without issue, so the ruin can usually be mined out directly.
• If you want to preserve the frozen area as a cooling source for later, leave the Abyssalite intact and insulate the entrance instead of opening the chamber fully.
• Melting Ice and Snow tiles directly yields twice as much water as mining them first and then melting the debris.
• Venting heat into a frozen biome is generally avoided only when it would disrupt wild Sleet Wheat.
• The CO2 Lakes variant may naturally contain liquid carbon dioxide because of the low temperature.

Frozen Fossil is one of the map features associated with buried points of interest, so uncovering one fossil ruin can help reveal the positions of the others.