The depositional pattern of CaCO₃ and other materials that extend upwards from the floor of a limestone cavern is known as:

The correct option is Stalagmite.

Explanation:

In karst topography, limestone caverns are formed through the dissolution of calcium carbonate (CaCO₃) by acidic groundwater. When water containing dissolved calcium bicarbonate drips inside a cave, carbon dioxide escapes into the air. This chemical process causes calcium carbonate to precipitate out of the water droplets and deposit as solid mineral formations.

These mineral deposits form distinct structures depending on where they grow:

1. Stalagmites: These are mineral deposits that build up and extend upwards from the floor of a cavern due to water dripping down from above.

2. Stalactites: These are icicle-shaped formations that hang downwards from the ceiling of a cavern.

3. Dripstone: A general term for cave formations produced by precipitation of minerals from dripping water.

4. Helictites: A type of speleothem that grows in curved or branching shapes that seem to defy gravity.

Therefore, the specific depositional pattern of CaCO₃ extending upwards from the cave floor is defined as a stalagmite.