No geological process is truly "unchanging" when it comes to rocks. Over vast geological timescales, even the deepest rocks are affected by:

* Heat and Pressure: The Earth's interior is incredibly hot and under immense pressure. This can cause rocks to change their mineral composition and structure through metamorphism.

* Plate Tectonics: The movement of tectonic plates can bring rocks deep underground, subject them to heat and pressure, and then bring them back to the surface through uplift and erosion.

* Radioactive Decay: Radioactive elements within rocks decay over time, generating heat and altering the rock's composition.

However, there are processes that are less likely to significantly change rocks deep within the Earth:

* Weathering: Weathering, the breakdown of rocks by wind, rain, and ice, is primarily a surface process.

* Erosion: While erosion can move rocks, it's less likely to significantly alter the deep rock itself.

The most accurate answer is:

There is no geological process that can *completely* prevent change in a rock buried deep inside the Earth. Even deep within the Earth, rocks are constantly being transformed by the Earth's dynamic processes.