Why do ingneous rocks stick up above the ground?

1. Intrusive Activity: When magma from the Earth's mantle rises and solidifies beneath the surface, it can form large masses of igneous rocks called plutons. These plutons can be pushed upwards by tectonic forces, resulting in the formation of mountains or domes that protrude above the surrounding terrain.

2. Volcanic Activity: Volcanic eruptions bring magma to the surface, where it cools and solidifies to form extrusive igneous rocks. Volcanic mountains and domes are formed as layers of lava and pyroclastic materials accumulate around the eruption site. Over time, these features can rise to significant elevations above the surrounding landscape.

3. Differential Erosion: Igneous rocks are often more resistant to erosion compared to sedimentary and metamorphic rocks. In regions subjected to weathering and erosion, softer rocks are eroded away at a faster rate, leaving the more durable igneous rocks standing out as prominent features in the landscape.

4. Uplift and Exhumation: Tectonic processes such as orogeny (mountain-building) and crustal uplift can raise igneous rocks to higher elevations. Over geological time, erosion and denudation remove the overlying rocks, exposing the underlying igneous intrusions or volcanic edifices.

5. Glacial Processes: In areas affected by glaciers or ice sheets, the erosion of softer rocks by ice can carve out valleys and depressions, leaving behind more resistant igneous rocks as elevated peaks or ridges.

6. Faults and Fractures: Faults and fractures in the Earth's crust can displace igneous rocks, causing them to rise relative to the surrounding terrain. This process can create fault-block mountains or horsts, where igneous rocks are uplifted along fault lines.

7. Density Differences: Igneous rocks are generally denser than sedimentary rocks. In some cases, the buoyancy forces exerted by less dense materials, such as sedimentary basins, can cause the denser igneous rocks to rise and form topographic highs.

It's important to note that the specific mechanisms responsible for igneous rocks sticking up above the ground can vary depending on the geological context and region. Multiple processes may have acted in combination to shape the landscape and produce the observed elevation differences.