* Earth's Early Formation: The Earth formed from a giant cloud of dust and gas called a nebula. As this material coalesced, gravitational energy caused the planet to heat up immensely. This intense heat melted the entire Earth, creating a massive ocean of magma.
* Magma Solidification: Over time, as the Earth began to cool, the outer layers of this molten rock (magma) solidified. This process of cooling and solidifying magma is how igneous rocks are formed.
* No Pre-Existing Rocks: Since there were no pre-existing rocks at this early stage, there was no way for sedimentary or metamorphic rocks to form.
* Evidence from Meteorites: We can study meteorites, which are remnants of the early solar system, to understand the composition of Earth's early materials. These meteorites are primarily composed of igneous rocks, supporting the idea that Earth's early rocks were also igneous.
In summary: The extreme heat of Earth's early formation led to the creation of a molten planet. As the surface cooled, this molten rock solidified into igneous rocks, making them the first type of rock on Earth.
