Final answer:
The step that is not a part of the rock cycle is 'Sediments melt deep beneath Earth’s surface,' because sediments compact and cement into rock rather than melt. The rock cycle involves the transformation of rocks into different types due to cooling, heat, pressure, and erosion, but not sediment melting.
Step-by-step explanation:
The step that is not a part of the rock cycle is 'Sediments melt deep beneath Earth’s surface.' This is not a step in the cycle because sediment, by definition, does not melt but rather lithifies, or compacts and cements, into sedimentary rock. The rock cycle encompasses the formation and transformation of rocks due to processes such as cooling, breaking down, and being subjected to heat and pressure, but the melting of sediments is not characteristic of these cycles.
Igneous rocks form when magma or lava cools and solidifies. Metamorphic rocks are created when existing rocks are altered by extreme heat and pressure, characteristically deep beneath the Earth's surface or at tectonic plate boundaries. Sedimentary rocks are formed through the cementation of sediment and organic material, not through melting.
It's important to understand that rocks on Earth are part of a dynamic system driven by plate tectonics, and this constant movement is responsible for the conditions that lead to the rock cycle. Changes in temperature and pressure, alongside geological activity, contribute to the continuous transition among igneous, sedimentary, and metamorphic rock forms.