Which type of rock formation is commonly associated with past volcanic activity?

Igneous intrusions are directly linked to past volcanic activity because they form from the cooling and solidification of molten rock, known as magma, that originates from deep within the Earth. When this magma rises towards the surface, it can either erupt as lava during a volcanic eruption or cool and crystallize beneath the surface, leading to the formation of various igneous rocks, such as granite or diorite. The characteristics of igneous intrusions, including their mineral composition and crystalline structure, are clear indicators of volcanic processes.

Metamorphic rocks are transformed from existing rocks under heat and pressure but do not indicate past volcanic activity specifically. They may have originated as either igneous, sedimentary, or other metamorphic rocks, hence lacking a direct association with volcanic history.

Sedimentary rocks are formed from the accumulation and compaction of mineral and organic particles, typically in water environments, and are not indicative of volcanic activity. These rocks may contain fossils and are layered due to the deposition process, making them more representative of environments after volcanic events rather than during.

Chunks of unaltered soil are not categorized as rock formations and do not signify any volcanic activity. Soil may contain organic material and sediments, but it does not form from the solid