Volcanism

The surface of Mercury has been shaped by three processes: impact cratering where large objects struck the surface resulting in crater formation, volcanism where lava flooded the surface, and tectonic activity where the planet's crust moved in order to adjust to the planetary cooling and contracting.

The findings made during MESSENGER’s mission included discovering that Mercury was abundant in volatile elements (potassium, sodium, and sulfur), that there’s water ice at its poles and that volcanism played an important role in shaping the planet’s surface.

The Eratosthenian Period (3.2–1.1 aeons ago) and the Copernican Period (1.1 aeons ago to present) were times of lesser volcanism and a still lower, probably constant impact rate.

This rejuvenation-stage or post-erosional volcanism produces lava even more alkalic than late-stage volcanism.

Some 200 million years ago, the rocks that became the Palisades cliffs just across the Hudson River from Manhattan formed during volcanic activity that helped rip apart the ancient supercontinent Pangea. That volcanism helped lead to the birth of the Atlantic Ocean while it also contributed to killing off as much as a quarter of all life on Earth during the event known as the end-Triassic mass extinction.