It may or may not turn acidic depending on the area or time of the year it is.
Gravity increases as mass increases.
Gravity decreases when distance decreases
One example is the country of Iceland which is a large island right on the mid-Atlantic ridge which is where the Atlantic oceanic plate is rifted in two and where the underlying magma wells up to the surface as the two sides to the plate move opposite to each other. The resulting volcanic rock then builds itself up into an island.
