The greatest volume of magma produced on earth occurs at hint: it's where the vast majority of new crust forms on earth.

Divergent boundaries such as the mid-oceanic ridge system.

Explanation:

Divergent boundaries occur when plate boundaries pull away from each other. Molten rock or magma rise from the gap between the two plates, rising up to the sea floor where it cools down to form new crust. It is the mid-ocean ridges where you see the most magma produced and there has not been any other tectonic event or area that could match its procution since the Precambrian period.