Magmatic Landscape Construction

Magmatism is an important driver of landscape adjustment over ∼10% of Earth's land surface, producing 103‐ to 106‐km2 terrains that often persistently resurface with magma for 1–10 s of Myr. Construction of topography by magmatic intrusions and eruptions approaches or exceeds tectonic uplift rates in these settings, defining regimes of landscape evolution by the degree to which such magmatic construction outpaces erosion. We compile data that span the complete range of magmatism, from laccoliths, forced folds, and InSAR‐detected active intrusions, to explosive and effusive eruption deposits, cinder cones, stratovolcanoes, and calderas. Distributions of magmatic landforms represent topographic perturbations that span >10 orders of magnitude in planform areas and >6 orders of magnitude in relief, varying strongly with the style of magmatism. We show that, independent of erodibility or climate considerations, observed magmatic landform geometry implies a wide range of potential for erosion, due to trade‐offs between slope and drainage area in common erosion laws. Because the occurrence rate of magmatic events varies systematically with the volume of material emplaced, only a restricted class of magmatic processes is likely to directly compete with erosion to shape topography. Outside of this range, magmatism either is insignificant on landscape scales or overwhelms preexisting topography and acts to reset the landscape. The landform data compiled here provide a basis for disentangling competing processes that build and erode topography in volcanic provinces, reconstructing timing and volumes of volcanism in the geologic record, and assessing mechanical connections between climate and magmatism.