  The Oceanus Procellarum region, characterized by its vast basaltic plains and
pronounced volcanic activity, serves as a focal point for understanding the
volcanic history of the Moon. Leveraging the Gravity Recovery and Interior
Laboratory (GRAIL) mission data, we imaged the magmatic structures beneath the
Oceanus Procellarum region. Our 3D density models uncover pronounced linear
magmatic structures along the Procellarum's western border and significant
intrusions within the northern and southern Marius Hills. Crucially, they
reveal three narrow near-horizontal sheeted magmatic structures, 80-150 km
long, extending from near-surface to 6- 7 km depth, which we identified as
sill-like magmatic conduits. These magmatic conduits connect the Marius Hills'
northern and southern intrusions and bridge them with the Procellarum's western
border structures. These discoveries suggest that sill-like magmatic conduits
likely serve as central pathways facilitating magma transport across various
volcanic systems and furthermore indicate widespread magmatic connectivity
beneath the Oceanus Procellarum.
