Mars, Mercury, the Moon, and many satellites of gas giants Jupiter, Saturn, and Uranus, are scarred with giant impact basins that
record collisions from asteroids during the early history of the solar system. Giant impact basins, typically hundreds to thousands of
kilometers in diameter, are associated with distinctive morphological features, including multiple concentric rings, radially distributed
scour valleys, fractures and radial graben, crater chains, and large (>20 km in diameter) secondary craters. Impacts that formed giant
basins commonly resulted in deep excavation and fracturing of planetary crusts, forming conduits for later upward migration of
magma plumes and subsequent basin infilling with lava. For example, most giant nearside lunar basins that formed between 3.8 an
4.3 billion years ago are partly filled with basalt. The Serenitatis Basin contains a succession of layered extrusive units tha
collectively 2 to 4 km thick, 750 km in diameter, and 300,000 to 500,000
km in volume. Some giant impact basins are also associated
with antipodal features caused by propagation of compressive waves through the planetary interior. These features include hilly,
lineated, and jumbled terrain, as observed in areas antipodal to the Caloris Basin on Mercury. Swirled terrain and remnant
paleomagnetism are observed on the Moon in areas antipodal to the Imbrium Basin. In addition, some recent features on the Moon,
such as Ina, antipodal to the South Pole-Aitken Basin, are inferred to have been caused by degassing of volatiles (important materials
for sustaining human settlement) in areas of weak and fractured crust.
This articles is adapted from oral presentation at AAPG Convention, Denver, Colorado, June 7-10, 2009.