Publication Date:
2018-06-21
Description:
On the Moon, the low-density crust exerts a strong filter to magma ascent. Many lunar craters are filled with mare, and evidence of pyroclastic activity and shallow magmatism is often located within craters called floor-fractured craters (FFCs). Interpreting quantitative observations on mare-filled craters and FFCs based on mechanical models, we show that a surface unloading caused by an impact crater provides a driving overpressure to the magma stalling at depth. This overpressure counterbalances the melt negative buoyancy, favoring its ascent through the crust. Providing a large unloading and a thin crust, magma can ascend up to the crater floor. FFC characteristics are consistent with a magma denser than the crust by 200–300 kg/m3 and an elastic lithosphere thickness larger than 70 km. Our study suggests that small impact cratering likely induced magmatism and thereby crustal evolution in the early times of terrestrial planets. ©2018. American Geophysical Union. All Rights Reserved.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
