- Solomon, Sean C;
- Aharonson, Oded;
- Aurnou, Jonathan M;
- Banerdt, W Bruce;
- Carr, Michael H;
- Dombard, Andrew J;
- Frey, Herbert V;
- Golombek, Matthew P;
- Hauck, Steven A;
- Head, James W;
- Jakosky, Bruce M;
- Johnson, Catherine L;
- McGovern, Patrick J;
- Neumann, Gregory A;
- Phillips, Roger J;
- Smith, David E;
- Zuber, Maria T
Mars was most active during its first billion years. The core, mantle, and crust formed within approximately 50 million years of solar system formation. A magnetic dynamo in a convecting fluid core magnetized the crust, and the global field shielded a more massive early atmosphere against solar wind stripping. The Tharsis province became a focus for volcanism, deformation, and outgassing of water and carbon dioxide in quantities possibly sufficient to induce episodes of climate warming. Surficial and near-surface water contributed to regionally extensive erosion, sediment transport, and chemical alteration. Deep hydrothermal circulation accelerated crustal cooling, preserved variations in crustal thickness, and modified patterns of crustal magnetization.