TERRESTRIAL PLANET LARGE IGNEOUS PROVINCES: INSIGHTS INTO PRIMARY AND SECONDARY CRUST FORMATION AND PERSPECTIVES ON EARTH (Invited Presentation)

Large igneous provinces (LIPs) on Earth are commonly thought of as huge deposits of effusive volcanic products emplaced regionally, over a relatively short period of time, and being closely linked to mantle dynamics, such as upwelling plumes or anomalous hot spots. Examples of LIP settings include continental flood basalt provinces, oceanic plateaus, volcanic margins, ocean basin flood basalts and large seamount chains. On Earth, the presence of plate tectonics operates to define, modify and obscure many LIPs environments. For example, upwelling plumes at divergent plate boundaries (e.g., Iceland) produce considerably different deposits than do mid-plate plumes (e.g., Hawaii). LIPs are common on most of the terrestrial (Earth-like) planets (e.g., Earth, Moon, Mars, Venus), but are often manifested differently and occur in different environments (e.g., Head and Coffin, 1997). Two key aspects of the planetary record help to provide insight into the origin and evolution of LIPs: 1) several planetary bodies other than the Earth (e.g., the Moon, Mars and Mercury) preserve a rich surface geologic record of the majority of Solar System history, and 2) these same bodies are one-plate planets, and thus their lithospheres have been stable relative to their interiors over the vast majority of their history. These facts mean that the Moon, Mars, Venus and Mercury not only preserve an excellent record of LIPs in space (their areal distribution over the planet), but this record is also preserved in time (the temporal flux of volcanism over geological history). We define, compare and contrast two types of planetary LIPs: 1) those that represent a global phase of volcanism over a short period of time (Hesperian Mars, Mercury smooth plains and Venus volcanic plains) and 2) those that form areally extensive and massive kilometers-thick deposits in localized low areas (usually large impact basins; Moon, Mars and Mercury) and regional highs (Tharsis and Elysium, Mars). We explore the implications for primary and secondary crust formation.

J. Head & M. Coffin (1997) Large Igneous Provinces: A Planetary Perspective, AGU Geophys. Mono., 100, 411-438.