Formation ages and evolution of Shergotty and its parent planet from U-Th-Pb systematics

Large‐ion lithophile element fractionation during the early differentiation of Mars and the composition of the martian primitive mantle

“…The exact age of this differentiation event(s?) is unclear but is well in excess of 4.0 Ga (e.g., Chen and Wasserburg 1986;Jagoutz 1991;Harper et al 1995;Blichert-Toft et al 1999;Brandon et al 2000;Halliday et al 2001;Nyquist et al 2001;. Although crust formation continued after this date (for example, most SNC meteorites have crystallization ages <1.5 Ga), the mean age of the martian crust is probably approaching twice the mean age of the terrestrial continental crust and 4 times the mean age of the overall terrestrial crust (e.g., Jacobsen and Yin 2002;Hauck and Phillips 2002).…”

Martian xenon components in Shergotty mineral separates: Locations, sources, and trapping mechanisms

“…Model ages suggest that martian global differentiation, including core formation, occurred near 4.5 Ga, and was for the most part concurrent with the completion of accretion (Shih et al 1982;Chen and Wasserburg 1986;Jagoutz 1991). This resulted in a depleted mantle and an enriched crust.…”

High-spatial resolution U-Pb dating of phosphate minerals in Martian meteorite Allan Hills 84001

“…Phosphate minerals such as apatite and merrillite are common in extraterrestrial materials. They are important carriers of incompatible elements including REE, Th and U, and were used for leaching experiment (e.g., Chen and Wasserburg, 1986). However, because the phosphates are volumetrically minor and because their grain sizes are limited, minimally or non-destructive analytical methods must be used for accurate dating, even though enriched shergottites contain phosphate mineral grains up to several hundred micrometers.…”