Inference on the nature and the mass of Earth's late veneer from noble metals and gases

摘要: [1] Noble metals and gases are very sensitive to the late accretion Earth of asteroids comets. We present mass balance arguments based on these elements that indicate 0.7 − 2.7 × 1022 kg extraterrestrial bodies struck after core formation comets comprised less than 10−3 by impacting population. These results imply dynamics changed with time biogenic prebiotic molecules were not delivered but rather carbonaceous asteroids.