The moon: sources of the crustal magnetic anomalies.

摘要: Previously unmapped Apollo 16 subsatellite magnetometer data collected at low altitudes over the lunar near side are presented. Medium-amplitude magnetic anomalies exist Fra Mauro and Cayley Formations (primary secondary basin ejecta emplaced 3.8 to 4.0 billion years ago) but nearly absent maria craters Copernicus, Kepler, Reiner their encircling mantles. The largest observed anomaly (radial component ∼21 gammas an altitude of 20 kilometers) is exactly correlated with a conspicuous light-colored deposit on western Oceanus Procellarum known as γ. Assuming that γ source body estimating its maximum average thickness 10 meters, minimum mean magnetization level 5.2 ± 2.4 x –2 electromagnetic units per gram, or ∼500 times stable most returned sample, calculated. An age for emplacement ≤ 2.9 inferred from photogeologic evidence, implying crustal materials must have continued period exceeding 1 years.