Compositional evidence regarding the influx of interplanetary materials onto the lunar surface

Autor: William V. Boynton, John T. Wasson, Chen Lin Chou, Philip A. Baedecker
Rok vydání: 1975
Předmět:
Zdroj: The Moon. 13:121-141
ISSN: 1573-0794
0027-0903
DOI: 10.1007/bf00567511
Popis: Siderophilic element/Ir ratios are higher in mature lunar soils from highlands sites than in those from mare sites. It is suggested that the population of materials responsible for the early intense bombardment of the moon had high ratios and that the population responsible for the essentially constant flux has low ratios. Arguments are summarized against the viewpoint that the siderophiles in most highlands breccias originated in basin-forming projectiles. Differences in mature soil siderophile concentrations at the Apollo 14 and 16 sites indicate a substantially greater concentration at the latter site immediately following the Imbrium event. Siderophile concentrations are used to estimate mean regolith depths at the landing sites. The long-lived flux is calculated to be 2.9 g per cm per aeon averaged over the past 3.7 aeons. Consideration of the relationship between mass fluence and time indicates that the mass flux decreased with a half-life of about 40 million years immediately following the Imbrium event.
Databáze: OpenAIRE
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