Non-KREEP origin for Chang'e-5 basalts in the Procellarum KREEP Terrane

Article

关键词: MARE BASALTS;    TRACE-ELEMENTS;    LUNAR;    VOLCANISM;    SR;    PETROGENESIS;    MOON;    REE;    CRYSTALLIZATION;    GENERATION;   

DOI  :  10.1038/s41586-021-04119-5

来源: SCIE

【 摘 要 】

Mare volcanics on the Moon are the key record of thermo-chemical evolution throughout most of lunar history(1-3). Young mare basalts-mainly distributed in a region rich in potassium, rare-earth elements and phosphorus (KREEP) in Oceanus Procellarum, called the Procellarum KREEP Terrane (PKT)(4)-were thought to be formed from KREEP-rich sources at depth(5-7). However, this hypothesis has not been tested with young basalts from the PKT. Here we present a petrological and geochemical study of the basalt clasts from the PKT returned by the Chang'e-5 mission(8). These two-billion-year-old basalts are the youngest lunar samples reported so far(9). Bulk rock compositions have moderate titanium and high iron contents with KREEP-like rare-earth-element and high thorium concentrations. However, strontium-neodymium isotopes indicate that these basalts were derived from a non-KREEP mantle source. To produce the high abundances of rare-earth elements and thorium, low-degree partial melting and extensive fractional crystallization are required. Our results indicate that the KREEP association may not be a prerequisite for young mare volcanism. Absolving the need to invoke heat-producing elements in their source implies a more sustained cooling history of the lunar interior to generate the Moon's youngest melts.

【 授权许可】

Free