During the rock cycle test pdf Apollo landing missions, 2,415 samples weighing 380. They range in age from about 3. 44 billion years old for rocks der
During the rock cycle test pdf Apollo landing missions, 2,415 samples weighing 380. They range in age from about 3. 44 billion years old for rocks derived from the highlands. Based on the age-dating technique of “crater counting,” the youngest basaltic eruptions are believed to have occurred about 1.
Most were photographed prior to collection to record the condition in which they were found. Earth to protect them from contamination. A combined total of less than one kilogram of material was returned. Primary igneous rocks in the lunar highlands compose three distinct groups: the ferroan anorthosite suite, the magnesian suite, and the alkali suite. The ferroan anorthosite suite is the most common group in the highlands, and is inferred to represent plagioclase flotation cumulates of the lunar magma ocean, with interstitial mafic phases formed from trapped interstitial melt or rafted upwards with the more abundant plagioclase framework. Fe ratios that are inconsistent with calcic plagioclase compositions.
Ferroan anorthosites have been dated using the internal isochron method at “circa” 4. The trace element contents of these minerals also indicates a KREEP-rich parent magma. The alkali suite spans an age range similar to the magnesian suite. The alkali feldspar may have unusual compositions unlike any terrestrial feldspar, and they are often Ba-rich.
These rocks apparently form by the extreme fractional crystallization of magnesian suite or alkali suite magmas, although liquid immiscibility may also play a role. 4 Ga, more or less the same as the magnesian suite and alkali suite rocks. In the 1960s, NASA researcher John A. O’Keefe and others linked lunar granites with tektites found on Earth although many researchers refuted these claims. According to one study, a portion of lunar sample 12013 has a chemistry that closely resembles javanite tektites found on Earth. The vitrophyres are dominantly glassy rocks that represent impact melt sheets that fill large impact structures. They contain few clasts of the target lithology, which is largely melted by the impact.
It may contain abundant clasts that reflect the range of lithologies in the target region, sitting in a matrix of mineral fragments plus glass that welds it all together. Some of the clasts in these breccias are pieces of older breccias, documenting a repeated history of impact brecciation, cooling, and impact. As noted above, the basin-forming impacts responsible for these breccias pre-date almost all mare basalt volcanism, so clasts of mare basalt are very rare. When found, these clasts represent the earliest phase of mare basalt volcanism preserved. Most of the rocks are stored in nitrogen to keep them free of moisture. They are handled only indirectly, using special tools. Moon rocks collected during the course of lunar exploration are currently considered priceless.