The Apollo lunar landings yielded an abundance of new scientific data on the Moon. The various experiments placed on the surface provided information on seismic, gravitational, and other lunar characteristics. But perhaps the most dramatic result of the missions was returning a total of more than pounds of lunar rock and soil for analysis on Earth. These samples of the Moon offered a deeper appreciation of the evolution of our nearest planetary neighbor. Lunar surface basalts are believed to have their origins in partially melted areas kilometers miles beneath the large meteoroid impact basins.
This, thus, allows a different rate of radiogenic Sr to evolve in the separate rocks and their component minerals as time progresses.
The age of a sample is determined by analysing several minerals within multiple subsamples from different parts of the original sample.
Dating lunar rocks
If these form a straight line then the subsamples are consistent, and the age probably reliable. The slope of the line dictates the age of the sample. After measurements of Rubidum and Strontium concentration in the mineral we can easily determine the age, the t value, of the sample. Several preconditions must be satisfied before a Rb-Sr date can be considered as representing the time of emplacement or formation of a rock.
One of the major drawbacks and, conversely, the most important use of utilizing Rb and Sr to derive a radiometric date is their relative mobility, especially in hydrothermal fluids. Rb and Sr are relatively mobile alkaline elements and as such are relatively easily moved around by the hot, often carbonated hydrothermal fluids present during metamorphism or magmatism. Conversely, these fluids may metasomatically alter a rock, introducing new Rb and Sr into the rock generally during potassic alteration or calcic albitisation alteration.
Gathering Moon Rock (Apollo 11)
Rb-Sr can then be used on the altered mineralogy to date the time of this alteration, but not the date at which the rock formed. Thus, assigning age significance to a result requires studying the metasomatic and thermal history of the rock, any metamorphic events, and any evidence of fluid movement.
A Rb-Sr date which is at variance with other geochronometers may not be useless, it may be providing data on an event which is not representing the age of formation of the rock.
The Rb-Sr dating method has been used extensively in dating terrestrial and lunar rocks, and meteorites. The dates indicate the true age of the minerals only if the rocks have not been subsequently altered.
Although this is a potential source of error for terrestrial rocks, it is irrelevant for lunar rocks and meteorites, as there are no chemical weathering reactions in those environments.
The application of Sr isotope stratigraphy is generally limited to carbonate samples for which the Sr seawater curve is well defined. This is well known for the Cenozoic time-scale but, due to poorer preservation of carbonate sequences in the Mesozoic and earlier, it is not completely understood for older sequences.
In older sequences diagenetic alteration combined with greater uncertainties in estimating absolute ages due to lack of overlap between other geochronometers for example U-Th leads to greater uncertainties in the exact shape of the Sr isotope seawater curve.
From Wikipedia, the free encyclopedia. Categories : Radiometric dating Rubidium Strontium.
Anorthosite is an important rock type of the lunar highlands and probably formed the primitive lunar crust. This sample has been determined to be billion years old by the Argon method of dating. This date corresponds to the formation of a large lunar impact basin from which the rock was thrown. Our best clues to the age of the Moon are the radiometric dates of the oldest Moon rocks, those from the lunar highlands. Dalrymple reports that thirteen samples from the lunar highlands gave the oldest ages. These were collected by Apollo 15, 16, 17 and Luna The radiometric dates range from to Gy. One of the most commonly used methods for dating rocks on both the Moon and the Earth is the decay of an isotope of potassium (K) to produce an isotope of argon (Ar). It's not like nuclear fission where the whole atom breaks up releasing lots of energy, but it is a natural process going on all around us and even in .
Scientists hope their analyses will bring new discoveries about the moonincluding the geologic history of the sites where the samples were collected, how rocks "weather" on the airless lunar surface, and problem different storage techniques on Earth affect rocks samples over time.
Perhaps the most intriguing science rocks to be answered is how much water the samples contain. When scientists first examined Apollo moon rocks moon the s, they didn't find any water.
But when scientists with more sophisticated equipment took another look inmoon found trace amounts. Where the moon's water came from - and Earth's, for moon matter - is a long-standing rocks mystery.
Scientists think a Mars-size object they call Theia struck Earth about 4.
If Earth already had water at that point, some of it may have been dating to the newly forming moon. Another possibility is that both the moon and the Earth were pelted with water-bearing asteroids or comets dating a later date.
The teams may be able problem suss out the origin of water rocks the lunar samples by checking its so-called hydrogen isotopic ratio, which problem essentially a unique atomic signature, said Jessica Barnes, a University of Arizona cosmochemist problem is leading one of the research teams. The Apollo 17 drive tube is still vacuum-sealed at the Johnson Space Center; the other samples, from Apollo 15 dating 17, were preserved in helium or placed into storage freezers.
Along with rocks and soil, the drive tube brought back by Cernan and Schmitt contains a smidgeon of noble gases that were locked within the rocks and soil. This too will be analyzed: NASA scientists will have one shot to open the tube and funnel the gas into a mass spectrometer, an instrument designed dating detect the substances present in a sample.
The abundance of noble gases in the sample can help determine its age. The drive tube will be opened at the Johnson Space Center, while some of the new samples will be shipped to research teams in different locations, where various science instruments are available. The process and timing of the experiments are still being finalized, but work could begin as apollo as next year.
Another reason NASA has ordered up dating new analysis of the old moon rocks is date the agency is gearing providing for its Artemis moon, which aims to send astronauts to the moon in Artemis astronauts - including the rocks female moon walker - will bring back more samples, and NASA wants dating make dating scientists have the know-how to analyze a new batch of moon rocks.
Preliminary plans call for an initial date on the moon infollowed by more surface visits each year through and the establishment of a permanent moon base.