Talk:Moon rock/Archive 1

First post
The intro to this article bugs me. Anyone any comment on my changing it from


 * Moon rocks is the name that has been applied to the 382 kg (842 lbs.) of rocks and other samples collected during the Apollo program missions to the Moon. A total of six Apollo landings occured, and during the surface excursions 2,415 samples were taken. (The large majority were collected during the Apollo 15, 16, and 17 landings.) In addition, the Soviet Union sent three automated spacecraft to the Moon that returned an additional 301 g (0.66 lbs.) of samples.

to


 * ''Moon rocks defines the 382 kg (842 lbs.) of rocks and other samples collected during the Apollo program missions to the Moon. Six Apollo landings occured, and during the surface excursions 2,415 samples were taken, the majority by Apollo 15, 16 and 17. As well, three Soviet Union Luna spacecraft returned from the Moon with an additional 301 g (0.66 lbs.) of samples.

Moriori 21:12, August 6, 2005 (UTC)


 * Surely the collected rocks are the source of knowledge of the rocks on the actual moon, but I don't suppose "moon rock" can be defined as rock collected from the moon. Rocks still on the moon, or anywhere in the universe, are also moon rocks. Moon rocks should be defined as "rocks originating from the moon", or similar. The scope of this article should either be expanded or the article moved to "rocks collected from the moon", or similar. // habj 08:22, 3 October 2006 (UTC)

Suggestions for improvement before nominating as a Good article
I think that this article is a very nice start, and have a few comments on how it could be improved to good article status. Lunokhod 14:41, 24 November 2006 (UTC)
 * As it is now, this article has no sections. Subsections could include discussions concerning "collection" on the Moon, "curation" on Earth, a summary of the different types of rocks, and perhaps a summary of what has been learned about the Moon as a result of the samples.
 * More discussion should be given to the Luna samples
 * While I don't think that this is the place to discuss all the geochemical characteristics of the rocks, very short descriptions could be given for the "magnesian", "alkali", and "ferroan anorthosite suites. Very simple descriptions for the types of "rock" returned, such as "soil", "fines", "breccia", "impact melt", etc. could be listed and breifly defined.

Age of the rocks???
The article states that:

"In general the rocks collected from the Moon are extremely old compared to rocks found on the Earth. The youngest of the rocks is older than the oldest rocks seen on Earth. They range in age from 3.2 billion years from the basalt samples from the lunar mares, up to 4.6 billion years in the highlands. As such they represent samples from a very early period in the formation of the Solar System."

But how on earth (or on the moon) does anyone know the age of the rocks? It's not like anyone can carbon date them or anything. If the article's gonna talk about their age, then it should at least say something about how we know (or at least guess) how old they are!
 * Hi there 172.208.53.140. I'm not sure of your question. Why can't they be carbon dated, or otherwise dated? Moriori 08:04, 30 September 2005 (UTC)


 * Carbon dating has too short of a half-life for dating lunar rocks. I believe scientists used longer-lived radioactive isotopes, measuring such ratios as Rubidium-87/Strontium-87, etc.  &mdash; RJH 22:24, 31 October 2005 (UTC)


 * Please become more informed. C14 dating has nothing to do with rocks. It is used on organic material. Also the half-life is relatively short such that with current technology (note the year I'm writing this; 2006) the limit for dating such material is around 80,000 years. With rocks you use radiometric dating methods on elements such as radioactive potassium, rubidium, or uranium. —Preceding unsigned comment added by 24.56.193.228 (talk • contribs)


 * Fine, fine, there's no such thing as a carbon *COUGH*diamond*COUGH* rock. :-P &mdash; RJH 17:24, 21 April 2006 (UTC)

Further to age of the moon rocks - the highlands! The article purports them to be up to 4.6 billion years old, whilst the wiki on the solar system states that the solar system is 4.567 billion years old (by dating meteorites). I guess that the former figure has suffered from rounding because the rocks cannot be older then the solar system. Has anyone a more accurate figure for this?

Moon rocks are dated using a variety of techniques, most commonly Sm-Nd isochrons (works well for old rocks with plag and pyroxene) and various U-Pb methods. K-Ar and Ar-Ar are commonly used for mare basalts (don't work well on highland rocks). Also zircons are dated using U-Pb methods; zircons are found in the granitoid clasts (rare) and also in the regolith. It is also possible with several of these methods to determine model ages, which date age of separation of the source or sample from a pre-existing uniform source - commonly taken to be same as chondritic meteorites in isotopic composition. The 4.6 Ga age is rounded up from age for condensation of solar nebula based on Pb isotopes. There is a formation interval that can be estimated using short-lived Xe and Al isotopes. This is all discussed in some detail in Brent Dalrymple's book "The Age of the Earth" Geodoc (talk) 05:00, 16 February 2009 (UTC)

Table showing basalt composition
There's a problem with the table showing basalt composition. The row with high titanium content basalt adds up to more than 100 %, which is absurd. Could someone knowledgeable, please, correct that? Thanks. (4:34, 21 March 2009) —Preceding unsigned comment added by 94.253.144.191 (talk)


 * Hmm, good point, it does seem like more than can be accounted for by round-off error (105%). It seems to have been added on Feb 6, 2006 as a move from the Geology of the Moon article.  User:Lunokhod did the move and seems to be something of an expert in the field, but has not been working on the project since 2007.  We should in any event find a source for this information.  Any other thoughts?  Best, --TeaDrinker (talk) 05:00, 21 March 2009 (UTC)