Talk:Greensand

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[edit] A few points

Is there evidence for Greensand layers being narrow? The only greensand deposits that I know of are in the order of 100's of feet thick.

Is there evidence for Greensand being associated with chalk world wide? I only know of this assocition in NW Europe and Eastern America. As these were a single entity in the distant past I don't feel they can be used to justify world wide without a seprate deposit somewhere else. Do any deposits of this nature occur anywhere else?

Was that picture taken relatively soon after the road cutting was made? If not it isnt Greensand, although what looks like clays above suggest it certainly could be. Exposed Greensand rapidly oxidises to a yellowish colour. It should be noted that exposed greensand in not usually green. --LiamE 17:33, 20 September 2007 (UTC)

Liam, the trouble here is that quite a number of sources have been cited, and unless you have actually read and verified the points for or against your contention, you can't actually disprove anything. Can you not request these publications in your local library/ies, they can often get them from far afield if you put in a request. It is difficult to make a point, if you want to avoid being accused of doing your own research which would of course be discounted immediately bearing in mind Wikipedia's policy. What would help most would be the odd blockquote from one of these sources, that actually says that greensand in association with chalk is relatively rare and not to be found the world over. Dieter Simon 01:00, 21 September 2007 (UTC)

The only thing I have been able to find is the EB version of 1911 [1] which states "...Lower Greensand and Cambridge Greens, a local phase of the base of chalk..." Then it goes on to discuss various forms of sand/greensand. Further it mentions "...and it appears again beneath the northern outcrop of the Chalk in Berkshire, Oxfordshire and Bedfordshire". Dieter Simon 01:26, 21 September 2007 (UTC)

Yes a number of sources have been cited but none seem to cover the points I have raised. Feel free to point out which ones do if I have missed anything. And no, it not for me to disprove what has been written it is for the editors who wish claims to be included to cite references for them. EB 1911... poor source for anything invovling even vaguely involving plate tectonics as it was not discovered for 50 years, so let's leave that alone. Having done a bit of digging and reading since my last post I think I have answered 2 of the 3 for myself though. There seems to have been a bit of a crossover between talk of greensand in general and economically viable greesand with no clear distiction between the two. Typical greensands contain a little (2 percent or so) glauconite whereas economically viable greensand is 90ish per cent glauconite which will of course be a small fraction of entire greensand deposits. This quells my fears over the photo as it is most likely a high glauconite deposit as opposed to the more normal greesands that I am familiar with. It also answers my querey over the "narrow" bands which are later descibed as being up to 350ft thick! The article will need a minor adjustment so as not to confuse. As for my challenge on worldwide I am very puzzled by your reply. Are you seriously saying that deposits from Cambridge to Oxford can be used to justify the word worldwide? The greensand/chalk formation of southern England (and indeed across into continental Europe) is a single "local" deposit - even if it is a few hundred miles across. The only other place I have seen evidence of the association of greensand with chalk is eastern North America. Now if that were a seperate entity worldwide might be fine, but clearly as they were laid down as a sinlge entity with the European deposits I am having trouble with worldwide. Does this formation occur in South America, Africa, Asia or anywhere else? If it doesn't, "worldwide" is clearly not appropriate. --LiamE 19:10, 21 September 2007 (UTC)

Yes, I know, but what I meant was, we don't know what these cited sources say because they are book citation, and if we can't get hold of these books we are going to be stumped. I always think if books are being cited there should be some kind of quotes/blockquotes which cite details pertinent to the text of the article. As it is no-one knows what is actually being said in the books.

Also, you seem to know an awful lot about greensand, but must beware of using your own knowledge, perhaps obtained from your own research citing it. There has to be a text one can compare with the facts you are presenting, otherwise you will be accused of doing your own research which I am afraid isn't possible due to the Wikipedia precepts. Don't forget I know very little about greensand, but that isn't the point. I will write an article citing books and other articles only, and if I have gleaned anything from other sources I must cite these sources. That is really what it is all about. I don't dispute your facts but you must cite the source where you found these facts.

So, if you can cite where you found the fact that greensands contain a little (2 percent) glauconite, whereas viable greensand has 90 percent then you must it in the article but only with the citation of the sources where you found these facts. You cannot just say this is so when in fact you cannot verify that it is so. That is why I ever tried to point you to the only sources I was able to find in all this long discussion.

You can only disprove facts in the article by citing sources which say the contrary. I am afraid this is all I can say in this discussion, not only on this subject but also on North Downs, South Downs, Leith Hill, chalk, etc. You can't say I didn't try. Dieter Simon 00:36, 22 September 2007 (UTC)Dieter Simon 00:46, 22 September 2007 (UTC)

From "Arkansas Geological Survey" - "Presently, in the United States, economical greensand deposits contain at least 90 percent glauconite"

From "http://www.maden.hacettepe.edu.tr/dmmrt/dmmrt521.html" -

greensand

a. An unconsolidated marine sediment consisting largely of dark greenish grains of glauconite, often mingled with clay or sand (quartz may form the dominant constituent), found between the low-water mark and the inner mud line. The term is loosely applied to any glauconitic sediment. AGI

b. A sandstone consisting of greensand that is often little or not at all cemented, having a greenish color when unweathered but an orange or yellow color when weathered, and forming prominent deposits in Cretaceous and Eocene beds (as in the Coastal Plain areas of New Jersey and Delaware); specif. either or both of the Greensands (Lower and Upper) of the Cretaceous System in England, whether containing glauconite or not.

The fisrt source is already cited in the article. From reading that it is a simple step to deduce that not all greensand is economically viable and therefore there is greensand with lower glauconite concentrations. The 2pct glauconite figure I found is superceeded by the above quote which suggest some greensands contain no glauconite. The second source above makes the distinction between the two types of greensand clear to my mind and a small rewrite of the article is in order to make that distinction. As to my "worldwide" point I still have seen or read nothing to justify the word, though of course this may be due to systematic bias as I am far more likely to read sources in Eglish which are most likely to come from Britain or North America. --LiamE 19:25, 22 September 2007 (UTC)

If you are sure you can rewrite the article, then do so with the necessary sources cited, and if there is nothing you can find on what is in the article already, then you will have to ask editors for their fact sources. Don't just remove these items from the article, ask people to cite. They may well have these substantiations but may have forgotten to include them. Refer to the particular items and ask for "facts". This is what it's all about, sorry, I know it's some extra work. If your write it well with sources provided, it will be worth it. Dieter Simon 21:33, 22 September 2007 (UTC)