[tony6789]

Where does sand come from that is simple when water bangs against rocks it weres them down a little. That little bit that came down is sand

- Big T

[tonycsm]

Hi Neilep,
          basically sand is formed from the erosion of mountains ie: the rock cycle usually starts from mountain building ( either plate collisions or intrusive material ( granite etc) into country rocks then erosion/weathering of both existing rocks and intrusions and finally with transportation and deposition. However, this is a very simplified explanation but has absolutely nothing to do with man's intervention, unless he (or she) was around over a billion years!

The sand most of us see around our coastlines in the UK for instance are formed mainly from felsic materials such as the volatiles of granitic type intrusions ( quartz and feldspars which are the last minerals to form from molten magma during it's cooling process which intrudes into country rocks) usually give a fine lighter colour because of their mineral content, but there are many other sources of material as mentioned in other members postings which form different sands ( some contain bio clastic material - skeletal etc). Material scraped up and re-deposited due to glacial movement also produces very different, often very course sands untypical of the normal weathering processes.

Eventually, all weathered material will be buried in our oceans and through diagenesis, form new rocks. The lithology will depend on the depth of water mineral content and the depth of burial.

Deserts are usually indicative of sub-equatorial regions of the world and ancient desert sands can be found in Britain, typically of Devonian and Permian periods, most likely due to the plate-techtonic movement which would place what we now call Britain, a little above and below the equator during the periods mentioned, similar to the latitude of the Sahara of today.

This can be confirmed by the coals found in Britain which were formed from tropical vegetation of paleo-equatorial regions during the Carboniferous period ( which sits between the Devonian and Permian periods).

I did my university disertaion on the Carboniferous Cyclothems of the Dinatian / Namurian period of Northern England - though not exactly relative to deserts, it explains the relationship of rock cycles due to erosion, sea transgressions and regressions and the rocks that form from these processes and a worthwhile read for those interested. These cycles formed a repeated pattern and I noted at least seven of these in the area I investigated were produced during the periods I mentioned, which are quite short in relative geological time, so it gives an insight into the cyclicity of the rock cycles and the conditions of the time of deposition.
 
Hope this info may help but it is only a very basic elementary explanation.

Tony

[Ray hinton]

all i know is that loads of this eroded rock turns up in my chips at the beach.
hey,why arent they called eroded-rockdals.

[toad1]

I just noticed this site by searching on grains of sand on earth, it is a fact I constantly bore people with.  Anyway all you clever people, well I do have an MSc but that was more by luck than judgement, the best beer is in the South, its just fizz North of Watford.

Talking about grains do you realise there are 'orrible crawly things just like you and me up there worrying about their mortgage and sailing handicap !!

[razorbill]

I was strolling along my local beach the other day when I heard a female voice calling for help,I was surprised to find a gorgeous looking girl buried up to her neck in SAND! "Please get me out" she cried, Oh righto I said....but whats in it for me?,SAND she replied!

[time-cop]

it looks like sand comes from more than one source,erosion of rocks,parrot fish poop,and people scratching i love tracy,or the like in stone,if you know chesil beach dorset,you will know that the pebbles at the eastern end of the beach are v-large,at west bay,14 miles away to the west,are tiny,almost sand,due to the seas action,and currents,a very graphic example for anyone.

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