SFJCody
Mar 2 2004, 09:48 PM
I visited a place with beds similar to the Meridiani outcrop last year. Rich in jarosite and shot through with tabular crystals.
I don't have any webspace right now though. If anyone is willing to host an image of mine showing this place I will be semi- eternally grateful :-)
djellison
Mar 2 2004, 09:51 PM
You can add images as attachments to posts in the forum
Doug
SFJCody
Mar 2 2004, 09:57 PM
I can? Excellent... but I don't see a browse button:
'If the admin has enabled it, you will also see a file attachments option, this will allow you to attach a file to be uploaded when making a post. Click the browse button to select a file from your computer to be uploaded. If you upload an image file, it may be shown in the content of the post, all other file types will be linked to.'
Oh, and the image is a 412kB JPG
djellison
Mar 2 2004, 10:10 PM
Under the emoticons on a new post? I'll check the admin settings for it - but I'm fairly sure I had it turned on specifically for the purpose of people showing pictures
Infact - just checked the settings - upload is set to on for all members in all groups.
Doug
SFJCody
Mar 2 2004, 10:16 PM
No... under the emoticons I see 'Add reply' and 'preview post'
lars_J
Mar 2 2004, 10:16 PM
Hmm, I don't see any way of attaching images...
djellison
Mar 2 2004, 10:29 PM
You dont get
?
Thats most odd - because it is turned on in the forum, I'll go do some googling on it
Doug
SFJCody
Mar 2 2004, 10:33 PM
I don't get 'file attachments' or 'options'
lars_J
Mar 2 2004, 10:44 PM
Nope, I see neither the "file attachements" nor the "Options" section.
SickNick
Mar 2 2004, 11:04 PM
Glad it's not just me. I couldn't find it either.
Gave up weeks ago and link stuff in from another site I *can* post pictures to.
Is it Browser-specific? I use Mozilla (1.3.1)
djellison
Mar 2 2004, 11:40 PM
I'm on Firefox - so it's not the browser.
I'll chase it up tomorrow.
Doug
djellison
Mar 2 2004, 11:55 PM
Hee hee - I am SUCH a spaz
You we all set to be able to upload images, that bit was fine
Just the maximum attachment size was - ahem - zero kb
Changed it to 2 meg - but try and keep it at a reasonable size. If I see a sky-rocket of bandwidth because people are using here as a file dump to post links to on other forums etc, then I'll turn on the old registered members only visibility
Doug
SFJCody
Mar 3 2004, 08:58 AM
Let's see if this works...
Gray
Mar 5 2004, 01:00 AM
Very interesting exposure. What do you know about the depositional environment of sediments? Is the jarosite a surficial weathering deposit? It didn't seem as obvious in the images where you had scraped beneath the surface.
SFJCody
Mar 5 2004, 02:34 PM
It's fairly insubstantial- I guess it's surficial.
I don't know much about the circumstances surrounding the deposition of the jarosite bed.
From a website with a scrap of information about an exposure of the Wealden jarosite that appears a few dozen miles away:
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"Oxidation of the iron sulphide pyrite can produce sulphuric acid and iron oxides. Reactions lead to the formation of the hydrated iron-bearing sulphate jarosite (with either sodium, potassium or ammonium). This yellow surface encrustation is often mistakenly referred to in old literature as " sulphur ". It is slowly soluble in water and is washed away to some extent by heavy rain but develops again in fairly dry weather. "
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The exposure in my photos was only revealed in the past couple of years. The cliffs in the area are prone to slumping and subsidence in the winter and sometimes large areas are inaccessible.
Below the orange jarosite crust the material is two thin beds of grey clay with bright yellow patches (best seen in photo 3) separated by 20cm of lignite (the blackish stuff in photo 1). The gypsum cystals are occur in both beds in both the yellow and grey areas. I found a lot of them stuck to the underside of the lignite.
Gray
Mar 5 2004, 04:39 PM
Very interesting. Thanks for the follow-up. It's curious that the jarosite is produced there by reactions between iron oxide and sulphuric acid; and only during the dry spells.
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