Morocco Stromatolite?

[Tidgy's Dad]

I bought this recently in Agadir for only $25 so I'm happy whatever it is.

It is said to be a stromatolite, though it may be just a desert rose of some type, though it's very hard and heavy, definitely not gypsum or barite.

Some sites on the net suggest precambrian, ranging from 2.6 down to .6 billion years old, depending where you look.

Some say Cambrian, some Ordovician and others Devonian or Cretaceous.

Any ideas anyone?

[Raggedy Man]

Definitely a stromatolite and a nice sized one!

Here's mine. It's from the lower cretaceous, Tagana formation.Ken-kem region. Ksar-es Souk, Morocco

[Auspex]

It's a lovely example! Certainly a good match for many of the Sahara stromatolite images I can Google up.

You are right, though, about the dating being all over the map...

[abyssunder]

Also from Morocco,one in my collection.

[Tidgy's Dad]

Definitely a stromatolite and a nice sized one!

Here's mine. It's from the lower cretaceous, Tagana formation.Ken-kem region. Ksar-es Souk, Morocco

20150713_155214.jpg

Yes, these Cretaceous ones are similar, but not as orange as the desert ones, altogether paler.

Thanks, nice looking one you have there.

[Tidgy's Dad]

It's a lovely example! Certainly a good match for many of the Sahara stromatolite images I can Google up.

You are right, though, about the dating being all over the map...

Thanks, it's a beauty, I checked every image I could find on Google for these orange ones and it is, as you say, rather conflicting.

My collection's arranged by geological period, so I don't know where to place it.

I'd love it to be Pre-Cambrian, but I don't honestly think it's that old, i've seen the Pre cam stroms from some areas here and they're much harder, massive and layered. Hmmm.

[Tidgy's Dad]

Also from Morocco,one in my collection. 100_4304a.jpg

That's beautiful!

Do you have a location and age?

[Auspex]

...My collection's arranged by geological period, so I don't know where to place it...

"Timeless" has a nice ring to it...

[Tidgy's Dad]

"Timeless" has a nice ring to it...

It does.

So in my music collection, then?

[Auspex]

There might be a paper out there addressing these. What do we have to go on, location-wise?

[ZiggieCie]

Tidgy's Dad, we are going to love seeing your collection of "REAL" fossils "FROM" Morocco.

PS. I love your Fez. I have thought those were great hats since I was a kid, I'm 63 now, and they are still great.

Ziggie

[Tidgy's Dad]

There might be a paper out there addressing these. What do we have to go on, location-wise?

Just that it's from the Sahara.

The guy in the shop in Agadir was vague, but I've seen plenty like this here and on the net.

It's real, but I'm just not sure about the age.

[Ebo]

I'm sorry to deceive you, but these aren't stromatolites, but structures that are formed through rich mineral water deposition.

I've had a long discussion with a colleague that extract these structures from the Moroccan site, and at this time I believe that are stromatolites too.

He says not, I'm saying yes...

He show me some pictures from the extraction site... then I was convinced that aren't stromatolites.

Here are some pictures that show these concretions.

It is interesting to see also that doesn't exist any internal layered structure when you cut and polish these spherical structures (see image below), growing structures that are in general well visible in "normal" stromatolites.

I haven't this paper, but these structures are described in this way:

According to Lavocat (1954b), fossils are sometimes concentrated at the surface by erosion but most of these concentrations have now vanished as a result of continuous surface collecting. At these more ephemeral localities fossils are associated with the kerkoub facies (Fig. 4C), characterized at the surface by concentrations of sandstone spheres that range from around 2 to 10 cm in diameter (Lavocat, 1954).

Lavocat, R., (1954). Reconnaissance géologique dans les Hammadas des confins algéro-marocains du Sud. Notes et Mémoires du Service Géologique du Maroc 116. 147 p.

At my knowledge, the only commercial Moroccan Precambrian stromatolites are coming from the Tachgagalt Formation, in the Ouarzazate Supergroup (Amane n'Tourhart, Ouarzazate), like the Collenia specimen shown here (from my collection):

Enrico

Edited July 14, 2015 by Ebo

[Tidgy's Dad]

Stromatolites with definite layered structures are found at Tiout, Agdz and Imgur, (maybe not all commercial sites).

The sort you show are the alleged Cretaceous pale ones found at Saf-saf, Merzouga and Khenifra.

Others come from Erfoud and in the Sahara and Western Sahara.

You may well be right that they are just concretions, but if Lavocat in 1954 suggested these concretions were mostly gone due to surface collecting, why are these things still so abundant? I think in 1954, most Moroccan localities were still unknown.

However, my logic is telling me they are probably not fossils, my heart still hopes they are.

Thank you for your information.

[Auspex]

The question really is whether these accreted by biological or lithological process. It may be pretty hard to tell.

[Ebo]

Auspex, this is an interesting question.

I'm pretty sure that bacteria can be present during the deposition of CaCO₃ or other minerals, functioning as catalytic.

But in this particular situation, the sandstone is quite an unusual and raw matrix for the stromatolites sensu strictu as we know.

These structures (collenia, cryptozoon, thrombolites, oolithes...) develop in general in quiet environments (lagoons -but not only like the oolithes/onchoids-), with hypersaline water, in general lime or very fine dolomite sediments are the principal component of the matrix, and not sand that is more related to detritic presence, not very well appreciated by the algal mats...

This is an open question and very interesting to analyze (even taken in account in astrobiology, in searching for extraterrestrial life in other planets).

Enrico

[Tidgy's Dad]

This picture seems to show layering.

[Tidgy's Dad]

And this one.

[Ebo]

I bought some years ago this "stromatolites" coming from the same site, and I believe that was a real stromatolites too (before the discussion with the guy working on place and send me the picture that I show you):

You can see the evident layering due to the atmospheric elements erosion, the "bubbled surface" that remember well the "growing gems" of some algal mats and the smoothed general surface.

Just at today I haven't seen any official paper published about these "stromatolites", nor the exact location where these forms come from; may be you can greatly help us to localize the site with a latitude/longitude point.

This is really useful to find the geologic formation (then the correct age) and if we are lucky the environment deposition if the geologic map of Morocco contain the related information.

[Tidgy's Dad]

I don't have the location, though there are several supposed localities for this type of 'fossil'.

The greyer ones like yours are supposedly from further north and the yellowish ones, like mine from the Sahara.

I will look into it.

[Bobby Rico]

Hi Adam,

 

So pleased I found your post on Moroccan "stromatolites" . Very interesting thank you.

I found my own specimen that Mrs R gifted to me , a long time ago.  I believe it is from the Sahara desert.  Been very dyslexic I am struggling to comprehend some of this thread. My question is to you have you done anymore research on this subject? I think you mentioned somewhere else that this maybe a similar form to desert rose structures?

 

 

Looking at the side of my " ufoo ( unidentified form of Orange) its no really that clear but it has a very slite banding or lamination. Anyway pal I hope your well and find your way to this thread again soon .

 

All the best Bobby

 

 

 

 

 

Edited September 6 by Bobby Rico