Arabian Ammonite

**Hajar** · Dec 22, '09, 2:10pm

Yesterday, on a fine Arabian winter day (27 degrees C), I was hiking with a colleague over one of the southern foothills to the main Hajar Mountains, studying the structural geology. I took a photo of a spectacular graben and then turned to my right to come face to face with the monster Cretaceous ammonite shown below. This is a rare find in this area and will go to the local natural history museum. A complete surprise!

**Architeuthoceras** · Dec 22, '09, 2:39pm

Yesterday, on a fine Utah winter day (27 degrees F)...

Nice graben Hajar, looks alot like home in the summer.

That ammonite has the sculpture of a Prionocyclid or Collignonicerid, any idea on the ID ?

**DWhatley** · Dec 22, '09, 4:46pm

Thanks for adding your location

. Without the extra 'U''s in words of the Indians, Brits, Aussies and Kiwi's I was in a quandary as to where you might be located that has cuttlefish swimming about. Your location is unique among TONMOers - very, very cool (especially at 27 C).

What a terrific find. I am afraid I would never detect a fossil if it bit me (and that one looks like it was just staring at you and yet had not been discovered). Had I remained where I was born (upstate NY where the glaciers carved out a lot of the land), perhaps I would have learned to look but there are not a lot of fossils digs in the South East US.

**sorseress** · Dec 22, '09, 7:05pm

Is your Tonmo name based on the Mountain Range? Or was the mountain range named after you?

OB · Dec 22, '09, 7:39pm

A dream find, wow....

**Hajar** · Dec 23, '09, 11:06am

Beautifully done Kevin! The amazing thing is that it can be getting on for twice as hot during summer.

The ammonite is Cunningtoniceras multicostatum (Basse, 1940) - thanks to Jim Kennedy for the identification. I hope it will be displayed since it's quite imposing in person, 27 cm across with its striking horn-like tubercles. I'll pass it on to its new home on Saturday. Yes dwhatley and Ob, it was an exciting moment to first see it just sitting there. I looked away and then looked back again to be sure of what I was seeing.

A few more photos of the foothill jebels are attached. Each is like a lost world rising from the gravel plain. Hiking up the wadis we came across many prehistoric tombs, which give ages of 4470 to 4600 years where they have been dated. There's a photo below of one perched on a ridge.

Sorseress, Hajar is Arabic for "rock" or "stone mountains". The mountains reach 3000 m at Jebel Shams ("Mountain of the Sun") and there is an astonishing amount of wonderful geology to be seen up there as well as some huge views.

**sorseress** · Dec 23, '09, 3:26pm

Are those goats domesticated? The color variety would lead me to believe that they aren't native wild goats, but it's hard to imagine trying to raise goats in that environment. Much of the terrain looks like it could be found here in Arizona. Also, in photo #1 there appears to be a rectangular opening at the top of one of the peaks. Is that the entrance to one of the tombs? It looks far too regular to be naturally occurring.

**Hajar** · Dec 26, '09, 9:26am

Yes, domesticated (or perhaps feral). There are timeless scenes of shepherdesses with richly coloured clothes and long sticks watching over their goats in dry and forbidding settings in the mountains. I have yet to see the indigenous mountain-dwelling wild goat called the Arabian Tahr (http://www.environment.org.om/index/...&Extension=gif). I didn’t notice any tombs that high in Jebel Qusaybah.

I found some references to Triassic ammonoids in this area and I’ll take a look one of these days:
http://paleo.cortland.edu/globaltria...n%20ammos).pdf
http://sp.lyellcollection.org/cgi/co...tract/49/1/203

**Hajar** · Dec 29, '09, 1:17pm

So today after work I went looking for Triassic cephalopods. At a place called Al Aqil I found an outcrop of forereef breccias, probably earliest Jurassic in age, with large blocks of red Hallstatt-type Triassic (Norian) limestones enclosed. These are thought to be deposits of a seamount with reef facies developed on volcanics. Many ammonoids were visible along with orthocones and Aulacoceras guards plus a gastropod and some bivalves. Here are a few pictures. Good fun; I had never seen these before.

**Hajar** · Dec 29, '09, 1:25pm

and back to the Cretaceous - I started a sketch of the Cunningtoniceras. Not quite sure yet how this will turn out.

**DWhatley** · Dec 29, '09, 11:47pm

I think we need a TONMO art gallery, separate from our photos albums!

**Hajar** · Dec 31, '09, 10:36am

Thanks, but don't think this qualifies as art yet!

Before I head out for the evening here are a few pictures of pieces I brought back from the Trias trip.

**DWhatley** · Dec 31, '09, 3:10pm

What is the blue, it does not quite look like turquoise that we have out west.

**Hajar** · Jan 03, '10, 1:40pm

I think it's just some of the sparry calcite with a slightly bluish tinge.

I put a different head on the Cunningtoniceras and the beast doesn't look so friendly now.

**Architeuthoceras** · Jan 03, '10, 3:38pm

Looking good

Did you saw those fossils or is it just the way the weathered?

**Hajar** · Jan 04, '10, 3:17am

I polished these pieces, found loose in the scree, with fine (F400) silicon carbide (from a stone-tumbler kit belonging to the kids) on a piece of old picture-frame glass. The naturally weathered appearance can be seen in #9 above.

Blendinger (1991) documented the J. magnus, C. bicrenatus, H. hogarti and H.macer zones of the Norian in these rocks.

**Hajar** · Oct 15, '10, 2:47am

There's a note on the Cunningtoniceras here.

**DWhatley** · Oct 15, '10, 2:58am

Hajar,
When you say polished with the glass and silicone, do you mean that the silicone carbide is a grit and you put the grit on the glass and then rubbed the fossil around on the grit? Sorry, I have only used sand paper to polish acrylic tanks or to attempt a decent finish on wood for a tank stand or three

. Mother was into finding and tumbling semi-precious stones years ago but long after I was married so I never learned much about polishing rocks.