Arabian Ammonite

Discussion in 'Cephalopod Fossils' started by Hajar, Dec 22, 2009.

  1. Hajar

    Hajar Haliphron Atlanticus Registered

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    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!
     

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  2. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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

    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 ?
     
  3. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    Thanks for adding your location :wink:. 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.
     
  4. sorseress

    sorseress Colossal Squid Supporter

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    Is your Tonmo name based on the Mountain Range? Or was the mountain range named after you? :smile:
     
  5. OB

    OB Colossal Squid Staff Member Moderator

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    A dream find, wow....
     
  6. Hajar

    Hajar Haliphron Atlanticus Registered

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    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.
     

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  7. sorseress

    sorseress Colossal Squid Supporter

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    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.
     
  8. Hajar

    Hajar Haliphron Atlanticus Registered

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    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/list3.php?categoryId=326&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/globaltriassic/Bull41/08-Bruehwiler (smithian ammos).pdf
    http://sp.lyellcollection.org/cgi/content/abstract/49/1/203
     
  9. Hajar

    Hajar Haliphron Atlanticus Registered

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    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.
     

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  10. Hajar

    Hajar Haliphron Atlanticus Registered

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

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  11. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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

    Hajar Haliphron Atlanticus Registered

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    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.
     

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  13. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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

    Hajar Haliphron Atlanticus Registered

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    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.
     

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  15. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Looking good :notworth:

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

    Hajar Haliphron Atlanticus Registered

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    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.
     
  17. Hajar

    Hajar Haliphron Atlanticus Registered

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    There's a note on the Cunningtoniceras here.
     
  18. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    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 :grin:. 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.
     
  19. Hajar

    Hajar Haliphron Atlanticus Registered

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    Yup, that's exactly how it's done. A very good plan if you want to look at the details of fine-scale structures.
     
  20. DWhatley

    DWhatley Cthulhu Staff Member Moderator

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    :read: your newsletter.

    Any chance of getting a copy of the video? Subtitles OK :grin:
     

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