Fossil Hunting Trip

Discussion in 'Cephalopod Fossils' started by Architeuthoceras, Jul 16, 2003.

  1. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    Hi Folks,
    When it gets too hot in the great western desert, we go fossil hunting in the great Rocky Mts (about 105F in the valley and about 75F on the mountain). This spot is in the Wasatch Range, I find fossil cephalopod molds (first picture) right at the place this picture was taken(second picture).

    After a few hours hunting I decided to do my Croc Hunter impression, that's why the third picture is blurry.

    I fill the molds I find with liquid latex to get a cast of the shell. The nice thing about liquid latex is it has .6% ammonia added as a drying agent, so I can imagine myself working alongside Steve and Kat while they are playing with a big squid.

    :ammonite:
     

    Attached Files:

  2. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    As Steve Irwin would say, "Crikey mate! Ripper!" Kevin, you are the 'Ammonite Hunter'.

    That rattlesnake is a very impressive. I'm not surprised the picture is a bit blurry; you've got steadier nerves than me! I think I would have cleared off like lightning. How large was it? How close did you get? And that scenery looks beautiful.

    I've managed to find out a little bit of information about Eumorphoceras. This cephalopod is known from both North America and Europe, especially the Texas Barnett formation and examples are known from Yorkshire in the UK. Actually, Europe and North America were very close at this point in time and were actually converging to form part of the later supercontinent Pangea. This goniatite would have inhabited part of the south-west Paleo-Tethys ocean, an area that was diminishing in size.

    This animal existed for about 19 million years from 342-323milion years ago which places it in the early to mid Carboniferous period. It has a very discoid shape with thick whorls and a simple suture. This goniatite, (subfamily: Dimorphoceratacea, family Girtyoceratidea) is usually preserved in aragonite.

    If anyone is interested in how the surface of the earth has changed via continental drift and wondered where land masses were located in relation to each other at any point in time, this is the place to go:

    Paleomap Project

    Fascinating stuff!
     
  3. tonmo

    tonmo Titanites Staff Member Webmaster Moderator

    Joined:
    May 30, 2000
    Messages:
    8,738
    Likes Received:
    516
    Location:
    Pennsylvania
    :lol:

    Right on, that snake looks ready to pounce!

    Phil, that link is great -- it even shows outlines for the US states to show where they were way back when! Hard to tell which is which after a while, since they themselves obviously went through land changes as well.

    Great pictures Architeuthoceras, thanks!
     
  4. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    The little cutey was only about 2 feet (60cm) long. There were three of us surrounding the snake, but, for some reason it kept coming towards me, maybe it could sense something, seeing me stooped over trying to take a picture, walking backwards about to trip over a fallen tree. This is only the third rattler I have run across, and the first time I have had a camera with me to take a picture.
     
  5. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    That is some great information on Eumorphoceras Phil, heres some more:

    Emorphoceras girtyi Elias 1956, is an index fossil for the middle Arnsbergian stage (Early Carboniferous or Late Mississippian). That means as you work your way up thru rock strata, the first appearance of E. girtyi marks the rocks of Middle Arnsbergian age. Higher up in the rock strata another form of ammonoid will take the place of E. girtyi. E. bisulcatum is the next Eumorphoceras in line but is not used as an index fossil for a variety of reasons, so another form is used, in the Western US this would be Cravenoceratoides nititoides which, like E. bisulcatum, is also found in the UK, so the two areas can be correlated and the rocks dated. This process is used to create biozones, so rocks from all over the world can be correlated and dated.
    Rocks of this age in the UK provide a higher resolution for zonation than most other areas, so some are proposing to make those rocks a Global Stratotype, or a place where all other rock strata can be refered to. See Riley, N.J. et. al., 1994, Geochronometry and geochemistry of the European mid-Carboniferous boundary global stratotype proposal, Stonehead Beck, North Yorkshire, UK: Annales de la Societe Geologique de Belgique, v. 116 p. 275-289.
    The following picture file of a correlation chart showing where E. girtyi fits into things comes from Titus, A. L., 2000, Late Mississippian (Arnsbergian Stage E2 Chronozone) Ammonoid Paleontology and Biostratigraphy of the Antler Foreland Basin, California, Nevada, Utah, UGS Bull. 131
    :ammonite:
     

    Attached Files:

  6. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    Wow! Thanks for the detail.

    I had no idea that UK rocks are potentially to be used as a form of baseline in global stratigraphy. Is this because lowland UK has had a very turbulent geological history, with many periods of flooding by shallow seas? Zonation must be very well defined, I suppose.

    Do you by any chance have a similar chart for the Albian in the early Cretaceous? I'd be quite curious to see this as most of the ammonites I find are datable to 100mya and are mostly Hoplites and other members of the Hoplitidae.

    Cheers as ever!
     
  7. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    Got out in the desert yesterday and thought I would post a couple of pics just to show how things went.

    The Ammonoid is Girtyoceras meslerianum, about 327my old. From a concretion that contained a few other ammonoids. The formation it was found in is the Lower Carboniferous (Upper Mississippian) Chainman Shale, it lies just above the Joana Limestone, which is pictured with my truck in the photo below.

    Also caught this pic of a blue bird as I got close to it's nest, never did see the nest, but the bird wouldnt leave me alone. :grin:
     

    Attached Files:

  8. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    Spectacular pictures as always Kevin. That's a very striking bird, any idea what it is?
     
  9. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    The Bird is a Blue Bird, or Mountain Blue Bird, Sialia currucoides.
     
  10. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    Another Girtyoceras, but this one retains some of the shell. And also a bus for scale (the space took up by the pixel used for the dot is probably about 10x the actual size of the fossil :wink:)
     

    Attached Files:

  11. chrono_war01

    chrono_war01 Colossal Squid Supporter

    Joined:
    Oct 7, 2004
    Messages:
    2,580
    Likes Received:
    4
    Tiny-weenie-itsy-bitsy speck of a fossil.
     
  12. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    Ha ha! Great picture there Kevin. That really puts the fossil into perspective!

    Those growth lines are really well preserved; have any conclusions been drawn as to how long goniaties may have lived based on examinations of these features?
     
  13. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    Ive been looking for something Phil, no luck. Studies have been done on Nautilus, and judging from some of the repaired shells of other ammonoids on the ammonoid pathology thread, i would have to think that it didnt take very long for an ammonoid to grow a shell. The baby snails in my garden are full grown by the end of summer. I dont know if ammonoids would have lived as long as nautiloids, or grew shells as fast as snails, but I imagine they would be mature within a year and live for at least two years, some of the larger ones living longer (no proof or evidence, just speculation :wink: ) I'll keep looking.
     
  14. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    Thanks very much for checking for me Kevin. This is just a thought but perhaps if ammonoids generally lived nearer the surface in warmer waters with more sunlight than the deep water Nautilus, perhaps their metabolism worked at a faster rate? Perhaps then their growth rate would be faster and average lifespan would be shorter than Nautilus? Perhaps also the early orthocone nautiloids grew much quicker than Nautilus as they also tended to live in shallower water and inhabited a greater variety of habitats in varied forms.

    I'm sure I read once that ammonoid lifespan has been estimated at anywhee between 4-36 years but I can't find the reference right now. I will report back if I can find it.

    Thanks as ever!
     
  15. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    RIGHT UNDER MY NOSE :oops:

    Bucher, H., J. Guex, N. H. Landman, and S. M. Klofak. 1996. Mode and rate of growth in ammonoids. in Landman, N. H., K. Tanabe, and R. A Davis (eds.), Ammonoid Paleobiology, Plenum Press, New York, pp. 408-463.

    A summary

    Time to reach maturity (from several studies)

    Periodicity of ornamentation
    1-20 years avg. 5
    Seasonality (septal spacing)
    1-7 years
    Size classes
    5-6 years
    Epizoans
    1-7.5 years

    Water Depth

    Shallow @ 5 years
    Deep @ 10-15 years

    Length of life after maturity

    Shallow water forms: possibly semelparous died after reaching maturity and mating
    Deep water forms: iteroparous possibly mated several times and lived several years after.
     
  16. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    It finally cooled off enough I could get out and look for some fossils. Found this Forresteria alluaudi in a large concretion. The first pic shows it as found in the concretion, the phragmocone was filled with calcite that had started to crumble so I had to soak it with super-glue. The second pic shows the fossil after preparation. You can see the last chamber and the last suture. The third pic is just a view showing the side that was exposed.
     

    Attached Files:

  17. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    Some other fossils from the same concretion. Alot of Baculites mariasensis in the first pic. A bivalve (Inoceramus) in the second. And a view showing the concretion atop the teepee butte that formed around it.
     

    Attached Files:

  18. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    Very nice prep job Kevin.

    Just how old is this ammonoid?
     
  19. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    Forresteria alluaudi is an index fossil for the Middle Coniacian (Late Cretaceous) F. alluaudi Zone, aka Scaphites preventricosus Zone, about 88.5mya. In Europe it may be refered to the Peroniceras tridorsatum Zone.
    This is another one of those "Polymorphic" forms having about 10 different genera, sub-genera and species as synonyms. The fossil shown was first described as Barroisiceras (Forresteria) forresteri, it is the more robust and strongly ornamented form, Barroisiceras (Alstadnites) sevierense was described as a medial form, and Barroisiceras (Harleites) castellense was descibed as the compressed, feebly ornamented form. It keeps me wondering why the Cardiocerids and Hoplitids are not lumped together into a single taxon, are there just more specimens to study or more studiers to the specimens, are the lumpers and splitters lumping and splitting 8-)
     
  20. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,391
    Likes Received:
    94
    Location:
    somewhere under the desert sky
    Mass Mortality Molds

    Collignoniceras woollgari regulare, Turonian, Late Cretaceous. At the bottom of scour troughs filled with silt.
     

    Attached Files:

Share This Page