drbush Posted December 17, 2017 Share Posted December 17, 2017 Hi friends , a new fossil i needs yr help , I was yesterday in my favort fossil hunting site and i found this large ? gastropod or ammonite , it is 9 inch wide and 6 high what could it be Link to comment Share on other sites More sharing options...
Ludwigia Posted December 17, 2017 Share Posted December 17, 2017 I'd guess gastropod as well, but I'd need photos with higher resolution to say for sure. 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
izak_ Posted December 17, 2017 Share Posted December 17, 2017 I agree with Ludwigia Link to comment Share on other sites More sharing options...
RJB Posted December 17, 2017 Share Posted December 17, 2017 Thats one big gastropod! RB Link to comment Share on other sites More sharing options...
FossilDAWG Posted December 17, 2017 Share Posted December 17, 2017 Where is this from? To me it resembles the Ordovician gastropod Maclurites. Don Link to comment Share on other sites More sharing options...
drbush Posted December 19, 2017 Author Share Posted December 19, 2017 may this help Link to comment Share on other sites More sharing options...
drbush Posted December 19, 2017 Author Share Posted December 19, 2017 the area is early Jurassic of Saudi Arabia Link to comment Share on other sites More sharing options...
Ludwigia Posted December 19, 2017 Share Posted December 19, 2017 Thanks for more photos and approximate stratigraphy. Unfortunately the preservation is so that I can't make out any inner structure, like septal walls or the like. I would lean toward saying that it's a gastropod, although I've never seen anything that large from the Jurassic. The spiral is however very flat, so it could just as well be a weathered down cross section of an ammonite. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
abyssunder Posted December 19, 2017 Share Posted December 19, 2017 The planispiral and polygonal look of the specimens make me think they could be gastropods, maybe close to Discohelix (Pentagonodiscus), although they are very large. excerpt from here " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Ludwigia Posted December 19, 2017 Share Posted December 19, 2017 This is much too large to be a Discohelix. The problem is, I can't for the life of me think of a gastropod of that size and form in the early Jurassic. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
marguy Posted December 19, 2017 Share Posted December 19, 2017 I discovered the subject, the picture made me think of a Caprina cast, but if the Jurassic age is correct, it's not a good idea... Link to comment Share on other sites More sharing options...
abyssunder Posted December 19, 2017 Share Posted December 19, 2017 How could we know it is or not from the Early Jurassic? First of all we have to know the geological age of the sediments where the location of the find is, then the name of the formation. picture from here " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Ludwigia Posted December 19, 2017 Share Posted December 19, 2017 1 hour ago, abyssunder said: How could we know it is or not from the Early Jurassic? First of all we have to know the geological age of the sediments where the location of the find is, then the name of the formation. 16 hours ago, drbush said: the area is early Jurassic of Saudi Arabia I'm just going by what the man said. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
KimTexan Posted December 20, 2017 Share Posted December 20, 2017 Maybe @Tidgy's Dad would know something since he lives closer to the region. Although I don’t recall how familiar he is with Saudi Arabian geology or fossils. I personally have never seen a gastropod that size in that form. I recall seeing some large gastropods from Israel, but they were of a very different sort, not ones that resembled ammonite shapes. They were more like snails. 1 Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted December 20, 2017 Share Posted December 20, 2017 8 hours ago, KimTexan said: Maybe @Tidgy's Dad would know something since he lives closer to the region. Although I don’t recall how familiar he is with Saudi Arabian geology or fossils. I personally have never seen a gastropod that size in that form. I recall seeing some large gastropods from Israel, but they were of a very different sort, not ones that resembled ammonite shapes. They were more like snails. Thanks for thinking of me, Kim Though I am more than 7,000 kms away, I did live and work in Saudi for a year. Great place, but I never went fossil collecting I'm ashamed to say. I saw this thread and quickly hid because I have absolutely no idea. It looks like a gastropod but is too big for this period of time compared to any gastropod I've ever seen from the age. I would guess at a weathered, cracked ammonite, but I have no reason for saying so other than guesswork. Sorry. Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
KimTexan Posted December 20, 2017 Share Posted December 20, 2017 24 minutes ago, Tidgy's Dad said: Thanks for thinking of me, Kim Though I am more than 7,000 kms away, I did live and work in Saudi for a year. Great place, but I never went fossil collecting I'm ashamed to say. I saw this thread and quickly hid because I have absolutely no idea. It looks like a gastropod but is too big for this period of time compared to any gastropod I've ever seen from the age. I would guess at a weathered, cracked ammonite, but I have no reason for saying so other than guesswork. Sorry. Oops, sorry about that. No shame in not knowing. I know you’re not close, but merely closer than many of us in North America. Not going fossil hunting isn’t as bad as me many years ago living in Florida for a year and not going to the beach. I was doing my clinical rotations 60 hours a week, studying every waking hour and working 24 hours every weekend. I had no life other than work and my training. I was so sleep deprived! A few years after I went through the program educators determined it was too much to learn in a year and it is now a 2 year program. 2 Link to comment Share on other sites More sharing options...
abyssunder Posted December 20, 2017 Share Posted December 20, 2017 Maybe the O.P. could give an answer how he came to this conclusion, then it will be easier to exclude some of the possibilities, I think. " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
drbush Posted December 21, 2017 Author Share Posted December 21, 2017 thank you all for the wealth of information , the fossil was found in an area of ohruma formation , Bathonian on top of a small mountain (120 ft) ,on a lower side i found a nautilus. I hope the fig helps . ? could be a withered cephalopod ?? Link to comment Share on other sites More sharing options...
abyssunder Posted December 21, 2017 Share Posted December 21, 2017 The Ohruma formation is Bathonian in age, so it is Middle Jurassic not Lower Jurassic. This rule out any rudists. " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
Guguita2104 Posted December 21, 2017 Share Posted December 21, 2017 This is an odd creature for the Jurassic, indeed...I would have thought that this was a Cretaceous nautiloid or gastropod . I don't know if this helps...At least I hope so. "The age of the Dhruma Formation is based primarily on ammonites and nautiloids but supplemented by micropalaeontological and palynological evidence" "Dhruma lies unconformably on the Early Jurassic (Middle to Late Toarcian) Marrat Formation and is unconformably overlain by the Middle Jurassic (Middle to Late Callovian) Tuwaiq Formation. An allostratigraphic, sequence-based reinterpretation of the originally defined Dhruma now assigns the Atash and Hisyan Members, previously of the uppermost Dhruma Formation, to the overlying Tuwaiq Mountain Formation." Here it's the link:http://www.searchanddiscovery.com/abstracts/html/2010/geo_bahrain/abstracts/Hughes4.html Regards, Link to comment Share on other sites More sharing options...
Ludwigia Posted December 21, 2017 Share Posted December 21, 2017 I'm more and more convinced that this is rather a partial cephalopod than a gastropod. It seems to have lost a lot of the top half, as if erosion has sectioned it off. Unfortunately, the specimen is so damaged and weathered that indicators like rib sculpture or sutures cannot be seen, so I can't even decide if it's an ammonite or a nautilus, let alone guess a genus. How does the other side look? Are any indicators to be seen there or is it just as eroded? A precise stratigraphical position would also help, if possible, since my research has shown that this formation ranges from the Bajocian through the Bathonian up into the Callovian. Link 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
abyssunder Posted December 22, 2017 Share Posted December 22, 2017 To be honest, I never seen such a big, flat Jurassic (or younger) gastropod to be comparable to the specimen in question, so I think gastropod could be ruled out. Also, here is a more recent document related to the Dhruma Formation and its diagenetic alterations: Abdelbaset S. El-Sorogy et al. 2017. Microfacies and diagenesis of the Middle Jurassic Dhruma carbonates, southwest Riyadh, Saudi Arabia. Journal of African Earth Sciences 130:125-133 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
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