sjaak Posted January 29, 2012 Share Posted January 29, 2012 (edited) Hello, I found this one some time ago. It's a piece of woolly mammoth tusk from the northsea, Netherlands, late pleistocene Only recently I noticed these marks: running along the fractured edge to the inside of the ivory. There is sediment on the edge, so the fracture seems ancient. There appears to be some sediment in the marks, so I think the marks are ancient too. (not completely sure though). I wonder if anyone has an idea what or who made these. Sometimes modern birds pick on bones or ivory on the beach for calcium. I do not think these are bird marks, but maybe I am wrong. Also, I wonder if it makes sense that a predator like hyena gnaws on a piece of tusk... Regards, Niels Edited January 29, 2012 by sjaak Link to comment Share on other sites More sharing options...
Bill Posted January 29, 2012 Share Posted January 29, 2012 Certainly looks gnawed, the grooves on each surface seem to line-up. Possibly ancient Celtic markings though. KOF, Bill. Welcome to the forum, all new members www.ukfossils check it out. Link to comment Share on other sites More sharing options...
Rockwood Posted January 29, 2012 Share Posted January 29, 2012 I would expect predators to get enough calcium in their diet. Something like a rodent seems more likely to me. Link to comment Share on other sites More sharing options...
sjaak Posted January 30, 2012 Author Share Posted January 30, 2012 Thanks for your reactions. I forgot to mention that the piece is about 20 cm; the marks are rather wide, about 3 mm. Link to comment Share on other sites More sharing options...
Plax Posted January 30, 2012 Share Posted January 30, 2012 Scallopers get this kind of pleistocene material off New jersey USA. Any chance some kind of scallop fishing equipment caused this? Some of the marks look fresh. Link to comment Share on other sites More sharing options...
sjaak Posted January 30, 2012 Author Share Posted January 30, 2012 Scallopers get this kind of pleistocene material off New jersey USA. Any chance some kind of scallop fishing equipment caused this? Some of the marks look fresh. This could very well be, since the sand was dredged from the bottom of the sea and hosed upon the beach. I doubt, however, if this is the case because on some places I notice sediment in the marks, only the marks on the fractured edge look fresh, the marks seem to line up and look too regular for damage caused by the hosing. Normally the dredging and hosing equipment just shreds everything into pieces. But maybe I am only seeing what I want...(I think you all know what I mean) Link to comment Share on other sites More sharing options...
Jesse Posted February 2, 2012 Share Posted February 2, 2012 Can you describe the context of the fossil discovery? Was it found in gravels, or river deposit? Found on the surface or under water? Exposed or excavated? What I am seeing is the "marks" appear to have been left before preservation based on what appears to be sediment cemented inside the marks. A bit more information could clear this up and I have an idea what caused them but would like to know depositional environment before I speculate... Cool find and good eye! Link to comment Share on other sites More sharing options...
sjaak Posted February 2, 2012 Author Share Posted February 2, 2012 Can you describe the context of the fossil discovery? Was it found in gravels, or river deposit? Found on the surface or under water? Exposed or excavated? What I am seeing is the "marks" appear to have been left before preservation based on what appears to be sediment cemented inside the marks. A bit more information could clear this up and I have an idea what caused them but would like to know depositional environment before I speculate... Cool find and good eye! Thanks! It was found on the beach in sand that was dredged up by ships from the north sea bottom (Eurogeul?) and then hosed up on the beach. This means that everything you find on the beach is fragmented and mixed up: from great white shark teeth, to mammoth, to WOII bullets and recent coins. As this is a mammoth tusk, it dates from the late Pleistocene (what we call Weichselien). The sediment found on the tusk and other mammoth bones indicates a river deposit. This typical sediment exists of rather rough sand and sometimes shells and wood. After I picked it up, it went unnoticed in a drawer for some years, untill I moved places and rediscovered it. Link to comment Share on other sites More sharing options...
Jesse Posted February 3, 2012 Share Posted February 3, 2012 Alright, without being able to actually hand inspect the specimen all that follows is just a couple of best guesses. My first thought is some type of burrowing insect. The marks look very similar to some burrows left in petrified wood that I have been looking at. The rounded appearance and the rounded "bottom" of a couple of the marks definitely look like burrows of some kind, but I cannot find anything that burrows in ivory. My second thought is this is some kind of erosional marking left from being tumbled in a river system prior to final deposition. This doesn't seem likely though since the marks are not consistent across the surface. I can't imagine any predators or scavengers eating ivory so this seems unlikely. If there is a natural history museum in your area I would recommend taking it there for further evaluation. If it is burrows of some sort, the offending critter would have left "tool" marks that can be identified under magnification. Link to comment Share on other sites More sharing options...
sjaak Posted February 3, 2012 Author Share Posted February 3, 2012 Thanks, Jesse. Never thought about a burrowing insect. Makes sense. I will contact an expert for a further look. Link to comment Share on other sites More sharing options...
mikeymig Posted February 3, 2012 Share Posted February 3, 2012 It was in the ocean for a very long time they could have been made by something like a ship boring mollusc (shipworms). maybe Many times I've wondered how much there is to know. led zeppelin Link to comment Share on other sites More sharing options...
sjaak Posted February 3, 2012 Author Share Posted February 3, 2012 It was in the ocean for a very long time they could have been made by something like a ship boring mollusc (shipworms). maybe I doubt it for several reasons: (i) it was very probably not long at the ocean floor but buried deep underneath in sand (ii) I've seen boring mollusc marks in ivory which look like tiny punch marks (iii) the presence of sediment inside the marks. Ancient boring activity seems plausible to me. Link to comment Share on other sites More sharing options...
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