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Re: Exact length of Sue



Thank you, Professor Holtz! Your GEOL 104 syllabus provides more detail and I 
will endeavor to present a more realistic version of the process in the future.


On Apr 21, 2015, at 9:24 PM, tholtz <tholtz@geology.umd.edu> wrote:

> That is rather out-of-date thinking, actually. Most fossil bone is 
> permineralized: the original bony mineral (hydroxylapatite) and even collagen 
> is still present, but the pore space is filled to some degree with minerals 
> from ground water. Some fossil bone is unaltered: nothing added, nothing lost 
> except the greasy organics. Actual honest-to-goodness replacement is very 
> rare for fossil bone, although more common in fossils of some other groups.
> 
> So the real bone is there. But there is other stuff added.
> 
> On 2015-04-21 21:13, Victoria & Jerrold Alpern wrote:
>> Dan,
>> What I meant was that the organic bones that supported the dinosaur in
>> life were replaced underground by minerals that formed an exact cast
>> of the originals. These are precise enough replicas that they carry
>> the information, including isotope signatures, LAGs, etc. that provide
>> the raw material of paleohistology. If I am wrong, or have stated the
>> process incorrectly, please tell me. Many who come to AMNH are
>> interested in dinosaurs but have never considered the process of
>> fossilization.  My only wish is to convey accurate information to AMNH
>> visitors.
>> Thank you!
>> Jerry Alpern
>> On Apr 21, 2015, at 8:51 PM, Dan Chure <danchure@easilink.com> wrote:
>>> I don't think this is quite true: "most fossils are themselves casts of the 
>>> original bones." If it was, there would be no discipline of paleohistology.
>>> Dan
>>> On 4/21/2015 10:37 AM, Victoria & Jerrold Alpern wrote:
>>>> Thanks! I had thought both legs of AMNH 5027 were replicas of CM 9380, 
>>>> which I assume is the holotype we sold to the Carnegie in the 1940s. Now 
>>>> I’m going to have to revise what I tell visitors!  They often assume that 
>>>> what they see are “fakes”, by which they mean copies. They are happy to 
>>>> learn that most of our 4th Floor fossils are genuine, although I always 
>>>> add that most fossils are themselves casts of the original bones.
>>>> Jerry Alpern
> 
> -- 
> Thomas R. Holtz, Jr.
> Email: tholtz@umd.edu   Phone: 301-405-4084
> Geology Office: Geology 4106
> Scholars Office: Centreville 1216
> Senior Lecturer, Vertebrate Paleontology
> Dept. of Geology, University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661
> 
> Faculty Director, Science & Global Change Program, College Park Scholars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
> 
> Mailing Address:        Thomas R. Holtz, Jr.
>                        Department of Geology
>                        Building 237, Room 1117
>                        University of Maryland
>                        College Park, MD 20742 USA