Marl, a lime rich mud once popular for fertilizer, is found in large amounts in Clayton, New Jersey but though it was mined in the past today it is the fossils preserved in the mud that are of more interest and which were originally discovered quite by accident.
Drexel University are just one Paleontology department who have dug for fossils here and there have been some remarkable, but very delicate finds. Finding fossils, excavating them, transporting them and then displaying them or using them for study and education, has always been a problem and many fossils have never made it back as far as the museums and universities where they can be conserved.
Most the fossils you will see in museums are in fact plaster casts of delicate fossils unsuitable for public display, but they aren’t perfect, to make a plaster cast involves contact with the fossil which can damage it and even then accuracy isn’t always perfect.
Drexel university though are using modern techniques to minimize the risk to fossils and make more accurate models by using 3D scanners and 3D printing: it is even possible for them to scan a fossil immediately after excavation on site so if damage does occur when trying to move the fossil a 3D CAD file exists and can be remade using 3D printing.
3D printing technology is now such that a model can be hugely accurate and so 3D printed fossils are likely to replace many plaster cast pieces in museums in future For uses such as study and education 3D printed models are much tougher than the plaster casts, plus once you have scanned a fossil 3D printing can make as many copies and you like.
What is even more exciting though is actually what 3D scanning and 3D printing allow in the middle stage when the fossil is held as a CAD file on a computer: Drexel University will actually take the model in CAD software and fill in the gaps on a fossil plus can move around different sections on screen to play with how they should fit together.
Filling in gaps is important and something paleontologists have always tried to do, sometimes with relatively crude models based on what parts they do have. As an example a dinosaur’s fossilized skeleton may have parts such as sections of spine, with a CAD file the existing sections can be resized and changed in other ways to make a close replica of missing parts. The fact that a skeleton is symmetrical also means that parts can be switched round in software to fill in the opposite side.
The other thing that having 3D scanned parts for dinosaurs and other prehistoric creatures allows is that a paleontologist can use software to play around with the dinosaur and use modeling to come up with a much more accurate idea of how it would have looked and moved. It is possible for example to put together parts of a dinosaur fossil into a full skeleton and then build up muscle and flesh accurately, in the past this would have had to have been done using artists’ impressions that were often inaccurate. The Hadrosaurus was originally displayed in 1868 as standing upright a 2012 casting now has the same dinosaur based on the same fossils leaning forward with its front legs only just above the ground, almost certainly as it would have stood and achieved thanks to these modern techniques.