Trace Fossils (September 10 & 12)

Let’s start with the Wikipedia page for trace fossils. Note that trace fossils are sometimes called ichnofossils, and the study of them is ichnology. Wooster has an excellent collection of hardgrounds, especially from the calcite seas of the Ordovician and Jurassic, on which we will see many borings and other examples of bioerosion. We also have a good soft-sediment trace fossil set, much of it inherited from the late Professor Richard G. Osgood, Jr.

You will see that the large majority of our trace fossils are marine because, naturally, most traces come from marine sedimentary rocks. I wish we had more dinosaur tracks, but they are best enjoyed and studied when they are still in place.

Our summative project for trace fossils will be the descriptions, distribution, and analysis of ichnofacies. Done correctly, an ichnofacies study can reveal much about paleoecosystems.

Dr. Patricia Kelley visits class on Thursday, September 12; she will speak on drilling predation. She also gives a Geology Club talk at 11:00 a.m. in Scovel 205 (required).

Lab report #1 due in Dropbox by noon on Tuesday.

Geology in the News —

A cool trace and body fossil combination found in the Ediacaran of China. This rare kind of trace is called a mortichnium. (You can figure out those roots.) The specimen has started an interesting conversation about evidence for the earliest animal motion. Here is the original article in Nature.

Why did coyotes survive from the Pleistocene but not saber-toothed cats? Apparently coyotes, which are notorious omnivores, adapted better to changing climates and food resources.