I’m on my way back home from the SE GSA conference, and I finally have a chance to write about the second day of the meeting. Things got very busy at the WSC booth (we sold most of our inventory of casts!), and as a result I missed the entire morning session of talks except for single poster.
That poster was by Nickacia Young and Rowan Lockwood on the effects of cementation on the preservation of fossil shells in Late Miocene deposits on the Virginia Coastal Plain. These deposits, called the Eastover Formation, are extremely rich in fossil shells. They are usually unlithified, meaning that the sediments are soft and can be dug out with a pick and shovel, such as in the image above. But in a few places the Eastover is lithified, meaning that it has fused into solid rock, as with the orange blocks in the image below:
According to Young and Lockwood the number of species of shells (the diversity) in the lithified Eastover is much lower than in unlithified samples. This could have implications in estimating biodiversity in other deposits in which the entire deposit is lithified; if it behaves like the Eastover we may only be seeing a small subset of the species that were originally present.
In the afternoon I pick up a couple of talks in a session on faults and shear zones in the Appalachians. John Hickman discussed deeply buried fault zones beneath Kentucky, and suggested that they form part of a Precambrian rift system associated with the breakup of the supercontinent Rodinia in the Late Proterozoic Eon.
The next talk was presented by Chuck Bailey, on which I was one of four coauthors. This was on the presence of Mesozoic faults in the Hylas Fault Zone at the edge of the Virginia Coastal Plain and their effect on younger Cenozoic sediments. I was involved in this talk because one of the study sites was the Carmel Church Quarry, a marine fossil site that I have been excavating for more than 20 years. During and excavation I led at Carmel Church in 2014 we discovered a boulder field buried in the Miocene sediments along with whales and other marine fossils:
I suspected that structural activity might be responsible for the presence of these boulders, and since Chuck was working on faults in this region I asked him to take a look at the boulder field. Based on work by Chuck and his students it appears that the boulder field was most likely formed by the reactivation of a Triassic fault in the Miocene.
As soon as Chuck’s talk was finished I raced to another lecture hall to catch the end of a session on teaching evolution in the southeast, organized by Patricia Kelley and Christy Visaggi. This was actually an all-day session with 16 talks, and while the booth kept me away from the morning session Brett was able to attend. I had to attend the afternoon session, though, because Brett and I were jointly presenting a talk on teaching activities for getting students used to making hypotheses based on limited data. This included a description of the cast-based teaching kits that Brett and I have been developing based on specimens housed at the Western Science Center, as well as the adaptation of online lessons for courses in historical sciences.
The last talks at SE GSA were Friday afternoon. There were also several post-meeting field trips on Saturday, but with long drives ahead of us Brett and I had to start heading back to Virginia and California, respectively. This was a fun and productive meeting, and I have to say that, having attended conferences in dozens of cities, Chattanooga was one of the nicest conference cities I’ve ever seen.