Conference Review: Rocky Mountain GSA

The University of Idaho
Site of this year's Rocky Mountain GSA meeting

This week, the Rocky Mountain Section of the Geological Society of America descended from said mountains to the Inland Northwest, hosting their annual meeting in at the University of Idaho in Moscow.  While I hadn't submitted an abstract, the combination of proximity, a freer schedule now that classes are over for the year, a field trip to Clarkia, and a session on lagerstätten was enough to entice me down to the Palouse.  While paleontology did not feature nearly as prominently as it did at the previous GSA sectional meeting I'd attended, there were a few highlights that I wanted to share:

• The primary allure of the conference was the field trip to the Clarkia fossil beds of north-central Idaho.  Having taken my Paleobiology class to one of these sites last semester, I had some familiarity with the Clarkia fossils, but I didn't want to pass up a chance to learn more about them from researchers who had focused on them, notably co-organizers palynologist Bridget Wade  and paleobotanist Bill Rember, both of UI, and Ralph Stearley of Calvin College, who has worked on fossil fish from around the Northwest.  The organizers, my fellow attendees, and the fossils themselves predictably did not disappoint.  My effusive praise of Clarkia deserves a post of its own, so expect one in the near future.  For now, all I'll say is that it ranks right up there with sites such as Ashfall and Messel in terms of the paleobiological story it tells, and it surpasses all other sites I know of in terms of quality of preservation.
• Speaking of Clarkia, there was one presentation relevant to it at the conference, but it focused not on fossils but on several layers of volcanic ash present at various localities in the region.  The research, conducted by Washington State's Cassie Geraghty, found that several of the ash layers were likely produced by a volcanic field in northern Nevada that was active about 15.5 million years ago.  This is significant because it means that the Clarkia biota lived at the peak of the Mid-Miocene Climatic Optimum, the last major period of global warming in Earth's history, making it not only intrinsically interesting from an ecological perspective, but providing a possible glimpse of what might happen to organisms and ecosystems as climate continues to warm going into the future.  Another poster in the same session, by Klarissa Davis, also of WSU, looked into the connection between volcanism and climate in the mid-Miocene, suggesting that the Columbia River Basalts, that still cover much of the Inland Northwest today, may have played a large role in driving climate at the time by releasing greenhouse gases during eruption.
• The only paleontology-focused session was on lagerstätten, and featured several talks by

  

  The sunfish Archoplites
  Clarkia Fossil Beds

  paleontologists from around (and, in a few cases, beyond) the region.  The most interesting from my perspective was given by the University of Montana's Lindsey Mackenzie.  There has been a long-standing tradition of categorizing lagerstätten into "preservation type" groups (e.g, Burgess Shale-type preservation).  Lindsay's work recently has been on analyzing whether or not these groups actually reflect chemical, geological, and geographic reality.  The project is still in its infancy, but it should be very interesting to see how it unfolds, as it will probably have major paleoecological implications.  Other interesting talks in the session included descriptions of the invertebrate faunas of the Raven's Throat and Bear Gulch lagerstätten by Julien Kimmig and Amy Singer, respectively, and of the Miocene fossil fish of Idaho and Oregon by the aforementioned Ralph Stearley.  The most exciting bit of news from the latter talk was that Ralph and his colleagues may have identified a kokanee population of the saber-toothed salmon Oncorhynchus rastrosus; that is, they have evidence that a landlocked population of the usually enormous fish became dwarfed, which would certainly add a new twist to the saga of one of the Northwest's most bizarre extinct animals.