Carmel Church microfossils

VMNH has an excellent scanning electron microscope installed in the lab next door to my office. Jason Lunze, our SEM technician, is working on testing some aspects of the SEM software so I gave him some samples of Carmel Church sediment for test imaging. The Carmel Church units are known to have large numbers of diatoms, so we figured there would be plenty to see. (There are also going to be some folks working on Carmel Church diatoms this summer, so it was also a proof-of-concept exercise for that project).

In our tiny (a few square millimeters) sample we haven’t yet found any complete diatoms, but it only took Jason about 30 seconds to start finding fragments like the one at the top of the page. Below is another fragment (I think this one is magnified 6000 times):

In addition, we found several pollen grains:

It’s possible that these grains are modern contamination, but I think there’s a good chance they are fossil given the way they’re embedded in the sediment grains. It’s not surprising that the Calvert Formation at Carmel Church would have pollen; after all, fossil wood is about as common there as whale bones. But this is the first time we have any direct evidence of possible pollen grains.

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4 Responses to Carmel Church microfossils

  1. Brian Beatty says:

    Would it be possible to retrieve some uncontaminated portions of the sediment from inside a jacket? We could characterize the grain size and composition of the sediment (calcareous vs siliclastic). It would also be excellent to look for what sorts of phytoliths were present in the locality. Then, perhaps we could look at dental microwear of the terrestrial ungulates in a slightly more controlled way. It would be ideal if their teeth had calculus on them that could be removed and phytoliths extracted, but that would require a bit of luck.
    Still, something that I’ve been wanting to do with more controlled modern settings, but it would be nice to start with some fossil localities too.

  2. Alton Dooley says:

    Getting uncontaminated samples should be possible. This was a bit of sediment just scraped off a bone with no processing, just to see if we could get good images.

    At Carmel Church our numbers of terrestrial mammal teeth are very small, so we would need to have a LOT of luck to get phytoliths (especially considering that they had already washed out to sea before burial). But in terrestrial environments (and certainly modern ones) that should be quite possible.

    Our SEM also has an EDAX, for doing composition analysis, so there’s even more potential for these types of detailed studies.

  3. Keith Degnan says:

    The last picture is not pollen, but rather a dinoflagellate cyst. I’m not familiar with Cenozoic species, but it looks like it’s in pretty good shape.

  4. Alton Dooley says:

    And so my limited knowledge of microfossils is revealed! Thanks, Keith!

    Dinoflagellates are also known from the Calvert, and so finding them isn’t a great shock, but we’ve never seen them at Carmel Church (of course, this is the first sample we’ve ever put in the SEM).

    There’s a photo of a somewhat similar dinoflagellate cyst at this website:

    (scroll down about 3/4 of the way to the bottom).

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