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Florida Eocene Seagrasses


calhounensis

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I've been doing some research on seagrass from the Florida Eocene. I found the Benzecry paper in the Botanical Journal mentions two species, Thalassia and Enhalus, from the Avon Park Fm. I haven't gotten access to the full paper yet, but intend to read it when I do. Has anyone on the forum found specimens that they could share with me on this post? I would appreciate it, I'm interested in the seagrass as the primary food source for the Eocene sirenians from the same formation, as well as the Ocala Limestone. Also if anyone has seagrass specimens from the Ocala Limestone, I would be interested in seeing examples from that formation as well.

Daniel

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Opened my copy of the Geology of Florida and did some digging. I found quite a bit of information on the Avon Park Fm., as well as some of the plant material here. I would still welcome any insight or specimens out there. Does anyone know if there is active mining that is exposing this formation? The formation itself sounds fascinating and I just learned that it is the oldest exposed material in Florida.

Edited by calhounensis
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Hi Daniel

In March, the Southeast Geological Society field trip was to several quarries in Citrus County, Florida. Two mined the Upper Ocala, however the last stop was to the Red Level Mine which quarries the Avon Park Formation. Mostly mollusks and a few echinoids but I did pick up a chunk of the limestone which had carbonaceous plant pieces that can't be identified to genus. I will look to see if I can find it in my garage as I have yet to go through that material.

Mike

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"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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Thank you Mike,

I've been meaning to join SEGS for some time, I guess I missed my chance at Avon Park for now. Maybe Roger will lead a trip with FPS in the future. The reading I was doing showed that Avon Park was a nursery of sorts for juvenile mollusks, echinoderms and epibionts. Protosirens and Cheloniids were feeding on the seagrass, creating quite a diverse Eocene ecosystem.

Daniel

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I have found what appears to be seagrasses in limestone from a quarry in Marianna, FL. I will have to go digging through my boxes of outtakes to find them. I also found a Quercus leaf once.

---Prem

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Thanks for looking Prem.

I would like to see them if you can dig them up. I'm assuming you're talking about Brooks Quarry? In all the reading I have been doing, I have not come across any preserved plants from the formations there;Ocala, Bumpnose, and Marianna Limestones. If it is that could be a rare find, plant fossils are extremely rare in Florida's fossil record. I'll do some more reading on the matter and see.

Daniel

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I remember seeing fossil sea grasses on limestone from Marianna in the displays in the Carraway building at FSU many years ago, and possibly at the University of Florida Museum of Natural History, if I recall correctly.

---Prem

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Although seagrasses are rarely preserved, I've heard that they can baffle and stabilize sediments. I wonder if their presence could be indirectly detected through specific textural characteristics of the rock even if there is no physical trace of the plants. Also, certain epibionts (mentioned above) remaining in the sediment could also potentially be signs (Just guessing on all of this. I have no idea if it is actually possible. :) ).

Context is critical.

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Through reading, seagrass presence can usually be inferred by many organisms. Sirenia and Cheloniids both relied heavily on seagrasses. Epiphytes and Epizoans both point towards an ecosystem with seagrasses as well. Seasonal macroalgae can even give clues to the burial season. Knowing the environmental contributions of each organism can show that many soft-bodied organisms (Hydrozoa, Parazoa) had been there, although they did not preserve. It's certainly possible that texture could be seen under magnification. The silicone peels used for moldic inverts might even show this texture. (just a guess) Animal-Plant Relationships and Paleobiogeography of an Eocene Seagrass Community from Florida is a good read for this topic. The authors (Ivany, Portell, and Jones) did an excellent job identifying the taxa from two Avon Park localities by looking at similar ecosystems today. Florida Bay seems to be a remarkably close environment to that of the Eocene seagrass layer in Avon Park.

Edited by calhounensis
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Daniel

Would you happen to have a pdf of the Ivany et. al. paper that you reference above that you can pm me?

Thanks

Mike

"A problem solved is a problem caused"--Karl Pilkington

"I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain

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  • 1 year later...

Thank you for posting the link!

Nice to have one of the co-authors aboard.

Welcome to the Forum. :)

Regards,

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Hey Gang, some more info.

Back in February I was at the Tampa Bay Fossil club meeting and one of the members during the show and tell had a slab of sea grass and I took a photo--my poor memory cant provide the location--one of the local club trips...maybe Inglis? I cant find my club bulletin as I was looking to give credit to the member/finder so if you are also a member here...please take credit and offer any details. Thalassites parkavonensis

Wanted to share the picture of the specimen and the reference that was provided. A new hydrocharitacean seagrass from the Eocene of Florida, Benzecry and Brach-Hanes, Botanical Journal of the Linnean Society, 2008, 157, p19-30.

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I also attended the Lee County fossil club's fossil fest back in Dec last year and they had a really neat ton of florida material of all kinds and a great deal of museum material, mostly verts and inverts...I snapped this picture of sea grass with a brittle star...aint the greatest photo but its all I got. Thalassodendron sp.

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Edited by Plantguy
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