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Thomas Farm Volunteer Dig, Spring 2014


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This weekend my wife and I are heading up to volunteer at the Thomas Farm fossil dig in Gilchrist County that is being run by the Division of Vertebrate Paleontology at the Florida Museum of Natural History in Gainesville. I discovered this opportunity when visiting their website to renew my Florida fossil permit. True, you don't get to keep what you might find but you do get to see fossils in situ in the sandy clay matrix rather than all tumbled and jumbled (and blackened) in a sifting screen while standing waist deep in the Peace River.

I checked the website and it seems (from their last update) that there may still be some volunteer slots open for some of the dates. I have no idea how current their website is being maintained but I'm assuming there are still opportunities here for this year. If you are interested an application form and contact email for Richard Hulbert (who is organizing and leading this dig) can be found here:

http://www.flmnh.ufl.edu/vertpaleo/Spring_2014.htm

As the first of this year's sessions is already underway (started yesterday) I'm assuming Dr. Hulbert will only be having a chance to catch-up on emails in the evenings. If you think it would be fun to work with scientists (and other volunteers) to dig at one of the most fossil rich sites in Florida, there may still be opportunities for this year. Visit the link above and contact Dr. Hulbert to see if you can still be part of this year's efforts.

Videos and photos from a previous dig are also available on the FLMNH website via this link:

http://www.flmnh.ufl.edu/thomasfarm/videos/

http://www.flmnh.ufl.edu/thomasfarm/images/

I'll post some photos from our trip after I get back next week.

Cheers.

-Ken

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rare opp to get hands dirty at a famous site...i'd jump on it!

Grüße,

Daniel A. Wöhr aus Südtexas

"To the motivated go the spoils."

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I'll be there April 3-6 next week. I participated in the Thomas Farm dig and the Millenium Park (St. Petersburg, FL) dig last year and enjoyed both. A great opportunity to learn how the professionals manage a dig site and learn from the pros. The Thomas Farm site has lots of bone from many species (Miocene age) that I don't have opportunity to see in AL where I do most of my collecting, so a good learning experience. The digging is very meticulous -- one is assigned a meter square area and digs with a screwdriver at 10 cm depth intervals; bagging and labeling all fossil material and the matrix. The matrix is screen-washed later for the very small specimens. Most of the bone is very fragile, so progress is slow. Dr. Hulbert is extremely knowlegeable about the fossils occurring at the site and is a pleasure to dig with. Looking forward to meeting you, Ken.

George

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I'll miss you by a few days as my wife and I are only going up for this weekend. I'm planning on taking a camera and posting photos of anything interesting that surfaces while we are working at the site. I encourage you to do the same and add to this topic.

Good luck and hope something interesting turns up in your square meter.

Cheers.

-Ken

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Oops, another misread on my part. Hope you have good luck this weekend and leave a few for the second crew. Attached are a couple of pics from last years' dig which may whet your appetite. A partial rhino femur which I was fortunate enough to excavate and jacket. Note all of the fractures on the bone. Turns out that Richard H. had found the missing piece on the previous dig. Take care.

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George

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Consider my appetite well whet. I'm really looking forward to this. Always wanted to do a dinosaur dig out west (still on the fossil bucket list). This is only 5 hours away and so I jumped at the opportunity.

-Ken

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Anybody living in the majority of the Florida peninsula will know that this weekend has been a rainy mess. A system formed over the Gulf of Mexico and blew in from the west blanketing a good portion of Florida in heavy clouds and soaking rain. My wife and I drove up from South Florida Friday afternoon and landed in Gainesville by early evening. The small hotel we check into had a section of rooms that were only one story with a thin roof so we could hear the storm raging all night and pounding the roof with waves of rain.I enjoy great examples of Nature's fury but unfortunately the sodden conditions were not conducive for paleontological excavations.

We found our way to the Thomas Farm dig site--at the end of a long muddy road. We met-up with Dr. Richard Hulbert and his associate Kristen MacKenzie who were looking skyward and listening to the distant rumbling of thunder. Soon after our arrival the skies opened up and released another soaking downpour. A quick consultation with the local radar maps on a smart phone and the decision was made to call the dig for the day (in fact for the entire weekend). Sloppy conditions don't make for good science and it was decided best to let things dry out before continuing the excavations at the site.

We headed back home to South Florida after a brief visit to the Florida Museum of Natural History. We had rainy conditions the entire drive home. Dr. Hulbert said that they'd bring some extra equipment along if we wanted to try for a (literal) rain date next weekend. We'll probably make the return trip so we may yet have a chance to meet-up yet, George.

-Ken

Photos below of Dr. Hulbert and Kristen MacKenzie watching as the skies opened up and a quick view of the tarped site during a brief respite between downpours.

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As a side note, anybody in Florida (or visiting) who is interested in the fossils that can be found in the state should really visit the Florida Museum of Natural History. It's free and the fossil exhibits can be perused in a couple of hours. Those who are fans of megalodon teeth (and other larger shark teeth) will love the shark jaw display. The reconstructed mammoth and mastodon skeletons give you an appreciation of the bulk of these beasts. Then there is the main display room containing mounted skeletons of several interesting species like bear-dogs, three-roed horses, rhinos, saber cats, horses, llamas, sloths, and giant armadillos. It's really interesting to see complete skeletons of animals we find only in isolated fragment form.

-Ken

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Thanks for the update and photos, Ken. Sorry about the rain-out. Hopefully it will be drier this coming week.

George

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I'm really surprised that the rains we drove through for 5 hours on our way back from Gainesville seemed to have missed the Peace River watershed. I just checked the river gauges and they haven't registered much of a bump at all. From my point of view (behind a steering wheel) it was a wipers on top speed, slowing to a crawl in the interstate kind of a deluge. My weather radar page shows another area of clouds out over the Gulf of Mexico but I'm hoping that amounts to little and that the sun can shine though and dry out the dig site by next weekend.

Here's hoping for an update on the old adage, "Second time's a charm!"

-Ken

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Made it back up to Gainesville (for the second weekend in a row) and the 1,500 total miles for the double round trip finally paid off. The weather was overcast but dry at the Thomas Farm dig site over the weekend and we finally got to dig on this important fossil site.

We were joined by a group of other experienced volunteers at the dig (we were the only newbies) but with a little instruction we got into working our 1x1 meter square searching for fossils. The site is divided up into these square meters by a grid of nails (with orange flagging tape) that mark the corners of each square. Each square is excavated 10 cm of depth at a time and all of the sand/clay matrix removed is placed into plastic sandbag sacks (complete with a label indicating the grid square, elevation, and date that it was removed) before being securely closed with a large cable tie. The matrix will be micro sifted at a later date looking for micro fossils to complete the assay of the fossil assemblage for that square at the indicated depth. The depth of each square is measured by the use of a folding ruler and a string tied off at a datum point. A small bubble level is attached to the string and the free end of the string is held to the outfolded ruler which is held vertically resting on a point in the grid square. The string is raised and lowered till the level shows the string is horizontal at which point the vertical distance down to the surface of the grid square can be measured off the folding ruler. Using this ingeniously simple system of fixed grids and vertical elevation measurements the site is subdivided into a 3D system of 1m x 1m x 10cm "slabs". The locations of the fossils within each of these cells is not recorded only the grid cell and depth range.

My wife Tammy and I were assigned a grid cell 10N x 5E and were first instructed to complete the leveling to the 160 cm point (1.6 m below their datum point). The person working this grid square the previous day had not been able to complete the leveling to this point so we finished that task. All of the matrix was loaded into the plastic sandbags as we worked with screwdrivers and dental pics to probe through the sand and clay layers. A carpenter's level was available to help ensure the vertical level but usually we were excavating down to the level of an adjoining square so it was not too difficult to manage the amount of material that needed to be removed.

Our square was being stubbornly unproductive yielding only a single toe bone (metapodial?) from a small 3-toed horse species, likely Parahippus leonensis. One of the other squares when we got there had three jackets from the night before containing a camelid scapula, a rhino bone (leg I think), and a horse skull--a much more productive square at that level.

-Ken

The images below show the gridded layout of the site at the start of the morning with the overly productive square containing three jackets from the previous day.

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Here I am shown working studiously at leveling our square bit by bit with high-tech paleontological equipment (a flat blade screwdriver). The dig supervisor Dr. Richard Hulbert can be seen in the background (in the blue hat prepping a fossil aggregation for jacketing). Also shown, my wife modeling her first find--a toe bone from a 3-toed horse, Parahippus leonensis, the most commonly found species at the Thomas Farm dig site. Also commonly found there are bones from the smaller Archaeohippus blackbergi.

-Ken

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It was interesting to watch Kristen jacket delicate specimens for later preparation. Kristen MacKenzie, the Assistant Collections Manager at FLMNH, was working with Dr. Hulbert to assist the volunteer diggers at the site and she did most of the jacketing work. If an important fossil is unearthed a pedestal is formed around the bone(s) by digging a trench around the section to be removed. The bones are spritzed with some water with the help of a whisk broom and a bucket of water. After which rolled-up wads of PT (Paleo Tissue)--which look remarkably like the familiar TP (Toilet Paper) and in fact are one and the same--are wetted and placed over the bones so that the plaster jacketing doesn't stick to them. They are also used to build out the top surface to a smooth contour to make the next step easier. Medical grade gauze strips impregnated with quick-setting plaster of Paris are quickly dipped in a bucket of water and applied to the pedestal, wrapping the fossils in a sturdy plaster jacket. After the plaster has set the pedestal is separated from the grid cell with the use of a hammer and small shovel for larger jackets (see 4th photo on post #13 above) or simply by levering off with a small hand trowel for smaller jackets.

-Ken

Here is the a sequence showing how a delicate fossil (a Parahippus leonensis jawbone) is excavated to a pedestal, moistened, padded with PT(TP), and wrapped with plaster gauze to form a sturdy jacket.

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We continued to work our very sparse grid cell with only a few meager finds. My wife did find a lovely little Parahippus molar and I found a right calcaneum (heel bone) from the same species. Below are images of the calcaneum in the matrix and after being removed. It seems that leg bones are pretty dense given their role so they tend to end up as somewhat sturdy fossils. Many of the bones (or fragments) found were so delicate that many turned to dust as they are attempted to be loosened from the surrounding matrix. More common delicate bones are simply "chunked out" and put into small zip top baggies to be reassembled later in the lab. More important bones get the extra special attention of jacketing as described above.

-Ken

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I can't thank you enough for taking the time to photographically record the process! This is very informative, and brings it alive for me :)

"There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant

“Try to learn something about everything and everything about something.” - Thomas Henry Huxley

>Paleontology is an evolving science.

>May your wonders never cease!

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Toward the end of the first day our luck finally turned around. Nearby the calcaneum in a section of our grid that finally started producing some fossils (in a sandy later beneath a thick multicolored, multilaminated layer of clay). I uncovered another solid (not crumbly) bone and as I worked it more delicately with a dental pick it revealed itself as a jawbone (once I spotted teeth poking from one edge). I assumed it was another Parahippus jawbone as several were found this weekend. When I showed it to Dr. Hulbert I was surprised to find that it was not from a herbivore at all but from a small carnivore species--the shape of the teeth once revealed showed that clearly. To a novice like me, a jaw is a jaw--but to the experts it was something special. Dr. Jonathan Bloch, the Associate Curator of Vertebrate Paleontology at FLMNH, who was also out digging with us came over to have a look, and was duly impressed.

It turns out that horse bones make up a large portion of the fossils found at the site but small carnivores like this are much more uncommon (even to the point of being considered rare). This was the jaw of a small badger-like carnivore in the family Mustelidae (commonly called mustelids) and likely from the species Leptarctus ancipidens. I was told later that while they have hundreds of jawbones of horses from the Thomas Farm site, the fossil finds for this species would likely fill a shoebox. I was excited that they were excited.

Our square may not have given up the most fossils this weekend but at least it produced something relatively rare and valuable to the scientists working on the small carnivores of this site. I'm hoping that because of the current interest in this class of fossils that my little find will be prepped from its jacket relatively soon so I can see what it looks like in its entirety.

-Ken

Here are a sequence of images showing my mustelid jawbone being prepped for jacketing. Because it was found so late on the first day it was re-covered with moist sand (to prevent drying and cracking) and some cushioning knee pads when the site was re-tarped overnight. The next morning trenching around the fossil to form a pedestal was my first order of business. The sequence concludes with a group shot of me holding my prize along with Kristen and Richard (Dr. Hulbert) and my wife Tammy.

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I can't thank you enough for taking the time to photographically record the process! This is very informative, and brings it alive for me :)

Thanks. As you can tell from the word count on most of my posts, I tend to be verbose (and a bit of a story teller). It is said that the act of asking me a question tends to be like taking a drink from a fire hose. I also believe that pictures are worth a thousand words and can really help bring color to a story. I enjoy photography and even with a little point-and-shoot I tried to take time away from digging to document the day a little.

I really enjoy reading other people's posts when they are photo rich so I'm trying to return the favor (possibly encouraging others to sign-up for a dig next spring when the FLNHM returns to the Thomas Farm site to see what other treasures it will give up).

Cheers.

-Ken

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Ken, thanks for the photos and the details! Neat stuff and very cool to find a carnivore.

So from what I can see in some of the thomas farm links that site was an early Miocene sink hole that had some associated caves? Does that sound right? Is that contemporaneous in age with some of and (aside from the marine/meg stuff) the same fauna that we could pull from the Peace River? Regards, Chris

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From what I know the Thomas Farm fossil site was a cave system where the roof collapsed to form a sink hole. The site is right down the road from Ginnie Springs and many other spring features in the area--the whole region is a karst wonderland well known to cave divers and spring swimmers. The species assemblage seems to date the site to the early Miocene Epoch (early Hemingfordian--about 18 mya). By using several indicator species found at Thomas Farm which are found at other sites where the site's age can be accurately determined (e.g. radiometric dating) it is possible to assign a reasonable estimate to this site even though no direct dating of the Thomas Farm material was possible. They think that the accumulated layers may only represent a small time slice of possibly just a few thousand years. The important thing about it is that it contains a wide spectrum of animals that were in the area at the time--from frogs to birds to bear-dogs, horses, and gators (but very, very rarely fishes).

I would suspect that the Peace River material that we usually find in our sifters would include this slice of geological time though it spans a much wider swath (up to nearly recent times). The limestone surrounding the sinkhole is of Eocene age and occasionally marine fossils are found in the matrix. In fact the coarse sand layers are in fact carbonate sand (not silica) likely from the cave system surrounding the site. I did find a small single valve of an Eocene bivalve (not yet identified) in the sandy matrix I removed while prepping the carnivore jaw to be jacketed. As the museum is not interested in invertebrate fossils I was allowed to keep this as a keepsake to go along with my photos (and memories--though photos last longer these days).

Hope this helps explain this biodiverse snapshot of Florida at about 18 mya.

Cheers.

-Ken

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Nice job of explaining the processes of finding and extracting fossils at this site, Ken. You nailed it! Attached are a few more photos of fossils from the dig.

Photo 1 is a scapula of a camel (large jacket in one of your previous photos).

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photo 2 is a dog femur (possibly Metatomarctus canavus)

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#3 is that of a dog jaw with no teeth attached.

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#4 is a horse tibia (Archaeohippus blackbergi).

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#5 is a horse rib (probably Parahippus leonensis). Very common at this site.

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#6 is a group of bones including a horse femur, a partial horse pelvis, and part of a canid scapula (upper left corner), and a bear-dog tooth. I don't know what the large bone on top is. Bones were stacked in this corner of my square.

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Enjoy.

George

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You definitely did have a more productive grid square than we did. It was still great seeing all of the bits that turned up in other people's squares. Much like sifting for fossils in the Peace River with a group--you get to see more even if it doesn't end up in your collection. At least we had a cool mustelid jaw to save the day for us.

We also had fun camping out at the site on Saturday night (instead of returning to a hotel in Gainesville). One of the volunteers (John) found that if you hold your flashlight near your temple and look out at the sparse grassy field where we camped that you could see the green eye shine of hundreds of wolf spiders. Like the problem with "red eye" in photographs, the light needed to be very close to your eyes making a narrow reflection angle. If you moved the light a foot away from your head the little green "arachno-LEDs" went out. It was a fun bonding experience for the volunteers who camped out--giving us the creeps just before bedtime...

Cheers.

-Ken

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This is really great documentation of a very cool experience. Thanks for sharing.

"I am glad I shall never be young without wild country to be young in. Of what avail are forty freedoms without a blank spot on the map?"  ~Aldo Leopold (1887-1948) 

 

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I created this thread for just that reason to document the experience so that others may experience it vicariously through the Forum. For those within driving distance (or true fanatics who would book a flight for the opportunity) I encourage them to consider volunteering for next year's dig (around the same time). The Florida Museum of Natural History website will post the volunteer opportunity on their website (likely this link):

http://www.flmnh.ufl.edu/vertpaleo/field_vols.htm

Put it on your calendar to start checking their website sometime in mid-January, 2015. It's a great opportunity to work on a very special (and scientifically important) fossil site with some very smart people from FLMNH (Dr. Hulbert and others) as well as some really great, like-minded volunteers.

Cheers.

-Ken

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