Archive for the ‘Ranger Doug Roadtrips’ Category

The Great Phytosaur Femur Recovery

Sunday, April 7th, 2019

After my Phytosaur femur assembly (see three blogs back), I could not assemble the proximal and distal heads of this particular bone which demanded a field trip back to the site.

I can’t be too specific where this is, but one can get very lost in country like this.

My paleontology mentor is Indiana Chuck–do you think Hollywood would be interested–and here he studies a jacket of plaster moulded over some bone fragments to preserve their relationship.  Water is precious there and has to be carried in to mix the plaster.

Once the plaster sets, the jacket is flipped over in larger cases a lid is plastered into placer–a full jacket.  We fill in our divots.  While the plaster is setting, I take a 1/4 mile hike around looking for more bone fragments.

I’m now on the next summit–do not go into these hills alone.  I wonder if Forrest Fenn’s treasure lies anywhere near here?

This our treasure–bone fragments and we scramble around looking for that missing Phytosaur femur…..and find what we think is the right piece.  Indiana Chuck is a great teacher–I should have stayed in geology.  My last coursework was in the late 60s and much has changed since then; not the geology itself, but the knowledge base….and computers.

The scenery around us.

The hard debris tumbles downhill in clumps;  here 220 million year old logs

The larger pieces create their own pedestals.   This is a popular hiking trail just below the Desert View Museum at the north end of the park–one of my favorite NPS park buildings (see previous blog).

The second museum is located at the southern end of Petrified Forest National Park–and focuses on paleontology.  Here a CCC diorama–one of the very few left in the NPS system–depicts two Phytosaurs fighting to the death–an actual dual discovered by paleontologist Jim Camp back in the ’30s.  The Phytosaur’s were anything but plant eaters–check out this jaw:

This is both halves……

And relative size to my hat……

A Phytosaur skull still in it’s field jacket.

To finish up with my earlier blog, I drove out the south entrance and found the site where they were mining logs–these people are serious and only a few feet from the park boundary.  This, folks, is why we have national parks.

Some local color.  Very little decays in the northern Arizona sun, including dinosaur bones.  (Recall the Phytosaurs, Metoposaurs and Aetosaurs are not real dinosaurs, but their precursors.).   Oh, below is the last piece of bone glued in place….and now we know the length of this femur (it is inverted from the earlier blog photograph).

Stay tuned!

Metoposaurs and Aetosaurs

Saturday, February 23rd, 2019

Matt, the Curator of the museum collection here at Petrified Forest shows me the likeness of a Metoposaur on each side–an 8′ long lizard/salamander type of critter that lived about 220M years ago.  This is my next project.

This appears to be the left clavicle based upon the ray pattern which is bone, not tissue.  This plate was pretty much intact but also collected in the area were dozens of isolated fragments carried down by gravity over time.

Every piece must first be cleaned with a pin-vice, brush and perhaps a light water wash.

The next task is to assemble these parts–here are about 20 pieces that begin to take shape–a three day endeavor.  Some fit perfectly and some not.

While the glue is drying, I clean off this Aetosaur plate, we think–like an armadillo’s that articulate along each side of this critter.  This is very thin and was a challenge to assemble.  We make a top case and flip it over like an omelette.

With more glue to set up, I tackle this “jaw” which turned out to perhaps be a rib–species unknown.

Enter the wet lab.  After all this prepping and assembly, we take the matrix that we’ve saved and sift it through sieves down to 180 microns.

Here’s the washed material.  The right (coarsest) tray is simple to check out but the left one is extremely fine sand-like material

While sifting through this finest matrix, I do a rough calculation that there are 25,500,000 grains of sand here to look through!

This is the microscope view with of the second finest sieve with a 1 cm scale shown.  Each cm2 of the finest has about 2500 grains or 25/mm2.  This tests one’s patience but there are rewards…..

….Finding little critter teeth, also fish scales and the like.  Here are five teeth parts compared with a pencil tip.  The little triangle one at 8 o’clock is about 1 mm wide.  Some of these are Phytosaur teeth fragments (juveniles) and others are fish, perhaps in their diet or just hanging around.

The smallest is believed to be from a Xenosaur, but let me run this by the experts again.  Note the second tooth.

OK–enough dinos (proto-dinos actually).  Here are a few scenes around Holbrook AZ.

Today’s modern dinosaurs are likely ferro-cement or similar.  This is not an authentic teepee either.

This totem pole would never pass in Alaska.  Another roadside attraction.

We had two pretty good storms that closed I-40 and the park, twice–an unusual event.  Here the second storm if seen through the Airstream door.  Note the painted tree around the door frame turns dioramic into the bar at the right….an Airstream with class–and it will be featured in Airstream Life this summer…..   I’ll be on the road for a couple days–Denver, Berkeley, Albuquerque, Jackson Hole and then Washington DC for another stab at lobbying.  Stay tuned!

PeFo Phytosaurs

Saturday, February 9th, 2019

 

After a ridiculous 35 day government shutdown our National Parks are finally open so I hurry up to Petrified Forest National Park from Tucson where I’ve cooled (?) my heels for two weeks.  As a former NPS ranger, and now also retired from 35 years of dentistry, I’m anxious to get back into the saddle, so to speak.  National Parks allow volunteers to help out and I’ve always been interested in geology and paleontology.    PeFo supplies me with a simple campground and a magnetic sign for my car, and it’s a short walk to the office……

There are two labs, of sorts;  a paleontology prep lab (my assignment) and a demonstration lab which is available to visitors who can interact with the paleontologists a few days a week.  The staff here is incredibly educated not only in educating the visitors, but extending the science of the upper Triassic fossils in northern Arizona–chiefly Phytosaurs here at PeFo.

I spend most of my days looking through a dissecting microscope picking apart matrix from bone fragments, then carefully assembling the pieces into a complete anatomical structure.  The matrix is chiefly bentonite with calcite crystals and other exotics which are easily teased from the bones.  Take a look:

The whitish matrix is removed with a tungsten-carbide tipped tool.  The bone is a whitish mineral-replacement material surrounded by a thin iron oxide residue which allows separation.  It’s tedious to say the least and this prep lab houses thousands of specimens that need to be cleaned and reassembled–which is why I’m here.  My undergraduate degree was in Geology so here I go!

My first project was to prep and assemble a Phytosaur femur.  Phytosaurs were pre-dinosaurs and looked something like 25′ crocodile except more terrifying.  This was a small one which I named Otto.  Each black/white scale is 1 cm–which took me three days to assemble–about 35 pieces.  See below:

Some are extremely small.  I can’t say how detailed this process is but every piece of bone and matrix must be separated and later screened.  The right hand dot is about 1 mm wide.  The two trapezoid pieces to the left would amount to a large grain of sand in your shoe.  Everything is eventually accounted for.  For those who know me, this a good practice for patience, although not unlike dentistry….

My second project is to dissect out bones in what was thought to be skull fragments, but turned out to be a vertebrae with rib sections.  This specimen was cast in the field by an open “jacket” –a plaster mold poured over a partially excavated find.  It is separated from the earth matrix, brought to the lab and then taken apart.

Half way through, bones emerge.  The matrix flakes away however some of the bone material is very flaky and must be stabilized with a glue cut with acetone.  This is the test–separating matrix from bone!

Along this road to discovery, I uncover a small bone fragment about one inch long–still don’t know what it might be.  It broke in several pieces as I teased the matrix away.

Here the bone fragments can be seen as the matrix is removed.  Fractures are common and frustrating but with glue can be stabilized until exposed.

One can only stare through a dissecting scope for so long so I catch a ride with the road patrol rangers–you’ve seen them–cruising around our parks keeping track of everything.  I did this for 7 years in Grand Teton National Park and loved it.  So, after nearly 50 years am back in the saddle again.  Today, I took a drive into the Eastern Expansion area–a recently acquired region east of the hourglass of PeFo.  It’s amazing country with hints of 100 year old cattle grazing (fences, wells) to ancient Puebloan civilizations.  The scenery is exquisite.

Land forms are bizarre and the colors and geology amaze.  This is near the Blue Mesa stratigraphy which is upper Triassic.  There were no birds then, only reptiles anxiously competing for dominance.  Here and there, petrified logs are perched on tops of mounds of debris.  Utterly amazing.

Here is a 4′ diameter log emerging out of the surrounding debris; this was once a teaming jungle near the equator.  The ground is littered with beautiful fragments; we literally walk through a jewelry store.

Google Earth shows stark differences between each side of the Petrified Forest National Park boundary–here at North Rainbow Forest.  Log miners have stripped everything leaving nothing but tire tracks and pilfered sand.  This is the reason we have National Parks.

A small debris field of iron rich quartzite or chert pebbles exfoliating from the cliffs above–each like a gemstone and undisturbed.

A Marscape perhaps.

An ancient log slowly releases it’s chemistry back into the cauldron called Earth, to be recycled.  I am lucky to happen by–another million years and it would be gone…..  Below is the loop drive beyond the Painted Desert Inn, built in 1920 and remodeled by the CCC in 1938 when the bentonite foundation started swelling and fracturing the building.  This vista captures old and new.  It’s a privilege to be able to work again in our national parks–I hope you visit them and support them.  Stay tuned!


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