Hunting the Late Cretaceous Aguja Formation at home!

[Coco]

Hi,

 

I ask myself a question : I have never heard of baking soda to clean sediment. What is it made of ? Limestone ? Marl ? Anything else ? I’m not sure I understand what "soda" is. Is it a drink or NaHCO₃ ?

Good luck with the future sorting and I wish you all the best.

 

Coco

[Troodon]

1 hour ago, Coco said:

NaHCO₃

Yes

I've just used water in my Aguja matrix and it does the job.

[Troodon]

4 hours ago, thelivingdead531 said:

? I don’t have a sieve at home, would that be a problem

It really helps get rid of the excess small matrix and reduces the volume significantly.  Makes sorting a lot easier.   Lots of the finds are 2 -5 mm

[hokietech96]

@thelivingdead531 You can use a spagehetti colander or window screen.

[Randyw]

11 minutes ago, Troodon said:

Yes

I've just used water in my Aguja matrix and it does the job.

I did the same. I wonder what the soda is supposed to do?

[Troodon]

18 minutes ago, hokietech96 said:

@thelivingdead531 You can use a spagehetti colander or window screen.

As long as the mesh/screen does not allow 2mm specimens to get through 

[Monica]

1 hour ago, Randyw said:

I did the same. I wonder what the soda is supposed to do?

 

I don't know what the baking soda is reacting with, but it definitely bubbled up quite a bit when I added the Aguja matrix to the baking soda-and-water mixture, and the large chunks of matrix broke up into squishy mud.

 

2 hours ago, Coco said:

Hi,

 

I ask myself a question : I have never heard of baking soda to clean sediment. What is it made of ? Limestone ? Marl ? Anything else ? I’m not sure I understand what "soda" is. Is it a drink or NaHCO₃ ?

Good luck with the future sorting and I wish you all the best.

 

Coco

 

Hi Coco!  As Frank (Troodon) confirmed, "baking soda" is the common name for NaHCO₃ (sodium bicarbonate/sodium hydrogen carbonate).

 

And thanks for the luck - I hope I find some additional goodies lurking in the matrix 

[Coco]

Thanks Monica

 

@Troodon What kind of sediment is baking soda used to break ?

 

Coco

[Troodon]

3 minutes ago, Coco said:

Thanks Monica

 

@Troodon What kind of sediment is baking soda used to break ?

 

Coco

It can help breakdown some tough clays.  However water seemed to work fine with the Aguja mix just minor clumping.  Will try it the next time I get some.

[Monica]

Happy Canada Day, everyone!!! 

 

I started the process of looking through the Aguja matrix that was sieved and dried.  After breaking up the dried mud chunks with my fingers over top of the sieve once again (so even more of the fine dust could be separated out from the larger chunks), I began to search through what was left behind in the sieve and this is what I found:

A carnivorous dinosaur tooth - woohoo!!! Frank @Troodon - Are these pictures clear enough to determine which dino group this little tooth came from?  Perhaps a dromaeosaurid?

 

[hokietech96]

Wow.  That is a nice looking tooth!

[Monica]

2 minutes ago, hokietech96 said:

Wow.  That is a nice looking tooth!

 

It's a tiny but terrific tooth - I'm very pleased with it 

 

Thanks for chiming in, Mark!

[Tidgy's Dad]

Great find, Monica. 

Happy Canada Day! 

[Monica]

Just now, Tidgy's Dad said:

Great find, Monica. 

Happy Canada Day! 

 

Thanks, Adam 

[Troodon]

cool tooth congrats its a nice one

 

Need to see the base, entire mesial carina and can you possibly take a sharper photo of the distal denticles they are fuzzy

[Scylla]

The baking soda usually reacts with acids to give off co2 bubbles. Maybe there are some organic acids or the matrix is slightly acidic. The bubbles would help break up clumps.

[Monica]

4 minutes ago, Troodon said:

cool tooth congrats its a nice one

 

Need to see the base, entire mesial carina and can you possibly take a sharper photo of the distal denticles they are fuzzy

 

Thanks for looking, Frank - I'll try to take better photos sometime today (it's sunny here today, so I should be able to make it happen )

[Monica]

3 minutes ago, Scylla said:

The baking soda usually reacts with acids to give off co2 bubbles. Maybe there are some organic acids or the matrix is slightly acidic. The bubbles would help break up clumps.

 

Hey Gus!  Thanks for checking in!  I know that baking soda is typically a weak base (although it can act as a proton donor), but I just never thought of rock/matrix as being acidic.  I know pretty much nothing about rock/matrix, though, so there you have it! 

[Scylla]

28 minutes ago, Monica said:

 

Hey Gus!  Thanks for checking in!  I know that baking soda is typically a weak base (although it can act as a proton donor), but I just never thought of rock/matrix as being acidic.  I know pretty much nothing about rock/matrix, though, so there you have it! 

Yup, limestone based soils tend to be basic and silica rich soils are more acidic. Of course decaying organic material can make them acidic too. 

[grandpa]

Monica,

That's a great find.  I'm so happy for you!  

Happy Canada Day!  I remember spending Canada Day 2006 in Drumheller, Alberta and enjoying the parade with the local folks, a very friendly group and good times.

BTW, regarding use of Sodium Bicarbonate on the matrix, I've been interested in the possible chemistry at work here, so I did a little research.  I found an article that described the aguja fm. as a gypsum and clay soil.  Gypsum is calcium sulfate and is relatively insoluble.  Clay can have a varied chemistry depending on the anions present but is generally characterized as a combination of aluminum oxide, silicon dioxide and water; aluminum oxide and SiO2 are likewise insoluble.  Mixing the sodium bicarbonate with gypsum and clay + H2O yields quite a soup of ions.  If we play with these we can get aluminum sulfate (soluble) and calcium bicarbonate (also soluble), plus ions of sodium, oxygen, hydrogen and SiO2.  How these combine stoicheometrically depends in part on the actual clay makeup.  Needless to say, some gas can be released (O2, H2, CO2?) and (most importantly for our application) the matrix containing the fossils will be converted from insoluble to soluble in water; i.e., it will break up and dissolve. That's my best WAG of the chemistry involved.  Perhaps a soil scientist can pitch in and give us a better understanding.  The clay chemistry for that given location would be the main variable, me thinks. 

[Monica]

Thanks for the detailed explanation, @grandpa! 

[Monica]

Frank @Troodon - hopefully these photos are better...(my kids lent me some of their white Play-Doh )

[Nimravis]

Great find Monica, congrats.

[Troodon]

Sorry to be a pain but I still need to see that mesial carina from that edge not a lateral shot.  The rest are perfect thanks.  Play-doh works great

[Monica]

Thanks, Ralph @Nimravis! 

 

Frank @Troodon - I have to admit that I needed to look up which part of the tooth was the "mesial carina", but I think I figured it out!  Here are a couple of pictures of the mesial carina at slightly different angles - I don't see any evidence of serrations: