Holocene Plant Macrofossil

[Doctor Mud]

I had talked to @Peat Burns about posting something a little different on TFF.

Quaternary fossils from wetland deposits. Still fossils, but a bit different to what we mostly see on here.

 

I want to get better images. We need to set up the camera on the dissecting scope, so here are some rough and ready shots taken down the eyepiece with my phone. Better images to come.

 

These plant fragments tend to be tubular structures about 5 mm across. The Petri dish in the first shot is 5 cm across.

 

Locality: Holocene wetland deposits, New Zealand. These are about 2000 years old based on radiocarbon dating.

 

 

 

 

 

The last image shows some type of node I think, circular area about 3 mm across.

 

Im guessing this could be tissue from some sort of rhizome network of a wetland plant. I'd like to know as it is very common in some layers of the sediment and I tried radiocarbon dating it. It produced dates that are about 1000 years older than the rare leaves and seeds I could find and I'm curious as to what it is. 

In this situation you can get things over 1000 years older than they should be as the plants are actually using old carbon.

Some plants can use old dissolved inorganic carbon that can come from eroding limestone or groundwater.

 

Thanks for looking!

[Miocene_Mason]

Very cool! Thanks for sharing!

[izak_]

Thats really cool.

[doushantuo]

Great thinking,great post,Mud

More dulcaquicole/ephemeral/lacustrine/telmatological/paludinal posts,be they about the Quaternary or earlier

if you need it:I have pretty good Peridinales/palyno lit.

[Doctor Mud]

Thanks guys.

id love to know what plants these belonged too.

This is from a site I've been working on. A sediment core that spans the last 3000 years. I'm looking at the period leading up to the arrival of humans in New Zealand and the effect of forest clearance on the environment.

 

These plant fragments are really common in the sediments laid down before Maori forest clearance in the wetland catchment which happened about 500 years ago.

 

I need to get the camera set up and also try extracting some with just water.I often use potassium hydroxide to break down the sediments, but it takes its toll on the fossils sometimes.

 

 

 

 

[Peat Burns]

Whoa!  We've got to get some more charismatic plant macrofossils on here to represent our discipline! 

 

Those nebulous bits are a pain in the rear.  I much prefer plant disseminules, moss fragments, or even cladoceran ephippia ! 

[doushantuo]

fair enough,need i post this?

[doushantuo]

medeaniIndnon-pollen_palyHolocene_Peat,_Brazil.pdf

[Doctor Mud]

17 minutes ago, Peat Burns said:

Whoa!  We've got to get some more charismatic plant macrofossils on here to represent our discipline! 

 

Those nebulous bits are a pain in the rear.  I much prefer plant disseminules, moss fragments, or even cladoceran ephippia ! 

I hear you!

I didn't start with a bang but thought you might help me with these mystery fossils.

i optimistically thought I might get an ID and that you might recognize this based on the tissue structure or something.

 

you are right there are much cooler things to see in wetland sediments from macrofossils to microfossils.

This is the worst from this site which has a wealth of fossils. There are seeds from all sorts of plants, charcoal which indicates burning by the first humans to arrive in New Zealand and then the invertebrates.

 

The coolest I think are fossilised caddis fly cases, often with the larvae still preserved inside. I know - photos or it didn't happen.

 

Perhaps we could start a topic on this to showcase cool macrofossils?

[Peat Burns]

6 minutes ago, Doctor Mud said:

I hear you!

I didn't start with a bang but thought you might help me with these mystery fossils.

i optimistically thought I might get an ID and that you might recognize this based on the tissue structure or something.

 

you are right there are much cooler things to see in wetland sediments from macrofossils to microfossils.

This is the worst from this site which has a wealth of fossils. There are seeds from all sorts of plants, charcoal which indicates burning by the first humans to arrive in New Zealand and then the invertebrates.

 

The coolest I think are fossilised caddis fly cases, often with the larvae still preserved inside. I know - photos or it didn't happen.

 

Perhaps we could start a topic on this to showcase cool macrofossils?

I wish I could help you on your specimen.  I get similar stumpers, including abundant "rootlets" in the moss peats (both Amblystegiaceae and Sphagnaceae).  

 

Where should we start our topic?  When I get back to the office, I can post some pics.  I even have some entire macrofossil cranberry fruits I can post just in time for the Thanksgiving Holiday  (US) 

 

EDIT.  I forgot to mention I have found trichopteran cases, too.  BUT never with the larvae still inside! 

[Doctor Mud]

23 minutes ago, doushantuo said:

fair enough,need i post this?

Interesting stuff - the dastardly diagenesis strikes again!

This refers to stable isotopes.

I haven't seen anything about diagenesis and its effect on unstable isotopes - carbon 14. Unless you include replacement by mobile carbon - humic acids and carbonates. This is dealt with using acid base acid treatment to leach out the mobile carbon.

inadequate pretreatment can result in ages that are too old or too young. Including radiocarbon dates on dinosaur bones!

[doushantuo]

Ok:is anything on isotopes in cellulose,or anything treating sulfur diagenesis in peats any help?

[Peat Burns]

3 minutes ago, Doctor Mud said:

Interesting stuff - the dastardly diagenesis strikes again!

This refers to stable isotopes.

I haven't seen anything about diagenesis and its effect on unstable isotopes - carbon 14. Unless you include replacement by mobile carbon - humic acids and carbonates. This is dealt with using acid base acid treatment to leach out the mobile carbon.

inadequate pretreatment can result in ages that are too old or too young. Including radiocarbon dates on dinosaur bones!

And then there are those darn aquatic mosses that take up old carbon

[doushantuo]

for the general audience:

 

 

 

 

Use_of_lead-210_and_carbon-14_in_investigations_of (1).pdf

Ber-Inst-Erdwiss-Univ-Graz_8_0124-0127.pdf

 

outtake:

[doushantuo]

Kaisla_al_CG_2010.pdf

(Cold region Sphagnum isotopes)

 

 

 

[Doctor Mud]

14 minutes ago, Peat Burns said:

And then there are those darn aquatic mosses that take up old carbon

 

Yes, no amount of pretreatment will help there!

 

it can be frustrating when you see something that could be dateable but is likely to give wrong ages.

 

you can try paired dates (terrestrial plant and aquatic) but the offset can change through time. Some plants can use carbon dioxide or bicarbonate when co2 is limiting. An increase in nutrients and production (eutrophication) can soak up co2 and change the pH of the water (altering the composition of DIC). So changed in production and pH can change the offset.

 

Then there are those big bits of wood that cry out to be dated. But no bark, no date..... I'm fussy 

[doushantuo]

The_Ecology_of_Testate_Amoebae_Protists.pdf

[old bones]

This is very interesting stuff. I will enjoy seeing more like this.