<p>Depends upon the species. <em>If</em> the pollen spores are large enough, <em>and</em> of wide spatial distribution, <em>and</em> easily recognizable, <em>and</em> preserves well in sediments, <em>and</em> of distinctive age range (geologically), then it could be used. </p>

<p>There have been mistakes in the past where modern pollen collected in microscopic pores in older rock, giving the illusion of rock ages much younger than they really are, so precautions against sample contamination are of paramount importance. </p>

CC BY-SA 3.0
2015-12-18T14:05:58.577Z
2015-12-18T14:05:58.577Z
Gordon Stanger
<p>In addition to what @GordonStanger said, there are a few other points to consider.</p>

<ul>
<li>Pollens and spores are made out of sporopollenin which <a href="https://earthscience.stackexchange.com/a/409/87">preserves way better than what one would expect</a>.</li>
<li>Although there isn't probably a perfect 1-to-1 correspondance between pollen morphospecies and the plant species that produced them, there is still a wide variety of pollen morphospecies, and they still have usable first and last occurrences.</li>
<li>But the main point is that pollen are produced by <strong>land</strong> plants, meaning they have a continental origin. Yet, because some of them are transported by the wind or by water, you can still find them in marine sediments on top of finding them in terrestrial sediments, and this is a very valuable property: indeed marine sediments are easy to date precisely (thanks to magnetostratigraphy and the myriad of planktonic microfossil that sediment in them) while terrestrial sediments are really not (apart from pollen, small mammal remains can be used during the Cenozoic, but otherwise there really isn't any widespread biomarkers in terrestrial sediments, and geochronological dating is rarely possible). Pollen morphospecies first and last occurrences can thus be, in theory, dated with some accuracy thanks to marine sediments while being applicable to hard-to-date terrestrial sediments.</li>
</ul>

CC BY-SA 3.0
2016-03-19T09:28:01.357Z
2016-03-19T09:28:01.357Z
2017-04-13T12:50:30.540Z
plannapus
<p>What makes pollen varieties useful index fossils? Should pollen not be a poor index fossil?</p>

CC BY-SA 3.0
2015-12-18T02:38:11.920Z
No two species have the same pollen.  Identifying that is key to understanding what the climate was like back then.
JohnWDailey
CC BY-SA 3.0
2015-12-19T18:09:54.690Z
Palynology tag might be useful in the future.
Siv
<paleontology><stratigraphy><geobiology><archaeology><paleobotany>
What makes pollen varieties useful index fossils?
Lucian09474
# What makes pollen varieties useful index fossils?

(Asked by: username_0 on 2015-12-18)

What makes pollen varieties useful index fossils? Should pollen not be a poor index fossil?

**Tags:** paleontology, stratigraphy, geobiology, archaeology, paleobotany

> **Comments:**
> **username_1**: No two species have the same pollen.  Identifying that is key to understanding what the climate was like back then.  
> **username_2**: Palynology tag might be useful in the future.  

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## 2 answers

### Answer by username_3 on 2015-12-18. Score: 3

Depends upon the species. *If* the pollen spores are large enough, *and* of wide spatial distribution, *and* easily recognizable, *and* preserves well in sediments, *and* of distinctive age range (geologically), then it could be used.

There have been mistakes in the past where modern pollen collected in microscopic pores in older rock, giving the illusion of rock ages much younger than they really are, so precautions against sample contamination are of paramount importance.


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### Answer by username_4 on 2016-03-19. Score: 2

In addition to what @username_3 said, there are a few other points to consider.

* Pollens and spores are made out of sporopollenin which [preserves way better than what one would expect](https://earthscience.stackexchange.com/a/409/87).
* Although there isn't probably a perfect 1-to-1 correspondance between pollen morphospecies and the plant species that produced them, there is still a wide variety of pollen morphospecies, and they still have usable first and last occurrences.
* But the main point is that pollen are produced by **land** plants, meaning they have a continental origin. Yet, because some of them are transported by the wind or by water, you can still find them in marine sediments on top of finding them in terrestrial sediments, and this is a very valuable property: indeed marine sediments are easy to date precisely (thanks to magnetostratigraphy and the myriad of planktonic microfossil that sediment in them) while terrestrial sediments are really not (apart from pollen, small mammal remains can be used during the Cenozoic, but otherwise there really isn't any widespread biomarkers in terrestrial sediments, and geochronological dating is rarely possible). Pollen morphospecies first and last occurrences can thus be, in theory, dated with some accuracy thanks to marine sediments while being applicable to hard-to-date terrestrial sediments.


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