<p>The Paleocene-Eocene Thermal Maximum (PETM) is a well-studied warming event near the Paleocene-Eocene boundary.<br>
It is characterized by its extreme warming rate: from onset to recovery the event lasted ca. 100 kyrs, and the global temperature is thought to have increased by ~6 °C in barely 20 kyrs.<br>
This event is of particular interest not only for its $\delta^{18}\rm O$ but also a sharp negative excursion in the $\delta^{13}\rm C$, implying a strong input of $^{13}\rm C$-depleted carbon into the system.  </p>

<p><img src="https://i.sstatic.net/UmI5m.png" alt="Isotopic curves of Paleogene climate, showing abrupt peak at PETM"></p>

<p><sub>Simplified and redrawn after Zachos et al. 2001</sub></p>

<p>One frequently invoked hypothesis to explain this input is the leakage of methane from clathrates trapped in seafloor sediments.<br>
Being a paleontologist and not a geochemist, I struggle to understand the actual chemical mechanism involved.
<strong>I was thus wondering if someone could explain the mechanisms allowing the destabilization of methane clathrates at the same time on a global scale.</strong><br>
If it's just linked to a temperature threshold, how come it wasn't reach prior to that (warmer temperature were reached during the Cretaceous)?</p>

CC BY-SA 3.0
2014-11-21T14:26:43.180Z
As well as destabilization of clathrates, the finger is often pointed at the 'cooking' of organic rich sediments in the proto-North Atlantic. Today we find Paleogene lavas above carbon-rich sediments - eg. the West of Shetland oil fields.
winwaed
CC BY-SA 3.0
2014-11-21T14:33:57.813Z
@winwaed Are you refering to studies like [Storey et al 2007](http://www.sciencemag.org/content/316/5824/587.short)? Never heard of that theory before today, this is interesting.
plannapus
CC BY-SA 3.0
2014-11-21T16:06:10.807Z
Well one hypothesis doesn't nullify the other, one can easily imagine both phenomena to have co-occurred and co-contributed.
plannapus
CC BY-SA 3.0
2014-11-21T21:51:54.143Z
@plannapus I was thinking of articles in Geoscientist over the past few years. Unfortunately I don't have the articles handy to find their source references. Yes it could either or both. My understanding was a strong link between the carbon and the volcanism, but uncertainty as to the exact mechanism - cooked sediments and clathrates being the leading contenders.
winwaed
<geochemistry><paleoclimatology><clathrates>
Release mechanism for methane clathrate at the PETM
plannapus
# Release mechanism for methane clathrate at the PETM

(Asked by: username_0 on 2014-11-21)

The Paleocene-Eocene Thermal Maximum (PETM) is a well-studied warming event near the Paleocene-Eocene boundary.  
It is characterized by its extreme warming rate: from onset to recovery the event lasted ca. 100 kyrs, and the global temperature is thought to have increased by ~6 °C in barely 20 kyrs.  
This event is of particular interest not only for its $\delta^{18}\rm O$ but also a sharp negative excursion in the $\delta^{13}\rm C$, implying a strong input of $^{13}\rm C$-depleted carbon into the system.

![Isotopic curves of Paleogene climate, showing abrupt peak at PETM](https://i.sstatic.net/UmI5m.png)

Simplified and redrawn after Zachos et al. 2001

One frequently invoked hypothesis to explain this input is the leakage of methane from clathrates trapped in seafloor sediments.  
Being a paleontologist and not a geochemist, I struggle to understand the actual chemical mechanism involved.
**I was thus wondering if someone could explain the mechanisms allowing the destabilization of methane clathrates at the same time on a global scale.**  
If it's just linked to a temperature threshold, how come it wasn't reach prior to that (warmer temperature were reached during the Cretaceous)?

**Tags:** geochemistry, paleoclimatology, clathrates

> **Comments:**
> **username_1**: As well as destabilization of clathrates, the finger is often pointed at the 'cooking' of organic rich sediments in the proto-North Atlantic. Today we find Paleogene lavas above carbon-rich sediments - eg. the West of Shetland oil fields.  
> **username_0**: @username_1 Are you refering to studies like [Storey et al 2007](http://www.sciencemag.org/content/316/5824/587.short)? Never heard of that theory before today, this is interesting.  
> **username_0**: Well one hypothesis doesn't nullify the other, one can easily imagine both phenomena to have co-occurred and co-contributed.  
> **username_1**: @username_0 I was thinking of articles in Geoscientist over the past few years. Unfortunately I don't have the articles handy to find their source references. Yes it could either or both. My understanding was a strong link between the carbon and the volcanism, but uncertainty as to the exact mechanism - cooked sediments and clathrates being the leading contenders.  

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## 0 answers

