Re: Giant oil field at/near Chicxulub

[Glen Ledingham <glenled@yahoo.com>]

The Cantarell field reservoir rock is a breccia
created by the Chicxlub impact, so Cantarell
field couldn't have predated the impact.  Oil was
not mobilized and didn't migrate from the Jurasic
source rocks until they had been buried
sufficiently to enter the oil window in the
Paleogene or Neogene.  The source rocks may have
extended into the impact area, and organic
material in them may have been burnt/vaporized,
but it wasn't oil at the time.  Similarly,
organic material in impact area sediments may
have been burnt/vaporized.    

In this area at least, we can't propose Mesozoic
oil robber barons or name them Petroraptor to
keep the discussion on topic.  I'd be happy to
continue it off-list.

Glen Ledingham

 
--- Richard Cowen <cowen@blueoakfarm.com> wrote:

> I know I shouldn't quote directly from Geology,
> but this is for  
> scientific discussion so it's probably OK. 
> Remember that I don't  
> know any of this for myself: I'm just quoting
> the authors.
> 
> The formation of the supergiant Cantarell oil
> field in the Gulf of  
> Mexico is a direct consequence of the K-T
> impact (Grajales-Nishimura  
> et al. 2000). At impact, the K-T boundary
> bolide shattered the  
> submerged carbonate platform that forms the
> western Yucatan  
> Peninsula, resulting in the Cantarell breccia.
> More than 80% of  
> recovered Cantarell oil derives from Late
> Jurassic source rock  
> (Guzman-Vega and Mello 1999). This figure
> indicates that Jurassic age  
> hydrocarbons were abundant at the time of
> impact, but not their  
> proximity to the Chicxulub target crust.
> Hydrocarbon inclusions  
> within diagenetic dolomite record the timing of
> oil migration at  
> Cantarell, showing that the breccia was
> permeated by hydrocarbons  
> prior to the precipitation of other minerals in
> the paragenetic  
> sequence (Martinez-Ibarra et al. 2003). While
> not providing an  
> absolute date, this does support a relatively
> early arrival of  
> hydrocarbons into the newly formed breccia
> reservoir, which increases  
> the probability that abundant hydrocarbons
> were present in the  
> Chicxulub target region at the time of impact.
> The ¶13C values of the  
> Cantarell whole oil range between -25ä and -27ä
> (Guzman-Vega and  
> Mello 1999), bracketing the globally averaged
> K-P boundary black  
> carbon (-25.8ä ± 0.6ä). Carbon cenospheres,
> IAS, and aciniform soot  
> are all produced simultaneously in modern
> furnaces from finely  
> dispersed organic-rich crust. Similarly,
> organic and mineral matter  
> excavated from the target crust by the K-P
> impact may have been  
> heated and dispersed sufficiently to produce a
> worldwide layering of  
> these three particle types.
>