Giant oil field at/near Chicxulub

[Richard Cowen <cowen@blueoakfarm.com>]

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 -25‰ and -27‰ (Guzman-Vega and  
Mello 1999), bracketing the globally averaged K-P boundary black  
carbon (-25.8‰ ± 0.6‰). 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.