Houston Geological SocietyAcademic Liaison Committee

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HGS Academic LiaisonPresentation Archives

Extreme Paleocene - Eocene Sea Level Fluctuation(s) in the Gulf of Mexico:A Hypothesis

Part IIIc: Effects of Re-connection

Josh Rosenfeld and Jim PindellCerro Azul #4 blow-out, Veracruz, Mexico February 1916

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Sierra de Chiapas – El Bosque Fm.

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“Eocene” Unconformity - Veracruz Foldbelt

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Sierra de Chiapas – El Bosque Fm.

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Sierra de Chiapas – El Bosque Fm.

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Sierra de Chiapas – El Bosque Fm.

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What about Eocene salt (?)

• Evaporation > 90% required to precipitate salt.(carbonates/gypsum volumetrically minor)

• NaCl in sea water ~ 35,000 ppm by weight.

• Total evaporation of a 3000 meter seawater column yields ± 48 meters of halite. Thick saltdeposits require renewed seawater influx.

• It is unlikely that salt accumulated, except perhaps in the central Gulf.

• Any thin salt deposits would have been subjectto dissolution upon refilling of Gulf.

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Lower Tertiary Source Rocks

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Lower Tertiary Source Rocks; in Point Coupe and St Landry Parishes, LA

Data From Sassen and Chinn, 1990

Fm. Age Depth Range TOC% HI____

Sparta M. Eocene 11,163 – 11,526 1.3 – 8.1 198-843(4 wells)

Wilcox L. Eocene 13,137 – 14,276 1.5 – 5.2 134-364(3 wells)

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Lower Tertiary Source Rocks in the Amoco MC-84 Well

From Wagner, Sofer and Claxton, 1994

Hyper-saline or Condensed Section??

Depth TOC% HI Amorph. Ker.%

14,645’ 3.05 541 60

14,650’ 2.69 468 60

14,810’ 3.30 536 90

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Some Conclusions

• There was at least one major G.O.M. drawdown in the Early Eocene.

• There is a large paleocanyon under the Rio Grande in the Vicksburg Embayment.

• Wilcox sands should be widespread in the deep Gulf…(Deltaic? Neritic?)

• Everyone is invited to play!!!