Hyperthermal events recorded in the Palaeogene carbonate sequence of southern Gulf of Mexico—Santa Elena borehole, Yucatan Peninsula

• Published in: Geological journal (Chichester, England) Vol. 57; no. 1; pp. 99 - 113
• Main Authors: García‐Garnica, Edgar M., Pérez‐Cruz, Ligia
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.01.2022; Wiley Subscription Services, Inc
• Subjects: Aluminum; Barium; Boreholes; Calcite; Calcium; Carbonate rocks; Carbonates; Chemical precipitation; Chicxulub impact crater; Climate change; Condensates; continental shelf; Continental shelves; Dilution; Dissolution; Dissolving; Eocene; Eocene Thermal Maximum 2; Eustatic changes; Evaporation; Evaporites; extreme precipitation; geochemistry; Iron; Magnetic permeability; Magnetic susceptibility; Nutrients; Palaeocene; Palaeocene‐Eocene Thermal Maximum; Palaeogene; Paleocene; Precipitation; Productivity; Records; sea‐level rise; Silicon; Thermocline; Trace elements; Trace elements (nutrients); Trophic levels; Yucatan Peninsula; Mexico
• ISSN: 0072-1050; 1099-1034
• DOI: 10.1002/gj.4285

Based on geochemical and magnetic susceptibility analyses, maximum warming events (hyperthermal) in the Palaeogene are recognized in the carbonate rocks of the Santa Elena borehole (SEB) in the Yucatan Peninsula, the Palaeocene‐Eocene Thermal Maximum (PETM) and the Eocene Thermal Maximum 2 (ETM‐2). The site records the continental shelf marine response during these global events. Major and trace element records (Al, Ba, Ca, Fe, K, Si, and Ti), Ca/Fe, Si/Al ratios, and magnetic susceptibility are used as proxies of terrigenous input, and Ba/Al ratio as a proxy of palaeoproductivity. The hyperthermal events are characterized by the dilution and/or dissolution of biogenic carbonates. The high input of terrigenous materials is linked to extreme precipitation, common during these warming events. Our records suggest a decrease in palaeoproductivity associated with a nutrients gradient in a shallow ecosystem, with deeper thermocline and stratified column water. The PETM is characterized by high eustatic sea‐level conditions, with a high contribution of detrital material, indicating sedimentary condensation and marked increase in precipitation, calcite dilution and/or dissolution, and low productivity. The ETM‐2 event is less extreme than the PETM, with high precipitation, although evaporation could also play an important role, as evidenced by the presence of evaporites in this interval. These changes might affect the higher trophic levels of the shelf sea ecosystem, declining productivity. The study contributes to our understanding of the global and regional effects of these past warming events and the future climate change. Proxy records in the carbonate rocks of the Santa Elena borehole in the Yucatan platform of the Palaeogene reveal abrupt shifts in two conspicuous intervals with sedimentation patterns modified by climate changes. These are related to rapid extreme global warming events, particularly those of larger magnitude in the early Palaeogene hyperthermal events, the Palaeocene‐Eocene Thermal Maximum, and the Eocene Thermal Maximum 2. The events are distinguished by the dilution and/or dissolution of biogenic carbonates, high input of terrigenous materials linked to extreme precipitation, and decrease in palaeoproductivity.