EGU23-9558, updated on 18 Sep 2023
https://doi.org/10.5194/egusphere-egu23-9558
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Paleoprecipitations recorded by rock magnetic properties of stalagmites from the Gruta da Ceramica, Portugal

Ana Raquel Brás1, Eric Font1,2, Ana Sofia Reboleira3, Rui Melo1, Jorge E. Spangenberg4, and Paulo Fonseca2
Ana Raquel Brás et al.
  • 1University of Coimbra, Earth Science Department, Coimbra, Portugal (anaraquelmarcalo@gmail.com)
  • 2Instituto Dom Luís (IDL), Faculdade de Ciências, Universidade de Lisboa, Portugal (font_eric@hotmail.com; pefonseca@fc.ul.pt)
  • 3Departamento de Biologia Animal, Faculdade de Ciências, Centre for Ecology, Evolution and Environmental Changes (cE3c), Universidade de Lisboa, Lisbon, Portugal (asreboleira@fc.ul.pt)
  • 4Institute of Earth Surface Dynamics, University of Lausanne, 1015, Lausanne, Switzerland (jorge.spangenberg@unil.ch)

Speleothems are potential candidates for paleomagnetic and paleoclimatic reconstructions. Recent studies suggest that the abundance of magnetic minerals trapped in the calcite laminae of stalagmites is controlled by paleoclimatic and paleoenvironmental parameters including precipitation, vegetation and soil erosion. Here we test this hypothesis by studying speleothems from the Cerâmica cave in Penela, Portugal. We conducted carbon and oxygen isotopic analysis, together with the measurement of concentration-dependent magnetic proxies, including natural remanent magnetization, anhysteretic remanent magnetization, isothermal remanent magnetization and mass specific magnetic susceptibility. Results show a moderate but significant correlation between carbon and oxygen isotopic composition and the content in magnetite. An increase in magnetite content is correlated to increased precipitation and increased contribution of organic material. These results corroborate previous observations that rock magnetic properties of speleothems can provide useful information for paleoclimate reconstructions.

 

Acknowledgments: this work was funded by the Foundation of Sciences and Technology of Portugal (refs. PTDC/CTA-GEO/0125/2021; MIT-EXPL/ACC/0023/2021) and IDL (ref. FCT/UIDB/50019/2020).

 

 

 

 

How to cite: Brás, A. R., Font, E., Reboleira, A. S., Melo, R., E. Spangenberg, J., and Fonseca, P.: Paleoprecipitations recorded by rock magnetic properties of stalagmites from the Gruta da Ceramica, Portugal, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9558, https://doi.org/10.5194/egusphere-egu23-9558, 2023.