Controls on the Mg Cycle in the Tropics: Insights from a Case Study at the Luquillo Critical Zone Observatory

Maria Chapela-Lara, Heather Buss, Philip A E Pogge von Strandmann, Celine Dessert, Jerome Gaillardet

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To better constrain the mechanisms controlling short-term Mg dynamics in the tropics, we sampled critical zone compartments of a catchment covered by thick, highly weathered regolith. Our Mg and δ26Mg data indicate that rain is a main source of Mg throughout the regolith, and we do not observe Mg isotope offsets in vegetation/surficial pore water. In addition to rain and weathering inputs, a heavy isotope excursion at ∼1 m depth indicates a fractionation process, likely sorption-desorption or clay dissolution. Stream water δ26Mg reflects inputs from rain and a heavy source, likely differential weathering along deep bedrock fractures.
Original languageEnglish
Pages (from-to)200-203
Number of pages4
JournalProcedia Earth and Planetary Science
Early online date26 Aug 2014
Publication statusPublished - 2014

Bibliographical note

Conference proceeding: Geochemistry of the Earth's surface GES-10 Paris France, 18-23 August, 2014.


  • Mg cycle
  • Tropical Weathering
  • Mg isotopes
  • Critical Zone
  • Regolith
  • Soil

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  • Projects

    LCZO: Luquillo Critical Zone Observatory

    Buss, H. L., Brantley, S. L., Scatena, F. N., Silver, W., Plante, A., Willenbring, J., McDowell, W., Shanley, J., White, A. F., Scholl, M., Johnson, A., Jerolmack, D., Horton, B., Chapela Lara, M. & Moore, O. W.


    Project: Research

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