@Article{JaquetoTFCNSCSK:2021:MaMiSp,
               author = "Jaqueto, Plinio and Trindade, Ricardo I. F. and Feinberg, Joshua 
                         M. and Carmo, Janine and Novello, Valdir F. and Strikis, Nicolas 
                         M. and Cruz, Francisco W. and Shimizu, Mar{\'{\i}}lia Harumi and 
                         Karmann, Ivo",
          affiliation = "{Universidade de S{\~a}o Paulo (USP)} and {Universidade de 
                         S{\~a}o Paulo (USP)} and {University of Minnesota} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {Universidade de 
                         S{\~a}o Paulo (USP)} and {Universidade Federal Fluminense (UFF)} 
                         and {Universidade de S{\~a}o Paulo (USP)} and {Instituto Nacional 
                         de Pesquisas Espaciais (INPE)} and {Universidade de S{\~a}o Paulo 
                         (USP)}",
                title = "Magnetic Mineralogy of Speleothems From Tropical-Subtropical Sites 
                         of South America",
              journal = "Frontiers in Earth Science",
                 year = "2021",
               volume = "9",
                pages = "e634482",
                month = "Apr.",
             keywords = "environmental magnetism, speleothem magnetism, South America, rock 
                         magnetism, karst system, stalagmites.",
             abstract = "Fe-bearing minerals are a tiny fraction of the composition of 
                         speleothems. They have their origin in the karst system or are 
                         transported from the drainage basin into the cave. Recent studies 
                         on the magnetism of speleothems focused on the variations of their 
                         magnetic mineralogy in specific time intervals and are usually 
                         limited to a single sample. In this study, we describe a database 
                         of environmental magnetism parameters built from 22 stalagmites 
                         from different caves located in Brazil (South America) at 
                         different latitudes, comprising different climates and biomes. The 
                         magnetic signal observed in these stalagmites is dominated by 
                         low-coercivity minerals (similar to 20 mT) whose magnetic 
                         properties resemble those of the magnetite formed in pedogenic 
                         environments. Also, a comparison with few samples from soils and 
                         the carbonate from cave's walls shows a good agreement of the 
                         magnetic properties of speleothems with those of soil samples, 
                         reinforcing previous suggestions that in (sub-)tropical regimes, 
                         the dominant magnetic phase in speleothems is associated with the 
                         soil above the cave. Spearman's rank correlation points to a 
                         positive strong correlation between magnetic concentration 
                         parameters (mass-normalized magnetic susceptibility, natural 
                         remanent magnetization, anhysteretic remanent magnetization, and 
                         isothermal remanent magnetization). This implies that ultrafine 
                         ferrimagnetic minerals are the dominant phase in these 
                         (sub-)tropical karst systems, which extend across a diverse range 
                         of biomes. Although the samples are concentrated in the savannah 
                         biome (Cerrado) (similar to 70%), comparison with other biomes 
                         shows a higher concentration of magnetic minerals in speleothem 
                         underlying savannahs and lower concentration in those underlying 
                         moist broadleaf forests (Atlantic and Amazon biome) and dry 
                         forests (Caatinga). Thus, rainfall, biome, and epikarst dynamics 
                         play an important role in the concentration of magnetic minerals 
                         in speleothems in (sub-)tropical sites and indicate they can be an 
                         important target for paleoenvironmental research in cave 
                         systems.",
                  doi = "10.3389/feart.2021.634482",
                  url = "http://dx.doi.org/10.3389/feart.2021.634482",
                 issn = "2296-6463",
             language = "en",
           targetfile = "feart-09-634482.pdf",
        urlaccessdate = "09 maio 2024"
}