RT info:eu-repo/semantics/article
T1 Obtaining High‐Resolution Magnetic Records From Speleothems Using Magnetic Microscopy
A1 Borlina, Cauê S.
A1 Lima, Eduardo A.
A1 Feinberg, Joshua M.
A1 Plinio, Jaqueto
A1 Lascu, Ioan
A1 Trindade, Ricardo I. F.
A1 Font, Eric
A1 Sánchez Moreno, Elisa María
A1 Dimuccio, Luca Antonio
A1 Yokoyama, Yusuke
A1 Parés Casanova, Josep M.
A1 Weiss, Benjamin P.
A1 Dorale, Jeffrey A.
K1 Paleomagnetism
K1 Magnetic microscopy
K1 Speleothems
K1 Earth's magnetic field
K1 Paleomagnetismo
K1 Paleomagnetism
K1 Paleontología
K1 Paleontology
K1 Magnetismo
K1 Magnetism
K1 Arqueología
K1 Archaeology
AB Speleothems are mineral deposits capable of recording detrital and/or chemical remanent magnetization at annual timescales. They can offer high-resolution paleomagnetic records of short-term variations in Earth's magnetic field, crucial for understanding the evolution of the dynamo. Owing to limitations on the magnetic moment sensitivity of commercial cryogenic rock magnetometers (∼10−11 Am2), paleomagnetic studies of speleothems have been limited to samples with volumes of several hundreds of mm3, averaging tens to hundreds of years of magnetic variation. Nonetheless, smaller samples (∼1–10 mm3) can be measured using superconducting quantum interference device (SQUID) microscopy, with a sensitivity better than ∼10−15 Am2. To determine the application of SQUID microscopy for obtaining robust high-resolution records from small-volume speleothem samples, we analyzed three different stalagmites collected from Lapa dos Morcegos Cave (Portugal), Pau d'Alho Cave (Brazil), and Crevice Cave (United States). These stalagmites are representative of a range of magnetic properties and have been previously studied with conventional rock magnetometers. We show that by using SQUID microscopy we can achieve a five-fold improvement in temporal resolution for samples with higher abundances of magnetic carriers (e.g., Pau d'Alho Cave and Lapa dos Morcegos Cave). In contrast, speleothems with low abundances of magnetic carriers (e.g., Crevice Cave) do not benefit from higher resolution analysis and are best analyzed using conventional rock magnetometers. Overall, by targeting speleothem samples with high concentrations of magnetic carriers we can increase the temporal resolution of magnetic records, setting the stage for resolving geomagnetic variations at short time scales.
PB American Geophysical Union (AGU)
SN 1525-2027
YR 2024
FD 2024
LK http://hdl.handle.net/10259/10168
UL http://hdl.handle.net/10259/10168
LA eng
NO This work was partially supported by the National Science Foundation (NSF) Grants EAR-2044806, EAR-2044535, and EAR-2044506, Fundação para a Ciência e a Tecnologia (FCT-Portugal, PTDC/CTA-GEO/0125/2021 and MIT-EXPL/ACC/0023/2021), and the MIT-Portugal Seed Fund. CSB thanks The Morton K. Blaustein Scholars Fund. EMSM acknowledges the project BU037P23 of the Junta de Castilla y León and the European Research and Development Fund. Fieldwork and speleothem sampling in Portugal were authorized by Instituto da Conservação da Natureza e das Florestas (ICNF I.P.), under the responsibility of LD and supported by CEGOT I&D Unit (FCT-Portugal, UIDP/GEO/04084/2020_UC). Fieldwork and speleothem collection in Brazil were authorized by the Instituto Brasileiro do Meio Ambiente e dos Recursos Renováveis, and we thank the Centro Nacional de Pesquisa e Conservação de Cavernas (CECAV/ICMBio) for providing permission to collect stalagmite samples.
DS Repositorio Institucional de la Universidad de Burgos
RD 23-feb-2025