Stalagmite paleomagnetic record of a quiet mid-to-late Holocene field activity in central South America

Author(s):Show less -

Jaqueto, Plinio ; Trindade, Ricardo I. F. ; Terra-Nova, Filipe ; Feinberg, Joshua M. ; Novello, Valdir F. ; Strikis, Nicolas M. ; Schroedl, Peter ; Azevedo, Vitor ; Strauss, Beck E. ; Cruz, Francisco W. ; Cheng, Hai ; Edwards, R. Lawrence

• Document type: Journal article
• Source: NATURE COMMUNICATIONS; v. 13, n. 1, p. 10-pg., 2022-03-15.

Abstract

Speleothems can provide high-quality continuous records of the direction and relative paleointensity of the geomagnetic field, combining high precision dating (with U-Th method) and rapid lock-in of their detrital magnetic particles during calcite precipitation. Paleomagnetic results for a mid-to-late Holocene stalagmite from Dona Benedita Cave in central Brazil encompass similar to 1900 years (3410 BP to 5310 BP, constrained by 12 U-Th ages) of paleomagnetic record from 58 samples (resolution of similar to 33 years). This dataset reveals angular variations of less than 0.06 degrees yr(-1) and a relatively steady paleointensity record (after calibration with geomagnetic field model) contrasting with the fast variations observed in younger speleothems from the same region under influence of the South Atlantic Anomaly. These results point to a quiescent period of the geomagnetic field during the mid-to-late Holocene in the area now comprised by the South Atlantic Anomaly, suggesting an intermittent or an absent behavior at the multi-millennial timescale. (AU)

• FAPESP's process: 16/15807-5 - Paleoclimate and paleoenvironmental reconstructions over the last glacial period in the mid-west Brazil
• Grantee: Valdir Felipe Novello
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/07410-3 - Persistence of the South Atlantic Anomaly in geomagnetic observations, field models and numerical dynamos
• Grantee: Filipe Terra Nova dos Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/06709-8 - Speleothem magnetism from the Last Glacial Maximum to the Holocene in South America
• Grantee: Plinio Francisco Jaqueto
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 18/15774-5 - Geochronoloy of sedimentary deposits in caves from São Desiderio region: implications for speleogenesis and geomorphological evolution of West Bahia State
• Grantee: Ivo Karmann
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/24870-2 - Environmental significance of speleothem magnetism
• Grantee: Plinio Francisco Jaqueto
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/50085-3 - PIRE: climate research education in the Americas using tree-ring speleothem examples (PIRE-CREATE)
• Grantee: Francisco William da Cruz Junior
• Support Opportunities: Research Projects - Thematic Grants