Advanced search
Start date
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Paleoproterozoic Geomagnetic Field Strength From the Avanavero Mafic Sills, Amazonian Craton, Brazil

Full text
Di Chiara, A. [1, 2] ; Muxworthy, A. R. [3] ; Trindade, R. I. F. [1] ; Bispo-Santos, F. [1]
Total Authors: 4
[1] Univ Sao Paulo, Dept Geofis, IAG, Insituto Astron Geofis & Ciencias Atmosfer, Sao Paulo - Brazil
[2] Plymouth Univ, Sch Geog Earth & Environm Sci SoGEES, Plymouth, Devon - England
[3] Imperial Coll London, Dept Earth Sci & Engn, Nat Magnetism Grp, London - England
Total Affiliations: 3
Document type: Journal article
Source: GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS; v. 18, n. 11, p. 3891-3903, NOV 2017.
Web of Science Citations: 0

A recent hypothesis has suggested that Earth's inner core nucleated during the Mesoproterozoic, as evidenced by a rapid increase in the paleointensity (ancient geomagnetic field intensity) record; however, paleointensity data during the Paleoproterozoic and Mesoproterozoic period are limited. To address this problem, we have determined paleointensity from samples from three Paleoproterozoic Avanavero mafic sills (Amazonian Craton, Brazil): Cotingo, 1,782 Ma, Puiua, 1,788 Ma, and Pedra Preta, 1,795 Ma. We adopted a multiprotocol approach for paleointensity estimates combining Thellier-type IZZI and LTD-IZZI methods, and the nonheating Preisach protocol. We obtained an average VDM value of 1.30.7 x 10(22)Am(2) (Cotingo) of 2.00.4 x 10(22)Am(2) (Puiua) and 64 x 10(22)Am(2) (Pedra Preta); it is argued that the Cotingo estimate is the most robust. Our results are the first data from the upper Paleoproterozoic for South America and are comparable to data available from other regions and similar periods. The new data do not invalidate the hypothesis of that Earth's inner core nucleated during the Mesoproterozoic. (AU)

FAPESP's process: 13/08938-8 - Precambrian paleointensity from the study of magmatic units of South America
Grantee:Anita Di Chiara
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 14/19509-3 - Palaeointensity of Proterozoic magmatic rocks from South America using the Preisach method
Grantee:Anita Di Chiara
Support type: Scholarships abroad - Research Internship - Post-doctor
FAPESP's process: 16/06114-6 - The Neoproterozoic Earth System and the rise of biological complexity
Grantee:Ricardo Ivan Ferreira da Trindade
Support type: Research Projects - Thematic Grants