Earth-prints repository, logo   DSpace

About DSpace Software
|earth-prints home page | roma library | bologna library | catania library | milano library | napoli library | palermo library
Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/9097

Authors: Sagnotti, L.*
Scardia, G.
Giaccio, B.
Liddicoat, J. C.
Nomade, S.
Renne, P. R.
Sprain, C. J.
Title: Extremely rapid directional change during Matuyama-Brunhes geomagnetic polarity reversal
Title of journal: Geophysical Journal International
Series/Report no.: 2/199 (2014)
Issue Date: 18-Sep-2014
DOI: 10.1093/gji/ggu287
Keywords: geomagnetic field reversal
magnetostratigraphy
Matuyama-Brunhes (M-B) transition
Abstract: We report a palaeomagnetic investigation of the last full geomagnetic field reversal, the Matuyama-Brunhes (M-B) transition, as reserved in a continuous sequence of exposed lacustrine sediments in the Apennines of Central Italy. The palaeomagnetic record provides the most direct evidence for the tempo of transitional field behaviour yet obtained for the M-B transition. 40Ar/39Ar dating of tephra layers bracketing the M-B transition provides high-accuracy age constraints and indicates a mean sediment accumulation rate of about 0.2 mm yr–1 during the transition. Two relative palaeointensity (RPI) minima are present in the M-B transition. During the terminus of the upper RPI minimum, a directional change of about 180 ◦ occurred at an extremely fast rate, estimated to be less than 2 ◦ per year, with no intermediate virtual geomagnetic poles (VGPs) documented during the transit from the southern to northern hemisphere. Thus, the entry into the Brunhes Normal Chron as represented by the palaeomagnetic directions and VGPs developed in a time interval comparable to the duration of an average human life, which is an order of magnitude more rapid than suggested by current models. The reported investigation therefore provides high-resolution integrated palaeomagnetic and radioisotopic data that document the fine details of the anatomy and tempo of the M-B transition in Central Italy that in turn are crucial for a better understanding of Earth’s magnetic field, and for the development of more sophisticated models that are able to describe its global structure and behaviour.
Appears in Collections:04.05.02. Geomagnetic field variations and reversals
Papers Published / Papers in press

Files in This Item:

File Description SizeFormatVisibility
Sagnotti et al 2014 Geophys. J. Int.-1110-24.pdfMain article4.53 MBAdobe PDFonly authorized users View/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.


Share this record
Del.icio.us

Citeulike

Connotea

Facebook

Stumble it!

reddit


 

Valid XHTML 1.0! ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software. CINECA