FN Archimer Export Format
PT J
TI Disentangling magnetic and environmental signatures of sedimentary 10Be/9Be records
BT 
AF Savranskaia, Tatiana
   Egli, Ramon
   Valet, Jean-Pierre
   Bassinot, Franck
   Meynadier, Laure
   Bourlès, Didier L.
   Simon, Quentin
   Thouveny, Nicolas
AS 1:1;2:1,2;3:1;4:3;5:1;6:4;7:4;8:4;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 Institut de Physique Du Globe de Paris, CNRS, UniveCENTRAL INSTITUTE FOR METEOROLOGY AND GEODYNAMICS (ZAMG)rsité de Paris, 75005, Paris, France
   Central Institute for Meteorology and Geodynamics (ZAMG), 1190, Vienna, Austria
   Laboratoire des Sciences Du Climat et de L’Environnement (CEA-CNRS-UVSQ), Domaine Du CNRS, 91198, Gif-sur-Yvette, France
   CEREGE UM34, Aix Marseille Univ, CNRS, IRD, INRAE, Coll France, 13545, Aix en Provence, France
C2 IPGP, FRANCE
   ZAMG, AUSTRIA
   CEA, FRANCE
   UNIV AIX MARSEILLE, FRANCE
IF 4.456
TC 2
UR https://archimer.ifremer.fr/doc/00682/79399/81939.pdf
   https://archimer.ifremer.fr/doc/00682/79399/81940.pdf
   https://archimer.ifremer.fr/doc/00682/79399/81941.pdf
   https://archimer.ifremer.fr/doc/00682/79399/81942.pdf
LA English
DT Article
CR IMAGES 1-MD101
   IMAGES 3-IPHIS-MD106
   IMAGES 4-MD111
   MD 148 / PECTEN
   MD 155 / MARCO-POLO2
   NAUSICAA-IMAGES 2-MD105
   SEYMAMA - MD 65
BO Marion Dufresne
DE ;Cosmogenic nuclides;Beryllium;Authigenic Be-10/Be-9 ratio;Geomagnetic field intensity;Matuyama-brunhes reversal
AB Reconstructions of the global production rate of the cosmogenic isotope 10Be from sedimentary records of authigenic 10Be/9Be ratios have been successfully used to obtain independent estimates of geomagnetic dipole moment variations caused by field excursions or reversals. In this study, we assess the reliability of 10Be/9Be as a proxy for the cosmogenic 10Be production rate by evaluating two potential biasing sources represented by sediment composition and climatic modulation. For this purpose, we compare five high-resolution 10Be/9Be records of the Matuyama-Brunhes (M-B) field reversal from sediment cores of the Indian, West Pacific, and North Atlantic oceans. Significant increase of 10Be/9Be ratios at 774 ka is explained in terms of the dominant control of geomagnetic modulation during the M-B reversal. Results do not support the existence of a direct proportionality between measured sedimentary 10Be/9Be ratio and cosmogenic 10Be production rate, as shown by 10Be/9Be records that offset relative to each other during and outside the M-B reversal. Residual differences between offset-corrected rescaled records do not appear to be related to an incomplete correction of variable sediment scavenging efficiencies by 9Be normalization. Instead, these differences can be explained by a common climatic modulation model, assuming a linear relation between 10Be/9Be and the global 10Be production rate with site- and time-dependent additive and multiplicative coefficients. These coefficients are linear functions of a single global climate proxy identified with the benthic O record. Additive coefficients are almost constant in time and can represent up to 60% of the average 10Be/9Be value during periods of stable field polarity. Multiplicative coefficients are also site-specific, with mean values representing the bulk scavenging efficiency of the site, and variations about this mean expressing a multiplicative climatic modulation of the 10Be production rate. The amplitude of this modulation amounts to 10–15% of the maximum variations recorded during the M-B reversal and is sufficiently large to mask minor variations of the dipole moment during stable polarity periods. Reconstructions of the geomagnetic dipole intensity can benefit from the information about climatic modulation effects gained with our modelling approach. Best suited sites for magnetic field reconstructions should be characterized by minimal Be-recycling contributions from ancient 10Be reservoirs and minimal climatic modulation, as far as it can be determined from relative comparisons with other records. These conditions are most likely encountered in open basins at sites (1) with 2.8 km water depth, (2) 200 km offshore, and (3) located underneath a large current system extending over regions with minimum terrigenous inputs. Scaling all records with respect to a chosen reference enables to produce 10Be/9Be stacks with reduced noise and short-term local environmental effects. Differences between stacks obtained in this manner highlight global climatic effects that need to be considered when generating calibrated reconstructions of the geomagnetic dipole moment. 
PY 2021
PD APR
SO Quaternary Science Reviews
SN 0277-3791
PU Elsevier BV
VL 257
UT 000631046400003
DI 10.1016/j.quascirev.2021.106809
ID 79399
ER

EF