Publication Date:
2023-12-14
Description:
〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The production rates of cosmogenic radionuclides, such as 〈sup〉10〈/sup〉Be, 〈sup〉14〈/sup〉C, and 〈sup〉36〈/sup〉Cl, in the Earth's atmosphere vary with the geomagnetic field and solar activity. For the first time, the production rates of several cosmogenic nuclides are estimated for the past 100 ka based on global, time‐dependent geomagnetic field models and a moderate solar‐activity level. In particular, the production rates were high with no notable latitudinal dependence during the Laschamps geomagnetic excursion (41 ka BP). The mean global production of 〈sup〉10〈/sup〉Be over the Laschamps excursion was more than two times greater than the present‐day one, whereas the increase was 1.9 times for the Norwegian‐Greenland Sea excursion (∼65 ka), and only 1.3 times for the Mono Lake/Auckland excursion (∼34 ka). All analyzed geomagnetic field models covering the past 100 ka, including the modern and Holocene epochs, lead to hemispheric asymmetry in the production rates, persistent overall time ranges, and reflected in the time‐averaged nuclide production rates. Production rates predicted by the geomagnetic field models are in good agreement with actual measurements from ice cores and sediment records. These global, long‐term production rates are important for a wide range of studies that employ cosmogenic nuclides as a proxy/tracer of different Earth system processes.〈/p〉
Description:
Key Points:
〈list list-type="bullet"〉
〈list-item〉
〈p xml:lang="en"〉We estimated the atmospheric production rates of cosmogenic radionuclides using global geomagnetic field models covering the past 100 ka〈/p〉〈/list-item〉
〈list-item〉
〈p xml:lang="en"〉The results show the importance of the multipolar components of the field during the Laschamps excursion〈/p〉〈/list-item〉
〈list-item〉
〈p xml:lang="en"〉The variations in production rates predicted by the models agree well with the actual measurements from ice cores〈/p〉〈/list-item〉
〈/list〉
〈/p〉
Description:
Academy of Finland
http://dx.doi.org/10.13039/501100002341
Description:
University of Oulu
Description:
China Scholarship Council
http://dx.doi.org/10.13039/501100004543
Description:
Helmholtz‐Zentrum Potsdam ‐ Deutsches GeoForschungsZentrum GFZ
http://dx.doi.org/10.13039/501100010956
Description:
https://earthref.org/ERDA/2543/
Description:
https://earthref.org/ERDA/2498/
Description:
https://earthref.org/ERDA/2521/
Keywords:
ddc:538.7
;
cosmogenic isotopes
;
production rates
;
geomagnetic field
;
geomagnetic excursions
;
Laschamps event
Language:
English
Type:
doc-type:article
