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Multiradionuclide evidence for an extreme solar proton event around 2610 BP

Ohare, Martin Paschal LU (2017) In Dissertations in Geology at Lund University GEOR02 20171
Department of Geology
Abstract
Recently it has been confirmed that extreme solar proton events (SPE) can lead to significantly increased production of cosmogenic radionuclides (Mekhaldi et al. 2015). The evidence of these events can be recorded in tree rings (14C) and ice cores (10Be, 36Cl). The IntCal13 calibration curve, which is a continuous tree ring record of 14C fluctuations throughout the Holocene, was used to locate two potential spikes in radionuclide production (~7510 and ~2610 BP). The primary aim of this study was to establish whether these potential spikes have counterparts in other radionuclide records. The secondary aim was to determine whether the spikes in radionuclide production could be attributed to extreme solar events, and to define the parameters... (More)
Recently it has been confirmed that extreme solar proton events (SPE) can lead to significantly increased production of cosmogenic radionuclides (Mekhaldi et al. 2015). The evidence of these events can be recorded in tree rings (14C) and ice cores (10Be, 36Cl). The IntCal13 calibration curve, which is a continuous tree ring record of 14C fluctuations throughout the Holocene, was used to locate two potential spikes in radionuclide production (~7510 and ~2610 BP). The primary aim of this study was to establish whether these potential spikes have counterparts in other radionuclide records. The secondary aim was to determine whether the spikes in radionuclide production could be attributed to extreme solar events, and to define the parameters of these events.
The results indicate an increase in 10Be concentration and flux from the NGRIP ice core for the younger period of interest, 2610 BP. Additionally, a peak in concentration and flux has been discovered in existing GRIP 36Cl records for the same period. This synchronous peak in both records is consistent with the increased radionuclide production expected due to an extreme SPE. Calculations based on the production yields of 10Be and 36Cl suggest that the hypothesised SPE around 2610 BP was characterised by a hard spectrum and a exceptionally high fluence. Furthermore, this event was at least an order of magnitude more energetic than the so far assumed strongest hard SPE of February 1956, and similar in magnitude to the remarkably strong hard AD775 paleo-SPE event. (Less)
Popular Abstract (Swedish)
Det har nyligen bekräftats att extrema solar proton events (SPE) kan leda till kraftigt ökad produktion av kosmogena radionuklider (Mekhaldi et al. 2015). Bevis för detta kan påträffas i trädringar (14C) och iskärnor (10Be, 36Cl). Kalibreringskurvan IntCal13, vilken är ett kontinuerligt trädringsregister över 14C fluktuation- er under hela Holocen, användes för att lokalisera två potentiella toppar i radionuklidproduktion (ca 7510 och ca 2610 BP). Det främsta syftet med denna studie var att fastställa huruvida dessa potentiella toppar har motsvarigheter i andra radionuklida arkiv. Vidare var syftet att fastställa huruvida topparna i radionuklid produk- tion kan hänföras till extrema solar proton events, samt definiera parametrarna för... (More)
Det har nyligen bekräftats att extrema solar proton events (SPE) kan leda till kraftigt ökad produktion av kosmogena radionuklider (Mekhaldi et al. 2015). Bevis för detta kan påträffas i trädringar (14C) och iskärnor (10Be, 36Cl). Kalibreringskurvan IntCal13, vilken är ett kontinuerligt trädringsregister över 14C fluktuation- er under hela Holocen, användes för att lokalisera två potentiella toppar i radionuklidproduktion (ca 7510 och ca 2610 BP). Det främsta syftet med denna studie var att fastställa huruvida dessa potentiella toppar har motsvarigheter i andra radionuklida arkiv. Vidare var syftet att fastställa huruvida topparna i radionuklid produk- tion kan hänföras till extrema solar proton events, samt definiera parametrarna för dessa event.
Resultaten indikerar en ökning av 10Be-koncentration och flöde från NGRIP-iskärnan för den yngre av de stu- derade perioderna, 2610 BP. Dessutom har en topp i koncentration och flöde upptäckts i befintliga GRIP 36Cl arkiv för samma period. Denna synkrona topp i båda geologiska arkiv är överensstämmande med den ökade radi- onuklidproduktion som kan förväntas efter en extrem SPE. Beräkningar baserade på mängden producerad 10Be och 36Cl tyder på att den hypotiserade SPEn runt 2610 BP präglades av ett hårt spektrum och en exceptionellt hög flu- ens. Dessutom var detta event åtminstone en storleksordning starkare än det hittills förmodat starkaste hårda SPE i februari 1956 och i samma storleksordning som det anmärkningsvärt starka hårda AD775 paleo-SPE eventet. (Less)
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author
Ohare, Martin Paschal LU
supervisor
organization
course
GEOR02 20171
year
type
H2 - Master's Degree (Two Years)
subject
keywords
cosmic-rays, cosmogenic radionuclides, NGRIP, GRIP, solar proton event, SPE
publication/series
Dissertations in Geology at Lund University
report number
499
language
English
id
8905472
date added to LUP
2017-04-05 14:22:53
date last changed
2019-04-05 03:45:57
@misc{8905472,
  abstract     = {Recently it has been confirmed that extreme solar proton events (SPE) can lead to significantly increased production of cosmogenic radionuclides (Mekhaldi et al. 2015). The evidence of these events can be recorded in tree rings (14C) and ice cores (10Be, 36Cl). The IntCal13 calibration curve, which is a continuous tree ring record of 14C fluctuations throughout the Holocene, was used to locate two potential spikes in radionuclide production (~7510 and ~2610 BP). The primary aim of this study was to establish whether these potential spikes have counterparts in other radionuclide records. The secondary aim was to determine whether the spikes in radionuclide production could be attributed to extreme solar events, and to define the parameters of these events.
The results indicate an increase in 10Be concentration and flux from the NGRIP ice core for the younger period of interest, 2610 BP. Additionally, a peak in concentration and flux has been discovered in existing GRIP 36Cl records for the same period. This synchronous peak in both records is consistent with the increased radionuclide production expected due to an extreme SPE. Calculations based on the production yields of 10Be and 36Cl suggest that the hypothesised SPE around 2610 BP was characterised by a hard spectrum and a exceptionally high fluence. Furthermore, this event was at least an order of magnitude more energetic than the so far assumed strongest hard SPE of February 1956, and similar in magnitude to the remarkably strong hard AD775 paleo-SPE event.},
  author       = {Ohare, Martin Paschal},
  keyword      = {cosmic-rays,cosmogenic radionuclides,NGRIP,GRIP,solar proton event,SPE},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Multiradionuclide evidence for an extreme solar proton event around 2610 BP},
  year         = {2017},
}