Cosmic ray event in 994 C.E. recorded in radiocarbon from Danish oak

TY - JOUR

T1 - Cosmic ray event in 994 C.E. recorded in radiocarbon from Danish oak

AU - Fogtmann-Schulz, A.

AU - Østbø, S. M.

AU - Nielsen, Sabrina G. B.

AU - Olsen, J.

AU - Karoff, C.

AU - Knudsen, M. F.

PY - 2017/8/28

Y1 - 2017/8/28

N2 - We present measurements of radiocarbon in annual tree rings from the time period 980-1006 Common Era (C.E.), hereby covering the cosmic ray event in 994 C.E. The new radiocarbon record from Danish oak is based on both earlywood and latewood fractions of the tree rings, which makes it possible to study seasonal variations in 14C production. The measurements show a rapid increase of ∼10‰ from 993 to 994 C.E. in latewood, followed by a modest decline and relatively high values over the ensuing ∼10 years. This rapid increase occurs from 994 to 995 C.E. in earlywood, suggesting that the cosmic ray event most likely occurred during the period between April and June 994 C.E. Our new record from Danish oak shows strong agreement with existing Δ14C records from Japan, thus supporting the hypothesis that the 994 C.E. cosmic ray event was uniform throughout the Northern Hemisphere and therefore can be used as an astrochronological tie point to anchor floating chronologies of ancient history.

AB - We present measurements of radiocarbon in annual tree rings from the time period 980-1006 Common Era (C.E.), hereby covering the cosmic ray event in 994 C.E. The new radiocarbon record from Danish oak is based on both earlywood and latewood fractions of the tree rings, which makes it possible to study seasonal variations in 14C production. The measurements show a rapid increase of ∼10‰ from 993 to 994 C.E. in latewood, followed by a modest decline and relatively high values over the ensuing ∼10 years. This rapid increase occurs from 994 to 995 C.E. in earlywood, suggesting that the cosmic ray event most likely occurred during the period between April and June 994 C.E. Our new record from Danish oak shows strong agreement with existing Δ14C records from Japan, thus supporting the hypothesis that the 994 C.E. cosmic ray event was uniform throughout the Northern Hemisphere and therefore can be used as an astrochronological tie point to anchor floating chronologies of ancient history.

KW - radiocarbon

KW - tree rings

KW - Miyake event

KW - astrochronology

KW - solar proton event

KW - space environment

KW - TREE-RINGS

KW - AD 774-775

KW - CELLULOSE PREPARATION

KW - ISOTOPE ANALYSIS

KW - C-14 PRODUCTION

KW - NEW-ZEALAND

KW - INCREASE

KW - WOOD

KW - CHRONOLOGY

U2 - 10.1002/2017GL074208

DO - 10.1002/2017GL074208

M3 - Journal article

AN - SCOPUS:85028330701

SN - 0094-8276

VL - 44

SP - 8621

EP - 8628

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 16

ER -