Anchoring historical sequences using a new source of astro-chronological tie-points

Abstract

The discovery of past spikes in atmospheric radiocarbon activity, caused by major solar energetic particle events, has opened up new possibilities for high-precision chronometry. The two spikes, or Miyake Events, have now been widely identified in tree-rings that grew in the years 775 and 994 CE. Furthermore, all other plant material that grew in these years would also have incorporated the anomalously high concentrations of radiocarbon. Crucially, some plant-based artefacts, such as papyrus documents, timber beams and linen garments, can also be allocated to specific positions within long, currently unfixed, historical sequences. Thus, Miyake Events represent a new source of tie-points that could provide the means for anchoring early chronologies to the absolute timescale. Here, we explore this possibility, outlining the most expeditious approaches, the current challenges and obstacles, and how they might best be overcome.

Absolute tree-ring dates for the Late Bronze Age eruptions of Aniakchak and Thera in light of a proposed revision of ice-core chronologies

“…As noted earlier, Adolphi and Muscheler (2016), using a similar radiocarbon-beryllium 10 linkage but at lower resolution, proposed that the GICC05 ice chronology for the seventeenth century BC was too old by 20±5 years. Dee and Pope (2016) have suggested a possible Miyake event in 1677 BC, which, if correct, could be exploited in both ice-core and tree-ring research relevant to the Thera debate (an optimistic hope being a measurable signature of excess radiocarbon in one of the 72 rings of the Theran olive branch). A Miyake event in 1677 BC may also permit the absolute dating of the Anatolian tree-ring chronology—in particular the Porsuk and Gordion site chronologies—and thus give a precise calendar date for the Porsuk growth anomaly.…”

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

“…A prominent example is the Egyptian chronology, which is characterized by small relative uncertainties and large uncertainties associated with the absolute timing of events that exceed 50 years [Kitchen, 1991]. These events are referred to as cosmic ray events or so-called Miyake events [Dee and Pope, 2016], and they are characterized by an increase in atmospheric Δ 14 C of 10‰ or more within a year. Miyake et al [2012Miyake et al [ , 2013Miyake et al [ , 2014a recently discovered two rapid increases in the 14 C/ 12 C ratio in Japanese cedar and hinoki cypress tree rings that took place in 775 C.E.…”

“…One approach to fix such floating chronologies on an absolute time scale is through the identification of distinct cosmic ray events. This abruptness represents a distinct feature that characterize such cosmic ray events, and the identification of such an event may therefore help anchor floating chronologies [Dee and Pope, 2016]. and 994 C.E.…”

“…These events are referred to as cosmic ray events or so-called Miyake events [Dee and Pope, 2016], and they are characterized by an increase in atmospheric Δ 14 C of 10‰ or more within a year. This abruptness represents a distinct feature that characterize such cosmic ray events, and the identification of such an event may therefore help anchor floating chronologies [Dee and Pope, 2016]. Wacker [2014] thus used the 775 C.E.…”

Multi-proxy dating of Iceland’s major pre-settlement Katla eruption to 822–823 CE

“…From the serendipitous discovery of subfossil trees on Iceland, this study encourages the search for more such material buried under tephra beds and jökulhlaup sediments. More relict wood will contribute to the precise calendar dating of additional Icelandic eruptions, as well as archaeo logical sites (Dee and Pope, 2016). Combined with current modeling efforts, we expect these results to generate mutual benefits at the interface of synchronized and extended model and proxy comparisons, and further disentangle the complicated ties between environmental changes and historical events triggered by volcanism.…”