Cosmogenic isotope surface exposure dating dating usa for indians
As described, DO events cannot take place during the Holocene.It is too warm, there is too little ice, and sea level is too high.New DO events will have to wait until the next glacial period.However, the trigger clock is ticking all the time to keep its pace, and it is fair to ask if it might have other effects that could cause a 1500-year climate cycle during the Holocene.This oceanic sedimentary pattern from the glacial period became known as the “Bond cycle.” Since 1996 researchers started to report a 1500-year periodicity in Holocene proxies, and it became Bond’s goal to extend his cycle to the Holocene.He claimed to have achieved that in 2001 when he reported his famous drift-ice petrological record that revealed a series of cold events in the Holocene (Bond et al., 2001; figure 48).The next question is where to look for the 1500-year cycle. The ~ 1500-year periodicity during the Holocene For the last 20 years researchers have been reporting a ~ 1500-year periodicity in Holocene climate proxies. The sea subsurface temperature proxy displays a very clear 1500-year cycle in phase with the DO cycle, where for the past 7000 years higher temperatures at the thermocline took place at the times determined by the DO periodicity (figure 71 b).
The result has been more confusion in the scientific literature and some claims that the 1500-year cycle was perhaps of solar origin. b) Sediment grain size as a proxy for ocean current intensity. d) Sodium flux in GISP2 ice core, a proxy for atmospheric circulation. The authors conclude from the wavelet analysis that the Holocene millennial variability is composed of three main periodicities, 1000, 1500, and 2500-year cycles. And again, we find a period between 9-8,000 years BP when the record displays a 180° phase shift (figure 71 d, black bar).
Researchers all over the world have tried to match negative temperature anomalies and even precipitation fluctuations in their proxy records to Bond events, perpetuating the myth.
As the evidence is contradictory among reports, the existence of a 1500-yr cycle in the Holocene has become more contentious with time. (2011) concluded that Could Bond be wrong, Wanner be right, and still there be a manifestation of the 1500-yr DO cycle in the Holocene?
Bond’s report sparked a paradigm shift because at the time the Holocene was generally viewed as climatically stable, despite contrary evidence from glacier studies.
We have seen that Bond was wrong (figure 48), and his misleading numbering of the cold events to try to fit them into a 1500-year series has caused unnecessary confusion in the field.
In fact, it has been shown that during the Neoglacial the Bond series can be better fitted to a 1500-year periodicity (Debret et al., 2007; figure 48). Occurrence of the periods with respect to the time is given by the bright yellow-red colors. The effect of the DO cycle on thermocline water temperatures was already reviewed in the DO cycle article (see figure 29; Dokken et al., 2013), and was one of the arguments used to support its possible tidal nature.