North Atlantic Ocean Research Papers (original) (raw)

"In the northern North Atlantic, the 4.2 ka BP event is evident in lake, bog, marine, glacial, speleothem and tree ring cores with extensive, coherent, and high resolution proxy data for abrupt century-scale alterations of temperature and precipitation. These records extend across the northern North Atlantic, 1900 kms northeast to southwest, from Spitzbergen, Svalbard to Agassiz Ice Cap, Ellesmere Island, including Sweden, Norway, Denmark, Faroe Islands, Iceland and adjacent seas, and Greenland. Adjacent region, high resolution proxy data in Europe and North America provide synchronous and similar records. The proposed article by Bradley and Bakke (cp-2018-162, in review), however, ignores the relevant data from Svalbard, Sweden, Norway, Denmark, Faroe Islands, Iceland, Nordic Seas, Greenland and Ellesmere Island.

In Figure 1, a) - b) are Greenland Ice Sheet Total mass balance and ice volume experiments 5 and 6 from Nielsen et al., 2017 that present an abrupt ca 200 year warming event beginning at ca 4.3 ka BP. This melt spike is synchronous with c), the modeled 4 degree SST cooling spike in the Northwest Atlantic, ca. 4.3-4.1 ka BP (Klus et al., 2017) and with the abrupt NGRIP ca. 5 degree K warm spike ca. 4.5-3.9 ka BP (Gkinis et al, 2014). In d), the Agassiz, Ellesmere Island and Renland, Greenland ice core temperature spike is 3-stage, beginning at 4290 BP, reaching its apogee at 4150 BP, returning to baseline at 3990 BP, and descending to pre-event levels at 3790 BP (Vinther et al., 2009). The sudden GISP2, Greenland temperature spike (Kobashi et al, 2017), although less well-defined, conforms to this event. These six key North Atlantic high resolution and modeled data are summarized in e), which presents the remarkable congruence of the Lake Hajeren, Svalbard, sediment core and the Agassiz, Ellesmere Island ice core. The Lake Hajeren neo-glaciation spike, recognized in minerogenic / glacigenic indicators TDBD (dry bulk density) and Ti/Loss on Ignition z-scores from core HAP0212, extends from ca. 4250 BP to ca. 4100/4050 BP, a calibrated radiocarbon interpolation across two hundred years (van der Bilt et al., 2015). The synchronous Agassiz ice core melt spike extends from ca. 4250 – 3950 BP, with an error of ca. 20 years (Fisher et al., 2012; Lecavalier et al., 2017).

In summary, the Lake Hajeren, Spitsbergen, Svalbard cold glaciation event was synchronous with the Ellesmere Island Agassiz ice core warm melt event 1900 kms distant across the span of Iceland and adjacent seas and Greenland. The same relationship obtains with the NGRIP warm event (Gkinis et al., 2014) and the modeled Northwest Atlantic Sea Surface Temperature event (Klus et al., 2018): in the northern North Atlantic, cold lake and sea events were synchronous with warm, elevation-corrected, glacier events that extend as far west as Mount Logan, Yukon (Fisher et al., 2012). This curious, highly resolved, 4.2 ka BP event situation has not been discussed previously and there exist neither proximate nor ultimate explanations for it."