Contrasting Hydroclimate Response of Coastal Norway and Arctic Russia During Late-Glacial and Holocene Climate Change
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Reconstructing changes to the δ2H of precipitation through time as recorded in leaf wax hydrogen isotopes (δ2Hwax) can provide substantive information about changes to local hydroclimate, incorporating influences from the moisture source region, the transport history of atmospheric water vapor, and local conditions during precipitation. Lake sediment δ2Hwax thus has the potential to record detailed information about local hydroclimate at high spatial and temporal resolution. I present the results of two independent δ2Hwax reconstructions, one from a modern peat bog on the southwest coast of Norway called Kringlemyr, and the other from Bolshoye Schuchye, a large lake in the Polar Ural Mountains. The Kringlemyr record spans 16 to 11.5 ka at approximately 100-year resolution, while the Bolshoye Schuchye record spans 23.2 to 1.1 ka at approximately 500-year resolution. At Kringlemyr, there is a strong response of δ2Hwax to the hydroclimate shifts that occur during the late-glacial, including the transition from Heinrich Stadial I to the Bølling, as well as the transitions into and out of the Younger Dryas. These transitions in δ2Hwax consistently lead changes in local pollen assemblages as well as Greenland temperatures by hundreds of years, most likely reflecting early intensification of AMOC prior to local temperature shifts. Our record also shows changes to temperature and snowfall amounts that help explain the behavior of local glaciers and the western margin of the Fennoscandian Ice Sheet during the late-glacial. The record from Bolshoye Schuchye is more difficult to interpret in detail, due to the scarcity of independent proxy data from Arctic Russia. The interesting features of the δ2Hwax record at Bolshoye Schuchye are the magnitude of the transition moving into the Holocene, which likely reflects a combination of warming and atmospheric reorganization, contrasted with the lack of response to pre-Holocene climatic oscillations. Combined, these two δ2Hwax records demonstrate the geographically variable response of hydroclimate to abrupt temperature shifts, which seems to be particularly dependent on the position of each site relative to the Fennoscandian Ice sheet and the prevailing westerlies. The contrast in changes observed prior to the Holocene in coastal Norway and Arctic Russia emphasizes that changes found in the North Atlantic region are not necessarily representative of the entire Northern Hemisphere during the late-glacial.