Climate variability and long-term expansion of peatlands in Arctic Norway during the late Pliocene (ODP Site 642, Norwegian Sea)

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doi: 10.5194/cp-12-1043-2016
Author(s): Panitz, Sina; Salzmann, Ulrich; Risebrobakken, Bjorg; De Schepper, Stijn; Pound, Matthew J.
Author Affiliation(s): Primary:
Northumbria University, Department of Geography, Newcastle upon Tyne, United Kingdom
Other:
Bjerknes Centre for Climate Research, Norway
Volume Title: Climate of the Past
Source: Climate of the Past, 12(4), p.1043-1060. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. 96 refs.; illus., incl. 1 table, sketch maps
Summary: Little is known about the terrestrial response of high-latitude Scandinavian vegetation to the warmer-than-present climate of the late Pliocene (Piacenzian, 3.60-2.58 Ma). In order to assess Piacenzian terrestrial climate variability, we present the first high-resolution reconstruction of vegetation and climate change in northern Norway between 3.6 and 3.14 Ma. The reconstructions are derived from pollen assemblages in the marine sediments of ODP Hole 642B, Norwegian Sea (67° N). The palynological assemblages provide a unique record of latitudinal and altitudinal shifting of the forest boundaries, with vegetation alternating between cool temperate forest during warmer-than-present intervals and boreal forest similar to today during cooler intervals. The northern boundary of the nemoral to boreonemoral forest zone was displaced at least 4-8° further north, and warmest-month temperatures were 6-14.5 °C higher than at present during warm phases. Warm climatic conditions persisted during the earliest Piacenzian (ca. 3.6-3.47 Ma) with diverse cool temperate nemoral to boreonemoral forests growing in the lowlands of the Scandinavian mountains. A distinct cooling event at ca. 3.47 Ma resulted in a southward shift of vegetation zones, leading to the predominance of boreal forest and the development of open, low alpine environments. The cooling culminated around 3.3 Ma, coinciding with Marine Isotope Stage (MIS) M2. Warmer climate conditions returned after ca. 3.29 Ma, with higher climate variability indicated by the repeated expansion of forests and peatlands during warmer and cooler periods, respectively. Climate progressively cooled after 3.18 Ma, resembling climatic conditions during MIS M2. A high variability of Norwegian vegetation and climate changes during the Piacenzian is superimposed on a long-term cooling trend. This cooling was accompanied by an expansion of Sphagnum peatlands that potentially contributed to the decline in atmospheric CO2 concentrations at the end of the Piacenzian warm period and facilitated ice growth through positive vegetation-snow albedo feedbacks. Correlations with other Northern Hemisphere vegetation records suggest hemisphere-wide effects of climate cooling.
Year of Publication: 2016
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Age; Alpine environment; Arctic Ocean; Arctic region; Assemblages; Biozones; Boreal environment; Cenozoic; Climate; Climate change; Climate effects; Cooling; Correlation; Europe; Feedback; Fluctuations; Forests; Glaciation; Holocene; Land cover; Leg 104; Marine sediments; Microfossils; Miospores; Mires; Models; Modern; Neogene; Norway; Norwegian Sea; ODP Site 642; Ocean Drilling Program; Paleoclimatology; Paleoenvironment; Palynomorphs; Peatlands; Piacenzian; Pliocene; Pollen; Pollen analysis; Pollen diagrams; Quantitative analysis; Quaternary; Reconstruction; Sample preparation; Scandinavia; Sediments; Subarctic regions; Temperate environment; Temperature; Temporal distribution; Terrestrial environment; Tertiary; Tree line; Upper Holocene; Upper Pliocene; Vegetation; Voring Plateau; Western Europe
Coordinates: N671312 N671330 E0025548 E0025542
Record ID: 2017017654
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Copernicus Gesellschaft, Katlenburg-Lindau, Germany