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New insights into the thermal regime and hydrodynamics of the early Late Cretaceous Arctic

Spicer, Robert; Valdes, Paul; Hughes, Alice; Yang, Jian; Spicer, Teresa; Herman, Alexei and Farnsworth, Alexander (2019). New insights into the thermal regime and hydrodynamics of the early Late Cretaceous Arctic. Geological Magazine (Early Access).

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The Arctic is warming faster than anywhere else of comparable size on Earth, impacting global climate feedbacks and the Arctic biota. However, a warm Arctic is not novel. The Late Cretaceous fossil record of the region enables a detailed reconstruction of polar environmental conditions, and a thriving extinct ecosystem, during a previous 'hothouse’ global climate. Using leaf form (physiognomy) and tree ring characteristics we reconstruct Cenomanian to Coniacian polar thermal and hydrological regimes over an average annual cycle at eight locations in NE Russia and northern Alaska. A new high spatial resolution (∼1 km) WorldClim2 calibration of the Climate Leaf Analysis Multivariate Program (CLAMP) yields results similar to, but often slightly warmer than, previous analyses, but also provides more detailed insights into the hydrological regime through the return of annual and seasonal vapour pressure deficit (VPD), potential evapotranspiration (PET) estimates and soil moisture, as well as new thermal overviews through measures of thermicity and growing degree days. The new results confirm the overall warmth of the region, particularly close to the Arctic Ocean, but reveal strong local differences that may be related to palaeoelevation in the Okhotsk–Chukotka Volcanogenic Belt in NE Russia. While rainfall estimates have large uncertainties due to year-round wet soils in most locations, new measures of VPD and PET show persistent high humidity, but with notably drier summers at all the Arctic sites.

Item Type: Journal Item
Copyright Holders: 2019 Cambridge University Press
ISSN: 0016-7568
Project Funding Details:
Funded Project NameProject IDFunding Body
Xishuangbanna Tropical Botanical Garden (XTBG) International Fellowship for Visiting ScientistsNot SetChinese Academy of Sciences
Keywords: polar warmth; palaeoclimate; CLAMP; ecosystem; Alaska; Russia; plant fossils
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Environment, Earth and Ecosystem Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 61981
Depositing User: ORO Import
Date Deposited: 19 Jun 2019 09:22
Last Modified: 18 Nov 2019 15:40
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