Late Triassic paleowinds from lacustrine wave ripple marks in the Fleming Fjord Group, central East Greenland

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Geological evidence of paleoclimate conditions provide important constraints on paleoclimate models. Paleowinds are one of the central paleoclimate parameters in global circulation models used to reconstruct past climatic conditions. However, only a few climate proxies such as eolian dunes and shallow-water wave ripples provide information on paleowind directions. In this study, we present new paleoclimatic data based on lacustrine sediments with wave ripple marks in the Upper Triassic Fleming Fjord Group, central East Greenland deposited at very shallow water depth in the northern part of Pangaea in a mid-latitude, warm-temperate climate. Wave-ripple orientations are measured on 380 individual fossilized wave-rippled beds at four localities in the ~8500 km2 lacustrine basin. These ripple data are used to establish a geologic wind proxy and are compared to previously published general circulation models. Two wave ripple orientations are observed: The dominant ripple orientation and wave ripple characteristics indicate paleowinds from the Late Triassic SSE and NNW (154.5° and 334.5°), while a subordinate orientation indicate paleowinds from W or E (270° or 90°). This paleowind regime remained stable for at least ~7.5 million years during the mid-late Norian (218.5-211 Ma). These results correspond very well with some general circulation model results that suggest summer winds from the NNW and winter winds from the SSE. Based on the great compatibility between empirical data and general circulation model results, the wind pattern seems to have been greatly influenced by regional, Late Triassic mountain topography in the present-day Greenland and Norway channeling the paleowind in the northernmost part of the pre-Atlantic rift basin (the mid-Norwegian-east Greenland rift system).

OriginalsprogEngelsk
Artikelnummer110776
TidsskriftPalaeogeography, Palaeoclimatology, Palaeoecology
Vol/bind586
Antal sider11
ISSN0031-0182
DOI
StatusUdgivet - 2022

Bibliografisk note

Funding Information:
We thank the Independent Research Fund Denmark , the Carlsberg Foundation and Geocenter Møns Klint for funding this project and the Geologic Survey of Denmark and Greenland for logistical help in the field. The authors would like to thank the Bristol Research Initiative for the Dynamic Global Environment (BRIDGE), Alexander Farnsworth and Paul Valdes for making their model simulations available for further analysis. We would also like to thank Bo Markussen (Department of Mathematical Sciences at the University of Copenhagen) for guidance about statistical analyses. Thanks to Stéphane Pochat and an anonymous referee for constructive reviews.

Funding Information:
We thank the Independent Research Fund Denmark, the Carlsberg Foundation and Geocenter M?ns Klint for funding this project and the Geologic Survey of Denmark and Greenland for logistical help in the field. The authors would like to thank the Bristol Research Initiative for the Dynamic Global Environment (BRIDGE), Alexander Farnsworth and Paul Valdes for making their model simulations available for further analysis. We would also like to thank Bo Markussen (Department of Mathematical Sciences at the University of Copenhagen) for guidance about statistical analyses. Thanks to St?phane Pochat and an anonymous referee for constructive reviews.

Publisher Copyright:
© 2021 The Authors

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