Ice-rafted dropstones at midlatitudes in the Cretaceous of continental Iberia

• Main Authors: Juan Pedro Rodríguez-López, Carlos L Liesa, Aránzazu Luzón, Arsenio Muñoz, María J Mayayo, Julian Murton, Ana R Soria
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2024
• Subjects: Earth sciences; Geology; Physical geography and environmental geoscience; 37 Earth Sciences; 3709 Physical Geography and Environmental Geoscience; 3705 Geology; 04 Earth Sciences; Geochemistry & Geophysics; Arctic; Canada; glacier*; Ice; Ice Sheet; Iceberg*; permafrost
• Online Access: https://figshare.com/articles/journal_contribution/Ice-rafted_dropstones_at_midlatitudes_in_the_Cretaceous_of_continental_Iberia/25020440

The Cretaceous is widely considered to have been a period subjected to super-greenhouse conditions. Here, we provide multiscale sedimentologic evidence of glaciers developing at mid-paleolatitudes (~45°N) in continental Iberia during the Hauterivian cold snap. Striated and faceted ice-rafted glacial dropstones (cobble to boulder size) and striated and grooved silt- to sand-sized grains (ice-rafted debris [IRD]) occur in a lacustrine sequence of the Enciso Group in the eastern Cameros Basin, Spain. The ice-rafted materials constitute the first evidence reported for a Cretaceous continental cryospheric record in Europe, and they are attributed to calving of glacier snouts, releasing icebergs into an ice-contact lake. The sedimentary succession resembles glacial-deglacial records in lakes overridden by the late Pleistocene Laurentide Ice Sheet in eastern Arctic Canada. The Iberian glacial succession was coeval with plateau permafrost in Asia and IRD records in the Arctic and Australia, revealing a stronger than previously thought cryosphere during the global Hauterivian cold snap.