Enigmatic Late Cretaceous high palaeo-latitude lonestones in Chukotka, northeasternmost Asia

• Published in: GFF
• Main Authors: Ahlberg, Anders, Herman, AB, Raikevich, M, Rees, A, Spicer, RA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis 2002
• Subjects: Geotechnical Engineering; Russia; dropstones; lonestones; Cretaceous; Chukotka
• Online Access: https://lup.lub.lu.se/record/317332; https://doi.org/10.1080/11035890201244197

Well-rounded cobbles were encountered within a low-energy restricted marine organic-rich deposit of latest Cretaceous age in Chukotka, NE Asia. The clasts are hydrodynamically incompatible with the inferred quiet depositional environment of the host sediment. Driftwood capable of tree-rafting, glacial striations, gastrolith clast clustering, and disrupting clast impact impressions typical of volcanic ejecta were absent, as were signs of traction currents. If indeed ice-rafting is responsible, this supports recent climate models and palaeobotanical data which favour seasonal marine ice cover of high northern latitudes over a wide span of boundary conditions.