Fig. 1: Stratigraphic context of the Mochras borehole in the Upper Pliensbachian (934–951 mbs), Margaritatus Zone, Subnodosus-Gibbosus subzones.

a The Mochras borehole has been cyclostratigraphical tuned based on two independent geochemical time series, elemental Ca record^43,45 and δ¹³C_org⁴⁶. The sampled interval for this study shows strong orbital forcing⁴³ and is within the stable part of the δ¹³C_org record⁴⁶, allowing examination of climatic background fluctuations and the effects of Milankovitch cycles on the charcoal record. b The Mochras borehole was located at a palaeo-latitude of ~35°N⁸⁵, within the Laurasian Seaway^86,87 south of the Viking Corridor that linked the NW Tethys Ocean to the Boreal Sea⁸⁸. Reprinted from ref. ⁴³. Copyright (2021) with permission from Elsevier. c Detail of the filtered orbital periodicities in the Pliensbachian carbonate record⁴³ are plotted next to data from this study, and span approximately 350 kyr^43,45. Clear alternations of carbonate-rich and TOC-enhanced lithological couplets are observed at a metre scale, which are forced by precession⁴³. Finally, high resolution δ¹³C_org data confirms that the 934–951 mbs interval contains only a minor swing of ~0.5‰.