Stratigraphic and geochemical expression of Barremian–Aptian global climate change in Arctic Svalbard

Abstract

Significant changes in global climate and carbon cycling occurred during the Early Cretaceous. This study examines the expression of such climatic events in high-latitude Svalbard together with the stratigraphic utility of carbon-isotope stratigraphies. Isotopic analysis of fossil wood fragments (from the Rurikfjellet, Helvetiafjellet, and Carolinefjellet formations, Festningen, Spitsbergen) record a distinctive pattern including a negative isotope excursion preceding a positive event, correlatable with the global early Aptian isotope event. Our carbon-isotope profile improves the stratigraphic correlation and relative dating of the succession. We show that the upper part of the Helvetia fjellet Formation was deposited during the early Aptian, and not the late Barremian, as previously thought. Furthermore, we estimate an age for the abrupt contact of the Rurikfjellet Formation with the overlying Helvetiafjellet Formation (associated with a pulse of igneous activity) to be ca. 129 Ma or ca. 124 Ma, depending on which age model for the Early Cretaceous is used. The well-known dinosaur footprints of the Helvetiafjellet Formation at Fest ningen are constrained to the middle Barremian and, coupled with floral data, support a warm late Barremian prior to the Aptian carbon-isotope event. The appearance of glendonites at 655 m in the Carolinefjellet Formation is consistent with global cooling in the late Aptian-early Albian.

Dinocyst stratigraphy of the Valanginian–Aptian Rurikfjellet and Helvetiafjellet formations on Spitsbergen, Arctic Norway

“…Our age assignment of the Helvetiafjellet Formation is in agreement with a recent stable carbon isotope (δ 13 C) stratigraphic study of the Festningen outcrop section (Vickers et al 2016). These authors interpreted that the Helvetiafjellet Formation is of Barremian to earliest Aptian age.…”

“…Nevertheless, the existing studies (e.g. Corfu et al 2013;Midtkandal et al 2016;Vickers et al 2016) collectively agree that the Helvetiafjellet Formation is of Barremianearly Aptian age.…”

“…The most widely recognized is the OAE1a, which occurred during the earliest Aptian (Leckie et al 2002;Jenkyns, 2010;Herrle et al 2015;Midtkandal et al 2016). The characteristic stable carbon isotope (δ 13 C) excursions related to OAEs can be used for the correlation of carbon isotope records (Herrle et al 2015;Midtkandal et al 2016;Vickers et al 2016). However, while the climatic history of the Tethys (e.g.…”

Sylfjellet: a new outcrop of the Paleogene Van Mijenfjorden Group in Svalbard

“…The height difference between these coals of same stratigraphic level is c. 600 m across a horizontal distance of only 9 km. [12,23,39,72,73,78,84,90,92] and this study. Stratigraphic chart after [99].…”

“…The outcropping strata cover an area of 0.8 km 2 , and the maximum extent is 1.8 km × 0.7 km. The Sylfjellet succession overlies the c. 25 m-thick cliff-forming sandstones of the Lower (Barremian to Aptian) Festningen Member of the Helvetiafjellet Formation [71][72][73][74][75]. Based on distinct sedimentological and lithological differences, the Sylfjellet succession was subdivided into four units including a coal-bearing unit at the base (Unit 1) overlain by a sandstone-dominated section (Unit 2), which is overlain by dark siltstones (Unit 3), and sandstones on the top (Unit 4).…”