The Jurassic-Cretaceous boundary: An age-old correlative enigma

Abstract

The Jurassic-Cretaceous boundary interval has been problematic since the start of stratigraphic study. This is reflected in different stage names being employed in Boreal and Tethyan realms below and above the putative boundary. Despite attempts at homogenisation where stage terminology is concerned, correlative precision over long distances at or close to a boundary has not yet been achieved. But the new Berriasian/ J-K boundary working-group of the Cretaceous Subcommission is now attempting to remedy this situation.

LicenseCalpionellid biostratigraphy and sedimentation of the Biancone limestone from the Rudnica Anticline (Sava Folds, eastern Slovenia)

“…Calpionellids are an example of such group, owing to their uniform occurrence and diversification; as a result they are widely used in biostratigraphic analyses of the Late Jurassic and Early Cretaceous pelagic sequences throughout the Tethyan Realm (Allemann et al, 1971;Remane, 1971;Remane et al, 1986;Pop, 1974Pop, , 1994Reháková & Michalík, 1997;Lakova, et al, 1999;Boughdiri et al, 2006;Houša et al, 2007). From the point of view of calpionellid biostratigraphic potential, we note that alongside Calpionellites darderi, the index marker for the Berriasian/Valanginian stage boundary (Bulot, 1996), Calpionella alpina is considered to be most useful marker for determination of the Jurassic/Cretaceous boundary (Andreini et al, 2007;Houša et al, 2007;Wimbledon, 2008;Michalík et al, 2009;Grabowski et al, 2010a,b;Lukeneder et al, 2010;Pruner et al, 2010;Michalík & Reháková, 2011;Petrova et al, 2012;Guzhikov et al, 2012;Lakova & Petrova, 2013;López-Martínez et al, 2013, 2015Wimbledon et al, 2013Wimbledon et al, , 2017Hoedemaeker et al, 2016;Michalík et al, 2016;Svobodová & Košťák, 2016;Grabowski et al, 2017;Elbra et al, 2018 a,b;Kowal-Kasprzyk & Reháková, 2019).…”

Early Cretaceous stratigraphy and SHRIMP U-Pb age constrain the Valanginian–Hauterivian boundary in southern Tibet

“…One reason for the debate has been the biogeographic variation of ammonites between the Tethyan and Boreal provinces (Jeletzky 1984; Hoedemaeker 1991; Podobina & Tatyanin 2000, among many others). According to general agreement the Berriasian Stage is the basal stage of the Cretaceous System and the first appearance of Berriasiella jacobi defines the base of the Berriasian (Hoedemaeker 1987; Wimbledon 2008). The currently accepted numerical age of the base of the Berriasian is 145.5 Ma (Gradstein et al.…”

Berriasian ammonites of supposed Tethyan origin from the type ‘Ryazanian’, Russia: a systematic re-interpretation

“…Provincialism is also marked within the realms since, for example, Arctic, Boreal-Atlantic and Boreal-Pacific subrealms have been distinguished in the 'Boreal Realm' at that time (Lehmann et al, 2015 and references therein). This severe biological restriction has for generations prevented substantial progress in long-distance correlation (Wimbledon, 2008), and strongly influenced the use of regional stage names for these deposits (e.g., "Purbeckian", "Portlandian", "Volgian", and 'Ryazanian' for the boreal/sub-boreal regions and beyond) even after the ratification of the Tithonian and Berriasian as the global stages for the uppermost Jurassic and lowermost Cretaceous, respectively (Sarjeant and Wimbledon, 2000;Cope, 2007Cope, , 2013Wimbledon, 2008;Wimbledon et al, 2011). Although the formal selection of a GSSP (Global Boundary Stratotype Section and Point) for the Berriasian is pending, the incoming of small, globular forms of Calpionella alpina and the sharp decline in abundance of Crassicollaria calpionellid species, which together define the base of the Calpionella Zone, have been formally selected as primary boundary markers for the base of the stage (with supporting nannofossils, calcareous dinoflagellates, ammonites, and magnetostratigraphy) (Wimbledon, 2017;Wimbledon et al, 2020).…”