Global climate change and planktic foraminiferal response in the Maastrichtian

Abstract

[1] The lengthy warm, stable climate of the Cretaceous terminated in the Campanian with a cooling trend, interrupted in the early and latest Maastrichtian by two events of global warming, at ∼70-68 Ma and at 65.78-65.57 Ma. These climatic oscillations had a profound effect on pelagic ecosystems, especially on planktic foraminiferal populations. Here we compare biotic responses in the tropical-subtropical (Tethyan) open ocean and mesotrophic (Zin Valley, Israel) and oligotrophic (Tunisia) slopes, which correlate directly with global warming and cooling. The two warming events coincide with blooms of Guembelitria, an extreme opportunist genus best known as the main survivor of the Cretaceous-Paleogene (K-Pg) catastrophe. In the Maastrichtian, Guembelitria bloomed in the uppermost surface water above shelf and slope environments but failed to reach the open ocean as it did at K-Pg. The coldest interval of the late Maastrichtian (∼68-65.78 Ma) is marked by an acme of the otherwise rare species Gansserina gansseri, a deep-dwelling keeled globotruncanid. The G. gansseri acme event can be traced from the deep ocean even onto the Tethyan slope, marking copious production and circulation of cold intermediate water. This acme is abruptly terminated by extinction of the species, a dramatic reversal attributed to a short-term global warming episode. This extinction corresponds precisely with the second bloom of Guembelitria that began ∼300 kyr prior to the K-Pg event. The antithetical relationship between blooming of Guembelitria and the G. gansseri acme reflects planktic foraminiferal sensitivity to warm-cool-warm-cool climatic oscillations marking the end of the Cretaceous.

Atmospheric halogen and acid rains during the main phase of Deccan eruptions: Magnetic and mineral evidence

“…2; Li and Keller, 1998;Stuben et al, 2003;Wilf et al, 2003;Abramovich et al, 2010). We measured carbon and oxygen isotope compositions for the entire section (~6 m) at 20 cm intervals, as well as at higher resolution (5 cm intervals) for the low-MS interval of the top 1 m, with comparable results (Figs.…”

Did Late Cretaceous cooling trigger the Campanian–Maastrichtian Boundary Event?

“…Tercis, France; northern Germany; eastern England: after Jarvis et al 2002, Voigt et al 2010 are plotted using the age-model of Voigt et al (2012); samples older than 79 Ma are interpolated by using the GTS age of the Santonian-Campanian boundary (83. eschweizerbart_xxx This is supported by the observation that the genera Globotruncana, Globotruncanita, and Globotruncanel la, which are usually common in late Campanian deeper-water settings (Abramovich et al 2003, 2010, Pérez-Rodríguez et al 2012, are only represented in Shuqualak Evans by a few specimens each, suggesting conditions were not suitable for all planktonic foraminifera. Thus, it is possible that the stratigraphic range of R. calcarata is shorter in Shuqualak than in other North Atlantic localities due to local conditions.…”

Maastrichtian-Thanetian planktonic foraminiferal biostratigraphy and remarks on the K-Pg boundary in the southern Kocaeli Peninsula (NW Turkey)

“…Very short durations of the CF1 and CF2 zones (~90,000 and ~120,000 years, respectively, based on the revised ages from Abramovich et al (2010)) complicate the diagnosis of these two biozones in the studied sections. Additionally, the top of the Cretaceous sequence coincides with a synsedimentary event in the Belen and Bulduk sections.…”