Latitudinal migration of calcareous nannofossil Micula murus in the Maastrichtian: Implications for global climate change

Abstract

Micula murus is one of the main calcareous nannofossil biostratigrapic markers of Tethyan and Intermediate provinces in the upper Maastrichtian (uppermost Cretaceous). A review of its fi rst occurrence at 14 deep-sea sites and sections shows that it is time transgressive from the Tropical Realm of the Atlantic and Pacifi c Oceans to the intermediate latitudes of the North Atlantic, South Atlantic, Indian Ocean, and the northern Tethys. M. murus remained confi ned to the Tropical Realm for ~1.2 m.y. in the early-late Maastrichtian, thus supporting high-latitudinal thermal gradients. It subsequently spread out in the late Maastrichtian to temperate latitudes and to the Tethys in coincidence with the onset of a thermohaline circulation change ca. 67.5 Ma, suggesting a major change in surface-water circulation and interocean communications.

Biogeochemical significance of pelagic ecosystem function: an end-Cretaceous case study

“…Increased burial of carbonate on shelves to compensate for less deep-ocean burial could have played a role [67] (see also electronic supplementary material, figure S9), although evidence for such an increase is, at best, scant (see electronic supplementary material, Discussion). [25,26,52], dwarfing of some planktonic foraminiferal species [73] and regional assemblage changes [74], but there was no elevation in extinction rates of functionally important marine calcifier species (planktonic foraminifera and coccolithophores) at this time [69,75]. This retention of biodiversity and redundancy among calcifiers, we suggest, was probably important in maintaining the resilience of the pelagic ecosystem (and its associated biogeochemical functions) [15,76].…”

“…Another possible explanation is that Deccan-induced warming resulted in a more stratified ocean with more oligotrophic surface waters [26,52,53]. In the modern ocean, oligotrophy favours ecosystems more heavily dominated by coccolithophore production when compared with siliceous and organic-walled primary producers [70].…”

“…95% and 90% in planktonic foraminifera and calcareous nannofossils, respectively [23,24]). In contrast, during Late Cretaceous Deccan trap volcanism, biotic disturbance in the open ocean was largely limited to changes in biogeographic ranges [25,26]. Together, these events allow us to contrast the impact of environmental changes on ecosystem function with and without associated loss of pelagic biodiversity.…”

Data report: revised age models for IODP Sites U1480 and U1481, Expedition 362

“…The oldest sediment investigated (Sample 362-U1480G-71R-2, 97 cm; 1414.31 mbsf ), located 1.04 m above the basaltic basement at 1415.35 mbsf, contains late Maastrichtian calcareous nannofossils including Micula murus (Tie Point Ma2). This species is known to be time transgressive, appearing later (67.33 Ma) at intermediate latitudes in the North and South Atlantic, Indian Ocean, and northern Tethys (Thibault et al, 2010;, and implies an oldest possi- gives an age of 58.1 Ma for the onset of the hiatus, which therefore occupies 62% of the duration of the Cenozoic era. Four calcareous nannofossil and seven radiolarian markers from Sample 61R-5, 13-14 cm (1323.49 mbsf ), to Sample 58R-1, 106-107 cm (1289.67 mbsf ), observed ~3-37 m above the hiatus do not fit the proposed age model.…”

An astronomical time scale for the Maastrichtian based on the Zumaia and Sopelana sections (Basque country, northern Spain)

“…Nevertheless, it is likely that these discrepancies are partly the result of true migration patterns across latitudes and different oceanic basins, controlled by the high climate variability of the late Campanian-Maastrichtian interval. Strongly diachronic succession and ages of late Campanian-Maastrichtian calcareous plankton bio-horizons have already been interpreted as the expression of climatically induced migration patterns between Tethyan, Transitional and Austral provinces (Huber and Watkins 1992;Nifuku et al 2009;Thibault et al 2010;Thibault et al 2012a). This potential mechanism must be acknowledged, thoroughly assessed and quantified in the Late Cretaceous because many studies use calcareous plankton biochronology to build their age-models.…”