Contribution of orbital forcing and Deccan volcanism to global climatic and biotic changes across the Cretaceous-Paleogene boundary at Zumaia, Spain

Abstract

Untangling the timing of the environmental effects of Deccan volcanism with respect to the Chicxulub impact is instrumental to fully assessing the contributions of both to climate change over the Cretaceous-Paleogene boundary (KPB) interval. Despite recent improvements in radiometric age calibrations, the accuracy of age constraints and correlations is insufficient to resolve the exact mechanisms leading to environmental and climate change in the 1 m.y. across the KPB. We present new high-resolution planktic foraminiferal, geochemical, and geophysical data from the Zumaia section (Spain), calibrated to an updated orbitally tuned age model. We provide a revised chronology for the major carbon isotope excursions (CIEs) and planktic foraminiferal events and test temporal relationships with different models of the eruptive phases of the Deccan Traps. Our data show that the major CIEs near the KPB, i.e., the late Maastrichtian warming event (66.25–66.10 Ma) and the Dan-C2 event (65.8–65.7 Ma), are synchronous with the last and the first 405 k.y. eccentricity maximum of the Maastrichtian and the Danian, respectively, and that the minor Lower C29n event (65.48–65.41 Ma) is well constrained to a short eccentricity maximum. Conversely, we obtained evidence of abrupt environmental change likely related to Deccan volcanism at ca. 65.9 Ma, based on a bloom of opportunistic triserial guembelitriids (Chiloguembelitria). The orbital, isotopic, and paleobiological temporal relationships with Deccan volcanism established here provide new insights into the role of Deccan volcanism in climate and environmental change in the 1 m.y. across the KPB.

New Biochronological Scales of Planktic Foraminifera for the Early Danian Based on High-Resolution Biostratigraphy

“…The two lower Danian biozonations proposed here are mainly based on the pelagic sections of Caravaca [8,24,[30][31][32], Zumaia [9,24,30,33] and Agost [24,34] (Spain), Gubbio [9,35,36] (Italy), El Kef [24,[37][38][39][40], Aïn Settara [24,30,39,41,42] and Elles [24,30,43] (Tunisia), La Lajilla [24,44] and Bochil [30,45] (Mexico), and Moncada [46] (Cuba) (Figure 1), which we studied preferably with high-resolution methodology. This selection includes the El Kef section, where the Global Boundary Stratotype Section and Point (GSSP) for the base of the Danian Stage was defined [37], and most of the designated auxiliary sections (Caravaca, Zumaia, Aïn Settara, Elles, and Bochil) [30].…”

“…Following the Geological Time Scale 2020 [54] for the early Danian, which is based on astronomical calibrations [55], we assign an age of 66.001 Ma to the KPB, 65.700 Ma to the C29r/C29n reversal, 64.862 Ma to C29n/C28r, 64.645 Ma to C28r/C28n, and 63.537 Ma to C28n/C27r: i.e., 0, 301, 1139, 1356 and 2464 kyr after the KPB, respectively (Table 1). [8], Agost (upper-middle bathyal; Spain) [34], Zumaia (middle bathyal; Spain) [9], Gubbio (lower bathyal; Italy) [9], El Kef (outer sublittoral-upper bathyal; Tunisia) [40], Aïn Settara (outer sublittoral; Tunisia) [41], Elles (outer sublittoral; Tunisia) [43], Moncada (upper bathyal; Cuba) [46], La Lajilla (lower bathyal; Mexico) [44], and Bochil (upper bathyal; Mexico) [45]. Red line = triserial guembelitriid group (Guembelitria and Chiloguembelitria).…”

“…For Acme-zone DanAZ3, dark green shading: dominance of Woodringina-Chiloguembelina, and light green shading: codominance of Woodringina-Chiloguembelina and other genera (Eoglobigerina-Subbotina-Parasubbotina-Globanomalina-Praemurica). [8], Agost (upper-middle bathyal; Spain) [34], Zumaia (middle bathyal; Spain) [9], Gubbio (lower bathyal; Italy) [9], El Kef (outer sublittoral-upper bathyal; Tunisia) [40], Aïn Settara (outer sublittoral; Tunisia) [41], Elles (outer sublittoral; Tunisia) [43], Moncada (upper bathyal; Cuba) [46], La Lajilla (lower bathyal; Mexico) [44], and Bochil (upper bathyal; Mexico) [45]. Red line = triserial guembelitriid group (Guembelitria and Chiloguembelitria).…”

“…Stratigraphic position (cm from the KPB) of tie-points, and their calibrated ages (in Ma and kyr after the KPB) according to GTS 2020 [54]. For the astrochronological or astronomical calibrations, we rely on new high-resolution biostratigraphic and cyclostratigraphic studies by Gilabert et al [9] on the Zumaia section (see details in Supplementary Table S2). The lowermost Danian at Zumaia is characterized by a ~9 cm thick dark clay bed, with a ~2 cm thick darker clay in its basal part, and a 1 to 2 mm thick airfall layer at its base containing the KPB impact material [9,[58][59][60].…”

“…The highest resolution of the planktic foraminiferal biostratigraphic scales is achieved in the lower Danian, after the Cretaceous/Paleogene boundary (KPB) mass extinction, because numerous small-size species began to appear following a model of "explosive" evolutionary radiation [3,4]. Planktic foraminiferal specialists have tended to establish increasingly detailed biozonations for the lower Danian in order to analyze in ever greater detail the succession, time, and duration of the rapid paleobiological, paleoenvironmental and paleoclimatic changes that occurred after the KPB, which are currently the subject of intensive study [5][6][7][8][9].…”