Publikationsdatum:
2024-01-09
Beschreibung:
During the latest Cretaceous cooling phase, a positive shift in benthic foraminiferal d18O values lasting about 1.5 Myr (71.5-70 Ma) can be observed at a global scale (Campanian-Maastrichtian Boundary Event, CMBE). This d18O excursion is interpreted as being influenced by a change in intermediate- to deep-water circulation or by temporal build-up of Antarctic ice sheets. Here we test whether benthic foraminiferal assemblages from a southern high-latitudinal site near Antarctica (ODP Site 690) are influenced by the CMBE. If the d18O transition reflects a change in intermediate- to deep-water circulation from low-latitude to high-latitude water masses, then this change would result in cooler temperatures, higher oxygen concentration, and possibly lower organic-matter flux at the seafloor, resulting in a major benthic foraminiferal assemblage change. If, however, the d18O transition was mainly triggered by ice formation, no considerable compositional difference in benthic foraminiferal assemblages would be expected. Our data show a separation of the studied succession into two parts with distinctly different benthic foraminiferal assemblages. Species dominating the older part (73.0-70.5 Ma) tolerate less bottom water oxygenation and are typical components of low-latitude assemblages. In contrast, the younger part (70.0-68.0 Ma) is characterized by species that indicate well-oxygenated bottom waters and species common in high-latitude assemblages. We interpret the observed change in benthic foraminiferal assemblages toward a well-oxygenated environment to reflect the onset of a shift from low-latitude toward high-latitude dominated intermediate- to deep-water sources. This implies that a change in oceanic circulation was at least a major component of the CMBE.
Schlagwort(e):
113-690C; AGE; Alabamina sp.; Allomorphina cf. navarroana; Allomorphina minuta; Allomorphina sp.; Allomorphina trochoides; Angulogavelinella sp.; Aragonia velascoensis; Arenobulimina preslii; Arenobulimina sp.; Astacolus cretaceus; Astacolus sp.; Ataxophragmium rimosum; Biedafranciszkina polonica; Bolivina incrassata; Bolivina sp.; Bolivina witwickae; Bolivinoides paleocenicus; Bulimina sp.; Buliminella cf. excavata; Chrysalogonium tenuistriatum; Cibicides cf. excavata; Cibicidoides bembix; Cibicidoides sp.; Cibicidoides velascoensis; Cibicidoides voltzianus; Counting 〉125 µm fraction; Cuneus minutus; Cuneus trigona; Dentalina sp.; Dentalina sulcata; DEPTH, sediment/rock; Dorothia oxycona; Dorothia pupa; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Ellipsodimorphina hrubieszowcensis; Ellipsodimorphina sp.; Ellipsodimorphina variabilis; Ellipsoidella gracillima; Ellipsoidella kugleri; Ellipsoidella pleurostomelloides; Ellipsoidella polonica; Ellipsoidella sp.; Ellipsoidella variabilis; Epistominella alata; Eponides beisseli; Eponides concinna; Eponides sp.; Fissurina laticarinata; Fissurina orbignyana; Fissurina sp.; Foraminifera, benthic; Frondicularia frankei; Frondicularia lineata; Frondicularia sp.; Gaudryina pyramidata; Gaudryina sp.; Gavelinella beccariiformis; Gavelinella brotzeni; Gavelinella lorneiana; Gavelinella monterelensis; Gavelinella multipunctata; Gavelinella sp.; Globobulimina sp.; Globorotalites conicus; Globorotalites sp.; Globorotalites subconicus; Globulina lacrima; Globulina prisca; Globulina pseudopupa; Globulina subsphaerica; Guttulina cretacea; Guttulina pseudoscripta; Guttulina sp.; Guttulina trigonula; Gyroidina parva; Gyroidina sp.; Gyroidinoides lenticulus; Gyroidinoides nitidus; Gyroidinoides quadratus; Gyroidinoides tellburnaensis; Gyroidinoides umbilicatus; Joides Resolution; Laevidentalina catenula; Laevidentalina cf. siliqua; Laevidentalina communis; Laevidentalina concinna; Laevidentalina distincta; Laevidentalina monile; Laevidentalina oligostegia; Laevidentalina pseudonana; Laevidentalina soluta; Laevidentalina sp.; Lagena cf. grahami; Lagena paucicosta; Lagena semiinterrupta; Lagena semilineata; Lagena sp.; Lagena sulcatiformis; Lagena tricostulata; Leg113; Lenticulina cf. adenalensis; Lenticulina mariae; Lenticulina rotulata; Lingulina sp.; Marginulina loisana; Marginulina sp.; Milliammina spp.; Neoflabellina permutata; Neoflabellina reticulata; Neoflabellina rugosa; Neoflabellina sp.; Nodogenerina pseudoscripta; Nodosaria aspera; Nodosaria velascoensis; Nonion sp.; Nuttallides sp.; Nuttallides truempyi; Nuttallinella florealis; Ocean Drilling Program; ODP; Oolina globosa; Oolina sp.; Oolina sphaerica; Orbignyna ovata; Oridorsalis spp.; Osangularia cordieriana; Osangularia navarroana; Paralabamina hillebrandti; Paralabamina lunata; Paralabamina sp.; Paratrochamminoides sp.; Patellina trochiformis; Pleurostomella nitida; Pleurostomella subnodosa; Praebulimina pusilla; Praebulimina sp.; Praebulimina ventricosa; Procerolagena cylindrica; Pseudonodosaria manifesta; Pseudonodosaria sp.; Pullenia jarvisi; Pullenia marssoni; Pullenia reussi; Pyramidulina majuscula; Pyrolinoides acuminatus; Quadrimorphina allomorphinoides; Quadrimorphina camerata; Ramulina aculeata; Ramulina sp.; Reussella szajnochae; Reussoolina apiculata; Reussoolina simplex; Rosalina spp.; Rotaliidae; Sample code/label; Saracenaria cf. erlita; Saracenaria cf. navicula; Saracenaria sp.; Saracenaria triangularis; Sitella sp.; South Atlantic Ocean; Spiroplectammina sp.; Svenia laevigata; Trochammina sp.; Vaginulina trilobata
Materialart:
Dataset
Format:
text/tab-separated-values, 20881 data points
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