14:30 〜 14:45
[BPT02-04] Benthic foraminiferal boron isotope signals through the Santonian
キーワード：Boron Isotopes, Late Cretaceous, benthic foraminifera
We investigated the δ11B isotope profiles in Cretaceous benthic foraminifera, focusing on the epibenthic species Notoplanulina rakauroana and Nuttallinella coronula. This study aims at understanding the implications of changes in δ11B isotope signatures for pH and alkalinity, associated with paleoenvironmental factors during the beginning of the Late Cretaceous cooling in the Santonian in the southern high latitudes.
We examine 10 levels through the Santonian of International Ocean Discovery Program (IODP) Site U1513 in the Mentelle Basin, some kilometres offshore Western Australia. Following a biostratigraphic framework relying on planktonic foraminifera and calcareous nannofossils, samples of Notoplanulina and Nuttallinella, representing significant elements of bottom water fauna through this period of cooling in surface and bottom waters.
The geochemical signals preserved in the tests of epibenthic foraminiferal species are supposedly less prone to representing vital effects as some stability in paleohabitat in bottom waters is plausable. The analysis of well-preserved specimens by Inductively Coupled Plasma Mass Spectrometry (ICPMS) required a cleaning protocol that involves several steps of ultrasonic baths in clear water and alcohol (see Henehan et al. 2019).
The results of benthic foraminiferal δ11B can add to the understanding of the relation between climate shifts and changes in the geochemical composition visible in foraminiferal tests and will provide additional insights into the reconstruction of prevailing pH levels and alkalinity in the bottom waters in the southern high latitudes.
We examine 10 levels through the Santonian of International Ocean Discovery Program (IODP) Site U1513 in the Mentelle Basin, some kilometres offshore Western Australia. Following a biostratigraphic framework relying on planktonic foraminifera and calcareous nannofossils, samples of Notoplanulina and Nuttallinella, representing significant elements of bottom water fauna through this period of cooling in surface and bottom waters.
The geochemical signals preserved in the tests of epibenthic foraminiferal species are supposedly less prone to representing vital effects as some stability in paleohabitat in bottom waters is plausable. The analysis of well-preserved specimens by Inductively Coupled Plasma Mass Spectrometry (ICPMS) required a cleaning protocol that involves several steps of ultrasonic baths in clear water and alcohol (see Henehan et al. 2019).
The results of benthic foraminiferal δ11B can add to the understanding of the relation between climate shifts and changes in the geochemical composition visible in foraminiferal tests and will provide additional insights into the reconstruction of prevailing pH levels and alkalinity in the bottom waters in the southern high latitudes.