Publication Date:
2023-07-11
Description:
The Cretaceous Heterohelix moremani (Cushman) was the only biserial planktonic foraminiferal species from its first appearance in the late Albian up to the Cenomanian/Turonian boundary. Within that time, it increased gradually in abundance relative to other planktonic foraminifera in five Circum-North Atlantic sections. It is generally rare in upper Albian sediments, common in most of the Cenomanian and very abundant in sediments representing the latest Cenomanian Oceanic Anoxic Event. Short-term variations on the overall abundance trend correlate with positive excursions in the bulk carbonate delta13C record. Maximum rain rates of H. moremani during OAE2 show that this species was an opportunist that did well in extreme conditions, but its overall distribution indicates that it is not necessarily a marker for very high palaeoproductivity environments. Stable oxygen and carbon isotope measurements on foraminiferal species indicate that H. moremani was a surface water dweller at least in part of its geographic range, but incorporated 13C out of equilibrium with ambient seawater. It is depleted in delta13C relative to other planktonic foraminifera, which is attributed to vital effects related to its opportunistic character.
Keywords:
14-137; 80-551; Counting, foraminifera, planktic; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Foraminifera, benthic δ13C; Foraminifera, benthic δ18O; Glomar Challenger; Guembelitria cenomana, δ13C; Guembelitria cenomana, δ18O; Hedbergella delrioensis, δ13C; Hedbergella delrioensis, δ18O; Heterohelix moremani; Heterohelix moremani, δ13C; Heterohelix moremani, δ18O; Isotope ratio mass spectrometry; Leg14; Leg80; North Atlantic/ESCARPMENT; North Atlantic/HILL; ORDINAL NUMBER; Praeglobotruncana spp., δ13C; Praeglobotruncana spp., δ18O; Rotalipora cushmani, δ13C; Rotalipora cushmani, δ18O; Rotalipora gandolfii, δ13C; Rotalipora gandolfii, δ18O; Sample code/label; δ13C, carbonate; δ18O, carbonate
Type:
Dataset
Format:
text/tab-separated-values, 58 data points
