The planktic foraminiferal response to the Latest Danian Event (62.2 Ma)

The Paleocene and early Eocene (~66–40 Ma) is characterised by a number of transient warming events, also named hyperthermals. A more recent candidate for a hyperthermal of Paleocene age is the Latest Danian Event (LDE, ~62.2 Ma). So far, the LDE was only poorly explored in few deep-sea records and Tethyan shelf settings. Planktic data characterizing the surface ocean were almost completely missing. In this thesis, it was studied whether the LDE satisfies the requirements for a hyperthermal and the impact on the planktic foraminfera fauna. Samples from three late Danian deep-sea cores (ODP Sites 1210 and 1262, IODP Site U1407) and one Tethyan shelf section (Qreiya 3, Egypt) were investigated in rather high resolution, which, for the first time, allowed to unravel the impact of the LDE, the evolution of the ocean structure and planktic foraminiferal species abundances on an almost global scale. δ18O paleothermometry revealed a temperature rise of 2–4°C affecting the entire water column in all three depth habitats (sea floor, subsurface and surface ocean) and a contemporary negative carbon isotope excusion of 0.6–0.9 ‰ indicates carbon cycle perturbations. Changes in the planktic foraminiferal assemblages indicate a global biotic response to the LDE

The planktic foraminiferal response to the Latest Danian Event (62.2 Ma)

The Paleocene and early Eocene (~66–40 Ma) is characterised by a number of transient warming events, also named hyperthermals. A more recent candidate for a hyperthermal of Paleocene age is the Latest Danian Event (LDE, ~62.2 Ma). So far, the LDE was only poorly explored in few deep-sea records and Tethyan shelf settings. Planktic data characterizing the surface ocean were almost completely missing. In this thesis, it was studied whether the LDE satisfies the requirements for a hyperthermal and the impact on the planktic foraminfera fauna. Samples from three late Danian deep-sea cores (ODP Sites 1210 and 1262, IODP Site U1407) and one Tethyan shelf section (Qreiya 3, Egypt) were investigated in rather high resolution, which, for the first time, allowed to unravel the impact of the LDE, the evolution of the ocean structure and planktic foraminiferal species abundances on an almost global scale. δ18O paleothermometry revealed a temperature rise of 2–4°C affecting the entire water column in all three depth habitats (sea floor, subsurface and surface ocean) and a contemporary negative carbon isotope excusion of 0.6–0.9 ‰ indicates carbon cycle perturbations. Changes in the planktic foraminiferal assemblages indicate a global biotic response to the LDE

The planktic foraminiferal response to the Latest Danian Event (62.2 Ma)

The Paleocene and early Eocene (~66–40 Ma) is characterised by a number of transient warming events, also named hyperthermals. A more recent candidate for a hyperthermal of Paleocene age is the Latest Danian Event (LDE, ~62.2 Ma). So far, the LDE was only poorly explored in few deep-sea records and Tethyan shelf settings. Planktic data characterizing the surface ocean were almost completely missing. In this thesis, it was studied whether the LDE satisfies the requirements for a hyperthermal and the impact on the planktic foraminfera fauna. Samples from three late Danian deep-sea cores (ODP Sites 1210 and 1262, IODP Site U1407) and one Tethyan shelf section (Qreiya 3, Egypt) were investigated in rather high resolution, which, for the first time, allowed to unravel the impact of the LDE, the evolution of the ocean structure and planktic foraminiferal species abundances on an almost global scale. δ18O paleothermometry revealed a temperature rise of 2–4°C affecting the entire water column in all three depth habitats (sea floor, subsurface and surface ocean) and a contemporary negative carbon isotope excusion of 0.6–0.9 ‰ indicates carbon cycle perturbations. Changes in the planktic foraminiferal assemblages indicate a global biotic response to the LDE

The lithostratigraphy and biostratigraphy of the Chalk Group (Upper Coniacian to Upper Campanian) at Scratchell's Bay and Alum Bay, Isle of Wight, UK

The Scratchell's Bay and southern Alum Bay sections, in the extreme west of the Isle of Wight on the Needles promontory, cover the stratigraphically highest Chalk Group formations available in southern England. They are relatively inaccessible, other than by boat, and despite being a virtually unbroken succession they have not received the attention afforded to the Whitecliff GCR (Geological Conservation Review series) site at the eastern extremity of the island. A detailed account of the lithostratigraphy of the strata in Scratchell's Bay is presented and integrated with macro and micro biostratigraphical results for each formation present. Comparisons are made with earlier work to provide a comprehensive description of the Seaford Chalk, Newhaven Chalk, Culver Chalk and Portsdown Chalk formations for the Needles promontory. The strata described are correlated with those seen in the Culver Down Cliffs–Whitecliff Bay at the eastern end of the island that form the Whitecliff GCR site. This provides an overall correlation for the Upper Coniacian to Upper Campanian Chalk strata on the island. The influence of the Purbeck–Wight Structure (Sandown and Brighstone periclines) on the Chalk Group strata is discussed and the conclusions drawn demonstrate that movement on this structure is diachronous across the island

Paleoceanographic reconstruction of the Latest Danian Event at ODP Site 1210 (Shatsky Rise, Pacific Ocean)

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Planktic foraminiferal response to the Latest Danian Event in the Pacific Ocean (ODP Site 1210)

During the Paleocene the marine ecosystem was disturbed by several transient climate events, e.g. the Dan-C2 (65.2 Ma), the Latest Danian Event (LDE, 61.75 Ma), and most known, the Paleocene-Eocene Thermal Maximum (PETM, 56 Ma). So far the LDE (or “Top Chron 27n Event”) has rarely been studied in deep-sea sites with respect to the evolution and the paleoecology of planktic foraminifera. The event has already been described from Zumaia/Spain, Bjala/Bulgaria, Egypt, Shatsky Rise and Walvis Ridge. In the deep-sea the LDE is usually characterized by two distinctive Fe peaks in XRF core scanning data, paralleled by a prominent (∼0.7 negative δ13C excursion (CIE) in benthic foraminifera (Westerhold et al., 2008, 2011). Benthic foraminiferal δ18O data from nearby ODP Site 1209 suggest a bottom-water temperature rise of ∼2◦ C accompanying the negative CIE. Thus, the LDE has been considered as a further potential Paleocene “hyperthermal”. Here we present data from ODP Site 1210 of the biotic response (planktic foraminifera assemblages), carbonate preservation as well as δ18O and δ13C isotope signals of the surface, subsurface and benthic taxa covering a time span of about 900 kyr around the LDE. Among others, it is mainly investigated to what extent the LDE influences the ocean ecology and especially the surface waters. Trends of both δ18O and δ13C of planktic and benthic foraminifera show negative shifts at the onset of the LDE. A 0.6 drop within 100 ky in planktic δ18O data suggest a temperature rise of ∼2.5◦ C, whereas benthic foraminifera bottom water temperatures confirm a ∼2◦ C rise like measured at Site 1209. δ13C variation is more abrupt and pronounced than the δ18O shift at the base of the LDE. The decreasing δ13C gradient between surface and subsurface dwelling foraminifera suggests a weaker and or shallower thermocline. Thermocline dwelling asymbiotic Parasubbotina rise in abundance simultaneously to the decrease in the δ13C gradient which may suggest that this taxon benefits from a shallower thermocline and, thus, increased stratification. After the event, photosymbiotic activity in surface dwellers like Morozovella might have been boosted due to less competitive pressure. Minor dissolution according to planktic foraminiferal fragmentation, P/B-ratios and coarse fraction is considered to be present during the LDE. This observation is consistent with a decrease in the total CaCO3 record, which drops from ∼95% to 85%, while planktic foraminifera suffer a strong decrease in abundance from ∼20,000 to ∼1,000 speciemn per gram during the event. Results from Non-metric Multidimentional Scaling suggest distinct faunal changes between before, during and after the LDE. Prominent changes are especially the disappearance of Praemurica spp. shortly before or with the onset of the event, whereas Igorina albeari increases from ‘few’ to ‘abundant’ within the first Fe LDE peak. Morozovella angulata follows a slow but constant rise, while M. praeangulata has the opposite trend. Comparable obervations were done on genus level at the Tethys Ocean, Tunisia (Guasti et al., 2006).status: publishe

The planktic response to the Latest Danian Event (62.2 Ma) – A synthesis

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Stable isotope and benthic foraminiferal records of the Latest Danian Event at ODP Site 1262 (Walvis Ridge)

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Pronounced biotic and environmental change across the latest Danian warming event (LDE) at Shatsky Rise, Pacific Ocean (ODP Site 1210)

The early Paleogene is characterized by numerous hyperthermals, transient (< 200 kyr) ocean warming events, of which the Latest Danian Event (LDE, ~62.1 Ma) is one of the first. Although the LDE appears to be controlled by similar processes as early Eocene hyperthermals, the first open ocean benthic foraminiferal record across the LDE at Walvis Ridge revealed little faunal response. Here, we studied benthic foraminifera from the uppermost abyssal (2000–2500 m) ODP Site 1210, Shatsky Rise, Pacific Ocean, to provide a broader view of faunal response to the LDE. Late Danian oligotrophic background conditions are characterized by a Nuttallides umbonifera dominated assemblage. Yet, ~200 kyr before the LDE, benthic foraminiferal assemblages, with increased relative abundance of endobenthic morphotypes and benthic foraminiferal accumulation rates indicate a slightly enhanced food flux. A temperature increase ~40 kyr before the first carbon isotope excursion (CIE) of the LDE (= LDE1) is associated with a rise in abundance of Tappanina selmensis, suggesting episodic input of fresh phytodetritus. At the start of LDE1, and through the second CIE (= LDE2), the seafloor returned to more oligotrophic conditions. Between 220 and 430 kyr after the onset of the LDE, a second phase of episodic fresh phytodetritus input is suggested by a renewed dominance of T. selmensis. Although the patterns of faunal change during hyperthermals relate to local conditions (circulation patterns), the magnitude of faunal change is probably more related to an absolute temperature threshold.status: publishe

Size-related stable isotope changes in planktic foraminifera across the “Latest Danian Event” (ODP Site 1262, Walvis Ridge)

The Latest Danian Event (LDE, ∼62.15 Ma) represents a transient carbon cycle perturbation on a global scale similar to the Paleocene-Eocene Thermal Maximum, but of a much lower magnitude. This event took place during a time interval that is characterized by major changes in the calcareous plankton communities like the appearance and diversification of the fasciculithid nannolith group and the establishment of dinoflagellate photosymbiosis within the Praemurica/Morozovella planktic foraminifera. Size-related isotope changes (d13C, d18O) of planktic foraminifera might indicate changes in the depth habitat of foraminifera with ontogeny. An increase in d13C with size may point to the existence of (dinoflagellate) photosymbionts, and are often used to identify photosymbiosis in extinct foraminifera. Size fraction data on middle Paleocene taxa are generally rare and only poorly constrained concerning their stratigraphic age. Here we present detailed isotopic data from seven samples across the LDE of seven taxa including the asymbiotic Parasubbotina variospira and various symbiont-bearing taxa of the Praemurica, Morozovella and Igorina lineages that provide new insights into the life style of these taxa. Moreover, we intend to test if photosymbiotic activity changes occur during the LDE.status: publishe