Museum Salling

<strong class="journal-contentHeaderColor">Abstract.</strong> There is a temporal correlation between the peak activity of the North Atlantic Igneous Province (NAIP) and the Paleocene&ndash;Eocene Thermal Maximum (PETM), suggesting that the NAIP may have initiated and/or prolonged this extreme warming event. However, corroborating a causal relationship is hampered by a scarcity of expanded sedimentary records that contain both climatic and volcanic proxies. One locality hosting such a record is Fur Island in Denmark, where an expanded pre- to post-PETM succession containing hundreds of NAIP ash layers is exceptionally well preserved. We compiled a range of environmental proxies, including mercury (Hg) anomalies, paleotemperature proxies, and lithium (Li) and osmium (Os) isotopes, to trace NAIP activity, hydrological changes, weathering, and seawater connectivity across this interval. Volcanic proxies suggest that NAIP activity was elevated before the PETM and appears to have peaked during the body of the &delta;¹³C excursion, but decreased considerably during the PETM recovery. This suggests that the acme in NAIP activity, dominated by flood basalt volcanism and thermogenic degassing from contact metamorphism, was likely confined to just ~200 kyr (ca. 56.0&ndash;55.8 Ma). The hundreds of thick basaltic ashes in the post-PETM strata likely represent a change from effusive to explosive activity, rather than an increase in NAIP activity. Detrital &delta;⁷Li values and clay abundances suggest that volcanic ash production increased basaltic reactive surface area, likely enhancing silicate weathering and atmospheric carbon sequestration in the early Eocene. Signals in lipid biomarkers and Os isotopes, traditionally used to trace paleotemperature and weathering changes, are used here to track seaway connectivity. These proxies indicate that the North Sea was rapidly cut off from the North Atlantic in under 12 kyr during the PETM recovery due to NAIP thermal uplift. Our findings reinforce the hypothesis that the emplacement of the NAIP had a profound and complex impact on Paleocene&ndash;Eocene climate, both directly through volcanic and thermogenic degassing, and indirectly by driving regional uplift and changing seaway connectivity.

Abstract. There is a temporal correlation between the peak activity of the North Atlantic Igneous Province (NAIP) and the Paleocene–Eocene Thermal Maximum (PETM), suggesting that the NAIP may have initiated and/or prolonged this extreme warming event. However, corroborating a causal relationship is hampered by a scarcity of expanded sedimentary records that contain both climatic and volcanic proxies. One locality hosting such a record is Fur Island in Denmark, where an expanded pre- to post-PETM succession containing hundreds of NAIP ash layers is exceptionally well preserved. We compiled a range of environmental proxies, including mercury (Hg) anomalies, paleotemperature proxies, and lithium (Li) and osmium (Os) isotopes, to trace NAIP activity, hydrological changes, weathering, and seawater connectivity across this interval. Volcanic proxies suggest that NAIP activity was elevated before the PETM and appears to have peaked during the body of the δ13C excursion, but decreased considerably during the PETM recovery. This suggests that the acme in NAIP activity, dominated by flood basalt volcanism and thermogenic degassing from contact metamorphism, was likely confined to just ~200 kyr (ca. 56.0–55.8 Ma). The hundreds of thick basaltic ashes in the post-PETM strata likely represent a change from effusive to explosive activity, rather than an increase in NAIP activity. Detrital δ7Li values and clay abundances suggest that volcanic ash production increased basaltic reactive surface area, likely enhancing silicate weathering and atmospheric carbon sequestration in the early Eocene. Signals in lipid biomarkers and Os isotopes, traditionally used to trace paleotemperature and weathering changes, are used here to track seaway connectivity. These proxies indicate that the North Sea was rapidly cut off from the North Atlantic in under 12 kyr during the PETM recovery due to NAIP thermal uplift. Our findings reinforce the hypothesis that the emplacement of the NAIP had a profound and complex impact on Paleocene–Eocene climate, both directly through volcanic and thermogenic degassing, and indirectly by driving regional uplift and changing seaway connectivity.

We propose Danowhetaksa n. gen. (Odonata: Whetwhetaksidae) with two new species: D. birgitteae n. gen. et sp. and D. rusti n. gen. et sp. from the earliest Ypresian Stolleklint clay of the lst Formation in northwestern Denmark. Whetwhetaksidae has previously been known only from the Ypresian Okanagan Highlands of far-western North America, the new records are, therefore, the first from the Palearctic Region.

Fossilized eyes permit inferences of the visual capacity of extinct arthropods1-3. However, structural and/or chemical modifications as a result of taphonomic and diagenetic processes can alter the original features, thereby necessitating comparisons with modern species. Here we report the detailed molecular composition and microanatomy of the eyes of 54-million-year-old crane-flies, which together provide a proxy for the interpretation of optical systems in some other ancient arthropods. These well-preserved visual organs comprise calcified corneal lenses that are separated by intervening spaces containing eumelanin pigment. We also show that eumelanin is present in the facet walls of living crane-flies, in which it forms the outermost ommatidial pigment shield in compound eyes incorporating a chitinous cornea. To our knowledge, this is the first record of melanic screening pigments in arthropods, and reveals a fossilization mode in insect eyes that involves a decay-resistant biochrome coupled with early diagenetic mineralization of the ommatidial lenses. The demonstrable secondary calcification of lens cuticle that was initially chitinous has implications for the proposed calcitic corneas of trilobites, which we posit are artefacts of preservation rather than a product of in vivo biomineralization4-7. Although trilobite eyes might have been partly mineralized for mechanical strength, a (morelikely) organic composition would have enhanced function via gradient-index optics and increased control of lens shape.

Lowermost Eocene expanded marine sedimentary successions in Denmark are of global chronostratigraphic significance, due to the excellently preserved terrestrial and marine fossil assemblages, combined with a number of radiometrically dated ash layers. A detailed study of vegetation changes across the Palaeocene–Eocene Thermal Maximum (PETM) interval have not yet been carried out, nor has the microflora (e.g., spores and pollen) been related to existing macrofloral remains (e.g., seeds and leaves) stored in Danish Museums. This palynological research project on vegetation changes across the PETM interval is significant because there are extremely few PETM vegetation records where a complete, highresolution plant response to this transient event can be examined. Herein, we present preliminary microflora results from an expanded marine PETM record obtained from the Østerrenden drill core (DGI 83101), located in Store Bælt, Denmark. This preliminary study reveals that a distinct microflora change correlates with the Carbon Isotope Excursion (CIE) in the Østerrenden drill core, including a change from low to high diversity across the Palaeocene–Eocene boundary. The Palaeocene assemblages comprise a high relative abundance of Inaperturopollenites spp. (taxodiaceae), but above the stratigraphic level corresponding to the onset of the CIE event this Palaeocene assemblage type is replaced by species such as Caryapollenitescirculus, Platycaryapollenites platycaryoides, and Tricolpopollenites librarensis. These typical early Eocene pollen species originated from ancestors of Juglandaceae (walnut) and Fagus (beech) families. Palaeotropical floral elements such as palm pollen (Arecipites spp.) and angiosperm pollen from Anacolosa spp. (Olacaceae) also occur for the first time in the basal Eocene part of the Østerrenden drill core. An increased abundance of pollen typical of wet lowland areas, such as Sparganiaceaepollenites spp. (Typhaceae), is also observed, indicating a change in the hydrological regime towards increased seasonality during the earliest Eocene.

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