Data

 

96 datasets found! (Query time: 1 ms)

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11. Krylov, AA; Andreeva, IA; Vogt, C et al. (2008): Mineralogical composition of the upper 300m of Hole 302-M0002A

    Abstract:

    During the Arctic Coring Expedition (ACEX), a 428-m-thick sequence of Upper Cretaceous to Quaternary sediments was penetrated. The mineralogical composition of the upper 300 m of this sequence is presented here for the first time. Heavy and clay mineral associations indicate a major and consistent shift in provenance, from the Barents-Kara - western Laptev Sea region, characterized by presence of common clinopyroxene, to the eastern Laptev-East Siberian seas in the upper part of the section, characterized by common hornblende (amphibole). Sea ice originating from the latter source region must have survived at least one summer melt cycle in order to reach the ACEX drill site, if considering modern sea ice trajectories and velocities. This shift in mineral assemblages probably represents the onset of a perennial sea ice cover in the Arctic Ocean, which occurred at about 13 Ma, thus suggesting a coeval freeze in the Arctic and Antarctic regions.

    Size:

    3 datasets

    https://doi.org/10.1594/PANGAEA.707428 - Score: 9.341
12. Sangiorgi, F; Brumsack, H-J; Willard, DA et al. (2010): (Table 1) Element enrichment in dark versus light layers of the ''Zebra'' interval of IODP Hole 302-M0002A

    Size:

    57 data points

    https://doi.org/10.1594/PANGAEA.733255 - Score: 8.803
13. Weller, P; Stein, R (2010): (Table 1) CPI17-23, hopanoic acid, and n-C35 + lycopane/n-C31 ratios as well as 17beta(H), 21beta(H) homohopane, long-chain alkanes, and alkenones concentrations in IODP Exp302

    Abstract:

    During Integrated Ocean Drilling Program Expedition 302 (Arctic Coring Expedition (ACEX)) a more than 200 m thick sequence of Paleogene organic carbon (OC)-rich (black shale type) sediments was drilled. Here we present new biomarker data determined in ACEX sediment samples to decipher processes controlling OC accumulation and their paleoenvironmental significance during periods of Paleogene global warmth and proposed increased freshwater discharge in the early Cenozoic. Specific source-related biomarkers including n-alkanes, fatty acids, isoprenoids, carotenoids, hopanes/hopenes, hopanoic acids, aromatic terpenoids, and long-chain alkenones show a high variability of components, derived from marine and terrestrial origin. The distribution of hopanoic acid isomers is dominated by compounds with the biological 17beta(H), 21beta(H) configuration indicating a low level of maturity. […]

    Size:

    394 data points

    https://doi.org/10.1594/PANGAEA.733333 - Score: 8.803
14. Eynaud, F (2007): Late Pleistocene planktonic foraminifera of Hole 302-M0004C (Addendum 1)

    Size:

    4208 data points

    https://doi.org/10.1594/PANGAEA.672076 - Score: 8.803
15. Sluijs, A; Schouten, S; Pagani, M et al. (2006): (Table S1) Palynology of IODP Hole 302-M0004A

    Abstract:

    The Palaeocene/Eocene thermal maximum, 55 million years ago, was a brief period of widespread, extreme climatic warming (Zachos et al., 2003; Kennett and Stott, 1991, doi:10.1038/353225a0; Tripati and Elderfield, 2005, doi:10.1126/science.1109202), that was associated with massive atmospheric greenhouse gas input (Dickens et al., 1995, doi:10.1029/95PA02087). Although aspects of the resulting environmental changes are well documented at low latitudes, no data were available to quantify simultaneous changes in the Arctic region. Here we identify the Palaeocene/Eocene thermal maximum in a marine sedimentary sequence obtained during the Arctic Coring Expedition (Backman et al., 2006, doi:10.2204/iodp.proc.302.2006). We show that sea surface temperatures near the North Pole increased from 18 °C to over 23 °C during this event. Such warm values imply the absence of ice and thus exclude the influence of ice-albedo feedbacks on this Arctic warming. […]

    Size:

    1185 data points

    https://doi.org/10.1594/PANGAEA.769815 - Score: 8.644
16. Eynaud, F (2011): Planktonic foraminifera and microfossil composition of IODP Hole 302-M0004C

    Abstract:

    Calcareous microfossils are widely used by paleoceanographers to investigate past sea-surface hydrology. Among these microfossils, planktonic foraminifera are probably the most extensively used tool (e.g. [1] for a review), as they are easy to extract from the sediment and can also be used for coupled geochemical (e.g; d18O, d13C, Mg/Ca) and paleo-ecological investigations. Planktonic foraminifera are marine protists, which build a calcareous shell made of several chambers which reflect in their chemistry the properties of the ambient water-masses. Planktonic foraminifera are known to thrive in various habitats, distributed not only along a latitudinal gradient, but also along different water-depth intervals within surface waters (0-1000 m). Regarding their biogeographical distribution, planktonic foraminifera assemblages therefore mirror different water-masses properties, such as temperature, salinity and nutrient content of the surface water in which they live. […]

    Size:

    3709 data points

    https://doi.org/10.1594/PANGAEA.788078 - Score: 8.644
17. Ogawa, Y; Takahashi, K; Yamanaka, T (2012): (Table 2) Geochemical analysis from IODP Exp302

    Abstract:

    Geochemical analyses of biogenic opal, total organic carbon (TOC), total sulfur (TS), and stable sulfur isotopic composition were conducted on the middle Eocene section of the ACEX cores obtained by IODP Expedition 302. The analyzed %TS contents were high in all the examined intervals, indicating sufficient sea water was present in the deep layer of the paleo Arctic basin in contrast with the low salinity surface waters determined by freshwater siliceous microfossils. From the high %TS in Lithological Unit 1/6, the extent of sea water supply from outside of the Arctic basin appeared to have increased after 45 Ma. The euxinic condition of the bottom water is suggested by the TOC-TS diagram. The anoxic environment was brought about by the estuarine type circulation pattern and salinity stratification. The light sulfur isotope composition (d34S) indicates the microbial sulfate reduction in an open system. […]

    Size:

    1738 data points

    https://doi.org/10.1594/PANGAEA.787402 - Score: 8.644
18. Weijers, JWH; Schouten, S; Sluijs, A et al. (2007): Reconstruction of continental mean air temperature across the PETM of IODP Hole 302-M0004A (Appendix A)

    Abstract:

    The Palaeocene-Eocene Thermal Maximum (PETM; ~55.5 Ma) is a geologically relatively brief episode of extreme warmth. Both deep and surface ocean temperatures increased by up to 5 °C in equatorial waters and up to 8 °C in mid and high latitude waters. From the continents, the annual mean air temperature response during the PETM is still largely unknown, mainly due to a lack of quantitative temperature proxies and sufficient suitable, continuous high resolution records. Recently, a new proxy for continental temperature reconstructions has been proposed, based on the distribution of membrane lipids of bacteria in present-day soils [Weijers et al., 2007, doi:10.1016/j.gca.2006.10.003] and shown to reconstruct annual mean air temperature. […]

    Size:

    219 data points

    https://doi.org/10.1594/PANGAEA.707279 - Score: 8.644
19. Ogawa, Y; Takahashi, K; Yamanaka, T et al. (2009): (Appendix A) Geochemistry for Units 1/6, 2, and the upper part of Unit 3 of IODP Holes 302-M0002A and 302-M0004A

    Abstract:

    Integrated Ocean Drilling Program (IODP) Expedition 302 Arctic Coring Expedition (ACEX) obtained the first relatively continuous long sediment cores from the Lomonosov Ridge in the central Arctic Ocean in 2004. Preceding microfossil studies indicated the dominance of low salinity surface waters in the early to middle Eocene Arctic basin. The main purpose of this study is to reconstruct paleoceanographic conditions including the extent of saline (seawater) mass presence. To attain this goal we performed geochemical analyses of total sulfur (%TS), total organic carbon (%TOC) and stable sulfur isotopic composition (d34S) on the early to middle Eocene section of the ACEX cores. The %TS were high in all the examined intervals and the sedimentary sulfur occurred mainly as framboidal pyrite, indicating that sufficient sulfate, indicative of seawater, was present in the deep layer of the paleo-Arctic basin and that the pyrite was formed in the sediments under sufficient iron input. […]

    Size:

    909 data points

    https://doi.org/10.1594/PANGAEA.785796 - Score: 8.644
20. Sluijs, A; Röhl, U; Schouten, S et al. (2008): (Table 1) Elemental mean values of the upper Paleocene and lower Eocene in IODP Hole 302-M0004A

    Abstract:

    We reconstruct the latest Paleocene and early Eocene (~57-50 Ma) environmental trends in the Arctic Ocean and focus on the Paleocene-Eocene thermal maximum (PETM) (~55 Ma), using strata recovered from the Lomonosov Ridge by the Integrated Ocean Drilling Program Expedition 302. The Lomonosov Ridge was still partially subaerial during the latest Paleocene and earliest Eocene and gradually subsided during the early Eocene. Organic dinoflagellate cyst (dinocyst) assemblages point to brackish and productive surface waters throughout the latest Paleocene and early Eocene. Dinocyst assemblages are cosmopolitan during this time interval, suggesting warm conditions, which is corroborated by TEX86'-reconstructed temperatures of 15°-18°C. Inorganic geochemistry generally reflects reducing conditions within the sediment and euxinic conditions during the upper lower Eocene. […]

    Size:

    125 data points

    https://doi.org/10.1594/PANGAEA.733796 - Score: 8.597

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