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: 9.333
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: 8.787
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: 8.787
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: 8.787
15. St. John, KEK (2010): (Table 1) Summary of general lithology in IODP Exp302 cores

    Abstract:

    The Cenozoic ice-rafted debris (IRD) history of the central Arctic is reconstructed utilizing the terrigenous coarse sand fraction in IODP 302 cores from 0 to 273 meters composite depth. This Holocene - middle Eocene quantitative record of terrigenous sand accumulation on the Lomonosov Ridge, along with qualitative information on grain texture and composition, confirms the interpretation that ice initiation (sea ice and glacial ice) occurred ~46 Ma in the Arctic, and provides a long-term pattern of Arctic ice expansion and decay since the middle Eocene. IRD mass accumulation rates range from 0 to 0.13 g/cm2/ka in the middle Eocene and from 0 to 0.36 g/cm2/ka in the Neogene. IRD mass accumulation rate (MAR) maxima in the Miocene and Pliocene cooccur with either glacial initiation or intensification in the sub-Arctic. […]

    Size:

    41 data points

    https://doi.org/10.1594/PANGAEA.734547 - Score: 8.772
16. Onodera, J; Takahashi, K; Jordan, RW (2010): (Table 2) Similarity Indexes (Pearson's correlation coefficient) of the silicoflagellate assemblages of IODP Exp302

    Abstract:

    The silicoflagellate and ebridian assemblages in early middle Eocene Arctic cores obtained by IODP Expedition 302 (ACEX) were studied in order to decipher the paleoceanography of the upper water column. The assemblages in Lithologic Unit 2 (49.7-45.1 Ma), one of the biosiliceous intervals, were usually endemic as compared to the assemblages that occurred outside of the Arctic Ocean. The presence of these endemic assemblages is probably due to a unique environmental setting, controlled by the degree of mixing between the low-salinity Arctic waters and relatively high salinity waters supplied from outside the Arctic Ocean, such as the Atlantic and possibly the Western Siberian Sea. Using the basin-to-basin fractionation model, the early middle Eocene Arctic Ocean corresponds to an estuarine circulation type, which includes the modern-day Black Sea. […]

    Size:

    20 data points

    https://doi.org/10.1594/PANGAEA.733882 - Score: 8.772
17. Eynaud, F; Cronin, TM; Smith, SA et al. (2009): (Table 1) Late Pleistocene planktonic foraminifera of Hole 302-M0004C

    Abstract:

    Planktonic foraminifera populations were studied throughout the top 25 meters of the IODP ACEX 302 Hole 4C from the central Arctic Ocean at a resolution varying from 5cm (at the top of the record) to 10cm. Planktonic foraminifera occur in high absolute abundances only in the uppermost fifty centimetres and are dominated by the taxa Neogloboquadrina pachyderma. Except for a few intermittent layers below this level,most samples are barren of calcareous microfossils.Within the topmost sediments, Neogloboquadrina pachyderma specimens present large morphological variability in the shape and number of chambers in the finalwhorl, chamber sphericity, size, and coiling direction. Five morphotypeswere identified among the sinistral (sin.) population (Nps-1 to Nps-5), including a small form (Nps-5) that is similar to a non-encrusted normal form also previously identified in the modern Arctic Ocean watermasses. […]

    Size:

    943 data points

    https://doi.org/10.1594/PANGAEA.672078 - Score: 8.772
18. Pagani, M; Pedentchouk, N; Huber, M et al. (2006): Stable carbon isotope ratios of alkane of IODP Hole 302-M0004A

    Abstract:

    The Palaeocene/Eocene thermal maximum represents a period of rapid, extreme global warming approx ~55 million years ago, superimposed on an already warm world (Zachos et al., 2003, doi:10.1126/science.1090110; Bowen et al., 2004, doi:10.1038/nature03115; Thomas et al., 2002, doi:10.1130/0091-7613(2002)030<1067:WTFFTF>2.0.CO;2). This warming is associated with a severe shoaling of the ocean calcite compensation depth **4 and a >2.5 per mil negative carbon isotope excursion in marine and soil carbonates (Zachos et al., 2003, doi:10.1126/science.1090110; Bowen et al., 2004, doi:10.1038/nature03115; Thomas et al., 2002, doi:10.1130/0091-7613(2002)030<1067:WTFFTF>2.0.CO;2; Zachos et al., doi:10.1126/science.1109004). Together these observations indicate a massive release of 13C-depleted carbon (Zachos et al., doi:10.1126/science.1109004) and greenhouse-gas-induced warming. […]

    Size:

    417 data points

    https://doi.org/10.1594/PANGAEA.733130 - Score: 8.772
19. 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: 8.706
20. 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: 8.706

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