Data

 

96 datasets found! (Query time: 298 ms)

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1. März, C; Vogt, C; Schnetger, B et al. (2011): Geochemistry and mineralogy of Eocene-Oligocene sediments of IODP Hole 302-M0002A

   Abstract:

   In 2004, Integrated Ocean Drilling Program Expedition 302 (Arctic Coring Expedition, ACEX) to the Lomonosov Ridge drilled the first Central Arctic Ocean sediment record reaching the uppermost Cretaceous (~430 m composite depth). While the Neogene part of the record is characterized by grayish-yellowish siliciclastic material, the Paleogene part is dominated by biosiliceous black shale-type sediments. The lithological transition between Paleogene and Neogene deposits was initially interpreted as a single sedimentological unconformity (hiatus) of ~26 Ma duration, separating Eocene from Miocene strata. More recently, however, continuous sedimentation on Lomonosov Ridge throughout the Cenozoic was proclaimed, questioning the existence of a hiatus. […]

   Size:

   2 datasets

   https://doi.org/10.1594/PANGAEA.786428 - Score: 10.151
2. Sluijs, A; Schouten, S; Donders, TH et al. (2010): Geochemical and palynological results of IODP Hole 302-M0004A from Lomonosov Ridge, Arctic Ocean

   Abstract:

   Several episodes of abrupt and transient warming, each lasting between 50,000 and 200,000 years, punctuated the long-term warming during the Late Palaeocene and Early Eocene (58 to 51 Myr ago) epochs**1,2. These hyperthermal events, such as the Eocene Thermal Maximum 2 (ETM2) that took place about 53.5 Myr ago**2, are associated with rapid increases in atmospheric CO2 content. However, the impacts of most events are documented only locally**3,4. Here we show, on the basis of estimates from the TEX86' proxy, that sea surface temperatures rose by 3-5 °C in the Arctic Ocean during the ETM2. Dinoflagellate fossils demonstrate a concomitant freshening and eutrophication of surface waters, which resulted in euxinia in the photic zone. The presence of palm pollen implies**5 that coldest month mean temperatures over the Arctic land masses were no less than 8 °C, in contradiction of model simulations that suggest hyperthermal winter temperatures were below freezing**6. […]

   Size:

   5 datasets

   https://doi.org/10.1594/PANGAEA.735745 - Score: 10.151
3. Spofforth, DJA; Pälike, H; Green, DRH (2008): Paleogene record of elemental concentrations in sediments from the Arctic Ocean obtained by XRF analyses

   Abstract:

   We present a high-resolution X-ray fluorescence (XRF) core scanner record for the expanded middle Eocene section from Integrated Ocean Drilling Program (IODP) Expedition 302 (ACEX) drilled on the Lomonosov Ridge, central Arctic Ocean. The division of the middle Eocene into two units (subunit 1/6 and unit 2) is seen in the cyclical behavior of the elements as well as the changing interelemental correlations and their relationship to physical property measurements of bulk sediment. Al, Ti, and K strongly correlate throughout the record, while the behavior of Fe, Mn, and Si is more complex. Utilizing sediment geochemistry calibration to ground truth the XRF data, we suggest the middle Eocene Arctic Ocean was predominately euxinic, although periodic oxygenation of bottom waters must have occurred during unit 2 (49.7–45.4 Ma). Initially, the sediments are rich in biogenic silica (unit 2), but there is a pronounced shift to terrigenous dominated sediment accumulation in subunit 1/6. […]

   Size:

   4 datasets

   https://doi.org/10.1594/PANGAEA.695311 - Score: 9.686
4. Backman, J; Jakobsson, M; Frank, M et al. (2008): Age control and stratigraphy of a sediment profile from the Lomonosov Ridge, Arctic Ocean

   Abstract:

   The upper 200 m of the sediments recovered during IODP Leg 302, the Arctic Coring Expedition (ACEX), to the Lomonosov Ridge in the central Arctic Ocean consist almost exclusively of detrital material. The scarcity of biostratigraphic markers severely complicates the establishment of a reliable chronostratigraphic framework for these sediments, which contain the first continuous record of the Neogene environmental and climatic evolution of the Arctic region. Here we present profiles of cosmogenic 10Be together with the seawater-derived fraction of stable 9Be obtained from the ACEX cores. The down-core decrease of 10Be/9Be provides an average sedimentation rate of 14.5 ± 1 m/Ma for the uppermost 151 m of the ACEX record and allows the establishment of a chronostratigraphy for the past 12.3 Ma. The age-corrected 10Be concentrations and 10Be/9Be ratios suggest the existence of an essentially continuous sea ice cover over the past 12.3 Ma.

   Size:

   3 datasets

   https://doi.org/10.1594/PANGAEA.706556 - Score: 9.686
5. Darby, DA (2009): Drift distances, times and primary grain sources of the Arctic Ocean, Exp302 (ACEX)

   Abstract:

   Knowledge of the long-term history of the perennial ice is an important issue that has eluded study because the Cenozoic core material needed has been unavailable until the recent Arctic Coring Expedition (ACEX). Detrital Fe oxide mineral grains analyzed by microprobe from the last 14 Ma (164 m) of the ACEX composite core on the Lomonosov Ridge were matched to circum-Arctic sources with the same mineral and 12-element composition. These precise source determinations and estimates of drift rates were used to determine that these sand grains could not be rafted to the ACEX core site in less than a year. Thus the perennial ice cover has existed since 14 Ma except for the unlikely rapid return to seasonal ice between the average sampling interval of about 0.17 Ma. Both North America and Russia contributed significant Fe grains to the ACEX core during the last 14 Ma.

   Size:

   2 datasets

   https://doi.org/10.1594/PANGAEA.711530 - Score: 9.585
6. Stein, R; Boucsein, B; Meyer, H (2006): Bulk sedimentology from Sites M0002 and M0004 of the ACEX (Exp302) expedition to the Arctic Ocean

   Abstract:

   Except for a few discontinuous fragments of the Late Cretaceous/Early Cenozoic climate history and depositional environment, the paleoenvironmental evolution of the pre-Neogene central Arctic Ocean was virtually unknown prior to the IODP Expedition 302 (Arctic Ocean Coring Expedition – ACEX) drilling campaign on Lomonosov Ridge in 2004. Here we present detailed organic carbon (OC) records from the entire ca. 200 m thick Paleogene OC-rich section of the ACEX drill sites. These records indicate euxinic „Black Sea-type“ conditions favorable for the preservation of labile aquatic (marine algae-type) OC occur throughout the upper part of the early Eocene and the middle Eocene, explained by salinity stratification due to freshwater discharge. The superimposed short-term („Milankovitch-type“) variability in amount and composition of OC is related to changes in primary production and terrigenous input. […]

   Size:

   3 datasets

   https://doi.org/10.1594/PANGAEA.476007 - Score: 9.585
7. 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: 9.549
8. Stein, R (2007): Detailed analysis of the organic carbon content in sediment cores M0002 and M0004

   Abstract:

   During IODP Expedition 302 (Arctic Coring Expedition-ACEX), the first scientific drilling campaign in the permantly ice-covered central Arctic Ocean, a 430 m thick sequence of upper Cretaceaous to Quaternary sediments has been drilled. The lower half of this sequence is composed of organic-carbon-rich (black shale-type) sediments with total organic carbon contents of about 1–14%. Significant amounts of the organic matter preserved in these sediments is of algae-type origin and accumulated under anoxic/euxinic conditions. Here, for the first time detailed data on the source-rock potential of these black shales are presented, indicating that most of the Eocene sediments have a (fair to) good source-rock potential, prone to generate a gas/oil mixture. The source-rock potential of the Campanian and upper Paleocene sediments, on the other hand, is rather low. The presence of oil or gas already generated in situ, however, can be ruled out due to the immaturity of the ACEX sediments.

   Size:

   4 datasets

   https://doi.org/10.1594/PANGAEA.552044 - Score: 9.549
9. Vogt, C (2008): X-ray diffraction analysis of sediment cores from the ACEX expedition to the Arctic Ocean

   Abstract:

   This data report extents the X-ray diffraction (XRD) work reported in the Scientific Results Volume from ~ 200 samples to 1555 investigated bulk powder samples. The unique central Arctic Ocean samples of the International Ocean Drilling Program (IODP) Leg 302 Arctic Coring Expedition (ACEX), the first mission specific platform Leg, were collected and prepared by different German groups and provided to the Central Laboratory for Crystallography and Applied Material Sciences, Geosciences, University of Bremen. This data set is special because all samples were measured on the same diffractometer, used the same measurement settings and the diffractograms were investigated by the same person. Therefore, maximum continuity from the onshore party investigation till now is given. Sediments of the Arctic Ocean are dominated by detrital non-biogenic material in the Neogene and are also influenced by diagenetic processes over the whole section. […]

   Size:

   10 datasets

   https://doi.org/10.1594/PANGAEA.705057 - Score: 9.549
10. O'Regan, M; Sakamoto, T; King, JW (2008): Core correlation data and revised composite depth scale of Exp302 (ACEX) cores

    Abstract:

    Expedition 302 of the Integrated Ocean Drilling Program (IODP), also known as the Arctic Coring Expedition (ACEX), successfully penetrated a sequence of Cenozoic sediments draping the crest of the Lomonosov Ridge in the central Arctic Ocean. The cumulative sedimentary record spans the last 57 m.y. and was recovered from three sites located within 15 km of each other. Merging the recovered cores onto a common depth scale that accurately reflects their stratigraphic placement below the seafloor is a fundamental step toward interpreting this unique sedimentary record. However, the lack of overlapping recovery in adjacent holes and intervals of high core disturbance complicated traditional methods of stratigraphic correlation. Here we present a revised composite depth scale for the ACEX sediments, generated in part by performing a regional stratigraphic correlation with sediments recovered from previous expeditions to the Lomonosov Ridge. […]

    Size:

    10 datasets

    https://doi.org/10.1594/PANGAEA.707074 - Score: 9.549

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