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| Sarkar, Sudipta; Basak, Chandranath; Frank, Martin; Berndt, Christian; Huuse, Mads; Badhani, Shray; Bialas, Joerg. |
| The formation of the Antarctic Circumpolar Current (ACC) is critical for the evolution of the global climate, but the timing of its onset is not well constrained. Here, we present new seismic evidence of widespread Late Eocene to Oligocene marine diagenetic chert in sedimentary drift deposits east of New Zealand indicating prolonged periods of blooms of siliceous microorganisms starting ~36 million years ago (Ma). These major blooms reflect the initiation of the arrival and upwelling of northern-sourced, nutrient-rich deep equatorial Pacific waters at the high latitudes of the South Pacific. We show that this change in circulation was linked to the initiation of a proto-ACC, which occurred ~6 Ma earlier than the currently estimated onset of the ACC at... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00506/61778/65775.pdf |
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| Hillman, Jess I. T.; Klaucke, Ingo; Bialas, Joerg; Feldman, Howard; Drexler, Tina; Awwiller, David; Atgin, Orhan; Cifci, Gunay; Badhani, Shray. |
| A large geophysical dataset, including bathymetry, and 2D and 3D P-cable seismic data, revealed evidence of numerous gas flares near the S2 Canyon in the Danube Fan, northwestern Black Sea. This dataset allows us to investigate potential relationships between gas migration pathways, gas vents observed at the seafloor and submarine slope failures. Vertical gas migration structures as revealed in the seismics appear to be concentrated near submarine slope failure structures. Where these seismically defined features extend upwards to the seafloor, they correlate with the location of gas flares. However, not all these structures reach the seafloor, in some cases because they are capped by overlying sediments. A strong correlation is inferred between gas... |
| Tipo: Text |
Palavras-chave: Gas migration; Chimneys; Gas hydrate; Danube Fan; Slope failure; Black Sea. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55013/57803.pdf |
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| Lange, Dietrich; Kopp, Heidrun; Royer, Jean-yves; Henry, Pierre; Cakir, Ziyadin; Petersen, Florian; Sakic, Pierre; Ballu, Valerie; Bialas, Joerg; Ozeren, Mehmet Sinan; Ergintav, Semih; Geli, Louis. |
| Using offshore geodetic observations, we show that a segment of the North Anatolian Fault in the central Sea of Marmara is locked and therefore accumulating strain. The strain accumulation along this fault segment was previously extrapolated from onshore observations or inferred from the absence of seismicity, but both methods could not distinguish between fully locked or fully creeping fault behavior. A network of acoustic transponders measured crustal deformation with mm-precision on the seafloor for 2.5 years and did not detect any significant fault displacement. Absence of deformation together with sparse seismicity monitored by ocean bottom seismometers indicates complete fault locking to at least 3 km depth and presumably into the crystalline... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00507/61838/65897.pdf |
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