Universität zu Köln

Gruetzner, Jens ORCID: 0000-0001-5445-2393, Jimenez Espejo, Francisco J., Lathika, Nambiyathodi, Uenzelmann-Neben, Gabriele ORCID: 0000-0002-0115-5923, Hall, Ian R., Hemming, Sidney R., LeVay, Leah J., Barker, S., Berke, M. A., Brentegani, L., Caley, T., Cartagena-Sierra, A., Charles, C. D., Coenen, J. J., Crespin, J. G., Franzese, A. M., Han, X., Hines, S. K. V., Just, J., Koutsodendris, A., Kubota, K., Norris, R. D., Santos, T. P., Robinson, R., Rolinson, J. M., Simon, M. H., Tangunan, D., van der Lubbe, H. J. L., Yamane, M. and Zhang, H. (2019). A New Seismic Stratigraphy in the Indian-Atlantic Ocean Gateway Resembles Major Paleo-Oceanographic Changes of the Last 7 Ma. Geochem. Geophys. Geosyst., 20 (1). S. 339 - 359. WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 1525-2027

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Abstract

The exchange of water masses between the Indian Ocean and the Atlantic constitutes an integral interocean link in the global thermohaline circulation. Long-term changes in deep water flow have been studied using seismic reflection profiles but the seismic stratigraphy was poorly constrained and not resolved for the time period from the late Miocene onward. Here we present results from International Ocean Discovery Program Site U1475 (Agulhas Plateau) located over a sediment drift proximal to the entrance of North Atlantic Deep Water into the Southern Ocean and South Indian Ocean. Site U1475 comprises a complete carbonate-rich stratigraphic section of the last similar to 7 Ma that provides an archive of climate-induced variations in ocean circulation. Six marker reflectors occurring in the upper 300 m of the drift are identified here for the first time. The formation of these reflectors is mainly due to density changes that are mostly caused by changes in biogenic versus terrigenous sediment deposition. Synthetic seismograms allow age assignments for the horizons based on biostratigraphy and magnetostratigraphy. Prominent reflectors are related to late Pleistocene glacial/interglacial variability, the middle and early Pleistocene transitions, and the onset of the northern hemisphere glaciation. A peculiar early Pliocene interval (similar to 5.3-4.0 Ma) bounded by two reflectors is characterized by fourfold elevated sedimentation rates (> 10 cm/kyr) and the occurrence of sediment waves. We argue that this enhanced sediment transport to the Agulhas Plateau was caused by a reorganization of the bottom current circulation pattern due to maximized inflow of North Atlantic Deep Water.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Gruetzner, Jens UNSPECIFIED orcid.org/0000-0001-5445-2393 UNSPECIFIED Jimenez Espejo, Francisco J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lathika, Nambiyathodi UNSPECIFIED UNSPECIFIED UNSPECIFIED Uenzelmann-Neben, Gabriele UNSPECIFIED orcid.org/0000-0002-0115-5923 UNSPECIFIED Hall, Ian R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hemming, Sidney R. UNSPECIFIED UNSPECIFIED UNSPECIFIED LeVay, Leah J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Barker, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Berke, M. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Brentegani, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Caley, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cartagena-Sierra, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Charles, C. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Coenen, J. J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Crespin, J. G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Franzese, A. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Han, X. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hines, S. K. V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Just, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Koutsodendris, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kubota, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Norris, R. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Santos, T. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Robinson, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rolinson, J. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Simon, M. H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Tangunan, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED van der Lubbe, H. J. L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Yamane, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zhang, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-139693
DOI:	10.1029/2018GC007668
Journal or Publication Title:	Geochem. Geophys. Geosyst.
Volume:	20
Number:	1
Page Range:	S. 339 - 359
Date:	2019
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	1525-2027
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language DEEP-WATER CIRCULATION; AGULHAS PLATEAU; MARINE SEDIMENT; LATE MIOCENE; OVERTURNING CIRCULATION; BULK-DENSITY; SEA-LEVEL; PLIOCENE; IMPACTS; CLIMATE Multiple languages Geochemistry & Geophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13969