ON SPREADING OF ANTARCTIC BOTTOM WATER IN FRACTURE ZONES OF THE MID-ATLANTIC RIDGE AT 7–8°N On spreading of Antarctic Bottom Water in fracture zones of the Mid-Atlantic Ridge at 7–8°N

Published in Russian Journal of Earth Sciences · Volume 22, Issue 5 · Pages 1–17 · Rubric: ORIGINAL ARTICLES
DOI: https://doi.org/10.2205/2022ES000783
Received: 09.10.2021 Accepted: 26.05.2022 Published: 04.12.2022 Language of publication: ENG
Authors
A Data-Interpolating Variational Analysis in n-dimensions was used to describe a potential temperature distribution in the bottom layer of the fracture zones of the Mid-Atlantic Ridge at 7–8°N. This analysis was based on a new digital terrain model obtained by supplementing the STRM15+ bathymetry data with multibeam echo sounding data from the 33rd cruise of the research vessel Akademik Nikolaj Strakhov (2016) and oceanological data from the World Ocean Database, supplemented with CTD profiles and reversing thermometer data measured in scientific cruises of the Shirshov Institute of Oceanology, Russian Academy of Sciences in 2014–2016. A 2D model of near-bottom potential temperature distribution in the study area was calculated based on the analysis. The model allows us to propose the Antarctic Bottom Water propagation pattern through the Doldrums, Vernadsky, and Pushcharovsky fracture zones. It is shown that bottom water warms up when passing fracture zones from 1.4°C in Pushcharovsky Fracture Zone up to 1.6–1.7°C in Vernadsky Fracture Zone. Bottom water from Pushcharovsky and Vernadsky fractures propagates in two directions. Northernly, it propagates to the Doldrums Fracture Zone, where its temperature reaches about 1.9–2.0°C. Easterly, it flows along Pushcharovsky Fracture Zone and raising the temperature up to 1.8–2.0°C. We propose the absence of Antarctic Bottom Water's overflow with a temperature less than 1.8°C to the East Atlantic in the study area.
Antarctic Bottom Water, Mid-Atlantic Ridge, fracture zones, bottom topography, multibeam echo sounding, potential temperature
Funding
The expedition and the primary processing of the data obtained during the 33rd cruise of the R/V Akademik Nikolaj Strakhov (2016) were supported by the state assignment of IO RAS, no. FMWE-2021-0012. The analysis and interpretation of the data were funded by the project of the Russian Science Foundation no. 19- 17-00246. The data obtained during cruises 39th– 41st of the R/V Akademik Sergey Vavilov were analyzed within the framework of the project of the Russian Foundation for Basic Research no. 20-08- 00246. The authors are grateful to Prof. E. G. Morozov (IO RAS) for providing oceanographic data obtained during the 39th–41st cruises of the R/V Akademik Sergey Vavilov and to Prof. S. A. Dobrolyubov (Lomonosov Moscow State University) for providing thermometers for the 33rd cruise of the R/V Akademik Nikolaj Strakhov. The authors also express their gratitude to the participants of the 33rd cruise of the R/V Akademik Nikolaj Strakhov: I. A. Mironov (Lomonosov Moscow State University), V. M. Pyatakov, and A. B. Demenina (IO RAS) for their help in collecting of oceanographic and bathymetric data and the crew of the R/V for their assistance in carrying out the scientific work. The authors are grateful to Dr. D. V. Dorokhov (IO RAS) for fruitful discussion and valuable recommendations and to T. Glazkova (Royal Holloway, University of London) for English corrections.
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