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Abrupt transition from magma-starved to magma-rich rifting in the eastern Black Sea

Abrupt transition from magma-starved to magma-rich rifting in the eastern Black Sea
Abrupt transition from magma-starved to magma-rich rifting in the eastern Black Sea
The amount of magmatism that accompanies the extension and rupture of the continental lithosphere varies dramatically at rifts and margins around the world. Based on widely spaced geophysical transects, some margins are known to preserve a transition from magmatically robust to magmatically starved rifting along strike, but the nature of the transition is unknown. Wide-angle seismic data from the Black Sea provide the first direct observations of such a transition and show that it is abrupt, occurring over only ~20–30 km, and coincides with a transform fault. This abrupt transition cannot be explained solely by gradual along-margin variations in mantle properties, since these would be expected to result in a smooth transition from magma-poor to magma-rich rifting over hundreds of kilometers. We suggest that the abruptness of the transition results from the development of three-dimensional (3-D) melt migration due to along-strike variations in extension and thus the thickness of the lithosphere at the time of rifting. Localized magmatic addition attributed to melt focusing has been observed in modern mid-ocean ridges and active rift environments, but here we show that such processes can also produce abrupt along-strike changes from magma-poor to magma-rich rifting.
0091-7613
7-10
Shillington, Donna J.
e53cb591-7124-4886-88a5-1b92f65fb199
Scott, Caroline L.
dc4c2116-bf4a-4164-91b4-df93589e8a04
Minshull, Timothy A.
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Edwards, Rosemary A.
e733909a-1bd5-4302-ad8d-61e811b9d8fe
Brown, Peter J.
29f4e81e-e0c4-4147-984b-0215571fb2ca
White, Nicky
e2df0d62-aa85-491e-bb99-ec0aff13b94e
Shillington, Donna J.
e53cb591-7124-4886-88a5-1b92f65fb199
Scott, Caroline L.
dc4c2116-bf4a-4164-91b4-df93589e8a04
Minshull, Timothy A.
bf413fb5-849e-4389-acd7-0cb0d644e6b8
Edwards, Rosemary A.
e733909a-1bd5-4302-ad8d-61e811b9d8fe
Brown, Peter J.
29f4e81e-e0c4-4147-984b-0215571fb2ca
White, Nicky
e2df0d62-aa85-491e-bb99-ec0aff13b94e

Shillington, Donna J., Scott, Caroline L., Minshull, Timothy A., Edwards, Rosemary A., Brown, Peter J. and White, Nicky (2009) Abrupt transition from magma-starved to magma-rich rifting in the eastern Black Sea. Geology, 37 (1), 7-10. (doi:10.1130/G25302A.1).

Record type: Article

Abstract

The amount of magmatism that accompanies the extension and rupture of the continental lithosphere varies dramatically at rifts and margins around the world. Based on widely spaced geophysical transects, some margins are known to preserve a transition from magmatically robust to magmatically starved rifting along strike, but the nature of the transition is unknown. Wide-angle seismic data from the Black Sea provide the first direct observations of such a transition and show that it is abrupt, occurring over only ~20–30 km, and coincides with a transform fault. This abrupt transition cannot be explained solely by gradual along-margin variations in mantle properties, since these would be expected to result in a smooth transition from magma-poor to magma-rich rifting over hundreds of kilometers. We suggest that the abruptness of the transition results from the development of three-dimensional (3-D) melt migration due to along-strike variations in extension and thus the thickness of the lithosphere at the time of rifting. Localized magmatic addition attributed to melt focusing has been observed in modern mid-ocean ridges and active rift environments, but here we show that such processes can also produce abrupt along-strike changes from magma-poor to magma-rich rifting.

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Published date: January 2009
Organisations: Ocean and Earth Science, National Oceanography Centre,Southampton

Identifiers

Local EPrints ID: 65086
URI: http://eprints.soton.ac.uk/id/eprint/65086
ISSN: 0091-7613
PURE UUID: 12cff42e-6bd8-4f51-bc1b-2ca708bb83d2
ORCID for Timothy A. Minshull: ORCID iD orcid.org/0000-0002-8202-1379

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Date deposited: 30 Jan 2009
Last modified: 16 Mar 2024 03:11

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Contributors

Author: Donna J. Shillington
Author: Caroline L. Scott
Author: Rosemary A. Edwards
Author: Peter J. Brown
Author: Nicky White

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