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230Th-238U disequilibrium in East Scotia back-arc basalts: implications for slab contribution and flux rates.
Fretzdorff, Susanne, Haase, Karsten, Leat, P. T., Livermore, R. A., Garbe-Schönberg, C.-Dieter, Fietzke, Jan and Stoffers, Peter (2003) 230Th-238U disequilibrium in East Scotia back-arc basalts: implications for slab contribution and flux rates. Geology, 31 (8). pp. 693-696. DOI 10.1130/G19469.1.
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Abstract
New U-series isotope data for lavas from the East Scotia backarc spreading center span a large range in (230Th/232Th) and (238U/232Th). Most of the backarc lavas have (238U/230Th) < 1, similar to the composition of mid-oceanic-ridge basalts (MORB). Lavas from two segments have (238U/230Th) > 1 and are enriched in fluid-mobile elements, implying a recent addition of a U-rich slab-derived component. The data from one segment suggest an influence from an aqueous fluid from altered MORB, whereas samples from the other slab-influenced segment show addition of a sediment melt. The slab-influenced samples form a distinct trend in the equiline diagram between aqueous fluid and sediment melt that is suggested to be a mixing line rather than an isochron.
Document Type: | Article |
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Keywords: | East Scotia Ridge, backarc, U-series isotopes, aqueous fluids, sediment melts |
Research affiliation: | Kiel University |
Refereed: | Yes |
Open Access Journal?: | No |
Publisher: | GSA, Geological Society of America |
Date Deposited: | 18 Feb 2008 17:26 |
Last Modified: | 26 Sep 2017 07:58 |
URI: | https://oceanrep.geomar.de/id/eprint/5126 |
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