• journal_title：Geology
• Contributor：S. Fretzdorff ; K.M. Haase ; P.T. Leat ; R.A. Livermore ; C.-D. Garbe-Schönberg ; J. Fietzke ; P. Stoffers
• Publisher：Geological Society of America
• Date：2003-
• Format：text/html
• Language：en
• Identifier：10.1130/G19469.1
• journal_abbrev：Geology
• issn：0091-7613
• volume：31
• issue：8
• firstpage：693

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.