(Table 1) Composition of volcanic glasses from the East Scotia Ridge ...

• Main Authors: Fretzdorff, Susanne, Haase, Karsten M, Leat, Philip, Livermore, Roy A, Garbe-Schönberg, Dieter, Fietzke, Jan, Stoffers, Peter
• Format: Dataset
• Language: English
• Published: PANGAEA 2003
• Subjects: Section; Sample ID; Magnesium oxide; Thorium; Uranium; Uranium-238/Thorium-232 ratio; Error, absolute; Uranium-234/Uranium-238 activity ratio; Thorium-230/Thorium-232 ratio; Thorium-230/Uranium-238 ratio; Rock sample; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas SPP1158; Arctic; Antarctic; East Scotia Ridge; Antarc*; Sea ice
• Online Access: https://dx.doi.org/10.1594/pangaea.847689; https://doi.pangaea.de/10.1594/PANGAEA.847689

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. ... : The quoted errors are 2 sigma errors. ...