|Mariana Trough basalts (MTB): Trace element and Sr-Nd isotopic evidence for mixing between MORB-like and arc-like melts|
Volpe, A.M.; Macdougall, J.D.; Hawkins, J.W. (1987). Mariana Trough basalts (MTB): Trace element and Sr-Nd isotopic evidence for mixing between MORB-like and arc-like melts. Earth Planet. Sci. Lett. 82(3-4): 241-254
In: Earth and Planetary Science Letters. Elsevier: Amsterdam. ISSN 0012-821X, more
Basalts; Geochemistry; Island arcs; Isotopes; ISEW, Mariana Trench [Marine Regions]; Marine
|Authors|| || Top |
- Volpe, A.M.
- Macdougall, J.D.
- Hawkins, J.W.
Mariana Trough basalt (MTB) glasses from zones of active seafloor valcanism have incompatible trace element compositions which are intermediate between normal major ocean ridges basalt (MORB) and basaltic rocks from the active northern Mariana Island Arc (MIAB). The chemical variation is observed in trace elemental abundances and ratios such as LIL/LIL and LIL/HFS. MTB glasses with high LIL/HFS and Ba/Sm ratios, and low K/Rb, K/Ba, and Sm/Nd ratios have more enriched Sr and Nd isotopic compositions. Comparison of the Sr-Nd isotopic compositions of MTB and MIAB suggests that the source region within the mantle wedge is heterogeneous. The diverse trace element and isotopic compositions of MTB glasses both within and between dredge sites near 18 degree N imply small-scale source heterogeneity. Correlation between Sm/Nd and super(143)Nd/ super(144)Nd of the MTB glasses is interpreted as due to recent binary mixing, rather than closed system evolution of a common homogeneous source.