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Physical Sciences and Mathematics

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Colby College

Theses/Dissertations

2012

Mantle

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Geodynamic Constraints On The Flow Of Samoan-Plume Mantle Into The Northern Lau Basin, Nathan Katsiaficas Jan 2012

Geodynamic Constraints On The Flow Of Samoan-Plume Mantle Into The Northern Lau Basin, Nathan Katsiaficas

Honors Theses

The northernmost portion of the Lau basin, South Pacific, features numerous geochemical and geophysical anomalies. These include: (1) a strong latitudinal gradient in the trace element and isotopic (Sr-Nd-Pb) enrichment of basalts erupted along the various back-arc spreading centers (BASCs) within the basin, (2) high 3He/4He (up to 28 times RA, where RA, the ratio in Earth's atmosphere, is 1.4 x 10-6) in basalts erupted along some portions of the BASCs (e.g., Rochambeau Bank), and (3) the presence of trench-parallel shear-wave splitting near the Tonga arc. The occurrence of these anomalies has been attributed to the southward flow of mantle …