Rayleigh distillation models are developed to describe theoretical growth zoning of Lu, Hf, Rb, Sr, Sm, and Nd in typical garnet crystals from metapelites and metabasites. Effects of diffusion-limited transport within the matrix and intracrystalline diffusion are also considered qualitatively. Theoretical zoning profiles show strong depletions of Lu in garnet rims compared to cores, but virtual...

Pumice samples from Fukutoku-oka-no-ba in the Izu±Bonin ± Mariana (IBM) arc were analysed for 40 trace elements and Sr, Nd, and Pb isotopic compositions. These samples are shoshonites (59.4±61.8 wt% SiO2), characterized by high contents of K2O (3.74±4.64 wt%), Ba (1274±1540 p.p.m.), Rb (91±105 p.p.m.), and light rare earth elements. The characteristics of alkali-element enrichment are similar t...

[1] Strontium and neodymium radiogenic isotope ratios in early to middle Eocene fossil fish debris (ichthyoliths) from Lomonosov Ridge (Integrated Ocean Drilling Program Expedition 302) help constrain water mass compositions in the Eocene Arctic Ocean between !55 and !45 Ma. The inferred paleodepositional setting was a shallow, offshore marine to marginal marine environment with limited connect...

We report Sr isotope anomalies in two Ca·Al-rich inclusions (EKl-4-1 and Cl) of the Allende meteoritewhichalsocontainanomaliesin 0, Mg, Ca, Ba, Nd and Sm. The Sr effects correspond to 84 Sr or 88 Sr deficits of 3.2"too and 0.8%o or to 86 Sr excesses of 1.6%o and 0.4"too. Although it cannot be ascertained in which isotope the anomalies reside, arguments based on the 8 7 Sr abundance indicate tha...

Abstract New geochemical data, including Sr–Nd–Pb isotopes for whole-rock and groundmass samples, are reported edifice-forming eruptives at Tongariro volcano, Zealand, which span its ~ 350 ka to late Holocene history. medium-K basaltic-andesites dacites (53.0–66.2 wt% SiO 2 ) that evolved via assimilation-fractional crystallisation (AFC) processes partly or mostly in the uppermost 15 km of crus...

Recent (<5 Ma) Hawaiian volcanoes define two sub-parallel spatial trends, Loa and Kea. Despite the short distance ( 30 km) between adjacent volcanoes on these trends, most of the Loa-trend shield lavas are geochemically distinct from most of the Kea-trend shield lavas. These geochemical differences arise from small amounts of the LOA component in the source of Loa-trend shield lavas. This compo...

Neodymium strontium manganese oxide with ideal composition Nd(0.5)Sr(0.5)MnO(3) was reported to have two different structure models. In one model, the x coordinate of an O atom is at x > 1/2, while in the other model the x-coordinate of this atom is at x < 1/2. Difference-density maps around this O atom obtained from the current redetermination clearly show that the structure with the O atom at...