The 2.0 Ga pseudo-isochron age inferred from the mid-ocean ridge basalt 207Pb/204Pb against 206Pb/204Pb diagram is re-examined on the basis of a statistical box model of mantle processes. Simple equations are presented which relate the pseudo-isochron age to the decay constants and distribution of heterogeneity ages in the model mantle. In turn this age distribution is simply related to the his...

Abstract The magmatic character of early subduction zone and arc development is unlike mature systems. Low-Ti-K tholeiitic basalts boninites dominate the Izu-Bonin-Mariana (IBM) system. Basalts recovered from Amami Sankaku Basin (ASB), underlying located west IBM’s oldest remnant arc, erupted at ~49 Ma. This was 3 million years after inception (51-52 Ma) represented by forearc basalt (FAB), tip...

[1] Spirit’s Mössbauer (MB) instrument determined the Fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the Gusev plains and the Columbia Hills (West Spur, Husband Hill, Haskin Ridge, northern Inner Basin, and Home Plate) on Mars. The plains are predominantly float rocks and soil derived from olivine basalts. Outcrops at West Spur and on Husband Hill have expe...

[1] Spirit’s Mössbauer (MB) instrument determined the Fe mineralogy and oxidation state of 71 rocks and 43 soils during its exploration of the Gusev plains and the Columbia Hills (West Spur, Husband Hill, Haskin Ridge, northern Inner Basin, and Home Plate) on Mars. The plains are predominantly float rocks and soil derived from olivine basalts. Outcrops at West Spur and on Husband Hill have expe...

[1] We report highly variable mid-ocean ridge basalt (MORB) major element and water concentrations from a single 1050-km first-order spreading segment on the ultraslow spreading Southwest Indian Ridge, consisting of two supersegments with strikingly different spreading geometry and ridge morphology. To the east, the 630 km long orthogonal supersegment (<10 obliquity) dominantly erupts normal MO...

The transfer (accretion) of materials from a subducting oceanic plate to a subduction-accretionary complex has produced rock assemblages recording the history of the subducted oceanic plate from formation to arrival at the trench. These rock assemblages, comprising oceanic igneous rocks progressively overlain by pelagic sedimentary rocks (chert and/or limestone) and trench-fill clastic sediment...

This paper focuses on acoustic reflectivity of the ocean bottom, and describes inversion of reflection data from an experiment designed to study the physical properties and structure of the ocean bottom. The formalism of Bayesian inference is reviewed briefly to establish an understanding of the approach for inversion that is in widespread use. A Bayesian inversion of ocean bottom reflection co...

The contents of seven major components (TiO2, Fe2O3, MgO, CaO, Na2O, K2O and P2O5) and 15 trace elements (Sc, V, Cr, Ni, Cu, Sr, Y, Zr, Ba, La, Ce, Nd, Eu, Yb and Th) were determined by ICP-AE spectrometry in 27 samples of manganese nodules, micronodules as well as abyssal clay collected by dredging from an area of nearly 1,9802 nautical miles in the central Clarion-Clipperton abyssal plain at ...

Noble gas concentrations and isotopic compositions have been measured in eight samples of pillow basalt glasses collected from seven different localities along 250 km of the Mariana Trough spreading and rifting axis. The samples have uniform and mid-ocean ridge basalt (MORB)-like He/He values of 9±12 ́ 10 (6.4±8.6 times atmospheric) despite large variations in He. Concentrations of the noble ga...

Deep reservoirs of water incorporated as hydroxyl into solid silicate minerals of the Earth’s interior may contain the majority of the planet’s hydrogen and have acted as buffers to maintain ocean volume and continental freeboard over geologic time. Two tenths of one weight percent H2O in subducted oceanic crustal material and subsequently released to the hydrosphere from mid-ocean ridge basalt...