Haleakala volcano on East Maui, Hawaii, consists of a tholeiitic basalt shield which grades into a younger alkalic series that was followed by a post-erosional alkalic series. Fresh, stratigraphically controlled samples from the three volcanic series were analyzed for major element abundances, Sr and Nd isotopic ratios and trace element (K, Rb, Sr, Ba, Th, Ta, Nb, REE, Hf, Zr, Sc, V, Cr, Co, Ni...

سلج 36 روم 07 / 02 / 94 و يس و دصكي نيمشش يشهوژپ ياروش هسلج تروص 1 . هسلج ليكشت تعاس و خيرات ،زور : زور هبنشود خيرات هب 07 / 02 / 94 هسلج نامز تدم 2 زا تعاس 14 تياغل 16 2 . يدعب هسلج خيرات : 28 / 02 / 94 3 . هسلج ليكشت لحم : يشهوژپ تنواعم رتفد 4 . هسلج رد هدننك تكرش ءاضعا : 1 ناراجشا يلع رتكد 2 رتكد يمولظم يلع رف 3 رفدنمجرا سابع رتكد 4 يرفعج دمحم رتكد يدنره 5 يضاق ديعس رتكد يبرغم ...

A new numerical technique is proposed to study the stochastic resonance (SR) phenomenon. The proposed numerical approach allows to nd characteristics of SR faster than the previous ones. The signal-to-noise ratio and phase shifts for a system of noisy coupled oscillators are simulated. The spatiotemporal synchronization is shown by means of trajectory analysis.

The assumptions of conventional whole-rock and mineral isochron radioisotope dating were tested using a suite of radioisotopes from two Precambrian rocks. Amphibolite from the Beartooth Mountains of Wyoming shows evidence of thorough metamorphism by isochemical processes from andesite by an early Precambrian magma-intrusion event. A diabase sill, exposed within the wall of Grand Canyon at Bass ...

Rainwater and snow collected from three different sites in France (Vosges Mountains, French Alps and Strasbourg) show more or less similar shapes of their REE distribution patterns. Rainwater from Strasbourg is the most REE enriched sample, whereas precipitations from the two mountainous, less polluted catchments are less REE enriched and have concentrations close to seawater. They are all stro...

Boninites are unusual island arc volcanic rocks with high MgO (>9%), high Si0 2 (>55%) contents, and exceptionally low TiO 2 (<0.4%) contents. High MgO contents, MgO/(MgO + EFeO), Ni, Cr and Co contents indicate that boninites have equilibrated with mantle peridotite. Experimental petrologic studies and high Cr/(Cr + Al) in spinels in boninites suggest that they have separated from extremely re...