In the Variscan Western Tatra granites hybridization phenomena such as mixing and mingling can be observed at the contact of mafic precursors of dioritic composition and more felsic granitic host rocks. The textural evidence of hybridization include: plagioclase-K-feldspar-sphene ocelli, hornblende- and biotite-rimmed quartz ocelli, plagioclase with Ca-rich spike zonation, inversely zoned K-fel...

All ten known aubrites (enstatite achondrites) as well as Happy Canyon and Mt. Egerton, related anomalous meteorites, have been studied in order to understand their origin and relationship to enstatite chondrites. Mineralogically, aubrites contain 75-9B% enstatite (En98.76-99.54), 1-16% plagioclase (Anl.S-B.:), O.Z-K.l^r diopside (Wo40.1-46.1). 0.3-10.07f olivine (Fo99.79-99,99), <0.l3.7% metal...

In the Geologists and Miller Ranges of the central Transantarctic Mountains, mafic and ultramalic tectonic blocks occur in an Early Cambrian amphiboliteto granulite-facies lower crustal transpressional shear zone. Mafic blocks consist of garnet + clinopyroxene symplectite + hornblende + plagioclase + quartz + ilmenite f orthopyroxene f biotite;mineral compositions in these blocks generally refl...

Both highand medium-pressure granulites have been found as because of the absence of modal minerals. The combination of petrographic textures, mineral compositions, metamorphic reaction enclaves and boudins in tonalitic–trondhjemitic–granodioritic gneisses in the Hengshan Complex. Petrological evidence from these history, petrogenetic grids and thermobarometric data defines a nearrocks indicate...

Experimental petrology and major element chemistry are used to infer the melting processes that operate in the upper oceanic mantle to yield basaltic magma, and the subsequent cooling processes by which these magmas chill to form the oceanic crust. THE PRIMARY MAGMAS OF MID-OCEAN RIDGE BASALTS This paper reports experiments carried out between 9 and 16 kbar (0.9 1.6 GPa) using natural, primitiv...

Following accretion of southern Siberian microcontinents to the compositions reveal up to one order of magnitude variation of some trace elements and ratios between suites, and show a progressive Siberian craton in the Early Paleozoic, five cycles of K-rich silicic magmatism, progressively decaying in volume, occurred on batholithic change in trace element concentration with decreasing age. Pla...

High precision oxygen three-isotope ratios were measured for four mineral phases (olivine, low-Ca and high-Ca pyroxene, and plagioclase) in equilibrated ordinary chondrites (EOC) using a secondary ion mass spectrometer. Eleven EOCs were studied that cover all groups (H, L, LL) and petrologic types (4, 5, 6), including S1-S4 shock stages, as well as unbrecciated and brecciated meteorites. SIMS a...

Introduction: Melt breccias generated by a bolide collision in the vicinity of Bahía Blanca, Buenos Aries Province, Argentina at the Miocene-Pliocene Boundary (5.28 ± 0.04Ma) contain sand-sized meteoritic clasts [2], reviewed in [1]. The clasts exhibit textures and mineral assemblages (Fig. 1) most similar to quenched volcanic angrites, especially Asuka 881371 and Sahara 99555. They contain aci...

Plagioclase feldspar, clinopyroxene, and ilmenite in a polished thin section of a type A crystalline rock were analyzed. The clinopyroxene grains are compositionally variable, and both high Ca and low Ca phases are present. The plagioclase is compositionally homogeneous. The ilmenite is chemically homogeneous except for occasional, small areas of high local chromium concentration. Accessory min...

Coupled thermal–orbital histories of early lunar evolution are considered in a simple model. We consider a plagioclase lid, overlying a magma ocean, overlying a solid mantle. Tidal dissipation occurs in the plagioclase lid and heat transport is by conduction and melt migration. We find that large orbital eccentricities can be obtained in this model. We discuss possible consequences of this phas...