نتایج جستجو برای: gabbro
تعداد نتایج: 566 فیلتر نتایج به سال:
The chemical, morphological and mineralogical properties of two Enon sandy loam (fine, mixed, thermic Ultic Hapludalfs) soilsaprolite profiles, one formed on gabbro and the other on metagabbro, are compared. Clay skins are scarce and stress cutans common in the argillic horizons of these soils. Iron-manganese concretions are concentrated in soil horizons immediately above the argillic horizons....
The petrological features of scoria samples and enclosed holocrystalline xenoliths from the last ~1000 years activity La Soufrière volcano St. Vincent (Lesser Antilles) are described in detail here. products investigated prehistoric eruptions (pre-1440, 1440, 1580 CE) relatively homogeneous basaltic andesites (with a paragenesis consisting plagioclase, clinopyroxene, orthopyroxene opaques) comm...
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This article discusses the geochemical and petrological evolution of São José do Campestre granite complex (SJCgr), last Neoarchean plutonic event so far described in massif NE Brazil. We report field, petrographic, zircon U-Pb dating, whole rock mineral chemistry for representative SJCgr samples. Laser ablation data indicate that emplacement took place at 2664 ± 13 Ma. The rocks comprising hav...
افیولیت بیبی مریم بخشی از مجموعه افیولیتی نهبندان، به سن کرتاسه، در بخش شمالی پهنه گسلی نهبندان، شرق ایران، است. سنگ های مافیک این مجموعه شامل بازالت، دیاباز و گابرو هستند. نبود سنگهای دگرگونی رخساره شیستسبز، شیستآبی و آمفیبولیت، فقدان سنگهای کومهای پریدوتیتی با وجود فراوانی پریدوتیتهای گوشتهای، عدم مشاهده گابروی کومهای علیرغم فراوانی گابروی ایزوتروپ، نبود دسته دایکهای دیابازی به صور...
The mantle beneath coastal SE China evolved from enriched to depleted between the Cretaceous and Neogene, although precise timing of this change remains unclear. Here, we focus on a newly discovered Eocene mafic volcanic neck that contains peridotite xenoliths in Fuding area Fujian Province, present new whole-rock Ar–Ar data which indicate flood basalts formed during (ages 38.5 ± 1.2 42.3 2 Ma)...
Early Jurassic U-Pb age is obtained for both foliated and undeformed granites on Horseshoe Island, Antarctic Peninsula. Some microstructures in the granites/orthogneisses indicate high-temperature greenschist or low- to medium-temperature amphibolite facies deformation conditions. Additionally, a Late Cretaceous yielded gabbro intruding deformed granitoids.
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