نتایج جستجو برای: ocean ridge basalt

تعداد نتایج: 82934  

Journal: :Open Journal of geology 2022

Within southern Mali, the Syama belt constitutes a linear major structure-oriented N-S, which host several gold deposits (e.g., and Tabakoroni) prospect areas (e.g. Tellem). The Belt is formed by magmatic rocks (basalts, lamprophyres, andesites, dacites microgranites); sedimentary (shales) volcano-sedimentary (pyroclastics). are divided into two main volcanic series: tholeiitic affinity (basalt...

2012
Debra M. Hurwitz James W. Head Lionel Wilson Harald Hiesinger Rima Prinz

[1] Lunar sinuous rilles have long been interpreted as features that formed as the result of surficial lava flow, though the precise mechanism responsible for channel formation (constructed versus eroded origins) is still debated. In assessing the origin of Rima Prinz, a channel interpreted to have formed by erosion, two erosion regimes, mechanical and thermal, are considered. Measurements of c...

2016
RICHARD SEAGER NAOMI HENDERSON

The causes of the high pressure ridge at the North American west coast during winter 2013/14, the driest winter of the recent California drought, are examined. The ridge was part of an atmosphere–ocean state that included anomalies, defined relative to a 1979–2014 mean, of circulation across the Northern Hemisphere, warm sea surface temperatures (SSTs) in the tropical western and northeastern P...

ژورنال: :بلورشناسی و کانی شناسی ایران 0
مرتضی دلاوری department of geology, faculty of science, tarbiat moallem university, tehran.تهران، دانشگاه تربیت معلم تهران، دانشکده علوم، گروه زمین شناسی صدرالدین امینی department of geology, faculty of science, tarbiat moallem university, tehran.تهران، دانشگاه تربیت معلم تهران، دانشکده علوم، گروه زمین شناسی امیلیو ساکانی department of geology, faculty of science, university of ferrara, ferrara, italyایتالیا، فرارا، دانشگاه فرارا، دپارتمان علوم

معدن بندان اصلی ترین ذخیره­ی کرومیتی در زون جوش خورده­ی سیستان (شرق ایران) است. توده های کرومیتی به­صورت ساختارهای ورقه ای تا عدسی شکل تظاهر داشته و با پریدوتیت­های گوشته ای بیشتر دونیتی تا هارزبورژیتی میزبانی می شوند. رابطه­ی کرومیتیت- سنگ میزبان مشابه با کرومیت­های نوع آلپی با حضور یک غشای دونیتی پیرامون توده های کرومیتی مشخص می شود. کرومیت­ها بیشتر بافت توده­ای تا افشان و نیز برشی دارند. شیم...

Journal: :Geophysical Research Letters 2021

Oxyhydroxides like δ-(Al,Fe)OOH may stabilize “water” in Mid-Ocean Ridge Basalt (MORB) subducted into the Earth's lower mantle. The single-crystal elasticity of has not been experimentally constrained, hampering an accurate evaluation seismic detectability this high-pressure solid solution, and presence “water,” deep Earth. Here, we report first experimental results δ-(Al0.97Fe0.03)OOH measured...

2007
Ikuo Kushiro

Studies of the origin of magmas in subduction zones, particularly in the Japanese island arc, have been significantly advanced by petrological, geochemical, geophysical and experimental studies during last 50 years. Kuno's original model(1)) for magma generation in the Japanese island arc, that tholeiite magmas are formed at relatively shallow levels in the mantle on the Pacific Ocean side wher...

2009
B. Bourdon T. Kleine F. Oberli B. Reynolds

The silicon isotope composition of three carbonaceous chon-drites (Orgueil, Murchison, and Vigarano), three ordinary chon-drites (Parnallee, Bovedy, Bremervörde), one enstatite chondrite (Sahara 97158) and nine terrestrial samples (7 peridotites, 1 mid-ocean ridge basalt, 1 ocean island basalt) were measured to high precision and accuracy using the high resolution Nu Plasma 1700 MC-ICPMS at ETH...

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