نتایج جستجو برای: gabbro

تعداد نتایج: 566  

Journal: :Contributions to Mineralogy and Petrology 2021

Abstract Plagioclase hosted needle- and lath-shaped magnetite micro-inclusions from oceanic gabbro dredged at the mid-Atlantic ridge 13° 01–02? N, 44° 52? W were investigated to constrain their formation pathway. Their genesis is discussed in light of petrography, mineral chemistry, new data transmission electron microscopy (TEM). The show systematic crystallographic shape orientation relations...

Journal: :Remote Sensing 2022

This study evaluates the geological attributes of rocks within Abu Ghalaga area using spatial, geochemical, and petrographic approaches. ASTER Landsat imagery processed band ratio principal component analysis were used to map hydrothermal alterations, while a regional tectonic evaluation was based on automated extraction lineaments from digital elevation model. Geochemical analyses then employe...

Journal: :Geodinamika i Tektonofizika 2022

The current study presents the integration between field observations and remotely sensed data for detection extraction of geological structural features using Sentinel-2A Aster DEM images. area under investigation is represented by Neoproterozoic East African Orogeny encompassing a part Arabian Nubian Shield. All rock units studied belong to Late Cryogenian-Ediacaran periods that are divided i...

ژورنال: :پژوهش های دانش زمین 0
فاطمه سرجوقیان دانشگاه کردستان علی کنعانیان دانشگاه تهران

منطقه قوشچی‏‎ٌ در شمال غرب ایران شامل طیف وسیع سنگ شناسی از گابرودیوریت تا آلکالی گرانیت است که در بخش هایی در هم نفوذ کرده و حجم های مختلفی از آنکلاوهای مافیک را شکل داده و یا در برخی موقعیت ها با هم ادغام شده و سنگ حدواسط را تشکیل داده است. آنکلاوهای موجود با ترکیب سنگ شناسی گابرودیوریت دانه ریز بوده، به طوری که با نزدیک شدن به حاشیه آنکلاو ریز دانه تر شده و براثر تجمع کانی های مافیک در حاشیه ...

2002
G. L. Dawson C. I. Godwin G. E. Ray J. Hammack D. Bordin

features of the area. Sills of hornblende-porphyritic clioritc, are part of the Hedley Intrusive suite believed to bc Latf Triassic or Early Jurassi.: (199 Ma based on U-Pb dates 0 ' zircons from the Banbury stock, 3.5 kilometres west o' Hedley). In this location the sills, which vary.from I to 2f' metres in thickness, make up almost 50 per cent '3f thl: stratigraphic column whtxe they intrude ...

2015
Matthew R. S. Hodgkinson Alexander P. Webber Stephen Roberts Rachel A. Mills Douglas P. Connelly Bramley J. Murton

The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13 km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, hydrothermal precipitates at the VDVF comprise 85-90% by volume of the magnesium silicate mineral, talc. Hydrothermal fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 21...

2016

ONE petrological approach to upper mant le studies is to determine which ultramafic rocks represent mantle material. Ultramafic rocks occur in a variety of field and petrographic associations : in recent reviews, Wyllie [1967b, 1968] outlined eleven petrographic associations, some with subdivisions. In this summary, it is convenient to consider these in four larger groups: (1) layered, stratifo...

Journal: :Geological Quarterly 2023

Regional tectonic synthesis suggests that a segment of the bipartite eastern Gondwana-type Carpathian-Balkan nappe-stacked Getic/Kučaj/Supragetic basement (eastern Serbia) experienced Cambro-Ordovician Cenerian (Sardic) accretionary-type deformation. The Ordovician Alpine Getic/Kučaj nappe exposes an earlier-mapped shallow-marine transgressive-type Fe-silicate-rich ironstone sequence. is used a...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید