نتایج جستجو برای: volcanic arc granitoid

تعداد نتایج: 50524  

Journal: :زمین شناسی اقتصادی 0
ملیحه قورچی روکی محمد حسن کریم پور جی لنگ فارمر چارلز استرن

the halak abad prospect occurs in the northeastern part of central iran zone (sabzevar structural zone). in this investigation, geochemical evolution, age and source of part of northeastern iran magmatic arc (intrusive bodies) in halak abad area in the khorasan razavi province has been studied. the exposed rocks consist of volcanic rocks with andesite and dacite nature, limestone, plutonic rock...

2002
Mihai N. Ducea

[1] Garnet pyroxenites are the most common deep lithospheric xenolith assemblages found in Miocene volcanic rocks that erupted through the central part of the Sierra Nevada batholith. Elemental concentrations and isotope ratios are used to argue that the Sierra Nevada granitoids and the pyroxenite xenoliths are the melts and the residues/cumulates, respectively, resulting from partial melting/f...

2013
G. Jacques K. Hoernle J. Gill F. Hauff H. Wehrmann D. Garbe-Schönberg P. van den Bogaard I. Bindeman L. E. Lara

Crustal assimilation (e.g. Hildreth and Moorbath, 1988) and/or subduction erosion (e.g. Stern, 1991; Kay et al., 2005) are believed to control the geochemical variations along the northern portion of the Chilean Southern Volcanic Zone. In order to evaluate these hypotheses, we present a comprehensive geochemical data set (major and trace elements and O–Sr–Nd–Hf–Pb isotopes) from Holocene primar...

2003
P. NEUMAYR

Abst rac t -Large parts of the Central Eastern Desert of Egypt consist of Neoproterozoic nappes of ophiolite and island-arc volcanic rocks. Beneath these nappes metamorphic basement domes are exposed in tectonic w indows such as the Meatiq basement. The mineral and whole rock chemistry of amphibol i tes included in the teconical ly lowermost granitoid gneiss, within the metasedimentary cover of...

سعادت, سعید, مظاهری, سید احمد, مظهری, مریم سادات, همام, سید مسعود,

The study area is located in Tertiary plutonic belt of Lut Block.  Tertiary intrusive injection in Cretaceous limestone caused the formation of skarn in this region. Injection intrusive changes the texture and mineralogy of limestone and skarn or marble formed. A lens-shaped iron mineralization mainly occurred in the border of intrusions and calcareous unit. Petrological studies show that the w...

2013
R J Hein

Introduction Hydrothermal systems and their associated metal deposits have been studied at oceanic spreading centers since the late 1970s when they were first discovered. More recently, those studies have been extended to subduction zone hydrothermal systems including active volcanic arcs and back-arc environments. Oceanic spreading centers compose a global ridge system where new ocean crust is...

Journal: :geopersia 2011
amir esna-ashari mohammad vali valizadeh abolfazl soltani ali asghar sepahi

the aligoodarz granitoid occurs in sanandaj-sirjan zone (ssz), western iran. tonalite, granodiorite and granite are the main rock types cropping out in the area. comparison of aligoodarz granitoid with dehno and boroujerd granitoids reveals several similarities in their chemical characteristics. thus, the above mentioned granitoids can be assigned as a co-genetic magmatic suite, in which pluton...

2017
David W Farris Agustin Cardona Camilo Montes David Foster Carlos Jaramillo

Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21-25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile e...

2001
Alfred Hochstaedter Jim Gill Robert Peters Phil Broughton Pete Holden Brian Taylor

[1] Abstract: We propose that across-arc differences in the geochemistry of Izu-Bonin arc magmas are controlled by the addition of fertile-slab fluids to depleted mantle at the volcanic front, and residual-slab fluids to fertile mantle in the back arc without slab melting or contemporaneous back arc spreading. The arc consists of a volcanic front, an extensional zone, and seamount chains (the W...

Journal: Geopersia 2014

Three intrusive granitoid bodies from northwest Saveh, central Iran, are embedded in volcanic sedimentary rocks of the Eocene,forming isolated small outcrops: Khalkhab quartz monzodioritic units (SiO2: ~52-57 wt %) to the northwest, Neshveh granodioriticunits (SiO2: ~62-71 wt %) to the northeast, and Selijerd granodioritic units (SiO2: ~63-69 wt %) to the southeast. The Khalkhab unit iscomposed...

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