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The Western Iratsu body of the Sanbagawa belt (SW Japan) represents a <2km thick garnet–epidote amphibolite slice with minor intercalated occurrences of eclogite. Equilibrium phase assemblage diagrams (pseudosections) for eclogite and garnet–epidote amphibolite from this body can be successfully used to reconstruct the pressure (P)–temperature (T) path and the evolution of the associated mineral...
A high-resolution U–Pb zircon geochronological study of plutonic units along the south Peruvian margin between 17° and 18°S allows the integration of the geochemical, geodynamic and tectonic evolution of this part of the Andean margin. This study focuses on the composite Jurassic–early Cretaceous Ilo Batholith that was emplaced along the southern Peruvian coast during two episodes of intrusive magmatism;...
The late Carboniferous to Permian is a critical period for final amalgamation of the Central Asian Orogenic Belt (CAOB), which is characterized by voluminous igneous rocks, particularly granitoids. The Kekesai composite granitoid porphyry intrusion, situated in the Chinese western Tianshan (southwest part of CAOB) includes two intrusive phases, a monzogranite phase, intruded by a granodiorite phase...
Four Late Pleistocene magnesian andesites (locally called “bajaites”) from Baja California have been dated by the unspiked K–Ar method and analyzed for major, trace elements and Sr, Nd, Pb, Th and U isotopes. They display very large 230 Th excesses (50% to 120%) relative to 238 U. They also have very high Ba and Sr contents and Sr/Y and La/Yb ratios, together with suprachondritic Nb/Ta...
Synorogenic basin development and subsequent collapse and loading provide important constraints on the Late Cretaceous crustal structure of the North America Cordillera. High grade metasedimentary rocks of the Swakane Gneiss in the North Cascades have been interpreted to include ca. 73Ma detrital zircon that requires a protolith age considerably younger than metamorphic ages of adjacent terranes....
We report new data on a suite of compositionally variable igneous rocks intruding amphibolite grade schists and marbles of the Beiarn Nappe Complex of the Uppermost Allochthon, Scandinavian Caledonides, to better understand the pre-collisional position and evolution of this exotic continental terrane within the Scandinavian Caledonides. Major and trace element data on bulk samples combined with U–Pb...
The Cenozoic magmatic record within the ca. 500km long eastern Pontides orogen, located within the Alpine metallogenic belt, is critical to evaluate the tectonic history and geodynamic evolution of the eastern Mediterranean region. In this paper we report for the first time late Miocene adakitic rocks from the southeastern part of the eastern Pontides belt and present results from geochemical and...
Slices of polycyclic metasediments (marbles and meta-cherts) are tectonically amalgamated with the polydeformed basement of the Dent Blanche tectonic system along a major Alpine shear zone in the Western Alps (Becca di Salé area, Valtournenche Valley). A combination of techniques (structural analysis at various scales, metamorphic petrology, geochronology and trace element geochemistry) was applied...
Baksi (2012) claims that a number of radiometric ages presented in Barry et al. (2010) are statistically invalid and that many of the samples were altered, thus not able to date the eruptions, and that there is no compelling evidence for a limited duration for the eruption of the Grande Ronde Basalts (GR Basalts), USA. However, Baksi (2012), has simply reiterated some of the assessment of the data...
This study presents new measurements of Fe 3+ in garnet, olivine, clino- and orthopyroxene of a mantle-derived garnet peridotite from Donghai County, the southeastern end of the Sulu ultrahigh pressure terrane. These rocks correspond to a slice of supra-subduction lithospheric mantle wedge, tectonically emplaced into the crust. They record a multistage metasomatism by an alkali-rich silicate...
Orthogneisses crop out in different lithostratigraphic positions throughout the Nevado-Filábride metamorphic Complex (Betic Cordillera, southern Spain). Their abundance offers the opportunity to establish its origin and to date the ages of acid magmatism and of early deposition ages of metasedimentary host rocks of the orthogneisses, in this complex metamorphosed and deformed during the Alpine Orogeny...
Miocene igneous rocks of the Western Outer Carpathians in Poland and Moravia, Czech Republic, were emplaced in a tectonic setting transitional between the European foreland and the Carpathian–Pannonian arc system. They form medium- to high-K calc-alkaline suites which are compositionally different to each other and to other calc-alkaline sequences in the region. Geographically and compositionally...
The North China Craton is one of the Archean cratons on Earth, and it has been reactivated since the Mesozoic with significant thinning of the subcontinental lithospheric mantle (SCLM). While geophysical observations indicate the effect of the Pacific plate subduction on the westward thinning, the coherent records are also evident from geochemistry of Cenozoic continental basalts in North China. This...
A Late Cretaceous collision of the southernmost portion of the North American continental margin with an undetermined southern block was first established based on the sedimentation history of the plate's supracrustal cover, which is overthrust by harzburgite-dominated nappes of the Guatemala Suture Complex. The collision is also well registered in the metamorphic evolution of continental eclogites...
The Zanhuang complex is located at the eastern margin of the middle segment of the Trans-North China Orogen, along which the Western and Eastern Blocks collided to form the North China Craton. The complex has been divided into the Archean Zanhuang Group and the Paleoproterozoic Gantaohe and Dongjiao Groups. The Gantaohe Group is composed of meta-volcanic rocks, basal conglomerates, meta-tuffaceous...
During geological investigations conducted over the past several years, the authors found a group of A-type granites in the middle segment of the Bangonghu–Nujiang suture on the Tibetan plateau. These granitic plutons occur as stocks with exposed areas of less than 1km 2 and lithologically include biotite granite and granodiorite porphyry, which had intruded into Cretaceous sedimentary rocks...
The late Mesozoic granitoids widely distributed in the northwestern Jiaodong Terrane are important markers of cratonic destruction and lithospheric thinning of the eastern North China Craton (NCC). Here we investigate the Late Jurassic Linglong and Luanjiahe granites and report zircon U–Pb emplacement ages of 157–159Ma. These rocks also contain abundant late Archean, Paleoproterozoic, Neoproterozoic,...
We present new data on spinel peridotite xenoliths hosted in Agardag alkaline lamprophyres from the Sangilen Plateau (Tuva, South Siberia, Russia), sampling at ~450Ma the subcontinental lithospheric mantle of the Tuva-Mongolian micro-continent that belongs to the accretionary Central Asian orogenic belt at the southern edge of the Siberian craton. Xenoliths are spinel lherzolites principally showing...
To contribute to the understanding of magma evolution in arc settings we investigate the oldest volcanic unit (Kanafià Synthem) of Nisyros volcano, located in the eastern Aegean Sea (Greece). The unit consists of porphyritic pillow lavas of basaltic andesite composition with trace element signatures that are characteristic of island-arc magmas. Two lava types are distinguished on the basis of geochemistry...
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