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The three layered intrusions studied in the Laouni area have been emplaced within syn-kinematic Pan-African granites and older metamorphic rocks. They have crystallized at the end of the regional high-temperature metamorphism, but are free from metamorphic recrystallization, revealing a post-collisional character. The cumulate piles can be interpreted in terms of two magmatic liquid lines of descent:...
The Neogene volcanic province of SE Spain (NVPS) is characterized by calc-alkaline (CA), high-K calc-alkaline (KCA), shoshonitic (SH), ultrapotassic (UP), and alkaline basaltic (AB) volcanic series. All these series, except the AB, have high LILE/LREE, LILE/HFSE and B/Be ratios and high but variable Sr, Pb and O isotope compositions. The KCA and SH lavas contain metapelitic xenoliths whose mineralogical...
Calc-alkaline magmatism in the south-west Ukraine occurred between 13.8 and 9.1 Ma and formed an integral part of the Neogene subduction-related post-collisional Carpathian volcanic arc. Eruptions occurred contemporaneously in two parallel arcs (here termed Outer Arc and Inner Arc) in the Ukrainian part of the Carpathians. Outer Arc rocks, mainly andesites, are characterized by LILE enrichment (e...
The stable isotope composition (O,H) of whole-rock and mineral separates of Cambrian-Ordovician gabbros, diorites, granodiorites and granites forming the Mt. Abbott composite intrusions (Northern Victoria Land, Antarctica) was measured to constrain the origin and evolution of the magmas postdating the Ross Orogen. The δ 18 O values of olivine gabbros plot in the field of slightly evolved...
Three xenoliths erupted as ejecta during recent violent explosion of Stromboli volcano (Aeolian Islands) were investigated in this paper. They consist of high-temperature mineral association (cordierite, hercynite spinels, sillimanite, ±plagioclase, ±mullite, ±corundum) and abundant glass (10–70 vol.%), and may be classified as buchites. The peraluminous composition of the xenoliths, their trace element...
New major and trace element analyses and Sr-isotope determinations of rocks from Mt. Somma–Vesuvius volcano produced from 25 ky BP to 1944 AD are part of an extensive database documenting the geochemical evolution of this classic region. Volcanic rocks include silica undersaturated, potassic and ultrapotassic lavas and tephras characterized by variable mineralogy and different crystal abundance, as...
The Geysers geothermal reservoir in the California Coast Ranges is the world's largest economically used geothermal system. Surface exposure of volcanic rocks and extensive drill penetration of a >300 km 3 subsurface plutonic body (Geysers Plutonic Complex or GPC) that underlies the reservoir allow unique insights into the evolution of a volcanic–plutonic magma system. We present compositional...
A variety of high Ba–Sr granites and syenites is intruded into the Caledonian terrane of the Northern Highlands of Scotland. Volumetrically rather small, the plutons display a considerable range of compositions from ultramafic and mafic to granitic and syenitic. Most intrude Proterozoic Moine metasediments, though some are exposed within the Moine Thrust Zone in the west, beyond which lies the Archaean...
We present 104 whole-rock geochemical analyses of hypabyssal kimberlite from the Lac de Gras field. Screens using Yb versus Al 2 O 3 and ln Si/Al versus ln Mg/Yb effectively discriminate crustally contaminated samples. The remaining “non-contaminated” kimberlites samples have variable (5 to 50%) entrainment of cratonic peridotite. It is problematic to effectively screen for small amounts...
Mafic–ultramafic layered intrusions align along a N–S trending fault zone in the central part of the late Permian Emeishan large igneous province, SW China. We present major and trace element and clinopyroxene Sr, Nd, Pb and O isotopic compositions of three representative mafic–ultramafic layered intrusions, the Panzhihua gabbro intrusion that hosts V–Ti–Fe ores, the Limahe peridotite intrusion that...
In the Huangling region of the northern Yangtze Block, South China, the 820-Ma Huangling felsic pluton was intruded by ∼800-Ma mafic dikes. These dikes are composed of fine- to medium-grained diabase, porphyritic diabase and olivine gabbro. Quartz xenocrysts occur locally in the olivine gabbro. The rocks are alkaline to sub-alkaline in composition and have SiO 2 ranging from 43.3 to 57.2wt...
Pb isotopic data are presented for hybrid rocks formed by mingling between mantle-derived tholeiitic magma of the Eocene Miki Fjord macrodike (East Greenland) and melt derived from the adjacent Precambrian basement. Bulk mixing and AFC processes between end-members readily identified in the field fail to model the Pb isotope systematics. Selective contamination during diffusional exchange, which can...
The Baima mafic–ultramafic layered intrusion of the 260-Ma Emeishan Large Igneous Province (ELIP) hosts the second largest Fe–Ti–(V) oxide deposit in the Panxi region, SW China. It is a ~1600-m-thick layered body intruded by slightly younger syenitic and granitic plutons. The intrusion includes the Lower and Upper Zones. Troctolite and olivine pyroxenite of the Lower Zone contains conformable oxide...
The petrogenesis of the Kerforne dyke tholeiitic basalts (Brittany, France), the northernmost outcrop of the 200Ma Central Atlantic magmatic province (CAMP), is constrained by its zoned augite and plagioclase crystals. Augite cores with high Mg/Fe and Cr suggest crystallization from near-primary magmas, with slightly enriched Rare Earth element (REE) patterns. Plagioclase crystals with high-An (An...
The Tarim continental flood basalts (CFBs) provide important clues about the genesis and magmatic evolution of the Early Permian Tarim Large Igneous Province (Tarim LIP) in northwestern China. Here we present results of LA–MC–ICPMS Lu–Hf isotope analysis on Early Permian (ca. 290Ma) zircons extracted from the Tarim CFBs in the Keping area, northwest of the Tarim Basin. Zircons from two sub-groups...
The presented Sr, Nd, Hf and double-spike Pb-isotopic analyses of Quaternary basalts from the Payenia volcanic province in southern Mendoza, Argentina, confirm the presence of two distinct mantle types feeding the Payenia volcanism. The southern Payenia mantle source feeding the intraplate-type Río Colorado and Payún Matrú volcanism is isotopically distinct from the northern Payenia and arc mantle...
Continental basalts have complicated petrogenetic processes, and their chemical compositions can be affected by multi-staged geological evolution. Compared to lithophile elements, chalcophile elements including Ni, platinum-group elements (PGEs) and Cu are sensitive to sulfide segregation and fractional crystallization during the evolution of mantle-derived magmas and can provide constraints on the...
The two main magmatic properties associated with explosive eruptions are high viscosity of silica-rich magmas and/or high volatile contents. Magmatic processes responsible for the genesis of such magmas are differentiation through crystallization, and crustal contamination (or assimilation) as this process has the potential to enhance crystallization and add volatiles to the initial budget. In the...
Upper Paleozoic (~365Ma) mafic and intermediate volcanic rocks of the Piskahegan Group constitute a subordinate part of the Mount Pleasant caldera, which is associated with a significant polymetallic deposit (tungsten–molybdenum–bismuth zones ~33Mt ore with 0.21% W, 0.1% Mo and 0.08% Bi and tin–indium zones ~4.8Mt with 0.82% Sn and 129g/t In) in southwestern New Brunswick (Canada). The epicontinental...
The tectonic and geodynamic setting of the southern Central Andean convergent margin changed significantly between the Late Cretaceous and the Late Miocene, influencing magmatic activity and its geochemical composition. Here we investigate how these changes, which include changing slab-dip angle and convergence angles and rates, have influenced the contamination of the arc magmas with crustal material...
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