Tectonic implications of fore-arc magmatism and generation of high-magnesian andesites: Alexander Island, Antarctica

  title={Tectonic implications of fore-arc magmatism and generation of high-magnesian andesites: Alexander Island, Antarctica},
  author={Joe J. McCarron and John L. Smellie},
  journal={Journal of the Geological Society},
  pages={269 - 280}
Alexander Island, situated off the west coast of the Antarctic Peninsula, contains a suite of Late Cretaceous to Early Tertiary subduction-related magmatic rocks. The rocks occupy a fore-arc position 100–200 km trenchward of the main arc (Antarctic Peninsula) and they become younger northward along the length of the island. Major and trace element geochemistry for 222 samples shows the suite to be a medium to high-K calc-alkaline series, ranging in composition from picro-basalt to rhyolite… Expand

Figures from this paper

Magmatic relationships and ages between adakites, magnesian andesites and Nb-enriched basalt-andesites from Hispaniola: Record of a major change in the Caribbean island arc magma sources
Abstract Located in the Cordillera Central of the Dominican Republic, the Late Cretaceous Tireo Fm (TF) records a major change of the magma sources in the Caribbean island arc. It comprises a > 3 kmExpand
Magmatic record of Late Devonian arc-continent collision in the northern Qiangtang, Tibet: Implications for the early evolution of East Paleo-Tethys Ocean
Abstract Recognizing the early-developed intra-oceanic arc is important in revealing the early evolution of East Paleo-Tethys Ocean. In this study, new SIMS zircon U-Pb dating, O-Hf isotopes, andExpand
One or Two Early Cretaceous Arc Systems in the Lhasa Terrane, Southern Tibet
Spatial and temporal variations of arc-related magmatism are key to determining the subduction polarity of incompletely preserved arc systems. Petrographic, geochronological, geochemical, and isotopeExpand
Chapter 3.1b Antarctic Peninsula and South Shetland Islands: petrology
Abstract The Antarctic Peninsula contains a record of continental-margin volcanism extending from Jurassic to Recent times. Subduction of the Pacific oceanic lithosphere beneath the continentalExpand
Petrogenesis and tectonic implications of Early Jurassic volcanic rocks of the Raohe accretionary complex, NE China
Abstract The Raohe accretionary complex, located at the border between the Russian Far East and Northeastern China, is a significant part of the western Pacific Oceanic tectonic regime. Due to lackExpand
Discovery of Latest Cretaceous OIB-type alkaline gabbros in the Eastern Pontides Orogenic Belt, NE Turkey: Evidence for tectonic emplacement of seamounts
Abstract The Meso-Cenozoic geodynamic evolution of the Eastern Pontides Orogenic Belt, a mountain chain extending parallel to the southeastern margin of the Black Sea, has been controversial for theExpand
Underplating of basaltic magmas and crustal growth in a continental arc: Evidence from Late Mesozoic intermediate–felsic intrusive rocks in southern Qiangtang, central Tibet
Abstract Phanerozoic growth of continental crust has widely been considered as an important geological phenomenon and mainly occurs in an arc setting. However, the crustal growth modelsExpand
Simultaneous growth and reworking of the Lhasa basement: A case study from Early Cretaceous magmatism in the north-central Tibet
Abstract Magmatic rocks preserve a lot of information about the formation and evolution of continental crust, and they play an important role in understanding the growth and reworking of ancientExpand
Combined Sr, Nd, Pb and Li isotope geochemistry of alkaline lavas from northern James Ross Island (Antarctic Peninsula) and implications for back-arc magma formation
Abstract We present a comprehensive geochemical data set for a suite of back-arc alkaline volcanic rocks from James Ross Island Volcanic Group (JRIVG), Antarctic Peninsula. The elemental and isotopicExpand
Melting of a subduction-modified mantle source: A case study from the Archean Marda Volcanic Complex, central Yilgarn Craton, Western Australia
Abstract Subduction processes on early earth are controversial, with some suggestions that tectonics did not operate until the earth cooled to a sufficient point around the Archean–ProterozoicExpand


The age and stratigraphy of fore-arc magmatism on Alexander Island, Antarctica
Fore-arc magmatic sequences associated with high Mg number andesite lavas unconformably overlie LeMay Group accretionary complex in Alexander Island. High-resolution 40Ar/39Ar, U–Pb zircon, fissionExpand
Geochemistry of Cenezoic volcanic rocks, Baja California, Mexico: Implications for the petrogenesis of post-subduction magmas
Abstract Late Cenozoic volcanism in Baja California records the effects of cessation of subduction at a previously convergent, plate margin. Prior to 12.5 m.y., when subduction along the margin ofExpand
A unifying lithostratigraphy of late Cretaceous–early Tertiary fore-arc volcanic sequences on Alexander Island, Antarctica
Late Cretaceous–early Tertiary subduction-related fore-arc volcanic rocks are exposed in a north–south linear belt along the length of Alexander Island. The age and tectonic setting of these rocks isExpand
Geochemistry of mafic dykes in the Antarctic Peninsula continental-margin batholith: a record of arc evolution
Mafic dykes of the Antarctic Peninsula continental-margin arc are compositionally diverse, comprising calc-alkaline (dominant), shoshonite, tholeiite, and OIB-like varieties. Their compositions giveExpand
Peraluminous granites in NE Palmer Land, Antarctic Peninsula: early Mesozoic crustal melting in a magmatic arc
A suite of Early Jurassic metaluminous to strongly peraluminous granitoids occupy a rear-arc position in Palmer Land, Antarctic Peninsula with respect to a Mesozoic–Cenozoic magmatic arc. FractionalExpand
Plate-tectonic model for southern Antarctic Peninsula and its relation to southern Andes
Three main Upper Jurassic–Cretaceous tectono-stratigraphic units recognized in Palmer Land and Alexander Island are comparable with assemblages formed (1) in an ensialic volcanic arc (Upper JurassicExpand
On the Tectonic Significance of Arc Volcanism in Northern Kamchatka
The Vyvenka volcanic field records a period of Neogene, subduction-related volcanism in northern Kamchatka. Most models describing the tectonic evolution of the northwest Pacific do not account forExpand
Isotope evidence for the origin of Andean granites
The genesis of subduction-related magmas in the Andean region of South America and the Antarctic Peninsula is considered in relation to the Palaeozoic to Cenozoic granitoids belts which are thoughtExpand
Rb-Sr geochronology of Graham Land, Antarctica
Thirty-five new Rb-Sr whole-rock and mineral isochrons are reported for igneous rocks from Graham Land. Magmatism was essentially continuous but peaks of activity occurred in early Jurassic, earlyExpand
The 50 Ma granodiorite of the eastern Gulf of Alaska: Melting in an accretionary prism in the forearc
The generation of granitic rocks by melting of flyschoid sediments in an accretionary prism is addressed in this study of 50 Ma silicic igneous rocks in the Gulf of Alaska, near Cordova, Alaska.Expand