Brand new Geochemical Data Toolkit (GCDkit 3.0) – is it worth upgrading and browsing documentation? (Yes!)

The freeware Geochemical Data Toolkit (www.gcdkit.org) is a flexible R-language package designed for handling, recalculation and plotting of whole-rock geochemical data from igneous and metamorphic rocks. The current version, GCDkit 3.0, was released in September 2011 and developed in the brand new R 2.13.0 for Windows. The release addresses some stability issues and improves the appearance of the plots. Apart from several new diagrams and plugins, it brings principal conceptual changes. The first is the internationalization – it introduces dictionaries, serving for the translation of classification diagrams. Czech and French localizations are provided as an example. Moreover, the system enables editing plates of multiple plots, in a manner previously available only for some of the stand-alone plots. Lastly, most of the commands can be invoked in batch mode, thus further speeding up otherwise tedious processing of large data files.Meskimen’s Law: There’s never time to do it right, but there’s always time to do it over

Arc-like magmatism in syn- to post-collisional setting: The Ediacaran Angra Fria Magmatic Complex (NW Namibia) and its cross-Atlantic correlatives in the south Brazilian Florianópolis Batholith

Ediacaran syn-tectonic plutonic rocks (amphibole gabbros, quartz diorites/tonalites to biotite- and muscovite-bearing granites) of the Angra Fria Magmatic Complex (Kaoko Belt, north-western Namibia) belong to two compositionally similar, magnesian, transitional tholeiitic–calc-alkaline suites, the Older (∼625–620 Ma) and the Younger (∼585–575 Ma). Both have counterparts in the broadly contemporaneous Florianópolis Batholith (southern Brazil), from which they were separated during the Cretaceous opening of the southern Atlantic. In the Angra Fria Magmatic Complex, the only unequivocal mantle contributions are identified in mingling zones of the Younger Suite and hybrid mafic–intermediate dykes of uncertain age. Previously published Hf-in-zircon isotopic data, together with new whole-rock geochemical and Sr–Nd isotopic signatures, underline an important role of crustal anatexis of a material with late Palaeoproterozoic to early Mesoproterozoic mean crustal residence (1.9–1.5 Ga). This interval resembles some of the published Nd model ages for Tonian ‘Adamastor Rift’-related felsic magmatic rocks in the Namibian Coastal and Uruguayan Punta del Este terranes. In detail, the Older Suite probably originated mainly by fluid-present melting of metabasalts and metatonalites, followed by (near) closed-system fractional crystallization (with or without accumulation) of amphibole ± plagioclase. For the Younger Suite, the principal process was the dehydration melting of relatively felsic lower crustal protoliths (metagreywackes or intermediate–acid orthogneisses >> metapelites), leaving garnet in the residue. Based on the geological context, the conspicuous enrichment of hydrous-fluid-mobile large ion lithophile over the conservative high field strength elements is not interpreted through a classic model of oceanic plate subduction, devolatilization, and fluxed-melting of the overriding mantle wedge. Instead, it is thought to reflect high-grade metamorphism of deeply buried continental crust and attendant water-fluxed melting of the overlying crustal lithologies, connected with inversion of the Tonian ‘Adamastor Rift’

Geology of the Metapán volcanic field NW El Salvador

Metapán volcanic field occupies the eastern margin of the Ipala Graben and represents one of several 'Behind volcanic front' type fields in El Salvador. It was subdivided into four zones in regard to the distinct age and location of each of them. The duration of the volcanic activity in the Metapán area has been from Pliocene to Quaternary. The volcanism started with the formation of the El Cóbano shield-volcano in the SE part of the study area, which is preserved as a relict of a sequence of basaltic lavas, approximately 300 m thick. Later volcanic activity represented by Strombolian cones, Hawaiian fissure vents and lava fields took place in three separated areas: El Shiste to the northwest, Ostúa to the west and San Diego to the south of the Metapán town. All studied volcanic events in this area are older than the last Plinian eruption of Ilopango caldera, which produced tephra of Tierra Blanca Joven (TBJ: 430 AD)

Cambrian–Ordovician magmatism of the Ikh-Mongol Arc System exemplified by the Khantaishir Magmatic Complex (Lake Zone, south–central Mongolia)

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