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Full-Text Articles in Social and Behavioral Sciences
Eoarchaean Crustal Growth In West Greenland (Itsaq Gneiss Complex) And In Northeastern China (Anshan Area): Review And Synthesis, Allen P. Nutman, Vickie C. Bennett, Clark R L Friend, Frances Jenner, Yusheng Wan, Dunyi Liu
Eoarchaean Crustal Growth In West Greenland (Itsaq Gneiss Complex) And In Northeastern China (Anshan Area): Review And Synthesis, Allen P. Nutman, Vickie C. Bennett, Clark R L Friend, Frances Jenner, Yusheng Wan, Dunyi Liu
Faculty of Science - Papers (Archive)
Eoarchaean crust in West Greenland (the Itsaq Gneiss Complex, 3870-3600 Ma) is >80% by volume orthogneisses derived from plutonic tonalite-trondhjemite-granodiorite (TTG) suites,3850, c. 3810 and c. 3710 Mahave some compositional similarities to modern island arc basalts (IAB), suggesting their origin by hydrous fluxing of a suprasubduction-zone upper mantle wedge. Most of the Eoarchaean tonalites match in composition high-silica, low-magnesian adakites, whose petrogenesis is dominated by partial melting of garnetiferous mafic rocks at high pressure. However, associated with the tonalites are volumetrically minor more magnesian quartz diorites, whose genesis probably involved melting of depleted mantle to which some slab-derived component had …
Detrital Zircon Sedimentary Provenance Ages For The Eoarchaean Isua Supracrustal Belt Southern West Greenland: Juxtaposition Of An Imbricated Ca. 3700 Ma Juvenile Arc Against An Older Complex With 3920-3760 Ma Components, Allen P. Nutman, Clark R L Friend, Shane Paxton
Detrital Zircon Sedimentary Provenance Ages For The Eoarchaean Isua Supracrustal Belt Southern West Greenland: Juxtaposition Of An Imbricated Ca. 3700 Ma Juvenile Arc Against An Older Complex With 3920-3760 Ma Components, Allen P. Nutman, Clark R L Friend, Shane Paxton
Faculty of Science - Papers (Archive)
The amphibolite facies Eoarchaean Isua supracrustal belt (northern part of the Nuuk region, southern West Greenland) is dominated by strongly deformed metabasalts, with chert, banded iron formation, felsic volcanic and volcano-sedimentary rocks and minor gabbro and sedimentary carbonates. It comprises a suture zone between a northern terrane formed at ca. 3700 Ma and a southern one formed at ca. 3800 Ma. At the junction between these two terranes is a strongly tectonised, thin unit of metachert, BIF and carbonate-bearing rocks with minor detrital components, named the dividing sedimentary unit. Away from the belt, the northern terrane is dominated by ca. …
The Whole Rock Sm-Nd 'Age' For The 2825 Ma Ikkattoq Gneisses (Greenland) Is 800 Ma Too Young: Insights Into Archaean Ttg Petrogenesis, Clark R L Friend, Allen Phillip Nutman, Halfdan Baadsgaard, M John M Duke
The Whole Rock Sm-Nd 'Age' For The 2825 Ma Ikkattoq Gneisses (Greenland) Is 800 Ma Too Young: Insights Into Archaean Ttg Petrogenesis, Clark R L Friend, Allen Phillip Nutman, Halfdan Baadsgaard, M John M Duke
Faculty of Science - Papers (Archive)
The Ikkattoq gneisses of the Archaean gneiss complex in the Nuuk region, southern West Greenland, are the orthogneiss component within the amphibolite facies Tre Brodre terrane. They have mostly granodioritic compositions, with a small amount of quartz diorite. Sm-Nd isotopic data for a quartz diorite and five granodiorite Ikkattoq gneiss samples from within 5 km of the Ikkattoq (fjord) type locality yielded a regression with a slope equivalent to 2005 +/- 52 Ma (MSWD = 0.72). Regardless of the low MSWD, this cannot be the true age of the Ikkattoq gneisses, because all Ikkattoq gneisses yield U-Pb zircon dates of …
In Situ U-Pb, O And Hf Isotopic Compositions Of Zircon And Olivine From Eoarchaean Rocks, West Greenland: New Insights To Making Old Crust, Joe Hiess, Vickie C. Bennett, Allen P. Nutman, Ian S. Williams
In Situ U-Pb, O And Hf Isotopic Compositions Of Zircon And Olivine From Eoarchaean Rocks, West Greenland: New Insights To Making Old Crust, Joe Hiess, Vickie C. Bennett, Allen P. Nutman, Ian S. Williams
Faculty of Science - Papers (Archive)
The sources and petrogenetic processes that generated some of the Earth's oldest continental crust have been more tightly constrained via an integrated, in situ (U-Pb, O and Hf) isotopic approach. The minerals analysed were representative zircon from four Eoarchaean TTG tonalites and two felsic volcanic rocks, and olivine from one harzburgite/dunite of the Itsaq Gneiss Complex (IGC), southern West Greenland. The samples were carefully chosen from localities with least migmatisation, metasomatism and strain. Zircon was thoroughly characterized prior to analysis using cathodoluminescence, scanning electron, reflected and transmitted light imaging. The zircon from all but one sample showed only minor post-magmatic …