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Full-Text Articles in Physical Sciences and Mathematics
The Itsaq Gneiss Complex Of Southern West Greeland And The Construction Of Eoarchaean Crust At Convergent Plate Boundaries, Allen P. Nutman, Clark R. L Friend, Kenji Horie, Hiroshi Hidaka
The Itsaq Gneiss Complex Of Southern West Greeland And The Construction Of Eoarchaean Crust At Convergent Plate Boundaries, Allen P. Nutman, Clark R. L Friend, Kenji Horie, Hiroshi Hidaka
Faculty of Science - Papers (Archive)
The ca. 3000 km2ItsaqGneissComplex of the Nuuk region, southernWestGreenland was the first body of pre-3600 Ma crust discovered. Such ancient gneisses are now also known elsewhere, but in total form only about a millionth of the modern crust. The other 99.9999% of ancient crust was destroyed by melting and erosion over billions of years. Understanding the origin of this oldest crust is hampered by metamorphism (repeatedly) in the amphibolite or granulite facies, and most of it having been strongly deformed. The ItsaqGneissComplex is dominated by polyphase grey gneisses derived from several suites of tonalites, granites and subordinate quartz-diorites and ferro-gabbros …
~3,850 Ma Tonalites In The Nuuk Region, Greenland: Geochemistry And Their Reworking Within An Eoarchaean Gneiss Complex, Allen P. Nutman, Vickie C. Bennett, Clark R. L Friend, Kenji Horie, Hiroshi Hidaka
~3,850 Ma Tonalites In The Nuuk Region, Greenland: Geochemistry And Their Reworking Within An Eoarchaean Gneiss Complex, Allen P. Nutman, Vickie C. Bennett, Clark R. L Friend, Kenji Horie, Hiroshi Hidaka
Faculty of Science - Papers (Archive)
The Eoarchaean (>3,600 Ma) Itsaq Gneiss Complex of southern West Greenland is dominated by polyphase orthogneisses with a complex Archaean tectonothermal history. Some of the orthogneisses have c. 3,850 Ma zircons, and they vary from rare single phase metatonalites to more common complexly banded migmatites. This is due to heterogeneous strain, in situ anatexis and granitic veining superimposed during younger tectonothermal events. In the single-phase tonalites with c. 3,850 Ma zircon, oscillatory-zoned prismatic zircon is all 3,850 Ma old, but shows patchy ancient loss of radiogenic Pb. SHRIMP spot analyses and laser ablation ICP-MS depth profiling show that thin …