Archean of Greenland and Fennoscandia  

作　　者：Pentti Hoelttae Victor Balagansky Adam A. Garde Satu Mertanen Petri Peltonen Alexander Slabunov Peter Sorjonen-Ward Martin Whitehouse 

机构地区：[1]Geological Survey of Finland, P.O. Box 96, FI-02151 Espoo, Finland. [2]Geological Institute, Kola Science Centre, RAS, Apatity, 184209, Russia. [3]Geological Survey of Denmark and Greenland, Фster Voldgade 10, DK-1350 Copenhagen K, Denmark. [4]Institute of Geology, Karelian Research Centre, RAS, Petrozavodsk, 185910, Russia. [5]Geological Survey of Finland, P.O. Box 1237, FI-70211 Kuopio, Finland. [6]Laboratory for Isotope Geology, Swedish Museum of Natural History, Box 50 007, SE-104 05 Stockholm, Sweden.

出　　处：《Episodes》2008年第1期13-19,共7页地质幕（英文版）

摘　　要：The North Atlantic craton in southern West Greenland mainly consists of a tectonic collage of Mesoarchean continental crustal terranes, which were amalgamated at c. 2.7 Ga and are currently exposed at mid-crustal amphibolite to granulite facies levels. Tonalitic orthogneisses predominate, intercalated with slightly older tholeiitic to andesitic metavolcanic rocks and associated gabbro-anorthosite intrusive complexes. The North Atlantic craton also contains enclaves of Eoarchean, c. 3.86-3.6 Ga orthogneisses and supracrustal rocks including the Isua greenstone （or supracrustal） belt. This is the oldest known assemblage of rocks deposited at the surface of the Earth, comprising mafic pillow lavas, banded iron formations and metasedimentary schists with local disseminated graphite of possible biogenic origin. Eoarchean rocks have not been found in Kola and Karelia in Fennoscandia where most rocks are 2.9-2.7 Ga tonalitic-trondhjemitic-granodioritic orthogneisses with intercalated coeval greenstone belts and amphibolites. Mesoarchean 3.0-3.2 Ga rocks are found in the eastern and western parts of the Karelian province. Subduction-related rocks like the Iringora supra-subduction type ophiolite and basalt-andesite-dacite-rhyolite series volcanic rocks in many greenstone belts, as well as eclogites are found in the Archean of Fennoscandia. A clear distinction between Greenland and Fennoscandia is the abundance of 2.75-2.65 Ga igneous rocks in Fennoscandia which indicates that these two cratons had a separate evolution during the Neoarchean.

关 键 词：太古代 地球科学 格陵兰岛 芬诺斯坎底亚 

分 类 号：P534.2[天文地球—古生物学与地层学]