| 加拿大LITHOPROBE计划与Superior Province地质演化 |
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| 关键词:LITHOPROBE Superior Province Archean craton accretion |
| 基金项目:国家专项“深部探测技术与实验研究”(编号: SinoProbe-08-01) |
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| LITHOPROBE Program and Geological Evolution of Superior Province in Canada |
| Combining geological, geophysical and geochemical explore methods, LITHOPROBE program of Canada successfully researched the structural features and evolutionof the lithosphere of Canada. The study about the formation and evolution of Superior Province craton which is the largest Archean craton of North America is very typical. Disparate fragment of Mesocarchean to Eoarchean protocontinental crust and intervening tracts of Neoarchean oceanic crust were assembled through successive accretionary and collisional events between 2 720 and 2 680 Ma, resulting in the first-order easterly alignment of terranes. The 3.0 Ga North Cariobou terrane acted as a nucleus during collision with the Hudson Bay terrane to the north at 2 720 Ma, and the Winnipeg River terrane on the south(2 720–2 700 Ma), where synorogenic turbidites were trapped in the English River basin. Docking of the juvenile Wabigoon terrane further to the south occurred at 2 710–2 700 Ma, followed by collision of the Wawa-Abitibi terrane and syntectonic deposition of Quetico basin turbidites and Porcupine group wackes. The final event welded the Minnesota River Valley terrane to the southern Superior margin and tectonically underplated a wedge of probable oceanic crust beneath it. Polyphase deformation and metamorphism occurred at 2 730 to 2 680 Ma in the northeastern Superior Province andeast-trending belts and structures bend into northerly trends through a broad oroclinal flexure in central Quebec. In the regional LITHOPROBE transects CWS and AG, prominent crust reflectivity and mantle lithospheric features dip gently northward to central North Caribou latitudes.Several late-tectonic events recognized across the Superior Province characterized the cratonization process between 2 680 and 2 600 Ma. Deposition of “Timiskaming-type” conglomerates, alkaline magmatism, emplacement of crust-derived granites, regional metamorphism, hydrothermal fluid circulation, lode gold localization, and post-orogenic cooling express thermal relaxation and stabilization of a refractory lithosphere mantle keel. The progressive accretion of protocontinental and oceanic domains on a 2 000 km length scale, coupled with three-dimensional evidence for terrane stacking, provide compelling evidence that plate-tectonic-like processes drove Neoarchean assembly of the Superior Province. |
| HUANG Shi-qi,DONG Shu-wen,CHEN Xuan-hua,SHI Wei.2016.LITHOPROBE Program and Geological Evolution of Superior Province in Canada[J].Acta Geoscientica Sinica,37(s1):21-36. |
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