U-Pb ages from the Nipigon plate and northern Lake Superior

Davis, Donald W.; Sutcliffe, R. H.

doi:10.1130/0016-7606(1985)96<1572:uaftnp>2.0.co;2

Cited by 165 publications

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“…1), respectively. (D) Reconstruction at 1100 Ma -Laurentia was constrained by the Logan dykes pole (Halls & Pesonen 1982, Davis & Sutcliffe 1985. (E) Reconstruction at 1000 Ma -Laurentia, Baltica, and Amazonia as shown in the reconstruction of Rodínia proposed by Li et al (2008).…”

Section: The Amazonian Craton In Gondwanamentioning

confidence: 99%

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Paleomagnetism of the Amazonian Craton and its role in paleocontinents

et al. 2016

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In the last decade, the participation of the Amazonian Craton on Precambrian supercontinents has been clarified thanks to a wealth of new paleomagnetic data. Paleo to Mesoproterozoic paleomagnetic data favored that the Amazonian Craton joined the Columbia supercontinent at 1780 Ma ago, in a scenario that resembled the South AMerica and BAltica (SAMBA) configuration. Then, the mismatch of paleomagnetic poles within the Craton implied that either dextral transcurrent movements occurred between Guiana and Brazil-Central Shield after 1400 Ma or internal rotation movements of the Amazonia-West African block took place between 1780 and 1400 Ma. The presently available late-Mesoproterozoic paleomagnetic data are compatible with two different scenarios for the Amazonian Craton in the Rodinia supercontinent. The first one involves an oblique collision of the Amazonian Craton with Laurentia at 1200 Ma ago, starting at the present-day Texas location, followed by transcurrent movements, until the final collision of the Amazonian Craton with Baltica at ca. 1000 Ma. The second one requires drifting of the Amazonian Craton and Baltica away from the other components of Columbia after 1260 Ma, followed by clockwise rotation and collision of these blocks with Laurentia along Grenvillian Belt at 1000 Ma. Finally, although the time Amazonian Craton collided with the Central African block is yet very disputed, the few late Neoproterozoic/Cambrian paleomagnetic poles available for the Amazonian Craton, Laurentia and other West Gondwana blocks suggest that the Clymene Ocean separating these blocks has only closed at late Ediacaran to Cambrian times, after the Amazonian Craton rifted apart from Laurentia at ca. 570 Ma.

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Section: The Amazonian Craton In Gondwanamentioning

confidence: 99%

“…For the reconstruction at 1100 Ma (Fig. 8D), only Laurentia is constrained by Logan sills pole (Halls & Pesonen 1982, Davis & Sutcliffe 1985. Finally, Fig.…”

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Paleomagnetism of the Amazonian Craton and its role in paleocontinents

et al. 2016

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“…Current constraints have estimated volcanism in the Midcontinent Rift to have initiated ca. 1109 Ma (Davis and Sutcliffe, 1985) and continued to ca. 1087 Ma (Davis and Paces, 1990).…”

Section: Introductionmentioning

confidence: 99%

The End of Midcontinent Rift Magmatism and the Paleogeography of Laurentia

Fairchild

Swanson‐Hysell

Ramezani

et al. 2016

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Paleomagnetism of the North American Midcontinent Rift provides a robust paleogeographic record of Laurentia (cratonic North America) from ca. 1110 to 1070 Ma, revealing rapid equatorward motion of the continent throughout rift magmatism. Existing age and paleomagnetic constraints on the youngest rift volcanic and sedimentary rocks have been interpreted to record a slowdown of this motion as rifting waned. We present new paleomagnetic and geochronologic data from the ca. 1090-1083 Ma "late-stage" rift volcanic rocks exposed as the Lake Shore Traps (Michigan), the Schroeder-Lutsen basalts (Minnesota), and the Michipicoten Island

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“…The most significant mineralization took place in 134 Ma (Zhu Bingquan et al, 2005) and it is 126 Ma later than the emplacement of the basalt, indicating that the deposits were formed after diagenesis of the basalt. Time difference from the end of basalt eruption to the formation of the Keweenow-type native copper deposits ranges from 37 to 59 Ma (Davis and Sutcliffe, 1985;Davis and Paces, 1990;Davis and Green, 1997;Paces and Miller, 1993;Cannon et al, 1993;Bornhorst et al, 1988).…”

Section: Some Understandings On the Ore-forming Processmentioning

confidence: 99%

Lead isotopic systematics for native copper-chalcocite mineralization in basaltic lavas of the Emeishan large igneous province, SW China: Implications for the source of copper

et al. 2009

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The Emeishan continental flood basalt, which is widespread in Yunnan, Guizhou and Sichuan provinces of Southwest China, is the volcanic product of a Permian mantle plume, and native copper-chalcocite mineralization associated with the basalt is very common in the border area of Yunnan and Guizhou provinces. The mineralization occurred in the tuff intercalation and terrestrial sedimentary rock intercalation which were formed during the main period of basalt eruption. The orebodies are controlled by the stratigraphic position and faults. Metal ore minerals in the ores are mainly native copper, chalcocite and tenorite, with small amounts of chalcopyrite, bomite, pyrite and malachite, and sometimes with large amounts of bitumen, carbon and plant debris. Several decades of ore deposits are distributed in the neighboring areas of the two provinces, while most of them are small-scale deposits or only ore occurrences. By comparing the lead isotopic composition of the ores with that of the wall-rocks, cover and basement rocks of various periods, the source of copper in this type of ore deposits was studied in this paper. The results showed that: (1) The Pb isotopic composition of the ores from ten deposits is absolutely different from that of siliceous-argillaceus rocks of the Upper Permian Xuanwei Formation, limestones of the Lower Permian Series and Carboniferous, Cambrian sandstone-shale and recta-sedimentary rock and dolomite from the upper part of the Meso-Proterozoic Kunyang Group. This indicates that ore lead was derived neither from the cover rock nor from the basement rocks; (2) Although the Neo-Proterozoic Siman dolomite and silicalite, and dolomite in the lower part of the Kunyang Group are similar in Pb isotopic composition to the ores, lead and copper contents in these rocks are very low and they have not made great contributions to copper mineralization; (3) The ores have the same Pb isotopic composition as the basalt, the latter being enriched in copper. These facts indicate that lead and copper were derived from the basalt. According to the regional geological data and the geological-geochemical characteristics of the ore deposits, it is suggested that ore-forming materials were leached out from the basalt. The thickness and buried depth of the basalt and regional tectonic dynamics can affect the formation of large-scale copper deposits. Therefore, exploration for this type of ore deposits should be conducted in the areas from western Yunnan to western Sichuan, where there are developed basalts of great thickness, with extensive tectonic movement and magmatic activity.

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U-Pb ages from the Nipigon plate and northern Lake Superior

Cited by 165 publications

References 0 publications

Paleomagnetism of the Amazonian Craton and its role in paleocontinents

Paleomagnetism of the Amazonian Craton and its role in paleocontinents

The End of Midcontinent Rift Magmatism and the Paleogeography of Laurentia

Lead isotopic systematics for native copper-chalcocite mineralization in basaltic lavas of the Emeishan large igneous province, SW China: Implications for the source of copper

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