06 eric monteregian

Origin of the Monteregian Hills: 

Origin of the Monteregian Hills

Introduction: 

Introduction http://www.ggl.ulaval.ca/

General Patterns of Plutons: 

General Patterns of Plutons Plutons size increase eastward Silica content increases eastward K2O/Na2O increase westward Distance to basement increases eastward Intruded between 127 and 123 ma E-W and NW-SE (Feininger, 1995)

Geological Description: 

Geological Description Inward dipping country rock Hornfels Breccia http://csmres.jmu.edu/geollab http://www.unites.uqam.ca/terre/monteregiennes http://www.unites.uqam.ca/terre/monteregiennes

Plume Hypothesis: 

Plume Hypothesis http://oceanexplorer.noaa.gov/explorations

Opening of Oceans: 

Opening of Oceans (Faure, 1996)

Beauharnois Axis: 

Beauharnois Axis Kumarapeli,1970

Beauharnois Axis (cont.): 

Beauharnois Axis (cont.) (Kumarapeli,1970)

Ottawa-Bonnechère Graben: 

Ottawa-Bonnechère Graben (Faure, 1996)

Ottawa-Bonnechère Graben: 

Ottawa-Bonnechère Graben (Philpotts, 1970)

Mode of Emplacement: 

Mode of Emplacement (Seguin, 1982)

Mode of Emplacement: 

Mode of Emplacement (Feininger, 1995)

Dikes: 

Dikes Similar chemical trend as plutons ENE-WSW and ESE-WNW Lamprophyres Emplaced before major magmatism? 3 distinct period of injections 139-129ma 121-117ma 110-107ma

Conclusion: 

Conclusion 2 main hypothesis Plume Along fractures Via Beaharnois Axis Via Ottawa-Bonnechère graben 2 emplacement hypothesis Via shallow dipping planes Via small lacollith fed by dikes and sills

Bibliography: 

Bibliography Adams, F.D.A., 1903. The Monteregian Hills- A Canadian Petrographic province. J. Geol., 11:239-282. Bédard, J.H., 1985. The opening of the atlantic, the Mesozoic New England igneous province, and mechanisms of continental breakup. Tectonophysics, 113: 209-232. Faure, S., Tremblay, A. and Angelier J., 1996. State of intraplate stress and tectonism of northeastern America since Cretaceous times, with particular emphasis on the New England-Quebec igneous province. Tectonophysics, 255: 111-134. Feininger, T. and Goodacre A.K., 1995. The eight classical Monteregian hills at depth and the mechanism of their intrusion. Can. J. Earth Sci., 32: 1350-1364. Hodgson, C.J., 1968. Monteregian dike rocks. Unpubl. Ph.D. Thesis, McGil University, Montréal, 168 pp. Kumarapeli P.S., 1970. Monteregian alkalic magmatism and the St. Lawrence rift system in space and time. In: G. Perrault (Editor), Alkaline Rocks: the Monteregian Hills. Mineral Assoc. Can., pp.421-431. Philpotts A.R., 1970. Mechanism of emplacement of the Monteregian intrusions. Canadian Mineralogist, 10:395-410. Seguin, M.K., 1982. Emplacement of the Monteregian Hills of Québec; geophysical evidence. Tectonophysics, 86: 305-317. Sleep N.H., 1990. Monteregian Hotspot Track : A Long-Lived Mantle Plume. J. of Geophysical Research, Vol., 95, No. B13, pp. 21 983-21 990.