William Peck: Geology of the Morin Anorthosite and the Morin terrane

William Peck

Professor of Geology
Geology, 422 Ho Science Center
p 315-228-6798
Geologic map of the Morin Complex
Late igneous(?) zircon growing at the grain boundary of exolved hemoilmenite and plagioclase

William Peck's Research: Geology of the Morin Anorthosite and the Morin Terrane

The Morin Anorthosite complex is 2,500 sq km batholith complex emplaced into the crust of Quebec 1.15 Billion years ago. The anorthosite complex crops out in the Laurentian Mountains northwest of Montreal, and is the ‘geologic twin’ of the Marcy anorthosite in the Adirondack Mountains of New York.  The Morin anorthosite and surrounding Morin terrane is an ideal natural laboratory for exploring the temperature, pressure, and fluid conditions in the mid-crust.

A part of my research with Colgate students in the Morin terrane focuses on the metamorphic petrology of the anorthosite and its country rocks (Etienne Morin '02, Mike Meredith '03, and Kevin Lough ‘16). Some of this work was published in the 2005 Grenville volume of the Canadian Journal of Earth Sciences. During the early parts of this study we discovered interesting zircon crystals in Fe-Ti oxide ore deposits of the Morin Complex (research by Jill Thompson '03), which we initially thought was caused by Zr exsolved from hemoilmenite during metamorphism. U-Pb dating and association with magmatic sulfides suggests that this zircon is instead late-magmatic (collaborative research with Scott Samson, Univ. Syracuse). Gary Eppich ('06) did a stable isotope study of historic magnesite ore deposits in the southern Morin terrane, and confirmed their evaporative sedimentary protolith.  Recently, Matt Quinan (’17) and I have undertaken a project to date detrital zircon and metamorphic minerals in the Morin terane, to compare to the geologic history known in the Adirondacks.

Student Presentations at Professional Meetings

Related References

Peck, WH, and Quinan, MP, 2016, Links between the Adirondacks and the Morin terrane: New evidence from geochronology: Geological Society of America Abstracts with Programs, v. 48(2), doi: 10.1130/abs/2016NE-272318.

Brown, LL, McEnroe, SA, Peck, WH, Peterson, LP, 2011, Anorthosites as Sources of Magnetic Anomalies, in Earth’s Magnetic Interior (E Petrovský, D Ivers, T Harinarayana, and E Herrero-Bervera, Eds.), Springer-Verlag, p. 321-342.

Peck, WH, 2012, Reconnaissance geochronology and geochemistry of the Mont-Tremblant gneiss of the Morin terrane, Grenville Province, Quebec: Geosphere, v. 8, p. 1356-1365.
Eppich, GR, and Peck, WH, 2006, Stable isotope geochemistry of the Kilmar magnesite deposits, Grenville Province, Quebec, Geological Society of America Abstracts with Programs, v.38, n. 2, p. 26.

Peck, WH, DeAngelis, MT, Meredith, MT, Morin, E, 2005, Polymetamorphism of marbles in the Morin terrane (Grenville Province, Quebec): Canadian Journal of Earth Sciences, v. 42, p. 1949-1965.

Thompson, J, and Peck, WH, 2003 Metamorphic zircon in Fe-Ti ores, Morin Anorthosite Complex (Grenville Province, Quebec), Geological Society of America Abstracts with Programs, v.35, n. 3., p. 95.

Peck, WH, and Valley, JW, 2000, Large crustal input to high δ 18O anorthosite massifs of the southern Grenville Province: New evidence from the Morin Complex, Quebec: Contributions to Mineralogy and Petrology v.139, p. 402-417.