Mid Continent rift - East Shore

background

The Mid-Continent Rift is a tear in the N. American continent that was accompanied by the eruption of vast volumes of basalt rocks. Most people do not think of places such as Michigan or Ontario and consider them locales where volcanoes have erupted - but they have. A billion years ago, the rocks to the left were erupted in one of the largest magmatic events on the planet - a large igneous province. These black rocks are ubiquitous around Lake Superior.

Concept

Much of the vast mineral wealth of Michigan in terms of copper comes from events associated with this billion year volcanic event and the aftermath of it. Our project is explores the magma sequence at a place called Mamainse Point in Ontario along the eastern short of Lake Superior. Here, a stack of flows, 5km thick preserves some of the best record we have of volcanism in the Mid Continent Rift. We aim to read this record by examining the chemistry of the rocks.

discoveries

ABSTRACTS

1. *Matthews, T., and Rooney, T.O., 2009. Deducing rhyolite origins in Keweenawan magmas - Geochemical correlations with flood basalts, Mamainse Point, ON. EOS Trans. AGU. v.90 (52), V51A-1655.

2. *Hudgins, T.R., and Rooney T.O., 2009. Geochemical correlations between dikes and flows in the Keweenawan flood basalt province: Geological Society of America Abstracts with Programs.

3. Rooney, T.O., Sinha, K., and Hanan, B., 2011. Rifting and re-rifting: Geochemistry as a temporal probe. EarthScope-GeoPRISMS Opportunities in Eastern North America planning meeting, Bastrop, TX, May 20-21.

4. Rooney, T.O., Pace, A., Hudgins, T., and Matthews, T., 2011. Lithospheric modification beneath the Mid-Continent rift system: Geochemistry as a temporal probe: EARTHSCOPE National Meeting.

5. Rooney, T.O., Stein, S., and Moucha, R., 2013. Combining EarthScope data with petrology and geochemistry to explore the Mid-Continent Rift's Evolution. EarthScope National Meeting.

6. *Kelly, T., Rooney, T.O., *Svoboda, C., *Lavigne, A., Girard, G., Probing the composition of the Lithospheric Mantle during the Initiation of the Mid-Continent Rift. Presented at the Annual Meeting for the Institute for Lake Superior Geology, Wawa, Ontario, Canada. May 10-11 2017.

7. Rooney T.O., LaVigne, A.*, Konter, J., Brown, E., Stein, S., Moucha R., Stein, C., 2018, Constraining the Geochemical Reservoirs Contributing to Volcanism in the Keweenaw LIP. Abstract 16-8. Geological Society of America Abstracts with Programs v. 50 (6).

8. Hudgins, T., Rooney, T.O., Magmatic Plumbing Evolution during the Latent Phase of the Midcontient Rift, 2018, Abstract 16-9. Geological Society of America Abstracts with Programs v. 50 (6).

9. Vriese, N.*, Rooney, T.O., Girard G., 2018, Geochemical Analysis of Deep Carbon Transport at the 1.1 Ga Seabrook Lake Ontario Carbonatite Complex, Abstract 68-3. Geological Society of America Abstracts with Programs v. 50 (6).

10. Martella, K.E.K.*, LaVigne A.*, Svoboda, C.D.*, Rooney T.O., Girard, G., Brown, E., Stein, S., Stein, C., Moucha R., 2018. Implications of geochemical, petrographic and stratigraphic analyses of the upper Portage Lake Volcanics for the Keweenaw flood basalts. Abstract 119-7. Geological Society of America Abstracts with Programs v. 50 (6).

11. LaVigne A.*, Rooney T.O., Moucha R., Brown, E., Stein, S., Stein, C., 2018, Terminal stages of a dying rift. Abstract 16-11. Geological Society of America Abstracts with Programs v. 50 (6).

12. Martella, K.E.K.*, LaVigne A.*, Svoboda, C.D.*, Rooney T.O., Girard, G., Brown, E., Stein, S., Stein, C., Moucha R., 2018. Implications of geochemical, petrographic and stratigraphic analyses of the upper Portage Lake Volcanics for the Keweenaw flood basalts. Presented at the NASA Michigan Space Grant Consortium Conference in Ann Arbor, November 10^th, 2018.