Nipissing sills

Nipissing sills associated with Ungava magmatic event

The Nipissing sills, also called the Nipissing diabase, is a large 2217– to 2210–million year old group of sills in the Superior craton of the Canadian Shield in Ontario, Canada,^[1] which intrude the Huronian Supergroup.^[2] Nipissing sills intrude all the Huronian sediments and older basement rocks in the northern margin of the Sudbury Basin;^[3]:25,67 they were emplaced after the faulting and folding of Huronian rocks, and are hornblende gabbro of tholeiitic basalt composition.^[3]:25 In the Sudbury–Elliot Lake area the Nipissing diabase is deformed; outcrops are parallel to the fold axes of the Huronian sedimentary rocks.^[2] Nipissing diabase intrusions are east-northeast trending and are no wider than 460 m (1,510 ft).^[4]:972

The Nipissing sills in the Southern Province of the Superior craton are thought to originate from a radiating dike swarm area 1,300 km (810 mi) to the northeast.^[5]:3 The mantle source for the Nipissing sills did not come from the mantle beneath the Southern Province that had generated the 2500– to 2450–million year old Matachewan dike swarm.^[5]:3 The 2217– to 2210–million year old Ungava magmatic event – located under the Labrador Trough – fed the Nipissing sills;^[5]:3,5 evidence shows the sills were laterally fed from a mantle plume center 1,500 km (930 mi) away via the 2216–million year old Senneterre dikes which form part of the radiating dike swarm.^[6]

See also

Volcanism of Canada portal

• Volcanism of Eastern Canada

References

1. ^ Ancient LIPS Reconstructed (2.50, 2.45, 2.22 & 2.10 Ga): The Utility Of Precise Magmatic “Barcodes” And “Piercing Points” In Matching Ancient Continental Fragments
2. ^ ^{a b} Palmer, H. C.; Ernst, R. E.; Buchan, K. L. (April 1, 2007). "Magnetic Fabric Studies of the Nipissing sill province and Senneterre dykes, Canadian shield, and Implications for Emplacement". Canadian Journal of Earth Sciences (NRC Research Press) 44 (4): 507–528. doi:10.1139/E06-096. http://www.ingentaconnect.com/content/nrc/cjes/2007/00000044/00000004/art00006. Retrieved June 12, 2010. 
3. ^ ^{a b} Siddom, James P. (1999). Differential Uplift of the Archean Basement North of the Sudbury Basin: Petrographic Evidence from tahe Matachewan Dyke Swarm (Thesis). http://google.com/scholar?q=cache:zlfnuPgaVsAJ:scholar.google.com/+Nipissing+sills&ht=en&as_sdt=2000. Retrieved June 12, 2010. 
4. ^ Parmenter, Andrew C.; Lee, Christopher B.; Coniglio, Mario (2002). ""Sudbury Breccia" at Whitefish Falls, Ontario: Evidence for an Impact Origin". Canadian Journal of Earth Sciences 39 (6): 971–982. doi:10.1139/E02-006. http://article.pubs.nrc-cnrc.gc.ca/ppv/RPViewDoc?issn=1480-3313&volume=39&issue=6&startPage=971. Retrieved June 12, 2010. 
5. ^ ^{a b c} Ernst, Richard E.. Large Igneous Provinces in Canada Through Time and Their Metallognic Potential (Report). http://gsc.nrcan.gc.ca/mindep/synth_prov/lip/pdf/ernst_lips.pdf. Retrieved June 12, 2010. 
6. ^ Palmer, H.C.; Ernst, R.E.; Buchan, K.L.. Mapping Flow Patterns in Nipissing sills of the Southern Province, Canadian shield: a Magnetic Fabric Study. American Geophysical Union, Spring Meeting 2004, abstract #GP34A-04. Bibcode 2004AGUSMGP34A..04P.