Mechanics of the giant radiating Mackenzie dyke swarm: A paleostress field modeling

• Published in: Journal of Geophysical Research
• Main Authors: Hou, Guiting, Kusky, T. M., Wang, Chuancheng, Wang, Yanxin
• Other Authors: Hou, GT (reprint author), Peking Univ, Sch Earth & Space Sci, Key Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China., Peking Univ, Sch Earth & Space Sci, Key Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China., China Univ Geosci, Gorges Geohazards Res Ctr 3, Wuhan 430074, Peoples R China., China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074, Peoples R China.
• Format: Journal/Newspaper
• Language: English
• Published: journal of geophysical research solid earth 2010
• Subjects: INTRAPLATE STRESS-FIELD; ELASTIC THICKNESS; TECTONIC IMPLICATIONS; CANADIAN SHIELD; LABRADOR SEA; EMPLACEMENT; PROVINCE; RECONSTRUCTION; LAURENTIA; PLATE; Coppermine River; Labrador Sea
• Online Access: https://hdl.handle.net/20.500.11897/155888; https://doi.org/10.1029/2007JB005475

The 1.27 Ga Mackenzie dyke swarm of the Canadian Shield is a giant radiating dyke swarm that gradually swings in orientation from N-S in the focal area to NW-SE trends in peripheral areas. In this paper, we propose a new model (the "Plug'' model) that accounts for the paleostress contribution to the mechanism of emplacement for the Mackenzie dyke swarm in the Canadian Shield. The 1.27 Ga stress field on the Canadian Shield calculated by the "Plug'' model explains the radiating nature of the Mackenzie dyke swarm around the Coppermine River lava field by local stress concentrations. The parallel nature of the dyke swarm at distance (more than 1000 km) from the focal source can be explained by the existence of a regional tectonic stress field created by ridge push acting on the southeast margin of the Canadian Shield from the Grenville Ocean. The thin elastic plate and two-dimensional cross-section modeling suggest that the interaction between stresses from a mantle upwelling and the Grenville Ocean spreading play an important role in the intrusion mechanism of the Mackenzie dyke swarm. The change in dyke orientation from N-S trending to NW-SE trending is caused by coupling between resistance from the focal area (Plug area) and a Grenville Ocean ridge push. http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000274359300001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 Geochemistry & Geophysics SCI(E) 8 ARTICLE null 115