TY - JOUR

T1 - Eurekan faults on northern Ellesmere Island, Arctic Canada

T2 - from Cenozoic strike-slip tectonics to recent seismicity

AU - Brandes, Christian

AU - Piepjohn, Karsten

N1 - Funding Information: The German Research Foundation (DFG) is gratefully acknowledged for funding Christian Brandes (project BR 3779/3-1). Fieldwork conducted under the CASE 19-expedition in 2017 would not have been feasible without support of the following organizations: Hamlets of Grise Fiord and Resolute Bay, Hunters and Trappers Associations of Grise Fiord and Resolute Bay, Nunavut Impact Review Board, Nunavut Planning Commission, Nunavut Research Institute, Nunavut Water Board and the Qikiqtani Inuit Association. We are grateful to the Canadian Polar Continental Shelf Program (PSCP) for the excellent logistic support. The fieldwork would not have been possible without the people who organized the expeditions and were responsible for the safety of the expedition members: special thanks go to Christoph Kasch for his logistic and technical support and to the cook, wildlife monitors, pilots and engineers. We are grateful to Thomas Plenefisch for discussion. Three anonymous reviewers are gratefully acknowledged for their constructive comments.

PY - 2021/3

Y1 - 2021/3

N2 - The Eurekan deformation is a partially contractional Cenozoic tectonic event that affected large parts of the Arctic region. In the study area on northern Ellesmere Island, major NE-SW trending strike-slip faults occur, which are related to the Eurekan deformation. The outcrop data show that left-lateral strike-slip kinematics slightly dominate, but also right-lateral kinematics were documented. Cross-cutting relationships of the individual faults give evidence for multiple fault reactivations within major strike-slip zones. The reconstructed paleostress fields show two phases. The first phase started with a N-S compression and shifted over a NNE-SSW compression into a NNW-SSE compression. The second phase was a WNW-ESE compression. The paleostress field evolution reflects the movements of Greenland. During the Eurekan phase 1, Greenland moved northward and during Eurekan phase 2 it moved to the WNW. These motions likely controlled the stress field on northern Ellesmere Island. From the paleostress field analyses and the orientation of the strike-slip faults in the study area, it can be derived that the Eurekan phase 1 deformation is characterized by left-lateral strike-slip faults, whereas most-likely during Eurekan phase 2 the majority of right-lateral strike-slip faults formed. The paleostress field analysis implies that many Eurekan faults are reactivated Ellesmerian faults. Recent seismic events indicate ongoing tectonic activity at some of the major strike-slip faults. This sheds new light on the geodynamics of northern Ellesmere Island, which was mechanically coupled to the Greenland plate, and implies that under the recent stress field, earthquakes at strike-slip faults are still possible and some of these faults were active in at least three phases over the last 350 Myr.

AB - The Eurekan deformation is a partially contractional Cenozoic tectonic event that affected large parts of the Arctic region. In the study area on northern Ellesmere Island, major NE-SW trending strike-slip faults occur, which are related to the Eurekan deformation. The outcrop data show that left-lateral strike-slip kinematics slightly dominate, but also right-lateral kinematics were documented. Cross-cutting relationships of the individual faults give evidence for multiple fault reactivations within major strike-slip zones. The reconstructed paleostress fields show two phases. The first phase started with a N-S compression and shifted over a NNE-SSW compression into a NNW-SSE compression. The second phase was a WNW-ESE compression. The paleostress field evolution reflects the movements of Greenland. During the Eurekan phase 1, Greenland moved northward and during Eurekan phase 2 it moved to the WNW. These motions likely controlled the stress field on northern Ellesmere Island. From the paleostress field analyses and the orientation of the strike-slip faults in the study area, it can be derived that the Eurekan phase 1 deformation is characterized by left-lateral strike-slip faults, whereas most-likely during Eurekan phase 2 the majority of right-lateral strike-slip faults formed. The paleostress field analysis implies that many Eurekan faults are reactivated Ellesmerian faults. Recent seismic events indicate ongoing tectonic activity at some of the major strike-slip faults. This sheds new light on the geodynamics of northern Ellesmere Island, which was mechanically coupled to the Greenland plate, and implies that under the recent stress field, earthquakes at strike-slip faults are still possible and some of these faults were active in at least three phases over the last 350 Myr.

KW - Ellesmere Island

KW - Eurekan deformation

KW - paleostress analsysis

KW - Pearya Terrane

KW - strike-slip tectonics

UR - http://www.scopus.com/inward/record.url?scp=85124818282&partnerID=8YFLogxK

U2 - 10.1016/j.jog.2021.101816

DO - 10.1016/j.jog.2021.101816

M3 - Article

VL - 144

JO - Journal of Geodynamics

JF - Journal of Geodynamics

SN - 0264-3707

M1 - 101816

ER -