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Kinematics of long‐lasting Paleoproterozoic transpression within the Thompson Nickel Belt, Manitoba, Canada
Author(s) -
Gapais Denis,
Potrel Alain,
Machado Nuno,
Hallot Erwan
Publication year - 2005
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2004tc001700
Subject(s) - transpression , geology , sinistral and dextral , shear zone , seismology , kinematics , tectonics , shear (geology) , archean , geodynamics , strain partitioning , strike slip tectonics , plate tectonics , petrology , paleontology , physics , classical mechanics
This paper presents a reappraisal of kinematics and tectonic history of the Thompson Nickel Belt, a major Paleoproterozoic deformation zone along the western boundary of the Archean Superior Province in Manitoba. The study, based on the analysis of foliation trajectory maps and associated shear zone arrays, emphasizes that the overall strain pattern results from transpression. Strains are large, marked by strong subvertical stretch and NW‐SE subhorizontal shortening, combined with along‐strike stretch. From these, we infer distributed crustal shortening, involving steeply plunging flow rather than large horizontal displacements, although kinematic indicators show that top‐to‐the‐west motions were dominant. Along‐strike shear indicators are poorly expressed but suggest a component of bulk dextral strike‐slip. Synkinematic thermal indicators and new geochronological data indicate that transpression could have been a long‐lasting, circa 100 Ma, event in the area.