Kinematics and Deformation History of the Cross Lake Greenstone Belt

Greenstone belts are a common feature of Archean terrains. However, the tectonic environment for Archean earth remains in hot debate: did vertical or horizontal crustal movement dominate the Archean Eon? Small-scale structural analysis is applied to a late Archean greenstone belt in the Superior Province of the Canadian Shield so as to test the 2 end member ideas. In depth structural evaluation unveils that the Cross Lake greenstone belt has gone through 3 key events of deformation. The first event of ESE-WNW convergence and crustal thickening started folding and created northeast-trending shear zones. The configuration of the northwestern Cross Lake area is basically because of this event. It was followed by the juxtaposition of the Nelson River – Pipestone Lake high-strain zone. The final event was the juxtaposition of the Eves Rapids Complex with the progression of an important northeast-trending fault, which overprints all earlier deformation. The strain geometry…


Chapter 1: General Introduction and an Outline of the Thesis
1.1 Purpose of the Study
1.2 Initiation and Process of the Project
1. 3 Outline of the Thesis
Chapter 2: Contrasting Strain Geometries and Deformation Kinematics Expected in Obliquely – Convergent Plate Boundary Regions and in Vertical Tectonic Regimes
2.1 Obliquely-Convergent Plate Boundaries: Transpression
2.2 Vertical Tectonics
CHAPTER 3: General Statement and Geological Settings of the Cross Lake Greenstone Belt
3.1 General Statement of Archean Greenstone Belt and the Superior Province
3.2 Geological Setting of the Cross Lake Greenstone Belt
3.2.1 The Pipestone Lake Group
3.2.2 The Gunpoint Group
3.2.3 The Cross Lake Group
3.2.4 Early Intrusive Rocks
3.2.5 Achean Late Intrusive Rocks
3.2.6 Proterozoic Rocks
CHAPTER 4: Structural Analysis of the Cross Lake Greenstone Belt
4.1 General Statement
4.2 Structural Analysis of Domain I
4.2.1 D1 Deformation
4.2.2 D2 Deformation
4. 3 Structural Analysis of Domain II
4.3.1 D1 Deformation
4.3.2 D2 Deformation
4.4 NE-trending Shear Zones
4.5 Structural Analysis of the NR-PSL High-Strain Zone
4.5.1 D1 Deformation
4.4.2 D2 Deformation
4.5.3 D3 Deformation
4.6 The Northern Cross Lake Thrust
Chapter 5: Kinematic Interpretation
5.1 ESE-WNW Convergence and Accompanying Crustal Thickening
5.1.1 Interpreting the Structural Data
5.1.2 The Shape of the Strain Ellipsoid Constructed from Clast Fabric
5.1.3 Tectonic Environment…

Kinematics and Deformation History of the Cross Lake Greenstone Belt Downloads

Source: University of Maryland

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