27.10.2014 Views

title of the thesis - Department of Geology - Queen's University

title of the thesis - Department of Geology - Queen's University

title of the thesis - Department of Geology - Queen's University

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

The 1290 Shear Zone and <strong>the</strong> 118 System shear zones were fit to a Riedel model in previous work<br />

based on ductile shear-sense indicators observed in <strong>the</strong> Creighton Deep (Siddorn, 2006; Fig. 2.16).<br />

Figure 2.16: Riedel Model <strong>of</strong> 1290 and 118-System shear zones, modified from Siddorn (2006).<br />

In this model, shortening along shear zones <strong>of</strong> <strong>the</strong> 118 Shear System and lateral motion along <strong>the</strong><br />

1290 Shear Zone are accounted for by NW-SE directed compression. This is compatible with <strong>the</strong><br />

maximum principal stress direction and regional fault style during <strong>the</strong> Penokean Orogeny and<br />

during <strong>the</strong> formation <strong>of</strong> <strong>the</strong> South Range Shear Zone (Fig. 2.17).<br />

Figure 2.17: NW-SE Penokean compression, possibly responsible for forming 1290 and 118 System<br />

shear zones, as shown in <strong>the</strong> top left Riedel model.<br />

Oblique-reverse motion along <strong>the</strong> Footwall Shear does not fit <strong>the</strong> Riedel configuration, suggesting<br />

multiple periods <strong>of</strong> fault activity. The apparent <strong>of</strong>fset 1290 Shear Zone by <strong>the</strong> Footwall Shear<br />

Zone fur<strong>the</strong>r supports this. Late-stage lateral-sense motion along steeply-dipping faults is<br />

compatible with a maximum principal stress direction oriented NNW-SSE (Cochrane, 1991).<br />

38

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!