Page 385 - Global Tectonics

PRECAMBRIAN TECTONICS AND THE SUPERCONTINENT CYCLE 367

Anton terrane Yellowknife Basin
(a) 1104 1103 1102 1101
5.4
5.4
5.4 5.6 5.6
5.4
0 6 6 6.2 5.4 5.6 5.4 8.4

6.2
6.2
8.0
Depth (km) 10 6.4 6.8 6.6 7.6
6.4
6.4
20
7.2
6.8
6.8
6.6
6.6
6.8
30
8.2
8.2
6.0
40 8 8 8 8.2 6.4
NW Segment A SE 5.6
50 2.0
0 20 40 60 80 100 120 140
Distance (km)
Hottah Great Bear Contwoyto
(b) 1108 1107 1105 1104
0
6 6 6.2
6 6
Depth (km) 10 6.4 6.8 6.6 6.8
6.2
6.2
6.2
6.4
6.4
6.4
20
6.6
6.6
6.6
6.8
6.8
30
8.2
40 8.2 8 8
SW Segment B NE
50
0 20 40 60 80 100 120 140 160 180 200 220
Distance (km)
(c) 1111 Fort Simpson 1110 1109 Hottah 1108
0 5.4 5.6 6 6 5.6 5.8
5.4
5.6
5.6
5.8
Depth (km) 10 6.2 6.8 7 7 6.4 6.6 6 6 6.8
6.2
6.2
6.2
20
6.4 6.6
6.8
6.8
30
7.4
7.8
7.6
40 8 8 7.8 7.6 7.4
W Segment C E
50
0 20 40 60 80 100 120 140 160 180 200
Distance (km)
Nahanni Fort Simpson
(d) 1112 1111 1110
0
5.8
5.8 6 6 8.4
8.0
Depth (km) 10 6.2 6.6 7 7 6.8 7.6
6.2
7.2
20
6.4
6.4
6.8
6.6
6.8
30
6.0
40 8 8 6.4
SW Segment D NE 5.6
50 2.0
0 20 40 60 80 100 120
Distance (km)
Fig. 11.16 P-wave velocity model for (a) Slave province, (b) eastern part of the Wopmay Orogen and transition to
Slave Province, (c) Hottah and Fort Simpson terranes, and (d) Fort Simpson terrane and Nahanni domain (after
Fernández-Viejo & Clowes, 2003, with permission from Blackwell Publishing). Line segments shown in Fig. 11.15a.
−1
Contours are drawn at 0.2 km s increments. Heavy black lines are locations from which wide-angle refl ections were
observed.
of supercontinent assembly by plate tectonic processes 10.4.2), represents an important marker of the onset of
(Fig. 11.12) (Section 11.5.4). tectonic processes similar to those seen in the Phanero-
The appearance of the metamorphic products of zoic Earth (O’Brien & Rötzler, 2003; Collins et al., 2004;
subduction and continental collision during the Early Brown, 2006). Phanerozoic eclogites commonly pre-
Proterozoic, including eclogites and other >1 GPa high- serve evidence of having been partially subducted to
pressure metamorphic assemblages (e.g. Sections 9.9, depths greater than ∼50 km and then rapidly exhumed