Page 377 - Global Tectonics

Coppin Gap
Belt
Marble Bar C
Belt
Mt Edgar
Granitoid
Complex
WGB B
A SAL Salgash Subgroup
Coongan Corunna DF Duffer Formation
Belt Downs
Granitoid Kelly TT Talga Talga Subgroup
Complex Belt Active deformation
Inactive shear

(a)
Mt Edgar Dolerite sills feed the
A Shear Zone B ? 3.45 Ga Salgash Subgroup Basalts C
0
SAL
5
DF DF DF
TT 10
TT TT km
TT 15
Weakened crust
20
Basement unknown 25
Layer parallel NE–SW extension and Emplacement of 3.46–3.43 Ga
doming of the precursor to the Mt. Edgar Dome precursor to gneisses

(b)
Back-tilting Compressed
and exhumation geothermal Sinistral transfer movement
of the MESZ gradient
Flank of detachment
Mt. Edgar Dome
WARRAWOONA
BELT
A
0 DF C
SAL
5 TT
km 10 DF
TT
TT Emplacement of 3.31 Ga
15 granitoids
(c)
Folding of
the greenstones Discordant intrusion post-extensional
CORUNNA DOWNS A WARRAWOONA BELT B MT. EDGAR GRANITOID COMPLEX C
0
DF DF
5 TT
km 10 TT ?
15
20 ? Discordant intrusion
Steepening of the
back-tilted flank and
batholith-up sense of shear

Fig. 11.11 Cartoon summarizing the tectonic and magmatic development of the Warrawoona Greenstone Belt (WGB)
and Mt. Edgar Dome by horizontal extension (after Kloppenburg et al., 2001, with permission from Elsevier). (a) Pre
3.33 Ga gabbro/diorite and dolerite intrusions, NE–SW extension, and doming of the Mt. Edgar Granitoid Complex.
(b) Differential extension on the Mt. Edgar Shear Zone (MESZ) and lateral motion along a transfer zone within the
granitoid complex at 3.31 Ga. (c) Final localized normal displacements and steepening of the MESZ followed by
discordant intrusions of post-extensional plutons.