Abstract
The late Archean Fortescue Group and Paleoproterozoic Hamersley Group are exposed in the Hardey Syncline located at the southwestern edge of the Hamersley Basin, Pilbara Craton, Western Australia. The secondary mineral assemblages and compositions of the basaltic rocks of the Fortescue and Hamersley Groups reveal the metamorphic conditions of the study area. The estimated metamorphic grade ranges from prehnite-actinolite facies (Hamersley Group), through greenschist facies (Fortescue Group), to a transition between greenschist facies and actinolite-calcic plagioclase facies (Fortescue Group), indicating a low-pressure type metamorphic facies series. The metamorphic grade increases northward, which is opposite to the general southward increase of the regional metamorphic grade. Furthermore, the change of metamorphic grade strongly correlates with stratigraphy, and the metamorphic temperature increases with stratigraphic depth. These observations suggest that the metamorphism of the study area was caused by a thermal event before the folding due to the Ophthalmian orogeny that affected most of the Hamersley Province. Considering the presence of 2.2 Ga dolerite sills in the Hardey Syncline and the low-pressure metamorphic condition, it is suggested that the metamorphism of the study area was caused by the 2.2 Ga continental rifting, which is consistent with the reported metamorphic age.
| Original language | English |
|---|---|
| Pages (from-to) | 213-221 |
| Number of pages | 9 |
| Journal | Gondwana Research |
| Volume | 18 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jul 2010 |
| Externally published | Yes |
Fingerprint
Keywords
- Continental rifting
- Hamersley Province
- Low-pressure metamorphism
- Ophthalmian orogeny
- Paleoproterozoic
- Tectonics
ASJC Scopus subject areas
- Geology
Cite this
Stratigraphy-related, low-pressure metamorphism in the Hardey Syncline, Hamersley Province, Western Australia. / Shibuya, Takazo; Aoki, Kazumasa; Komiya, Tsuyoshi; Maruyama, Shigenori.
In: Gondwana Research, Vol. 18, No. 1, 07.2010, p. 213-221.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Stratigraphy-related, low-pressure metamorphism in the Hardey Syncline, Hamersley Province, Western Australia
AU - Shibuya, Takazo
AU - Aoki, Kazumasa
AU - Komiya, Tsuyoshi
AU - Maruyama, Shigenori
PY - 2010/7
Y1 - 2010/7
N2 - The late Archean Fortescue Group and Paleoproterozoic Hamersley Group are exposed in the Hardey Syncline located at the southwestern edge of the Hamersley Basin, Pilbara Craton, Western Australia. The secondary mineral assemblages and compositions of the basaltic rocks of the Fortescue and Hamersley Groups reveal the metamorphic conditions of the study area. The estimated metamorphic grade ranges from prehnite-actinolite facies (Hamersley Group), through greenschist facies (Fortescue Group), to a transition between greenschist facies and actinolite-calcic plagioclase facies (Fortescue Group), indicating a low-pressure type metamorphic facies series. The metamorphic grade increases northward, which is opposite to the general southward increase of the regional metamorphic grade. Furthermore, the change of metamorphic grade strongly correlates with stratigraphy, and the metamorphic temperature increases with stratigraphic depth. These observations suggest that the metamorphism of the study area was caused by a thermal event before the folding due to the Ophthalmian orogeny that affected most of the Hamersley Province. Considering the presence of 2.2 Ga dolerite sills in the Hardey Syncline and the low-pressure metamorphic condition, it is suggested that the metamorphism of the study area was caused by the 2.2 Ga continental rifting, which is consistent with the reported metamorphic age.
AB - The late Archean Fortescue Group and Paleoproterozoic Hamersley Group are exposed in the Hardey Syncline located at the southwestern edge of the Hamersley Basin, Pilbara Craton, Western Australia. The secondary mineral assemblages and compositions of the basaltic rocks of the Fortescue and Hamersley Groups reveal the metamorphic conditions of the study area. The estimated metamorphic grade ranges from prehnite-actinolite facies (Hamersley Group), through greenschist facies (Fortescue Group), to a transition between greenschist facies and actinolite-calcic plagioclase facies (Fortescue Group), indicating a low-pressure type metamorphic facies series. The metamorphic grade increases northward, which is opposite to the general southward increase of the regional metamorphic grade. Furthermore, the change of metamorphic grade strongly correlates with stratigraphy, and the metamorphic temperature increases with stratigraphic depth. These observations suggest that the metamorphism of the study area was caused by a thermal event before the folding due to the Ophthalmian orogeny that affected most of the Hamersley Province. Considering the presence of 2.2 Ga dolerite sills in the Hardey Syncline and the low-pressure metamorphic condition, it is suggested that the metamorphism of the study area was caused by the 2.2 Ga continental rifting, which is consistent with the reported metamorphic age.
KW - Continental rifting
KW - Hamersley Province
KW - Low-pressure metamorphism
KW - Ophthalmian orogeny
KW - Paleoproterozoic
KW - Tectonics
UR - http://www.scopus.com/inward/record.url?scp=77952431015&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77952431015&partnerID=8YFLogxK
U2 - 10.1016/j.gr.2010.01.002
DO - 10.1016/j.gr.2010.01.002
M3 - Article
AN - SCOPUS:77952431015
VL - 18
SP - 213
EP - 221
JO - Gondwana Research
JF - Gondwana Research
SN - 1342-937X
IS - 1
ER -