Abstract
| Original language | English |
|---|---|
| Pages (from-to) | 853-864 |
| Journal | Australian Journal of Earth Sciences |
| Volume | 50 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2003 |
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Revised geochronology of magmatism in the western Capricorn Orogen at 1805-1785 Ma: diachroneity of the Pilbara-Yilgarn collision. / Evans, D.A.D.; Sircombe, Keith; Wingate, Michael; Doyle, M.; Mccarthy, M.; Pidgeon, R.T.; Van Niekerk, H.S.
In: Australian Journal of Earth Sciences, Vol. 50, No. 6, 2003, p. 853-864.Research output: Contribution to journal › Article
TY - JOUR
T1 - Revised geochronology of magmatism in the western Capricorn Orogen at 1805-1785 Ma: diachroneity of the Pilbara-Yilgarn collision
AU - Evans, D.A.D.
AU - Sircombe, Keith
AU - Wingate, Michael
AU - Doyle, M.
AU - Mccarthy, M.
AU - Pidgeon, R.T.
AU - Van Niekerk, H.S.
PY - 2003
Y1 - 2003
N2 - The June Hill Volconics occupy a central stratigraphic position in the tectonic evolution of the Capricorn Orogeny that occurred along the southwestern margin of the Pilbara Craton in Palaeoproterozoic time. The volcanic rocks have been interpreted alternatively as due to continental rifting, foreland-basin development, or backarc extension. Previous multigrain zircon U-Pb results from these rocks, as well as from an unnamed rhyolitic porphyry that is interstratified in turbidites of the overlying Ashburton Formation, are influenced by the combined effects of Pb loss and xenocrystic inheritance. We report new SHRIMP zircon ages of 1799 8 and 1786 11 Ma, respectively from the June Hill Volcanics and the unnamed porphyry, both of which have been deformed during the Capricorn Orogeny. Close similarity between these ages and results from various late-stage Capricorn granitoids (including our new SHRIMP result of 1795 8 Ma for the Minnie Creek granite) imply rapid development of the western Ashburton Trough, accumulating and deforming similar to 10 km of turbiditic sediments in about 10 million years, Comparison of our new June Hill age with previous SHRIMP results from the central Ashburton Trough implies that foreland-basin development of the Capricorn Orogeny was significantly diachronous,younging westward during oblique Pilbara-Yilgarn convergence.
AB - The June Hill Volconics occupy a central stratigraphic position in the tectonic evolution of the Capricorn Orogeny that occurred along the southwestern margin of the Pilbara Craton in Palaeoproterozoic time. The volcanic rocks have been interpreted alternatively as due to continental rifting, foreland-basin development, or backarc extension. Previous multigrain zircon U-Pb results from these rocks, as well as from an unnamed rhyolitic porphyry that is interstratified in turbidites of the overlying Ashburton Formation, are influenced by the combined effects of Pb loss and xenocrystic inheritance. We report new SHRIMP zircon ages of 1799 8 and 1786 11 Ma, respectively from the June Hill Volcanics and the unnamed porphyry, both of which have been deformed during the Capricorn Orogeny. Close similarity between these ages and results from various late-stage Capricorn granitoids (including our new SHRIMP result of 1795 8 Ma for the Minnie Creek granite) imply rapid development of the western Ashburton Trough, accumulating and deforming similar to 10 km of turbiditic sediments in about 10 million years, Comparison of our new June Hill age with previous SHRIMP results from the central Ashburton Trough implies that foreland-basin development of the Capricorn Orogeny was significantly diachronous,younging westward during oblique Pilbara-Yilgarn convergence.
U2 - 10.1111/j.1400-0952.2003.01031.x
DO - 10.1111/j.1400-0952.2003.01031.x
M3 - Article
VL - 50
SP - 853
EP - 864
JO - Australian Journal of Earth Sciences
JF - Australian Journal of Earth Sciences
SN - 0812-0099
IS - 6
ER -