An Australian source for Pacific-Gondwanan zircons: Implications for the assembly of northeastern Gondwana
© 2017 Geological Society of America. Detrital zircons in Neoproterozoic-Paleozoic basins of the Pacific-Gondwana (PG) region contain a distinctive 700-500 Ma population conventionally considered to be derived from Antarctica. However, the 700-600 Ma age component of the population predates major pe...
Published in: | Geology |
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Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Geological Society of America
2017
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Subjects: | |
Online Access: | https://hdl.handle.net/20.500.11937/55800 https://doi.org/10.1130/G39152.1 |
Summary: | © 2017 Geological Society of America. Detrital zircons in Neoproterozoic-Paleozoic basins of the Pacific-Gondwana (PG) region contain a distinctive 700-500 Ma population conventionally considered to be derived from Antarctica. However, the 700-600 Ma age component of the population predates major peripheral orogenesis (Terra Australis orogen), which began at ca. 580 Ma, and the highly evolved e Hf(t) -in-zircon values (to -40) require an Archean source, which is not proximal to the Terra Australis active margin. Based on similar e Hf(t) arrays defined by Neoproterozoic granites in Western Australia and detrital zircon populations from the surrounding basins, we suggest that PG zircon grains were derived from the > 2000-km-long, late Neoproterozoic Paterson-Petermann orogen, which sutured northern and southern Australia at 550-530 Ma. This Himalayan-style orogen was responsible for amalgamating Southeast Asian terranes into northeast Gondwana, thereby constraining the paleogeography of the northern Gondwanan margin at the Precambrian-Cambrian boundary. Remarkable isotopic similarity of zircon grains with the Lhasa terrane of Tibet suggests that the Paterson-Petermann orogen was the eastern sector of the developing circum-Gondwana subduction system from ca. 700 Ma. |
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