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The age of undeformed dacite intrusions within the Kolaka Fault zone, SE Sulawesi, Indonesia

Journal Article


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Abstract


  • We present petrologic, geochemical and U-Pb sensitive high resolution ion microprobe (SHRIMP) data from previously undocumented dacite intrusions from the SE Arm of Sulawesi. The dacites occur in a strand of a major fault (the Kolaka Fault) that crosses the SE Arm of Sulawesi and northern Bone Bay. U-Pb SHRIMP dating shows the "Kolaka Dacite" yields zircon grains and overgrowths that range between ca. 4 and 7. Ma, indicating active magmatism in SE Sulawesi at this time. The youngest age population (4.4. ±. 0.2. Ma) from this range is interpreted to be the maximum crystallization age for the dacite. The Kolaka Dacite is undeformed, and so potentially intruded during or after movement within a strand of the Kolaka Fault. The dacites may have otherwise been emplaced passively along existing foliation planes in the country rock schist. Additional U-Pb data were collected from inherited zircons, yielding ages between 8. Ma and 1854. Ma. We consider that these inherited zircons are xenocrysts, derived from either (1) a partially melted protolith and/or (2) xenocrysts assimilated during ascent of the magma. In either case, the inherited zircons record the age of the basement rocks beneath this part of SE Sulawesi. These inherited zircon cores show that the SE arm of Sulawesi is underlain by Proterozoic or younger material, validating earlier ideas that the crust here was derived from Gondwana.

UOW Authors


  •   Lloyd White
  •   Hall, Robert (external author)
  •   Armstrong, Richard A. (external author)

Publication Date


  • 2014

Citation


  • White, L. T., Hall, R. & Armstrong, R. A. (2014). The age of undeformed dacite intrusions within the Kolaka Fault zone, SE Sulawesi, Indonesia. Journal of Asian Earth Sciences, 94 105-112.

Scopus Eid


  • 2-s2.0-84907164100

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=5406&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/4382

Number Of Pages


  • 7

Start Page


  • 105

End Page


  • 112

Volume


  • 94

Abstract


  • We present petrologic, geochemical and U-Pb sensitive high resolution ion microprobe (SHRIMP) data from previously undocumented dacite intrusions from the SE Arm of Sulawesi. The dacites occur in a strand of a major fault (the Kolaka Fault) that crosses the SE Arm of Sulawesi and northern Bone Bay. U-Pb SHRIMP dating shows the "Kolaka Dacite" yields zircon grains and overgrowths that range between ca. 4 and 7. Ma, indicating active magmatism in SE Sulawesi at this time. The youngest age population (4.4. ±. 0.2. Ma) from this range is interpreted to be the maximum crystallization age for the dacite. The Kolaka Dacite is undeformed, and so potentially intruded during or after movement within a strand of the Kolaka Fault. The dacites may have otherwise been emplaced passively along existing foliation planes in the country rock schist. Additional U-Pb data were collected from inherited zircons, yielding ages between 8. Ma and 1854. Ma. We consider that these inherited zircons are xenocrysts, derived from either (1) a partially melted protolith and/or (2) xenocrysts assimilated during ascent of the magma. In either case, the inherited zircons record the age of the basement rocks beneath this part of SE Sulawesi. These inherited zircon cores show that the SE arm of Sulawesi is underlain by Proterozoic or younger material, validating earlier ideas that the crust here was derived from Gondwana.

UOW Authors


  •   Lloyd White
  •   Hall, Robert (external author)
  •   Armstrong, Richard A. (external author)

Publication Date


  • 2014

Citation


  • White, L. T., Hall, R. & Armstrong, R. A. (2014). The age of undeformed dacite intrusions within the Kolaka Fault zone, SE Sulawesi, Indonesia. Journal of Asian Earth Sciences, 94 105-112.

Scopus Eid


  • 2-s2.0-84907164100

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=5406&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/4382

Number Of Pages


  • 7

Start Page


  • 105

End Page


  • 112

Volume


  • 94