Advanced

Origin and geodynamic setting of Late Cenozoic granitoids in Sulawesi, Indonesia

Maulana, Adi; Imai, Akira; Van Leeuwen, Theo; Watanabe, Koichiro; Yonezu, Kotaro; Nakano, Takanori; Boyce, Adrian; Page, Laurence LU and Schersten, Anders LU (2016) In Journal of Asian Earth Sciences 124. p.102-125
Abstract

Late Cenozoic granitoids are widespread in a 1600km long belt forming the Western and Northern Sulawesi tectono-magmatic provinces. They can be divided into three rock series: shoshonitic (HK), high-K felsic calc-alkaline (CAK), and normal calc-alkaline to tholeiitic (CA-TH). Representative samples collected from eleven plutons, which were subjected to petrography, major element, trace element, Sr, Nd, Pb isotope and whole-rock δ18O analyses, are all I-type and metaluminous to weakly peraluminous. The occurrence of the two K-rich series is restricted to Western Sulawesi, where they formed in an extensional, post-subduction tectonic setting with astenospheric upwelling providing thermal perturbation and adiabatic... (More)

Late Cenozoic granitoids are widespread in a 1600km long belt forming the Western and Northern Sulawesi tectono-magmatic provinces. They can be divided into three rock series: shoshonitic (HK), high-K felsic calc-alkaline (CAK), and normal calc-alkaline to tholeiitic (CA-TH). Representative samples collected from eleven plutons, which were subjected to petrography, major element, trace element, Sr, Nd, Pb isotope and whole-rock δ18O analyses, are all I-type and metaluminous to weakly peraluminous. The occurrence of the two K-rich series is restricted to Western Sulawesi, where they formed in an extensional, post-subduction tectonic setting with astenospheric upwelling providing thermal perturbation and adiabatic decompression. Two parental magma sources are proposed: enriched mantle or lower crustal equivalent for HK magmas, and Triassic igneous rocks in a Gondwana-derived fragment thrust beneath the cental and northern parts of Western Sulawesi for CAK magmas. The latter interpretation is based on striking similarities in radiogenic isotope and trace element signatures. CA-TH granitoids are found mostly in Northern Sulawesi. Partial melting of lower-middle crust amphibolites in an active subduction environment is the proposed origin of these rocks. Fractional crystallization and crustal contamination have played a significant role in magma petrogenesis, particularly in the case of the HK and CAK series. Contamination by organic carbon-bearing sedimentary rocks of the HK and CAK granitoids in the central part of Western Sulawesi is suggested by their ilmenite-series (reduced) character. The CAK granitoids further to the north and CA-TH granitoids in Northern Sulawesi are typical magnetite-series (oxidized). This may explain differences in mineralization styles in the two regions.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Geodynamic setting, Granitoid, Indonesia, Petrogenesis, Source protoliths, Sulawesi
in
Journal of Asian Earth Sciences
volume
124
pages
102 - 125
publisher
Elsevier
external identifiers
  • scopus:84966526004
  • wos:000378463600008
ISSN
1367-9120
DOI
10.1016/j.jseaes.2016.04.018
language
English
LU publication?
yes
id
f03168bb-b0eb-4efc-82df-0d64cf0384db
date added to LUP
2016-05-24 09:05:44
date last changed
2017-09-18 11:28:52
@article{f03168bb-b0eb-4efc-82df-0d64cf0384db,
  abstract     = {<p>Late Cenozoic granitoids are widespread in a 1600km long belt forming the Western and Northern Sulawesi tectono-magmatic provinces. They can be divided into three rock series: shoshonitic (HK), high-K felsic calc-alkaline (CAK), and normal calc-alkaline to tholeiitic (CA-TH). Representative samples collected from eleven plutons, which were subjected to petrography, major element, trace element, Sr, Nd, Pb isotope and whole-rock δ<sup>18</sup>O analyses, are all I-type and metaluminous to weakly peraluminous. The occurrence of the two K-rich series is restricted to Western Sulawesi, where they formed in an extensional, post-subduction tectonic setting with astenospheric upwelling providing thermal perturbation and adiabatic decompression. Two parental magma sources are proposed: enriched mantle or lower crustal equivalent for HK magmas, and Triassic igneous rocks in a Gondwana-derived fragment thrust beneath the cental and northern parts of Western Sulawesi for CAK magmas. The latter interpretation is based on striking similarities in radiogenic isotope and trace element signatures. CA-TH granitoids are found mostly in Northern Sulawesi. Partial melting of lower-middle crust amphibolites in an active subduction environment is the proposed origin of these rocks. Fractional crystallization and crustal contamination have played a significant role in magma petrogenesis, particularly in the case of the HK and CAK series. Contamination by organic carbon-bearing sedimentary rocks of the HK and CAK granitoids in the central part of Western Sulawesi is suggested by their ilmenite-series (reduced) character. The CAK granitoids further to the north and CA-TH granitoids in Northern Sulawesi are typical magnetite-series (oxidized). This may explain differences in mineralization styles in the two regions.</p>},
  author       = {Maulana, Adi and Imai, Akira and Van Leeuwen, Theo and Watanabe, Koichiro and Yonezu, Kotaro and Nakano, Takanori and Boyce, Adrian and Page, Laurence and Schersten, Anders},
  issn         = {1367-9120},
  keyword      = {Geodynamic setting,Granitoid,Indonesia,Petrogenesis,Source protoliths,Sulawesi},
  language     = {eng},
  month        = {07},
  pages        = {102--125},
  publisher    = {Elsevier},
  series       = {Journal of Asian Earth Sciences},
  title        = {Origin and geodynamic setting of Late Cenozoic granitoids in Sulawesi, Indonesia},
  url          = {http://dx.doi.org/10.1016/j.jseaes.2016.04.018},
  volume       = {124},
  year         = {2016},
}