Geochemistry of plutons in central Sumatra and their correlation to Southeast Asia tectonic history

Authors

  • Ronaldo Irzon Center for Geology Survey of Indonesia http://orcid.org/0000-0001-8450-7404
  • Ildrem Syafri Padjadjaran University
  • Nana Suwarna Geological Agency, Ministry of Energy and Mineral Resources, Indonesia
  • Johanes Hutabarat Padjadjaran University
  • Purnama Sendjaja Center for Geology Survey of Indonesia
  • Verry Edi Setiawan Center for Geology Survey of Indonesia

Keywords:

Plutons, Central Sumatra, Geochemistry, Tectonics

Abstract

Previous investigations of plutons in Sumatra were focused on age dating with minimum geochemistry composition analysis. The purpose of this study is to define the geochemistry classification of the intrusions in central Sumatra on describing the emplacement mechanism associated with Southeast Asia tectonics. The rocks composed of quartz, K-feldspar, and plagioclase with amphibole, biotite, epidote, and zircon as accessory minerals. Six of seven studied plutons range from monzodiorite to granite with metaluminous-slight peraluminous, medium to very high-K calc-alkaline, magnesian, calcic to calc-alkalic affinities. The studied samples depict a wide range of total REE composition of 39-1,369ppm. Most of the rocks denote Sr, Ti, Y, Ce, and Eu anomalies on the primitive-mantle and chondrite normalized diagram. LREE are more enriched in comparison to HREE with (La/Sm)N= 1.71-18.75 and (Gd/Lu)N= 0.15-2.59. Most of the studied plutons are classified in the I-type according to the A/CNK value, negative SiO2 to P2O5 correlation with magnesian and arc-associated character. A-type nature of Sijunjung Granite is displayed on its high silica and REE content with ferroan, calc-alkalic, and within-plate affinities. The existence of A-type intrusion implies an extensional setting during long time subduction episodes, which triggered I-type magmatism since Late Permian to Neogene in Sumatra.

Author Biographies

Ronaldo Irzon, Center for Geology Survey of Indonesia

Geoscience Department

Ildrem Syafri, Padjadjaran University

Faculty of Geological Engineering

Johanes Hutabarat, Padjadjaran University

Faculty of Geological Engineering

Purnama Sendjaja, Center for Geology Survey of Indonesia

Geoscience Department

Verry Edi Setiawan, Center for Geology Survey of Indonesia

Geoscience Department

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Published

2021-07-26

How to Cite

1.
Irzon R, Syafri I, Suwarna N, Hutabarat J, Sendjaja P, Setiawan VE. Geochemistry of plutons in central Sumatra and their correlation to Southeast Asia tectonic history. GeA [Internet]. 2021Jul.26 [cited 2021Sep.21];19:1-14, I. Available from: https://revistes.ub.edu/index.php/GEOACTA/article/view/32365

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