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Andesites of Bagana volcano, Papua New Guinea: chemical stratigraphy, and a reference andesite composition

Created 17/10/2025

Updated 17/10/2025

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Chemically analysed lavas from Bagana, an active andesitic volcano on Bougainville Island, can be assigned to one of three age groups - pre-1943, 1943-53, or 1959-75. Lavas of the oldest group are chemically the most fractionated, whereas those of the 1943-53 group are the most mafic. The rocks of the youngest group, although intermediate in degree of fractionation have K2O, Rb, and Ba abundances similar to, or lower than, the rocks of the 1943-53 group. The three groups appear to represent distinct batches of magma that were successively erupted from Bagana, possibly from a high-level reservoir that was periodically emptied and refilled. The andesites are regarded as fractionates of mantle-derived mafic magmas. Most of the crystal fractionation probably took place during ascent from the mantle source region, and before entry into the reservoir beneath the volcano. An average chemical composition of the analysed Bagana andesites has major-element values close to those of the mean for more than 800 analysed late Cainozoic volcanic rocks from Papua New Guinea, and is proposed as a reference andesite composition for comparative studies.

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Title Andesites of Bagana volcano, Papua New Guinea: chemical stratigraphy, and a reference andesite composition
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/en/dataset/81834011-7dc0-4046-a856-c10554f7cbf4
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
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Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Andesites of Bagana volcano, Papua New Guinea: chemical stratigraphy, and a reference andesite composition". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/andesites-of-bagana-volcano-papua-new-guinea-chemical-stratigraphy-and-a-reference-andesite-com