Late Cretaceous Basalt-Rhyolite Geochemistry in Central Queensland

Geochemical and isotopic data from an alkali basalt to peralkaline rhyolite suite emplaced around 77 million years ago in central Queensland. The dataset, from Geoscience Australia, combines field mapping, petrography, geochemistry, isotopic analysis, and geochronology on the Alton Downs Basalt and Mount Hedlow Trachyte. It characterizes a volcanic field formed in a failed continental rift during the breakup of Gondwana.

Use Cases

• Model HFSE enrichment trends using trace element data like Zr, Nb, Ta, and HREE concentrations across the basalt-to-rhyolite suite.
• Correlate Sm–Nd isotopic compositions (ƐNd values) with geochemical signatures to infer mantle source characteristics and crustal assimilation.
• Classify magmatic evolutionary paths (agpaitic vs. miaskitic) using mineralogical indicators like aenigmatite, zircon, or monazite presence from petrographic data.
• Analyze the spatial distribution of lava flows, intrusions, and cryptodomes from field mapping to understand volcanic field architecture.

Strengths

• Integrates multiple analytical methods: field mapping, petrography, geochemistry, isotopic analysis, and geochronology.
• Provides a temporally constrained case study with a precise emplacement age of approximately 77 Ma.
• Characterizes a complete magmatic suite from alkali basalt to peralkaline rhyolite, showing differentiation paths.

Limitations

• Sample size and specific row/column counts are not provided in the description.
• The felsic rocks did not reach extreme fractionation, resulting in modest HFSE content compared to other regional suites.
• Data format and accessibility details (e.g., file structure, download links) are not specified in the input.

Provenance

Source

Geoscience Australia Data

Collection Method

Combined field mapping, petrography, geochemistry, isotopic analysis, and geochronology.

Time Range

Late Cretaceous, approximately 77 million years ago.

Freshness

null

Geography

Central Queensland, Australia (Alton Downs Basalt and Mount Hedlow Trachyte).