Two submarine volcanic cones, 120 km apart and rising to depths of 750 m and 900 m, were mapped and dredged on the Lord Howe Rise. Volcanic rocks are predominantly altered hyaloclastites with minor basalt, and interbedded micrites indicate formation in the late Early Miocene (~16 Ma). Ferromanganese crusts up to 7 cm thick were sampled, with growth rates averaging 3 mm/m.y. and varying chemical compositions.
Use Cases
- Modeling intraplate hotspot magmatism based on cone alignment and gravity high correlations mentioned in the description.
- Analyzing ferromanganese crust growth rates and hydrothermal influence based on reported Mn:Fe ratios and metal content.
- Studying Miocene paleoenvironmental changes based on foraminifera indicating cool water deposition shifting to warm water infill.
- Correlating volcanic seamount fields with continental crust thickness as suggested by the described genesis model.
Strengths
- Includes specific geochemical data such as ferromanganese crust thickness (up to 7 cm) and metal content limits (e.g., cobalt not exceeding 0.25%).
- Provides precise spatial and depth details for two sampled cones, including their alignment (NNW) and separation (120 km).
- Offers a constrained temporal context with micrite dating to the late Early Miocene (~16 Ma) and inferred growth rates (3 mm/m.y.).
Limitations
- Row count is unknown, which may limit suitability assessment.
- Column-level documentation is absent; field semantics must be inferred after download.
- Data may reflect geographic bias inherent to data_gov_au, focusing on a specific region of the Lord Howe Rise.
Provenance
- Source
- Australian Ocean Data Network
- Collection Method
- Multibeam sonar swath-mapping and dredge sampling.
- Time Range
- Late Early Miocene (~16 Ma) to Pliocene, with sampling in the modern era.
- Freshness
- Last updated 2026-06-27 18:13:16.843897; freshness should be verified.
- Geography
- Northeastern Lord Howe Rise, approximately 23-24°S.