Magnetic Field Survey of Macquarie Island Oceanic Crust

Macquarie Island's unique subaerial exposure of oceanic crust was surveyed using a GEM Systems GSM-19 Overhauser Magnetometer. The dataset contains magnetic intensity readings and rock sample information from the Bauer Bay to Boot Hill area, collected on 200 m line spacings. Data collection was conducted by the Australian Antarctic Data Centre (AU_AADC) during the 2008-2009 field season.

Use Cases

• Map active fault zones across the island using spatial variations in the Magnetic Intensity (nT) field.
• Determine the three-dimensional extent of hydrothermal alteration by correlating Rock Type with Magnetic Intensity (nT) lows.
• Correlate on-island geology with offshore data by analyzing the geospatial Easting and Northing coordinates of survey lines.
• Resolve complex geologic structure by interpreting magnetic anomalies across five principal study sites, including Prion Lake and Waterfall Lake.
• Validate magnetic character interpretations by cross-referencing the Magnetic Intensity (nT) data with rock samples from the subsidiary dataset.

Strengths

• Data collected with a specialized GEM Systems GSM-19 Overhauser Magnetometer, a standard instrument for high-precision magnetic surveys.
• Survey designed with systematic 200 m line spacings across the Bauer Bay to Boot Hill area for consistent spatial coverage.
• Project integrates ground- and air-based magnetic/electromagnetic surveys with follow-up geological investigations for multi-method validation.
• Focus on five principal study sites provides targeted analysis of specific magnetic low formations.

Limitations

• The dataset's temporal coverage is limited to a single primary field season (2008-2009), with the 2007-2008 season postponed.
• The sample size for rock samples used to check magnetic character is described as a 'small set', limiting statistical validation.
• Data collection was constrained by the rabbit eradication program on Macquarie Island, potentially affecting the original survey scope.

Provenance

Source

Australian Antarctic Data Centre (AU_AADC), accessed via NASA Earthdata.

Collection Method

Ground-based magnetic survey using a GEM Systems GSM-19 Overhauser Magnetometer on 200 m line spacings.

Time Range

2008-2009

Freshness

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Geography

Macquarie Island, specifically the Bauer Bay to Boot Hill area and five principal study sites, extending ~5 km from the island.