A marine geophysical concept defining measurements and products used to characterize seafloor shape and subsurface structure. It governs acquisition, processing, and interpretation steps that convert instrument signals into interpretable maps and profiles. It does not establish material properties without calibration, integration with samples, and validation against independent observations. It materially affects understanding of tectonics, hazards, and sediment pathways by revealing geometry and stratigraphic patterns. The concept is generally stable, though instruments, processing methods, and resolution capabilities improve over time.

Principle

XRF scanning exploits characteristic fluorescent X-rays emitted by elements under excitation to record relative elemental intensities at fine spatial intervals, enabling rapid, high-resolution tracing of compositional changes without consuming the sample.

Demonstration

A core logging campaign that scans split sediment cores at 1 cm intervals producing elemental counts or normalized intensities for Ti, Ca, Fe, K and Sr that reveal event layers, compositional shifts and diagenetic signals when plotted versus depth.

Misapplication

Interpreting raw XRF counts as absolute concentrations without instrument-specific calibration curves, ignoring effects of water content, grain size or matrix, which leads to incorrect provenance or environmental conclusions.

Consequence

Appropriately executed surveys produce continuous geochemical logs that inform lithological correlation, event detection (volcanic ash, floods), provenance shifts and temporal change at resolutions often unattainable by discrete sampling.

Reversal

Discrete point XRF measurements on powdered, homogenised samples are the reverse approach: they provide calibrated concentrations at specific depths but miss the continuous, high-resolution stratigraphic context provided by scanning.

Boundary

Applies to non-destructive scanning measurements and their immediate QC metadata; excludes destructive laboratory elemental determinations (ICP-MS, AAS) used for absolute concentration calibration, and in-situ handheld XRF surveys of unconsolidated sediments unless depth registration is provided.

Semantic Tension

There is tension between maximizing spatial resolution and maintaining quantitative accuracy; high-resolution counts are powerful for relative change detection but require careful calibration and correction to support absolute geochemical interpretations.

Synthesis

An XRF Scanning Survey is a planned sequence of non-destructive, depth-registered XRF measurements that yields high-resolution elemental profiles to detect compositional changes, stratigraphic markers and guide further sampling or modelling.