Screening Methodology & Standards

The screening engine operates on an equal-area hexagonal global discretisation mesh with a nominal spatial resolution of 0.1° (~11 km cell aperture). Hexagonal cell topology ensures equidistant neighbour adjacency and eliminates orthogonal pole distortion common in equirectangular rasters.

Each hexagonal cell serves as a vertically discretised column evaluating heat conduction, radiogenic crustal production, and boundary heat flow from the surface (0 km) down to the thermal base of the lithosphere.

Subsurface temperatures are modeled using steady-state and transient 1D/3D conductive-convective heat transport:

• Surface Boundary: Mean annual surface air temperatures normalized across global meteorological stations (baseline 15°C reference).
• Upper Crustal Heat Production: Radiogenic heat production (A) derived from global gamma-ray spectroscopy, lithological mappings, and granitic basement geochemistry.
• Curie Depth Isotherm: Aeromagnetic anomaly inversions constraining the 580°C titanomagnetite demagnetization isotherm.
• Moho & Lithosphere Boundaries: Crustal thickness constraints from global seismic tomography (CRUST1.0 / LITHO1.0).

Thermal energy in place (Heat in Place) is calculated volumetric-by-cell between 3.0 km and 7.0 km depth above a reference abandonment baseline of 80°C using standard volumetric thermodynamics:

Where ρ is rock bulk density (~2,650 kg/m³ for crystalline basements), C_p is rock specific heat capacity (~1,000 J/kg·K), and V is the accessible rock volume in each cell layer. Values are expressed in Zettajoules (1 ZJ = 10²¹ Joules).