Where does aureole collide?

In geology a contact aureole is the ring, or halo, of surrounding rock whose minerals have been recrystallised by the heat of a nearby body of molten rock that cooled underground, forming zones that grade outward from the hot contact. The modern study of this zone dates to Goldschmidt's 1911 Die Kontaktmetamorphose im Kristianiagebiet, which mapped the mineral changes produced in the rocks around the intrusions of the Oslo region. Kerrick's 1991 Contact Metamorphism reviewed the heat flow, fluids, and chemical reactions that shape such aureoles. The referent is a physical volume of altered rock measured in the field, and it is unrelated to a painted halo of light around a saint or a bright zone of sky around the sun.[1][2]

Unit

One zone of altered rock around a single intrusion, described by its width and mineral zoning

Recovery means

Not applicable

Measured by

Mapped in the field and sampled for the marker minerals and reaction textures that define each zone

In atmospheric optics the solar aureole is the bright zone of sky immediately around the sun, produced when sunlight is scattered through small angles by aerosol particles and haze in the air. Green, Deepak, and Lipofsky's 1971 Interpretation of the Sun's Aureole Based on Atmospheric Aerosol Models showed how the brightness and shape of this zone can be read to infer the range of particle sizes suspended in the atmosphere. The referent is a pattern of scattered light in the sky, measured by pointing instruments near the sun, and it is a different thing from a ring of altered rock around an intrusion or a painted radiance around a holy figure.[3]

Unit

The brightness of the sky as a function of angle from the sun

Recovery means

Not applicable

Measured by

Recorded by sun photometers and sky radiometers that read sky brightness at small angles from the solar disc