Foundations

Fold geometry includes limbs, hinge/axis and axial surface; antiform/synform describe shape while anticline/syncline also depend on stratigraphic order.

Strike is the bearing of a horizontal line in a plane; dip is the maximum inclination from horizontal, perpendicular to strike, with direction specified.

Superposition constrains age order in an undisturbed depositional sequence; inclusions predate their host, and cross-cutting features postdate what they cut.

Fossil assemblages can constrain relative age and depositional environment through observed succession and known ecological context.

Grain size, sorting, sedimentary structures, composition and fossils together constrain depositional processes and environments.

Isostasy describes buoyancy-related balance of lithospheric columns over a deformable mantle in an appropriate model.

Silicate structures organize silicon–oxygen tetrahedra as isolated units, chains, sheets or frameworks.

Rock can begin melting without every component entering the liquid.

Crystallizing minerals remove selected chemical components from a melt.

Metamorphism changes mineral assemblage and texture under changed pressure, temperature, fluid and deformation conditions without requiring bulk melting.

Mechanical weathering changes fragment size; chemical weathering transforms or dissolves minerals through reactions such as hydrolysis and oxidation.

A distribution coefficient relates one species' concentrations in two specified coexisting phases.

In homogeneous constant-D batch melting, mass balance and equilibrium give melt enrichment Cℓ/C₀=1/[D+F(1−D)].

Streams carry bed load, suspended material and dissolved solutes through different processes.

Porosity measures pore-space fraction, while hydraulic permeability/conductivity concerns connected flow under stated fluid conditions.

Groundwater exchanges dissolved species with aquifer minerals and surfaces.

Glacier accumulation and ablation determine a mass budget; an equilibrium line separates zones in the specified surface-balance picture.

Moving ice can abrade and pluck bedrock, while transported debris can be deposited directly as till or sorted by meltwater.

Relative sea level is water level measured against local land.

When vertical acceleration is negligible, the vertical pressure gradient balances gravity: ∂p/∂z=−ρg for upward z.

For sufficiently slowly varying large-scale flow away from strong friction, horizontal pressure-gradient and Coriolis accelerations can approximately balance.

For an ideal dry gas with constant heat capacities, potential temperature θ=T(p₀/p)^(Rd/cp) is conserved in reversible adiabatic parcel motion.

Water-vapour amount and relative humidity are distinct; relative humidity compares vapour pressure with a specified saturation value at the current temperature.

Seawater density depends on temperature, salinity and pressure.

In the steady idealized surface Ekman layer, vertically integrated mass transport is ME=τ×ẑ/f.

Spatially varying wind stress can cause Ekman convergence/divergence and force interior ocean circulation.

Dissolved inorganic carbon includes aqueous CO₂/carbonic-acid convention, bicarbonate and carbonate.

Natural archives such as ice, sediments, corals and tree rings record properties related to past environments.

For a balanced reaction with signed stoichiometric coefficients νᵢ, the reaction quotient is the product of activities raised to those coefficients.

The molar Gibbs energy of a reaction at its current composition is ΔᵣG = ΔᵣG° + RT ln Q.