endmember

A member at one end of a range or series made up of similar members.

Most significant is the observation that the vaporous for the more volatile end member occupies a decreasingly smaller portion of the diagram as the other end member becomes less volatile. Ultimately, when the less volatile end member is essentially involatile, the vaporous of the volatile end member may become microscopically small.

The physicochemical processes that control the estuarine filter must therefore be considered to operate in terms of a framework involving particulate-dissolved recycling associated with three estuarine end-members, i.e. river water, sea water (which may consist of more than one component end-member), and sediments.

A mineral that occurs at one end in a range of solid solutions.

This group of tetragonal silicates seems to form a graduated series from akermanite to gehlenite, the constitution of the two end[-]members being (where R = Ca, with less Mg, Mn, Fe, Na₂): / Akermanite, R₄Si₂O₁₀, or R₃(RSi)Si₂O₁₀, / Gehlenite, R₃Al₂Si₃O₁₀, or R₃(Al₃)Si₃O₁₀, […]

These data may therefore represent mixtures of gases from two (or more) distinct sources. One endmember appears to be slightly enriched in ⁸⁴Kr and ¹³²Xe relative to the vug quartz fluids; the other endmember is relatively enriched in ³⁶Ar.