Symbols, units, constants and abbreviations used in this topic - Chemical Fundamentals of Geology and Environmental Geoscience - page 245

G molar free energy p i partial pressure of component i in a gas mixture

G universal gravitational constant (when printed

bold in this topic).

P load pressure, in pascals (Pa), megapascals

(MPa = 10 6 Pa) or gigapascals (GPa = 10 9 Pa)

Ga 'giga-annum' = 1 billion years = 10 9 years pH = −log 10 a H + (measure of acidity/alkalinity)

h height in m p H 2 O partial pressure of H 2 O in a gas mixture (e.g.

air), in same units as P H molar enthalpy

k rate constant q ionic charge, measured as a multiple of the

charge on an electron

K equilibrium constant

K i A partition coefficient describing the distribution

of element i between melt and mineral A.
See Box 9.1*

r (a) radial co-ordinate; (b) ionic radius (Box 2.6),

in pm (picometres = 10 -12 m)

S molar entropy

L litre (see dm 3 ) t time, in seconds, minutes, years (a), thousands

of years (ka) or millions of years (Ma) L length of guitar string (Equation 5.1)

ln natural logarithm = log e t 1/2 half-life

m mass T temperature, in °C or kelvins (K)

Ma 'mega-annum' = 1 million years = 10 6 years

v velocity

meq milliequivalents

x spatial co-ordinate

n+ nominal cation charge in atomic charge units* x a the mass proportion (0 < x a < 1.00) of component

(e.g. mineral) a in a mixture

n D number of daughter nuclei present in a

sample* X (a) composition in general terms; (b) composi-

tion of a mineral expressed in molar propor-
tions of its end-members*

n P number of parent (radionuclide) nuclei present

in a sample*

N neutron number (Box 10.1)*

y years

N c co-ordination number (Table 7.1)*

y spatial co-ordinate, transverse displacement of

guitar string (Equation 5.1)

p number of non-bridging oxygens per silicon

atom in a silicate crystal structure - a measure
of polymerization*

z spatial co-ordinate

Z atomic number*

*Dimensionless quantity.

Greek and other symbols (in Greek alphabet order)

α alpha notional stirring rate in heterogeneous kinetics experiment (Equation 3.4)

α 2 + alpha-particle

4 He nucleus, consisting of 2 protons and 2 neutrons

β - beta beta-particle = high-energy electron emitted from a nucleus

β + positron ( antimatter particle equivalent to electron)

δ 18 O delta 18 O

18 O/ 16 O ratio in a mineral or rock, expressed as the positive or negative deviation in parts
per thousand (‰ = 'per mil') from the 18 O 16 O value in a reference material (see Glossary)

Δ G delta † - G free energy change accompanying a reaction

Δ H delta † - H ethalpy change accompanying a reaction

Δ S delta † - S entropy change accompanying a reaction

Δ T delta † - T temperature change, degree of supercooling (=T − T solidus ) in °C

η eta viscosity (Equations 3.14 and 3.15)

λ lamda (a) wavelength; (b) radioactive decay constant

v nu neutrino

v nu-bar anti-neutrino (antimatter particle)

† These are the capital forms of the relevant Greek letter.