OR/18/005 Glossary

Evans, J A, Mee, K, Chenery, C A, Cartwright, C E, Lee, K A, and Marchant, A P. 2018. User guide for the Biosphere Isotope Domains GB (Version 1) dataset and web portal. British Geological Survey. (OR/18/005).

Definitions

Biosphere	The regions of the surface and atmosphere of the earth or another planet occupied by living organisms.
Count	The number of sample values used to define a category within an isotope domain.
Domain	Refers to the 3 different elements (Sr, O, S) and their isotope variations described in this dataset.
Hexagon	The shape of the cells in the map representing the isotope domains data.
Hydrosphere	Refers to atmospheric water (precipitation), surface and groundwater.
Interquartile range	Is a measure of statistical dispersion, being equal to the difference between 75th and 25th percentiles centred around the median of the sample, excluding statistical outliers.
Isotope	Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
Lower whisker	Represent the lower 25% of the data set around the median value, excluding statistical outliers.
Median*	Denoting or relating to a value or quantity lying at the midpoint of a frequency distribution of observed values or quantities, such that there is an equal probability of falling above or below it.
Maximum value	The highest value in a data set.
Mean*	The central value of a discrete set of numbers: specifically, the sum of the values divided by the number of values.
Minimum value	The lowest value in a data set.
Coastal Effects zone	The zone around the coast effected by precipitation containing dissolved S and Sr from sea spray aerosol with isotopic values comparable to marine values.
Soil parent material	A geological deposit over, and within which, a soil develops. Typically, the parent material is the first recognisably geological deposit encountered when excavating beneath the soil and represents the very-near-surface geology (see Lawley, 2011).
Statistical uncertainty	The margin of error of a measurement, when explicitly stated, and is given by a range of values likely to enclose the true value.
Subdomain	The subdivision of the isotope domain layers, based on geology (including soil parent material), age of deposit and geography, into zones of similar isotopic ranges.
Upper whisker	Represent the upper 25% of the data set around the median value.
1 Standard deviation (1SD)	A measure, for a set of data, of the spread from its mean. It is calculated as or the square root of variance by determining the variation between each data point relative to the mean.
1st Quartile (Q1*)	The lower half of the interquartile range representing the upper 25 to 50% of the data set, excluding statistical outliers.
3rd Quartile (Q3*)	The upper half of the interquartile range representing the upper 50 to 75% of the data set, excluding statistical outliers.

* Calculated using Excel functions.