delta_to_ratio: Convert delta value to isotope ratio

In jmerc13/LakeIsodrology: Lake isotope hydrology

Description

This function, delta_to_ratio takes a delta value, in per mille of either hydrogen or oxygen, and converts it to an isotope ratio [-], using a standard. Applicable standards include Vienna Standard Mean Ocean Water (VSMOW), Greenland Ice Sheet Precipitation (GISP), and Standard Light Antarctic Precipitation (SLAP).

Usage

delta_to_ratio(delta, element, standard = "VSMOW", unit)

Arguments

delta	An isotope delta value, in per mille.
element	Character value indicating either "Hydrogen" or "Oxygen".
standard	Character value indicating the acronym of the standard to be used: "VMSOW", "GISP", or "SLAP".
unit	Character value explicitly indicating if the input units are "decimal" or "permille".

Details

The relationship used to convert a given delta value to an isotope ratio:

{}^{A}R = \Bigg(\frac{δ^{A}X}{1000} + 1\Bigg) {}^{A}R_{Standard}

Where A indicates the isotope of element X, R is the ratio of the sample, and R_{Standard} is the isotope ratio of the standard being used.

Below are the values of each standard and its isotope ratio used in this function.

Standard	2H/1H	18O/16O
VSMOW	0.00015576	0.00200520
GISP	0.00012624	0.00195555
SLAP	0.00008902	0.00189391

VSMOw and SLAP standard information can be found at: https://nucleus.iaea.org/rpst/documents/VSMOW_SLAP.pdf

GISP standard information: https://nucleus.iaea.org/rpst/Documents/rs_GISP.pdf

Value

Unitless numeric value of the isotope ratio.

jmerc13/LakeIsodrology documentation built on May 5, 2019, 5:52 p.m.