IGL

Isotope Geochemistry Language, a text format for isotopic process models



Describes IGL 0.5. Page revision 1.0, 2026-07-31. 14 databases, 180 entries.

Fractionation databases

14 databases, 180 entries. Every numeric value carries a citation, without exception. A factor whose source cannot be named is a factor nobody can check, and a database of those is a convenience that costs more than it saves.

Published under CC-BY-4.0. Each entry additionally cites its own source, and that citation is what should appear in a paper: the database is how a value is found, the paper is what justifies it.

ElementRatioEntriesSourcesMechanisms
Cd114Cd/110Cd1615adsorption, dissolution, evaporation, precipitation, redox, uptake
Cr53Cr/52Cr2624adsorption, dissolution, oxidation, precipitation, reduction
Cu65Cu/63Cu1918adsorption, dissolution, evaporation, precipitation, reduction, uptake
Fe56Fe/54Fe2828adsorption, dissolution, evaporation, oxidation, precipitation, redox, reduction
Li7Li/6Li55adsorption, dissolution, evaporation, precipitation
Ni60Ni/58Ni65adsorption, redox, uptake
Pb206Pb/204Pb11dissolution
Pb207Pb/206Pb21reduction
Pb208Pb/206Pb31reduction
Sb123Sb/121Sb3823adsorption, dissolution, evaporation, ligand_exchange, oxidation, redox, reduction, uptake
Se82Se/76Se98adsorption, dissolution, oxidation, reduction, uptake
Sr88Sr/86Sr77adsorption, dissolution, precipitation, uptake
W186W/184W21adsorption
Zn66Zn/64Zn1818adsorption, dissolution, evaporation, precipitation, redox, uptake

Files

FileSizeSHA-256
cd_114cd_110cd.igdb 17.6 KiB 1cea66725e899327…
cr_53cr_52cr.igdb 23.1 KiB 5edff0f74871d04b…
cu_65cu_63cu.igdb 19.4 KiB eb9892149863428f…
fe_56fe_54fe.igdb 31.1 KiB 4da3f241952d95ad…
li_7li_6li.igdb 4.9 KiB 2602c362633f80cf…
ni_60ni_58ni.igdb 5.4 KiB 9f430f615b7e1ba6…
pb_206pb_204pb.igdb 1.8 KiB d6b2a1030b2d0861…
pb_207pb_206pb.igdb 2.5 KiB 0b0657dbee41b8e3…
pb_208pb_206pb.igdb 3.2 KiB afaf99f3456fee08…
sb_123sb_121sb.igdb 19.8 KiB 0db9259e856f87c4…
se_82se_76se.igdb 10.4 KiB fc0fa5fad2e26bfb…
sr_88sr_86sr.igdb 7.9 KiB 25ef0415df7469fd…
w_186w_184w.igdb 1.9 KiB 35e3dd7cd28e63f6…
zn_66zn_64zn.igdb 19.1 KiB 1da23006111bb3c4…

A digest is published for each file because a model's provenance records the digest of the database it read. Two runs that disagree can then be traced to the data rather than argued about.

Using one

A model names a database and the engine resolves what the model left out.

DATABASE
    file "cr_53cr_52cr.igdb"

CONDITIONS
    temperature 15 C
    pH 7.0

A bare name is searched for: beside the model first, then IGL_DATABASES, then a databases directory near the executable. A name carrying a path is resolved beside the model and nowhere else. Model first is deliberate: an IGDB file is a model's own evidence and may travel with it, so a model that ships one always reads that one.

What the engine resolves is recorded. The intermediate representation carries the path a name was answered by and its digest, so a results file never leaves in doubt which data produced it.

How a query is answered

A query names the ratio, the mechanism and the two species, and carries the model's conditions. Entries covering those conditions are preferred to entries silent about them, which are preferred to entries that exclude them. Among those, the entry stating the most wins.

A tie is an error. Two entries equally applicable to one query mean the database has not decided, and an engine that chose would hide a disagreement in the literature behind a lookup. The message names the citations in conflict, so the choice can be made where it belongs, by the person writing the model.

Contributing an entry

An entry needs a ratio, a mechanism, the two species, a value, and a citation. An entry that cannot name its source cannot go in. The format is described in the companion formats, and corrections are welcome at colin.ferrari@igl-lang.org.