Page of the day
Deposits in the Atlas
Every day, one page documented to at least 70% is featured here.
Specialised in non-traditional isotopes, from lithium to uranium.
Published isotope values for ore deposits and mining environments, reported against international reference materials with their uncertainty and their source, alongside fractionation factors and the tools to work with them. Everything is open to read, with no account needed.
Data last updated 5 November 2026
Page of the day
Every day, one page documented to at least 70% is featured here.
In your browser, or on your own computer
The database of published isotope values
Ore deposits, mining and environmental sites, fractionation experiments. Values are brought back to international standards, and the original scale, the uncertainty and the reference are kept.
Calculations and maps, with nothing to install
Work directly on the isotope data of the Atlas: geochemical and isotopic modelling, mapping. Everything runs in your browser and nothing is sent to a server. There is nothing to install.
A language for describing isotopic models
Reservoirs, processes, fractionation factors and the standard are written down in a plain text file that any compliant engine can run. The specification is under CC BY 4.0 and the reference engine under MIT.
Runs locally, results are signed
Offline desktop software for geochemistry, isotopes, modelling and reports. Results are saved in the ISOF format, signed by the laboratory and verifiable without IsoFind. The Essential edition is free.
Convert isotope signatures from one standard to another, so they can be compared directly.
Each conversion relies on a published offset between the two materials, with its uncertainty, and the page names the paper it comes from. When no offset has been published, the page says so and leaves the value on its original scale.
IGL
IGDB
ISOF
TITLE Chromium reduction in a closed system STANDARD standard NIST-SRM-979 0.11339 ratio 53Cr/52Cr RESERVOIR Groundwater volume 1 L Cr(VI) 1 umol/kgw delta53Cr 0 permil PROCESS Reduction type reduction reactant Cr(VI) product Cr(III) extent 0.6 FRACTIONATION Reduction isotope 53Cr/52Cr epsilon -3.5 OUTPUT variable Groundwater.Cr(III).delta53Cr
The file describes the system and leaves the solving to the engine. Anyone can read the assumptions back without reading code.
$ igl check modele.igl no diagnostics $ igl build modele.igl modele.iglir.json $ igl run modele.iglir.json modele.results.json
Check, build, run. The results file keeps the provenance of the model and of every value it used.
[database] name = "cr_53cr_52cr" igdb_version = "1.1" licence = "CC-BY-4.0" [[fractionation]] ratio = "53Cr/52Cr" process = "reduction" reactant = "Cr(VI)" product = "Cr(III)" epsilon = -3.5 uncertainty = 0.1 regime = "kinetic" temperature_range = [293.15, 293.15] material = "Reduction by magnetite (Fe3O4)" citation = "Ellis et al., 2002" doi = "10.1126/science.1068368"
The fractionation factors of the Atlas, exported one system at a time. Every entry keeps its citation, and an entry without a source is not exported. The IGL model next door can take its epsilon from here.
{ "version": "1.3", "header": { "lab_id": "ISO-REF-042", "timestamp": "2026-03-12T14:30:00Z" }, "data": { "element": "Pb", "206Pb_204Pb": 18.234, "207Pb_204Pb": 15.612, "uncertainty": 0.002, "purification_yield": 98.7 }, "signature": "304502210089..." }
Ratios, uncertainties and analytical metadata are signed together with the measurement. Any later change breaks the signature.
# pip install isof import isof cert = isof.load("resultat.isof") print(cert.is_valid()) # True
A reviewer or an auditor checks the file on their own computer, with no account and no connection.
IsoFind
The site does not follow its visitors from page to page and passes nothing on to ad networks or social media. Visits are counted, without trying to find out who makes them.
There is no advertising on the site or in the software, and no data is sold or handed over to anyone.
The workspace computes in your browser and the software works offline, so your measurements never leave your computer. Whatever you submit to the Atlas only goes in with your agreement, under your name, and under embargo if you ask for it.
ISOF, IGL and IGDB are public specifications. A file made with IsoFind can be read and checked with other tools, including on the day IsoFind no longer exists.
The Atlas
A value in the Atlas always points back to its publication, with the standard it is reported against, the mineral or matrix analysed and the uncertainty given by the authors. When the paper leaves one of these out, the page says so instead of filling it in.
A value only moves to another standard if an offset between the two materials has been measured and published. Otherwise it stays on its original scale, and the page shows it as it is.
The reference pages, the glossary, the charts and the standards conversion can be read without an account or any sign-up. The pages are the same for everyone.
The Atlas is released in numbered, frozen versions. A study can cite the exact version it used and find the same values again later.
IsoFind Atlas, isofind.tech/atlas, accessed [date], after [reference].
Please also cite the original publication of each value you use. It is given on the page, with its DOI.
They can go into the Atlas with their DOI and your name, after review. Datasets that are not published yet can be submitted under embargo from the workspace.
Submit dataIsoFind brings together several services around isotope geochemistry. The Atlas gathers published values for ore deposits, contaminated sites and fractionation, free to browse, with more than 8,100 reference pages in English and French. The IsoFind software is for working on your own measurements, offline. Free online tools such as the standards conversion and two open formats, ISOF (Isotopic Secure Open Format) and IGL (Isotope Geochemistry Language), complete it.
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