U–Pb SATURN

U–Pb Saturn is a robust, non-commercial data-reduction platform designed for geochronologists working with LA–ICP–MS U–Pb datasets. Developed in Python, Saturn provides a self-contained environment for processing data from both single-collector and multi-collector ICP-MS instruments. It supports datasets generated by a broad range of analytical platforms, including Thermo Scientific iCAP, Neoma, Neptune and Element systems, Agilent ICP-MS instruments, and Nu Instruments AttoM.

Saturn integrates data processing, visualization, and interpretation within a single interactive environment. Individual analyses are displayed simultaneously as background-corrected, time-resolved isotope signals and corresponding geochronological plots, including Tera–Wasserburg and Wetherill concordia diagrams and U–Pb/Pb–Pb isochrons. Changes to signal or background intervals are immediately propagated through the data-reduction workflow, allowing users to evaluate the effect of data selection directly on calculated ratios, ages, uncertainties, and graphical results.

A central feature of Saturn is the close interaction between its signal window, analytical tables, reference-material calculations, and geochronological plots. Users can inspect individual analyses, identify problematic intervals, modify background and signal regions, reject unsuitable portions of an analysis, and immediately evaluate the resulting geochronological information. This synchronized approach is particularly useful for complex minerals and heterogeneous datasets where automated integration alone may overlook important analytical features.

Saturn is also designed for large analytical sequences, supporting datasets containing up to approximately 1,000 analyses. Reference materials and unknowns can be selected interactively, and Saturn provides tools for fractionation correction, drift evaluation, uncertainty propagation, and rapid reassessment of analytical selections. Its dynamic processing environment also allows data to be inspected during an analytical session, providing a useful tool for real-time quality control during LA–ICP–MS acquisition and helping identify analytical problems before a run is completed.

The software is designed around simplicity and portability. Saturn operates directly from its software folder and does not depend on additional commercial data-reduction packages. The Windows version can therefore be transferred between compatible computers without activation keys or conventional installation procedures. A macOS version is under development.

U–Pb Saturn is freely available for download, together with instructional videos demonstrating software setup, data import, reference-material selection, data reduction, optimization, and interpretation. The objective is to provide the geochronology community with a flexible, transparent, and instrument-independent environment for reducing and evaluating LA–ICP–MS U–Pb data.

Evolution of U–Pb Saturn

U–Pb Saturn has evolved progressively from a straightforward U–Pb data-reduction program into a more integrated and interactive platform for LA–ICP–MS geochronology. Each version has focused on reducing manual operations, improving interaction with large analytical sequences, and allowing users to evaluate and modify their data directly through the graphical interface.

U–Pb Saturn 2.06 – Current Version

Version 2.06 is the most advanced release of U–Pb Saturn to date and incorporates several tools designed to make data reduction faster, more automated, and more interactive.

Major developments include:

• Auto-Selection of reference materials and samples. Users can search for analyses by typing a partial or complete name. Matching analyses are selected dynamically as the text is entered, greatly simplifying navigation through large analytical sequences.
• Laser-log integration. Laser-ablation logs can be imported and used to associate meaningful analysis names with the corresponding ICP-MS files, facilitating the reconstruction and organization of analytical sequences.
• Automated and interconnected plotting. Signal selection, data reduction, tables, and geochronological plots are dynamically linked. Changes made during data processing are automatically propagated to the relevant plots, allowing the effect of each modification to be evaluated immediately.
• Interactive concordia editing. Individual analyses can be selected and removed directly from the concordia diagram, avoiding the need to locate the corresponding analysis manually in a table or sample list.
• ROI selection tools. The Region of Interest (ROI) tool allows groups of data points to be selected directly on the concordia diagram. Points within a defined region can be identified and cropped interactively, providing a rapid way to isolate coherent age populations or remove unwanted analyses.
• Improved large-dataset handling. The combination of automated selection, linked graphical windows, laser-log integration, and interactive editing makes Version 2.06 particularly suited to large and complex analytical datasets.

The development of Saturn has therefore moved increasingly toward a graphically driven workflow. Rather than treating data reduction, inspection, and interpretation as separate steps, Version 2.06 connects them within the same environment: users can load an analytical sequence, assign reference materials and samples, perform corrections and uncertainty propagation, inspect time-resolved signals, and interact directly with concordia plots while the results are continuously updated.

The central philosophy of Saturn 2.06 is that U–Pb data reduction should remain transparent and under the control of the geochronologist, while repetitive operations are automated wherever possible.

Downloading and Installing

Saturn is designed for simplicity, portability, and broad instrument compatibility. It supports datasets generated by major ICP-MS platforms, including Thermo iCAP, Neoma, Neptune, and Element systems, as well as Agilent ICP-MS and Nu AttoM instruments. Saturn requires no conventional installation and runs directly from its folder, allowing it to be easily transferred between Windows computers without activation keys or complex setup procedures. This portability provides considerable flexibility for laboratory and data-reduction workflows. A macOS version is currently under development to further expand accessibility. To start using Saturn, users simply download the software, place it in the desired directory, and follow the step-by-step video tutorials provided with the software.

Download Saturn using the link below.

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DOWNLOAD SATURN 2.05 or 2.06 – WINDOWS 7, 10, 11 – 64 and 32 bits

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Saturn 2.04 Test Drive Files – Element – U-Pb Geochron

Saturn 2.03 Test Drive Files – AGILENT 8800 U-Pb Geochron

Saturn 2.03 Test Drive Files – ELEMENT 2 U-Pb Geochron

Saturn 2.05 – Detrital Zircons- Data Reduction

Getting Started: Loading and Reducing U–Pb Data in Saturn

Saturn follows a sequential workflow in which ICP-MS data are loaded, analytical names can be assigned from a laser log, reference materials and unknown samples are selected, and the appropriate correction and uncertainty-propagation strategy is then applied.

1. Load the ICP-MS Data

Start by loading the analytical dataset using the Load Data function. Select the files generated during the ICP-MS analytical session.

Saturn supports datasets from several single- and multi-collector ICP-MS platforms, including Thermo Scientific iCAP, Neoma, Neptune and Element instruments, Agilent ICP-MS systems, and Nu Instruments AttoM.

Once loaded, Saturn reads the analytical files and builds the analytical sequence used throughout the data-reduction procedure.

2. Load the Laser Log

If a laser log is available, load it using the Laser Log function.

The laser log allows Saturn to associate the ICP-MS files with the analysis names recorded during the laser-ablation session. This is particularly useful when the original ICP-MS filenames do not contain meaningful sample or reference-material names.

After loading the laser log, check the resulting analytical sequence and confirm that the laser analyses are correctly matched to the corresponding ICP-MS files before continuing.

3. Select Reference Materials and Samples

The analyses are displayed in the Reference Material and Sample lists.

Select the analyses that will be used as reference materials and those that will be treated as unknown samples. Analyses can be selected manually or by using Saturn’s Auto-Selection tool.

With Auto-Selection, simply type part of the desired name—for example GJ, GJ1, or PLES. Matching analyses are selected dynamically as the text is entered.

Before proceeding, verify that the correct analyses have been assigned to the RM and Sample groups.

4. Choose the Primary Reference Material

After selecting the reference-material analyses, choose the primary U–Pb reference material from the Reference Material combo box.

The selected material provides the accepted isotopic and age values used by Saturn to calculate the correction factors applied to the unknown analyses.

The material selected in the combo box must correspond to the reference-material analyses selected in the RM list.

5. Choose Average or Drift Correction

The next step is to determine whether the dataset should be corrected using an average correction factor or a time-dependent drift correction.

For shorter analytical sequences or datasets showing no significant temporal variation, an average correction factor may be sufficient.

For longer analytical sessions, first examine the behaviour of the selected reference materials through time. If enough reference-material analyses are distributed throughout the sequence to define temporal changes reliably, Drift Correction can be activated.

Saturn then models the evolution of the correction factor through the analytical sequence and applies the time-dependent correction to the unknown samples.

6. Select the Polynomial Degree

When Drift Correction is enabled, select the appropriate polynomial degree.

The polynomial should reproduce the observed temporal evolution of the reference-material correction factors without unnecessarily fitting analytical scatter.

Use the lowest polynomial degree that adequately describes the drift. Increasing the polynomial order should only be considered when the distribution and number of reference-material analyses clearly support the additional complexity.

The fitted drift curve should always be inspected graphically before accepting the correction.

7. Apply Uncertainty Propagation

Once the correction strategy has been established, select the appropriate uncertainty-propagation method.

Saturn combines the analytical uncertainty of individual measurements with the additional uncertainty associated with reference-material reproducibility and the selected correction procedure.

The resulting propagated uncertainties are then incorporated into the corrected isotope ratios and calculated U–Pb ages used in the final tables and geochronological plots.

Recommended workflow

Load ICP-MS data → Load laser log → Check analytical sequence → Select RMs → Select samples → Choose primary reference material → Evaluate RM behaviour → Choose Average or Drift correction → Select polynomial degree when required → Apply uncertainty propagation → Inspect corrected ages and plots.

The important message for users should be: do not choose Drift simply because the option exists. First look at the number and temporal distribution of the RMs. The reference materials need to constrain the evolution of the correction factor across the analytical sequence; otherwise, Average mode is the more defensible correction.

Auto-Selection Feature in Saturn 2.0

The Auto-Selection feature in Saturn 2.0 provides a fast and intuitive way to select Reference Materials (RMs) and Samples during U–Pb data reduction. It is particularly useful for large analytical sequences, eliminating the need to manually search through long lists of analyses.

How It Works

1. Activate Auto-Selection
   • Click the Auto Select RM or Auto Select Sample button.
   • A search field immediately appears and is ready for input.
2. Live Search and Selection
   • Begin typing a partial or complete reference-material or sample name, such as "GJ", "GJ1", or "PLES".
   • Saturn searches the corresponding list as each character is entered.
   • All analyses containing the entered text are automatically highlighted and selected.
   • There is no need to press the Auto Select button a second time.
3. Immediate Data Processing
   • The selected analyses are immediately passed to Saturn’s data-reduction workflow.
   • Changing the search text dynamically updates the selection, allowing groups of analyses with common names to be selected rapidly.
4. Close the Search Field
   • Once the desired analyses have been selected, simply press Enter or click elsewhere in the interface.
   • The search field disappears automatically, keeping the workspace clean and allowing the user to continue directly with data reduction.

This live-search approach makes the selection of large groups of reference materials and samples considerably faster, particularly when working with extensive analytical sequences.

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Drift Correction in Saturn 2.05

Drift corrections compensate for long-term signal changes due to laser fluctuations, instrumental drift, or changing ablation conditions. Saturn 2.0 allows users to apply polynomial drift correction to correct these systematic changes over longer timescales.

🔹 Polynomial Drift Correction

• This method adjusts for drift by fitting a polynomial to long-term trends in the data.
• Useful when the signal slowly shifts over multiple analyses due to instrument instability or changes in laser performance.

🔹 When to Apply Drift Correction

• When data shows a progressive shift in isotope ratios over time.
• If reference materials indicate a systematic bias in multiple analyses.

Saturn 2.05 – Fractionation Corrections

In Laser Ablation, fractionation correction is essential for accurate isotopic analysis, as it helps address laser-induced variations that occur during ablation. The three types of fractionation corrections implemented here—Linear, Exponential, and Polynomial—apply different mathematical approaches to refine the Pb/U ratio measurement. Here’s a breakdown in plain language:

1. Linear Fractionation Correction

• Goal: This approach fits a straight line to the Pb/U signal data, assuming that fractionation occurs linearly over time.
• How It Works: It performs a simple linear regression on the signal data points (values above a certain threshold), creating a correction by adding or subtracting from each data point based on the trend. The corrected values help smooth out any deviations that might have occurred during analysis.
• When to Use: Linear correction is best when fractionation appears stable and increases or decreases consistently, without rapid fluctuations.

2. Exponential Fractionation Correction

• Goal: This approach models fractionation as an exponential function, which is useful when the rate of fractionation isn’t constant but follows an accelerating or decelerating trend.
• How It Works: It calculates a corrected Pb/U ratio by fitting an exponential curve to the signal data, assuming fractionation behaves in a way that intensifies over time. This method is more flexible for samples where the fractionation rate changes gradually.
• When to Use: Exponential correction is ideal when fractionation builds up over time, such as when heat or other conditions cause accelerating effects on isotopic ratios.

3. Polynomial Fractionation Correction

• Goal: This correction method uses a higher-degree polynomial to capture more complex fractionation patterns, accommodating non-linear changes with more precision.
• How It Works: A polynomial curve, often quadratic or cubic, is fitted to the data to represent fractionation patterns that might oscillate or show irregular changes. This flexibility allows correction in datasets where the fractionation rate varies in complex ways.
• When to Use: Polynomial correction is suitable for datasets with unpredictable or fluctuating fractionation, especially when other models don’t fit well.

Saturn 2.0 – Example of Fractionation and Drift Correction for Long Dataset

Watch the video first and learn the application of Fractionation and Drift correction using Saturn 2.0. Below is a clear explanation of what is important about fractionation correction and drift correction in LA ICP MS.

The Fractionation Correction options in Saturn can be accessed directly from the main window, as seen in the bottom-right section of the left panel under “Fractionation Correction.”

Each correction method has a unique advantage depending on the fractionation pattern in the sample, allowing Saturn to apply the most accurate correction for robust isotopic analysis.

1. No Correction: This option leaves the data uncorrected, which might be suitable if fractionation is negligible or has already been accounted for elsewhere.
2. Linear Correction: This applies a straightforward, linear correction, assuming that fractionation changes consistently over time. It’s useful when fractionation appears stable and does not fluctuate significantly.
3. Exponential Correction: This option models fractionation as an exponential process, accounting for cases where fractionation accelerates or decelerates over time.
4. Poly Correction: This uses a polynomial function to correct fractionation, ideal for complex fractionation patterns that are non-linear and may vary in unpredictable ways.

These options allow users to select the most appropriate correction based on the behaviour of fractionation in their dataset, ensuring accurate isotopic measurements in their analysis.

In Saturn, the fractionation behaviour can be visualised and checked using the Fractionation window. This window provides a graphical representation of the isotopic ratios over time, helping users assess the consistency and trends in fractionation for each analysis.

2. Exponential Fractionation Correction

🔹 Goal: This method assumes that fractionation follows an exponential trend over time, where the rate of change decreases progressively.

🔹 How It Works:

• The Pb/U ratio is modelled using an exponential function, meaning the correction factor is determined based on a decaying or accelerating fractionation rate.
• It fits the data to an exponential curve, adjusting each data point accordingly.
• The correction factor is applied such that it accounts for strong initial fractionation that stabilizes over time, a behaviour commonly observed in laser ablation.

🔹 When to Use:

• Ideal for short, high-intensity laser sessions where fractionation starts strong and decreases over time.
• Useful when the laser-induced fractionation shows a rapid initial drop followed by stabilisation.

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3. Polynomial Fractionation Correction

🔹 Goal: This approach captures non-linear variations in fractionation by fitting a higher-order polynomial curve to the Pb/U ratio trend.

🔹 How It Works:

• Instead of assuming a straight-line or exponential behaviour, it uses a polynomial function (e.g., quadratic, cubic, etc.) to model complex fractionation trends.
• This method can correct for multiple shifts in fractionation behavior over the ablation duration.
• Higher-order polynomial fits allow for capturing more dynamic and irregular fractionation trends.

🔹 When to Use:

• Best for datasets where fractionation behaviour is irregular or does not follow a simple linear or exponential trend.
• Ideal for cases where fractionation varies in multiple directions (e.g., starts increasing, then stabilizes, then increases again).

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Choosing the Right Fractionation Correction in Saturn 2.0

Correction Type	Best For	Trend Assumption
Linear	Gradual, stable fractionation	Straight-line change over time
Exponential	Fast-changing fractionation at the start	Rapid initial change, then stabilizing
Polynomial	Irregular fractionation patterns	Complex, multi-directional changes

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Key Features of the Fractionation Window:

• Data Source and Run Name: The top of the Fractionation window allows you to select a specific data source and run name to focus on a particular sample or analysis.
• Isotopic Ratio Options: You can select different isotopic ratios (e.g., 207Pb/206Pb, Th/U, 206Pb/238U) to visualise, allowing you to monitor changes in each ratio across the measurement sequence.
• Normalised Ratios Plot: This graph shows the selected isotopic ratio as a function of time or scan sequence, displaying how fractionation changes during the analysis. The trend line helps you see if the fractionation is stable, increasing, or decreasing, which can guide your choice of fractionation correction.

Using this window, you can evaluate whether linear, exponential, or polynomial correction would best address the observed fractionation trend, ensuring that your corrected data accurately represents the true isotopic composition of your samples.

For fractionation correction in U-Pb Saturn, the four options likely involve the following:

1. No Correction: The raw data is used as-is without any adjustment for fractionation effects.
2. Linear Correction: Applies a simple linear model, assuming that the fractionation effect changes consistently over time or across the dataset.
3. Exponential Correction: Models the fractionation as an exponential decay or growth, accounting for non-linear trends that follow a specific exponential pattern.
4. Polynomial Correction: Fits a polynomial curve to the fractionation data, capturing more complex, non-linear fractionation effects with greater flexibility.

Saturn Windows 10 – Older Versions

SATURN FOR WINDOWS 8 AND 10

Version 1.1 https://www.dropbox.com/s/wfmnoor560k5pce/SATURN%20-%202022-10-13%20-%20WITHOUT%20CONSOLE.zip?dl=1

Version 1.2 – https://drive.google.com/file/d/16aFlmpsrv9dcM73sVSXeYpG3b1VcEdKB/view?usp=sharing

Version 1.3 – https://drive.google.com/file/d/1wOUwchTVpDynQM_58MgdrupGzGNKDlFM/view?usp=sharing

IMPORTANT TIPS:

1- SATURN DOES NOT NEED TO BE INSTALLED. JUST COPY THE FOLDER TO YOUR DESKTOP AND RUN IT.

2- WHEN LOADING SATURN FOR THE FIRST TIME, YOU WILL HAVE TO WAIT FOR 2 MINUTES FOR THE SOFTWARE TO GET STARTED

Much Older Versions

Saturn 1.0 Test Drive Files

U-Pb in Zircon analysed with a Neptune plus.

Here we used GJ 1 as the primary reference material. The certified reference values for GJ 1 are already loaded in the software. The secondary RM is the Plesovice zircon

After watching the video above you should try it yourself.

GJ 1 DATA FILES FOR DOWNLOAD

https://air.app.br/wp-content/uploads/2023/02/GJ-DATA.zip

U-Pb in Monazite analysed with an Element 2.

Here we used Vermillion Monazite as the primary reference material. The certified reference values for Vermillion are already loaded in the software.

Note that the procedure is the same as above. The big difference here is that we show that some of the RM analyses were not good due to small defects in the RM crystal. So we removed the faulty analyses to improve the data quality.

After watching the video above you should try it yourself.

Adding new reference material is easy and straightforward. Go to the Ref Material Tab, add the name plus the certified values on the reference material window and click ADD. You can remove by clicking on remove, and change by clicking on the existing ref material, and changing the certified values. Follow the video and try it with the dataset above.