The Arizona LaserChron Center is an NSF Community Facility that is designed to address problems in Earth Science through the generation of U-Th-Pb geochronologic data and complementary geochemical information by Laser Ablation ICP Mass Spectrometry. Our primary goals are as follows:

• Generate U-Th-Pb ages, Hf isotope ratios, and trace element concentrations of the best precision, accuracy, and spatial resolution possible from LA-ICPMS.

• Provide opportunities for researchers from around the world (and especially NSF-supported scientists) to use our instruments and expertise to address geologic problems.

• Drive the development of new techniques and applications of geochronology, thermochronology, and petrochronology.

• Build new cyberinfrastructure for data acquisition, analysis, and archiving.

• Use every aspect of facility operation as an opportunity to increase access to geochronology and build diversity and expertise among geochronologists and users of geochronology. 

The main instruments utilized at the Arizona LaserChron Center include a Nu Plasma multicollector ICPMS, a Thermo Element2 single-collector ICPMS, a Teledyne Iridia laser and two Analyte G2 lasers, and a Hitachi 3400N SEM. We are currently upgrading the EBSD/EDS capabilities of our SEM and acquiring a new Raman PL imaging system, and preparing to install new Thermo iCAP and Neoma mass spectrometers. 

Support for the Arizona LaserChron Center is provided by the NSF Instrumentation and Facilities Program (http://www.nsf.gov/geo/ear/if/facil.jsp). We operate as a Community Facility, available to all NSF-supported researchers and students as well as Earth scientists from around the world. During recent years we have supported the research of ~350 faculty members, graduate students and undergraduate students per year. Results of this research have been reported in an average of ~140 peer-reviewed publications per year. 

Check out our Welcome Video to learn more about the ALC.  Please contact George Gehrels (ggehrels@arizona.edu) or Mauricio Ibanez-Mejia (ibanezm@arizona.edu) (co-directors of the ALC) for general questions about the lab, or Mark Pecha (Manager of the ALC; mpecha@arizona.edu) for specific information about analytical methods, schedules, costs, letters of collaboration, etc. 

Please note that some links on our web page will not work if you are logged into other web systems -- just log out of other systems if you experience access issues.  

What's New:

• We have recently created a Researcher Checklist that outlines all of the suggested steps prior to, during, and following your session. Please have a look, and let us know if we have missed anything!

• Please note that NSF requires us to document how ALC has supported your research. PLEASE help us gather this information by completing a Researcher/Project Form. Note that your information is reported anonymously to NSF and will otherwise remain confidential. 

•  We are also interested in your view of the quality of information and service provided by the ALC. Please complete our Assessment Form (also anonymous). Thanks for your input!

• We are pleased to be able to once again host in-person visits, and have protocols in place to make sessions both safe and effective. We are also able to host virtual sessions, as described in our Covid-19 video. Please contact Mark Pecha (mpecha@arizona.edu) to explore these options. 

• We offered a two-day Short Course on geochronology, petrochronology, and thermochronology at the 2022 National Meeting of the GSA. Check out the modules and recordings of our recent Short Courses from the link to the right. A similar course will be offered at the 2023 GSA Meeting -- please join us!

• We are interested in having you share your experience in conducting geochronologic research! Please chat with Dan Alberts (dalberts@arizona.edu) about recording a short presentation which will be posted on Instagram.

• In an effort to enhance diversity/inclusion in geochronology, we are encouraging researchers to include one extra student from an under-represented minority in their visit to the ALC or during a remote session. We will cover all costs (e.g., travel, lodging, images, and analyses) for this student. Details available from the Analytical Costs link to the right.

• We are pleased to have established a collaboration with Teledyne Technologies that focuses on developing new hardware, software, and applications for U-Th-Pb geochronology and related geochemistry by LA-ICPMS. A new Iridia laser system, equipped with a Cobalt cell and HDIP software, is available for demo visits. Please contact Mark Pecha (mpecha@arizona.edu) and Lucas Smith (Lucas.Smith@teledyne.com) for more information. 

• Please upload your data to Geochron.org!! We have streamlined the process such that it now takes just a couple of minutes per sample. Instructions are available from the Tools=>Geochron Uploading link to the right...

• We are developing new MATLAB-based software tools that can be used for analyzing and visualizing geochronologic and complementary geochemical data. These tools can be accessed from the Analysis Tools links to the right. 

• Check out the growing set of videos on the LaserChron YouTube Channel. Presentations so far focus on methods for preparing/analyzing samples and for maintaining our NU ICPMS, Element2 ICPMS, and Teledyne lasers. 

• We have collected a large batch of FC-1 (Duluth Gabbro) from the original outcrop to serve as a primary or secondary zircon standard for U-Pb geochronology by LA-ICPMS and SIMS. Please contact George Gehrels (ggehrels@arizona.edu) if you would like a bucket! 

• For users of Thermo Element instruments, note that we have developed a routine that extracts information from dat files. This provides access to the raw counts for each measurement, resulting in more reliable data reduction than is possible from FIN2 files. The decoding routine is posted on GitHub, and more information is available in an article available from Archive.org.

• If you are working on an NSF proposal, please contact Mark Pecha (mpecha@arizona.edu) for a letter of support. Information about our instruments and methods should be provided in your "Facilities, Equipment, and Other Resources" section, and is available from the Proposal Tools section (link to right). Financial information can be accessed from the Analytical Costs and Student Support links (to the right). We also have a Data Management Plan that can be modified for your project.

• We continue to develop techniques that integrate U-Th-Pb geochronology, Trace and Rare Earth Element analysis, and Lu-Hf isotope geochemistry. We are able to conduct U-Th-Pb and T/REE analyses just using our Element2 (single-collector ICPMS) -- there is no need for split-stream analysis. U-Th-Pb, T/REE, and Lu-Hf can be done simultaneously in split-stream mode, by connecting the Element2 with our Nu multi-collector ICPMS. But it is much more efficient (and cost-effective) to do the analyses in two different sessions given that most studies require many more U-Pb ages than T/REE or Hf isotope analyses. We accordingly recommend doing large-n U-Th-Pb first (with the E2 or NU), and then selecting optimal grains for T/REE and Hf isotope analyses. 

• We have developed a system for extracting zircons from fine-grained sediments (e.g., loess, siltstone), enabling analysis of zircons down to ~10 microns. The process relies on a series of ultrasonic baths for separating zircon from clay. 

• Our Hitachi 3400N SEM (equipped with Gatan Chroma CL2 color/UV and Oxford EDS/EBSD detectors) is now fully integrated into the LaserChron facility. This instrument generates high-resolution BSE and/or color CL images that are necessary for characterizing grains and optimizing analysis locations. Check our SEM web page at https://sites.google.com/laserchron.org/semlab/?erca=1&authuser=4. Please contact Dr. Zach Michels (zacharymichels@arizona.edu), manager of the SEM lab, for more information.

• Information about ongoing projects, samples, costs, correspondence, etc. can be found at our Current Projects page (link to right). Note that secure sites are available on request.

• Having issues with high Hg content during laser ablation analyses in your lab? You might try installing a gold trap similar to this design. We can provide the glass ends (at no charge) -- contact ggehrels@gmail.com.

• The "Working-Group for Geochronology by LA-ICPMS" (http://www.plasmage.org) continues to be active. Most recent is a paper by Horstwood and others (2016) that presents "best practices" for acquisition, reduction, and reporting of U-Th-Pb data by LA-ICPMS. Workshops and short courses were held at 2018, 2015, 2014, 2013, 2011, and 2009 Goldschmidt/AGU meetings. Note that we are distributing sets of standards to other labs (108 so far) that would like to participate in this interlab calibration -- see Geochronology Standards link to the right.

• We are participating in several efforts to build community and increase access to geochronology. Activities include (1) development of the "It's About Time" whitepaper which was prepared in response to NROES recommendations concerning geochronologic infrastructure, (2) participation in preparation of the Earth In Time report, which recommended that NSF establish a National Geochronology Consortium, (3) helping lead the Geochronology Division of Geological Society of America, and (4) participating in an NSF RCN proposal to establish a "Geochronology Access and Innovation Network."

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