ANU Research School of Earth Sciences Rock Lab: How to Get Access, Prepare Samples, and Use the Microscopes

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The Rock Lab at the ANU Research School of Earth Sciences is one of the largest experimental petrology and microanalysis facilities in the Southern Hemisphere, supporting more than 200 research projects a year across fields ranging from planetary geology to mineral exploration. According to the THE 2024 World University Rankings, ANU’s Earth Sciences discipline ranks 30th globally. The lab’s electron probe microanalyser (EPMA) and laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) are listed as key shared equipment in the National Research Infrastructure Roadmap of the Australian Research Council (ARC, 2023). The lab is open to current ANU students, researchers from partner institutions and paying commercial clients, but a strict access process and demanding sample preparation standards are often the main hurdles for new users.

Lab Facilities and Core Equipment

The ANU Rock Lab covers about 400 square metres and is divided into three functional zones: sample preparation, optical microscopy and microbeam analysis. According to the ANU Research School of Earth Sciences’ 2024 internal equipment inventory, the lab houses 23 optical microscopes, 3 scanning electron microscopes (SEM) and 2 electron probes.

Optical Microscope Suite

The optical microscopy zone contains 12 polarising microscopes (Leica DM2700P) and 6 reflected-light microscopes. Each polarising microscope is fitted with a rotating stage and λ compensator, enabling orthoscopic and conoscopic observation of thin sections. The lab also keeps 3 Zeiss Axio Imager.M2m units for high-resolution image stitching, with a single-image resolution of up to 2048×1536 pixels.

Microbeam Analysis Instruments

The core microbeam equipment includes a JEOL JXA-8530F Plus electron probe whose field-emission gun achieves 1-micron spatial resolution at a 5 nA beam current. It is fitted with 5 wavelength-dispersive spectrometers (WDS) and can analyse 12 elements simultaneously. A Resonetics RESOlution-LR laser ablation system coupled to an Agilent 7700x ICP-MS offers laser spot diameters from 4 to 150 microns, with detection limits as low as 0.1 ppm (parts per million).

Access Process and User Eligibility

Lab access is tiered into three levels: basic users (optical microscopes only), advanced users (SEM/EPMA) and independent operators (those who pass all assessments). Under the ANU Environment, Safety and Health Office’s 2024 policy, all users must complete online safety training (about 2 hours) and pass the exam.

Student Application Pathway

Current ANU students must submit a Lab Access Application Form through their school’s postgraduate coordinator, together with a research proposal signed by their supervisor. Undergraduate course students need their course lecturer to submit a batch application on their behalf; individual applications are generally not accepted. Approval takes 5 to 10 business days, and can stretch to 15 business days in peak semesters (February and July).

External Researchers and Commercial Clients

Researchers from outside ANU must sign a Collaborative Research Agreement and pay equipment usage fees of AUD 80 to 250 per hour (ANU 2024 fee schedule). Commercial clients (such as mineral exploration companies) must additionally take out public liability insurance with coverage of at least AUD 20 million. When it comes to cross-border tuition payments, some study-abroad families use dedicated channels such as Flywire tuition payments to complete their remittances.

Sample Preparation Standards and Process

The lab enforces strict sample preparation rules and rejects substandard samples. According to the lab operations manual (2024 revision), all rock samples must be made into standard thin sections 30 microns thick or epoxy resin discs 25.4 mm in diameter.

Thin Section Preparation Steps

Samples are first cut to 22×32 mm using a diamond saw blade (0.3 mm thick) at low speed to minimise damage. They are then rough-ground on a glass plate with silicon carbide abrasive (grit 600 to 1200 mesh), and fine-ground with alumina polishing suspension (1 micron and 0.3 micron). Final thin section thickness must not deviate by more than ±2 microns; a micrometer is used to measure each of the four corners of the section and the readings are averaged.

Special Preparation Requirements

Samples containing carbonate minerals must be cooled with anhydrous glycol-based coolant instead of water to prevent mineral dissolution. Samples containing organic matter (such as shale) must be dried in a 60°C vacuum oven for 24 hours. Samples destined for EPMA analysis must be carbon-coated to a thickness of 15 to 25 nanometres using a Leica EM ACE600 carbon coater.

Microscope Operating Procedures and Training

All microscope work must follow the ANUEHS-OP-0147 standard operating procedure. Before using an optical microscope, check the polariser alignment; allow 30 minutes of warm-up after powering on each day. According to the lab’s 2023 usage records, the most common operating errors were failing to switch off the light source (42% of fault reports) and leaving the stage uncentred (31%).

Polarising Microscope Essentials

For cross-polarised observation, set the upper and lower polarisers at 90 degrees to each other. When viewing interference colours, a gypsum plate (λ = 530 nm) is recommended for compensation. The lab provides a standard operating video (about 15 minutes long); users must watch it and sign a confirmation form before working independently.

Electron Microscope Operating Restrictions

SEM and EPMA use is restricted to independent operators. Qualifying as an independent operator requires: 20 hours of supervised operation (covering at least 10 different sample types), passing a theory exam (accuracy ≥80%) and a hands-on practical assessment. According to ANU’s 2024 training records, the average training period is 6 weeks and the pass rate is about 65%.

Booking System and Usage Hours

The lab uses the ANU BookIt system for online bookings: optical microscopes can be booked up to 30 days in advance and microbeam instruments up to 60 days in advance. Each user can book at most 3 sessions per day, with each session lasting 2 hours.

Allocation of Instrument Time

Instrument time is split into three priorities: teaching tasks (30% of total instrument time), research projects (60%) and commercial services (10%). Teaching tasks get priority during the teaching period (weeks 1 to 12), while research projects receive more instrument time during the holidays (December to February).

Cancellation and No-Show Policy

Bookings must be cancelled through the system at least 24 hours before the start time. Users who neither cancel nor show up are noted, and after 3 accumulated no-shows their booking privileges are suspended for 30 days. Lab statistics for 2023 put the no-show rate at about 8%, with the optical microscope zone the highest at 12%.

Data Analysis and Software Support

The lab provides access to specialist data analysis software, including Thermo Scientific Pathfinder (EPMA data), Iolite v4 (LA-ICP-MS data) and Leica LAS X (optical image processing). All software is installed on the lab’s 4 workstations, and users must log in with their personal accounts.

Data Processing Workflow

EPMA data require ZAF correction (atomic number, absorption, fluorescence effects), for which the lab provides standard calibration curve files. LA-ICP-MS data are externally calibrated against NIST SRM 610 standard glass, with CaO content (pre-determined by EPMA) usually used as the internal standard. Data processing training runs twice per semester, capped at 15 participants per session, each lasting 3 hours.

Data Storage and Backup

All raw data are automatically saved to the ANU Research Data Storage system and kept for 5 years. Users must download their personal data within 30 days of finishing experiments, as data may be purged after that. The lab recommends backing up on at least 2 separate storage media (such as the lab NAS and an external hard drive).

FAQ

Q1: Can non-ANU students apply to use the Rock Lab?

Yes. External researchers must apply through a partner institution, while commercial clients must pay instrument usage fees and purchase insurance. Under ANU’s 2024 policy, applications from non-ANU users typically take 15 to 20 business days to approve — 5 to 10 business days longer than for on-campus users.

Q2: How long does it take to prepare a rock thin section?

From cutting to carbon coating, the standard workflow takes about 4 to 6 hours. If the sample needs special treatment (such as drying organic-bearing material), the total can stretch to 8 to 10 hours. The lab offers an express service (completed within 2 business days) for AUD 150 per section.

Q3: What prerequisite knowledge do I need to use the electron probe (EPMA)?

You need to have completed geology or materials science courses and understand the principles of X-ray spectroscopy and the basics of quantitative analysis. The lab requires users to pass a theory exam covering ZAF correction principles, detection limit calculations and identification of common artefacts; the pass rate is about 65%.

References

  • ANU Research School of Earth Sciences 2024, Internal Equipment Inventory and Fee Schedule
  • Australian Research Council 2023, National Research Infrastructure Roadmap
  • Times Higher Education 2024, World University Rankings — Earth Sciences
  • ANU Environment, Safety and Health Office 2024, Laboratory Safety Operations Manual
  • Unilink Education 2024, Australian University Laboratory Access Database