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Sample Submission & Visitor Information RIGL

Sample Submission

Sample Preparation

  • Mineral separates and bulk rock powders for solution (ID-)MC-ICPMS

Lu-Hf, Sm-Nd geochronology typically requires a total of 800mg of clean garnet fractions and at least 1 gram of whole rock powder. That would provide for 2 whole rock and 4 garnet fractions for each rock sample. 

In specific cases, the required amount of garnet can be more or less than 800mg. Please contact us if your sample falls into one of the following situations: 1) known or suspected low Hf (<0.1ppm) of garnet. 2) large amount of LREE-rich inclusions in garnet; if doing Sm-Nd dating, additional material is needed for leaching. 3) other specific analyses (e.g. micro-sampled garnet zones).   

The garnets should be crushed to fragments of 250-375 µm and handpicked under the binocular microscope to avoid inclusions to the extent possible. Detailed procedures for rock fragmentation and mineral sorting are generally searchable on the internet and are not described here. There are also labs and companies (like Zirchron) offering mineral separation services.

The whole rock powder should be prepared from either a total rock or (preferably) garnet-free rock chips. An agate mortar is preferred for the grinding but almost all methods will be acceptable EXCEPT tungsten-carbide grinding equipment. Avoid this as it makes the sample unusable because of tungsten interferences on hafnium. 

Whole rock power for Sr, Nd, Hf and Pb isotopic analyses should be prepared the same way as that for geochronology analyses except that tungsten-carbide grinding equipment could be used when Hf isotope is not an interest of analysis.  

Please put each fraction in a separate well-labeled vial describing its contents. Glass DRAM vials are recommended as they are made of anti-static materials, but any securely closed vial, even delicately folded weighing paper envelopes, will work fine as long as sample loss is prevented during sample transport.  

  • Solid samples for laser ablation

1 inch diameter epoxy mounts should be cut down to < 1cm tall and have a parallel underside so that the mount can be held properly in the laser ablation stage and the light from underneath can transmit through the epoxy. Standard uncovered thin sections of any thickness, should be no more than 27 mm wide. Carbon or gold coating should be removed from epoxy mounts and thin sections prior to analysis. This can be done by hand scrubbing with Kimwipe + methanol, or by gentle polishing using 1/4 micron diamond paste/spray. Check with a reflected microscope that all carbon/gold has been removed.

The laser is equipped with a high-definition microscope camera capable of resolving features as small as 2 µm that can be viewed using transmitted, reflective and cross polarized light. For internal structures and features that are not recognizable in reflective and transmitted light, users are encouraged to examine the mount or thin section by BSE, CL, and/or x-ray element scans and mark the locations of the potential laser spots on images large enough or can be enlarged to show 20-40 micron spots and surrounding grains.

  • Shipping Address:

1026 Webster Hall
100 Dairy Rd
Pullman WA 99164-2812