Fine sand quartz and feldspar (125-250 μm) are the ideal grains for luminescence dating of fluvial, eolian, coastal, and marine sediments. Sampling should focus on sandy layers with little to no mud. Sand-rich facies ensure greater grain exposure on the surface during transport.
Gravity-flow deposits are burdensome to date and sometimes even infeasible. In the absence of sand, fine silt (4-11μm) can also be dated.
Aluminum/steel tubes or opaque PVC pipes are used for sampling. If you decide to use PVC pipes, make sure they are not translucent (look at the tube against a bright light to make sure that there is no light passing through). Both ends of the tubes (~3 cm) are discarded during sample preparation, and only the inner section not exposed to light during sampling will be used for analysis. If the sediment is very cohesive, a block can be collected (15x15x15 cm), and 2-3 cm of each face of the block (that was exposed to light) will be discarded during sample preparation. Again, only the inner section not exposed to light during sampling will be used for analysis.
Tubes/pipes approximate dimensions: diameter of 4 – 7 cm and length of 20 – 30 cm.
Straighten the outcrop or pit wall with a shovel, especially the sampling layer, and insert the tube in it (see image below). Pound the sample tube into the outcrop until you feel/hear a change, indicating the tube is full.
Remove the tube and cover its ends to protect them from light. Try to fill up the tubes to avoid mixing of exposed and unexposed sediments inside after sampling. If you are not able to fully fill the tube with the sampled sediment, you can use packaging peanuts, packaging foam, bubblewrap, or similar to fill it. Close both ends of the tube with Ethylene-vinyl acetate (EVA) caps (or similar) and tape (i.e., insulating tape, silver tape, or masking tape).
Paired samples for environmental radiation dose rate should also be collected. Sample ~300-500 g of sediment in a 30 cm radius of where you inserted the tube, and pack it in a plastic bag. This sample does not need to be protected from light. If this sampling is not possible, we can use a part of the sample inside the tube to measure the radiation dose rate. However, an independent sample is preferable for this purpose, as it makes sample preparation and analysis easier.
IMPORTANT: write down coordinates, elevation (this information can be extracted from Google Earth), and sampling depth. This information is used to determine the cosmic radiation dose rate. If you sample below the water level, write this down (if you’re not sure, take a photo with a scale).
Essentially, you should sample protected from light and with as much sand as possible.