Crustal Geophysics and Geochemistry Science Center

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PetLab - Sample Preparation

Physical property measurements can be made on rocks, unconsolidated sediments and liquids. It is important not to alter a rock's properties during sample preparation. For poorly consolidated samples, care should be taken not to disturb the samples sediment. If samples need to be cut or cored, it is important to use water only as a coolant and to minimize the rock's exposure to the coolant.

Some physical properties, such as density and electrical resistivity, can vary significantly as a function of water content. To observe a samples physical properties as a function of water content, samples are typically measured at 4 different hydration states including; 1) "as received", 2) oven dry, 3) hydrated at 100% relative humidity, and 4) saturated. If samples are properly preserved, they contain their original water content and the "as received" measurements can provide property information for a sample in its natural setting. Oven dry measurements provide property data on the samples bulk matrix without the presence of water. Hydrated measurements provide data consistent with samples exposed to atmospheric or vadose zone moisture, whereas saturated measurements provide data consistent with below water table conditions. The oven dry and saturated measurements represent hydration state end members that define the range of physical properties to be expected for a given sample.

If there are additional questions regarding sample preparation and preservation, please contact us.

Mineral Resources Program
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