Low field nuclear magnetic resonance as a potential tool for differentiating bedded and nodular cherts outcrops
Description
This data compiles 1- and 2-D LF-NMR relaxation data of nodular and bedded cherts. Measurements were conducted on nine rock cores derived from three distinct outcrops situated in the southern KCU region. Specifically, samples were obtained from Sowiniec Horst (SB1), Ujazd (SA9, SA9!a, SA9!b, SA3, SA8), and Wielkanoc Quarry (SC1, SC2, SC4b). The measurement protocol involved assessing each sample in three water saturation states: native, dried (after 12 hours at 200°C), and saturated (after 24 hours in a vacuum at room temperature). To prevent evaporation of absorbed water, saturated samples were safeguarded with a residual amount of plastic foil (0.06 g). Furthermore, differential state (SD) distributions were obtained by subtracting raw dry sample distributions from raw saturated sample distributions. This approach specifically characterized movable water, providing insights into open porosity.
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Steps to reproduce
1D-T1, 1D-T2 and T1-T2 NMR experiments were carried out for samples in native (N), dry (D), saturated (S) and differential (SD) saturation states on a 2 MHz Magritek Rock Core Analyzer (Aachen, Germany) applying Inversion Recovery (IR), Carr−Purcell−Meiboom−Gill (CPMG) and combined IR-CPMG sequences, respectively. Experimental parameters were: - For the 1D-T1 experiment: TR (inter-experiment time) of 5000 ms, a Min-Max delay of 0,05-5000 ms, 24 scans, 30 steps, and an α (smoothing factor) of 1. - For the 1D-T2 experiment: TR of 1500 ms, TE of 60 µs, 10000 echoes, and 512 scans, with the α of 0,6. - For the T1-T2 experiment: TR of 1500 ms, TE of 60 µs, 10000 echoes, Min-Max delay of 0,05-5000 ms, τmin-τmax of 0.1-5000 ms, 64 scans, 30 steps, and an α of 1.