A Possible Difference in the Surface Relaxivity of Costal and Inland Sands

The 1 H nuclear magnetic resonance (NMR) spin-lattice relaxation rate of hydrated sands is related to the surface-to-volume ratio of the voids or pores between the hydrated sand grains and the surface relaxivity of the grains.The electron spin resonance (ESR) signal is often used to predict the relative surface relaxivity as the surface relaxivity is thought to be proportional to the concentration of paramagnetic species in the sand grains.We have identified a discrepancy in the surface relaxivity and ESR signal of an ocean beach sand compared to two sands of similar diameter from inland deposits.This difference can either be due to more surface weathering of the inland sand or more paramagnetic material from seawater adhering to the ocean sand.