García-Escárzaga, A and Clarke, LJ and Gutiérrez-Zugasti, I and González- Morales, MR and Martinez, M and López-Higuera, JM and Cobo, A (2018) Mg/Ca profiles within archaeological mollusc (Patella vulgata) shells: Laser- Induced Breakdown Spectroscopy compared to Inductively Coupled Plasma-

22 Biogenic carbonate mollusc shells have the unique property of being a durable material found 23 in many archaeological and geological sites, recording in their shell chemical composition the 24 ambient environmental conditions during the mollusc’s lifespan. In particular, mollusc shell 25 Mg/Ca ratios have been suggested to be related to seawater temperature, although such a 26 relationship is controversial and appears to be speciesand even location-specific. This study 27 investigates the use of Laser-Induced Breakdown Spectroscopy (LIBS) for the rapid 28