Micropalaeontological Record of Tsunamis Along the Coast of the Atacama Desert (Northern Chile): A Review

Throughout the Quaternary, repeated tsunamis along the Atacama Desert coast of northern Chile have left distinct sedimentary archives in a variety of coastal environments. This review synthesizes the micropalaeontological evidence reported from seven tsunami deposits previously identified at sites including Bronces, Bahía Inglesa, Carrizal Bajo, Chañaral, Mejillones, Tirúa and Zapatero, spanning from Marine Isotope Stage 7 to the twentieth century. A comparative analysis of these records was undertaken to identify the main micropalaeontological signatures associated with tsunami deposition and to evaluate their occurrence across different depositional settings. The documented assemblages combine marine organisms transported inland by tsunami waves, including benthic foraminifera, ostracods, diatoms, echinoderm remains and siliceous sponge spicules, with freshwater and brackish-water taxa derived from inundated wetlands and lagoons. These mixed assemblages constitute one of the most characteristic micropalaeontological signatures of tsunami deposits along the Atacama coast. The reviewed record also highlights the influence of hyperaridity, tectonic uplift and the limited development of coastal wetlands on both the preservation of tsunami deposits and the composition of their microfossil content. Based on the comparison of the available records, a conceptual framework is proposed that integrates the principal micropalaeontological indicators. This work provides a practical framework for the recognition and interpretation of tsunami deposits in arid coastal regions and may support future palaeotsunami research along the Pacific margin of South America and in comparable coastal environments worldwide.