Geoarchaeology of the archaic site Chan-Chan 18, coast of Valdivia: Environmental discrimination of human occupation and its relation with the middle Holocene marine transgression

El sitio arqueológico Chan-Chan 18 (39°30'S/73°15'W) corresponde a un asentamiento costero complejo del Arcaico Medio. En él se reconocen dos fases de ocupación separadas por un hiatus, datadas entre 5.730-6.130 y 6.250-6.420 años cal. AP, respectivamente. Análisis estratigráficos y granulométricos interpretados mediante análisis multivariados, que incluyen muestras actuales de playas y dunas, han permitido reconocer que la ocupación más antigua del sitio se asentó al borde de la berma de una paleoplaya. Tal berma corresponde al registro de la máxima transgresión holocena, y se ubica a una altura de 8 m s.n.m. El registro temporal de la transgresión es sincrónico con otros de la zona centro y norte de Chile, pero reafirma el levantamiento cuaternario generalizado de la costa de Chile centro-sur, tal como lo sugieren otros antecedentes. Este levantamiento ocurre a pesar del hundimiento cosísmico descrito en esta región.In south central Chile the Middle Archaic is well represented by ChanChan 18, a complex coastal settlement located at the coast of Valdivia (39°30'S/73°15'W). In this archaeological site two separated phases of occupation are recognized, the first dated between 5,730 and 6,130, and the second between 6,250 and 6,420 cal. yr BP. Grained size and stratigraphical analyses interpreted by means of multivariate analyses, which include present samples of beaches and dunes, have allowed the recognition that the oldest occupation of the site was located near the berm of a paleo-beach. Such feature corresponds to the record of the maximum Holocene transgression, with an elevation of 8 m a.s.l. The transgression is synchronous with others of north and central Chile, but it confirms the generalized Quaternary rise of the southcentral coast of Chile, as it has been suggested by other observations and studies. This rise happens in spite of the coseismic subsidence described in this region