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Finding of a Holocene marine layer in Algarrobo (33°22'S), central Chile. Implications for coastal uplift

2010; National Geology and Mining Service; Volume: 33; Issue: 2 Linguagem: Inglês

10.5027/andgeov33n2-a07

0718-7092

Alfonso Encinas, Francisco Hervé, Rodrigo Villa-Martínez, Sven N. Nielsen, Kenneth L. Finger, Dawn E. Peterson,

Geological formations and processes

A buried Holocene marine bed was discovered upon drilling a water well in Algarrobo (33°22'S), located on the coast of central Chile. Radiocarbon dating of a wood fragment found within the deposit indicates an age of 6450 cal yr BP. The top of this bed, 0.25 m-thick, was reached at an elevation of 3.8 m above mean sea level. This bed contains abundant monospecific faunas of foraminifers (Ammonia tepida) and ostracodes (Cyprideis beaconensis), indicative of deposition in a very shallow, transitional marine environment. Palynologic analysis reveals a Chenopodiaceae-dominated (~70%) assemblage, indicating a relatively arid and warm climate.