"Palinología del Paleogeno tardío-Neo geno temprano, pozo Aries x-l, Plataforma Continental Argentina, Tierra del Fuego"

Susana Palamarckzuk, Viviana Barreda


"ineteen cutting samples from the Aries x-I well, drilled in the Argentine
continental shelf, offshore Tierra del Fuego, were analized for palynology. Marine and terrestrial palynomorph
assemblages, fairly well preserved, though neither diverse nor abundant, were recovered
throughout the studied interval, comprising depths between 240-640 m. Four sections, D, e, B and A from
botton to top are informally proposed on the basis of the palynological content. Sections D through B are
considered Oligocene in age, most probably Upper Oligocene, whereas section A yielded Early Miocene
assemblages, according to previously recorded species distribution in nearby areas. Two marine events
were recognized in sections e and A respectively. The first is characterized by the presence of high
amounts of protoperidinioid dinoflagellate cysts (up to 98%) mostly Brigantedinium sp., and the second,
by equivalent amounts of both major dinocyst groups-gonyaulacoids, protoperidiniods- with absolute
dominance of Nematosphaeropsis rigida Wrenn (32 % of the assemblage). An environmental trend from estuarine-
transitional restricted (section C) to neritic nearshore marine (section A) is suggested. Terrestrial
palynomorphs are abundant in sections e and A. Levels 500-550 m have large amounts of Nothofagidites
spp., pterydophyte spores and fungal rernains, probably reflecting forest vegetation in the surrounding
area. The interva1260-300 m, section A, yielded a diverse pollen grain assemblage mostly composed of the
herbaceous and shrubby families Cyperaceae, Asteraceae, Chenopodiaceae and Anacardiaceae."

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