BYERS PENINSULA, AN EXAMPLE OF THE PALAEOENVIRONMENT FOR CRETACEOUS AND TERTIARY TIMES IN ANTARCTICA

PARICA, C. A.; REMESAL, M.; SALANI, ,F. M.

Buenos Aires

Simposio; XXXI SCAR; 2010

Antactic Cometee

The geological history of Byers Peninsula starts in Jurassic times with deep marinedeposits (Anchorage Formation). The non marine regime took place in the Cretaceous times,near 130 Ma, according to oldest volcanic rocks emplaced in the surface. In those times anon marine basin was developed, ferns rich forests and a strong volcanism marked thefeatures since the Cretaceous to Tertiary. Sedimentary rocks and their structures let tounderstand a seasonal regime, with rainfalls and high energy environment. The carbonatedeposits in lagoons were analyzed by stable isotopes (
18O and
13C). Data from the studiedsamples have values for
13C since -10.6 to -15.9‰ and
18O de 0.5 a -2.8‰. Thesesensitive data confirm the non marine regime for the deposited carbonates, and theequilibrium rank of temperatures was established in between 15 to 20°C. Anyway, somepeperitic breccias (with ammonites remains) in the Ratón Hill suggest the simultaneity inshorts distances of sea water and fresh water in the non marine environment. Theenvironmental frame for the upper Mesozoic and Tertiary is sustained by the palaeoflora,sedimentary features and the stable isotopes analytical data. According to geophysical datathe location of the area was close to the actual one, 62° South Latitude. 6 Antarctic andSouth American climate: linking the past and present record