Late Cretaceous/Paleogene Stratigraphy in the James Ross Basin

REGUERO MA; GOIN FJ; ACOSTA HOSPITALECHE C; DUTRA T; MARENSSI SA

Late Cretaceous/Paleogene West Antarctica Terrestrial Biota and its Intercontinental Affinities

SPRINGER

Lugar: Dordrecht; Año: 2013; p. 19 - 26

Late Cretaceous sedimentary rocks are only exposed around the northernpart of West Antarctica, on the South Shetland Islands and James Ross IslandGroup, Weddell Sea (Fig. 3.1). They were deposited in very different tectonicsettings and environments. The South Shetland Island sequence represents aCenozoic outer-arc (Birkenmajer 1995) or fore-arc (Elliot 1988) succession composed mainly of terrestrial volcanic and sedimentary deposits. It should alsobe noted that some very thin and intermittent sequences of terrestrial sedimentary rocks interbedded within extensive volcanic units on King George Island, South Shetland Islands may be of Maastrichtian age. For example, at Half Three Point, Fildes Peninsula (62°13′40″S; 58°59′01″W), a 4-m-thick sequence oftuffs, tuffaceous sandstones, siltstones and mudstones has yielded an Rb?Sr ageof 71.3 ± 0.3 Ma (Dutra and Batten 2000). On the other hand, the James Rosssequence is made up of marine clastic rocks deposited within a back-arc basin(Elliot 1988; Hathway 2000) and representing the topmost beds of a regressivemega-sequence (Pirrie et al. 1991).