Abstract

The section reviewed is part of the Sealer Hill Member, located in the upper section of the Chester Cone Formation (Crame et al. 1993, redeined by Hathway & Lomas 1998) part of the Byers Group, exposed in the peninsula of the same name in Livingston Island, South Shetland Islands, Antarctica. The studied outcrop is located at the “Zig Zag Gully” as mentioned by Hathway (1997). Consists of mainly volcaniclastic and epiclastic facies of tuffaceous sandstones and agglomerates interbedded with mudstones, deposited rhythmically in a subaqueous environment. Contains marine fossils such as ammonites, bivalves and ish remains, observed between theirst 4 to 5 m from the baseline, along with plant remains, becoming more common towards the top of the sequence. At a palynofacies level, the high content of opaque phytoclasts (inertinite) evidences the wildires associated with intermittent volcanic activity, which would have restricted the development of a gymnosperms forest, being pteridophyte spores dominant. The limited presence of dinolagellate cysts despite the marine environment, is consistent with the high terrigenous input provided by volcanism, generating stressful conditions and low oxygenation, which is coincident with an epiclastic granular subaqueous mass low in the sense of Cas & Wright (1987), deposited in a marine platform environment. In this setting of predominant volcanic activity at high latitudes, the presence of glendonite (pseudomorphs of the low-temperature carbonate mineral ikaite) representing a climate with temperatures to a maximum of 5 to 8° C (DeLurio, 1995), may be due to transient ‘cold snaps‘ or seasonal extremes that resulted from high latitude winter darkness (Littler et al. 2011) during a period of dominantly greenhouse conditions, or be part of a scheme in which global climate conditions were not uniform during the Early Cretaceous.