Livingston Island constains several distinctive sedimentary and volcanic sequences, which document the history and evolution of an important part of the South Shetland Islands magmatic arc. The sedimentary sequence is named the Miers Bluff Formation (MBF) and is interpreted as turbidite since the first geological study on South Shetland Islands. It base and top are not exposed, but a thickness of more than 3000m has been suggested and seems plausible. The turbidite is overlain by Mid-Cretaceous volcanic rocks and intruded by Eocene tonalites. The Miers Bluff Formation and its correlatives, including Trinity Peninsula Group(TPG) in Graham Land, Antarctic Peninsula and Greywacke-Shale Formation (GSF) in South Orkney Islands, display the same lithology and tectonic style, share a common provenance and possibly the same age, but the age is poorly constrained Late Carboniferous-Early Triassic. The pebbly mudstone is common in the TPG, but is scarce in MBF outcrops. In the 1997-1998 year field exploration, four pebbly mudstone layers are distinguished near the Spanish Antarctic Base-“Juan Carles I” Station in Hurd Peninsula, Livingston Island. These layers of pebbly mudstone are massive and no-traction flow structure, and usually over ten meters thick and contain great amount of igneous,sedimentary and metamorphic pebbles. In general, grained size is 4-7 cm, the largest pebble is up to 85 cm, but the bigger pebbles(>50cm) are sparse and are preserved near upper surface in common. Their sorting is bad but their psephicity is well-rounded. These layers of pebbly mudstone are sharply contact with thickened sandstones, they are common in the MBF. The pebbly mudstone is the typical rock of debris flow, may belongs to sediments in the mouth of canyon, the channel of and upper and middle fan of submarine fan and the boundary between the deep sea basin and steep slope. Meanwhile, the depositional environment of MBF is the upper and lower of mid-fan of submarine fan. Hence, the depositonal environment of pebbly mudstone may be the channel of mid fan of submarine fan. MBF has the same tectonic setting, therefore, as the TPG, may be the same history of sedimentary and metamorphism as TPG, too, and Livingston Island contacts with Antarctic Peninsula before the formation of Mesozoic-Cenozoic magmatic arc.
