The Sedimentary Sequences of Hurd Peninsula, Livingston Island, South Shetland Islands: Part of the Late Jurassic — Cretaceous Depositional History of the Antarctic Peninsula

The age of the sedimentary sequences of Hurd Peninsula (here referred to the Miers Bluff Formation (MBF), has been considered so far as Triassic, coeval of the Trinity Group. Recently, a Tithonian ammonite species was found in a non-

in situ

block, coming from the lowermost unexposed part of the Formation. Our micropal-eontological study reveals the occurrence of calcareous nannofossils in six sections. The recorded nannofossil association comprises the following species:

Micula decussata, Calculites obscurus, Arkhangelskiella cymbiformis, Prediscosphaera cretacea, Lucianorhabdus cayeuxii, Cyclagelosphaera reinhardtii, Braarudosphaera bigelowii, Ceratolithoides aculeus, Broinsonia

cf.

parca, Thoracosphaera

sp. indet.,

Nephrolithus

sp. indet.,

Cretarhabdus

sp. indet.,

Watznaueria

sp. indet. It determines a Campanian-Maastrichtian age for the middle and upper part of MBF. Two calcareous nanofossil species,

Prediscosphaera cretacea

and ?

Fasciculithus

sp. indet., found in the Burdick Peak section suggest a Late Maastrichtian to (?) Paleocene age of the uppermost part of the MBF. The sediments of the MBF are possibly coeval of a part of Marambio Group (James Ross Island and Seymour Island) and Williams Point beds (Livingston Island).