Subfossil avian assemblages and marine invertebrates found within marine deposits help to reconstruct Holocene environmental history at Potter Peninsula

Holocene marine invertebrates and subfossil avian assemblages were
found within marine deposits elevated 1.17-16.7 m a.s.l. on the coasts
of Potter Peninsula, King George Island. Early Holocene Laternula sp
shells in live position were found within mudy sediments deposited in
an open fjord during a sea level high stand, which may reflect the
early Holocene eustatic marine transgression that drowned the south
coast of KGI down to 25-30 m depths. Mid-Holocene penguin and flying
bird remains accompanied by seal bones were discovered within raised
marine beach sediments (2.4-16.7 m), which reflect high relative sea
levels during two mid-Holocene episodes (c. 6400 years BP, and c. 4500
years BP) of seasonally open marine conditions. These episodes may
coincide with a cooling period around Antarctica estimated from
ice-core records between 8000-4000 years BP that preceded the "climate
optimum" in the Antarctic Peninsula (4000-3000 yr BP). Additionally
late Holocene penguin bones were found in abandoned penguin rookeries
located on a raised marine terrace 30-50 m. Paleontological evidence
suggests that these rookeries may have been intermitently active since
2000 years BP, and up to 700 years BP when the site was definitively
abandoned by penguins during a recent climate cooling.