Rv. Dingle et M. Lavelle, Antarctic Peninsula Late Cretaceous-Early Cenozoic palaeoenvironments and Gondwana palaeogeographies, J AFR EARTH, 31(1), 2000, pp. 91-105
A review is made of stratigraphical, geochemical and palaeogeographical dat
a from the northern Antarctic Peninsula and the Southern Ocean for Late Mes
ozoic-Early Cenozoic times. Clay mineral and S/total organic C ratios are u
sed to re-assess earlier scenarios, and it is suggested that eight climatic
episodes affected the northern Antarctic Peninsula between Late Aptian and
Palaeogene times. Evolving palaeogeographies in southern Gondwana allowed
the connection of the inter-continental western Weddell Basin to the proto-
Indian Ocean during Albian to Cenomanian times, and it is suggested that th
is caused an initial cooling of ambient temperatures in the northern Antarc
tic Peninsula area. This situation altered when the South Atlantic seaway w
as opened to equatorial regions, producing a Campanian warm episode. Throug
hout this period, the climate was humid and non-seasonal (ever-wet) and the
adjacent seas were dominated by mineral-walled phytoplankton. A Maastricht
ian to Mid-Palaeocene cool period is postulated following the establishment
of more-polar ocean circulation routes along the southern edge of the Paci
fic Basin, and the climate became seasonally humid with phytoplankton produ
ction switching to organic-walled dominant. The global Palaeogene climatic
optimum was a warm, ever-wet episode but as it waned from Mid-Eocene times,
a further, relatively short, period of marked seasonality is recognised. L
ater, Eocene climates were again ever-wet and became progressively cooler.
The Late Eocene-Early Oligocene opening of the Tasman Sea and Drake Passage
seaways caused cold conditions on Seymour Island, followed rapidly by the
earliest glacial sediments on King George Island and the establishment of m
ineral-walled phytoplankton dominance in the seas. (C) 2000 Elsevier Scienc
e Limited. All rights reserved.