ABSTRACT
Investigations on foraminifers from Upper Pleistocene–Holocene sediments were carried out on twelve cores
from the western Ross Sea continental margin (Drygalski, Joides, North Victoria Land Basins) as part of a
“Progetto Nazionale di Ricerche in Antartide” (P.N.R.A.) multidisciplinary project. Data on the foraminiferal
frequency, species diversity, tests abundance and their state of preservation were presented as a synthesis of
404 core samples to establish their relationships with the main glacial and marine lithofacies of this area. A
total of 126 benthic species, pertaining to 73 genera have been identified; just few taxa, such as Cibicides spp.,
Globocassidulina spp., Trifarina angulosa and Miliammina spp. being the most ubiquitous and in some cases
the dominant species of these paleoenvironments. Two variants of Neogloboquadrina pachyderma, including
thin and thick-shelled forms have been recovered. We propose to use these results to provide the degree of
glacial control during the Last Glacial Maximum and the following Holocene retreat of the ice sheets. High
test fragmentation, low diversity and density tests reflect higher glacial influence of the ice sheet in the
Drygalski Basin, whereas the decreasing percentage of fragmentation and a relative increase of density and
diversity in Drygalski, Joides and North Victoria Land Basins indicate the paleoenvironmental passage from
the ice sheet to the ice shelf condition. The ice shelf retreat is well evidenced in the Joides Basin by a
succession of levels barren of foraminifers alternating with high-density levels, rich in T. angulosa, followed
by a total disappearance of the calcareous foraminifers. Open-marine settings indicative of lower glacial
influence and increased corrosiveness of the water masses is testified by the Miliammina foraminiferal
assemblage during the Holocene in Drygalski and Joides Basins cores. On the contrary, rich and abundant
benthic and planktonic assemblages characterize the Holocene paleoenvironment of the North Victoria Land
area, indicating that the water masses were less corrosive with respect to the other areas. In addition to the
glacial reworking of the tests, and the dissolution due to the corrosive water mass conditions, the
volcaniclastic sediments recovered in the North Victoria Land Basin cores also affected the condition of test
preservation. In volcaniclastic sediments, older than about 20 ka BP, the foraminifers concentration tends to
zero and, when present, their tests are highly damaged or completely broken.
