(Table 1) Age determination of sediment core SO136-003GC

We compile and compare data for the last 150,000 years from four deep-sea cores in the midlatitude zone of the Southern Hemisphere. We recalculate sea surface temperature estimates derived from foraminifera and compare these with estimates derived from alkenones and magnesium/calcium ratios in foraminiferal carbonate and with accompanying sedimentological and pollen records on a common absolute timescale. Using a stack of the highest-resolution records, we find that first-order climate change occurs in concert with changes in insolation in the Northern Hemisphere. Glacier extent and inferred vegetation changes in Australia and New Zealand vary in tandem with sea surface temperatures, signifying close links between oceanic and terrestrial temperature. In the Southern Ocean, rapid temperature change of the order of 6°C occurs within a few centuries and appears to have played an important role in midlatitude climate change. Sea surface temperature changes over longer periods closely match proxy temperature records from Antarctic ice cores. Warm events correlate with Antarctic events A1-A4 and appear to occur just before Dansgaard-Oeschger events 8, 12, 14, and 17 in Greenland.

(Table S1) Chronostratigraphic constrains for sediment core AND1-1B

Thirty years after oxygen isotope records from microfossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth's orbital geometry control the ice ages (Hays et al., 1976, doi:10.1126/science.194.4270.1121), fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles (Raymo and Huybers, 2008, doi:10.1038/nature06589). Furthermore, an understanding of the behaviour of the marine-based West Antarctic ice sheet (WAIS) during the 'warmer-than-present' early-Pliocene epoch (~5-3 Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming (Solomon et al., 2007). Here we present a marine glacial record from the upper 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, ~40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth's axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to ~3° C warmer than today ( Kim and Crowley, 2000, doi:10.1029/1999PA000459) and atmospheric CO2 concentration was as high as ~400 p.p.m.v. (van der Burgh et al., 1993, doi:10.1126/science.260.5115.1788, Raymo et al., 1996, doi:10.1016/0377-8398(95)00048-8). The evidence is consistent with a new ice-sheet/ice-shelf model (Pollard and DeConto, 2009, doi:10.1038/nature07809) that simulates fluctuations in Antarctic ice volume of up to +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting paced by obliquity. During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt (Huybers, 2006, doi:10.1126/science.1125249) under conditions of elevated CO2.

(Table S1) Diatom abundance according to ice cycles in ANDRILL AND1-1B drill core

The influence of Antarctica and the Southern Ocean on Late Pliocene global climate reconstructions has remained ambiguous due to a lack of well-dated Antarctic-proximal, paleoenvironmental records. Here we present ice sheet, sea-surface temperature, and sea ice reconstructions from the ANDRILL AND-1B sediment core recovered from beneath the Ross Ice Shelf. We provide evidence for a major expansion of an ice sheet in the Ross Sea that began at ~3.3 Ma, followed by a coastal sea surface temperature cooling of ~2.5°C, a stepwise expansion of sea ice, and polynya-style deep mixing in the Ross Sea between 3.3 and 2.5 Ma. The intensification of Antarctic cooling resulted in strengthened westerly winds and invigorated ocean circulation. The associated northward migration of Southern Ocean fronts has been linked with reduced Atlantic Meridional Overturning Circulation by restricting surface water connectivity between the ocean basins, with implications for heat transport to the high latitudes of the North Atlantic. While our results do not exclude low-latitude mechanisms as drivers for Pliocene cooling, they indicate an additional role played by southern high-latitude cooling during development of the bipolar world.

(Table 1) Diatom events for AND1-1B, CIROS-2, DVDP-10, and DVDP-11 cores including observed and placed depths

Late Neogene stratigraphy of southern Victoria Land Basin is revealed in coastal and offshore drill cores and a network of seismic data in McMurdo Sound, Antarctica. These data preserve a record of ice sheet response to global climate variability and progressive cooling through the past 5 million years. Application of a composite standard age model for diatom event stratigraphy to the McMurdo Sound drill cores provides an internally precise mechanism to correlate stratigraphic data and derive an event history for the basin. These marine records are indirectly compared to data obtained from geological outcrop in the Transantarctic Mountains to produce an integrated history of Antarctic Ice Sheet response to climate variability from the early Pliocene to Recent. Four distinct chronostratigraphic intervals reflect stages and steps in a transition from a relatively warm early Pliocene Antarctic coastal climate to modern cold polar conditions. Several of these stages and steps correlate with global events identified via geochemical proxy data recovered from deep ocean cores in mid to low latitudes. These correlations allow us to consider linkages between the high southern latitudes and tropical regions and establish a temporal framework to examine leads and lags in the climate system through the late Neogene and Quaternary. The relative influence of climate-tectonic feedbacks is discussed in light of glacial erosion and isostatic rebound that also influence the history along the Southern Victoria Land coastal margin.

Porosity and density of the AND-1B sediment core

A study of density and porosity is presented for the 1285-m-long AND-1B core recovered from a flexural moat in the McMurdo Sound (Antarctica) in order to interpret sediment consolidation in an ice-proximal location on the Antarctic shelf. Various lithologies imply environmental changes from open marine to subglacial, and are numerically expressed in high-resolution whole-core wet-bulk density (WBD). Grain density data interpolated from discrete samples range from 2.14 to 3.85 g/cm3 and are used to calculate porosity from WBD in order to avoid the 5%-15% overestimation and underestimation of porosities obtained by standard methods. The trend of porosity extends from 0.5 near the top (Pleistocene) to 0.2 at the bottom (Miocene). Porosity fluctuations in different lithologies are superimposed with 0.2-0.3 in sequences younger than ca. 1 Ma and 0.5-0.8 in Pliocene diatomites. The AND-1B porosities and void ratios of Pliocene diatomites and Pleistocene mudstones exhibit a large negative offset compared to modern lithological analogs and their consolidation trends. This offset cannot be explained in terms of the effective stress at the AND-1B site. The effective stress ranges from 0 to 4000 kPa in the upper 600 m, and reaches 13,000 kPa at the base of the AND-1B hole. We suggest an excess of effective overburden stress of ~1700 and ~6000 kPa to explain porosities in Pliocene diatomites and Pleistocene mudstones, respectively. This is interpreted as glacial preconsolidation by subsequently grounded ice sheets under subpolar to polar, followed by colder polar types of glaciations. Information on Miocene consolidation is sparse due to alteration by diagenesis.

Petrology and geochemistry of the AND-1B Core

Petrologic descriptions will follow a division related to both grain size and lithology like that adopted in Cape Roberts investigation (Cape Roberts Science Team 2000, hdl:10013/epic.28287.d001, and references therein). First, we describe the petrology of the sand fraction of the core. Second, we report the distribution of clasts with diameter larger than 2 millimeter (mm) and the petrology of basement clasts. Third, we focus on the occurrence and petrology of McMurdo Volcanic Group sediments, which represent the largest component in the core. The final section continues with the compositional characterization of bulk sediments by continuous X-ray fluorescence measurement (XRF scan) integrated by carbonate geochemistry and concludes with the porewater geochemistry. All of these data will contribute to infer palaeoclimatic information and to understand provenance history of detritus, changes in depositional environment, and spatial and temporal evolution of magmatism in McMurdo Ice Shelf area.