Description: The landforms and sediments preserved on the Yermak Plateau (Figs 1–3) provide information on the glacial history and past dynamics of the northwestern-most sector of the Eurasian Ice Sheet (Dowdeswell et al. 2010; Gebhardt et al. 2011), as well as the exchange of ice and water between the North Atlantic and the Arctic Ocean via Fram Strait (Fig. 1a) (Jakobsson et al. 2010). Early ideas about Quaternary ice cover in the Arctic Ocean pro- posed the existence of a circum-Arctic ice shelf prior to the last gla- ciation (e.g. Mercer 1970). More recent work suggested that the major glaciations since the interglacial period of marine oxygen isotope stage (MIS) 5.5 did not extend beyond the Eurasian conti- nental shelf edges. However, geophysical data reveal that ice extended across the Yermak Plateau prior to MIS 5.5 during the particularly extensive glaciation in MIS 6 (Dowdeswell et al. 2010; Jakobsson et al. 2010). By contrast, the presence of a grounding-zone complex beyond NW Spitsbergen (Fig. 3) implies that grounded ice did not extend onto the Yermak Plateau during the Last Glacial Maximum (LGM) (Ottesen & Dowdeswell 2009).

Description: The West Antarctic Ice Sheet (WAIS) and Antarctic Peninsula Ice Sheet (APIS) have exhibited significant changes over recent decades but there is still great uncertainty about how rapidly and how far they will retreat in a warmer climate. For example, it remains unclear whether or not the marine-based WAIS “collapsed” during the last interglacial period, resulting in a global sea-level rise contribution of more than 3 m. Previous studies, including Ocean Drilling Program (ODP) Leg 178, have shown that sediment drifts on the continental rise west of the Antarctic Peninsula contain a rich high-resolution archive of Antarctic margin paleoceanography and APIS history that extends back to at least the Late Miocene. The potential of existing ODP cores from the drifts is, however, compromised by the fact that composite sections are incomplete and lack of precise chronological control. A new drilling proposal (732-Full2) has been scientifically approved and is with the JOIDES Resolution Facilities Board of the International Ocean Discovery Program for scheduling. The main aims of the proposal are to obtain continuous, high-resolution records from sites on sediment drifts off both the Antarctic Peninsula and West Antarctica (southern Bellingshausen Sea) and to achieve good chronological control on them using a range of techniques. We present preliminary results from a recent site survey investigation cruise on RRS James Clark Ross (JR298) that obtained high-resolution multichannel seismic reflection data over the proposed sites and adjacent working areas. The new data provide a basis for interpretation of (i) sedimentary processes that operated during the development of the drifts, and (ii) links between depositional systems on the continental rise, paleo-ice-sheet dynamics and paleoceanographic processes. Through further analyses of seismic and other geophysical data, in combination with marine sediment cores retrieved from the proposed sites, we aim to provide insight into polar margin sediment delivery, Antarctic ice-sheet history and stability, and Antarctic margin paleoceanography. Subsequently, the proposed drilling campaign will allow a detailed chronology to be established on extended records that will provide a basis for high-resolution interpretations extending back through the Pliocene.

Description: Basal hydrological systems play an important role in controlling the dynamic behaviour of ice streams. Data showing their morphology and relationship to geological substrates beneath modern ice streams are, however, sparse and difficult to collect. We present new multibeam bathymetry data that make the Anvers-Hugo Trough west of the Antarctic Peninsula the most completely surveyed palaeo-ice stream pathway in Antarctica. The data reveal a diverse range of landforms, including streamlined features where there was fast flow in the palaeo-ice stream, channels eroded by flow of subglacial water, and compelling evidence of palaeo-ice stream shear margin locations. We interpret landforms as indicating that subglacial water availability played an important role in facilitating ice stream flow and controlling shear margin positions. Water was likely supplied to the ice stream bed episodically as a result of outbursts from a subglacial lake located in the Palmer Deep basin on the inner continental shelf. These interpretations have implications for controls on the onset of fast ice flow, the dynamic behaviour of palaeo-ice streams on the Antarctic continental shelf, and potentially also for behaviour of modern ice streams.

Description: The West Antarctic Ice Sheet (WAIS) and Antarctic Peninsula Ice Sheet (APIS) have exhibited significant changes over recent decades but there is still great uncertainty about how rapidly and how far they will retreat in a warmer climate. For example, it remains unclear whether or not the marine-based WAIS “collapsed” during the last interglacial period, resulting in a global sea-level rise contribution of more than 3 m. Previous studies, including Ocean Drilling Program (ODP) Leg 178, have shown that sediment drifts on the continental rise west of the Antarctic Peninsula contain a rich high-resolution archive of Southern Ocean palaeoceanography and APIS history that extends back to at least the Late Miocene. The potential of existing ODP cores from the drifts is, however, compromised by incomplete composite sections and lack of precise chronological control. A proposal for future drilling on the drifts (732-Full2) has been scientifically approved and is with the JOIDES Resolution Facilities Board for scheduling. The main aims of the proposal are to obtain continuous, high-resolution records from sites on sediment drifts off both the Antarctic Peninsula and West Antarctica (southern Bellingshausen Sea) and to achieve good chronological control on them using a range of techniques. We present preliminary results from a recent site survey investigation cruise on RRS James Clark Ross (JR298) that obtained high-resolution multichannel seismic reflection data, piston cores and box cores to bolster this proposal. The new data and cores provide opportunities to improve understanding of the depositional setting, ensure that there is a comprehensive site survey data package to allay any concerns that the Environmental Protection and Safety Panel may raise, and allow testing of some of the hypotheses underpinning the proposal. The new seismic data provide a basis for interpretation of (i) sedimentary processes that operated during the development of the drifts, and (ii) links between depositional systems on the continental rise, palaeo-ice-sheet dynamics and palaeoceanographic processes. Through further analyses of the seismic and other geophysical data, in combination with the marine sediment cores, we aim to provide insight into polar margin sediment delivery, Antarctic ice-sheet history and stability, and Southern Ocean palaeoceanography. Subsequently, the proposed drilling campaign will allow a detailed chronology to be established on extended records that will provide a basis for high-resolution interpretations extending back through the Pliocene.

Description: Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics, and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic water (AW) that rapidly melts and undercuts Greenland's marine-terminating glaciers. Here we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation approach. A new 150 m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous data sets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals that the total sea level potential of the Greenland ice sheet is 7.42 ± 0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing.

Description: The mapping of submarine glacial landforms is largely dependent on marine geophysical survey methods capable of imaging the seafloor and sub-bottom through the water column. Full global coverage of seafloor mapping, equivalent to that which exists for the Earth's land surface, has, to date, only been achieved by deriving bathymetry from radar altimeters on satellites such as GeoSat and ERS-1 (Smith & Sandwell 1997). The horizontal resolution is limited by the footprint of the satellite sensors and the need to average out local wave and wind effects, resulting in a cell size of about 15 km (Sandwell et al. 2001). A further problem in high latitudes is that the altimeter data are extensively contaminated by the presence of sea ice, which degrades the derived bathymetry (McAdoo & Laxon 1997). Consequently, the satellite altimeter method alone is not suitable for mapping submarine glacial landforms, given that their morphological characterization usually requires a much finer level of detail. Acoustic mapping methods based on marine echo-sounding principles are currently the most widely used techniques for mapping submarine glacial landforms because they are capable of mapping at a much higher resolution.

Description: Glacimarine processes affect about 20% of the global ocean today, and this area expanded considerably under cyclical full-glacial conditions during the Quaternary (Fig. 1) (Dowdeswell et al. 2016b). Many of the submarine landforms produced at the base and margin of past ice sheets remain well preserved on the seafloor in fjords and on high-latitude continental shelves after the retreat of the ice that produced them. These glacial landforms, protected from subaerial erosion and beneath wave-base and tidal currents in water that is often hundreds of metres deep, are gradually buried by both hemipelagic and glacimarine sedimentation; they may be preserved over long periods in the geological record if palaeo-continental shelves are not reworked by subsequent glacier advances or bottom currents (Dowdeswell et al. 2007). This means that, first, submarine glacial landforms can be observed at or close to the modern seafloor after retreat of the last great ice sheets from their most recent Quaternary maximum about 18–20 000 years ago using swath-bathymetric mapping systems and, secondly, buried glacial landforms may also be identified and examined within glacial-sedimentary sequences from Quaternary and earlier ice ages using seismic-reflection methods.

Description: Glacial landforms and sediments exposed sub-aerially have been the subject of description, analysis and interpretation for more than a century (e.g. De Laski 1864; De Geer 1889). Indeed, such features provided important initial observations informing Louis Agassiz's ideas that ice was a key instrument in sculpting the landscape and that glaciers and ice sheets had extended to mid-latitudes during the past, implying that Earth's climate must have changed considerably through time (Agassiz 1840). It is only in the last few decades that attention has begun to focus on the marine evidence for the past growth and decay of ice sheets that is recorded in submarine landforms and sediments preserved on high-latitude continental margins. This interest has been driven, in part, by the recognition that sediments deposited below wave-base are often well preserved in the Quaternary geological record, and may be less subject to erosion and reworking than their terrestrial counterparts. In addition, new marine-geophysical technologies have enabled increasingly high-resolution imaging and penetration of the high-latitude seafloor, most notably using multibeam swath-bathymetric and three-dimensional (3D) seismic-reflection methods, and modern ice-strengthened and ice-breaking research vessels have allowed the effective deployment of these increasingly sophisticated instruments in the often ice-infested waters of the Arctic and Antarctic seas.

Description: Purpose: AZD6244 is a MEK1/2 inhibitor with significant preclinical activity in multiple myeloma cells. This phase II study used a two-stage Simon design to determine the AZD6244 response rate in patients with relapsed or refractory multiple myeloma. Experimental Design: AZD6244 (75 mg) was administered orally, twice a day, continuously for 28-day cycles. Response was evaluated after three cycles. Results: Thirty-six patients received therapy. The median age was 65 years (range: 43–81) and the median number of prior therapies was 5 (range: 2–11). The most common grade 3 and 4 toxicities included anemia, neutropenia, thrombocytopenia, diarrhea, and fatigue. Three deaths occurred possibly related to AZD6244 (2 due to sepsis, 1 due to acute kidney injury). After AZD6244 discontinuation, three additional deaths occurred due to disease progression. The response rate (CR + PR) was 5.6% with a mean duration of response of 4.95 months and median progression-free survival time of 3.52 months. One patient had a very good partial response (VGPR), 1 patient had a partial response, 17 patients had stable disease, 13 patients had progressive disease, and 4 patients could not be assessed for response. Pharmacodynamic studies revealed variable effects on bone marrow CD138 + cell MEK1/2 and ERK1/2 phosphorylation. The best clinical response, a prolonged VGPR, occurred in a patient with an MMSET translocation. Conclusions: Single-agent AZD6244 was tolerable and had minimal activity in this heavily pretreated population. Clin Cancer Res; 22(5); 1067–75. ©2015 AACR .