Sedimentological and geophysical investigation of sediment cores from the Amundsen Sea

Ice loss from the marine-based, potentially unstable West Antarctic Ice Sheet (WAIS) contributes to current sea-level rise and may raise sea level by up to 3.3 to 5 meters in the future. Over the past few decades, glaciers draining the WAIS into the Amundsen Sea Embayment (ASE) have shown accelerated ice flow, rapid thinning and grounding-line retreat. However, the long-term context of this ice-sheet retreat is poorly constrained, limiting our ability to accurately predict future WAIS behaviour. Here we present a new chronology for WAIS retreat from the inner continental shelf of the eastern ASE based on radiocarbon dates from three marine sediment cores. The ages document a retreat of the grounding line to within ~93 km of its modern position before 11.7±0.7 kyr BP (thousand years before present). This early deglaciation is consistent with ages for grounding-line retreat from the western ASE. Our new data demonstrate that, other than in the Ross Sea, WAIS retreat in the ASE has not continued progressively since the Last Glacial Maximum. Furthermore, our results suggest that the grounding-line position in the ASE was predominantly stable throughout the Holocene, and that any episodes of fast retreat similar to that observed today must have been short-lived. Alternatively, today's rapid retreat was unprecedented during the Holocene. Therefore, the current ice loss must originate in recent changes in regional climate, ocean circulation or ice-sheet dynamics. Incorporation of these results into models is essential to produce robust predictions of future ice-sheet change and its contribution to sea-level rise.

Atlantic 231Pa/230Th and biogenic opal compilation of the Holocene and the LGM

The strength and geometry of the Atlantic meridional overturning circulation is tightly coupled to climate on glacial-interglacial and millennial timescales, but has proved difficult to reconstruct, particularly for the Last Glacial Maximum. Today, the return flow from the northern North Atlantic to lower latitudes associated with the Atlantic meridional overturning circulation reaches down to approximately 4,000 m. In contrast, during the Last Glacial Maximum this return flow is thought to have occurred primarily at shallower depths. Measurements of sedimentary 231Pa/230Th have been used to reconstruct the strength of circulation in the North Atlantic Ocean, but the effects of biogenic silica on 231Pa/230Th-based estimates remain controversial. Here we use measurements of 231Pa/230Th ratios and biogenic silica in Holocene-aged Atlantic sediments and simulations with a two-dimensional scavenging model to demonstrate that the geometry and strength of the Atlantic meridional overturning circulation are the primary controls of 231Pa/230Th ratios in modern Atlantic sediments. For the glacial maximum, a simulation of Atlantic overturning with a shallow, but vigorous circulation and bulk water transport at around 2,000 m depth best matched observed glacial Atlantic 231Pa/230Th values. We estimate that the transport of intermediate water during the Last Glacial Maximum was at least as strong as deep water transport today.

3ème [i.e., Troisième] quatuor : en La mineur, pour instruments à cordes. 1er et 2e violon, alto et violoncelle : oeuvre posthume /

Pl. no. A.C.9809.

1978 Atlantic 3800-meter radioactive waste disposal site survey : sedimentary, micromorphologic and geophysical analyses /

"Prepared June 1979."

Proposed small saver deposit instruments [microform] : hearing before the Subcommittee on Financial Institutions Supervision, Regulation and Insurance of the Committee on Banking, Finance and Urban Affairs, House of Representatives, Ninety-sixth Congress, first session, May 7, 1979.

Reuse of record except for individual research requires license from Congressional Information Service, Inc.

Integrated use of surface-geophysical methods to indicate subsurface fractures at Milford, New Hampshire /

Includes bibliographical references (p. 36-38).

Catalogue des instruments de musique anciens et modernes.

Absorbed by the William Heyer collection in Cologne about 1906.

Italian inventions for instruments with a keyboard /

At head of title: Paper read before the fourth congress of the International Musical Society (Internationale Musikgesellschaft), London: May 29 to June 3, 1911.

Occupational employment survey booklet of definitions : instruments and related industries.

"Approval expires: 3-31-93."

Picture book of musical instruments /

Includes index.

A manual of the principal instruments used in American engineering and surveying /

Cover title: Gurley's manual: American engineers' and surveyors' instruments.

A manual of the principal instruments used in American engineering and surveying /

Cover title: Gurley's Manual. American engineers' and surveyors' instruments.

The Star collection of instrumental music; arranged for wind and string instruments, and for the use of small bands and orchestras.

Contains arrangements of songs, selections from operas, dances, etc.