Stable isotope record during the past 1 Myr of ODP Site 162-980 in the subpolar North Atlantic

Benthic foraminiferal carbon isotope records from a suite of drill sites in the North Atlantic are used to trace variations in the relative strengths of Lower North Atlantic Deep Water (LNADW), Upper North Atlantic Deep Water (UNADW), and Southern Ocean Water (SOW) over the past 1 Myr. During glacial intervals, significant increases in intermediate-to-deep delta13C gradients (commonly reaching >1.2?) are consistent with changes in deep water circulation and associated chemical stratification. Bathymetric delta13C gradients covary with benthic foraminiferal delta18O and covary inversely with Vostok CO2, in agreement with chemical stratification as a driver of atmospheric CO2 changes. Three deep circulation indices based on delta13C show a phasing similar to North Atlantic sea surface temperatures, consistent with a Northern Hemisphere control of NADW/SOW variations. However, lags in the precession band indicate that factors other than deep water circulation control ice volume variations at least in this band.

Paleotemperature reconstruction for the past 0.55 Ma of the Subantarctic zone

Estimates of summer sea surface temperatures (SSSTs) derived from planktic foraminiferal associations using the Modern Analog Technique and combined with isotopic analyses and determination of ice-rafted debris, mirror the Pleistocene evolution of the planktic Subantarctic surface waters in the Atlantic Ocean. The SSSTs indicate that the isotherms that define the modern polar front zone and Subantarctic front, were located at more northerly latitudes (up to 7°) during most of the investigated period, which covers the past 550 kyr. Exceptions are during climatic optima in the early Holocene, at marine isotope stages (MIS) 5.5, 7.1, 7.5, 9.3, and presumably during MIS 11.3 when SSSTs exceeded modern values by 1 -5°C. The close similarity between the SSST and the Vostok temperature indicates strong regional temperature correlation. Both records show that MIS 9.3 was the warmest period during the last 420 kyr whereas SSSTs obtained for MIS 11.3 are overestimated due to strong carbonate dissolution. Spectral analysis corroborates that the initiation of warming in southern high latitudes heralds the start of deglaciation on the Northern Hemisphere.

Estimates of %NCW bathing deep North Atlantic (IODP Site 306-U1313) over the past ~3.3 Ma

The circulation and internal structure of the oceans exert a strong influence on Earth's climate because they control latitudinal heat transport and the segregation of carbon between the atmosphere and the abyss (Sigman et al., 2010, doi:10.1038/nature09149). Circulation change, particularly in the Atlantic Ocean, is widely suggested (Bartoli et al., 2005, doi:10.1016/j.epsl.2005.06.020; Haug and Tiedemann, 1998, doi:10.1038/31447; Woodard et al., 2014, doi:10.1126/science.1255586; McKay et al., 2012, doi:10.1073/pnas.1112248109) to have been instrumental in the intensification of Northern Hemisphere glaciation when large ice sheets first developed on North America and Eurasia during the late Pliocene, approximately 2.7 million years ago (Bailey et al., 2013, doi:10.1016/j.quascirev.2013.06.004). Yet the mechanistic link and cause/effect relationship between ocean circulation and glaciation are debated. Here we present new records of North Atlantic Ocean structure using the carbon and neodymium isotopic composition of marine sediments recording deep water for both the Last Glacial to Holocene (35-5 thousand years ago) and the late Pliocene to earliest Pleistocene (3.3-2.4 million years ago). Our data show no secular change. Instead we document major southern-sourced water incursions into the deep North Atlantic during prominent glacials from 2.7 million years ago. Our results suggest that Atlantic circulation acts as a positive feedback rather than as an underlying cause of late Pliocene Northern Hemisphere glaciation. We propose that, once surface Southern Ocean stratification (Sigman, et al., 2004, doi:10.1038/nature02357) and/or extensive sea-ice cover (McKay et al., 2012, doi:10.1073/pnas.1112248109) was established, cold-stage expansions of southern-sourced water such as those documented here enhanced carbon dioxide storage in the deep ocean, helping to increase the amplitude of glacial cycles.

The past, present and future of the Monroe Doctrine,

"Readings" at end of each chapter.

The geographical distribution of animals. With a study of the relations of living and extinct faunas as elucidating the past changes of the earth's surface.

Mode of access: Internet.

some account of the foundation of Eton College and of the past and present condition of the school.

"In the last appendix [are] some sets of examination-papers recently used at the school."

Biographical review of Calhoun County, Michigan : containing historical, biographical and genealogical sketches of many of the prominent citizens of to-day and also of the past.

Includes index.

An introduction to the past and present of the kingdom of Iraq,

Bibliography: p. 112-118.

From the Black Mountain to Waziristan, being an account of the border countries and the more turbulent of the tribes controlled by the North-west frontier province, and of our military relations with them in the past.

Mode of access: Internet.

Old clocks and watches and their makers; being an historical and descriptive account of the different styles of clocks and watches of the past, in England and abroad, to which is added a list of eight thousand makers;

Mode of access: Internet.

The past and the present of St. Andrew's : two discourses preached in St. Andrew's Church, Philadelphia, on the 12th. and 19th. of September, 1958.

Mode of access: Internet.

The Dominion of Canada ; containing a historical sketch of the preliminaries and organization of confederation ; also the vast improvements made ... for the past eighty years under the provincial names. With a large amount of statistical information. /

"Furnished to subscribers only."