@article {2620,
	title = {Deglacial floods in the Beaufort Sea preceded Younger Dryas cooling},
	journal = {Nature Geoscience},
	volume = {11},
	year = {2018},
	month = {08/2018},
	pages = {599 - 604},
	abstract = {A period of cooling about 13,000 years ago interrupted about 2,000 years of deglacial warming. Known as the Younger Dryas (YD), the event is thought to have resulted from a slowdown of the Atlantic meridional overturning circulation in response to a sudden flood of Laurentide Ice Sheet meltwater that reached the Nordic Seas. Oxygen isotope evidence for a local source of meltwater to the open western North Atlantic from the Gulf of St Lawrence has been lacking. Here we report that the eastern Beaufort Sea contains the long-sought signal of O-18-depleted water. Beginning at similar to 12.94 {\textpm} 0.15 thousand years ago, oxygen isotopes in the planktonic foraminifera from two sediment cores as well as sediment and seismic data indicate a flood of meltwater, ice and sediment to the Arctic via the Mackenzie River that lasted about 700 years. The minimum in the oxygen isotope ratios lasted similar to 130 years. We suggest that the floodwater travelled north along the Canadian Archipelago and then through the Fram Strait to the Nordic Seas, where freshening and freezing near sites of deep-water formation would have suppressed convection and caused the YD cooling by reducing the meridional overturning.},
	issn = {1752-0894},
	doi = {10.1038/s41561-018-0169-6},
	url = {http://www.nature.com/articles/s41561-018-0169-6http://www.nature.com/articles/s41561-018-0169-6.pdfhttp://www.nature.com/articles/s41561-018-0169-6http://www.nature.com/articles/s41561-018-0169-6.pdf},
	author = {Keigwin, L. D. and Klotsko, S. and Zhao, N. and Reilly, B. and Giosan, L. and Driscoll, N. W.}
}
@article {28,
	title = {Comparison of large and ultra-small delta c-14 measurements in core top benthic foraminifera from the Okhotsk Sea},
	journal = {Radiocarbon},
	volume = {57},
	year = {2015},
	note = {PT: J; TC: 1; UT: WOS:000351052600010},
	pages = {123-128},
	abstract = {The radiocarbon activity of benthic foraminifera was investigated in surface sediments from a high deposition rate location at a depth of 1000 m in the Okhotsk Sea. Sediments were preserved and stained with Rose Bengal to identify foraminifera that contain cytoplasm. The benthic fauna at this site is dominated by large specimens of Uvigerina peregrina, and bulk samples (similar to 150 individuals) of stained and unstained specimens were dated. The stained sample was about 240 C-14 yr younger than the unstained, and the presence of bomb C-14 is inferred by comparison to water column data in the nearby open North Pacific. Using new methods, multiple measurements were also made on samples of three stained and unstained individuals (as small as 7 mu g C). Results are consistent with those from the bulk samples. This suggests that similar ultra-small measurements could be made at other locations to reveal the age distribution of individuals in a sediment sample in order to assess the extent of bioturbation and the presence of bomb C-14 contamination.},
	issn = {0033-8222},
	doi = {10.2458/azu_rc.57.18153},
	author = {Keigwin, L. D. and Gagnon, A. R.}
}
@article {27,
	title = {Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean},
	journal = {Earth and Planetary Science Letters},
	volume = {425},
	year = {2015},
	pages = {93-104},
	abstract = {We investigate the radiocarbon ventilation age in deep equatorial Pacific sediment cores using the difference in conventional 14C age between coexisting benthic and planktonic foraminifera, and integrate those results with similar data from around the North Pacific Ocean in a reconstruction for the last glaciation (15 to 25 conventional 14C ka). Most new data from both the Equatorial Pacific and the Emperor Seamounts in the northwestern Pacific come from maxima in abundance of benthic taxa because this strategy reduces the effect of bioturbation. Although there remains considerable scatter in the ventilation age estimates, on average, ventilation ages in the Equatorial Pacific were significantly greater below 3.2 km ( \~{} 3080 {\textpm} 1125 yrs , n = 15 ) than in the depth interval 1.9 to 3.0 km ( \~{} 1610 {\textpm} 250 yrs , n = 12 ). When compared to the average modern seawater Δ C 14 profile for the North Pacific, the Equatorial Pacific glacial data suggest an abyssal front located somewhere between 3.0 and 3.2 km modern water depth. Above that depth, the data may indicate slightly better ventilation than today, and below that depth, glacial Equatorial Pacific data appear to be as old as last glacial maximum (LGM) deep water ages reported for the deep southern Atlantic. This suggests that a glacial reservoir of aged waters extended throughout the circumpolar Southern Ocean and into the Equatorial Pacific. Renewed ventilation of such a large volume of aged (and, by corollary, carbon-rich) water would help to account for the rise in atmospheric pCO2 and the fall in Δ C 14 as the glaciation drew to a close.},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2015.05.025},
	url = {http://www.sciencedirect.com/science/article/pii/S0012821X15003210},
	author = {Keigwin, L. D. and Lehman, S. J.}
}
@article {2550,
	title = {Synchronous Deglacial Overturning and Water Mass Source Changes},
	journal = {Science},
	volume = {327},
	year = {2010},
	month = {Jan-01-2010},
	pages = {75 - 78},
	abstract = {Understanding changes in ocean circulation during the last deglaciation is crucial to unraveling the dynamics of glacial-interglacial and millennial climate shifts. We used neodymium isotope measurements on postdepositional iron-manganese oxide coatings precipitated on planktonic foraminifera to reconstruct changes in the bottom water source of the deep western North Atlantic at the Bermuda Rise. Comparison of our deep water source record with overturning strength proxies shows that both the deep water mass source and the overturning rate shifted rapidly and synchronously during the last deglacial transition. In contrast, any freshwater perturbation caused by Heinrich event 1 could have only affected shallow overturning. These findings show how changes in upper-ocean overturning associated with millennial-scale events differ from those associated with whole-ocean deglacial climate events.},
	issn = {0036-8075},
	doi = {10.1126/science.1178068},
	url = {http://www.sciencemag.org/cgi/doi/10.1126/science.1178068},
	author = {Roberts, N. L. and Piotrowski, A. M. and McManus, J. F. and Keigwin, L. D.}
}
@article {256,
	title = {Bioturbation artifacts in zero-age sediments},
	journal = {Paleoceanography},
	volume = {24},
	year = {2009},
	note = {id: 1826; 535DQ Times Cited:0 Cited References Count:18; YY},
	abstract = {Most seafloor sediments are dated with radiocarbon, and the sediment is assumed to be zero-age (modern) when the signal of atmospheric testing of nuclear weapons is present (Fraction modern (Fm) > 1). Using a simple mass balance, we show that even with Fm > 1, half of the planktonic foraminifera at the seafloor can be centuries old, because of bioturbation. This calculation, and data from four core sites in the western North Atlantic indicate that, first, during some part of the Little Ice Age (LIA) there may have been more Antarctic Bottom Water than today in the deep western North Atlantic. Alternatively, bioturbation may have introduced much older benthic foraminifera into surface sediments. Second, paleo-based warming of Sargasso Sea surface waters since the LIA must lag the actual warming because of bioturbation of older and colder foraminifera.},
	issn = {0883-8305},
	doi = {10.1029/2008pa001727},
	author = {Keigwin, L. D. and Guilderson, T. P.}
}
@article {1843,
	title = {Interpreting Nd isotope and Pa-231/Th-230 records in the deep Western North Atlantic},
	journal = {Geochimica Et Cosmochimica Acta},
	volume = {73},
	year = {2009},
	note = {Suppl. S460ys
Times Cited:0
Cited References Count:3
},
	month = {Jun},
	pages = {A1107-A1107},
	keywords = {circulation},
	isbn = {0016-7037},
	doi = {10.1016/j.gca.2009.05.014},
	author = {Roberts, N. L. and Piotrowski, A. M. and McManus, J. F. and Keigwin, L. D.}
}
@article {318,
	title = {Subtropical Atlantic salinity variability and Atlantic meridional circulation during the last deglaciation},
	journal = {Geology},
	volume = {36},
	year = {2008},
	note = {id: 862; ISI Document Delivery No.: 381WN Times Cited: 5 Cited Reference Count: 32 Cited References: *CLIMAP PROJ MEMB, 1981, GEOL SOC AM MAP CHAR ANAND P, 2003, PALEOCEANOGRAPHY, V18, ARTN 1050 BENWAY HM, 2006, PALEOCEANOGRAPHY, V21, ARTN PA3008 BEVINGTON P, 2002, DATA REDUCTION ERROR BOYLE EA, 1987, NATURE, V330, P35 BROECKER WS, 1990, PALEOCEANOGRAPHY, V5, P469 CARLSON AE, 2007, P NATL ACAD SCI USA, V104, P6556, DOI 10.1073/pnas.0611313104 CLARK PU, 2004, SCIENCE, V304, P1141 GRIMM EC, 2006, QUATERNARY SCI REV, V25, P2197, DOI 10.1016/j.quascirev.2006.04.008 GROOTES PM, 1993, NATURE, V366, P552 KASPI Y, 2004, PALEOCEANOGRAPHY, V19, ARTN PA3004 KNORR G, 2003, NATURE, V424, P532, DOI 10.1038/nature01855 LEA DW, 2003, SCIENCE, V301, P1361 LEDUC G, 2007, NATURE, V445, P908, DOI 10.1038/nature05578 LEGRANDE AN, 2006, GEOPHYS RES LETT, V33, ARTN L12604 LEGRANDE AN, 2008, PALEOCEANOGRAPHY, V23, DOI 10.1029/2008PA001610 MCMANUS JF, 2004, NATURE, V428, P834, DOI 10.1038/nature02494 OPPO DW, 2007, GEOPHYS RES LETT, V34, ARTN L13701 PEETERS FJC, 2004, NATURE, V430, P661, DOI 10.1038/nature02785 PETERSON LC, 2000, SCIENCE, V290, P1947 ROBINSON LF, 2005, SCIENCE, V310, P1469, DOI 10.1126/science.1114832 RUHLEMANN C, 1999, NATURE, V402, P511 SCHMIDT GA, 2007, J GEOPHYS RES-ATMOS, V112, ARTN D10103 SCHMIDT MW, 2004, NATURE, V428, P160, DOI 10.1038/nature02346 SCHMIDT MW, 2006, NATURE, V443, P561, DOI 10.1038/nature05121 SCHMITZ WJ, 1995, REV GEOPHYS, V33, P151 SKINNER LC, 2006, QUATERNARY SCI REV, V25, P3312, DOI 10.1016/j.quascirev.2006.07.005 STOUFFER RJ, 2006, J CLIMATE, V19, P1365 THOMAS AL, 2006, EARTH PLANET SC LETT, V241, P493, DOI 10.1016/j.epsl.2005.11.031 WANG XF, 2004, NATURE, V432, P740, DOI 10.1038/nature03067 WEAVER AJ, 2003, SCIENCE, V299, P1709 WELDEAB S, 2006, EARTH PLANET SC LETT, V241, P699, DOI 10.1016/j.epsl.2005.11.012 Carlson, Anders E. Oppo, Delia W. Came, Rosemarie E. LeGrande, Allegra N. Keigwin, Lloyd D. Curry, William B. Geological soc amer, inc Boulder; YY},
	pages = {991-994},
	abstract = {During the last deglaciation (ca. 21-10 ka), freshening of the North Atlantic surface likely caused reductions in Atlantic meridional overturning circulation (AMOC); the mechanisms related to AMOC recovery remain poorly understood. Here we present three new deglacial surface temperature and delta O-18(seawater) (delta O-18(sw)) reconstructions from the western subtropical North and South Atlantic. Similarities to tropical Caribbean and western Atlantic delta O-18(sw) records suggest that a salty surface water mass accumulated in the western Atlantic from 27 degrees S to 33 degrees N during periods of reduced AMOC. However, delta O-18(sw) decreases led deep AMOC resumption by hundreds of years. We suggest that the northward export of salt previously trapped in the western Atlantic resulted in the early establishment of a shallow overturning circulation that eventually culminated in deep AMOC resumption, implying that AMOC may constitute a self-limiting system.},
	issn = {0091-7613},
	doi = {10.1130/g25080a.1},
	author = {Carlson, A. E. and Oppo, D. W. and Came, R. E. and LeGrande, A. N. and Keigwin, L. D. and Curry, W. B.}
}
@article {1941,
	title = {Flooding of Bering Strait and Holocene climate in the Chukchi Sea},
	journal = {Geology},
	volume = {34},
	year = {2006},
	note = {id: 678},
	month = {2006},
	pages = {861-864},
	author = {Keigwin, L. D. and Donnelly, J. P. and Cook, M. S. and Driscoll, N. W. and Brigham-Grette, J.}
}
@article {678,
	title = {Rapid sea-level rise and Holocene climate in the Chukchi Sea},
	journal = {Geology},
	volume = {34},
	year = {2006},
	note = {089zkTimes Cited:67Cited References Count:18},
	month = {Oct},
	pages = {861-864},
	abstract = {Three new sediment cores from the Chukchi Sea preserve a record of local paleoenvironment, sedimentation, and flooding of the Chukchi Shelf (similar to-50 m) by glacial-eustatic sea-level rise. Radiocarbon dates on foraminifera provide the first marine evidence that the sea invaded Hope Valley (southern Chukchi Sea, -53 m) as early as 12 ka. The lack of significant sediment accumulation since ca. 7 ka in Hope Valley, southeastern Chukchi Shelf, is consistent with decreased sediment supply and fluvial discharge to the shelf as deglaciation of Alaska concluded. Abundant benthic foraminifera from a site west of Barrow Canyon indicate that surface waters were more productive 4-6 ka, and this productivity varied on centennial time scales. An offshore companion to this core contains a 20 m record of the Holocene. These results show that carefully selected core sites from the western Arctic Ocean can have a temporal resolution equal to the best cores from other regions, and that these sites can be exploited for high-resolution studies of the paleoenvironment.},
	issn = {0091-7613},
	doi = {10.1130/G22712.1},
	author = {Keigwin, L. D. and Donnelly, J. P. and Cook, M. S. and Driscoll, N. W. and Brigham-Grette, J.}
}
@article {1988,
	title = {The 8200 year B. P. event in the slop water system, western sublpolar North Atlantic},
	journal = {Paleoceanography},
	volume = {20},
	year = {2005},
	note = {id: 1097},
	month = {2005},
	author = {Keigwin, L. D. and Sachs, J. P. and Rosenthal, Y. and Boyle, E. A.}
}
@article {600,
	title = {The deglacial history of surface and intermediate water of the Bering Sea},
	journal = {Deep-Sea Research Part Ii-Topical Studies in Oceanography},
	volume = {52},
	year = {2005},
	note = {995ksTimes Cited:51Cited References Count:52},
	pages = {2163-2173},
	abstract = {The lithology of deglacial sediments from the Bering Sea includes intervals of laminated or dysaerobic sediments. These intervals are contemporaneous with the occurrence of laminated sediments from the California margin and Gulf of California, which suggests widespread low-oxygen conditions at intermediate depths in the North Pacific Ocean. The cause could be reduced intermediate water ventilation, increased organic carbon flux, or a combination of the two. We infer abrupt decreases of planktonic foraminifer delta(18)O at 14,400 and 11,650 yr BP, which may be a combination of both freshening and warming. On the Shirshov Ridge, the abundance of sea-ice diatoms of the genus Nitzschia reach local maxima twice during the deglaciation, the latter of which may be an expression of the Younger Dryas. These findings expand the extent of the expression of deglacial millennial-scale climate events to include the northernmost Pacific. (c) 2005 Elsevier Ltd. All rights reserved.},
	issn = {0967-0645},
	doi = {10.1016/j.dsr2.2005.07.004},
	author = {Cook, M. S. and Keigwin, L. D. and Sancetta, C. A.}
}
@article {694,
	title = {Radiocarbon variability in the western North Atlantic during the last deglaciation},
	journal = {Science},
	volume = {310},
	year = {2005},
	note = {Robinson, Laura FAdkins, Jess FKeigwin, Lloyd DSouthon, JohnFernandez, Diego PWang, S-LScheirer, Daniel SengResearch Support, Non-U.S. Gov{\textquoteright}tResearch Support, U.S. Gov{\textquoteright}t, Non-P.H.S.2005/12/03 09:00Science. 2005 Dec 2;310(5753):1469-73. Epub 2005 Nov 3.},
	month = {Dec 02},
	pages = {1469-73},
	abstract = {We present a detailed history of glacial to Holocene radiocarbon in the deep western North Atlantic from deep-sea corals and paired benthic-planktonic foraminifera. The deglaciation is marked by switches between radiocarbon-enriched and -depleted waters, leading to large radiocarbon gradients in the water column. These changes played an important role in modulating atmospheric radiocarbon. The deep-ocean record supports the notion of a bipolar seesaw with increased Northern-source deep-water formation linked to Northern Hemisphere warming and the reverse. In contrast, the more frequent radiocarbon variations in the intermediate/deep ocean are associated with roughly synchronous changes at the poles.},
	issn = {0036-8075 (Linking)},
	doi = {10.1126/science.1114832},
	author = {Robinson, L. F. and Adkins, J. F. and Keigwin, L. D. and Southon, J. and Fernandez, D. P. and Wang, S. L. and Scheirer, D. S.}
}
@article {629,
	title = {Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes},
	journal = {Nature},
	volume = {428},
	year = {2004},
	note = {McManus, J FFrancois, RGherardi, J-MKeigwin, L DBrown-Leger, SengResearch Support, Non-U.S. Gov{\textquoteright}tResearch Support, U.S. Gov{\textquoteright}t, Non-P.H.S.England2004/04/23 05:00Nature. 2004 Apr 22;428(6985):834-7.},
	month = {Apr 22},
	pages = {834-7},
	abstract = {The Atlantic meridional overturning circulation is widely believed to affect climate. Changes in ocean circulation have been inferred from records of the deep water chemical composition derived from sedimentary nutrient proxies, but their impact on climate is difficult to assess because such reconstructions provide insufficient constraints on the rate of overturning. Here we report measurements of 231Pa/230Th, a kinematic proxy for the meridional overturning circulation, in a sediment core from the subtropical North Atlantic Ocean. We find that the meridional overturning was nearly, or completely, eliminated during the coldest deglacial interval in the North Atlantic region, beginning with the catastrophic iceberg discharge Heinrich event H1, 17,500 yr ago, and declined sharply but briefly into the Younger Dryas cold event, about 12,700 yr ago. Following these cold events, the 231Pa/230Th record indicates that rapid accelerations of the meridional overturning circulation were concurrent with the two strongest regional warming events during deglaciation. These results confirm the significance of variations in the rate of the Atlantic meridional overturning circulation for abrupt climate changes.},
	issn = {0028-0836 (Linking)},
	doi = {10.1038/nature02494},
	author = {McManus, J. F. and Francois, R. and Gherardi, J. M. and Keigwin, L. D. and Brown-Leger, S.}
}
@article {2044,
	title = {Radiocarbon and stable isotope constraints on Last Glacial Maximum and Younger Dryas ventilation in the western North Atlantic},
	journal = {Paleoceanography},
	volume = {19},
	year = {2004},
	note = {870dfTimes Cited:72
Cited References Count:60
},
	month = {Nov 3},
	abstract = {[1] Foraminiferal abundance, C-14 ventilation ages, and stable isotope ratios in cores from high deposition rate locations in the western subtropical North Atlantic are used to infer changes in ocean and climate during the Younger Dryas (YD) and Last Glacial Maximum (LGM). The delta(18)O of the surface dwelling planktonic foram Globigerinoides ruber records the present-day decrease in surface temperature (SST) of similar to 4 degreesC from Gulf Stream waters to the northeastern Bermuda Rise. If during the LGM the modern delta(18)O/salinity relationship was maintained, this SST contrast was reduced to 2 degreesC. With LGM to interglacial delta(18)O changes of at least 2.2parts per thousand, SSTs in the western subtropical gyre may have been as much as 5 degreesC colder. Above similar to 2.3 km, glacial delta(13)C was higher than today, consistent with nutrient-depleted ( younger) bottom waters, as identified previously. Below that, delta(13)C decreased continually to - 0.5parts per thousand, about equal to the lowest LGM delta(13)C in the North Pacific Ocean. Seven pairs of benthic and planktonic foraminiferal C-14 dates from cores > 2.5 km deep differ by 1100 +/- 340 years, with a maximum apparent ventilation age of similar to 1500 years at 4250 m and at similar to 4700 m. Apparent ventilation ages are presently unavailable for the LGM < 2.5 km because of problems with reworking on the continental slope when sea level was low. Because LGM \&delta;C-13 is about the same in the deep North Atlantic and the deep North Pacific, and because the oldest apparent ventilation ages in the LGM North Atlantic are the same as the North Pacific today, it is possible that the same water mass, probably of southern origin, flowed deep within each basin during the LGM. Very early in the YD, dated here at 11.25 +/- 0.25 ( n = 10) conventional C-14 kyr BP ( equal to 12.9 calendar kyr BP), apparent ventilation ages < 2.3 km water depth were about the same as North Atlantic Deep Water today. Below similar to 2.3 km, four YD pairs average 1030 +/- 400 years. The oldest apparent ventilation age for the YD is 1600 years at 4250 m. This strong contrast in ventilation, which indicates a front between water masses of very different origin, is similar to glacial profiles of nutrient-like proxies. This suggests that the LGM and YD modes of ocean circulation were the same.},
	keywords = {benthic foraminifera, deep-sea sediments, ice-age, Ocean circulation, ocean ventilation, pacific-ocean, radiocarbon, SARGASSO SEA, southern-ocean, Thermohaline circulation, united-states, water circulation, western north atlantic},
	isbn = {0883-8305},
	doi = {10.1029/2004PA001029},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&amp;SrcAuth=Alerting\&amp;SrcApp=Alerting\&amp;DestApp=WOS\&amp;DestLinkType=FullRecord;UT=WOS:000225033500003},
	author = {Keigwin, L. D.}
}
@article {617,
	title = {A 1600-year history of the Labrador Current off Nova Scotia},
	journal = {Climate Dynamics},
	volume = {21},
	year = {2003},
	note = {698thTimes Cited:25Cited References Count:31},
	month = {Jul},
	pages = {53-62},
	abstract = {A multicore from Emerald Basin, on the continental margin off Nova Scotia, has a modern C-14 age at the top, and other C-14 dates indicate a linear sedimentation rate of similar to30 cm/ka to 1600 calendar years BP. This rate is great enough to record century-to-millennial scale changes in the surface and deep (similar to250 m) waters in the basin that are influenced by the Labrador Current. We applied five proxies for seawater temperature changes to the sediments of Emerald Basin, including the percent abundance and the oxygen isotope ratio (delta(18)O) of the polar planktonic foraminifer N. pachyderma (s.), the unsaturation ratio of alkenones (U-37(k{\textquoteright})) produced by prymnesiophyte phytoplankton, and the delta(18)O and Mg/Ca of benthic foraminifera. All five proxies indicate the ocean warmed suddenly sometime in the past 150 years or so. The exact timing of this event is uncertain because C-14 dating is inaccurate in recent centuries, but this abrupt warming probably correlates with widespread evidence for warming in the Arctic in the nineteenth century. Because the Canadian Archipelago is one of the two main sources for the Labrador Current, warming and melting of ice caps in that region may have affected Labrador Current properties. Before this recent warming, sea surface temperature was continually lower by 1-2 degreesC, and bottom water was colder by about 6 degreesC in Emerald Basin. These results suggest that there was no Medieval Warm Period in the coastal waters off Nova Scotia. Because there is also no evidence of medieval warming in the Canadian archipelago, it seems likely that coastal waters from Baffin Bay to at least as far south as Nova Scotia were continually cold for similar to1500 of the past 1600 years.},
	issn = {0930-7575},
	doi = {10.1007/s00382-003-0316-6},
	author = {Keigwin, L. D. and Sachs, J. P. and Rosenthal, Y.}
}
@article {793,
	title = {Late Pleistocene-Holocene paleoceanography and ventilation of the Gulf of California},
	journal = {Journal of Oceanography},
	volume = {58},
	year = {2002},
	note = {554heTimes Cited:53Cited References Count:48},
	month = {Apr},
	pages = {421-432},
	abstract = {Sediment cores collected in 1990 from the Gulf of California have been studied using stable isotope and radiocarbon techniques to reconstruct the climate and ventilation histories since the last glacial maximum. Benthic foraminiferal delta(18)O from core tops in a water depth range of 145 to 1442 m increases by about 2parts per thousand with increasing depth. This is consistent with a composite temperature profile constructed from several hydrocasts in the various gulf basins. However, the delta18O water/salinity relationship is not sufficiently linear in gulf locations or in nearby open Pacific Geochemical Ocean Sections Study (GEOSECS) stations to be useful in solving paleotemperature equations. Of the most common benthic foraminifera, only Planulina ariminensis has delta(13)C that is consistent with the measured delta(13)C of SigmaCO(2). Several cores in the depth range 500 to 900 m have the laminated Holocene and Bolling/Allerod sediments, and the nonlaminated glacial age and Younger Dryas sediments that are typical of the gulf and other locations such as Santa Barbara Basin. The best of those, Jumbo Piston Core (JPC) 56 from 818 m water depth on the western margin of Guaymas Basin, was sampled for intensive study. Oxygen isotope ratios in benthic and planktonic foraminifera show little evidence for deglacial temperature oscillations. Carbon isotope ratios are generally lower during warm epochs, but the most striking result is strongly lowered benthic and planktonic delta(13)C about 9500 years ago. This may reflect water column oxidation of locally released methane. Neither benthic delta(13)C in depth section nor paired benthic and planktonic (14)C data in JPC56 are consistent with increased intermediate water ventilation during the glacial maximum and Younger Dryas. Likewise, (14)C data from 5 pairs of foraminifera from the Okhotsk Sea fail to support better ventilation in that basin during the last glacial maximum.},
	issn = {0916-8370},
	doi = {10.1023/A:1015830313175},
	author = {Keigwin, L. D.}
}
@article {2117,
	title = {Ocean ventilation and sedimentation since the glacial maximum at 3 km in the western North Atlantic},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {3},
	year = {2002},
	note = {565rlTimes Cited:26
Cited References Count:43
},
	month = {Jun 22},
	abstract = {[1] Stable isotope, sedimentological, and radiocarbon data from cores at similar to 3 km water depth on the Blake Ridge, western subtropical North Atlantic, reveal the history of deep water ventilation since the last glacial maximum (LGM). Bulk sediment accumulation rates varied locally by a factor of 2 under the influence of bottom currents in this sediment drift environment, but the sand flux, mostly foraminifera, was nearly identical at a given time. This suggests that the rain rate of foraminifera (mostly planktonic) was constant, that transport of foraminifera was negligible, and that current-controlled differences in clay and silt transport drive bulk accumulation. In two of the cores, flux peaks in the benthic foraminifera Cibicidoides and Uvigerina peregrina occurred during the Younger Dryas (YD) cold event, and at 18.2, 19.6, 21.1, 25.0, and 28.1 ka. Radiocarbon measurements on those benthic foraminifera show the ventilation age of bottom waters was similar to 1000 years during the YD, and for older events it was as great as 2000 years. These results contrast with Holocene ventilation, which was similar to 500 years and 700 years at 1500 years and similar to 7100 years before present, respectively.},
	keywords = {abyssal circulation, benthic foraminifera, c-14 ages, Calibration, climate-change, deep-water, Holocene, Last glacial maximum, ocean ventilation, radiocarbon, radiocarbon age, sea, sediment drifts, Younger Dryas},
	isbn = {1525-2027},
	doi = {10.1029/2001GC000283},
	author = {Keigwin, L. D. and Schlegel, M. A.}
}
@article {700,
	title = {Spatial and temporal offsets between proxy records in a sediment drift},
	journal = {Science},
	volume = {298},
	year = {2002},
	note = {612mqTimes Cited:147Cited References Count:38},
	month = {Nov 8},
	pages = {1224-1227},
	abstract = {Chronologies for Late Quaternary marine sediment records are usually based on radiocarbon ages of planktonic foraminifera. Signals carried by other sedimentary components measured in parallel can provide complementary paleoclimate information. A key premise is that microfossils and other indicators within a given sediment horizon are of equal age. We show here that haptophyte-derived alkenones isolated from Bermuda Rise drift sediments are up to 7000 years older than coexisting planktonic foraminifera. This temporal offset, which is apparently due to lateral transport of alkenones on fine-grained particles from the Nova Scotian margin, markedly influences molecular estimates of sea surface temperatures. More broadly, the observation raises questions about both the temporal and the geographic delity of paleoenvironmental records encoded by readily transported components of sediments.},
	issn = {0036-8075},
	doi = {10.1126/science.1075287},
	author = {Ohkouchi, N. and Eglinton, T. I. and Keigwin, L. D. and Hayes, J. M.}
}
@article {2190,
	title = {Detecting holocene changes in thermohaline circulation},
	journal = {Proc Natl Acad Sci U S A},
	volume = {97},
	year = {2000},
	note = {Keigwin, L DBoyle, E A
eng
Research Support, U.S. Gov{\textquoteright}t, Non-P.H.S.
2000/03/04 09:00
Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1343-6.
},
	month = {Feb 15},
	pages = {1343-6},
	abstract = {Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.},
	keywords = {*Climate, *Plankton, Animals, Atlantic Ocean, carbon isotopes, ice, oxygen isotopes, time},
	isbn = {0027-8424 (Print)0027-8424 (Linking)},
	doi = {10.1073/pnas.97.4.1343},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/10677463},
	author = {Keigwin, L. D. and Boyle, E. A.}
}
@article {2230,
	title = {The slope water current over the Laurentian Fan on interunnual to millennial timescales},
	journal = {Science},
	volume = {286},
	year = {1999},
	note = {id: 113},
	month = {1999},
	pages = {520-523},
	author = {Keigwin, L. D. and Pickart, R. S.}
}
@article {775,
	title = {Glacial-age hydrography of the far northwest Pacific Ocean},
	journal = {Paleoceanography},
	volume = {13},
	year = {1998},
	note = {105bqTimes Cited:192Cited References Count:61},
	month = {Aug},
	pages = {323-339},
	abstract = {Stable isotope data on benthic foraminifera from more than 30 cores on the northern Emperor Seamounts and in the Okhotsk Sea are synthesized in paleohydrographic profiles spanning the depth range 1000-4000 m. Holocene (core-top) benthic foraminiferal delta(18)O and delta(13)C data are calibrated to modern hydrographic properties through measurements of delta(13)C of Sigma CO2 and delta(18)O of seawater. Cibicidoides stable isotope ratios are close to the delta(13)C and equilibrium delta(18)O of seawater, whereas Uvigerina delta(18)O and delta(13)C are variably offset from Cibicidoides. Glacial maximum delta(13)C of Cibicidoides displays a different vertical profile than that of the Holocene. When results are adjusted by +0.32 parts per thousand to account for the secular change in delta(13)C during the last glacial maximum, the data coincide with the modern seawater and foraminiferal curves deeper than similar to 2 km. However, at shallower depths delta(13)C gradually increases by as much as 1 parts per thousand above the modern value. Furthermore, above 2 km the benthic delta(18)O decreases by similar to 0.5 parts per thousand. These results are consistent with a benthic front at similar to 2 km in the North Pacific [see Herguera et al., 1992], but they differ from interpretations based on trace metal data which indicate a source of nutrient-depleted deep water during glaciation. The isotopic data suggest that during glaciation there was a better ventilated watermass at intermediate depths in the far northwestern Pacific, it was relatively fresher than deep waters there, and deep waters were as nutrient-rich as today.},
	issn = {0883-8305},
	doi = {10.1029/98pa00874},
	author = {Keigwin, L. D.}
}
@article {2329,
	title = {The Little Ice Age and Medieval Warm Period in the Sargasso Sea},
	journal = {Science},
	volume = {274},
	year = {1996},
	note = {Keigwineng
1996/11/29
Science. 1996 Nov 29;274(5292):1504-8.
},
	month = {Nov 29},
	pages = {1504-8},
	abstract = {Sea surface temperature (SST), salinity, and flux of terrigenous material oscillated on millennial time scales in the Pleistocene North Atlantic, but there are few records of Holocene variability. Because of high rates of sediment accumulation, Holocene oscillations are well documented in the northern Sargasso Sea. Results from a radiocarbon-dated box core show that SST was approximately 1\&deg;C cooler than today approximately 400 years ago (the Little Ice Age) and 1700 years ago, and approximately 1\&deg;C warmer than today 1000 years ago (the Medieval Warm Period). Thus, at least some of the warming since the Little Ice Age appears to be part of a natural oscillation.},
	isbn = {1095-9203 (Electronic)0036-8075 (Linking)},
	doi = {10.1126/science.274.5292.1504 },
	url = {https://www.ncbi.nlm.nih.gov/pubmed/8929406},
	author = {Keigwin, L. D.}
}
@article {752,
	title = {Climate-Change - the North Pacific through the Millennia},
	journal = {Nature},
	volume = {377},
	year = {1995},
	note = {Rz336Times Cited:6Cited References Count:14},
	month = {Oct 12},
	pages = {485-486},
	issn = {0028-0836},
	doi = {10.1038/377485a0},
	author = {Keigwin, L. D.}
}
@article {783,
	title = {The Marine Record of Deglaciation from the Continental-Margin Off Nova-Scotia},
	journal = {Paleoceanography},
	volume = {10},
	year = {1995},
	note = {Th675Times Cited:85Cited References Count:77},
	month = {Dec},
	pages = {973-985},
	abstract = {Continental margin sediments off Nova Scotia accumulate at high rates (up to 360 cm kyr(-1)) and contain a history of millennial-scale environmental changes which are dominated by the proximity of the Laurentide ice sheet during the latest Quaternary. Using ratios of oxygen, accelerator mass spectrometer radiocarbon dating, micropaleontology, and sedimentology, we document these changes in six piston cores ranging in water depth from similar to 450 to similar to 4300 m. We find that maximum delta(18)O in N. pachyderma occurred about 15 ka and preceded the maximum abundance of this species in these cores by similar to 1000 years. Between 13 and 14 ka we find a second peak in abundance of N. pachyderma, minimum delta(18)O, and two pulses of ice rafting. The sediment lithology supports terrestrial studies which indicate that there was a general withdrawal of ice beyond the upper Paleozoic and Mesozoic red beds by 14 ka in southeastern Canada, so the ice rafting events between 13 and 14 ka probably reflect ice stream activity in the St. Lawrence valley. The Younger Dryas event is recognized as a peak in abundance of N. pachyderma and ice rafting (dated as similar to 11.3 ka), but meltwater discharge to the Gulf of St. Lawrence was either too small or occurred over too long a time to leave a distinct delta(18)O minium off Nova Scotia. At 7.1 ka, in the middle of Holocene warming, we find a third peak in abundance of N. pachyderma and another delta(18)O minimum but no ice rafting. We interpret these data as evidence of a late-occurring meltwater event which, if correct, could have originated in the Great Lakes, in the Labrador-Ungava region, or in both. The final millennial-scale phenomenon off Nova Scotia is the onset of {\textquoteright}{\textquoteright}Neoglaciation,{\textquoteright}{\textquoteright} marked by increased ice rafting and increased \% N. pachyderma beginning about 5 kyr ago.},
	issn = {0883-8305},
	doi = {10.1029/95pa02643},
	author = {Keigwin, L. D. and Jones, G. A.}
}
@article {2373,
	title = {Application of AMS 14C dating to continental margin sediments off Nova Scotia},
	journal = {Eos, Transactions, American Geophysical Union},
	volume = {75},
	year = {1994},
	note = {id: 1247},
	month = {1994},
	pages = {199},
	author = {Keigwin, L. D. and Jones, G. A.}
}
@article {2383,
	title = {Lake-Level History of Lake-Michigan for the Past 12,000 Years - the Record from Deep Lacustrine Sediments},
	journal = {Journal of Great Lakes Research},
	volume = {20},
	year = {1994},
	note = {Nl348Times Cited:47
Cited References Count:29
},
	month = {1994},
	pages = {73-92},
	abstract = {Collection and analysis of an extensive set of seismic-reflection profiles and cores from southern Lake Michigan have provided new data that document the history of the lake basin for the past 12,000 years. Analyses of the seismic data, together with radiocarbon dating, magnetic, sedimentologic, isotopic, and paleontologic studies of core samples, have allowed us to reconstruct lake-level changes during this recent part of the lake{\textquoteright}s history.The post-glacial history of lake-level changes in the Lake Michigan basin begins about 11.2 ka with the fall from the high Calumet level, caused by the retreat of the Two Rivers glacier, which had blocked the northern outlet of the lake. This lake-level fall was temporarily reversed by a major influx of water from glacial Lake Agassiz (about 10.6 ka), during which deposition of the distinctive gray Wilmette Bed of the Lake Michigan Formation interrupted deposition of red glaciolacustrine sediment. Lake level then continued to fall, culminating in the opening of the North Bay outlet at about 10.3 ka. During the resulting Chippewa low phase, lake level was about 80 m lower than it is today in the southern basin of Lake Michigan.
The rise of the early Holocene lake level, controlled primarily by isostatic rebound of the North Bay outlet, resulted in a prominent, planar, transgressive unconformity that eroded most of the shoreline features below present lake level. Superimposed on this overall rise in lake level, a second influx of water from Lake Agassiz temporarily raised lake levels an unknown amount about 9.1 ka. At about 7 ka, lake level may have fallen below the level of the outlet because of sharply drier climate. Sometime between 6 and 5 ka, the character of the lake changed dramatically, probably due mostly to climatic causes, becoming highly undersaturated with respect to calcium carbonate and returning primary control of lake level to the isostatically rising North Bay outlet. Post-Nipissing (about 5 ka) lake level has fallen about 6 m due to erosion of the Port Huron outlet, a trend around which occurred relatively small (+/- approximately 2 m), short-term fluctuations controlled mainly by climatic changes. These cyclic fluctuations are reflected in the sedimentological and sediment-magnetic properties of the sediments.
},
	keywords = {lake michigan, ostracodes, radiocarbon, sedimentology, sediments, southern},
	isbn = {0380-1330},
	author = {Colman, S. M. and Forester, R. M. and Reynolds, R. L. and Sweetkind, D. S. and King, J. W. and Gangemi, P. and Jones, G. A. and Keigwin, L. D. and Foster, D. S.}
}
@article {2379,
	title = {The limnological and climate history of Lake Michigan from ostracode, stable-isotope, and magnetic susceptibility records},
	journal = {Journal of Great Lakes Research},
	volume = {20},
	year = {1994},
	note = {id: 1358},
	month = {1994},
	pages = {93-107},
	author = {Forester, R. M. and Colman, S. M. and Reynolds, R. L. and Jones, G. A. and Keigwin, L. D. and Foster, D. S.}
}
@article {755,
	title = {The Role of the Deep-Ocean in North-Atlantic Climate-Change between 70-Kyr and 130-Kyr Ago},
	journal = {Nature},
	volume = {371},
	year = {1994},
	note = {Ph254Times Cited:159Cited References Count:32},
	month = {Sep 22},
	pages = {323-326},
	abstract = {THE suggestion(1) that changes in North Atlantic Deep Water (NADW) production are linked through surface heat flux to the atmospheric temperature over Greenland is supported by earlier indications(2,3) that NADW production decreased during glacial times, and by the subsequent finding(4-6) that it declined during the Younger Dryas cool period at the end of the last glaciation. Changes in North Atlantic surface temperatures have been found? to mirror high-frequency temperature changes recorded in Greenland ice cores over the past 80 kyr, but the connection to abyssal circulation has yet to be established, except for one or two isolated oscillations(8,9). Here we present carbon and oxygen isotope analyses of benthic foraminifera in a high-resolution North Atlantic deepsea sediment core for the period 70-130 kyr ago. These data allow us to reconstruct the history of NADW production, which shows a close correlation with Greenland climate variability for much of this time interval, suggesting that the climate influence of NADW variability was widespread. We see no evidence, however, for changes in NADW production during substage 5e (the Eemian interglacial period), in contrast with recent ice-core data(10) which suggest severe climate instability in Greenland during this time period. Our results may support suggestions, based on data from a second ice core, that this apparent instability is am artefact caused by ice flow(11). Alternatively, the Eemian climate instability may have had a different origin from the subsequent climate events.},
	issn = {0028-0836},
	doi = {10.1038/371323a0},
	author = {Keigwin, L. D. and Curry, W. B. and Lehman, S. J. and Johnsen, S.}
}
@article {2381,
	title = {Two episodes of meltwater influx from glacial Lake Agassiz into the Lake Michigan basin: Contrasts in climatic and oceanographic effects},
	journal = {Geology},
	volume = {22},
	year = {1994},
	note = {id: 189},
	month = {1994},
	pages = {547-550},
	author = {Colman, S. M. and Keigwin, L. D. and Forester, R. M.}
}
@article {933,
	title = {Deep-sea sediments reveal},
	journal = {Oceanus},
	volume = {35},
	year = {1993},
	note = {id: 1248},
	pages = {89-92},
	author = {Lehman, Scott J. and Keigwin, L. D.}
}
