Sir Nicholas John Shackleton. 23 June 1937 −− 24 January 2006three children of robert Millner...

24 January 2006−−Sir Nicholas John Shackleton. 23 June 1937

Ian Nicholas McCave and Henry Elderfield

originally published online June 29, 2011, 435-462, published 29 June 2011572011 Biogr. Mems Fell. R. Soc.

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Sir NicholaS JohN ShackletoN23 June 1937 — 24 January 2006

Biogr. Mems Fell. R. Soc. 57, 435–462 (2011)

on January 20, 2017http://rsbm.royalsocietypublishing.org/Downloaded from

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Sir NicholaS JohN ShackletoN

23 June 1937 — 24 January 2006

elected FrS 1985

By Ian nIcholas Mccave and henry elderfIeld frs

Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK

Nick Shackleton was an international scientist of great renown who fundamentally changed our understanding of how earth processes work. his research on ancient oceans and climates was both innovative and pioneering, and he clarified the precise role of carbon dioxide in warming and cooling the earth’s climate. his work contributed greatly to our present under-standing of the mechanism and causes of global warming. When he began his research, the investigation of past climatic changes was an area of ‘academic’ interest only. Four decades later, his lifetime achievements define the emergence of our understanding of the operation of earth’s natural climate system. this understanding of the past is now central to efforts to predict the future climate we have begun to create. as well as his many scientific accomplish-ments, Nick Shackleton excelled in another area, that of music, which was almost as important to him as science, and he was a very accomplished clarinet player. in his work he was spirited and curiosity-driven. he let his students and an entire community share in his brilliance and vision.

early lIfe, and lIfe at caMBrIdge

Nick Shackleton was born on 23 June 1937 at 112 cheyne Walk, chelsea, london, the first of three children of robert Millner Shackleton (FrS 1971), a field geologist, son of John Millner Shackleton, an electrical engineer, and his wife Gwen isabel (née harland) (divorced in 1949), daughter of alfred John harland, a schoolmaster. he had a half-brother and half-sister by his father’s second marriage (1949–78) to Gertrude (Judith) Wyndham Jeffreys (1915–2000), and finally a second stepmother, geologist Dr Peigi Wallace (1940–2001), on his father’s third marriage in 1984.

http://dx.doi.org/10.1098/rsbm.2011.0005 437 this publication is © 2011 the royal Society



438 Biographical Memoirs

he was a distant relative (his grandfather was a second cousin) of the antarctic explorer Sir ernest Shackleton (1874–1922). he married, first in 1967, Judith carola Murray, who was then an undergraduate at Newnham college, daughter of the late henry Murray, a chemist. they were divorced in 1977. in 1986 he married Vivien anne law (1954–2002), a distin-guished linguistic scholar (FBa) who knew more than 100 languages and who, he claimed, could learn a new language reading a grammar over the breakfast table. tragically, she died, like Nick, of cancer, at the height of her powers, aged 49 years.

Nick’s father was a lecturer in geology at imperial college, london, and later Professor of Geology at leeds University (where he gave one of us (h. e.) his first job as a junior lecturer), specializing in african, and later himalayan, geology. robert Shackleton trav-elled widely for research and industry, spending 1940–45 in kenya searching for gold and strategic minerals, thereby giving Nick an early childhood on the african plains, out of the way of wartime london bombing. although his father was a distinguished geologist, Nick credited his mother with encouraging his scientific curiosity. as a young student, he often came home from school with some new morsel he had learned. if his mother knew some-thing about the subject, she would talk about it with him. if not, she and Nick would search for more information.

he attended cranbrook School, kent, as a boarder pupil from 1949 to 1956, followed by National Service in the Queen’s own royal West kent regiment, where, as Bandsman Shackleton (army no. 23313350) and already an accomplished clarinettist, he was secretary of the regimental band. he trained at catterick, and served in cyprus for a while. he entered clare college, cambridge, in 1958 to read Natural Sciences. he found several outlets for his enthusiasms, including music and athletics. Perhaps as a consequence, his undergraduate career was academically undistinguished. he was placed in the second class in Part i Prelim, lower seconds in Part i and Part ii, graduating Ba in physics in 1961. in the first two years of his degree he split his time about equally between physics and mathematics and, perhaps following his father, geology and mineralogy. in his final year he specialized in physics for Part ii of the Natural Sciences tripos.

an opportunIty arIses

on his graduation in 1961, what he later called ‘a series of random events’ led to his follow-ing his father into the earth sciences, but in a different direction. the random events were associated with the suggestion, made in about 1960 by Sir edward Bullard FrS, the head of Geodesy and Geophysics at cambridge University, that harry (later Sir harry) Godwin FrS, then head of the Sub-Department of Quaternary research (which was part of the Botany Department, of which Godwin also was head), should set up a laboratory in cambridge to measure stable isotopes. the reason for Bullard’s suggestion related to the work of the Nobel laureate harold Urey ForMemrS. in 1947 Urey had published calculations that predicted that the heavy isotope of oxygen (18o) would be fractionated from its light isotope (16o) as a function of temperature (Urey 1947). Professor of Botany harry Godwin had already set up a radiocarbon laboratory to make 14c age measurements. in 1960, Bullard, at that time reader in Geophysics, suggested that he add the determination of past temperature through oxygen isotopes. it so happened that Godwin was a Fellow and Bullard a member of clare college, where Shackleton was an undergraduate. Nick was offered and accepted the task for his PhD



Nicholas John Shackleton 439

of setting up the oxygen isotope palaeotemperature method (although that word had not then entered the scientific vocabulary).

Urey had suggested that measurements of 18o/16o ratios would provide a method of estimating temperatures in the geological past, from analysis of fossil shells composed of calcium carbonate minerals. he assembled a group of talented scientists who designed a mass spectrometer to test his theory, and in the early 1950s they demonstrated that it was correct. among this team was cesare emiliani, who, because of his background in micropalaeontol-ogy (the study of microscopic fossils), went on to apply the techniques developed to micro-fossils called foraminifera recovered from deep-sea cores. emiliani identified cycles of warm and cold sea surface temperatures back to more than half a million years ago; because of this work, emiliani is often thought of as the founder of palaeoceanography.

the work carried out by emiliani was extremely laborious, requiring a relatively large amount of material, and Shackleton realized that, to set up a successful laboratory, he needed to develop a mass spectrometer an order of magnitude more sensitive than that developed by Urey’s team. Nick’s seminal effort was to modify a mass spectrometer so that it could measure the mass ratio of the isotopes of oxygen in minute samples of calcium carbonate (1)*. Samples as small as 0.4 mg (representing about five to ten shells of the pinhead-sized fossil foraminifera common in marine sediments) could be measured to an accuracy of 1 part in 10 000.

he accomplished this as part of his thesis work and in 1967 received his PhD for a dis-sertation entitled ‘the measurement of palaeotemperatures in the Quaternary era’. he applied his method to make oxygen isotope measurements on shells of fossil foraminifera that lived in bottom waters (benthic) and those from surface waters (planktonic). From a comparison (figure 1), he saw a fatal flaw in emiliani’s work. emiliani had interpreted his results on plank-tonic foraminifera as an 8 °c change in surface temperature from the last ice age to today. Shackleton found that the changes in isotopic composition for benthic and planktonic spe-cies were about the same (figure 1), yet for the deep sea this temperature change was clearly impossible: the deep-sea water temperature today is less than about 2 °c and the freezing point of sea water is about −2 °c. the dominant cause of oxygen isotope variations was not temperature, but changes in the oxygen isotope composition of the oceans caused by removal of isotopically depleted water to form the ice sheets. in a spirit that typified Shackleton’s gen-erosity throughout his career he wrote in his Nature paper in 1967 reporting this crucial result in the year of his PhD (2):

it should be emphasised that the time sequence which emiliani has been able to obtain … remains of inestimable value … in a sense it is enhanced by the certainty that it is a time sequence for terrestrial glacial events rather than oceanographic events.

in 1965, during the course of his PhD research, Nick was appointed as Senior assistant in research (equivalent to a junior lectureship, although he did little teaching) in the Sub-Department of Quaternary research in the Department of Botany at cambridge University, a position he held until 1972, when he became assistant Director of research in the sub-department. in 1988 he was appointed Director of the sub-department and, in 1995, Director of what by then was called the Godwin institute of Quaternary research, a post he held until 2004, when he retired. to add to the complexities of cambridge appointments, he was elected

* Numbers in this form refer to the bibliography at the end of the text.




ad hominem reader, cambridge University, from 1987 to 1991, and ad hominem Professor of Quaternary Palaeoclimatology from 1991 to 2004. he was also a research Fellow at clare hall, cambridge, from 1974 to 1980, and Fellow from 1980 to 2004.

glacIatIon

As we have outlined, the seminal realization that the record of benthic δ18o (by which we mean the δ18O of benthic foraminiferal calcite; δ18o is a measure of the 18o/16o ratio) was dominated by ice volume had obvious consequences for the interpretation of glacial events on the continents: the onset and waxing and waning of ice sheets. clearly, also, more ice on land meant less water in the sea and thus insights into the history of sea level. Nick’s key associates in this work were Neil opdyke (lamont–Doherty Geological observatory), Jim kennett (University of rhode island) and, for sea level, John chappell (australian National University) (34). the classic paper with opdyke (5) set out the arguments for a close relation-ship between isotopic values, ice volume and sea level, with a 1‰ shift in δ18o representing about 100 m (figure 2).

one might therefore see it as perverse that in 1975 Shackleton and kennett (S&k) (8, 13) discovered and interpreted the biggest shift in benthic δ18o in the past 50 million years (50 Ma), occurring in the early oligocene, as having been solely due to major cool-ing of bottom water rather than the presently accepted view that it records the onset of antarctic glaciation plus bottom water cooling (Miller et al. 1991; Zachos et al. 1993; lear et al. 2000). however, it must be remembered that at that time there was no rigorous

Figure 1. oxygen isotopic composition of benthic (benthonic) foraminifera from a caribbean Sea core plotted against oxygen isotopic composition of planktonic foraminifera. Note that the ranges in values of δ18o for planktonic species (abscissa) and benthic species (ordinate) are both about 2‰. (reprinted from (2) with permission from Macmillan Publishers ltd. copyright © 2011.)




method of separating the contributions of temperature and seawater δ18O to benthic δ18o, which is now available through Mg/ca palaeothermometry (lear et al. 2000). S&k (8) maintained that the onset of antarctic glaciation came at the second isotopic step in the mid-Miocene (figure 3). the S&k argument was based on calculation of temperature by the equation that Shackleton had just devised, which was valid for low temperatures found at the sea floor (6):

T = 16.9 − 4.38(δ18oc − δ18ow) + 0.10(δ18oc − δ18ow)2,

where δ18oc = δ18O of foraminiferal carbonate and δ18ow = δ18o of ocean water. the iso-topic composition of the ocean before the formation of the present ice sheets was estimated at −1.2‰ (in contrast with the modern value, −0.28‰) on the basis of the fact that the ice now stored in antarctica is isotopically more negative. S&k (8) also assumed ‘that there was insignificant antarctic ice up to the … middle Miocene’, this assumption being based on a further assumption that bottom waters would have remained more or less constant from the time that the antarctic ice sheet started to accumulate. it is clear from this and other papers around that time that palaeoceanographers struggled to extract palaeotemperatures that they knew were embedded in their measurements of benthic δ18o. S&k (8) further justified their approach with the complex (and difficult to decipher) argument that

there is a trend to lower deep temperatures through the eocene, culminating in a value of about 5 °c in the early oligocene. if the value had not been corrected by assuming the absence of the antarctic ice sheet, the value yielded at this point would have corresponded to a temperature of about 9 °c. Such a value would of course be incompatible with the presence of a major ice sheet extending to the coast. thus the assumption that the ice sheet was not present is strongly supported by observations.

Zachos et al. (1992, 1993) made a different assumption, namely that deep water tem-peratures never fell below 1 °c, which puts a lower limit on ice volume: when equilibrium δ18o values exceeded 2.4‰, continental ice must have existed. on that basis they inferred

Figure 2. isotope records from core V28-238 (western equatorial Pacific), showing similar amplitudes of both benthic and planktonic foraminifera. this reflects mainly ice volume and hence sea level. the two sequences are plot-ted to the same scale of isotopic change but with scale zero-points differing by 5.3‰, the present-day plank-tonic–benthic difference. (reprinted from (5) with permission from elsevier. copyright © 2011.)




(a)

(b)

Figure 3. (a) Detail from the isotopic record from late Eocene to early Oligocene, showing a sharp increase in δ18o interpreted as a large decrease in bottom temperature. (reprinted from (13) with permission from Macmillan Publishers ltd. copyright © 2011.) (b) From left to right: deep-sea temperatures based on Mg/ca, compilation of δ18o (based on Miller et al. (1991)) and estimation of seawater δ18o (lear et al. 2000), where the shift is seen as the onset of major Southern hemisphere glaciation. (adapted from lear et al. 2000; reprinted with permission from aaaS.) (online version in colour.)




glaciation—a transient ice sheet—in the early oligocene. the palaeotemperature data of lear et al. (2000) confirm that most of the benthic δ18o signal results from a build-up of continental ice with little temperature response.

in the work with kennett on the New Zealand DSDP cores, Shackleton also inferred the onset of major Northern hemisphere glaciation at 2.6 Ma ago (9). this was later confirmed in the North atlantic, where Shackleton and his colleagues dated (by isotopes, magnetic revers-als and biostratigraphy) the first minor layers of ice-rafted detritus at 2.5 Ma ago and full ice sheet delivery of ice-rafted debris (irD) at 2.4 Ma ago (31). Further work with kennett (7) on planktonic foraminifera in the Gulf of Mexico provided the first inference from isotopic data of the presence of meltwater from the Mississippi resulting from glacial retreat. olausson (1965) had earlier given careful consideration to the isotopic composition of ice sheets (aided by Willi Dansgaard, with whom Shackleton shared the crafoord Prize) and concluded that (i) emiliani’s Pacific data (emiliani 1955a) did not record a significantly lower temperature in the Glacial and (ii) his Mediterranean data (emiliani 1955b) showed that the ‘rapid and too early rise in the isotopic temperature curve cannot be due to a rapid warming of the ocean. it must be due to meltwater contamination of the surface water.’ thus the principle of deducing meltwater from isotopes was not new, but the history of laurentide decay was.

clIMap and specMap

one application for this time sequence referred to above was to identify isotopically the hor-izon of the last ice age in ocean cores worldwide, which provided the temporal framework for a large US-driven project in which Shackleton participated, called cliMaP (climate: long-range investigation, Mapping, and Prediction). this generated a global map of sea surface temperature, inferred from foraminiferal abundances, at the last Glacial Maximum (lGM) (10, 22). the map was used by modellers to reconstruct atmospheric circulation in glacial times and as a boundary condition in models that explored changes in atmospheric tempera-ture, which were of crucial importance for modelling future climate.

this set the stage for the most important application of the oxygen isotope method: the reconstruction of the history of global ice volume through the ice ages. Milutin Milankovitch in the 1920s had hypothesized that ice ages were caused by changes in distributions of solar radiation at the earth’s surface, which were in turn driven by changes in movement of the earth’s orbit.

Shackleton and his US co-workers Jim hays (of the lamont–Doherty Geological observatory of columbia University, where Shackleton was appointed Senior Visiting research Fellow in 1974) and John imbrie (of Brown University) generated long climate and isotopic records from different ocean regions and subjected the patterns to mathemati-cal (spectral) analysis. the result was the famous 1976 paper in Science (‘Variations in the earth’s orbit: pacemaker of the ice ages’ (11)), where they showed that the three periodicities with which the earth’s orbit changes (100 000 years, 40 000 years and 21 000 years) were all present in the temperature, isotopic and fossil records, just as predicted (figure 4).

assembly of more, longer and higher-resolution records now became the focus of the suc-cessor project, SPecMaP (the Mapping Spectral Variability in Global climate Project), which used a stacked oxygen isotope stratigraphy and four different ‘orbital tuning’ approaches. the resulting tuned chronology had an average error of ±5000 years over a 300 ka record (35).




this clear recognition of orbital control is also now revolutionizing the whole of stratigra-phy (the study of geological strata) because it provides in principle a means of correlating beds at separated parts of the earth to a precision of 20 000 years at a time of hundreds of millions of years ago, and of determining precise ‘orbitally tuned’ age-calibrated stratigraphies back to about 250 Ma ago (laskar et al. 2004).

orBItal tunIng of the pleIstocene tIMe scale and Its consequences

Challenge to the primacy of radiometric datingin the early days of isotope stratigraphy, potassium–argon dates on volcanic ash were useful checks on the age of isotope stage boundaries, starting with the marine isotope 5/4 stage bound-ary at about 75 ka ago. a key method for correlation between cores is through the stratigraphic record of earth’s magnetic reversals. once dated in volcanic ash layers and piles of lava by

Figure 4. Spectra of variations in (a) orbital obliquity and precession (Δe sin Π), (b) insolation at 60° N, (c) sea surface temperature and (d) δ18o as a function of frequency (cycles per thousand years). (c) and (d) are based on an analysis of two sub-antarctic deep-sea cores. Note the excellent match between orbital and climatic variables and the strong presence of a peak with a period of about 100 ka. insolation variance at this period is very weak, and this reveals a problem of palaeoclimatology that remains unsolved. (reprinted from (11) with permission from aaaS.)




the k–ar method, recognition of these in cores provided a quick age scale. after revision of the 40k decay constants, the age of the Matuyama–Brunhes reversal boundary (MBB) was revised to 730 ka. a SPecMaP orbitally tuned chronology of imbrie and colleagues (29) agreed with that age, but later SPecMaP work recognized sufficiently high-quality records only to 300 ka ago (35). the 730 ka age was adopted by ruddiman et al. (1986), who retuned the underlying section to obliquity with the same result (but fixed to k–ar dated reversals lower in the section).

it is a matter of interest as to why the nearly correct astronomical re-dating of MBB by Johnson (1982) giving an age of 790 ka was not widely adopted. Johnson’s method was sim-ply to match extreme minima in benthic δ18o of the Shackleton & opdyke records (5, 14) to the astronomical time scale at points of low summer insolation during times of low orbital eccentricity. the reason perhaps lay in the fact that those involved in the tuning enterprise had evolved a more rigorous approach involving careful assessment of stratigraphic complete-ness, requirement of an adequate sedimentation rate to give the necessary resolution, spectral methods and bandpass filtering of characteristic frequencies of orbital components and precise orbital calculations. Johnson lacked most of these except the latter, which he got from Berger (1978). in addition, Johnson was an outsider to the priesthood that evolved from the cliMaP project that did this work (Shackleton, imbrie, Pisias, Berger, hays, Moore, Martinson, Prell, ruddiman and others).

oDP Site 677 was a re-coring of Site 504B with overlapping cores to produce a complete sequence of sufficient resolution through the MBB (40). this was used by Shackleton and his colleagues (41) to do a rigorous tuning of the section from 330 to 800 ka. they obtained an age for the MBB of 780 ka, a value very close to the modern accepted value of 778 ka (izett & obradovich 1994) (52). Subsequently Bassinot and colleagues (46) deduced an age of 775 ka.

this presented a clear problem for radiometric dating, and Shackleton and his colleagues (41) suggested that maybe the geochronologists should look to their decay constants. the problem, however, was partly more mechanical, residing in argon retention and loss. this was solved by development of the 40ar/39ar method that requires only ratios of argon isotopes, rather than absolute amounts, for the calculation of an age. these methods gave the ‘correct’ answer, 778 ka (izett & obradovich 1994). the orbital tuning led the way and set the scene for further refinements. Notably, the Fish canyon tuff, used as a standard in the geological time scale (Gradstein et al. 2004), with an ar–ar age of 28.02 Ma, was orbitally dated to 28.201 ± 0.046 Ma ago (kuiper et al. 2004). this was achieved via the 40ar/39ar dating of the already astronomically dated Melilla tephras, which can be converted to an astronomically calibrated age for Fish canyon sanidine (Fcs) by treating the Melilla sanidines as astronomi-cally dated standards and Fcs as the unknown (kuiper et al. 2004, 2008). although the decay constant has been revised from (5.543 ± 0.020) × 10−10 per year to (5.463 ± 0.214) × 10−10 per year (Min et al. 2000), the astronomically calibrated age of the tuff is now the primary stand-ard. resulting from this, the cretaceous/tertiary boundary has been re-dated to 65.95 Ma ago (kuiper et al. 2008). thus the ‘confrontation’ produced by Shackleton’s careful tuning at the MBB has spread like wildfire through dating of the cenozoic and is set to continue through the Mesozoic as well.

Implications for planetary dynamicsorbital tuning requires a source of high-quality calculations of insolation. Shackleton’s col-laborations, first with andré Berger from the institute of astronomy in louvain and latterly




with the astronomer Jacques laskar at the Bureau des longitudes in Paris, fulfilled that need. the success of the orbital tuning approach led to some contributions in the opposite direction because the geological record has very long ‘observation’ times relative to those of astronomy. two papers (58, 65) with his student heiko Pälike and laskar stand out.

on the basis of interference patterns between the precession and obliquity components of geological data and astronomical solutions, they extracted small changes in the precession constant p due to tidal dissipation over the past 25 million years and constrained the param-eters for tidal dissipation and the dynamical ellipticity of the earth (58). these parameters were shown to have remained close to the present-day values over that time. this most helpful result indicated that, by using present-day values for dynamical ellipticity and tidal dissipation in calculating insolation by la93 (laskar et al. 1993), large errors are not introduced during astronomical tuning.

a second study (65) examined the chaotic behaviour of solutions to calculations of earth’s orbit. Because the Solar System is chaotic, the duration over which earth’s orbital variations can be computed with confidence is limited. one of the main identified mani-festations of chaos is the transition in the ratio of two resonant astronomical frequencies, evidence of which can potentially be detected in the rock record. Geological data differenti-ate between astronomical solutions that exhibit a transition since 40 Ma ago and those that do not. the chaotic diffusion of the Solar System in the past can thereby be constrained, a significant result for astronomical models. a corollary of this work was support for the new astronomical model of laskar et al. (2004) and the revised, younger age of the oligocene–Miocene (o–M) boundary of about 23 Ma (64). this negated the age of 24.0 Ma obtained from the cape roberts Project crP-2a core via 40ar/39ar data for ages of polarity chrons in the vicinity of the o–M boundary (Wilson et al. 2002), another confrontation won by tuning. More recent work by laskar has improved astronomical solutions of Solar System orbits further, and has now shown that the long-term (405 000-year) variation of earth’s eccentricity is very stable, and will allow the astronomical calibration of the geological time scale to venture into the early cenozoic and beyond.

δ13c, co2 and deep cIrculatIon

Shackleton pioneered the use and interpretation of carbon isotopes in palaeoclimate studies, an undertaking in which he moved on from studying the orbital forcing of glacial cycles to the positive feedbacks that amplify this forcing into dramatic changes in climate. oxygen isotope determinations are made via the conversion of microfossil carbonate into co2 gas, and the method also generates carbon isotope data, which previously were recorded but not examined. recognizing that the carbon isotopic composition of the oceans is affected by the amount of carbon stored on land, in a famous paper in 1977 Shackleton used carbon isotopes to assess the changing land reservoir of carbon between glacial and interglacial times (15).

he also pioneered the use of carbon isotopes in palaeoclimate studies. here he applied the carbon isotope method to test an idea suggested by Wally Broecker of lamont–Doherty observatory to explain changes in the co2 content of the atmosphere between ice ages and today. the first reports had appeared, from work on air trapped as bubbles in ice cores, that co2 concentrations at glacial times were about 190 parts per million compared to 280 parts per million in pre-industrial times. Broecker argued that the only way that this




could have occurred was by the transfer of carbon to the deep ocean by increased biologi-cal productivity.

Because this process would preferentially enrich the lighter 12c isotope in organic matter sinking to the sea floor, it should produce larger differences in the ratio of 13c to 12c between surface and deep seawater at glacial times as recorded in the foraminifera shells. Shackleton’s record, published in 1983 in Nature (25), predicted how atmospheric co2 has changed over the past 100 000 years; this result was found to be very similar to that obtained from bubbles in the antarctic Vostok ice core.

in 1980 Shackleton’s colleague Jean-claude Duplessy had shown variation in the source and strength (its origin and transport) of North atlantic Deep Water (NaDW) by means of oxygen isotopes (Duplessy et al. 1980), and in 1983 Shackleton and his colleagues (26) used carbon isotopes to the same end, demonstrating a large gradient between North atlantic and eastern Pacific. oxygen isotope records were found to be very similar, unlike those for carbon isotopes. the atlantic–Pacific carbon isotope gradient showed that the production of NaDW varied during the late Pleistocene, and that the pattern of variation was not simply related to the oxygen isotope record. oxygen isotope records of inter-oceanic gradients supported the hypothesis that in the glacial the North atlantic was colder, and less oxygenated, than it is today. Shackleton also noted that his 1977 interpretation, in which the carbon isotope record from the atlantic reflects changes in the terrestrial biomass, was an oversimplifica-tion: ageing of deep water with supply of light carbon from decaying phytoplankton was seen to be important as well. this insight was followed up in several papers with Duplessy (27, 28, 33, 36, 37).

Finally, these threads came together in 1988 with the first successful determination of the radiocarbon age of Pacific deep water, at the far end of what Broecker called the ‘conveyor’, where Shackleton and his French colleagues (who had an accelerator necessary for making 14c age determinations on the relatively rare benthic foraminifera) showed that the glacial age was about 500 years more than modern (38). land-to-ocean carbon transfer plus the more sluggish deep circulation had allowed a build-up of higher nutrient concentrations in deep water, making it more corrosive to carbonate sediments.

suB-orBItal changes

although Shackleton was the major figure in spectral analysis of the records and determina-tion of changes on Milankovitch time scales, workers on Greenland ice cores had shown in the 1980s (and confirmed in the 1990s) much sharper changes at higher frequencies (periods of 1–10 ka) that were not strongly periodic (Johnsen et al. 1992; Dansgaard et al. 1993) and were thus unlikely to be astronomically driven. Bond and colleagues (Bond et al. 1993; Bond & lotti 1995) demonstrated that these were matched by changes in sea surface temperature and ice discharge in the central North atlantic. these so-called Dansgaard–oeschger (D–o) cycles had abrupt warmings occupying a few decades and slower coolings, periodically culminating in a ‘heinrich event’, a collapse of the ice sheet with massive iceberg discharge.

We would not say that this work passed Shackleton by, but his involvement in the investiga-tion of fine-scale changes was mainly through his students Mark chapman and Mark Maslin (North atlantic) and isabel cacho (western Mediterranean) (49, 59, 60). there was, however, one study by him that has proved hugely influential (63). the French development of a long




piston corer deployed from the vessel Marion Dufresne allowed the collection of cores with a high sedimentation rate, giving high resolution. one of these from the Portuguese margin (core MD95-2042) revealed key insights (63). oxygen isotope measurements on glacial-age (isotope Stage 3) planktonic foraminifera (Globigerinoides bulloides) were seen to resemble closely the pattern of temperature change in Greenland (GRIP) (from the δ18o ratio in ice), whereas those in the infaunal benthic foraminifera (Globobulimina affinis) were very like the antarctic temperature record (ice deuterium-to-hydrogen (D/h) ratio) in the Vostok ice core (see figure 5). in the planktonic record the same sharp increases in temperature as those in GriP suggested a secure basis for correlation and transfer of the GriP age scale to the marine core. The benthic δ18o record provides evidence of change in continental ice volume and cor-relates well with the Vostok temperature record. Vostok and GriP are synchronized through their methane content, so the north–south age relation seen in the one core is robust (figure 5). the sea bed at the core’s depth of 3146 m off Portugal in the Glacial was bathed in northward-flowing water of circum-antarctic origin; hence the correlation.

Shackleton’s close connection with the ice-core community was also evident in his use of the result of the MD95-2042 paper to devise a new age scale for the cyclic D–o Stage 3 section of the GriP ice core (66). this involved new 14c dates, correlation to U-series dated cave speleothems and corals and correlation to Greenland and antarctic ice cores. the authors concluded:

By utilizing the geologist’s approach of precise stratigraphic correlation, it is possible to modify glaciological age models for ice cores collected from Greenland and antarctica in such a manner that they are mutually consistent to within a very few hundred years.

Figure 5. Benthic and planktonic δ18O in Stage 3 in core MD95-2042 with δ18o from Greenland (GriP) and D/h from antarctic (Vostok) ice cores. Numbering of GriP interstadials is indicated; crosses identify the age control points correlating the marine core to GriP. (reprinted from (63) by permission of american Geophysical Union. copyright © 2011 american Geophysical Union.)




this exercise exemplifies a very important aspect of Shackleton’s approach: stratigraphy and precise chronology. In this case the payoff was a record of the Δ14c values associated with the laschamp event, a brief collapse of the earth’s magnetic field that caused increased 14c production.

shackleton and the terrestrIal quaternary

Being based in an institute founded on palaeobotany, Shackleton’s earliest work related marine records to terrestrial records. ever since emiliani’s studies (emiliani 1955a, 1966) the question had arisen as to how the classic four glacials of the alps and North america could fit with his sequence, which pointed to many more than four cycles. in his second paper on the Quaternary (3), Nick and charles turner (a palaeobotanist) argued that emiliani’s marine sequence of glacials/interglacials was more likely to be correct than that given by the marine micropalaeontological interpretations of the time. Shackleton and turner gave strong support to emiliani and made some pointed remarks that indicated the turmoil in the Quaternary com-munity caused by his results: ‘the fact that the record obtained by emiliani is more complex than the classical picture of the timing of the ice ages cannot any longer be taken to imply that it is wrong’; ‘it is not sufficient to identify the largest events with the best known names and leave it at that …’; and finally, ‘… although Glass et al. (1967) have obtained a complete and reproducible sequence … the micropalaeontological record which they have obtained bears little relation to the chronology of glacial events in europe.’

it did not take long for the world to come around to the Shackleton–emiliani view; after all the evidence for many more than four changes in ice volume was indeed strong. the problem remained as to how to slot in the warm and cold periods inferred from pollen in land sections that were often separated by hiatuses, many of which were undetected. one promising approach was to find pollen in marine strata in which an isotope stratigraphy could be determined. From early in his career Shackleton had been associated with lamont–Doherty Geological observatory in New York. also an associate there in the 1970s was linda heusser, then of New York University, a pollen specialist. together they showed in a marine core an excellent record of glacial–inter-glacial vegetation changes in the US Pacific Northwest tied to an isotope stratigraphy (20). although this set the standard for future work, particularly off Portugal by Shackleton’s student katy roucoux and associate chronis tzedakis, it did not finally fix the general problem of marine–terrestrial correlation, which still remains outstanding. this is because fragmentary pol-len records can show whether deposits record warm or cold conditions, but, given that ten cold periods occurred in the past million years, which one is the dated marine sequence?

a new approach to the problem uses the increasingly long and complete lake sequences in europe, work with which Nick was closely involved (55). a time scale for the four long-est pollen sequences in europe was developed by tuning the terrestrial records to the marine isotopic stratigraphy (the SPecMaP stack (35)) using glacial–interglacial transitions as the tie points. Differences and similarities of individual temperate stages were analysed by using the combined records of several taxa representing the forest succession from all sites. a complete stratigraphy of major vegetation events for the last 430 ka now gives a potential system for terrestrial biostratigraphical correlation with age control.

another way of doing the correlation is the direct dating of terrestrial deposits. this led Shackleton into the world of loess, deposits of wind-blown dust. indeed, one of his earliest papers




(4) puts data showing greater glacial trade wind vigour together with an 800 ka-long planktonic δ18o record. a first attempt at direct dating of loess by thermoluminescence was remarkably suc-cessful, with an age for a last interglacial soil of 115 ± 10 ka (compared with 126–118 ka from marine stratigraphy) (32). Next a direct comparison was made between the magnetic suscepti-bility stratigraphy of chinese loess and dust accumulation rate in a Pacific core with an isotope record dated to 500 ka ago (39). Soils in loess correspond to warmer, wetter conditions, slower deposition on land and at sea, and higher magnetic susceptibility in the iron-rich soils. thus the dated marine climate record was transferred to terrestrial deposits with far-reaching consequences, especially in china. li Ping Zhou came to Nick’s laboratory to work on loess stratigraphy, lumi-nescence dating and magnetostratigraphy. the latter area yielded key insights into pitfalls in applying magnetic reversal stratigraphy in terrestrial loess sections. the problem was that the last

Figure 6. Nick in his office at the Godwin laboratory in Free School lane. he is exactly as he would greet a visi-tor sitting at a narrow bench next to the single window (looking out onto a brick wall), picking foraminifera. (Photograph taken by Neville taylor of cambridge University, Photographic and illustration Services.) (online version in colour.)




full magnetic field reversal, the MB boundary 778 ka ago, occurs in a warm marine isotope stage (no. 19), but in cold climate loess (rather than in the overlying warm soil where it ‘should’ be). the source of the problem is the lock-in depth of the magnetic signature, which was shown to be several metres down from the contemporary land surface, and up to 10 ka too old (57).

shackleton’s IMpact on MarIne MIcropalaeontology and palaeoMag-netIc work

Because Shackleton’s work was centred on the isotopic analysis of carbonate shells of micro-fossils, especially foraminifera, he became highly proficient in this area. he was adept at recognizing species and picked most of the samples that he analysed, a most effective form of quality control (figure 6). he also interacted with a host of micropalaeontologists and had sev-eral PhD students who worked on foraminifera and nannoplankton (coccoliths and discoast-ers). in his palaeontological work three areas stand out: synchroneity/diachrony of speciation and extinction datum levels, orbital forcing and productivity changes, and foraminiferal habi-tats. Most of Shackleton’s work in these areas was either through his students or through his provision of isotope stratigraphy to areas of interest to his palaeontological colleagues.

correlation by fossils holds a key position in correlation between cores and age determi-nation. an often unresolved question (in all biostratigraphy) is whether the appearance or disappearance from a stratigraphic section is globally or regionally synchronous. Shackleton’s isotope stratigraphy and tuned ages allowed these questions to be addressed. Several papers established the global synchroneity of microfossil datums in coccoliths, diatoms, radiolarians, and planktonic and benthic foraminifera; and in one case a diachronous extinction was dem-onstrated (12, 17–19, 21, 23, 24, 45, 53, 61). More important than specific contributions is his general approach, which, with modern cyclostratigraphy (stratigraphy related to Milankovitch cyclicity), many are now following. accurate age models permitted an inference of accumu-lation rates and an approach to palaeoproductivity that was then related to varying insolation and related environmental variables. the isotopic ratios in foraminifera are partly determined by the depth (temperature) at which they lived, a feature that coxall and colleagues (61), for example, used to reveal changes in the mode of life in a single evolutionary lineage.

Shackleton relied on colleagues expert in palaeomagnetic measurements from early in his career, because he recognized the power of magnetic reversal stratigraphy for global correla-tion. together with biostratigraphy it was the most natural accompaniment to isotopic work. among his most important early papers were those with the palaeomagnetist Neil opdyke (5, 14, 16). a later development was estimation of the past intensity of the earth’s magnetic field, an area in which he was again in the vanguard with French palaeomagnetists laure Meynadier and Jean-Pierre Valet in producing well-dated histories of intensity (44, 51). the intensity is of value in both correlation and dating of cores and in understanding the variation of cosmogenically produced isotopes, especially 14c and 10Be.

a change of MInd?

Bill ruddiman has pointed out several aspects of Nick’s scientific style and modus operandi. once having chosen a new problem to explore, he forged well-chosen alliances to figure out




which sediment core was best for his purposes. invariably he made the optimal decision and wrote the definitive paper. he also liked to take strong positions in his talks, often proposing that a particular factor was primary in a causal sense and that others could be ignored. over the years, his designations of which factors were ‘primary’ versus ‘secondary’ sometimes varied, because he preferred stimulating debate more than holding to a strict consistency.

a good example of this is his paper, ‘the hundred thousand-year ice age cycle identified and found to lag temperature, carbon dioxide and orbital eccentricity’, published in Science in 2000 (62): it is unusual in showing no new data but is one of Shackleton’s most interesting and daring contributions. having shown early in his career that the ice-volume component of the marine oxygen isotope records is dominant over temperature, there had been no way of knowing precisely what the contributions are.

By comparing ice-core and deep-sea records in a complex manner, he was able to separate the two contributions and showed that the ice-volume component lags behind (it responds with a delay) the changes in co2. in other words, changes in the ice sheets do not cause changes in atmospheric co2. Shackleton’s analysis showed the reverse: co2 had a major role in causing the changes from glacial to interglacial conditions. this is an extremely profound analysis with potentially very important ramifications for our future climate. this paper also provided an interesting glimpse into the way in which Shackleton addressed problems, described by tom crowley in his obituary in Eos, Transactions, American Geophysical Union as being characterized by a penetrating level of analysis and an almost legalistic precision of phrasing.

shackleton and ocean drIllIng

the wellspring of much of Shackleton’s career lay in data obtained from oceanic core sam-ples. Standard piston cores available in the late 1960s were rarely longer than 20 m, and most extended back in time no more than several hundred thousand years, unless the sedimentation rate was very slow. the advent of deep ocean drilling, which started in earnest in 1968, pro-vided a far longer time window, one that he exploited with striking effect. Nick Shackleton was a prolific contributor to the Deep Sea Drilling Project (DSDP) and to its successor, the ocean Drilling Program. From 1972 to 1998 he contributed 53 papers and data reports to the volumes of those programmes, more than anyone other than the projects’ staff. he sailed on four two-month drilling voyages on DV Glomar Challenger and DV JOIDES Resolution (figure 7) in the North and South atlantic and Pacific (legs 74, 138, 154 (chief scientist) and 171B). he served as a member of both projects’ ocean history Panels between 1975 and 1991 (chairman 1989–91). he was primus inter pares of those responsible for providing one of the three major pillars, that of ocean environmental history, on which the international drilling programmes rest (the others being tectonics and crustal petrology). his efforts over the years gave a significant measure of the justification that the Uk Natural environment research council needed to pay the Uk subscription to join and remain a member of the drilling consortium.

Many of Shackleton’s seminal ideas were developed with collaborators in the drilling pro-grammes, and often they first saw the light of day in their initial reports and results volumes. For example, the Shackleton and kennett work in Nature (13) on the development of antarctic glaciation was presaged by their papers the year before in volume 24 of the DSDP (8, 9); and similarly with North atlantic climate and glaciation in Nature (31) and DSDP volume 81 in




1984 (30). his work on the development of orbitally tuned time scales was also premiered in these volumes: that for the late Neogene in 1995 (50) and for the oligocene in 1997 (54), along with or ahead of their appearance in the mainstream literature (48, 56).

the working environment on a ship acts as a sort of incubator with close contact between colleagues for months on end. in this environment they developed the methods of multiple overlapping coring to construct the complete sequences needed for the reliable spectral analy-sis and orbital tuning of long records (42, 43, 47). the staff of a drilling leg includes special-ists in all fields relevant to palaeoceanography. From the samples obtained, collaborations

(a)

(b)

Figure 7. (a) the original drilling ship, rV Glomar Challenger, 1968–89. (b) the successor ship, rV JOIDES Resolution, after refit in 2003. (credit: ioDP/taMU.) (online version in colour.)




established and projects initiated flowed work on isotope history from the Pleistocene down to the oligocene (0–30 Ma ago), isotope studies in squeezed pore waters, fossil abundance variations and responses of biota to orbital forcing, isotope variations and planktonic foramini-fer depth habitats, chemical composition of sediments and productivity variations, sediment fluxes based on orbitally tuned time scales, and determinations of relative geomagnetic inten-sity—a small selection from a huge output. all this was underpinned by meticulous attention to stratigraphic correlation and the establishment of precise chronology. his contribution to virtually all aspects of Quaternary research was recognized by his being elected President of iNQUa (the international Union for Quaternary research) from 1999 to 2003.

the godwIn laBoratory, MusIc and the postage staMp

The Godwin Laboratorythe Godwin laboratory on Free School lane was a Mecca for visitors both from earth Sciences across Downing Street and from outside cambridge. he was supportive of and

Figure 8. annual Godwin laboratory photograph from 2003–04. Nick Shackleton is fourth from the left in the front row. the authors are fourth from the left in the second row from the front (i. N.Mcc.) and sixth from the left in the front row (h. e.). the full list is (from left to right): front row, Patrizia Ferretti, Pallavi Jha, Maryline Vautravers, Nick Shackleton, tjeerd van andel, harry elderfield, linda Booth, Jimin Yu; second row, lucia de abreu, isabel cacho, Mike hall, Nick Mccave, caroline Daunt, Mervyn Greaves, James Partington; third row, thorsten keifer, James rolfe, katcha rinne, helen houghton; back row, Simon crowhurst, John Waterhouse, roy Switsur, Steve Barker, luke Skinner. absent were aradhna tripati, Fiona hall, christina De la rocha and chronis tzedakis. (online version in colour.)




helpful to younger scientists worldwide, and gave freely of his time to discuss their results. in his trademark sandals, he was unfailingly polite and helpful with the many who sought him out, and his cambridge laboratory became something of a pilgrimage site. he let his stu-dents and an entire community share in his brilliance and vision. andy Gale, in his Guardian obituary, said that to know that Nick Shackleton liked your work and supported your efforts provided a much-needed boost to the self-confidence of researchers. Shackleton’s labora-tory became a factory for stable-isotope analyses with a huge annual output that could not be beaten by other laboratories. this was to a large degree due to Mike hall, his laboratory manager. each year a Godwin laboratory photograph was taken (figure 8 is an example), the participation being in part a movable feast, including visitors who happened to be present and students and postdoctoral workers of i. N.Mcc. and h. e. on one occasion, Nick (Shackleton) was absent, so a space was left for him and he stood on the spot on his return and was inserted into the photograph electronically.

Musicas well as his many scientific accomplishments, Shackleton excelled in another area, that of music, which was almost as important to him as science. he was a very accomplished clarinet player and an internationally renowned collector and scholar of the instrument. in cambridge he lectured and supervised in the Faculty of Music on the physics and acoustics of music. Shackleton contributed articles to both editions of The new Grove dictionary of music and musicians (1980 and 2001) as well as to The Cambridge companion to the clarinet (ed. colin lawson) and journals such as Galpin Society Journal. he also reviewed books on musical instruments, and contributed notes for lP and cD recordings.

Shackleton amassed what is almost certainly the largest collection of clarinets in the world. When he bequeathed it to the University of edinburgh his collection numbered over 800 instruments, including 817 clarinets and basset horns. he liked to remark, somewhat disin-genuously (having had no children), that all this could be done on just a university lecturer’s salary.

Quaternary research was the major interest in his life; music was a very close second. in his words: ‘Both music and science are for me intensely human activities, and both have found me innumerable friends.’ Shackleton’s love of music was known to his science colleagues, especially through his participation in the ‘palaeomusicology’ concerts that were one of the highlights of the international Paleoceanography conferences.

an appreciation of Nick as a musician is given here by ingrid elizabeth Pearson, Nick’s partner at the time of his death, and herself a scholar and clarinettist:

only when Nick (Nikki, as he was known by those closest to him) Shackleton was knighted in 1998, did his musician acquaintances realise just how distinguished a scientist he was! those from outside the Uk got to know Nick through his comprehensive article on the clarinet in The new Grove dictionary of music and musicians, published under the editorship of the late Stanley Sadie, in 1980. as an undergraduate at the University of Sydney in the early 1990s, i received a personal letter from Nick answering a question about an aspect of clarinet history. i was so excited i ran the length of the campus to show the letter to my lecturers! Subsequent correspondence included an invitation to stay with Nick, and Vivien, during my first visit to the Uk in late 1992. thanks partly to Nick’s generos-ity in sharing both his collection and vast array of supporting documentary materials as well as his very real interest in my curiosity about an aspect of the clarinet’s history, i returned to the Uk a few years later to undertake doctoral study in that area. i was just one of many younger people fortunate enough to have been nurtured by Nick, in either his musical or his scientific life.




this nurturing was to have a particularly profound and timely effect on the historical perform-ance movement, through Nick’s friendship with the brilliant young cambridge woodwind-instru-ment maker Daniel Bangham. Nick and Daniel first met in 1979, and by the early 1980s Daniel’s workshop was making superb copies of many of Nick’s instruments. other makers soon followed suit, including those from France, canada, the Netherlands and the USa. these instruments can be heard on recordings and are still in use among players today. Nick was also happy to loan instruments from his collection, in playing condition, for concerts and recordings. and many of the Shackleton instruments were loaned to other museums, most recently to the Berlin Musical instrument Museum for the 2004/5 exhibition celebrating 300 years of the clarinet.

evidence of Nick’s standing in the musical community was the number of professional musi-cians he counted among his personal friends. they were regular visitors to his home in tenison avenue, cambridge, not only to marvel at the treasures contained in the clarinet room (figure 9), but to engage in musical, intellectual and social banter. Nick knew most of the clarinettists in orchestras across the world. if he didn’t, he’d take the opportunity to meet them after the concert, if possible.

Figure 9. ‘Nikki’ in his clarinet room. (Photograph taken by ingrid Pearson; reproduced with permission.) (online version in colour.)




Nick was an avid concert-goer, with wide-ranging and eclectic musical taste. this was also reflected in his personal collection of 78s, lPs and cDs, which included music from ethiopia, Georgia and india alongside the staples of Western art music, particularly works for wind instru-ments. Music by Leoš Janáček, Richard Strauss and Igor Stravinsky were his favourites. Nick is, in fact, one of the basset horn players on The Music Party’s recording of Mozart’s Serenade in B♭, k361/370a, the so-called ‘13-instrument Serenade’, an early period-instrument documentation of the work. in this recording he plays on an instrument by raymund Griesbacher from his collec-tion. he also appears in a recording of music by Georg Druschetzky, performing on a clarinet by kaspar tauber from his collection.

Nick approached music with the insight, determination and diligence that marked his sci-entific work. he had practised his clarinets regularly since the days as bass clarinettist in the orchestra of the cambridge University Music Society, and earlier in the army. latterly, Nick enjoyed playing chamber music with his cambridge friends most weeks. in the words of Nick’s friend, the late William Waterhouse, the eminent bassoonist and scholar, ‘in Nick, musicians had, for the first time, the benefit of a brilliant researcher applying the rigour of a scientist to our problems’.

The stampWhy the stamp? in 2010 the royal Society celebrated 350 years of science since its foundation in 1660 by the royal Mail’s issuing a set of ten stamps of notable members of the Fellowship. one of the ten was of Nick Shackleton (figure 10). the others were charles Babbage, robert Boyle, Benjamin Franklin, Dorothy hodgkin, edward Jenner, Joseph lister, isaac Newton, ernest rutherford and alfred russell Wallace: a talented group!

Nick Shackleton died of leukaemia at a relatively young age. he was first diagnosed with non-hodgkin’s lymphoma in 2001. tragically, an element of the chemotherapy manifested itself in late 2005 as a leukaemic complication, and it was this that led to Shackleton’s untimely death. he had been retired for about one year. he explained to many who said they expected he would carry on as usual after retirement that, to the contrary, he would have more time for his music. his retirement coincided with the physical move of the Godwin laboratory to space within the main site of the earth Sciences Department. his mass spec-trometers were moved across Downing Street (and still work well) and a ‘bolt hole’ office for him was included in the plans for the newly located Godwin laboratory. Sadly, he occu-pied it only for a short time.

Figure 10. the first-class Uk postage stamp. (copyright © 2010 royal Mail Group ltd)(online version in colour.)




awards and honours

1985 Fellow of the royal Society Shepard Medal for Marine Geology, Society for Sedimentary Geology, USa carus Medal, Deutsche akademie für Naturforscher ‘leopoldina’1987 lyell Medal, Geological Society of london1988 Founding Member, academia europaea1990 Fellow, american Geophysical Union huntsman Medal for Marine Sciences, Bedford institute of oceanography, canada1995 crafoord Prize, royal Swedish academy of Sciences1996 honorary Doctor of laws, Dalhousie University, canada Wollaston Medal, Geological Society of london1997 honorary Doctor of Philosophy, Stockholm University, Sweden1998 knighthood, for services to the earth Sciences1999 Milankovitch Medal, european Geophysical Society2000 Foreign associate, US National academy of Sciences2001 Foreign Member, royal Netherlands Society of arts and Sciences2002 honorary Doctorate, Geology, University of Padua, italy ewing Medal, american Geophysical Union2003 honorary Member, european Union of Geosciences Urey Medal, european association of Geochemistry royal Medal, royal Society2004 Vetlesen Prize, columbia University2005 Founders Medal, royal Geographical Society Blue Planet Prize, asahi Glass Foundation, Japan

acknowledgeMents

obituaries of Nick Shackleton appeared anonymously in The Times, by tom crowley in Eos, Transactions, American Geophysical Union, by andy Gale in The Guardian, by Gerald haug and larry Peterson in Nature, by harry elderfield in The Independent, by Nadine Brozin in The New York Times, by Jim hayes in Quaternary Science Reviews, by Bill ruddiman in Science and by Nick Mccave in Oxford dictionary of national biography. We have quoted directly or indirectly from their words, and this has helped us in writing this account. We also thank heiko Pälike for his comments on sections of the manuscript.

the frontispiece photograph was taken in 2004 by the Godwin laboratory, cambridge, Uk, and is reproduced with permission. (online version in colour.)

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(15) 1977 carbon-13 in Uvigerina: tropical rainforest history and the equatorial Pacific carbonate dissolution cycles. in The fate of fossil fuel CO2 in the oceans (ed. N. r. andersen & a. Malahoff), pp. 401–427. New York: Plenum Press.

(16) (With N. D. opdyke) oxygen isotope and palaeomagnetic evidence for early Northern hemisphere glaciation. Nature 270, 216–219.

(17) (With h. r. thierstein, k. r. Geitzenauer & B. Molfino) Global synchroneity of late Quaternary coc-colith datum levels: validation by oxygen isotopes. Geology 5, 400–404.

(18) 1978 (With l. h. Burckle & D. B. clarke) isochronous last-abundant-appearance datum (laaD) of the diatom Hemidiscus karstenii in the sub-antarctic. Geology 6, 243–246.

(19) (With t. B. kellogg & J. c. Duplessy) Planktonic foraminiferal and oxygen isotopic stratigraphy and paleoclimatology of Norwegian Sea deep-sea cores. Boreas 7, 61–73.

(20) 1979 (With l. e. heusser) Direct marine-continental correlation: 150,000-year oxygen isotope-pollen record from the North Pacific. Science 204, 837–839.

(21) (With P. r. thompson, a. W. h. Be & J.-c. Duplessy) Disappearance of pink-pigmented Globigerinoides ruber at 120,000 yr Bp in the indian and Pacific oceans. Nature 280, 554–557.

(22) 1981 (With cliMaP Project Members) Seasonal reconstructions of the earth’s surface at the last glacial maximum. in Geological Society of America. Map and Chart Series no. Mc-36 (ed. r. cline). Boulder, co: Geological Society of america.

(23) 1983 (With J. Backman & l. tauxe) Quantitative nannofossil correlation to open ocean deep-sea sections from Plio-Pleistocene boundary at Vrica, italy. Nature 304, 156–158.




(24) (With J. Backman) Quantitative biochronology of Pliocene and early Pleistocene nannofossils from the atlantic, indian and Pacific oceans. Mar. Micropaleontol. 8, 141–170.

(25) (With M. a. hall, J. line & S. cang) carbon isotope data in core V19–30 confirm reduced carbon dioxide concentration in the ice age atmosphere. Nature 306, 319–322.

(26) (With J. imbrie & M. a. hall) oxygen and carbon isotope record of east Pacific core V19-30: implica-tions for the formation of deep water in the late Pleistocene North atlantic. Earth Planet. Sci. Lett. 65, 233–244.

(27) 1984 (With J. c. Duplessy) carbon-13 in the world ocean during the last interglaciation and the penultimate glacial maximum. reevaluation of the possible biosphere response to the earth’s climatic changes. Prog. Biometeorol. 3, 48–54.

(28) (With J.-c. Duplessy, r. k. Matthews, W. Prell, W. F. ruddiman, M. caralp & c. h. hendy) 13c record of benthic foraminifera in the last interglacial ocean: implications for the carbon cycle and the global deep water circulation. Quat. Res. 21, 225–243.

(29) (With J. imbrie, J. D. hays, D. G. Martinson, a. Mcintyre, a. c. Mix, J. J. Morley, N. G. Pisias & W. l. Prell) the orbital theory of Pleistocene climate: support from a revised chronology of the marine δ18o record. in Milankovitch and Climate, Part 1 (ed. a. l. Berger et al.), pp. 269–305. Dordrecht: D. reidel.

(30) (With h. B. Zimmerman, J. Backman, D. V. kent, J. G. Baldauf, a. J. kaltenback & a. c. Morton) history of Plio-Pleistocene climate in the northeastern atlantic, Deep-Sea Drilling Project hole 552a. Init. Rep. DSDP 81, 861–876.

(31) (With J. Backman, h. Zimmerman, D. V. kent, M. a. hall, D. G. roberts, D. Schnitker, J. G. Baldauf, a. Desprairies, r. homrighausen, P. huddlestun, J. B. keene, a. J. kaltenback, k. a. o. krumsiek, a. c. Morton, J. W. Murray & J. Westberg-Smith) oxygen isotope calibration of the onset of ice-raft-ing and history of glaciation in the North atlantic region. Nature 307, 620–623.

(32) (With a. G. Wintle & J. P. lautridou) thermoluminescence dating of periods of loess deposition and soil formation in Normandy. Nature 310, 491–493.

(33) 1985 (With J.-c. Duplessy) response of global deep-water circulation to the earth’s climatic change 135,000–107,000 years ago. Nature 316, 500–507.

(34) 1986 (With J. chappell) oxygen isotopes and sea level. Nature 324, 137–140.(35) 1987 (With D. G. Martinson, N. G. Pisias, J. D. hays, J. imbrie & t. c. Moore Jr) age dating and the orbital

theory of the ice ages: development of a high-resolution 0 to 300,000-year chronostratigraphy. Quat. Res. 27, 1–30.

(36) 1988 (With W. B. Curry, J.-C. Duplessy & L. D. Labeyrie) Changes in the distribution of δ13c of deep water ΣCO2 between the last glaciation and the holocene. Paleoceanography 3, 317–341.

(37) (With J.-c. Duplessy, r. G. Fairbanks, l. D. labeyrie, D. oppo & N. kallel) Deepwater source variations during the last climatic cycle and their impact on the global deepwater circulation. Paleoceanography 3, 343–360.

(38) (With J.-c. Duplessy, M. arnold, P. Maurice, M. a. hall & J. cartlidge) radiocarbon age of last glacial Pacific deep water. Nature 335, 708–711.

(39) 1989 (With S. A. Hovan, D. K. Rea & N. G. Pisias) A direct link between the China loess and marine δ18o records: aeolian flux to the north Pacific. Nature 340, 296–298.

(40) (With M. a. hall) Stable isotope history of the Pleistocene at oDP Site 677. Proc. ODP Scient. Results 111, 295–316.

(41) 1990 (With a. Berger & W. r. Peltier) an alternative astronomical calibration of the lower Pleistocene timescale based on oDP Site 677. Trans. R. Soc. Edinb. Earth Sci. 81, 251–261.

(42) 1992 (With l. Mayer, N. Pisias, t. hagelberg, N. Pisias & Shipboard Party) Development of composite depth sections for Sites 844 through 854. Proc. ODP Init. Rep. 138, 79–85.

(43) (With Shipboard Party) Sedimentation rates: towards a GraPe density stratigraphy for leg 138 car-bonate sections. Proc. ODP Init. Rep. 138, 87–91.

(44) (With l. Meynadier, J.-P. Valet, r. Weeks & V. lee hagee) relative geomagnetic intensity of the field during the last 140 ka. Earth Planet. Sci. Lett. 114, 39–57.

(45) 1993 (With t. c. Moore Jr & N. G. Pisias) Paleoceanography and the diachrony of radiolarian events in the eastern equatorial Pacific. Paleoceanography 8, 567–586.




(46) 1994 (With F. c. Bassinot, l. D. labeyrie, e. Vincent, X. Quidelleur & Y. lancelot) the astronomical theory of climate and the age of the Brunhes/Matuyama magnetic reversal. Earth Planet. Sci. Lett. 126, 91–108.

(47) 1995 (With W. a. Berggren, F. J. hilgen, c. G. langereis, D. V. kent, J. D. obradovich, i. raffi & M. e. raymo) late Neogene chronology: new perspectives in high-resolution stratigraphy. Bull. Geol. Soc. Am. 107, 1272–1287.

(48) (With t. k. hagelberg, N. G. Pisias, a. c. Mix & S. harris) refinement of a high-resolution, continu-ous sedimentary section for the study of equatorial Pacific paleoceanography: leg 138. Proc. ODP Scient. Results 138, 31–46.

(49) (With M. a. Maslin & U. Pflaumann) Surface water temperature, salinity, and density changes in the northeast atlantic during the last 45,000 years: heinrich events, deep water formation and climatic rebounds. Paleoceanography 10, 527–544.

(50) (With S. crowhurst, t. hagelberg, N. Pisias & D. a. Schneider) a new late Neogene time scale: application to oDP leg 138 sites. Proc. ODP Scient. Results 138, 73–101.

(51) (With l. Meynadier & J.-P. Valet) relative geomagnetic intensity during the last 4 million years from the equatorial Pacific. Proc. ODP Scient. Results 138, 779–796.

(52) 1996 (With l. tauxe, t. herbert & Y. S. kok) astronomical calibration of the Matuyama Brunhes Boundary: consequences for magnetic remanence acquisition in marine carbonates and the asian loess sequences. Earth Planet. Sci. Lett. 140, 133–146.

(53) (With e. thomas) the Paleocene–eocene benthic foraminiferal extinction and stable isotope anoma-lies. in Correlation of the early Paleogene in northwestern Europe (Geological Society Special Publication 101) (ed. r. W. o’B. knox, r. M. corfield & r. e. Dunnay), pp. 401–441. london: Geological Society.

(54) 1997 (With S. crowhurst) Sediment fluxes based on an orbitally tuned time scale 5 Ma to 14 Ma, site 926. Proc. ODP Scient. Results 154, 69–82.

(55) (With P. c. tzedakis, V. andrieu, J.-l. de Beaulieu, S. crowhurst, M. Follieri, h. hooghiemstra, D. Magri, M. reille, l. Sadori & t. a. Wijmstra) comparison of terrestrial and marine records of chang-ing climate of the last 500,000 years. Earth Planet. Sci. Lett. 150, 171–176.

(56) 1999 (With a. S. Gale, J. r. Young, S. J. crowhurst & D. S. Wray) orbital tuning of cenomanian marly chalk successions: towards a Milankovitch timescale for the late cretaceous. Proc. R. Soc. Lond. a 357, 1815–1829.

(57) (With l. P. Zhou) Misleading positions of geomagnetic reversal boundaries in eurasian loess and implications for correlation between continental and marine sedimentary sequences. Earth Planet. Sci. Lett. 168, 117–130.

(58) 2000 (With h. Pälike) constraints on astronomical parameters from the geological record for the last 25 Myr. Earth Planet. Sci. Lett. 182, 1–14.

(59) (With i. cacho, J. o. Grimalt, F. J. Sierro & M. canals) evidence for enhanced Mediterranean thermo-haline circulation during rapid climatic coolings. Earth Planet. Sci. Lett. 83, 417–429.

(60) (With M. r. chapman & J.-c. Duplessy) Sea surface temperature variability during the last gla-cial–interglacial cycle: assessing the magnitude and pattern of climate change in the North atlantic. Palaeogeog. Palaeoclimatol. Palaeoecol. 157, 1–25.

(61) (With h. k. coxall, P. N. Pearson & M. a. hall) hantkeninid depth adaptation: an evolving life strat-egy in a changing ocean. Geology 28, 87–90.

(62) the 100,000-year ice-age cycle identified and found to lag temperature, carbon dioxide and orbital eccentricity. Science 289, 1897–1902.

(63) (With M. a. hall & e. Vincent) Phase relationships between millennial scale events 64,000 to 24,000 years ago. Paleoceanography 15, 565–569.

(64) 2001 (With J. c. Zachos, J. S. revenaugh, h. Pälike & B. P. Flower) climate response to orbital forcing across the oligocene–Miocene boundary. Science 292, 274–278.

(65) 2004 (With h. Pälike & J. laskar) Geological constraints on the chaotic diffusion of the Solar System. Geology 32, 929–932.

(66) (With r. G. Fairbanks, t.-c. chiu & F. Parrenin) absolute calibration of the Greenland time scale: implications for Antarctic time scales and for Δ14c. Quat. Sci. Rev. 23, 1513–1522.


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Sir Nicholas John Shackleton. 23 June 1937 −− 24 January 2006three children of robert Millner...

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