Postglacialsea-level history of Edge6ya and,B arents6v a. easternSvalbard
STEIN BONDEVIK, JAN MANGERUD, LARS RONNERTand oTTo SALVIGSEN
Bondevik' S Mangcrud. . J . Ronnert., L. & Salvigsen,O. 1995: Postglacial sealevcl historv ol Edgcoya polar and Barentsoya, easrern Svalbard. Reseurch14 f2l. 153 iUO. Four relative sea-lcvel curves from Edgeoya and Barentsoya are constructed bascd on ll1 radiocarbon agc dcterminations on carefully selected and levellcd samples in raised beaches. mostly driftwood cmbeddcd in beach gravel All thc dates, covcring the period from the deglaciation to the prescnt, arc calibrated to calendar years, and the sea-level curves are delined by fitting the data with a lcast square rcgressi{rncurve. The dates are internally very consistent. and the rcsults are some of the most precisc sea-lerielcurves trom the Arctic. The four curves are quite similar. and from the marine limit at 85 90 m a.s.l. thcy show a rapid emergence (ca 40 mm/year). formed about 11,000cal yrs Bp (-10,000r1C yrs Bp). A minimum rate of emcrgencc close to 8000 cal years ago is explained by a decreascd rate in isostatic uplift parallel with a sustained rate of eustatrc sca-levcl rise During the last 7000 cal vears, the emergence rate has decreasedlinearlv. The uplift ratcs have been slightly higher on southern Edgeoya than furrher norrh during rhc lasr 7t)o0 ycars. By comparing the sea-lcvel curves from Sloroya (ca 270 km to the north) and Hopcn (ca 150 km to rhc south). wc suggest that a mcmory of an earlier and larger glacio-isostaticdownwarping in the southern tsarents Sea is deteclcd in the sea-level curves from Hopen and southern Edgeoya. stein Bondettik and Jan Mangerutr, Departnent oJ Geolog\', IJnipersiu-of Bergen, Ail?gt rl, N-5007Bergen, Noruat, l'arsRonnert DepartmeilofGeolog,-,LlniuersitofGdteborgfChatmersLlniiersitl-of7echnolctgy, S-11296Gdreborg. Sweden" otto Saluigsen,Norsk Polorinstitutt, P.(). Box 5072Mujorstua, N4301 oslo.
Introduction Driftwood is frequent on and within the raised beaches in eastern Svalbard (Salvigsen 197g, The pattern of glacio-isostatic uplift has been a 1981)and is extremely well preserveddue to the classical tool for reconstructing the last glacial dry, cold climate. On Edge0ya and Barents0ya maximum ice sheetsin the Arctic of both North raisedbeaches are common in a number of foie- America (e.g. Andrews 1970; Blake 1970) and lands and outer valley mouths up to 90 m a.s.l. Europe (e.g. Schytt et al. 1968).ln recent years These provide a high resolution record for the a more sophisticatedgeophysical modelling has constructron of sea-level curves. been applied to sea-level data, both to reveal the Wood, fed by the large rivers of Siberia into glacial history and to study the structure of the the Arctic Ocean, is caught in drifting ice and earth'sinterior. For the Svalbardand BarentsSea transportedtowards Svalbardat an averagespeed areas, this was recently done by Elverhoi et al. of 600 km/year (Haggblom 1982; Eggertsson (1993). Breuer & Wolf (1995) and Lambeck 1994).To cover a distanceof 3000 km, a driftwood (1995). Thus the importance of the geological log needs more than three years for the passage work has moved more to primary observational from Siberia to Svalbard.Because wood absorbs data and the geological interpretation of the field water. logs can float in the ocean at maximum l_ relationships.Accordingly the aim of this study 1.5 years and therefore no driftwood would reach is to determine as accurately as possible the elev- Svalbard from Siberia drifting on an ice-free Arc- atron and age for the relative sea level by means tic Ocean (Haggblom 1982). Also some wood of extensive and careful Iield work and samole probably originated from European Russia. treatment.Edgeoya and Barentsoyarepresenied which is closer.The strandingof driftwood on the a lacune in our previous knowledge of the uplift shores in eastern Svalbard takes place mainlv of Svalbard (see compilation in Forman 1990).It during the summer period when the coastalwaters was therefore important to cover this area with are ice free. reliable sea-level data. The sea-levelcurves con- Emergence of land relative to the sea is a pro_ structed are some of the most accurate sea-level cess measured in mm/year. Since a laC year has curves available from the Arctic. varied in length through the Holocene, rates siven 15.1 S. Bontlet,ik ct ul
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77"30' Postglacial sea-leL)elhistor,v of Edge6,vaand Barentstvo, eosternSualhurd 155
WHALEBOI.JE I
Fig. 2. Relation betwccn sea levcl (mcan tidc) and [$F:'l 6,ou"; sea level indicators sanu (driftwood. whalcbonc rnd llll l LIFEPOSITION molluscs).
in rrC yearswill be imprecise.We have therefore determinedwith an altimeter. In the field we used calibratedthe raCdates to calendaryears by using the local driftwood limit as referencepoint. This the calibration program of Stuiver & Reimer was determinedto be 3.2.2.8 and 1.6m above (1993).This calibrationprogram, basedon den- mean tide level at Kapp Ziehen, Humla and Dis- drochronology.will probably not changemuch in kobukta. respectively (Fig. 2). All altitudes of the future for the time period consideredhere samplesand shorelinesare corrcctedand refer to (the last 10.000 '+Clyears). Both '{C years and mean-tide level. The locations of samples are calibratedyeitrs are given in the tables(Tables 1- shown on aerial photographs(Figs. 7 10). 4). Wood and bones partly or totallv embeddedin Samplesfor radiocarbondating three complete beach gravel were preferred instead of samples sea-levelcurves were collected at Kapp Ziehcn restingon the surface.In intervalswhere embed- on Barentsoya and Flumla and Diskobukta on ded samples were not found. we preferrcd to Edgeoya(Fig. l). In additionwe collectedsome sample large logs and bones (2 -5m length) samples from higher elevations to complete a located on wide terraces as these were unlikely l]C well-datedscl-lcrel curvc for the last 9UU() to have been moved after primary deposition. yearsfrom the southern part of Edgeoya (Knape However, most of the dated samples were 197r). anchoredin beach gravel and often coveredwith A prcliminary sea-levclcurve from Humla has a silt-rich surfacesoil. (Fig. '1.Tables I 4). becn published (Mangerud et al. 1992b),and An effort was made to date only the outer a more detailed description of both dated and wood from driftwood logs. For most logs we undatcd samplesfrom Humla and Diskobukta is sampled the whole cross section in the field and givenin Bondevik( 1993).ln thispaper we present then prepareda pieceof the outer wood for dating fbur completc sca-lcvel curves from the area, in thc laboratory. The densestpart of the bone based on more than 80 radiocarbon age deter- was collected, and in the laboratory it was cut minations. into cubes in order to examine any porous bone for extraneousmatter. as recommendedby Dyke et al. (1991).Most of the datedbones were com- pletely dense with a greasy lustre on the sawed Methods surface.
Fieldwork Radiocarbon dutes tutd ace calibrutiort All sample and paleoshoreline(terraces. beach ridges) altitudeswere determined by preciselev- The radiocarbon dates are reported as rec- elling. except firr the samplescollected in Dian- ommended by Stuiver & Polach (1977) and adalcnon southernEdgeoya (Fig. l). whichwere include a correction for isotopic fractionation to
tig. /. Kcl map of thc invcstigatcdrrcas on Barcntsrtvaand I:dgernl. Cilacicrsarc shadcd. Insct nap ol Svrlbrrtl 156 S. Bondeuik et al.
make them comparableto the driftwood samples of -24.5Voo613C, we have added45 years. All dates were calibrated to calendaryears by using the calibrationprogram CALIB ver 3.0.3 (Stuiver & Reimer 1993) and denoted as cal yrs sp in the text. The datings are cited in the text and figuresas the interval betweenthe maximum age and the minimum age (one o) in calibrated yearsbefore present(1950), given as column A and D in Tables 1-4.
Determinationof wood species Nearly all the dated driftwood samples were identified to genus or specieslevel (Tables 1, 2 paulssen Frg. 3. Driftwood logs embedded in beach gravel 31.9ma.s.i. and 3) under the microscopeby Leif M. in Humla. Another log having similar stratigraphic position at the University in Oslo (Kapp Ziehen) and found close to these (1-2 m) was dated to 7220-7090 cal yrs Bp Olafur Eggertsson at the University of Lund (sample 88-508, Table 2, Fig. 8). The boundary between beach (Humla and Diskobukta). In addition. paulssen gravel just and the silt-rich surface soil lies above the log to the studied the left of the trowel. The trowel is ca 25 cm long. wood after carbonisation. We are aware that identification of Picea and Larix is problematic and sometimescontroversial. Here -25%o 6r3Con the PDB scale.A reservoir ageof we simply cite the results reported to us. 440 years has been subtracted in the reported raC ages (Tables 1-4) for all samplesthat have Amino acid measurements obtained their carbon from seawater (shellsand whalebones) (Mangerud & Gulliksen1975). The Six shellfragments from the assumedmarine limit samples have been dated at the laboratory in terrace in Humla were analysed at the Bergen Trondheim (prefix T-, on samples), and at the laboratory (prefix BAL-). In this paper we report Iaboratory in Lund (prefix Lu-). Sampleswith the epimerisation of isoleucine to alloisoleucine prefix TUa- are accelerator mass spectrometry for the total fraction, expressedas D/L ratios (AMS) datings. The target was prepared in (by some labetled AIle/Ile) and the D/L ratios Trondheim, and the AMS measurementsper- measured for the free fraction. All fraements formed in Uppsala. are Mya truncata or Hiatella arctica, whic-hhave The samplescited from Knape (1971) were approximatelysimilar epimerisationrates (Miller dated at the laboratory in Stockholm (prefix re82). St-). Initially, these dateswere not correctedfor isotopic fractionation (Magnus Hedberg, oral Relationbetween the mean comm. 1994). We have corrected the dates on tide level whale bonesto -25%od3C by assuminga value and sea-levelindicators -16.4%o of for the bones,which is a meanvalue Our aim was to constructprecise and well-docu, for Arctic whale bones dated at the laboratory mented sea-levelcurves. A pre-requisitefor this in Trondheim (Gulliksen 1980). The Stockholm is to understand the relationship between the dates on driftwood are not corrected for frac- presentsea level andindicators of paleo-sea-levels tionation, but any errors for this reasonwoirld be suchas shore sedimentsand the datable material negligible. within or on top of shore sediments. -24.5 -+ A mean value of 0.8%o 613C was On the present shore a gravel beach ridge is obtained from 28 driftwood samplesfrom Humla formed during heavy surf and storms. The crest and Diskobukta and usedfor the agecalculations of the ridge is found I to 2m above high-tide (S. Gulliksen, Laboratory for Radiological Dat- level; its altitude is determined by wave height ing in Trondheim, written comm. 1994). The during storms. Wave energy reaching the shore -27.2%o laboratory in Lund assumesa value of. is the major factor controlling the development 613Cfor all wood samplesbefore correction. To of the beach (Reineck & Singh 1980).On gently Postglacial sea-leuel history of Edge4ya and Barentsqya, eastern sualbard 157
sloping shores, as are found on EdgeOya and Whales usually float after they die and while Barents6ya, the waves break a considerable dis- they decompose. Their cadaver may float ashore tance offshore producing a beach ridge having and become stranded (Dyke et al. 1991). Also a low relief. Driftwood and other flotsam are old, injured or disoriented whales may beach commonly found on top of the ridge (Figs. 2 and themselves in the near-shore zone. Individual 3). bones or the entire carcasswill normally be rewor- A beach ridge formed during an extreme storm ked by waves and thrown up to the driftwood will destroy lower ridges on the shore. This prob- limit. Thus, bones from one whale may be spread ably means that the elevated beach ridges were over a larger area. However, Blake (1975) argued formed during the largest storm within a time that because of their weight and size, whales period of 20-50 years for the oldest beaches(rapid would more likely be deposited in shallow water regression, 2040mmfyear) and 500-1000 years than thrown up onto the beach ridge by storm for the youngest (slow regression, 0.5-2 mm/ waves. In Smelledalen (Figs. 1 and 9), we found year), and this is the reason why the shorelines three bone heaps on the surface 25 m a.s.l., each often depict a staircase from the present shore containing most of the bones of an individual and upward (e.g. (Fletcher Fig. 7) III et al. 1993). whale; at another site we found nearly a whole Driftwood is the most reliable indicator for row of a dorsal vertebra embedded in beach sravel paleo-sea-levelin arctic areas (Blake 1975; Dyke (Fig. 5). These bones cannot have been sie- et al. 1991) because it floats ashore and becomes nificantly reworked, which implies that the whole stranded at the high tide level. Subsequently, carcasswas deposited close to the driftwood limit. storm-waves may throw the wood further up and Sea-level curves from the Arctic are based either bury it in the beach ridge or leave it on the mainly on age determinations on both whalebone surface on or behind the ridge (Fig. 2). This (Forman 1990; Dyke et al. 1991) and driftwood level is the so-called driftwood limit where recent (Salvigsen 1978, 1981). It has been assumedthat driftwood appears as a marked line in the land- whalebone curves and driftwood curves are scape(Fig. 3). The local altitude variation offresh directly comparable because ages from both type driftwood on the present day -r-0.5 shore is within of material plots on a smooth sea-level curve metre at the three investigated locations. Due to (Salvigsen 1978; Forman et al. 1987). However the low gradient from the marine limit to the this has never been rigorously tested. present shore, wave energy reaching the shore At five locations we collected whalebones and has not changed much because of emergence. driftwood from the same shoreline. In addition, Thus, the driftwood limit is believed to be con- Knape (1971) reported three pairs ofsuch samples stant throughout postglacial time. from southern Edgeoya. Fig. 6 shows that the
Fig. 4. Recent driftwood appears as a marked line, called the driftwood limit, on the present beach ridge in Humla (Fig. 1). Photograph towards northeast. Barentsoya seen in the background. 158 S. Bondeuik et al.
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(.) r.aa-cn € 3 € g nQ o r, v) A:A>< p r! ** s s p a HF 5 E n 3 $ o \o6K::=n9 bor) OOO F i* $ $ s F dv € F== 5 = r U eqNP€Rgv^)g E gH s 6h () i 33K3 A 3 = ? nn = :r e O 8K33 g O< Fi* E r € n$ $ = r = E s ; Or)O r- (.) r)6li iO\i* ======+r +t = = = = = E +t +l +r +t +t +t +t +t +t +t +l +t +t +l 60 38R3 I r)NnN g al o\(Do\o\ F R ; $5 il = x = E I tr!cr A:F ,H.-6 6:: AFeeR !9(.) X*Xri E A * 3 4N ^ n ? r 3 R -.:; (J ,'-6i5iql + { { g sK R K F S K K f-FF(t 6 6 a 6 66 6 d i i i i U b:g: \r ! E!i a.) \J 88s: F s s s FN $ ? ! ! I ! TTYd ::r oi E E E E s= E E E E E 3!?r F{ E s8S2 z I 2 2 ZZ z 2 ; ; ; ; '\ o.Y 164 S. Bondeuik et al. above, the ages were not corrected for isotopic fractionation and thus were reported 140 years too young. In arctic areas where the shore is covered with sea ice most of the year, all molluscs live below the low-tide level (Fig. 2) (Aarefjord 1969; Blake 1975). Even the bivalve Mytilw edulis, which is known to inhabit intertidal waters, lived 1G-20 m below the contemporaneous sealevel on Edgelya during the Holocene climatic optium (Hjort & Mangerud 1995). During emergence, shells from older sediments are commonly reworked by waves and redeposited together with younger beach sediments. Therefore, shells provide a Flg. 5. In situ dorsal vertebra of a whale embedded in beacb minimum altitude of the sea level at the obtained gravel in Smelledalen (Fig. 1). The trowel is ca 25 cm long. laC age, but frequently the sea level was con- siderably higher. Evidently, shells are normally calibrated agesplot on a straight 45. line, demon- not suitable as sea-level indicators in these strating that driftwood and whalebones found on regions. Exceptions are shells found close to the the same shoreline yielded similar ages. Knape marine limit where they cannot have been rede- (1971) concluded that the whalebones yielded 125 posited from much older sediments, simply to 420-year younger results than driftwood after becausethe area was covered by glaciersimmedi- substracting a reservoir correction of 400 years ately before the marine limit shore line was for the whalebones. However, as mentioned formed. Whale bone dates(cal yrs Bp) 12000 10000 (86-507,86-508) (87-659B,87-661 ) (st 2485,St 2590) 8000 (86-581,86-580) 6000 4000 2000 (st2660, st 2698) F,g. 6. Dates (88-546, of whale 88-544)& (St2S19, St 2873) bone 0 and driftwood collected on the same shoreline. The 2000 4000 6000 8000 error boxes 10000 12000 show the maximum and the Driftwood (cal minimum calibrated dates yrs BP) age range (one sigma). Postglacialsea-leuel history of EdgeLyaand Barentspya,eastern sualbard 165 Results from the glacier Augnebreen. In the northern part, Augnebreen overrode the Holocene shore- Kapp Ziehen lines during the Little Ice Age (probably during The Kapp Ziehen area (Fig. 1.)is characterisedby the 19th century) (Lefauconnier & Hagen 1991). morphologically well-developed strandlines (Fig. The averagethickness of the littoral sedimentsin 7). The strandlines are cut by rivers originating the shorelines is estimated from rivercuts and Fig. 7. Yertical aeial photograph of Kapp c Ziehen (Fig. 1). Location of radiocarbon dated samples are marked, using the three last digits in the sample (field) number (Table 1). Photograph: ffi Norsk Polarinstitutt S 90- 6602. 166 S. Bondeuik et al. of underlying bedrock to be less rhan in the terraceslope. In ;il:-Or both sections.mainlv well_ rounded. weakly srratifiedgravel The marine with frequent limit is marked by a large terrace shell fragments are present. The gravel is ioose 88.5 m a.s.l. (Fig. 7, sample gl2). Th-ere is an and many rounded cobblesand pebLles lncreasein the havebeerr surfaceslope from 7gm a.s.l. up split by frost action. In one of the sectionsthe to the nearly horizontalmarine limit terrace. Sedi_ gravel grades upwards into a silty ment in the terrace cliamicton on consistsof well_roundedand top of the section. A shell_fragment from the sorted gravel with foresets dipping up to 10. terrace was radiocarbondated to >54.g00 towards the sea. yrs te (Table 2). Amino acids -.o.u."rn"nt's Above the terrace, on . to the south, the rivershave 6 shell fragments, locally including the one that was eroded into (weathered) bedro.t. it. dated. yielded high D7L ratios sediment on top of the bedrock 11oi1carlon is a diamicton (_raDte)). supporting the with frequent, infinite radiocarbon large dolerite boulders that are date. Compared to the D/L ratios trom tne faff both bullet-shapedand striated.We interpret the Ekholm secrion ar Spitsbergen(Mangerud as a glacigenic d lj.aalton. sediment, protably a S-vendsen1992) and till. the sections on Konssova The distinct morphological and sedimentol_ (lngolfsson er al. 1995). the D/L ratios ogical boundary between sulggesi the terrace and the drs_ an E,arlyWeichselian, sected or older age, for tnel"nett diamicton marks the position of the marine fragments. limit. In the field we interpreted the diamicton Dated samples with to be _ description are listed rn of the same origin Table as the silt_rich surface soil 1. A search for pumice on the raised mentioned above, which coversmost of the Hol_ beaches yielded only rwo pteces, at 34.3 and ocene terraces. However. if 42.2ma.s.l. the diamicton is a till, the terrace may be compared with the g7 m terrace in Linnddalen on the western coast of Spitsbergen Humla (Mangerud et al. 1992a).Inthat case the terrace is not related to the post_glacialsea The small bay Humla (Humla is formallv the level (marine limit). If we had name of ino*i that the the river entering the bay). is locatedon shell .,old,', fragmentswere we would have inves_ the northeast corner of EdgeOya and faces the tigaled the diamicton more carefullv. open Barents Sea (Fig. 1). Most of the surface Along the mountainsidewest below the of Humla, there marine limit consistsof sandund g.ouel, is a small abrasion cliff in bedrock with its foot although it is generallycovered by a thin liyer of at approximately the same peat or altitude as the a silt-rich surfacesoil formed bv crr_ 86.8m a.s.l. terrace (arrow in Fig. g). Above this oturbation, solifluction,and accumulation oiwind smallcliff, glaciallystriated and polished blown silt (Fig. a). boulders are common in stream Raised bottoms, indicating a till beachesare distinct from the present at the surface,which was not found in the upper un to approximately 35 m a.s.l. (samples 1!1re 2 m of sediments below the cliff 508 and 676,Fig. g). . This supporti ihe Ar this levelthere is a b to interpretation g6.g that the m terrace i, ,"tut".t to 10 m high step or cliff in bedrock. Above the cliff the post glacial sea-level. Whether the terrain rises the terrace gently, and only subdued beach was formed by erosion in old sediments at the torms can be identified.A series of distinctshore_ postglacial marine limit lines appear or the shell fragments again from about 70 to 7g.gm a.s.l. were redepositedfrom higher elevationsiannor (between sample 533 and 525, Fig. S;. nuritrer be determined. In up-valley any case,we considerthe ter_ on the east side of the river Humla. race to representthe postglacialmarine a small terrace with shell limit. fragments occurs at Also the altitudecorrelales 86.8ma.s.1. well with otherobser_ (sample 516, Fig. 8). Age Oeter_ vations "are of the postglacial marine limit on Bar_ minations with description of samples listed entsoya and Edgeoya (see below). in Table 2. No marine sediments were found above the terrace Diskobukta at 86.8 m a.s.l. (Fig. g), ana aurine fieil work we assumed that it representedthe'post- Diskobukta, situatedon the westernside of Edg- glacial marine limit. we made two small exca- eoya, faces towards storfjorden vatlons (0'9 (Fig. 1). ;hg; and 1'4 m deep) down to permafrost two valleys Raddedalen and Smelledalenenrer Postglacial sea-Ieuel history of Edgeqya and Barents@ya,eastern Sualbard 167 Fig. 8. Vertical aerial photograph of Humla (Fig. 1). Location of radiocarbon dated samples are marked, using the three last digits in the sample (field) number (Table 2). Arrow (lower left side) points to the ablation cliff with the same altitude as the marine limit terrace. Photograph: Norsk Polarinstitutt S 90-2404. Table 5. Amino acidDlL ratios from the 86.8m a.s l. terrace at Humla DIL Field no. Lab. no. Species Total Free 88-516,4 BAL2709 Mya truncata 0.071t 0.003 0.395t 0.005 + 88-5168 BALNl.O Hiatella arctica? 0.059: 0.005 0.357 0.049 88-516C BAL271L Hiatella arctica 0.077a 0.006 0.329t 0.006 88-517A BALNlz Mya truncata 0.075 0.348 + 88-5178 BAL2713 Hiatella arctica? 0.087 0.003 0.496t 0.006 88-517C BALNM Mya truncata 0.120r 0.002 0.373t 0.046 Amino acid D/L (D-alloisoleucine/L-isoleucine) ratios in shell fragments found in the 86.8 m a.s l' terrace at Humla. Samples 88- 5L6A-C are fragments picked directly from the section, and 88-517A-C are fragments found on the surface of the terrace slope. 168 S. Bondeoik et al. {Wi.7.:: S:lre ;:l! .G 6:: :'66 :! :,; Fig' 9' Yertical aerial photograph of Diskobukta, Raddedalen and smelledalen (Fig. 1). Locatron of radiocarbon dated samples are marked, using the three last digits in the sample (field) number (Table phoiograph: 3). Norsk polarinstitutt S 90-2649, 2650 & S 90-6613. S 90- Postglucial sea-leuelhistorv of Etlge6,vaand Barents|va, eosternSualbartl 169 Raddesletta (slettu in Norwegian means plainl prior to 7000 years Bp for southern Edgeoya about 5 km from the presentshore (Fig. 1). Rad- However, these data are plotted together with desletta is a coastal plain with a well-developed Knape's data from Negerdalen,and the courseof braided river system(Fig. 9). A continuousseries sea level is indicated by a stippled line (Fig. 14). of raised shorelinesappears on Raddeslettafrom the shoreto about 17m a.s.l.(Fig. 9, sample582). The marine limit on Edgeqya Terraceswhich consistof marine sedimentsoccur and BarentsOvu on both sidesof Raddedalenfrom 23 m (Fig. 9. As a result of weathering and solifluction pro- sample 566) to the marine limit (Fig. 9. sample cessesin the soft and schistoserocks. the marine 572). except for the interval between 45 to 60 m limit is not morphologically well marked. Our (Fig. 9. between samples 325 and 573), where best measurementsof the marine limit are from sedimentshave been removed bv slopeprocesses Kapp Ziehen. Humla and Diskobukta and are Dated samples with descriptions are listed in between 85 and 89 m a.s.l. (describedabovel for Table 3. other observationsof marine limits on Edgeoya On the easternside of the river in Raddedalen. and Barentsoya,see Mangerud et al. 1992b). approximately9 km from the presentshore, there Knape (1971) concluded that the marine limit is a larqe terrace (Fig. 9. samples5tt5 and 572). on the western coast of EdgeOya was about Sectionsin the terraceshow sandand gravel beds 90m a.s.l.and on the eastcoast 95 m a.s.l.This clippingboth clown and up valley. The deposit is assumptionwas based on altimeter reaclingsbv inferred to be a large spit formed by longitudinai himselfand by Glaser ( 1968)on the westerncoast drift from the south. Shell fragmentswere found of Edgeoya. and by Bndel ( 1962. 1968)on the rn gravel bedsnear the terracesurface. Two fiag- eastern and northern coasts of Edeeova. ments were dated to i1.685-11.290cal vrs sp However. our data do not show anv ,ignificirnt (TUa-.1.11{) ilnd l{t.9J{rlil.olU cirl urr ur lTUo- differencein altitude of the marine limit between 627). rcspectivelv. The highest point on the the western and easterncoasts of Edgeoya. Our depositis found ncar the vallev slope, 85.1 m a.s.l. observationsalso implv that Knape'saltitudes are I{ere rounded pebbles occur frequently on the slightly overestimated.We are not conlldent that surface.ancl outcrops show sand and gravel beds the measured differencesobtained by us reflect dipping towards the valley side. From this we real differencesin elevation of the marine limit. concludethat 135.1m a.s.l.is a minirnumvalue for and we therefbreconservatively conclude that the the marine lirnit in Radcleclalen.Marine sedi- marine limit is 8-5to 90 m above sea level on ments were not found at higher elevationsin this Barentsoyaand northern EdgeOya. vallev. In southern EdgeOya the data :rre scarcer. Knape ( 1971)reported a beachridge at 72 m a.s.l. overlain by an Southern Fltlge4,vu end moraine in front of llart- mannbreenjust east of BjOrnbukta(Fig. i). In The sea-levelcurvc constructedby Knape ( 1971) Negerdalen the highest terrace is 75 m a.s.l. tor southern Eclgeoya lacked ages above (Knape 1971).Both these elevationsare mini- 53 m a.s.l. Knape collected the samples in mum values and are based on barometric 'fhe Bjornbukta and Neperdalen(Fie. l) and leveileci readings. altitudes on the terrace in Dian- all altitudesexcept the uppermostsample of drift- adalen are even more uncertain becausethey wood (-53rn a.s.l.).which was measuredwith an were measuredonly once. In spite of the scarce altimeter. data. it seemslikely that the marine limit on In Dianadalen(Fig. l) situatedl-5 km north of the southern part of E,dgeOyais berween 75 ancl Negerdalen. we collected three samplesclose to 80 m a.s.l., and is thus just a lew metres lower themarine limit (Fig. 10:Table 4). Unfortunatelv. than on the nurthern part of the island. due to harsh weather conditions. these terraces and sampleswere not levelled,and the barometric (:onstruction readings were not rechecked. Because of the ol sea-IeLteIcurLte.s uncertainties in altitudes for the Dianadalen Measurement errors on the samples are small samplesand a possibledifference in emergence both concerning altitude iind age. and errors between Dianadalen and Negerdalen. we have should be random on each sicleof the real value. not constructecia sea-levelcurve for the oeriod Evidently, most samplesshould plot on or close t70 S. Bondeuiket al. L---:-J-.: -afs#:- Fig. 10. Vertical aerial photograph of Dianadalen (Fig. 1). Location of radiocarbon dated sanples are marked, using the three last digits in the sample (field) number (Table 4). Photograph: Norsk Polarinstitutt S 90- 6634. to the true sea-level curve. Therefore, we have short-lived variations in the rate of eustatic sea- defined the sealevel curves by fitting the drift- level rise must have occurred. However, these wood and whale bone dates with a least square variations could hardly have been detected with regression curve. The advantage of this approach the available dating accuracy. is first of all that the curve represents an objective We have tested different functions (second- mean of the individual data points. Secondly, the order function, exponential function, etc.) on the sea-level curve is expressed by a mathematical datasets. To obtain the best fit, the dataset from equation that may be used to calculate the rate each locality had to be split into two groups: dates of change and quantify the differences in sea-level older and dates younger than 7000 years Bp. We change between different areas. The weakness of obtained a third-order function for the dates older this method is that the constructed sea-level curve than 7000 years Bp and a second order function is probably smoother than the real curve because for the dates younger than 7000 years Bp. The Postglacial sea-lenelhistory of EdgeOyaantl Barents,vo, (.asternSualbartl 171 goodnessof fit is between0.97-0.99 for all curves. the west acrossthe peninsula.It is thereforelikely Sea-levelcurves for the four localitiesare shown that Kapp Ziehen was deglaciatedearlier than in Figs. 11-14. Frankenhalvoya(Landvik et al. 1992).However As pointed out by Andrews ( 1986)and Pirazzoli at Kapp Ziehen the large whale bone found in (1991), it is important not only to plot the sea- the marine limit terrace was dated to 10.930- level index point but also to include the uncer- 10,71J5cal yrs ae (Table 1, T-9913).Because of the tainty associatedwith each point on the sea-level old date from Frankenhalvoya, the Kapp Ziehen graph. On the sea-levelcurves (Figs. 11-14) the sample was redated, but with a similar result age range of one standard deviation of the cali- (10.835-10,475cai yrs ae, T-9913I). Two ageson brated radiocarbonages is drawn. This calibrated shell fragments from Blifjorddalen and Dian- age range varies from 100 to ,500years (Tables I adalen (Fig. 1) also tend to push the date of to 4, columns A and D). At about 10,000cal vrs deglaciation1000 cal yearsback in time (Landvik BP.the emergencewas abour 2Ummlyear (Fig. et al. 1992)compared to the sea-levelcurves. 15), and an age range of 300 years corresponds On the western coast of Spitsbergen(Fig. 1) to an altitudinal range of +6.0m. In the lower there are arguments for a nearly stable relative part of the curve, at about 4000 cal yrs Bp, the sea level between about 12.500to 11.000cal vrs r'C sameage range would correspondto an altitudinal Bp ( 10.700and 9700 yrs ee) (Landvik et al. +1.-5 rangeof m. 1987; Lehman & Forman 1992). The reason is The altitudinal uncertaintyconsists of errors in postulatedto be an ice growth during the Younger determining the driftwood limit, variation in the Dryas in eastern Svalbard, such that the rate of driftwood limit and errors in levelline of the glacio-isostaticrebound was reducedor reversed. samples.These errors sum up to about a I rn. A. This implies a stillstandor reduced rate of uplift illustrated, the main uncertaintyprior to ca 5000 alsoheneath the ice sheetcovering Edgeoya and cal yrs Bp is a result of the imprecision of the Barentsoya. The subsequent deglaciation was calibrated radiocarbon ages, whereas the alti- rapid becauseof calving. It is therefore possible tudinal measurementerrors, which are not more that the inceptionof rapid uplift was delayeduntil +1m, than become more important after 5000 E,dgeoyaand Barentsoya were ice-free. and that cal yrs ne, due to lower emergencerates. the last phase of the abovementionedstillstand causeda stable sea level during the first period after the deglaciation. There are severalarguments against this inter- Relative sea-levelhistory pretatlon: (1) The timing is problematic. If the stillstand The initial phase: stable or rapidly falting sea- leuel? on the western coastwas due to ice growth in the east, then Barentsoya and Edgeoya must have As constructed, the sea-levelcurves indicate a been ice-coveredduring most of the stillstand. rapid fall from the marine limit immediatelv However, the shell dates from Barentsoya and after deglaciarion(Figs. ll-14). The sea-level Edgeoya cover most of the stillstand period in curvesalso suggestthat the marine limit on both western Spitsbergen. Edgeoya and Barentsoya was formed almost (2) The shorelinesformed during this period on simultaneouslyabout 11,000cal yrs ae (Figs. 11_ the western coastof Spitsbergenare very distinct l4). However, someages on shellsin glaciomarine (large beach ridges and terraces) compared to sediments indicate that the deglaciation occurred younger shorelines. This morphological differ- approximately 1000cal yearsearlier (seebelow). ence in shorelineshas been used as an argument If these results are correct, then sea level for a stableor transgressivesea level (Landvik et remained stable during this early phase. al. 1987; Forman et al. 1987). The shorelines On Frankenhalvoya (Fig. 1), 15km west of from this period on E,dgeoyaand Barents6ya are Kapp Ziehen, Landvik et al. (1992) found the similar to younger shorelines formed during rapid bivalve Nuculana pernula in glacio-marine sedi- emergence. ments located about 3 m above the base of the (3) Also. if this interpretationis correcr.we l4C sequence. A sample was dated to 10,265+ 95 would expect a gradual increase in emergence yrs ne (Ua-2536) (12,235-11.750cal yrs ee). The rate after the stillstand. whereas the curves are last ice movement on Frankenhalvoya was from steep from the outset (Figs. 11-14). 172 S. Bondeuik et al. 90 80 7i - q60 (I' o Driftwood -3U + Whale bone .F540 o Fig. 11. Relative sea-level (l) tr curve for Kapp Ziehen. The ZU calculated regression equation prior to 7000 cal 10 yrs BPis: y (m a.s.l.): Presentdriltwood limit 1.80311.10'!xr 4.40261. 10 sxr+ 0.363333x 975.5 After 7000 cal yrs ne: y : 'xr Cal yr BP 10000 8000 4000 2000 4.13627 . 10 + 5.25669. ax Gl4yrBP l0 + 3.6t1727(x : cal yrs rdm BM ffi 4m 2m BP). 90 Marinelimit 80 70 l a. 60 (0 Driftwood -uJ Whalebone 540 Shellfragm. (I' fig. 12.Relative sca,levcl (D curvcfor Humla. Thc rii calculatedrcgression 2U equationprior to 7000cal yrsrr is:t (ma.s.l.) - 10 1.2693-5.10exr- 3.111,11. _ __l!9?91!{'rlly_qgol,li!_ l_=- 10 5xr+ 0.261035x 708.lu7. Aftcr 7000cal yrs Cal yr BP 10000 8000 6000 4000 2000 0 up:v:3.68251. l0 rxr+ I.27263. rx G14yr BP 1m 8m ffi 4m 2m 0 10 + 2.7336-5. We have no ready explanation to this dis- occurred within the first 2000 years after the deg- crepancy between the ages on the three abov- laciation. A half-responsetime of 2000 years is ementioned shells and the sea-level curves. common tbr emergencecurves from deglaciated According to the sea-level data it seems most areas(Dyke et al. l99l). reasonablethat the sea-levelcurves fell rapidlv from the marine limit following deglaciationat Transgression between 9000-7000 cal yrs ar? about 11,000cal yrs Bp. At about 9000cal yrs Bp. the relative sea level A transgressionin I{olocenetime is reportedfrom was as tow as 40--4-5m a.s.l. (Figs. 11-l'1). This severalsites in western Spitsbergen(Landvik et meansthat half of the total postgiacialemergence al. 19t37;Forman et al. 1987;Salvigsen et al. 1990) Postglacial sea-leuelhistory of Edge/ya and Barentsqya, easternSualbard 1173 on Marinelimit 80 70 ..--: a. 60 o Driftwood ECU r Whalebone 'j=d40 (U Shellfragm. fig. ,/.i. Relative sea-level curve for Diskobukta. Thc o calculated regression tr ZU equation prior to 7000 cal yrs tsPis: y (m a.s.l.) : 10 1.48743.10 exr 3.(fi4'14. \0 5x2+ (J.296124x - Presenl 792.632. After 7000 cal yrs 0 BPi y - 2.91197. Cal yr BP 10000 8000 4000 2000 l0'1x2 + L62237. 10-jx + 1.23663. ClayrBP,fu w ffi 4m 20@ an 80 70 ---i ur. 60 (I' E50 (- 640 fig. 14. Relative sealevel Fo ^ Shellfragm. curve for Southern d30 EdgeOya. Due to tri uncertainties with the data zv prior to TU)Ocal yrs B.P. no sea level equation is 10 calculated for this period. After 7000 cal yrs nr the Presentdriftwood limit calculatcd regression 0 equation is: y (m a.s.l.) = Cal yr BP 10000 8000 4000 2W 3.94446.101x2 + 1.47141. rx 10 + 1.21t223. C14yr BP 1W 8m ffi 4m 2W and from Nordaustlandet (Hyvdrinen 1969). On the Holocene transgressionon Svalbard (Landvik Talaveraflya, southwestern Barentsoya (Fig. 1), et al. 1987; Forman 1990). According to the Feyling-Hanssen(1965) described a 2 to 4cm curves (Figs. 11-14), sea level cannot possibly thick layer with terrestrial plant remains covered have been aslow as 12.6m a.s.l.. 7000to 6000cal by marine sediments at 12.6ma.s.l. The layer, years ago. The terrestrial plant remains must have interpreted by him to be a terrestrial peat, was been redepositedin shallow seawater. The name raC dated at 7270-6360 cal yrs ne (6OOO* 400 yrs Talavera Transgression should thus be aban- nr), and the overlying marine sediments were doned. consequently interpreted as indicating a trans- Between 8500 and 8000 cal yrs Bp the rate of gression.Talavera is later used as the name for emergencewas less than l0 mm/year for all three 174 S. Bondeuik et al. RATEOF CHANGE m a.s.t. mm/year 50 140 rsostasy 45 120 (Kapp Ziehen+ Barbados) 40 35 KappZiehen Humla 30 KappZiehen Diskobukta (rel.sea-level) 25 SouthernEdgegya 20 15 10 5 0 f. Barbados '\\ (eustatic) 10000 8000 60@ : Cal yrs BP I flg. 1.5. Ratc of changc firr the four krcalitics obtaincd bv dill(rcnli.rtinplh\. rcl.rtr\c \cir-l\.\cl cqurlion\ rl-rgs 11. 1.. 1r -\:_ and 1,1).For thc last 7(l(X)cal vcars. thc ratcs for llurnla and Disk()buktalie bctu,centhc curvcs shou'nlor SouthcrnEdgcova 0 4000 Bo00 12000 16000 2oooo and Kapp Zichen. Calyrs Bp Frg. /6. Calibrated coral datcs (=calcndar vears) from thc curves(Fig. l-5). considerabll,lower than during Barbados sea-lcvelcurvc ( Fairbanks I 9tl9) plottcd togcthcr u,itlr preceding and subsequent periods. A rcduceci thc scalcvclcurve frorn Kapp Ziehcn. Ihc isostasvcurvc drarvn ratc of emergence is also shown by Landvik e1 herci\ \rmnl\ the K;rppZicherr currc rrndth. cu.t:rti.\cir-lL,\cl curve addcd togcthcr. Thc reduccd ratc ol al. (1987) for severalcurves on Svalbard.Thc cntcrgcncc obscrt ed bctwecn 9(X)0 and 7000 cal lrs Llp is causcd b\ a sustaincd cmergencecurve from (Salvigsen Svartknausflya eustaticsca lcvcl rise parallelwith a dccrcascdratc of isostatic l97tl). on the southern part of Nordaustlandet uplift. (Fig. 1). showsthe samepattern with a recluced riite ot emergencein this period. C)nthe northern part of Nordaustlandet.Blakc ( 1961) describeda rncreasedemergence rates after 8000 cal yrs ep well-dcveloped beach. about 73(X)cal years old. are causedby the levellingout of the eustaticsea- that is cut into bedrockin manv places.This, he level rise. argued.indicates a balanccbetwcen the isostatic uplift of the land and the custaticrise of the sea. This cannot be seenon Barentsoyaand Edgeoya. In order to explain this reduced rate in emerg- ence. we have compared the eustatic sea-level Regional implications curve from Barbados(Fairbanks 1989) (calibrated Isobasemup 10,0001aC er: to calendar Vears)with the sea-levelcurves from vears I 1,000cal v-rs BP E,dgeOyaand BarentsOya.Sea-level changes are not globally uniform becauseof changesin the Deglaciation ages suggest an almost instan- geoid(Fjeldskaar 1989). However. as the change taneousand final withdrawal of the last ice_sheet rn gravity 'oC between Barbados and Svalbard has on Svalbard at 10,000 v.s Bp (Mangerud et probablv been insignificantduring the last 900() al. 1992a).Subsequently the entire archipelago vears, the Barbados curve gives a good approxi- emerged extremely rapiclly (Forman 1990). An mation for the eustaticsea-level changes on Sval- isobase map showing the elevation of raised (Fjelclskrur hard pers. comm. 1995).It is clear beachesjust before this rapid uplift startedwould from Fig. l6 that the reasonfor the sloweremerg- depict the load of the melted ice massesbetter ence is the result of a sustained eustatic rise than isobasemaps for younger periods. Isobase together with a decreasedisostatic uplift. The maps for other periods have been presented Postglacial sea-leuelhistory oJ Edgerpyaand Barentslya, easternSualbard I'75 Iable (t. Sctrlcvcl clatalor thc 10.0(X)r'C rrs Bp isobascmap. I.ocalitr ILcferencc Se.r le're I ('onnre lls I ) Nlilrrhalrrla Firnran i990 15 llroad terrrcc irl l: n a.:.1.dated to ll).-1j0:! -l-10\rs Bp 2) Bro{gerhrrlvina lirrnan ct al. l9E7 -]l) Largc raiscd barricr bcach prcscnt rt lt) nr a.s.l. Whrlc ritr at -10m a.:.1.datcd to t)7-15:t l-15\r\ BI, 3) I). Karls lirrlancl Fornrrn 1990 .10 ('trnstructionirlbcach ridcc iil J{}rl r.s.l. Whrlcboncs at -]l m daled to 10.610:r l6(l rrs Bp rnLi lS n diilcd t() 97()():! 130 YTS BP -1)l)auilnannsrnra Forman 1990 -1] Whalcbonc at Jl m ir.s.l.dalcd to l0.0li0 t -ll{) \r\ IJp 5) L3ohenranflva Srrlvigscnct rl. l9(.)0 55 57 \\'ashinglinit rt 60ma.\.1. Sc-r-lcrclintcrpreteci to be \onc\\hat morc thrn 55 n a.s.l. (r) Kapp Fkholrtt Sirlvi{scnl9il-1 65 it'l I'icce of uootl at 6-:m a.s.l. datcd to i0.0.i0 :t l-10\'rs BP \'larketl terrace at li-lnr a.s.l..possiblr mirrinc limit. but shcll fflsment vicldecjinlinitc rrgcs(\lrrntcrutl & Srlrigscn unpu0l.,. 7) I.inncltlalen Sandahl 191t6 .lE \\'ood fronr trrrrcc 3j nt ii.\.I. drlcd to 9(.)ll0:! 70 \'r\ tjp \\'halcborc .19.5nr r.:.1. rlrrtctlto l0-{)10t l-10\r\ t}p li) \'llerclrrlcn Landvik et al. l9iJ7 50 l]cach lcrcl L] parallcl uitlr \-ordcnskiirlilkrstcnilated to lll.60(li lll) \r\ Bl' 9)NW\\'..l.hcrglantl Srlrigscnclirl.l99l -17'-+0 BcrrchlcrciB.l-hisbcachriscssli{htlvfr()rr\\e\1louiir(l\ clsL l0) N\\'Sorkappland Sahigscn ct El{crsnra 199.1 .1(l Bcrch lscl B. I l) L3jrlrnorr Salriuscn& Slcltcmirrk 1995 ':0 \o e'lcrate'clshorcljnes. ll) Asrrrtlhbuktrr Salrigsenct N4angcrud1991 5l ()0 Tcrrxcc at -:lna.s.l. dalcd 1o 9ii70 t l-l(l vrs lll'P(xsiblv lhe marinc linrit. Altitucic rc checkctlbr Srlrigsertdi l\1an{crucl1991. Not :-61)mr.\.1. l-cctonic subsidcncc.) l.j) Diskoirukta 1'hispape r s5 l-1)S. I:clse!)ra This papcr ii(l )5; Ilopcn Zale & Bntlstcn ltl9-l 6(l Driitrvrrrdrl 5Enrr.s.l datcdto 9tl)(11 ll0 \rs Ill'( ur\c cxtrrp()lrlcdback to ll).0(){)\rs tll'lron llri\ drtc. 'l'his 16) I lurrlrr papeI ll7 17) Kapp Z-ichcn This papcr 39 lll) Wilhclns(jva Knrpe l97i 15 Cur\c c\trapolitted back to 10.0(10\r\ IIP fr()nr$hrlci)()ne rt 57 nr r.\.1. tlatcclto 9-1-.15r 155 r'rs t'tt 19)Svrrrtknausllrl Sal\igsen197fi 75 Whrleboncdatctlto9(rl()l ll0\r\ul'rtf() nrr.s.l. lhe l{).000\eir lcrcl is probablr a littlc highcr. l0) Konusllta Salrigscnlglll l()() Srnrpl!'\11l0(lnra.s.l.datc(ito9S5()iflO\rstll'l-herlarinc linrit crcectl lhc 100n) lcrel slightlr'. ll) Stor{tlr Jonssonl9E3 66 l:xtrapolation()l cur\e to iltarinclinit ((]f)nli.s.l.) suggests dcghciation rt 10.{)00\ rs BP 3l) P. Oscrrrsl-irncl Osterholnt l9()0 Dcqlaciationbct\\'ccr 11.{100ancl 10.0{)(}rrs ttl' Krircmcrhrrklir 57 N{arinelinrit. 7-orgdrirgcrfjorden -l-l Nlarinc liruit. 23) Nlurchisontjorclcn Blake 1961 55 ('ur\e e\trapoliited to l0.l)(X)\rs IIPfr()nr shell da(cd t() 96.10]! ll0 \rs rlp at -1-lm r.s.l. 2.1)Sjuorane Salvigsenunpubl. l(l \larinc lirrrit.arca dcglrciate'drrrourd l0.ll01)r'rs ttt' 35; Mossclbukta Sirlvigsen c! Oslcrholnr l9fil -10 Are a dcqlaciatctlapproxinale lr ll.()l)0 \'r\ tll' Llcvati()n rcad off frorn curvc. 26) Grahukcn Srlr,igscn.t Ostcrholnr l9lll 17 Arca dcglircirteclapproxirratclr I 1.()()(lrrs BI' [rlcvrtion rcad ofi lronr curvc- l7) W of Rcinsdvrllta Lchnran & Forrran 1987 0 0-isobascmrrks thc bounclart for clc\irtc(l shorclincs. !C'datcs Thc altitudc,la{ei\ supportcd bv a sca lercl cur\e hascdon sevcLlrl c\ccpt ll) 13jttnorltltnd 16) W of I{einsdvlllva.'\ll datcs in r'(l vcars ItP. before (Schvttet al. 1968:Boulton et al. l9ll2: 10.(100rrC vrs Bp isobasemap. ln westernSpits- Forman 1990 and Forman et al. 1995).Table 6 bergen the emergencewas slow at that time. and shows thc sca-lcvcl data used to construct thc thus an crror in dating would not result in a large 176 S. Bondeuik et al ao3 ?t [- I \ \ -*__\\_ 15 \_ ____60 \\\\\ -\\\\\ -\ ______ g---_T___iok' Flg l T Isobase map for IlC Svalbard showing the present elcvation of shorelinesformed approximatelv 10.000 yrs Bp. The altitude (first number) and locality (raised number. see table 6) are siven for each site. I'ostglacial sea-leuelhistory oJ EdgeOyaand Barents@va,eastern Sualbard 17':- error in elevation. ln easternSvalbard, however, m a.s.l. emergencewas rapid, and the estimatedsea level 90 at the time of deglaciationmay underestimatethe altitude of the 10,000raC level.. 80 The uplift dome has a circular/elliptic shape 70 and is limited in extension towards the north. 60 southand west.The distance betweenthe isobases 50 lncreasesfrom the edge towards the centre, indi- 40 cating a relatively thin and low gradient ice sheet over eastern Svalbard and adjacent parts of the 30 Barents Sea, as previously shown by the model- 20 ling of glacial rebound in the Svalbard-Barents 10 Sea area (Lambeck 1995; Elverhoi 1993). The 0 observationsfrom E,dgeOyaand Barentsoyacon- 12000 10000 8000 6000 40oo 2ooo o firm this general picture of emergence on Cal yrs BP Svalbard. The almost identical curves together with similar marine limit observationssuggest that raC lig. 1E. Calibrated dates of driftwood samples(mean value) the area between Diskobukta-Humla-Kapp for Stor6ya (Jonsson 1983) and Itopen (Hoppe et al. 1969:Zale Ziehen has emerged without any noticeable & Brydsten 1993). The cunes through rhc datapoints are drawn tilting. Thus the localitiesshould be found on the as originally published. Thc datings bctween 1l,tD0 and 900() cal vrs Bp coincide for both localities. same isobasesthroughout the Holocene. Most but aftcr 7000 cal yrs er the two datasets clearly diverge with the data from Storoya data fit well with the isobasemap (Fig. 17), but being 5-6m below the data from Hopen. one evidentexception is Agardhbukta. According to the constructedmap, the sea level 10,000raC yrs ne should be close to 80ma.s.l. (Fig. 17). whereas the observationssuggest a marine limit between52 and 60 m a.s.l. (Table 6). The reason The observed differences in emergencerates for this is unknown. but one alternative is that between southern F.dgeayaand Kapp Ziehen and this discrepancywas caused by largescale faulting between Storoya and Hopen could be caused (in Storfjorden?). l:y an isostatic memory of a larger and earlier downwarping in the southern Barents Sea.From Indications of an earlier and larger uplilt-centre 11,000 to 9000 cal yrs Bp the emergence at in the southern Barents Sea? all discussedsites was dominated by the rapid iso- The emergence rate on southern Edge6ya was static uplift due to the final rapid glacial unloading greater than at Kapp Ziehen through the last 7000 of Svalbardand the northern Barents Sea,as also cal years(Fig. 15), eventhough the marine limit is is shown on the western coast of Spitsbergen lower on southern Edgeoya. Stor0yaand Hopen, (Landvik et al. 1987; Forman 1990; Mangerud situated northeast and southeastof Barents6ya- et al. 1992a). When the uplift from rhat centre Edgeoya, respectively (Fig. 1), show the same decreased (after 7000 cal yrs Bp), the remnant pattern. The marine limit on Stor0yais 66 m a.s.l. rsostaticrebound from the loading of the southern and was formed approximately 11,000cal years Barents Sea became visible as faster uolift in the ago (Jonsson 1983). On Hopen the postglacial southernarea than further north. marine limit is more than 60m a.s.l. (Hoppe et Fjeldskaar (pers. comm. 1994) and Breuer & al. 1969;Zale & Brydsten 1993).By extrapolating Wolf (1995) point out the possibilityof a lateral the curve from Hopen, the sealevel at 11,000cal change in mantle viscosity from east to west to yrs BP is ca 60 m o.h. During the first 2000 years explain the difference in uplift rates between west- after the deglaciation the emergence curves are ern and eastern Svalbard. This could be an parallel (Fig. 18), but at about 7000cal yearsthe alternative explanation to the different emerg- curvesstart to diverge.During the last 3000years ence rate between Stor6ya and Hopen, and the emergenceon Storoya has been only ca 2 m between Kapp Ziehen and southern Edge@ya, whereas at Hopen it has been ca 7 m (numbers with increasing mantle viscosity towards the are corrected for different present-dav driftwood south, away from the plate boundary north of limits). Nordaustlandet. l7u S. Bontlet,ik et ul Sea ice conditions in thc Art'tir' Ocean A Conclusions References Due to frequent and well-preserveddriftwood. Aarefjord. F. I969: Frozcnup I.ittorinasrrxatilis Olivi in thc relative sea-levelchanges in easternSvalbard can iccfoot in Spitsbcrgcn.,"trtnsk Polurint. '1rfutk1967.l10 l-11. be mappcd ir-rgreat detail. The sea-levelcurves Andrcu:. J. L l970: A geotrtorpholttgiculstudt ol post-gluiul uplitt rlith purticulur rrlcr(il(( kt ,.1xtit ( urtudrt.ln\titutc ol from Edgeo,"-a-Barcnts6yaare among the most 13ritishCieographcrs. Spccial Publicrrlior. r"o l. 156pp. accurateand bestdated Holoccne sea-levelcurves Andre*s..1.T. 191i6:Elcvations rnd rge rcllrlionrhips:liisctl fronr the Arctic. marinc clcposilsand lanclforntsin illrciatcclareas. F.rltmplcs Between I l.(XX)and 10.(XX)cal vrs BP.the sea- bascd on Canadian Arctic datx. I)p.67 95 in Orson vtn dc Plasschc(cd): .\tu-laoclrtscurch; u ntunrtul tht tolltctiort lcvel curvesshow a rapid emergence(.1(I-20 mm/ .lor artd crulutttittrtol dttu. lrce t.lnircrsitr. Anrslerdrn. year). Illakc. W.. .lr. 1961:Radiocarbon tlirtin{ ol niiscd bcacltcsin All curves indicate a slower rate of emergence Nr)rdrusllandct.Spitsbcrgen. Pp. l-l-1 l15 in Rirrrsch.(i. O. between9(XX) and 7000cal yrs BPwith a minimum (cd): Cieolo,gr()l lhe Arcli(. Liniversitv of Toronto. T()ronto. at ca 82(X)cal vrs LrP.This is explained by a Blakc.W.. Jr. 197{):Studicsof glacial histon in Arctic('anada. L Purnice. lrdiocarbon datcs. and tlilfcrcntirl postglacial sea-levelrise parallel with a sustained eustatic uplift in thc caslcrr Quccn Elizrbcth lslancls.( rar.-/. /:crl,/i decreasedisostatic uplift. 5tr. Z. 63f661. The terrestrial plant remains on Talaveraflva Blake. W...lr. 1975:Radiocurbon agc dctcrnrinationsand post- (Feyling-I{anssen196-5) that have been used as a glacill cmcrgcnccat ('apc Storm- southcrnEllcsmcrc Island. Arctic C'anada.Oeogr. tltttt. -i7. serics A. I 71. proof of a transgressionin mid Holocene time Bondcvik. S. 199.i:Pov,q1a.siul :trundlltrskvt,ing Itu Spulbunl. must have been redcpositedin shallowsea water. t,'npublishcdthcsis. Llnivcrsitvof flcrccr. 71)+ !i1 pp. 'l The name Taluuera Transgressionshould thus be Boulton.Ci. S.. Baldwin.C. .. Peacock.J. D.. NIcCabc.A. abandoned. M.. Millcr . G. . Jarvis.J.. Horsctield. 13.. Worslcy. P.. El les. The uplift rateson southernEdgeoya are higher N.. Chroston.P. \.. Dav.'I'. L.. Ciibbard.P.. llarc. I'. E. & r'on Brunn. \'. l9El: A glaci{>isostaticfacics nrodcl and Barentsoyaduring than on northern E,dgeoyaand amino acid stratigraphvlirr Lalc Quatcrnarv cvcnts in Spits- the last 7000cal yrs. Through further comparison bcrgen anclthe Arctic. Ntntre 298.:137-111. of the sea-levelcurves from Storoya and Hopen. Brcuer. D. & Wolf. D. 1995: Dcglaciirllrncl enrcrgcnccand we suggestthat a memory of an earlier and larger lateral uppcr mantlc hctcrogcncit! in thc Svalbard Archi- pelago L Firsl results hrr simplc load modcls. Oeopht;. J. glacio-isostaticdownwarping in the southernBar- lnt. l)1.115 18E. ents Sea is detected in the sea-levelcurves from Budcl. J. l96l: I)ic Abtragungs Vorgiingc ruf Spitzbcreenim Hopen and southern Edgeoya. Llmkrcis dcr Barcnts Inscl auf Grund dcr Staufcrlands The sea-levelcurves and marine limit obser- Expcdition 1959i60. Dcutc:her Ongntplrcntug Ktiln 22. 26. vations fmm the northern part of EdgeOya(Dis- Mui l96l. Iugungsbcri Eggcrtsson. O. 1994: Driftwood as an indicatrtr of relative Landvik. J. Y.. Mangerud. J. & Salvigscn.O. l9g7: The late changcs in the influx of Arctic and Atlantic water into thc Weichselian and Holoccnc shorelinc displacement on the coirstal arcas of Svalbard. Polar Res.1-t, 209-21g. west-cenlral coast of Svalbard. polar Res.5. Zg_41. Elvcrhoi, A.. Fjcldskaar. W.. Solheim. A.. Nyland-Berg. M. Landvik. J. Y.. Hansen. A.. Kelly. M.. Salvigscn.O.. Slet_ & Russwurm. L. 1993: Thc Barcnts Sea ice-shect: A model temark. O. & Stupdrup. O. p. 1992: Thc last deglaciation of its growth and dccay during the last ice maximum. eucr. and glacimarine/marine sedimcnlation on Barentsoya and Sci. Rer,. 12. 86!873. Edge@ya,casrcrn Svalbard. LUNDeUA Rep. -i5. 6l_113. Fairbanks. R. G. l9li9: A 17.00(lvear sca level Lefauconnicr. €llacio-eustatic B. & Itagcn, J. O. l99l: Surging and calving record: influencc of glacial melting rates on the younger ,t glaciers in eastcrn Svalbard. Norsk polarinst. Medtj. I 16. Drvas cvent and deep-ocean circulation. Nature 342.63i, I 30. 612. Lehman. S. J. & Forman. S. L. 19117:Glacier cxtcnt and sed .Fevling-llanssen. R. W. 196-5:Shorelinc displacement in central level variation during the Latc Wcichsclian on northwesr Vcstspitsbergcn and a marinc section from the Iloloccn, Spitsbergen. Polur Res.5. 27 l-272. of'Iafavcra on Barcntsovain Spitsbergen.Norsk polurinst. Lehman. S. J. & Forman. S. L. 1992:Latc Wcichsclianglacicr Medd.9-1.1 31. retreat in Kongsfjorden. wcst Spitsbergen. Svalbard. lFjcldskaar. eaal. W. l9u9: Rapid eustatic changes-ncvergloballl, Rcs. -17. 139-1-5,1. uniform. Pp. 13 l9 (cd): in Collinson. J C.orrelationin Ht.dro_ Mangerud. J. & Gullikscn. S. 1975: .I Apparcnt radiocarbon curbort Exploration. Norwcgian pctrol. Soc.. Graham & rot_ ages of Recent marine shells from Norwav. Spitsbercen and man. London. Ellesmerc Island. ?ecl. Res. -i. 263 273. lrlctchcrlll. C. ll.. Fairbridge. R. W.. Moller. J. J. & Long. Mangerud. J. & Svcndscn. J. l. 1992:Thc last intcrslacial_ A. J. 1993: Emcrgcncc of thc Varanger pcninsula. Arctic glacialpcriod on Spitsbergcn.Svalbard. euat. Sci.I?eo. I I. Nrrrwar'. and climatc changessince dcglaciation. The Hol_ 633 664. ocene.l. ll6-l)7. Mangcrud.J. , Bolsrad.M.. Elgersma. A.. Ilelliksen. D.. Land_ []orman. S. L. 199():Post-glacial relativc scit-lcvelhistorv vik. of J. Y.. Lonnc. L. Lvcke.A. K.. Sali,igscn.O.. SandahL. rrorlhwcstcrnSpitsbcrgcn. Svalbard. Geol. So<..Am. Bull T. 'I-hc & Svendsen.J. L l992a: lasr glacial ntaximum on 101.151t01590. Spitsbcrgen.Svalbard. euot. Iles.-1.t. l_31. Iiormtn. S. L.. Mann. D. H. & Miller. G. IL l9t7: Latc Mangcrud. J.. Bondcvik. S.. Ronncrt. L. & Salvigscn.O. Wcichsclianand I Ioloccnc rclativc sca levcl historvof Br(tg 1992b: Shore displaccmcnt and marinc limits on Eclgcr'tvaand gcrhafvova.Spirsbcrlcn. Res.lZ. .11--50. Barentsoya. Quar. casternSvalbard. LUNDeUA nr7.f.i. Sf f,fl. liormirn. S. L.. t-ubinski.D.. Millcr. G. H.. Snvdcr. J.. Miller. G. H. 19112:Quaternarv dcpositional cpisodcs. rvcstcrn ( V.rtrrh,,r. i.. Korrun. S Ct Mr.lrrcr.. \ lq')5: p;\lsli,ciirl Spitsbcrtcn. Norwar': Aminostraticraphvand glacialhiston . cmcrgcncc ancl distribution of Latc Wcichsclian icc_shccr ArLr. Al1, RA. /J. 1l j .t-ltr loads in thc northcrn Barcnts and Kiira sctrs-Russia. Geol Pirazzofi. P. A. I99l: World atlus ol'Holotene seu_lcoel<.huuge.s 2.1.t1-r ll6. Elscricr Sciencc PublishcrsB.V.. (ilascr. Amstcrdarn. -300. L,'. i96E: Jungc Landhcbung im umkrcis dcs Stortlorci Rcincck. IL E. & Singh. l. B. 1980:Depo.sitional Setlinteutsrt. (SO-Spitsbcrgen). Wtirzburgar Geographisthe Arbeiten 22 Enuironnrents.Springer-Vcrlag. Bcrlin Hcidelbcrg. 5:19pp. il.12. Salvigscn.O. l97tt: Holoccne cmerqcnccand flntlsof pumicc. Ciullikscn. S. 191'10: lsotopic fract ionation of Norwcgirn matcrial whaleboncsand driflu'ood at Svartknausllva.Nordausllan_ Inr radiocarbon ,J.:r.ine.Rudiocarbon ll. 91t0 9u6. dct. \',rr,( Poluritttt. Arhok lv--. ll- llu. Fliiggblon. A. 19tl: Driftw,oodas an indicator ol sea icc Salvigsen. con- O. l9til: Radiocarbondated raiscclbcachcs in Kono ditions. (;?.rgr(. - Ann. h|A. ,\l-94. Karls Land. Sialbard. and ((,nscqucnce\ thcir trrr r6" *,.,a Hjort. C.. Mangcrud. J.. Adriclsson. L.. Bondevik. S.. hrstorvof thc lJarcntsSc:r arca. ()eogr. Ann.6.i/. l8l-292. l.andvik. J. Y. & Salvigsen.O. 1995: Radiocarbon dated Sahigscn. O. 198.1:C)ccurrcncc of pumicc on raiscclbcachc: conrmon musscls M-rtllas edulis tront eastcrn Svalbard and and Ilolocene shorclinedisplaccmcnt in thc inncr lsfjorrlcn lhc Holocenc marine clinatic optimum. Polar Res.1l(2), area. Svalbard.l'olur Res.,2n.s.. 107 1li. 2.39 213. Salvicscn.O. & Osterholm. 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J. 1993: Extended database and 196 + 112 pp. revised CALIB radiocarbon calibration program. Radiocar- Schytt, V., Hoppe, G.. Blake Jr. W. & Grosswald. M. G. 1968: bon 35 , 215-230 The exlenr of thc Wiirm glaciation in the Europcan Arctic. Zale, R. & Brydsten. L. 1993: The pre-flolocene marine limit Int. Assoc. Sci. Hydrol. 79,207-216. on Hopen, Svalbard. Boreas 22,159-16'1 Stubdrup, O. 1992: Sen- og postglaciale sedimenterfra Vis- og Osterholm, H. 1990: The late Weichselian glaciation and Hol- Rtdderialen, Edge@ya,Sualbard. Unpublished thesis, Uni- ocene shore displacement on Prins Oscars Land, Nor- versity of Aarhus. 247 pp. daustlandet, Svalbard. Geogr. Ann. 72A,301-317.