The Young Bal tic advance in the west ern Bal tic de pres sion
Hans-Jürgen STEPHAN
Stephan H.-J. (2001) — The Young Bal tic ad vance in the west ern Bal tic de pres sion. Geol. Quart., 45 (4): 359–363. Warszawa.
The last Weichselian gla cial ad vance into the west ern Bal tic de pres sion, the so-called “Young Bal tic” gla cier ad vance is de scribed. In the south ern Bal tic de pres sion, ice masses flowed west wards and fanned out in the west ern Bal tic re gion where they ter mi nated along the end mo raines of the East Jutland ad vance (Den mark), Sehberg ad vance (Schleswig-Holstein) and Mecklenburg ad vance (Mecklenburg-Vorpommern). The west ward ice ad vance is likely due to the rapid melt ing of Nor we gian and Swed ish ice masses which had pre vi ously blocked the more east erly ice masses from drain ing to the west and north-west. The de po si tion of a purely east ern-sourced de bris fa cies by a Bal tic ice stream in the far west might be the re sult of ice/bed sep a ra tion dur ing flow.
Hans-Jürgen Stephan, Landesamt für Natur und Umwelt des Landes Schleswig-Holstein, Ham burger Chaussee 25, 24220 Flintbek, Ger many, e-mail: h-j.stephan@freenet.de (re ceived: March 20, 2001; ac cepted: May 31, 2001).
Key words: Palaeo-ice stream, Bal tic de pres sion, Weichselian, till fa cies, ice flow.
INTRODUCTION
The term “Bal tic ice” is used by Dan ish ge ol o gists (e.g.
Andersen, 1945; Berthelsen, 1973; Houmark-Nielsen, 1985) to describe a gla cier mainly sourced in north ern Scan di na via and which, flow ing south wards, passed the Bal tic de pres sion be - tween Swe den and the Bal tic States, as reflected by the com po - si tion of its drift. A high pro por tion of Pa laeo zoic lime stone de rived from rock out crops on the bot tom of the Bal tic Sea, es - pe cially around the is lands of Gotland and Öland, is typical. A
“Cen tral Bal tic”drift (or fa cies) is ad di tion ally typ i fied by dis - tinctive do lo mite and crys tal line rock clasts from the is lands of
land and their north ern and south ern vi cin ity, and an “East Bal tic” drift by abun dant do lo mite and land rocks. Yet an - other fa cies oc curs, with predom i nat ing east Swed ish crys tal - line rocks to gether with Palaeozoic lime stones and locally also some dolomites. This fa cies prob a bly orginated from an ice stream along the pres ent Swed ish coast or — if con tain ing dolomites and cen tral Swed ish rocks — from a con flu ence of con trib u tory ice streams from the Swed ish up lands with the Cen tral Bal tic main stream. I pro pose the term “Svecobaltic”
for this com po si tion.
In most Bal tic fa cies sig nif i cant amounts of Pre cam brian red-vi o let sand stones (Jotnian Sand stone or NexÝ-Sand stone, Ta ble 1) are also found (cf. Schuddebeurs, 1981).
The term “Young Bal tic” is used for the last Weichselian gla cier ad vance reach ing Den mark and Schleswig-Holstein, in con trast to an early Weichselian, the “Old Bal tic” and the lat est Saalian, the “palaeobaltic” ad vance.
THE YOUNG BALTIC GLACIATION
In Den mark the Young Bal tic ad vance is sep a rated into two (or three) in di vid ual phases. The old est reached the East Jutland mar ginal line, the next (the Belt Sea ad vance) reached a line cross ing the Flensburg fjord, the is land of Funen and then fol lowed a line north of the Great Belt and Sealand. A third and last ac tive phase in the West Bal tic area had its mar gin along the Darßer Schwelle, the thresh old in the Bal tic Sea be tween North Mecklenburg and the is land of Falster. Fur ther to the north it em braces the Fakse Bight, the KÝge Bight, the south ern part of the resund, and the south-westernmost area of Skane (Smed, 1994).
In North Ger many the gla cial mar gins are lo cally un cer tain or dis puted. A con nec tion of the East Jutland line with the Pom - er a nian line as long sug gested by many ge ol o gists (e.g.
Sjörring, 1981; Stephan, 1994) has been re jected by oth ers on the ba sis of clast com po si tion in the tills (Smed and Rühberg, pers. comm.). In Mecklenburg-Vorpommern the W3-ground mo raine wedg ing out north of the Rosenthaler Staffel (Heerdt,
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1965; Cepek, 1967) be longs to the Young Bal tic ad vance, there called the Mecklenburg ad vance (Eiermann, 1984,
“Mecklenburger Sta dium”; Rühberg, 1987; Rühberg et al., 1995). In Schleswig-Hol stein a Young Bal tic till is known, for in stance north of Kiel and at the north ern side of the Eckernförde Bay. It is typ i fied by crys tal line rocks from the is - lands of land (Ta ble 1) and, where unweathered, by abun dant Palaeozoic lime stone clasts and some of do lo mite. It is likely that the Sehberg end mo raine (Stephan et al., 1983) rep re sents the mar gin of the Young Bal tic ice.
YOUNG BALTIC FLOW LINES
Stephan (1994) com piled di rec tions of lo cal ice flow de - duced from fab ric anal y ses and from striations from all coun - tries bor der ing the West ern Bal tic Sea. Most mea sure ments from Den mark, many of them un pub lished, were made avail - able by S. Sjörring, and from Swe den by B. Ringberg. To gether with pub lished in for ma tion (e.g. Rich ter, 1937) and many of my own mea sure ments from Schleswig-Hol stein they pro vided the ba sis for de tailed re con struc tion of flow lines of the Young Bal tic ice (Fig. 1). This ice had its source in north ern Scan di na - via and the north ern Bal tic re gion and, form ing a large ice stream, first flowed along the east ern Bal tic de pres sion south - wards where it ter mi nated in the Pom er a nian up lands. The ice flow then turned west, pass ing the de pres sion be tween South Skane and North Ger many, the main stream flow ing through the “gate” be tween the is lands of Born holm and Rügen. It fanned out in the west ern Bal tic re gion with widely vary ing flow di rec tions: SW-wards from the is land of Rügen to Lübeck Bay (though S-wards around the is land of Poel); W-wards from the is land of Fehmarn to Eckernförde Bay in Schleswig-Hol - stein (with some de flec tions to wards the SW at older land - forms), and from there NW-wards to the Lit tle Belt. Fur ther to the east NNW- to N-di rec tions pre dom i nated in Den mark. In south-west Skane NNE- to NE-di rec tions have been found (cf.
Ringberg, 1988).
MODELLING THE BALTIC ICE STREAM
For more than a cen tury, ge ol o gists have tried to ex plain the dif fer ent com po si tion of tills in Den mark and North Ger many by the ex is tence of dif fer ent ice streams in gla ci ated Scan di na - via. Early ob ser va tions and in ter pre ta tions were made by De Geer (e.g. 1888, tab. 2 with a Bal tic gla cier ad vance in the west - ern Bal tic de pres sion) and Gottsche (1883).
Zeise (1889) and Madsen (1898), from their stud ies of the
“Bal tic mo raine gir dle”, in ferred re peated glaciations with Bal - tic (E–W flowing) ice masses sep a rated by ice from the north.
Torell (in: Zeise, 1889) ex plained the E–W flow di rec tion by de flec tion of the nor mally south wards mov ing ice mass at the up lands at the south ern mar gins of the Bal tic de pres sion and then by the flow of the ice along this de pres sion to wards the W.
This con cept was repeated by Gripp (1981).
Eissmann (1967), Woldstedt and Duphorn (1974) and oth - ers later ex plained the dom i nance of Bal tic ice masses dur ing the late phases of glaciations by a shift of the ice shed or the main ice ac cu mu la tion cen tre (ice dome) in Scan di na via from W to E. Such a shift was first men tioned by Enquist (1918), then pos tu lated by Ahlmann et al. (1942) and Ljunger (1943).
Zeise (1889) thought N–S ice flow to be re stricted to the time of max i mum gla ci ation in Scan di na via, pre ceded and fol lowed by E–W flow along the Bal tic de pres sion. This fun - da men tal model was mod i fied by Wennberg (1949). He ex - plained the late Bal tic ice stream by turn ing of the pri mary main flow within the Scan di na vian ice shield, due to the de cay of the Sm¯land- and the Dalarna-ice dur ing the melt phase.
Bal tic ice masses should there fore have dis placed cen tral and
Rock type Quan tity
land Aplitgranite 1
Other land rocks 28
Red Bal tic Sea Quartz Por phyry 8 Brown Bal tic Sea Quartz Por -
phyry 2
Bal tic Sea Diabase 1
Garberg Por phyry 1
Red Växjö Gran ite 12
Grey Växjö Gran ite 1
Virbo Gran ite 6
Sala Gran ite 3
Uppsala Gran ite 1
Oskarshamn Gran ite 2
Born holm Gran ite 1
Rhombe Por phyry 1
Hardeberga Sand stone 1
Chiasma Sand stone 1
NexÝ Sand stone 14
TGZ: λ 17.62°/ϕ 57.49°; TGZ — Theoretisches Geschiebe-Zentrum (the o ret i cal center of in di ca tor rocks; Lüttig, 1957); λ — lon gi tude, ϕ — latitude
T a b l e 1 Clasts indic a tive of prov e nance re cov ered from
the decalcified sur face of the Young Bal tic till be tween Knoop and Friedrichshof, north of
Kiel, Schleswig-Holstein, North Ger many, counting by Schlüter, 1998; un pub lished
south Swed ish ice masses in the west ern Bal tic re gion. A very sim i lar idea was pub lished by Stephan (in: Ehlers et al., 1984, melt ing of block ing west ern ice masses). The sim i lar ity with the con cept pro posed by De Geer (1888) is strik ing.
Cur rent understanding suggests that dur ing all larger Pleis - to cene glaciations or sta dia there were likely cy clic changes of the main ice streams within the Scan di na vian ice shield: N–S to ra dial ice flow dur ing the ice max ima and a dom i nance of Bal - tic ice masses dur ing the late phases of glaciations. The o - retically con di tions occurring dur ing the late phases (ice dome ac cu mu la tion in the NE) should have ex isted also dur ing the very early phases. Ev i dence for this view is the ex is tence of the Early Weichselian “Old Bal tic” till (e.g. Andersen, 1945). No such early Bal tic tills are known from older glaciations, per - haps be cause of ero sion of such tills dur ing the fol low ing main glaciations.
Dis cus sion con cern ing the be hav iour of the E–W ice stream still con tin ues. The strik ing com po si tion of “red tills”
(cf. Kabel, 1982; Ehlers, 1992; Stephan, 1998) has been ex - plained by an en gla cial trans port of East Bal tic ma te rial, not mixed with other ma te rial from the gla cier sole be tween the source area and the gla cier mar gin (e.g. Ehlers, 1981;
Schuddebeurs, 1981). Move ment over large fields of “dead ice” of the pre ced ing gla ci ation phase with out con tact with the ground may also be an ex pla na tion for the more or less pure East Bal tic till fa cies found in the west (Woldstedt and Duphorn, 1974). A mod i fied ver sion of this mech a nism was pro posed by Müller et al. (1997) who be lieve that the Young
Bal tic ice — be cause of the strik ing lack of a till de posit — was mov ing over a frozen ice-dammed lake in front of the Wismar Lobe.
But move ment over un frozen wa ter-oversaturated sed i - ment or even over a wa ter film is also a pos si bil ity. The first of these mech a nisms is dis cussed by Boulton and Jones (1979). In their the ory of such “de form able bed” con di tions the ice could have been mov ing rap idly over a steadily and strongly de form - ing bed with lit tle fric tional re sis tance. In the sec ond case the ice could have rap idly slid over a wet base with no or lit tle con - tact with the ground (ice/bed-separation, Shaw and Kvill, 1984), an idea al ready pub lished by Tyn dall and Thomson (in:
Haas, 1890; cf. Rich ter, 1937). Piotrowski and Kraus (1997) and Piotrowski and Tulaczyk (1999) pos tu lated this for the last ice sheet in north west ern Ger many. Such be hav iour of the ice sheet in the Bal tic de pres sion is all the more likely since the ice flow fol lowed the main (melt) wa ter dis charge to wards the Kattegat, Skagerak, and the Nor we gian Trough. This move - ment could have oc ca sion ally cul mi nated in a surge.
The strong fan ning out of the Young Bal tic ice in the west - ern Bal tic re gion into older gla cial de pres sions and the de po si - tion of a com monly strik ingly thin till bed could be ad di tion ally sup ported by the de vel op ment of proglacial ice-dammed lakes be tween the gla cier front and mar ginal up lands that were sub - se quently over rid den (“overslid”) by the ice. The fre quent ob - ser va tion of thin glaciolacustrine sed i ments at the base of Young Bal tic tills in the east of Schleswig-Holstein fits well with this ex pla na tion.
REFERENCES
AHLMANN H. W., LAURELL E. and MANNERFELT C. (1942) — De norrländska landskapet särskilt dess topografiska och kvatärgeoliska utveckling: 1–50. 1 kt. Ymer.
ANDERSEN S. A. (1945) — IsstrÝmmenes retning over Danmark i den sidste istid, belyst ved ledeblokundersÝgelser. Medd. Dansk Geol.
Fören., 10: 594–615.
BERTHELSEN A. (1973) — Weichselian ice ad vances and drift suc ces - sions in Den mark. Bull. Geol. Inst. Univ. Uppsala, 5: 21–29.
BOULTON G. S. and JONES A. S. (1979) — Sta bil ity of tem per ate ice caps and ice sheets rest ing on beds of de form able sed i ment. J.
Glaciol., 24: 29–43.
CEPEK G. (1967) — Stand und Probleme der Quartärstratigraphie im Nordteil der DDR. Ber. Dtsch. Ges. Geol. Wiss., A, Geol. Paläont., 12 (3/4): 375–404.
DE GEER G. (1888) — Om Skandinaviens niv¯förändringar un der qvartärperioden. Geol. Fören. Stock holm Förhand., 10 (5): 366–378.
EHLERS J. (1981) — Some as pects of gla cial ero sion and de po si tion in North Ger many. Ann. Glaciol., 2: 143–146.
EHLERS J. (1992) — Or i gin and dis tri bu tion of red tills in North Ger many.
Sver. Geol. Unders, Ser. C, 81: 97–105.
EHLERS J., MEYER K.-D. and STEPHAN H.-J. (1984) — The pre-Weichselian glaciations of North-West Eu rope. Quatern. Sc. Rev., 3: 1–40.
EIERMANN J. (1984) — Ein zeitliches, räumliches und genetisches Modell zur Erklärung der Sedimente und Reliefformen im Pleistozän gletscherbedeckter Tieflandsedimente — Ein Beitrag zur Methodik der mittelmaßstäbigen naturräumlichen Gliederung. In:
Umweltforschung. Zur Ana lyse und Di ag nose der Landschaft (eds. H.
Rich ter and K. Aurada): 169–183. H. Haack. Gotha.
EISSMANN L. (1967) — Rhombenporphyrgeschiebe in Elster und Saalemoränen des Leipziger Raumes. Abh. Ber. Naturkund. Mus.
Mauritianum Altenbg., 5: 37–46.
ENQUIST F. (1918) — Die glaziale Entwicklungsgeschichte Nordwestskandinaviens. Sver. Geol. Unders, Ser. C, 12 (285):
1–143.
GOTTSCHE C. (1883) — Die Sedimentärgeschiebe Schleswig-Holsteins 1–66. Yo ko hama.
GRIPP K. (1981) — Der Ablauf der Würm-Vereisung in der Senkungszone am Südrand Skandinaviens. Meyniana, 33: 9–22.
HAAS H. J. (1890) — Betrachtungen über die Art und Weise, wie die Geschiebemergel Norddeutschlands zur Ablagerung gelangt sind.
Mitt. Miner. Inst. Univ. Kiel, 1: 111–136.
HEERDT S. (1965) — Zur Stratigraphie des Jungpleistozäns im mittleren N-Mecklenburg. Geologie, 14 (5/6): 589–609.
HOUMARK-NIELSEN M. (1985) — Pleis to cene stra tig ra phy and gla - cial his tory of Cen tral Den mark. Bull. Geol. Soc. Den mark, 36, 1–189.
KABEL C. (1982) — Geschiebestratigraphische Untersuchungen im Pleistozän Schleswig-Holsteins und angrenzender Gebiete. Dis ser ta - tion Univ. Kiel, 231 S, Anhang 47 S. Kiel.
LJUNGER E. (1943) — Isdelarstudier vid polcirkeln. Geol. Fören.
Stock holm Förhand., 65: 198–210.
LÜTTIG G. (1957) — Geschiebezählungen als Hilfsmittel für die Erforschung des Eiszeitalters und seiner wirtschaftlich wichtigen Lagerstätten. Umschau 1957, 13: 403–405.
MADSEN V. (1898) — Om indelingen af de danske kvart³rdannelser.
Medd. Dansk Geol. Fören., 5: 1–22.
MÜLLER U., RÜHBERG N. and SCHULZ W. (1997) — Die Wismar-Bucht und das Salzhaff — geologische Entwicklung und Küstendynamik. Meer und Mu seum, 13: 17–24.
PIOTROWSKI J. A. and KRAUS A. (1997) — Re sponse of sed i ment to ice sheet load ing in north west ern Ger many: ef fec tive stresses and gla - cier bed sta bil ity. J. Glaciol., 43: 495–502.
PIOTROWSKI J. A. and TULACZYK S. (1999) — Ice-bed sep a ra tion and en hanced basal slid ing un der the last ice sheet in north-west Ger many?
Quatern. Sc. Rev., 18: 737–751.
RICHTER K. (1937) — Die Eiszeit in Norddeutschland. Borntraeger.
Berlin.
RINGBERG B. (1988) — Late Weichselian ge ol ogy of south ern most Swe - den. Boreas, 17: 243–263.
RÜHBERG N. (1987) — Die Grundmoräne des jüngsten Weichsel-Vorstoßes in der DDR. Z. Geol. Wiss., 15: 759–767.
RÜHBERG N., SCHULZ W., von BÜLOW W., MÜLLER U., KRIENKE H.-D., BREMER F. and DANN T. (1995) — Mecklen - burg-Vorpommern. In: Das Quartär Deutschlands (ed. L. Benda):
95–115. Borntraege. Berlin.
SMED P. (1994) — Steine aus dem Norden: Geschiebe als Zeug en der Eiszeit in Norddeutschland. Borntraeger. Berlin.
SCHUDDEBEURS A. P. (1981) — Die Geschiebe im Pleistozän der Niederlande. Der Geschiebesammler, 15: 73–90, 137–157.
SHAW J. and KVILL D. (1984) — A glaciofluvial or i gin of drum lins of the Living stone Lake area, Sas katch e wan. Can. J. Earth Sc., 21:
1442–1459.
SJÖRRING S. (1981) — The Weichselian till stra tig ra phy in the south ern part of Den mark. Quatern. Stud. Po land, 3: 103–109.
STEPHAN H.-J. (1994) — Der Jungbaltische Gletschervorstoß in Norddeutschland. Schr. Naturwiss. Ver. Schlesw.-Holst., 64: 1–15.
STEPHAN H.-J. (1998) — Geschiebemergel als stratigraphische Leithorizonte in Schleswig-Holstein; ein Überblick. Meyniana, 50:
113–135.
STEPHAN H.-J., KABEL C. and SCHLÜTER G. (1983) — Strati graphi - cal prob lems in the gla cial de pos its of Schleswig-Holstein. In: Gla cial De posits in North-West Eu rope (ed. J. Ehlers): 305–320. A. A.
Balkema. Rot ter dam/Brookfield.
WENNBERG G. (1949) — Differentialrörelser i Inlandsisen sista Istiden i Danmark, Sk¯ne och Östersjön. Medd. Lunds Geol. Miner. Inst., 114, 1–201.
WOLDSTEDT P. and DUPHORN K. (1974) — Norddeutschland und angrenzende Gebiete im Eiszeitalter. K. F. Köhler. Stuttgart.
ZEISE O. (1889) — Beitrag zur Kenntnis der Ausbreitung, sowie besonders der Bewegungsrichtung des nordeuropäischen Inlandeises in diluvialer Zeit: 1–65. In au gu ral-Dissertation, Albertus-Universität.
Königsberg. Preußen.
