Geology of sub-Quaternary basement and stratigraphy of Quaternary sediments in the Middle Notec River valley

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Annales Societatis Geologorum Poloniae (1997), vol. 67: 57—81.

GEOLOGY OF SUB-QUATERNARY BASEMENT AND STRATIGRAPHY OF QUATERNARY SEDIMENTS IN THE MIDDLE NOTEĆ RIVER VALLEY, WESTERN POLAND

Jan DZIERŻEK

Institute o f Geology, U niversity o f Warsaw, Ż w irki i W igury 93, 02-089 W arszaw a

Dzierżek, J., 1997. Geology o f sub-Quaternary basement and stratigraphy o f Quaternary sediments in the Middle Noteć River valley. Ann. Soc. Geol. Polon., 67: 57-81.

A bstract: A model of geological structure, including detailed stratigraphy o f Quaternary sediments in the Middle Noteć River valley region, is presented. More than 950 boreholes and 64 geological sections have been analysed.

The sub-Tertiary basement includes the Pomorze-Kujawy (Pomeranian-Kuyavian) Swell and the Szczecin- Mogilno Trough, built up o f Cretaceous and Jurassic rocks. The Tertiary sediments are up to 260 m thick. Fourteen till beds, representing 7 glaciations: Narevian, Nidanian, Sanian I, Sanian II, Odranian, Wartanian, and Vistulian, have been distinguished, ranging from a few to 220 m in thickness. Fluvial and lacustrine sediments separating individual tills represent the Podlasian, Malopolanian, Ferdynandovian, Mazovian, Lubavian and Eeinian inter

glacials.

A bstrakt: Przedstawiono model budowy geologicznej rejonu Doliny Środkowej Noteci wraz ze szczegółową stratygrafią osadów czwartorzędowych, uzyskany z analizy ponad 950 wierceń i 64 przekrojów. W podłożu trzeciorzędu występują tu głównie skały jury i kredy, wchodzące w skład walu pomorsko-kujawskiego i niecki szczecińsko-mogileńskiej. Ukształtowanie podłoża osadów trzeciorzędowych wykazuje zgodność z budową struktur tektonicznych. Osady trzeciorzędu w rejonie Doliny Środkowej Noteci mają miąższość od kilkunastu do 265 m. W bezpośrednim podłożu osadów czwartorzędowych występują osady miocenu i pliocenu. Wśród osadów czwartorzędowych mających tu miąższość od kilku do 220 m wyróżniono 14 warstw glin lodowcowych repre

zentujących 7 zlodowaceń: Narwi, Nidy, Sanu I i II, Odry, Warty i Wisły. Wyróżniono także osady rzeczne i jeziorne interglacjałów: podlaskiego, małopolskiego, ferdynandowskiego, mazowieckiego, lubawskiego i eem- skiego.

Key words: sub-Quaternary basement, Quaternaiy stratigraphy, Noteć River valley, western Poland.

Manuscript received 7 March 1995, accepted 20 February 1997

INTRODUCTION

T he aim o f this p ap e r is to present Q uaternary stratigra

phy and palaeogeography o f th e M iddle N oteć R iver valley on th e background o f geological structure o f that region.

The principal m ethod applied in this study, consisting in an analysis o f borehole data, has a num ber o f draw backs that result from the quality, quantity, spatial distribution and re

liability o f th e data, as w ell as from subjective interpretation procedures. Som e o f p resented conclusions w ould, th ere

fore, require further verification.

STATE OF RESEARCH

G eological and geom orphological problem s o f the study area have been d ealt w ith in num erous papers w hich can be subdivided into three groups:

1. papers related to geological structure o f th e M esozoic substratum : Pożaryski (1956, 1979), D adlez & D em bow ska (1963, 1965), D adlez (1973, 1974, 1980), C ieśliński & Jas- kow iak (1973), D adlez & M arek (1974), Jóźw iak & M ły

narski (1984);

2. papers discussing T ertiary sedim ents: C iuk (1955, 1970), G adom ska (1957), C iuk & P o żary sk a (1982), D yjor

& Sadow ska (1986), P iw ocki & O lchow icz-P aprocka (1987), D yjor (1992), P iw ocki (1992); and

3. papers dealing w ith geom orphology and Q uaternary geology. The earliest studies focused m ainly on the origin o f the T o ru ń -E b ersw ald e ice-m arginal valley, as w ell as on the origin and age o f m orainic ridges (M aas, 1904; K eilhack, 1904; Korn, 1916; Lencew icz, 1926; G alon, 1929, 1961a, b, 1968a, b, 1969; W oldstedt, 1932). O ne can n o t exceed the im portance o f K ry g o w sk i’s (1952, 1953, 1956a, b, 1961a, b, 1962, 1972, 1975) w ork, w ho w as frequently d iscussing the area in question w hen describing the m orphology and geo-

8 — Annales...

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J. DZIERŻEK

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F ig . 1. G e o m o r p h o lo g ic a l sk e tc h o f the stu d y area (b a sed o n K r y g o w sk i, 1956a; K ozar- sk i, 1962a; L istk o w sk a &

M ak siak , 1977; U n ie je w sk a &

W ło d ek , 1 978; K on d rack i, 19 7 8 ). 1 - m o ra in ic p la te a u s, 2 - o u tw a sh p la in s, 3 - v a lle y b o tto m s, 4 - d u n e fie ld s, 5 - en d m o ra in es, 6 - e le v a tio n p o in ts, 7 - rivers and la k es, 8 - b ou n d aries o f p h y sio g ra p h ic units; W .L . - W a łc z L ak e D is  trict. K .L . - K rajna L ak e D is  trict, C H .L . - C h o d z ie ż L ake D istrict

logical structure o ft h e W ielk o p o lsk a Lowland. From am ong num erous papers by K ozarski (1 9 5 9 , 1962a, b, 1965, 1980, 1981, 1988, 1991, 1992, 1993, 1995) and his team (K ozar

ski & R otnicki, 1978; K ozarski e t a l., 1980; K asprzak &

K ozarski, 1989; K asprzak, 1985, 1991, 1992; Kasp-rzak &

K ozarski, 1992a, b, c; K ozarski & Kasprzak, 1992), the fo l

lo w in g co n clu sio n s can b e drawn:

- the area o f W ielk o p o lsk a L ow land d oes not bear e v i

den ce in favour o f the p resen ce o f an icesh eet before the V istulian m axim um stadial;

- the L eszn o P hase (2 0 ,0 0 0 yrs B P) left o n ly one bed o f lod gem en t till, several m etres thick;

- the till hitherto associated w ith the transgression o f the Poznań Phase icesh eet (1 8 ,8 0 0 yrs B P) is, in fact, an abla

tion co v er dep osited during the recessio n o f the m axim um phase o f the glaciation;

- a short-term ad van ce during the C h od zież sub-phase (1 7 ,7 0 0 yrs B P ) left, apart from frontal m orainic ridges, a separate lod gem en t till bed; and

- the N o te ć -W a r ta ice-m arginal v a lley w as active b e

tw een the C h o d zież sub-phase and the Gardno Phase (1 4 ,5 0 0 yrs B P ), w hen the feed in g by m eltin g waters from the north w as term inated.

S o m e o f the a b o v e co n clu sio n s have been fu lly co n  firm ed in this paper.

GEOMORPHIC SETTING

The study area is co v ered b y 4 sheets o f 1:100,000 top o

graphic m aps: Piła, W yrzysk , C zarnków and W ągrow iec, attaining 3 ,6 0 0 sq. km. From the physiographic poin t o f

v iew , the area in question in clu d es, apart from the M iddle N o te ć R iver v a lle y (F ig. 1) and the eastern part o f the G o

rzów B asin, b elo n g in g to the T o ru ń -E b ersw a ld e (N o t e ć - Warta) ice-m arginal v a lley , the fragm ents o f W a łcz Lake D istrict, G w da R iver v a lley , Krajna Lake D istrict (on the north) and C h od zież Lake D istrict (on the south).

The M iddle N o te ć R iver v a lle y is the lo w e st-e le v a te d area, b ein g characterised by high and very steep v a lley sid es and flat, broad bottom , up to 10 km w id e. W ithin the v a lley , a number o f erosion-accum ulational terraces and a flo o d - plain, built up m o stly o f peat (G alon , 1961a, b), can be d is

tinguished. T he W a rta -N o teć interfluve sh o w s cla ssica l ae- olian landscape features (S tan k ow sk i, 1963; K ozarski,

1962b; K lim ko, 1973).

T he N W part o f the study area com p rises the W ałcz Lake D istrict, also called the W a łcz Plateau, w h ich can be subdivided into the R óża H ills and Trzcianka Plain (K ry

g o w sk i, 1956a). T he R óża H ills is a ty p ica l m oraine plateau, com p osed c h ie fly o f tills (L istk ow sk a & M aksiak, 1977;

L istkow ska e t a l., 1978), overtopped by h ills up to 207.1 m a.s.l. w hich are separated by ic e -m e lt kettles. T he low er- situated Trzcianka Plain (up to 96 m a .s.l.) is less strongly d issected and com p osed m o stly o f last g lacial flu v io g la cia l sed im en ts (Fig. 1). T his plain reveals sm all th ick n esses o f Quaternary sedim ents, underlain b y sh a llo w ly subcropping Tertiary deposits (L istk ow sk a e t a l., 1978).

The G w da R iver v a lley is a distinct d epression form ed during the recession o f the P om eranian P hase o f the V is  tulian G laciation. C lo se to its m outh to the N o te ć R iver, the v a lley b eco m es broader and form s the U jśc ie B asin.

The Krajna Lake D istrict w ith in the area studied is a plateau that bears num erous m orainic ridges, like D ęb o w a

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QUATERNARY SEDIMENTS IN THE NOTEĆ RIVER VALLEY

59

Góra (1 9 3 .7 m a.s.L), R ząd k ow o (1 8 6 .7 m ), W olsk o (1 6 1 .2 m ), Góry W y so k ie (1 5 5 .8 m ), and B rzozow a Góra (1 3 9 .4 m ), w h ich originated during the recession o f the Poznań Phase o f the last glaciation , interrupted by several o sc illa  tion s (S zu p ryczyń sk i, 1958, 1961; G alon, 1961a, b; Kozar- ski, 1962a).

T he h igh est-elevated part o f the C h od zież Lake D istrict, i.e. C h o d zież H ills (G o n ty n iec 191.5 m a .s .l.) and C zarnków H ills (1 2 5 .7 m a .s.l.), represents a zo n e o f frontal m orainic ridges that extends alo n g the southern margin o f the ice- m arginal v a lley . To the south, a m onotonous W ągrow iec Plain ( 7 0 - 9 0 m a .s.l.) occu rs, b ein g covered in large part by outw ash sed im en ts d ep o sited during the recession o f the Poznań P h ase o f the V istu lian . Its surface is dom inated by num erous finger lakes.

METHODS

T his study is based on an an alysis o f m ore than 9 50 drill cores c o llected in the A rch iv es o f B oreh oles and G eo lo g ica l D ocu m en tation , P olish G eo lo g ica l Institute in W arsaw (c a . 60% ), as w e ll as those stored in archives o f the G eo lo g ica l Enterprise (P rzed sięb iorstw o G eo lo g ic z n e ) in Poznań, V o i- vodship C ou n cil (U rząd W o jew ó d zk i) in Piła, Quaternary sand pit in U jśc ie (together c a . 5% ), and th ose derived from the B o reh o le D ocum entation A rch ive, sheets Poznań (K ry

g o w sk i, 1953) and B y d g o sz c z (A d a m iec-C h o d k iew iczo w a , 1962) o f the D etailed G eo lo g ica l Map o f Poland, 1:50,000.

T he distribution o f b oreh oles drilled in the study area is unequal (F ig. 2); m ost o f them have been drilled in the w e st

ern part (brow n coal d ep osits at Trzcianka) and w ithin large cities (P ila, C h o d zież, C zarnków , W ągrow iec, R o g o źn o , W yrzysk ). D ifficu lties in g e o lo g ic a l interpretation m ay result not only from the lack o f su fficien t num ber o f b oreholes, but also from their e x c e s s iv e concentration in so m e areas. In poorly docu m en ted areas the in

ferred g e o lo g ic a l m od els appear to be sim ple, w hereas in d en sely drilled region s - m uch more com p licated.

B a sin g on b orehole lo g s, 64 g eo lo g ica l cross sectio n s o f d ifferent length have been constructed (F ig. 2). W hen ch o o sin g cross s e c  tion lines, both the num ber o f b oreholes and the orientation o f linear m orp h ological elem ents and sub-Q uatem ary structures have been taken into accou n t (F igs. 1, 3). O riginal cross section s have been prepared on th e 1 :25,000 horizontal and 1 :1,000 vertical sca les. The ch o ic e o f scale w as im portant in areas o f high borehole co n  centration, m aking it p o ssib le to present even several tens o f centim etres thick beds. R ela

tiv ely sm all vertical exaggeration o f 25:1 pre

vents artificial den ivelation s o f beds that w ould result in erroneous estim ation o f tectonic proc

esses.

L ith ological properties enabled the subdi

v isio n o f a b orehole lo g into individual beds o f groups o f beds. S p ecial attention has been paid

to stratigraphie boundaries, particularly that b etw een the Tertiary and Quaternary. L ogs o f neighbouring boreholes have then been correlated w ith each other on the basis o f li- th ological sim ilarities (grain siz e , m ineral and pétrographie com p osition , C aC0 3 content, p resen ce o f clasts o f S can d i

navian provenance, occurrences o f m icas, g la u co n ite and coal silt, colour, degree o f com p actn ess, etc.) and h yp som et

ric position. The quality o f b orehole lo g descriptions is vari

able; the best on es refer to b oreh oles drilled for groundw ater and brown coal prospection, sin ce th ey in clu d e the w h o le section o f Quaternary sedim ents and are u su a lly fairly d e

tailed. D eep b oreh oles (several hundred m etres) bear abun

dant docum entation, although the description o f Quaternary and Tertiary sedim ents is u su ally sim p lified .

In ca se o f drastic d ifferen ces in the description o f n eig h  bouring logs, reinterpretation o f lith o lo g ica l characteristics w as necessary. Interpretation o f lo g s o f origin ally h o m o g e

neous sedim ents (u su ally tills) c o n sisted in id en tification o f erosion-denudational surfaces found in neighbouring s e c  tions.

Interpretation o f g eo lo g ica l cross section s m ade it p o s

sib le to construct m aps o f the top o f M e so z o ic and the base o f Quaternary d eposits, as w ell as m aps o f th ick n esses o f P aleogen e, M io ce n e and P lio cen e strata. Extrapolated is o li

nes have been corrected for topography by ap p lyin g c lo s e ly - spaced iso h y p ses to high-gradient areas (d eep erosion al d is

sectio n s) or draw ing sem i-circular iso h y p ses in areas a f

fected by g la cio tecto n ic disturbances. T h ese m aps w ere the basis for subsequent p a la eo g eo m o rp h o lo g ica l an alysis.

L ocal stratigraphy o f Quaternary sed im en ts, m ost im  portant in interpretation o f g e o lo g ic a l cross sectio n s, has

F ig . 2 . L o c a tio n o f b o reh o les and g e o lo g ic a l c r o s s-se c tio n s. 1 - b o r e h o le s thai drilled T ertiary strata, 2 - b o r e h o le s that d rilled Q uaternary se d im e n ts, 3 - b o reh o les that did n ot reach th e sub-Q uaternary su rfa ce, 4- g e o lo g ic a l c r o s s-se c tio n s d isc u sse d in the text, 5 - oth er g e o lo g ic a l c r o ss se c tio n s

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F ig . 3 . L o c a tio n o f the stu d y area a g a in st principal g e o lo g ic a l structures (b a sed on D a d le z & M arek, 1974; P ożarysk i, 1979;

J ó źw ia k & M ły n a rsk i, 19 8 4 ). / - b ou n daries o f structural u nits, 2 - p rin cip al fa u lts, 3 - sa lt te c to n ic structures

been estab lish ed accord in g to the fo llo w in g rules:

1. correlated till beds sh ou ld form continuous horizons o f relatively sm oothed b ase, ex cep t g la cio tecto n ica lly -d is- turbed areas;

2. the ranking o f individual till beds should be based on properties o f intervening interglacial sedim ents and occur

rences o f distinct erosion-denudational surfaces;

3. the d eep est b oreh oles (B oru szyn area), docum enting the co m p lete record o f Quaternary ev en ts, and th ose having palaeob otan ic docum entation o f interglacial stages (P iła re

g ion ) are o f key im portance for reconstruction o f the number o f g laciation s in the study area;

4. tills ex p o sed at the groundsurface are older than those o f the Pom eranian Phase o f the last glacial stage;

5. th erm olu m in escen ce datings o f sedim ents ex p o sed in v a lley sid es are on ly supplem entary source o f inform ation, as far as stratigraphy o f yo u n g strata is concerned; and

6. the proposed sch em e o f local Quaternary stratigraphy is confronted w ith those o f neighbouring regions, as w e ll as w ith sch em es o f the Quaternary stratigraphy o f P oland by Lindner (1 9 9 1 a , b, 1 9 9 2 ) and B araniecka (1 9 9 0 ).

GEOLOGICAL SETTING AND SUB-TERTIARY MORPHOLOGY

T he M id d le N o te ć R iver v a lle y is situated at the bound

ary o f tw o large M e so z o ic structures (F ig. 3; cf. Pożaryski, 1956): the P om eran ian -K u yavian S w ell (anticlinorium ) and S z c z e c in —L ó d ź -M ie c h ó w Trough (synclinorium ). T h ese structures trend N W -S E , their boundary b ein g p laced along the intersection o f the base o f U pper C retaceous strata (D a d lez, 1980; Fig. 3). In th e study area o n ly so m e elem en ts o f these tw o structures occur. T he Piła and N ak ło anticlines and the Skórka sy n clin e, b elo n g in g to the P om eran ian - K uyavian S w ell (Fig. 4 ), appear in the northern and central

parts o f the area. T he rem aining parts co v er fragm ents o f the S z c z e c in -Ł ó d ź (M o g iln o ) Trough, in clu d in g the C zarnków graben and Ł ę g ó w sy n clin e that are separated by the Obor

niki elevation , com prising the R o g o źn o and S z a m o tu ly - Oborniki brachyanticlines (D a d lez & D em b o w sk a , 1963;

D ad lez, 1973; Pożaryski, 1979).

T he thickness o f the Z e c h s te in -M e so z o ic co m p lex in that part o f the anticlinorium , drilled at K otuń, S W o f Piła, attains 4 ,1 9 5 m. T he sub-Tertiary substratum is com p osed o f the L o w er-M id d le Jurassic, rarely U pper Jurassic rocks (Fig. 4). The strata bu ild in g the P om eran ian -K u yavian S w ell sh ow in sign ifican t dip v a lu es (D a d le z & D em b ow sk a, 1963).

G eo lo g ica l structure o f th e P om eran ian -K u yavian S w ell is characterised as w ell b y faults that strike both par

allel (N W -S E ) and perpendicular to the structural grain o f this region. From the latter on es, the m ost im portant is the C zarn k ów -T u ch ola (B rodnica) fault, separating the struc

ture into the Pom eranian and K u yavian S w e lls (D a d le z &

M arek, 1974; D ad lez, 1980; Jóźw iak & M łynarski, 1984;

Stupnicka, 1989). Salt tecton ic features are a lso ubiquitous, like those described from W ałcz, Piła, T rzcianka, C h o d zież or W apno areas, situated im m ed iately east o f the study area (D ad lez, 1974).

The thickness o f the P e r m o -M e s o z o ic co m p lex in the S zczecin Trough e x ceed s 7 ,0 0 0 m (P ożarysk i, 1956), that o f C retaceous strata b ein g c a . 2 ,0 0 0 m in the w estern part o f the trough. T he th ick n ess o f C retaceous rocks in th e M o g il

no Trough increases from the O borniki e lev a tio n tow ards SE, w here the Upper C retaceous strata alon e are m ore than 3 ,0 0 0 m thick (D a d lez, 1974). T h ese structures w ere fin ally shaped during the Laramian m o v em en ts, although reduced th ick n esses o f individual M e so z o ic lithostratigraphic m em  bers indicate a step-like, syn sed im en tary uplift o f the w h o le block.

The O borniki elevation originated due to h alotecton ic processes o f variable intensity that w ere a ctive sin c e the Tri

a ssic through C retaceous tim es. T he elev a tio n is uplifted and cut by num erous faults (Stupnicka, 1989).

In the M iddle N o te ć R iver v a lle y region, the top o f M e so z o ic rocks is docum ented by 80 b orehole lo g s (F ig. 4).

T he T riassic (R haetian) strata, represented b y grey clayston es bearing c o a lified plant detritus, have b een found in on ly one borehole in the O borniki elev a tio n , south o f C zarnków.

T he L ow er Jurassic rocks are d ocum ented by 21 bore

h oles, m ostly in axial parts o f the N a k ło and P iła an ticlines (Fig. 4 ). T h ese are grey, fine-grained, coal silt-bearing sand

stones o f c la y e y cem ent. In p la ces, coarse-grained, p oorly lithified sandstones p assin g into sands and dark-brown, siderite-bearing m udstones, can a lso be found.

T he M id d le Jurassic subcrops on the sub-Tertiary sur

face are docum ented by 12 boreh oles, lo ca lised in a narrow belt on the lim bs o f the N a k ło and Piła an ticlin es (F ig. 4).

T h ese rocks represent grey m udstones and c la y sto n es w ith siderite, as w e ll as fo ssilifero u s sandstones.

T he U pper Jurassic rocks have been drilled by 23 b ore

h oles in a broad zon e on the S W lim b o f the N a k ło anticline and in the Skórka sy n clin e, as w e ll as in the axial part o f the Piła anticline and the Oborniki elevation . T h ese are usu ally

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y i ^ 3 — 5 ^ 6

F ig . 4 . Sub-T ertiary substratum in the M id d le N o te ć R iv er v a lle y region . 1 - con tour lin e s, 2 - g e o lo g ic a l boundaries: T - T r ia ssic . Ji - L o w e r Jurassic, J2 - M id d le Jurassic, J3 - U p p er Jurassic, K i - L o w e r C reta ceo u s, K 2 - U pper C retaceou s, 3 - a x es o f sy n c lin e s, 4 - a x e s o f a n tic lin e s , 5 - te c to n ic g rab en s, 6 - lo ca tio n o f b o reh o les and c r o s s-se c tio n lin es

grey, ch alk y, sandy or silty , fauna-bearing marls; rarely grey m u dstones, cla y sto n es, clays and lim eston es.

The L ow er C retaceous strata build the sub- Tertiary surface in the O borniki elevation (3 boreh oles) and in a narrow zo n e in the outer ba

sin b e lt T h ese are fo ssilifero u s, dark-grey marls and c la y e y m arls, accom p an ied b y dark, so m e  tim es sand-bearing, clays.

The U pper C retaceous strata have been docu m en ted by 20 b oreh oles in the southern part o f the area studied. T h ese are m o stly grey and dark-grey, sandy, p oorly lith ified marls that frequently com prise glau con ite. There also o c  cur dark-grey m udstones and m arly sandstones.

A cco rd in g to D a d lez (1 9 7 4 ), the present- day exten t o f M e so z o ic rocks is o f purely ero- sion al character due to syn -an d p ostdepositional u plift o f individual parts o f the P om eran ian - K u yavian S w ell.

T he base o f Tertiary strata sh o w s g o o d co n  cordance w ith g e o lo g ic a l structures described above (F ig. 4 ). This surface rises w ithin anticli

nes and low ers in sy n c lin e s (basins). The sub- Tertiary surface plu n ges tow ards the SE, sim i

larly as the Piła anticline a x is, and fo llo w in g the slo p e o f the a n ticlin e’s lim bs.

The h igh est part o f the Piła anticline is situ

ated at the continuation o f the W ielk op olsk a S w ell, uplifted in Jurassic tim es, and occurring SE o f the study area (D a d lez, 1974). This part o f

the P om eran ian -K u yavian S w e ll w as particularly liable to uplift co e v a l w ith and p ostd atin g the M e so zo ic sedim enta

tion. B etw een the Pila an ticline and a fragm ent o f the N a k ło anticline, the base o f the Tertiary form s a vast depression oriented N W -S E , c o in cid in g w ith the Skórka sy n clin e (Fig.

4 ). T his depression low ers tow ards the SE, from 90 m b.s.l.

c lo se to W yrzysk to < 2 0 0 m b.s.l. near G ołańcz. A lo n g the C h o d z ie ż -B o r u sz y n line, the sub-Tertiary surface is d is

sected by the C h o d zież d ep ression, w h o se base dips tow ards SW from 100 m b.s.l. to 3 2 2 m b.s.l. It is the B oruszyn area w here the C h o d zież d ep ression m erges w ith another depres

sion , oriented N W -S E , fo llo w in g the axis o f the C zarnków sy n clin e. T aking into accou n t the depth o f this structure (2 5 6 m b.s.l. near C zarnków ), high gradients and height o f its sid es, as w e ll as a certain co in cid en ce w ith the strike o f faults, it has been nam ed the C zarnków graben. Its bottom dips south-eastw ards.

SE o f C zarnków , K rygow sk i (1 9 5 2 , 1961a) described a low erin g in the sub-Tertiary surface (1 5 0 m b .s.l.), called the C iszk o w o depression. T his d epression appears to repre

sent a sh a llo w low erin g in the northern part o f the Oborniki elevation.

The S z a m o tu ły -O b o m ik i anticline sh o w s highly d iffer

entiated sub-Tertiary substratum (Fig. 4).

L ith ological differentiation o f rocks com prising the base o f Tertiary strata did n ot in flu en ce its m orphology, as sh ow n by the sam e elev a tio n o f the top o f different rock e x  posures. H igh r e lie f en ergy o f this surface, attainig 2 7 0 m, has been induced by tecton ic m ovem en ts (K rygow sk i,

1961b). T ecton ic control on m o rp h o lo g y o f the sub-Tertiary surface is particularly w e ll ev id en ced by the co in c id e n c e b e

tw een fault zo n es and b asem ent d ep ression s. The deep C h od zież depression originated in the C zarnków —T uchola fault zon e, alon g w h ich the surface o f the K uyavian S w ell low ers in respect to that o f the Pom eranian S w e ll (Stupnic- ka, 1989). M oreover, d epressions occurring in the N W part o f the study area appear to fo llo w fault zo n es that are per

pendicular to the S w e ll’s axis (F ig. 3). T he C zarnków gra

ben originated probably due to d ifferentiated u p lift o f indi

vidual b lock s o f the S z a m o tu ły -O b o m ik i and Piła an ticli

nes.

The area o f such a com p licated g e o lo g ic a l structure could bear ev id en ce o f differentiated tecto n ic m o v em en ts o f diversified am plitudes (D a d lez & M arek, 1974; D ad lez, 1980). It is generally accepted that the Piła, S z a m o tu ły - O bom iki and R o g o źn o an ticlines w ere b ein g u plifted during and after the M e so zo ic sedim entation, w h ereas sy n clin a l ar

eas, in clu d in g the C zarnków graben and C h o d zież depres

sion, w itn essed relative su b sid en ce.

DISTRIBUTION AND PROPERTIES OF TERTIARY STRATA

In the M iddle N o te ć R iver v a lle y Tertiary sed im en ts are ubiquitous, unconform ably o v erly in g M e so z o ic rocks (L istk ow sk a e t a l. , 1978; U n iejew sk a e t a l., 1979). Their distribution is docum ented by nearly 5 0 0 boreh oles, 80 o f

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62

J. DZIERŻEK

w h ich drilled Tertiary d ep osits d ow n to their base. The sm allest th ick n ess (15 m ) has been found in the N o te ć R iver v a lley N E o f C h od zież, th e largest (c a . 265 tn) - near Boru- szyn . The distribution o f Tertiary sedim ents reveals a cer

tain regularity. In areas w h ere the top o f M eso zo ic rocks is high, the th ick n ess o f Tertiary sed im en ts ranges from a few dozen to c a . 150 m, w h ereas depressions are filled by 2 0 0 m thick Tertiary strata (F ig. 5). The base o f Quaternary sed i

m ents clearly sh o w s that 50 m a.s.I. contour en circles vast, flat surfaces (elev a tio n s). T aking this le v e l as approxim ating the top o f Tertiary sed im en ts (G adom ska, 1957; K ow alska, 1960; K rygow sk i, 1961a), o n e should accept the C zarnków graben in fill b ein g 3 7 2 m thick. A n increase in thickness o f individual Tertiary stages (F ig s. 5 - 8 ) w ithin d epressions o f the sub-Tertiary surface (b asin s) and their decrease upon culm inations o f the S w e ll poin t to relative uplift o f the anti

clin es during the Tertiary sedim entation. T his idea is addi

tion ally supported by very sm all th ick n esses or the lack o f you n ger Tertiary stages upon uplifted regions (F igs. 7, 8).

T he stratigraphy o f Tertiary strata in the w estern part o f the P olish L ow land, in clu d in g the M iddle N o te ć R iver val

le y region, has been dealt w ith b y C iuk (1 9 7 0 ), D yjor &

Sad ow sk a (1 9 8 6 ), D yjor (1 9 9 2 ) and P iw ock i (1 9 9 1 ). N e w

C -D

MIASTECZKO KR

E WYRZYSK

j r 7 j i 'S

i c-D

" P r 2=pi:

r r y M

/J, n ,

Fig. 5. Distribution and thickness o f Tertiary and Quaternary sediments shown on selected cross-sections (cf. Fig. 2). Ji — Lower Jurassic, J2 - Middle Jurassic, Jj - Upper Jurassic, Ki - Lower Cretaceous, Ki - Upper Cretaceous, Pg - Paleogene, M - Mio

cene, PI - Pliocene, Q - Quaternary

investigations enable one to correct the p o sitio n o f so m e o f Tertiary lithostratigraphic m em bers in respect to the sch em es applied in b orehole descriptions. H o w ev er, the tra

ditional su b d ivision has to be kept, sin c e there is little p o ssi

b ility o f verification o f every sig le description, particularly as the M io ce n e /P lio cen e boundary is concerned.

T he Tertiary strata in question b elon g to three series:

O lig o cen e, M io ce n e and P lio cen e. S in ce on ly fe w boreholes drilled E ocen e and P a la eo cen e strata, th ey w ill be su b se

quently d iscu ssed together w ith m ore w id esp read O lig o cen e strata, and treated as P a leo g en e sedim ents.

The P a leo g en e sed im en ts (m o stly O lig o c e n e ) include sands, silts and clays, as w e ll as m u d ston es and sandstones containing phosphoritic con cretion s, sulphur, and plant d e

tritus. T h ese are m ostly shallow -m arin e sed im en ts (C iuk &

P ożaryska, 1982; P iw ock i & O lkow icz-P ap rock a, 1987).

The sm allest th ick n esses o f P a leo g en e sed im en ts (2 0 to 4 0 m ) have been encountered in the axial part o f the P iła anti

clin e (F igs. 4, 6), the h igh est o n es are con fin ed to sub-T erti

ary basem ent depressions, like 192 m c lo se to B oru szyn and 154 m near C zarnków (L istk ow sk a e t a l., 1978). D eviation s from this regularity are observed in the S z a m o tu ły -O b o m i- ki anticline, w here tecto n ica lly -in d u ced reduction in the thickness o f O lig o cen e sedim ents ( 0 - 6 m) is v isib le. P a leo  gen e sedim ents im m ed iately underlying Quaternary strata have been docum ented by 16 boreh oles, located upon large depressions w ithin the sub-Q uaternary surface, e.g . c lo s e to Piła and in the N o te ć R iver v a lle y (F ig. 5).

M io ce n e sedim ents have been drilled by m o st o f the b oreholes studied and are u su ally represented by fin e

grained, quartzose sands intercalated b y silty -c la y e y se d i

m ents, p assin g into thin layers o f c la y sto n es and m udstones.

Brow n coal m easures are represented by several metres thick layers (T rzcianka deposit). T he c y c lic ity o f sedim ents (sands - silts - cla y s - coal), as w e ll as the p resen ce o f plant detritus, irregular intercalations o f coal-b earin g cla y s, or h igh ly dispersed coal silt testify to p eriod ically changing sedim entary conditions w ithin lacustrine and - so m etim es - brackish-m arine basins (L istk ow sk a e t a l , 1978; C iuk &

Pożaryska, 1982; D yjor & Sad ow sk a, 1986; P iw o ck i, 1991).

M io ce n e sedim ents are u su ally grey-brow n due to the pres

en ce o f coal silt, w hereas quartzose sands are, as a rule, light-grey. The thick n ess o f M io ce n e sed im en ts changes from 0 to 183 m (F ig. 7), ranging b etw een 4 0 and 80 m in the P om eran ian -K u yavian S w e ll. O n ly tecto n ica lly -co n - trolled depressions w ithin the S w ell do reveal a m arked in

crease in the thick n ess o f M io c e n e strata. T he S z c z e c in - M o giln o Trough bears M io ce n e sed im en ts 100 m thick, in

dicating a ten d en cy to tecton ic su b sid en ce o f this trough in respect to the P om eran ian -K u yavian S w e ll (K ow alsk a, 1960). T he r e lie f o f the top o f M io ce n e sed im en ts is co n sid  erably less differentiated as com pared to the old er surfaces.

A transition from M io ce n e to P lio cen e sedim entation w ithin the sam e terrestrial, gradually shrinking basin, w as continuous (U n iejew sk a e t a l ., 1979; C iuk & Pożaryska, 1982; P iw ock i, 1991; D yjor, 1992). T h e P lio c e n e strata are represented b y clays, silts w ith fine-grained sands, and vari

egated clays. The low er parts o f so m e logs o f P lio cen e se d i

m ents do a lso contain thin interlayers o f brow n co a l or co a lified plant detritus. P lio cen e sed im en ts do not occur

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63

Fig. 6. T h ic k n e ss o f P a le o g e n e strata (d a sh ed line m arks the a x is o f th e P ila a n tic lin e)

Fig. 7. T h ic k n e ss o f M io c e n e strata (d a sh ed line m arks the a x is o f th e P ila a n tic lin e)

throughout m o st o f the Pom eranian S w ell (P iła anticline) and the N o te ć R iver v a lley ; in other areas their thickness ranges from a few to 3 0 m and, on so m e anticline lim bs, ev en to 6 7 m (F ig. 8). Such a pattern results prim arily from g la cio tecto n ic p rocesses (C iuk, 1955; K ow alska, 1960; K ry

g o w sk i, 1952, 1961a, b, 1962; D yjor, 1992).

MORPHOLOGY AND ORIGIN OF SUB-QUATERNARY BASEMENT

T he principal topographic elem en ts o f the sub-Q uater- nary surface are represented b y elev a tio n s and intervening large and d eep depressions. T h ese are, from the north to the south, the Skrzatusz, G łu p czyn , B ia ło śliw ie , Trzcianka, Szam ocin , Jędrzejew o, P odanin, G ołań cz and L udom y e le  vations (F ig. 9), w h o se h eig h t ranges from 4 0 to 60 m a.s.l., approxim ating the top o f Tertiary sedim ents (K ow alska,

Fig. 8. T h ic k n e ss o f P lio c e n e strata (d a sh ed line m arks the a x is o f t h e P ila a n ticlin e)

1960; M aksiak & M róz, 1978; G o g o łek , 1992). L ocally, the elevation s are overtopped by m inor cu lm in ation s, like those upon the T rzcianka (9 0 m a.s.l.) or G o ła ń cz and Jędrzejew o elevation s (8 0 m a.s.l.; cf. F ig. 9). T he G ołań cz, Szam ocin , B ia ło śliw ie and G łu p czyn e lev a tio n s are probably a co n  tinuation o f the so -ca lled G n iezn o -T u rek S w e ll, w hereas the Jędrzejew o and L udom y elev a tio n s represent a continu

ation o f the Poznań Sw ell; all o f th em distin gu ish ed b y K ry

g o w sk i (19 6 1 b ). In the northern part o f the study area the elevation s are com p osed m o stly o f M io ce n e strata, those in the southern part b ein g built up from P lio c e n e sedim ents (F igs. 7 -9 ) .

T he elev a tio n s are accom p an ied by deep d ep ression s o f variable orientation (F ig. 9). T he m o st e x ten siv e o n e is the N o te ć depression, fo llo w in g the N o te ć R iver v a lle y . Its b ot

tom attains 84 m b.s.l. N E o f C h o d zież, rising to the east and w e st up to 2 0 m b.s.l. The N o te ć d epression is 1 to 8 km w id e, its sid es b ein g steep and high, up to 115 m SE o f C h o

dzież. In the m iddle reach o f the N o te ć R iver v a lley , the so- called N o te ć furrow has been found, representing a low erin g o f the sub-Quaternary surface, en circled by the 0 m a.s.l.

contour (K ow alsk a, 1960; K ry g o w sk i, 1961a). G eo lo g ica l map 1 :2 0 0 ,0 0 0 w ith ou t Quaternary d ep osits (L istk ow sk a e t a l., 1977; U n iejew sk a & N o se k , 19 7 8 ) sh o w s deeper struc

tures o f slig h tly different shape.

T he N o te ć depression m erges on the north w ith the G w da depression, w h o se orientation fo llo w s in part the pre

sent-day course o f the N o te ć R iver v a lle y (F ig. 9). A nother w ell-d o cu m en ted depression, representing a continuation o f the G w da depression, occurs north o f the study area (M ak

siak & M róz, 1978). In the d eep est part, south o f Piła, the sub-Q uatem ary surface p lu n ges to 4 0 m b.s.l. T he bottom o f the G w da d epression is u neven and tilted to the south. T his depresion is jo in ed near Piła b y the R óża W ielk a depression on the w est, separating the Skrzatusz and T rzcianka e le v a  tions, and b y the Skórka d ep ression on the east, separating the G łupczyn and B ia ło śliw ie elev a tio n s. T he bottom s o f these subparallel d epressions occu r at 10 m a.s.l. to 30 m b.s.l.

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64

J. DZIERŻEK.

Fig. 9. S ub-Q uaternary su rfa ce in the M id d le N o te ć R iv er v a lle y region . I - co n to u r lin e s, 2 - c liffs , 3 - lo c a tio n o f b o reh o les and g e o lo g ic a l cr o ss-se c tio n s;

e - e le v a tio n , d - d ep ressio n

In the southern part o f th e study area, b etw een S za m o  cin (N E ) and B oru szyn (S W ), another im portant depression o f the sub-Quaternary surface occurs, being called B oruszyn depression (F ig. 9). In the N E part its bottom is narrow and relatively sh a llo w , en circled b y 0 m a.s.l. contour, w hereas to the S W its siz e increases rapidly. C lo se to B oruszyn, the top o f the Tertiary (O lig o c e n e ) sed im en ts occurs at 1 4 7 -1 1 0 m b .s.l., w h ich g iv e s 1 5 0 -1 8 0 m h eight differen ce in respect to the surrounding elev a tio n s. T he depression is here 5 km w id e (B araniecka e t a l., 1986). A southern continuation o f the B o ru szy n depression is marked by a buried v a lley that fo llo w s the Tertiary S zam otu ły graben, described by G ogo- łek (1 9 9 1 a , b).

T h e B oru szyn dep ression is jo in ed by p oorly d ev elo p ed K am ionka depression, oriented N W -S E . Its N W continu

ation co u ld b e represented b y several narrow v a lle y s that d issect the Trzcianka elev a tio n (F ig. 9).

Apart from m utually m erging, longitudinal depressions, the sub-Q uaternary surface reveals as w ell a num ber o f sem i-circular depressions w ithout outlet, like that in the d eep est part o f the N o te ć depression near C h od zież (< 8 0 m b.s.l.). O ther landform s o f this type occur w ithin the Trzcianka (b e lo w sea le v e l), Jędrzejew o (2 0 m a.s.l.) and G o ła ń cz (b e lo w sea le v e l) elevation s. T hese landform s are accom p an ied b y e llip so id a l highs that represent the pre

v io u s ly m entioned cu lm in ation s (F ig. 9).

T he recent studies d o n ot confirm the presence o f a sub- Quaternary v a lle y w h ich , according to K ow alsk a (1 9 6 0 ), w o u ld represent jo in ed m eridional segm ents o f the present- day W arta and G w da R iver v a lley s. A dubious trace o f such a jo in t cou ld be found w ithin a depression near R ogoźno.

T he a b o v e rev iew con firm s the p resence o f the hitherto

d escribed r e lie f elem en ts, slig h tly m o d ify in g their outline and extent. T he sub-Q uatem ary surface (F ig. 9) represents a picture gen erally sim ilar to that sh o w n o n the 1:2 0 0 ,0 0 0 g e o lo g i

cal m ap stripped o f Quaternary sedim ents (L istk ow sk a e t a l., 1977; U n iejew sk a & N o se k , 1978). T he m o st im portant ch an ges, in respect to previous studies, are as fo llo w s:

(1 ) the outline o f the N o te ć d ep ression ap

p roaches that o f the recent river v a lle y , particu

larly in its southern segm ent;

(2 ) the B oru szyn dep ression is aligned N E -S W ;

(3 ) the R óża W ielk a d ep ression has another character, as com pared to that describ ed by K o  w alsk a (1 9 6 0 ), w h o interpreted it as a jo in t o f the N o te ć furrow and O b ra -P ło n ia depression;

and

(4 ) the detailed id en tification and n o m en  clature o f the sub-Q uatem ary elev a tio n s and d e

pressions are introduced for the first tim e.

T he sub-Q uatem ary surface in the M iddle N o te ć R iver v a lley region has a p o lig en etic character due to: g lacial erosion and g la cio tec- tonic p rocesses, flu vial erosion, and the struc

ture o f so lid basem en t (K ry g o w sk i, 1952, 1961b, 1962, 1975; C iuk, 1955; K ow alska, 1960; Baraniecka, 1975, 1980; M aksiak &

M róz, 1978; L istkow ska e t a l., 1978; U n iejew sk a e t a l., 1979; G ogołek , 1991a, b). R elief-fo rm in g p ro cesses, re

corded in the shape o f the sub-Q uaternary surface, have been repeating throughout the Quaternary; therefore, the m orphogenetic co m p lex ity o f the surface in question affects not on ly the character o f individual p ro cesses, but also their age.

G lacial erosion had d e c is iv e in flu en ce upon the final shape o f the sub-Q uatem ary surface. Individual ice-sh eets rem oved m aterial from so m e elev a tio n s, w h o se surfaces w ere additionally denuded during interglacial stages. L ocal culm inations overtopping flat e lev a tio n crests (cf. Jędrzeje

w o , southern G ołań cz, and SW T rzcianka ele v a tio n s) o rig i

nated due to pushing up b asem en t m aterial b y advancing ice-sh eet. Such a process w a s b ein g repeated during sub

sequent glacial stages, as ev id en ced by the fact that flat e le  vation crests are com p osed o f M io ce n e sed im en ts (Skrza- tusz, G łupczyn, N E T rzcianka e lev a tio n s), w h ereas the cu l

m inations com prise m o stly P lio c e n e c la y s o f large th ick  n esses (F igs. 8, 9). G lacial erosion resulted as w e ll in shap

ing o f num erous depressions in the sub-Q uatem ary surface, due to the activity o f both large glacial lob es (B oru szyn , G w da, K am ionka, R óża W ielk a d ep ression s) and sm all g la  cial ton gu es (B ia ło śliw ie , T rzcianka, Jędrzejew o e le v a  tions). Sim ilar processes h ave frequently been described from other areas (K rygow sk i, 1952, 1961a, b, 1975; Ciuk, 1955; Lam parski, 1972, 1983, 1991; M aksiak & M róz, 1978; B araniecka, 1980; K asprzak, 1988; K ozarski &

K asprzak, 1992).

A nother im portant relief-form in g p ro cess that shaped the sub-Q uatem ary surface in the study area w a s flu v ia l ero

sion that produced or m od ified the p re-existin g, elon gated

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65

d ep ression s (N o teć, N E B oru szyn , northern G w da and other d ep ression s). Erosion co n fin ed to individual interglacials af

fected the pre-existin g g la cio tecto n ic depressions.

T he in flu en ce o f g e o lo g ic a l structure and m orphology o f the base o f Tertiary sed im en ts upon p rocesses shaping the sub-Q uatem ary surface c lo s e to the contact o f large M e so  z o ic structures (P om eran ian -K u yavian S w ell, S z c z e c in - M o giln o T rough) has already been described by L ew iń sk i &

S a m so n o w icz (1 9 1 8 ), L e n c e w ic z (1 9 2 6 ), Galon (1 961a, b), R oszk o (1 9 6 8 ), K opczyńska-Ż andarska (1 9 7 0 ), B araniecka (1 9 7 5 , 1980) and N iew ia ro w sk i (1 9 8 3 ). I w o u ld on ly lik e to focu s on m utual relationships b etw een m orphological e le  m ents o f the sub-Q uatem ary surface and en d ogen ic proc

esses. S ystem atic exaration o f th ose elevation s w hich d e v e l

oped upon anticlines o f the P om eran ian -K u yavian S w ell led to rem oval o f P lio c e n e and L ow er Quaternary sedim ents and cou ld indicate a persisting ten d en cy to tectonic uplift.

Principal linear elem en ts o f the sub-Q uatem ary surface are roughly co in cid en t w ith landform s and structures o f the sub- Tertiary basem ent. In both ca ses N E —SW and N W —SE trends d om inate. The B oru szyn and K am ionka depressions, as w e ll as a part o f the N o te ć depression are located exactly upon troughs w ithin the sub-Tertiary surface (F igs. 4 , 9).

C on sid erin g the fact that glacial and flu vial erosion pro

ceed ed alo n g the sam e linear zon es throughout different Quaternary stages, one can con clu d e about fault activity in this area (F ig. 3).

STRATIGRAPHY AND LITHOLOGY OF QUATERNARY SEDIMENTS

Oldest (Narcvian) Glaciation

T he o ld est Quaternary sedim ents in the study area are probably represented by tw o till beds, separated by a thin silt layer, found in the B oru szyn depression (F igs. 10, 11).

The low er, grey-green and sandy till, containing clasts and intercalations o f brown c la y s and brow n coal, has been found by tw o b oreholes. In both ca ses the till is underlain by dark-brown, silty P a leo g en e sedim ents. T he base o f the till lies at 147 and 125 m b .s.l., its thickness attaining 6 m . T he upper till, also found in tw o boreholes, is dark-grey, sandy, and contains cob b les and interlayers o f silts and coal-bear

ing clays. Its base is situated 115 m b .s.l., and its thickness ranges from 3.5 to 5 m .

U p to n o w , the tills occurring in a deep glaciotecton ic depression c lo s e to B oru szyn have been associated w ith the till found at R y c z y w ó ł, d espite height differen ces up to 80 m, and treated as the older le v e l o f the S outh-P olish G lacia

tions (L istk o w sk a e t a l. , 1978; Baraniecka e t a l., 1986).

Sim ilarly, tills occurring w ithin deep exaration depressions (3 0 0 m b .s.l.) in eastern G erm any (Ć epek, 1967) used to be linked w ith the Elsterian I glacial stage. On the other hand, the seq u en ce described from the M id d le N o teć R iver v a lley correlates w e ll w ith tw o till beds separated by flu vioglacial series, d istinguished in the M y ślib ó rz Lake D istrict by K o z  ło w sk a (1 9 7 4 , 1979), and ascribed to the old est glaciation.

K opczyńska-L am parska (1 9 7 9 ) also postulates the presence o f the o ld est glaciation near S zczecin . In turn, tw o tills (8

and 5 m thick) found in the W estern P om erania, o f bases situated 130 and 110 m b .s.l., resp ectiv ely , and considered as slid es o f the South P olish tills w ithin v a lle y s shaped dur

ing the Great Interglacial (K opczyńska-Ż andarska, 1970), cou ld have been reinterpreted as b ein g eq u ivalen t to the old  est glacial stage. Bipartition o f tills o f the o ld est (N arevian) G laciation has been described from other regions o f P oland (R ó ży ck i, 1967; Straszew ska, 1968; Lam parski, 1983). O ne can suppose, therefore, that the lo w est-situ a ted glacial sed i

m ents in the study area originated during the N arevian G la

ciation. Their assignm ent to the S ou th -P olish G laciation (L istk ow sk a e t a l., 1978; B araniecka e t a l., 1986) d oes not explain rem arkable height d ifferen ces o f the till base in a relatively sm all area: from 147 m b.s.l. at B oru szyn to 13 m b.s.l. at Piła.

It appears that the d evelop m en t o f the o ld est glaciation w as largely in flu en ced by m o rp h o lo g y o f the so lid b ase

m ent, despite the thick co v er o f o v erly in g Tertiary se d i

m ents (F igs. 4 , 6 - 8 ) . T he exten t o f this g laciation in W estern P oland approaches that o f the S z c z e c in T rough in the b ase

m ent. Its central, m o st rapidly su b sid in g part com p rises s e v  eral tens o f m etres thick tills o f the old est glaciation (K o z  ło w sk a , 1974, 1979; K opczyńska-L am parska, 1979). The marginal part o f the S zczecin T rough, c lo s e to the Szam o- tu ły-O b orn ik i anticline in S W part o f the study area, reveals the oldest glacial tills o f m uch m ore sm aller th ick n esses and form ing tw o beds. W e are confron ted here, perhaps, w ith the m axim um extent o f the o ld est (N arevian ) G laciation.

T he P om eran ian -K u yavian S w e ll probably b lock ed further, north-eastw ard advance o f this glaciation.

O ne should take n otice o f the im portance o f such a lo- bate transgression o f the first glaciation in shaping the base o f Quaternary sedim ents. In the B oru szyn d ep ression, gla

ciotecton ic activity o f a glacial lob e during the N arevian ad

v an ce w as probably in ten sified b y tecto n ic a ctivity o f this region, the traces o f w h ich can a lso be found in the Early P leisto cen e (cf. Baraniecka e t a i , 1986).

Podlasian Interglacial

T his interglacial is represented by g r e y -y e llo w ish , fin e

grained sands w ith adm ixtures o f coarse-grained sands and singular gravels that o v erlie the low er or upper tills o f the old est glaciation (F igs. 10, 11). T heir th ick n ess, determ ined b y boreholes near B oruszyn, attains 4 0 m . U n ev en base o f these sedim ents and the lack in on e b oreh ole o f the upper N arevian till testify to intensive erosion p reced in g d ep o si

tion o f this series. Petrographie co m p o sitio n o f th ese d ep o s

its in cludes, apart from quartz and feldspars, granitoids and sandstones, probably derived from eroded p re-existin g gla

cial sedim ents. L istkow ska e t al. (1 9 7 8 ) con sid er this series as flu vioglacial sedim ents o f the S ou th -P olish G laciation.

Nidanian Glaciation

G lacial d ep osits, docu m en ted by 4 b oreh oles near B oru

szy n (F igs. 10, 11) and in the N o te ć R iv er v a lle y c lo s e to Zacharzyn (F ig. 12), o verlie sands and gravels. N ear B oru

szyn , glacial sed im en ts o f that age are represented by grey- blue or grey till, com prising clasts o f crystallin e rocks, sand-

9 — Annales...

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66

J. DZIERŻEK

H

B o ru s z y n R y c z y w ó t W ą g ro w ie c

5 km

: 1 - - - 5 \v v -d 8

t a

¹⁰ ^{r - 11}

F ig . 10. G e o lo g ic a l c r o s s -s e c tio n G - H (cf. Fig. 2 ). I - g r a v els and p eb b les, 2 - vari-grained sa n d s w ith g r a v e ls, 3- m ed iu m -g ra in ed sands, 4- fin e -g r a in e d sa n d s, 5- silts, 6- c la y s, 7 - tills, 8- lacu strin e m arls, 9- peat, 10-- fa u lts in ferred , 11- g la c io te c to n ic d efo rm a tio n s; Ji - L o w e r Ju rassic, J2 - M id d le Jurassic, J3 - U p p er Jurassic, K i - L o w e r C reta ceo u s, K 2 - U p p er C reta ceo u s, P g - P a le o g e n e , M - M io c e n e , PI - P lio c e n e ; Q uaternary: N a - N a r e v i a n G la cia tio n , po - P o d la sia n In terglacial, N i - N i d a n i a n G la c ia tio n , ml - M a lo p o la n ia n In terglacial, S I - Sanian I G la cia tio n , f - F erd yn and ovian In terglacial, S II - S an ian II G la c ia tio n , m a - M a zo v ia n In terglacial, O - O dranian G la cia tio n , 1 - L ub avian In terglacial, W - W artanian G la cia tio n , e - E e m ia n In terg la cia l, V - V istu lia n G la cia tio n : V | - V 5 - sta d ia ls (p h a se s), V 1/2 - V 3/4 - interstadials (in terp h a ses), H - H o lo c e n e

ston es and brow n coal. T he base o f the till lies at 92 to 70 m b .s.l., its m axim u m th ick n ess attaining 12 m . In the Zacha- rzyn area (F ig. 12), the N id an ian glacial deposits include gravels and co b b les cem en ted by clays and intercalated by fine-grained sands, o f total thickness o f ca.8 m. The top o f the underlying P a leo g en e m u d ston es occurs at 85 m b.s.l.

The recession o f this glaciation left several m etres thick layer o f flu v io g la cia l sands and gravels that overlie the gla

cial till near B oruszyn (F ig s. 10, 11).

M alopolanian Interglacial

T his interglacial series is represented by sand-gravelly sed im en ts, 4 0 m thick, o v erly in g the N idanian or Podlasian strata, and docum ented near B oruszyn and Zacharzyn (Figs.

1 0 -1 2 ). The base o f this series is situated at 90 to 60 m b.s.l.

Large th ick n ess o f this series, w ell-p reserved grading and the m o d e o f occurrence, all indicate its fluvial origin. Ero- sional d issectio n o f the sub-Q uatem ary basem ent c lo s e to P ila (F ig. 11), filled w ith sands and gravels, could also rep

resent the M alopolanian Interglacial stage. A lternatively, o n e can relate its origin to subglacial tunnel v a lley accum u

lation during the Sanian I stage.

R eactivation o f tecton ic zo n es, induced by relaxation o f individual basem ent b lock s due to the recession o f the N i

danian ice-sh eet, favoured the d evelop m en t o f river v a lley s in the M alopolanian Interglacial. The ou tflo w w as, at least partially, directed tow ard the south-w est.

T he identification and dating o f South-Polish G lacial

sedim ents in this region raises so m e d ifficu lties due to the variable num ber o f glacial beds d istin gu ish ed and the lack o f unequivocal k ey horizons. In W estern P oland, one (K ry

g o w sk i, 1961b, 1975; M aksiak & M róz, 1978; G ogolek , 1991b; Jeziorski, 1 9 9 1 a -c ), tw o (K opczyńska-Ż andarska, 1970; L istk ow sk a et a l , 1978; K o zło w sk a , 1979; U n ie je w  ska et al,. 1979; D ąbrow ski, 198 5 ) or ev en three (K ry g o w  ski, 1952; K opczyńska-L am parska, 1979; G o g o łek , 1991a) South-Polish till beds have b een d istin gu ish ed . In Eastern Germ any, the so -ca lled C rom erian-E lsterian co m p lex has been identified, in cluding both co ld (stadials, g la cia ls) and w arm (interstadials, interglacial) stages o f different rank (Ć epek, 1967, 1986; Lindner, 1988).

A s far as the M iddle N o te ć R iver v a lle y region is co n  cerned, it appears that the Sanian II till is eq u ivalen t to the upperm ost till from am ong S ou th -P olish till beds hitherto- described, as w e ll as to the low er part o f the M id d le-P olish till co m p lex . The Sanian I till bed o f previou s stratigraphie sch em es cou ld be associated w ith the m iddle or upper South-Polish till, the N idanian till b ein g eq u iv a len t to the lo w est or low er till from am on g this co m p lex . T he Sanian II till in the M id d le N o te ć R iver v a lle y region co u ld a lso be correlated w ith the upper part o f the Elsterian (E lsterian II) co m p lex , w hereas the Sanian I till cou ld be an eq u ivalen t o f the Elsterian I, and the N id an ian till co u ld be related to the Stadial B o f the Crom erian co m p lex , d istin gu ish ed in G er

m any (Ć epek, 1967, 1986; W iegank, 1982; Lindner, 1988, 1991b).

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QUATERNARY SEDIMENTS fN THE NOTEĆ RIVER VALLEY

67 M N

Piła Ujście B oruszyn

Sanian I Glaciation

T his glacial stage is represented by a glacial till bed (the third one in the B oru szyn area), w h o se base is situated at 60 to 2 0 m b.s.l. (cf. Ć epek, 1967; L istkow ska e t a l ., 1978;

U n iejew sk a e t a l., 1979). It is dark-grey, som etim es green

ish (brow n near T rzcianka), sandy till bearing gravels and c o b b les, intercalated in p la ces by blue clays. Its thickness ranges from a few to 25 m , averaging at a d ozen or so m etres (F igs. 10, 11, 13, 14).

C lo se to C h od zież, the rem nants o f this till are repre

sented b y a thin layer o f lag, fillin g a depression in the sub- Q uatem ary basem ent (F ig. 13), w hereas near Piła the Sanian I till fills the flat-bottom G w da d epression (Fig. 14). T he re

ce ssio n o f the Sanian I G laciation left a few m etres thick sands preserved near P iła (F ig. 14).

Strong glacial erosion during this stage m od ified the p re-existin g g la cio tecto n ic and erosional depressions near C h o d zież (F ig. 13) and P iła (F ig. 14). G laciotecton ic depres

sion s filled by tills d ep osited during the Sanian I glaciation occur S and N E o f P iła (F ig. 11) and c lo s e to R unow o (Fig.

14).

Fcrdynandovian Interglacial

T his stage is represented b y clastic sedim ents overlyin g the Sanian I till or Tertiary bedrock w h ich , in turn, are c o v  ered by another till bed. N ear B oru szyn , th ese sedim ents are co m p o sed o f dark-grey, vari-grained sands w ith gravels in the bottom part and o f g r e y -y e llo w , very fine-grained sands and silts in the upper part (F ig. 10). O ne can suppose, there

fore, that th ey represent flu vial sedim ents. The total thick

n ess o f this series attains 4 0 m; its base b ein g situated at 6 0 - 5 0 m b .s.l. near Skórka (Fig. 15), the Ferdynandovian Interglacial sedim ents are co m p o sed o f coarse-grained sands and fine gravels, 23 m thick, w h o se bottom occurs at

30 m b.s.l. N ear C h o d zież (F ig. 13), in turn, th is stage is rep

resented b y 30 m thick sands and gravels, drilled by tw o boreholes d ow n to 60 m b.s.l. T h ese sed im en ts overlie w ash ed -ou t sedim ents o f the Sanian I G laciation. A ccord in g to L istkow ska e t al. (1 9 7 8 ), th ese d ep osits are a fragm ent o f the m uch m ore thicker (105 m ) in fill o f a su b glacial channel, form ed during the M id d le-P o lish G laciation. Sim ilarly d e

v elo p ed interglacial sed im en ts have been fou n d at Z acha- r z y n (F ig . 12).

East o f R y c z y w ó ł (F ig. 10), 25 m thick fine-grained, probably lacustrine sands occur in the p osition o f the Ferdy

nandovian Interglacial sedim ents. A n a lo g o u s origin and age can be ascribed to fine-grained sands overlain b y cla y s, that fill a sub-Q uatem ary d ep ression near Piła (F ig. 11; cf.

D ąbrow ski e t a l., 1987).

Sedim entary record o f the F erdynandovian Interglacial is not su fficien t enough to reconstruct drainage pattem dur

ing this stage. O ne can o n ly infer that river v a lle y s in that tim e utilised p re-existin g d ep ression s and rem oved , to a large extent, p reviou sly d ep osited Sanian I sed im en ts (B oru

szyn depression; Figs. 10, 11), d issectin g as w e ll the sub- Q uatem ary bedrock (Skórka depression; Figs. 9, 15). A riv

er in the Skórka depression flo w e d w estw ard s, w h ereas v a l

ley s in the southern part o f the study area fo llo w e d the B oru

szyn depression, characterised b y the so u th -w esterly out

flo w .

Sanian II Glaciation

The Sanian II (W ilg a accord in g to M ojski, 1982 and Baraniecka, 1990) G laciation is represented b y a till d ocu  m ented b y a dozen or so b oreholes; the fourth till bed in the B oruszyn area. It is a com pact, grey or dark-grey till bearing cob b les and clasts o f x y lites or lign ites. F ew b oreholes drilled o n ly its traces, i.e. lag or isolated S can d in avian -d e

rived clasts. T he till is su b d ivid ed in p la ces b y a thin sand