Geo log i cal Quar terly, 2017, 61 (2): – DOI: http://dx.doi.org/10.7306/gq.1346
The im pact of postglacial palaeoenvironmental changes on the prop er ties
of sed i ments in the ket tle hole at Jurki (NE Po land)
Tomasz M. KARASIEWICZ
1,*, Piotr HULISZ
1, Agnieszka M. NORYŒKIEWICZ
2,
Renata STACHOWICZ-RYBKA
3, Adam MICHALSKI
1, Micha³ D¥BROWSKI
1and Wojciech W. GAMRAT
11 Nicolaus Co per ni cus Uni ver sity, Fac ulty of Earth Sci ences, Lwowska 1, 87-100 Toruñ, Po land
2 Nicolaus Co per ni cus Uni ver sity, In sti tute of Ar chae ol ogy, Fac ulty of His tory, Szosa Bydgoska 44/48, 87-100 Toruñ,
Po land,
3 Pol ish Acad emy of Sci ences, W³adys³aw Szafer In sti tute of Bot any, Lubicz 46, 31-512 Kraków, Po land
Karasiewicz, M.T., Hulisz, P., Noryœkiewicz, A.M., Stachowicz-Rybka, R., Michalski, A., D¹browski, M., Gamrat, W.W., 2017. The im pact of postglacial palaeoenvironmental changes on the prop er ties of sed i ments in the ket tle hole at the site of Jurki (NE Po land). Geo log i cal Quar terly, 61 (2): 000–000, doi: 10.7306/gq.1346
This re search is fo cused on a small ket tle hole lo cated within the Mor¹g mo raines (I³awa Lake Dis trict, NE Po land). The study ob jec tive was to de ter mine the im pact of palaeoenvironmental changes on prop er ties of sed i ments fill ing the bot tom of the ket tle hole. Sedimentological, geo chem i cal, and palaeobotanical stud ies en abled us to dis tin guish sev eral de vel op ment phases of the ket tle hole, and clus ter anal y sis per formed on physicochemical data yielded seven lo cal geo chem i cal zones (JuI/I to JuI/VII). The be gin ning of biogenic sed i men ta tion in the con di tions of a small wa ter body, func tion ing in the Late Gla cial pe riod (4.20–4.10 m), was de ter mined on the ba sis of palaeobotanical re search. Sed i ments de pos ited in the lake dur ing its fur ther evo lu tion were rich in microelements such as Ca, Na, Mg, and K, and to a smaller ex tent – Fe and Mn (JuI/I–III lo cal geo chem i cal zones). The Late Gla cial lac us trine pe riod ended with the ac cu mu la tion of very silty, pol len-free gyttja, with a strati graphic hi a tus (JuI/IV, 3.40–3.20 m). The sed i ments were en riched with SiO2ter, which in di cates an in creased rate of slope ero sion, and con cre tions of Fe-Mn oc cur ring be low this layer (JuIII) pro vide ev i dence for low er ing of the wa ter level and even des ic ca tion. In the Ho lo cene, the lac us trine pe riod ended with the ac cu mu la tion of coarse de tri tal gyttja (3.20–2.60 m). Palaeobotanical data in di cate that the next group of sed i ments were de pos ited in the Late Subboreal and Subatlantic pe ri ods (2.60–0.0 cm, JuI/V–VII; sedge peat). Their prop er ties were var ied and re lated to hydrologic con di tions, lim ited de nu da tion, and veg e ta tion suc ces sion. There was also a sig nif i cant change in the trophic con di tions of the wa ter and con se quently in the sed i ments of the ket tle hole, which changed dur ing the lac us trine pe riod from ba sic to acid, and strongly acid in the sur -face layer. This re ac tion may be re lated to a change in the wa ter re gime as well as to hu man im pact in the en vi ron ment, which led to the col o ni za tion of the peat bog by Sphag num moss.
Key words: young gla cial land scape, ket tle hole, end mo raines, geo chem i cal anal y sis, biogenic de pos its.
INTRODUCTION
Ket tle holes are a com mon fea ture of a young gla cial land -scape. They are de fined as small, shal low, depressional wetlands of gla cial or i gin with wa ter sup ply com ing from closed catch ments (Kalettka and Rudat, 2006). As iso lated de pres sions with ver ti cal wa ter fluc tu a tion, they are usu ally very sen si -tive to both nat u ral and anthropogenic en vi ron men tal changes (e.g., Küster et al., 2011). There fore, anal y sis of sed i ments de pos ited at their bot toms is of ten a key el e ment in the re con struc tion of e.g., palaeoclimatic, palaeohydrological, palaeo -botanical and sometimes archaeological conditions.
The func tion ing of these land forms may be strongly linked to re gional or lo cal set tings and there fore largescale changes as -so ci ated with cli mate and hy dro log i cal con di tions may af fect their eco log i cal in teg rity (Drexler et al., 1999; Fra ser et al., 2001). The most im por tant ef fects of such changes may in clude changes in the de po si tion/sedentation of sed i ments, fluc tu a tions in wa ter lev els and in creased peat de com po si tion (Gor -ham and Rochefort, 2003; Lamentowicz et al., 2008; Kara -siewicz et al., 2014b; Forysiak, 2015).
Ket tle holes are typ i cally lo cated in ag ri cul tural ar eas (Kochanowska et al., 1998; Karasiewicz et al., 2014a; Kleeberg et al., 2015). Ac cord ing to Kalletka and Rudat (2006), there are two main hydrogeomorphic types of these forms: fen type (with grow ing fen) and open-wa ter type (per ma nently or tem po rarily flooded, filled with peat and non-peat sediments).
Many au thors (e.g., Frielinghaus and Vahrson, 1998; Podlasiñski, 2013; Œwitoniak, 2014; Karasiewicz et al., 2014b) stress that, due to long-term ag ri cul tural use, the catch ment area is prone to ac cel er ated soil ero sion by run off. Con se -quently, ket tle holes may re ceive abun dant terrigenous ma te rial
* Corresponding author, e-mail: mtkar@umk.pl
Received: March 11, 2016; accepted: July 13, 2016; first published online: March 2, 2017
from ad ja cent slopes, which may lead to their dis ap pear ance and lev el ling of the land re lief. Their sed i ments can act as sinks for nu tri ents (N, P and K), pes ti cides, and heavy met als, and con se quently as a geo chem i cal bar rier which re duces the spread of pol lut ants (Coo per and Knight, 1990; Bilotta et al., 2007; Podlasiñska, 2012).
Ket tle holes in Po land are still rel a tively rarely in cluded in palaeoenvironmental stud ies. This is due to the wide spread be lief that their sed i ments re flect only lo cal changes in the en vi -ron ment, and hence the ob tained re sults might be of lim ited use. The ex am ples pre sented be low, how ever, prove the con trary. Com pre hen sive palaeogeographic stud ies in volv ing geo chem i cal anal y ses were con ducted by Borówka (1992) on sed i -ments col lected from small ket tle holes in West ern Pomerania. Sim i lar stud ies car ried out by Ma jor (2009) con cern the func -tion ing of ket tle holes in the drain age ba sin of the up per Parsêta River. Szwarczewski (2008) and Szwarczewski and Kupryja -nowicz (2008) de scribed the de vel op ment stages of ket tle holes in the East ern Suwa³ki Lake Dis trict near the town of Sejny based on the prop er ties of their sed i ments. In ter dis ci plin -ary stud ies of sed i ments of sin gle land forms were con ducted in the Brodnica Lake Dis trict (Karasiewicz et al., 2012, 2014b; Mendyk et al., 2015), and in the neigh bour hood of £ódŸ (Lamen to wicz et al., 2009; Twardy et al., 2010). There are also ex am ples of re search on geomorphological pro cesses con -nected with en vi ron men tal changes dur ing the Late Pleis to cene and the Ho lo cene in the moun tain ar eas (e.g., Jäger et al., 2015; Malkiewicz et al., 2016). A com mon ob jec tive of these stud ies was to re con struct the palaeoenvironmental con di tions re corded in sed i ments, which were treated as ar chives and car ri ers of in for ma tion. The au thors ob tained good cor re la tions be tween lo cal and re gional palaeogeographic changes. An ex am ple of a dif fer ent ap proach was stud ies in the field of palaeo ec ol ogy that ana lyse the manin duced trans for ma tions of the en -vi ron ment in the Tuchola For est (Lamentowicz et al., 2007, 2008). The re search on ket tle holes may also be help ful in de -ter min ing the chronostratigraphy of geomorphological events in river val leys. The re sults ob tained by Krzeœlak et al. (2014) link the be gin ning of lac us trine sed i men ta tion in the kettle hole located within terrace V of the Vistula Valley (Toruñ Basin) with the formation of lower terraces in the Late Glacial period.
The re search pre sented in this pa per fo cuses on the ket tle hole func tion ing in the ag ri cul tural land scape of the I³awa Lake Dis trict in the area of Mor¹g mo raines (Jurki site, NE Po land). This study aims to ana lyse the ef fect of palaeoenvironmental changes on the sedimentological and geo chem i cal prop er ties of ket tle hole sed i ments. Based on the re sults ob tained, com -bined with palaeobotanical and ra dio car bon data, the lo cal palaeo environment and the hu man im pact on some of the land -scape com po nents were de ter mined. This is a con tin u a tion of the multiproxy stud ies fo cus ing on ket tle holes of dif fer ent gen -e sis and dif f-er -ent land us-e, lo cat-ed n-ear th-e main stag na tion lines of the Vistulian ice sheet (Karasiewicz et al., 2014a, b).
STUDY AREA
The ket tle hole stud ied in the Jurki vil lage is of a small form (bot tom – 40 x 60 m, the di rect catch ment area – 4.6 ha). It is lo -cated ca. 4 km north of Mor¹g (53°58’N and 19°58’E; the I³awa Lake Dis trict, NE Po land; Fig. 1). The site is lo cated at the south -ern side (dis tal part) of the re ces sional end mo raines from the Pom er a nian Phase of the Vistulian Gla ci ation, the height of which lo cally ex ceeds 200 m a.s.l. (Roszkówna, 1955; Kara -siewicz, 2006a, b). The mo raines form a belt ex tend ing from east
to west with a width rang ing from 2 to 4.5 km. Roszkówna (1955) dis tin guished three zones within the belt: the in ter nal (till) zone, the cen tral zone (built of gla cial sand and flu vio gla cial de pos its), and the outer (pushed) zone. The in te rior of the fron tal mo raines is built up of pushed flu vio gla cial de pos its, lo cally with till on the sur face. The re search by Karasiewicz (2006a, b) re vealed that the in ter nal struc ture of the Mor¹g mo raines is glaciotectonically dis turbed, and the ar range ment of mo raine belts is con nected with lobal-os cil la tory dis ap pear ance of the con ti nen tal ice sheet in this zone. It is dif fi cult to de ter mine the south ern (outer) range of the Mor¹g mo raines, which of ten smoothly turn into a hilly mo -raine pla teau (Karasiewicz, 2006a, b).
The or i gin of the ket tle hole stud ied is most likely con nected with the melt ing of a dead-ice block in mo raine de pos its, hence the sur round ings and sub stra tum of this landform is dom i nated by de pos its of sand, gravel, and boul ders of end mo raines. Col lu -vial de pos its are found in the lower parts of the slopes, while the bot tom of the ket tle hole is filled with biogenic sed i ments. In the past, the en tire di rect catch ment of the ket tle hole stud ied was used for ag ri cul ture, while at pres ent, land use is var ied. Young stands of oak and spruce trees oc cur along the north ern and east ern edges of the de pres sion: ar a ble fields in the south, and mead ows and pas tures in the west. The bot tom of the ket tle hole is over grown with shrubs and birch and wil low trees. The groun -dcover is dom i nated by Sphag num peat, moss peat and sedges.
METHODS
Sam pling. In to tal, 18 bore holes were drilled within the di
-rect drain age ba sin and in the bot tom of the ket tle hole in the Jurki vil lage. Based on the bore holes, 3 cores with an in tact struc ture were col lected by a Living stone’s probe mod i fied by Wiêckowski (1989) in the cen tral (JuI), north ern (JuII), and
south ern (JuIII) parts of the de pres sion (Fig. 1). In ad di tion, 4 soil
pits were made on the slopes of the ket tle hole. Their lo ca tion closely cor re sponded with the two main types of land use in the drain age ba sin: ag ri cul tural (pro files A and B) and for est (pro -files C and D). The sam ples were ana lysed us ing the se lected sedimentological, geo chem i cal, and palaeobotanical meth ods de scribed be low.
SEDIMENTOLOGICAL AND GEOCHEMICAL ANALYSIS Grain-size com po si tion. Sam ples col lected from the slope
sed i ments (pro files A–D, 42 sam ples) were dried and sieved us ing a set of sieves with di am e ters rang ing from 10 to 0.1 mm. The finer frac tion was de ter mined us ing a Fritsch la ser par ti cle sizer Analysette 22. For each sam ple, tex tural pa ram e ters such as mean di am e ter (Mz) and sort ing (s1) were cal cu lated ac cord
-ing to Folk and Ward (1957) – Gradistat soft ware (Blott and Pye, 2001).
Geo chem is try. Anal y ses were per formed on sam ples col
-lected from two cores, which re f-lected the dif fer en ti a tion of the sed i ment se quence i.e. from the cen tral part of the ket tle hole (JuI – thick ness of 4.20 m; 55 sam ples) and from its south ern
pe riph er ies (JuIII – 1.70 m; 33 sam ples), as well as from two out
crops on the slopes (pro file A – 1.50 m; and D – 1.40 m: 22 sam ples). The fol low ing pa ram e ters were de ter mined in the bio -genic and min eral de pos its:
–
the con tent of or ganic mat ter loss on ig ni tion at a tem -per a ture of 550°C for 3 h;–
re ac tion (pH) by the potentiometric method;The to tal con tent of Ca, Mg, Fe, and Mn was de ter mined by atomic ab sorp tion spec trom e try (AAS); Na and K con tent was de ter mined by emis sion spec trom e try (ES) af ter treat ment of sam ples with HNO3 + H2O2 mix ture on a sand bath. The con tent
of terrigenous sil ica was de ter mined in the sed i ments of core JuI and JuIII us ing a method pro posed by Apolinarska et al.
(2012) - by di ges tion of sam ples us ing aqua regia and NaOH af ter ig ni tion at 550°C.
Sta tis ti cal anal y sis (JuI core only). Hi er ar chi cal clus ter
anal y sis was used to iden tify the geo chem i cal zones (Past soft -ware). The soft ware pack age Statistica 9.0 (Statsoft Inc.) was used to draw scat ter plots be tween se lected pa ram e ters of the sed i ments.
PALAEOBOTANICAL ANALYSES
Pol len anal y sis. A to tal of 72 sed i ment sam ples (JuI – 45
sam ples and JuIII – 27 sam ples) of 1 cm3 vol ume at a res o lu tion
of 5–10 cm were ex am ined paly no logi cal ly, and based on the stan dard pro ce dures were treated with 10% HCl, 10% KOH, 40% HF, and Erdtman’s acetolysis (Berglund and Ralska --Jasiewiczowa, 1986). A known num ber of in di ca tor spores of Lycopodium (Stockmarr, 1971) was added to each sam ple in or der to de ter mine pol len con cen tra tion. The Polpal soft ware for
Win dows (Nalepka and Walanus, 2003) was used to ana lyse
the re sults.
307
Fig. 1. Map of the study area
A – lo ca tion re lated to the ex tent of the Vistula Gla ci ation, of the Pom er a nian Phase in Po land; B – de tailed lo ca tion on a top o graphic map; C – view of the ket tle hole stud ied from the west
Macroremain anal y sis. A to tal of 43 sed i ment sam ples (10
sam ples from the bot tom of the pro file did not con tain plant macroremains) were col lected in close cor re la tion with palynological sam pling (JuI core). They were taken at the fol
-low ing in ter vals: ev ery 5 or 10 cm (de pend ing on the lithological char ac ter is tics) along the re main ing 3.25 m up to the top most layer. The sam ples were mac er ated ac cord ing to a stan -dard pro ce dure (adopted by e.g., Stachowicz-Rybka, 2011).
Ra dio car bon dat ing. One bulk sam ple from the JuI core
(0.25 m b.g.l.) was dated. The anal y sis was car ried out at the Ra dio car bon Lab o ra tory, the Silesian Uni ver sity of Tech nol ogy in Gliwice (Po land). The data were cal i brated us ing the OxCal
v. 4.2.2 soft ware (Bronk Ramesy, 2009).
RESULTS
Li thol ogy and chro nol ogy. Based on the field re search
con ducted on the sed i ments of the di rect catch ment of the ket -tle hole stud ied, it was found that sand, gravel, and boul ders of end mo raines dom i nate in the sub strate, of ten interbedded with flow till of a small thick ness. On the other hand, the thick ness of col lu vial de pos its and till age diamicton (ag ri cul tural colluvia) in -creased to wards the bot tom of the de pres sion. Those were mainly sand de pos its, with an ad di tion of ca. 10% of silt. The frac tion of gravel and clay ac counted for a to tal of up to 10%. The me dian (Mz) for de pos its of pro file A ranged from 1.53 to 4.08 phi; the mean was 2.35 (Figs. 2 and 3). Sim i lar re sults were ob tained for other pro files (Mz from 2 to 3 phi). The sed i -ments ana lysed were poorly sorted (s1 1.42–2.94) and dif fered
from each other in col our and en rich ment with or ganic mat ter. Bur ied soil ho ri zons were iden ti fied in pro file A at depths of 0.80–0.90 m and 1.10–1.20 m (Fig. 3). The thick ness of col lu -vial de pos its in the pro files ana lysed (A–D, Fig. 2) was >0.80 m, and the max i mum was 1.30 m. In the case of slopes with north -ern (pro file A) and south -ern (pro file C) ex po sure, the de pos its are eas ily iden ti fied be cause they cover the biogenic sed i ments (peat). De spite the fact that all soils rep re sented by pro files A–D were de vel oped from slope sed i ments, their prop er ties dif fered mark edly. There fore, they were clas si fied into var i ous soil units ac cord ing to WRB sys tem (IUSS Work ing Group WRB, 2015), i.e.: acidic soils hav ing a umbric ho ri zon (pro files A and C) as Haplic Umbrisols (Colluvic), soils more rich in base cat ions with mollic ho ri zon (pro file B) as Haplic Phaeozems (Colluvic), and oth ers (pro file D) as Colluvic Regosols (Figs. 2 and 3).
Min eral-or ganic gyttja was found at the floor (bot tom) of the ket tle hole, cov ered with sedge and moss peat (Dystric Histosols; Fig. 2). The max i mum thick ness of or ganic sed i -ments was de ter mined in the cen tral part of the ket tle hole – 4.15 m (JuI). In the sec ond core (JuII), lo cated sev eral metres
away from the first one to the south-east, biogenic sed i ments had a thick ness of 3.56 m. Biogenic sed i ments in the third core (JuIII; lo cated at the south ern edge of the bot tom) had a thick
-ness of only 1.20 m and oc curred in the form of peat with a high con tent of min eral mat ter (Fig. 2).
The stra tig ra phy of the sed i ment se quence in the ket tle hole stud ied was based on the palynological anal y sis per formed in the JuI core. More over, the JuIII core com prised Early Ho lo cene
de pos its (Fig. 4). The seven lo cal pol len zones were dis tin -guished (L PAZ – lo cal pol len as sem blage zones; Fig. 4). They re lated to the de vel op ment of veg e ta tion in north-cen tral Po land
(Noryœkiewicz, 1987, 2013; Ralska-Jasiewiczowa et al., 1998). More over, the his tory of lo cal veg e ta tion was com pleted with the re sults of macroremains anal y sis (in to tal, 6 lo cal macro fossil as sem blage zones – L MAZ; Fig. 5). A syn thetic de scrip tion of the stra tig ra phy and li thol ogy of the de pos its stud ied cor re lated with L PAZ and L MAZ is pre sented in Fig ure 6. The fol -low ing chronozones were dis tin guished: 3.40–4.20 m – the Late Gla cial (the top sed i ment sam ple was char ac ter ized by mixed taxa of the Late Gla cial and the Ho lo cene; Fig. 4);
3.20–3.40 m – a hi a tus from the Preboreal, Bo real and Early At -lan tic pe ri ods; 2.90–3.20 m – the Late At -lan tic; 0.0–2.80 m – the Subboreal and Subatlantic.
In ad di tion to well-pre served sporomorphs, the Late Gla cial de pos its (3.40–4.20 m) in the JuI pro file con tained re worked
ma te rial (Ilex, Se quoia, Hystrix). On the other hand, the over ly -ing seg ment 3.20–3.40 m com prised pol len-free de pos its with cor roded fern spores and frag ments of bro ken FeMn con cre tions. The up per part of the re main ing sed i ment was char ac ter
-309 D d n a A s eli f or p f o s ei tr e p or p t n e m i d e s l a c i m e h c o e g e ht g n i w o h s s m ar g ai D . 3 . gi F
g i
311
g i
ized by a high con tent of sporomorphs, cor roded to a lesser or greater ex tent (e.g., the de graded curve – Fig. 4). There fore, the re sults of pol len anal y sis for pro files JuI and JuIII are dif fi cult
to in ter pret.
GEOCHEMISTRY
Slope sed i ments. Sed i ments of pro files A and D are dis tin
-guished by a vary ing con tent of or ganic mat ter (A – 1.5–18.0%; D – 1.4–3.3%) and a low con tent of Ca (0.01–3.84 mg·g–1 and 0.06–0.31 mg·g–1, re spec tively; Fig. 3). The high est con tent of OM was de ter mined in the bur ied soil ho ri zons (pro file A; 0.80–0.90 m and 1.10–1.20 m). The con tent of po tas sium (up to 5.3 mg·g–1) and mag ne sium (up to 4.6 mg·g–1) was higher in the sed i ments of pro file A com pared to pro file D (ac cu mu la tion in the deeper min eral sed i ment layer). On the other hand, sed i ments of the lat ter pro file were char ac ter ized by a higher con -tent of such met als as Mg, Fe, Mn, and Zn (Fig. 7). The range of pH val ues var ied greatly (pro file A – 4.2–7.7; pro file D – 6.4–8.1). The low est pH val ues were re corded in col lu vial sed i -ments of pro file A, and the high est in the lev els con tain ing CaCO3 (up to 0.8%; Fig. 3).
Bot tom sed i ments. Prop er ties of the bot tom sed i ments of
the ket tle hole stud ied were de scribed based on the sam ples col -lected from two cores at sites JuI and JuIII. The at ten tion was fo
-cused mainly on the for mer due to its lo ca tion in the cen tral part of the bot tom and a com plete se quence of bot tom sed i ments.
The seven geo chem i cal zones (from JuI/I to JuI/VII) were
iden ti fied in the JuI core by hi er ar chi cal clus ter anal y sis (Fig. 7).
As shown in Ta ble 1, the zones dif fer sig nif i cantly in their chem i
-cal prop er ties. The most im por tant fea tures of these zones are de scribed be low.
The JuI/I zone (4.10–4.20 m; sand, or ganic silt), which rep re
sents the bot tom layer of the sed i ment se quence, was char ac ter ized by a slightly al ka line re ac tion (pH 7.3–7.9) and by con sid er -able en rich ment with or ganic mat ter (OM 4.6–14.3%). The con -tent of OM was de ter mined as a loss on ig ni tion and there fore the val ues ob tained may be some what over stated (as in JuI/II) due to
the very high con cen tra tion of car bon ates. The zone was dis tin -guished by the max i mum (in re la tion to the whole pro file) Fe (274 mg·g–1) and Mn con tent (10.2 mg·g–1) as well as a very high con -tent of SiO2ter (up to 64.2%), Ca (up to 212 mg·g–1), and CaCO3
(up to 30%) (Fig. 7). Low val ues of geo chem i cal in di ca tors, i.e. Na:K (0.10–0.12), Ca:Fe (0.1–3.5) and Fe:Mn (28–68) were de -ter mined. A rel a tively high ra tio of Ca:Mg (7–36) may be con -nected with a high con tent of car bon ates.
The JuI/II zone (3.70–4.10 m; min eral gyttja) had a lower
con tent of OM (min i mum for the whole pro file – 2.5%) and a higher con tent of SiO2ter com pared to JuI/I (up to 67.3%). The
max i mum val ues for the whole pro file were re corded for Ca (up to 249 mg·g–1), CaCO3 (46.5%), K (3.3 mg·g–1), Mg
(7.2 mg·g–1), Na (0.22 mg·g–1), and pH (8.2). Fur ther more, a sig nif i cant re duc tion in the con tent of Fe and Mn was de ter -mined. The in di ca tors Ca:Mg and Fe:Mn sig nif i cantly in creased (up to 43 and 120, re spec tively), and the Ca:Fe ra tio had the max i mum value through out the pro file (15.8). Val ues of the Na:K ra tio were sim i lar to JuI/I.
Sed i ments in the JuI/III zone (3.40–3.70 m; min eral gyttja with
Fe-Mn con cre tions) were mod er ately rich in or ganic mat ter (OM 6.9–17.0%). Com pared to JuI/II, a de crease in pH val ues and in
the con tent of SiO2ter, Ca, CaCO3, K, Mg, and Na was de ter
-mined, along with a very large in crease in the con tent of Fe (up to
Fig. 6. Chronozones marked in the JuI sed i ment core
313 g i F . 7 .Geo chem i calprop er ties fo the uJ I and uJ I IIcoresed i ments l a c i g o l o h t i L de scrip tion sa f orFig ure 2
245 mg·g–1), Mn (up to 8.6 mg·g–1), and Zn (up to 129 mg·g–1). In this zone, a sig nif i cant de crease in the val ues of Ca:Fe (min. <0.1), Fe:Mn (28–71) and Ca:Mg (min. <1) was re corded. Val -ues of the Na:K ra tio were sim i larly low as in older ho ri zons.
The JuI/IV zone (3.20–3.40 m; min eral-or ganic gyttja) was
dis tin guished by the pres ence of slightly acid de pos its (pH 6.4–6.7) with a highly var ied con tent of or ganic mat ter and terrigenous sil ica, i.e. 6 and 81% (the pro file’s max i mum) in the floor and 48 and 40% in the top, re spec tively. Com pared to JuI/III, a sig nif i cant de crease in the con tent of Ca (up to
0.2 mg·g–1), Mn (up to 0.1 mg·g–1), and Mg (up to 3.3 mg·g–1) was de ter mined in this zone, and there was a ma jor in crease in the con tent of Zn (max i mum for the pro file – 205 µg·g–1). Fur -ther more, the max i mum val ues of the Fe:Mn ra tio (210) were de ter mined and there was a con sid er able de crease in the val -ues of Fe:Ca, Na:K, and Ca:Mg ra tios, which were equally low as in the JuI/III zone.
The JuI/V zone (2.60–3.20 m; coarse de tri tal gyttja) was dis
-tin guished by a sud den in crease in the or ganic mat ter con tent (OM 86–89%), with a si mul ta neous ma jor de crease in the con -tent of terrigenous sil ica (SiO2ter 1.3–4.5%), K
(0.07–0.12 mg·g–1), and Mg (0.3–1.4 mg·g–1). The con tent of Zn re mained at a level above 100 µg·g–1 (Fig. 7). The pH val ues ranged from 5.7 to 5.8, which in di cated acid i fi ca tion of the en vi
-ron ment. Con trary to the Fe:Mn ra tio (85–179), val ues of Na:K (0.6–1.2), Ca:Mg (1–46) and Ca:Fe (0.1–1.7) ra tios in creased. The JuI/VI zone (0.35–2.60 m; coarse de tri tal gyttja at the
floor, sedge peat and mosssedge peat at the top) was dis tin -guished by a very high con tent of or ganic mat ter and a small con tent of terrigenous sil ica (the min i mum value of 0.1%). These pa ram e ters var ied, how ever, to a larger ex tent com -pared to JuI/V (OM 62–93%, SiO2ter 0.1–11%). The sed i ments
were acidic (pH 5.1–5.8) with par tic u larly poor con cen tra tions of po tas sium and mag ne sium, which oc curred with the min i mum val ues in this zone (K 0.05 mg·g–1, Mg 0.3 mg·g–1). In the up per -most layer of the zone, the con cen tra tions of Pb (up to 52.9 µg·g–1) and Zn (up to 90.3 µg·g–1) sig nif i cantly in creased. Fur ther more, a small in crease in the val ues of Ca:Fe (1.3–6.5), Ca:Mg (19–53), and Na:K (up to 1.3 – the max i mum value in the pro file) and a con sid er able de cline in val ues of the Fe:Mn ra tio (14–68) was ob served.
The JuI/VII zone (0.0–0.35 m; peat) was char ac ter ized by a
wide range of or ganic mat ter con tent (35–95%). With re spect to JuI/VI, a sig nif i cant in crease in the con tent of SiO2ter (up to
59.1%), Mg (0.4–2.2 mg·g–1), and K (0.3–1.5 mg·g–1) was de ter -mined. Fe and Mn reached their pro file min ima (2.7 and 0.06 mg·g–1, re spec tively). The con tent of lead and zinc largely var ied (Pb 10.0–62.5 µg·g–1; Zn 16.3–66.3 µg·g–1) and sig nif i
-T a b l e 1 Sta tis ti cal mea sures of the ana lysed sed i ment pa ram e ters (mean ± stan dard de vi a tion, range), JuI core
Pa ram e ter Lo cal geo chem i cal zones
I (n = 2) II (n = 5) III (n = 5) IV (n = 5) V (n = 11) VI (n = 29) VII (n = 7) OM [%] 9.5 ±6.8 (4.6–14.3) 3.7 ±0.9 (2.5–4.9) 9.4 ±5.1 (6.9–17.0) 9.7 ±23.7 (5.8–47.6) 87.1 ±1.4 (85.8–89.1) 90.2 ±5.7 (61.6–92.9) 70.5 ±22.6 (35.4–95.0) SiO2ter [%] 46.1 ±25.7 (27.9–64.2) 63.0 ±6.4 (52.1–67.3) 46.8 ±20.7 (21.0–62.1) 70.1 ±23.9 (39.5–80.9) 2.7 ±1.3 (1.3–4.5) 1.4 ±2.4 (0.1–11.0) 12.5 ±20.8 (2.7–59.1) CaCO3 [%] 24.6 ±7.7 (19.2–30.0) 32.5 ±13.4 (16.7–46.5) 4.0 ±2.4 (1.4–6.2) 0.48 ±0.56 (0.11–1.12) – – – Ca [mg·g–1] 117 ±133 (23.0–212) 145 ±67.0 (104–249) 4.4 ±13.2 (0.5–26.7) 0.6 ±6.5 (0.2–11.5) 15.2 ±9.6 (1.6–27.4) 23.8 ±2.7 (16.3–28.2) 1.9 ±3.1 (0.1–8.3) Mg [mg·g–1] 4.7 ±1.7 (3.5–5.9) 6.6 ±0.5 (5.8–7.2) 4.8 ±1.6 (3.3–6.3) 3.4 ±1.1 (2.2–4.3) 0.7 ±0.5 (0.5–1.7) 0.6 ±0.2 (0.3–1.4) 0.8 ±0.8 (0.4–2.2) K [mg·g–1] 1.3 ±1.2 (0.4–2.1) 2.1 ±0.8 (1.1–3.3) 1.3 ±0.6 (0.7–1.8) 1.8 ±0.7 (1.1–2.4) 0.1 ±<0.1 (0.07–0.12) 0.1 ±0.1 (0.05–0.31) 1.0 ±0.4 (0.3–1.5) Na [mg·g–1] 0.1 ±0.1 (0.05–0.21) 0.2 ±<0.1 (0.19–0.22) 0.1 ±0.1 (0.08–0.17) 0.2 ±<0.1 (0.14–0.17) 0.1 ±<0.1 (0.05–0.15) 0.1 ±<0.1 (0.01–0.16) 0.1 ±0.0 (0.08–0.16) Fe [mg·g–1] 167 ±151 (60.3–274) 30.6 ±10.2 (15.8–43.5) (122–245)166 ±61.5 (20.0–35.8)26.2 ±8.6 (14.4–35.2)20.7 ±7.5 5.7 ±3.4 (3.5–20.3) 6.1 ±4.3 (2.7–13.1) Mn [mg·g–1] 5.5 ±6.5 (0.9–10.2) 0.3 ±0.1 (0.2–0.4) 2.7 ±3.7 (1.7–8.6) 0.1 ±<0.1 (0.11–0.17) 0.2 ±<0.1 (0.16–0.20) 0.2 ±0.1 (0.08–0.51) 0.1 ±0.1 (0.06–0.27) Pb [µg·mg–1] 25.0 ±21.3 (10.0–40.1) 26.9 ±6.0 (22.7–26.3) (10.0–24.5)17.9 ±7.3 (10.0–25.1)19.5 ±7.8 (10.0–23.2)14.9 ±9.1 (10.0–52.9)14.1 ±11.9 (10.0–62.5)30.2 ±18.4 Zn [µg·mg–1] 76.2 ±21.1 (61.3–91.1) 43.6 ±15.2 (26.3–60.8) 101 ±21.9 (85.1–129) 141 ±56.2 (102–205) 140 ±34.4 (109–200) 12.5 ±26.4 (2.0–90.3) 34.3 ±19.8 (16.3–66.3) pH 7.6 ±0.4 (7.3–7.9) 8.0 ±0.1 (7.9–8.2) 7.1 ±0.6 (6.8–6.3) 6.6 ±0.2 (6.4–6.7) 5.7 ±<0.1 (5.7–5.8) 5.4 ±0.2 (5.1–5.8) 4.5 ±0.5 (3.8–5.0) Na:K 0.1 ±<0.1 (0.10–0.12) 0.1 ±<0.1 (0.07–0.17) 0.1 ±<0.1 (0.09–0.12) 0.1 ±<0.1 (0.07–0.13) 0.8 ±0.2 (0.6–1.2) 0.7 ±0.3 (0.1–1.3) 0.1 ±0.1 (0.1–0.3) Fe:Mn 48 ±29 (28–68) 105 ±21 (69–120) 56 ±24 (28–71) 183 ±39 (138–210) 123 ±38 (85–179) 33 ±17 (14–68) 51 ±27 (14–86) Ca:Mg 21 ±21 (7–36) 25 ±12 (16–43) 2 ±2 (<1–4) 2 ±3 (<1–5) 34 ±17 (1–46) 40 ±7 (19–53) 8 ±8 (<1–23) Ca:Fe 1.8 ±2.4 (0.1–3.5) 6.6 ±5.6 (2.7–15.8) 0.1 ±0.1 (<0.1–0.1) 0.2 ±0.3 (<0.1–0.6) 1.1 ±0.6 (0.1–1.7) 4.3 ±1.3 (1.3–6.5) 0.9 ±0.9 (<0.1–2.1)
cantly dropped in the last 10 cm of the roof. A large de crease in pH val ues to wards the roof of sed i ments was ob served, which were very acidic at the sur face (pH 3.8). Val ues of geo chem i cal in di ces, ex cept for Fe:Mn (14–86), were much lower com pared to JuI/VI.
Fig ure 8 pres ents scat ter plots be tween the con tent of terrigenous sil ica (SiO2ter) and the con tent of or ganic mat ter (OM)
and se lected met als in the whole JuI pro file. A highly sig nif i cant
neg a tive cor re la tion be tween SiO2ter and OM was re corded (r
value –0.944, p = 0.000), whereas a sig nif i cant pos i tive cor re la -tion was found only for Na, K, Mg, Fe, Pb, Zn – el e ments closely con nected with lithological con di tions of the drain age ba sin. K and Mg dem on strated the stron gest cor re la tion with SiO2ter (r val
-ues 0.922 and 0.859, re spec tively; p = 0.000). These met als are gen er ally more strongly sorbed by sed i ments and there fore sub -ject to pas sive mi gra tion to gether with min eral and or ganic colloids (Borówka, 1992; Franz et al., 2006).
The bot tom part of pro file JuIII was built of min eral de pos its
(loam), which are rich in CaCO3 (ca. 16%, pH 7.6–8.0) and all the
met als ana lysed (Fig. 7). Paludal sed i ments of JuIII (1.20–0.0 m)
were dis tin guished by a sig nif i cant het er o ge ne ity of all the pa -ram e ters ana lysed. A con sid er able en rich ment in or ganic mat ter (up to 83%), Ca (up to 32 mg·g–1), Mn (up to 3.4 mg·g–1), Zn (up to 163 µg·g–1), and Pb (up to 61 µg·g–1) was ob served from the depth of 0.65 m to wards the up per part of pro file, with the con tent of terrigenous sil ica <40%. Com pared to sur face lay ers within the range of 0.65–1.2 m, the con tent of OM (12–69%), Ca (0.1–15.8 mg·g–1), Mn (0.1–0.3 mg·g–1) de creased, while the
con tent of SiO2ter in creased (up to 73%), Mg (1.9–8.3 mg·g–1), K
(4.1–9.5 mg·g–1), and Fe (10.1–47.2 mg·g–1) (Fig. 7).
DISCUSSION
The or i gin of the ket tle hole stud ied is con nected with the melt ing of a dead-ice block and the dis ap pear ance of long-term per ma frost. Ac cord ing to van Loon et al. (2012), the per ma frost mostly de vel oped in the icefree zone that ap peared af ter the re ces sion of the ice sheet. Con sis tent with the views of B³aszkie -wicz (2008, 2011), it was likely that the melt ing of a bur ied deadice block pro ceeded rel a tively quickly in the ab sence of wa -ter run off from the ket tle hole stud ied and the pres ence of thermokarst pro cesses. Sed i ment ac cu mu la tion of the first lo cal geo chem i cal zone JuI/I prob a bly still oc curred in the periglacial
con di tions of the ini tial cold lake, which may be shown by e.g., a low con cen tra tion of Ca (Fig. 7). Then the per ma frost un der went a grad ual deg ra da tion, which re sulted in a sig nif i cant in ten si fi ca -tion of chem i cal and me chan i cal de nu da -tion pro cesses in the drain age ba sin (the max i mum con tent of Ca, CaCO3, K, Mg, and
Na) in JuI/II (Ta ble 1, Figs. 7 and 8). A layer of min eral gyttja was
lo cated at a depth of 3.70–3.40 m, which tes ti fies to the fur ther evo lu tion of the small lake (JuI/III). The layer was char ac ter ized by
a sig nif i cant en rich ment in terrigenous sil ica, the lack of car bon -ates, and the pres ence of ferruginous-man ga nese con cre tions. The pres ence of the lat ter can prob a bly be as so ci ated with
315
Fig. 8. Scat ter plots of the terrigenous sil ica (SiO2ter) con tent ver sus the con tent of or ganic mat ter (OM)
post-sed i men ta tion pro cesses, i.e. diagenesis of de pos its in the con di tions of par tial de hy dra tion and/or wa ter-level fluc tu a tions. This sug ges tion was also sup ported by the pres ence of a hi a tus above the ana lysed layer, and the ma te rial con tain ing mixed Late Gla cial and Ho lo cene taxa (depth 3.40 m; Fig. 4). Min eralor ganic gyttja at a depth of 3.20–3.40 m did not con tain pol -len. A strati graphi cal gap oc curred dur ing the Preboreal, Bo real, and Early At lan tic pe ri ods. Per haps the res er voir was not com -pletely sealed and in the Early Ho lo cene was drained along with low er ing the ground wa ter level? It is pos si ble in this time that the ba sin was dry. The likely rea son for the pres ence of sed i ments with no pol len and macroremains was the des ic ca tion of the de -pres sion’s bot tom, which could con trib ute to the wind de fla tion of de pos its, and con se quently the de struc tion of pol len grains. There fore, the in ter pre ta tion of geo chem i cal in di ca tors for JuI/IV,
which is char ac ter ized by e.g., pro file max ima for Zn and the Fe:Mn ra tio (Ta ble 1 and Fig. 7), was in this case very lim ited. A sim i lar case was de scribed by Mendyk et al. (2015) based on re -search con ducted in the drain age ba sin of Lake Sumowskie (Brodnica Lake Dis trict, north-cen tral Po land). If it is as sumed that the ac cu mu la tion of sed i ments with a hi a tus be gan in the Preboreal, the wa ter-level low er ing in the ket tle hole ana lysed can also be re lated to sim i lar trends re ported from other re gions of Po land (e.g., Niewiarowski, 1989, 1995; Starkel et al., 1998; Twardy et al., 2010; Hirsch et al., 2015).
As shown by the palynological anal y sis, the bot tom layer of sed i ments from the pro file JuI, cov er ing the geo chem i cal lev els
I, II, and III, should be re lated to the rel a tively cold Late Gla cial pe riod (Fig. 4). At that time, trees were rep re sented only by pine (Pinus) and birch (Betula), and they were ac com pa nied by heliophilous shrubs and low shrubs (Juniperus, Salix, Betula
nana t. and oc ca sion ally Hippophae rhamnoides). In ad di tion,
plant in di ca tors of cold gla cial pe ri ods oc curred (Dryas
octopetala, Selaginella selaginoides and Helianthemum). The
re de pos ited taxa (of Qua ter nary or i gin and Neo gene, and frag ments of dinoflagellates – Hystrix) were also pres ent in rel a -tively large num bers. They prob a bly came from the eluviation of older de pos its de rived from the drain age ba sin of the ket tle hole, which was pos si ble be cause of a rather loose veg e ta tion cover. Macroremains have not been pre served in the sed i -ments of these zones.
The pres ence of coarse de tri tal gyttja de pos its JuI/V (the
Late At lan tic and Early Subboreal) in di cated a change in the sed i men ta tion pro cess and the pre vail ing telmatic con di tions in the de pres sion. How ever, due to the pres ence of the above men tioned hi a tus, it was not pos si ble to de ter mine the be gin -ning of the coarse de tri tal gyttja ac cu mu la tion. A low con tent of terrigenous sil ica and high val ues of Na:K, Ca:Mg, and Ca:Fe in di ces may in di cate the dom i nance of chem i cal de nu da tion pro cesses in the drain age ba sin over me chan i cal de nu da tion (Ta ble 1 and Fig. 7). In such con di tions, a wide range of Fe:Mn val ues may re flect the vari able re dox po ten tial as so ci ated with wa terlevel fluc tu a tions (Borówka, 1992; Co hen, 2003). Sim i -larly to JuI/IV, the geo chem i cal zones ana lysed were dis tin
-guished by a high con tent of Zn (up to 200 mg·g–1), caused by bot tomup postsed i men ta tion mi gra tion in the acidic en vi ron -ment (in clud ing groundwaters). Tak ing into ac count the re sults ob tained by Karasiewicz et al. (2014b), de spite the lack of a clear re cord in the di a grams of pol len and macroremains, one can not ex clude the ef fect of Zn bioaccumulation.
Anal y sis of plant re mains from a depth of 3.00–3.25 m (L MAZ JuI-1; Fig. 5) showed that in the pro cess of shallowing, the
sur face of the wa ter body was cov ered with a Lemnatea pleuston com mu nity, the main com po nent of which was Lemna
trisulca. The pres ence of rare fruits of Lemna trisulca in the top
part of the zone sug gests in creased tro phy and cal cium car bon
-ate con tent in the wa ter res er voir (Szoszkiewicz et al., 2010), but in the de posit there was no CaCO3. This could have oc
-curred when the en vi ron men tal con di tions did not fa vour the pre cip i ta tion of cal cium car bon ate. Urtica dioica oc curred along the shores in ni tro gen-rich wa ter logged places. Pe ri od i cally emerged, highly eutrophic places were over grown with
Ranunculus sceleratus. A lack of tree re mains and the pres
-ence of Lactuca serriola – a spe cies oc cur ring in dry and sun lit hab i tats – may in di cate the sup ply of ma te rial from places lo cated far ther from the shores of the wa ter body. This cor re -sponded to L PAZ JuI-3 (Ti-Ul 2.70–3.20 m; Fig. 4) where pol len
grains have traces of in ten sive cor ro sion and pol len spec tra are dis tin guished by a large num ber of Tilia pol len, which is rather un usual in the study area (Kupryjanowicz et al., 2004; Ba³aga and Chodorowski, 2006). Lin den pro duces rather large amo -unts of pol len, but the grains are rel a tively large and heavy (Dyakowska, 1959), hence the ge nus is rather underrepre sented in “pol len rain” (Œrodoñ, 1991). Nev er the less, sporo -derm of lin den pol len is rel a tively re sis tant to the de struc tion, which means that they can be iden ti fied even when they are heavily dam aged; this could ex plain their over-rep re sen ta tion in the sed i ment (Ba³aga and Chodorowski, 2006). In the same seg ment of sed i ment, there were sporomorphs and NPP (non pol len palynomorphs) com ing from the preQua ter nary sed i ments (in clud ing, e.g., se quoias, Neo gene spores, and dino -flagellates Hystrix – ma rine or gan isms – JuIII; Fig. 4), which
showed the trans port of older ma te rial from the drain age ba sin sur round ing the peat bog.
The Late Subboreal and the Early Subatlantic were rep re -sented by ge net i cally di verse sed i ments of JuI/VI, i.e. coarse de
-tri tal gyttja at the bot tom part and sedge peat in the top (Fig. 6). Based on the anal y sis of geo chem i cal in di ca tors (Na:K, Ca:Mg, Fe:Mn), it can be con cluded that sed i men ta tion of these de pos -its oc curred in vary ing de nu da tion con di tions of the drain age ba sin (Ta ble 1; Figs. 7 and 8) and with con sid er able wa ter-level fluc tu a tions. The wa terlevel rise in the Early Subatlantic is gen -er ally re corded in lac us trine and peat-bog sed i ments of the young gla cial area in Po land (Kowalewski, 2014). Sim i lar changes were doc u mented in the pol len and macroremain di a -gram cre ated for pro file JuI (Figs. 4 and 5). They were par tic u
-larly well-vis i ble for L PAZ JI-6 (Qu-Ca-Fa), L MAZ JI-2 (Urtica
dioica-Carex paniculata), and JI-3 (Carex pseudocyperus-Carex
paniculata). A high con tent of Cyperaceae at a depth of 1.40 m
and Filicales monolete at a depth of 1.50 m was de ter mined in the pol len spec tra ob tained. The in crease in sedge pol len and the re-oc cur rence of Sparganium and Lemna may be cor re lated with a wa ter-level rise, and the pre vi ous fern con tent of sev eral dozen per cent age with peat des ic ca tion. A very high con tri bu tion of Carex paniculata and C. pseudocyperus fruits was de ter -mined in L MAZ JI-2 and JI-3 (Fig. 5). They sug gest a de vel oped
telmatic zone. This sit u a tion could be ac counted for by fa vour able hab i tat con di tions. In the con di tions of a more hu mid hab i -tat (depth of 1.90 m), large amounts of Carex nutlets (depth 2.20 and 1.70–1.80 m) and Cyperaceae pol len were pro duced (Fig. 4). It can be as sumed that an in crease in the quan tity of sedge nutlets in the macroremain ma te rial was af fected by diagenetic pro cesses (drain ing of sed i ment, par tial de com po si -tion of or ganic mat ter) which led to peat com pac -tion. A sim i lar phe nom e non, trig gered by a wa ter-level fall and doc u mented by a sud den in crease in the con tri bu tion of Filicales monolete, was re corded in sed i ments at many sites (e.g., Noryœkiewicz, 2006; Wysota and Noryœkiewicz, 2011; Gamrat et al., 2014).
Zone JuI/VII con sisted of de pos its ac cu mu lated in the Late
Subatlantic, the prop er ties of which largely re flected a strong hu man im pact. The high in ten sity of the catch ment de nu da tion may be proven by a higher con tent of terrigenous sil ica, Na, K,
and Mg as com pared to JuI/VI (Ta ble 1; Figs. 7 and 8). For com
-par i son, the sur face or ganic sed i ment oc cur ring in the mar ginal parts of the ket tle hole (pro file JuIII), with the stron gest ef fect of
slope de nu da tion, had a sig nif i cantly higher con tent of terrigenous sil ica, K, Mg, Pb, and Zn (Fig. 3). For this rel a tively thin (0.35 m) layer of sed i ments, a con sid er able re duc tion in pH val ues (to <4) to wards the top up per most layer was ob served, which to gether with the pres ence of Sphag num (par tic u larly on the sur face of the peat bog in its mar ginal part; Fig. 4) can in di -cate a tran si tion to wards ombrotrophy. It can be as sumed that the likely cause of this phe nom e non could be the ex po sure of the ground around the ket tle hole (prob a bly through de for es ta -tion), which in ten si fied the wa ter ero sion in the drain age ba sin and re sulted in an in creased sup ply of acidic soil or ganic mat -ter. No sup ply of ground wa ter and a rel a tively large in flow of mat ter from the catch ment area ob vi ously con trib ute to changes in the eco log i cal con di tions of the ket tle hole. It should be noted, how ever, that a small area and lo ca tion in the ag ri cul -tural land scape pre vent the de vel op ment into a typ i cal raised bog (Timmerman and Succow, 2001; Tobolski, 2003). Cer tain cor re spond ing events were doc u mented in the sed i ments of a peat bog in Tuchola For est by Lamentowicz et al. (2007). Ac -cord ing to the re sults of palynological anal y sis, the be gin ning of in ten sive ag ri cul tural landuse in the catch ment area was re -corded in sed i ments of JuI and JuIII at a depth of ca. 0.30 and
0.50 m, re spec tively (Fig. 4). Pol len grains of synanthropic plants were found in the pol len spec tra, i.e. ce re als in clud ing
Cerealia type and Secale cereale as well as Centaurea cyanus, Plantago lanceolata, Rumex, Ar te mi sia and Chenopodiaceae.
Sed i ments col lected from the mid dle part of the depth range of L PAZ JuI-6 (0.25 m) were AMS ra dio car bon dated at 360 ±40
BP; GDA-2400. Af ter cal i bra tion, per formed in the OxCal 4.2 ap pli ca tion, the av er aged date was de ter mined as 1543 yr AD. At that time, those were ar a ble lands, first con trolled by the Teu tonic Or der, and then gov erned by the ad min is tra tion of the Du -cal and East Prus sia. The com par i son of pro files JuI and JuIII
with other data from north east ern Po land (Wacnik, 2009, 2012) showed that pro file JuI did not pres ent a com plete pic ture of the
eco nomic changes in this area. Most likely, a hi a tus oc curred in the Subatlantic re cord at a depth of 0.30 m. The pol len re cord in the roof part of the sur face sam ple was char ac ter ized by lo cal en croach ment of birch on the pres ent-day area of the ket tle hole stud ied.
The anal y sis of macroremains in the up per part of the sed i -ments (0.0–0.10 m) of pro file JuI showed the pres ence of nu
-mer ous achenes of Betula sc. Albae and Carex elata as well as seeds of Comarum palustre (Fig. 5). This cor re sponded to a con tem po rar ily de vel oped tall-sedge com mu nity (Caricion
elatae) with nu mer ous birch trees in the vi cin ity. A very sim i lar
re cord is found in the up per most layer from pro file JuI, where
Betula pol len rep re sents over 90% of all sporomorphs, while
her ba ceous plants were rep re sented mostly by sedges (Cypera ceae pol len). It should be noted, how ever, that the anal -y sis of macroremains was con ducted onl-y in the sed i ments from the cen tral part of the peat bog (JuI), where Sphag num
suc ces sion has not yet been ob served.
It ap pears that slope pro cesses oc cur ring in the drain age ba sin re sulted in the for ma tion of col lu vial de pos its (ag ri cul tural diamicton – Sinkiewicz, 1998; Frielinghaus and Vahrson, 1998), which are up to sev eral dozen centi metres thick and cover a se quence of biogenic sed i ments (fos sil soils; pro files A and C, Figs. 2 and 3). This showed the ex is tence of a larger (com pared to its cur rent size) wa ter body, trans formed mostly by anthropogenic denudation.
The ex tent and in ten sity of the catch ment land use was also re flected in the pH of col lu vial de pos its (Fig. 3). In the case of longterm ag ri cul tural use (pro file A), the acid re ac tion of the de -pos its can be at trib uted to the prop er ties of ini tial sur face soil ho ri zons formed be fore the slope pro cesses were ac ti vated within the top up per most parts of the slopes (Smolska, 2005; Podlasiñski, 2013; Karasiewicz et al., 2014a; Œwitoniak, 2015). Sig nif i cant ac cu mu la tion of or ganic mat ter may act as the sec -ond fac tor re spon si ble for acid i fi ca tion (Markiewicz et al., 2015). Neu tral and slightly al ka line re ac tions (pro file D) can be ac -counted for by the in flow of ma te rial from the zone with the most se vere ero sion pro cesses, where car bon ate-rich, par ent rock soils are ex posed (Œwitoniak, 2014; Œwitoniak et al., 2016). The ef fect of soil lim ing as so ci ated with af for es ta tion of this part of the drainage basin also cannot be excluded.
CONCLUSIONS
Ver ti cal di ver si fi ca tion of the sedimentological and geo -chem i cal prop er ties of the de pos its in the ket tle hole stud ied largely cor re sponded to en vi ron men tal changes re con structed through palaeobotanical stud ies. The geo chem i cal re cord has been pre served in the bot tom and slope sed i ments of the ket tle hole as a re sult of both nat u ral (e.g., cli mate changes, hy dro graphic con di tions, veg e ta tion cover) and anthropogenic pro -cesses (land use) oc cur ring over the last sev eral thou sand years. This study showed that de spite the small size of the ket tle hole, its de pos its have ar chived local and supralocal palaeo -environmental changes.
Based on the re sults ob tained it was pos si ble to iden tify sev -eral postglacial stages re flect ing the his tory of palaeo -environmental changes in the ket tle hole and the sur round ing area. The first im por tant stage con sisted in the melt ing of a dead-ice block in per ma frost con di tions, fol lowed by the stage of a small, late gla cial lake, the sed i ments of which were de pos -ited be neath the pol len-free layer. The pres ence of this layer pro vides ev i dence for the chang ing hy dro log i cal con di tions, which re sulted in a strati graphic gap cov er ing sev eral thou sand years (from the Preboreal to the Mid dle At lan tic), and con se -quently a tem po rary dis ap pear ance of the wa ter body. In the sub se quent stage, limnic con di tions dom i nated again (min -eral-or ganic gyttja), fol lowed by telmatic con di tions af ter the lake ba sin was filled with sed i ments (coarse de tri tal gyttja). This led to the de vel op ment of a peat bog (sedge and sedge-moss peat de pos its). These de pos its con tain a re cord of wa ter-level fluc tu a tions dur ing the Subboreal and Subatlantic wet pe ri ods, and from the Mid dle Ages – a strong hu man im pact. In this con text, the re duc tion in the bot tom sur face of the ket tle hole stud -ied as a re sult of nat u ral and anthropogenic de nu da tion, as well as the strong acid i fi ca tion of the hab i tat, which re sulted in
Sphag num suc ces sion, ap pear par tic u larly important.
The au thors hope that their re search will con trib ute to a com pre hen sive re con struc tion of the postglacial de vel op ment of the Pol ish Low land, and the re sults may be used in com par a -tive studies.
Ac knowl edge ments. We wish to thank O. Juschus and
J. Forysiak for their valu able sug ges tions that im proved the qual ity of this pa per. Fund ing sup port for this re search was pro -vided by the Pol ish Min is try of Sci ence and Higher Ed u ca tion (grant no. N N306 282935).
REFERENCES
Apolinarska, K., Woszczyk, M., Obremska, M., 2012. LateWeichselian and Ho lo cene palaeoenvironmental changes in north ern Po land based on the Lake Skrzynka re cord. Boreas, 41: 292–307.
Ba³aga, K., Chodorowski, J., 2006. Pol len anal y sis from fos sil podzol soils within a dune at Kaczórki (Mid dle Roztocze, Po -land). Acta Palaeobotanica, 46: 245–254.
Berglund, B.E., Ralska-Jasiewiczowa, M., 1986. Pol len anal y sis and pol len di a grams. In: Hand book of Ho lo cene Palaeo ec ol ogy and Palaeohydrology (ed. B.E. Berglund): 455–496. John Wiley and Sons, Chichester.
Bilotta, G.S., Bra zier, R.E., Haygarth, P.M., 2007. Pro cesses af fect ing trans fer of sed i ment and colloids, with ero sion. Hy dro -log i cal Pro cess, 21: 135–139.
Blott, S.J., Pye, K., 2001. Gradistat: a grain size dis tri bu tion and sta tis tics pack age for the anal y sis of un con sol i dated sed i ments. Earth Sur face Pro cesses and Land forms, 26: 1237–1248. B³aszkiewicz, M., 2008. Wytapianie siê pogrzebanych bry³
martwego lodu w póŸnym glacjale i wczesnym holocenie a zdarzenia ekstremalne (in Pol ish). Landform Anal y sis, 8: 9–12. B³aszkiewicz, M., 2011. Tim ing of the fi nal dis ap pear ance of per
-ma frost in the cen tral Eu ro pean Low land, as re con structed from the evo lu tion of lakes in N Po land. Geo log i cal Quar terly, 55 (4): 361–374.
Borówka, R.K., 1992. The pat tern and mag ni tude of de nu da tion in intraplateau sed i men tary bas ins dur ing the Late Vistulian and Ho lo cene (in Pol ish with Eng lish sum mary). Seria Geografia, 54. Wydawnictwo UAM, Poznañ.
Bronk Ramsey, C., 2009. Bayesian anal y sis of ra dio car bon dates. Ra dio car bon, 51: 337–360.
Co hen, A.S., 2003. Paleolimnology: the His tory and Evo lu tion of Lake Sys tems. Ox ford Uni ver sity Press, New York.
Coo per, C.M., Knight, S.S., 1990. Nu tri ent trap ping ef fi ciency of a small sed i ment de ten tion res er voir. Ag ri cul tural Wa ter Man age -ment, 18: 149–158.
Drexler, J.Z., Bed ford, B.L., Scognamiglio, R., Siegel, D.I., 1999. Fine-scale char ac ter is tics of ground wa ter flow in a peatland. Hy dro log i cal Pro cesses, 13: 1341–1359.
Dyakowska, J., 1959. Podrêcznik palynologii (in Pol ish). Metody i problemy. Wyd. Geol., Warszawa.
Folk, R.L., Ward, W.C., 1957. Brazos River bar: a study in the sig nif i cance of grain size pa ram e ters. Jour nal of Sed i men tary Pe trol -ogy, 27: 3–26.
Forysiak, J., 2015. Geomorphological di ver sity of peatland bas ins in the £ódŸ re gion and its sig nif i cance for the ac cu mu la tion of biogenic sed i ments. Bul le tin of Ge og ra phy, Phys i cal Ge og ra phy Se ries, 8: 59–70.
Franz, S.O., Schwark, L., Bruchmann, C., Scharf, B., Klingel, R., Van Alstine, J.D., Cagatay, N., Ulgen, U.B., 2006. Re sults from a multi-dis ci plin ary sed i men tary pi lot study of tec tonic Lake Iznik (NW Tur key) – geo chem is try and paleolimnology of the re -cent past. Jour nal of Paleolimnology, 35: 715–736.
Fra ser, C.J., Roulet, N.T., Lafleur, P.M., 2001. Ground wa ter flow pat terns in a large peatland. Jour nal of Hy drol ogy, 246: 142–154. Frielinghaus, M., Vahrson, W.G., 1998. Soil translocation by wa ter
ero sion from ag ri cul tural cropland into wet de pres sions (morainic ket tle holes). Soil and Till age Re search, 46: 23–30. Gamrat, W.W., Andrzejewski, L., Krzeœlak, I., 2014. Postglacjalne
zmiany œrodowiska przyrodniczego na WysoczyŸnie Dobrzyñ -skiej zapisane na profilu osadów biogenicznych w Piotrkowie (in Pol ish). Landform Anal y sis, 25: 3–11.
Gorham, E., Rochefort, L., 2003. Peatland res to ra tion: a brief as -sess ment with spe cial ref er ence to Sphag num bogs. Wetlands Ecol ogy and Man age ment, 11: 109–119.
Hirsch, F., Schnei der, A., Nicolay, A., B³aszkiewicz, M., Kordo -wski, J., Noryœkiewicz, A.M., Tyszko-wski, S., Raab, A., Raab, T., 2015. Late Qua ter nary land scape de vel op ment at the mar gin of the Pom er a nian phase (MIS 2) near Lake Wygonin (North ern Po land). Catena, 124: 28–44.
IUSS Work ing Group WRB, 2015. World Ref er ence Base for Soil Re sources 2014. In ter na tional Soil Clas si fi ca tion Sys tem for Nam ing Soils and Cre at ing Leg ends for Soil Maps. World Soil Re sources Re ports No. 106. FAO, Rome.
Jäger, H., Achermann, M., Waroszewski, J., Kaba³a, C., Malkiewicz, M., Gärtner, H., Dahms, D., Krebs, R., Egli, M., 2015. Preal pine mire sed i ments as a mir ror of ero sion, soil for -ma tion and land scape evo lu tion dur ing the last 45 ka. Catena, 128: 63–79.
Kalettka, T., Rudat, C., 2006. Hydrogeomorphic types of gla cially cre ated ket tle holes in North-East Ger many. Limnologica, 36: 54–64.
Karasiewicz, M.T., 2006a. Max i mum range and lay out of the mar -ginal zone of the Vistulian ice sheet dur ing the Pom er a nian phase in the vi cin ity of lake Narie. Quaestiones Geographicae, 25A: 27–37.
Karasiewicz, M.T., 2006b. Morfogeneza obszaru w okolicy Mor¹ga (in Pol ish). Dokumentacja Geograficzna, 32: 129–134. Karasiewicz, M.T., Hulisz, P., Œwitoniak, M. eds., 2012. Post
-glacjalna historia zag³êbienia bezodp³ywowego w rezerwacie Retno (Pojezierze Brodnickie) (in Pol ish). Wydawnictwa Nauko -we UMK, Toruñ: 1–161.
Karasiewicz, M.T., Hulisz, P., Œwitoniak, M., 2014a. Wp³yw procesów denudacji na w³aœciwoœci osadów wype³niaj¹cych zag³êbienia miêdzy krêtymi wa³ami z erozji wód subglacjalnych w okolicy Zbójna (Pojezierze Dobrzyñskie) (in Pol ish). Landform Anal y sis, 25: 29–42.
Karasiewicz, M.T., Hulisz, P., Noryœkiewicz, A.M., Krzeœlak. I., Œwitoniak, M., 2014b. The re cord of hydroclimatic changes in the sed i ments of a ket tle-hole in a young gla cial land scape (north-cen tral Po land). Qua ter nary In ter na tional, 328–329: 264–276.
Kleeberg, A., Neyen, M., Schkade, U.-K., Kalettka, T., Lischeid, G., 2015. Sed i ment cores from ket tle holes in NE as so ci ated phos pho rus, from in ten sively farmed grass lands. En vi ron men tal Sci ence and Pol lu tion Re search, 23: 7409–7424.
Kochanowska, R., Pieñkowski, P., Podlasiñski, M., 1998. Char ac ter is tics of intrafield wa ter holes in West ern Pomerania in re la -tion to differen-tion of the Young-gla cial land scape and hu man im pact. Jour nal of Wa ter Land De vel op ment, 2: 85–101. Kowalewski, G., 2014. Alogeniczne i autogeniczne sk³adowe
zarastania jezior: hipoteza wahañ poziomu wody (in Pol ish). Studia Limnologica et Telmatica, Monographiae, I: 1–191. Krzeœlak, I., Andrzejewski, L., Gamrat, W., Kupniewska, A.,
2014. PóŸnoglacjalna i holoceñska ewolucja torfowiska w Dziko wie (Kotlina Toruñska) w œwietle badañ paleo geogra -ficznych (in Pol ish). Landform Anal y sis, 25: 95–103.
Kupryjanowicz, M., Filbrandt-Czaja, A., Noryœkiewicz, A.M., Noryœkiewicz, B., Nalepka, D., 2004. Tilia L – Lime. In: Late Gla cial and Ho lo cene his tory of veg e ta tion in Po land based on isopollen maps (eds. M. Ralska-Jasiewiczowa, M. Lata³owa, K. Wasylikowa, K. Tobolski, E. Madeyska, H.E.Jr. Wright and Ch. Turner): 217–224. W. Szafer In sti tute of Bot any, Pol ish Acad -emy of Sci ences, Kraków.
Küster, M., Ruchhöft, F., Lorenz, S., Janke, W., 2011. Geoarchaeological ev i dence of Ho lo cene hu man im pact and soil ero sion on a till plain in Vorpommern (Kühlenhagen, NE-Ger many). Qua ter nary Sci ence Jour nal, 60: 455–463. Lamentowicz, M., Tobolski, K., Mitch ell, E.A.D., 2007. Palaeo eco
-logi cal ev i dence for anthropogenic acid i fi ca tion of a kettle hole peatland in north ern Po land. The Ho lo cene, 17: 1185–1196. Lamentowicz, M., Obremska, M., Mitch ell, E.A.D., 2008. Auto
-genic suc ces sion, land-use change, and cli ma tic in flu ences on the Ho lo cene de vel op ment of a ket tle hole mire in North ern Po -land. Re view of Palaeobotany and Palynology, 151: 21–40. Lamentowicz, M., Forysiak, J., Balwierz, Z., Kloss, M., Kittel, P.,
¯urek, S., Pawlyta, J., 2009. Multiproxy study of anthropogenic and cli ma tic changes in the last two mil len nia from a small mire in cen tral Po land. Hydrobiologia, 631: 213–230.
Ma jor, M., 2009. Charakter i funkcjonowanie zag³êbieñ bez -odp³ywowych w krajobrazie strefy m³odoglacjalnej (Pomorze Zachodnie, górna Parsêta) (in Pol ish). Wydawnictwo Poznañ -skiego TPN, Poznañ: 1–176.
Malkiewicz, M., Waroszewski, J., Bojko, O., Egli, M., Ka ba la, C., 2016. Ho lo cene veg e ta tion his tory and soil de vel op ment re flected in the lake sed i ments of the Karkonosze Moun tains (Po -land). The Ho lo cene, 26: 890–905.
Markiewicz, M., Mendyk, £., Gonet, S.S., 2015. Soil or ganic mat ter sta tus in ag ri cul tural soil se quence of for mer shore line of dis ap pear ing Sumowskie Lakes, NorthEast ern Po land. Pol ish Jour -nal of Soil Sci ence, 48: 65–78.
Mendyk, £., Markiewicz, M., Bednarek, R., Œwitoniak, M., Gam -rat, W.W., Krzeœlak, I., Syku³a, M., Gersztyn, L., Kupniewska, A., 2015. En vi ron men tal changes of a shal low ket tle lake catch ment in a young gla cial land scape (Sumowskie Lake catch -ment), North-Cen tral Po land. Qua ter nary In ter na tional, 413: 116–131.
Nalepka, D., Walanus, A., 2003. Data pro cess ing in pol len anal y -sis. Acta Palaeobotanica, 43: 125–134.
Niewiarowski, W., 1989. Wahania poziomu jezior w póŸnym gla -cjale i holocenie na przyk³adzie jezior Pojezierza Brodnickiego (in Pol ish). Studia i Materia³y Oceanologiczne, 56: 277–288. Niewiarowski, W. ed., 1995. Zarys zmian œrodowiska geogra
-ficznego okolic Biskupina pod wp³ywem czynników naturalnych i antropogenicznych w póŸnym glacjale i holocenie (in Pol ish). Oficyna Wydawnicza Turpress, Toruñ.
Noryœkiewicz, B., 1987. His tory of veg e ta tion dur ing the LateGla -cial and Ho lo cene in Brodnica Lake Dis trict in the light of pol len anal y sis of Lake Stra¿ym deposists. Acta Palaeobotanica, 27: 283–304.
Noryœkiewicz, A.M., 2006. Historia cisa w okolicy Wierzchlasu w œwietle analizy py³kowej (in Pol ish with Eng lish sum mary). Wyda -wni ctwo Naukowe Uniwersytetu Miko³aja Kopernika, Toruñ. Noryœkiewicz, A.M., 2013. Veg e ta tion and settlenent his tory of the
Che³mno Land in Late Ho lo cene. Palynological study (in Pol ish with Eng lish sum mary). Wydawnictwo Naukowe Uniwersytetu Miko³aja Kopernika, Toruñ.
Podlasiñska, J., 2012. Zró¿nicowanie i chemizm osadów ma³ych zbiorników wodnych w krajobrazie m³odoglacjalnym (in Pol ish). Zachodniopomorski Uniwersytet Technologiczny, Szczecin. Podlasiñski, M., 2013. Wp³yw denudacji antropogenicznej na
zró¿nicowanie pokrywy glebowej i jej przestrzenn¹ strukturê w rolniczym krajobrazie morenowym (in Pol ish). Wydawnictwo Uczelniane Zachodniopomorskiego Uniwersytetu Technolo -gicznego w Szczecinie.
Ralska-Jasiewiczowa, M., Goslar, T., Madeyska, T., Starkel, L. eds., 1998. Lake Goœci¹¿, Cen tral Po land. A Mono graphic Study (Part 1). W. Szafer In sti tute of Bot any, Kraków.
Roszkówna, L., 1955. Endmorains of the west ern Mazurian lake coun try (in Pol ish with Eng lish summary). Studia Societatis Scientiarum Toruniensis, 2: 35–95.
Sinkiewicz, M., 1998. Rozwój denudacji antropogenicznej w œrodkowej czêœci Polski Pó³nocnej (in Pol ish). Wydawnictwo Uniwersytetu Miko³aja Kopernika, Toruñ: 1–103.
Smolska, E., 2005. Znaczenie sp³ukiwania w modelowaniu stoków m³odoglacjalnych (na przyk³adzie Pojezierza Suwalskiego) (in Pol ish). WGiSR UW Warszawa: 1–146.
Stachowicz-Rybka, R., 2011. Flora and veg e ta tion changes on the ba sis of plant macroremains anal y sis from an early Pleis to cene
lake of the Augustów Plain, NE Po land. Acta Palaeobotanica, 51: 39–104.
Starkel, L., Pazdur, A., Pazdur, M.F., Wicik, B., Wiêckowski, K., 1998. Lakelevel changes and palaeohydrological re con struc -tions dur ing the Ho lo cene. In: Lake Goœci¹¿, Cen tral Po land, a Mono graphic Study, Part 1 (eds. M. Ralska-Jasiewiczowa, T. Goslar, T. Madeyska and L. Starkel): 225–229. Instytut Botaniki PAN, Kraków.
Stockmarr, J., 1971. Tab lets with spores of ab so lute pol len anal y -sis. Pol len et Spores, 13: 615–621.
Szoszkiewicz, K., Jusik, Sz., Zgo³a, T., 2010. Guide for iden ti fi ca -tion of macrophytes for as sess ment of the eco log i cal state of freshwaters (in Pol ish with Eng lish sum mary). Biblioteka Monitoringu Œrodowiska, Warszawa.
Szwarczewski, P., 2008. Uwagi o wieku póŸnoglacjalnych i holoceñskich osadów organicznych i tempie ich akumulacji na przyk³adzie okolic Sejn (in Pol ish). Pol ish Acad emy of Sci ence Kraków, Geobotanical Guide books, 30: 183–194.
Szwarczewski, P., Kupryjanowicz, M., 2008. Etapy rozwoju zag³êbieñ bezodp³ywowych w okolicach Sejn (in Pol ish). Pol ish Acad emy of Sci ence Kraków, Geobotanical Guide books, 30: 195–205.
Œrodoñ, A., 1991. Lipa w minionych krajobrazach Polski (in Pol ish). In: Lipy „Tilia cordata Mill.”, „Tilia platyphyllos Scop.” (ed. W. Ba³aga): 9–19. Ar ca dia, Kórnik-Poznañ.
Œwitoniak, M., 2014. Use of soil pro file trun ca tion to es ti mate in flu -ence of ac cel er ated ero sion on soil cover trans for ma tion in young morainic land scapes, North-East ern Po land. Catena, 116: 173–184.
Œwitoniak, M., 2015. Is sues re lat ing to clas si fi ca tion of col lu vial soils in young morainic ar eas (Che³mno and Brodnica Lake Dis -trict, north ern Po land). Soil Sci ence An nual, 66: 57–66. Œwitoniak, M., Mroczek, P., Bednarek, R., 2016. Luvisols or
Cambi sols? Micromorphological study of soil trun ca tion in young morainic land scapes – case study: Brodnica and Che³mno Lake Dis tricts (North Po land). Catena, 137: 583–595. Timmermann, T., Succow, M., 2001. Kesselmoore. In: Land
-schafts -ökologische Moorkunde. 2. Aufl (eds. M. Succow and H. Joosten): 379–390. E.Schweizerbart, Stuttgart.
Tobolski, K., 2003. Torfowiska na przyk³adzie Ziemi Œwieckiej (in Pol ish). TPDW, Œwiecie.
Twardy, J., ¯urek, S., Forysiak, J. eds., 2010. Torfowisko ¯abie niec, warunki naturalne, rozwój i zapis zmian paleoekolo -gicznych w jego osadach (in Pol ish). Bogucki Wydawnictwo Naukowe, Poznañ.
Van Loon, A.J., B³aszkiewicz, M., Degórski, M., 2012. The role of per ma frost in shap ing the Late Gla cial re lief of north ern Po land. Neth er lands Jour nal of Geosciences, 91: 223–231.
Wacnik, A., 2009. Galindowie i Krzy¿acy – oddzia³ywania na lokaln¹ roœlinnoœæ w rejonie Mi³ek i Staœwin (Kraina Wielkich Jezior Mazurskich, Pó³nocno-wschodnia Polska) (in Pol ish). Wiadomoœci Botaniczne, 53: 21–34.
Wacnik, A., 2012. Veg e ta tion changes caused by ag ri cul tural socie -tatis in the Great Mazurian Lake Dis trict. Acta Palaeobotanica, 52: 59–104.
Wiêckowski, K., 1989. A new method of cor ing in deep lakes with rod op er ated sam plers. Boreas, 18: 357–358.
Wysota, W., Noryœkiewicz, B., 2011. Geo mor phol ogy and veg e ta -tion his tory of the Rypienica chan nel, the Dobrzyñ Lakeland, North Po land. Bul le tin of Ge og ra phy, Phys i cal Ge og ra phy Se -ries, 4: 71–88.
